lncRNA PVT1 Promotes Tumorigenesis of Colorectal Cancer by Stabilizing miR-16-5p and Interacting with the VEGFA/VEGFR1/AKT Axis.

Recently, the long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) was reported to be involved in the pathogenesis of several cancers, including human colorectal cancer (CRC). However, the molecular basis for cancer initiation, development, and progression remains unclear. In this study, we observe that upregulated PVT1 is associated with poor prognosis and bad clinicopathological features of CRC patients. In vitro means of PVT1 loss in a CRC cell line inhibit cell proliferation, migration, and invasion. Furthermore, dual-luciferase reporter and RNA pull-down assays indicated that PVT1 binds to miR-16-5p, which has been shown to play strong tumor suppressive roles in CRC. Targeted loss of miR-16-5p partially rescues the suppressive effect induced by PVT1 knockdown. Vascular endothelial growth factor A (VEGFA), a direct downstream target of miR-16-5p, was suppressed by PVT1 knockdown in CRC cells. Overexpression of VEGFA is known to modulate the AKT signaling cascade by activating vascular endothelial growth factor receptor 1 (VEGFR1). We, therefore, show that PVT1 loss combined with miR-16-5p overexpression reduces tumor volume maximally when propagated within a mouse xenograft model. We conclude that the PVT1-miR-16-5p/VEGFA/VEGFR1/AKT axis directly coordinates the response in CRC pathogenesis and suggest PVT1 as a novel target for potential CRC therapy.