Similar Datasets
Project description:In order to establish a strict p53-dependent gene expression profile, p53 negative clones were derived from two TP53+/+ and two TP53-/mut t(4;14) human myeloma cell lines (HMCLs) using CRISPR/Cas9 technology. From the 17 dysregulated genes shared between the 6 clones from the two TP53+/+ myeloma cell lines, we established a 13-gene functional p53 score, involving genes downregulated on p53-silencing. This functional score allowed us to segregate clones, myeloma cell lines and patients’ samples according to the presence or absence of a single or double hit in TP53 gene i.e., chromosomal deletion and/or mutation. The score also distinguished 1,162 cell lines from hematological and solid cancers according to hits in TP53. Moreover, the 13-gene score was predictive of overall survival in two independent cohorts of patients. Among the 13 genes, we showed that p53-regulated BAX expression correlated to, and directly impacted, the MCL1 BH3 mimetic S63845 sensitivity of myeloma cells by modulating the amount of MCL1-BAX complexes. Resistance to cell death induced by p53-silencing was overcome by combining S63845 with venetoclax, although the synergy was significantly lower in p53-deficient versus -proficient clones and patients’ samples. Finally, by using scRNAseq analysis, we further showed in patients’ bone marrow samples that myeloma cells surviving to the BH3 mimetic combination had an about 3-fold lower p53 score. This data established a functional p53 score and showed that p53-mediating BAX expression greatly impacts mitochondria-mediated cell death in myeloma cells.
2024-04-04 | GSE245162 | GEO
Project description:In order to establish a strict p53-dependent gene expression profile, p53 negative clones were derived from two TP53+/+ and two TP53-/mut t(4;14) human myeloma cell lines (HMCLs) using CRISPR/Cas9 technology. From the 17 dysregulated genes shared between the 6 clones from the two TP53+/+ myeloma cell lines, we established a 13-gene functional p53 score, involving genes downregulated on p53-silencing. This functional score allowed us to segregate clones, myeloma cell lines and patients’ samples according to the presence or absence of a single or double hit in TP53 gene i.e., chromosomal deletion and/or mutation. The score also distinguished 1,162 cell lines from hematological and solid cancers according to hits in TP53. Moreover, the 13-gene score was predictive of overall survival in two independent cohorts of patients. Among the 13 genes, we showed that p53-regulated BAX expression correlated to, and directly impacted, the MCL1 BH3 mimetic S63845 sensitivity of myeloma cells by modulating the amount of MCL1-BAX complexes. Resistance to cell death induced by p53-silencing was overcome by combining S63845 with venetoclax, although the synergy was significantly lower in p53-deficient versus -proficient clones and patients’ samples. Finally, by using scRNAseq analysis, we further showed in patients’ bone marrow samples that myeloma cells surviving to the BH3 mimetic combination had an about 3-fold lower p53 score. This data established a functional p53 score and showed that p53-mediating BAX expression greatly impacts mitochondria-mediated cell death in myeloma cells.
2024-04-04 | GSE245049 | GEO
Project description:A p53 score derived from TP53 CRISPR/Cas9 HMCLs predicts survival and reveals major role of BAX in BH3 mimetics response
| PRJNA1027275 | ENA
Project description:A p53 score derived from TP53 CRISPR/Cas9 HMCLs predicts survival and reveals major role of BAX in BH3 mimetics response [1]
| PRJNA1026858 | ENA
Project description:A p53 score derived from TP53 CRISPR/Cas9 HMCLs predicts survival and reveals major role of BAX in BH3 mimetics response [2]
| PRJNA1027285 | ENA
Project description:TP53-mutant acute myeloid leukemia (AML) respond poorly to currently available treatments, including venetoclax-based drug combinations and pose a major therapeutic challenge. Analyses of RNA sequencing and reverse phase protein array datasets revealed significantly lower BAX RNA and protein levels in TP53-mutant compared to TP53-wild-type (WT) AML, a finding confirmed in isogenic CRISPR-generated TP53-knockout and -mutant AML. The response to either BCL-2 (venetoclax) or MCL-1 (AMG176) inhibition was BAX-dependent and much reduced in TP53-mutant compared to TP53-WT cells, while the combination of two BH3 mimetics effectively activated BAX, circumventing survival mechanisms in cells treated with either BH3 mimetic, and synergistically induced cell death in TP53-mutant AML and stem/progenitor cells. The BH3 mimetic-driven stress response and cell death patterns after dual inhibition were largely independent of TP53 status and affected by apoptosis induction. Co-targeting, but not individual targeting of BCL-2 and MCL-1 in mice xenografted with TP53-WT and TP53-R248W Molm13 cells suppressed both TP53-WT and TP53-mutant cell growth and significantly prolonged survival. Our results demonstrate that co-targeting BCL-2 and MCL-1 overcomes BAX deficiency-mediated resistance to individual BH3 mimetics in TP53-mutant cells, thus shifting cell fate from survival to death in TP53-deficient and -mutant AML. This concept warrants clinical evaluation.
| S-EPMC10123065 | biostudies-literature
Project description:Inhibition of prosurvival BCL2 family members can induce autophagy, but the mechanism is controversial. We have provided genetic evidence that BCL2 family members block autophagy by inhibiting BAX and BAK1, but others have proposed they instead inhibit BECN1. Here we confirm that small molecule BH3 mimetics can induce BAX- and BAK1-independent MAP1LC3B/LC3B lipidation, but this only occurred at concentrations far greater than required to induce apoptosis and dissociate canonical BH3 domain-containing proteins that bind more tightly than BECN1. Because high concentrations of a less-active enantiomer of ABT-263 also induced BAX- and BAK1-independent LC3B lipidation, induction of this marker of autophagy appears to be an off-target effect. Indeed, robust autophagic flux was not induced by BH3 mimetic compounds in the absence of BAX and BAK1. Therefore at concentrations that are on target and achievable in vivo, BH3 mimetics only induce autophagy in a BAX- and BAK1-dependent manner.
| S-EPMC4990995 | biostudies-literature
Project description:BH3-mimetic drugs are an anti-cancer therapy that can induce apoptosis in malignant cells by directly binding and inhibiting pro-survival proteins of the BCL-2 family. The BH3-mimetic drug venetoclax, which targets BCL-2, has been approved for the treatment of chronic lymphocytic leukaemia and acute myeloid leukaemia by regulatory authorities worldwide. However, while most patients initially respond well, resistance and relapse while on this drug is an emerging and critical issue in the clinic. Though some studies have begun uncovering the factors involved in resistance to BCL-2-targeting BH3-mimetic drugs, little focus has been applied to pre-emptively tackle resistance for the next generation of BH3-mimetic drugs targeting MCL-1, which are now in clinical trials for diverse blood cancers. Therefore, using pre-clinical mouse and human models of aggressive lymphoma, we sought to predict factors likely to contribute to the development of resistance in patients receiving MCL-1-targeting BH3-mimetic drugs. First, we performed multiple whole genome CRISPR/Cas9 KO screens and identified that loss of the pro-apoptotic effector protein BAX, but not its close relative BAK, could confer resistance to MCL-1-targeting BH3-mimetic drugs in both short-term and long-term treatment regimens, even in lymphoma cells lacking the tumour suppressor TRP53. Furthermore, we found that mouse Eµ-Myc lymphoma cells selected for loss of BAX, as well as upregulation of the untargeted pro-survival BCL-2 family proteins BCL-XL and A1, when made naturally resistant to MCL-1 inhibitors by culturing them in increasing doses of drug over time, a situation mimicking the clinical application of these drugs. Finally, we identified therapeutic approaches which could overcome these two methods of resistance: the use of chemotherapeutic drugs or combined BH3-mimetic treatment, respectively. Collectively, these results uncover some key factors likely to cause resistance to MCL-1 inhibition in the clinic and suggest rational therapeutic strategies to overcome resistance that should be investigated further.
| S-EPMC10070326 | biostudies-literature
Project description:Hematologic malignancies (HM) comprise diverse cancers of lymphoid and myeloid origin, including lymphomas (approx. 40%), chronic lymphocytic leukemia (CLL, approx. 15%), multiple myeloma (MM, approx. 15%), acute myeloid leukemia (AML, approx. 10%), and many other diseases. Despite considerable improvement in treatment options and survival parameters in the new millennium, many patients with HM still develop chemotherapy‑refractory diseases and require re-treatment. Because frontline therapies for the majority of HM (except for CLL) are still largely based on classical cytostatics, the relapses are often associated with defects in DNA damage response (DDR) pathways and anti-apoptotic blocks exemplified, respectively, by mutations or deletion of the TP53 tumor suppressor, and overexpression of anti-apoptotic proteins of the B-cell lymphoma 2 (BCL2) family. BCL2 homology 3 (BH3) mimetics represent a novel class of pro-apoptotic anti-cancer agents with a unique mode of action-direct targeting of mitochondria independently of TP53 gene aberrations. Consequently, BH3 mimetics can effectively eliminate even non-dividing malignant cells with adverse molecular cytogenetic alterations. Venetoclax, the nanomolar inhibitor of BCL2 anti-apoptotic protein has been approved for the therapy of CLL and AML. Numerous venetoclax-based combinatorial treatment regimens, next-generation BCL2 inhibitors, and myeloid cell leukemia 1 (MCL1) protein inhibitors, which are another class of BH3 mimetics with promising preclinical results, are currently being tested in several clinical trials in patients with diverse HM. These pivotal trials will soon answer critical questions and concerns about these innovative agents regarding not only their anti-tumor efficacy but also potential side effects, recommended dosages, and the optimal length of therapy as well as identification of reliable biomarkers of sensitivity or resistance. Effective harnessing of the full therapeutic potential of BH3 mimetics is a critical mission as it may directly translate into better management of the aggressive forms of HM and could lead to significantly improved survival parameters and quality of life in patients with urgent medical needs.
| S-EPMC8466478 | biostudies-literature
Project description:TP53 wild-type breast tumors rarely undergo a complete pathological response after chemotherapy treatment. These patients have an extremely poor survival rate and studies show these tumors preferentially undergo senescence instead of apoptosis. These senescent cells persist after chemotherapy and secrete cytokines and chemokines comprising the senescence associated secretory phenotype, which promotes survival, proliferation, and metastasis. We hypothesized that eliminating senescent tumor cells would improve chemotherapy response and extend survival. Previous studies have shown "senolytic" agents selectively kill senescent normal cells, but their efficacy in killing chemotherapy-induced senescent cancer cells is unknown. We show that ABT-263, a BH3 mimetic that targets antiapoptotic proteins BCL2/BCL-XL/BCL-W, had no effect on proliferating cells, but rapidly and selectively induced apoptosis in a subset of chemotherapy-treated cancer cells, though sensitivity required days to develop. Low NOXA expression conferred resistance to ABT-263 in some cells, necessitating additional MCL1 inhibition. Gene editing confirmed breast cancer cells relied on BCL-XL or BCL-XL/MCL1 for survival in senescence. In a mouse model of breast cancer, ABT-263 treatment following chemotherapy led to apoptosis, greater tumor regression, and longer survival. Our results reveal cancer cells that have survived chemotherapy by entering senescence can be eliminated using BH3 mimetic drugs that target BCL-XL or BCL-XL/MCL1. These drugs could help minimize residual disease and extend survival in breast cancer patients that otherwise have a poor prognosis and are most in need of improved therapies.
| S-EPMC7560696 | biostudies-literature