Int J Biol Sci 2021; 17(9):2167-2180. doi:10.7150/ijbs.58857

Research Paper

Rac GTPase activating protein 1 promotes gallbladder cancer via binding DNA ligase 3 to reduce apoptosis

Rui Bian1,3,4#, Wei Dang2,3,4#, Xiaoling Song2,3,4#, Liguo Liu1,3,4, Chengkai Jiang1,3,4, Yang Yang1,3,4, Yongsheng Li1,3,4, Lin Li1,3,4, Xuechuan Li1,3,4, Yunping Hu2,3,4, Runfa Bao2,3,4✉, Yingbin Liu1,3,4✉

1. Department of Biliary-Pancreatic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
2. Department of General Surgery and Laboratory of General Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200092, China.
3. Shanghai Key Laboratory of Biliary Tract Disease Research, Shanghai 200092, China.
4. State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China.
#These authors contributed equally to this work.

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Citation:
Bian R, Dang W, Song X, Liu L, Jiang C, Yang Y, Li Y, Li L, Li X, Hu Y, Bao R, Liu Y. Rac GTPase activating protein 1 promotes gallbladder cancer via binding DNA ligase 3 to reduce apoptosis. Int J Biol Sci 2021; 17(9):2167-2180. doi:10.7150/ijbs.58857. Available from https://www.ijbs.com/v17p2167.htm

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Abstract

Rac GTPase activating protein 1 (RACGAP1) has been characterized in the pathogenesis and progression of several malignancies, however, little is known regarding its role in the development of gallbladder cancer (GBC). This investigation seeks to describe the role of RACGAP1 and its associated molecular mechanisms in GBC. It was found that RACGAP1 was highly expressed in human GBC tissues, which was associated to poorer overall survival (OS). Gene knockdown of RACGAP1 hindered tumor cell proliferation and survival both in vitro and in vivo. We further identified that RACGAP1 was involved in DNA repair through its binding with DNA ligase 3 (LIG3), a crucial component of the alternative-non-homologous end joining (Alt-NHEJ) pathway. RACGAP1 regulated LIG3 expression independent of RhoA activity. RACGAP1 knockdown resulted in LIG3-dependent repair dysfunction, accumulated DNA damage and Poly(ADP-ribosyl) modification (PARylation) enhancement, leading to increased apoptosis and suppressed cell growth. We conclude that RACGAP1 exerts a tumor-promoting role via binding LIG3 to reduce apoptosis and facilitate cell growth in GBC, pointing to RACGAP1 as a potential therapeutic target for GBC.

Keywords: RACGAP1, LIG3, gallbladder cancer, DNA damage repair, apoptosis