2.9 Western blotting
For Western blot analysis, the total proteins from the colon cells were collected in RIPA lysis buffer (Beyotime, Beijing, China). Samples (40 μg each) were separated onto 12% SDS-PAGE gels and transferred to a PVDF membrane (Millipore Corp., Billerica, MA, USA). Membranes were incubated overnight with related primary antibodies at a 1:1000 dilution.