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Substance P (SP) promotes cholangiocyte growth during cholestasis by activating its receptor, NK1R. SP is a proteolytic product of tachykinin (Tac1) and is deactivated by membrane metalloendopeptidase (MME). This study aimed to evaluate the functional role of SP in the regulation of cholangiocarcinoma (CCA) growth. NK1R, Tac1, and MME expression and SP secretion were assessed in human CCA cells and nonmalignant cholangiocytes. The proliferative effects of SP (in the absence/presence of the NK1R inhibitor, L-733,060) and of L-733,060 were evaluated. In vivo, the effect of L-733,060 treatment or MME overexpression on tumor growth was evaluated by using a xenograft model of CCA in nu/nu nude mice. The expression of Tac1, MME, NK1R, PCNA, CK-19, and VEGF-A was analyzed in the resulting tumors. Human CCA cell lines had increased expression of Tac1 and NK1R, along with reduced levels of MME compared with nonmalignant cholangiocytes, resulting in a subsequent increase in SP secretion. SP treatment increased CCA cell proliferation in vitro, which was blocked by L-733,060. Treatment with L-733,060 alone inhibited CCA proliferation in vitro and in vivo. Xenograft tumors derived from MME-overexpressed human Mz-ChA-1 CCA cells had a slower growth rate than those derived from control cells. Expression of PCNA, CK-19, and VEGF-A decreased, whereas MME expression increased in the xenograft tumors treated with L-733,060 or MME-overexpressed xenograft tumors compared with controls. The study suggests that SP secreted by CCA promotes CCA growth via autocrine pathway. Blockade of SP secretion and NK1R signaling may be important for the management of CCA.

A S L D A b st ra ct s BGJ398, a pan-FGFR inhibitor currently being employed in human trials, resulted in a significant increase in cellular apoptosis. Tumor tissue from mice sacrificed 10 weeks after biliary oncogene transduction of AKT and YAP also demonstrated increased expression of FGFR 1-4. BGJ398 treatment resulted in a significant reduction in tumor burden and increase in tumor cell apoptosis as assessed by the TUNEL assay in our mouse model of CCA. In Conclusion, YAP is a critical oncogene in CCA and promotes biliary carcinogenesis, in part, via upregulation of FGFR. In a murine genetic model of CCA, the FGFR specific inhibitor BGJ398 significantly reduces tumor burden by inducing apoptosis. Thus, inhibition of FGFR represents a promising therapeutic approach in YAP-driven human CCA.

A S L D A b st ra ct s BGJ398, a pan-FGFR inhibitor currently being employed in human trials, resulted in a significant increase in cellular apoptosis. Tumor tissue from mice sacrificed 10 weeks after biliary oncogene transduction of AKT and YAP also demonstrated increased expression of FGFR 1-4. BGJ398 treatment resulted in a significant reduction in tumor burden and increase in tumor cell apoptosis as assessed by the TUNEL assay in our mouse model of CCA. In Conclusion, YAP is a critical oncogene in CCA and promotes biliary carcinogenesis, in part, via upregulation of FGFR. In a murine genetic model of CCA, the FGFR specific inhibitor BGJ398 significantly reduces tumor burden by inducing apoptosis. Thus, inhibition of FGFR represents a promising therapeutic approach in YAP-driven human CCA.

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.