RASSF1A Resensitizes A549-DDP Cell to Cisplatin

Abstract: Low expression of RASSF1A may be a critical cause for acquired chemo resistance of lung cancer. In order to find a biomarker predicting chemo sensitivity of A549 cell to cisplatin， cisplatin-resistant human A549 cells (A549-DDP) were chosed and transfected with a RASSF1A plasmid to enhance the expression of RASSF1A. Semi-quantitative RT-PCR and Western blot analyses were performed to confirm the expression of RASSF1A mRNA or protein before and after cell transfect. Exposing to different concentrations of cispaltin， MTT assays were used to evaluate cell viability and calculated the IC50 value to cisplatin before and after transfect respectively; Clone forming tests were used to evaluated the clone forming ability before and after cell transfect. Exposing to the same concentration of cisplatin， flow cytometric analysis was used to assess apoptosis before and after cell transfect. The results indicated: exposing to cisplatin 24 h， IC50 value to cisplatin decreased greatly in A549-DDP cell with exogenous expression of RASSF1A than that in A549-DDP cell [(39.9±6.3) μmol/L vs (53.0±5.8) μmol/L， P=0.036]; After exposing to cisplatin for 5 days， the clone number of A549-DDP with exogenous expression of RASSF1A was significantly reduced than that of A549-DDP; with the same concentration of cisplatin， the apoptosis percentage increased greatly in A549-DDP with exogenous expression of RASSF1A than that of A549-DDP [(7.10±0.01)% vs (3.80±0.18)%， P=0.002]. The results suggest that low expression of RASSF1A may be a critical cause for acquired chemo resistance of lung cancer and it needs deeply study about RASSF1A acts as biomarker for chemosensitivity of lung cancer patients in clinic.

CSTR: 32200.14.cjcb.2013.04.0004