Loss of fragile WWOX gene leads to senescence escape and genome instability.
Hui-Ching ChengPo-Hsien HuangFeng-Jie LaiMing-Shiou JanYi-Lin ChenSzu-Ying ChenWan-Li ChenChao-Kai HsuWenya HuangLi-Jin HsuPublished in: Cellular and molecular life sciences : CMLS (2023)
Induction of DNA damage response (DDR) to ensure accurate duplication of genetic information is crucial for maintaining genome integrity during DNA replication. Cellular senescence is a DDR mechanism that prevents the proliferation of cells with damaged DNA to avoid mitotic anomalies and inheritance of the damage over cell generations. Human WWOX gene resides within a common fragile site FRA16D that is preferentially prone to form breaks on metaphase chromosome upon replication stress. We report here that primary Wwox knockout (Wwox -/- ) mouse embryonic fibroblasts (MEFs) and WWOX-knockdown human dermal fibroblasts failed to undergo replication-induced cellular senescence after multiple passages in vitro. Strikingly, by greater than 20 passages, accelerated cell cycle progression and increased apoptosis occurred in these late-passage Wwox -/- MEFs. These cells exhibited γH2AX upregulation and microsatellite instability, indicating massive accumulation of nuclear DNA lesions. Ultraviolet radiation-induced premature senescence was also blocked by WWOX knockdown in human HEK293T cells. Mechanistically, overproduction of cytosolic reactive oxygen species caused p16 Ink4a promoter hypermethylation, aberrant p53/p21 Cip1/Waf1 signaling axis and accelerated p27 Kip1 protein degradation, thereby leading to the failure of senescence induction in Wwox-deficient cells after serial passage in culture. We determined that significantly reduced protein stability or loss-of-function A135P/V213G mutations in the DNA-binding domain of p53 caused defective induction of p21 Cip1/Waf1 in late-passage Wwox -/- MEFs. Treatment of N-acetyl-L-cysteine prevented downregulation of cyclin-dependent kinase inhibitors and induced senescence in Wwox -/- MEFs. Our findings support an important role for fragile WWOX gene in inducing cellular senescence for maintaining genome integrity during DDR through alleviating oxidative stress.
Keyphrases
- endothelial cells
- high glucose
- cell cycle arrest
- cell cycle
- induced apoptosis
- dna damage
- oxidative stress
- genome wide
- stress induced
- radiation induced
- cell proliferation
- copy number
- signaling pathway
- cell death
- endoplasmic reticulum stress
- diabetic rats
- dna binding
- dna damage response
- reactive oxygen species
- dna methylation
- gene expression
- stem cells
- mitochondrial dna
- dna repair
- single molecule
- pi k akt
- radiation therapy
- transcription factor
- extracellular matrix
- pluripotent stem cells
- genome wide identification
- drug induced
- cell free
- health information
- circulating tumor
- circulating tumor cells
- nucleic acid