Low-dose paclitaxel modulates the cross talk between the JNK and Smad signaling in primary biliary fibroblasts.

Abstract

The objective of this study was to explore the molecular mechanism underlying the occurrence of benign bile duct stricture and the target of low-dose paclitaxel in the prevention of benign bile duct stricture. Under the stimulation of transforming growth factor beta 1, the expression of collagen type I and connective tissue growth factor were detected on isolated primary fibroblasts. The phosphorylation levels of JNK and Smad2L were detected using Western blot. The effect of low-dose paclitaxel on the transforming growth factor beta 1-induced inhibition of type I collagen and connective tissue growth factor expression and JNK and Smad2L phosphorylation was also observed. Transforming growth factor beta 1 induced the secretion of type I collagen and connective tissue growth factor as well as JNK phosphorylation in biliary fibroblasts. The JNK inhibitor or siRNA-Smad2 inhibited the transforming growth factor beta 1-induced secretion of type I collagen and connective tissue growth factor. Low-dose paclitaxel inhibited the expression of type I collagen induced by transforming growth factor beta 1 and may inhibit the secretion of collagen in biliary fibroblasts. The activation of JNK/Smad2L induced by transforming growth factor beta 1 is involved in the occurrence of benign bile duct stricture that is mediated by the overexpression of type I collagen and connective tissue growth factor, and low-dose paclitaxel may inhibit the phosphorylation of JNK/Smad2L.