CS2164 combined with radiation suppressed tumor growth via γ-H2AX persistence and ROS accumulation

Abstract Background CS2164 is an oral multi-target inhibitor that targets angiogenesis-related kinases, mitosis-related kinases, and chronic inflammation-related kinases. However, the added clinical benefit of CS2164 combined with radiation remains unknown. Methods The anti-tumor effect of CS2164 combined with radiation were evaluated by CCK-8, colony formation assays and xenograft radiation models (n = 5/per group), based on the hepatocellular carcinoma cells (Huh-7) and cervical cancer cells (HeLa). Meanwhile, the γ-H2AX expression, cell cycle distribution, reactive oxygen species (ROS) assay and transcriptome sequencing analysis of xenografts were performed selected to clarify the mechanism. Results CS2164 combined with radiation effectively decreased growth of the above tumor cells, compared with CS2164 or radiation alone. The sensitivity enhancement ratio (SER, SER=D0(control group) / D0(treated group)) of CS2164 was 1.406 in HeLa cells and 1.123 in Huh-7 cells, respectively. Similar antitumor effects were observed in xenograft radiation models. The results of GO, KEGG pathway and PPI analysis screened out a series of genes that related to DNA damage repair process, oxidation-reduction reaction, and multiple cell death types. Therefore, γ-H2AX expression, cell cycle distribution and ROS assay were detected. There was no significant difference in the number of γ-H2AX foci between control and CS2164-treated cells. While the numbers of γ-H2AX foci increased in the CS2164-treated (3µM) cells after radiation (4 Gy) at 3 and 6 h, compared to cells treated with radiation alone (p < 0.05). Meanwhile, more cells were observed to be blocked in G2/M phase after treatment of CS2164 combined with radiation, compared with CS2164 or radiation alone. Moreover, the ROS level increased after treatment of CS2164 combined with radiation, which could be partially rescued by oxidation scavenger, NAC. Conclusion Our study demonstrates anti-tumor efficacy of CS2164 combined with radiation in treatment of malignant tumors.