Measurement of gastrin and transforming growth factor alpha messenger RNA levels in colonic carcinoma cell lines by quantitative polymerase chain reaction.

A synthetic DNA template has been constructed that is suitable for the quantitation of mRNAs encoding gastrin, transforming growth factor alpha (TGF alpha), cholecystokinin, and the 78-kDa gastrin-binding protein. The template was used to measure levels of gastrin and TGF alpha mRNA in 7 colonic and 2 gastric carcinoma cell lines by the polymerase chain reaction. All lines produced detectable gastrin and TGF alpha mRNA with amounts varying between 2.1 and 540 molecules of gastrin mRNA/10(3) cells and 1.1 and 28 molecules of TGF alpha mRNA/10(3) cells. These results are consistent with the hypothesis that both gastrin and TGF alpha act as autocrine growth factors in colon carcinoma cell lines.