Early effects of Bacillus Calmette-Guerin on rat bladder cancer cells and normal transitional epithelial cells

Abstract

Objective To explore the mechanism of Bacillus Calmette-Guerin (BCG) for bladder cancer through comparing stimulation of bladder cancer cells and normal bladder transitional epithelial cells with BCG or metabolites.Methods The rat bladder cancer models were established,and the bladder cancer cells and normal transitional epithelial cells were subjected to primary culture.The cancer cells were cultured separately in the normal medium (group A),the BCG medium (group B),the supernatant which was obtained from the culture of normal transitional epithelial cells in the normal medium (group C),the supernatant which was obtained from the culture of normal transitional epithelial cells in the BCG medium (group D),and the supernatant which was obtained from the culture of bladder cancer cells in the BCG medium (group E).The concentrations of interferon (IFN)-γ,tumor necrosis factor (TNF)-α,interleukin (IL)-10 in the supernatant of each group were detected by using enzyme-linked immunosorbent assay (ELISA),and apoptosis was examined by using terminal-deoxynucleo tidyl transferase mediated nick end labeling (TUNEL) and flow cytometry.Results There was no significant difference among groups in the concentrations of IFN-γ (6.5-8.5) ng/L.The concentrations of IL-10 in group B (17.165 ±3.434) ng/Land group E (20.420 ± 2.678) ng/L were significantly higher than the rest three groups.The concentrations of TNF-α in group B (159.887 ±5.854) ng/L and group D (126.227 ±4.812) ng/L were significantly different from the other three groups.No apoptosis was detected in any group.Conclusion BCG can inhibit growth of bladder cancer cells,but cann' t induce apoptosis.The bladder cancer cells can regulate their own growth and escape the attack from the immune cells through the secretion of IL-10,and TNF-α. Key words: Bacillus Calmette-Guerin; Bladder carcinoma; Apoptosis ; Interferon-γ; Tumor necrosis factor-α; Interleukin-10