1
|
Sanidas I, Lawrence MS, Dyson NJ. Patterns in the tapestry of chromatin-bound RB. Trends Cell Biol 2024; 34:288-298. [PMID: 37648594 PMCID: PMC10899529 DOI: 10.1016/j.tcb.2023.07.012] [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: 05/01/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
The retinoblastoma protein (RB)-mediated regulation of E2F is a component of a highly conserved cell cycle machine. However, RB's tumor suppressor activity, like RB's requirement in animal development, is tissue-specific, context-specific, and sometimes appears uncoupled from cell proliferation. Detailed new information about RB's genomic distribution provides a new perspective on the complexity of RB function, suggesting that some of its functional specificity results from context-specific RB association with chromatin. Here we summarize recent evidence showing that RB targets different types of chromatin regulatory elements at different cell cycle stages. RB controls traditional RB/E2F targets prior to S-phase, but, when cells proliferate, RB redistributes to cell type-specific chromatin loci. We discuss the broad implications of the new data for RB research.
Collapse
Affiliation(s)
- Ioannis Sanidas
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA
| | - Michael S Lawrence
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA.
| |
Collapse
|
2
|
Olson BM, Chaudagar K, Bao R, Saha SS, Hong C, Li M, Rameshbabu S, Chen R, Thomas A, Patnaik A. BET Inhibition Sensitizes Immunologically Cold Rb-Deficient Prostate Cancer to Immune Checkpoint Blockade. Mol Cancer Ther 2023; 22:751-764. [PMID: 37014264 PMCID: PMC10239341 DOI: 10.1158/1535-7163.mct-22-0369] [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: 05/25/2022] [Revised: 01/09/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023]
Abstract
Non-T-cell-inflamed immunologically "cold" tumor microenvironments (TME) are associated with poor responsiveness to immune checkpoint blockade (ICB) and can be sculpted by tumor cell genomics. Here, we evaluated how retinoblastoma (Rb) tumor-suppressor loss-of-function (LOF), one of the most frequent alterations in human cancer and associated with lineage plasticity, poor prognosis, and therapeutic outcomes, alters the TME, and whether therapeutic strategies targeting the molecular consequences of Rb loss enhance ICB efficacy. We performed bioinformatics analysis to elucidate the impact of endogenous Rb LOF on the immune TME in human primary and metastatic tumors. Next, we used isogenic murine models of Rb-deficient prostate cancer for in vitro and in vivo mechanistic studies to examine how Rb loss and bromodomain and extraterminal (BET) domain inhibition (BETi) reprograms the immune landscape, and evaluated in vivo therapeutic efficacy of BETi, singly and in combination with ICB and androgen deprivation therapy. Rb loss was enriched in non-T-cell-inflamed tumors, and Rb-deficient murine tumors demonstrated decreased immune infiltration in vivo. The BETi JQ1 increased immune infiltration into the TME through enhanced tumor cell STING/NF-κB activation and type I IFN signaling within tumor cells, resulting in differential macrophage and T-cell-mediated tumor growth inhibition and sensitization of Rb-deficient prostate cancer to ICB. BETi can reprogram the immunologically cold Rb-deficient TME via STING/NF-κB/IFN signaling to sensitize Rb-deficient prostate cancer to ICB. These data provide the mechanistic rationale to test combinations of BETi and ICB in clinical trials of Rb-deficient prostate cancer.
Collapse
Affiliation(s)
- Brian M. Olson
- Department of Hematology and Medical Oncology; Emory University, Atlanta, GA
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
| | - Kiranj Chaudagar
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
| | - Riyue Bao
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
- Center for Research Informatics, University of Chicago, Chicago, IL
- Cancer Bioinformatics Services, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Sweta Sharma Saha
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
- Department of Pediatrics, University of Chicago, Chicago, IL; Translational and Clinical Research Institute, Newcastle University Centre for Cancer, Newcastle upon Tyne, United Kingdom
| | - Christina Hong
- Department of Hematology and Medical Oncology; Emory University, Atlanta, GA
| | - Marguerite Li
- Department of Hematology and Medical Oncology; Emory University, Atlanta, GA
| | - Srikrishnan Rameshbabu
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
| | - Raymond Chen
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
| | - Alison Thomas
- Department of Hematology and Medical Oncology; Emory University, Atlanta, GA
| | - Akash Patnaik
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL
| |
Collapse
|
3
|
Sanidas I, Lee H, Rumde PH, Boulay G, Morris R, Golczer G, Stanzione M, Hajizadeh S, Zhong J, Ryan MB, Corcoran RB, Drapkin BJ, Rivera MN, Dyson NJ, Lawrence MS. Chromatin-bound RB targets promoters, enhancers, and CTCF-bound loci and is redistributed by cell-cycle progression. Mol Cell 2022; 82:3333-3349.e9. [PMID: 35981542 PMCID: PMC9481721 DOI: 10.1016/j.molcel.2022.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/19/2022] [Accepted: 07/20/2022] [Indexed: 02/06/2023]
Abstract
The interaction of RB with chromatin is key to understanding its molecular functions. Here, for first time, we identify the full spectrum of chromatin-bound RB. Rather than exclusively binding promoters, as is often described, RB targets three fundamentally different types of loci (promoters, enhancers, and insulators), which are largely distinguishable by the mutually exclusive presence of E2F1, c-Jun, and CTCF. While E2F/DP facilitates RB association with promoters, AP-1 recruits RB to enhancers. Although phosphorylation in CDK sites is often portrayed as releasing RB from chromatin, we show that the cell cycle redistributes RB so that it enriches at promoters in G1 and at non-promoter sites in cycling cells. RB-bound promoters include the classic E2F-targets and are similar between lineages, but RB-bound enhancers associate with different categories of genes and vary between cell types. Thus, RB has a well-preserved role controlling E2F in G1, and it targets cell-type-specific enhancers and CTCF sites when cells enter S-phase.
Collapse
Affiliation(s)
- Ioannis Sanidas
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Hanjun Lee
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Purva H Rumde
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Gaylor Boulay
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Robert Morris
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Gabriel Golczer
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Marcelo Stanzione
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Soroush Hajizadeh
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Jun Zhong
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Meagan B Ryan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Ryan B Corcoran
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Benjamin J Drapkin
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
| | - Miguel N Rivera
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA.
| | - Michael S Lawrence
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA.
| |
Collapse
|
4
|
Dowlati A, Abbas A, Chan T, Henick B, Wang X, Doshi P, Fu P, Patel J, Kuo F, Chang H, Balli D. Immune Checkpoint Blockade Outcome in Small-Cell Lung Cancer and Its Relationship With Retinoblastoma Mutation Status and Function. JCO Precis Oncol 2022; 6:e2200257. [PMID: 36044718 PMCID: PMC9489185 DOI: 10.1200/po.22.00257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/06/2022] [Accepted: 07/15/2022] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Immune checkpoint blockade (ICB) in conjunction with chemotherapy is approved for the treatment of extensive-stage small-cell lung cancer (SCLC). Although specific genomic abnormalities such as KEAP1 and STK11 gene mutations are associated with resistance to ICB in non-SCLC, no genomic abnormality has been found in association with resistance to ICB in SCLC. MATERIALS AND METHODS We first analyzed a retrospective cohort of 42 patients with SCLC treated with single-agent ICB or ICB combination (data set A). We then validated our results in a large prospective clinical trial of 460 patients (CheckMate 032, data set B). DNA and RNA sequencing were performed. RESULTS In data set A, patients treated with ICB with RB1 wild-type (WT) had a median overall survival (OS) of 23.1 months (95% CI, 9 to 37.5), whereas the RB1 mutant OS was 5 months (95% CI, 2.5 to 26; P = .04). Differentially expressed gene analysis between RB1 mutant and RB1 WT samples indicated the enrichment of downregulated immune-related genes and an immune exclusion phenotype among RB1 mutant but not in the RB1 WT tumor samples. We then assessed results from 460 patients enrolled in CheckMate 032, a trial of nivolumab (NIVO) or NIVO + ipilimumab only in SCLC. In this large cohort, RB1 WT patients had significantly improved outcome with NIVO therapy compared with mutant patients (hazard ratio, 1.41; 95% CI, 1.02 to 2.01; P = .041). High RB1 loss-of-function (LOF) signature scores significantly associated with neuroendocrine subtypes (ASCL1 and NeuroD1). However, neuroendocrine subtypes did not associate with OS. Remarkably, patients with lower RB1 LOF scores had longer OS following treatment with NIVO. CONCLUSION SCLC patients with RB1 WT status or lower RB1 LOF signature scores by transcriptomics have better outcomes with ICB monotherapy.
Collapse
Affiliation(s)
- Afshin Dowlati
- University Hospitals Seidman Cancer Center and Case Western Reserve University, Cleveland, OH
| | - Ata Abbas
- University Hospitals Seidman Cancer Center and Case Western Reserve University, Cleveland, OH
| | - Timothy Chan
- Cleveland Clinic, Cleveland, OH
- Memorial Sloan Kettering Cancer Center, New York, NY
| | - Brian Henick
- Columbia University Medical Center, New York, NY
| | | | - Parul Doshi
- Bristol Myers Squibb, New York, NY
- Gilead Sciences, Foster City, CA
| | - Pingfu Fu
- University Hospitals Seidman Cancer Center and Case Western Reserve University, Cleveland, OH
| | | | - Fengshen Kuo
- Memorial Sloan Kettering Cancer Center, New York, NY
| | | | | |
Collapse
|
5
|
Lee C, Kim J. Genome maintenance in retinoblastoma: Implications for therapeutic vulnerabilities (Review). Oncol Lett 2022; 23:192. [PMID: 35527780 PMCID: PMC9073582 DOI: 10.3892/ol.2022.13312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/08/2022] [Indexed: 11/19/2022] Open
Abstract
Retinoblastoma (RB) is a pediatric ocular malignancy that is initiated mostly by biallelic inactivation of the RB transcriptional corepressor 1 (RB1) tumor suppressor gene in the developing retina. Unlike the prevailing prediction based on multiple studies involving RB1 gene disruption in experimental models, human RB tumors have been demonstrated to possess a relatively stable genome, characterized by a low mutation rate and a few recurrent chromosomal alterations related to somatic copy number changes. This suggests that RB may harbor heightened genome maintenance mechanisms to counteract or compensate for the risk of massive genome instability, which can potentially be driven by the early RB1 loss as a tumor-initiating event. Although the genome maintenance mechanisms might have been evolved to promote RB cell survival by preventing lethal genomic defects, emerging evidence suggests that the dependency of RB cells on these mechanisms also exposes their unique vulnerability to chemotherapy, particularly when the genome maintenance machineries are tumor cell-specific. This review summarizes the genome maintenance mechanisms identified in RB, including findings on the roles of chromatin regulators in DNA damage response/repair and protein factors involved in maintaining chromosome stability and promoting survival in RB. In addition, advantages and challenges for exploiting these therapeutic vulnerabilities in RB are discussed.
Collapse
Affiliation(s)
- Chunsik Lee
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Jong Kim
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| |
Collapse
|
6
|
Krishnan B, Yasuhara T, Rumde P, Stanzione M, Lu C, Lee H, Lawrence MS, Zou L, Nieman LT, Sanidas I, Dyson NJ. Active RB causes visible changes in nuclear organization. J Cell Biol 2022; 221:212957. [PMID: 35019938 PMCID: PMC8759594 DOI: 10.1083/jcb.202102144] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 10/21/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022] Open
Abstract
RB restricts G1/S progression by inhibiting E2F. Here, we show that sustained expression of active RB, and prolonged G1 arrest, causes visible changes in chromosome architecture that are not directly associated with E2F inhibition. Using FISH probes against two euchromatin RB-associated regions, two heterochromatin domains that lack RB-bound loci, and two whole-chromosome probes, we found that constitutively active RB (ΔCDK-RB) promoted a more diffuse, dispersed, and scattered chromatin organization. These changes were RB dependent, were driven by specific isoforms of monophosphorylated RB, and required known RB-associated activities. ΔCDK-RB altered physical interactions between RB-bound genomic loci, but the RB-induced changes in chromosome architecture were unaffected by dominant-negative DP1. The RB-induced changes appeared to be widespread and influenced chromosome localization within nuclei. Gene expression profiles revealed that the dispersion phenotype was associated with an increased autophagy response. We infer that, after cell cycle arrest, RB acts through noncanonical mechanisms to significantly change nuclear organization, and this reorganization correlates with transitions in cellular state.
Collapse
Affiliation(s)
- Badri Krishnan
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Takaaki Yasuhara
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Purva Rumde
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Marcello Stanzione
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Chenyue Lu
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Hanjun Lee
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Michael S Lawrence
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Linda T Nieman
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Ioannis Sanidas
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA
| |
Collapse
|
7
|
Janostiak R, Torres-Sanchez A, Posas F, de Nadal E. Understanding Retinoblastoma Post-Translational Regulation for the Design of Targeted Cancer Therapies. Cancers (Basel) 2022; 14:cancers14051265. [PMID: 35267571 PMCID: PMC8909233 DOI: 10.3390/cancers14051265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 01/05/2023] Open
Abstract
Simple Summary Rb1 is a regulator of cell cycle progression and genomic stability. This review focuses on post-translational modifications, their effect on Rb1 interactors, and their role in intracellular signaling in the context of cancer development. Finally, we highlight potential approaches to harness these post-translational modifications to design novel effective anticancer therapies. Abstract The retinoblastoma protein (Rb1) is a prototypical tumor suppressor protein whose role was described more than 40 years ago. Together with p107 (also known as RBL1) and p130 (also known as RBL2), the Rb1 belongs to a family of structurally and functionally similar proteins that inhibits cell cycle progression. Given the central role of Rb1 in regulating proliferation, its expression or function is altered in most types of cancer. One of the mechanisms underlying Rb-mediated cell cycle inhibition is the binding and repression of E2F transcription factors, and these processes are dependent on Rb1 phosphorylation status. However, recent work shows that Rb1 is a convergent point of many pathways and thus the regulation of its function through post-translational modifications is more complex than initially expected. Moreover, depending on the context, downstream signaling can be both E2F-dependent and -independent. This review seeks to summarize the most recent research on Rb1 function and regulation and discuss potential avenues for the design of novel cancer therapies.
Collapse
Affiliation(s)
- Radoslav Janostiak
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (R.J.); (A.T.-S.)
- Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Ariadna Torres-Sanchez
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (R.J.); (A.T.-S.)
- Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Francesc Posas
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (R.J.); (A.T.-S.)
- Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
- Correspondence: (F.P.); (E.d.N.); Tel.: +34-93-403-4810 (F.P.); +34-93-403-9895 (E.d.N.)
| | - Eulàlia de Nadal
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (R.J.); (A.T.-S.)
- Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
- Correspondence: (F.P.); (E.d.N.); Tel.: +34-93-403-4810 (F.P.); +34-93-403-9895 (E.d.N.)
| |
Collapse
|
8
|
Kinesin Family Member C1 (KIFC1/HSET): A Potential Actionable Biomarker of Early Stage Breast Tumorigenesis and Progression of High-Risk Lesions. J Pers Med 2021; 11:jpm11121361. [PMID: 34945833 PMCID: PMC8708236 DOI: 10.3390/jpm11121361] [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: 11/11/2021] [Revised: 11/29/2021] [Accepted: 12/08/2021] [Indexed: 12/14/2022] Open
Abstract
The enigma of why some premalignant or pre-invasive breast lesions transform and progress while others do not remains poorly understood. Currently, no radiologic or molecular biomarkers exist in the clinic that can successfully risk-stratify high-risk lesions for malignant transformation or tumor progression as well as serve as a minimally cytotoxic actionable target for at-risk subpopulations. Breast carcinogenesis involves a series of key molecular deregulatory events that prompt normal cells to bypass tumor-suppressive senescence barriers. Kinesin family member C1 (KIFC1/HSET), which confers survival of cancer cells burdened with extra centrosomes, has been observed in premalignant and pre-invasive lesions, and its expression has been shown to correlate with increasing neoplastic progression. Additionally, KIFC1 has been associated with aggressive breast tumor molecular subtypes, such as basal-like and triple-negative breast cancers. However, the role of KIFC1 in malignant transformation and its potential as a predictive biomarker of neoplastic progression remain elusive. Herein, we review compelling evidence suggesting the involvement of KIFC1 in enabling pre-neoplastic cells to bypass senescence barriers necessary to become immortalized and malignant. We also discuss evidence inferring that KIFC1 levels may be higher in premalignant lesions with a greater inclination to transform and acquire aggressive tumor intrinsic subtypes. Collectively, this evidence provides a strong impetus for further investigation into KIFC1 as a potential risk-stratifying biomarker and minimally cytotoxic actionable target for high-risk patient subpopulations.
Collapse
|
9
|
Hydroxyurea and Caffeine Impact pRb-like Protein-Dependent Chromatin Architecture Profiles in Interphase Cells of Vicia faba. Int J Mol Sci 2021; 22:ijms22094572. [PMID: 33925461 PMCID: PMC8123844 DOI: 10.3390/ijms22094572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/06/2021] [Accepted: 04/23/2021] [Indexed: 01/04/2023] Open
Abstract
The survival of cells depends on their ability to replicate correctly genetic material. Cells exposed to replication stress can experience a number of problems that may lead to deregulated proliferation, the development of cancer, and/or programmed cell death. In this article, we have induced prolonged replication arrest via hydroxyurea (HU) treatment and also premature chromosome condensation (PCC) by co-treatment with HU and caffeine (CF) in the root meristem cells of Vicia faba. We have analyzed the changes in the activities of retinoblastoma-like protein (RbS807/811ph). Results obtained from the immunocytochemical detection of RbS807/811ph allowed us to distinguish five unique activity profiles of pRb. We have also performed detailed 3D modeling using Blender 2.9.1., based on the original data and some final conclusions. 3D models helped us to visualize better the events occurring within the nuclei and acted as a high-resolution aid for presenting the results. We have found that, despite the decrease in pRb activity, its activity profiles were mostly intact and clearly recognizable, with some local alterations that may correspond to the increased demand in transcriptional activity. Our findings suggest that Vicia faba’s ability to withstand harsh environments may come from its well-developed and highly effective response to replication stress.
Collapse
|
10
|
Zluhan-Martínez E, Pérez-Koldenkova V, Ponce-Castañeda MV, Sánchez MDLP, García-Ponce B, Miguel-Hernández S, Álvarez-Buylla ER, Garay-Arroyo A. Beyond What Your Retina Can See: Similarities of Retinoblastoma Function between Plants and Animals, from Developmental Processes to Epigenetic Regulation. Int J Mol Sci 2020; 21:E4925. [PMID: 32664691 PMCID: PMC7404004 DOI: 10.3390/ijms21144925] [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: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
The Retinoblastoma protein (pRb) is a key cell cycle regulator conserved in a wide variety of organisms. Experimental analysis of pRb's functions in animals and plants has revealed that this protein participates in cell proliferation and differentiation processes. In addition, pRb in animals and its orthologs in plants (RBR), are part of highly conserved protein complexes which suggest the possibility that analogies exist not only between functions carried out by pRb orthologs themselves, but also in the structure and roles of the protein networks where these proteins are involved. Here, we present examples of pRb/RBR participation in cell cycle control, cell differentiation, and in the regulation of epigenetic changes and chromatin remodeling machinery, highlighting the similarities that exist between the composition of such networks in plants and animals.
Collapse
Affiliation(s)
- Estephania Zluhan-Martínez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
- Posgrado en Ciencias Biomédicas, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán 04510, Mexico
| | - Vadim Pérez-Koldenkova
- Laboratorio Nacional de Microscopía Avanzada, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Av. Cuauhtémoc, 330. Col. Doctores, Alc. Cuauhtémoc 06720, Mexico;
| | - Martha Verónica Ponce-Castañeda
- Unidad de Investigación Médica en Enfermedades Infecciosas, Centro Médico Nacional SXXI, Instituto Mexicano del Seguro Social, Mexico City 06720, Mexico;
| | - María de la Paz Sánchez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Sergio Miguel-Hernández
- Laboratorio de Citopatología Ambiental, Departamento de Morfología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Campus Zacatenco, Calle Wilfrido Massieu Esquina Cda, Manuel Stampa 07738, Mexico;
| | - Elena R. Álvarez-Buylla
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| |
Collapse
|
11
|
Okonska A, Bühler S, Rao V, Ronner M, Blijlevens M, van der Meulen-Muileman IH, de Menezes RX, Wipplinger M, Oehl K, Smit EF, Weder W, Stahel RA, Penengo L, van Beusechem VW, Felley-Bosco E. Functional Genomic Screen in Mesothelioma Reveals that Loss of Function of BRCA1-Associated Protein 1 Induces Chemoresistance to Ribonucleotide Reductase Inhibition. Mol Cancer Ther 2019; 19:552-563. [PMID: 31619462 DOI: 10.1158/1535-7163.mct-19-0356] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 09/06/2019] [Accepted: 10/10/2019] [Indexed: 11/16/2022]
Abstract
Loss of function of BRCA1-associated protein 1 (BAP1) is observed in about 50% of malignant pleural mesothelioma (MPM) cases. The aim of this study was to investigate whether this aspect could be exploited for targeted therapy. A genetically engineered model was established expressing either functional or nonfunctional BAP1, and whole-genome siRNA synthetic lethality screens were performed assessing differentially impaired survival between the two cell lines. The whole-genome siRNA screen unexpectedly revealed 11 hits (FDR < 0.05) that were more cytotoxic to BAP1-proficient cells. Two actionable targets, ribonucleotide reductase (RNR) catalytic subunit M1 (RRM1) and RNR regulatory subunit M2 (RRM2), were validated. In line with the screen results, primary mesothelioma (BAP1 +/-) overexpressing BAP1 C91A (catalytically dead mutant) was more resistant to RNR inhibition, while BAP1 knockdown in the BAP1-proficient cell lines rescued the cells from their vulnerability to RNR depletion. Gemcitabine and hydroxyurea were more cytotoxic in BAP1-proficient cell line-derived spheroids compared with BAP1 deficient. Upregulation of RRM2 upon gemcitabine and hydroxyurea treatment was more profound in BAP1 mut/del cell lines. Increased lethality mediated by RNR inhibition was observed in NCI-H2452 cells reconstituted with BAP1-WT but not with BAP1 C91A. Upregulation of RRM2 in NCI-H2452-BAP1 WT spheroids was modest compared with control or C91A mutant. Together, we found that BAP1 is involved in the regulation of RNR levels during replication stress. Our observations reveal a potential clinical application where BAP1 status could serve as predictive or stratification biomarker for RNR inhibition-based therapy in MPM.
Collapse
Affiliation(s)
- Agata Okonska
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland
| | - Saskja Bühler
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland
| | - Vasundhara Rao
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland
| | - Manuel Ronner
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland
| | - Maxime Blijlevens
- Amsterdam UMC, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | | | - Renee X de Menezes
- Amsterdam UMC, Vrije Universiteit Amsterdam, Epidemiology and Biostatistics, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Martin Wipplinger
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland
| | - Kathrin Oehl
- Institute of Pathology and Molecular Pathology, University Hospital Zürich, Zürich, Switzerland
| | - Egbert F Smit
- Department of Thoracic Surgery, NKI, Amsterdam, the Netherlands
| | - Walter Weder
- Department of Thoracic Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Rolf A Stahel
- Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, 8091 Zürich, Switzerland
| | - Lorenza Penengo
- Institute of Molecular Cancer Research, University of Zürich, Zürich, Switzerland
| | - Victor W van Beusechem
- Amsterdam UMC, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, the Netherlands
| | - Emanuela Felley-Bosco
- Laboratory of Molecular Oncology, Lungen- und Thoraxonkologie Zentrum, University Hospital Zürich, Zürich, Switzerland.
| |
Collapse
|
12
|
mSphere of Influence: Stromal Regulation of Epithelium Containing Viral Oncogenes. mSphere 2019; 4:4/4/e00467-19. [PMID: 31315968 PMCID: PMC6637048 DOI: 10.1128/msphere.00467-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Jason Bodily works in the field of tumor virology. In this mSphere of Influence article, he reflects on how “Inactivation of Rb in stromal fibroblasts promotes epithelial cell invasion” by Adam Pickard et al. (EMBO J 31:3092–3103, 2012, https://doi.org/10.1038/emboj.2012.153) has impacted his work by making him think about the role of stromal cells in human papillomavirus infections. Jason Bodily works in the field of tumor virology. In this mSphere of Influence article, he reflects on how “Inactivation of Rb in stromal fibroblasts promotes epithelial cell invasion” by Adam Pickard et al. (EMBO J 31:3092–3103, 2012, https://doi.org/10.1038/emboj.2012.153) has impacted his work by making him think about the role of stromal cells in human papillomavirus infections.
Collapse
|
13
|
Topacio BR, Zatulovskiy E, Cristea S, Xie S, Tambo CS, Rubin SM, Sage J, Kõivomägi M, Skotheim JM. Cyclin D-Cdk4,6 Drives Cell-Cycle Progression via the Retinoblastoma Protein's C-Terminal Helix. Mol Cell 2019; 74:758-770.e4. [PMID: 30982746 PMCID: PMC6800134 DOI: 10.1016/j.molcel.2019.03.020] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/01/2019] [Accepted: 03/19/2019] [Indexed: 01/10/2023]
Abstract
The cyclin-dependent kinases Cdk4 and Cdk6 form complexes with D-type cyclins to drive cell proliferation. A well-known target of cyclin D-Cdk4,6 is the retinoblastoma protein Rb, which inhibits cell-cycle progression until its inactivation by phosphorylation. However, the role of Rb phosphorylation by cyclin D-Cdk4,6 in cell-cycle progression is unclear because Rb can be phosphorylated by other cyclin-Cdks, and cyclin D-Cdk4,6 has other targets involved in cell division. Here, we show that cyclin D-Cdk4,6 docks one side of an alpha-helix in the Rb C terminus, which is not recognized by cyclins E, A, and B. This helix-based docking mechanism is shared by the p107 and p130 Rb-family members across metazoans. Mutation of the Rb C-terminal helix prevents its phosphorylation, promotes G1 arrest, and enhances Rb's tumor suppressive function. Our work conclusively demonstrates that the cyclin D-Rb interaction drives cell division and expands the diversity of known cyclin-based protein docking mechanisms.
Collapse
Affiliation(s)
| | | | - Sandra Cristea
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shicong Xie
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Carrie S Tambo
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Julien Sage
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mardo Kõivomägi
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
14
|
Knudsen ES, Pruitt SC, Hershberger PA, Witkiewicz AK, Goodrich DW. Cell Cycle and Beyond: Exploiting New RB1 Controlled Mechanisms for Cancer Therapy. Trends Cancer 2019; 5:308-324. [PMID: 31174843 DOI: 10.1016/j.trecan.2019.03.005] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 12/14/2022]
Abstract
Recent studies highlight the importance of the RB1 tumor suppressor as a target for cancer therapy. Canonically, RB1 regulates cell cycle progression and represents the downstream target for cyclin-dependent kinase (CDK) 4/6 inhibitors that are in clinical use. However, newly discovered features of the RB1 pathway suggest new therapeutic strategies to counter resistance and improve precision medicine. These therapeutic strategies include deepening cell cycle exit with CDK4/6 inhibitor combinations, selectively targeting tumors that have lost RB1, and expanding therapeutic index by mitigating therapy-associated adverse effects. In addition, RB1 impacts immunological features of tumors and the microenvironment that can enhance sensitivity to immunotherapy. Lastly, RB1 specifies epigenetically determined cell lineage states that are disrupted during therapy resistance and could be re-installed through the direct use of epigenetic therapies. Thus, new opportunities are emerging to improve cancer therapy by exploiting the RB1 pathway.
Collapse
Affiliation(s)
- Erik S Knudsen
- Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Center for Personalized Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA.
| | - Steven C Pruitt
- Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Pamela A Hershberger
- Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA; Department of Oral Oncology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - Agnieszka K Witkiewicz
- Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Center for Personalized Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA; Department of Pathology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - David W Goodrich
- Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA; Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| |
Collapse
|
15
|
Bandilovska I, Keam SP, Gamell C, Machicado C, Haupt S, Haupt Y. E6AP goes viral: the role of E6AP in viral- and non-viral-related cancers. Carcinogenesis 2019; 40:707-714. [DOI: 10.1093/carcin/bgz072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/12/2019] [Accepted: 04/08/2019] [Indexed: 02/07/2023] Open
Abstract
Abstract
Since its discovery, the E3 ubiquitin ligase E6-associated protein (E6AP) has been studied extensively in two pathological contexts: infection by the human papillomavirus (HPV), and the neurodevelopmental disorder, Angelman syndrome. Vital biological links between E6AP and other viruses, namely hepatitis C virus and encephalomyocarditis virus, have been recently uncovered. Critically, oncogenic E6AP activities have been demonstrated to contribute to cancers of both viral and non-viral origins. HPV-associated cancers serve as the primary example of E6AP involvement in cancers driven by viruses. Studies over the past few years have exposed a role for E6AP in non-viral-related cancers. This has been demonstrated in B-cell lymphoma and prostate cancers, where oncogenic E6AP functions drive these cancers by acting on key tumour suppressors. In this review we discuss the role of E6AP in viral infection, viral propagation and viral-related cancer. We discuss processes affected by oncogenic E6AP, which promote cancers of viral and non-viral aetiology. Overall, recent findings support the role of oncogenic E6AP in disrupting key cellular processes, including tumour suppression and the immune response. E6AP is consequently emerging as an attractive therapeutic target for a number of specific cancers.
Collapse
Affiliation(s)
- Ivona Bandilovska
- Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Simon P Keam
- Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Cristina Gamell
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Claudia Machicado
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Zaragoza, Spain
| | - Sue Haupt
- Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Ygal Haupt
- Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
- Department of Clinical Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
16
|
Morgan S, Slodkowska E, Parra-Herran C, Mirkovic J. PD-L1, RB1 and mismatch repair protein immunohistochemical expression in neuroendocrine carcinoma, small cell type, of the uterine cervix. Histopathology 2019; 74:997-1004. [PMID: 30667073 DOI: 10.1111/his.13825] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/18/2019] [Indexed: 01/02/2023]
Abstract
AIMS Neuroendocrine carcinoma, small cell type, of the uterine cervix (SmCC-Cx) is a rare human papilloma virus (HPV) related tumour with limited therapeutic options. Merkel cell carcinoma, another virus-associated neuroendocrine malignancy, has significant programmed death ligand 1 (PD-L1) expression rates. PD-L1 expression has been reported in other malignancies of the cervix. We aimed to determine the prevalence of PD-L1 in the context of mismatch repair protein (MMR) and RB1 expression status in SmCC-Cx. METHODS AND RESULTS Ten cases of SmCC-Cx were tested by immunohistochemistry for expression of PD-L1, MLH1, MSH2, MSH6, PMS2, RB1, CD3, CD20 and for HPV by in-situ hybridisation (ISH). PD-L1 expression was scored quantitatively (H-score) in tumour cells and lymphocytes (tumoral/peritumoral). PD-L1 positivity was seen in seven cases, focal in most (H-score range 3-140). Three of nine cases showed MMR deficiency. PD-L1 expression levels correlated with MMR expression status: all three MLH1/PMS2-deficient cases had a ≥5% PD-L1 staining and an H-score ≥10 (P = 0.01). RB1 was lost in four of nine cases, all PD-L1 positive, but this correlation was not statistically significant. Seven of nine tumours were positive for HPV-ISH; two of these had MLH1/PMS2 loss. Of the two HPV-ISH negative tumours, one had MLS1/PMS2 loss. CONCLUSIONS PD-L1 expression, predominantly focal, is seen in 70% of SmCC-Cx, while loss of MMR expression is seen in 33% of SmCC-Cx in our cohort. PD-L1 expression in more than 10% of tumour cells is seen in a subset of tumours in association with loss of MMR expression. These patients may be amenable to immune checkpoint inhibitor therapy as a promising alternative for this aggressive disease.
Collapse
Affiliation(s)
- Sarah Morgan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Elzbieta Slodkowska
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Carlos Parra-Herran
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Jelena Mirkovic
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| |
Collapse
|
17
|
Scott SC, Lee SS, Abraham J. Mechanisms of therapeutic CDK4/6 inhibition in breast cancer. Semin Oncol 2019; 44:385-394. [PMID: 29935900 DOI: 10.1053/j.seminoncol.2018.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 01/21/2018] [Indexed: 12/29/2022]
Abstract
Cyclin dependent kinase (CDK) 4/6 inhibitors have advanced the treatment of metastatic breast cancer by targeting the cell cycle machinery, interrupting intracellular and mitogenic hormone signals that stimulate proliferation of malignant cells. Preclinical evidence demonstrated that derangements of cyclin D1, CDK4/6, and retinoblastoma expression are common in breast cancer, and suggested a therapeutic benefit from interrupting this axis required for cell cycle progression. Studies of cell lines and animal models of breast cancer have demonstrated the complex interplay between the cell cycle and estrogen receptor and human epidermal growth receptor 2 signaling, which informs our understanding of synergistic use of CDK4/6 inhibitors with endocrine therapy, as well as mechanisms of resistance to endocrine therapy. Interestingly, estrogen receptor activity leads to upregulation of cyclin D1 expression, but the estrogen receptor is also in turn activated by cyclin D1, independent of estrogen binding. Early CDK inhibitors were nonspecific and limited by systemic toxicities, while the current generation of CDK4/6 inhibitors have shown promise in the treatment of hormone receptor-positive breast cancer. Preclinical investigations of the three CDK4/6 inhibitors approved by the US Food and Drug Administration (palbociclib, ribociclib, and abemaciclib) lend further insight into their mechanism of action, which will hopefully inform the future use and refinement of these therapies. Finally, we summarize evidence for additional novel CDK4/6 inhibitors currently in development.
Collapse
Affiliation(s)
| | - Sarah S Lee
- Cleveland Clinic Taussig Cancer Institute, Cleveland, OH
| | - Jame Abraham
- Cleveland Clinic Taussig Cancer Institute, Cleveland, OH.
| |
Collapse
|
18
|
Sanidas I, Morris R, Fella KA, Rumde PH, Boukhali M, Tai EC, Ting DT, Lawrence MS, Haas W, Dyson NJ. A Code of Mono-phosphorylation Modulates the Function of RB. Mol Cell 2019; 73:985-1000.e6. [PMID: 30711375 DOI: 10.1016/j.molcel.2019.01.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/26/2018] [Accepted: 01/02/2019] [Indexed: 12/21/2022]
Abstract
Hyper-phosphorylation of RB controls its interaction with E2F and inhibits its tumor suppressor properties. However, during G1 active RB can be mono-phosphorylated on any one of 14 CDK phosphorylation sites. Here, we used quantitative proteomics to profile protein complexes formed by each mono-phosphorylated RB isoform (mP-RB) and identified the associated transcriptional outputs. The results show that the 14 sites of mono-phosphorylation co-ordinate RB's interactions and confer functional specificity. All 14 mP-RBs interact with E2F/DP proteins, but they provide different shades of E2F regulation. RB mono-phosphorylation at S811, for example, alters RB transcriptional activity by promoting its association with NuRD complexes. The greatest functional differences between mP-RBs are evident beyond the cell cycle machinery. RB mono-phosphorylation at S811 or T826 stimulates the expression of oxidative phosphorylation genes, increasing cellular oxygen consumption. These results indicate that RB activation signals are integrated in a phosphorylation code that determines the diversity of RB activity.
Collapse
Affiliation(s)
- Ioannis Sanidas
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Robert Morris
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Katerina A Fella
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Purva H Rumde
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Myriam Boukhali
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Eric C Tai
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - David T Ting
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Michael S Lawrence
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA; Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, MA 02142, USA
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Building 149 13th Street, Charlestown, MA 02129, USA.
| |
Collapse
|
19
|
The Role of RB in Prostate Cancer Progression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1210:301-318. [PMID: 31900914 DOI: 10.1007/978-3-030-32656-2_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The RB tumor suppressor is one of the most commonly deleted/mutated genes in human cancers. In prostate cancer specifically, mutation of RB is most frequently observed in aggressive, metastatic disease. As one of the earliest tumor suppressors to be identified, the molecular functions of RB that are lost in tumor development have been studied for decades. Earlier work focused on the canonical RB pathway connecting mitogenic signaling to the cell cycle via Cyclin/CDK inactivation of RB, thereby releasing the E2F transcription factors. More in-depth analysis revealed that RB-E2F complexes regulate cellular processes beyond proliferation. Most recently, "non-canonical" roles for RB function have been expanded beyond its E2F interactions, which may play a particular role in advanced prostate cancer. For example, in mouse models of prostate cancer, loss of RB has been shown to induce lineage plasticity, which enables resistance to androgen deprivation therapy. This increased understanding of the potential downstream functions of RB in prostate cancer may lead the way to identifying therapeutic vulnerabilities in cells following RB loss.
Collapse
|
20
|
Reinhart D, Damjanovic L, Castan A, Ernst W, Kunert R. Differential gene expression of a feed-spiked super-producing CHO cell line. J Biotechnol 2018; 285:23-37. [PMID: 30157452 DOI: 10.1016/j.jbiotec.2018.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/15/2018] [Accepted: 08/25/2018] [Indexed: 01/09/2023]
Abstract
Feed supplements are concentrated cell culture media that contain a variety of nutrients, which can be added during a bioprocess. During fed-batch cultivation, feed media are typically added to a growing cell culture to maximize cell and product concentrations. In this study, only a single shot of feed medium was added on day 0 to a basal cell culture medium and compared to non-supplemented basal medium (feed-spiked at day 0 versus control experiments) by cultivation of a recombinant mAb expressing CHO cell line in batch mode under controlled conditions in a bioreactor. Since the feed-spike at day 0 was based on existing medium components without introducing additional supplements, a desirable process with decreased complexity was generated. Unlike cells in basal medium, feed-spiked cultures reached almost 2× higher peak cell concentrations (10 × 106 c/mL vs. 18 × 106 c/mL) and 3× higher antibody concentrations (0.8 g/L vs. 2.4 g/L). Batch process time and the integral over the viable cell count were similar for both process types. Constantly high cell-specific production rates in feed-spiked cultures (70 pg/cell/day) compared to continuously declining rates in basal medium (from 70 to 10 pg/cell/day) were responsible for an overall 70% higher cell-specific production rate and the higher product concentrations. To associate gene expression patterns to different process proceedings, transcriptome analysis was performed using microarrays. Several transcripts that are involved with glutamine de novo synthesis and citric acid cycle were significantly upregulated on several days in feed-spiked cultures. The top identified gene ontology (GO) terms related well to cell cycle and primary metabolism, cellular division as well as nucleobase formation or regulation, which indicated a more active proliferative state for feed-spiked cultures. KEGG biochemical pathway analysis and Gene set enrichment analysis (GSEA) further confirmed these findings from a complementary perspective. Moreover, several interesting gene targets, which have not yet been associated with recombinant protein expression, were identified that related to a higher proliferative state, growth, protein synthesis, cell-size control, metabolism, cell survival as well as genes that are associated with the control of the mammalian target of rapamycin (mTOR) in feed-spiked cultures. Analysis of critical product quality attributes (i.e. glycosylation, charge variants and size distribution) showed that feed-spiking did not change antibody quality.
Collapse
Affiliation(s)
- David Reinhart
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
| | - Lukas Damjanovic
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
| | - Andreas Castan
- GE Healthcare Life Sciences AB, Björkgatan 30, 75184, Uppsala, Sweden.
| | - Wolfgang Ernst
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
| | - Renate Kunert
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
| |
Collapse
|
21
|
Analysis of Polymorphisms in the Mediator Complex Subunit 13-like (Med13L) Gene in the Context of Immune Function and Development of Experimental Arthritis. Arch Immunol Ther Exp (Warsz) 2018; 66:365-377. [PMID: 29951696 PMCID: PMC6154033 DOI: 10.1007/s00005-018-0516-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/15/2018] [Indexed: 12/21/2022]
Abstract
The Mediator complex subunit 13-like (MED13L) protein is part of the multi-protein mediator complex and plays an important role in gene transcription. Polymorphisms in the MED13L gene have been linked to congenital heart anomalies and intellectual disabilities. Despite recent evidence of indirect links of MED13L to cytokine release and inflammation, impact of genetic variations in MED13L on immune cells remains unexplored. The B10.RIII and RIIIS/J mouse strains vary in susceptibility to induced experimental autoimmune disease models. From sequencing data of the two mouse strains, we identified six polymorphisms in the coding regions of Med13L. Using congenic mice, we studied the effect of these polymorphisms on immune cell development and function along with susceptibility to collagen-induced arthritis, an animal model for rheumatoid arthritis. Combining in vivo disease data, in vitro functional data, and computational analysis of the reported non-synonymous polymorphisms, we report that genetic polymorphisms in Med13L do not affect the immune phenotype in these mice and are predicted to be non-disease associated.
Collapse
|
22
|
Witkiewicz AK, Chung S, Brough R, Vail P, Franco J, Lord CJ, Knudsen ES. Targeting the Vulnerability of RB Tumor Suppressor Loss in Triple-Negative Breast Cancer. Cell Rep 2018; 22:1185-1199. [PMID: 29386107 PMCID: PMC5967622 DOI: 10.1016/j.celrep.2018.01.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/14/2017] [Accepted: 01/08/2018] [Indexed: 02/06/2023] Open
Abstract
Approximately 30% of triple-negative breast cancers (TNBCs) exhibit functional loss of the RB tumor suppressor, suggesting a target for precision intervention. Here, we use drug screens to identify agents specifically antagonized by the retinoblastoma tumor suppressor (RB) using CDK4/6 inhibitors. A number of candidate RB-synthetic lethal small molecules were identified, including anti-helmenthics, chemotherapeutic agents, and small-molecule inhibitors targeting DNA-damage checkpoints (e.g., CHK) and chromosome segregation (e.g., PLK1). Counter-screens using isogenic TNBC tumor cell lines and cell panels with varying endogenous RB statuses confirmed that therapeutic effects were robust and selective for RB loss of function. By analyzing TNBC clinical specimens, RB-deficient tumors were found to express high levels of CHK1 and PLK1. Loss of RB specifically resulted in loss of checkpoint functions governing DNA replication, yielding increased drug sensitivity. Xenograft models demonstrated RB-selective efficacy of CHK inhibitors. This study supports the possibility of selectively targeting RB loss in the treatment of TNBC.
Collapse
Affiliation(s)
- Agnieszka K Witkiewicz
- University of Arizona Cancer Center, Tucson, AZ 85724, USA; Department of Pathology, University of Arizona, Tucson, AZ 85724, USA.
| | - Sejin Chung
- University of Arizona Cancer Center, Tucson, AZ 85724, USA
| | - Rachel Brough
- CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London SW3 6JB, UK
| | - Paris Vail
- University of Arizona Cancer Center, Tucson, AZ 85724, USA
| | - Jorge Franco
- University of Arizona Cancer Center, Tucson, AZ 85724, USA; Department of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Christopher J Lord
- CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London SW3 6JB, UK
| | - Erik S Knudsen
- University of Arizona Cancer Center, Tucson, AZ 85724, USA; Department of Medicine, University of Arizona, Tucson, AZ 85724, USA.
| |
Collapse
|
23
|
Olson BM, Gamat M, Seliski J, Sawicki T, Jeffery J, Ellis L, Drake CG, Weichert J, McNeel DG. Prostate Cancer Cells Express More Androgen Receptor (AR) Following Androgen Deprivation, Improving Recognition by AR-Specific T Cells. Cancer Immunol Res 2017; 5:1074-1085. [PMID: 29051161 DOI: 10.1158/2326-6066.cir-16-0390] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 08/25/2017] [Accepted: 10/13/2017] [Indexed: 01/17/2023]
Abstract
Androgen deprivation is the primary therapy for recurrent prostate cancer, and agents targeting the androgen receptor (AR) pathway continue to be developed. Because androgen-deprivation therapy (ADT) has immmunostimulatory effects as well as direct antitumor effects, AR-targeted therapies have been combined with other anticancer therapies, including immunotherapies. Here, we sought to study whether an antigen-specific mechanism of resistance to ADT (overexpression of the AR) may result in enhanced AR-specific T-cell immune recognition, and whether this might be strategically combined with an antitumor vaccine targeting the AR. Androgen deprivation increased AR expression in human and murine prostate tumor cells in vitro and in vivo The increased expression persisted over time. Increased AR expression was associated with recognition and cytolytic activity by AR-specific T cells. Furthermore, ADT combined with vaccination, specifically a DNA vaccine encoding the ligand-binding domain of the AR, led to improved antitumor responses as measured by tumor volumes and delays in the emergence of castrate-resistant prostate tumors in two murine prostate cancer models (Myc-CaP and prostate-specific PTEN-deficient mice). Together, these data suggest that ADT combined with AR-directed immunotherapy targets a major mechanism of resistance, overexpression of the AR. This combination may be more effective than ADT combined with other immunotherapeutic approaches. Cancer Immunol Res; 5(12); 1074-85. ©2017 AACR.
Collapse
Affiliation(s)
- Brian M Olson
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Melissa Gamat
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Joseph Seliski
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Thomas Sawicki
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Justin Jeffery
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin
| | - Leigh Ellis
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - Charles G Drake
- Department of Medicine, Columbia University, New York, New York
| | - Jamey Weichert
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin.,Department of Radiology, Madison, Wisconsin
| | - Douglas G McNeel
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin.
| |
Collapse
|
24
|
Bollard J, Miguela V, Ruiz de Galarreta M, Venkatesh A, Bian CB, Roberto MP, Tovar V, Sia D, Molina-Sánchez P, Nguyen CB, Nakagawa S, Llovet JM, Hoshida Y, Lujambio A. Palbociclib (PD-0332991), a selective CDK4/6 inhibitor, restricts tumour growth in preclinical models of hepatocellular carcinoma. Gut 2017; 66:1286-1296. [PMID: 27849562 PMCID: PMC5512174 DOI: 10.1136/gutjnl-2016-312268] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 10/10/2016] [Accepted: 10/25/2016] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Advanced hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. Palbociclib, a well-tolerated and selective CDK4/6 inhibitor, has shown promising results in the treatment of retinoblastoma (RB1)-positive breast cancer. RB1 is rarely mutated in HCC, suggesting that palbociclib could potentially be used for HCC therapy. Here, we provide a comprehensive characterisation of the efficacy of palbociclib in multiple preclinical models of HCC. DESIGN The effects of palbociclib on cell proliferation, cellular senescence and cell death were investigated in a panel of human liver cancer cell lines, in ex vivo human HCC samples, in a genetically engineered mouse model of liver cancer, and in human HCC xenografts in vivo. The mechanisms of intrinsic and acquired resistance to palbociclib were assessed in human liver cancer cell lines and human HCC samples by protein and gene expression analyses. RESULTS Palbociclib suppressed cell proliferation in human liver cancer cell lines by promoting a reversible cell cycle arrest. Intrinsic and acquired resistance to palbociclib was determined by loss of RB1. A signature of 'RB1 loss of function' was found in <30% of HCC samples. Palbociclib, alone or combined with sorafenib, the standard of care for HCC, impaired tumour growth in vivo and significantly increased survival. CONCLUSIONS Palbociclib shows encouraging results in preclinical models of HCC and represents a novel therapeutic strategy for HCC treatment, alone or particularly in combination with sorafenib. Palbociclib could potentially benefit patients with RB1-proficient tumours, which account for 70% of all patients with HCC.
Collapse
Affiliation(s)
- Julien Bollard
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Verónica Miguela
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Marina Ruiz de Galarreta
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Anu Venkatesh
- Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - C Billie Bian
- Graduate School of Biomedical Sciences at Icahn School of Medicine at Mount Sinai, New York, USA
| | - Mark P Roberto
- Graduate School of Biomedical Sciences at Icahn School of Medicine at Mount Sinai, New York, USA
| | - Victoria Tovar
- Liver Cancer Translational Research Laboratory, Barcelona Clinic Liver Cancer (BCLC) Group, Liver Unit and Pathology Department, IDIBAPS, Hospital Clínic, CIBERehd, Universitat de Barcelona, Barcelona, Spain
| | - Daniela Sia
- Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Pedro Molina-Sánchez
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Christie B Nguyen
- Graduate School of Biomedical Sciences at Icahn School of Medicine at Mount Sinai, New York, USA
| | - Shigeki Nakagawa
- Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Josep M Llovet
- Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Translational Research Laboratory, Barcelona Clinic Liver Cancer (BCLC) Group, Liver Unit and Pathology Department, IDIBAPS, Hospital Clínic, CIBERehd, Universitat de Barcelona, Barcelona, Spain,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Yujin Hoshida
- Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Amaia Lujambio
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA,Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA,Graduate School of Biomedical Sciences at Icahn School of Medicine at Mount Sinai, New York, USA
| |
Collapse
|
25
|
A distinct function of the retinoblastoma protein in the control of lipid composition identified by lipidomic profiling. Oncogenesis 2017. [PMID: 28650445 PMCID: PMC5519198 DOI: 10.1038/oncsis.2017.51] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Here, by combining lipidomics with transcriptome analysis, we demonstrate that Rb depletion in mouse embryonic fibroblastss induces significant alterations in their lipid composition. We discovered that Rb depletion induced increase in lysophosphatidylserine, diacylglycerol (DAG), fatty acid (FA), acylcarnitine, phosphatidylcholine (PC), arachidonoyl ethanolamine, and decrease in phosphatidylglycerol, monoacylglycerol, without change in total lipid per protein levels. Analysis of the acyl chain composition of DAG, PC and phosphatidylserine revealed increase of saturated and mono-unsaturated acyl chains with specific carbon chain length. Consistently, we observed that Rb depletion increased the levels of fatty acids with the corresponding carbon chain length and number of carbon-carbon double bondssuch as myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0) and all forms of FA 18:1. Microarray analysis revealed that Rb depletion induced significant upregulation of enzymes involved in elongation and desaturation of fatty acids. Among these, we found that elongation of long chain fatty acid family member 6 (Elovl6) and stearoyl-CoA desaturase 1 (Scd1) are the most robustly controlled by Rb possibly through E2F and sterol regulatory element-binding protein transcription factors. Depletion of Elovl6 or Scd1 significantly suppressed colony formation, sphere formation and xenograft tumor growth of Rb-deficient tumor cells. Suppression of self-renewal by the SCD1 inhibitor was rescued upon supplementation of the mono-unsaturated fatty acids generated by this enzyme. This study suggests a novel role for Rb in suppressing the malignant progression of tumors by controlling the lipid composition.
Collapse
|
26
|
Abstract
In this review, Dyson summarizes some recent developments in pRB research and focuses on progress toward answers for the three fundamental questions that sit at the heart of the pRB literature: What does pRB do? How does the inactivation of RB change the cell? How can our knowledge of RB function be exploited to provide better treatment for cancer patients? The retinoblastoma susceptibility gene (RB1) was the first tumor suppressor gene to be molecularly defined. RB1 mutations occur in almost all familial and sporadic forms of retinoblastoma, and this gene is mutated at variable frequencies in a variety of other human cancers. Because of its early discovery, the recessive nature of RB1 mutations, and its frequency of inactivation, RB1 is often described as a prototype for the class of tumor suppressor genes. Its gene product (pRB) regulates transcription and is a negative regulator of cell proliferation. Although these general features are well established, a precise description of pRB's mechanism of action has remained elusive. Indeed, in many regards, pRB remains an enigma. This review summarizes some recent developments in pRB research and focuses on progress toward answers for the three fundamental questions that sit at the heart of the pRB literature: What does pRB do? How does the inactivation of RB change the cell? How can our knowledge of RB function be exploited to provide better treatment for cancer patients?
Collapse
|
27
|
Thwaites MJ, Cecchini MJ, Talluri S, Passos DT, Carnevale J, Dick FA. Multiple molecular interactions redundantly contribute to RB-mediated cell cycle control. Cell Div 2017; 12:3. [PMID: 28293272 PMCID: PMC5348811 DOI: 10.1186/s13008-017-0029-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/28/2017] [Indexed: 02/07/2023] Open
Abstract
Background The G1-S phase transition is critical to maintaining proliferative control and preventing carcinogenesis. The retinoblastoma tumor suppressor is a key regulator of this step in the cell cycle. Results Here we use a structure–function approach to evaluate the contributions of multiple protein interaction surfaces on pRB towards cell cycle regulation. SAOS2 cell cycle arrest assays showed that disruption of three separate binding surfaces were necessary to inhibit pRB-mediated cell cycle control. Surprisingly, mutation of some interaction surfaces had no effect on their own. Rather, they only contributed to cell cycle arrest in the absence of other pRB dependent arrest functions. Specifically, our data shows that pRB–E2F interactions are competitive with pRB–CDH1 interactions, implying that interchangeable growth arrest functions underlie pRB’s ability to block proliferation. Additionally, disruption of similar cell cycle control mechanisms in genetically modified mutant mice results in ectopic DNA synthesis in the liver. Conclusions Our work demonstrates that pRB utilizes a network of mechanisms to prevent cell cycle entry. This has important implications for the use of new CDK4/6 inhibitors that aim to activate this proliferative control network.
Collapse
Affiliation(s)
- Michael J Thwaites
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Matthew J Cecchini
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Srikanth Talluri
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Daniel T Passos
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Jasmyne Carnevale
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Frederick A Dick
- London Regional Cancer Program, London, Canada.,Children's Health Research Institute, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| |
Collapse
|
28
|
Knudsen ES, Witkiewicz AK. Defining the transcriptional and biological response to CDK4/6 inhibition in relation to ER+/HER2- breast cancer. Oncotarget 2016; 7:69111-69123. [PMID: 27564114 PMCID: PMC5342463 DOI: 10.18632/oncotarget.11588] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 08/13/2016] [Indexed: 12/31/2022] Open
Abstract
ER positive (ER+) and HER2 negative (HER2-) breast cancers are routinely treated based on estrogen dependence. CDK4/6 inhibitors in combination with endocrine therapy have significantly improved the progression-free survival of patients with ER+/HER2- metastatic breast cancer. Gene expression profiling in ER+/HER2- models was used to define the basis for the efficacy of CDK4/6 inhibitors and develop a gene expression signature of CDK4/6 inhibition. CDK4/6 inhibition robustly suppressed cell cycle progression of ER+/HER2- models and complements the activity of limiting estrogen. Chronic treatment with CDK4/6 inhibitors results in the consistent suppression of genes involved in cell cycle, while eliciting the induction of a comparable number of genes involved in multiple processes. The CDK4/6 inhibitor treatment shifted ER+/HER2- models from a high risk (luminal B) to a low risk (luminal A) molecular-phenotype using established gene expression panels. Consonantly, genes repressed by CDK4/6 inhibition are strongly associated with clinical prognosis in ER+/HER2- cases. This gene repression program was conserved in an aggressive triple negative breast cancer xenograft, indicating that this is a common feature of CDK4/6 inhibition. Interestingly, the genes upregulated as a consequence of CDK4/6 inhibition were more variable, but associated with improved outcome in ER+/HER2- clinical cases, indicating dual and heretofore unknown consequence of CDK4/6 inhibition. Interestingly, CDK4/6 inhibition was also associated with the induction of a collection of genes associated with cell growth; but unlike suppression of cell cycle genes this signaling was antagonized by endocrine therapy. Consistent with the stimulation of a mitogenic pathway, cell size and metabolism were induced with CDK4/6 inhibition but ameliorated with endocrine therapy. Together, the data herein support the basis for profound interaction between CDK4/6 inhibitors and endocrine therapy by cooperating for the suppression of cell cycle progression and limiting compensatory pro-growth processes that could contribute to therapeutic failure.
Collapse
Affiliation(s)
- Erik S. Knudsen
- Department of Medicine, University of Arizona, Tucson, AZ, USA
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, USA
| | - Agnieszka K. Witkiewicz
- Department of Medicine, University of Arizona, Tucson, AZ, USA
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ, USA
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pathology, University of Arizona, Tucson, AZ, USA
| |
Collapse
|
29
|
Muñoz-Fontela C, Mandinova A, Aaronson SA, Lee SW. Emerging roles of p53 and other tumour-suppressor genes in immune regulation. Nat Rev Immunol 2016; 16:741-750. [PMID: 27667712 DOI: 10.1038/nri.2016.99] [Citation(s) in RCA: 233] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tumour-suppressor genes are indispensable for the maintenance of genomic integrity. Recently, several of these genes, including those encoding p53, PTEN, RB1 and ARF, have been implicated in immune responses and inflammatory diseases. In particular, the p53 tumour- suppressor pathway is involved in crucial aspects of tumour immunology and in homeostatic regulation of immune responses. Other studies have identified roles for p53 in various cellular processes, including metabolism and stem cell maintenance. Here, we discuss the emerging roles of p53 and other tumour-suppressor genes in tumour immunology, as well as in additional immunological settings, such as virus infection. This relatively unexplored area could yield important insights into the homeostatic control of immune cells in health and disease and facilitate the development of more effective immunotherapies. Consequently, tumour-suppressor genes are emerging as potential guardians of immune integrity.
Collapse
Affiliation(s)
- César Muñoz-Fontela
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20251 Hamburg, Germany
| | - Anna Mandinova
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Building 149 13th Street, Charlestown, Massachusetts 02129, USA.,Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, Massachusetts 02138, USA.,Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142, USA
| | - Stuart A Aaronson
- Department of Oncological Sciences, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York 10029, USA
| | - Sam W Lee
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Building 149 13th Street, Charlestown, Massachusetts 02129, USA.,Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142, USA
| |
Collapse
|
30
|
Hutcheson J, Witkiewicz AK, Knudsen ES. The RB tumor suppressor at the intersection of proliferation and immunity: relevance to disease immune evasion and immunotherapy. Cell Cycle 2016; 14:3812-9. [PMID: 25714546 DOI: 10.1080/15384101.2015.1010922] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The retinoblastoma tumor suppressor (RB) was the first identified tumor suppressor based on germline predisposition to the pediatric eye tumor. Since these early studies, it has become apparent that the functional inactivation of RB is a common event in nearly all human malignancy. A great deal of research has gone into understanding how the loss of RB promotes tumor etiology and progression. Since malignant tumors are characterized by aberrant cell division, much of this research has focused upon the ability of RB to regulate the cell cycle by repression of proliferation-related genes. However, it is progressively understood that RB is an important mediator of multiple functions. One area that is gaining progressive interest is the emerging role for RB in regulating diverse features of immune function. These findings suggest that RB is more than simply a regulator of cellular proliferation; it is at the crossroads of proliferation and the immune response. Here we review the data related to the functional roles of RB on the immune system, relevance to immune evasion, and potential significance to the response to immune-therapy.
Collapse
Affiliation(s)
- Jack Hutcheson
- a Department of Pathology ; University of Texas Southwestern Medical Center ; Dallas , TX USA
| | - Agnieszka K Witkiewicz
- a Department of Pathology ; University of Texas Southwestern Medical Center ; Dallas , TX USA.,b Simmons Cancer Center ; University of Texas Southwestern Medical Center ; Dallas , TX USA
| | - Erik S Knudsen
- a Department of Pathology ; University of Texas Southwestern Medical Center ; Dallas , TX USA.,b Simmons Cancer Center ; University of Texas Southwestern Medical Center ; Dallas , TX USA
| |
Collapse
|
31
|
Malorni L, Piazza S, Ciani Y, Guarducci C, Bonechi M, Biagioni C, Hart CD, Verardo R, Leo AD, Migliaccio I. A gene expression signature of retinoblastoma loss-of-function is a predictive biomarker of resistance to palbociclib in breast cancer cell lines and is prognostic in patients with ER positive early breast cancer. Oncotarget 2016; 7:68012-68022. [PMID: 27634906 PMCID: PMC5356535 DOI: 10.18632/oncotarget.12010] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/03/2016] [Indexed: 01/16/2023] Open
Abstract
Palbociclib is a CDK4/6 inhibitor that received FDA approval for treatment of hormone receptor positive (HR+) HER2 negative (HER2neg) advanced breast cancer. To better personalize patients treatment it is critical to identify subgroups that would mostly benefit from it. We hypothesize that complex alterations of the Retinoblastoma (Rb) pathway might be implicated in resistance to CDK4/6 inhibitors and aim to investigate whether signatures of Rb loss-of-function would identify breast cancer cell lines resistant to palbociclib. We established a gene expression signature of Rb loss-of-function (RBsig) by identifying genes correlated with E2F1 and E2F2 expression in breast cancers within The Cancer Genome Atlas. We assessed the RBsig prognostic role in the METABRIC and in a comprehensive breast cancer meta-dataset. Finally, we analyzed whether RBsig would discriminate palbociclib-sensitive and -resistant breast cancer cells in a large RNA sequencing-based dataset. The RBsig was associated with RB1 genetic status in all tumors (p <7e-32) and in luminal or basal subtypes (p < 7e-11 and p < 0.002, respectively). The RBsig was prognostic in the METABRIC dataset (discovery: HR = 1.93 [1.5-2.4] p = 1.4e-08; validation: HR = 2.01 [1.6-2.5] p = 1.3e-09). Untreated and endocrine treated patients with estrogen receptor positive breast cancer expressing high RBsig had significantly worse recurrence free survival compared to those with low RBsig (HR = 2.37 [1.8 - 3.2] p = 1.87e-08 and HR = 2.62 [1.9- 3.5] p = 8.6e-11, respectively). The RBsig was able to identify palbociclib resistant and sensitive breast cancer cells (ROC AUC = 0,7778). Signatures of RB loss might be helpful in personalizing treatment of patients with HR+/HER2neg breast cancer. Further validation in patients receiving palbociclib is warranted.
Collapse
Affiliation(s)
- Luca Malorni
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
- “Sandro Pitigliani” Medical Oncology Department, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Silvano Piazza
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, and Functional Genomics & Bioinformatics Units, Trieste, Italy
- Bioinformatics Core Facility, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Yari Ciani
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, and Functional Genomics & Bioinformatics Units, Trieste, Italy
| | - Cristina Guarducci
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Martina Bonechi
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Chiara Biagioni
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
- “Sandro Pitigliani” Medical Oncology Department, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Christopher D. Hart
- “Sandro Pitigliani” Medical Oncology Department, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Roberto Verardo
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, and Functional Genomics & Bioinformatics Units, Trieste, Italy
| | - Angelo Di Leo
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
- “Sandro Pitigliani” Medical Oncology Department, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| | - Ilenia Migliaccio
- “Sandro Pitigliani” Translational Research Unit, Hospital of Prato-AUSL Toscana Centro, Istituto Toscano Tumori, Prato, Italy
| |
Collapse
|
32
|
Knudsen ES, McClendon AK, Franco J, Ertel A, Fortina P, Witkiewicz AK. RB loss contributes to aggressive tumor phenotypes in MYC-driven triple negative breast cancer. Cell Cycle 2015; 14:109-22. [PMID: 25602521 DOI: 10.4161/15384101.2014.967118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Triple negative breast cancer (TNBC) is characterized by multiple genetic events occurring in concert to drive pathogenic features of the disease. Here we interrogated the coordinate impact of p53, RB, and MYC in a genetic model of TNBC, in parallel with the analysis of clinical specimens. Primary mouse mammary epithelial cells (mMEC) with defined genetic features were used to delineate the combined action of RB and/or p53 in the genesis of TNBC. In this context, the deletion of either RB or p53 alone and in combination increased the proliferation of mMEC; however, the cells did not have the capacity to invade in matrigel. Gene expression profiling revealed that loss of each tumor suppressor has effects related to proliferation, but RB loss in particular leads to alterations in gene expression associated with the epithelial-to-mesenchymal transition. The overexpression of MYC in combination with p53 loss or combined RB/p53 loss drove rapid cell growth. While the effects of MYC overexpression had a dominant impact on gene expression, loss of RB further enhanced the deregulation of a gene expression signature associated with invasion. Specific RB loss lead to enhanced invasion in boyden chambers assays and gave rise to tumors with minimal epithelial characteristics relative to RB-proficient models. Therapeutic screening revealed that RB-deficient cells were particularly resistant to agents targeting PI3K and MEK pathway. Consistent with the aggressive behavior of the preclinical models of MYC overexpression and RB loss, human TNBC tumors that express high levels of MYC and are devoid of RB have a particularly poor outcome. Together these results underscore the potency of tumor suppressor pathways in specifying the biology of breast cancer. Further, they demonstrate that MYC overexpression in concert with RB can promote a particularly aggressive form of TNBC.
Collapse
Affiliation(s)
- Erik S Knudsen
- a Simmons Cancer Center; UT Southwestern ; Dallas , TX USA
| | | | | | | | | | | |
Collapse
|
33
|
Hutcheson J, Bourgo RJ, Balaji U, Ertel A, Witkiewicz AK, Knudsen ES. Retinoblastoma protein potentiates the innate immune response in hepatocytes: significance for hepatocellular carcinoma. Hepatology 2014; 60:1231-40. [PMID: 24824777 PMCID: PMC4482134 DOI: 10.1002/hep.27217] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 05/08/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Cancers mediated by viral etiology must exhibit deregulated cellular proliferation and evade immune recognition. The role of the retinoblastoma tumor suppressor (RB) pathway, which is lost at relatively high frequency in hepatocellular carcinoma (HCC), has recently been expanded to include the regulation of innate immune responsiveness. In this study we investigated the coordinate impact of RB-loss on cell cycle control and immune function in the liver. We found that RB depletion in hepatoma cells resulted in a compromised immunological response to multiple stimuli and reduced the potential of these cells to recruit myeloid cells. Viral-mediated liver-specific RB deletion in vivo led to the induction of genes associated with proliferation and cell cycle entry as well as the significant attenuation of genes associated with immune function, as evidenced by decreases in cytokine and chemokine expression, leukocyte recruitment, and hepatic inflammation. To determine if these changes in gene expression were instructive in human disease, we compared our liver-specific RB-loss gene signature to existing profiles of HCC and found that this signature was associated with disease progression and confers a worse prognosis. CONCLUSION Our data confirm that RB participates in the regulation of innate immunity in liver parenchymal cells both in vitro and in vivo and to our knowledge describes the first gene signature associated with HCC that includes both immunoregulatory and proliferative genes and that can also be attributed to the alteration of a single gene in vitro.
Collapse
Affiliation(s)
- Jack Hutcheson
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ryan J. Bourgo
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637
| | - Uthra Balaji
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Adam Ertel
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107
| | - Agnieszka K. Witkiewicz
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Erik S. Knudsen
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| |
Collapse
|
34
|
Cell cycle: mechanisms of control and dysregulation in cancer. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
35
|
Kansara M, Leong HS, Lin DM, Popkiss S, Pang P, Garsed DW, Walkley CR, Cullinane C, Ellul J, Haynes NM, Hicks R, Kuijjer ML, Cleton-Jansen AM, Hinds PW, Smyth MJ, Thomas DM. Immune response to RB1-regulated senescence limits radiation-induced osteosarcoma formation. J Clin Invest 2013; 123:5351-60. [PMID: 24231354 DOI: 10.1172/jci70559] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/05/2013] [Indexed: 12/19/2022] Open
Abstract
Ionizing radiation (IR) and germline mutations in the retinoblastoma tumor suppressor gene (RB1) are the strongest risk factors for developing osteosarcoma. Recapitulating the human predisposition, we found that Rb1+/- mice exhibited accelerated development of IR-induced osteosarcoma, with a latency of 39 weeks. Initial exposure of osteoblasts to carcinogenic doses of IR in vitro and in vivo induced RB1-dependent senescence and the expression of a panel of proteins known as senescence-associated secretory phenotype (SASP), dominated by IL-6. RB1 expression closely correlated with that of the SASP cassette in human osteosarcomas, and low expression of both RB1 and the SASP genes was associated with poor prognosis. In vivo, IL-6 was required for IR-induced senescence, which elicited NKT cell infiltration and a host inflammatory response. Mice lacking IL-6 or NKT cells had accelerated development of IR-induced osteosarcomas. These data elucidate an important link between senescence, which is a cell-autonomous tumor suppressor response, and the activation of host-dependent cancer immunosurveillance. Our findings indicate that overcoming the immune response to senescence is a rate-limiting step in the formation of IR-induced osteosarcoma.
Collapse
|
36
|
Wierstra I. The transcription factor FOXM1 (Forkhead box M1): proliferation-specific expression, transcription factor function, target genes, mouse models, and normal biological roles. Adv Cancer Res 2013; 118:97-398. [PMID: 23768511 DOI: 10.1016/b978-0-12-407173-5.00004-2] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor, which stimulates cell proliferation and exhibits a proliferation-specific expression pattern. Accordingly, both the expression and the transcriptional activity of FOXM1 are increased by proliferation signals, but decreased by antiproliferation signals, including the positive and negative regulation by protooncoproteins or tumor suppressors, respectively. FOXM1 stimulates cell cycle progression by promoting the entry into S-phase and M-phase. Moreover, FOXM1 is required for proper execution of mitosis. Accordingly, FOXM1 regulates the expression of genes, whose products control G1/S-transition, S-phase progression, G2/M-transition, and M-phase progression. Additionally, FOXM1 target genes encode proteins with functions in the execution of DNA replication and mitosis. FOXM1 is a transcriptional activator with a forkhead domain as DNA binding domain and with a very strong acidic transactivation domain. However, wild-type FOXM1 is (almost) inactive because the transactivation domain is repressed by three inhibitory domains. Inactive FOXM1 can be converted into a very potent transactivator by activating signals, which release the transactivation domain from its inhibition by the inhibitory domains. FOXM1 is essential for embryonic development and the foxm1 knockout is embryonically lethal. In adults, FOXM1 is important for tissue repair after injury. FOXM1 prevents premature senescence and interferes with contact inhibition. FOXM1 plays a role for maintenance of stem cell pluripotency and for self-renewal capacity of stem cells. The functions of FOXM1 in prevention of polyploidy and aneuploidy and in homologous recombination repair of DNA-double-strand breaks suggest an importance of FOXM1 for the maintenance of genomic stability and chromosomal integrity.
Collapse
|
37
|
Joosten SA, Fletcher HA, Ottenhoff THM. A helicopter perspective on TB biomarkers: pathway and process based analysis of gene expression data provides new insight into TB pathogenesis. PLoS One 2013; 8:e73230. [PMID: 24066041 PMCID: PMC3774688 DOI: 10.1371/journal.pone.0073230] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/18/2013] [Indexed: 12/25/2022] Open
Abstract
Biomarker host genetic signatures are considered key tools for improved early diagnosis of tuberculosis (TB) disease (development). The analysis of gene expression changes based on a limited number of genes or single study designs, however, may not be sufficient for the identification of universal diagnostic biomarker profiles. Here we propose that biological pathway and process based analyses from multiple data sets may be more relevant for identification of key pathways in TB pathogenesis, and may reveal novel candidate diagnostic TB biomarkers. A number of independent genome-wide gene expression studies have recently been performed to study expression of biomarkers for TB disease. We have integrated the results from these independent studies and performed pathway- as well as biological process-based analysis on the total data set. Interestingly, IFNα/β signalling is not the single dominant pathway in the analysis of the total dataset, but combined, functional, analysis of biomarkers suggests a strong dominant role for myeloid cell involvement in inflammation.
Collapse
Affiliation(s)
- Simone A. Joosten
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
| | | | - Tom H. M. Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
38
|
Wierstra I. FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy. Adv Cancer Res 2013; 119:191-419. [PMID: 23870513 DOI: 10.1016/b978-0-12-407190-2.00016-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.
Collapse
|
39
|
Thangavel C, Boopathi E, Ertel A, Lim M, Addya S, Fortina P, Witkiewicz AK, Knudsen ES. Regulation of miR106b cluster through the RB pathway: mechanism and functional targets. Cell Cycle 2012; 12:98-111. [PMID: 23255112 DOI: 10.4161/cc.23029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The RB pathway plays a critical role in proliferation control that is commonly subverted in tumor development. However, restoration of RB pathway function can be elicited in many tumor cells by the inhibition of CDK4/6 activity that leads to dephosphorylation of RB and subsequent repression of E2F-mediated transcription. In this context, active RB/E2F complexes inhibit the expression of a critical program of coding genes that promote cell cycle progression. However, the non-coding RNA target genes downstream from RB that could be relevant for tumor biology remain obscure. Here, miRNA gene expression profiling identified the miR106b cluster as being efficiently repressed with CDK4/6 inhibition in an E2F and RB-dependent manner. Importantly, the miR106B-cluster is intragenic of MCM7, and through a series of functional studies, the basis of MCM7 regulation and concordant expression of the miRNA species within the 106b cluster was determined. Importantly, RB-mediated repression of the 106b cluster enhances the transcript levels of p21Cip1 and PTEN. These data provide a mechanistic basis for cross-talk between the RB pathway and p21 and PTEN through the regulation of the MCM7/miR106b locus.
Collapse
|
40
|
Lemon SM, McGivern DR. Is hepatitis C virus carcinogenic? Gastroenterology 2012; 142:1274-8. [PMID: 22537433 PMCID: PMC4422399 DOI: 10.1053/j.gastro.2012.01.045] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 01/03/2012] [Accepted: 01/09/2012] [Indexed: 02/08/2023]
Abstract
Although infection with hepatitis C virus (HCV) has become a leading cause of hepatocellular carcinoma, the mechanisms by which it results in carcinogenesis remain a subject of debate. Here, we explore the possibility that HCV replication impairs cellular DNA damage responses, thereby promoting instability of the infected host cell genome, and that HCV exerts a direct cancer-promoting effect in addition to eliciting immune-mediated inflammation and apoptosis of hepatocytes contributing to hepatocellular carcinogenesis.
Collapse
|
41
|
A shared role for RBF1 and dCAP-D3 in the regulation of transcription with consequences for innate immunity. PLoS Genet 2012; 8:e1002618. [PMID: 22496667 PMCID: PMC3320600 DOI: 10.1371/journal.pgen.1002618] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 02/08/2012] [Indexed: 12/27/2022] Open
Abstract
Previously, we discovered a conserved interaction between RB proteins and the Condensin II protein CAP-D3 that is important for ensuring uniform chromatin condensation during mitotic prophase. The Drosophila melanogaster homologs RBF1 and dCAP-D3 co-localize on non-dividing polytene chromatin, suggesting the existence of a shared, non-mitotic role for these two proteins. Here, we show that the absence of RBF1 and dCAP-D3 alters the expression of many of the same genes in larvae and adult flies. Strikingly, most of the genes affected by the loss of RBF1 and dCAP-D3 are not classic cell cycle genes but are developmentally regulated genes with tissue-specific functions and these genes tend to be located in gene clusters. Our data reveal that RBF1 and dCAP-D3 are needed in fat body cells to activate transcription of clusters of antimicrobial peptide (AMP) genes. AMPs are important for innate immunity, and loss of either dCAP-D3 or RBF1 regulation results in a decrease in the ability to clear bacteria. Interestingly, in the adult fat body, RBF1 and dCAP-D3 bind to regions flanking an AMP gene cluster both prior to and following bacterial infection. These results describe a novel, non-mitotic role for the RBF1 and dCAP-D3 proteins in activation of the Drosophila immune system and suggest dCAP-D3 has an important role at specific subsets of RBF1-dependent genes. The retinoblastoma protein (pRB) is a tumor suppressor protein known for its ability to repress transcription of E2F-dependent genes and induce cell cycle arrest. We have previously shown that RB proteins in Drosophila and human cells interact with the Condensin II subunit, CAP-D3, in an E2F-independent manner. Condensins promote condensation of chomosomes in mitosis. Our previous studies suggested that the Drosophila pRB and CAP-D3 homologs, RBF1 and dCAP-D3, co-localize on DNA and may share a function in cells that never undergo mitosis. In this study, we show that one non-mitotic function shared between RBF1 and dCAP-D3 is the regulation of many non-cell-cycle-related, clustered, and cell-type-specific transcripts including a conserved family of genes that are important for the immune response in the fly. In fact, results show that normal levels of dCAP-D3 and RBF1 expression are necessary for the ability of the fly to clear infection with human bacterial pathogens. This work demonstrates that dCAP-D3 proteins can regulate a unique subset of RBF1-dependent transcripts in vivo and identifies a novel role for both RBF1 and dCAP-D3 protein in activation of innate immune genes, which may be conserved in human cells.
Collapse
|
42
|
Bourgo RJ, Thangavel C, Ertel A, Bergseid J, McClendon AK, Wilkens L, Witkiewicz AK, Wang JYJ, Knudsen ES. RB restricts DNA damage-initiated tumorigenesis through an LXCXE-dependent mechanism of transcriptional control. Mol Cell 2011; 43:663-72. [PMID: 21855804 DOI: 10.1016/j.molcel.2011.06.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 03/28/2011] [Accepted: 06/26/2011] [Indexed: 01/18/2023]
Abstract
The LXCXE peptide motif facilitates interaction between the RB tumor suppressor and a large number of cellular proteins that are expected to impinge on diverse biological processes. In vitro and in vivo analyses demonstrated that LXCXE binding function is dispensable for RB promoter association and control of basal gene expression. Dependence on this function of RB is unmasked after DNA damage, wherein LXCXE binding is essential for exerting control over E2F3 and suppressing cell-cycle progression in the presence of genotoxic stress. Gene expression profiling revealed that the transcriptional program coordinated by this specific aspect of RB is associated with progression of human hepatocellular carcinoma and poor disease outcome. Consistent with these findings, biological challenge revealed a requirement for LXCXE binding in suppression of genotoxin-initiated hepatocellular carcinoma in vivo. Together, these studies establish an essential role of the LXCXE binding motif for RB-mediated transcriptional control, response to genotoxic insult, and tumor suppression.
Collapse
Affiliation(s)
- Ryan J Bourgo
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Aparicio A, Den RB, Knudsen KE. Time to stratify? The retinoblastoma protein in castrate-resistant prostate cancer. Nat Rev Urol 2011; 8:562-8. [PMID: 21811228 DOI: 10.1038/nrurol.2011.107] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is generally held that the retinoblastoma (RB) tumor suppressor functions in multiple tissues to protect against tumor development. However, preclinical studies and analysis of tumor samples of early disease did not support an important role of RB loss in the origin of prostate cancer. By contrast, recent observations in the clinical setting and subsequent modeling of RB function indicate that the tumor suppressor has specialized roles in controlling androgen receptor expression in prostate cancer, and primarily functions to prevent progression to the castration-resistant stage of disease. Furthermore, preclinical models have now shown that loss of RB expression or functional activity decreases the effectiveness of hormone therapy, yet seems to increase sensitivity to a subset of chemotherapeutic agents. Here, the current state of knowledge regarding the implications of RB loss for prostate cancer progression will be reviewed, and potential opportunities for developing RB as a metric to predict therapeutic response will be considered.
Collapse
Affiliation(s)
- Ana Aparicio
- Department of Genitourinary Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | | | | |
Collapse
|
44
|
Thangavel C, Dean JL, Ertel A, Knudsen KE, Aldaz CM, Witkiewicz AK, Clarke R, Knudsen ES. Therapeutically activating RB: reestablishing cell cycle control in endocrine therapy-resistant breast cancer. Endocr Relat Cancer 2011; 18:333-45. [PMID: 21367843 PMCID: PMC3624623 DOI: 10.1530/erc-10-0262] [Citation(s) in RCA: 221] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The majority of estrogen receptor (ER)-positive breast cancers are treated with endocrine therapy. While this is effective, acquired resistance to therapies targeted against ER is a major clinical challenge. Here, model systems of ER-positive breast cancers with differential susceptibility to endocrine therapy were employed to define common nodes for new therapeutic interventions. These analyses revealed that cell cycle progression is effectively uncoupled from the activity and functional state of ER in these models. In this context, cyclin D1 expression and retinoblastoma tumor suppressor protein (RB) phosphorylation are maintained even with efficient ablation of ER with pure antagonists. These therapy-resistant models recapitulate a key feature of deregulated RB/E2F transcriptional control. Correspondingly, a gene expression signature of RB-dysfunction is associated with luminal B breast cancer, which exhibits a relatively poor response to endocrine therapy. These collective findings suggest that suppression of cyclin D-supported kinase activity and restoration of RB-mediated transcriptional repression could represent a viable therapeutic option in tumors that fail to respond to hormone-based therapies. Consistent with this hypothesis, a highly selective CDK4/6 inhibitor, PD-0332991, was effective at suppressing the proliferation of all hormone refractory models analyzed. Importantly, PD-0332991 led to a stable cell cycle arrest that was fundamentally distinct from those elicited by ER antagonists, and was capable of inducing aspects of cellular senescence in hormone therapy refractory cell populations. These findings underscore the clinical utility of downstream cytostatic therapies in treating tumors that have experienced failure of endocrine therapy.
Collapse
|
45
|
Ofir M, Hacohen D, Ginsberg D. MiR-15 and miR-16 are direct transcriptional targets of E2F1 that limit E2F-induced proliferation by targeting cyclin E. Mol Cancer Res 2011; 9:440-7. [PMID: 21454377 DOI: 10.1158/1541-7786.mcr-10-0344] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MicroRNAs (miR) are small noncoding RNA molecules that have recently emerged as critical regulators of gene expression and are often deregulated in cancer. In particular, miRs encoded by the miR-15a, miR-16-1 cluster seem to act as tumor suppressors. Here, we evidence that the miR-15a, miR-16-1 cluster and related miR-15b, miR-16-2 cluster comprise miRs regulated by E2F1, a pivotal transcription factor that can induce both proliferation and cell death. E2F1 is a critical downstream target of the tumor suppressor retinoblastoma (RB). The RB pathway is often inactivated in human tumors resulting in deregulated E2F activity. We show that expression levels of the 4 mature miRs, miR-15a, miR-16-1 and miR-15b, miR-16-2, as well as their precursor pri-miRNAs, are elevated upon activation of ectopic E2F1. Moreover, activation of endogenous E2Fs upregulates expression of these miRs and endogenous E2F1 binds their respective promoters. Importantly, we corroborate that miR-15a/b inhibits expression of cyclin E, the latter a key direct transcriptional target of E2F pivotal for the G(1)/S transition, raising the possibility that E2F1, miR-15, and cyclin E constitute a feed-forward loop that modulates E2F activity and cell-cycle progression. In support of this, ectopic expression of miR-15 inhibits the G(1)/S transition, and, conversely, inhibition of miR-15 expression enhances E2F1-induced upregulation of cyclin E1 levels. Furthermore, inhibition of both miR-15 and miR-16 enhances E2F1-induced G(1)/S transition. In summary, our data identify the miR-15 and miR-16 families as novel transcriptional targets of E2F, which, in turn, modulates E2F activity.
Collapse
Affiliation(s)
- Matan Ofir
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | | | | |
Collapse
|
46
|
Sharma A, Yeow WS, Ertel A, Coleman I, Clegg N, Thangavel C, Morrissey C, Zhang X, Comstock CES, Witkiewicz AK, Gomella L, Knudsen ES, Nelson PS, Knudsen KE. The retinoblastoma tumor suppressor controls androgen signaling and human prostate cancer progression. J Clin Invest 2010; 120:4478-92. [PMID: 21099110 DOI: 10.1172/jci44239] [Citation(s) in RCA: 236] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 10/13/2010] [Indexed: 12/20/2022] Open
Abstract
Retinoblastoma (RB; encoded by RB1) is a tumor suppressor that is frequently disrupted in tumorigenesis and acts in multiple cell types to suppress cell cycle progression. The role of RB in tumor progression, however, is poorly defined. Here, we have identified a critical role for RB in protecting against tumor progression through regulation of targets distinct from cell cycle control. In analyses of human prostate cancer samples, RB loss was infrequently observed in primary disease and was predominantly associated with transition to the incurable, castration-resistant state. Further analyses revealed that loss of the RB1 locus may be a major mechanism of RB disruption and that loss of RB function was associated with poor clinical outcome. Modeling of RB dysfunction in vitro and in vivo revealed that RB controlled nuclear receptor networks critical for tumor progression and that it did so via E2F transcription factor 1-mediated regulation of androgen receptor (AR) expression and output. Through this pathway, RB depletion induced unchecked AR activity that underpinned therapeutic bypass and tumor progression. In agreement with these findings, disruption of the RB/E2F/nuclear receptor axis was frequently observed in the transition to therapy resistance in human disease. Together, these data reveal what we believe to be a new paradigm for RB function in controlling prostate tumor progression and lethal tumor phenotypes.
Collapse
Affiliation(s)
- Ankur Sharma
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Ertel A, Dean JL, Rui H, Liu C, Witkiewicz AK, Knudsen KE, Knudsen ES. RB-pathway disruption in breast cancer: differential association with disease subtypes, disease-specific prognosis and therapeutic response. Cell Cycle 2010; 9:4153-63. [PMID: 20948315 DOI: 10.4161/cc.9.20.13454] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In breast cancer, inactivation of the RB tumor suppressor gene is believed to occur via multiple mechanisms to facilitate tumorigenesis. However, the prognostic and predictive value of RB status in disease-specific clinical outcomes has remained uncertain. We investigated RB pathway deregulation in the context of both ER-positive and ER-negative disease using combined microarray datasets encompassing over 900 breast cancer patient samples. Disease-specific characteristics of RB pathway deregulation were investigated in this dataset by evaluating correlation among pathway genes as well as differential expression across patient tumor populations defined by ER status. Survival analysis among these breast cancer samples demonstrates that the RB-loss signature is associated with poor disease outcome within several independent cohorts. Within the ER-negative subpopulation, the RB-loss signature is associated with improved response to chemotherapy and longer relapse-free survival. Additionally, while individual genes in the RB target signature closely reproduce its prognostic value, they also serve to predict and monitor response to therapeutic compounds, such as the cytostatic agent PD-0332991. These results indicate that the RB-loss signature expression is associated with poor outcome in breast cancer, but predicts improved response to chemotherapy based on data in ER-negative populations. While the RB-loss signature, as a whole, demonstrates prognostic and predictive utility, a small subset of markers could be sufficient to stratify patients based on RB function and inform the selection of appropriate therapeutic regimens.
Collapse
Affiliation(s)
- Adam Ertel
- Kimmel Cancer Center, Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA.
| | | | | | | | | | | | | |
Collapse
|
48
|
Chicas A, Wang X, Zhang C, McCurrach M, Zhao Z, Mert O, Dickins RA, Narita M, Zhang M, Lowe SW. Dissecting the unique role of the retinoblastoma tumor suppressor during cellular senescence. Cancer Cell 2010; 17:376-87. [PMID: 20385362 PMCID: PMC2889489 DOI: 10.1016/j.ccr.2010.01.023] [Citation(s) in RCA: 291] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 12/31/2009] [Accepted: 02/17/2010] [Indexed: 12/29/2022]
Abstract
The RB protein family (RB, p107, and p130) has overlapping and compensatory functions in cell-cycle control. However, cancer-associated mutations are almost exclusively found in RB, implying that RB has a nonredundant role in tumor suppression. We demonstrate that RB preferentially associates with E2F target genes involved in DNA replication and is uniquely required to repress these genes during senescence but not other growth states. Consequently, RB loss leads to inappropriate DNA synthesis following a senescence trigger and, together with disruption of a p21-mediated cell-cycle checkpoint, enables extensive proliferation and rampant genomic instability. Our results identify a nonredundant RB effector function that may contribute to tumor suppression and reveal how loss of RB and p53 cooperate to bypass senescence.
Collapse
Affiliation(s)
- Agustin Chicas
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Xiaowo Wang
- MOE Key Laboratory of Bioinformatics and Bioinformatics Div, TNLIST/Department of Automation, Tsinghua University, Beijing 100084, China
| | - Chaolin Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Mila McCurrach
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Zhen Zhao
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ozlem Mert
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ross A. Dickins
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Masashi Narita
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Michael Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Scott W. Lowe
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Howard Hughes Medical Institute, Cold Spring Harbor, NY 11724, USA
- To whom correspondence should be addressed, Contact information: Scott W. Lowe, Ph.D., Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor NY 11724, Phone: 516-367-8406,
| |
Collapse
|
49
|
Differential impact of tumor suppressor pathways on DNA damage response and therapy-induced transformation in a mouse primary cell model. PLoS One 2010; 5:e8558. [PMID: 20049321 PMCID: PMC2796719 DOI: 10.1371/journal.pone.0008558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 12/11/2009] [Indexed: 12/31/2022] Open
Abstract
The RB and p53 tumor suppressors are mediators of DNA damage response, and compound inactivation of RB and p53 is a common occurrence in human cancers. Surprisingly, their cooperation in DNA damage signaling in relation to tumorigenesis and therapeutic response remains enigmatic. In the context of individuals with heritable retinoblastoma, there is a predilection for secondary tumor development, which has been associated with the use of radiation-therapy to treat the primary tumor. Furthermore, while germline mutations of the p53 gene are critical drivers for cancer predisposition syndromes, it is postulated that extrinsic stresses play a major role in promoting varying tumor spectrums and disease severities. In light of these studies, we examined the tumor suppressor functions of these proteins when challenged by exposure to therapeutic stress. To examine the cooperation of RB and p53 in tumorigenesis, and in response to therapy-induced DNA damage, a combination of genetic deletion and dominant negative strategies was employed. Results indicate that loss/inactivation of RB and p53 is not sufficient for cellular transformation. However, these proteins played distinct roles in response to therapy-induced DNA damage and subsequent tumorigenesis. Specifically, RB status was critical for cellular response to damage and senescence, irrespective of p53 function. Loss of RB resulted in a dramatic evolution of gene expression as a result of alterations in epigenetic programming. Critically, the observed changes in gene expression have been specifically associated with tumorigenesis, and RB-deficient, recurred cells displayed oncogenic characteristics, as well as increased resistance to subsequent challenge with discrete therapeutic agents. Taken together, these findings indicate that tumor suppressor functions of RB and p53 are particularly manifest when challenged by cellular stress. In the face of such challenge, RB is a critical suppressor of tumorigenesis beyond p53, and RB-deficiency could promote significant cellular evolution, ultimately contributing to a more aggressive disease.
Collapse
|
50
|
Reed CA, Mayhew CN, McClendon AK, Knudsen ES. Unique impact of RB loss on hepatic proliferation: tumorigenic stresses uncover distinct pathways of cell cycle control. J Biol Chem 2009; 285:1089-96. [PMID: 19887370 DOI: 10.1074/jbc.m109.043380] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The retinoblastoma (RB) tumor suppressor pathway is disrupted at high frequency in hepatocellular carcinoma. However, the mechanisms through which RB modulates physiological responses in the liver remain poorly defined. Despite the well established role of RB in cell cycle control, the deletion of RB had no impact on the kinetics of cell cycle entry or the restoration of quiescence during the course of liver regeneration. Although these findings indicated compensatory effects from the RB-related proteins p107 and p130, even the dual deletion of RB with p107 or p130 failed to deregulate hepatic proliferation. Furthermore, although these findings suggested a modest role for the RB-pathway in the context of proliferative control, RB loss had striking effects on response to the genotoxic hepatocarcinogen diethylnitrosamine. With diethylnitrosamine, RB deletion resulted in inappropriate cell cycle entry that facilitated secondary genetic damage and further uncoupling of DNA replication with mitotic entry. Analysis of the mechanism underlying the differential impact of RB status on liver biology revealed that, while liver regeneration is associated with the conventional induction of cyclin D1 expression, the RB-dependent cell cycle entry, occurring with diethylnitrosamine treatment, was independent of cyclin D1 levels and associated with the specific induction of E2F1. Combined, these studies demonstrate that RB loss has disparate effects on the response to unique tumorigenic stresses, which is reflective of distinct mechanisms of cell cycle entry.
Collapse
Affiliation(s)
- Christopher A Reed
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | | | |
Collapse
|