Expression patterns of ornithine decarboxylase and c-met in growing Yoshida AH-130 hepatoma.

The expression of the two proto-oncogenes ornithine decarboxylase and c-met was examined during various phases of growth of Yoshida AH-130 ascites hepatoma. Ornithine decarboxylase (ODC) and c-met mRNA levels declined progressively from day 5 (exponential growth-phase) until day 14 (quasi-stationary growth-phase). Transcription rate for both the genes remained constant between days 5 and 10, while decreasing at day 14. ODC activity was consistent with ODC mRNA level during hepatoma growth. In host liver, ODC mRNA accumulated 5 and 14 days after tumor transplantation, while c-met mRNA level was elevated until day 10 and diminished at day 14. ODC activity triplicated at day 14 in host liver. The progressive decline in the expression of ODC and c-met observed in hepatoma might be one of the mechanisms important for the control of tumor growth.