Cyclodextrin-mediated formation of porous RNA nanospheres and their application in synergistic targeted therapeutics of hepatocellular carcinoma.

Spherical and porous nanoparticles are ideal nanostructures for drug delivery. But currently they are mainly composed of non-degradable inorganic materials, which hinder clinical applications. Here, biological porous nanospheres using RNA as the building blocks and cyclodextrin as the adhesive were synthesized. The RNA contained the aptamer of EpCAM for targeting delivery and siRNA for gene silencing of EpCAM, while cyclodextrin could load insoluble sorafenib, the core drug of targeted therapy for hepatocellular carcinoma (HCC), through its hydrophobic cavity. After being internalized into targeted HCC cells under the assistance of the aptamer, the porous nanospheres could be degraded by the cytoplasmic Dicer enzymes, releasing siRNA and sorafenib for synergistic therapy. The synergistic efficacy of the porous RNA nanospheres has been validated at in vitro function assay, subcutaneous tumor bearing mice, and orthotopic tumor bearing mice in vivo models. In view of the broad prospects of synergy of gene therapy with chemotherapy, and the fact that RNA and cyclodextrin of the porous nanospheres can be extended to load various types of siRNA and small molecule drugs, respectively, this form of biological porous nanospheres offers opportunities for targeted delivery of suitable drugs for treatment of specific tumors.

Correction: Upregulation of SNX5 predicts poor prognosis and promotes hepatocellular carcinoma progression by modulating the EGFR-ERK1/2 signaling pathway.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A new risk model comprising genes highly correlated with CD133 identifies different tumor-immune microenvironment subtypes impacting prognosis in hepatocellular carcinoma.

The existence of cancer stem cells (CSCs), marked by CD133, is the primary cause of death in hepatocellular carcinoma (HCC). Here, we generated a new risk model comprising the signatures of four genes highly correlated with CD133 (CD133(hi)) that help improve survival in HCC. Three datasets were used to identify the differential CD133(hi) genes by comparing sorted CD133+ liver CSCs and CD133- differentiated counterparts. Univariate analysis was used to screen significantly differential CD133(hi) genes associated with overall survival in the training dataset, which were used for risk model construction. High-risk patients were strongly associated with poor survival by Kaplan-Meier survival analysis in both the training and validation datasets. Clinical stratification analyses further demonstrated that the risk factors acted as independent factors and that high-risk patients were characterized by more aggressive cancer features. Functional enrichment analyses performed by gene set enrichment analysis (GSEA) and the Database for Annotation, Visualization and Integrated Discovery (DAVID) revealed that high-risk patients showed the disturbance of immune hepatic homeostasis involving aberrant immune cells, including macrophages and T and B cells, and an abnormal inflammatory response including the IL6/Jak/STAT3 pathway and TNF signaling pathway. In conclusion, our constructed CD133(hi) gene risk model provides a resource for understanding the role of CD133+ CSCs in the progression of HCC in terms of tumor-immune interactions.

TBX2 Identified as a Potential Predictor of Bone Metastasis in Lung Adenocarcinoma via Integrated Bioinformatics Analyses and Verification of Functional Assay.

Objective: Bone metastasis from patients with advanced lung adenocarcinoma (LAC) is a very serious complication. To better understand the molecular mechanism, our current study sheds light on identification of hub genes mediating bone metastatic spread by combining bioinformatic analysis with functional verification. Methods: First, we downloaded a lung adenocarcinoma dataset (GSE76194) from Gene Expression Omnibus, analyzed differentially expressed genes (DEGs) through Limma package in R software and constructed a protein-protein interaction network. Based on that preliminary data, we further performed modular and topological analysis using Cystoscope to obtain biological connected genes. Through literature searching and performing mRNA expression analysis on the other independent public dataset (GSE10799), we finally focused on TBX2. Functional effects of TBX2 were performed in tumorigenicity assays including migration and invasion assays, cell proliferation assay, and cell cycle assay. In addition, mechanically, we found enriched pathways related to bone metastasis using Gene Set Enrichment Analysis (GSEA) and validated our results by western blot. Result: A total of 1132 significant genes were sorted initially. We selected common significant genes (log FC>2; p<0.01) from both the biological network data and microarray data. In total, 44 such genes were identified. we found TBX2, along with 10 other genes, to be reported with relevance to bone metastasis in other cancer types. Moreover, TBX2 showed significantly higher expression levels in patients that were found positive for metastasis to bone marrow compared to patients that did not exhibit this type of metastasis in the other separated cohort (GSE10799). Thus, we finally focused on TBX2. We found that TBX2 had detectable expression in LAC cell lines and silencing endogenous TBX2 expression in A549 and H1299 cell lines markedly suppressed migration and invasion, cell proliferation and arrested cell-cycle. Pathway enrichment analyses suggested that TBX2 drove LAC oncogenesis and metastasis through various pathways with epithelial mesenchymal transition (EMT) figuring prominently in the bone metastatic group, which was evidenced by western blot. Conclusion: Collectively, TBX2 plays as a potential predictor of bone metastasis from LAC, yielding a better promise view towards "driver" gene responsible for bone metastasis.

Upregulation of SNX5 predicts poor prognosis and promotes hepatocellular carcinoma progression by modulating the EGFR-ERK1/2 signaling pathway.

Endocytosis is an essential component of cell motility, which facilitates the malignant behavior of cancer. Sorting nexin (SNX) family members are associated with tumor progression. However, the role and mechanism of SNX5 in hepatocellular carcinoma (HCC) progression remain largely unknown. In this study, we investigated the clinical significance and possible involvement of SNX5 in the progression of HCC. Here, we showed that SNX5 was upregulated in tumors compared with adjacent nontumorous tissues in HCC patients. The upregulation of SNX5 in HCC was associated with vascular invasion, intrahepatic metastasis, and poor prognosis. The overexpression of SNX5 promoted HCC cell proliferation, migration, invasion, and metastasis, whereas silencing SNX5 expression resulted in decreased cell proliferation, migration, and invasion. Knockdown of SNX5 significantly inhibited HCC cell proliferation by inducing G1/S transition arrest. Mechanistically, we demonstrated that SNX5 promoted cell proliferation, migration, and invasion via the activation of the EGFR-ERK1/2 pathway by blocking EGF-mediated EGFR internalization. We found that SNX5 interacted with EGFR in HCC cells. Moreover, SNX5-induced cell proliferation, migration, and invasion were partially reversed by the knockdown of EGFR or by ERK1/2 inhibitors. In addition, we demonstrated that SNX5 knockdown sensitized HCC cells to tyrosine kinase inhibitors, including erlotinib and sorafenib. Taken together, our results indicate that SNX5 promotes HCC cell proliferation and metastasis via inhibiting the endocytosis and degradation of EGFR, thereby activating the ERK1/2 signaling pathway. Our work also suggests that SNX5 is a potential therapeutic target for HCC.

RNA-binding protein KHSRP promotes tumor growth and metastasis in non-small cell lung cancer.

BACKGROUND: KH-type splicing regulatory protein (KHSRP) plays an important role in cancer invasion, but the relevant mechanism is not well known. In the present study, we investigated the function and potential molecular mechanism of KHSRP in non-small cell lung cancer (NSCLC) metastasis and elucidated its clinical significance. METHODS: Isobaric tags for relative and absolute quantitation and the SWATH™ approach were combined with nanoliquid chromatography-tandem mass spectrometry analysis to identify metastasis-associated nucleoproteins in NSCLC. Real-time PCR and Western blot were used to screen for metastasis-associated candidate molecules. Gene knockdown and overexpression were used to investigate their functions and molecular mechanisms in lung cancer cells. Coimmunoprecipitation (Co-IP) experiments were performed to identify the interactions between candidate molecules and their interacting proteins. Gene expression and its association with multiple clinicopathologic characteristics were analyzed by immunohistochemistry (IHC) and Western blot in human lung cancer specimens. RESULTS: KHSRP was identified as a metastasis-associated candidate molecule. In NSCLC cell lines, knockdown of KHSRP significantly reduced lung cancer cell proliferation, migration, and invasion in vitro and in vivo, whereas overexpression of KHSRP did the opposite. Mechanistically, the protein heterogeneous nuclear ribonucleoprotein C (C1/C2) (HNRNPC) was identified to interact with KHSRP using Co-IP experiments. In NSCLC cell lines, overexpression of HNRNPC significantly promoted lung cancer cell proliferation, migration, and invasion in vitro and in vivo. KHSRP and HNRNPC may induce human lung cancer cell invasion and metastasis by activating the IFN-α-JAK-STAT1 signaling pathway. Drastically higher expression levels of KHSRP and HNRNPC were observed in lung cancer tissues compared to those in adjacent noncancerous tissues. Increased KHSRP and HNRNPC expression was significantly associated with advanced tumor stages and metastasis (both lymph node and distant). Kaplan-Meier survival analysis showed that patients with high KHSRP and HNRNPC expression levels were predicted to have the shortest survival times and to have a poor prognosis. CONCLUSIONS: KHSRP plays an important role in NSCLC metastasis and may serve as a potential prognostic marker and novel therapeutic target for lung cancer metastasis treatment.

HIF-1α-induced RIT1 promotes liver cancer growth and metastasis and its deficiency increases sensitivity to sorafenib.

Ras-like-without-CAAX-1 (RIT1) belongs to the RAS superfamily of small GTPases, which plays critical roles in tumor progression. However, little is known about the roles of RIT1 in hepatocellular carcinoma (HCC). Here we found that RIT1 expression was positively associated with the presence of intrahepatic metastasis and the histological grade of HCC and higher RIT1 expression indicated shorter overall survival in HCC patients. In vitro and in vivo studies revealed that RIT1 functioned as an oncogene, as overexpression of RIT1 enhanced HCC cell proliferation and aggressive behavior, whereas silencing RIT1 expression repressed the malignant behaviors. Furthermore, RIT1 deficiency increased drug sensitivity to sorafenib treatment. We further demonstrated that hypoxia-inducible factor 1α (HIF-1α) directly transcriptionally upregulated RIT1, and its stableness was positively correlated with RIT1 expression in HCC tissues. Knockdown of RIT1 attenuated the invasion and migration induced by hypoxia. Collectively, our data highlight the significance of HIF-1α/RIT1 axis in driving HCC progression and sorafenib resistance.

OTUB2 stabilizes U2AF2 to promote the Warburg effect and tumorigenesis via the AKT/mTOR signaling pathway in non-small cell lung cancer.

Increasing evidence has confirmed that deubiquitinating enzymes play an important role in lung cancer progression. In the current study, we investigated the expression profile of deubiquitinating enzymes in non-small cell lung cancer (NSCLC) tissues and identified OTUB2 as an upregulated deubiquitinating enzyme. The role of OTUB2 in NSCLC is unknown. Methods: Quantitative, real-time PCR and Western blot were used to detect OTUB2 and U2AF2 expression in NSCLC tissues. The correlations between OTUB2 and U2AF2 expression and clinicopathologic features were then analyzed. We used In vitro Cell Counting Kit-8 (CCK-8) , colony formation , and trans-well invasion assays to investigate the function of OTUB2 and U2AF2 in tumorigenesis. The regulation of glycolysis by OTUB2 and U2AF2 was assessed by determining the extracellular acid ratio, glucose consumption, and lactate production. The mechanism of OTUB2 was explored through co-immunoprecipitation and mass spectrometry analyses. A xenograft model was also used to study the tumorigenesis role of OTUB2 In vivo. Results: OTUB2 expression was significantly upregulated in primary NSCLC tissues and greatly associated with metastasis, advanced tumor stages, poor survival, and recurrence. In NSCLC cell lines, OTUB2 promoted cell growth, colony formation, migration, and invasive activities. Mechanistic investigations showed that OTUB2 stimulated the Warburg effect and induced the activation of the serine/threonine kinase/mechanistic target of rapamycin kinase (AKT/mTOR) pathway in different NSCLC cells. More importantly, OTUB2 promoted NSCLC progression, which was largely dependent on the direct binding to and deubiquitination of U2AF2, at least in NSCLC cells. U2AF2 expression was also significantly upregulated in primary NSCLC tissues and dramatically associated with metastasis, advanced tumor stages, poor survival, and recurrence. Importantly, a positive correlation between the protein expression of OTUB2 and U2AF2 in NSCLC tissues was found. In vivo experiments indicated that OTUB2 promoted xenograft tumor growth of NSCLC cell. In addition, our results suggest that high expression of OTUB2, U2AF2 and PGK1 is significantly associated with worse prognosis in NSCLC patients. Conclusion: Taken together, the present study provides the first evidence that OTUB2 acts as a pivotal driver in NSCLC tumorigenesis by stabilizing U2AF2 and activating the AKT/mTOR pathway and the Warburg effect. It may serve as a new potential prognostic indicator and therapeutic target in NSCLC.

DCUN1D1 facilitates tumor metastasis by activating FAK signaling and up-regulates PD-L1 in non-small-cell lung cancer.

E3 ubiquitin ligases, which are key enzymes in the ubiquitin proteasome system, catalyze the ubiquitination of proteins to target them for proteasomal degradation. Emerging evidence suggests that E3 ubiquitin ligases play important roles in the development and progression of lung cancer. In our study, we characterized the gene expression landscape of lung cancer using data obtained from TCGA to explore the changes in E3 ubiquitin ligase containing the regulators of E3 ubiquitin ligase activity. Overall, most gene expression changes occurred in NSCLC tissues compared with adjacent normal ones. In total, 48 E3 ubiquitin ligases containing the regulators were up-regulated in NSCLC tissues compared with their levels in normal tissues. We analyzed the expression of up-regulated E3 ubiquitin ligases containing the regulators in two publicly available transcriptome data sets (GSE13213 and GSE30219). We found that four E3 ubiquitin ligases (UHRF1, BRCA1, TRAIP and HLTF) and one regulator of ubiquitin E3 activity DCUN1D1 that were dramatically up-regulated in cancer were significantly associated with tumor metastasis and patient's poor prognosis both in two transcriptome data sets. Next, clinical analysis indicated that the expression levels of DCUN1D1 correlated with clinical stage and lymph node metastasis in NSCLC patients as determined by quantitative reverse transcription-PCR. Furthermore, functional assays showed that DCUN1D1 promoted NSCLC cell invasion and migration as determined by transwell assay in vitro. Mechanistically, we found that the C-terminal Cullin binding domain leads to oncogenic activity and the UBA domain acts as a negative regulator of DCUN1D1 function in NSCLC. Moreover, DCUN1D1 activated the FAK oncogenic signaling pathway and up-regulated PD-L1. Taken together, our results demonstrate that DCUN1D1 is a metastasis regulator and suggest a new therapeutic option for NSCLC metastasis.

Downregulation of AZGP1 by Ikaros and histone deacetylase promotes tumor progression through the PTEN/Akt and CD44s pathways in hepatocellular carcinoma.

Increasing evidence has shown that zinc-alpha2-glycoprotein (AZGP1) is associated with the progression and prognosis of several tumor types. However, little is known regarding the underlying molecular mechanisms of AZGP1 in hepatocellular carcinoma (HCC). In this study, we report that transcription factor Ikaros bound to the AZGP1 promoter and increased its expression in HCC cells. The downregulation of AZGP1 was associated with histone deacetylation in HCC. In addition, the positive feedback regulation via acetylation of histone H4-mediated transactivation of the Ikaros promoter and the Ikaros-mediated transactivation of the acetylation of histone H4 were crucial for regulating AZGP1 expression in HCC cells. Moreover, low serum AZGP1 level in HCC patients was associated with poor prognosis. The ectopic overexpression of AZGP1 or recombinant AZGP1 protein inhibited HCC cell proliferation, migration and invasion in vitro and in vivo, whereas silencing AZGP1 expression resulted in increased cell proliferation, migration and invasion in vitro. In addition, we found that AZGP1 inhibited cell migration and invasion through the regulation of the PTEN/Akt and CD44s pathways. Collectively, our findings revealed the molecular mechanism of AZGP1 expression in HCC, providing new insights into the mechanisms underlying tumor progression.

MicroRNA-148a Suppresses Invasion and Metastasis of Human Non-Small-Cell Lung Cancer.

BACKGROUND/AIMS: microRNAs (miRNAs) are noncoding RNAs that regulate multiple targets through either the degradation of mRNAs or the inhibition of protein translation, thereby altering several functions simultaneously. Growing evidence indicates that miRNAs are involved in carcinogenesis and tumor progression in non-small-cell lung cancer (NSCLC). METHODS: In this study, the mRNA expression levels of miR-148a were examined in NSCLC cell lines and patient specimens using quantitative reverse transcription-PCR. The functions of miR-148a in migration/invasion and lung metastasis formation were determined by using transwell and tail vein injection assays, respectively. RESULTS: We demonstrated that miR-148a was down-regulated in NSCLC metastatic samples, and its expression was suppressed in NSCLC compared with the corresponding nonmalignant lung tissues. Clinical analysis indicated that miR-148a expression was lower in NSCLC patients compared with nonmalignant lung tissues . Decreased miR-148a was significantly associated with tumor node metastasis stage and lymph node metastasis. Furthermore, functional assays showed that miR-148a expression suppressed NSCLC cell invasive and migratory abilities in vitro and suppressed cancer metastasis in vivo, while inhibition of miR-148a enhanced NSCLC cell invasion and lung metastasis formation in a mouse model. CONCLUSIONS: Evidence from this study demonstrated that miR-148a exerts tumor-suppressive effects in NSCLC and suggests a new therapeutic option for NSCLC.

Establishment of a highly metastatic model with a newly isolated lung adenocarcinoma cell line.

Lung cancer is the leading cause of malignancy-related death worldwide, and metastasis always results in a poor prognosis. However, therapeutic progress is hampered by a deficiency of appropriate pre-clinical metastatic models. To bridge this experimental gap, we developed an in vivo metastatic model via subcutaneous (s.c.) injection. The original cell line (XL-2) adopted in this model was newly isolated from the ascites of a patient with extensive metastases of lung adenocarcinoma, thereby avoiding any alteration of its initial molecular biology features from artificial serial cultivation. After comprehensive phenotypical and histological analysis, it was identified as a lung adenocarcinoma cell line. Additionally, the drug test showed that XL-2 cell line was sensitive to docetaxel, and resistant to doxorubicin, indicating it might serve as a cell line model of drug resistance for identifying mechanisms of tumors resistant to doxorubicin. Through this s.c. model, we further obtained a highly metastatic cell line (designated XL-2sci). The metastatic rate of mice in XL-2 group was 3/10, in contrast to the rate of 9/10 in XL-2sci group. Optical imaging, micro-computed tomography (micro-CT) scanning and Transwell assays were further applied to identify the enhanced metastatic capacity of Xl-2sci cells both in vivo and in vitro. Compared with XL-2 cells, ITRAQ labeled proteomics profiling study showed that some tumor metastasis-associated proteins were upregulated in XL-2sci cells, which also indicated the reliability of our model. Proliferation ability of XL-2 and XL-2sci were also evaluated. Results showed that highly metastatic XL-2sci possessed a decreased proliferation capacity versus XL-2, which demonstrated that its increased metastatic activity was not facilitated by a faster growth rate. In conclusion, we successfully developed an in vivo metastatic model using a newly established lung adenocarcinoma cell line, which will be beneficial to further investigations of lung cancer metastasis and to the development of anti-metastasis drugs.

Quantitative proteomic analysis of the metastasis-inhibitory mechanism of miR-193a-3p in non-small cell lung cancer.

BACKGROUND: microRNAs can repress the expression of target genes by destabilizing their mRNAs or by inhibiting their translation. Our previous findings suggested that miR-193a-3p inhibited the progression of NSCLC both in vitro and in vivo. However, the biological processes and molecular pathways through which this miRNA exerts its positive effects are unknown. METHODS: To explore the molecular mechanisms by which miR-193a-3p inhibited NSCLC metastasis, we investigated the changes in the protein profile of SPC-A-1sci (highly metastatic) cells in response to the up-regulation of miR-193a-3p expression using a proteomics approach (iTRAQ combined with NanoLC-MS/MS). Changes in the profiles of the expressed proteins were verified using western blotting and were analyzed using the DAVID and STRING programs. RESULTS: In the two replicated experiments, 4962/4946 proteins were identified, and the levels of expression of 4923/4902 proteins were quantified. In total, 112 of these proteins were differentially expressed. Among them, the up-regulated levels of expression of two of the 62 proteins with up-regulated expression (PPP2R2A and GSN) and the down-regulated levels of expression four of the 50 proteins with down-regulated expression (LMNB2, UHRF1, G3BP1, and HNRNPU) were verified using western blotting. The bioinformatics analysis revealed the interactions and signaling networks of these differentially expressed proteins. CONCLUSION: miR-193a-3p inhibited the metastasis of lung cancer cells by deregulating the expression of tumor-related proteins. These findings may improve the understanding of the molecular mechanisms underlying the metastatic-inhibitory effect of miR-193a-3p on lung cancer cells.

Inhibitory effects of transcription factor Ikaros on the expression of liver cancer stem cell marker CD133 in hepatocellular carcinoma.

CD133 is a cellular surface glycoprotein that has been reported as a marker for the enrichment of cancer stem cells (CSCs). However, the regulatory mechanism of CD133 remains unknown. CSCs have been proposed to contribute to radioresistance and multi-drug resistance. The elucidation of key regulators of CD133 and CSCs is critical for the development of CSC-targeted therapy. In this study, we showed that Ikarosinhibited the expression of CD133 via direct binding to the CD133 P1 promoter and repressed the tumorigenic and self-renewal capacity of CD133(+) cancer stem-like cells in hepatocellular carcinoma (HCC). We found that Ikaros interacted with CtBP as a transcription repressor complex, which inhibited CD133 expression in HCC. We also demonstrated that Ikaros expression was up-regulated by ETS1 which activity was regulated by MAPKs pathway. Furthermore, decreased expression of Ikaroswas significantly associated with poor survival in HCC patients. Overall, our study identifies that Ikaros plays a role as a transcription repressor in HCC and is a new reactivated therapeutic target for the treatment of HCC. Meanwhile, our findings provide evidence that Ikaros could be an attractive inhibitor of the target gene CD133, which reactivates anticancer mechanisms in targeted CSC therapy.

[Establishing the nude mice bone metastasis model of lung adenocarcinoma and applying MicroCT into the observation].

BACKGROUND AND OBJECTIVE: 50%-70% of patients with advanced lung cancer will develop bone metastases. The aim of this study is to establish the nude mice bone metastasis model of lung adenocarcinoma using A549, H1299, SPC-A-1 and XL-2, all of which own different invasion and migration abilities in vitro and supervise the bone metastases by MicroCT. METHODS: fifty BALB/C-nu/nu nude mice were grouped into five groups on average randomly. Cells of the four cell lines were injected into the left cardiac ventricle of mice in the four experimental groups (0.2 mL/mouse) respectively; meanwhile, mice in the control group were injected with normal saline (0.2 mL/mouse) in the same manner. Periodical radiological examination was carried out to supervise the variation of the mice since the second week after injection. When mice in each group became thin obviously, end the experiment of this group. Before the end, pathological sections of bone tissues were made. We classified the bone metastatic sites into axial skeleton and limb bone, in order to compare the metastatic rates of these two different parts. The bone metastatic abilities of the four cell lines was statistically analyzed by comparing the average time cost in the appearance of bone metastases and the percentage of bone metastases among the experimental groups. RESULTS: Different metastatic sites which had been identified both by MicroCT and pathological sections appeared in each group of the four experimental groups. By contrast, no metastasis was observed in the control group. The percentage of cancer metastasizing to axial skeleton was remarkably higher than the percentage of tumor metastasizing to the limb bone in each experimental group, which was consistent with the clinical regularity and characteristics of skeletal metastases with lung cancer. Thus, the model has been established triumphantly. However, there were no statistical differences in the average time consumed and skeletal metastatic rate among the four experimental groups. CONCLUSIONS: The disruption in the bone can be clearly detected by MicroCT, which is benefit to supervise the osseous metastasis. We successfully developed the nude mice bone metastasis model of lung adenocarcinoma, which will pave the way for exploring novel prevention and therapy strategies clinically. The four cell lines varied in invasion and migration abilities in vitro, but there was no statistical difference in the metastatic ability in vivo, and the reason need to be explored further in future.

G protein-coupled receptor 87 (GPR87) promotes the growth and metastasis of CD133⁺ cancer stem-like cells in hepatocellular carcinoma.

UNLABELLED: Hepatocellular carcinoma (HCC) is a prevalent disease worldwide, and the majority of HCC-related deaths occur due to local invasion and distant metastasis. Cancer stem cells (CSCs) are a small subpopulation of cancer cells that have been hypothesized to be responsible for metastatic disease. Recently, we and others have identified a CSC population from human HCC cell lines and xenograft tumors characterized by their expression of CD133. However, the precise molecular mechanisms by which CD133(+) cancer stem-like cells mediate HCC metastasis have not been sufficiently analyzed. Here, we have sorted HCC cells using CD133 as a cancer stem cell (CSC) marker by magnetic-activated cell sorting (MACS) and demonstrated that the CD133(+) HCC cells not only possess greater migratory and invasive capacity in vitro but are also endowed with enhanced metastatic capacity in vivo and in human HCC specimens when compared to CD133(-) HCC cells. Gene expression analysis of the CD133(+) and CD133(-) cells of the HCC line SMMC-7721 revealed that G protein-coupled receptor 87 (GPR87) is highly expressed in CD133(+) HCC cells. In this study, we explored the role of GPR87 in the regulation of CD133 expression. We demonstrated that the overexpression of GPR87 up-regulated CD133 expression, promoted CSC-associated migratory and invasive properties in vitro, and increased tumor initiation in vivo. Conversely, silencing of GPR87 expression reduced the levels of CD133 expression. CONCLUSION: GPR87 promotes the growth and metastasis of CD133(+) cancer stem-like cells, and our findings may reveal new targets for HCC prevention or therapy.

Hypoxia-inducible factor 1 alpha-activated angiopoietin-like protein 4 contributes to tumor metastasis via vascular cell adhesion molecule-1/integrin ß1 signaling in human hepatocellular carcinoma.

UNLABELLED: Angiopoietin-like protein 4 (ANGPTL4) plays complex and often contradictory roles in vascular biology and tumor metastasis, but little is known about its function in hepatocellular carcinoma (HCC) metastasis. In the present study, we showed that hypoxia-inducible factor 1α (HIF-1α) directly up-regulates ANGPTL4, and its stableness positively correlates with ANGPTL4 expression in HCC tissue. Overexpression of ANGPTL4 significantly increased HCC cell transendothelial migration in vitro and intrahepatic and distal pulmonary metastasis in vivo, whereas silencing ANGPTL4 expression or treatment with a neutralizing antibody specific for ANGPTL4 protein resulted in a reduced transendothelial migration. We also found that serum ANGPTL4 is higher in HCC patients, compared to healthy control, and correlates with intrahepatic metastasis and histological grade. Further, secreted ANGPTL4 promotes transendothelial migration and metastasis of HCC cells in vitro and in vivo through the up-regulation of vascular cell adhesion molecule-1 (VCAM-1) of human umbilical vein endothelial cells and the activation of the VCAM-1/integrin ß1 axis. CONCLUSION: ANGPTL4 is a target gene of HIF-1α and acts as an important regulator in the metastasis of HCC. Serum ANGPTL4 correlates with tumor progression and metastasis and might be used to indicate prognosis in HCC patients.

TC21 promotes cell motility and metastasis by regulating the expression of E-cadherin and N-cadherin in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is an aggressive type of cancer, and it may be at an advanced stage when it is detected. It has been shown that TC21, a member of the Ras superfamily, is associated with the proliferation, migration and transformation of tumor cells. Previous studies have shown that TC21 is overexpressed in breast, esophageal and oral carcinomas, and that it is closely associated with the early stages of tumorigenesis. In this study, we demonstrate that TC21 overexpression promotes the motility of HCC cells in vitro and intrahepatic metastasis in vivo. Furthermore, experiments examining the effects of both the ectopic expression of TC21 and siRNA treatment in HCC cells showed that TC21 alters the expression of the adhesive molecules E-cadherin and N-cadherin. Our data suggest that TC21 is associated with tumor progression and poor prognosis in HCC.