Growth, morphologic, and invasive characteristics of early and late passages of a human endometrial carcinoma cell line (RL95-2)

Two in vitro passages of a human endometrial adenocarcinoma continuous cell line (RL95-2), an early (subcultured <30 times) and a late passage (subcultured >200 times) have provided an interesting model to study the growth, morphologic, and invasive properties of endometrial tumors. The early passage, which has been shown to be estrogen-receptor positive, has characteristics closely resembling a primary tumor, whereas the estrogen receptor negative late passage exhibits several features of the metastatic phenotype. Compared to the early passage cells, the late passage cells were less serum dependent, formed foci, demonstrated a faster rate of growth (due to their shorter doubling times), and attained higher saturation densities. The late passage cells also displayed an altered morphology which was accompanied by alterations in the distribution of F-actin. Even though early and late passages showed similar invasive potential in an in vitro invasion assay, the late passage cells, by virtue of their several transformed characteristics, maintain distinctive properties compared with their early passage counterparts.