Acetylation stabilizes chloride intracellular channel 1 that exerts a tumor-promoting role by activation of nuclear factor kappa B in cervical cancer

Abstract

Background: Cervical cancer remains a major cause of cancer-related death in women, especially in developing countries. Previously, we identified that acetylation levels of chloride intracellular channel 1 (CLIC1) at lysine 131 were increased in cervical cancer tissues by using the label-free proteomics approach. The aim of this study was further to determine the role of CLIC1 expression and its acetylation in cervical cancer. Methods: CLIC1 expression and its implications on prognosis in cervical cancer were analyzed using Gene Expression Profiling Interactive Analysis (GEPIA) database (gepia.cancer-pku.cn). The effect of CLIC1 on cells was evaluated by Cell Counting Kit (CCK)-8, flow cytometry, wound healing assay, transwell assay, western blotting, and co-immunoprecipitation (Co-IP). In vivo tumor growth was assessed in mouse xenograft models. Results: We found that CLIC1 expression was increased in cervical cancer tissues and cells. The knockdown of CLIC1 significantly reduced cell proliferation, migration, invasion, and in vivo tumorigenesis of cervical cancer cells. Molecularly, nuclear factor kappa B (NF-κB) activity was positively regulated by CLIC1. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB activation, attenuated the tumor-promoting effect of CLIC1. Moreover, CLIC1 acetylation at K131 was upregulated in cervical cancer, which stabilized CLIC1 by inhibiting ubiquitylation. The substitution of K131 inhibited CLIC1 ubiquitylation and promoted cell proliferation, migration, and invasion, and tumor growth. In addition, we identified that acetyltransferase HAT1 was responsible for CLIC1 acetylation at K131. Conclusion: This finding shows that CLIC1 is a tumor promoter in cervical cancer, indicating a potential strategy to treat cervical cancer by regulating CLIC1 expression or acetylation.