Rho GTPase Activating Protein 9 (ARHGAP9) in Human Cancers

In recent years, targeted therapy combined with traditional chemoradiotherapy and surgery has brought new opportunities for cancer treatment. However, the complex characteristics of cancer, such as heterogeneity and diversity, limit the clinical success of targeted drugs. Discovering of new cancer targets and deepening the understanding of their functional mechanisms will bring additional promising application prospects for the research and development of personalized cancer-targeted drugs. This study aimed to summarize the role of the Rho GTPase activating protein 9 (ARHGAP9) gene in tumorigenesis and development to discover therapeutic targets for cancer in the future. For this review, we collected patents from the databases of Espacenet and WIPO and articles from PubMed that were related to the ARHGAP9 gene. Genetic/epigenetic variations and abnormal expression of the ARHGAP9 gene are closely associated with a variety of diseases, including cancer. ARHGAP9 can inactivate Rho GTPases by hydrolyzing GTP into GDP and regulate cancer cellular events, including proliferation, differentiation, apoptosis, migration and invasion, by inhibiting JNK/ERK/p38 and PI3K/AKT signaling pathways. In addition to reviewing these mechanisms, we assessed various patents on ARHGAP9 to determine whether ARHGAP9 might be used as a predictive biomarker for diagnosis/prognosis evaluation and a druggable target for cancer treatment. In this review, the current knowledge of ARHGAP9 in cancer is summarized with an emphasis on its molecular function, regulatory mechanism and disease implications. Its characterization is crucial to understanding its important roles during different stages of cancer progression and therapy as a predictive biomarker and/or target.