SMAD2 binding regions in estrogen receptor-positive breast cancer cell line, T47D
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE117495 | GEO | 2018/10/23
REPOSITORIES: GEO
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Project description:Inhibitors for cyclin-dependent kinase (CDK) 4 and CDK6 have been established as effective therapeutic options for hormone receptor (HR)-positive, HER2-negative advanced breast cancer. Although the CDK4/6 inhibitors mainly target the cyclin D-CDK4/6-retinoblastoma tumor suppressor protein (RB) axis, little is known about clinical impact of inhibiting phosphorylation of other CDK4/6 target proteins. Here, we have focused on other CDK4/6 targets, SMAD proteins. We showed that a CDK4/6 inhibitor Palbociclib and Activin-SMAD2 signaling cooperatively inhibited cell cycle progression of a luminal-type breast cancer cell line T47D. Mechanistically, Palbociclib enhanced SMAD2 binding to the genome through inhibiting linker phosphorylation of the SMAD2 protein by CDK4/6. Comparison of the SMAD2 ChIP-seq data of T47D with those of a triple-negative breast cancer cell line Hs578T indicated that Palbociclib augments different SMAD2-mediated program defined based on types of cells, and enhances SMAD2 binding to the target regions on the genome without affecting its binding pattern. Collectively, the CDK4/6 inhibitor facilitates the cytostatic effects of Activin-SMAD2, while it also enhances its tumor promoting effects depending on types of breast cancer.
2018-10-23 | GSE117496 | GEO
Project description:RNA-seq was performed to compare the transcriptional programmes of A375 cells treated with Palbociclib or GSK3326595 compared to untreated cells Cyclin dependent kinase 4/6 (CDK4/6) inhibitors are an established treatment in estrogen receptor positive breast cancer and are currently in clinical development in melanoma; a tumour that exhibits high rates of CDK4 activation. We analyzed melanoma cells with acquired resistance to the CDK4/6 inhibitor palbociclib, and demonstrated that palbociclib-mediated inhibition of PRMT5 is essential for sensitivity to CDK4/6 inhibitors. Mechanistically, by inhibiting PRMT5 activity, palbociclib alters MDM4 pre-mRNA splicing leading to decreased MDM4 protein expression and subsequent p53 activation. In turn, p53 increases p21 leading to inhibition of CDK2, the main kinase substituting for CDK4/6 and a key driver of resistance to palbociclib. Loss of the ability of palbociclib to regulate the PRMT5-MDM4 axis leads to resistance. Importantly, combining palbociclib with the PRMT5 inhibitor GSK3326595 enhances the efficacy of palbociclib in treatment naïve and resistant models and also delays the emergence of resistance. Our studies have uncovered a novel mechanism of action of CDK4/6 inhibitors in regulating the MDM4 oncogene and the tumor suppressor, p53. Furthermore, we have established that palbociclib inhibition of the PRMT5-MDM4 axis is essential for robust melanoma cell sensitivity and provide pre-clinical evidence that co-inhibition of CDK4/6 and PRMT5 is an effective and well tolerated therapeutic strategy. Overall our data provides a strong rationale for further investigation of novel combinations of CDK4/6 and PRMT5 inhibitors in not only melanoma but other tumour types including breast, pancreatic and esophageal carcinoma.
2019-08-23 | GSE133568 | GEO
Project description:RNA-seq was performed to compare the transcriptional programmes of palbociclib-resistant A375 and CHL1 cells compared to their parental counterparts Cyclin dependent kinase 4/6 (CDK4/6) inhibitors are an established treatment in estrogen receptor positive breast cancer and are currently in clinical development in melanoma; a tumour that exhibits high rates of CDK4 activation. We analyzed melanoma cells with acquired resistance to the CDK4/6 inhibitor palbociclib, and demonstrated that palbociclib-mediated inhibition of PRMT5 is essential for sensitivity to CDK4/6 inhibitors. Mechanistically, by inhibiting PRMT5 activity, palbociclib alters MDM4 pre-mRNA splicing leading to decreased MDM4 protein expression and subsequent p53 activation. In turn, p53 increases p21 leading to inhibition of CDK2, the main kinase substituting for CDK4/6 and a key driver of resistance to palbociclib. Loss of the ability of palbociclib to regulate the PRMT5-MDM4 axis leads to resistance. Importantly, combining palbociclib with the PRMT5 inhibitor GSK3326595 enhances the efficacy of palbociclib in treatment naïve and resistant models and also delays the emergence of resistance. Our studies have uncovered a novel mechanism of action of CDK4/6 inhibitors in regulating the MDM4 oncogene and the tumor suppressor, p53. Furthermore, we have established that palbociclib inhibition of the PRMT5-MDM4 axis is essential for robust melanoma cell sensitivity and provide pre-clinical evidence that co-inhibition of CDK4/6 and PRMT5 is an effective and well tolerated therapeutic strategy. Overall our data provides a strong rationale for further investigation of novel combinations of CDK4/6 and PRMT5 inhibitors in not only melanoma but other tumour types including breast, pancreatic and esophageal carcinoma.
2019-08-23 | GSE133567 | GEO
Project description:CDK4/6 inhibition is the standard of care for estrogen receptor positive (ER+) breast cancer, although cytostasis is frequently observed, and new treatment strategies that enhance efficacy are required. We performed a genome-wide CRISPR screen to identify genetic determinants of CDK4/6 inhibitors sensitivity. Multiple genes involved in oxidative stress and ferroptosis modulated palbociclib sensitivity. Depletion or inhibition of GPX4 increased sensitivity to palbociclib in ER+ breast cancer models, and sensitised triple negative breast cancer models to palbociclib, with GPX4 null xenografts being highly sensitive to palbociclib. Palbociclib induced oxidative stress and disordered lipid metabolism with lipid peroxidation, leading to a ferroptosis-sensitive state. Lipid peroxidation relied on a peroxisome AGPAT3-dependent pathway in ER+ breast cancer models, rather than the classical ACSL4 pathway. Our data demonstrate that CDK4/6 inhibition creates vulnerability to ferroptosis that could be exploited through combination with GPX4 inhibitors, enhancing sensitivity to CDK4/6 inhibition in breast cancer.
2023-06-20 | PXD043133 | Pride
Project description:We performed SMAD2 ChIP-seq analysis in T47D cells with/without Palbociclib treatment. To validate whether the changes in SMAD2 binding to the genome indeed resulted in changes in target gene expression, we performed RNA-seq transcriptome analyses in T47D with/without ActA stimulation and Palbo treatment.
2018-10-23 | GSE117497 | GEO
Project description:Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are approved for breast cancer treatment and show activity against other malignancies, including KRAS-mutant non-small cell lung cancer (NSCLC). However, the clinical efficacy of CDK4/6 inhibitors is limited due to frequent drug resistance and their largely cytostatic effects. Through a genome-wide cDNA screen, we identified that bromodomain-containing protein 4 (BRD4) overexpression conferred resistance to the CDK4/6 inhibitor palbociclib in KRAS-mutant NSCLC cells. Inhibition of BRD4, either by RNA interference or small-molecule inhibitors, synergized with palbociclib to induce senescence in NSCLC cells and tumors, and the combination prolonged survival in a KRAS-mutant NSCLC mouse model. Mechanistically, BRD4-inhibition enhanced cell cycle arrest and reactive oxygen species (ROS) accumulation, both of which are necessary for senescence induction; this in turn elevated GPX4, a peroxidase that suppresses ROS-triggered ferroptosis. Consequently, GPX4 inhibitor treatment selectively induced ferroptotic cell death in the senescent cancer cells, resulting in tumor regression. Co-targeting CDK4/6 and BRD4 also promoted senescence and ferroptosis vulnerability in pancreatic and breast cancer cells. Together, these findings reveal therapeutic vulnerabilities and effective combinations to enhance the clinical utility of CDK4/6 inhibitors.
2024-01-26 | GSE253204 | GEO
Project description:Intrinsic or acquired resistance to clinically approved CDK4/6 inhibitors have emerged as a major obstacle that hinders their utility beyond ER+ breast cancer. Palbociclib-sensitive ER+ breast cancer models and pancreatic ductal adenocarcinoma (PDAC) models were employed to identify functional determinants of response. In all models tested the activation of RB and inhibition of CDK2 activity emerged as determinants of sensitivity. While depleting CDK4 and 6 was sufficient to limit proliferation in specific resistance setting, RB loss renders cells completely CDK4/6 independent. The main down-stream target in this context is the activation status of CDK2 which is suppressed with CDK4/6 inhibition in an RB-dependent fashion. The P27KIP1 protein levels are associated with plasticity/rigidity of the cell cycle and correlates with sensitivity to CDK4/6 inhibiion. Exogenous overexpression and pharmacological induction of P27KIP1 by targeting the MEK/ERK pathway enhances the cytostatic effect of palbociclib. Similar to cell-culture data, in vivo experiments revealed that combination treatment of palbociclib and trametinib in mice bearing PDAC PDXs elicited a robust anti-proliferative effect with a corresponding increase in p27 expression. Mice bearing MCF7 xenografts displayed a durable response in the presence of palbociclib; however, over the course of treatment few cells begin to evade the negative cell-cycle regulation. Based on multispectral staining, the MCF7 tumor cells that underwent RB inactivation in the presence of palbociclib harbored low p27 expression. Finally, we demonstrate that the cell-cycle plasticity that enables tumor models to evade the palbociclib mediated RB activation could be potently targeted using a clinically applicable CDK2 inhibitor.
2020-06-30 | GSE146788 | GEO
Project description:Cyclin-dependent kinases 4 and 6 (CDK4/6) are essential drivers of the cell cycle and are also critical for the initiation and progression of diverse malignancies. Pharmacological inhibitors targeting CDK4/6 have demonstrated significant activity against various tumor types such as breast cancer. However, resistance to CDK4/6 inhibitors (CDK4/6i) (such as palbociclib) remains an immense obstacle in clinical and the underlying mechanisms have not been fully understood. Using quantitative high-throughput combinational screen (qHTCS) and genomic sequencing, we report that the Microphthalmia-associated transcription factor (MITF), was significantly elevated in palbociclib-resistance cells. Inhibition of MITF can enhance the therapeutic efficacy of Palbociclib and surmount Palbociclib resistance both in vitro and in vivo. Mechanistically, we found that O-GlcNAc transferase (OGT) modifies MITF with O-GlcNAcylation at Serine 49 (Ser49) within its nuclear localization signal (NLS), thereby promoting MITF binding to importin α/ β and facilitating its nuclear transportation, which is crucial in regulating senescence. Significantly, clinical studies also confirm that MITF was elevated in palbociclib-resistance patients. Collectively, these results reveal a previously unrecognized mechanism by which MITF-mediated palbociclib resistance, and provide valuable insights for the development of innovative therapeutic strategies in future clinical contexts.
2023-10-10 | GSE234515 | GEO
Project description:Cyclin-dependent kinases 4 and 6 (CDK4/6) are essential drivers of the cell cycle and are also critical for the initiation and progression of diverse malignancies. Pharmacological inhibitors targeting CDK4/6 have demonstrated significant activity against various tumor types such as breast cancer. However, resistance to CDK4/6 inhibitors (CDK4/6i) (such as palbociclib) remains an immense obstacle in clinical and the underlying mechanisms have not been fully understood. Using quantitative high-throughput combinational screen (qHTCS) and genomic sequencing, we report that the Microphthalmia-associated transcription factor (MITF), was significantly elevated in palbociclib-resistance cells. Inhibition of MITF can enhance the therapeutic efficacy of Palbociclib and surmount Palbociclib resistance both in vitro and in vivo. Mechanistically, we found that O-GlcNAc transferase (OGT) modifies MITF with O-GlcNAcylation at Serine 49 (Ser49) within its nuclear localization signal (NLS), thereby promoting MITF binding to importin α/ β and facilitating its nuclear transportation, which is crucial in regulating senescence. Significantly, clinical studies also confirm that MITF was elevated in palbociclib-resistance patients. Collectively, these results reveal a previously unrecognized mechanism by which MITF-mediated palbociclib resistance, and provide valuable insights for the development of innovative therapeutic strategies in future clinical contexts.
2023-10-10 | GSE234514 | GEO
Project description:Cyclin dependent kinase 4/6 inhibitors (CDK4/6i) lead to cell-cycle arrest but also trigger T cell-mediated immunity, which might be mediated by the qualitative and quantitative changes in human leukocyte antigen (HLA) ligands on the cancer cell surface. We investigated the effects of CDK4/6i, Abemaciclib and Palbociclib, on the immunopeptidome at subclinical, non-toxic, levels in breast cancer cell lines by biochemical isolation and identification of HLA ligands followed by network analyses. This treatment led to upregulation of cell surface HLA and revealed hundreds of induced HLA ligands in breast cancer cell lines. These new ligands were significantly enriched for peptides derived from proteins involved in the “G1/S phase transition of cell cycle” including HLA ligands from CDK4/6, Cyclin D1 and the 26S regulatory proteasomal subunit 4 (PSMC1). Interestingly, peptides from this essential biological process, that is targeted by Abemaciclib and Palbociclib, were predicted to be the most likely to induce a T cell response within the group of all induced HLA ligands when compared to HLA ligands from the DMSO-treated group. In strong contrast, peptides induced by solely one of the drugs had a lower T cell recognition score compared to the DMSO control suggesting that the observed effect is class dependent. This general hypothesis was exemplified by a peptide from PSMC1 which was among the HLA ligands with highest prediction scores and which elicited a T cell response in healthy donors. Overall, these data demonstrate that CDK4/6i treatment gives rise to drug-induced HLA ligands, that have the highest chance for being recognized by T cells if they are derived from the inhibited process of G1/S phase transition, thus providing evidence that inhibition of a distinct cellular process leads to increased presentation of the involved proteins that may be targeted by immunotherapeutic agents.
2021-09-10 | PXD024965 | Pride