HDAC5 loss impairs RB repression of oncogenic related genes and confers CDK4/6 inhibitor resistance in cancer
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ABSTRACT:
PROVIDER: PRJNA648118 | ENA |
REPOSITORIES: ENA
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Project description:The tumor suppressor protein RB acts as a transcription repressor via the interaction of its pocket domain with an L/IXCXE motif in HDAC proteins such as HDAC1. Here we demonstrated that while lacking an L/IXCXE motif, HDAC5 interacts with both RB-N (via an FXXXV motif) and RB-C segments and this interaction is diminished by RB serine-249/threonine-252 and threonine-821 phosphorylation. HDAC5 gene is frequently downregulated or deleted in human cancers such as prostate cancer. Loss of HDAC5 increases histone H3 lysine 27 acetylation (H3K27-ac) and circumvents RB-mediated repression of cell cycle-related oncogenic genes. Accordingly, HDAC5 loss confers resistance to the CDK4/6 inhibitors such as Palbociclib in prostate cancer cells in vitro and in mice, but this effect is overcome by the BET-CBP/p300 dual inhibitor NEO2734. Our findings reveal an unknown role of HDAC5 in RB-mediated histone deacetylation and gene repression and a mechanism modulating CDK4/6 inhibitor therapeutic sensitivity in cancer cells.
2021-07-24 | GSE155003 | GEO
Project description:The tumor suppressor protein RB acts as a transcription repressor via the interaction of its pocket domain with an L/IXCXE motif in HDAC proteins such as HDAC1. Here we demonstrated that while lacking an L/IXCXE motif, HDAC5 interacts with both RB-N (via an FXXXV motif) and RB-C segments and this interaction is diminished by RB serine-249/threonine-252 and threonine-821 phosphorylation. HDAC5 gene is frequently downregulated or deleted in human cancers such as prostate cancer. Loss of HDAC5 increases histone H3 lysine 27 acetylation (H3K27-ac) and circumvents RB-mediated repression of cell cycle-related oncogenic genes. Accordingly, HDAC5 loss confers resistance to the CDK4/6 inhibitors such as Palbociclib in prostate cancer cells in vitro and in mice, but this effect is overcome by the BET-CBP/p300 dual inhibitor NEO2734. Our findings reveal an unknown role of HDAC5 in RB-mediated histone deacetylation and gene repression and a mechanism modulating CDK4/6 inhibitor therapeutic sensitivity in cancer cells.
2021-07-24 | GSE155001 | GEO
Project description:HDAC5 loss impairs RB repression of oncogenic related genes and confers CDK4/6 inhibitor resistance in cancer [RNA-seq]
| PRJNA648121 | ENA
Project description:HDAC5 loss impairs RB repression of oncogenic related genes and confers CDK4/6 inhibitor resistance in cancer [ChIP-seq]
| PRJNA648127 | ENA
Project description:The retinoblastoma tumor suppressor protein (Rb) regulates early G1 phase checkpoints, including the DNA damage response, as well as cell cycle exit and differentiation. The widely accepted model of G1 cell cycle progression proposes that cyclin D:Cdk4/6 partially inactivates the Rb tumor suppressor during early G1 phase by progressive multi-phosphorylation, termed hypo-phosphorylation, resulting in release of E2F transcription factors. However, this model remains largely unproven biochemically and the biologically active form(s) of Rb remains unknown. Here we find that Rb is un-phosphorylated in G0 cells and becomes exclusively mono-phosphorylated throughout all of early G1 phase by cyclin D:Cdk4/6. Early G1 phase mono-phosphorylated Rb is composed of 14 independent isoforms that are all targeted by the E1a oncoprotein, but each shows a preferential binding pattern to specific E2F1-4 transcription factors. At the late G1 Restriction Point, cyclin E:Cdk2 inactivates Rb by a quantum hyper-phosphorylation (>12 phosphates/Rb). Cells undergoing a DNA damage response activate cyclin D:Cdk4/6 to generate mono-phosphorylated Rb that regulates global transcription. In contrast, a non-phosphorylatable ?Cdk-Rb allele was non-functional for regulating a DNA damage response, but functional for driving cell cycle exit and differentiation during myogenesis. These observations fundamentally change our understanding of G1 cell cycle progression and show that there is no progressive multi-phosphorylation or hypo-phosphorylation inactivation of Rb during early G1 phase by cyclin D:Cdk4/6. Instead, cyclin D:Cdk4/6 generates functionally active, mono-phosphorylated Rb that is the only Rb isoform present in cells during early G1 phase. Global transcriptional analysis of murine embryonic fibroblasts (MEFs) with conditional deletion of the endogenous RB gene by treatment with cell permeable TAT-Cre. Comparison to unaltered MEFs and MEFs with physiological level of exogenous wildtype or phospho-mutant RB expressed at time of RB gene deletion.
2014-04-03 | E-GEOD-56453 | biostudies-arrayexpress
Project description:Cyclin dependent kinase 4 and 6 (CDK4/6) in complex with D-type cyclins promote cell cycle entry, at least in part through phosphorylation of the retinoblastoma tumor suppressor protein (Rb). The CDK4/6-cyclin D-Rb pathway is commonly deregulated in human cancer, often through CDK4/6 or D-type cyclin overexpression, or inactivation of the CDK4/6 antagonist p16/CDKN2A. Importantly, a substantial fraction of cancers depend on continuous CDK4/6-cyclin D kinase activity and are sensitive to CDK4/6-specific inhibitors. Here, we investigate critical CDK4/6-cyclin D functions that may determine the sensitivity to CDK4/6 inhibitors, making use of the essential roles of CDK4/6 (CDK-4) and cyclin D (CYD-1) in the nematode C. elegans. In an unbiased screen, we found that simultaneous loss of C. elegans Rb (lin-35) and down-regulation of the APC/C substrate specificity factor FZR1/Cdh1 completely overcomes CDK-4/CYD-1 requirement. Furthermore, CDK-4/CYD-1 phosphorylates specific residues in the LIN-35 Rb spacer domain and FZR-1 N-terminus that correspond to inactivating phosphorylations of the human homologs. Thus, CDK-4/CYD-1 appears to promote cell cycle entry by antagonizing not only transcriptional repression by LIN-35 Rb but also protein degradation by APC/CFZR-1. Simultaneous knockdown of Rb and FZR1 in human breast cancer cells synergistically overcomes arrest by the CDK4/6-specific inhibitor PD 00332991. These results reveal APC/CFZR1 as a putative CDK4/6-Cyclin D target and important contributing factor in the response to CDK4/6-inhibitor treatment.
2016-07-05 | PXD001501 | Pride
Project description:The retinoblastoma tumor suppressor protein (Rb) regulates early G1 phase checkpoints, including the DNA damage response, as well as cell cycle exit and differentiation. The widely accepted model of G1 cell cycle progression proposes that cyclin D:Cdk4/6 partially inactivates the Rb tumor suppressor during early G1 phase by progressive multi-phosphorylation, termed hypo-phosphorylation, resulting in release of E2F transcription factors. However, this model remains largely unproven biochemically and the biologically active form(s) of Rb remains unknown. Here we find that Rb is un-phosphorylated in G0 cells and becomes exclusively mono-phosphorylated throughout all of early G1 phase by cyclin D:Cdk4/6. Early G1 phase mono-phosphorylated Rb is composed of 14 independent isoforms that are all targeted by the E1a oncoprotein, but each shows a preferential binding pattern to specific E2F1-4 transcription factors. At the late G1 Restriction Point, cyclin E:Cdk2 inactivates Rb by a quantum hyper-phosphorylation (>12 phosphates/Rb). Cells undergoing a DNA damage response activate cyclin D:Cdk4/6 to generate mono-phosphorylated Rb that regulates global transcription. In contrast, a non-phosphorylatable ?Cdk-Rb allele was non-functional for regulating a DNA damage response, but functional for driving cell cycle exit and differentiation during myogenesis. These observations fundamentally change our understanding of G1 cell cycle progression and show that there is no progressive multi-phosphorylation or hypo-phosphorylation inactivation of Rb during early G1 phase by cyclin D:Cdk4/6. Instead, cyclin D:Cdk4/6 generates functionally active, mono-phosphorylated Rb that is the only Rb isoform present in cells during early G1 phase.
2014-04-03 | GSE56453 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2021-07-24 | GSE155004 | GEO
Project description:CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Through a genome-wide CRISPR screen, we identified protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/RB1-knockout (RBKO) breast cancer cells. Inhibition of PRMT5 blocked the G1-to-S transition in the cell cycle independent of RB, leading to growth arrest in RBKO cells. Proteomics analysis uncovered fused in sarcoma (FUS) as a downstream effector of PRMT5. Inhibition of PRMT5 resulted in dissociation of FUS from RNA polymerase II (Pol II), which led to Ser2 Pol II hyperphosphorylation, intron retention, and subsequent downregulation of proteins involved in DNA synthesis. Furthermore, treatment with the PRMT5 inhibitor pemrametostat and a selective ER degrader fulvestrant synergistically inhibited growth of ER+/RB-deficient cell-derived and patient-derived xenografts. These findings highlight the potential of dual ER and PRMT5 blockade as a novel therapeutic strategy to overcome resistance to CDK4/6i in ER+/RB-deficient breast cancer.
2023-07-11 | GSE236499 | GEO
Project description:CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Through a genome-wide CRISPR screen, we identified protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/RB1-knockout (RBKO) breast cancer cells. Inhibition of PRMT5 blocked the G1-to-S transition in the cell cycle independent of RB, leading to growth arrest in RBKO cells. Proteomics analysis uncovered fused in sarcoma (FUS) as a downstream effector of PRMT5. Inhibition of PRMT5 resulted in dissociation of FUS from RNA polymerase II (Pol II), which led to Ser2 Pol II hyperphosphorylation, intron retention, and subsequent downregulation of proteins involved in DNA synthesis. Furthermore, treatment with the PRMT5 inhibitor pemrametostat and a selective ER degrader fulvestrant synergistically inhibited growth of ER+/RB-deficient cell-derived and patient-derived xenografts. These findings highlight the potential of dual ER and PRMT5 blockade as a novel therapeutic strategy to overcome resistance to CDK4/6i in ER+/RB-deficient breast cancer.
2023-07-11 | GSE236497 | GEO