[Knock-down of DAB2 interacting protein (DAB2IP) promotes proliferation and inhibits apoptosis of bladder cancer cells].

Objective To study the expression of DAB2 interacting protein (DAB2IP) in human bladder cancer tissues and analyze its relationship with pathological grade and clinical stage, and observe its role in drug resistance of bladder cancer cells. Methods The expression of DAB2IP in primary and recurrent bladder cancers was detected by immunohistochemical staining. RNA interference (RNAi) technique was used to down-regulate the expression of DAB2IP in 5637 and 253J bladder cancer cells. MTT assay and clone formation assay were performed to test the sensitivity of cancer cells to pirarubicin. Flow cytometry was done to detect the apoptosis rate of low-DAB2IP-expressing cells treated with pirarubicin. Results The expression of DAB2IP was negatively correlated with TNM stage, pathological grade and lymph node metastasis of bladder cancer. The expression of DAB2IP in the recurrent bladder cancer was lower than that in the primary bladder cancer. The low expression of DAB2IP in bladder carcinoma cells was related to drug resistance. Knock-down of DAB2IP enhanced the colony formation of bladder cancer cells, reduced the expressions of PARP and caspase-3, increased expressions of Bcl-2 and Mcl-1, reduced the apoptosis of cancer cells and induced chemotherapy tolerance. Conclusion Knock-down of DAB2IP can promote the proliferation and inhibit the apoptosis of bladder cancer cells, and increase the resistance to chemotherapy.