Semiquantitative PCR of alpha2 and alpha4 integrin mRNA shows differential response to the transcriptional modulators TGF-beta1 and TPA.

The differential expression of VLA integrins in different cell types under different conditions has been mainly studied at the protein level. Since these cell surface proteins have a rather slow turn-over, quantitative changes in their transcription may go unnoticed. The expression of alpha2 and alpha4 mRNA was studied by relative quantitative RT-PCR on Molt-4 (human T-cell lymphoma) and A875 (human melanoma) cells. Modulation of the expression was investigated by treatment with TGF-beta1 and TPA. Stimulation with TGF-beta1 increased the expression of alpha4 in Molt-4 cells and of alpha2 in A875 cells. Treatment with TPA did not alter the expression of alpha4 mRNA on Molt-4 cells but significantly increased their alpha2 expression. Thus, integrin expression can be modulated differentially and this modulation can be reinforced by transcriptional activators.