Pan-mTOR inhibitor MLN0128 is effective against intrahepatic cholangiocarcinoma in mice

Abstract

Background & Aims Intrahepatic cholangiocarcinoma (ICC) is a lethal malignancy without effective treatment options. MLN0128, a second-generation pan-mTOR inhibitor, shows efficacy for multiple tumor types. Methods We established a novel ICC mouse model via hydrodynamic transfection of activated forms of AKT (myr-AKT) and Yap (YapS127A) protooncogenes (that will be referred to as AKT/YapS127A). Genetic approaches were applied to study the requirement of mTORC1 and mTORC2 in mediating AKT/YapS127A driven tumorigenesis. Gemcitabine/Oxaliplatin and MLN0128 were administered in AKT/YapS127A tumor-bearing mice to study their antitumor efficacy in vivo. Multiple human ICC cell lines were used for in vitro experiments. Hematoxylin and eosin staining, immunohistochemistry and immunoblotting were applied for characterization and mechanistic study. Results Co-expression of myr-AKT and YapS127A promoted ICC development in mice. Both mTORC1 and mTORC2 complexes were required for AKT/YapS127A ICC development. Gemcitabine/Oxaliplatin had limited efficacy in treating late stage AKT/YapS127A ICC. In contrast, partial tumor regression was achieved when MLN0128 was applied in the late stage of AKT/YapS127A cholangiocarcinogenesis. Furthermore, when MLN0128 was administered in the early stage of AKT/YapS127A carcinogenesis, it led to disease stabilization. Mechanistically, MLN0128 efficiently inhibited AKT/mTOR signaling both in vivo and in vitro, inducing strong ICC cell apoptosis and only marginally affecting proliferation. Conclusions Altogether, our study suggests that mTOR kinase inhibitors may be beneficial for the treatment of ICC, even in tumors that are resistant to standard of care chemotherapeutics such as gemcitabine/Oxaliplatin based regimen, especially in the subset exhibiting activated AKT/mTOR cascade. Lay Summary We established a novel mouse model of intrahepatic cholangiocarcinoma (ICC). Using this new preclinical model, we evaluated the therapeutic potential of mTOR inhibitor MLN0128 versus Gemcitabine/Oxaliplatin (the standard chemotherapy for ICC treatment). Our study shows the anti-neoplastic potential of MLN0128, suggesting that it may be superior to Gemcitabine/Oxaliplatin based chemotherapy for the treatment of ICC, especially in the tumors exhibiting activated AKT/mTOR cascade.

MicroRNA‐21 and Dicer are dispensable for hepatic stellate cell activation and the development of liver fibrosis

“…F). Second, we used a cholangiocarcinoma model driven by overexpression of activated protein kinase B (AKT) and yes‐associated protein 1 (Yap) and employed either miR‐21 KO mice or miR‐21KD antimirs. By both approaches, we did not observe differences in cholangiocarcinoma development as determined by liver‐to‐body weight ratio, keratin 19 (Krt19)‐positive area, and Krt19 and prominin 1 ( Prom1 ) mRNA expression (http://onlinelibrary.wiley.com/doi/10.1002/hep.29627/suppinfo).…”

“…Mice with Alb‐Cre‐mediated deletion of Pten and Tgfbr2 were used as the model of cholangiocarcinoma, using a floxed miR‐21 allele to simultaneously delete miR‐21 in cells from which cholangiocarcinomas originate. In a second model, cholangiocarcinoma was induced by hydrodynamic tail vein injection of plasmids encoding sleeping beauty transposase, pT3‐myrAKT, and pT3‐YapS127A, as described …”

“…In a second model, cholangiocarcinoma was induced by hydrodynamic tail vein injection of plasmids encoding sleeping beauty transposase, pT3-myrAKT, and pT3-YapS127A, as described. (33) Additional methods are described in the Supporting Material.…”

Celecoxib alleviates AKT/c‐Met‐triggered rapid hepatocarcinogenesis by suppressing a novel COX‐2/AKT/FASN cascade

“…Specific primary antibodies used in immunohistochemistry were listed in Supplementary Table S1. Antibody incubation and visualization of immunoreactivity were conducted as previously described …”

“…Antibody incubation and visualization of immunoreactivity were conducted as previously described. 20…”