Fig. 4. The effects of SIRT1 silencing on the chemoresistance of CDDP-resistant NSCLC cells. (A) The mRNA expression of SIRT1 in CDDP-sensitive and CDDP-resistant NSCLC patients was detected by qRT-PCR. (B) The protein level of SIRT1 in H1299 or H1299/CDDP cells was measured by western blot. (C) The protein level of SIRT1 in H1299/CDDP cells transfected with si-SIRT1 or si-NC was examined by western blot. (D–F) H1299/CDDP cells were transfected with si-NC or si-SIRT1. MTT and flow cytometry assays were carried out to determine IC50 value, cell proliferation, and apoptosis. (G and H) Western blot and FITC-LC3 punctate formation assays were performed to assess cell autophagy. *P < 0.05.