Hypoxia and hepatocellular carcinoma: The therapeutic target for hepatocellular carcinoma

Hypoxia enhances proliferation, angiogenesis, metastasis, chemoresistance, and radioresistance of hepatocellular carcinoma (HCC); suppresses differentiation and apoptosis of HCC; and consequently leads to resistance of transarterial embolization (with or without chemotherapy). Because transarterial embolization contributes to angiogenesis via inducing hypoxia, therapy combined with transarterial embolization and antiangiogenic therapy provides a new strategy for the treatment of HCC. Unfortunately, hypoxia leads to the escape of HCC cells from transarterial embolization and antiangiogenic therapy. Thus combined therapy that induces and targets hypoxia may be of benefit to HCC patients. Because angiogenesis plays an important role in recurrence of HCC after resection, antiangiogenic therapy is beneficial to HCC patients following surgical resection of the tumor.     

Thrombin is a therapeutic target for metastatic osteopontin-positive hepatocellular carcinoma

We previously identified osteopontin (OPN) as a promoter and thus a potential therapeutic target for hepatocellular carcinoma (HCC) metastasis. The serine protease thrombin interacts with OPN and can modify its biological activity. To explore the role of thrombin alone or in conjunction with OPN in HCC, we studied the correlation of thrombin levels to HCC prognosis in patients with various OPN levels, and evaluated the effects of OPN fragments generated by thrombin cleavage on proliferation and adhesion of HCC cells. We found that the thrombin level was strongly associated with the metastatic potential of HCC cell lines, and that thrombin was remarkably overexpressed in HCC tissue compared with adjacent nontumor tissue. In addition, HCC tissue from patients with recurrent disease displayed much higher thrombin levels, particularly in those with elevated OPN levels. Only HCCs with elevated OPN levels had a significant correlation between high thrombin levels and overall survival (OS; P < 0.01), or time to recurrence (TTR; P < 0.0001) of HCC. Multivariate analysis revealed that thrombin was an independent prognostic indicator. In vitro assays demonstrated that thrombin promotes the proliferation and adhesion of OPN+ HCC cells. Furthermore, thrombin activated the focal adhesion kinase (FAK) pathway of OPN+ HCC cells, which was blocked by the inhibition of integrin β1. Conclusion: Thrombin plays an important role in OPN-mediated aggressive phenotype of HCC through activation of integrin β1-FAK signaling, and is an independent poor prognostic factor for HCC. Thus, thrombin may be a potential therapeutic target to inhibit HCC metastasis in OPN+ patients.     

Role of the tissue microenvironment as a therapeutic target in hepatocellular carcinoma

Hepatocellular carcinoma is difficult to treat,primarilybecause the underlying molecular mechanisms drivingclinical outcome are still poorly understood.Growingevidence suggests that the tissue microenvironmenthas a role in the biological behavior of the tumor.Themain clinical issue is to identify the best target fortherapeutic approaches.Here,we discuss the hypothesis that the entire tissue microenvironment might beconsidered as a biological target.However,the tissuemicroenvironment consists of several cellular and biochemical components,each of which displays a distinctbiological activity.We discuss the major components ofthis environment and consider how they may interactto promote tumor/host crosstalk.     

c-Met represents a potential therapeutic target for personalized treatment in hepatocellular carcinoma

c-Met, a high-affinity receptor for hepatocyte growth factor (HGF), plays a critical role in cancer growth, invasion, and metastasis. Hepatocellular carcinoma (HCC) patients with an active HGF/c-Met signaling pathway have a significantly worse prognosis. Although targeting the HGF/c-Met pathway has been proposed for the treatment of multiple cancers, the effect of c-Met inhibition in HCC remains unclear. The human HCC cell lines Huh7, Hep3B, MHCC97-L, and MHCC97-H were used in this study to investigate the effect of c-Met inhibition using the small molecule selective c-Met tyrosine kinase inhibitor PHA665752. MHCC97-L and MHCC97-H cells demonstrate a mesenchymal phenotype with decreased expression of E-cadherin and increased expression of c-Met, fibronectin, and Zeb2 compared with Huh7 and Hep3B cells, which have an epithelial phenotype. PHA665752 treatment blocked phosphorylation of c-Met and downstream phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase/Erk pathways, inhibited cell proliferation, and induced apoptosis in c-Met-positive MHCC97-L and MHCC97-H cells. In xenograft models, administration of PHA665752 significantly inhibited c-Met-positive MHCC97-L and MHCC97-H tumor growth, and PHA665752-treated tumors demonstrated marked reduction of both c-Met phosphorylation and cell proliferation. c-Met-negative Huh7 and Hep3B cells were not affected by c-Met inhibitor treatment in vitro or in vivo. In addition, c-Met-positive MHCC97-L and MHCC97-H cells demonstrated cancer stem cell-like characteristics, such as resistance to chemotherapy, tumor sphere formation, and increased expression of CD44 and ABCG2, and PHA665752 treatment suppressed tumor sphere formation and inhibited CD44 expression. Conclusion: c-Met represents a potential target of personalized treatment for HCC with an active HGF/c-Met pathway.     

Novel therapeutic target for cancer stem cells in hepatocellular carcinoma

Cancer is a disease of genetic and epigenetic alterations, which are emphasized as the central mechanisms of tumor progression in the multi-stepwise model. Discovery of rare subpopulations of cancer stem cells (CSCs) has created a new focus in cancer research. The heterogeneity of tumors can be explained with the help of CSCs supported by anti-apoptotic signaling. CSCs mimic normal adult stem cells by demonstrating unique characteristics of self-renewal and pluripotency, and the critical role for tumor growth and resistance to anti-cancer therapy. We found that CD13 was a surface marker for CSCs in human liver cancer cell lines and clinical samples, and that CD13+ CSCs were associated with a hypoxic marker in clinical hepatocellular carcinoma (HCC) sample, suggesting that CD13+ CSCs have the critical role in tumor growth and resistance to anti-cancer therapy in liver cancers. In this review article, we update recent findings regarding the involvement of CSCs, especially in HCC.     

骨桥蛋白:一个值得关注的肝癌转移复发预测指标与干预靶点

骨桥蛋白(osteopontin,OPN)最早从骨基质中分离得到,为一种分泌型非胶原化糖蛋白,富含唾液酸,其部分生物学功能与趋化因子相似.人类编码OPN的基因是一个单一编码基因,具有7个外显子,延伸至大约8 kb核苷酸序列,位于人染色体4q13.OPN为一酸性糖蛋白,富含丝氨酸、天冬氨酸和谷氨酸基,含有一段特殊的精氨酸-甘氨酸-天冬氨酸(RGD)结构域;相对分子质量约为4.4×104.OPN约含30个单糖,其中10个被唾液酸化;其糖基化特点为1个N-连接寡糖链和6个O-连接寡糖链;整个分子磷酸化位点超过28个.OPN参与体内许多生理和病理过程,例如动脉粥样硬化、骨的重塑、血管发生、组织的损伤与修复、动脉内膜增生、心肌坏死、肾结石、肾间质纤维化和某些自身免疫性疾病.     

Non alcoholic steatohepatitis a precursor for hepatocellular carcinoma development

Hepatocellular carcinoma(HCC) is increasing in prevalence and is one of the most common cancers in the world. Chief amongst the risks of attaining HCC are hepatitis B and C infection, aflatoxin B1 ingestion, alcoholism and obesity. The later has been shown to promote non alcoholic fatty liver disease, which can lead to the inflammatory form non alcoholic steatohepatitis(NASH). NASH is a complex metabolic disorder that can impact greatly on hepatic function. The mechanisms by which NASH promotes HCC are only beginning to be characterized. Here in this review, we give an overview of the recent novel mechanisms published that have been associated with NASH and subsequent HCC progression. We will focus our discussion on inflammation and gut derived inflammation and how they contribute to NASH driven HCC.     

Exosomal microRNAs as a potential therapeutic strategy in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is the fifth most com-mon cancer and the second cause of cancer-related death worldwide. The incidence of HCC is constantly increasing in correlation with the rise in diabetes and obesity, arguing for an urgent need for new developments in the treatment of this lethal cancer. Exosomes are small double-membrane vesicles loaded with distinct cargos, particularly small non-coding RNAs called microRNAs, representative of each donor cell and secreted to affect the features of neighboring cells or recipient cells located further away, like in the case of metastasis. A better understanding of the role of exosomes with a microRNA signature in cancer pathogenesis gave rise to the concept of their use as a noninvasive diagnostic biomarker and in the treatment of cancer, including HCC. In this communication, we review recent works that demonstrate that hepatic stellate cells establish an epigenetic communication with liver cancer cells, which affects their pro-malignant features. If naturally secreted patient-derived exosomes show major limitations concerning their clinical use, bio-engineered exosome mimetics that incorporate controlled components and exhibit no protumoral properties could be promising carriers for the treatment of liver cancers, which is the organ preferentially targeted by systemic injection of exosomes.     

Mammalian target of rapamycin as a novel target in the treatment of hepatocellular carcinoma

Several studies have discovered that PI3K/Akt/ mammalian target of rapamycin (mTOR) pathway played an important role in the development of cancer. In this study, we examined the effects of antisense pEGFP-C1-mTOR on cell proliferation, apoptosis and migration of human hepatocellular carcinoma cell lines, HepG2 and SMMC7721 in vitro. We also observed the expression of mTOR and Akt by using RT-PCR and western blot. Our results showed that treatment of cells with antisense pEGFP-C1-mTOR could induce human hepatocellular carcinoma cells' growth inhibition, apoptosis and weaken the migration activity. And we observed that the expression of mTOR was significantly decreased in the cells treated with antisense pEGFP-C1-mTOR and interestingly we discovered that the phosphorylation AKT expression was slightly increased. It indicated that there existed a negative feedback effect which might decrease the therapeutic effects of antisense pEGFP-C1-mTOR. Therefore, we conceive that targeting to inhibit the expression of mTOR in combination with AKT inactivate may increase clinical effectiveness in hepatocellular carcinoma's treatment.     

Ribonuclease 7-driven activation of ROS1 is a potential therapeutic target in hepatocellular carcinoma

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