BCL-2 pathway counteracts aneuploidy in mammalian embryos
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ABSTRACT:
PROVIDER: PRJEB36524 | ENA |
REPOSITORIES: ENA
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Project description:DNA double-strand breaks (DSBs) are toxic to mammalian cells. However, during meiosis, more than 200 DSBs are generated deliberately, to ensure reciprocal recombination and orderly segregation of homologous chromosomes. If left unrepaired, meiotic DSBs can cause aneuploidy in gametes and compromise viability in offspring. Oocytes in which DSBs persist are therefore eliminated by the DNA-damage checkpoint. The checkpoint’s downstream effectors that trigger oocyte death, thereby preserving genome stability across the generations, are unknown. Here we show that the DNA-damage checkpoint eliminates oocytes via the pro-apoptotic BCL-2 pathway members Puma, Noxa and Bax. Deletion of these factors prevents oocyte elimination in recombination-repair mutants, even when the abundance of unresolved DSBs is high. Remarkably, surviving oocytes can extrude a polar body and be fertilised, despite chaotic chromosome segregation at the first meiotic division. Our findings raise the possibility that allelic variants of the BCL-2 pathway could influence the risk of embryonic aneuploidy.
2020-03-26 | E-MTAB-8752 | biostudies-arrayexpress
Project description:Genome-wide genetic screens have identified cellular dependencies in many cancers. Using Novartis’ DRIVE and the Broad Institute’s Achilles shRNA screening datasets, we mined for targetable dependencies in kidney lineage cancer cells. Our studies identified a dependency, preferentially in kidney cancer cells versus cells of other lineages, on the BCL2L1 gene, which encodes the Bcl-xL anti-apoptotic protein. Genetic and pharmacological inactivation of Bcl-xL, but not its paralog BCL2, led to fitness defects in renal cancer cells, and also sensitized them to chemotherapeutics. Expression levels of Bcl-xL, VHL status, and p53 mutation status were insufficient to predict Bcl-xL dependence. Instead, analyzing the transcriptional hallmarks of response to Bcl-xL blockade identified an elevated mesenchymal cell state signature in Bcl-xL dependent lines. Functional studies to address if these cell state differences drive Bcl-xL dependence showed that maintaining mesenchymal characteristics was necessary to confer sensitivity to Bcl-xL loss; and, conversely, that promoting mesenchymal transition was sufficient to increase sensitivity to Bcl-xL inhibition in resistant cells. This mesenchymal signature was also observed in almost a third of human renal tumors, and is associated with worse clinical outcomes. Detachment from an organized epithelium incites protective apoptotic responses in normal cells (e.g. anoikis); however, our findings suggest that, in mesenchymal kidney cancer cells Bcl-xL activity counteracts this protective mechanism and enables tumor cell survival. Altogether, our studies uncover an unexpected link between cellular cell state and dependence on anti-apoptotic proteins, and justify the use of Bcl-xL blockade to target a clinically aggressive subset of human kidney cancers.
2022-06-15 | GSE173618 | GEO
Project description:Preimplantation genetic diagnosis (PGD) of aneuploidy by fluorescence in situ hybridisation (FISH) has not delivered the expected clinical benefit. Many previous re-analysis studies of embryos deemed aneuploid by FISH on day 3 have found a high degree of chromosomal normalcy at the blastocyst stage. While most have interpreted this as “self correction,” there remains a lack of evidence for such a phenomenon. A more comprehensive technique for 24 chromosome aneuploidy screening was utilised here to re-evaluate blastocysts previously diagnosed as abnormal by FISH and investigate possible self correction mechanisms, including extrusion or duplication of aneuploid chromosomes resulting in uniparental isodisomy (UPID), and preferential segregation of aneuploidy to the trophectoderm (TE). Embryos that developed to a morphologically normal blastocyst after an aneuploidy diagnosis by cleavage stage FISH were biopsed into 4 sections, 3 TE and 1 inner cell mass (ICM), and randomised for evaluation by single nucleotide polymorphism (SNP) microarray based 24 chromosome aneuploidy screening (MA-PGD). Fifty-eight percent of blastocysts were euploid for all 24 chromosomes despite an aneuploid FISH result on day 3. Only 18% were consistent with the original FISH diagnosis, while the remaining 24% identified abnormalities that were different from the original FISH diagnosis. Abnormalities did not preferentially segregate to the TE and aneuploid chromosome extrusion or duplication resulting in UPID did not occur. Cleavage stage FISH is poorly predictive of aneuploidy in an embryo that develops into a morphologically normal blastocyst. Clinicians should consider re-evaluating embryos diagnosed as aneuploid by FISH that form morphologically normal blastocysts using a validated comprehensive 24 chromosome aneuploidy screening method.
2010-05-19 | GSE18932 | GEO
Project description:Aneuploidy promotes genomic instability by impairing DNA replication
| PRJEB7596 | ENA
Project description:Preimplantation genetic diagnosis (PGD) of aneuploidy by fluorescence in situ hybridisation (FISH) has not delivered the expected clinical benefit. Many previous re-analysis studies of embryos deemed aneuploid by FISH on day 3 have found a high degree of chromosomal normalcy at the blastocyst stage. While most have interpreted this as âself correction,â there remains a lack of evidence for such a phenomenon. A more comprehensive technique for 24 chromosome aneuploidy screening was utilised here to re-evaluate blastocysts previously diagnosed as abnormal by FISH and investigate possible self correction mechanisms, including extrusion or duplication of aneuploid chromosomes resulting in uniparental isodisomy (UPID), and preferential segregation of aneuploidy to the trophectoderm (TE). Embryos that developed to a morphologically normal blastocyst after an aneuploidy diagnosis by cleavage stage FISH were biopsed into 4 sections, 3 TE and 1 inner cell mass (ICM), and randomised for evaluation by single nucleotide polymorphism (SNP) microarray based 24 chromosome aneuploidy screening (MA-PGD). Fifty-eight percent of blastocysts were euploid for all 24 chromosomes despite an aneuploid FISH result on day 3. Only 18% were consistent with the original FISH diagnosis, while the remaining 24% identified abnormalities that were different from the original FISH diagnosis. Abnormalities did not preferentially segregate to the TE and aneuploid chromosome extrusion or duplication resulting in UPID did not occur. Cleavage stage FISH is poorly predictive of aneuploidy in an embryo that develops into a morphologically normal blastocyst. Clinicians should consider re-evaluating embryos diagnosed as aneuploid by FISH that form morphologically normal blastocysts using a validated comprehensive 24 chromosome aneuploidy screening method. Affymetrix SNP arrays were processed according to the manufacturer's directions on DNA extracted from 50 cryopreserved blastocysts that were biopsied into 3 sections of trophectoderm and 1 inner cell mass section. Affymetrix SNP array analysis was successfully completed on 145 trophectoderm samples and 47 ICM samples from embryos, 8 lymphocyte samples from cell lines and 6 mixed male and female samples.
2010-05-19 | E-GEOD-18932 | biostudies-arrayexpress
Project description:Overexpression of BCL-xL and BCL-2 play key roles in tumorigenesis and cancer drug resistance. Advances in PROTAC technology facilitated recent development of the first BCL-xL/BCL-2 dual degrader, 753b, a VHL-based degrader with improved potency and reduced toxicity compared to previous small molecule inhibitors. Here, we determined crystal structures of VHL/753b/BCL-xL and VHL/753b/ BCL-2 ternary complexes. The two ternary complexes exhibit markedly different architectures that are accompanied by distinct networks of interactions at the VHL/PZ753b-linker/target interfaces. The importance of these interfacial contacts was validated via functional analysis and informed subsequent rational and structure-guided design focused on the 753b linker and BCL-2/BCL-xL warhead. This resulted in the design of a novel degrader, WH244, with enhanced potency to degrade BCL-xL/BCL-2 in cells. Using biophysical assays followed by in cell activities, we were able to explain the enhanced target degradation of BCL-2/BCL-xL in cells. Most PROTACs are empirically designed and lack structural studies, making it challenging to understand their modes of action and specificity. Our work presents a streamlined approach that combines rational design and structure-based insights backed with cell-based studies to develop effective PROTAC-based cancer therapeutics.
2024-03-12 | PXD049976 | Pride
Project description:The anti-apoptotic function of Bcl-xL in the heart against reperfusion injury is diminished by K-Ras-Mst1-mediated phosphorylation of Ser14, which allows dissociation of Bcl-xL from Bax and promotes cardiomyocyte death. Here we show that Ser14 phosphorylation of Bcl-xL is also promoted by hemodynamic stress in the heart, through the H-Ras-ERK pathway. Our study suggests that phosphorylation of Bcl-xL at Ser14 in response to acute pressure overload plays an essential role in mediating compensatory hypertrophy by promoting calcium release, alleviating the negative constraint of Bcl-xL upon the IP3R-NFAT pathway.
2023-09-06 | PXD045118 | Pride
Project description:Overexpression of BCL-xL and BCL-2 play key roles in tumorigenesis and cancer drug resistance. Advances in PROTAC technology facilitated recent development of the first BCL-xL/BCL-2 dual degrader, 753b, a VHL-based degrader with improved potency and reduced toxicity compared to previous small molecule inhibitors. Here, we determined crystal structures of VHL/753b/BCL-xL and VHL/753b/ BCL-2 ternary complexes. The two ternary complexes exhibit markedly different architectures that are accompanied by distinct networks of interactions at the VHL/PZ753b-linker/target interfaces. The importance of these interfacial contacts was validated via functional analysis and informed subsequent rational and structure-guided design focused on the 753b linker and BCL-2/BCL-xL warhead. This resulted in the design of a novel degrader, WH244, with enhanced potency to degrade BCL-xL/BCL-2 in cells. Using biophysical assays followed by in cell activities, we were able to explain the enhanced target degradation of BCL-2/BCL-xL in cells. Most PROTACs are empirically designed and lack structural studies, making it challenging to understand their modes of action and specificity. Our work presents a streamlined approach that combines rational design and structure-based insights backed with cell-based studies to develop effective PROTAC-based cancer therapeutics.
2024-02-21 | MSV000094144 | MassIVE