Requirement for ras proto-oncogene function during serum-stimulated growth of NIH 3T3 cells

Abstract

Human tumours often contain DNA sequences not found in normal tissues which are able to transform cultured NIH 3T3 cells. In some tumours the gene responsible for this transformation belongs to the cellular ras gene family. A specific type of mutation is responsible for converting the cellular proto-oncogene into a ras oncogene capable of inducing transformation. In a study of the function of a cellular ras gene, its protein product (produced in a bacterial cell) was microinjected into NIH 3T3 cells; the recipient cells became morphologically transformed and were induced to initiate DNA synthesis in the absence of added serum, but only when cellular ras protein was injected at much higher concentrations than required with protein of the transforming ras gene. To further analyse the function of the cellular ras gene, we have now injected monoclonal antibodies against ras proteins into NIH 3T3 cells. We report here that NIH 3T3 cells induced to divide by adding serum to the culture medium are unable to enter the S phase of the cell cycle after microinjection of anti-ras antibody, showing that the protein product of the ras proto-oncogene is required for initiation of the S-phase in NIH 3T3 cells.

Astrocyte elevated gene-1 activates cell survival pathways through PI3K-Akt signaling

“…The effect of AEG-1 expression in THV cells, although less than in PHFA or IM-PHFA, was also significant (Figure 1a, upper panel). Since both SV40 T/t and Haras facilitate serum-independent cell growth (Mulcahy et al, 1985;White et al, 1992;Hahn et al, 2002), THV and THR cells already have the capacity to grow optimally under conditions of serum deprivation (Figure 1a). These results were confirmed and extended using cloned rat embryo fibroblasts (CREF) (Fisher et al, 1982), CREF stably overexpressing Ha-ras (CREF-ras), normal human melanocytes immortalized by SV40 T antigen (FM516) and FM516 cells overexpressing Ha-ras (FM516-ras) (Figures 1b and c).…”

SHP-2 binds to Tyr763 and Tyr1009 in the PDGF β-receptor and mediates PDGF-induced activation of the Ras/MAP kinase pathway and chemotaxis

“…The Ras/MAP kinase pathway has been shown to be crucial for mitogenic signaling of a number of growth factors (Cai et al, 1990;Mulcahy et al, 1985). Thus, we tested whether the Y763F/Y1009F mutation a ected mitogenic signaling.…”

New insights into protein‐tyrosine kinase receptor signaling complexes

“…The most complete description of concerted SH2 and SH3 domain function within cellular signaling pathways has come from studies on a mechanism of activation of the small G-protein Ras. For some time Ras has been known to function downstream of PTKs (Mulcahy et al, 1985;Smith et al, 1986), but the way in which they were linked had proved elusive. However, recently one widely utilized pathway for Ras activation by PTKs has become clear.…”