RB-loss determines selective resistance and novel vulnerabilities in breast cancer modelsRB loss
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE199919 | GEO | 2022/06/13
REPOSITORIES: GEO
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Project description:The retinoblastoma tumor suppressor (RB1) plays a critical role in coordinating multiple pathways that impact on tumor initiation, disease progression, and therapeutic responses. Here we interrogated the effect of CDK4/6 inhibitor in combination with mTOR inhibtor. Also, we interrogtaed the efffect of AURK and WEE1 inhibition in ER+ breast cacner models While the RB-pathway has been purported to exhibit multiple mutually exclusive events, only RB1 is mutually exclusive with multiple genetic events that deregulate CDK4/6 activity. Using an isogenic ER+ breast cancer model with targeted RB1 deletion, we identified gene expression features that link CDK4/6 activity and RB-dependency (CDK4/6-RB integrated signature). We also investigated the role of RB on apoptotic pathway. Single copy loss on chromosome 13q encompassing the RB1 locus is prevalent in many cancers, and is associated with reduced expression of multiple genes on 13q including RB1, and inversely related to the CDK4/6-RB integrated signature supporting a genetic cause/effect relationship. To probe the broader implications on tumor biology, we investigated genes that are positively and inversely correlated with the CDK4/6-RB integrated signature. This approach defined tumor-specific pathways that could represent new therapeutic vulnerabilities associated with RB-pathway activity.
2021-08-31 | GSE182631 | GEO
Project description:The retinoblastoma tumor suppressor (RB1) plays a critical role in coordinating multiple pathways that impact on tumor initiation, disease progression, and therapeutic responses. Here we interrogated the TCGA pan-cancer data collection to probe fundamental molecular features associated with the RB-pathway across 31 tumor-types. While the RB-pathway has been purported to exhibit multiple mutually exclusive events, only RB1 is mutually exclusive with multiple genetic events that deregulate CDK4/6 activity. Using an isogenic ER+ breast cancer model with targeted RB1 deletion, we identified gene expression features that link CDK4/6 activity and RB-dependency (CDK4/6-RB integrated signature). This gene expression signature is associated with prognosis across a spectrum of tumors that exhibit average lower signature value indicative of more indolent diseases. Single copy loss on chromosome 13q encompassing the RB1 locus is prevalent in many cancers, and is associated with reduced expression of multiple genes on 13q including RB1, and inversely related to the CDK4/6-RB integrated signature supporting a genetic cause/effect relationship. To probe the broader implications on tumor biology, we investigated genes that are positively and inversely correlated with the CDK4/6-RB integrated signature. This approach defined tumor-specific pathways that could represent new therapeutic vulnerabilities associated with RB-pathway activity.
2020-03-02 | GSE145316 | GEO
Project description:The retinoblastoma (Rb) protein is a potent tumor suppressor which is known to negatively regulate the cell cycle as well as tumor progression. Phosphorylated Rb protein (pRb) has been demonstrated to be in-charge for the key G1 checkpoint, blocking entry into S-phase and thereby the cell growth. This study was designed to capture interacting protein partners of Rb1 as the cell cycle progresses. Rb1 expressing HEK-293 cells were cultured in light, medium and heavy SILAC labels to capture the changes in Rb1 interactome as the cell cycle progressed from G0 to G1S and then to G2 phase, respectively. This data might help in understanding the cell cycle regulatory effect of Rb1 protein and complement the available information on its interacting partners.
2017-09-14 | PXD007708 | Pride
Project description:Retinoblastoma (Rb) is a deadly childhood eye cancer that is classically initiated by inactivation of the RB1 tumor suppressor. Clinical management continues to rely on nonspecific chemotherapeutic agents that are associated with treatment resistance and toxicity. Here, we analyzed 103 whole exomes, 16 whole transcriptomes, 5 single-cell transcriptomes, and 4 whole genomes from primary Rb tumors to identify novel Rb dependencies. Several recurrent genomic aberrations implicate estrogen-related receptor gamma (ESRRG) in Rb pathogenesis. RB1 directly interacts with and inhibits ESRRG, and RB1 loss uncouples ESRRG from negative regulation. ESRRG regulates genes involved in retinogenesis and oxygen metabolism in Rb cells. ESRRG is preferentially expressed in hypoxic Rb cells in vivo. Depletion or inhibition of ESRRG causes marked Rb cell death which is exacerbated in hypoxia. These findings reveal a novel dependency of Rb cells on ESRRG, and they implicate ESRRG as a potential therapeutic vulnerability in Rb.
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Project description:The retinoblastoma protein (RB) is preferentially lost in the progression to castrate resistant prostate cancer (CRPC). However, the alterations associated with such loss have been scantly described. The current study aims to provide molecular mechanisms underlying Rb loss-driven CRPC phenotypes
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Project description:The retinoblastoma (RB) tumor suppressor is functionally inactivated in a wide range of human tumors where this inactivation promotes tumorigenesis in part by allowing uncontrolled proliferation. RB has been extensively studied, but its mechanisms of action in normal and cancer cells remain only partly understood. Here we describe a new mouse model to investigate the consequences of RB loss and its re-activation in vivo. In these mice, induction of shRNA molecules targeting RB for knock-down results in the development of phenotypes similar to RB knock-out mice, including the development of pituitary and thyroid tumors. Re-expression of RB leads to cell cycle arrest in cancer cells and repression of transcriptional programs driven by E2F activity. Thus, continuous RB loss is required for the maintenance of tumor phenotypes initiated by loss of RB, and this new mouse model will provide a new platform to investigate RB function in vivo.
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Project description:The retinoblastoma protein (RB) is preferentially lost in the progression to castrate resistant prostate cancer (CRPC). However, the alterations associated with such loss have been scantly described. The current study aims to provide molecular mechanisms underlying Rb loss-driven CRPC phenotypes.
2018-02-22 | GSE94958 | GEO
Project description:Genome instability is a characteristic of malignant cells, however, evidence for its contribution to tumorigenesis has been enigmatic. In this study we demonstrate that a complex containing the retinoblastoma protein, E2F1, and Condensin II localizes to major satellite repeats at pericentromeres. In the absence of this complex, this genomic region fails to properly replicate and H2AX phosphorylation at pericentromeric repeats is increased. Our data indicates that these lesions contribute to defective chromosome segregation in the ensuing mitosis. Surprisingly, loss of even one copy of the retinoblastoma gene was sufficient to reduce recruitment of Condensin II to pericentromeres and cause this phenotype. Furthermore, we determined that human RB1 mutation status in cancers of mesenchymal origin correlated with copy number variation, chromosomal gains and losses, as well as chromothriptic rearrangements. Importantly, the magnitude of these chromosomal abnormalities was indistinguishable between RB1+/- and RB1-/- genotypes. Lastly, using gene-targeted mice we determined that mutation of just one copy of the murine Rb1 gene causes sarcomas and lymphomas with increased chromosome copy number variation. Our study connects replication stress with a number of common chromosomal abnormalities in cancer through a dosage sensitive complex present at pericentromeric repeats. γH2AX localization was studied in four different genotypes: Rb+/+, RbΔL/+, RbΔL/ΔL, and Rb-/-. As a control, input from the ChIP experiment was also sequenced. The γH2AX antibody used was supplied by Millipore (catalog number 05-636, and lot number 2116620).
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Project description:The reprogramming of differentiated cells to an embryonic stem cell-like state provides a powerful system to explore fundamental mechanisms of development, including how mammalian cells establish and maintain pluripotency and long-term self-renewal capability. Based on the similarities between embryonic stem cells and cancer cells, we investigated the potential role of the retinoblastoma tumor suppressor and cell cycle regulator RB in the reprogramming of fibroblasts into induced pluripotent stem cells (iPS cells). Herein we demonstrate that loss of RB function leads to both an acceleration of the reprogramming process and the generation of more iPS clones from fibroblasts. This effect is largely due to a restrictive role for RB at the early stages of reprogramming. Surprisingly, however, RB inactivation does not enhance the formation of iPS clones by accelerating the proliferation of cells undergoing reprogramming. Rather, a genome-wide investigation of RB targets indicates that RB binds to regulatory regions of pluripotency genes such as Sox2 and Oct4 and contributes to their full repression in differentiated cells. This effect correlates with the maintenance of a repressive chromatin structure at these loci. Accordingly, Rb-deficient fibroblasts can be reprogrammed into iPS cells even in the absence of exogenous Sox2, which is normally required to initiate reprogramming from fibroblasts. These experiments identify a novel barrier in the reprogramming process, mainly the repression of certain pluripotency genes such as Sox2 by RB, which provides a new link between tumor suppressor mechanisms and cellular reprogramming. RNAseq from MEFs with 2 biological replicates (save CP), Rb ChIPseq from MEFs with 2 biological replicates, Histone H3 modification ChIPseq from MEFs with 1 biological replicate
2014-11-13 | E-GEOD-40594 | biostudies-arrayexpress
Project description:Expression analysis of wild-type SAOS cells and SAOS cells transiently transfected with RB, SMYD2, or RB and SMYD2. Four samples of wild-type, rb1, smyd2 and rb1-smyd2 were analyzed on the Human Genome U133 Plus 2.0 array.
2011-01-01 | E-GEOD-22842 | biostudies-arrayexpress