Tumor grade-dependent alterations in the protein kinase C isoform pattern in urinary bladder carcinomas

Objectives: Members of the protein kinase C (PKC) isoenzyme family play central role in the tumorigenesis of several tissues. In this study our goal was to determine the possible alterations in the protein kinase C (PKC) isoform pattern in relation with the different tumor grade in human urinary bladder carcinomas. Methods: Western blot analysis, followed by quantitative densitometry, was performed to define the expression of PKC isoforms in the epithelial tissue of human urinary bladder carcinomas with various tumor grades and in control samples. Results: The human urinary bladder epithelium expressed five PKC isoforms (PKCalpha, beta, delta, epsilon, zeta), the levels of which differentially altered as a function of tumor grade. Namely, whereas the expressions of PKCbeta and delta decreased with increasing grade of the carcinomas, the levels of PKCalpha, epsilon, and zeta showed opposite patterns of changes. Conclusions: These grade-dependent alterations in the PKC isoform pattern strongly argue for the central yet antagonistic roles of certain members of the PKC system in malignant transformation of human urinary bladder epithelium. (C) 2004 Elsevier B.V. All rights reserved.