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Casacuberta-Serra S, González-Larreategui Í, Capitán-Leo D, Soucek L. MYC and KRAS cooperation: from historical challenges to therapeutic opportunities in cancer. Signal Transduct Target Ther 2024; 9:205. [PMID: 39164274 PMCID: PMC11336233 DOI: 10.1038/s41392-024-01907-z] [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: 01/12/2024] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 08/22/2024] Open
Abstract
RAS and MYC rank amongst the most commonly altered oncogenes in cancer, with RAS being the most frequently mutated and MYC the most amplified. The cooperative interplay between RAS and MYC constitutes a complex and multifaceted phenomenon, profoundly influencing tumor development. Together and individually, these two oncogenes regulate most, if not all, hallmarks of cancer, including cell death escape, replicative immortality, tumor-associated angiogenesis, cell invasion and metastasis, metabolic adaptation, and immune evasion. Due to their frequent alteration and role in tumorigenesis, MYC and RAS emerge as highly appealing targets in cancer therapy. However, due to their complex nature, both oncogenes have been long considered "undruggable" and, until recently, no drugs directly targeting them had reached the clinic. This review aims to shed light on their complex partnership, with special attention to their active collaboration in fostering an immunosuppressive milieu and driving immunotherapeutic resistance in cancer. Within this review, we also present an update on the different inhibitors targeting RAS and MYC currently undergoing clinical trials, along with their clinical outcomes and the different combination strategies being explored to overcome drug resistance. This recent clinical development suggests a paradigm shift in the long-standing belief of RAS and MYC "undruggability", hinting at a new era in their therapeutic targeting.
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Affiliation(s)
| | - Íñigo González-Larreategui
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain
| | - Daniel Capitán-Leo
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain
| | - Laura Soucek
- Peptomyc S.L., Barcelona, Spain.
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
- Department of Biochemistry and Molecular Biology, Universitat Autonoma de Barcelona, Bellaterra, Spain.
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2
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Chen W, Hu Z, Guo Z. Targeting CD24 in Cancer Immunotherapy. Biomedicines 2023; 11:3159. [PMID: 38137380 PMCID: PMC10740697 DOI: 10.3390/biomedicines11123159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/19/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Immunotherapy is a hot area in cancer treatment, and one of the keys to this therapy is the identification of the right tumour-associated or tumour-specific antigen. Cluster of differentiation 24 (CD24) is an emerging tumour-associated antigen that is commonly and highly expressed in various tumours. In addition, CD24 is associated with several cancer-related signalling pathways and closely interacts with other molecules and immune cells to influence tumour progression. Monoclonal antibodies, antibody-drug conjugates (ADCs), chimeric antigen receptor (CAR) T-cell therapy, and CAR-NK cell therapy are currently available for the treatment of CD24. In this review, we summarise the existing therapeutic approaches and possible future directions targeting CD24.
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Affiliation(s)
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China;
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China;
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3
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Zhu S, Quan C, Wang R, Liang D, Su S, Rong P, Zhou K, Yang X, Chen Q, Li M, Du Q, Zhang J, Fang L, Wang HY, Chen S. The RalGAPα1-RalA signal module protects cardiac function through regulating calcium homeostasis. Nat Commun 2022; 13:4278. [PMID: 35879328 PMCID: PMC9314365 DOI: 10.1038/s41467-022-31992-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 07/07/2022] [Indexed: 11/09/2022] Open
Abstract
Sarcoplasmic/endoplasmic reticulum calcium ATPase SERCA2 mediates calcium re-uptake from the cytosol into sarcoplasmic reticulum, and its dysfunction is a hallmark of heart failure. Multiple factors have been identified to modulate SERCA2 activity, however, its regulation is still not fully understood. Here we identify a Ral-GTPase activating protein RalGAPα1 as a critical regulator of SERCA2 in cardiomyocytes through its downstream target RalA. RalGAPα1 is induced by pressure overload, and its deficiency causes cardiac dysfunction and exacerbates pressure overload-induced heart failure. Mechanistically, RalGAPα1 regulates SERCA2 through direct interaction and its target RalA. Deletion of RalGAPα1 decreases SERCA2 activity and prolongs calcium re-uptake into sarcoplasmic reticulum. GDP-bound RalA, but not GTP-bound RalA, binds to SERCA2 and activates the pump for sarcoplasmic reticulum calcium re-uptake. Overexpression of a GDP-bound RalAS28N mutant in the heart preserves cardiac function in a mouse model of heart failure. Our findings have therapeutic implications for treatment of heart failure.
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Affiliation(s)
- Sangsang Zhu
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Chao Quan
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Ruizhen Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Derong Liang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Shu Su
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Ping Rong
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Kun Zhou
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Xinyu Yang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Qiaoli Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Min Li
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Qian Du
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Jingzi Zhang
- School of Medicine, Nanjing University, Nanjing, China
| | - Lei Fang
- School of Medicine, Nanjing University, Nanjing, China
| | - Hong-Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China.
| | - Shuai Chen
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Model Animal Research Center, Nanjing University, Nanjing, China.
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4
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Antitumor Effects of Ral-GTPases Downregulation in Glioblastoma. Int J Mol Sci 2022; 23:ijms23158199. [PMID: 35897776 PMCID: PMC9330696 DOI: 10.3390/ijms23158199] [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: 06/29/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 12/20/2022] Open
Abstract
Glioblastoma (GBM) is the most common tumor in the central nervous system in adults. This neoplasia shows a high capacity of growth and spreading to the surrounding brain tissue, hindering its complete surgical resection. Therefore, the finding of new antitumor therapies for GBM treatment is a priority. We have previously described that cyclin D1-CDK4 promotes GBM dissemination through the activation of the small GTPases RalA and RalB. In this paper, we show that RalB GTPase is upregulated in primary GBM cells. We found that the downregulation of Ral GTPases, mainly RalB, prevents the proliferation of primary GBM cells and triggers a senescence-like response. Moreover, downregulation of RalA and RalB reduces the viability of GBM cells growing as tumorspheres, suggesting a possible role of these GTPases in the survival of GBM stem cells. By using mouse subcutaneous xenografts, we have corroborated the role of RalB in GBM growth in vivo. Finally, we have observed that the knockdown of RalB also inhibits cell growth in temozolomide-resistant GBM cells. Overall, our work shows that GBM cells are especially sensitive to Ral-GTPase availability. Therefore, we propose that the inactivation of Ral-GTPases may be a reliable therapeutic approach to prevent GBM progression and recurrence.
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Minemura C, Asai S, Koma A, Kase-Kato I, Tanaka N, Kikkawa N, Kasamatsu A, Yokoe H, Hanazawa T, Uzawa K, Seki N. Identification of Tumor-Suppressive miR-30e-3p Targets: Involvement of SERPINE1 in the Molecular Pathogenesis of Head and Neck Squamous Cell Carcinoma. Int J Mol Sci 2022; 23:ijms23073808. [PMID: 35409173 PMCID: PMC8998321 DOI: 10.3390/ijms23073808] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/13/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
Recently, our studies revealed that some passenger strands of microRNAs (miRNAs) were closely involved in cancer pathogenesis. Analysis of miRNA expression signatures showed that the expression of miR-30e-3p (the passenger strand of pre-miR-30e) was significantly downregulated in cancer tissues. In this study, we focused on miR-30e-3p (the passenger strand of pre-miR-30e). We addressed target genes controlled by miR-30e-3p that were closely associated with the molecular pathogenesis of head and neck squamous cell carcinoma (HNSCC). Ectopic expression assays demonstrated that the expression of miR-30e-3p attenuated cancer cell malignant phenotypes (e.g., cell proliferation, migration, and invasive abilities). Our analysis of miR-30e-3p targets revealed that 11 genes (ADA, CPNE8, C14orf126, ERGIC2, HMGA2, PLS3, PSMD10, RALB, SERPINE1, SFXN1, and TMEM87B) were expressed at high levels in HNSCC patients. Moreover, they significantly predicted the short survival of HNSCC patients based on 5-year overall survival rates (p < 0.05) in The Cancer Genome Atlas (TCGA). Among these targets, SERPINE1 was found to be an independent prognostic factor for patient survival (multivariate Cox regression; hazard ratio = 1.6078, p < 0.05). Aberrant expression of SERPINE1 was observed in HNSCC clinical samples by immunohistochemical analysis. Functional assays by targeting SERPINE1 expression revealed that the malignant phenotypes (e.g., proliferation, migration, and invasion abilities) of HNSCC cells were suppressed by the silencing of SERPINE1 expression. Our miRNA-based approach will accelerate our understanding of the molecular pathogenesis of HNSCC.
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Affiliation(s)
- Chikashi Minemura
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
- Department of Oral and Maxillofacial Surgery, National Defense Medical College Hospital, Tokorozawa 359-8513, Japan;
| | - Shunichi Asai
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan; (S.A.); (N.K.)
- Department of Otorhinolaryngology/Head and Neck Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan;
| | - Ayaka Koma
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
| | - Ikuko Kase-Kato
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
| | - Nozomi Tanaka
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
| | - Naoko Kikkawa
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan; (S.A.); (N.K.)
- Department of Otorhinolaryngology/Head and Neck Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan;
| | - Atsushi Kasamatsu
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
| | - Hidetaka Yokoe
- Department of Oral and Maxillofacial Surgery, National Defense Medical College Hospital, Tokorozawa 359-8513, Japan;
| | - Toyoyuki Hanazawa
- Department of Otorhinolaryngology/Head and Neck Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan;
| | - Katsuhiro Uzawa
- Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan; (C.M.); (A.K.); (I.K.-K.); (N.T.); (A.K.); (K.U.)
| | - Naohiko Seki
- Department of Functional Genomics, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan; (S.A.); (N.K.)
- Correspondence: ; Tel.: +81-43-226-2971; Fax: +81-43-227-3442
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6
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Small-Molecule RAS Inhibitors as Anticancer Agents: Discovery, Development, and Mechanistic Studies. Int J Mol Sci 2022; 23:ijms23073706. [PMID: 35409064 PMCID: PMC8999084 DOI: 10.3390/ijms23073706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 12/11/2022] Open
Abstract
Mutations of RAS oncogenes are responsible for about 30% of all human cancer types, including pancreatic, lung, and colorectal cancers. While KRAS1 is a pseudogene, mutation of KRAS2 (commonly known as KRAS oncogene) is directly or indirectly associated with human cancers. Among the RAS family, KRAS is the most abundant oncogene related to uncontrolled cellular proliferation to generate solid tumors in many types of cancer such as pancreatic carcinoma (over 80%), colon carcinoma (40-50%), lung carcinoma (30-50%), and other types of cancer. Once described as 'undruggable', RAS proteins have become 'druggable', at least to a certain extent, due to the continuous efforts made during the past four decades. In this account, we discuss the chemistry and biology (wherever available) of the small-molecule inhibitors (synthetic, semi-synthetic, and natural) of KRAS proteins that were published in the past decades. Commercial drugs, as well as investigational molecules from preliminary stages to clinical trials, are categorized and discussed in this study. In summary, this study presents an in-depth discussion of RAS proteins, classifies the RAS superfamily, and describes the molecular mechanism of small-molecule RAS inhibitors.
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7
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Hurd CA, Brear P, Revell J, Ross S, Mott HR, Owen D. Affinity maturation of the RLIP76 Ral binding domain to inform the design of stapled peptides targeting the Ral GTPases. J Biol Chem 2021; 296:100101. [PMID: 33214225 PMCID: PMC7949049 DOI: 10.1074/jbc.ra120.015735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/10/2020] [Accepted: 11/19/2020] [Indexed: 12/18/2022] Open
Abstract
Ral GTPases have been implicated as critical drivers of cell growth and metastasis in numerous Ras-driven cancers. We have previously reported stapled peptides, based on the Ral effector RLIP76, that can disrupt Ral signaling. Stapled peptides are short peptides that are locked into their bioactive form using a synthetic brace. Here, using an affinity maturation of the RLIP76 Ral-binding domain, we identified several sequence substitutions that together improve binding to Ral proteins by more than 20-fold. Hits from the selection were rigorously analyzed to determine the contributions of individual residues and two 1.5 Å cocrystal structures of the tightest-binding mutants in complex with RalB revealed key interactions. Insights gained from this maturation were used to design second-generation stapled peptides based on RLIP76 that exhibited vastly improved selectivity for Ral GTPases when compared with the first-generation lead peptide. The binding of second-generation peptides to Ral proteins was quantified and the binding site of the lead peptide on RalB was determined by NMR. Stapled peptides successfully competed with multiple Ral-effector interactions in cellular lysates. Our findings demonstrate how manipulation of a native binding partner can assist in the rational design of stapled peptide inhibitors targeting a protein-protein interaction.
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Affiliation(s)
- Catherine A Hurd
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Paul Brear
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jefferson Revell
- AstraZeneca, Sir Aaron Klug Building, Granta Park, Cambridge, UK
| | - Sarah Ross
- Research and Early Development, Oncology R&D, AstraZeneca, Cambridge, UK
| | - Helen R Mott
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
| | - Darerca Owen
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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Apken LH, Oeckinghaus A. The RAL signaling network: Cancer and beyond. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 361:21-105. [PMID: 34074494 DOI: 10.1016/bs.ircmb.2020.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The RAL proteins RALA and RALB belong to the superfamily of small RAS-like GTPases (guanosine triphosphatases). RAL GTPases function as molecular switches in cells by cycling through GDP- and GTP-bound states, a process which is regulated by several guanine exchange factors (GEFs) and two heterodimeric GTPase activating proteins (GAPs). Since their discovery in the 1980s, RALA and RALB have been established to exert isoform-specific functions in central cellular processes such as exocytosis, endocytosis, actin organization and gene expression. Consequently, it is not surprising that an increasing number of physiological functions are discovered to be controlled by RAL, including neuronal plasticity, immune response, and glucose and lipid homeostasis. The critical importance of RAL GTPases for oncogenic RAS-driven cellular transformation and tumorigenesis still attracts most research interest. Here, RAL proteins are key drivers of cell migration, metastasis, anchorage-independent proliferation, and survival. This chapter provides an overview of normal and pathological functions of RAL GTPases and summarizes the current knowledge on the involvement of RAL in human disease as well as current therapeutic targeting strategies. In particular, molecular mechanisms that specifically control RAL activity and RAL effector usage in different scenarios are outlined, putting a spotlight on the complexity of the RAL GTPase signaling network and the emerging theme of RAS-independent regulation and relevance of RAL.
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Affiliation(s)
- Lisa H Apken
- Institute of Molecular Tumor Biology, Faculty of Medicine, University of Münster, Münster, Germany
| | - Andrea Oeckinghaus
- Institute of Molecular Tumor Biology, Faculty of Medicine, University of Münster, Münster, Germany.
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Melick CH, Jewell JL. Regulation of mTORC1 by Upstream Stimuli. Genes (Basel) 2020; 11:genes11090989. [PMID: 32854217 PMCID: PMC7565831 DOI: 10.3390/genes11090989] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/22/2020] [Accepted: 08/23/2020] [Indexed: 01/08/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) is an evolutionary conserved Ser/Thr protein kinase that senses multiple upstream stimuli to control cell growth, metabolism, and autophagy. mTOR is the catalytic subunit of mTOR complex 1 (mTORC1). A significant amount of research has uncovered the signaling pathways regulated by mTORC1, and the involvement of these signaling cascades in human diseases like cancer, diabetes, and ageing. Here, we review advances in mTORC1 regulation by upstream stimuli. We specifically focus on how growth factors, amino acids, G-protein coupled receptors (GPCRs), phosphorylation, and small GTPases regulate mTORC1 activity and signaling.
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Affiliation(s)
- Chase H. Melick
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenna L. Jewell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Correspondence:
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Abstract
RAS was identified as a human oncogene in the early 1980s and subsequently found to be mutated in nearly 30% of all human cancers. More importantly, RAS plays a central role in driving tumor development and maintenance. Despite decades of effort, there remain no FDA approved drugs that directly inhibit RAS. The prevalence of RAS mutations in cancer and the lack of effective anti-RAS therapies stem from RAS' core role in growth factor signaling, unique structural features, and biochemistry. However, recent advances have brought promising new drugs to clinical trials and shone a ray of hope in the field. Here, we will exposit the details of RAS biology that illustrate its key role in cell signaling and shed light on the difficulties in therapeutically targeting RAS. Furthermore, past and current efforts to develop RAS inhibitors will be discussed in depth.
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Affiliation(s)
- J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States.
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11
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Beel S, Kolloch L, Apken LH, Jürgens L, Bolle A, Sudhof N, Ghosh S, Wardelmann E, Meisterernst M, Steinestel K, Oeckinghaus A. κB-Ras and Ral GTPases regulate acinar to ductal metaplasia during pancreatic adenocarcinoma development and pancreatitis. Nat Commun 2020; 11:3409. [PMID: 32641778 PMCID: PMC7343838 DOI: 10.1038/s41467-020-17226-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 06/16/2020] [Indexed: 12/12/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is associated with high mortality and therapy resistance. Here, we show that low expression of κB-Ras GTPases is frequently detected in PDAC and correlates with higher histologic grade. In a model of KRasG12D-driven PDAC, loss of κB-Ras accelerates tumour development and shortens median survival. κB-Ras deficiency promotes acinar-to-ductal metaplasia (ADM) during tumour initiation as well as tumour progression through intrinsic effects on proliferation and invasion. κB-Ras proteins are also required for acinar regeneration after pancreatitis, demonstrating a general role in control of plasticity. Molecularly, upregulation of Ral GTPase activity and Sox9 expression underlies the observed phenotypes, identifying a previously unrecognized function of Ral signalling in ADM. Our results provide evidence for a tumour suppressive role of κB-Ras proteins and highlight low κB-Ras levels and consequent loss of Ral control as risk factors, thus emphasizing the necessity for therapeutic options that allow interference with Ral-driven signalling. The molecular mechanisms of acinar-to-ductal metaplasia (ADM) in the course of pancreatitis and cancer development are unclear. Here, the authors show that loss of κB-Ras and consequent Ral activation promotes tumour initiation and progression through persistent ADM and enhanced cell proliferation
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Affiliation(s)
- Stephanie Beel
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Lina Kolloch
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Lisa H Apken
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Lara Jürgens
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Andrea Bolle
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Nadine Sudhof
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Sankar Ghosh
- Department of Microbiology & Immunology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Eva Wardelmann
- Gerhard-Domagk-Institute of Pathology, Faculty of Medicine, University Münster, Münster, Germany
| | - Michael Meisterernst
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany
| | - Konrad Steinestel
- Gerhard-Domagk-Institute of Pathology, Faculty of Medicine, University Münster, Münster, Germany.,Institute of Pathology and Molecular Pathology, Bundeswehrkrankenhaus Ulm, Ulm, Germany
| | - Andrea Oeckinghaus
- Institute of Molecular Tumorbiology, Faculty of Medicine, University Münster, Münster, Germany.
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12
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Venkat S, Tisdale AA, Schwarz JR, Alahmari AA, Maurer HC, Olive KP, Eng KH, Feigin ME. Alternative polyadenylation drives oncogenic gene expression in pancreatic ductal adenocarcinoma. Genome Res 2020; 30:347-360. [PMID: 32029502 PMCID: PMC7111527 DOI: 10.1101/gr.257550.119] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/04/2020] [Indexed: 01/08/2023]
Abstract
Alternative polyadenylation (APA) is a gene regulatory process that dictates mRNA 3'-UTR length, resulting in changes in mRNA stability and localization. APA is frequently disrupted in cancer and promotes tumorigenesis through altered expression of oncogenes and tumor suppressors. Pan-cancer analyses have revealed common APA events across the tumor landscape; however, little is known about tumor type-specific alterations that may uncover novel events and vulnerabilities. Here, we integrate RNA-sequencing data from the Genotype-Tissue Expression (GTEx) project and The Cancer Genome Atlas (TCGA) to comprehensively analyze APA events in 148 pancreatic ductal adenocarcinomas (PDACs). We report widespread, recurrent, and functionally relevant 3'-UTR alterations associated with gene expression changes of known and newly identified PDAC growth-promoting genes and experimentally validate the effects of these APA events on protein expression. We find enrichment for APA events in genes associated with known PDAC pathways, loss of tumor-suppressive miRNA binding sites, and increased heterogeneity in 3'-UTR forms of metabolic genes. Survival analyses reveal a subset of 3'-UTR alterations that independently characterize a poor prognostic cohort among PDAC patients. Finally, we identify and validate the casein kinase CSNK1A1 (also known as CK1alpha or CK1a) as an APA-regulated therapeutic target in PDAC. Knockdown or pharmacological inhibition of CSNK1A1 attenuates PDAC cell proliferation and clonogenic growth. Our single-cancer analysis reveals APA as an underappreciated driver of protumorigenic gene expression in PDAC via the loss of miRNA regulation.
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Affiliation(s)
- Swati Venkat
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
| | - Arwen A Tisdale
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
| | - Johann R Schwarz
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
| | - Abdulrahman A Alahmari
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
| | - H Carlo Maurer
- Klinikum rechts der Isar, II. Medizinische Klinik, Technische Universität München, 81675 Munich, Germany
| | - Kenneth P Olive
- Herbert Irving Comprehensive Cancer Center, Department of Medicine, Division of Digestive and Liver Diseases, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York 10032, USA
| | - Kevin H Eng
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
| | - Michael E Feigin
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, USA
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Down-regulation of RalGTPase-Activating Protein Promotes Colitis-Associated Cancer via NLRP3 Inflammasome Activation. Cell Mol Gastroenterol Hepatol 2019; 9:277-293. [PMID: 31622786 PMCID: PMC6957823 DOI: 10.1016/j.jcmgh.2019.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND & AIMS Ral guanosine triphosphatase-activating protein α2 (RalGAPα2) is the major catalytic subunit of the negative regulators of the small guanosine triphosphatase Ral, a member of the Ras subfamily. Ral regulates tumorigenesis and invasion/metastasis of some cancers; however, the role of Ral in colitis-associated cancer (CAC) has not been investigated. We aimed to elucidate the role of Ral in the mechanism of CAC. METHODS We used wild-type (WT) mice and RalGAPα2 knockout (KO) mice that showed Ral activation, and bone marrow chimeric mice were generated as follows: WT to WT, WT to RalGAPα2 KO, RalGAPα2 KO to WT, and RalGAPα2 KO to RalGAPα2 KO mice. CAC was induced in these mice by intraperitoneal injection of azoxymethane followed by dextran sulfate sodium intake. Intestinal epithelial cells were isolated from colon tissues, and we performed complementary DNA microarray analysis. Cytokine expression in normal colon tissues and CAC was analyzed by quantitative polymerase chain reaction. RESULTS Bone marrow chimeric mice showed that immune cell function between WT mice and RalGAPα2 KO mice was not significantly different in the CAC mechanism. RalGAPα2 KO mice had a significantly larger tumor number and size and a significantly higher proportion of tumors invading the submucosa than WT mice. Higher expression levels of matrix metalloproteinase-9 and matrix metalloproteinase-13 were observed in RalGAPα2 KO mice than in WT mice. The expression levels of interleukin 1β, NLRP3, apoptosis associated speck-like protein containing a CARD, and caspase-1 were apparently increased in the tumors of RalGAPα2 KO mice compared with WT mice. NLRP3 inhibitor reduced the number of invasive tumors. CONCLUSIONS Ral activation participates in the mechanism of CAC development via NLRP3 inflammasome activation.
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14
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Ommer A, Figlia G, Pereira JA, Datwyler AL, Gerber J, DeGeer J, Lalli G, Suter U. Ral GTPases in Schwann cells promote radial axonal sorting in the peripheral nervous system. J Cell Biol 2019; 218:2350-2369. [PMID: 31201267 PMCID: PMC6605813 DOI: 10.1083/jcb.201811150] [Citation(s) in RCA: 11] [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: 11/28/2018] [Revised: 04/03/2019] [Accepted: 05/15/2019] [Indexed: 12/11/2022] Open
Abstract
Small GTPases of the Rho and Ras families are important regulators of Schwann cell biology. The Ras-like GTPases RalA and RalB act downstream of Ras in malignant peripheral nerve sheath tumors. However, the physiological role of Ral proteins in Schwann cell development is unknown. Using transgenic mice with ablation of one or both Ral genes, we report that Ral GTPases are crucial for axonal radial sorting. While lack of only one Ral GTPase was dispensable for early peripheral nerve development, ablation of both RalA and RalB resulted in persistent radial sorting defects, associated with hallmarks of deficits in Schwann cell process formation and maintenance. In agreement, ex vivo-cultured Ral-deficient Schwann cells were impaired in process extension and the formation of lamellipodia. Our data indicate further that RalA contributes to Schwann cell process extensions through the exocyst complex, a known effector of Ral GTPases, consistent with an exocyst-mediated function of Ral GTPases in Schwann cells.
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Affiliation(s)
- Andrea Ommer
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Gianluca Figlia
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Jorge A Pereira
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Anna Lena Datwyler
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Joanne Gerber
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Jonathan DeGeer
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Giovanna Lalli
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
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15
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Gong S, Chen Y, Meng F, Zhang Y, Wu H, Li C, Zhang G. RCC2, a regulator of the RalA signaling pathway, is identified as a novel therapeutic target in cisplatin-resistant ovarian cancer. FASEB J 2019; 33:5350-5365. [PMID: 30768358 DOI: 10.1096/fj.201801529rr] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Currently, cisplatin (DDP) is the first-line chemotherapeutic agent used for treatment of ovarian cancer, but gradually acquired drug resistance minimizes its therapeutic outcomes. We aimed to identify crucial genes associated with DDP resistance in ovarian cancer and uncover potential mechanisms. Two sets of gene expression data were downloaded from Gene Expression Omnibus, and bioinformatics analysis was conducted. In our study, the differentially expressed genes between DDP-sensitive and DDP-resistant ovarian cancer were screened in GSE15709 and GSE51373 database, and chromosome condensation 2 regulator (RCC2) and nucleoporin 160 were identified as 2 genes that significantly up-regulated in DDP-resistant ovarian cancer cell lines compared with DDP-sensitive cell lines. Moreover, RCC2, Ral small GTPase (RalA), and Ral binding protein-1 (RalBP1) expression was found to be significantly higher in DDP-resistant ovarian cancer tissues than in DDP-sensitive tissues. RCC2 plays a positive role in cell proliferation, apoptosis, and migration in DDP-resistant ovarian cancer cell lines in vitro and in vivo. Furthermore, RCC2 could interact with RalA, thus promoting its downstream effector RalBP1. RalA knockdown could reverse the effects of RCC2 overexpression on DDP-resistant ovarian cancer cell proliferation, apoptosis, and migration. Similarly, RalA overexpression could alleviate the effects of RCC2 knockdown in DDP-resistant ovarian cancer cells. Taken together, RCC2 may function as an oncogene, regulating the RalA signaling pathway, and intervention of RCC2 expression might be a promising therapeutic strategy for DDP-resistant ovarian cancer.-Gong, S., Chen, Y., Meng, F., Zhang, Y., Wu, H., Li, C., Zhang, G. RCC2, a regulator of the RalA signaling pathway, is identified as a novel therapeutic target in cisplatin-resistant ovarian cancer.
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Affiliation(s)
- Shipeng Gong
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yongning Chen
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Fanliang Meng
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yadi Zhang
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Huan Wu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China; and
| | - Chanyuan Li
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Guangping Zhang
- Department of Gynecology, People's Hospital of Huadu District, Guangzhou, China
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Tripathi K, Garg M. Mechanistic regulation of epithelial-to-mesenchymal transition through RAS signaling pathway and therapeutic implications in human cancer. J Cell Commun Signal 2018; 12:513-527. [PMID: 29330773 PMCID: PMC6039341 DOI: 10.1007/s12079-017-0441-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/07/2017] [Indexed: 02/06/2023] Open
Abstract
RAS effector signaling instead of being simple, unidirectional and linear cascade, is actually recognized as highly complex and dynamic signaling network. RAF-MEK-ERK cascade, being at the center of complex signaling network, links to multiple scaffold proteins through feed forward and feedback mechanisms and dynamically regulate tumor initiation and progression. Three isoforms of Ras harbor mutations in a cell and tissue specific manner. Besides mutations, their epigenetic silencing also attributes them to exhibit oncogenic activities. Recent evidences support the functions of RAS oncoproteins in the acquisition of tumor cells with Epithelial-to-mesenchymal transition (EMT) features/ epithelial plasticity, enhanced metastatic potential and poor patient survival. Google Scholar electronic databases and PubMed were searched for original papers and reviews available till date to collect information on stimulation of EMT core inducers in a Ras driven cancer and their regulation in metastatic spread. Improved understanding of the mechanistic basis of regulatory interactions of microRNAs (miRs) and EMT by reprogramming the expression of targets in Ras activated cancer, may help in designing effective anticancer therapies. Apparent lack of adverse events associated with the delivery of miRs and tissue response make 'drug target miRNA' an ideal therapeutic tool to achieve progression free clinical response.
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Affiliation(s)
- Kiran Tripathi
- Department of Biochemistry, University of Lucknow, Lucknow, 226007, India
| | - Minal Garg
- Department of Biochemistry, University of Lucknow, Lucknow, 226007, India.
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17
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KRAS-Mutant non-small cell lung cancer: From biology to therapy. Lung Cancer 2018; 124:53-64. [PMID: 30268480 DOI: 10.1016/j.lungcan.2018.07.013] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/09/2018] [Accepted: 07/11/2018] [Indexed: 12/30/2022]
Abstract
In patients with non-small cell lung cancer (NSCLC), the most frequent oncogene driver mutation in Western countries is Kirsten rat sarcoma viral oncogene homolog (KRAS), and KRAS-mutant NSCLC is associated with smoking. There are various sources of biological heterogeneity of KRAS-mutant NSCLC, including different genotypes that may be associated with specific clinical outcomes, the presence of other co-mutations that exhibit different biological features and drug sensitivity patterns, and mutant allelic content. The efficacy of chemotherapy in patients with KRAS-mutant NSCLC is generally poor and numerous novel therapeutic strategies have been developed. These approaches include targeting KRAS membrane associations, targeting downstream signalling pathways, the use of KRAS synthetic lethality, direct targeting of KRAS, and immunotherapy. Of these, immunotherapy may be one of the most promising treatment approaches for patients with KRAS-mutant NSCLC. Recent data also suggest the potential for distinct efficacy of immunotherapy according to the presence of other co-mutations. In view of the biological heterogeneity of KRAS-mutant NSCLC, treatment will likely need to be individualised and, in future, may require the use of rational combinations of treatment, many of which are currently under investigation.
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18
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Inchanalkar S, Deshpande NU, Kasherwal V, Jayakannan M, Balasubramanian N. Polymer Nanovesicle-Mediated Delivery of MLN8237 Preferentially Inhibits Aurora Kinase A To Target RalA and Anchorage-Independent Growth in Breast Cancer Cells. Mol Pharm 2018; 15:3046-3059. [PMID: 29863884 DOI: 10.1021/acs.molpharmaceut.8b00163] [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] [Indexed: 12/20/2022]
Abstract
The small GTPase RalA is a known mediator of anchorage-independent growth in cancers and is differentially regulated by adhesion and aurora kinase A (AURKA). Hence, inhibiting AURKA offers a means of specifically targeting RalA (over RalB) in cancer cells. MLN8237 (alisertib) is a known inhibitor of aurora kinases; its specificity for AURKA, however, is compromised by its poor solubility and transport across the cell membrane. A polymer nanovesicle platform is used for the first time to deliver and differentially inhibit AURKA in cancer cells. For this purpose, polysaccharide nanovesicles made from amphiphilic dextran were used as nanocarriers to successfully administer MLN8237 (VMLN) in cancer cells in 2D and 3D microenvironments. These nanovesicles (<200 nm) carry the drug in their intermembrane space with up to 85% of it released by the action of esterase enzyme(s). Lysotracker experiments reveal the polymer nanovesicles localize in the lysosomal compartment of the cell, where they are enzymatically targeted and MLN released in a controlled manner. Rhodamine B fluorophore trapped in the nanovesicles hydrophilic core (VMLN+RhB) allows us to visualize its uptake and localization in cells in a 2D and 3D microenvironment. In breast cancer, MCF-7 cells VMLN inhibits AURKA significantly better than the free drug at low concentrations (0.02-0.04 μM). This ensures that the drug in VMLN at these concentrations can specifically inhibit up to 94% of endogenous AURKA without affecting AURKB. This targeting of AURKA causes the downstream differential inhibition of active RalA (but not RalB). Free MLN8237 at similar concentrations and conditions failed to affect RalA activation. VMLN-mediated inhibition of RalA, in turn, disrupts the anchorage-independent growth of MCF-7 cells supporting a role for the AURKA-RalA crosstalk in mediating the same. These studies not only identify the polysaccharide nanovesicle to be an improved way to efficiently deliver low concentrations of MLN8237 to inhibit AURKA but, in doing so, also help reveal a role for AURKA and its crosstalk with RalA in anchorage-independent growth of MCF-7 cells.
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Abstract
More than a hundred proteins comprise the RAS superfamily of small GTPases. This family can be divided into RAS, RHO, RAB, RAN, ARF, and RAD subfamilies, with each shown to play distinct roles in human cells in both health and disease. The RAS subfamily has a well-established role in human cancer with the three genes, HRAS, KRAS, and NRAS being the commonly mutated in tumors. These RAS mutations, most often functionally activating, are especially common in pancreatic, lung, and colorectal cancers. Efforts to inhibit RAS and related GTPases have produced inhibitors targeting the downstream effectors of RAS signaling, including inhibitors of the RAF-mitogen-activated protein kinase/extracellular signal-related kinase (ERK)-ERK kinase pathway and the phosphoinositide-3-kinase-AKT-mTOR kinase pathway. A third effector arm of RAS signaling, mediated by RAL (RAS like) has emerged in recent years as a critical driver of RAS oncogenic signaling and has not been targeted until recently. RAL belongs to the RAS branch of the RAS superfamily and shares a high structural similarity with RAS. In human cells, there are two genes, RALA and RALB, both of which have been shown to play roles in the proliferation, survival, and metastasis of a variety of human cancers, including lung, colon, pancreatic, prostate, skin, and bladder cancers. In this review, we summarize the latest knowledge of RAL in the context of human cancer and the recent advancements in the development of cancer therapeutics targeting RAL small GTPases.
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Affiliation(s)
- Chao Yan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China (C.Y.); Departments of Surgery (Urology) and Pharmacology, University of Colorado, Aurora, Colorado (D.T.); and University of Colorado Comprehensive Cancer Center, Aurora, Colorado (D.T.)
| | - Dan Theodorescu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China (C.Y.); Departments of Surgery (Urology) and Pharmacology, University of Colorado, Aurora, Colorado (D.T.); and University of Colorado Comprehensive Cancer Center, Aurora, Colorado (D.T.)
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20
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Moghadam AR, Patrad E, Tafsiri E, Peng W, Fangman B, Pluard TJ, Accurso A, Salacz M, Shah K, Ricke B, Bi D, Kimura K, Graves L, Najad MK, Dolatkhah R, Sanaat Z, Yazdi M, Tavakolinia N, Mazani M, Amani M, Ghavami S, Gartell R, Reilly C, Naima Z, Esfandyari T, Farassati F. Ral signaling pathway in health and cancer. Cancer Med 2017; 6:2998-3013. [PMID: 29047224 PMCID: PMC5727330 DOI: 10.1002/cam4.1105] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 04/10/2017] [Accepted: 04/14/2017] [Indexed: 12/12/2022] Open
Abstract
The Ral (Ras-Like) signaling pathway plays an important role in the biology of cells. A plethora of effects is regulated by this signaling pathway and its prooncogenic effectors. Our team has demonstrated the overactivation of the RalA signaling pathway in a number of human malignancies including cancers of the liver, ovary, lung, brain, and malignant peripheral nerve sheath tumors. Additionally, we have shown that the activation of RalA in cancer stem cells is higher in comparison with differentiated cancer cells. In this article, we review the role of Ral signaling in health and disease with a focus on the role of this multifunctional protein in the generation of therapies for cancer. An improved understanding of this pathway can lead to development of a novel class of anticancer therapies that functions on the basis of intervention with RalA or its downstream effectors.
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Affiliation(s)
- Adel Rezaei Moghadam
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegCanada
| | - Elham Patrad
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Elham Tafsiri
- Department of Pediatrics, Columbia Presbyterian Medical CenterNew YorkNew York
| | - Warner Peng
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Benjamin Fangman
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Timothy J Pluard
- Saint Luke's HospitalUniversity of Missouri at Kansas CityKansas CityMissouri
| | - Anthony Accurso
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Michael Salacz
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Kushal Shah
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Brandon Ricke
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Danse Bi
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Kyle Kimura
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Leland Graves
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Marzieh Khajoie Najad
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Roya Dolatkhah
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Zohreh Sanaat
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Mina Yazdi
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Naeimeh Tavakolinia
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Mohammad Mazani
- Pasteur Institute of IranTehranIran
- Ardabil University of Medical Sciences, BiochemistryArdabilIran
| | - Mojtaba Amani
- Pasteur Institute of IranTehranIran
- Ardabil University of Medical Sciences, BiochemistryArdabilIran
| | - Saeid Ghavami
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegCanada
| | - Robyn Gartell
- Department of Pediatrics, Columbia Presbyterian Medical CenterNew YorkNew York
| | - Colleen Reilly
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Zaid Naima
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Tuba Esfandyari
- Department of Medicine, Molecular Medicine LaboratoryThe University of Kansas Medical SchoolKansas CityKansas
| | - Faris Farassati
- Research Service (151)Kansas City Veteran Affairs Medical Center & Midwest Biomedical Research Foundation4801 E Linwood BlvdKansas CityMissouri64128‐2226
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Pomeroy EJ, Eckfeldt CE. Targeting Ras signaling in AML: RALB is a small GTPase with big potential. Small GTPases 2017; 11:39-44. [PMID: 28682649 DOI: 10.1080/21541248.2017.1339765] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acute myeloid leukemia (AML) is a devastating malignancy for which novel treatment approaches are desperately needed. Ras signaling is an attractive therapeutic target for AML because a large proportion of AMLs have mutations in NRAS, KRAS, or genes that activate Ras signaling, and key Ras effectors are activated in virtually all AML patient samples. This has inspired efforts to develop Ras-targeted treatment strategies for AML. Due to the inherent difficulty and disappointing efficacy of targeting Ras proteins directly, many have focused on inhibiting Ras effector pathways. Inhibiting the major oncogenic Ras effectors, the mitogen-activated protein kinase (MAPK) and/or phosphatidylinositiol-3-kinase (PI3K) pathways, has generally demonstrated modest efficacy for AML. While this may be in part related to functional redundancy between these pathways, it is now clear that other Ras effectors have key oncogenic roles. Specifically, the Ras-like (Ral) GTPases have emerged as critical mediators of Ras-driven transformation and AML cell survival. Our group recently uncovered a critical role for RALB signaling in leukemic cell survival and a potential mediator of relapse following Ras-targeted therapy in AML. Furthermore, we found that RALB signaling is hyperactivated in AML patient samples, and inhibiting RALB has potent anti-leukemic activity in preclinical AML models. While key questions remain regarding the importance of RALB signaling across the genetically diverse spectrum of AML, the specific mechanism(s) that promotes leukemic cell survival downstream of RALB, and how to pharmacologically target RALB signaling effectively - RALB has emerged as a critical Ras effector and potential therapeutic target for AML.
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Affiliation(s)
- Emily J Pomeroy
- Department of Medicine, Division of Hematology, Oncology, & Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Craig E Eckfeldt
- Department of Medicine, Division of Hematology, Oncology, & Transplantation, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
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22
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Negative Immune Regulator TIPE2 Promotes M2 Macrophage Differentiation through the Activation of PI3K-AKT Signaling Pathway. PLoS One 2017; 12:e0170666. [PMID: 28122045 PMCID: PMC5266285 DOI: 10.1371/journal.pone.0170666] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 01/09/2017] [Indexed: 01/22/2023] Open
Abstract
Macrophages play important roles in the regulation of the innate and adaptive immune responses. Classically activated macrophages and alternatively activated macrophages are the two major forms of macrophages and have opposing functionalities. Tumor necrosis factor-α-induced protein 8-2 is expressed primarily by immune cells and negatively regulates type 1 innate and adaptive immune responses to maintain immune tolerance. While previous studies indicate that TIPE2 promotes M2 but inhibits M1 macrophage differentiation, the underlying molecular mechanism by which TIPE2 promotes M2 macrophage differentiation remains unclear. Our current study shows that TIPE2-deficient bone-marrow cells are defective in IL-4 induced M2 macrophage differentiation in vitro. Mechanistic studies revealed that TIPE2 promotes phosphoinositide metabolism and the activation of the down-stream AKT signaling pathway, which in turn leads to the expression of markers specific for M2 macrophages. In addition, our results showed that Tipe2-deficiency does not affect the activation of the JAK-STAT6 signaling pathway that also plays an important role during M2 macrophage differentiation. Taken together, these results indicate that TIPE2 promotes M2 macrophage differentiation through the activation of PI3K-AKT signaling pathway, and may play an important role during the resolution of inflammation, parasite control, as well as tissue repair.
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Distinct Roles for the N- and C-terminal Regions of M-Sec in Plasma Membrane Deformation during Tunneling Nanotube Formation. Sci Rep 2016; 6:33548. [PMID: 27629377 PMCID: PMC5024327 DOI: 10.1038/srep33548] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/30/2016] [Indexed: 01/07/2023] Open
Abstract
The tunneling nanotube (TNT) is a structure used for intercellular communication, and is a thin membrane protrusion mediating transport of various signaling molecules and cellular components. M-Sec has potent membrane deformation ability and induces TNT formation in cooperation with the Ral/exocyst complex. Here, we show that the N-terminal polybasic region of M-Sec directly binds phosphatidylinositol (4,5)-bisphosphate for its localization to the plasma membrane during the initial stage of TNT formation. We further report a crystal structure of M-Sec, which consists of helix bundles arranged in a straight rod-like shape, similar to the membrane tethering complex subunits. A positively charged surface in the C-terminal domains is required for M-Sec interaction with active RalA to extend the plasma membrane protrusions. Our results suggest that the membrane-associated M-Sec recruits active RalA, which directs the exocyst complex to form TNTs.
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24
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Thomas JC, Cooper JM, Clayton NS, Wang C, White MA, Abell C, Owen D, Mott HR. Inhibition of Ral GTPases Using a Stapled Peptide Approach. J Biol Chem 2016; 291:18310-25. [PMID: 27334922 DOI: 10.1074/jbc.m116.720243] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 01/31/2023] Open
Abstract
Aberrant Ras signaling drives numerous cancers, and drugs to inhibit this are urgently required. This compelling clinical need combined with recent innovations in drug discovery including the advent of biologic therapeutic agents, has propelled Ras back to the forefront of targeting efforts. Activated Ras has proved extremely difficult to target directly, and the focus has moved to the main downstream Ras-signaling pathways. In particular, the Ras-Raf and Ras-PI3K pathways have provided conspicuous enzyme therapeutic targets that were more accessible to conventional drug-discovery strategies. The Ras-RalGEF-Ral pathway is a more difficult challenge for traditional medicinal development, and there have, therefore, been few inhibitors reported that disrupt this axis. We have used our structure of a Ral-effector complex as a basis for the design and characterization of α-helical-stapled peptides that bind selectively to active, GTP-bound Ral proteins and that compete with downstream effector proteins. The peptides have been thoroughly characterized biophysically. Crucially, the lead peptide enters cells and is biologically active, inhibiting isoform-specific RalB-driven cellular processes. This, therefore, provides a starting point for therapeutic inhibition of the Ras-RalGEF-Ral pathway.
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Affiliation(s)
- Jemima C Thomas
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jonathan M Cooper
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390-9039
| | - Natasha S Clayton
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Chensu Wang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390-9039
| | - Michael A White
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas 75390-9039
| | - Chris Abell
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Darerca Owen
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom,
| | - Helen R Mott
- From the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom,
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RalGPS2 Is Essential for Survival and Cell Cycle Progression of Lung Cancer Cells Independently of Its Established Substrates Ral GTPases. PLoS One 2016; 11:e0154840. [PMID: 27149377 PMCID: PMC4858283 DOI: 10.1371/journal.pone.0154840] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 04/20/2016] [Indexed: 11/19/2022] Open
Abstract
The human genome contains six genes coding for proteins validated in vitro as specific activators of the small GTPases “Ras-related protein Ral-A” and “Ras-related protein Ral-B”, generically named Ral-guanine nucleotide exchange factors (RalGEF). Ral proteins are important contributors to Ras oncogenic signaling, and RAS oncogenes are important in human Non-Small Cell Lung Carcinoma (NSCLC). Therefore in this work, RalGEF contribution to oncogenic and non-oncogenic features of human NSCLC cell lines, as anchorage-dependent and independent growth, cell survival, and proliferation, was investigated. Among all human RalGEF, silencing of RGL1 and RALGPS1 had no detectable effect. However, silencing of either RGL2, RGL3, RALGDS or, to a larger extent, RALGPS2 inhibited cell population growth in anchorage dependent and independent conditions (up to 90 and 80%, respectively). RALGPS2 silencing also caused an increase in the number of apoptotic cells, up to 45% of the cell population in transformed bronchial BZR cells. In H1299 and A549, two NSCLC cell lines, RALGPS2 silencing caused an arrest of cells in the G0/G1-phase of cell cycle. Furthermore, it was associated with the modulation of important cell cycle regulators: the E3 Ubiquitin Protein Ligase S-phase kinase-associated protein 2 (Skp2) was strongly down-regulated (both at mRNA and protein levels), and its targets, the cell cycle inhibitors p27 and p21, were up-regulated. These molecular effects were not mimicked by silencing RALA, RALB, or both. However, RALB silencing caused a modest inhibition of cell cycle progression, which in H1299 cells was associated with Cyclin D1 regulation. In conclusion, RALGPS2 is implicated in the control of cell cycle progression and survival in the in vitro growth of NSCLC cell lines. This function is largely independent of Ral GTPases and associated with modulation of Skp2, p27 and p21 cell cycle regulators.
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26
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Modeling K-Ras-driven lung adenocarcinoma in mice: preclinical validation of therapeutic targets. J Mol Med (Berl) 2015; 94:121-35. [DOI: 10.1007/s00109-015-1360-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 10/22/2015] [Indexed: 01/10/2023]
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27
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Gentry LR, Nishimura A, Cox AD, Martin TD, Tsygankov D, Nishida M, Elston TC, Der CJ. Divergent roles of CAAX motif-signaled posttranslational modifications in the regulation and subcellular localization of Ral GTPases. J Biol Chem 2015. [PMID: 26216878 DOI: 10.1074/jbc.m115.656710] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Ras-like small GTPases RalA and RalB are well validated effectors of RAS oncogene-driven human cancer growth, and pharmacologic inhibitors of Ral function may provide an effective anti-Ras therapeutic strategy. Intriguingly, although RalA and RalB share strong overall amino acid sequence identity, exhibit essentially identical structural and biochemical properties, and can utilize the same downstream effectors, they also exhibit divergent and sometimes opposing roles in the tumorigenic and metastatic growth of different cancer types. These distinct biological functions have been attributed largely to sequence divergence in their carboxyl-terminal hypervariable regions. However, the role of posttranslational modifications signaled by the hypervariable region carboxyl-terminal tetrapeptide CAAX motif (C = cysteine, A = aliphatic amino acid, X = terminal residue) in Ral isoform-selective functions has not been addressed. We determined that these modifications have distinct roles and consequences. Both RalA and RalB require Ras converting CAAX endopeptidase 1 (RCE1) for association with the plasma membrane, albeit not with endomembranes, and loss of RCE1 caused mislocalization as well as sustained activation of both RalA and RalB. In contrast, isoprenylcysteine carboxylmethyltransferase (ICMT) deficiency disrupted plasma membrane localization only of RalB, whereas RalA depended on ICMT for efficient endosomal localization. Furthermore, the absence of ICMT increased stability of RalB but not RalA protein. Finally, palmitoylation was critical for subcellular localization of RalB but not RalA. In summary, we have identified striking isoform-specific consequences of distinct CAAX-signaled posttranslational modifications that contribute to the divergent subcellular localization and activity of RalA and RalB.
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Affiliation(s)
| | - Akiyuki Nishimura
- the Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, 5-1 Higashiyama, Myoudaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Adrienne D Cox
- From the Departments of Pharmacology and Radiation Oncology, and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and
| | | | | | - Motohiro Nishida
- the Division of Cardiocirculatory Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, 5-1 Higashiyama, Myoudaiji-cho, Okazaki, Aichi 444-8787, Japan
| | | | - Channing J Der
- From the Departments of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and
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Papini D, Langemeyer L, Abad MA, Kerr A, Samejima I, Eyers PA, Jeyaprakash AA, Higgins JMG, Barr FA, Earnshaw WC. TD-60 links RalA GTPase function to the CPC in mitosis. Nat Commun 2015; 6:7678. [PMID: 26158537 PMCID: PMC4510650 DOI: 10.1038/ncomms8678] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 05/29/2015] [Indexed: 12/26/2022] Open
Abstract
TD-60 (also known as RCC2) is a highly conserved protein that structurally resembles the Ran guanine exchange factor (GEF) RCC1, but has not previously been shown to have GEF activity. TD-60 has a typical chromosomal passenger complex (CPC) distribution in mitotic cells, but associates with integrin complexes and is involved in cell motility during interphase. Here we show that TD-60 exhibits GEF activity, in vitro and in cells, for the small GTPase RalA. TD-60 or RalA depletion causes spindle abnormalities in prometaphase associated with abnormal centromeric accumulation of CPC components. TD-60 and RalA apparently work together to contribute to the regulation of kinetochore-microtubule interactions in early mitosis. Importantly, several mitotic phenotypes caused by TD-60 depletion are reverted by the expression of a GTP-locked mutant, RalA (Q72L). The demonstration that a small GTPase participates in the regulation of the CPC reveals a level of mitotic regulation not suspected in previous studies.
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Affiliation(s)
- Diana Papini
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
- Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Lars Langemeyer
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Maria A. Abad
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Alastair Kerr
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Itaru Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Patrick A. Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown St, Liverpool L69 7ZB, UK
| | - A. Arockia Jeyaprakash
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Jonathan M. G. Higgins
- Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Francis A. Barr
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - William C. Earnshaw
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
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RalB regulates contractility-driven cancer dissemination upon TGFβ stimulation via the RhoGEF GEF-H1. Sci Rep 2015; 5:11759. [PMID: 26152517 PMCID: PMC4495419 DOI: 10.1038/srep11759] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/03/2015] [Indexed: 01/18/2023] Open
Abstract
RalA and RalB proteins are key mediators of oncogenic Ras signaling in human oncogenesis. Herein we investigated the mechanistic contribution of Ral proteins to invasion of lung cancer A549 cells after induction of epithelial-mesenchymal transition (EMT) with TGFβ. We show that TGFβ-induced EMT promotes dissemination of A549 cells in a 2/3D assay, independently of proteolysis, by activating the Rho/ROCK pathway which generates actomyosin-dependent contractility forces that actively remodel the extracellular matrix, as assessed by Traction Force microscopy. RalB, but not RalA, is required for matrix deformation and cell dissemination acting via the RhoGEF GEF-H1, which associates with the Exocyst complex, a major Ral effector. Indeed, uncoupling of the Exocyst subunit Sec5 from GEF-H1 impairs RhoA activation, generation of traction forces and cell dissemination. These results provide a novel molecular mechanism underlying the control of cell invasion by RalB via a cross-talk with the Rho pathway.
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30
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The RAS-RAL axis in cancer: evidence for mutation-specific selectivity in non-small cell lung cancer. Acta Pharmacol Sin 2015; 36:291-7. [PMID: 25557115 DOI: 10.1038/aps.2014.129] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/30/2014] [Indexed: 12/21/2022]
Abstract
Activating RAS mutations are common in human tumors. These mutations are often markers for resistance to therapy and subsequent poor prognosis. So far, targeting the RAF-MEK-ERK and PI3K-AKT signaling pathways downstream of RAS is the only promising approach in the treatment of cancer patients harboring RAS mutations. RAL GTPase, another downstream effector of RAS, is also considered as a therapeutic option for the treatment of RAS-mutant cancers. The RAL GTPase family comprises RALA and RALB, which can have either divergent or similar functions in different tumor models. Recent studies on non-small cell lung cancer (NSCLC) have showed that different RAS mutations selectively activate specific effector pathways. This observation requires broader validation in other tumor tissue types, but if true, will provide a new approach to the treatment of RAS-mutant cancer patients by targeting specific downstream RAS effectors according to the type of RAS mutation. It also suggests that RAL GTPase inhibition will be an important treatment strategy for tumors harboring RAS glycine to cysteine (G12C) or glycien to valine (G12V) mutations, which are commonly found in NSCLC and pancreatic cancer.
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31
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Campbell LJ, Peppa M, Crabtree MD, Shafiq A, McGough NF, Mott HR, Owen D. Thermodynamic mapping of effector protein interfaces with RalA and RalB. Biochemistry 2015; 54:1380-9. [PMID: 25621740 DOI: 10.1021/bi501530u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
RalA and RalB are members of the Ras family of small G proteins and are activated downstream of Ras via RalGEFs. The RalGEF-Ral axis represents one of the major effector pathways controlled by Ras and as such is an important pharmacological target. RalA and RalB are approximately 80% identical at the amino acid level; despite this, they have distinct roles both in normal cells and in the disease state. We have used our structure of RalB-RLIP76 to guide an analysis of Ral-effector interaction interfaces, creating panels of mutant proteins to probe the energetics of these interactions. The data provide a physical mechanism that underpins the effector selective mutations commonly employed to dissect Ral G protein function. Comparing the energetic landscape of the RalB-RLIP76 and RalB-Sec5 complexes reveals mutations in RalB that lead to differential binding of the two effector proteins. A panel of RLIP76 mutants was used to probe the interaction between RLIP76 and RalA and -B. Despite 100% sequence identity in the RalA and -B contact residues with RLIP76, differences still exist in the energetic profiles of the two complexes. Therefore, we have revealed properties that may account for some of the functional separation observed with RalA and RalB at the cellular level. Our mutations, in both the Ral isoforms and RLIP76, provide new tools that can be employed to parse the complex biology of Ral G protein signaling networks. The combination of these thermodynamic and structural data can also guide efforts to ablate RalA and -B activity with small molecules and peptides.
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Affiliation(s)
- Louise J Campbell
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge CB2 1GA, U.K
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32
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Kashatus DF, Counter CM. Breaking up is hard to do: RalA, mitochondrial fission and cancer. Small GTPases 2014; 2:329-333. [PMID: 22545232 PMCID: PMC3337163 DOI: 10.4161/sgtp.18284] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The small GTPases RalA and RalB are activated downstream of oncogenic Ras. While activation of RalA is critically important for tumor initiation and growth of Ras-driven cancers, the highly similar small GTPase RalB is implicated in cell survival and metastasis. This difference in function between these two related proteins maps to the C-terminus, a 30 amino acid region that regulates subcellular localization and contains several potential phosphorylation sites. Here we discuss our recent evidence that phosphorylation by the mitotic kinase Aurora A promotes RalA relocalization to mitochondrial membranes, where it recruits the effector RalBP1 and the large dynamin-related GTPase Drp1 to promote mitochondrial fission. As upregulation of both RalA and Aurora A have been observed in human tumors, and phosphorylation of RalA at the site targeted by Aurora A promotes tumorigenesis, it is possible that regulation of mitochondrial fission is one mechanism by which RalA promotes cancer.
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Affiliation(s)
- David F Kashatus
- Department of Pharmacology and Cancer Biology; Department of Radiation Oncology; Duke University Medical Center; Durham, NC USA
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33
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Cox AD, Der CJ. Ras history: The saga continues. Small GTPases 2014; 1:2-27. [PMID: 21686117 DOI: 10.4161/sgtp.1.1.12178] [Citation(s) in RCA: 542] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/17/2010] [Accepted: 05/24/2010] [Indexed: 12/24/2022] Open
Abstract
Although the roots of Ras sprouted from the rich history of retrovirus research, it was the discovery of mutationally activated RAS genes in human cancer in 1982 that stimulated an intensive research effort to understand Ras protein structure, biochemistry and biology. While the ultimate goal has been developing anti-Ras drugs for cancer treatment, discoveries from Ras have laid the foundation for three broad areas of science. First, they focused studies on the origins of cancer to the molecular level, with the subsequent discovery of genes mutated in cancer that now number in the thousands. Second, elucidation of the biochemical mechanisms by which Ras facilitates signal transduction established many of our fundamental concepts of how a normal cell orchestrates responses to extracellular cues. Third, Ras proteins are also founding members of a large superfamily of small GTPases that regulate all key cellular processes and established the versatile role of small GTP-binding proteins in biology. We highlight some of the key findings of the last 28 years.
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Affiliation(s)
- Adrienne D Cox
- Department of Radiation Oncology; Lineberger Comprehensive Cancer Center; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
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34
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Gentry LR, Martin TD, Reiner DJ, Der CJ. Ral small GTPase signaling and oncogenesis: More than just 15minutes of fame. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2976-2988. [PMID: 25219551 DOI: 10.1016/j.bbamcr.2014.09.004] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/03/2014] [Accepted: 09/04/2014] [Indexed: 01/26/2023]
Abstract
Since their discovery in 1986, Ral (Ras-like) GTPases have emerged as critical regulators of diverse cellular functions. Ral-selective guanine nucleotide exchange factors (RalGEFs) function as downstream effectors of the Ras oncoprotein, and the RalGEF-Ral signaling network comprises the third best characterized effector of Ras-dependent human oncogenesis. Because of this, Ral GTPases as well as their effectors are being explored as possible therapeutic targets in the treatment of RAS mutant cancer. The two Ral isoforms, RalA and RalB, interact with a variety of downstream effectors and have been found to play key and distinct roles in both normal and neoplastic cell physiology including regulation of vesicular trafficking, migration and invasion, tumor formation, metastasis, and gene expression. In this review we provide an overview of Ral biochemistry and biology, and we highlight recent discoveries.
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Affiliation(s)
- Leanna R Gentry
- University of North Carolina at Chapel Hill, Department of Pharmacology, Chapel Hill, NC, USA
| | | | - David J Reiner
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, USA
| | - Channing J Der
- University of North Carolina at Chapel Hill, Department of Pharmacology, Chapel Hill, NC, USA; University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Chapel Hill, NC, USA.
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35
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Oeckinghaus A, Postler TS, Rao P, Schmitt H, Schmitt V, Grinberg-Bleyer Y, Kühn LI, Gruber CW, Lienhard GE, Ghosh S. κB-Ras proteins regulate both NF-κB-dependent inflammation and Ral-dependent proliferation. Cell Rep 2014; 8:1793-1807. [PMID: 25220458 DOI: 10.1016/j.celrep.2014.08.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 06/19/2014] [Accepted: 08/06/2014] [Indexed: 02/01/2023] Open
Abstract
The transformation of cells generally involves multiple genetic lesions that undermine control of both cell death and proliferation. We now report that κB-Ras proteins act as regulators of NF-κB and Ral pathways, which control inflammation/cell death and proliferation, respectively. Cells lacking κB-Ras therefore not only show increased NF-κB activity, which results in increased expression of inflammatory mediators, but also exhibit elevated Ral activity, which leads to enhanced anchorage-independent proliferation (AIP). κB-Ras deficiency consequently leads to significantly increased tumor growth that can be dampened by inhibiting either Ral or NF-κB pathways, revealing the unique tumor-suppressive potential of κB-Ras proteins. Remarkably, numerous human tumors show reduced levels of κB-Ras, and increasing the level of κB-Ras in these tumor cells impairs their ability to undergo AIP, thereby implicating κB-Ras proteins in human disease.
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Affiliation(s)
- Andrea Oeckinghaus
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Thomas S Postler
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Ping Rao
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Heike Schmitt
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Verena Schmitt
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Yenkel Grinberg-Bleyer
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Lars I Kühn
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Gustav E Lienhard
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Sankar Ghosh
- Department of Microbiology and Immunology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
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Tecleab A, Zhang X, Sebti SM. Ral GTPase down-regulation stabilizes and reactivates p53 to inhibit malignant transformation. J Biol Chem 2014; 289:31296-309. [PMID: 25210032 DOI: 10.1074/jbc.m114.565796] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ral GTPases are critical effectors of Ras, yet the molecular mechanism by which they induce malignant transformation is not well understood. In this study, we found the expression of K-Ras, RalB, and sometimes RalA, but not AKT1/2 and c-Raf, to be required for maintaining low levels of p53 in human cancer cells that harbor mutant K-Ras and wild-type p53. Down-regulation of K-Ras, RalB, and sometimes RalA increases p53 protein levels and results in a p53-dependent up-regulation of the expression of p21(WAF). K-Ras, RalA, and RalB depletion increases p53 stability as demonstrated by ataxia telangiectasia-mutated kinase activation, increased Ser-15 phosphorylation, and a significant (up to 6-fold) increase in p53 half-life. Furthermore, depletion of K-Ras and RalB inhibits anchorage-independent growth and invasion and interferes with cell cycle progression in a p53-dependent manner. Depletion of RalA inhibits invasion in a p53-dependent manner. Thus, expression of K-Ras and RalB and possibly RalA proteins is critical for maintaining low levels of p53, and down-regulation of these GTPases reactivates p53 by significantly enhancing its stability, and this contributes to suppression of malignant transformation.
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Affiliation(s)
- Awet Tecleab
- From the Drug Discovery Department, H. Lee Moffitt Cancer Center and Research Institute and the Departments of Oncologic Sciences and Molecular Medicine, University of South Florida, Tampa, Florida 33612
| | - Xiaolei Zhang
- From the Drug Discovery Department, H. Lee Moffitt Cancer Center and Research Institute and
| | - Said M Sebti
- From the Drug Discovery Department, H. Lee Moffitt Cancer Center and Research Institute and the Departments of Oncologic Sciences and Molecular Medicine, University of South Florida, Tampa, Florida 33612
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Tang SC, Chen YC. Novel therapeutic targets for pancreatic cancer. World J Gastroenterol 2014; 20:10825-10844. [PMID: 25152585 PMCID: PMC4138462 DOI: 10.3748/wjg.v20.i31.10825] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/13/2014] [Accepted: 04/09/2014] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer has become the fourth leading cause of cancer death in the last two decades. Only 3%-15% of patients diagnosed with pancreatic cancer had 5 year survival rate. Drug resistance, high metastasis, poor prognosis and tumour relapse contributed to the malignancies and difficulties in treating pancreatic cancer. The current standard chemotherapy for pancreatic cancer is gemcitabine, however its efficacy is far from satisfactory, one of the reasons is due to the complex tumour microenvironment which decreases effective drug delivery to target cancer cell. Studies of the molecular pathology of pancreatic cancer have revealed that activation of KRAS, overexpression of cyclooxygenase-2, inactivation of p16INK4A and loss of p53 activities occurred in pancreatic cancer. Co-administration of gemcitabine and targeting the molecular pathological events happened in pancreatic cancer has brought an enhanced therapeutic effectiveness of gemcitabine. Therefore, studies looking for novel targets in hindering pancreatic tumour growth are emerging rapidly. In order to give a better understanding of the current findings and to seek the direction in future pancreatic cancer research; in this review we will focus on targets suppressing tumour metastatsis and progression, KRAS activated downstream effectors, the relationship of Notch signaling and Nodal/Activin signaling with pancreatic cancer cells, the current findings of non-coding RNAs in inhibiting pancreatic cancer cell proliferation, brief discussion in transcription remodeling by epigenetic modifiers (e.g., HDAC, BMI1, EZH2) and the plausible therapeutic applications of cancer stem cell and hyaluronan in tumour environment.
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38
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Kim EY, Kim A, Kim SK, Kim HJ, Chang J, Ahn CM, Lee JS, Shim HS, Chang YS. KRAS oncogene substitutions in Korean NSCLC patients: Clinical implication and relationship with pAKT and RalGTPases expression. Lung Cancer 2014; 85:299-305. [DOI: 10.1016/j.lungcan.2014.04.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 04/10/2014] [Accepted: 04/23/2014] [Indexed: 12/23/2022]
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39
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Personnic N, Lakisic G, Gouin E, Rousseau A, Gautreau A, Cossart P, Bierne H. A role for Ral GTPase-activating protein subunit β in mitotic regulation. FEBS J 2014; 281:2977-89. [PMID: 24814574 DOI: 10.1111/febs.12836] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 01/05/2023]
Abstract
Ral proteins are small GTPases that play critical roles in normal physiology and in oncogenesis. There is little information on the GTPase-activating proteins (GAPs) that downregulate their activity. Here, we provide evidence that the noncatalytic β subunit of RalGAPα1/2 β complexes is involved in mitotic control. RalGAPβ localizes to the Golgi and nucleus during interphase, and relocalizes to the mitotic spindle and cytokinetic intercellular bridge during mitosis. Depletion of RalGAPβ causes chromosome misalignment and decreases the amount of mitotic cyclin B1, disturbing the metaphase-to-anaphase transition. Overexpression of RalGAPβ interferes with cell division, leading to binucleation and multinucleation, and cell death. We propose that RalGAPβ plays an essential role in the sequential progression of mitosis by controlling the spatial and temporal activation of Ral GTPases in the spindle assembly checkpoint (SAC) and cytokinesis. Deregulation of RalGAPβ might cause genomic instability, leading to human carcinogenesis.
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Affiliation(s)
- Nicolas Personnic
- Institut Pasteur, Unité des interactions Bactéries cellules, Paris, France; Inserm, U604, Paris, France; INRA, USC2020, Paris, France
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Ezzeldin M, Borrego-Diaz E, Taha M, Esfandyari T, Wise AL, Peng W, Rouyanian A, Asvadi Kermani A, Soleimani M, Patrad E, Lialyte K, Wang K, Williamson S, Abdulkarim B, Olyaee M, Farassati F. RalA signaling pathway as a therapeutic target in hepatocellular carcinoma (HCC). Mol Oncol 2014; 8:1043-53. [PMID: 24785097 DOI: 10.1016/j.molonc.2014.03.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/12/2014] [Accepted: 03/24/2014] [Indexed: 12/23/2022] Open
Abstract
Ral (Ras like) leads an important proto-oncogenic signaling pathway down-stream of Ras. In this work, RalA was found to be significantly overactivated in hepatocellular carcinoma (HCC) cells and tissues as compared to non-malignant samples. Other elements of RalA pathway such as RalBP1 and RalGDS were also expressed at higher levels in malignant samples. Inhibition of RalA by gene-specific silencing caused a robust decrease in the viability and invasiveness of HCC cells. Additionally, the use of geranyl-geranyl transferase inhibitor (GGTI, an inhibitor of Ral activation) and Aurora kinase inhibitor II resulted in a significant decrease in the proliferation of HCC cells. Furthermore, RalA activation was found to be at a higher level of activation in HCC stem cells that express CD133. Transgenic mouse model for HCC (FXR-Knockout) also revealed an elevated level of RalA-GTP in the liver tumors as compared to background animals. Finally, subcutaneous mouse model for HCC confirmed effectiveness of inhibition of aurora kinase/RalA pathway in reducing the tumorigenesis of HCC cells in vivo. In conclusion, RalA overactivation is an important determinant of malignant phenotype in differentiated and stem cells of HCC and can be considered as a target for therapeutic intervention.
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Affiliation(s)
- Mohamad Ezzeldin
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Emma Borrego-Diaz
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Mohammad Taha
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Tuba Esfandyari
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Amanda L Wise
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Warner Peng
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Alex Rouyanian
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Atabak Asvadi Kermani
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Mina Soleimani
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Elham Patrad
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Kristina Lialyte
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Kun Wang
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Stephen Williamson
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Bashar Abdulkarim
- The University of Kansas Medical Center, Department of Surgery, Kansas City, KS, USA
| | - Mojtaba Olyaee
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA
| | - Faris Farassati
- The University of Kansas Medical School, Divisions of Gastroenterology, Hepatology and Motility and Hematology/Oncology, Molecular Medicine Laboratory, Kansas City, KS, USA.
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41
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Ebi H, Faber AC, Engelman JA, Yano S. Not just gRASping at flaws: finding vulnerabilities to develop novel therapies for treating KRAS mutant cancers. Cancer Sci 2014; 105:499-505. [PMID: 24612015 PMCID: PMC4317830 DOI: 10.1111/cas.12383] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/14/2014] [Accepted: 02/17/2014] [Indexed: 01/02/2023] Open
Abstract
Mutations in Kirsten rat-sarcoma (KRAS) are well appreciated to be major drivers of human cancers through dysregulation of multiple growth and survival pathways. Similar to many other non-kinase oncogenes and tumor suppressors, efforts to directly target KRAS pharmaceutically have not yet materialized. As a result, there is broad interest in an alternative approach to develop therapies that induce synthetic lethality in cancers with mutant KRAS, therefore exposing the particular vulnerabilities of these cancers. Fueling these efforts is our increased understanding into the biology driving KRAS mutant cancers, in particular the important pathways that mutant KRAS governs to promote survival. In this mini-review, we summarize the latest approaches to treat KRAS mutant cancers and the rationale behind them.
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Affiliation(s)
- Hiromichi Ebi
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
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42
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Stout MC, Asiimwe E, Birkenstamm JR, Kim SY, Campbell PM. Analyzing Ras-associated cell proliferation signaling. Methods Mol Biol 2014; 1170:393-409. [PMID: 24906326 DOI: 10.1007/978-1-4939-0888-2_21] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ras-dependent signaling is an important regulator of cell cycle progression, proliferation, senescence, and apoptosis. Several of the downstream effectors of Ras play dual roles in each of these processes. Under one set of conditions, they promote cell cycle progression and proliferation; yet, in a different paradigm, they drive cell cycle arrest and apoptosis. Furthermore, there is cross talk between certain downstream effectors of Ras including the PI3K-AKT and Raf-MEK-ERK pathways. Here we describe a series of experiments used to dissect the effect of different Ras-dependent signaling pathways on cell cycle progression, proliferation, senescence, and apoptosis. Furthermore, we highlight the importance of consistent growth conditions of cells in culture when studying Ras-dependent signaling as we show that the activation of downstream effectors of Ras changes with the confluency at which the cells are grown.
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Affiliation(s)
- Matthew C Stout
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, MS 488, Philadelphia, PA, 19102, USA
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Rajasekar K, Campbell L, Nietlispach D, Owen D, Mott H. The structure of the RLIP76 RhoGAP-Ral binding domain dyad: fixed position of the domains leads to dual engagement of small G proteins at the membrane. Structure 2013; 21:2131-42. [PMID: 24207123 PMCID: PMC3852207 DOI: 10.1016/j.str.2013.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 09/12/2013] [Accepted: 09/13/2013] [Indexed: 01/15/2023]
Abstract
RLIP76 is an effector for Ral small GTPases, which in turn lie downstream of the master regulator Ras. Evidence is growing that Ral and RLIP76 play a role in tumorigenesis, invasion, and metastasis. RLIP76 contains both a RhoGAP domain and a Ral binding domain (GBD) and is, therefore, a node between Ras and Rho family signaling. The structure of the RhoGAP-GBD dyad reveals that the RLIP76 RhoGAP domain adopts a canonical RhoGAP domain structure and that the linker between the two RLIP76 domains is structured, fixing the orientation of the two domains and allowing RLIP76 to interact with Rho-family GTPases and Ral simultaneously. However, the juxtaposed domains do not influence each other functionally, suggesting that the RLIP76-Ral interaction controls cellular localization and that the fixed orientation of the two domains orientates the RhoGAP domain with respect to the membrane, allowing it to be perfectly poised to engage its target G proteins.
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Affiliation(s)
- Karthik V. Rajasekar
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Louise J. Campbell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Darerca Owen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Helen R. Mott
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
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Fredericks J, Ren R. The role of RAS effectors in BCR/ABL induced chronic myelogenous leukemia. Front Med 2013; 7:452-61. [PMID: 24264166 DOI: 10.1007/s11684-013-0304-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/16/2013] [Indexed: 01/08/2023]
Abstract
BCR/ABL is the causative agent of chronic myelogenous leukemia (CML). Through structure/function analysis, several protein motifs have been determined to be important for the development of leukemogenesis. Tyrosine177 of BCR is a Grb2 binding site required for BCR/ABL-induced CML in mice. In the current study, we use a mouse bone marrow transduction/transplantation system to demonstrate that addition of oncogenic NRAS (NRASG12D) to a vector containing a BCR/ABL(Y177F) mutant "rescues" the CML phenotype rapidly and efficiently. To further narrow down the pathways downstream of RAS that are responsible for this rescue effect, we utilize well-characterized RAS effector loop mutants and determine that the RAL pathway is important for rapid induction of CML. Inhibition of this pathway by a dominant negative RAL is capable of delaying disease progression. Results from the present study support the notion of RAL inhibition as a potential therapy for BCR/ABL-induced CML.
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Affiliation(s)
- Jessica Fredericks
- State Key Laboratory for Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
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Abstract
Recognition that Ral guanine nucleotide exchange factors (RalGEFs) are direct Ras effectors and that Ral G-protein activation is a direct consequence of Ras activation has spurred focused efforts to establish the contribution of RalGEF/Ral signaling to oncogenic transformation. Here, we provide a broad-strokes overview of the mechanistic organization of the RalGEF/Ral signaling network, evaluate the evidence for participation of this network in tumorigenic regulatory milieus, consider targeting strategies, and discuss the challenges to and opportunities for clinical development of these targeting strategies.
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Affiliation(s)
- Jonathan M Cooper
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Brian O Bodemann
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Michael A White
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, USA.
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46
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Ral GTPases in tumorigenesis: emerging from the shadows. Exp Cell Res 2013; 319:2337-42. [PMID: 23830877 DOI: 10.1016/j.yexcr.2013.06.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/18/2013] [Accepted: 06/26/2013] [Indexed: 01/03/2023]
Abstract
Oncogenic Ras proteins rely on a series of key effector pathways to drive the physiological changes that lead to tumorigenic growth. Of these effector pathways, the RalGEF pathway, which activates the two Ras-related GTPases RalA and RalB, remains the most poorly understood. This review will focus on key developments in our understanding of Ral biology, and will speculate on how aberrant activation of the multiple diverse Ral effector proteins might collectively contribute to oncogenic transformation and other aspects of tumor progression.
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47
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van den Berg MCW, van Gogh IJA, Smits AMM, van Triest M, Dansen TB, Visscher M, Polderman PE, Vliem MJ, Rehmann H, Burgering BMT. The small GTPase RALA controls c-Jun N-terminal kinase-mediated FOXO activation by regulation of a JIP1 scaffold complex. J Biol Chem 2013; 288:21729-41. [PMID: 23770673 DOI: 10.1074/jbc.m113.463885] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FOXO (forkhead box O) transcription factors are tumor suppressors and increase the life spans of model organisms. Cellular stress, in particular oxidative stress caused by an increase in levels of reactive oxygen species (ROS), activates FOXOs through JNK-mediated phosphorylation. Importantly, JNK regulation of FOXO is evolutionarily conserved. Here we identified the pathway that mediates ROS-induced JNK-dependent FOXO regulation. Following increased ROS, RALA is activated by the exchange factor RLF (RalGDS-like factor), which is in complex with JIP1 (C-Jun-amino-terminal-interacting protein 1) and JNK. Active RALA consequently regulates assembly and activation of MLK3, MKK4, and JNK onto the JIP1 scaffold. Furthermore, regulation of FOXO by RALA and JIP1 is conserved in C. elegans, where both ral-1 and jip-1 depletion impairs heat shock-induced nuclear translocation of the FOXO orthologue DAF16.
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Affiliation(s)
- Maaike C W van den Berg
- Molecular Cancer Research, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands
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48
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Tazat K, Harsat M, Goldshmid-Shagal A, Ehrlich M, Henis YI. Dual effects of Ral-activated pathways on p27 localization and TGF-β signaling. Mol Biol Cell 2013; 24:1812-24. [PMID: 23576547 PMCID: PMC3667732 DOI: 10.1091/mbc.e13-01-0007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Constitutive activation or overactivation of Ras signaling pathways contributes to epithelial tumorigenesis in several ways, one of which is cytoplasmic mislocalization of the cyclin-dependent kinase inhibitor p27(Kip1) (p27). We previously showed that such an effect can be mediated by activation of the Ral-GEF pathway by oncogenic N-Ras. However, the mechanism(s) leading to p27 cytoplasmic accumulation downstream of activated Ral remained unknown. Here, we report a dual regulation of p27 cellular localization by Ral downstream pathways, based on opposing effects via the Ral effectors RalBP1 and phospholipase D1 (PLD1). Because RalA and RalB are equally effective in mislocalizing both murine and human p27, we focus on RalA and murine p27, which lacks the Thr-157 phosphorylation site of human p27. In experiments based on specific RalA and p27 mutants, complemented with short hairpin RNA-mediated knockdown of Ral downstream signaling components, we show that activation of RalBP1 induces cytoplasmic accumulation of p27 and that this event requires p27 Ser-10 phosphorylation by protein kinase B/Akt. Of note, activation of PLD1 counteracts this effect in a Ser-10-independent manner. The physiological relevance of the modulation of p27 localization by Ral is demonstrated by the ability of Ral-mediated activation of the RalBP1 pathway to abrogate transforming growth factor-β-mediated growth arrest in epithelial cells.
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Affiliation(s)
- Keren Tazat
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Martin TD, Der CJ. Differential involvement of RalA and RalB in colorectal cancer. Small GTPases 2013; 3:126-30. [PMID: 22790202 PMCID: PMC3408977 DOI: 10.4161/sgtp.19571] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutationally activated K-Ras can utilize a multitude of downstream effector proteins to promote oncogenesis. While the Raf and phosphoinositol 3-kinase effector pathways are the best-studied and validated, recent studies have established the critical importance of Ral guanine nucleotide exchange factor (RalGEF) activation of the RalA and RalB small GTPases in cancer biology. Due to recent evidence that the RalGEF-Ral pathway is necessary for the tumorigenic and metastatic potential of KRAS mutant pancreatic ductal adenocarcinoma (PDAC) tumor cells, we investigated whether or not Ral signaling was necessary for KRAS mutant colorectal cancer (CRC) tumor cell growth. As in PDAC, we found upregulated RalA and RalB activation in CRC tumor cell lines and tumors. Surprisingly we found antagonistic roles for RalA and RalB in the regulation of CRC tumor cell anchorage-independent growth. This observation contrasts with PDAC, where RalA but not RalB is necessary for PDAC tumor cell anchorage-independent growth. Our results emphasize cancer cell type differences in Ral function and hence the need for distinct Ral targeted therapeutic approaches in the treatment of CRC vs. PDAC.
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Affiliation(s)
- Timothy D Martin
- Deparment of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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50
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Leto D, Uhm M, Williams A, Chen XW, Saltiel AR. Negative regulation of the RalGAP complex by 14-3-3. J Biol Chem 2013; 288:9272-83. [PMID: 23386617 DOI: 10.1074/jbc.m112.426106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RGC1 and RGC2 comprise a functional RalGAP complex (RGC) that suppresses RalA activity. The PI3-kinase/Akt signaling pathway activates RalA through phosphorylation-mediated inhibition of the RGC. Here we identify a novel phosphorylation-dependent interaction between 14-3-3 and the RGC. 14-3-3 binds to the complex through an Akt-phosphorylated residue, threonine 715, on RGC2. Interaction with 14-3-3 does not alter in vitro activity of the GTPase-activating protein complex. However, blocking the interaction between 14-3-3 and RGC2 in cells increases suppression of RalA activity by the RGC, suggesting that 14-3-3 inhibits the complex through a non-catalytic mechanism. Together, these data show that 14-3-3 negatively regulates the RGC downstream of the PI3-kinase/Akt signaling pathway.
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Affiliation(s)
- Dara Leto
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
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