2. Academic Validation
  3. Loss of fragile WWOX gene leads to senescence escape and genome instability

Loss of fragile WWOX gene leads to senescence escape and genome instability

  • Cell Mol Life Sci. 2023 Oct 28;80(11):338. doi: 10.1007/s00018-023-04950-1.
Hui-Ching Cheng 1,  Po-Hsien Huang # 2,  Feng-Jie Lai # 3 4,  Ming-Shiou Jan # 5,  Yi-Lin Chen 6 7,  Szu-Ying Chen 2,  Wan-Li Chen 7,  Chao-Kai Hsu 8,  Wenya Huang 6,  Li-Jin Hsu 9 10 11 12
Affiliations

Affiliations

  • 1 Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
  • 2 Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
  • 3 Department of Dermatology, Chi Mei Medical Center, Tainan, 71004, Taiwan. [email protected].
  • 4 Center for General Education, Southern Taiwan University of Science and Technology, Tainan, 71005, Taiwan. [email protected].
  • 5 Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, 40201, Taiwan.
  • 6 Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
  • 7 Molecular Diagnosis Laboratory, Department of Pathology, National Cheng Kung University Hospital, Tainan, 704302, Taiwan.
  • 8 Department of Dermatology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
  • 9 Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. [email protected].
  • 10 Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. [email protected].
  • 11 Center of Infectious Disease and Signaling Research, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. [email protected].
  • 12 Research Center for Medical Laboratory Biotechnology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. [email protected].
  • # Contributed equally.
PMID: 37897534 DOI: 10.1007/s00018-023-04950-1
Abstract

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 p16Ink4a promoter hypermethylation, aberrant p53/p21Cip1/Waf1 signaling axis and accelerated p27Kip1 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 p21Cip1/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.

Keywords

CDK inhibitors; Mononucleotide repeat markers; Promoter hypermethylation; Redox homeostasis; Replicative arrest; Tumor suppressor.

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