Inhibition of invasion and metastasis of hepatocellular carcinoma cells via targeting RhoC in vitro and in vivo

Modulating the Crosstalk between the Tumor and Its Microenvironment Using RNA Interference: A Treatment Strategy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with one of the highest mortality rates among solid cancers. It develops almost exclusively in the background of chronic liver inflammation, which can be caused by viral hepatitis, chronic alcohol consumption or an unhealthy diet. Chronic inflammation deregulates the innate and adaptive immune responses that contribute to the proliferation, survival and migration of tumor cells. The continuous communication between the tumor and its microenvironment components serves as the overriding force of the tumor against the body's defenses. The importance of this crosstalk between the tumor microenvironment and immune cells in the process of hepatocarcinogenesis has been shown, and therapeutic strategies modulating this communication have improved the outcomes of patients with liver cancer. To target this communication, an RNA interference (RNAi)-based approach can be used, an innovative and promising strategy that can disrupt the crosstalk at the transcriptomic level. Moreover, RNAi offers the advantage of specificity in comparison to the treatments currently used for HCC in clinics. In this review, we will provide the recent data pertaining to the modulation of a tumor and its microenvironment by using RNAi and its potential for therapeutic intervention in HCC.

Inhibition of Phosphatidylinositol 3-Kinase γ by IPI-549 Attenuates Abdominal Aortic Aneurysm Formation in Mice

OBJECTIVE

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway plays a pivotal role in abdominal aortic aneurysm (AAA). However, systemic inhibition of this pathway causes serious side effects, thus limiting the clinical use of pan-PI3K inhibitors. In this study, it was hypothesised that the γ subunit of PI3K plays an important role in the PI3K/AKT signalling pathway during AAA, and that specifically targeting PI3Kγ may prevent this process.

METHODS

Aortic specimens were collected from AAA patients and organ donors. Furthermore, a classical AAA model in male C57BL/6 mice was created via an intra-aortic porcine pancreatic elastase (PPE) infusion and aortas were collected. A specific PI3Kγ inhibitor, IPI-549, was administered to mice orally. The protein expression level of PI3Kγ was examined by immunohistochemistry and western blotting. The aortic leukocytes were examined by immunohistochemistry and flow cytometry.

RESULTS

PI3Kγ protein levels were elevated in the aortas of AAA patients and PPE infused mice. Three color immunofluorescence staining revealed the predominant area of PI3Kγ by T cells and macrophages in aneurysmal aortas. IPI-549 treatment significantly prevented AAA formation in mice. Aortic macrophages, T cells and neo-angiogenesis were significantly reduced in mice treated with IPI-549 compared with vehicle treated PPE infused mice. Flow cytometry analysis also revealed that CD45⁺ leukocytes and CD45⁺ F4/80⁺ macrophages in IPI-549 treated mouse aortas decreased dramatically. Additionally, IPI-549 treatment inhibited the phosphorylation of AKT in experimental aneurysmal lesions.

CONCLUSION

Specific inhibition of PI3Kγ limits AAA formation. Targeting PI3Kγ prevents inflammatory cell infiltration through inhibition of AKT phosphorylation in AAA.

MicroRNAs Involved in Metastasis of Hepatocellular Carcinoma: Target Candidates, Functionality and Efficacy in Animal Models and Prognostic Relevance

Hepatocellular carcinoma (HCC) is responsible for the second-leading cancer-related death toll worldwide. Although sorafenib and levantinib as frontline therapy and regorafenib, cabazantinib and ramicurimab have now been approved for second-line therapy, the therapeutic benefit is in the range of only a few months with respect to prolongation of survival. Aggressiveness of HCC is mediated by metastasis. Intrahepatic metastases and distant metastasis to the lungs, lymph nodes, bones, omentum, adrenal gland and brain have been observed. Therefore, the identification of metastasis-related new targets and treatment modalities is of paramount importance. In this review, we focus on metastasis-related microRNAs (miRs) as therapeutic targets for HCC. We describe miRs which mediate or repress HCC metastasis in mouse xenograft models. We discuss 18 metastasis-promoting miRs and 35 metastasis-inhibiting miRs according to the criteria as outlined. Six of the metastasis-promoting miRs (miR-29a, -219-5p, -331-3p, 425-5p, -487a and -1247-3p) are associated with unfavourable clinical prognosis. Another set of six down-regulated miRs (miR-101, -129-3p, -137, -149, -503, and -630) correlate with a worse clinical prognosis. We discuss the corresponding metastasis-related targets as well as their potential as therapeutic modalities for treatment of HCC-related metastasis. A subset of up-regulated miRs -29a, -219-5p and -425-5p and down-regulated miRs -129-3p and -630 were evaluated in orthotopic metastasis-related models which are suitable to mimic HCC-related metastasis. Those miRNAs may represent prioritized targets emerging from our survey.

miR-330-5p targets SPRY2 to promote hepatocellular carcinoma progression via MAPK/ERK signaling

MicroRNAs (miRNAs) have been identified as critical modulators of cell proliferation and growth, which are the major causes of cancer progression including hepatocellular carcinoma (HCC). Our previous miRNA microarray data have shown that miR-330-5p was always upregulated in HCC. However, the accurate role of miR-330-5p in HCC is still uncertain. Here, we report that miR-330-5p expression is upregulated in HCC tissues and cell lines, and is associated with tumor size, tumor nodule number, capsule formation and Tumor Node Metastasis (TNM) stage in HCC patients. Overexpression of miR-330-5p promotes proliferation and growth of HCC cells in vitro and in vivo, while miR-330-5p knockdown has the inverse effect. Moreover, using miRNA databases and dual luciferase report assay, we find miR-330-5p directly binds to the 3′-untranslated region (3′-UTR) of Sprouty2 (SPRY2). Then we find the novel biofunctional role of SPRY2 inactivation in promoting HCC progression. Finally, we confirm that miR-330-5p suppresses SPRY2 to promote proliferation via mitogen-activated protein kinases (MAPK)/extracellular regulated kinase (ERK) signaling in HCC. Taken together, our findings demonstrate the critical role of miR-330-5p in promoting HCC progression via targeting SPRY2 to activate MAPK/ERK signaling, which may provide a novel and promising prognostic marker and therapeutic target for HCC.

Variant 2 of KIAA0101, antagonizing its oncogenic variant 1, might be a potential therapeutic strategy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignant tumors worldwide and effective therapies, including molecular therapy, remain elusive. Our previous work demonstrates that oncogenic KIAA0101 transcript variant (tv) 1 promotes HCC development and might be a HCC therapeutic target. However, the function of another KIAA0101 variant, KIAA0101 tv2, remains unknown. In this study, we reported that KIAA0101 tv2 was highly expressed in adjacent non-tumorous liver tissues (NTs) compared to HCC tissues. In vivo and in vitro results showed that KIAA0101 tv2 decreased cell survival, colony formation, tumor xenografts, migration, and invasion, as well as induced cell cycle arrest and apoptosis. Interestingly, it could inhibit the function of KIAA0101 tv1 by partially down-regulating KIAA0101 tv1, acting similar to KIAA0101 tv1 short hairpin RNA (shRNA). Further studies illustrated that KIAA0101 tv2 could increase the activity of p53 by competing with KIAA0101 tv1 for P53 binding. In conclusion, KIAA0101 tv2 exerts anti-tumor activity in HCC and acts as an endogenous competitor of tumor-associated KIAA0101 tv1. KIAA0101 tv2 has a potential to work as a therapeutic drug targeting the KIAA0101 tv1 in HCC.

TR4 nuclear receptor suppresses HCC cell invasion via downregulating the EphA2 expression

Early studies indicated that testicular nuclear receptor 4 (TR4) could function as a suppressor in the transcriptional regulation of the HBV core gene expression, which might then influence the development of hepatocellular carcinoma (HCC). The direct linkage between TR4 and HCC progression, however, remained unclear. Here, via a human clinical sample survey, we found that 13 of the 18 HCC patients studied had lower TR4 expression in metastatic lesions than in matched primary HCC lesions, suggesting that TR4 may play a negative role in HCC metastasis. Results from in vitro cell migration/invasion studied confirmed that TR4 could suppress HCC cell migration/invasion. Mechanism dissection revealed that TR4 might function through downregulating ephrin type-A receptor 2 (EphA2) expression at the transcriptional level via direct binding to the TR4REs located on the 5' promoter of EphA2 to suppress HCC cell migration/invasion. Targeting the EphA2 via EphA2-siRNA partially reversed the enhanced HCC cell migration/invasion with confirmed TR4 knockdown. Notably, results from preclinical studies using in vivo mouse model with orthotopic xenograft of HCC LM3 cells also confirmed the in vitro findings. Taking these findings together, preclinical studies using multiple in vitro HCC cell lines and an in vivo mouse model all led to the conclusion that TR4 may function as a suppressor of HCC metastasis and that targeting this newly identified TR4-EphA2 signaling may improve our ability to suppress HCC metastasis.

YMO1 suppresses invasion and metastasis by inhibiting RhoC signaling and predicts favorable prognosis in hepatocellular carcinoma

Previous studies have shown that 4.1 proteins, which are deregulated in many cancers, contribute to cell adhesion and motility. Yurt/Mosaic eyes-like 1 (YMO1) is a member of 4.1 protein family but it is unclear whether YMO1 plays a role in tumor invasion. This study aimed to investigate the effects of YMO1 on hepatocellular carcinoma (HCC) and attempted to elucidate the underlying molecular mechanisms. YMO1 expression in HCC tissues and its correlation with clinicopathological features and postoperative prognosis was analyzed. The results showed that YMO1 was down-regulated in the highly metastatic HCC cell line and in human tumor tissues. Underexpression of YMO1 indicated poor prognosis of HCC patients. Restoration of YMO1 expression caused a significant decrease in cell migration and invasiveness in vitro. In vivo study showed that YMO1 reduced liver tumor invasion and metastasis in xenograft mice. YMO1 directly inhibited RhoC activation. YMO1 expression in HCC was regulated by PAX5. Analysis of YMO1 expression levels in human HCC patients revealed a significant correlation of YMO1 expression with PAX5 and RhoC. Our findings revealed that YMO1 predicts favorable prognosis and the data suggest that YMO1 suppresses tumor invasion and metastasis by inhibiting RhoC activity.

JARID2 promotes invasion and metastasis of hepatocellular carcinoma by facilitating epithelial-mesenchymal transition through PTEN/AKT signaling

JARID2 is crucial for maintenance of pluripotency and differentiation of embryonic stem cells. However, little is known about the role of JARID2 in metastasis of hepatocellular carcinoma (HCC). This study found that JARID2 expression was significantly higher in HCC tissues than that in adjacent non-tumor liver tissues (ANLTs), and its expression level correlated with HCC metastasis. High JARID2 expression was significantly correlated with multiple tumor nodules, high Edmondson-Steiner grade, microvascular invasion, advanced TNM stage and advanced BCLC stage (all P < 0.05) and indicated poor prognosis of HCC in training and validation cohorts (all P < 0.05) totaling 182 patients. High JARID2 expression was an independent and significant risk factor for disease-free survival (DFS; P = 0.017) and overall survival (OS; P = 0.041) after curative liver resection in training cohort, and also validated as an independent and significant risk factor for DFS (P = 0.033) and OS (P = 0.031) in validation cohort. Moreover, down-regulation of JARID2 dramatically inhibited HCC cell migration, invasion, proliferation in vitro and metastasis in vivo, whereas overexpression of JARID2 significantly increased migration, invasion, proliferation in vitro and metastasis in vivo. Mechanistically, the data showed that JARID2 exerted its function by repressing PTEN expression through increasing H3K27 trimethylation (H3K27me3) at PTEN promoter region, which subsequently resulted in activation of protein kinase B (AKT) and enhanced epithelial-mesenchymal transition (EMT). In conclusion, this study revealed that JARID2 promotes invasion and metastasis of HCC by facilitating EMT through PTEN/AKT signaling.

Tetraspanin-8 promotes hepatocellular carcinoma metastasis by increasing ADAM12m expression

Recent evidence indicates that tetraspanin-8 (TSPAN8) promotes tumor progression and metastasis. In this study, we explored the effects of TSPAN8 and the molecular mechanisms underlying hepatocellular carcinoma (HCC) metastasis using various HCC cell lines, tissues from 149 HCC patients, and animal models of HCC progression. We showed that elevated expression of TSPAN8 promoted HCC invasion in vitro and metastasis in vivo, but did not influence HCC cell proliferation in vitro. Increased TSPAN8 expression in human HCC was predictive of poor survival, and multivariate analyses indicated TSPAN8 expression to be an independent predictor for both postoperative overall survival and relapse-free survival. Importantly, TSPAN8 enhanced HCC invasion and metastasis by increasing ADAM12m expression. We therefore conclude that TSPAN8 and ADAM12m may be useful therapeutic targets for the prevention of HCC progression and metastasis.

Inhibition of Phosphatidylinositol 3-kinease suppresses formation and progression of experimental abdominal aortic aneurysms

Accumulating evidence suggests an important role of Phosphatidylinositol 3-kinease (PI3K) pathway in inflammatory cells infiltration. Given  the essential role of inflammatory cells infiltration during the formation and progression of abdominal aortic aneurysm (AAA), to investigate the possibility of preventing AAA formation and progression via targeting PI3K is anticipated. Here, experimental AAAs was created in rats by transient intraluminal porcine pancreatic elastase (PPE) infusion into the infrarenal aorta firstly. AAAs rats were administrated with vehicle or Wortmannin during the period of day 0 to day 28 after PPE infusion. The aortic diameter of rats treated with Wortmannin was significantly smaller than those treated with vehicle. Meanwhile, Elastin destruction score and SMC destruction score were significantly decreased in rats treated with Wortmannin. Furthermore, histological analysis revealed infiltration of inflammatory cells were significantly reduced in rats treated with Wortmannin. Finally, the mRNA expression of PI3K and protein expression of pAKT in human abdominal aneurismal aorta tissues was elevated as compare to normal aorta. Our study revealed that PI3K inhibitor suppresses experimental AAAs formation and progression, through mechanisms likely related to impairing inflammation cells infiltration and median elastin degradation. These findings indicated that PI3K inhibitor may hold substantial translation value for AAA diseases.

Role of the lncRNA ABHD11-AS1 in the tumorigenesis and progression of epithelial ovarian cancer through targeted regulation of RhoC

BACKGROUND

There is increasing evidence in support of the role of lncRNAs in tumor cell proliferation, differentiation and apoptosis.

METHODS

We examined the expression of the lncRNA ABHD11-AS₁ in epithelial ovarian cancer (EOC) tissues and normal ovarian tissues by real-time quantitative PCR (qRT-PCR). After inducing ABHD11-AS₁ downregulation by small interfering RNA (siRNA) or ABHD11-AS₁ overexpression by plasmid transfection, we examined the EOC cell phenotypes and expression of related molecules.

RESULTS

Expression of the lncRNA ABHD11-AS₁ in EOC tissues was higher than that in normal ovarian tissue. It was positively associated with the tumor stage (stage I/II vs. stage III/IV), and it was lower in the well-differentiated group than in the poorly/moderately differentiated group. Overexpression of ABHD11-AS₁ in the ovarian cancer cell lines A2780 and OVCAR3 promoted ovarian cancer cell proliferation, invasion and migration, and inhibited apoptosis. Silencing of ABHD11-AS₁ had the opposite effect. Subcutaneous injection of tumor cells in nude mice showed that ABHD11-AS₁ could significantly promote tumor growth. In addition, intraperitoneal injection of tumor cells in the nude mice resulted in an increase in the metastatic ability of the tumor. Further, overexpression of ABHD11-AS₁ upregulated the expression of RhoC and its downstream molecules P70s6k, MMP2 and BCL-xL. Silencing of ABHD11-AS₁ had the opposite effect. The RNA pull-down assay showed that ABHD11-AS₁ can combine directly with RhoC. Silencing of RhoC was found to inhibit the cancer-promoting effects of lncRNA ABHD11-AS₁. Thus, it seems that RhoC is a major target of the lncRNA ABHD11-AS₁.

CONCLUSIONS

This is the first study to demonstrate the role of RhoC in the tumor-promoting effects of the lncRNA ABHD11-AS₁. The present findings shed light on new therapeutic targets for ovarian cancer treatment.

MicroRNA-372 inhibits endometrial carcinoma development by targeting the expression of the Ras homolog gene family member C (RhoC)

Here we explore the role of microRNA-372 (miR-372) in tumorigenesis and development of endometrial adenocarcinoma (EC) and analyze the underlying mechanism. We found that miR-372 expression is much lower in EC than normal endometrial specimens. Cell function experiments demonstrated that miR-372 overexpression suppressed cell proliferation, migration, and invasion, and led to a G1 phase arrest and promoted the apoptosis of endometrial carcinoma cells in vitro. The nude mouse xenograft assay demonstrated that miR-372 overexpression suppressed tumor growth. RT-PCR and Western blot assays detected the expression of known targets of miR-372 in other malignant tumors and found Cyclin A1 and Cyclin-dependent Kinase 2 (CDK2) was downregulated by miR-372. Bioinformatic predictions and dual-luciferase reporter assays found that RhoC was a possible target of miR-372. RT-PCR and Western blot assays demonstrated that miR-372 transfection reduced the expression of RhoC, matrix metalloproteinase 2 (MMP2) and MMP9, while it increased the expression of cleaved poly (ADP ribose) polymerase (PARP) and bcl-2-associated X protein (Bax). The cell function experiments that transfected siRNA with RhoC showed the same trend as those which were transfected with miR-372. Taken together, our results demonstrated for the first time that miR-372 suppresses tumorigenesis and the development of EC; RhoC is a new and potentially important therapeutic target.

Identification of an aptamer through whole cell-SELEX for targeting high metastatic liver cancers

Hepatocellular carcinoma (HCC) is one of the most deadly human cancers due to its ability of invasion and metastasis. Thus, the approaches to identify potential compounds that inhibit invasion and metastasis of HCC are critical for treatment of this disease. In the present study, we used HCCLM9 cells with high metastatic potential and MHCC97L with low metastatic potential as a model system to study the molecular mechanisms of HCC metastasis. By applying cell- Systematic Evolution of Ligands by Exponential enrichment (SELEX) against living cells, we used HCCLM9 as target cells and MHCC97L cells as control to screen a group of HCC metastasis- and cell-specific DNA aptamers. One of selected aptamers, LY-1, could specifically bind to metastatic HCC with a dissociation constant (Kd) in nanomolar range. In vitro studies demonstrated that LY-1 can recognize and bind to membrane protein of metastatic HCC cells. Furthermore, QD605 labeled LY-1 aptamer could recognize HCC cells in both local liver cancer tissues and pulmonary metastatic sites in a xenograft model of HCC with pulmonary metastasis. Further biochemical and immunostaining studies showed that LY-1 could selectively bind to a subpopulation of more metastatic cells in HCCLM9 cells, which express more CK19 and vimentin. Finally, treatment of highly metastatic cells with LY-1 led to reduced migration and invasiveness of HCCLM9 cells in vitro and suppression of xenograft growth in vivo. Taken together, the present study demonstrated the tumor targeting and tumor suppressive effects of LY-1, which could be a promising molecular probe for metastatic HCC and a potential candidate of chemotherapy for metastatic HCC.

Ack1 overexpression promotes metastasis and indicates poor prognosis of hepatocellular carcinoma

Despite the substantial data supporting the oncogenic role of Ack1, the predictive value and biologic role of Ack1 in hepatocellular carcinoma (HCC) metastasis remains unknown. In this study, both correlations of Ack1 expression with prognosis of HCC, and the role of Ack1 in metastasis of HCC were investigated in vitro and in vivo. Our results showed that Ack1 was overexpressed in human HCC tissues and cell lines. High Ack1 expression was associated with HCC metastasis and determined as a significant and independent prognostic factor for HCC after liver resection. Ack1 promoted HCC invasion and metastasis in vitro and in vivo. Mechanistically, we confirmed that Ack1 enhanced invasion and metastasis of HCC via EMT by mediating AKT phosphorylation. In conclusion, our study shows Ack1 is a novel prognostic biomarker for HCC and promotes metastasis of HCC via EMT by activating AKT signaling.

Novel roles of TMEM100: inhibition metastasis and proliferation of hepatocellular carcinoma

Transmembrane protein 100 (TMEM100) was activated by ALK1/TGF-β signaling. We found that TMEM100 was decreased in hepatocellular carcinoma (HCC) tissues and in highly metastatic cell lines. Overexpressed of TMEM100 inhibited invasion, migration and proliferation. Low levels of TMEM100 were associated with cirrhosis, tumor size, Tumor nodule number, TNM stage, BCLC stage, Edmondson-Steiner Stage and vein invasion. Furthermore, TMEM100 was an independent risk factor for overall survival (P = 0.03) and disease-free survival (P = 0.019). The current findings suggest that TMEM100 functions as a tumor suppressor in HCC metastasis and proliferation.

Progression of systemic chemotherapy with oxaliplatin-containing regimens for advanced hepatocellular carcinoma in China

Hepatocellular carcinoma (HCC) characterized by insidious onset is a highly invasive malignance and has a rapid progress. The majority of patients, especially in Asian countries, present with locally advanced or distant metastatic disease at diagnosis and are not eligible for local treatment. Before the publication of the EACH study results showing the survival benefits of the FOLFOX 4 regimen in Chinese patients with advanced HCC, no chemotherapeutical drug or regimen was considered as systemic chemotherapy standard for this group of patients due to the lack of evidence-based recommendations. Oxaliplatin-containing regimens have shown clinical activity against advanced HCC with an acceptable safety profile. The aim of this article is to present a review of the scientific evidence mainly originating from China that supports the recommendation of oxaliplatin-based regimens for the treatment of Chinese patients with advanced HCC.

A novel microtubule de-stabilizing complementarity-determining region C36L1 peptide displays antitumor activity against melanoma in vitro and in vivo

Short peptide sequences from complementarity-determining regions (CDRs) of different immunoglobulins may exert anti-infective, immunomodulatory and antitumor activities regardless of the specificity of the original monoclonal antibody (mAb). In this sense, they resemble early molecules of innate immunity. C36L1 was identified as a bioactive light-chain CDR1 peptide by screening 19 conserved CDR sequences targeting murine B16F10-Nex2 melanoma. The 17-amino acid peptide is readily taken up by melanoma cells and acts on microtubules causing depolymerization, stress of the endoplasmic reticulum and intrinsic apoptosis. At low concentrations, C36L1 inhibited migration, invasion and proliferation of B16F10-Nex2 cells with cell cycle arrest at G2/M phase, by regulating the PI3K/Akt signaling axis involving Rho-GTPase and PTEN mediation. Peritumor injection of the peptide delayed growth of subcutaneously grafted melanoma cells. Intraperitoneal administration of C36L1 induced a significant immune-response dependent anti-tumor protection in a syngeneic metastatic melanoma model. Dendritic cells stimulated ex-vivo by the peptide and transferred to animals challenged with tumor cells were equally effective. The C36 V_L CDR1 peptide is a promising microtubule-interacting drug that induces tumor cell death by apoptosis and inhibits metastases of highly aggressive melanoma cells.

MicroRNA-125b attenuates epithelial-mesenchymal transitions and targets stem-like liver cancer cells through small mothers against decapentaplegic 2 and 4

Emerging evidence suggests that epithelial-mesenchymal transitions (EMTs) play important roles in tumor metastasis and recurrence. Understanding molecular mechanisms that regulate the EMT process is crucial for improving treatment of hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) play important roles in HCC; however, the mechanisms by which miRNAs target the EMT and their therapeutic potential remains largely unknown. To better explore the roles of miRNAs in the EMT process, we established an EMT model in HCC cells by transforming growth factor beta 1 treatment and found that several tumor-related miRNAs were significantly decreased. Among these miRNAs, miR-125b expression was most strongly suppressed. We also found down-regulation of miR-125b in most HCC cells and clinical specimens, which correlated with cellular differentiation in HCC patients. We then demonstrated that miR-125b overexpression attenuated EMT phenotype in HCC cancer cells, whereas knockdown of miR-125b promoted the EMT phenotype in vitro and in vivo. Moreover, we found that miR-125b attenuated EMT-associated traits, including chemoresistance, migration, and stemness in HCC cells, and negatively correlated with EMT and cancer stem cell (CSC) marker expressions in HCC specimens. miR-125b overexpression could inhibit CSC generation and decrease tumor incidence in the mouse xenograft model. Mechanistically, our data revealed that miR-125b suppressed EMT and EMT-associated traits of HCC cells by targeting small mothers against decapentaplegic (SMAD)2 and 4. Most important, the therapeutic delivery of synthetic miR-125b mimics decreased the target molecule of CSC and inhibited metastasis in the mice model. These findings suggest a potential therapeutic treatment of miR-125b for liver cancer.

CONCLUSION

miR-125b exerts inhibitory effects on EMT and EMT-associated traits in HCC by SMAD2 and 4. Ectopic expression of miR-125b provides a promising strategy to treat HCC.

Effects of benzo[a]pyrene exposure on human hepatocellular carcinoma cell angiogenesis, metastasis, and NF-κB signaling

BACKGROUND

Benzo[a]pyrene (B[a]P) is a common environmental and foodborne pollutant. Although the carcinogenicity of high-dose B[a]P has been extensively reported, the effects of long-term B[a]P exposure at lower environmental doses on cancer development are less understood.

OBJECTIVES

We investigated the impact of B[a]P on human hepatocellular carcinoma (HCC) progression at various levels of exposure and identified a potential intervention target.

METHODS

We used a model based on human HCC cells exposed to various concentrations of B[a]P (i.e., 0.01, 1, or 100 nM) for 1 month to examine the effects of B[a]P on cell growth, migration, invasion, and angiogenicity. A bioluminescent murine model was established to assess tumor metastasis in vivo.

RESULTS

Chronic B[a]P exposure did not alter HCC cell growth but promoted cell migration and invasion both in vitro and in vivo. There was an negative association between B[a]P exposure and the survival of tumor-bearing mice. In addition, B[a]P-treated HCC cells recruited vascular endothelial cells and promoted tumor angiogenesis, possibly through elevating vascular endothelial growth factor secretion. Furthermore, the NF-κB pathway may be an adverse outcome pathway associated with the cumulative effects of B[a]P on HCC metastasis.

CONCLUSIONS

These findings a) indicate that B[a]P has effects on HCC progression; b) identify a possible adverse outcome pathway; and c) contribute to a better understanding of the adverse effects of chronic exposure of B[a]P to human health.

RhoGTPases - A novel link between cytoskeleton organization and cisplatin resistance

For more than three decades, platinum compounds have been the first line treatment for a wide spectrum of solid tumors. Yet, cisplatin resistance is a major impediment in cancer therapy, and deciphering the mechanisms underlying chemoresistance is crucial for the development of novel therapies with enhanced efficacy. The Rho subfamily of small GTPases plays a significant role in cancer progression, and a growing body of evidence points toward the involvement of these proteins in anticancer drug resistance, including cisplatin resistance. The cycling between active and inactive states, governed by the balance between their GEFs, GAPs and GDIs, RhoGTPases, acts as molecular switches with a pivotal role in actin cytoskeleton organization. The Rho subfamily of proteins is involved in many key cellular processes including adhesion, vesicular trafficking, proliferation, survival, cell morphology and cell-matrix interactions. Although RhoA, RhoB and RhoC are highly homologous and share some upstream regulators and downstream effectors, they each have different roles in cancer progression and chemoresistance. While RhoA and RhoC are upregulated in many tumors and can stimulate transformation, RhoB appears to exhibit tumor suppressor characteristics with proapoptotic effects. In the current review, we discuss the role of Rho subfamily of proteins in cancer, and focus on their involvement in intrinsic and acquired drug resistance.

Cyclin A2, a novel regulator of EMT

Our previous work showed that Cyclin A2 deficiency promotes cell invasion in fibroblasts. Given that the majority of cancers emerge from epithelia, we explored novel functions for Cyclin A2 by depleting it in normal mammary epithelial cells. This caused an epithelial to mesenchymal transition (EMT) associated with loss of cell-to-cell contacts, decreased E-Cadherin expression and increased invasive properties characterized by a reciprocal regulation of RhoA and RhoC activities, where RhoA-decreased activity drove cell invasiveness and E-Cadherin delocalization, and RhoC-increased activity only supported cell motility. Phenotypes induced by Cyclin A2 deficiency were exacerbated upon oncogenic activated-Ras expression, which led to an increased expression of EMT-related transcriptional factors. Moreover, Cyclin A2-depleted cells exhibited stem cell-like properties and increased invasion in an in vivo avian embryo model. Our work supports a model where Cyclin A2 downregulation facilitates cancer cell EMT and metastatic dissemination.

miR-503 regulates metastatic function through Rho guanine nucleotide exchanger factor 19 in hepatocellular carcinoma

BACKGROUND

Our previous work described a metastasis-related microRNAs expression profiling and revealed miR-503 regulating metastatic function in hepatocellular carcinoma (HCC) cells. Here, we investigate to define the mechanism of miR-503 regulating metastasis in HCC.

MATERIALS AND METHODS

The expressions of miR-503 in HCC cell lines and clinical tissues with different metastatic potential were investigated. Meanwhile, a metastatic human HCC cell BALB/c nude mice model was used to investigate whether miR-503 regulates metastasis of HCC in vivo. Furthermore, luciferase activity of reporter gene, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), fluorescence-activated cell sorting analysis (FACS), and invasion assay were carried out to characterize the mechanism of miR-503 regulating metastasis in HCC.

RESULTS

We confirmed the negative correlation between miR-503 expression and metastatic potential of HCC in cell lines and in clinical HCC tissues. We also showed that overexpression of miR-503 resulted in inhibition of proliferation and metastasis of HCC in vivo. Furthermore, we demonstrated that ARHGEF19 is a direct target gene of miR-503. Finally, our results indicated that ARHGEF19 overcomes the suppressive influence of miR-503 in HCC cells.

CONCLUSIONS

Our results suggest an important role of miR-503 in inhibiting metastasis of HCC through deregulating ARHGEF19.

Inhibition of rho-kinase by fasudil suppresses formation and progression of experimental abdominal aortic aneurysms

Objective

Accumulating evidence suggests that inflammatory cell infiltration is crucial pathogenesis during the initiation and progression of abdominal aortic aneurysm (AAA). Given Rho-kinase (ROCK), an important kinase control the actin cytoskeleton, regulates the inflammatory cell infiltration, thus, we investigate the possibility and mechanism of preventing experimental AAA progression via targeting ROCK in mice porcine pancreatic elastase (PPE) model.

Methods and Results

AAA was created in 10-week-old male C57BL/6 mice by transient intraluminal porcine pancreatic elastase infusion into the infrarenal aorta. The mRNA level of RhoA, RhoC, ROCK1 and ROCK2 were elevated in aneurismal aorta. Next, PPE infusion mice were orally administrated with vehicle or ROCK inhibitor (Fasudil at dose of 200 mg/kg/day) during the period of day 1 prior to PPE infusion to day 14 after PPE infusion. PPE infusion mice treated with Fasudil produced significantly smaller aneurysms as compare to PPE infusion mice treated with vehicle. AAAs developed in all vehicle-treated groups within 14 days, whereas AAAs developed in six mice (66%, 6/9) treated with Fasudil within 14 days. Furthermore, our semi-quantitative histological analysis revealed that blood vessels and macrophages were significantly reduced in Fasudil treated mice during the AAA progression. Finally, when mice with existing AAAs were treated with Fasudil, the enlargement was nearly completely suppressed.

Conclusion

Fasudil inhibits experimental AAA progression and stabilize existing aneurysms, through mechanisms likely related to impaired mural macrophage infiltration and angiogenesis. These findings suggest that ROCK inhibitor may hold substantial translational value for AAA diseases.

HBx-dependent activation of Twist mediates STAT3 control of epithelium-mesenchymal transition of liver cells

This study investigated the molecular mechanisms of liver cells with HBx expression on epithelium-mesenchymal transition (EMT) change using Western blot analysis and Transwell assay to assess EMT-related protein expression and cell mobility. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were used to test the Twist promoter containing different STAT3 binding loci. Electrophoretic mobility band-shift assay (EMSA) was used to detect Twist activity. Results showed that HBx expression affected the EMT-related protein expression and the cell mobility of liver cancer cells (MHCC97) and liver cells (HL-7702) in vitro or in vivo. These proteins exhibited reversed expression to a certain extent after Twist inhibition. In addition, the wound-healing capability and the mobility of HL-7702/HBx cells were lower than those treated with control-siRNA. The expressions of p-STAT3 and Twist were positively correlated with HBx expression. The second STAT-3 binding sequence in the Twist promoter region of the HL-7702/HBx cells was the first locus. Twist activity in the HL-7702/HBx2 cells was higher than that in HL-7702 cells. Moreover, the activity decreased when the cells were treated with HBx-siRNA to inhibit HBx expression, or with STAT3 inhibitor to reduce STAT3 activation. Therefore, Twist is essential for the regulation of the mobility of liver cells with HBx expression. HBx activates the Twist promoter by activating STAT3 and promotes EMT occurrence in liver cells.

WD40 repeat-containing 62 overexpression as a novel indicator of poor prognosis for human gastric cancer

AIM

WD40 repeat-containing 62 (WDR62) is a centrosome-associated gene involved in cell cycling and proliferation. However, the role of WDR62 in human malignancies remains unknown. The present study aimed to identify the role, if any, of WDR62 in the pathogenesis of human gastric cancer (GC).

METHODS

WDR62 expression in 372 cases of human GC and eight GC cell lines was determined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), immunohistochemistry and Western blotting. Correlations between WDR62 expression and clinicopathological characteristics, as well as GC prognosis were determined. WDR62 regulation of GC cell proliferation, invasion, migration and cell cycle distribution were studied both in vitro and in vivo.

RESULTS

WDR62 expression was significantly increased in GC tissues and cell lines and was associated with poor differentiation and prognosis of GC. WDR62 expression was elevated in GC multidrug resistant cells. Suppressing WDR62 significantly decreased cell proliferation and induced G2/M phase arrest of GC cells. Consistently, WDR62 knockdown inhibited gastric carcinogenesis in nude mice. Regulation of Akt/p38-mitogen-activated protein kinase (MAPK)/multidrug resistance gene 1 (MDR1) expression and activation by WDR62 contributed to the chemoresistance of GC cells. WDR62 overexpresses in GC and the suppression of WDR62 inhibits GC cell growth by inducing G2/M cell cycle arrest.

CONCLUSION

WDR62 may be a novel prognostic marker and a potential chemotherapy target for GC.

The role of RhoC in ovarian epithelial carcinoma: a marker for carcinogenesis, progression, prognosis, and target therapy

BACKGROUND

Ras homolog gene family member C (RhoC) is a small G protein/guanosine triphosphatase involved in tumor mobility, invasion, and metastasis.

METHODS

After RhoC siRNA transfection, we measured the changes in phenotypes and some relevant molecules in ovarian carcinoma cell, OVCAR3. The mRNA and protein expression of RhoC was detected in ovarian tumors.

RESULTS

RhoC siRNA transfection resulted in low growth, G1 arrest, and apoptotic induction in the OVCAR3 in comparison with the control and mock. Following RhoC knockdown, there was reduced mRNA or protein expression of protein kinase B (Akt), signal transducer and activator of transcription 3 (stat3), bcl-xL, surviving and phosphorylated p70S6 kinase (p-p70s6k), while the converse was true for Bax and caspase-3. Lovastatin induced apoptosis, suppressed proliferation, migration and invasion, and disrupted lamellipodia formation in OVCAR3. Lovastatin exposure induced lower RhoC, bcl-2, matrix metalloproteinase-9 (MMP-9), survivin, Akt, bcl-xL, vascular endothelial growth factor (VEGF), and p-p70s6k expression in OVCAR3 compared to the control, but higher caspase-3 and Bax expression. RhoC mRNA and protein expression was significantly higher in ovarian carcinoma than in benign tumors and normal ovary tissue (p<0.05) and was positively associated with dedifferentiation, FIGO staging and p-p70s6k expression of ovarian carcinoma (p<0.05).

CONCLUSIONS

The up-regulated RhoC expression may affect ovarian carcinogenesis and should be considered a good biomarker for the differentiation and progression of ovarian carcinoma. RhoC plays an important role in apoptosis by modulating the relevant genes and the phosphorylation of downstream p70s6k.

BTB/POZ domain-containing protein 7: epithelial-mesenchymal transition promoter and prognostic biomarker of hepatocellular carcinoma

Epithelial-mesenchymal transition (EMT) is a critical step in the metastasis of hepatocellular carcinoma (HCC). BTB/POZ domain-containing protein 7 (BTBD7) regulates EMT-associated proteins implicated in HCC progression. However, the role(s) of BTBD7 in HCC have not been identified. Using highly metastatic HCC HCCLM3 cells, immortalized L02 hepatocytes, metastatic HCC animal models, and three independent cohorts of HCC patient specimens, we aimed to determine the involvement of BTBD7 in HCC metastasis. We show that BTBD7 messenger RNA and protein was highly expressed in HCC cells and tumor tissues, with such expression being associated with: enhanced cell motility, venous invasion, and poor prognosis. BTBD7 promoted HCC angiogenesis and metastasis in vitro and in vivo, but did not influence cell proliferation or colony formation. BTBD7 enhancement of HCC invasion and EMT phenotype occurred through activation of a RhoC-Rock2-FAK-signaling pathway, resulting in matrix metalloproteinase-2/9 production and microvessel formation. Applying a predictive risk score model, Cox regression analysis revealed that high BTBD7 expression integrated with high microvessel density was a powerful independent predictive factor of HCC clinical outcome.

CONCLUSION

The present study identifies BTBD7 as a novel candidate prognostic factor and a potential therapeutic target of HCC. (HEPATOLOGY 2013; 57:2326-2337).

The MLK-related kinase (MRK) is a novel RhoC effector that mediates lysophosphatidic acid (LPA)-stimulated tumor cell invasion

The small GTPase RhoC is overexpressed in many invasive tumors and is essential for metastasis. Despite its high structural homology to RhoA, RhoC appears to perform functions that are different from those controlled by RhoA. The identity of the signaling components that are differentially regulated by these two GTPases is only beginning to emerge. Here, we show that the MAP3K protein MRK directly binds to the GTP-bound forms of both RhoA and RhoC in vitro. However, siRNA-mediated depletion of MRK in cells phenocopies depletion of RhoC, rather than that of RhoA. MRK depletion, like that of RhoC, inhibits LPA-stimulated cell invasion, while depletion of RhoA increases invasion. We also show that active MRK enhances LPA-stimulated invasion, further supporting a role for MRK in the regulation of invasion. Depletion of either RhoC or MRK causes sustained myosin light chain phosphorylation after LPA stimulation. In addition, activation of MRK causes a reduction in myosin light chain phosphorylation. In contrast, as expected, depletion of RhoA inhibits myosin light chain phosphorylation. We also present evidence that both RhoC and MRK are required for LPA-induced stimulation of the p38 and ERK MAP kinases. In conclusion, we have identified MRK as a novel RhoC effector that controls LPA-stimulated cell invasion at least in part by regulating myosin dynamics, ERK and p38.

Potential for statins in the chemoprevention and management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common, treatment-resistant malignancy with a complex molecular pathogenesis. Statins are a widely used class of cholesterol-lowering drugs with potential anticancer activity. We reviewed the evidence for a role of statins in primary and secondary chemoprevention of HCC and slowing the course of otherwise incurable primary or recurrent disease. A literature search (key words: Statins, hepatocellular carcinoma) conducted to this end, retrieved 119 references. Here we summarize the history, mechanism of action and cardiovascular use of statins and highlight that statins can affect several pathways implicated in the development of HCC. In vitro and animal studies provide strong evidence for a favorable effect of statins on HCC. However, evidence in humans is conflicting. We discuss in full detail the methodological strengths and pitfalls of published data including three cohort studies suggesting that the use of statins may protect from the development of HCC and of a single trial reporting increased survival in those with advanced HCC randomized to receive statins. A remarkably hepato-safe class of drugs acting on both hepatocyte and endothelial cells, statins also have potentially beneficial effects in lowering portal hypertension. In conclusion, there is strong experimental evidence that statins are beneficial in chemopreventing and slowing the growth of HCC. However, randomized controlled trials are necessary in order to investigate the role of statins in the chemoprevention of HCC and in slowing the course of otherwise incurable disease in humans.

Novel roles of Vmp1: inhibition metastasis and proliferation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most deadly human cancers because of its high incidence of metastasis. Despite extensive efforts, therapies against metastasis of HCC remain underdeveloped. Vacuole membrane protein 1 (Vmp1) was recently identified to be involved in cancer-relevant processes; however, its expression, clinical significance and biological function in HCC progression are still unknown. Therefore, we evaluated the expression of Vmp1 in human HCC specimens. To functionally characterize Vmp1 in HCC, we upregulated its expression in HCCLM3 cells using a plasmid transfection approach, following which both in vitro and in vivo models were used to elucidate its role. A significant downregulation of Vmp1 was found in human HCC tissues and closely correlated with multiple tumor nodes, absence of capsular formation, vein invasion and poor prognosis of HCC. Such expression was verified with HCC cell lines including HepG2, MHCC97-L and HCCLM3, and the Vmp1 expression levels negatively correlated with metastatic potential. Interestingly, upregulation of Vmp1 significantly affects proliferation, migration, invasion and adhesion of HCCLM3 cells. Using a mouse model, we demonstrated that upregulation of Vmp1 was associated with suppression of growth and pulmonary metastases of HCC. Therefore, our data suggest Vmp1 is a novel prognostic marker and potential therapeutic target for metastasis of HCC.

Formulation approaches to short interfering RNA and MicroRNA: challenges and implications

RNA interference has emerged as a potentially powerful tool in the treatment of genetic and acquired diseases by delivering short interfering RNA (siRNA) or microRNA (miRNA) to target genes, resulting in their silencing. However, many physicochemical and biological barriers have to be overcome to obtain efficient in vivo delivery of siRNA and miRNA molecules to the organ/tissue of interest, thereby enabling their effective clinical therapy. This review discusses the challenges associated with the use of siRNA and miRNA and describes the nonviral delivery strategies used in overcoming these barriers. More specifically, emphasis has been placed on those technologies that have progressed to clinical trials for both local and systemic siRNA and miRNA delivery.

GHGKHKNK octapeptide (P-5m) inhibits metastasis of HCCLM3 cell lines via regulation of MMP-2 expression in in vitro and in vivo studies

P-5m, an octapeptide derived from domain 5 of HKa, was initially found to inhibit the invasion and migration of melanoma cells. The high metastatic potential of melanoma cells was prevented by the HGK motif in the P-5m peptide in vitro and in an experimental lung metastasis model, suggesting that P-5m may play an important role in the regulation of tumor metastasis. The aim of this study was to measure the effect of P-5m on tumor metastasis of human hepatocarcinoma cell line (HCCLM3) in vitro and in vivo in a nude mouse model of hepatocellular carcinoma (HCC), and detect the mechanisms involved in P-5m-induced anti-metastasis. By gelatin zymography, matrix metallo-proteinases 2 (MMP-2) activity in HCCLM3 was dramatically diminished by P-5m peptide. In addition, the migration and metastasis of HCCLM3 cells was also inhibited by the peptide in vitro. In an orthotopic model of HCC in nude mice, P-5m treatment effectively reduced the lung metastasis as well as the expression of MMP-2 in the tumor tissues. Overall, these observations indicate an important role for P-5m peptide in HCC invasion and metastasis, at least partially through modulation MMP-2 expression. These data suggests that P-5m may have therapeutic potential in metastatic human hepatocarcinoma.

Tumor suppressor microRNA-493 decreases cell motility and migration ability in human bladder cancer cells by downregulating RhoC and FZD4

The purpose of this study was to identify new tumor suppressor microRNAs (miRNA; miR) in bladder cancer, conduct functional analysis of their suppressive role, and identify their specific target genes. To explore tumor suppressor miRs in bladder cancer, miR microarray was conducted using SV-HUC-1, T24, J82, and TCCSUP cells. Expression of miR-493 in bladder cancer (T24, J82, and TCCSUP) cells was downregulated compared with normal SV-HUC-1 cells. Also, the expression of miR-493 was significantly lower in bladder cancer tissues than in their corresponding noncancerous tissues. Transfection of miR-493 into T24 or J82 cells decreased their cell growth and migration abilities. On the basis of this result, to identify potential miR-493 target genes, we used target scan algorithms to identify target oncogenes related to invasion and migration. miR-493 decreased 3'-untranslated region luciferase activity and protein expression of FZD4 and RhoC. miR-493 also decreased binding of RhoC and Rock-1. miR-493 is a new tumor suppressor miRNA in bladder cancer and inhibits cell motility through downregulation of RhoC and FZD4.

Heat shock factor 1 promotes invasion and metastasis of hepatocellular carcinoma in vitro and in vivo

BACKGROUND

Heat shock factor 1 (HSF1) is a powerful, multifaceted modifier of carcinogenesis. However, the clinical significance and biologic function of HSF1 in hepatocellular carcinoma (HCC) remain unknown.

METHODS

Quantitative reverse transcriptase-polymerase chain reaction analysis, Western blot analysis, and immunohistochemical staining were used to detect expression levels of HSF1, and its correlation with clinicopathologic parameters and the prognosis for patients with HCC were analyzed. In addition, the biologic function and molecular mechanisms of HSF1 in HCC were investigated in vitro and in vivo.

RESULTS

HSF1 levels were elevated predominantly in HCC, especially in venous emboli from HCC (P < .05), and high expression levels of HSF1 were correlated significantly with multiple nodules, venous invasion, absence of capsular formation, and high Edmondson-Steiner grade as well as poor overall survival and disease-free survival in patients with HCC (P < .05). Multivariate Cox regression analysis revealed that high HSF1 expression was an independent prognostic factor for overall survival in patients with HCC (relative risk, 4.874; P < .001). Finally, HSF1 was capable of promoting HCC cell migration and invasion in vitro and in vivo by facilitating the expression and phosphorylation of heat shock protein 27.

CONCLUSIONS

Collectively, the current findings suggested that HSF1 may serve as a novel prognostic marker and therapeutic target for HCC.

RhoGDIα-dependent balance between RhoA and RhoC is a key regulator of cancer cell tumorigenesis

RhoGTPases are key signaling molecules regulating main cellular functions such as migration, proliferation, survival, and gene expression through interactions with various effectors. Within the RhoA-related subclass, RhoA and RhoC contribute to several steps of tumor growth, and the regulation of their expression affects cancer progression. Our aim is to investigate their respective contributions to the acquisition of an invasive phenotype by using models of reduced or forced expression. The silencing of RhoC, but not of RhoA, increased the expression of genes encoding tumor suppressors, such as nonsteroidal anti-inflammatory drug-activated gene 1 (NAG-1), and decreased migration and the anchorage-independent growth in vitro. In vivo, RhoC small interfering RNA (siRhoC) impaired tumor growth. Of interest, the simultaneous knockdown of RhoC and NAG-1 repressed most of the siRhoC-related effects, demonstrating the central role of NAG-1. In addition of being induced by RhoC silencing, NAG-1 was also largely up-regulated in cells overexpressing RhoA. The silencing of RhoGDP dissociation inhibitor α (RhoGDIα) and the overexpression of a RhoA mutant unable to bind RhoGDIα suggested that the effect of RhoC silencing is indirect and results from the up-regulation of the RhoA level through competition for RhoGDIα. This study demonstrates the dynamic balance inside the RhoGTPase network and illustrates its biological relevance in cancer progression.

FBI-1 promotes cell proliferation and enhances resistance to chemotherapy of hepatocellular carcinoma in vitro and in vivo

BACKGROUND

The so-called factor that binds to inducer of short transcripts-1 (FBI-1) purportedly plays an important role in tumorigenesis; however, its role in hepatocellular carcinoma (HCC) remains unknown. The objective of this study was to investigate the expression level, clinical relevance, and biologic function of FBI-1 in HCC.

METHODS

Real-time quantitative reverse transcriptase-polymerase chain reaction analysis, Western blot analysis, and immunohistochemical staining were used to detect expression levels of FBI-1 and to analyze its relation to clinicopathologic parameters and to the prognosis of patients with HCC. In addition, the biologic functions of FBI-1 in regulating cell proliferation, migration, and reaction to chemotherapy were detected by using HepG2 cells and SMMC-7721 cells; subsequently, the molecular mechanism of FBI-1 also was investigated. Finally, a xenograft mouse model was used to validate the observations obtained from in vitro studies.

RESULTS

Expression levels of FBI-1 messenger RNA and protein were elevated significantly in HCC tissues compared with adjacent nontumorous liver tissues (ANLTs). Increased FBI-1 expression was correlated with multiple tumor nodes, Edmondson-Steiner grade, and a poor prognosis in patients with HCC (P < .05). In vitro studies revealed that FBI-1 was capable of promoting cell proliferation (but not cell migration) by regulating the cell cycle regulation proteins p53, p21, and p27. In addition, FBI-1 could inhibit cell death induced by 5-fluorouracil or doxorubicin through suppressing the activation of p53. Consistent with the in vitro data, FBI-1 was capable of promoting cell proliferation and enhancing chemotherapy resistance of HCC in vivo.

CONCLUSIONS

The current findings indicated that FBI-1 plays an important role in HCC carcinogenesis and chemotherapy tolerance, and FBI-1 may served as a novel prognostic marker and therapeutic target for HCC.

Analysis of microRNA expression profiling identifies microRNA-503 regulates metastatic function in hepatocellular cancer cell

BACKGROUND AND OBJECTIVES

Metastasis of cancer is a complex process that involves multiple alterations. Recent evidence indicates that small non-protein coding RNA molecules (miRNAs) might be involved in cancer-related processes in humans. This study was to systematically investigate the differentially expressed miRNAs during metastasis in hepatocellular carcinoma (HCC) using microarray technology.

METHODS

The differentially expressed miRNAs between HCCLM3 and MHCC97-L, two HCC cell lines with differently metastatic potentials were displayed using microarray technology. The expression of miR-503 was verified by the real-time quantitative polymerase chain reaction. In addition, the lentivirus-delivered system for expressing miR-503 in HCCLM3 cells was employed to investigate whether miR-503 was involved in invasive phenotype of HCC cell.

RESULTS

Our study built a metastasis-related miRNAs expression profiling, which includes 327 miRNAs expressed differentially between HCCLM3 and MHCC97-L cell lines. Furthermore, expression of miR-503 by lentivirus-delivered system in HCCLM3 cell was established successfully. Our results showed that miR-503 induces a G1 arrest and decreased proliferation for HCCLM3 cell (P < 0.05). In addition, miR-503 inhibits migration and invasion of HCCLM3 cell in vitro (P < 0.05).

CONCLUSIONS

This study described a metastasis-related miRNAs expression profiling and revealed miR-503 regulating metastatic function in HCC cell.

N-terminal and C-terminal heparin-binding domain polypeptides derived from fibronectin reduce adhesion and invasion of liver cancer cells

Background

Fibronectin (FN) is known to be a large multifunction glycoprotein with binding sites for many substances, including N-terminal and C-terminal heparin-binding domains. We investigated the effects of highly purified rhFNHN29 and rhFNHC36 polypeptides originally cloned from the two heparin-binding domains on the adhesion and invasion of highly metastatic human hepatocellular carcinoma cells (MHCC97H) and analyzed the underlying mechanism involved.

Methods

The MHCC97H cells that adhered to FN in the presence of various concentrations of rhFNHN29 and rhFNHC36 polypeptides were stained with crystal violet and measured, and the effects of rhFNHN29 and rhFNHC36 on the invasion of the MHCC97H cells were then detected using the Matrigel invasion assay as well as a lung-metastasis mouse model. The expression level of integrins and focal adhesion kinase (FAK) phosphotyrosyl protein was examined by Western blot, and the activity of matrix metalloproteinases (MMPs) and activator protein 1 (AP-1) was analyzed by gelatin zymography and the electrophoretic mobility band-shift assay (EMSA), respectively.

Results

Both of the polypeptides rhFNHN29 and rhFNHC36 inhibited adhesion and invasion of MHCC97H cells; however, rhFNHC36 exhibited inhibition at a lower dose than rhFNHN29. These inhibitory effects were mediated by integrin αvβ3 and reversed by a protein tyrosine phosphatase inhibitor. Polypeptides rhFNHN29 and rhFNHC36 abrogated the tyrosine phosphorylation of focal adhesion kinase (p-FAK) and activation of activator protein 1 (AP-1), resulting in the decrease of integrin αv, β3 and β1 expression as well as the reduction of MMP-9 activity.

Conclusions

Polypeptides rhFNHN29 and rhFNHC36 could potentially be applicable to human liver cancer as anti-adhesive and anti-invasive agents.

Significance of RhoC mRNA expression in esophageal squamous cell carcinoma

AIM: To investigate the expression of RhoC mRNA in esophageal squamous cell carcinoma (ESCC) and to explore its correlation with the development and progression of ESCC.

METHODS: Semi-quantitative RT-PCR was used to detect the relative expression levels of RhoC mRNA in 62 ESCC specimens, 31 tumor-adjacent atypical hyperplastic epithelial specimens and 62 normal esophageal epithelial specimens. The distribution of RhoC transcripts in ESCC was determined by in situ hybridization.

RESULTS: The mRNA expression of RhoC was closely correlated with tumor grade, infiltration and lymph node metastasis in ESCC (all P < 0.05). The expression intensity of RhoC mRNA in carcinoma, adjacent atypical hyperplasia epithelium and normal esophageal epithelium were 0.902 ± 0.119, 0. 731 ± 0.065 and 0.653 ± 0.069, respectively, with a significant difference among the three groups (P < 0.01). In situ hybridization analysis demonstrated that RhoC transcripts were detected in the cytoplasm of cells. The positive rates of RhoC mRNA expression in carcinoma, tumor-adjacent atypical hyperplasia epithelium and normal esophageal epithelium were 80.6% (50/62), 32.3% (10/31) and 21.0% (13/62), respectively, with a significant difference among the three groups (P < 0.01). RT-PCR results were consistent with those obtained by in situ hybridization.

CONCLUSION: The mRNA expression of RhoC in ESCC increases significantly and is closely correlated with tumor biological behavior, which suggests that RhoC overexpression is closed associated with the pathogenesis of ESCC. RhoC may be a new auxiliary parameter for early diagnosis and prognostic prediction for ESCC.

RhoGTPases and Rho-effectors in hepatocellular carcinoma metastasis: ROCK N'Rho move it

Hepatocellular carcinoma (HCC) is an intractable disease with an extremely high mortality rate. Metastasis is the major factor of liver failure, tumour recurrence and death in HCC patients. Unfortunately, no promising curative therapy for HCC metastasis is available as yet; therefore, treatment for advanced HCC still remains a formidable challenge. A large body of evidence has demonstrated that the RhoGTPases/Rho-effector pathway plays important roles in mediating HCC metastasis based on their foremost functions in orchestrating the cell cytoskeletal reorganization. This review will first discuss the general principles of cancer metastasis and cancer cell movement with a particular focus on HCC.We will then summarize the implications of various members in the RhoGTPases/Rho-effectors signalling cascade including the upstream RhoGTPase regulators RhoGTPases and Rho-effectors and their downstream targets in HCC metastasis. Finally, we will discuss the therapeutic insight of targeting the RhoGTPases/Rho-effector pathway in HCC. Taken together, the literature demonstrates the importance of the RhoGTPases/Rho-effector signalling pathway in HCC metastasis and marks the necessity to have a more thorough knowledge of this complicated signalling network in order to develop novel therapeutic strategies for HCC patients.

Novel role for epidermal growth factor-like domain 7 in metastasis of human hepatocellular carcinoma

Epidermal growth factor-like domain 7 (Egfl7) is a recently identified secreted protein that is believed to be primarily expressed in endothelial cells (ECs). Although its expression was reported elevated during tumorigenesis, whether and how Egfl7 contributes to human malignancies remains unknown. In the present study overexpression of Egfl7 was found predominantly in hepatocellular carcinoma (HCC) cells in HCC tissues and closely correlated with poor prognosis of HCC. The expression of Egfl7 in cancer cells was further verified with HCC cell lines including HepG2, MHCC97-L, and HCCLM3, and the Egfl7 expression levels positively correlated with metastatic potential of HCC cell lines was tested. To functionally characterize Egfl7 in HCC, we depleted its expression in HCCLM3 cells by using small interfering RNA. Interestingly, reduction of Egfl7 expression resulted in significant inhibition of migration but not growth of HCCLM3 cells. Biochemical analysis indicated that Egfl7 could facilitate the phosphorylation of focal adhesion kinase (FAK) and therefore promote the migration of HCCLM3 cells. In addition, this effect was almost completely blocked by inhibition of epidermal growth factor receptor (EGFR), indicating that the activation of FAK by Egfl7 is mediated through EGFR. Finally, we used a mouse model to demonstrate that down-regulation of Egfl7 was associated with suppression of intrahepatic and pulmonary metastases of HCC. Collectively, our study shows for the first time that overexpression of Egfl7 in HCC and Egfl7 promotes metastasis of HCC by enhancing cell motility through EGFR-dependent FAK phosphorylation.

CONCLUSION

Our study suggests Egfl7 as a novel prognostic marker for metastasis of HCC and a potential therapeutic target.

Autotaxin

Autotaxin is a protein of approximately 900 amino acids discovered in the early 1990s. Over the past 15 years, a strong association between cancer cells and autotaxin production has been observed. Recent publications indicate that autotaxin and the capacity of cancer to metastasise are intimately linked. The discovery of new molecular targets in pharmacology is a mixture of pure luck, hard work and industrial strategy. Despite a crucial and desperate need for new therapeutic tools, many targets are approached in oncology, but only a few are validated and end up at the patient bed. Outside the busy domain of kinases, few targets have been discovered that can be useful in treating cancer, particularly metastatic processes. The fortuitous relationship between autotaxin and lysophosphatidic acid renders the results of observations made in the diabetes/obesity context considerably important. The literature provides observations that may aid in redesigning experiments to validate autotaxin as a potential oncology target.

Rho GTPase function in tumorigenesis

Malignant tumor cells display uncontrolled proliferation, loss of epithelial cell polarity, altered interactions with neighboring cells and the surrounding extracellular matrix, and enhanced migratory properties. Proteins of the Rho GTPase family regulate all these processes in cell culture and, for that reason, Rho GTPases, their regulators, and their effectors have been suggested to control tumor formation and progression in humans. However, while the tumor-relevant functions of Rho GTPases are very well documented in vitro, we are only now beginning to assess their contribution to cancer in human patients and in animal models. This review will give a very brief overview of Rho GTPase function in general and then focus on in vivo evidence for a role of Rho GTPases in malignant tumors, both in human patients and in genetically modified mice.