Effect of TIS21 on DNA Damage Repair Induced by Etoposide

TIS21/BTG2/PC3 (12-O-tetradecanoyl phorbol-13-acetate-inducible sequence 21) has been known as a p53 target gene and functions as a tumor suppressor in carcinogenesis of thymus, prostate, kidney, and liver. Although it has been known that the expression of TIS21/BTG2/PC3 was induced during chemotherapy-mediated DNA damage in cancer cells, a role of TIS21/BTG2/PC3 in DNA repair process remains to be elucidated. In this study, the mechanism and role of TIS21 involved in eotposide induced DNA damage signaling were examined. H2AX foci formation, representative marker for DNA damage, was increased in TIS21-/- mouse embryo fibroblasts (MEFs) compared to wild type MEFs. Foci formation of H2AX after etoposide treatment in LacZ infected Huh7 cells were more retained than TIS21 infected Huh7 cells. Comet assay also showed that DNA damage induced by etoposide were smaller in TIS21 expressed cells. In order to examine TIS21 involved in DNA damage repair and apoptosis, immunoblot analysis was performed. The phosphorylation level of Chk2T68 and p53S20 in the present of etoposide in TIS21 infected Huh7 cells (harboring mutant p53) was significantly decreased as compared to LacZ infected cells. In addition to wild type p53 harboring cells such as MCF7, HeLa, and H9C2 cell lines were also confirmed, and it showed same phenomenon with Huh7 cells. Bcl-2-associated X protein (BAX) and p53 upregulated modulator of apoptosis(PUMA), which are known to be pro-apoptotic proteins in p53-dependent apoptosis, were not induced in TIS21 infected Huh7 cells. Caspase 3/7 activity, chromatin condentation and annexin V staining data suggest that TIS21 inhibited Chk2-p53 DNA damage pathway. Furthermore, TIS21 regulated PRMT1 activity and induced hypermethylation of Mre11 protein. In conclusion, TIS21 involved DNA damage signaling and inhibited Chk2-p53 pathway via Mre11 methylation.

Author dc:creator

• 최, 규성

Contributors dc:contributor

• 박, 태준
• 대학원 의생명과학과
• 200824574

• ATM
• Chk2
• BTG2
• TIS21
• DNA damage
• Apoptosis
• Mre11

Language dc:language

en

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000010954
000000010954

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/2248