Methylation of FAM110C is a synthetic lethal marker for ATR/CHK1 inhibitors in pancreatic cancer

J Transl Int Med. 2024 Jul 27;12(3):274-287. doi: 10.2478/jtim-2023-0128. eCollection 2024 Jun.

Abstract

Background and objectives: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies. An epigenetic-based synthetic lethal strategy provides a novel opportunity for PDAC treatment. Finding more DNA damage repair (DDR)-related or cell fate-related molecules with aberrant epigenetic changes is becoming very important. Family with sequence similarity 110C (FAM110C) is a cell fate-related gene and its function in cancer remains unclear.

Methods: Seven cell lines, 34 cases of intraductal papillary mucinous neoplasm (IPMN), 15 cases of mucinous cystic neoplasm (MCN) and 284 cases of PDAC samples were employed. Methylation-specific PCR, western blot, CRISPR knockout, immunoprecipitation and a xenograft mouse model were used in this study.

Results: FAM110C is methylated in 41.18% (14/34) of IPMN, 46.67% (7/15) of MCN and 72.89% (207/284) of PDAC, with a progression trend from IPMN/MCN to pancreatic cancer (P = 0.0001, P = 0.0389). FAM110C methylation is significantly associated with poor overall survival (OS) (P = 0.0065) and is an independent prognostic marker for poor OS (P = 0.0159). FAM110C inhibits PDAC cells growth both in vitro and in vivo, serving as a novel tumor suppressor. FAM110C activates ATM and NHEJ signaling pathways by interacting with HMGB1. Loss of FAM110C expression sensitizes PDAC cells to VE-822 (an ATR inhibitor) and MK-8776 (a CHK1 inhibitor).

Conclusion: FAM110C methylation is a potential diagnostic and prognostic marker in PDAC, and its epigenetic silencing sensitizes PDAC cells to ATR/CHK1 inhibitors.

Keywords: DNA damage repair; DNA methylation; FAM110C; pancreatic cancer; synthetic lethality.

Grants and funding

This work was supported by grants from National Key Research and Development Program of China (2018YFA0208902, 2020YFC2002705); National Science Foundation of China (NSFC No. 82272632, 81672138).