1
|
Okpara MO, Hermann C, van der Watt PJ, Garnett S, Blackburn JM, Leaner VD. A mass spectrometry-based approach for the identification of Kpnβ1 binding partners in cancer cells. Sci Rep 2022; 12:20171. [PMID: 36418423 PMCID: PMC9684564 DOI: 10.1038/s41598-022-24194-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 11/11/2022] [Indexed: 11/25/2022] Open
Abstract
Karyopherin beta 1 (Kpnβ1) is the principal nuclear importer of cargo proteins and plays a role in many cellular processes. Its expression is upregulated in cancer and essential for cancer cell viability, thus the identification of its binding partners might help in the discovery of anti-cancer therapeutic targets and cancer biomarkers. Herein, we applied immunoprecipitation coupled to mass spectrometry (IP-MS) to identify Kpnβ1 binding partners in normal and cancer cells. IP-MS identified 100 potential Kpnβ1 binding partners in non-cancer hTERT-RPE1, 179 in HeLa cervical cancer, 147 in WHCO5 oesophageal cancer and 176 in KYSE30 oesophageal cancer cells, including expected and novel interaction partners. 38 binding proteins were identified in all cell lines, with the majority involved in RNA metabolism. 18 binding proteins were unique to the cancer cells, with many involved in protein translation. Western blot analysis validated the interaction of known and novel binding partners with Kpnβ1 and revealed enriched interactions between Kpnβ1 and select proteins in cancer cells, including proteins involved in cancer development, such as Kpnα2, Ran, CRM1, CCAR1 and FUBP1. Together, this study shows that Kpnβ1 interacts with numerous proteins, and its enhanced interaction with certain proteins in cancer cells likely contributes to the cancer state.
Collapse
Affiliation(s)
- Michael O. Okpara
- grid.7836.a0000 0004 1937 1151Division of Medical Biochemistry and Structural Biology, University of Cape Town, Cape Town, South Africa
| | - Clemens Hermann
- grid.7836.a0000 0004 1937 1151Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Pauline J. van der Watt
- grid.7836.a0000 0004 1937 1151Division of Medical Biochemistry and Structural Biology, University of Cape Town, Cape Town, South Africa ,grid.7836.a0000 0004 1937 1151Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Shaun Garnett
- grid.7836.a0000 0004 1937 1151Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Jonathan M. Blackburn
- grid.7836.a0000 0004 1937 1151Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa ,grid.7836.a0000 0004 1937 1151Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Virna D. Leaner
- grid.7836.a0000 0004 1937 1151Division of Medical Biochemistry and Structural Biology, University of Cape Town, Cape Town, South Africa ,grid.7836.a0000 0004 1937 1151SAMRC Gynaecology Cancer Research Centre, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
2
|
Samaddar S, Purkayastha S, Diallo S, Tantry SJ, Schroder R, Chanthrakumar P, Flory MJ, Banerjee P. The G Protein-Coupled Serotonin 1A Receptor Augments Protein Kinase Cε-Mediated Neurogenesis in Neonatal Mouse Hippocampus-PKCε-Mediated Signaling in the Early Hippocampus. Int J Mol Sci 2022; 23:1962. [PMID: 35216076 PMCID: PMC8878481 DOI: 10.3390/ijms23041962] [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: 01/06/2022] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 01/14/2023] Open
Abstract
The neurotransmitter serotonin (5-HT) plays an important role in mood disorders. It has been demonstrated that 5-HT signaling through 5-HT1A receptors (5-HT1A-R) is crucial for early postnatal hippocampal development and later-life behavior. Although this suggests that 5-HT1A-R signaling regulates early brain development, the mechanistic underpinnings of this process have remained unclear. Here we show that stimulation of the 5-HT1A-R at postnatal day 6 (P6) by intrahippocampal infusion of the agonist 8-OH-DPAT (D) causes signaling through protein kinase Cε (PKCε) and extracellular receptor activated kinase ½ (ERK1/2) to boost neuroblast proliferation in the dentate gyrus (DG), as displayed by an increase in bromodeoxy-uridine (BrdU), doublecortin (DCX) double-positive cells. This boost in neuroproliferation was eliminated in mice treated with D in the presence of a 5-HT1A-R antagonist (WAY100635), a selective PKCε inhibitor, or an ERK1/2-kinase (MEK) inhibitor (U0126). It is believed that hippocampal neuro-progenitors undergoing neonatal proliferation subsequently become postmitotic and enter the synaptogenesis phase. Double-staining with antibodies against bromodeoxyuridine (BrdU) and neuronal nuclear protein (NeuN) confirmed that 5-HT1A-R → PKCε → ERK1/2-mediated boosted neuroproliferation at P6 also leads to an increase in BrdU-labeled granular neurons at P36. This 5-HT1A-R-mediated increase in mature neurons was unlikely due to suppressed apoptosis, because terminal deoxynucleotidyl transferase dUTP nick-end labeling analysis showed no difference in DNA terminal labeling between vehicle and 8-OH-DPAT-infused mice. Therefore, 5-HT1A-R signaling through PKCε may play an important role in micro-neurogenesis in the DG at P6, following which many of these new-born neuroprogenitors develop into mature neurons.
Collapse
Affiliation(s)
- Sreyashi Samaddar
- Department of Physical Therapy, The College of Staten Island, City University of New York, Staten Island, NY 10314, USA;
| | | | | | | | - Ryan Schroder
- Eurofins Lancaster PSS, Merck Sharp and Dohme, Rahway, NJ 07065, USA;
| | | | - Michael J. Flory
- Research Design and Analysis Service, New York State Institute for Developmental Disabilities, Staten Island, NY 10314, USA;
| | - Probal Banerjee
- Department of Chemistry, Center for Developmental Neuroscience, The College of Staten Island, City University of New York, Staten Island, NY 10314, USA
| |
Collapse
|
3
|
van der Watt PJ, Okpara MO, Wishart A, Parker MI, Soares NC, Blackburn JM, Leaner VD. Nuclear transport proteins are secreted by cancer cells and identified as potential novel cancer biomarkers. Int J Cancer 2021; 150:347-361. [PMID: 34591985 DOI: 10.1002/ijc.33832] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/20/2021] [Accepted: 09/20/2021] [Indexed: 12/21/2022]
Abstract
Previous studies have identified increased expression of members of the nuclear transport protein family in cancer cells. Recently, certain nuclear transport proteins have been reported to be secreted by cells and found in the serum. The aims of our study were to investigate the levels of multiple nuclear transport proteins secreted from cancer cells, and to determine their potential as diagnostic markers for cervical and oesophageal cancer. Mass spectrometry identified 10 nuclear transport proteins in the secretome and exosomes of cultured cancer cells, and Western blot analysis confirmed increased secreted levels in cancer cells compared to normal. To investigate their presence in patient serum, enzyme-linked immunosorbent assays were performed and revealed significantly increased levels of KPNβ1, CRM1, CAS, IPO5 and TNPO1 in cervical and oesophageal cancer patient serum compared to non-cancer controls. Significantly elevated KPNα2 and RAN levels were also identified in oesophageal cancer serum samples. Logistics regression analyses revealed IPO5 and TNPO1 to be the best performing individual candidate biomarkers in discriminating between cancer cases and controls. The combination of KPNβ1, CRM1, KPNα2, CAS, RAN, IPO5 and TNPO1 as a panel of biomarkers had the highest diagnostic capacity with an area under the curve of 0.944 and 0.963, for cervical cancer and oesophageal cancer, and sensitivity of 92.5% at 86.8% specificity and 95.3% sensitivity at 87.5% specificity, respectively. These results suggest that nuclear transport proteins have potential as diagnostic biomarkers for cervical and oesophageal cancers, with a combination of protein family members being the best predictor.
Collapse
Affiliation(s)
- Pauline J van der Watt
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Michael O Okpara
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Andrew Wishart
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - M Iqbal Parker
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Nelson C Soares
- Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Jonathan M Blackburn
- Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,Division of Chemical and Systems Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Virna D Leaner
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,SAMRC Gynaecology Cancer Research Centre, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
4
|
Ajayi-Smith A, van der Watt P, Mkwanazi N, Carden S, Trent JO, Leaner VD. Novel small molecule inhibitor of Kpnβ1 induces cell cycle arrest and apoptosis in cancer cells. Exp Cell Res 2021; 404:112637. [PMID: 34019908 DOI: 10.1016/j.yexcr.2021.112637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 04/02/2021] [Accepted: 05/02/2021] [Indexed: 12/11/2022]
Abstract
Karyopherin beta 1 (Kpnβ1) is a major nuclear import receptor that mediates the import of cellular cargoes into the nucleus. Recently it has been shown that Kpnβ1 is highly expressed in several cancers, and its inhibition by siRNA induces apoptotic cancer cell death, while having little effect on non-cancer cells. This study investigated the effect of a novel small molecule, Inhibitor of Nuclear Import-60 (INI-60), on cancer cell biology, as well as nuclear import activities associated with Kpnβ1, and cancer progression in vivo using cervical and oesophageal cancer cell lines. INI-60 treatment resulted in the inhibition of cancer cell proliferation, colony formation, migration and invasion, and induced a G1/S cell cycle arrest, followed by cancer cell death via apoptosis. Non-cancer cells were minimally affected by INI-60 at concentrations that inhibited cancer cells. INI-60 treatment altered the localisation of Kpnβ1 and its cargoes, NFκB/p65, NFAT and AP-1, and the overexpression of Kpnβ1 reduced INI-60 cytotoxicity. INI-60 also inhibited KYSE 30 oesophageal cancer cell line growth in vivo. Taken together, these results show that INI-60 inhibits the nuclear import of Kpnβ1 cargoes and interferes with cancer cell biology. INI-60 presents as a potential therapeutic approach for cancers of different tissue origins and warrants further investigation as a novel anti-cancer agent.
Collapse
Affiliation(s)
- Aderonke Ajayi-Smith
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, #SAMRC Gynaecology Cancer Research Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
| | - Pauline van der Watt
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, #SAMRC Gynaecology Cancer Research Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
| | - Nonkululeko Mkwanazi
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, #SAMRC Gynaecology Cancer Research Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
| | - Sarah Carden
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, #SAMRC Gynaecology Cancer Research Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
| | - John O Trent
- Department of Medicine, J.G. Brown Cancer Center, University of Louisville, Kentucky, USA
| | - Virna D Leaner
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, #SAMRC Gynaecology Cancer Research Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa.
| |
Collapse
|
5
|
Tanaka T, Togashi Y, Takeuchi Y, Higashi M, Fumino S, Tajiri T. Immunohistochemical staining of phosphorylated-ERK in post-chemotherapeutic samples is a potential predictor of the prognosis of neuroblastoma. Pediatr Surg Int 2021; 37:287-291. [PMID: 33394087 DOI: 10.1007/s00383-020-04806-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/06/2020] [Indexed: 01/08/2023]
Abstract
PURPOSE The majority of relapsed neuroblastomas have mitogen-activated protein kinase (MAPK) pathway activating mutations. We previously showed the in vitro and in vivo anti-tumor effects of MAPK/ERK kinase (MEK) inhibitors in MAPK-activated neuroblastoma. We herein assessed the correlation between MAPK activation and the prognosis in neuroblastoma patients using phosphorylated extra-cellular signal-regulated kinase (pERK) immunohistochemistry to establish the protocol for the clinical administration of MEK inhibitors. METHODS Neuroblastoma samples from patients treated in our hospital were immunostained with pERK. The clinical outcomes were retrospectively collected from medical records. The correlation between pERK positivity and the prognosis was analyzed. RESULTS Regarding pre-chemotherapeutic specimens, there were no differences in the pERK status between tumors with a good and bad prognosis in both the nuclei and cytoplasm. Regarding post-chemotherapeutic specimens, one of eight tumors with a good prognosis and four of six tumors with a poor prognosis showed pERK-positive nuclear staining (p = 0.0909) and five of eight tumors with a good prognosis and four of six tumors with a poor prognosis showed pERK-positive cytoplasmic staining (p > 0.9999). CONCLUSION These findings suggested post-chemotherapeutic-not pre-chemotherapeutic-nuclear pERK-positive neuroblastoma tends to be associated with a poor prognosis and may be a potential therapeutic target for MEK inhibitor treatment.
Collapse
Affiliation(s)
- Tomoko Tanaka
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
| | - Yuichi Togashi
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yuki Takeuchi
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Mayumi Higashi
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Shigehisa Fumino
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Tatsuro Tajiri
- Department of Pediatric Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| |
Collapse
|
6
|
Ishikawa C, Senba M, Mori N. Importin β1 regulates cell growth and survival during adult T cell leukemia/lymphoma therapy. Invest New Drugs 2020; 39:317-329. [PMID: 32959166 DOI: 10.1007/s10637-020-01007-z] [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: 08/17/2020] [Accepted: 09/16/2020] [Indexed: 10/23/2022]
Abstract
There is no cure for adult T cell leukemia/lymphoma (ATLL) associated with human T cell leukemia virus type 1 (HTLV-1), and novel targeted strategies are needed. NF-κB and AP-1 are crucial for ATLL, and both are transported to the nucleus by an importin (IPO)α/β heterodimeric complex to activate target genes. In this study, we aimed to elucidate the function of IPOβ1 in ATLL. The expression of IPOβ1 was analyzed by western blotting and RT-PCR. Cell growth, viability, cell cycle, apoptosis and intracellular signaling cascades were examined by the water-soluble tetrazolium-8 assay, flow cytometry and western blotting. Xenograft tumors in severe combined immune deficient mice were used to evaluate the growth of ATLL cells in vivo. IPOβ1 was upregulated in HTLV-1-infected T cell lines. Further, IPOβ1 knockdown or the IPOβ1 inhibitor importazole and the IPOα/β1 inhibitor ivermectin reduced HTLV-1-infected T cell proliferation. However, the effect of inhibitors on uninfected T cells was less pronounced. Further, in HTLV-1-infected T cell lines, inhibitors suppressed NF-κB and AP-1 nuclear transport and DNA binding, induced apoptosis and poly (ADP-ribose) polymerase cleavage, and activated caspase-3, caspase-8 and caspase-9. Inhibitors also mediated G1 cell cycle arrest. Moreover, the expression of NF-κB- and AP-1-target proteins involved in cell cycle and apoptosis was reduced. In vivo, the IPOα/β1 inhibitor ivermectin decreased ATLL tumor burden without side effects. IPOβ1 mediated NF-κB and AP-1 translocation into ATLL cell nuclei, thereby regulating cell growth and survival, which provides new insights for targeted ATLL therapies. Thus, ivermectin, an anti-strongyloidiasis medication, could be a potent anti-ATLL agent.
Collapse
Affiliation(s)
- Chie Ishikawa
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan.,Division of Health Sciences, Transdisciplinary Research Organization for Subtropics and Island Studies, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Masachika Senba
- Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Naoki Mori
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan.
| |
Collapse
|
7
|
Carden S, van der Watt P, Chi A, Ajayi-Smith A, Hadley K, Leaner VD. A tight balance of Karyopherin β1 expression is required in cervical cancer cells. BMC Cancer 2018; 18:1123. [PMID: 30445944 PMCID: PMC6240311 DOI: 10.1186/s12885-018-5044-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 11/05/2018] [Indexed: 01/13/2023] Open
Abstract
Background Karyopherin β1 (Kpnβ1) is the main nuclear import protein involved in the transport of cargoes from the cytoplasm into the cell nucleus. Previous research has found Kpnβ1 to be significantly overexpressed in cervical cancer and other cancer tissues, and further studies showed that inhibition of Kpnβ1 expression by siRNA resulted in cancer cell death, while non-cancer cells were minimally affected. These results suggest that Kpnβ1 has potential as an anticancer therapeutic target, thus warranting further research into the association between Kpnβ1 expression and cancer progression. Here, the biological effects associated with Kpnβ1 overexpression were investigated in order to further elucidate the relationship between Kpnβ1 and the cancer phenotype. Methods To evaluate the effect of Kpnβ1 overexpression on cell biology, cell proliferation, cell cycle, cell morphology and cell adhesion assays were performed. To determine whether Kpnβ1 overexpression influences cell sensitivity to chemotherapeutic agents like Cisplatin, cell viability assays were performed. Expression levels of key proteins were analysed by Western blot analysis. Results Our data revealed that Kpnβ1 overexpression, above that which was already detected in cancer cells, resulted in reduced proliferation of cervical cancer cells. Likewise, normal epithelial cells showed reduced proliferation after Kpnβ1 overxpression. Reduced cancer cell proliferation was associated with a delay in cell cycle progression, as well as changes in the morphology and adhesion properties of cells. Additionally, Kpnβ1 overexpressing HeLa cells exhibited increased sensitivity to cisplatin, as shown by decreased cell viability and increased apoptosis, where p53 and p21 inhibition reduced and enhanced cell sensitivity to Cisplatin, respectively. Conclusions Overall, our results suggest that a tight balance of Kpnβ1 expression is required for cellular function, and that perturbation of this balance results in negative effects associated with a variety of biological processes. Electronic supplementary material The online version of this article (10.1186/s12885-018-5044-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sarah Carden
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Pauline van der Watt
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Alicia Chi
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Aderonke Ajayi-Smith
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Katie Hadley
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Virna D Leaner
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. .,Division of Medical Biochemistry and Structural Biology, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| |
Collapse
|
8
|
Karyopherins in cancer. Curr Opin Cell Biol 2018; 52:30-42. [PMID: 29414591 DOI: 10.1016/j.ceb.2018.01.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/08/2018] [Accepted: 01/14/2018] [Indexed: 12/16/2022]
Abstract
Malfunction of nuclear-cytoplasmic transport contributes to many diseases including cancer. Defective nuclear transport leads to changes in both the physiological levels and temporal-spatial location of tumor suppressors, proto-oncogenes and other macromolecules that in turn affect the tumorigenesis process and drug sensitivity of cancer cells. In addition to their nuclear transport functions in interphase, Karyopherin nuclear transport receptors also have important roles in mitosis and chromosomal integrity. Therefore, alterations in the expressions or regular functions of Karyopherins may have substantial effects on the course and outcome of diseases.
Collapse
|
9
|
Ha S, Oh J, Kim YH, Ham SW. Determination of the binding site of 2-aminothiazole derivative with importin β1 by UV-crosslinking experiment. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1060:71-75. [PMID: 28600962 DOI: 10.1016/j.jchromb.2017.05.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Importin β1 (KPBN1) appears to be overexpressed in several cancer cells and siRNA-induced inhibition of KPNB1 shows significant inhibition of cancer cell proliferation, but do not affect normal cells. These results indicate that KPNB1 is a potential target and inhibition of KPNB1 can be used as a novel therapeutic approach for the treatment of cancer. Recently, we identified the aminothiazole derivative 1 as a KPNB1-targeted anticancer agent. Herein, we report that compound 1 binds strongly to KPNB1, in a pocket centered around serine-476, as shown by UV-crosslinking and tandem mass spectrometry experiments, and supported using a model derived from molecular docking.
Collapse
Affiliation(s)
- Siyoung Ha
- Department of Chemistry, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jiwon Oh
- Department of Chemistry, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Yong-Hak Kim
- Department of Catholic, University of Daegu, School of Medicine, Daegu 705-718, Republic of Korea.
| | - Seung Wook Ham
- Department of Chemistry, Chung-Ang University, Seoul 06974, Republic of Korea.
| |
Collapse
|
10
|
Ha S, Oh J, Jang JM, Kim DK, Ham SW. Synthesis and Biological Evaluation of 2-Aminothiazole Derivative Having Anticancer Activity as a KPNB1 Inhibitor. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Siyoung Ha
- Department of Chemistry; Chung-Ang University; Seoul 06974 Republic of Korea
| | - Jiwon Oh
- Department of Chemistry; Chung-Ang University; Seoul 06974 Republic of Korea
| | - Ji Min Jang
- College of Pharmacy; Chung-Ang University; Seoul 06974 Republic of Korea
| | - Dae Kyong Kim
- College of Pharmacy; Chung-Ang University; Seoul 06974 Republic of Korea
| | - Seung Wook Ham
- Department of Chemistry; Chung-Ang University; Seoul 06974 Republic of Korea
| |
Collapse
|
11
|
Mahipal A, Malafa M. Importins and exportins as therapeutic targets in cancer. Pharmacol Ther 2016; 164:135-43. [PMID: 27113410 DOI: 10.1016/j.pharmthera.2016.03.020] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/08/2016] [Indexed: 01/01/2023]
Abstract
The nuclear transport proteins, importins and exportins (karyopherin-β proteins), may play an important role in cancer by transporting key mediators of oncogenesis across the nuclear membrane in cancer cells. During nucleocytoplasmic transport of tumor suppressor proteins and cell cycle regulators during the processing of these proteins, aberrant cellular growth signaling and inactivation of apoptosis can occur, both critical to growth and development of tumors. Karyopherin-β proteins bind to these cargo proteins and RanGTP for active transport across the nuclear membrane through the nuclear pore complex. Importins and exportins are overexpressed in multiple tumors including melanoma, pancreatic, breast, colon, gastric, prostate, esophageal, lung cancer, and lymphomas. Furthermore, some of the karyopherin-β proteins such as exportin-1 have been implicated in drug resistance in cancer. Importin and exportin inhibitors are being considered as therapeutic targets against cancer and have shown preclinical anticancer activity. Moreover, synergistic activity has been observed with various chemotherapeutic and targeted agents. However, clinical development of the exportin-1 inhibitor leptomycin B was stopped due to adverse events, including vomiting, anorexia, and dehydration. Selinexor, a selective nuclear export inhibitor, is being tested in multiple clinical trials both as a single agent and in combination with chemotherapy. Selinexor has demonstrated clinical activity in multiple cancers, especially acute myelogenous leukemia and multiple myeloma. The roles of other importin and exportin inhibitors still need to be investigated clinically. Targeting the key mediators of nucleocytoplasmic transport in cancer cells represents a novel strategy in cancer intervention with the potential to significantly affect outcomes.
Collapse
Affiliation(s)
- Amit Mahipal
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, United States
| | - Mokenge Malafa
- Department of Gastrointestinal Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, United States.
| |
Collapse
|
12
|
Stelma T, Chi A, van der Watt PJ, Verrico A, Lavia P, Leaner VD. Targeting nuclear transporters in cancer: Diagnostic, prognostic and therapeutic potential. IUBMB Life 2016; 68:268-80. [PMID: 26970212 DOI: 10.1002/iub.1484] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/20/2016] [Indexed: 01/10/2023]
Abstract
The Karyopherin superfamily is a major class of soluble transport receptors consisting of both import and export proteins. The trafficking of proteins involved in transcription, cell signalling and cell cycle regulation among other functions across the nuclear membrane is essential for normal cellular functioning. However, in cancer cells, the altered expression or localization of nuclear transporters as well as the disruption of endogenous nuclear transport inhibitors are some ways in which the Karyopherin proteins are dysregulated. The value of nuclear transporters in the diagnosis, prognosis and treatment of cancer is currently being elucidated with recent studies highlighting their potential as biomarkers and therapeutic targets.
Collapse
Affiliation(s)
- Tamara Stelma
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Alicia Chi
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Pauline J van der Watt
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Annalisa Verrico
- Institute of Molecular Biology and Pathology, National Research Council of Italy, C/O University of Roma "La Sapienza", Rome, Italy
| | - Patrizia Lavia
- Institute of Molecular Biology and Pathology, National Research Council of Italy, C/O University of Roma "La Sapienza", Rome, Italy
| | - Virna D Leaner
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, SAMRC/UCT Gynaecological Cancer Research Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
13
|
van der Watt PJ, Chi A, Stelma T, Stowell C, Strydom E, Carden S, Angus L, Hadley K, Lang D, Wei W, Birrer MJ, Trent JO, Leaner VD. Targeting the Nuclear Import Receptor Kpnβ1 as an Anticancer Therapeutic. Mol Cancer Ther 2016; 15:560-73. [PMID: 26832790 DOI: 10.1158/1535-7163.mct-15-0052] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 01/15/2016] [Indexed: 11/16/2022]
Abstract
Karyopherin beta 1 (Kpnβ1) is a nuclear transport receptor that imports cargoes into the nucleus. Recently, elevated Kpnβ1 expression was found in certain cancers and Kpnβ1 silencing with siRNA was shown to induce cancer cell death. This study aimed to identify novel small molecule inhibitors of Kpnβ1, and determine their anticancer activity. An in silico screen identified molecules that potentially bind Kpnβ1 and Inhibitor of Nuclear Import-43, INI-43 (3-(1H-benzimidazol-2-yl)-1-(3-dimethylaminopropyl)pyrrolo[5,4-b]quinoxalin-2-amine) was investigated further as it interfered with the nuclear localization of Kpnβ1 and known Kpnβ1 cargoes NFAT, NFκB, AP-1, and NFY and inhibited the proliferation of cancer cells of different tissue origins. Minimum effect on the proliferation of noncancer cells was observed at the concentration of INI-43 that showed a significant cytotoxic effect on various cervical and esophageal cancer cell lines. A rescue experiment confirmed that INI-43 exerted its cell killing effects, in part, by targeting Kpnβ1. INI-43 treatment elicited a G2-M cell-cycle arrest in cancer cells and induced the intrinsic apoptotic pathway. Intraperitoneal administration of INI-43 significantly inhibited the growth of subcutaneously xenografted esophageal and cervical tumor cells. We propose that Kpnβ1 inhibitors could have therapeutic potential for the treatment of cancer. Mol Cancer Ther; 15(4); 560-73. ©2016 AACR.
Collapse
Affiliation(s)
- Pauline J van der Watt
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Alicia Chi
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Tamara Stelma
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Catherine Stowell
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Erin Strydom
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Sarah Carden
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Liselotte Angus
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Kate Hadley
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dirk Lang
- Confocal and Light Microscope Imaging Facility, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Wei Wei
- Center for Cancer Research, The Gillette Center for Gynecologic Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Michael J Birrer
- Center for Cancer Research, The Gillette Center for Gynecologic Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - John O Trent
- Department of Medicine, J.G. Brown Cancer Center, University of Louisville, Louisville, Kentucky
| | - Virna D Leaner
- Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, SAMRC/UCT Gynaecological Cancer Research Centre, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
| |
Collapse
|
14
|
Yan W, Li R, He J, Du J, Hou J. Importin β1 mediates nuclear factor-κB signal transduction into the nuclei of myeloma cells and affects their proliferation and apoptosis. Cell Signal 2015; 27:851-9. [DOI: 10.1016/j.cellsig.2015.01.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/16/2015] [Accepted: 01/23/2015] [Indexed: 11/29/2022]
|
15
|
The nuclear translocation of ERK1/2 as an anticancer target. Nat Commun 2015; 6:6685. [PMID: 25819065 DOI: 10.1038/ncomms7685] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 02/18/2015] [Indexed: 12/22/2022] Open
Abstract
A hallmark of the ERK1/2 functioning is their nuclear translocation, which is mainly required for the induction of proliferation. Activated ERK1/2 molecules that remain in the cytoplasm initiate other activities, including immediate feedback loops. Prevention of the nuclear translocation should therefore inhibit proliferation, without affecting cytoplasm-induced cellular processes. Here we present an NTS-derived myristoylated phosphomimetic peptide, which blocks the interaction of importin7 and ERK1/2, and consequently the nuclear translocation of the latter. In culture, the peptide induces apoptosis of melanoma cells inhibits the viability of other cancer cells, but has no effect on non-transformed, immortalized cells. It even inhibits the viability of PLX4032- and U0126-resistant melanoma cells. In xenograft models, the peptide inhibits several cancers, and acts much better than PLX4032 in preventing melanoma recurrence. This study provides a proof of concept for using the nuclear translocation of ERK1/2 as a drug target for the combat of various ERK1/2-related cancers.
Collapse
|
16
|
Sethi G, Kwon Y, Burkhalter RJ, Pathak HB, Madan R, McHugh S, Atay S, Murthy S, Tawfik OW, Godwin AK. PTN signaling: Components and mechanistic insights in human ovarian cancer. Mol Carcinog 2014; 54:1772-85. [PMID: 25418856 DOI: 10.1002/mc.22249] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/30/2014] [Accepted: 10/10/2014] [Indexed: 12/13/2022]
Abstract
Molecular vulnerabilities represent promising candidates for the development of targeted therapies that hold the promise to overcome the challenges encountered with non-targeted chemotherapy for the treatment of ovarian cancer. Through a synthetic lethality screen, we previously identified pleiotrophin (PTN) as a molecular vulnerability in ovarian cancer and showed that siRNA-mediated PTN knockdown induced apoptotic cell death in epithelial ovarian cancer (EOC) cells. Although, it is well known that PTN elicits its pro-tumorigenic effects through its receptor, protein tyrosine phosphatase receptor Z1 (PTPRZ1), little is known about the potential importance of this pathway in the pathogenesis of ovarian cancer. In this study, we show that PTN is expressed, produced, and secreted in a panel of EOC cell lines. PTN levels in serous ovarian tumor tissues are on average 3.5-fold higher relative to normal tissue and PTN is detectable in serum samples of patients with EOC. PTPRZ1 is also expressed and produced by EOC cells and is found to be up-regulated in serous ovarian tumor tissue relative to normal ovarian surface epithelial tissue (P < 0.05). Gene silencing of PTPRZ1 in EOC cell lines using siRNA-mediated knockdown shows that PTPRZ1 is essential for viability and results in significant apoptosis with no effect on the cell cycle phase distribution. In order to determine how PTN mediates survival, we silenced the gene using siRNA mediated knockdown and performed expression profiling of 36 survival-related genes. Through computational mapping of the differentially expressed genes, members of the MAPK (mitogen-activated protein kinase) family were found to be likely effectors of PTN signaling in EOC cells. Our results provide the first experimental evidence that PTN and its signaling components may be of significance in the pathogenesis of epithelial ovarian cancer and provide a rationale for clinical evaluation of MAPK inhibitors in PTN and/or PTPRZ1 expressing ovarian tumors.
Collapse
Affiliation(s)
- Geetika Sethi
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas.,Department of Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Youngjoo Kwon
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Rebecca J Burkhalter
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Harsh B Pathak
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas.,University of Kansas Cancer Center, Kansas City, Kansas
| | - Rashna Madan
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Sarah McHugh
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Safinur Atay
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Smruthi Murthy
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Ossama W Tawfik
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Andrew K Godwin
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas.,University of Kansas Cancer Center, Kansas City, Kansas
| |
Collapse
|
17
|
Snail promotes epithelial mesenchymal transition in breast cancer cells in part via activation of nuclear ERK2. PLoS One 2014; 9:e104987. [PMID: 25122124 PMCID: PMC4133359 DOI: 10.1371/journal.pone.0104987] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/14/2014] [Indexed: 01/11/2023] Open
Abstract
Snail transcription factor is up-regulated in several cancers and associated with increased tumor migration and invasion via induction of epithelial-to-mesenchymal transition (EMT). MAPK (ERK1/2) signaling regulates cellular processes including cell motility, adhesion, and invasion. We investigated the regulation of ERK1/2 by Snail in breast cancer cells. ERK1/2 activity (p-ERK) was higher in breast cancer patient tissue as compared to normal tissue. Snail and p-ERK were increased in several breast cancer cell lines as compared to normal mammary epithelial cells. Snail knockdown in MDA-MB-231 and T47-D breast cancer cells decreased or re-localized p-ERK from the nuclear compartment to the cytoplasm. Snail overexpression in MCF-7 breast cancer cells induced EMT, increased cell migration, decreased cell adhesion and also increased tumorigenicity. Snail induced nuclear translocation of p-ERK, and the activation of its subcellular downstream effector, Elk-1. Inhibiting MAPK activity with UO126 or knockdown of ERK2 isoform with siRNA in MCF-7 Snail cells reverted EMT induced by Snail as shown by decreased Snail and vimentin expression, decreased cell migration and increased cell adhesion. Overall, our data suggest that ERK2 isoform activation by Snail in aggressive breast cancer cells leads to EMT associated with increased cell migration and decreased cell adhesion. This regulation is enhanced by positive feedback regulation of Snail by ERK2. Therefore, therapeutic targeting of ERK2 isoform may be beneficial for breast cancer.
Collapse
|
18
|
Frohnert C, Hutten S, Wälde S, Nath A, Kehlenbach RH. Importin 7 and Nup358 promote nuclear import of the protein component of human telomerase. PLoS One 2014; 9:e88887. [PMID: 24586428 PMCID: PMC3930611 DOI: 10.1371/journal.pone.0088887] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/13/2014] [Indexed: 01/18/2023] Open
Abstract
In actively dividing eukaryotic cells, chromosome ends (telomeres) are subject to progressive shortening, unless they are maintained by the action of telomerase, a dedicated enzyme that adds DNA sequence repeats to chromosomal 3′end. For its enzymatic function on telomeres, telomerase requires nuclear import of its protein component (hTERT in human cells) and assembly with the RNA component, TERC. We now confirm a major nuclear localization signal (NLS) in the N-terminal region of hTERT and describe a novel one in the C-terminal part. Using an siRNA approach to deplete several import receptors, we identify importin 7 as a soluble nuclear transport factor that is required for efficient import. At the level of the nuclear pore complex (NPC), Nup358, a nucleoporin that forms the cytoplasmic filaments of the NPC, plays an important role in nuclear import of hTERT. A structure-function analysis of Nup358 revealed that the zinc finger region of the nucleoporin is of particular importance for transport of hTERT. Together, our study sheds light on the nuclear import pathway of hTERT.
Collapse
Affiliation(s)
- Cornelia Frohnert
- Institute of Molecular Biology, Faculty of Medicine, University of Göttingen, Göttingen, Germany
| | - Saskia Hutten
- Institute of Molecular Biology, Faculty of Medicine, University of Göttingen, Göttingen, Germany
| | - Sarah Wälde
- Institute of Molecular Biology, Faculty of Medicine, University of Göttingen, Göttingen, Germany
| | - Annegret Nath
- Institute of Molecular Biology, Faculty of Medicine, University of Göttingen, Göttingen, Germany
| | - Ralph H. Kehlenbach
- Institute of Molecular Biology, Faculty of Medicine, University of Göttingen, Göttingen, Germany
- * E-mail:
| |
Collapse
|
19
|
The nuclear lamina regulates germline stem cell niche organization via modulation of EGFR signaling. Cell Stem Cell 2014; 13:73-86. [PMID: 23827710 DOI: 10.1016/j.stem.2013.05.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 03/24/2013] [Accepted: 05/06/2013] [Indexed: 02/08/2023]
Abstract
Stem cell niche interactions have been studied extensively with regard to cell polarity and extracellular signaling. Less is known about the way in which signals and polarity cues integrate with intracellular structures to ensure appropriate niche organization and function. Here, we report that nuclear lamins function in the cyst stem cells (CySCs) of Drosophila testes to control the interaction of CySCs with the hub. This interaction is important for regulation of CySC differentiation and organization of the niche that supports the germline stem cells (GSCs). Lamin promotes nuclear retention of phosphorylated ERK in the CySC lineage by regulating the distribution of specific nucleoporins within the nuclear pores. Lamin-regulated nuclear epidermal growth factor (EGF) receptor signaling in the CySC lineage is essential for proliferation and differentiation of the GSCs and the transient amplifying germ cells. Thus, we have uncovered a role for the nuclear lamina in the integration of EGF signaling to regulate stem cell niche function.
Collapse
|
20
|
Angus L, van der Watt PJ, Leaner VD. Inhibition of the nuclear transporter, Kpnβ1, results in prolonged mitotic arrest and activation of the intrinsic apoptotic pathway in cervical cancer cells. Carcinogenesis 2014; 35:1121-31. [PMID: 24398670 DOI: 10.1093/carcin/bgt491] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The karyopherin β proteins are involved in nuclear-cytoplasmic trafficking and are crucial for protein and RNA subcellular localization. We previously showed that Kpnβ1, a nuclear importin protein, is overexpressed in cervical cancer and is critical for cervical cancer cell survival and proliferation, whereas non-cancer cells are less dependent on its expression. This study aimed to identify the mechanisms by which inhibition of Kpnβ1 results in cervical cancer cell death. We show that the inhibition of Kpnβ1 results in the induction of apoptosis and a prolonged mitotic arrest, accompanied by distinct mitotic defects in cervical cancer cells but not non-cancer cells. In cervical cancer cells, Kpnβ1 downregulation results in sustained degradation of the antiapoptotic protein, Mcl-1, and elevated Noxa expression, as well as mitochondrial membrane permeabilization resulting in the release of cytochrome C and activation of associated caspases. Although p53 becomes stabilized in Kpnβ1 knockdown cervical cancer cells, apoptosis occurs in a p53-independent manner. These results demonstrate that blocking Kpnβ1 has potential as an anticancer therapeutic approach.
Collapse
Affiliation(s)
- Liselotte Angus
- Division of Medical Biochemistry, Faculty of Health Sciences, University of Cape Town, Institute of Infectious Disease and Molecular Medicine, Cape Town 7925, South Africa
| | | | | |
Collapse
|
21
|
Capo-chichi CD, Cai KQ, Smedberg J, Ganjei-Azar P, Godwin AK, Xu XX. Loss of A-type lamin expression compromises nuclear envelope integrity in breast cancer. CHINESE JOURNAL OF CANCER 2012; 30:415-25. [PMID: 21627864 PMCID: PMC3941915 DOI: 10.5732/cjc.010.10566] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Through advances in technology, the genetic basis of cancer has been investigated at the genomic level, and many fundamental questions have begun to be addressed. Among several key unresolved questions in cancer biology, the molecular basis for the link between nuclear deformation and malignancy has not been determined. Another hallmark of human cancer is aneuploidy; however, the causes and consequences of aneuploidy are unanswered and are hotly contested topics. We found that nuclear lamina proteins lamin A/C are absent in a significant fraction (38%) of human breast cancer tissues. Even in lamin A/C–positive breast cancer, lamin A/C expression is heterogeneous or aberrant (such as non-nuclear distribution) in the population of tumor cells, as determined by immunohistology and immunofluorescence microscopy. In most breast cancer cell lines, a significant fraction of the lamin A/C– negative population was observed. To determine the consequences of the loss of lamin A/C, we suppressed their expression by shRNA in non-cancerous primary breast epithelial cells. Down-regulation of lamin A/C in breast epithelial cells led to morphological deformation, resembling that of cancer cells, as observed by immunofluorescence microscopy. The lamin A/C–suppressed breast epithelial cells developed aneuploidy as determined by both flow Cytometry and fluorescence in situ hybridization. We conclude that the loss of nuclear envelope structural proteins lamin A/C in breast cancer underlies the two hallmarks of cancer aberrations in nuclear morphology and aneuploidy.
Collapse
Affiliation(s)
- Callinice D Capo-chichi
- Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Miami, FL 33136, USA
| | | | | | | | | | | |
Collapse
|
22
|
Abstract
Because of the association between aberrant nuclear structure and tumour grade, nuclear morphology is an indispensible criterion in the current pathological assessment of cancer. Components of the nuclear envelope environment have central roles in many aspects of cell function that affect tumour development and progression. As the roles of the nuclear envelope components, including nuclear pore complexes and nuclear lamina, are being deciphered in molecular detail there are opportunities to harness this knowledge for cancer therapeutics and biomarker development. In this Review, we summarize the progress that has been made in our understanding of the nuclear envelope and the implications of changes in this environment for cancer biology.
Collapse
Affiliation(s)
- Kin-Hoe Chow
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | |
Collapse
|
23
|
Golomb L, Bublik DR, Wilder S, Nevo R, Kiss V, Grabusic K, Oren M. Importin 7 and exportin 1 link c-Myc and p53 to regulation of ribosomal biogenesis. Mol Cell 2012; 45:222-32. [PMID: 22284678 PMCID: PMC3270374 DOI: 10.1016/j.molcel.2011.11.022] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 07/13/2011] [Accepted: 11/04/2011] [Indexed: 11/22/2022]
Abstract
Members of the β-karyopherin family mediate nuclear import of ribosomal proteins and export of ribosomal subunits, both required for ribosome biogenesis. We report that transcription of the β-karyopherin genes importin 7 (IPO7) and exportin 1 (XPO1), and several additional nuclear import receptors, is regulated positively by c-Myc and negatively by p53. Partial IPO7 depletion triggers p53 activation and p53-dependent growth arrest. Activation of p53 by IPO7 knockdown has distinct features of ribosomal biogenesis stress, with increased binding of Mdm2 to ribosomal proteins L5 and L11 (RPL5 and RPL11). Furthermore, p53 activation is dependent on RPL5 and RPL11. Of note, IPO7 and XPO1 are frequently overexpressed in cancer. Altogether, we propose that c-Myc and p53 counter each other in the regulation of elements within the nuclear transport machinery, thereby exerting opposing effects on the rate of ribosome biogenesis. Perturbation of this balance may play a significant role in promoting cancer.
Collapse
Affiliation(s)
- Lior Golomb
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Debora Rosa Bublik
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sylvia Wilder
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Reinat Nevo
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Vladimir Kiss
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Kristina Grabusic
- Department of Molecular medicine and Biotechnology, University of Rijeka, School of Medicine, Rijeka 51000, Croatia
| | - Moshe Oren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
24
|
Kuusisto HV, Wagstaff KM, Alvisi G, Roth DM, Jans DA. Global enhancement of nuclear localization-dependent nuclear transport in transformed cells. FASEB J 2011; 26:1181-93. [PMID: 22155563 DOI: 10.1096/fj.11-191585] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fundamental to eukaryotic cell function, nucleocytoplasmic transport can be regulated at many levels, including through modulation of the importin/exportin (Imp/Exp) nuclear transport machinery itself. Although Imps/Exps are overexpressed in a number of transformed cell lines and patient tumor tissues, the efficiency of nucleocytoplasmic transport in transformed cell types compared with nontransformed cells has not been investigated. Here we use quantitative live cell imaging of 3 isogenic nontransformed/transformed cell pairs to show that nuclear accumulation of nuclear localization signal (NLS)-containing proteins, but not their NLS-mutated derivatives, is increased up to 7-fold in MCF10CA1h human epithelial breast carcinoma cells and in simian virus 40 (SV40)-transformed fibroblasts of human and monkey origin, compared with their nontransformed counterparts. The basis for this appears to be a significantly faster rate of nuclear import in transformed cell types, as revealed by analysis using fluorescence recovery after photobleaching for the human MCF10A/MCF10CA1h cell pair. Nuclear accumulation of NLS/nuclear export signal-containing (shuttling) proteins was also enhanced in transformed cell types, experiments using the nuclear export inhibitor leptomycin B demonstrating that efficient Exp-1-mediated nuclear export was not impaired in transformed compared with nontransformed cells. Enhanced nuclear import and export efficiencies were found to correlate with 2- to 4-fold higher expression of specific Imps/Exps in transformed cells, as indicated by quantitative Western blot analysis, with ectopic expression of Imps able to enhance NLS nuclear accumulation levels up to 5-fold in nontransformed MCF10A cells. The findings indicate that transformed cells possess altered nuclear transport properties, most likely due to the overexpression of Imps/Exps. The findings have important implications for the development of tumor-specific drug nanocarriers in anticancer therapy.
Collapse
Affiliation(s)
- Henna V Kuusisto
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | | | | | | | | |
Collapse
|
25
|
|
26
|
Nuclear extracellular signal-regulated kinase 1 and 2 translocation is mediated by casein kinase 2 and accelerated by autophosphorylation. Mol Cell Biol 2011; 31:3515-30. [PMID: 21730285 DOI: 10.1128/mcb.05424-11] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The extracellular signal-regulated kinases (ERK) 1 and 2 (ERK1/2) are members of the mitogen-activated protein kinase [MAPK] family. Upon stimulation, these kinases translocate from the cytoplasm to the nucleus, where they induce physiological processes such as proliferation and differentiation. The mechanism of translocation of this kinase involves phosphorylation of two Ser residues within a nuclear translocation signal (NTS), which allows binding to importin7 and a subsequent penetration via nuclear pores. Here we show that the phosphorylation of both Ser residues is mediated mainly by casein kinase 2 (CK2) and that active ERK may assist in the phosphorylation of the N-terminal Ser. We also demonstrate that the phosphorylation is dependent on the release of ERK from cytoplasmic anchoring proteins. Crystal structure of the phosphomimetic ERK revealed that the NTS phosphorylation creates an acidic patch in ERK. Our model is that in resting cells ERK is bound to cytoplasmic anchors, which prevent its NTS phosphorylation. Upon stimulation, phosphorylation of the ERK TEY domain releases ERK and allows phosphorylation of its NTS by CK2 and active ERK to generate a negatively charged patch in ERK, binding to importin 7 and nuclear translocation. These results provide an important role of CK2 in regulating nuclear ERK activities.
Collapse
|
27
|
Nuclear envelope structural defects cause chromosomal numerical instability and aneuploidy in ovarian cancer. BMC Med 2011; 9:28. [PMID: 21439080 PMCID: PMC3072346 DOI: 10.1186/1741-7015-9-28] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/26/2011] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Despite our substantial understanding of molecular mechanisms and gene mutations involved in cancer, the technical approaches for diagnosis and prognosis of cancer are limited. In routine clinical diagnosis of cancer, the procedure is very basic: nuclear morphology is used as a common assessment of the degree of malignancy, and hence acts as a prognostic and predictive indicator of the disease. Furthermore, though the atypical nuclear morphology of cancer cells is believed to be a consequence of oncogenic signaling, the molecular basis remains unclear. Another common characteristic of human cancer is aneuploidy, but the causes and its role in carcinogenesis are not well established. METHODS We investigated the expression of the nuclear envelope proteins lamin A/C in ovarian cancer by immunohistochemistry and studied the consequence of lamin A/C suppression using siRNA in primary human ovarian surface epithelial cells in culture. We used immunofluorescence microscopy to analyze nuclear morphology, flow cytometry to analyze cellular DNA content, and fluorescence in situ hybridization to examine cell ploidy of the lamin A/C-suppressed cells. RESULTS We found that nuclear lamina proteins lamin A/C are often absent (47%) in ovarian cancer cells and tissues. Even in lamin A/C-positive ovarian cancer, the expression is heterogeneous within the population of tumor cells. In most cancer cell lines, a significant fraction of the lamin A/C-negative population was observed to intermix with the lamin A/C-positive cells. Down regulation of lamin A/C in non-cancerous primary ovarian surface epithelial cells led to morphological deformation and development of aneuploidy. The aneuploid cells became growth retarded due to a p53-dependent induction of the cell cycle inhibitor p21. CONCLUSIONS We conclude that the loss of nuclear envelope structural proteins, such as lamin A/C, may underlie two of the hallmarks of cancer--aberrations in nuclear morphology and aneuploidy.
Collapse
|