Drug Design, Development and Therapy (Nov 2019)
Identification Of Natural Compound Derivative For Inhibition Of XLF And Overcoming Chemoresistance In Colorectal Cancer Cells
Abstract
Zhuo Liu,1 Miao Yu,1 Bingyuan Fei,1 Jing Sun,2 Dongxin Wang3 1Department of Gastrointestinal Colorectal and Anal Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin, People’s Republic of China; 2Department of Biochemistry and Molecular Medicine, The George Washington University, Washington, DC, USA; 3Department of Anesthesiology, Jilin Cancer Hospital, Jilin, People’s Republic of ChinaCorrespondence: Dongxin WangDepartment of Anesthesiology, Jilin Cancer Hospital, 1018 Huguang Road, Changchun, Jilin 130031, People’s Republic of ChinaTel +86 139 4487 2227Email [email protected]: A previous study has identified that XRCC4-like factor (XLF) is a potential target to overcome resistance to 5-fluorouracil (5-Fu) and oxaliplatin (OXA) in colorectal cancer (CRC). The purpose of this study is to develop potent XLF inhibitors to chemoresistance in CRC.Methods: Virtual screening was adopted to identify novel XLF-binding compounds by initially testing 6800 molecules in Chemical Entities of Biological Interest library. Hit compounds were further validated by Western blot assay. Cell sensitivity to 5-Fu and OXA was measured using sulforhodamine B assay. The effect of XLF inhibitor on DNA repair efficiency was evaluated by comet assay, fluorescent-based nonhomologous end joining (NHEJ) and homologous recombination (HR) reporter assays. DNA-binding activity of NHEJ key factors was examined by chromatin fractionation assay.Results: We identified G3, a novel and potent XLF inhibitor (IC50 0.47±0.02 μM). G3 induced XLF protein degradation in CRC cells. Significantly, G3 improved cell sensitivity to 5-Fu and OXA in chemoresistant CRC cell lines. Mechanistically, G3 depleted XLF expression, severely compromised NHEJ efficiency by up to 65% and inhibited NHEJ key factor assembly on DNA. G3 also inhibited HR efficiency in a time-dependent manner.Conclusion: These results suggest that G3 overcomes 5-Fu and OXA resistance in CRC cells by inhibiting XLF expression. Thus, XLF is a promising target and its inhibitor G3 is a potential candidate for treatment of chemoresistant CRC patients.Keywords: virtual screening, XLF inhibitor, chemoresistance, colorectal cancer
