Expressional Changes of c-fos, c-jun, and c-myc Induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in HaCaT Cells

Kim, Joo Young

Abstract

Proto-oncogenes (c-fos, c-jun, c-myc) are major nuclear target for signal transduction pathways involved in the regulation of cell growth, differentiation, and transformation. To investigate expressional changes of proto-oncogene induced by 12-O-tetradecanoylphorbol 13-acetate (TPA), the author treated normal human keratinocyte cell line (HaCaT cells) with TPA for 2 hours and 6 hours. To observe changes of the proto-oncogenes at protein and mRNA levels, immunoflourescence staining and northern blot were used, respectively. To assess the distribution of them during the cell cycle, flow cytometric analyses were performed. TPA increased the expression of c-fos and c-jun, while it decreased the expression of c-myc both at protein and mRNA levels in HaCaT cells. The induction of c-Fos in S-G2-M phase appeared within 2 hours. c-Jun was gradually induced during S-G2-M phase. The inhibition of c-Myc was found in G0-G1 phase. These data suggest that aberrations in the proto-oncogenes expression of HaCaT cells exposed to TPA may contribute to the growth, differentiation, and transformation.