Suppression of liver tumor growth and metastasis by adiponectin in nude mice through inhibition of tumor angiogenesis and downregulation of rho kinase/IFN-inducible protein 10/matrix metalloproteinase 9 signaling

Purpose: We aimed to investigate the effects of adiponectin on liver cancer growth and metastasis and explore the underlying mechanisms. Experimental Design: An orthotopic liver tumor nude mice model with distant metastatic potential was applied. Either Ad-adiponectin (1 × 10 8; treatment group) or Ad-luciferase (control group) was injected via portal vein after tumor implantation. Tumor growth and metastasis were monitored by Xenogen In vivo Imaging System. Hepatic stellate cell activation by α-smooth muscle actin staining, microvessel density by CD34 staining, macrophage infiltration in tumor tissue, and cell signaling leading to invasion, migration [Rho kinase (ROCK), IFN-inducible protein 10 (IP10), and matrix metalloproteinase 9], and angiogenesis [vascular endothelial growth factor (VEGF) and angiopoietin 1] were also compared. Tumor-nontumor margin was examined under electron microscopy. Direct effects of adiponectin on liver cancer cells and endothelial cells were further investigated by a series of functional studies. Results: Tumor growth was significantly inhibited by adiponectin treatment, accompanied by a lower incidence of lung metastasis. Hepatic stellate cell activation and macrophage infiltration in the liver tumors were suppressed by adiponectin treatment, along with decreased microvessel density. The treatment group had less Ki-67-positive tumor cells and downregulated protein expression of ROCK1, proline-rich tyrosine kinase 2, and VEGF. Tumor vascular endothelial cell damage was found in the treatment group under electron microscopy. In vitro functional study showed that adiponectin not only downregulated the ROCK/IP10/VEGF signaling pathway but also inhibited the formation of lamellipodia, which contribute to cell migration. Conclusion: Adiponectin treatment significantly inhibited liver tumor growth and metastasis by suppression of tumor angiogenesis and downregulation of the ROCK/IP10/matrix metalloproteinase 9 pathway. ©2010 AACR.postprin

A garlic derivative S-allylcysteine suppresses liver tumor growth and metastasis by sensitizing chemotherapy

Background and Objective: A garlic derivative S-allylcysteine (SAC) has anti-cancer effect in human prostate and colon cancers. We aimed to investigate the effect of SAC and combination of chemo-drug on tumorigenesis and metastasis of liver cancer. Materials and Methods: The orthotopic liver tumor model using a metastatic liver cancer cell line MHCC97L labeled with luciferase gene was applied. SAC was given at day 7 after tumor implantation at 1mg/g/day, 2mg/g/day, or 1mg/g/day combined with low dose Cisplatin for 5 weeks. Tumor growth and metastasis were monitored by Xenogen in vivo imaging system. Hepatic stellate cell (HSC) activation and tumor-associated macrophage (TAM) in the tumor tissue were detected by D-SMA and ED1/ED2 staining. Tumor micro-vessel density (MVD) and apoptosis were also analyzed. In vitro functional tests including MTT assay, colony formation assay, cell cycle analysis and apoptosis analysis were performed. Results: The tumor growth was significantly inhibited by SAC combined with Cisplatin treatment at different time points accompanied by lower incidence of lung metastasis compared with other groups. The observation of Xenogen IVIS was confirmed by histopathological examination. The HSC activation by D-SMA staining in the liver tumors was suppressed by SAC and Cisplatin treatment accompanied with less TAM infiltration. Consistent with in vivo study, in vitro functional study also demonstrated that SAC not only induced cell cycle arrest and tumor cell apoptosis, but also significantly sensitized the anti-cancer effect of Cisplatin. Conclusion: SAC treatment significantly inhibited liver tumor growth and metastasis by induction of tumor cell apoptosis and together with sensitization of chemotherapy.link_to_OA_fulltex

Expression significance and functional characterization of homeoprotein Six1 in hepatocellular carcinoma

Homeoprotein Six1 plays an important role on regulation of metastasis in human cancers. The aim of this study was to unravel the role of Six1 in hepatocellular carcinoma (HCC) through clinical and experimental studies. Seventy-two pairs of RNA and 103 pairs of protein from tumor and adjacent nontumor liver tissues of HCC patients after hepatectomy were examined. About 85% and 60% of HCC tumor tissues overexpressed Six1 mRNA and protein, respectively, compared with nontumor liver tissues. No Six1 protein was detected in nontumor liver tissues of HCC patients and normal liver tissues. Increased Six1 protein expression in HCC patients was significantly correlated with pathologic tumor-node-metastasis (pTNM) stage, venous infiltration and poor overall survival. Short hairpin RNA interference approach was used to suppress the expression of Six1 in a metastatic HCC cell line MHCC97L. In vitro functional assays demonstrated that suppression of Six1 expression significantly suppressed the growth rate and proliferation ability of MHCC97L, and markedly decreased its motility and invasiveness. Data from xenograft tumorigenesis model demonstrated that in vivo growth rate of subcutaneous xenograft of MHCC97L was inhibited after suppression of Six1 expression. Experimental and spontaneous metastasis models indicated that suppression of Six1 noticeably reduced the pulmonary metastatic potential of MHCC97L. Our data suggested that Six1 is frequently overexpressed in HCC patients and elevated Six1 protein in HCC patients may be an indication of advanced stage and poor overall survival after hepatectomy. Suppression of Six1 leading to reduction of metastatic ability of metastatic cells implies its potential therapeutic application on treatment of HCC metastasis.link_to_OA_fulltex

Molecular signature linked to acute phase injury and tumor invasiveness in small-for-size liver grafts

Objective: We aimed to explore the precise molecular mechanism of early and invasive tumor growth in a small-for-size graft after liver transplantation and to identify the distinct molecular signature linked to acute-phase injury and late-phase tumor invasiveness. Summary background data: Acute phase small-for-size liver graft injury plays an important role in tumor recurrence after liver transplantation. For prevention of such recurrence, understanding of its underlying mechanism will be important in developing novel therapeutic strategies. Methods: An orthotopic rat liver transplantation model was applied using whole grafts and small-for-size (50%) grafts. The recipients were injected with hepatoma cell lines via the portal vein to mimic tumor recurrence after liver transplantation. Tumor invasive properties were compared between the tumor developed from small and whole graft. Gene signatures of acute phase graft injury (days 1 and 3) and late phase tumor recurrence (days 14 and 21) were screened using cDNA microarray analysis and further confirmed by quantitative RT-PCR. The potential gene candidate CXCL10 was singled out for further functional studies to investigate its role in tumor progression. Results: A number of genes linked to inflammatory responses and tumor invasiveness were found over-expressed in small-for-size liver grafts and/or tumors developed in small liver grafts by cDNA microarray screening. Real-time RT-PCR also confirmed that the gene CXCL10 was over-expressed not only in small-for-size graft at the early phase, but also in tumor from small-for-size graft at the late phase after liver transplantation. In vitro functional studies further confirmed that CXCL10 promoted tumor-invasion-related properties and tumor-associated macrophage activation. Conclusion: CXCL10 over-expression, the distinct gene signature of acute-phase graft injury and tumor invasiveness in small-for-size liver grafts, may contribute to early tumor recurrence after liver transplantation. CXCL10 and its downstream signals may be potential therapeutic targets in the prevention of tumor recurrence after liver transplantation using small-for-size graft. © 2010 Lippincott Williams & Wilkins.link_to_subscribed_fulltex