Gap junctional intercellular communication and connexin43 expression in human ovarian surface epithelial cells and ovarian carcinomas in vivo and in vitro

Gap junctional intercellular communication (GJIC) and the expression of gap junction proteins (connexins) are frequently decreased in neoplastic cells and have been increased by cAMP and retinoids. GJIC and connexin expression were investigated in early passage normal human ovarian surface epithelial (HOSE) cells, human ovarian adenocarcinoma cell lines (CaOV-3, NIH:OVCAR-3, SK-OV-3 and SW626) and surgical specimens of human serous cystadenocarcinomas. We hypothesized that GJIC and connexin expression would be decreased in neoplastic cells and would be increased by cAMP and retinoic acid. Cultured HOSE cells exhibited extensive fluorescent dye-coupling and connexin43 (Cx43) expression; other connexins were not detected. The ovarian adenocarcinoma cell lines had little dye-coupling or connexin expression. Deletions and rearrangements of the Cx43 gene were not detected by Southern blotting in the carcinoma lines. N6, 2'-O-dibutyryladenosine 3',5'-cyclic monophosphate and all-trans-retinoic acid inhibited cell proliferation, but did not enhance GJIC or Cx43 expression. Surface epithelial cells of benign ovaries expressed Cx43, but this expression was barely detectable in ovarian serous cystadenocarcinomas. Thus, normal HOSE cells had extensive GJIC and Cx43 expression whereas ovarian carcinoma cells had less and cAMP and retinoic acid did not change these, although both agents inhibited cell growth.

Detection of genomic alterations in human cervical cancer by two-dimensional gel electrophoresis

Two-dimensional gel electrophoresis was used to comprehensively scan the whole genome of 6 cervical intraepithelial neoplasia (CIN) lesions, 7 cervical squamous cell carcinomas, 1 cervical adenosquamous cell carcinoma, and 2 cervical adenocarcinomas for multiple genetic alterations, such as DNA amplification, chromosome deletion, loss of heterozygosity, and chromosome translocation, as compared with the paired normal tissues. DNA spot analysis of the genomic 2-dimensional gels was performed by a computer color overlay system and by spot recognition software allowing for objective spot comparison and quantitation. Nine spots were found to be amplified in the cervical carcinomas while two amplified spots were detected in the CIN III lesions. Fourteen DNA spots were either reduced in their intensity or absent in cervical carcinomas as compared to their normal paired tissues. Reduction of intensity in 6 spots was observed in the 5 CIN III lesions. These genetic alterations may represent changes in cancer genes that are associated with human cervical carcinogenesis. Further characterization of these alterations may be significant to the understanding of cervical tumorigenesis and to the development of biomarkers for clinical trials in cancer chemoprevention.