Combretastatin A-1 phosphate, a microtubule inhibitor, acts on both hepatocellular carcinoma cells and tumor-associated macrophages by inhibiting the Wnt/β-catenin pathway.

Combretastatin A-1 phosphate (CA1P) is a microtubule polymerization inhibitor that binds to the colchicine-binding site of tubulin. We demonstrated that CA1P has outstanding anti-cancer activity against hepatocellular carcinoma (HCC) in vitro and in vivo. As determined by fluorescence staining and western blots (WBs), CA1P induced reactive oxygen species (ROS) accumulation and apoptosis in HepG2 cells with a down-regulation of Mcl-1. Additional studies indicated that CA1P induced microtubule depolymerization-mediated AKT inactivation, which resulted in GSK-3β activation, Wnt/β-Catenin pathway inhibition, and Mcl-1 down-regulation. The induction of HepG2 cell apoptosis by CA1P was prevented by a GSK-3β-specific inhibitor. Furthermore, immunohistochemistry studies on hepatocellular carcinoma mouse models showed that CA1P had activity against tumor-associated macrophages (TAMs). CA1P induced TAM apoptosis in vitro through the same mechanism observed with HepG2 cells, and it eliminated TAMs in the tumor microenvironment (TME) in vivo. In TME, the expression of TGF-β and TNF-α was also altered. The adoptive transfer of macrophages partly rescued the growth of tumor inhibited by CA1P. These findings indicate that CA1P has great potential to impact both cancer cells and the microenvironment, and our results should accelerate the application of CA1P for HCC therapy in clinic.

Mao J ，Wang D ，Wang Z ，Tian W ，Li X ，Duan J ，Wang Y ，Yang H ，You L ，Cheng Y ，Bian J ，Chen Z ，Yang Y ... -  《-》

WM130 preferentially inhibits hepatic cancer stem-like cells by suppressing AKT/GSK3β/β-catenin signaling pathway.

Ni CX ，Qi Y ，Zhang J ，Liu Y ，Xu WH ，Xu J ，Hu HG ，Wu QY ，Wang Y ，Zhang JP ... -  《Oncotarget》

Inhibition of the Wnt/β-catenin signaling pathway improves the anti-tumor effects of sorafenib against hepatocellular carcinoma.

Sorafenib, a multikinase inhibitor, is currently the only approved drug for advanced hepatocellular carcinoma (HCC). The current study tested the hypothesis whether inhibition of the Wnt/β-catenin signaling pathway could improve the anti-tumor effects of sorafenib in HCC. ICG-001, a small molecule which blocks the interaction of β-catenin with its transcriptional coactivator CBP, dose-dependently enhanced the growth-suppressive and apoptosis-induction effects of sorafenib in multiple HCC cell lines. Downregulation of β-catenin by RNA interference increased sorafenib sensitivity, whereas overexpression of β-catenin reduced sorafenib sensitivity in Huh7 cells. The sorafenib-sensitization effect of short hairpin RNA (shRNA)-mediated β-catenin downregulation in Huh7 cells was attenuated by β-catenin overexpression. Mechanistically, sorafenib combined with ICG-001 or shRNA-mediated β-catenin downregulation augmented the induction of apoptosis, and resulted in a significant downregulation of Mcl-1 in HCC cells. In Huh7 cell mouse xenograft model, the combination of ICG-001 and sorafenib showed a more significant growth-retarding effect than single agent treatment of sorafenib or ICG-001. Our data indicate that inhibition of the Wnt/β-catenin signaling pathway improves the antitumor effects of sorafenib against HCC in vitro and in vivo.

Lin HH ，Feng WC ，Lu LC ，Shao YY ，Hsu CH ，Cheng AL ... -  《-》

Nanoliposome C6-Ceramide Increases the Anti-tumor Immune Response and Slows Growth of Liver Tumors in Mice.

Ceramide, a sphingolipid metabolite, affects T-cell signaling, induces apoptosis of cancer cells, and slows tumor growth in mice. However, it has not been used as a chemotherapeutic agent because of its cell impermeability and precipitation in aqueous solution. We developed a nanoliposome-loaded C6-ceremide (LipC6) to overcome this limitation and investigated its effects in mice with liver tumors. Immune competent C57BL/6 mice received intraperitoneal injections of carbon tetrachloride and intra-splenic injections of oncogenic hepatocytes. As a result, tumors resembling human hepatocellular carcinomas developed in a fibrotic liver setting. After tumors formed, mice were given an injection of LipC6 or vehicle via tail vein every other day for 2 weeks. This was followed by administration, also via tail vein, of tumor antigen-specific (TAS) CD8+ T cells isolated from the spleens of line 416 mice, and subsequent immunization by intraperitoneal injection of tumor antigen-expressing B6/WT-19 cells. Tumor growth was monitored with magnetic resonance imaging. Tumor apoptosis, proliferation, and AKT expression were analyzed using immunohistochemistry and immunoblots. Cytokine production, phenotype, and function of TAS CD8+ T cells and tumor-associated macrophages (TAMs) were studied with flow cytometry, real-time polymerase chain reaction (PCR), and ELISA. Reactive oxygen species (ROS) in TAMs and bone marrow-derived macrophages, induced by colony stimulating factor 2 (GMCSF or CSF2) or colony stimulating factor 1 (MCSF or CSF1), were detected using a luminescent assay. Injection of LipC6 slowed tumor growth by reducing tumor cell proliferation and phosphorylation of AKT, and increasing tumor cell apoptosis, compared with vehicle. Tumors grew more slowly in mice given the combination of LipC6 injection and TAS CD8+ T cells followed by immunization compared with mice given vehicle, LipC6, the T cells, or immunization alone. LipC6 injection also reduced numbers of TAMs and their production of ROS. LipC6 induced TAMs to differentiate into an M1 phenotype, which reduced immune suppression and increased activity of CD8+ T cells. These results were validated by experiments with bone marrow-derived macrophages induced by GMCSF or MCSF. In mice with liver tumors, injection of LipC6 reduces the number of TAMs and the ability of TAMs to suppress the anti-tumor immune response. LipC6 also increases the anti-tumor effects of TAS CD8+ T cells. LipC6 might therefore increase the efficacy of immune therapy in patients with hepatocellular carcinoma.

Li G ，Liu D ，Kimchi ET ，Kaifi JT ，Qi X ，Manjunath Y ，Liu X ，Deering T ，Avella DM ，Fox T ，Rockey DC ，Schell TD ，Kester M ，Staveley-O'Carroll KF ... -  《-》

Dichlorodiphenyltrichloroethane exposure induces the growth of hepatocellular carcinoma via Wnt/β-catenin pathway.

Dichlorodiphenyltrichloroethane (DDT) is a persistent organic pollutant, involved in the progression of many cancers, including liver cancer. However, the underlying mechanism(s) of DDT, especially how low doses DDT cause liver cancer, is poorly understood. In this study, we evaluated the impact of p,p'-DDT on the growth of hepatocellular carcinoma using both in vitro and in vivo models. The present data indicated that the proliferation of HepG2 cells was strikingly promoted after exposed to p,p'-DDT for 4 days. In addition, reactive oxygen species (ROS) content was significantly elevated, accompanied with inhibitions of γ-glutamylcysteine synthetase (γ-GCS) and superoxide dismutase (SOD) activities. Interestingly, the levels of β-catenin and its downstream target genes (c-Myc and CyclinD1) were significantly up-regulated, and co-treatment of NAC, the ROS inhibitor, inhibited these over-expressed proteins. Moreover, the p,p'-DDT-stimulated proliferation of HepG2 cells could be reversed after NAC or β-catenin siRNA co-treatment. Likewise, p,p'-DDT treatment increased the growth of tumor in nude mice, stimulated oxidative stress and Wnt/β-catenin pathway. Our study indicates that low doses p,p'-DDT exposure promote the growth of hepatocellular carcinoma via Wnt/β-catenin pathway which is activated by oxidative stress. The finding suggests an association between low dose DDT exposure and liver cancer growth.

Jin XT ，Song L ，Zhao JY ，Li ZY ，Zhao MR ，Liu WP ... -  《-》