The putative tumor activator ARHGEF3 promotes nasopharyngeal carcinoma cell pathogenesis by inhibiting cellular apoptosis

Nasopharyngeal carcinoma (NPC) is one of the most prevalent forms of highly invasive malignancy in Southern China and Southeast Asia. The pathogenesis of NPC is a multistep process driven by the acquisition of numerous genetic abnormalities. We investigated the potential oncogenic role of the Rho-guanine nucleotide exchange factor 3 gene, ARHGEF3, in NPC pathogenesis. Expression levels of ARHGEF3 were frequently up-regulated in NPC cell lines and tissues. In a large cohort of clinical NPC tissues high expression of ARHGEF3 was positively associated with an increased T status, distant metastasis, and a more advanced clinical stage (P < 0.05). Survival analysis revealed that ARHGEF3 expression was a significant and independent prognosis factor for NPC patients. In NPC cell lines, knockdown of ARHGEF3 was sufficient to inhibit cell growth, motility, and invasion in vitro, whereas ectopic overexpression of ARHGEF3 substantially enhanced NPC cells tumorigenesis and metastasis in vivo. Depletion of ARHGEF3 in NPC cells dramatically promoted caspase-3 induced apoptosis and an anti-apoptosis factor, BIRC8, was identified as a critical downstream target of the ARHGEF3. Our findings suggest that increased expression of ARHGEF3 plays a critical oncogenic role in NPC pathogenesis by preventing cell apoptosis through the up-regulation of BIRC8, and ARHGEF3 might be employed as a novel prognostic marker and effective therapeutic target for human NPC.