ENHANCED EXPRESSION OF THE TYPE-II TRANSFORMING GROWTH-FACTOR-BETA RECEPTOR IN HUMAN PANCREATIC-CANCER CELLS WITHOUT ALTERATION OF TYPE-IIIRECEPTOR EXPRESSION

We have recently found that human pancreatic adenocarcinomas exhibit s trong immunostaining for the three mammalian transforming growth facto r beta (TGF-beta) isoforms. These important growth-regulating polypept ides bind to a number of proteins, including the type I TGF-beta recep tor (TbetaR-I), type II TGF-beta receptor (TbetaR-II), and the type II I TGF-beta receptor (TbetaR-III). In the present study we sought to de termine whether TbetaR-II and TbetaR-III expression is altered in panc reatic cancer. Northern blot analysis indicated that, by comparison wi th the normal pancreas, pancreatic adenocarcinomas exhibited a 4.6-fol d increase (P < 0.01) in mRNA levels encoding TbetaR-II. In contrast, mRNA levels encoding TbetaR-III were not increased. In situ hybridizat ion showed that TbetaR-II mRNA was expressed in the majority of cancer cells, whereas mRNA grains encoding TbetaR-III were detectable in onl y a few cancer cells and were present mainly in the surrounding stroma . These findings suggest that enhanced levels of TbetaR-II may have a role in regulating human pancreatic cancer cell growth, while TbetaR-I II may function in the extracellular matrix.