The non-apoptotic function of Caspase-8 in negatively regulating the CDK9 mediated Ser2 phosphorylation of RNA Polymerase II in cervical cancer
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PROVIDER: PRJNA898610 | ENA |
REPOSITORIES: ENA
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Project description:Cervical cancer is the fourth most frequently diagnosed and fatal gynecological cancer. 15-61% of all cases metastasize and develop chemoresistance, reducing the 5-year survival of cervical cancer patients to as low as 17%. Therefore, unraveling the mechanisms contributing to metastasis is critical in developing better-targeted therapies against it. Here, we have identified a novel mechanism where nuclear Caspase-8 directly interacts with and inhibits the activity of CDK9, thereby modulating RNAPII-mediated global transcription, including those of cell-migration and -invasion-associated genes. Crucially, low Caspase-8 expression in cervical cancer patients leads to poor prognosis, higher CDK9 phosphorylation at Thr186, and increased RNAPII activity in cervical cancer cell lines and patient biopsies. Caspase-NT8 knock-out cells were also more resistant to the small-molecule CDK9 inhibitor BAY1251152 in both 2D- and 3D-culture conditions. Combining BAY1251152 with Cisplatin synergistically overcame chemoresistance of Caspase-8 deficient cervical cancer cells. Therefore, Caspase-8 expression could be a marker in chemoresistant cervical tumors, suggesting CDK9 inhibitor treatment for their sensitization to Cisplatin-based chemotherapy.
2023-03-11 | PXD038102 | Pride
Project description:Analysis of the gene expression profile of the cervical cancer cell line HeLa in the presence or absence of Caspase-8 expression. The result offered an useful insight into the altered gene expression of metastasis associated genes due to the negative regulation of RNAPII mediated gene transcription by Caspase-8
2022-11-23 | GSE217360 | GEO
Project description:Cervical cancer is the fourth most frequently diagnosed and fatal gynecological cancer. 15-61% of all cases metastasize and develop chemoresistance, reducing the 5-year survival of cervical cancer patients to as low as 17%. Therefore, unraveling the mechanisms contributing to metastasis is critical in developing better-targeted therapies against it. Here, we have identified a novel mechanism where nuclear Caspase-8 directly interacts with and inhibits the activity of CDK9, thereby modulating RNAPII-mediated global transcription, including those of cell-migration- and cell-invasion-associated genes. Crucially, low Caspase-8 expression in cervical cancer patients leads to poor prognosis, higher CDK9 phosphorylation at Thr186, and increased RNAPII activity in cervical cancer cell lines and patient biopsies. Caspase-8 knock-out cells were also more resistant to the small-molecule CDK9 inhibitor BAY1251152 in both 2D- and 3D-culture conditions. Combining BAY1251152 with Cisplatin synergistically overcame chemoresistance of Caspase-8-deficient cervical cancer cells. Therefore, Caspase-8 expression could be a marker in chemoresistant cervical tumors, suggesting CDK9 inhibitor treatment for their sensitization to Cisplatin-based chemotherapy.
| S-EPMC9674771 | biostudies-literature
Project description:Formation of the Death-Inducing Signalling Complex (DISC) initiates the extrinsic apoptotic signalling cascade. Caspase-8 and its regulator cFLIP control death signalling by binding to the receptor via DISC-bound FADD. By elucidating the function of Caspase-10, a close homologue of caspase-8, we unexpectedly found that caspase-10 negatively regulates caspase-8-mediated cell death signalling in the DISC. We demonstrate that caspase-10 inhibits the activation of caspase-8 independent of cFLIP. Furthermore, we show that caspase-8 does not compete with other tandem DED proteins such as cFLIP or caspase-10 in binding via FADD to the receptor as current models suggest. By utilizing caspase-8 knockout cells, we demonstrate that caspase-8 has to be placed upstream of both cFLIP and caspase-10 in the DISC. We further show that DISC formation and/or stability depends on caspase-8 but is independent from its enzymatic activity. Surprisingly, we identified caspase-10 to rewire DISC-signalling to NF-kB activation and cell survival. Our data are consistent with a model in which caspase-10 and cFLIP co-ordinately regulate caspase-8-mediated cell death signalling.
2016-04-20 | GSE75365 | GEO
Project description:Apoptotic Reaction Model is an ordinary differential equation model describing every species in the apoptotic cascade and trained to simulate experiments with extrinsic or intrinsic stimuli. It is based on the model introduced by Albeck et al. 2008 and contains a missing feedback between effector caspase 3 and intrinsic caspase 9 to be able to predict results from experiments with either extrinsic and intrinsic stimuli.
2021-05-26 | MODEL2105210001 | BioModels
Project description:Targeted treatment for triple-negative breast cancer (TNBC) remains an elusive clinical challenge. Cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator shown to promote growth of multiple cancers, including TNBC, and represents a potential new therapeutic target. CDK9 increases RNA Polymerase II (Pol II) activity, which facilitates sustained expression of short-lived oncogenic and anti-apoptotic proteins. However, pre-clinical evaluation of CDK9 as a therapeutic target has been hampered by the poor selectivity of existing CDK9 inhibitors (CDK9i). Here, we report a novel CDK9i; D11-8, which exhibits high potency against CDK9 (Ki = 8 nM) and displays remarkable selectivity over other CDKs and human kinases. D11-8 inhibited TNBC cell line proliferation,, induced G2/M cell cycle arrest, and increased apoptosis. Mechanistically, D11-8 inhibited CDK9; reducing Pol II phosphorylation, down-regulating expression of proto-oncogene MYC and anti-apoptotic marker MCL1, and dramatically inducing Pol II promoter-proximal pausing at MYC, G2/M checkpoint, and E2F2 target genes. D11-8 was further validated for TNBC in vivo, and inhibited TNBC cell line tumour growth without toxicity. To further elucidate the cancer cell specificity of D11-8, normal breast tissue was collected from women undergoing reduction mammoplasty surgery and treated with D11-8 ex vivo as patient-derived explants. High doses of D11-8 (2.7 µM) had no effect on the proliferative capacity of normal breast epithelial cells (Ki67 positivity), and tissues appeared histologically normal. Collectively, these data demonstrate that D11-8 effectively inhibits CDK9 in TNBC cell lines, resulting in growth inhibition without short-term toxicity.
2023-11-25 | GSE184335 | GEO
Project description:The transcriptome of 3 cutaneous melanoma cell lines treated with Control (DMSO), CDK9 inhibitor (CDKI73), BET/bromodomain and extra terminal inhibitors IBET151, or combination of both drugs was assessed using RNAseq. Dysregulation of epigenetic modifiers is a frequent event in melanoma and underlies many aspects of melanoma biology including resistance to targeted and immunotherapies. Here we report that dual targeting of BET and CDK9 proteins have synergistic effects against melanoma cells in vitro and in vivo. The BET inhibitor (IBET151) and CDK9 inhibitor (CDKI73) synergistically killed melanoma cells in vitro independent of their BRAF or NRAS mutation status. The combination of drugs markedly inhibited the growth of human melanoma C002M cells in vitro in 3D spheroids and in vivo in NSG mice compared to vehicle control and the individual drugs (p<0.05). Cell death was associated with mitochondrial depolarisation and caspase dependent apoptosis with cleavage of PARP1 as well as downregulation of anti-apoptotic proteins BCL2, BCLXL and MCL1. GSEA revealed downregulation of hallmark gene-sets associated with E2F, G2M checkpoint and c-MYC. Survival analysis showed worse prognosis with high G2M, E2F or c-MYC gene signatures suggesting biomarkers of response of BET and CDK9 inhibitors in melanoma. This novel combination of epigenetic inhibitors targets multiple downstream genes leading to cell death of melanoma cells in vitro and in vivo and warrant further investigation for treatment of melanoma in patients not responding to current therapies.
2021-02-23 | GSE167241 | GEO
Project description:CDK9 is the kinase subunit of P-TEFb that enables RNA polymerase (Pol) II to transit from promoter-proximal pausing to productive elongation. Although considerable interest exists in CDK9 as a therapeutic target, little progress has been made due to the lack of highly selective inhibitors. Here, we describe the development of i-CDK9 as such an inhibitor that potently suppresses CDK9 phosphorylation of substrates and causes genome-wide Pol II pausing. While most genes experience reduced expression, MYC and other primary response genes increase expression upon sustained i-CDK9 treatment. Essential for this increase, the bromodomain protein BRD4 captures P-TEFb from 7SK snRNP to deliver to target genes and also enhances CDK9’s activity and resistance to inhibition. Because the i-CDK9-induced MYC expression and binding to P-TEFb compensate for P-TEFb’s loss of activity, only the simultaneous inhibition of CDK9 and MYC can efficiently induce growth arrest and apoptosis of cancer cells, suggesting the potential of a combinatorial treatment strategy. We used microarrays to examine the global impact on gene expression by imhibiting CDK9 at different time durations. HeLa cell lines treated with CDK9 inhibitor at different time points
2015-06-17 | E-GEOD-60952 | biostudies-arrayexpress
Project description:Cells can survive effector caspase (caspase 3/7) activation in response to transient apoptotic stimuli, a process named anastasis. To characterize the molecular events that occur during anastasis, we performed whole transcriptome RNA sequencing of untreated, apoptotic, and recovering cells. We found that anastasis is an active, two-stage program with unique transcriptional profiles in each stage. We also identified 10 genes that specific to the early stage of anastasis.
2017-07-31 | GSE86480 | GEO
Project description:Deregulation of the MYC transcription factor is a key driver in lymphomagenesis. MYC induces global changes in gene expression that contribute to cell growth, proliferation and oncogenesis by stimulating the activity of RNA polymerases. A key feature in its ability to stimulate RNA Pol II activity is recruitment of pTEFb, an elongation factor whose catalytic core comprises CDK9/cyclin T complexes. Hence, MYC expression and function may be susceptible to CDK9 inhibition. Non-specific inhibitors of multiple CDKs have shown promise in B-cell malignancies, where their pro-apoptotic effect has been attributed to a reduction in transcription and downmodulation of short lived pro-survival proteins (e.g., Mcl-1). However, they lack a defined mechanism of action. Here we selectively targeted CDK9 in a pre-clinical study in DLBCL.
2018-04-13 | GSE113035 | GEO