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

ABSTRACT

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: Augmentation of the Ras guanine-nucleotide exchange reaction might be essential to the proliferation of human renal cell carcinoma cells.