[Mechanism in growth inhibition of quercetin on human bladder cancer cell line]

To investigate the inhibitory mechanism of quercetin on growth of human bladder cancer cell line(BIU-87). BIU-87 cells were cultured in vitro, and co-cultured with varying concentrations of quercetin, and the anti-proliferative activity was determined by CCK-8 assay. Apoptosis of quercetin-induced BIU-87 cells and cell cycle were determined by flow cytometry analysis. Expressions of Bal-2 and Bal-xL, and related proteins in TAK1/JNK signal pathway were measured using Western blot analysis. After treatment with quercetin for 24 h and 48 h, the proliferation of BIU-87 cells was significantly suppressed in a dose-dependent manner according to CCK-8 assay(P<0.05). The flow cytometry analysis indicated that each group of quercetin leads to a significant higher percentage of apoptosis of BIU-87 cells than control group after treatment with quercetin for 24 h and 48 h; In G₀/G₁ period, cells reduced, while the amount of cells in G₂/M period increased, and cells in S period remained the same amount. Expressions of Bal-2, Bal-xL, p-TAK1, p-MKK4/7, p-JNK decreased in BIU-87 cells after treatment with quercetin. Quercetin could inhibit the proliferation and promote the apoptosis of BIU-87 cells. The mechanism may be correlated with the inhibition of TAK1/JNK signaling pathway, which led to the further decrease in expressions of Bal-2 and Bal-xL.