TGF-β1 Regulated the A549 Cells Sensitivity to Cisplatin through DNMT1

Abstract: TGF-β1 is closely associated with the occurrence， development and apoptosis of carcinogenesis. As the key regulative enzyme of DNA methylation， DNMTs play an important role in the occurrence of tumor and drug-resistance. The expression of SPARC in tumor is always reduced for aberrantly methylation. In order to demonstrate the resistive mechanism of cisplatin， human lung adenocarcinoma A549 cells were cultured. After treated with TGF-β1， the changes of DNMTs and SPARC mRNA levels were detected by RT-PCR， and the effect of TGF-β1 on A549 cell’s viability and sensitivity to cisplatin were evaluated too. Results showed that after treated with 5 ng/mL and 10 ng/mL TGF-β1 for 24 h， mRNA expressions of DNMT1 were reduced greatly (P<0.01， P<0.001)， and SPARC were increased greatly (P<0.001， P<0.001); After exposed to different concentrations of cisplatin for 24 h， the IC50 of 5 ng/mL and 10 ng/mL TGF-β1 groups [(12.34±0.36) μmol/L， (10.93±0.69) μmol/L] were decreased greatly than that of negative control [(21.54±1.21) μmol/L] (P<0.01， P<0.01). The clone formation number of 5 ng/mL and 10 ng/mL TGF-β1 groups were decreased greatly than that of negative control with different concentrations of cisplatin; The apoptosis fractions of 5 ng/mL and 10 ng/mL TGF-β1 groups were obviously higher than that of negative control (P<0.05， P<0.01) with 15 μmol/L cisplatin for 24 h. The present study indicated that TGF-β1 could decrease the expression of DNMT1 in A549 cells， then increase its sensitivity to cisplatin with the higher expression of SPARC， and finally， reverse the malignant phenotype of A549 cells successfully. These findings provide a new idea for further study on the cisplatin-resistance mechanism of lung cancer.

CSTR: 32200.14.cjcb.2014.11.0006