Fig. 5. The H19/SIRT1/autophagy pathway attenuates the chemosensitivity of CRC cells.

a, b Western blotting was used to detect LC-3I, LC-3II, p62, and SIRT1 expression in HCT8 and HCT116 cells transfected with pcDNA-H19 and/or si-SIRT1. c LC3 aggregation in HCT116 cells transfected with pcDNA-H19 and/or si-SIRT1. Bar scale, 10 μm. d Autophagosomes were observed by transmission electron microscopy in HCT8 and HCT116 cells transfected with pcDNA-H19 and/or si-SIRT1. Bar scale, 2 μm. e, f The cell sensitivity of HCT8 and HCT116 transfected with pcDNA3.1 or pcDNA-H19 to 5-Fu was evaluated using the MTT assay upon exposure to the step-up concentration of 5-Fu with or without downregulation of SIRT1 for 72h. **P<0.01, ***P<0.001. g, h Apoptosis was detected by flow cytometry in HCT8 (g) and HCT116 (h) cells transfected with pcDNA3.1 or pcDNA-H19 with or without downregulation of SIRT1 and treated with 5-Fu. **P<0.01. i Expression of SIRT1 was analyzed by IHC in the CRC tissues and paired adjacent normal samples. j IHC analysis was performed to determine the SIRT1 staining scores in CRC tissues with distinct recurrence status. *P<0.05