PERITONEAL-FLUID FROM OVARIAN-CANCER PATIENTS STIMULATES MUC1 EPITHELIAL MUCIN EXPRESSION IN OVARIAN-CANCER CELL-LINES

The MUCI epithelial mucin is a transmembrane glycoprotein that is freq uently but variably over-expressed by adenocarcinomas. It is used as a diagnostic serum tumour marker and is a candidate target for tumour i mmunotherapy, Peritoneal fluid (PF) samples from ovarian cancer patien ts were investigated for their ability to modulate MUCI expression in 6 ovarian cancer cell lines which showed a range from very low to high endogenous MUCI expression. Cell lines were cultured in 20% PF for 4 days, fixed in site and MUCI assayed by ELISA, MUCI expression was sti mulated by some PF samples in 5 of 6 lines tested. MUCI expression in the PE04 cell line (very low endogenous expression) was increased by 3 5 of 36 PFs tested (p < 0.05); stimulation varied between PFs but was greater than with 100 IU/mL hu-r-gamma-interferon. Western blotting co nfirmed the stimulation of MUCI in PE04 cells and FAGS showed an incre ase in the proportion of cells expressing MUCI. The active factor was partially purified by gel filtration and was shown to stimulate PE04 c ells in a dose-dependent manner. Concentrations of IL1 beta, IL4, IL6, IL8, IL10, TNF-alpha, TGF-beta and GM-CSF were often very high in PF and varied substantially between different PF samples but did not corr elate with the degree of MUCI stimulatory activity. (C) 1998 Wiley-Lis s, Inc.