Assessment of different trophoblast cell lines as in vitro models for trophoblast development -

Abstract

Background: The placenta is a temporary organ during pregnancy that is involved in insuring optimal growth and development of the fetus. Since the 1980s, there has been a growing interest in the isolation of villous trophoblasts from human placenta for primary culture. Although very interesting, isolated primary trophoblasts have the disadvantage of being extremely difficult to maintain in culture which motivated investigators to generate villous and extravillous trophoblastic cell lines. Nevertheless, when aspiring to extrapolate results they obtain in the trophoblastic cell lines, the scientific community must be cautious as to whether these cell lines are truly representative of the physiologic setting. Aim: Our study raises questions regarding the validity of using the choriocarcinoma cell lines (BeWo, JEG-3, JAR) vs. the extravillous cell line (HTR-8-SVneo) as in vitro model systems for human trophoblast studies.Methods: Immunofluorescence staining was used to investigate the expression of CK7, E-cadherin and vimentin in BeWo, JEG-3, JAR and HTR-8-SVneo cell lines. RT-PCR allowed the measurement of mRNA levels of CK7, EpCAM and vimentin in BeWo, JEG-3, JAR and HTR-8-SVneo while western blots assessed the protein expression of CK7, E-cadherin and vimentin in BeWo, JEG-3, JAR and HTR-8-SVneo.Results: BeWo, JEG-3 and JAR cell lines all expressed CK7, E-cadherin and EpCAM and did not express vimentin while HTR-8-SVneo cell line showed lower expression of CK7 and E-cadherin and expressed vimentin. Additionally, two populations were observed in HTR-8-SVneo cell line: a CK7+-Vimentin- population vs. CK7--Vimentin+ population.Conclusion: Our study indicated that even though BeWo, JEG-3 and JAR cell lines have proved to be epithelial trophoblastic cell lines, HTR-8-SVneo has been disqualified in that regard and results based on this cell line should be controlled in primary trophoblast models.