PDGF essentially links TGF-beta signaling to nuclear beta-catenin accumulation in hepatocellular carcinoma progression

The cooperation of Ras - extracellular signal-regulated kinase/mitogen-activated protein kinase and transforming growth factor (TGF)-beta signaling provokes an epithelial to mesenchymal transition (EMT) of differentiated p19(ARF) null hepatocytes, which is accompanied by a shift in malignancy and gain of metastatic properties. Upon EMT, TGF-beta induces the secretion and autocrine regulation of platelet-derived growth factor (PDGF) by upregulation of PDGF-A and both PDGF receptors. Here, we demonstrate by loss-of-function analyses that PDGF provides adhesive and migratory properties in vitro as well as proliferative stimuli during tumor formation. PDGF signaling resulted in the activation of phosphatidylinositol-3 kinase, and furthermore associated with nuclear beta-catenin accumulation upon EMT. Hepatocytes expressing constitutively active beta-catenin or its negative regulator Axin were employed to study the impact of nuclear beta-catenin. Unexpectedly, active beta-catenin failed to accelerate proliferation during tumor formation, but in contrast, correlated with growth arrest. Nuclear localization of beta-catenin was accompanied by strong expression of the Cdk inhibitor p16(INK4A) and the concomitant induction of the beta-catenin target genes cyclin D1 and c-myc. In addition, active beta-catenin revealed protection of malignant hepatocytes against anoikis, which provides a prerequisite for the dissemination of carcinoma. From these data, we conclude that TGF-beta acts tumor progressive by induction of PDGF signaling and subsequent activation of beta-catenin, which endows a subpopulation of neoplastic hepatocytes with features of cancer stem cells..     

Molecular pathways in hepatocellular carcinoma

Research over the past decade has unraveled important molecular pathways involved in hepatocellular carcinoma (HCC), and several chromosomal and genetic aberrations have been identified to be responsible for initiation of the carcinogenic process. HBx protein and HCV core protein appear to play a pivotal role in hepatocarcinogenesis related to hepatitis B virus and hepatitis C virus, respectively. These viral oncoproteins allow cells to bypass some of the multi-steps in hepatocarcinogenesis, accounting for the etiological role of the two viruses in HCC. Understanding of the molecular pathways of HCC facilitates the development of novel molecular strategies for chemoprevention and therapy of HCC.     

Signaling pathways in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer, and its mortality rate is the third highest after lung and colon cancer. Its incidence has significantly increased in the last two decades in close relation with the ubiquitous spread of viral hepatitis. HCC has a poor prognosis since less than 30% of newly diagnosed patients will be eligible for potential curative treatment. Molecular therapies such as sorafenib, a BRAF/ VEGFR/PDGFR tyrosine kinase inhibitor, have shown to improve survival in patients with advanced HCC. This recent success has spurred intensive research aimed at identifying aberrant activation of signaling pathways. This approach will probably aid to define previously unrecognized oncogenic addiction loops in HCC and in developing more effective targeted therapies.     

肝癌细胞中PI3K信号通路对VEGF表达的影响

目的:研究磷脂酰肌醇3-激酶(PI3K)信号通路在肝癌细胞血管内皮生长因子(VEGF)表达调控中的作用.方法: 体外培养高转移性人肝癌细胞株HCCLM3,分为对照组、PI3K特异性抑制剂LY294002浓度5μmol/L组,LY294002浓度10μmol/L及20μmol/L组,处理6小时后,采用逆转录聚合酶链反应(RT-PCR)技术检测VEGF mRNA表达的变化.结果: LY294002可使肝癌细胞HCCLM3的VEGF mRNA的表达下降,且这种抑制作用随着LY294002浓度增大而增大(P<0.01),呈现剂量移赖性关系.结论: LY294002可以抑制肝癌细胞株HCCLM3中VEGF的表达,肝癌细胞VEGF的表达调控受PI3K信号通路调控.     

IGFBP-3 gene expression and estrogen receptor status in human breast carcinoma.

Insulin-like growth factors (IGF) I and II are potent mitogens for breast carcinoma proliferation. IGF-mediated proliferative activity can be markedly enhanced by the presence of specific IGF-binding proteins (IGFBPs). IGFBP-3 has been shown to enhance IGF-mediated growth in a number of systems. Studies have demonstrated IGFBP-3 secretion only in estrogen receptor (ER)-negative breast carcinoma cell lines while IGFBP-3 could not be detected in media conditioned by ER-positive cell lines. We investigated whether a relationship exists between ER status and IGFBP-3 mRNA expression in human breast carcinoma biopsy specimens. We have detected IGFBP-3 mRNA in breast carcinoma tissue obtained from patients utilizing in situ hybridization. Quantitation of IGFBP-3 mRNA levels was performed utilizing image cytometry. There was a significantly higher expression of IGFBP-3 mRNA in ER-negative breast carcinoma specimens when compared to the ER-positive specimens. Whether this higher expression of IGFBP-3 mRNA and presumed secretion of IGFBP-3 by ER-negative tumors play a role in the rapid proliferation and poor prognosis of these tumors remains to be determined.     

Clusterin facilitates metastasis by EIF3I/Akt/MMP13 signaling in hepatocellular carcinoma

Clusterin (CLU) is a stress-induced chaperone that confers proliferative and survival advantages to cancer cells. However, effects and molecular mechanisms of CLU in hepatocellular carcinoma (HCC) metastasis are still unknown. In this study, HCC tissue array (n = 198) was utilized to investigate correlation between CLU expression and clinicopathological features. Overexpression of CLU in HCC tissues was correlated with shorter overall survival and higher tumor recurrence. In vitro and in vivo assays demonstrated that silencing CLU attenuated the invasion and metastasis of HCC cells, whereas ectopic overexpression of CLU resulted in the forced metastasis of HCC cells. We also revealed that CLU activated Akt signaling through complexing with eukaryotic translation initiation factor 3 subunit I (EIF3I), which in turn promoted matrix metalloproteinase 13 (MMP13) expression and HCC metastasis. Positive correlations between CLU and MMP13, p-Akt, or EIF3I were found in HCC tissues. We further observed that CLU knockdown using the CLU inhibitor OGX-011 significantly suppressed HCC metastasis in two metastatic models through inhibiting EIF3I/Akt/MMP13 signaling. These findings indicate that CLU is an independent predictive factor for prognosis of HCC and it facilitates metastasis through EIF3I/Akt/MMP13 signaling. CLU suppression using OGX-011 may represent a promising therapeutic option for suppressing HCC metastasis.     

肝癌细胞中P13K信号通路对VEGF表达的影响

目的：研究磷脂酰肌醇3-激酶（P13K）信号通路在肝癌细胞血管内皮生长因子（VEGF）表达调控中的作用。方法：体外培养高转移性人肝癌细胞株HCCLM3,分为对照组、P13K特异性抑制剂LY294002浓度5μmol／L组,LY294002浓度10μmol／L及20μmol／L组,处理6小时后,采用逆转录聚合酶链反应（RT—PCR）技术检测VEGF mRNA表达的变化。结果：LY294002可使肝癌细胞HCCLM3的VEGFmRNA的表达下降,且这种抑制作用随着LY294002浓度增大而增大（P〈0．01）,呈现剂量移赖性关系。结论：LY294002可以抑制肝癌细胞株HCCLM3中VEGF的表达,肝癌细胞VEGF的表达调控受P13K信号通路调控。     

SIRT1 promotes tumorigenesis of hepatocellular carcinoma through PI3K/PTEN/AKT signaling

SIRT1 is the human orthologue of SIR2, a conserved NAD-dependent protein deacetylase that regulates longevity in yeast and in Caenorhabditis elegans. Overexpression of SIRT1 in cancer tissue, compared with normal tissue, has been demonstrated, suggesting that SIRT1 may act as a tumor promoter. The function of SIRT1 in liver cancer has not been elucidated. In the present study, SIRT1 re-expression or knockdown was induced in hepatoma cell lines and liver normal cell lines. Our study demonstrated that overexpression of SIRT1 promoted mitotic entry of liver cells, cell growth and proliferation and inhibited apoptosis. The apoptosis involved caspase-3 and caspase-7, and was related to the PTEN/PI3K/AKT signaling pathway. The results demonstrate that SIRT1 promotes tumorigenesis of hepatocellular carcinoma (HCC) through the PTEN/PI3K/AKT signaling pathway. SIRT1 may serve as a novel target for selective killing of cancer versus normal liver cells.     

MicroRNA-21 suppresses PTEN and hSulf-1 expression and promotes hepatocellular carcinoma progression through AKT/ERK pathways

MicroRNAs (miRNAs) have been believed to associate with malignant progression including cancer cell proliferation, apoptosis, differentiation, angiogenesis, invasion and metastasis. However, the functions of miRNAs are intricate, one miRNA can directly or indirectly target multiple genes and function as oncogene or tumor suppressor gene. In this study, we found that miR-21 inhibits PTEN and human sulfatase-1 (hSulf-1) expression in hepatocellular carcinoma (HCC) cells. The hSulf-1 is a heparin-degrading endosulfatase, which can inhibit the heparin binding growth factor-mediated signaling transduction into cells. Therefore, miR-21-mediated suppression of both hSulf-1 and PTEN led to activation of AKT/ERK pathways and epithelial–mesenchymal transition (EMT) in HCC cells, and finally enhance the activity of HCC cell proliferation and movement and promote HCC xenograft tumor growth in mouse models. These findings may provide candidate targets for prevention and treatment of HCC.     

The EMT signaling pathways in endometrial carcinoma

Endometrial cancer (EC) is the most common gynecologic malignancy of the female genital tract and the fourth most common neoplasia in women. In EC, myometrial invasion is considered one of the most important prognostic factors. For this process to occur, epithelial tumor cells need to undergo an epithelial to mesenchymal transition (EMT), either transiently or stably, and to differing degrees. This process has been extensively described in other types of cancer but has been poorly studied in EC. In this review, several features of EMT and the main molecular pathways responsible for triggering this process are investigated in relation to EC. The most common hallmarks of EMT have been found in EC, either at the level of E-cadherin loss or at the induction of its repressors, as well as other molecular alterations consistent with the mesenchymal phenotype-like L1CAM and BMI-1 up-regulation. Pathways including progesterone receptor, TGF??, ETV5 and microRNAs are deeply related to the EMT process in EC.     

肝细胞癌中FGF信号通路的作用机制及靶向治疗

肝细胞癌作为一种常见的恶性肿瘤,在肿瘤相关致死原因中排第三位,其发生率和死亡率在近十年来呈上升趋势。成纤维细胞生长因子是一类具有基因多效性功能的多肽细胞因子家族,其参与了肝硬化的发展,同时也是肝细胞癌的危险因素之一。本文通过系统复习相关文献,总结了成纤维细胞生长因子在肝细胞癌发生、发展过程中的分子机制,并讨论了其在肝癌靶向治疗中的潜在靶点。     

Galectin-3 expression is induced in cirrhotic liver and hepatocellular carcinoma

Galectins are a family of beta-galactoside-binding animal lectins. In particular, a widely studied member galectin-3, previously designated as epsilonBP, CBP35, Mac-2, L-29 and L-34, has been associated with assorted processes such as cell growth, tumor transformation and metastasis. Galectin-3 is expressed in various tissues and organs but is significantly absent in normal hepatocytes. However, evaluation of patient liver biopsies for galectin-3 expression resulted in the finding that hepatocellular carcinoma (HCC) frequently expressed significant levels of this lectin (76% immunohistochemically positive). Further investigation revealed that galectin-3 expression in HCC is independent of whether the patient had prior hepatitis B virus infection: 14 of 18 HCC cases from HBV- patients, and 5 of 7 cases from HBV patients demonstrated positive galectin-3 immunohistochemistry. However, co-transfection studies using a galectin-3 promoter construct and an HBV-X protein (HBV-X) expression vector demonstrated that galectin-3 expression can occur through transactivation of the lectin promoter by HBV-X. Based on presently known properties of this lectin, it is possible that deregulated expression of galectin-3 can result in tumor transformation and invasiveness, or confer propensity for tumor cell survival. In addition, galectin-3 was abundantly expressed in cirrhotic liver in peripheral distribution within regenerating nodules. Such galectin-3 expression in rapidly proliferating hepatocytes in cirrhotic liver may be a result of the high mitotic index. Alternatively, it is possible that proliferating cells expressing galectin-3 are in the process of being transformed, thus indicating an early neoplastic event.     

P-glycoprotein expression in hepatocellular carcinoma

In hepatocellular carcinoma cell lines, the intensity of staining with the monoclonal antibody C-219 to the multidrug-resistant gene (mdr1) product P-glycoprotein and the intensity of the band at a molecular weight of 170 KDa on Western blot were associated closely with resistance to Adriamycin but not with the resistance to cis-dichlorodiamine platinum (CDDP). In clinical specimens, noncancerous liver tissue was regularly stained with this antibody on the biliary canalicular front of the hepatocyte cell membrane. In liver cancer tissue, however, regular staining as in the noncancerous regions of the liver was observed in only 16% of the patients, irregular staining was seen in only 24%, and no staining was seen at all in 60%. Staining of P-glycoprotein with the C-219 antibody is technically simple and is useful for studying the role of P-glycoprotein in drug-resistant hepatocellular carcinoma. © 1993 Wiley-Liss, Inc.     

Unresectable hepatocellular carcinoma treated with radiotherapy and/or chemoembolization

The purpose of our study was to evaluate the outcome, patterns of failure, and toxicity for patients with unresectable hepatocellular carcinoma (HCC) treated with radiotherapy, transcatheter arterial chemoembolization (TACE), or combined TACE and radiotherapy. Forty-two patients with unresectable HCC were treated with combined radiotherapy and TACE (TACE+RT group, 17 patients), radiotherapy alone (RT group, 9 patients), or with TACE alone (TACE group, 16 patients). Mean dose of radiation was 46.9 +/- 5.8 Gy in a daily fraction of 1.8 to 2 Gy, directed only to the cancer-involved areas of the liver. TACE was performed with a combination of Lipiodol, doxorubicin, cisplatin, and mitomycin C, followed by Gelfoam or Ivalon embolization. Tumor size was smaller in the TACE group (mean: 5.4 cm) compared with the TACE+RT group (8.6 cm) and the RT group (13.1 cm) (P = 0.0003). The median follow-up was 24 months in the TACE+RT group, 28 months in the RT group, and 23 months in the TACE group. Survival was significantly worse for patients treated with radiotherapy alone due to the selection bias of patients with more advanced disease and compromised condition in this group. In contrast, the TACE+RT and TACE groups had comparable survival (two-year rates: TACE+RT 58%, TACE 56%, P = 0.69). The local control rate for the treated tumors was similar in the TACE+RT and TACE groups (P = 0.11). The intrahepatic recurrence outside the treated tumors was common and similar between these two groups (P = 0.48). The extrahepatic progression-free survival was significantly shorter for patients in the TACE+RT group than in the TACE group (two-year rates: TACE+RT 36%, TACE 100%, P = 0.002). Seven patients died from complications of treatment. Local radiotherapy may be added to treat patients with unresectable HCC, and the control of progression of the treated tumors was promising even in patients with large hepatic tumors. Survival of patients with combined TACE and radiotherapy was similar to that with TACE as the only treatment, while a significant portion of the patients treated with radiotherapy developed extrahepatic metastasis.     

Analysis of the expression,function and signaling of glycogen phosphorylase isoforms in hepatocellular carcinoma

Glycogen phosphorylase (GP) is an essential enzyme for glycolysis via the glycogen degradation pathway. It consists of three isoforms: PYGB (brain form), PYGL (liver form) and PYGM (muscle form). Although the abnormal expression of GP is associated with a variety of tumors, its relationship with hepatocellular carcinoma (HCC) and whether it can be used as a prognostic marker of HCC remains unclear. In the present study, the expression levels of PYGB, PYGL and PYGM were analyzed. It was found that the expression levels of PYGB in tumor tissues were higher than those in normal tissues, particularly in HCC. The high expression of PYGB (hazard ratios=1.801; 95% confidence interval: 1.266-2.562) could predict the poor prognosis of HCC patients but not PYGL and PYGM. Inhibition of PYGB with GP inhibitor CP91149 significantly suppressed the HCC cell proliferation in the HCC cell model. In addition, combination treatment with sorafenib, a standard treatment for HCC, showed a great inhibition on tumor growth and angiogenesis. These findings suggested that PYGB may be used as a therapeutic and prognostic indicator for HCC.