Involvement of Ca²⁺ in platelet-derived growth factor-induced expression of c-myc oncogene in Swiss 3T3 fibroblasts

Addition of platelet-derived growth factor (PDGF) to quiescent cultures of Swiss 3T3 fibroblasts rapidly increased the cytoplasmic free Ca²⁺ concentrations and afterwards the c-myc mRNA levels. The concentrations of PDGF needed for both reactions were roughly the same. Moreover, the Ca²⁺ ionophores, A23187 and ionomycin, mimicked the actions of PDGF and increased the c-myc mRNA levels. These results suggest that Ca²⁺ may be involved in the regulation of PDGF-induced expression of the c-myc gene.