Regulation and function of the pro-apoptotic Bcl-2 family member BOK
Cell Biology
Final Report Abstract
Drug-tolerant persister cells (persisters) survive apoptosis upon cancer drug treatments and represent a major non-genetic cause of treatment failure. To explore the mechanisms that mediate persisters overcoming the engagement of mitochondrial cell death, we made use of proapoptotic BH3-mimetics. We show that cells that survive treatment with BH3-mimetics show hallmarks of persisters, including epithelial-to-mesenchymal transition (EMT) and increased sensitivity towards ferroptosis by GPX4 inhibition. By generating MOMP sensor constructs and using CRISPR/Cas9 methodology we show that activation of BCL-2 effector proteins followed by sublethal mitochondrial outer membrane permeabilization (MOMP) and Holocytochrome C release are required for the generation of the persister phenotype. Single cell RNAseq data revealed the activation of the integrated stress response (ISR) in persisters. Further, mechanistical research uncovered that the making of persisters is independent of apoptosome formation and caspase activation, but instead, cytosolic cytochrome C induces the engagement of the ISR with consequent protein translation of ATF4. Our studies show that sublethal cytochrome C release couples sublethal MOMP to caspase-independent initiation of an ATF4-dependent, drug-tolerant persister phenotype.
Publications
- (2019). BRN2 suppresses apoptosis, reprograms DNA damage repair, and is associated with a high somatic mutation burden in melanoma. Gene Dev 33, 310–332
Herbert, K., Binet, R., Lambert, J.-P., Louphrasitthiphol, P., Kalkavan, H., Sesma-Sanz, L., Robles- Espinoza, C., Sarkar, S., Suer, E., Andrews, S., et al.
(See online at https://doi.org/10.1101/gad.314633.118) - (2022): Sublethal Cytochrome-c release generates drug-tolerant persister cells. Cell 185, 3356-3374.e22
H. Kalkavan, M.J. Chen, J.C. Crawford, G. Quarato, P. Fitzgerald, S.W.G. Tait, C.R. Goding, D.R. Green
(See online at https://doi.org/10.1016/j.cell.2022.07.025)
