The clinical significance of the expression of breast cancer resistance protein gene in hepatocellular carcinoma tissue and the effect of inhibiting its expression on the proliferation and apoptosis of hepatocellular carcinoma cells

Abstract

Objective To investigate the relationship between the expression of breast cancer resistance protein (BCRP) and the clinicopathological features in hepatocellular carcinoma (HCC) and the influence of the BCRP expression on the proliferation and apoptosis of HCC cells. Methods To detect the expression of BCRP in hepatocellular carcinoma tissues by reverse transcriptase-polymerase chain reaction (RT-PCR), and analyze the relationship with clinicopathological parameters; BCRP-small interfering RNA (siRNA) was transfected into human hepatoma SMMC-7721 cells by Lipofectamine™ 2000 liposome mediated method; cell proliferation, apoptosis and BCRP, proliferation cell nuclear antigen (Ki-67), B cell lymphoma/leukemia-2 associated X protein (bax), Notch1 and Hes1 protein expression were detected by methyl thiazol tetrazolium (MTT) method, flow cytometry and Western blotting, respectively. Results The expression of BCRP in HCC was not related to the sex, age and tumor size of HCC patients, and it was related to pathological grade, clinical stage and metastasis of tumor; expression of BCRP in SMMC-7721 cells after BCRP-siRNA was transfected cells was inhibited in the level of transcription and translation; cell proliferation (0.287±0.022) and expression of Ki-67 (0.142±0.018), Notch1 (0.162±0.021) and Hes1 (0.111±0.015) protein in BCRP-siRNA group were significantly lower than Control group (0.411±0.026, 0.258±0.026, 0.462±0.032, 0.241±0.023; Pproliferation=0.001, PKi-67=0.001, PNotch1=0.000, PHes1=0.001), the apoptosis rate (14.63±0.88)% and the expression of bax protein (0.324±0.034) was significantly higher than Control group ([1.32±0.15)%, 0.106±0.012; Papoptosis=0.000, Pbax=0.000]. Conclusion The expression of BCRP is related to pathological grade, clinical stage and metastasis of HCC, inhibition of its expression can reduce the proliferation of hepatocellular carcinoma cells and induce cell apoptosis, the mechanism is related to the regulation of Ki-67, bax expression and Notch1 signaling pathway. Key words: Breast cancer resistance protein gene; Clinical significance; Liver cancer; Apoptosis; Signal pathway