Alteration in transforming growth factor-β receptor expression in gallbladder disease: implications of chronic cholelithiasis and chronic Salmonella typhi infection

Gallbladder cancer prevalence is ever increasing with Salmonella typhi chronic infection being one of the predisposing factors. Altered ratios or expression of transforming growth factor-β (TGF-β) receptors and changes in its function are associated with loss in anti-proliferative effects of TGF-β and cancer progression. Using reverse transcriptase polymerase chain reaction we monitor any changes in TGF-β receptor gene expression. We simultaneously screen for S. typhi within the samples. From 73 patients undergoing cholecystectomy 39-50% had significant expression (P<0.05) of TGF-β receptor (TβR)- I and TβR-II during chronic cholelithiasis as compared to the remaining 19-23% with acute chronic cholelithiasis. There was no significant increase in TβR-III receptor expression. Patient’s positive for S. typhi (7/73) did not show any significant changes in expression of these receptors, thus indicating no direct relation in regulating the host TGFβ-signaling pathway. Further analysis on expression of downstream Smad components revealed that patients with up-regulated TGFβ receptor expression show >2-fold increase in the RSmads and Co-Smads with a >2-fold decrease in I-Smads. Thus gain of TβR-I and II expression in epithelial cells of the gallbladder was associated with chronic inflammatory stages of the gallbladder disease.