γ-secretase inhibitor inhibits bladder cancer cell drug resistance and invasion by reducing epithelial-mesenchymal transition

A previous study by our group demonstrated that the expression levels of Notch 1 and Jagged 1 in bladder cancer cells was significantly lower compared with those in normal bladder mucosa, while the expression levels of Notch 1 and Jagged 1 in invasive bladder cancer were higher compared with those in superficial bladder cancer. The present study investigated the effect of the Notch signaling pathway on the drug resistance and invasiveness of bladder cancer cells. It was demonstrated that complete inhibition of the Notch signaling pathway induced significant morphological changes and inhibited cell proliferation and migration (P<0.05). Reverse transcription quantitative polymerase chain reaction and western blot analyses revealed that the mRNA and protein expression levels of E-cadherin were upregulated (P<0.05) and the mRNA and protein expression levels of N-cadherin, vimentin and a-smooth muscle actin were downregulated (P<0.05). The present study concluded that complete inhibition of the Notch signaling pathway inhibited cell proliferation and invasion, and reduced drug resistance in bladder cancer cells, a phenomenon which may be associated with the inhibition of the epithelial-mesenchymal transition.