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Nikravesh F, Mirzaee Khalilabadi R, Farsinejad A, Mardani Valandani H. Platelet microparticles influence gene expression and modulate biological activities of chronic myeloid leukemia cells (K562). Mol Biol Rep 2024; 51:676. [PMID: 38796661 DOI: 10.1007/s11033-024-09383-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 02/26/2024] [Indexed: 05/28/2024]
Abstract
BACKGROUND The current understanding emphasizes the intricate interplay between the Leukemic cell and its environment. Platelet-derived microparticles play a crucial role in facilitating intercellular communication and contribute to the complex landscape of cancer pathology. This study aimed to investigate the influence of platelet-derived microparticles on cell proliferation, apoptosis, and the expression of key genes, including P53, P21, Cyclin D1, Bax, and Bcl-2, within the context of a chronic myeloid leukemia cell line (K562). METHODS AND RESULTS Platelet-derived microparticles were obtained through centrifugation at various speeds, and their concentration was quantified using the BCA assay. To determine the size and immunophenotypic characteristics of the PMPs, both the DLS technique and flow cytometry were employed. Cell proliferation was assessed using the MTT assay and hemocytometer, and cell cycle analysis was conducted through DNA content evaluation. Real-time PCR was utilized for gene expression analysis of Bax, Bcl-2, Cyclin D1, P53, and P21. Flow cytometry was employed to examine cell apoptosis. The findings revealed that platelet-derived microparticles have the ability to decrease proliferation of the K562 cell line, while not exerting an impact on apoptosis and cell cycle progression. Analysis through real-time PCR indicated an upregulation in the gene expression of P53, P21, and Bcl-2, accompanied by a downregulation in Bax and Cyclin D1. CONCLUSION This investigation sheds light on the intricate relationship between chronic myeloid leukemia and its microenvironment, particularly the involvement of platelet-derived microparticles. The study underscores the potential of platelet-derived microparticles to influence cell behavior and gene expression, providing a deeper understanding of their role in CML and its therapeutic implications.
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MESH Headings
- Humans
- Cell-Derived Microparticles/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Blood Platelets/metabolism
- K562 Cells
- Cell Proliferation/genetics
- Apoptosis/genetics
- Cell Cycle/genetics
- bcl-2-Associated X Protein/metabolism
- bcl-2-Associated X Protein/genetics
- Cyclin D1/metabolism
- Cyclin D1/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Proto-Oncogene Proteins c-bcl-2/genetics
- Gene Expression Regulation, Leukemic
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Affiliation(s)
- Fariba Nikravesh
- Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medicine, Kerman University of Medical Sciences, Medical University Campus, Haft-Bagh Highway, Kerman, Iran
| | - Roohollah Mirzaee Khalilabadi
- Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medicine, Kerman University of Medical Sciences, Medical University Campus, Haft-Bagh Highway, Kerman, Iran
| | - Alireza Farsinejad
- Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medicine, Kerman University of Medical Sciences, Medical University Campus, Haft-Bagh Highway, Kerman, Iran
- Cell Therapy and Regenerative Medicine Comprehensive Center, Kerman University of Medical Sciences, Medical University Campus, Haft-Bagh Highway, Kerman, Iran
| | - Hajar Mardani Valandani
- Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medicine, Kerman University of Medical Sciences, Medical University Campus, Haft-Bagh Highway, Kerman, Iran.
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Li Y, Huang X, Tang J. Inhibiting the growth of ovarian cancer cells in vitro and in vivo by a small molecular inhibitor targeting La-RNA interactions. Eur J Pharmacol 2023; 940:175471. [PMID: 36549502 DOI: 10.1016/j.ejphar.2022.175471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To identify small molecules blocking La-RNA interactions by using structural dynamics, molecular biology, and in vivo efficacy experiments. METHODS A docking virtual assay on the Chemdiv database was used to screen La binders, and their affinity were measured by surface plasmon resonance (SPR). A novel fluorescence polarization (FP) assay referring to the binding of La protein and 3'UUUOH was established to identify the inhibitors. Their activity on ovarian cancer cell proliferation, apoptosis and cell cycle were evaluated using Cell Counting Kit 8 (CCK8) and flow cytometry assay, respectively. Their in vivo efficacy against ovarian cancer growth were evaluated in a cell line-derived xenograft (CDX) model of A2780 cells. RESULTS From a total of 20 compounds with high potential binding activity with La protein, two small molecule compounds 4424-1120 and 8017-5932 with relatively stronger inhibition ability on La-RNA interactions were identified. These two compounds shared the same active centers with hydroxyimidazole and hydroxybenzene to interact with La protein through residues ARG57, GLN20 and GLN136. The in vitro assays showed that 4424-1120 and 8017-5932 effectively cause G0/G1 cell cycle arrest, inhibit cell proliferation, reduce cell invasion and promote apoptosis in ovarian cancer cells. In a CDX model on BALB/C Nude mice, we found that the growth rate of the tumor was inhibited by 4424-1120. CONCLUSION Our results demonstrated compound 4424-1120 shows good antitumor activity and safety in vitro and in vivo, and it provides a new idea for the discovery of antitumor lead compounds from small drug-like molecules.
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Affiliation(s)
- Yueyan Li
- Department of Pharmacy, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, People's Republic of China
| | - Xuan Huang
- Department of Pharmacy, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, People's Republic of China
| | - Jing Tang
- Department of Pharmacy, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, People's Republic of China.
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Upregulated SSB Is Involved in Hepatocellular Carcinoma Progression and Metastasis through the Epithelial-Mesenchymal Transition, Antiapoptosis, and Altered ROS Level Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2023; 2023:5207431. [PMID: 36785788 PMCID: PMC9922187 DOI: 10.1155/2023/5207431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/31/2022] [Accepted: 11/25/2022] [Indexed: 02/05/2023]
Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Therefore, finding new diagnostic and therapeutic targets is vital for HCC patients. Recent studies have shown that dysregulation of RNA-binding proteins is often associated with cancer progression. Several studies have reported that the RNA-binding protein SSB can promote cancer occurrence and progression and is linked to tumor epithelial-mesenchymal transition (EMT), which could be a new diagnostic marker and therapeutic target. However, the expression and function of SSB in HCC remain to be elucidated. Therefore, this study is aimed at clarifying the expression and biological function of SSB in HCC through bioinformatics analysis combined with in vitro experiments. We found that SSB is highly expressed in HCC and is associated with the poor prognosis of HCC patients, and it can serve as an independent unfavorable prognostic factor. Knockdown of SSB can inhibit the growth of HCC cells in vitro, increase the level of apoptosis and the expression of pro-apoptosis-related proteins, and decrease the expression of antiapoptotic proteins. Meanwhile, SSB knockdown reduced HCC cell invasiveness, and the expression of EMT-related proteins changed significantly. We also found that the gene SSB was associated with the level of oxidative stress in liver cancer cells, and the level of intracellular reactive oxygen species (ROS) increased after knockdown of SSB. The results of bioinformatics analysis also showed that high expression of SSB may affect the effect of checkpoint blockade (ICB) therapy. In conclusion, we found that SSB is highly expressed in HCC and that upregulated SSB can promote the proliferation and metastasis of HCC through antiapoptotic, altered intracellular oxidative stress level, and EMT pathways, which can serve as a new diagnostic marker and therapeutic target, and patients with high SSB expression may not have obvious ICB therapy effect.
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Cell surface-bound La protein regulates the cell fusion stage of osteoclastogenesis. Nat Commun 2023; 14:616. [PMID: 36739273 PMCID: PMC9899215 DOI: 10.1038/s41467-023-36168-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/16/2023] [Indexed: 02/06/2023] Open
Abstract
Multinucleated osteoclasts, essential for skeletal remodeling in health and disease, are formed by the fusion of osteoclast precursors, where each fusion event raises their bone-resorbing activity. Here we show that the nuclear RNA chaperone, La protein has an additional function as an osteoclast fusion regulator. Monocyte-to-osteoclast differentiation starts with a drastic decrease in La levels. As fusion begins, La reappears as a low molecular weight species at the osteoclast surface, where it promotes fusion. La's role in promoting osteoclast fusion is independent of canonical La-RNA interactions and involves direct interactions between La and Annexin A5, which anchors La to transiently exposed phosphatidylserine at the surface of fusing osteoclasts. Disappearance of cell-surface La, and the return of full length La to the nuclei of mature, multinucleated osteoclasts, acts as an off switch of their fusion activity. Targeting surface La in a novel explant model of fibrous dysplasia inhibits excessive osteoclast formation characteristic of this disease, highlighting La's potential as a therapeutic target.
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Huang X, Zhu J, Li Y, Yu Y, Tang J. La protein regulates protein expression by binding with the mRNAs of target genes and participates the pathological process of ovarian cancer. Front Oncol 2022; 12:763480. [PMID: 36110943 PMCID: PMC9468491 DOI: 10.3389/fonc.2022.763480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 08/08/2022] [Indexed: 12/03/2022] Open
Abstract
Research on the mechanism and new targets of ovarian cancer is of great significance to reduce the high mortality and drug resistance of ovarian cancer. Human La protein has been found to be highly expressed in a variety of malignant tumors and plays a role in tumorigenesis and development through its RNA-binding function. However, its role and mechanism in ovarian cancer are not completely clear. The present study showed that La protein was highly expressed in serum and tissues of patients with ovarian cancer by ELISA and immunohistochemistry, and the high expression of La protein was associated with the increased degree of malignancy and poor prognosis by searching the KM plotter database. Interference of the La gene resulted in a significant decrease in the proliferation, migration, and invasion of ovarian cancer cells with growth block in the G1 phase and increasing apoptosis. By RNA binding protein immunoprecipitation, transcriptome sequencing, and proteomics, 14 downstream target genes were screened. The La protein might affect the protein expression of these 14 genes by binding with the mRNAs. Therefore, it played a role in the pathological process of ovarian cancer.
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Aldaalis A, Bengoechea-Alonso MT, Ericsson J. The SREBP-dependent regulation of cyclin D1 coordinates cell proliferation and lipid synthesis. Front Oncol 2022; 12:942386. [PMID: 36091143 PMCID: PMC9451027 DOI: 10.3389/fonc.2022.942386] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/25/2022] [Indexed: 12/15/2022] Open
Abstract
The sterol regulatory-element binding protein (SREBP) family of transcription factors regulates cholesterol, fatty acid, and triglyceride synthesis and metabolism. However, they are also targeted by the ubiquitin ligase Fbw7, a major tumor suppressor, suggesting that they could regulate cell growth. Indeed, enhanced lipid synthesis is a hallmark of many human tumors. Thus, the SREBP pathway has recently emerged as a potential target for cancer therapy. We have previously demonstrated that one of these transcription factors, SREBP1, is stabilized and remains associated with target promoters during mitosis, suggesting that the expression of these target genes could be important as cells enter G1 and transcription is restored. Activation of cyclin D-cdk4/6 complexes is critical for the phosphorylation and inactivation of the retinoblastoma protein (Rb) family of transcriptional repressors and progression through the G1 phase of the cell cycle. Importantly, the cyclin D-cdk4/6-Rb regulatory axis is frequently dysregulated in human cancer. In the current manuscript, we demonstrate that SREBP1 activates the expression of cyclin D1, a coactivator of cdk4 and cdk6, by binding to an E-box in the cyclin D1 promoter. Consequently, inactivation of SREBP1 in human liver and breast cancer cell lines reduces the expression of cyclin D1 and attenuates Rb phosphorylation. Rb phosphorylation in these cells can be rescued by restoring cyclin D1 expression. On the other hand, expression of active SREBP1 induced the expression of cyclin D1 and increased the phosphorylation of Rb in a manner dependent on cyclin D1 and cdk4/6 activity. Inactivation of SREBP1 resulted in reduced expression of cyclin D1, attenuated phosphorylation of Rb, and reduced proliferation. Inactivation of SREBP1 also reduced the insulin-dependent regulation of the cyclin D1 gene. At the same time, SREBP1 is known to play an important role in supporting lipid synthesis in cancer cells. Thus, we propose that the SREBP1-dependent regulation of cyclin D1 coordinates cell proliferation with the enhanced lipid synthesis required to support cell growth.
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Affiliation(s)
- Arwa Aldaalis
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Doha, Qatar
| | - Maria T. Bengoechea-Alonso
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Doha, Qatar
| | - Johan Ericsson
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Doha, Qatar
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
- *Correspondence: Johan Ericsson,
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Staudacher AH, Li Y, Liapis V, Brown MP. The RNA-binding protein La/SSB associates with radiation-induced DNA double-strand breaks in lung cancer cell lines. Cancer Rep (Hoboken) 2022; 5:e1543. [PMID: 34636174 PMCID: PMC9351668 DOI: 10.1002/cnr2.1543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/13/2021] [Accepted: 08/06/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Platinum-based chemotherapy and radiotherapy are standard treatments for non-small cell lung cancer, which is the commonest, most lethal cancer worldwide. As a marker of treatment-induced cancer cell death, we have developed a radiodiagnostic imaging antibody, which binds to La/SSB. La/SSB is an essential, ubiquitous ribonuclear protein, which is over expressed in cancer and plays a role in resistance to cancer therapies. AIM In this study, we examined radiation-induced DNA double strand breaks (DSB) in lung cancer cell lines and examined whether La/SSB associated with these DSB. METHOD Three lung cancer lines (A549, H460 and LL2) were irradiated with different X-ray doses or X-radiated with a 5 Gy dose and examined at different time-points post-irradiation for DNA DSB in the form of γ-H2AX and Rad51 foci. Using fluorescence microscopy, we examined whether La/SSB and γ-H2AX co-localise and performed proximity ligation assay (PLA) and co-immunoprecipitation to confirm the interaction of these proteins. RESULTS We found that the radio-resistant A549 cell line compared to the radio-sensitive H460 cell line showed faster resolution of radiation-induced γ-H2AX foci over time. Conversely, we found more co-localised γ-H2AX and La/SSB foci by PLA in irradiated A549 cells. CONCLUSION The co-localisation of La/SSB with radiation-induced DNA breaks suggests a role of La/SSB in DNA repair, however further experimentation is required to validate this.
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Affiliation(s)
- Alexander H. Staudacher
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
- School of MedicineUniversity of AdelaideAdelaideSouth Australia5000Australia
| | - Yanrui Li
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
| | - Vasilios Liapis
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
| | - Michael P. Brown
- Translational Oncology Laboratory, Centre for Cancer BiologySA Pathology and University of South AustraliaAdelaideSouth Australia5000Australia
- School of MedicineUniversity of AdelaideAdelaideSouth Australia5000Australia
- Cancer Clinical Trials UnitRoyal Adelaide HospitalAdelaideSouth Australia5000Australia
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Xiong YW, Feng YJ, Wei T, Zhang X, Tan LL, Zhang J, Dai LM, Zhu HL, Zhou GX, Liu WB, Liu ZQ, Xu XF, Gao L, Zhang C, Wang Q, Xu DX, Wang H. miR-6769b-5p targets CCND-1 to regulate proliferation in cadmium-treated placental trophoblasts: Association with the impairment of fetal growth. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 230:113109. [PMID: 34953275 DOI: 10.1016/j.ecoenv.2021.113109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
Environmental cadmium (Cd) is positively associated with placental impairment and fetal growth retardation. Nevertheless, its potential mechanisms remain unclear. microRNAs (miRNAs) are known to influence placental development and fetal growth. This work was aimed to determine which miRNAs are involved in Cd-impaired placental and fetal development based on the mRNA and miRNA expression profiles analysis. As a result, gestational Cd exposure deceased fetal and placental weight, and reduced the protein level of PCNA in human and mouse placentae. Furthermore, the results of mRNA microarray showed that Cd-downregulated mRNAs were predictively correlated with several biological processes, including cell proliferation, differentiation and motility. In addition, the results of miRNA microarray and qPCR assay demonstrated that Cd significantly increased the level of miR-6769b-5p, miR-146b-5p and miR-452-5p. Integrated analysis of Cd-upregulated miRNAs predicted target genes and Cd-downregulated mRNAs found that overlapping mRNAs, such as CCND1, CDK13, RINT1 and CDC26 were also significantly associated with cell proliferation. Further experiments showed that miR-6769b-5p inhibitor, but not miR-146b-5p and miR-452-5p, markedly reversed Cd-downregulated the expression of proliferation-related mRNAs, and thereby restored Cd-decreased the proteins level of CCND1 and PCNA in human placental trophoblasts. Dual luciferase reporter assay further revealed that miR-6769b-5p directly targets CCND1. Finally, the case-control study demonstrated that increased miR-6769b-5p level and impaired cell proliferation were observed in small-for-gestational-age human placentae. In conclusion, miR-6769b-5p targets CCND-1 to regulate proliferation in Cd-treated placental trophoblasts, which is associated with the impairment of fetal growth. Our findings imply that placental miR-6769b-5p may be used as an epigenetic marker for environmental pollutants-caused fetal growth restriction and its late-onset chronic diseases.
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Affiliation(s)
- Yong-Wei Xiong
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Yu-Jie Feng
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Tian Wei
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Xiang Zhang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Lu-Lu Tan
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Jin Zhang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Li-Min Dai
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Hua-Long Zhu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Guo-Xiang Zhou
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Wei-Bo Liu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Zi-Qi Liu
- Department of Toxicology, School of Public Health, Sun Yat-sen University, China
| | - Xiao-Feng Xu
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, China
| | - Lan Gao
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Cheng Zhang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Qing Wang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, China.
| | - De-Xiang Xu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China.
| | - Hua Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China.
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Liapis V, Tieu W, Wittwer NL, Gargett T, Evdokiou A, Takhar P, Rudd SE, Donnelly PS, Brown MP, Staudacher AH. Positron Emission Tomographic Imaging of Tumor Cell Death Using Zirconium-89-Labeled APOMAB® Following Cisplatin Chemotherapy in Lung and Ovarian Cancer Xenograft Models. Mol Imaging Biol 2021; 23:914-928. [PMID: 34231102 PMCID: PMC8578059 DOI: 10.1007/s11307-021-01620-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/28/2021] [Accepted: 05/26/2021] [Indexed: 02/02/2023]
Abstract
PURPOSE Early detection of tumor treatment responses represents an unmet clinical need with no approved noninvasive methods. DAB4, or its chimeric derivative, chDAB4 (APOMAB®) is an antibody that targets the Lupus associated antigen (La/SSB). La/SSB is over-expressed in malignancy and selectively targeted by chDAB4 in cancer cells dying from DNA-damaging treatment. Therefore, chDAB4 is a unique diagnostic tool that detects dead cancer cells and thus could distinguish between treatment responsive and nonresponsive patients. PROCEDURES In clinically relevant tumor models, mice bearing subcutaneous xenografts of human ovarian or lung cancer cell lines or intraperitoneal ovarian cancer xenografts were untreated or given chemotherapy followed 24h later by chDAB4 radiolabeled with [89Zr]ZrIV. Tumor responses were monitored using bioluminescence imaging and caliper measurements. [89Zr]Zr-chDAB4 uptake in tumor and normal tissues was measured using an Albira SI Positron-Emission Tomography (PET) imager and its biodistribution was measured using a Hidex gamma-counter. RESULTS Tumor uptake of [89Zr]Zr-chDAB4 was detected in untreated mice, and uptake significantly increased in both human lung and ovarian tumors after chemotherapy, but not in normal tissues. CONCLUSION Given that tumors, rather than normal tissues, were targeted after chemotherapy, these results support the clinical development of chDAB4 as a radiodiagnostic imaging agent and as a potential predictive marker of treatment response.
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Affiliation(s)
- Vasilios Liapis
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia.
| | - William Tieu
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
- Molecular Imaging and Therapy Research Unit (MITRU), South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Nicole L Wittwer
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
| | - Tessa Gargett
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
| | - Andreas Evdokiou
- Discipline of Surgery, Breast Cancer Research Unit, Basil Hetzel Institute and Centre for Personalised Cancer Medicine, University of Adelaide, Woodville, SA, 5011, Australia
| | - Prab Takhar
- Molecular Imaging and Therapy Research Unit (MITRU), South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Stacey E Rudd
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Paul S Donnelly
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Michael P Brown
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
- Cancer Clinical Trials Unit, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
| | - Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Level 9 University of South Australia Health Innovation Building, North Terrace, Adelaide, 5000, Australia
- School of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia
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Huang C, Liang J, Lin S, Wang D, Xie Q, Lin Z, Yao T. N 6-Methyladenosine Associated Silencing of miR-193b Promotes Cervical Cancer Aggressiveness by Targeting CCND1. Front Oncol 2021; 11:666597. [PMID: 34178650 PMCID: PMC8222573 DOI: 10.3389/fonc.2021.666597] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/17/2021] [Indexed: 12/31/2022] Open
Abstract
Objective Cervical cancer is a frequently encountered gynecological malignancy as a major contributor to cancer-related deaths in women. This study focuses on how miR-193b promotes cervical cancer aggressiveness as well as the role of m6A in miR-193b silencing. Methods Cervical cancer samples and the matching adjacent normal cervical tissues were used to determine the significance of miR-193b in cervical cancer. The CCK-8 assay, cell cycle analysis, qRT-PCR, Western blot assay, IHC, RIP, and xenograft models were utilized to explore the impact of miR-193b in cervical cancer and how m6A regulates miR-193b expression. Luciferase reporter assays, qRT-PCR, and Western blotting were enlisted to study the interaction between miR-193b and CCND1. Results Our study suggested that lower miR-193b expressions were strongly linked to more advanced cervical cancer stages and the presence of deeper stromal invasion. miR-193b functions as a tumor suppressor that is regulated by m6A methylation in cervical tumors. METTL3 modulates miR-193b mature process in an m6A-dependent manner. Reintroduction of miR-193b profoundly inhibits tumorigenesis of cervical cancer cells both in vivo and in vitro through CCND1 targeting. Conclusions m6A associated downregulation of miR-193b promotes cervical cancer aggressiveness by targeting CCND1.
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Affiliation(s)
- Chunxian Huang
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jinxiao Liang
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Shaodan Lin
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Dongyan Wang
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qingsheng Xie
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zhongqiu Lin
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Tingting Yao
- Department of Gynecological Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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11
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STAU2 protein level is controlled by caspases and the CHK1 pathway and regulates cell cycle progression in the non-transformed hTERT-RPE1 cells. BMC Mol Cell Biol 2021; 22:16. [PMID: 33663378 PMCID: PMC7934504 DOI: 10.1186/s12860-021-00352-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 02/22/2021] [Indexed: 11/10/2022] Open
Abstract
Background Staufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from the STAU2 gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation. Results CRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism. Conclusions These results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s12860-021-00352-y.
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12
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Bayfield MA, Vinayak J, Kerkhofs K, Mansouri-Noori F. La proteins couple use of sequence-specific and non-specific binding modes to engage RNA substrates. RNA Biol 2021; 18:168-177. [PMID: 30777481 PMCID: PMC7928037 DOI: 10.1080/15476286.2019.1582955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/05/2019] [Accepted: 02/05/2019] [Indexed: 12/31/2022] Open
Abstract
La shuttles between the nucleus and cytoplasm where it binds nascent RNA polymerase III (pol III) transcripts and mRNAs, respectively. La protects the 3' end of pol III transcribed RNA precursors, such as pre-tRNAs, through the use of a well-characterized UUU-3'OH binding mode. La proteins are also RNA chaperones, and La-dependent RNA chaperone activity is hypothesized to promote pre-tRNA maturation and translation at cellular and viral internal ribosome entry sites via binding sites distinct from those used for UUU-3'OH recognition. Since the publication of La-UUU-3'OH co-crystal structures, biochemical and genetic experiments have expanded our understanding of how La proteins use UUU-3'OH-independent binding modes to make sequence-independent contacts that can increase affinity for ligands and promote RNA remodeling. Other recent work has also expanded our understanding of how La binds mRNAs through contacts to the poly(A) tail. In this review, we focus on advances in the study of La protein-RNA complex surfaces beyond the description of the La-UUU-3'OH binding mode. We highlight recent advances in the functions of expected canonical nucleic acid interaction surfaces, a heightened appreciation of disordered C-terminal regions, and the nature of sequence-independent RNA determinants in La-RNA target binding. We further discuss how these RNA binding modes may have relevance to the function of the La-related proteins.
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Affiliation(s)
- Mark A. Bayfield
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Jyotsna Vinayak
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Kyra Kerkhofs
- Department of Biology, York University, Toronto, Ontario, Canada
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13
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RNA-Binding Protein La Mediates TGFβ-Induced Epithelial to Mesenchymal Transition and Cancer Stem Cell Properties. Cancers (Basel) 2021; 13:cancers13020343. [PMID: 33477794 PMCID: PMC7832410 DOI: 10.3390/cancers13020343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 01/06/2023] Open
Abstract
Simple Summary Reversible epithelial to mesenchymal transition (EMT) plays a key role in establishing a malignant phenotype by assuring cancer cell plasticity critical for cancer progression by allowing a small fraction of cancer cells to detach from primary lesions and outgrow at metastatic sites. Cancer cell plasticity is associated with cancer stem cell properties contributing to chemoresistance, metastasis, and poor clinical outcomes. Dysregulated RNA-binding proteins are key players in controlling the RNA metabolism, including mRNA processing, export, and translation, and have been implicated in cancer cell plasticity. In this study, we demonstrated that aberrantly expressed RNA-binding protein La is critical for transforming growth factor β-induced EMT and for gaining cancer stem cell properties. Understanding the function of aberrant RNA-binding protein expression in cancer cell plasticity reveals prospects for identifying novel therapeutic targets. Abstract Background: the aberrant overexpression of predominantly nuclear localizing RNA-binding protein (RBP) La contributes to proliferation, mobility, and chemoresistance of cancer cells and tumor growth in mice. Methods: studies included cancer tissue microarrays (TMAs) analyses, cancer tissue data mining, transforming growth factor β (TGFβ)-induced cancer cell plasticity studies, three dimensional sphere growth, epithelial to mesenchymal transition (EMT) assays, analysis of cancer stem cell (CSC) marker expression, and post-translational modification of cancer-associated La protein. Results: we demonstrated that significant overexpression of RBP La in lung and head and neck cancer tissue correlates with poor overall survival. Furthermore, small interfering RNA-mediated depletion of La reduced proliferation and migration of cancer cells, blocked TGFβ-induced EMT, and diminished both EMT and CSC marker expression. Rescue experiments with La wildtype but not RNA chaperone domain activity-defective La mutant increased the expression of those cancer progression markers, suggesting a critical role of La’s RNA chaperone activity in this process. La depletion in cancer cells also significantly decreased sphere growth in the presence of TGFβ. Interestingly, TGFβ treatment induced phosphorylation of La at threonine 389 (pLaT389) only in adherents but not in 3D growing cultures. Conclusion: our study suggests that the TGFβ/AKT/pLaT389 signaling pathway regulates cancer cell plasticity.
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14
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Kumar R, Poria DK, Ray PS. RNA-binding proteins La and HuR cooperatively modulate translation repression of PDCD4 mRNA. J Biol Chem 2021; 296:100154. [PMID: 33288677 PMCID: PMC7949077 DOI: 10.1074/jbc.ra120.014894] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/28/2022] Open
Abstract
Posttranscriptional regulation of gene expression plays a critical role in controlling the inflammatory response. An uncontrolled inflammatory response results in chronic inflammation, often leading to tumorigenesis. Programmed cell death 4 (PDCD4) is a proinflammatory tumor-suppressor gene which helps to prevent the transition from chronic inflammation to cancer. PDCD4 mRNA translation is regulated by an interplay between the oncogenic microRNA miR-21 and the RNA-binding protein (RBP) human antigen R (HuR) in response to lipopolysaccharide stimulation, but the role of other regulatory factors remains unknown. Here, we report that the RBP lupus antigen (La) interacts with the 3'-untranslated region of PDCD4 mRNA and prevents miR-21-mediated translation repression. While lipopolysaccharide causes nuclear-cytoplasmic translocation of HuR, it enhances cellular La expression. Remarkably, La and HuR were found to bind cooperatively to the PDCD4 mRNA and mitigate miR-21-mediated translation repression. The cooperative action of La and HuR reduced cell proliferation and enhanced apoptosis, reversing the pro-oncogenic function of miR-21. Together, these observations demonstrate a cooperative interplay between two RBPs, triggered differentially by the same stimulus, which exerts a synergistic effect on PDCD4 expression and thereby helps maintain a balance between inflammation and tumorigenesis.
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Affiliation(s)
- Ravi Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, India
| | - Dipak Kumar Poria
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, India
| | - Partho Sarothi Ray
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, India.
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15
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Kaliatsi EG, Argyriou AI, Bouras G, Apostolidi M, Konstantinidou P, Shaukat AN, Spyroulias GA, Stathopoulos C. Functional and Structural Aspects of La Protein Overexpression in Lung Cancer. J Mol Biol 2020; 432:166712. [PMID: 33197462 DOI: 10.1016/j.jmb.2020.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
La is an abundant phosphoprotein that protects polymerase III transcripts from 3'-5' exonucleolytic degradation and facilitates their folding. Consisting of the evolutionary conserved La motif (LAM) and two consecutive RNA Recognition Motifs (RRMs), La was also found to bind additional RNA transcripts or RNA domains like internal ribosome entry site (IRES), through sequence-independent binding modes which are poorly understood. Although it has been reported overexpressed in certain cancer types and depletion of its expression sensitizes cancer cells to certain chemotherapeutic agents, its role in cancer remains essentially uncharacterized. Herein, we study the effects of La overexpression in A549 lung adenocarcinoma cells, which leads to increased cell proliferation and motility. Expression profiling of several transcription and translation factors indicated that La overexpression leads to downregulation of global translation through hypophosphorylation of 4E-BPs and upregulation of IRES-mediated translation. Moreover, analysis of La localization after nutrition deprivation of the transfected cells showed a normal distribution in the nucleus and nucleoli. Although the RNA binding capacity of La has been primarily linked to the synergy between the conserved LAM and RRM1 domains which act as a module, we show that recombinant stand-alone LAM can specifically bind a pre-tRNA ligand, based on binding experiments combined with NMR analysis. We propose that LAM RNA binding properties could support the expanding and diverse RNA ligand repertoire of La, thus promoting its modulatory role, both under normal and pathogenic conditions like cancer.
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Affiliation(s)
- Eleni G Kaliatsi
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | | | - Georgios Bouras
- Department of Pharmacy, University of Patras, 26504 Patras, Greece
| | - Maria Apostolidi
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
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16
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Huang X, Tang J. Human La Protein: An RNA-Binding Protein Involved in Ovarian Cancer Development and Multidrug Resistance. Onco Targets Ther 2020; 13:10721-10727. [PMID: 33132701 PMCID: PMC7592153 DOI: 10.2147/ott.s269983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/04/2020] [Indexed: 12/18/2022] Open
Abstract
Multidrug resistance is the main cause of chemotherapy failure and death in patients with advanced ovarian cancer. Drug resistance is a problem that must be solved to improve the survival rate of patients with advanced ovarian cancer. The RNA-binding protein La and the La-related protein family are highly expressed in various malignant tumors, including ovarian cancer. This article reviews the mechanisms of La protein in tumorigenesis, development, and drug resistance. High La protein expression in tumor cells promotes tumor proliferation, invasion, and migration; disrupts cell cycle; and inhibits tumor cell apoptosis caused by chemotherapeutic drugs through various pathways, resulting in chemotherapy resistance in ovarian cancer. Further study of the role of La protein in ovarian cancer multidrug resistance may be conducive to the development of human La protein-specific inhibitors that suppress ovarian cancer drug resistance.
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Affiliation(s)
- Xuan Huang
- Department of Pharmacy, Obstetrics & Gynecology Hospital of Fudan University, Shanghai 200011, People's Republic of China
| | - Jing Tang
- Department of Pharmacy, Obstetrics & Gynecology Hospital of Fudan University, Shanghai 200011, People's Republic of China
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17
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Kang D, Lee Y, Lee JS. RNA-Binding Proteins in Cancer: Functional and Therapeutic Perspectives. Cancers (Basel) 2020; 12:cancers12092699. [PMID: 32967226 PMCID: PMC7563379 DOI: 10.3390/cancers12092699] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Simple Summary RNA-binding proteins (RBPs) play central roles in regulating posttranscriptional expression of genes. Many of them are known to be deregulated in a wide variety of cancers. Dysregulated RBPs influence the expression levels of target RNAs related to cancer phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and EMT/invasion/metastasis. Thus, understanding the molecular functions of RBPs and their roles in cancer-related phenotypes can lead to improved therapeutic strategies. Abstract RNA-binding proteins (RBPs) crucially regulate gene expression through post-transcriptional regulation, such as by modulating microRNA (miRNA) processing and the alternative splicing, alternative polyadenylation, subcellular localization, stability, and translation of RNAs. More than 1500 RBPs have been identified to date, and many of them are known to be deregulated in cancer. Alterations in the expression and localization of RBPs can influence the expression levels of oncogenes, tumor-suppressor genes, and genome stability-related genes. RBP-mediated gene regulation can lead to diverse cancer-related cellular phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and epithelial-mesenchymal transition (EMT)/invasion/metastasis. This regulation can also be associated with cancer prognosis. Thus, RBPs can be potential targets for the development of therapeutics for the cancer treatment. In this review, we describe the molecular functions of RBPs, their roles in cancer-related cellular phenotypes, and various approaches that may be used to target RBPs for cancer treatment.
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Affiliation(s)
- Donghee Kang
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
| | - Yerim Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
| | - Jae-Seon Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
- Correspondence: ; Tel.: +82-32-860-9832
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18
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Pan J, Tong S, Kong L, Zhu J, Tang J. La protein contributes to cells proliferation and migration and serves as a potential therapeutic target for hepatocellular carcinoma. Asia Pac J Clin Oncol 2020; 16:e228-e235. [PMID: 32780941 DOI: 10.1111/ajco.13370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 04/28/2020] [Indexed: 01/09/2023]
Abstract
AIM La protein is a multifunctional RNA-binding protein involved in RNA metabolism that has been reported to promote the growth of some solid tumors. However, potential role of La in hepatocellular carcinoma (HCC) has not been fully elucidated. This study aimed to investigate the expression of La and its function in HCC. METHODS Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis were conducted to detect the expression levels of La mRNA and protein in HCC cells and tissues. The proliferation capability of cells was clarified by Cell Counting Kit-8 and clone formation assays. Wound healing assay was carried out to assess cell migration ability. Related protein expressions were also analyzed by western blot. RESULTS Analysis of our clinical samples showed that La mRNA and protein expression of HCC tissues was higher than those of corresponding adjacent tissues, consistent with the result of microarray datasets from Oncomine database. La was also significantly overexpressed in eight HCC cells, compared with normal hepatocytes. According to in vitro experiments, we demonstrated that knockdown of La inhibited HCC cell proliferation and migration. CONCLUSIONS Our results revealed that La expression is elevated both at the RNA and protein levels in HCC. Highly expressed La significantly promotes tumorigenesis of HCC, suggesting that La may be a potential therapeutic target for the treatment of HCC.
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Affiliation(s)
- Jiaqian Pan
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Shuangmei Tong
- Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingjun Kong
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Jialei Zhu
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Jing Tang
- Department of Pharmacy, The Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
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19
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Abstract
RNA-binding proteins are important regulators of RNA metabolism and are of critical importance in all steps of the gene expression cascade. The role of aberrantly expressed RBPs in human disease is an exciting research field and the potential application of RBPs as a therapeutic target or a diagnostic marker represents a fast-growing area of research.Aberrant overexpression of the human RNA-binding protein La has been found in various cancer entities including lung, cervical, head and neck, and chronic myelogenous leukaemia. Cancer-associated La protein supports tumour-promoting processes such as proliferation, mobility, invasiveness and tumour growth. Moreover, the La protein maintains the survival of cancer cells by supporting an anti-apoptotic state that may cause resistance to chemotherapeutic therapy.The human La protein represents a multifunctional post-translationally modified RNA-binding protein with RNA chaperone activity that promotes processing of non-coding precursor RNAs but also stimulates the translation of selective messenger RNAs encoding tumour-promoting and anti-apoptotic factors. In our model, La facilitates the expression of those factors and helps cancer cells to cope with cellular stress. In contrast to oncogenes, able to initiate tumorigenesis, we postulate that the aberrantly elevated expression of the human La protein contributes to the non-oncogenic addiction of cancer cells. In this review, we summarize the current understanding about the implications of the RNA-binding protein La in cancer progression and therapeutic resistance. The concept of exploiting the RBP La as a cancer drug target will be discussed.
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Affiliation(s)
- Gunhild Sommer
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
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20
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Sommer G, Sendlmeier C, Heise T. Salt-Dependent Modulation of the RNA Chaperone Activity of RNA-Binding Protein La. Methods Mol Biol 2020; 2106:121-136. [PMID: 31889254 DOI: 10.1007/978-1-0716-0231-7_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It is well established that the RNA-binding protein La has RNA chaperone activity. Recent work suggests that the La protein has two distinct RNA chaperone domains (RCD-A and RCD-B) assisting structural changes in diverse groups of RNA molecules such as RNA polymerase III transcripts (e.g., pre-tRNA, U6 snRNA), cellular messenger, and viral RNAs. In this protocol we focus on the RNA chaperone domain RCD-B, which is located in the carboxy-terminal domain of La. It has been shown that this RNA chaperone domain assists structural changes in predicted RNA hairpins folded in the 5'-untranslated regions of cyclin D1 and Bcl2 mRNAs. Besides RNA helicases, which are implicated in melting RNA hairpin structures in an ATP-dependent manner, RNA chaperones fulfil a similar function in an ATP-independent manner. Aiming to study the RNA chaperon activity of La, we established a La-dependent molecular beacon-based RNA chaperone assay and systematically tested the various salt conditions. Herein we describe the assay format and design to study the salt dependency of RNA chaperones. This protocol can be easily adapted to test the RNA chaperone activity of other RNA-binding proteins and to optimize assay conditions.
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Affiliation(s)
- Gunhild Sommer
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany
| | - Christina Sendlmeier
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital of Regensburg, Regensburg, Germany.
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21
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Temoche-Diaz MM, Shurtleff MJ, Nottingham RM, Yao J, Fadadu RP, Lambowitz AM, Schekman R. Distinct mechanisms of microRNA sorting into cancer cell-derived extracellular vesicle subtypes. eLife 2019; 8:e47544. [PMID: 31436530 PMCID: PMC6728143 DOI: 10.7554/elife.47544] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) encompass a variety of vesicles secreted into the extracellular space. EVs have been implicated in promoting tumor metastasis, but the molecular composition of tumor-derived EV sub-types and the mechanisms by which molecules are sorted into EVs remain mostly unknown. We report the separation of two small EV sub-populations from a metastatic breast cancer cell line, with biochemical features consistent with different sub-cellular origins. These EV sub-types use different mechanisms of miRNA sorting (selective and non-selective), suggesting that sorting occurs via fundamentally distinct processes, possibly dependent on EV origin. Using biochemical and genetic tools, we identified the Lupus La protein as mediating sorting of selectively packaged miRNAs. We found that two motifs embedded in miR-122 are responsible for high-affinity binding to Lupus La and sorting into vesicles formed in a cell-free reaction. Thus, tumor cells can simultaneously deploy multiple EV species using distinct sorting mechanisms that may enable diverse functions in normal and cancer biology.
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Affiliation(s)
- Morayma M Temoche-Diaz
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Matthew J Shurtleff
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Ryan M Nottingham
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Jun Yao
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Raj P Fadadu
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Alan M Lambowitz
- Department of Molecular Biosciences, Institute for Cellular and Molecular BiologyUniversity of TexasAustinUnited States
| | - Randy Schekman
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
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22
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Vinayak J, Marrella SA, Hussain RH, Rozenfeld L, Solomon K, Bayfield MA. Human La binds mRNAs through contacts to the poly(A) tail. Nucleic Acids Res 2019; 46:4228-4240. [PMID: 29447394 PMCID: PMC5934636 DOI: 10.1093/nar/gky090] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 01/31/2018] [Indexed: 12/31/2022] Open
Abstract
In addition to a role in the processing of nascent RNA polymerase III transcripts, La proteins are also associated with promoting cap-independent translation from the internal ribosome entry sites of numerous cellular and viral coding RNAs. La binding to RNA polymerase III transcripts via their common UUU-3’OH motif is well characterized, but the mechanism of La binding to coding RNAs is poorly understood. Using electromobility shift assays and cross-linking immunoprecipitation, we show that in addition to a sequence specific UUU-3’OH binding mode, human La exhibits a sequence specific and length dependent poly(A) binding mode. We demonstrate that this poly(A) binding mode uses the canonical nucleic acid interaction winged helix face of the eponymous La motif, previously shown to be vacant during uridylate binding. We also show that cytoplasmic, but not nuclear La, engages poly(A) RNA in human cells, that La entry into polysomes utilizes the poly(A) binding mode, and that La promotion of translation from the cyclin D1 internal ribosome entry site occurs in competition with cytoplasmic poly(A) binding protein (PABP). Our data are consistent with human La functioning in translation through contacts to the poly(A) tail.
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Affiliation(s)
- Jyotsna Vinayak
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Stefano A Marrella
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Rawaa H Hussain
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Leonid Rozenfeld
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Karine Solomon
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
| | - Mark A Bayfield
- Department of Biology, York University, 4700 Keele St., Life Science Building #327E, Toronto, ON M3J 1P3, Canada
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23
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Mohibi S, Chen X, Zhang J. Cancer the'RBP'eutics-RNA-binding proteins as therapeutic targets for cancer. Pharmacol Ther 2019; 203:107390. [PMID: 31302171 DOI: 10.1016/j.pharmthera.2019.07.001] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/02/2019] [Indexed: 12/11/2022]
Abstract
RNA-binding proteins (RBPs) play a critical role in the regulation of various RNA processes, including splicing, cleavage and polyadenylation, transport, translation and degradation of coding RNAs, non-coding RNAs and microRNAs. Recent studies indicate that RBPs not only play an instrumental role in normal cellular processes but have also emerged as major players in the development and spread of cancer. Herein, we review the current knowledge about RNA binding proteins and their role in tumorigenesis as well as the potential to target RBPs for cancer therapeutics.
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Affiliation(s)
- Shakur Mohibi
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States.
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24
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Shan F, Mei S, Zhang J, Zhang X, Xu C, Liao S, Tu X. A telomerase subunit homolog La protein from
Trypanosoma brucei
plays an essential role in ribosomal biogenesis. FEBS J 2019; 286:3129-3147. [DOI: 10.1111/febs.14853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/23/2019] [Accepted: 04/13/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Fangzhen Shan
- Hefei National Laboratory for Physical Science at Microscale School of Life Science University of Science and Technology of China Hefei China
| | - Song Mei
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Kunming China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Science at Microscale School of Life Science University of Science and Technology of China Hefei China
| | | | - Chao Xu
- Hefei National Laboratory for Physical Science at Microscale School of Life Science University of Science and Technology of China Hefei China
| | - Shanhui Liao
- Hefei National Laboratory for Physical Science at Microscale School of Life Science University of Science and Technology of China Hefei China
| | - Xiaoming Tu
- Hefei National Laboratory for Physical Science at Microscale School of Life Science University of Science and Technology of China Hefei China
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Egiz M, Usui T, Ishibashi M, Zhang X, Shigeta S, Toyoshima M, Kitatani K, Yaegashi N. La-Related Protein 4 as a Suppressor for Motility of Ovarian Cancer Cells. TOHOKU J EXP MED 2019; 247:59-67. [PMID: 30686809 DOI: 10.1620/tjem.247.59] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The La-related proteins (LARPs) are a family of RNA binding proteins that control the degradation and stabilization of RNAs. As emerging research reveals the biology of each LARP, it is evident that LARPs are dysregulated in some types of cancer. Upregulation of cell motility potentiates the metastatic potential of ovarian cancer cells; however, the roles of LARPs in cell motility remain unknown. In the present study, we investigated the roles of LARPs in the progression of ovarian cancer using SKOV3 human ovarian cancer cells and a public database that integrates microarray-based gene expression data and clinical data. To explore the involvement of LARPs in the cell motility, we performed RNA interference screening for LARP mRNAs in SKOV3 cells. The screening identified LARP4 as a potential suppressor of the formation of lamellipodia. Conversely, enforced expression of LARP4 suppressed the formation of lamellipodia. Moreover, cell migration was significantly increased in LARP4-depleted SKOV3 cells. Mechanistically, LARP4 depletion was associated with the decrease in RhoA protein expression. These results suggest that LARP4 may limit RhoA-dependent cell motility. In a mouse xenograft model with SKOV3 cells, LARP4 depletion potentiated peritoneal metastasis. Upon analysis of a public database of patients with ovarian cancer, the LARP4 mRNA-high expression group (n = 166) showed longer overall survival compared with the LARP4 mRNA-low expression group (n = 489), implying a positive correlation of LARP4 mRNA levels in ovarian cancer tissues with patient prognosis. Taken together, we propose that LARP4 could suppress motility and metastatic potential of ovarian cancer cells.
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Affiliation(s)
- Mahy Egiz
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
- Department of Obstetrics and Gynecology, Menoufia University Graduate School of Medicine
| | - Toshinori Usui
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
| | - Masumi Ishibashi
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
| | - Xuewei Zhang
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
| | - Shogo Shigeta
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
| | - Masafumi Toyoshima
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
| | - Kazuyuki Kitatani
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
- Tohoku Medical Megabank Organization, Tohoku University
- Laboratory of Immunopharmacology, Faculty of Pharmaceutical Sciences, Setsunan University
| | - Nobuo Yaegashi
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Tohoku University
- Tohoku Medical Megabank Organization, Tohoku University
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Marrella SA, Brown KA, Mansouri-Noori F, Porat J, Wilson DJ, Bayfield MA. An interdomain bridge influences RNA binding of the human La protein. J Biol Chem 2018; 294:1529-1540. [PMID: 30530494 DOI: 10.1074/jbc.ra118.003995] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/20/2018] [Indexed: 12/15/2022] Open
Abstract
La proteins are RNA chaperones that perform various functions depending on distinct RNA-binding modes and their subcellular localization. In the nucleus, they help process UUU-3'OH-tailed nascent RNA polymerase III transcripts, such as pre-tRNAs, whereas in the cytoplasm they contribute to translation of poly(A)-tailed mRNAs. La accumulation in the nucleus and cytoplasm is controlled by several trafficking elements, including a canonical nuclear localization signal in the extreme C terminus and a nuclear retention element (NRE) in the RNA recognition motif 2 (RRM2) domain. Previous findings indicate that cytoplasmic export of La due to mutation of the NRE can be suppressed by mutations in RRM1, but the mechanism by which the RRM1 and RRM2 domains functionally cooperate is poorly understood. In this work, we use electromobility shift assays (EMSA) to show that mutations in the NRE and RRM1 affect binding of human La to pre-tRNAs but not UUU-3'OH or poly(A) sequences, and we present compensatory mutagenesis data supporting a direct interaction between the RRM1 and RRM2 domains. Moreover, we use collision-induced unfolding and time-resolved hydrogen-deuterium exchange MS analyses to study the conformational dynamics that occur when this interaction is intact or disrupted. Our results suggest that the intracellular distribution of La may be linked to its RNA-binding modes and provide the first evidence for a direct protein-protein interdomain interaction in La proteins.
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Affiliation(s)
- Stefano A Marrella
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Kerene A Brown
- Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada; Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada; Research in Mass Spectrometry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Farnaz Mansouri-Noori
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jennifer Porat
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Derek J Wilson
- Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada; Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada; Research in Mass Spectrometry, York University, Toronto, Ontario M3J 1P3, Canada.
| | - Mark A Bayfield
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada; Centres for Research in Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada.
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Staudacher AH, Li Y, Liapis V, Hou JJC, Chin D, Dolezal O, Adams TE, van Berkel PH, Brown MP. APOMAB Antibody–Drug Conjugates Targeting Dead Tumor Cells are Effective In Vivo. Mol Cancer Ther 2018; 18:335-345. [DOI: 10.1158/1535-7163.mct-18-0842] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/05/2018] [Accepted: 11/05/2018] [Indexed: 11/16/2022]
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The La protein counteracts cisplatin-induced cell death by stimulating protein synthesis of anti-apoptotic factor Bcl2. Oncotarget 2018; 7:29664-76. [PMID: 27105491 PMCID: PMC5045424 DOI: 10.18632/oncotarget.8819] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/28/2016] [Indexed: 02/06/2023] Open
Abstract
Up-regulation of anti-apoptotic factors is a critical mechanism of cancer cell resistance and often counteracts the success of chemotherapeutic treatment. Herein, we identified the cancer-associated RNA-binding protein La as novel factor contributing to cisplatin resistance. Our data demonstrate that depletion of the RNA-binding protein La in head and neck squamous cell carcinoma cells (HNSCC) increases the sensitivity toward cisplatin-induced cell death paralleled by reduced expression of the anti-apoptotic factor Bcl2. Furthermore, it is shown that transient expression of Bcl2 in La-depleted cells protects against cisplatin-induced cell death. By dissecting the underlying mechanism we report herein, that the La protein is required for Bcl2 protein synthesis in cisplatin-treated cells. The RNA chaperone La binds in close proximity to the authentic translation start site and unwinds a secondary structure embedding the authentic AUG. Altogether, our data support a novel model, whereby cancer-associated La protein contributes to cisplatin resistance by stimulating the translation of anti-apoptotic factor Bcl2 in HNSCC cells.
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SUMO Modification of the RNA-Binding Protein La Regulates Cell Proliferation and STAT3 Protein Stability. Mol Cell Biol 2017; 38:MCB.00129-17. [PMID: 29084811 DOI: 10.1128/mcb.00129-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/19/2017] [Indexed: 01/06/2023] Open
Abstract
The cancer-associated RNA-binding protein La is posttranslationally modified by phosphorylation and sumoylation. Sumoylation of La regulates not only the trafficking of La in neuronal axons but also its association with specific mRNAs. Depletion of La in various types of cancer cell lines impairs cell proliferation; however, the molecular mechanism whereby La supports cell proliferation is not clearly understood. In this study, we address the question of whether sumoylation of La contributes to cell proliferation of HEK293 cells. We show that HEK293 cells stably expressing green fluorescent protein (GFP)-tagged wild-type La (GFP-LaWT) grow faster than cells expressing a sumoylation-deficient mutant La (GFP-LaSD), suggesting a proproliferative function of La in HEK293 cells. Further, we found that STAT3 protein levels were reduced in GFP-LaSD cells due to an increase in STAT3 ubiquitination and that overexpression of STAT3 partially restored cell proliferation. Finally, we present RNA sequencing data from RNA immunoprecipitations (RIPs) and report that mRNAs associated with the cell cycle and ubiquitination are preferentially bound by GFP-LaWT and are less enriched in GFP-LaSD RIPs. Taken together, results of our study support a novel mechanism whereby sumoylation of La promotes cell proliferation by averting ubiquitination-mediated degradation of the STAT3 protein.
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Maraia RJ, Mattijssen S, Cruz-Gallardo I, Conte MR. The La and related RNA-binding proteins (LARPs): structures, functions, and evolving perspectives. WILEY INTERDISCIPLINARY REVIEWS. RNA 2017; 8:10.1002/wrna.1430. [PMID: 28782243 PMCID: PMC5647580 DOI: 10.1002/wrna.1430] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 01/02/2023]
Abstract
La was first identified as a polypeptide component of ribonucleic protein complexes targeted by antibodies in autoimmune patients and is now known to be a eukaryote cell-ubiquitous protein. Structure and function studies have shown that La binds to a common terminal motif, UUU-3'-OH, of nascent RNA polymerase III (RNAP III) transcripts and protects them from exonucleolytic decay. For precursor-tRNAs, the most diverse and abundant of these transcripts, La also functions as an RNA chaperone that helps to prevent their misfolding. Related to this, we review evidence that suggests that La and its link to RNAP III were significant in the great expansions of the tRNAomes that occurred in eukaryotes. Four families of La-related proteins (LARPs) emerged during eukaryotic evolution with specialized functions. We provide an overview of the high-resolution structural biology of La and LARPs. LARP7 family members most closely resemble La but function with a single RNAP III nuclear transcript, 7SK, or telomerase RNA. A cytoplasmic isoform of La protein as well as LARPs 6, 4, and 1 function in mRNA metabolism and translation in distinct but similar ways, sometimes with the poly(A)-binding protein, and in some cases by direct binding to poly(A)-RNA. New structures of LARP domains, some complexed with RNA, provide novel insights into the functional versatility of these proteins. We also consider LARPs in relation to ancestral La protein and potential retention of links to specific RNA-related pathways. One such link may be tRNA surveillance and codon usage by LARP-associated mRNAs. WIREs RNA 2017, 8:e1430. doi: 10.1002/wrna.1430 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Richard J. Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD USA
| | - Sandy Mattijssen
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Isabel Cruz-Gallardo
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
| | - Maria R. Conte
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
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Shang A, Lu WY, Yang M, Zhou C, Zhang H, Cai ZX, Wang WW, Wang WX, Wu GQ. miR-9 induces cell arrest and apoptosis of oral squamous cell carcinoma via CDK 4/6 pathway. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 46:1754-1762. [PMID: 29073835 DOI: 10.1080/21691401.2017.1391825] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Oral cancer remains a major public concern with considerable socioeconomic impact in the world, especially in southeast Asia. Despite substantial advancements have been made in treating oral cancer, the five-year survival rate for OSCC remained undesirable, and 35-55% patients developed recurrence within two years even with multimodality therapeutic strategies. Hence, identification of novel biomarkers for diagnosis and evaluating clinical outcome is of vital importance. MicroRNAs are 22-24 nt non-coding RNAs that could bind to 3' UTR of target mRNAs, thereby inducing degradation of mRNA or inhibiting translation. Due to its implication in regulation of post-transcriptional processes, the role of miRNAs in malignancies has been extensively studied, among which the discovery of functional miR-9 in oral squamous cell carcinoma (OSCC) remained to be elucidated. We first demonstrated that miR-9 was down-regulated in 21 OSCC patients, and we further found that forced expression of miR-9 could result in deterred cell proliferation and decreased ability to migrate and form colonies. Flow cytometry displayed cell-cycle arrested at G0/G1 phase. We next used Targetscan to predict target genes of miR-9. CDK6, a protein highly implicated in cell cycle control, was chosen for verification. Down-regulation of CDK6 and Cyclin D1 in Tca8113 transfected with miR-9 mimics indicate that the complex formed by both proteins may be the effector of the antiproliferative function of miR-9 in OSCCs. Considering small molecules are developed to target CDK4/6, our finding may provide valuable scientific evidence for research and development of therapies and diagnostic methodology in OSCCs.
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Affiliation(s)
- Anquan Shang
- a Department of Laboratory Medicine, , Tongji Hospital of Tongji University , Shanghai , China.,b Department of Laboratory Medicine , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Wen-Ying Lu
- b Department of Laboratory Medicine , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Man Yang
- c Department of Laboratory Medicine , Yancheng TCM Hospital Affiliated to Nanjing University of Chinese Medicine , Yancheng , Jiangsu , China.,d School of Biology & Basic Medical Sciences , Medical College of Soochow University , Suzhou , Jiangsu , China
| | - Cheng Zhou
- b Department of Laboratory Medicine , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Hong Zhang
- b Department of Laboratory Medicine , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Zheng-Xin Cai
- b Department of Laboratory Medicine , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Wei-Wei Wang
- e Department of Pathology , The First People's Hospital of Yancheng City , Yancheng , Jiangsu , China.,f Department of Pathology , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Wan-Xiang Wang
- g Department of Laboratory Medicine , The First People's Hospital of Yancheng City , Yancheng , Jiangsu , China
| | - Gui-Qi Wu
- h Department of General Surgery , The Sixth People's Hospital of Yancheng City , Yancheng , Jiangsu , China
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32
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Pan J, Tong S, Tang J. Alteration of microRNA profiles by a novel inhibitor of human La protein in HBV-transformed human hepatoma cells. J Med Virol 2017; 90:255-262. [PMID: 28885699 PMCID: PMC5763324 DOI: 10.1002/jmv.24941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/23/2017] [Indexed: 12/22/2022]
Abstract
A pyrazolopyridine HBSC11 was previously identified as a novel inhibitor of human La protein with anti‐hepatitis B virus (HBV) activity. However, the underlying mechanism(s) of HBV inhibition by HBSC11 remains unclear. This study aimed to examine the regulation of microRNA (miRNA) by HBSC11 in HBV‐transformed human hepatoma HepG2.2.15 cells using microarray and quantitative real‐time PCR. Target genes of the differentially expressed miRNAs were predicted and subjected to bioinformatics analysis. Results showed that HBSC11 significantly upregulated the expression of miR‐3912‐5p, miR‐6793‐5p, and miR‐7159‐5p in HepG2.2.15 cells. Target genes of the three miRNAs were mainly involved in the regulation of nucleic acid‐templated transcription, negative regulation of gene expression, nucleic acid binding transcription factor activity and regulation of phosphorylation. In addition, target genes were enriched in certain regulatory pathways related to HBV infection and HBV‐associated disease progression, such as the transforming growth factor (TGF)‐β, Wnt, and p53 signaling. Our study demonstrates the involvement of miR‐3912‐5p, miR‐6793‐5p, and miR‐7159‐5p and the potential modulation of specific pathways (TGF‐β, Wnt, and p53 signaling) in HBSC11‐mediated inhibition of HBV replication. This study provides insight into the molecular mechanism of the action of HBSC11 against HBV infection and will support the development of antiviral drugs targeting La protein.
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Affiliation(s)
- Jiaqian Pan
- Department of Clinical Pharmacy, Shanghai General Hospital of Nanjing Medical University, Shanghai, China.,Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuangmei Tong
- Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Tang
- Department of Clinical Pharmacy, Shanghai General Hospital of Nanjing Medical University, Shanghai, China.,Department of Clinical Pharmacy, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Pereira B, Billaud M, Almeida R. RNA-Binding Proteins in Cancer: Old Players and New Actors. Trends Cancer 2017; 3:506-528. [PMID: 28718405 DOI: 10.1016/j.trecan.2017.05.003] [Citation(s) in RCA: 459] [Impact Index Per Article: 65.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/15/2022]
Abstract
RNA-binding proteins (RBPs) are key players in post-transcriptional events. The combination of versatility of their RNA-binding domains with structural flexibility enables RBPs to control the metabolism of a large array of transcripts. Perturbations in RBP-RNA networks activity have been causally associated with cancer development, but the rational framework describing these contributions remains fragmented. We review here the evidence that RBPs modulate multiple cancer traits, emphasize their functional diversity, and assess future trends in the study of RBPs in cancer.
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Affiliation(s)
- Bruno Pereira
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal.
| | - Marc Billaud
- Clinical and Experimental Model of Lymphomagenesis, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1052, Centre National de la Recherche Scientifique (CNRS) Unité 5286, Centre Léon Bérard, Université Claude Bernard Lyon 1, Centre de Recherche en Cancérologie de Lyon, Lyon, France
| | - Raquel Almeida
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal; Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; Biology Department, Faculty of Sciences of the University of Porto, 4169-007 Porto, Portugal
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Blewett NH, Iben JR, Gaidamakov S, Maraia RJ. La Deletion from Mouse Brain Alters Pre-tRNA Metabolism and Accumulation of Pre-5.8S rRNA, with Neuron Death and Reactive Astrocytosis. Mol Cell Biol 2017; 37:e00588-16. [PMID: 28223366 PMCID: PMC5477551 DOI: 10.1128/mcb.00588-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/01/2016] [Accepted: 02/06/2017] [Indexed: 12/20/2022] Open
Abstract
Human La antigen (Sjögren's syndrome antigen B [SSB]) is an abundant multifunctional RNA-binding protein. In the nucleoplasm, La binds to and protects from 3' exonucleases, the ends of precursor tRNAs, and other transcripts synthesized by RNA polymerase III and facilitates their maturation, while a nucleolar isoform has been implicated in rRNA biogenesis by multiple independent lines of evidence. We showed previously that conditional La knockout (La cKO) from mouse cortex neurons results in defective tRNA processing, although the pathway(s) involved in neuronal loss thereafter was unknown. Here, we demonstrate that La is stably associated with a spliced pre-tRNA intermediate. Microscopic evidence of aberrant nuclear accumulation of 5.8S rRNA in La cKO is supported by a 10-fold increase in a pre-5.8S rRNA intermediate. To identify pathways involved in subsequent neurodegeneration and loss of brain mass in the cKO cortex, we employed mRNA sequencing (mRNA-Seq), immunohistochemistry, and other approaches. This revealed robust enrichment of immune and astrocyte reactivity in La cKO cortex. Immunohistochemistry, including temporal analyses, demonstrated neurodegeneration, followed by astrocyte invasion associated with immune response and decreasing cKO cortex size over time. Thus, deletion of La from postmitotic neurons results in defective pre-tRNA and pre-rRNA processing and progressive neurodegeneration with loss of cortical brain mass.
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Affiliation(s)
- Nathan H Blewett
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - James R Iben
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - Sergei Gaidamakov
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland, USA
| | - Richard J Maraia
- Commissioned Corps, U.S. Public Health Service, Rockville, Maryland, USA
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Sommer G, Fedarovich A, Kota V, Rodriguez R, Smith CD, Heise T. Applying a high-throughput fluorescence polarization assay for the discovery of chemical probes blocking La:RNA interactions in vitro and in cells. PLoS One 2017; 12:e0173246. [PMID: 28291789 PMCID: PMC5349447 DOI: 10.1371/journal.pone.0173246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/18/2017] [Indexed: 12/14/2022] Open
Abstract
The RNA-binding protein La is overexpressed in a number of tumor tissues and is thought to support tumorigenesis by binding to and facilitating the expression of mRNAs encoding tumor-promoting and anti-apoptotic factors. Hence, small molecules able to block the binding of La to specific RNAs could have a therapeutic impact by reducing the expression of tumor-promoting and anti-apoptotic factors. Toward this novel therapeutic strategy, we aimed to develop a high-throughput fluorescence polarization assay to screen small compound libraries for molecules blocking the binding of La to an RNA element derived from cyclin D1 mRNA. Herein, we make use of a robust fluorescence polarization assay and the validation of primary hits by electrophoretic mobility shift assays. We showed recently that La protects cells against cisplatin treatment by stimulating the protein synthesis of the anti-apoptotic factor Bcl2. Here, we show by RNA immunoprecipitation experiments that one small compound specifically impairs the association of La with Bcl2 mRNA in cells and sensitizes cells for cipslatin-induced cell death. In summary, we report the application of a high-throughput fluorescence polarization assay to identify small compounds that impair the binding of La to target RNAs in vitro and in cells.
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Affiliation(s)
- Gunhild Sommer
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Alena Fedarovich
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Venkatesh Kota
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Reycel Rodriguez
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Charles D. Smith
- Department of Pharmaceutical and Biomedical Sciences, 173 Ashley Avenue, Charleston, SC, United States of America
| | - Tilman Heise
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, 173 Ashley Avenue, Charleston, SC, United States of America
- * E-mail:
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Brown KA, Sharifi S, Hussain R, Donaldson L, Bayfield MA, Wilson DJ. Distinct Dynamic Modes Enable the Engagement of Dissimilar Ligands in a Promiscuous Atypical RNA Recognition Motif. Biochemistry 2016; 55:7141-7150. [PMID: 27959512 DOI: 10.1021/acs.biochem.6b00995] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conformational dynamics play a critical role in ligand binding, often conferring divergent activities and specificities even in species with highly similar ground-state structures. Here, we employ time-resolved electrospray ionization hydrogen-deuterium exchange (TRESI-HDX) to characterize the changes in dynamics that accompany oligonucleotide binding in the atypical RNA recognition motif (RRM2) in the C-terminal domain (CTD) of human La protein. Using this approach, which is uniquely capable of probing changes in the structure and dynamics of weakly ordered regions of proteins, we reveal that binding of RRM2 to a model 23-mer single-stranded RNA and binding of RRM2 to structured IRES domain IV of the hepatitis C viral (HCV) RNA are driven by fundamentally different dynamic processes. In particular, binding of the single-stranded RNA induces helical "unwinding" in a region of the CTD previously hypothesized to play an important role in La and La-related protein-associated RNA remodeling, while the same region becomes less dynamic upon engagement with the double-stranded HCV RNA. Binding of double-stranded RNA also involves less penetration into the RRM2 binding pocket and more engagement with the unstructured C-terminus of the La CTD. The complementarity between TRESI-HDX and Δδ nuclear magnetic resonance measurements for ligand binding analysis is also explored.
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Affiliation(s)
- Kerene A Brown
- Department of Chemistry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Mass Spectrometry, York University , Toronto, ON M3J 1P3, Canada
| | - Samel Sharifi
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Rawaa Hussain
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Logan Donaldson
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
| | - Mark A Bayfield
- Department of Biology, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Biomolecular Interactions, York University , Toronto, ON M3J 1P3, Canada
| | - Derek J Wilson
- Department of Chemistry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Mass Spectrometry, York University , Toronto, ON M3J 1P3, Canada
- Centre for Research in Biomolecular Interactions, York University , Toronto, ON M3J 1P3, Canada
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Seetharaman S, Flemyng E, Shen J, Conte MR, Ridley AJ. The RNA-binding protein LARP4 regulates cancer cell migration and invasion. Cytoskeleton (Hoboken) 2016; 73:680-690. [PMID: 27615744 PMCID: PMC5111583 DOI: 10.1002/cm.21336] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 01/07/2023]
Abstract
LARP4 is a La-related RNA-binding protein implicated in regulating mRNA translation, which interacts with poly(A)-binding protein (PABP). We previously identified LARP4 in an RNAi screen as one of several genes that regulate the shape of PC3 prostate cancer cells. Here we show that LARP4 depletion induces cell elongation in PC3 cells and MDA-MB-231 breast cancer cells. LARP4 depletion increases cell migration and invasion, as well as inducing invasive cell protrusions in 3D Matrigel. Conversely, LARP4 over-expression reduces cell elongation and increases cell circularity. LARP4 mutations are found in a variety of cancers. Introduction of some of these cancer-associated mutations, including a truncation mutant, into LARP4 enhances its effects on cell morphology. The truncation mutant shows enhanced interaction with PABP. We propose that LARP4 inhibits migration and invasion of cancer cells, and that some cancer-associated mutations stimulate these effects of LARP4. © 2016 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Shailaja Seetharaman
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Ella Flemyng
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Jiazhen Shen
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Maria R. Conte
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
| | - Anne J. Ridley
- Randall Division of Cell and Molecular BiophysicsKing's College LondonNew Hunt's House, Guy's CampusLondonSE1 1ULUnited Kingdom
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Kota V, Sommer G, Durette C, Thibault P, van Niekerk EA, Twiss JL, Heise T. SUMO-Modification of the La Protein Facilitates Binding to mRNA In Vitro and in Cells. PLoS One 2016; 11:e0156365. [PMID: 27224031 PMCID: PMC4880191 DOI: 10.1371/journal.pone.0156365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/12/2016] [Indexed: 02/05/2023] Open
Abstract
The RNA-binding protein La is involved in several aspects of RNA metabolism including the translational regulation of mRNAs and processing of pre-tRNAs. Besides its well-described phosphorylation by Casein kinase 2, the La protein is also posttranslationally modified by the Small Ubiquitin-like MOdifier (SUMO), but the functional outcome of this modification has not been defined. The objective of this study was to test whether sumoylation changes the RNA-binding activity of La. Therefore, we established an in vitro sumoylation assay for recombinant human La and analyzed its RNA-binding activity by electrophoretic mobility shift assays. We identified two novel SUMO-acceptor sites within the La protein located between the RNA recognition motif 1 and 2 and we demonstrate for the first time that sumoylation facilitates the RNA-binding of La to small RNA oligonucleotides representing the oligopyrimidine tract (TOP) elements from the 5' untranslated regions (UTR) of mRNAs encoding ribosomal protein L22 and L37 and to a longer RNA element from the 5' UTR of cyclin D1 (CCND1) mRNA in vitro. Furthermore, we show by RNA immunoprecipitation experiments that a La mutant deficient in sumoylation has impaired RNA-binding activity in cells. These data suggest that modulating the RNA-binding activity of La by sumoylation has important consequences on its functionality.
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Affiliation(s)
- Venkatesh Kota
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
| | - Gunhild Sommer
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
| | - Chantal Durette
- Institute of Research in Immunology and Cancer University de Montreal, Station Centre-ville, Montreal, Canada
| | - Pierre Thibault
- Institute of Research in Immunology and Cancer University de Montreal, Station Centre-ville, Montreal, Canada
| | - Erna A. van Niekerk
- Department of Neurosciences-0626, University of California, San Diego, La Jolla, California, United States of America
| | - Jeffery L. Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Tilman Heise
- Medical University of South Carolina, Department of Biochemistry & Molecular Biology, Charleston, South Carolina, United States of America
- * E-mail:
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Hopkins TG, Mura M, Al-Ashtal HA, Lahr RM, Abd-Latip N, Sweeney K, Lu H, Weir J, El-Bahrawy M, Steel JH, Ghaem-Maghami S, Aboagye EO, Berman AJ, Blagden SP. The RNA-binding protein LARP1 is a post-transcriptional regulator of survival and tumorigenesis in ovarian cancer. Nucleic Acids Res 2016; 44:1227-46. [PMID: 26717985 PMCID: PMC4756840 DOI: 10.1093/nar/gkv1515] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 12/12/2015] [Accepted: 12/17/2015] [Indexed: 11/25/2022] Open
Abstract
RNA-binding proteins (RBPs) are increasingly identified as post-transcriptional drivers of cancer progression. The RBP LARP1 is an mRNA stability regulator, and elevated expression of the protein in hepatocellular and lung cancers is correlated with adverse prognosis. LARP1 associates with an mRNA interactome that is enriched for oncogenic transcripts. Here we explore the role of LARP1 in epithelial ovarian cancer, a disease characterized by the rapid acquisition of resistance to chemotherapy through the induction of pro-survival signalling. We show, using ovarian cell lines and xenografts, that LARP1 is required for cancer cell survival and chemotherapy resistance. LARP1 promotes tumour formation in vivo and maintains cancer stem cell-like populations. Using transcriptomic analysis following LARP1 knockdown, cross-referenced against the LARP1 interactome, we identify BCL2 and BIK as LARP1 mRNA targets. We demonstrate that, through an interaction with the 3' untranslated regions (3' UTRs) of BCL2 and BIK, LARP1 stabilizes BCL2 but destabilizes BIK with the net effect of resisting apoptosis. Together, our data indicate that by differentially regulating the stability of a selection of mRNAs, LARP1 promotes ovarian cancer progression and chemotherapy resistance.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Autoantigens/genetics
- Autoantigens/metabolism
- Blotting, Western
- Carcinogenesis/genetics
- Carcinogenesis/metabolism
- Cell Line, Tumor
- Cell Survival/drug effects
- Cell Survival/genetics
- Disease Progression
- Drug Resistance, Neoplasm/genetics
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/genetics
- HeLa Cells
- Humans
- Interleukin Receptor Common gamma Subunit/deficiency
- Interleukin Receptor Common gamma Subunit/genetics
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Microscopy, Confocal
- Ovarian Neoplasms/genetics
- Ovarian Neoplasms/metabolism
- Ovarian Neoplasms/pathology
- Protein Binding
- RNA Interference
- Reverse Transcriptase Polymerase Chain Reaction
- Ribonucleoproteins/genetics
- Ribonucleoproteins/metabolism
- Survival Analysis
- Transplantation, Heterologous
- SS-B Antigen
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Affiliation(s)
- Thomas G Hopkins
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Manuela Mura
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Hiba A Al-Ashtal
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Roni M Lahr
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Normala Abd-Latip
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Katrina Sweeney
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Haonan Lu
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Justin Weir
- Department of Histopathology, Imperial College Healthcare NHS Trust, London W12 0NN, UK
| | - Mona El-Bahrawy
- Department of Histopathology, Imperial College Healthcare NHS Trust, London W12 0NN, UK
| | - Jennifer H Steel
- Imperial College Experimental Cancer Medicine Centre, Division of Cancer, Imperial College Academic Health Science Centre, London W12 0NN, UK
| | - Sadaf Ghaem-Maghami
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK
| | - Eric O Aboagye
- Comprehensive Cancer Imaging Centre, Imperial College, Du Cane Road, London W12 0NN, UK
| | - Andrea J Berman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Sarah P Blagden
- Ovarian Cancer Action Research Centre, Institute of Reproductive and Developmental Biology, Imperial College, London W12 0HS, UK Department of Oncology, University of Oxford, Old Road, Oxford OX3 7LE, UK
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40
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Stavraka C, Blagden S. The La-Related Proteins, a Family with Connections to Cancer. Biomolecules 2015; 5:2701-22. [PMID: 26501340 PMCID: PMC4693254 DOI: 10.3390/biom5042701] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/21/2015] [Accepted: 10/07/2015] [Indexed: 01/09/2023] Open
Abstract
The evolutionarily-conserved La-related protein (LARP) family currently comprises Genuine La, LARP1, LARP1b, LARP4, LARP4b, LARP6 and LARP7. Emerging evidence suggests each LARP has a distinct role in transcription and/or mRNA translation that is attributable to subtle sequence variations within their La modules and specific C-terminal domains. As emerging research uncovers the function of each LARP, it is evident that La, LARP1, LARP6, LARP7 and possibly LARP4a and 4b are dysregulated in cancer. Of these, LARP1 is the first to be demonstrated to drive oncogenesis. Here, we review the role of each LARP and the evidence linking it to malignancy. We discuss a future strategy of targeting members of this protein family as cancer therapy.
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Affiliation(s)
- Chara Stavraka
- Ovarian Cancer Research Centre, Institute for Reproductive and Developmental Biology, Imperial College, Du Cane Road, London W12 0HS, UK.
| | - Sarah Blagden
- Ovarian Cancer Research Centre, Institute for Reproductive and Developmental Biology, Imperial College, Du Cane Road, London W12 0HS, UK.
- Department of Oncology, University of Oxford, Churchill Hospital, Old Road, Oxford OX3 7LE, UK.
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41
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Mura M, Hopkins TG, Michael T, Abd-Latip N, Weir J, Aboagye E, Mauri F, Jameson C, Sturge J, Gabra H, Bushell M, Willis AE, Curry E, Blagden SP. LARP1 post-transcriptionally regulates mTOR and contributes to cancer progression. Oncogene 2015; 34:5025-36. [PMID: 25531318 PMCID: PMC4430325 DOI: 10.1038/onc.2014.428] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 09/20/2014] [Accepted: 10/21/2014] [Indexed: 12/24/2022]
Abstract
RNA-binding proteins (RBPs) bind to and post-transcriptionally regulate the stability of mRNAs. La-related protein 1 (LARP1) is a conserved RBP that interacts with poly-A-binding protein and is known to regulate 5'-terminal oligopyrimidine tract (TOP) mRNA translation. Here, we show that LARP1 is complexed to 3000 mRNAs enriched for cancer pathways. A prominent member of the LARP1 interactome is mTOR whose mRNA transcript is stabilized by LARP1. At a functional level, we show that LARP1 promotes cell migration, invasion, anchorage-independent growth and in vivo tumorigenesis. Furthermore, we show that LARP1 expression is elevated in epithelial cancers such as cervical and non-small cell lung cancers, where its expression correlates with disease progression and adverse prognosis, respectively. We therefore conclude that, through the post-transcriptional regulation of genes such as mTOR within cancer pathways, LARP1 contributes to cancer progression.
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Affiliation(s)
- M Mura
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - T G Hopkins
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - T Michael
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - N Abd-Latip
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - J Weir
- Department of Cellular Pathology, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, UK
| | - E Aboagye
- Division of Cancer, Department of Surgery and Cancer, Cancer Research UK Laboratories, Imperial College London, Hammersmith Campus, London, UK
| | - F Mauri
- Department of Histopathology, Centre for Pathology, Imperial College London, Hammersmith Campus, London, UK
| | - C Jameson
- Department of Histopathology, University College Hospital, London, UK
| | - J Sturge
- Division of Cancer, Department of Surgery and Cancer, Cancer Research UK Laboratories, Imperial College London, Hammersmith Campus, London, UK
- School of Biological, Biomedical & Environmental Sciences, The Allam Building, University of Hull, Hull, UK
| | - H Gabra
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - M Bushell
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - A E Willis
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - E Curry
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
| | - S P Blagden
- Division of Cancer, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London, Hammersmith Campus, London, UK
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42
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Kuehnert J, Sommer G, Zierk AW, Fedarovich A, Brock A, Fedarovich D, Heise T. Novel RNA chaperone domain of RNA-binding protein La is regulated by AKT phosphorylation. Nucleic Acids Res 2015; 43:581-94. [PMID: 25520193 PMCID: PMC4288197 DOI: 10.1093/nar/gku1309] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 01/13/2023] Open
Abstract
The cellular function of the cancer-associated RNA-binding protein La has been linked to translation of viral and cellular mRNAs. Recently, we have shown that the human La protein stimulates IRES-mediated translation of the cooperative oncogene CCND1 in cervical cancer cells. However, there is little known about the underlying molecular mechanism by which La stimulates CCND1 IRES-mediated translation, and we propose that its RNA chaperone activity is required. Herein, we show that La binds close to the CCND1 start codon and demonstrate that La's RNA chaperone activity can change the folding of its binding site. We map the RNA chaperone domain (RCD) within the C-terminal region of La in close proximity to a novel AKT phosphorylation site (T389). Phosphorylation at T389 by AKT-1 strongly impairs its RNA chaperone activity. Furthermore, we demonstrate that the RCD as well as T389 is required to stimulate CCND1 IRES-mediated translation in cells. In summary, we provide a model whereby a novel interplay between RNA-binding, RNA chaperoning and AKT phosphorylation of La protein regulates CCND1 IRES-mediated translation.
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Affiliation(s)
- Julia Kuehnert
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Gunhild Sommer
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Avery W Zierk
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Alena Fedarovich
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Alexander Brock
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Dzmitry Fedarovich
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Tilman Heise
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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43
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Vanharanta S, Marney CB, Shu W, Valiente M, Zou Y, Mele A, Darnell RB, Massagué J. Loss of the multifunctional RNA-binding protein RBM47 as a source of selectable metastatic traits in breast cancer. eLife 2014; 3. [PMID: 24898756 PMCID: PMC4073284 DOI: 10.7554/elife.02734] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/31/2014] [Indexed: 12/13/2022] Open
Abstract
The mechanisms through which cancer cells lock in altered transcriptional programs in support of metastasis remain largely unknown. Through integrative analysis of clinical breast cancer gene expression datasets, cell line models of breast cancer progression, and mutation data from cancer genome resequencing studies, we identified RNA binding motif protein 47 (RBM47) as a suppressor of breast cancer progression and metastasis. RBM47 inhibited breast cancer re-initiation and growth in experimental models. Transcriptome-wide HITS-CLIP analysis revealed widespread RBM47 binding to mRNAs, most prominently in introns and 3′UTRs. RBM47 altered splicing and abundance of a subset of its target mRNAs. Some of the mRNAs stabilized by RBM47, as exemplified by dickkopf WNT signaling pathway inhibitor 1, inhibit tumor progression downstream of RBM47. Our work identifies RBM47 as an RNA-binding protein that can suppress breast cancer progression and demonstrates how the inactivation of a broadly targeted RNA chaperone enables selection of a pro-metastatic state. DOI:http://dx.doi.org/10.7554/eLife.02734.001 Tumors form when mistakes in the genes of a single cell allow it to multiply uncontrollably. Sometimes further mutations in genes allow the cancerous cells to escape from the tumor, enter the bloodstream and start a second cancer elsewhere in the body. However, many of the genetic changes behind this process, which is called metastasis, are poorly understood—especially those changes in genes that occur rarely, but can still help the cancer to spread. Vanharanta, Marney et al. have looked at data on which genes are switched ‘on’ or ‘off’ in metastatic breast cancer cells. A gene called RBM47 was often switched off in these cells, and patients with a low level of RBM47 tended to have a poor clinical outcome. To test the function of the gene, Vanharanta, Marney et al. switched on RBM47 in cancer cells that had spread from the breast to either the lungs or the brain, and then injected these cells into mice. Few of these cells were able to invade lung and brain tissues in the mice. However, switching off the RBM47 gene in breast cancer cells had the opposite effect; these cells invaded the lungs of mice more efficiently. RBM47 encodes a protein that sticks to molecules of messenger RNA: molecules that transport the instructions encoded in DNA to the machinery that builds proteins. Vanharanta, Marney et al. found that the wild-type RBM47 protein increased the levels of 102 different messenger RNA molecules, but decreased the levels of another 92. Further experiments showed that RBM47 also slows the rate at which messenger RNA molecules are broken down inside cells: this results in the accumulation of proteins that slow down the growth of tumors. Without RBM47, tumor growth is unleashed. Further work is needed to test if increasing RBM47 activity could be used as a new treatment for some types of cancer. DOI:http://dx.doi.org/10.7554/eLife.02734.002
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Affiliation(s)
- Sakari Vanharanta
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, United States
| | - Christina B Marney
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States
| | - Weiping Shu
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, United States
| | - Manuel Valiente
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, United States
| | - Yilong Zou
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, United States
| | - Aldo Mele
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States
| | - Robert B Darnell
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States
| | - Joan Massagué
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, United States
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Al-Ejeh F, Staudacher AH, Smyth DR, Darby JM, Denoyer D, Tsopelas C, Hicks RJ, Brown MP. Postchemotherapy and tumor-selective targeting with the La-specific DAB4 monoclonal antibody relates to apoptotic cell clearance. J Nucl Med 2014; 55:772-9. [PMID: 24676755 DOI: 10.2967/jnumed.113.130559] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Early identification of tumor responses to treatment is crucial for devising more effective and safer cancer treatments. No widely applicable, noninvasive method currently exists for specifically detecting tumor cell death after cytotoxic treatment and thus for predicting treatment outcomes. METHODS We have further characterized the targeting of the murine monoclonal antibody DAB4 specifically to dead tumor cells in vitro, in vivo, and in clinical samples. We found that sustained DAB4 binding to treated cells was closely associated with markers of intrinsic apoptosis and DNA double-strand break formation. In a competition binding assay, DAB4 bound EL4 murine thymic lymphoma cells in preference to the normal counterpart of murine thymocytes. Defective in vivo clearance of apoptotic cells augmented in vivo accumulation of DAB4 in tumors particularly after chemotherapy but was unchanged in normal tissues. Tumor targeting of DAB4 was selective for syngeneic murine tumors and for human tumor xenografts of prostate cancer (PC-3) and pancreatic cancer (Panc-1) before and more so after chemotherapy. Furthermore, DAB4 was shown to bind to dead primary acute lymphoblastic leukemic blasts cultured with cytotoxic drugs and dead epithelial cancer cells isolated from peripheral blood of small cell lung carcinoma patients given chemotherapy. CONCLUSION Collectively, these results further demonstrate the selectivity of DAB4 for chemotherapy-induced dead tumor cells. This postchemotherapy selectivity is related to a relative increase in the availability of DAB4-binding targets in tumor tissue rather than in normal tissues. The in vitro findings were translated in vivo to human xenograft models and to ex vivo analyses of clinical samples, providing further evidence of the potential of DAB4 as a marker of tumor cell death after DNA-damaging cytotoxic treatment that could be harnessed as a predictive marker of treatment responses.
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Affiliation(s)
- Fares Al-Ejeh
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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45
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Penfold SN, Brown MP, Staudacher AH, Bezak E. Monte Carlo simulations of dose distributions with necrotic tumor targeted radioimmunotherapy. Appl Radiat Isot 2014; 90:40-5. [PMID: 24685493 DOI: 10.1016/j.apradiso.2014.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 12/11/2013] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
Radio-resistant hypoxic tumor cells are significant contributors to the locoregional recurrences and distant metastases that mark failure of radiotherapy. Due to restricted tissue oxygenation, chronically hypoxic tumor cells frequently become necrotic and thus there is often an association between chronically hypoxic and necrotic tumor regions. This simulation study is the first in a series to determine the feasibility of hypoxic cell killing after first targeting adjacent areas of necrosis with either an α- or β-emitting radioimmunoconjugate.
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Affiliation(s)
- Scott N Penfold
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Michael P Brown
- Cancer Clinical Trials Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology, Adelaide, SA 5000, Australia
| | - Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology, Adelaide, SA 5000, Australia
| | - Eva Bezak
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005, Australia
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46
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Staudacher AH, Al-Ejeh F, Fraser CK, Darby JM, Roder DM, Ruszkiewicz A, Manavis J, Brown MP. The La antigen is over-expressed in lung cancer and is a selective dead cancer cell target for radioimmunotherapy using the La-specific antibody APOMAB®. EJNMMI Res 2014; 4:2. [PMID: 24387284 PMCID: PMC3882100 DOI: 10.1186/2191-219x-4-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/23/2013] [Indexed: 11/21/2022] Open
Abstract
Background The lupus-associated (La)-specific murine monoclonal antibody DAB4 (APOMAB®) specifically binds dead cancer cells. Using DAB4, we examined La expression in human lung cancer samples to assess its suitability as a cancer-selective therapeutic target. We evaluated the safety and effectiveness of radioimmunotherapy (RIT) using DAB4 radiolabeled with Lutetium-177 (177Lu) in the murine Lewis Lung (LL2) carcinoma model, and determined whether combining RIT with DNA-damaging cisplatin-based chemotherapy, a PARP inhibitor (PARPi), or both alters treatment responses. Methods The expression of La mRNA in human lung cancer samples was analysed using the online database Oncomine, and the protein expression of La was examined using a TissueFocus Cancer Survey Tissue Microarray. The binding of DAB4 to cisplatin-treated LL2 cells was assessed in vitro. LL2 tumour-bearing mice were administered escalating doses of 177Lu-DAB4 alone or in combination with chemotherapy, and tumour growth and survival measured. Biodistribution analysis was used to determine tissue uptake of 177Lu-DAB4 or its isotype control (177Lu-Sal5), when delivered alone or after chemotherapy. PARPi (rucaparib; AG-014699) was combined with chemotherapy and the effects of combined treatment on tumour growth, tumour cell DNA damage and death, and intratumoural DAB4 binding were also analysed. The effect of the triple combination of PARPi, chemotherapy and 177Lu-DAB4 on tumour growth and survival of LL2 tumour-bearing mice was tested. Results La was over-expressed at both mRNA and protein levels in surgical specimens of human lung cancer and the over-expression of La mRNA conferred a poorer prognosis. DAB4 bound specifically to cisplatin-induced dead LL2 cells in vitro. An anti-tumour dose response was observed when escalating doses of 177Lu-DAB4 were delivered in vivo, with supra-additive responses observed when chemotherapy was combined with 177Lu-DAB4. Combining PARPi with chemotherapy was more effective than chemotherapy alone with increased tumour cell DNA damage and death, and intratumoural DAB4 binding. The combination of PARPi, chemotherapy and 177Lu-DAB4 was well-tolerated and maximised tumour growth delay. Conclusions The La antigen represents a dead cancer cell-specific target in lung cancer, and DAB4 specifically targeted tumour tissue in vivo, particularly after chemotherapy. Tumour uptake of DAB4 increased further after the combination of PARPi and chemotherapy, which generated new dead tumour cell-binding targets. Consequently, combining 177Lu-DAB4 with PARPi and chemotherapy produced the greatest anti-tumour response. Therefore, the triple combination of PARPi, chemotherapy and RIT may have broad clinical utility.
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Affiliation(s)
- Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology, Adelaide, Australia.
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Gaidamakov S, Maximova OA, Chon H, Blewett NH, Wang H, Crawford AK, Day A, Tulchin N, Crouch RJ, Morse HC, Blitzer RD, Maraia RJ. Targeted deletion of the gene encoding the La autoantigen (Sjögren's syndrome antigen B) in B cells or the frontal brain causes extensive tissue loss. Mol Cell Biol 2014; 34:123-31. [PMID: 24190965 PMCID: PMC3911279 DOI: 10.1128/mcb.01010-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/09/2013] [Accepted: 10/23/2013] [Indexed: 11/20/2022] Open
Abstract
La antigen (Sjögren's syndrome antigen B) is a phosphoprotein associated with nascent precursor tRNAs and other RNAs, and it is targeted by autoantibodies in patients with Sjögren's syndrome, systemic lupus erythematosus, and neonatal lupus. Increased levels of La are associated with leukemias and other cancers, and various viruses usurp La to promote their replication. Yeast cells (Saccharomyces cerevisiae and Schizosaccharomyces pombe) genetically depleted of La grow and proliferate, whereas deletion from mice causes early embryonic lethality, raising the question of whether La is required by mammalian cells generally or only to surpass a developmental stage. We developed a conditional La allele and used it in mice that express Cre recombinase in either B cell progenitors or the forebrain. B cell Mb1(Cre) La-deleted mice produce no B cells. Consistent with αCamKII Cre, which induces deletion in hippocampal CA1 cells in the third postnatal week and later throughout the neocortex, brains develop normally in La-deleted mice until ∼5 weeks and then lose a large amount of forebrain cells and mass, with evidence of altered pre-tRNA processing. The data indicate that La is required not only in proliferating cells but also in nondividing postmitotic cells. Thus, La is essential in different cell types and required for normal development of various tissue types.
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Affiliation(s)
- Sergei Gaidamakov
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Olga A. Maximova
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Hyongi Chon
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Nathan H. Blewett
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Hongsheng Wang
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Amanda K. Crawford
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Amanda Day
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Natalie Tulchin
- Department of Pathology, Mount Sinai School of Medicine, New York, New York, USA
| | - Robert J. Crouch
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Herbert C. Morse
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert D. Blitzer
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, USA
| | - Richard J. Maraia
- Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Commissioned Corps, U.S. Public Health Service, Washington, DC, USA
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A comprehensive review of autoantibodies in primary Sjögren's syndrome: clinical phenotypes and regulatory mechanisms. J Autoimmun 2013; 51:67-74. [PMID: 24333103 DOI: 10.1016/j.jaut.2013.11.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 11/13/2013] [Indexed: 12/14/2022]
Abstract
Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by periepithelial lymphocytic infiltrates in affected tissues and the production of plethora of autoantibodies. Among them autoimmune responses against Ro/SSA and La/SSB are of major importance since their detection is routinely used for disease diagnosis and clinical characterization. Although the exact mechanisms underlying disease pathogenesis are not fully understood, the important role of salivary gland epithelial cells (SGEC) in the initiation and development of the local immune responses is well-established. SGECs are also capable to mediate the exposure of the Ro/SSA and La/SSB autoantigens to the immune system by elevated apoptosis and autoantigen release in apoptotic bodies and/or by the secretion of autoantigen-containing exosomes. The expression of these autoantigens in epithelial cells appears to be tightly regulated. Up-to-date, signaling of certain innate immunity receptors, such as TLR3, appear to be implicated in the regulation of Ro/SSA and La/SSB expression by SGECs, whereas the deregulated expression of certain miRNAs that are predicted to target them in SS patients suggests a regulatory feedback at the post-transcriptional level. In the periphery, the humoral autoimmune responses are further regulated by the development of an active network of idiotypic-antiidiotypic antibodies. The plethora of mechanisms suggests that autoimmune humoral responses in SS are tightly regulated. In this review, the major humoral autoimmune responses, recent advances on the role of epithelial cells in their development, as well as possible regulatory mechanisms will be discussed.
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Hussain RH, Zawawi M, Bayfield MA. Conservation of RNA chaperone activity of the human La-related proteins 4, 6 and 7. Nucleic Acids Res 2013; 41:8715-25. [PMID: 23887937 PMCID: PMC3794603 DOI: 10.1093/nar/gkt649] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/28/2013] [Accepted: 07/03/2013] [Indexed: 12/22/2022] Open
Abstract
The La module is a conserved tandem arrangement of a La motif and RNA recognition motif whose function has been best characterized in genuine La proteins. The best-characterized substrates of La proteins are pre-tRNAs, and previous work using tRNA mediated suppression in Schizosaccharomyces pombe has demonstrated that yeast and human La enhance the maturation of these using two distinguishable activities: UUU-3'OH-dependent trailer binding/protection and a UUU-3'OH independent activity related to RNA chaperone function. The La module has also been identified in several conserved families of La-related proteins (LARPs) that engage other RNAs, but their mode of RNA binding and function(s) are not well understood. We demonstrate that the La modules of the human LARPs 4, 6 and 7 are also active in tRNA-mediated suppression, even in the absence of stable UUU-3'OH trailer protection. Rather, the capacity of these to enhance pre-tRNA maturation is associated with RNA chaperone function, which we demonstrate to be a conserved activity for each hLARP in vitro. Our work reveals insight into the mechanisms by which La module containing proteins discriminate RNA targets and demonstrates that RNA chaperone activity is a conserved function across representative members of the La motif-containing superfamily.
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Affiliation(s)
| | | | - Mark A. Bayfield
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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Guo P, Lan J, Ge J, Nie Q, Mao Q, Qiu Y. miR-708 acts as a tumor suppressor in human glioblastoma cells. Oncol Rep 2013; 30:870-6. [PMID: 23754151 DOI: 10.3892/or.2013.2526] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/03/2013] [Indexed: 11/06/2022] Open
Abstract
Glioblastoma (GBM) is one of the most lethal forms of human cancer, and new clinical biomarkers and therapeutic targets are urgently required. microRNAs (miRNAs) are small, non-coding RNAs that negatively regulate gene expression at the post-transcriptional and/or translational level by binding the 3' untranslated regions (3' UTRs) of target mRNAs. The dysregulated expression of several miRNAs has been reported to modulate glioma progression. In the present study, we defined the expression and function of miR-708, which, based on real-time PCR analysis, were downregulated in GBM cells. The overexpression of miR-708 inhibited cell proliferation and invasion and induced apoptosis in the human GBM cell lines A172 and T98G. Furthermore, the overexpression of miR-708 reduced the expression of Akt1, CCND1, MMP2, EZH2, Parp-1 and Bcl2 in A172 and T98G cells. Taken together, our study suggests that miR-708 affects GBM cell proliferation and invasion, and induces apoptosis. It is suggested that miR-708 may play an important role as a tumor suppressor in GBM and it may be an attractive target for therapeutic intervention in GBM.
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Affiliation(s)
- Pin Guo
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, PR China
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