Ovarian cancer is the sixth most commonly occurring cancer in women. The American Cancer Society has suggested that diet, talc, industrial pollutants, among many other agents, may increase the risk of developing ovarian cancer. However, the implication of talc as a carcinogen has been challenged based upon further epidemiological studies of women who have used talc for extended periods of time with no visible increase in risk for development of ovarian cancer. The purpose of this study was to clarify the role of talc in the etiology of ovarian cancer. Human ovarian cell lines: OSE2a (normal epithelial) and GC1a (normal granulosa) were grown in a humidified 5% CO2 incubator at 37°C. Cells were incubated with 0-10 μM Dimethylbenz(alpha)anthracene (DMBA) or 0-500 μg/ml talc for 24 and 72 hours for the Cell Viability Assay. To demonstrate neoplastic transformation, cells were incubated with varying concentrations of DMBA or talc for 72 hours and the colonies were then enumerated after two weeks of incubation in soft agar (Gut 52:327-333, 2003). DMBA, a known chemical carcinogen, was included as a positive control. Results of the Cell Viability Assays showed that talc caused a significant increase in cell viability in the GC1a cells but did not significantly increase cell viability in OSE2a cells at 72 hours. DMBA caused a significant increase in cell viability in OSE2a cells but not in GC1a cells at 72 hours. Results from the Neoplastic Transformation Assays showed that talc significantly increased the number of transformed colonies in both the GC1a and OSE2a cells. DMBA also increased the number of transformed colonies in both of these cell lines; with a statistically significant increase noted in the OSE2a cell line. Our data thus suggest that talc is capable of inducing neoplastic transformation of both the normal stromal and epithelial ovarian cells in vitro. Studies exploring the mechanism behind these results would be of interest to the field of carcinogenesis. Furthermore, this in vitro model may also be utilized to determine the efficacy of chemopreventative agents in inhibiting neoplastic transformation.
[Proc Amer Assoc Cancer Res, Volume 46, 2005]