OBJECTIVETo explore the effect of folate on cell proliferation and apoptosis as well as on DNA methylation, expression of mRNA and protein of fragile histidine triad (FHIT)gene in cervical cancer cells.

METHODSCervical cancer cell lines including CaSki (HPV16-positive) and C33A (HPV-negative)were cultured in vitro with different folate concentrations. Cell proliferation and apoptosis were determined by viable cell counting and flow cytometry while FHIT gene DNA methylation was used with methylation specific PCR (MSP). Both gene expression of FHIT protein and mRNA were detected by Western blot and Real-time PCR, respectively.

RESULTSFolate could inhibit the proliferation and promote the apoptosis in two kinds of cervical cancer cells. The number of viable cells decreased (C33A:r = 0.98, P < 0.001; CaSki:r = 0.98, P < 0.001) and the apoptosis rate increased (C33A:r = 0.98, P < 0.001; CaSki:r = 0.99, P < 0.001) along with the increase of folate concentration. FHIT gene DNA methylation showed all positive at the folate concentration levels of 1 µg/ml and 10 µg/ml, partially positive at 100 µg/ml and 250 µg/ml, but negative at 500 µg/ml and 1 000 µg/ml in both C33A and CaSki cells. Comparing with the control group, the mRNA or protein relative expression levels of FHIT gene in different folate concentrations were statistically significant in two kinds of cells, and showing that the FHIT gene mRNA expression (C33A:r = 0.96, P < 0.001; CaSki:r = 0.94, P < 0.001) and protein expression (C33A:r = 0.96, P < 0.001; CaSki:r = 0.97, P < 0.001) both increased along with the increase of folate concentration.

CONCLUSIONOur findings indicated that adequate folate seemed to be able to effectively inhibit the proliferation of cervical cancer cells and facilitate their apoptosis in vitro, so would reverse the aberration mRNA and protein expression of FHIT gene.