Co-expression and biological significance of Fas(APO-1,CD95)/Fas ligand by BeWo and JEG-3 choriocarcinoma cell lines

【Objective】 To investigate the hitherto undescribed expression of Fas and FasL in the immortalized human choriocarcinoma cell lines BeWo and NJ-G,and to confirm the mechanism of T cell apoptosis induced by co-culture of choriocarcinoma cell with Jurkat.【Methods】 Receptor and ligand expression was demonstrated using specific antibodies and multiple techniques including confocal immunofluorescence microscopy,flow cytometry,immunoblots,MTT,Trypan blue dye exclusion assay and reverse transcription polymerase chain reaction(RT-PCR).【Results】 ①Fas and FasL were expressed both in 2 human choriocarcinoma cell lines.②The expression of Fas in the level of both gene and protein,was lower in choriocarcinoma cells than that in Jurkat cells,while that of FasL was higher.③The choriocarcinoma cell induced the apoptosis of Jurkat cells in co-culture experiments.The apoptosis rate was increased with time.④The apoptosis rate of Jurkat cells in co-culture assays was decreased from(17.86±5.59)% to(6.88 ±1.05)% after FasL having been blocked with FasL neutralizing antibody NOK-2.【Conclusions】 Choriocarcinoma cells evade immune attack by down regulating the Fas receptor and killing lymphocytes through expression of FasL.Fas/ FasL pathway is one of the mechanisms of immune escape in choriocarcinoma cell cells and may be a new target point of immunological therapy.