Abstract: Background and purpose: Rho GTPase activating protein 4 (ARHGAP4) is closely related to tumor progression, and has important regulatory effects on tumor cell malignant proliferation. This study aimed to investigate the expression of ARHGAP4 in hepatocellular carcinoma and its effect on the growth of hepatocellular carcinoma cells. Methods: The expression of ARHGAP4 in hepatocellular carcinoma tissues was analyzed by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR), Western blot and immunohistochemistry. The relationship between the expression of ARHGAP4 and clinicopathological characteristics and prognosis of hepatocellular carcinoma was analyzed. Then, the expression of ARHGAP4 was silenced. Cell counting kit-8 (CCK-8) and EdU experiments were used to observe the proliferation of hepatocellular carcinoma cells, and the expression level of hexokinase 2 (HK2) in hepatocellular carcinoma cells was detected. The expression of HK2 in hepatocellular carcinoma tissues and its correlation with ARHGAP4 were further analyzed. Finally, HK2 expression was up-regulated in hepatocellular carcinoma cells stably expressing low levels of ARHGAP4, while HK2 expression was silenced in hepatocellular carcinoma cells stably expressing high levels of ARHGAP4. Western blot was used to analyze the expression of HK2, and EdU was used to analyze the proliferation of hepatocellular carcinoma cells. Results: The expression levels of ARHGAP4 mRNA and protein in hepatocellular carcinoma tissues were significantly higher compared with adjacent tissues (P<0.01), and the high expression of ARHGAP4 was closely related to the tumor size and TNM stage of patients. Silencing the expression of ARHGAP4 significantly reduced the proliferative ability and HK2 expression level in hepatocellular carcinoma cells (P<0.05). Conversely, overexpression of ARHGAP4 significantly enhanced HK2 expression and cell proliferative ability (P<0.05), and expressions of ARHGAP4 and HK2 in hepatocellular carcinoma were positively correlated. Mechanistically, ARHGAP4 positively regulated the expression of HK2 to affect the growth of hepatocellular carcinoma. Conclusion: ARHGAP4 promotes the growth of hepatocellular carcinoma cells by positively regulating the expression of HK2.

Key words: Rho GTPase activating protein 4, Hexokinase 2, Hepatocellular carcinoma, Proliferation, Apoptosis