Differential regulation of protein kinase C isoforms in human uterine leiomyoma

The protein kinase C (PKC) isoenzyme expression pattern in human uterine leiomyoma was compared with that obtained in homologous myometrium distal from the tumor. The six PKC isoforms (PKCalpha, PKCbeta1, PKCbeta2, PKCdelta, PKCepsilon and PKCzeta) evidenced in the myometrium were found to be similarly expressed in leiomyoma. Quantitative immunoblotting revealed that all PKC isoforms were preferentially localized in the particulate fraction. To gain insight into the possible functional consequences of PKC expression patterns, subcellular redistribution in response to the mitogenic peptide endothelin-1 (ET-1) was studied. After stimulation with ET-1, differential redistribution occurred in leiomyoma and myometrium, suggesting a selective role of PKC isoforms in the myometrial growth process.