SOX4-induced upregulation of ARHGAP9 promotes the progression of acute myeloid leukemia.

Abstract

Acute myeloid leukemia (AML) is the most common acute leukemia. Rho GTPase activating protein 9 (ARHGAP9) has been reported to be positively correlated with overall survival of AML patients, but the specific molecular function remains unclear. This study aims to further explore the functional role and the molecular mechanism of ARHGAP9 in AML cells. The expression level of ARHGAP9 in AML cells was measured using quantitative real-time PCR (qRT-PCR) and western blot. Cell transfection was performed to interfere ARHGAP9. CCK-8, flow cytometry and TUNEL assays were conducted to detect cell viability, cell cycle distribution and apoptosis, respectively. The binding relationship between SOX4 and ARHGAP9 promoter was verified using luciferase reporter assay and chromatin immunoprecipitation. The results showed that ARHGAP9 was upregulated in AML cells. Interference of ARHGAP9 greatly reduced cell viability and induced cell cycle arrest in G1 phase, accompanied with the reduction of Ki67, PCNA, cyclin D1, cyclin E1, CDK4 and CDK6. In addition, Interference of ARHGAP9 greatly promoted cell apoptosis, accompanied with the decreased protein expression of Bcl-2 and the increased protein expression of Bax, cleaved caspase 3 and cleaved caspase 9. Furthermore, SOX4 directly bound to ARHGAP9 promoter and regulated ARHGAP9 expression. In conclusion, this study suggested that ARHGAP9 interference exerted an anti-tumor effect through inhibiting cell proliferation, blocking cell cycle progression, and promoting cell apoptosis in AML cells. ARHGAP9 may serve as a novel therapeutic target for AML.