The significance of Ras guanine nucleotide exchange factor, son of sevenless protein, in renal cell carcinoma cell lines.

Abstract

The aim of the present study is to clarify the significance of the Ras guanine-nucleotide exchange reaction in the proliferation of human renal cell carcinoma cell lines. We examined the expression of human son of sevenless-1 (hSos-1) protein and the epidermal growth factor (EGF) receptor in human renal cell carcinoma cell lines by Western blot analysis. Additionally, a dominant negative H-ras mutant, N116Y, which is known to inhibit the Ras guanine-nucleotide exchange reaction, was transfected into these cell lines by lipofection. Human renal cell carcinoma cell lines expressed much higher amounts of the EGF receptor and hSos-1 protein than normal kidney tissue. Moreover, the N116Y ras mutant could strongly suppress cellular proliferation in these cell lines. Augmentation of the Ras guanine-nucleotide exchange reaction might be essential to the proliferation of human renal cell carcinoma cells.