Vitronectin, fibronectin and epidermal growth factor induce proliferation via the JNK and ERK pathways in insulinoma INS-1 cells.

Abstract

An insulinoma is a tumor formed by beta cells in the Langerhans islets of the pancreas. Vitronectin (VTN), fibronectin (FN) and epidermal growth factor (EGF) are important in cell signaling. The aim of this study was to investigate the molecular mechanism that occurs in INS-1 cells with the administration of VTN, FN and EGF in proliferative doses. We determined the proliferative doses of EGF, VTN and FN. The molecular mechanism of proliferation has been investigated alone or in the combination of these proteins. It was observed that INS-1 cells did not have VTN and FN. Cell viability increased with the administration of 0.1g/ml VTN, 0.1g/ml FN and 1mg/ml EGF. Proliferation increased with the administration of FN+EGF, and VTN+FN+EGF together when compared to the control group. The total JNK levels did not change between the groups; however, the active JNK levels increased in the VT+FN+EGF group compared to the control group. The total ERK levels increased in the VT+FN+EGF group, and the active ERK levels increased in the VTN+FN, VTN+EGF and VTN+FN+EGF groups compared to the control group. The JNK and ERK pathways are important for proliferation. The JNK and ERK pathways were activated in VTN+FN+EGF administered group. However, it was observed that the ERK pathway was more active than the JNK pathway.