Abstract
Kinesin family member 4A (KIF4A) is located in the human chromosome band Xq13.1. It has a highly conserved kinesin motor region at its N-terminus, which is followed by a central coiled-coil region and a C-terminus cargo-binding domain that contains a cysteine-rich motif. It is aberrantly expressed in a variety of cancers. Our study aimed to determine the expression of KIF4A in renal cell carcinoma (RCC) and to gain new insights into the underlying molecular mechanisms of this disease. Here, we found that KIF4A expression in RCC specimens increased relative to that in normal renal tissues. A significant correlation existed between the expression of KIF4A and the clinicopathologic features of RCC. Elevated KIF4A expression was associated with poor overall survival and disease-free survival. Univariate and multivariate Cox regression analysis revealed that KIF4A was an independent prognostic factor for poor survival in human patients with RCC. CCK-8 proliferation assay, cell cycle analysis, and subcutaneous tumor formation analysis in nude mice consistently showed that KIF4A promoted RCC proliferation. Our findings also indicated that KIF4A functions as an accelerator of RCC metastasis as certified through transwell chamber analysis, wound healing assay, and angiogenesis assay. The expression levels of cyclin D1, cyclin E2, matrix metalloproteinase-2, matrix metalloproteinase-9, hypoxia-inducible factor 1α, and vascular endothelial growth factor in the KIF4A knockdown group were lower than those in the control group and were consistent with those in classic oncogenic pathways. These findings implied that the expression of KIF4A was significantly related to the tumor incidence, metastasis, and prognosis of patients with RCC. Our work provides new breakthroughs for the diagnosis and treatment of RCC.