p21H-ras-induced morphological transformation and increases in c-myc expression are independent of functional protein kinase C.

It has previously been demonstrated that efficient DNA synthesis by oncogenic p21H-ras only occurs in the presence of insulin and is absolutely dependent on functional protein kinase C. Here we show that morphological transformation induced by oncogenic p21H-ras does not require functional protein kinase C. The early phases of protein kinase C-independent morphological transformation do not require de novo protein synthesis. We have also demonstrated that the introduction of p21H-ras into quiescent Swiss 3T3 cells by scrape-loading leads to increased levels of c-myc mRNA similar to those seen following serum stimulation. The increases in c-myc mRNA levels induced by p21H-ras are also independent of functional protein kinase C. Both morphological transformation and the elevation of c-myc mRNA levels do not require insulin. These results demonstrate that p21H-ras is generating protein kinase C-dependent and -independent signals.