Characteristics and growth patterns of human peritoneal mesothelial cells:Comparison between advanced epithelial ovarian cancer and non-ovarian cancer sources

OBJECTIVE: To compare the characteristics and growth patterns of human peri toneal mesothelial cells (HPMCs) from advanced epithelial ovarian cancer (E OC) patients with those from non-EOC patients. METHODS: Peritoneal and omental biopsies were obtained from treatment-naive patients. Formalin-fixed biopsies and cytologic touch preparations were st udied immunochemically. HPMCs were isolated from tissue biopsies or maligna nt ascites and cultured with or without growth factors. Cell growth was det ermined by the MTT assay. Cultured HPMCs were further characterised by flow cytometry analysis (FACS). RESULTS: Peritoneal biopsies showed a continuous flat mesothelial cell laye r in non-EOC patients, whereas in advanced EOC, the mesothelium was a disco ntinuous layer of rounded cells. In all peritoneal biopsies, the mesotheliu m expressed cytokeratin 8/18, vimentin, and the mesothelioma cell antigen b ut not E-cadherin. In touch preparations, expression of the putative fibrob last antigen ranged from negative to weakly positive. HPMC from non-EOC cas es grew slowly in vitro except when exposed to L-cysteine (L-cys 30 mu g/mL ) during the initial 24 hours of culture. Conversely, cells from EOC source s grew more rapidly, especially when exposed to both epidermal growth facto r (EGF 10 ng/mL) and hydrocortisone (HC 400 ng/mL). HPMC coexpressed cytoke ratin 8/18 and vimentin in vitro, but the expression of the putative fibrob last antigen increased during primary culture, whereas that of the mesothel ioma cell antigen decreased in successive passages. Furthermore, in FACS, c ultured HPMC did not express CD14, CD16, or CD34. CONCLUSION: In peritoneal biopsies from non-EOC and EOC patients, HPMCs sho wed different morphology but similar immunostaining characteristics, wherea s cultured cells from different sources were similar in both morphology and phenotype. L-cysteine enhanced the growth of non-EOC but not of EOC-derive d HPMCs, which had a maximal response to EGF and HC. The growth advantage o f HPMCs from EOC in vitro suggests these cells are in a primed or activated state. (J Soc Gynecol Investig 1999;6:333-40) Copyright (C) 1999 by the So ciety for Gynecologic Investigation.