A decade's studies on metastasis of hepatocellular carcinoma

In-depth analysis of secretome and N-glycosecretome of human hepatocellular carcinoma metastatic cell lines shed light on metastasis correlated proteins

Cancer cell metastasis is a major cause of cancer fatality. But the underlying molecular mechanisms remain incompletely understood, which results in the lack of efficient diagnosis, therapy and prevention approaches. Here, we report a systematic study on the secretory proteins (secretome) and secretory N-glycoproteins (N-glycosecretome) of four human hepatocellular carcinoma (HCC) cell lines with different metastatic potential, to explore the molecular mechanism of metastasis and supply the clues for effective measurement of diagnosis and therapy. Totally, 6242 unique gene products (GPs) and 1637 unique N-glycosites from 635 GPs were confidently identified. About 4000 GPs on average were quantified in each of the cell lines, 1156 of which show differential expression (p<0.05). Ninety-nine percentage of the significantly altered proteins were secretory proteins and proteins correlated to cell movement were significantly activated with the increasing of metastatic potential of the cell lines. Twenty-three GPs increased both in the secretome and the N-glycosecretome were chosen as candidates and verified by western blot analysis, and 10 of them were chosen for immunohistochemistry (IHC) analysis. The cumulative survival rates of the patients with candidate (FAT1, DKK3) suggested that these proteins might be used as biomarkers for HCC diagnosis. In addition, a comparative analysis with the published core human plasma database (1754 GPs) revealed that there were 182 proteins not presented in the human plasma database but identified by our studies, some of which were selected and verified successfully by western blotting in human plasma.

Heat shock proteins in hepatocellular carcinoma: Molecular mechanism and therapeutic potential

Heat shock proteins (HSPs) are highly conserved proteins, which are expressed at low levels under normal conditions, but significantly induced in response to cellular stresses. As molecular chaperones, HSPs play crucial roles in protein homeostasis, apoptosis, invasion and cellular signaling transduction. The induction of HSPs is an important part of heat shock response, which could help cancer cells to adapt to stress conditions. Because of the constant stress condition in tumor microenvironment, HSPs overexpression is widely reported in many human cancers. In light of the significance of HSPs for cancer cells to survive and obtain invasive phenotype under stress condition, HSPs are often associated with poor prognosis and treatment resistance in many types of human cancers. It has been described that upregulation of HSPs may serve as diagnostic and prognostic markers in hepatocellular carcinoma (HCC). Targeting HSPs with specific inhibitor alone or in combination with chemotherapy regimens holds promise for the improvement of outcomes for HCC patients. In this review, we summarize the expression profiles, functions and molecular mechanisms of HSPs (HSP27, HSP70 and HSP90) as well as a HSP-like protein (clusterin) in HCC. In addition, we address progression and challenges in targeting these HSPs as novel therapeutic strategies in HCC.

Upregulation of long non coding RNA PCAT-1 contributes to cell proliferation, migration and apoptosis in hepatocellular carcinoma

Long non-coding RNAs (lncRNAs) exert regulatory functions on various biological processes in cancer cells, including proliferation, apoptosis and mobility. Prostate cancer-associated transcript 1 (PCAT-1) is a novel lncRNA that promotes cell proliferation in prostate cancer, however, the effect of PCAT‑1 in hepatocellular carcinoma (HCC) remains to be elucidated. The present study hypothesized that PCAT‑1 also exerts an important effect in HCC. The current study investigated PCAT-1 expression levels in HCC tissue samples and HepG2 and Bel‑7402 cell lines using the reverse transcription-quantitative polymerase chain reaction. The results demonstrated that PCAT-1 was upregulated in HCC tissue samples and cell lines compared with adjacent non‑cancerous tissues and the L02 normal liver epithelial cell line. PCAT‑1 suppression using PCAT‑1 small hairpin RNA in HepG2 and Bel‑7402 cells inhibited cell proliferation and migration, and induced apoptosis. Overexpression of PCAT‑1 induced synthetic plasmid vectors was demonstrated to increase cell proliferation and migration, and inhibit apoptosis. Results from the present study suggest that PCAT‑1 exerts an oncogenic effect in HCC and silencing PCAT-1 may be a potential novel therapeutic strategy for HCC.

Side population in hepatocellular carcinoma HCCLM3 cells is enriched with stem-like cancer cells

Substantial evidence implicates that low-abundance cancer stem cells (CSCs) are responsible for tumor metastasis and recurrence in hepatocellular carcinoma (HCC). Side population (SP) cells possess typical CSCs-like features, and are frequently considered as a special subpopulation in which CSCs are enriched and in studies may be considered as a substitute for CSCs. The aim of the present study was to examine the abundance of SP cells in human HCC cell lines with different metastatic potentials and compare their CSC-like, tumorigenic and invasive properties with those of the main population (MP) cells. An experimental system is described for identifying SP cells and analyzing their CSC-like properties. The relative abundance of SP cells correlated directly with the metastatic potential of the HCC cell line: HCCLM3, 16.3±2.2%; MHCC97-H, 8.4±0.7%; MHCC97-L, 4.7±0.5%; and Huh7, 1.0±0.3% (P<0.05). SP cells isolated from HCCLM3 cultures showed significantly higher proliferation rates and clonogenicity than the corresponding MP cells, in addition to higher migration and invasive abilities in vitro and greater tumorigenicity in mice. Expression levels of all CSC-associated genes tested, except EpCAM and Oct4, were significantly higher in SP cells. The findings revealed that the proportion of SP cells correlates with metastatic potential, and SP cells demonstrated the characteristics expected of CSCs, implicating them in HCC metastasis. Further studies on the identification and characterization of SP cells using clinical HCC specimens will contribute to the understanding of how SP cells are involved in these disease processes.

Hepatic resection provided long-term survival for patients with intermediate and advanced-stage resectable hepatocellular carcinoma

Background

Hepatic resection has the highest local controllability that results in long-term survival for hepatocellular carcinoma (HCC). This study aimed to investigate the role of hepatic resection in selected patients of intermediate and advanced stage.

Methods

Clinical, pathological, and outcome data of 542 consecutive patients were retrospectively analyzed from a single center. The Kaplan-Meier method was used to estimate survival. Postoperative prognostic factors were evaluated using univariate and multivariate analyses.

Results

The 1-, 3-, and 5-year overall survival rates were 89.0, 64.3, and 53.0 %, respectively. The 1-, 3-, and 5-year disease-free survival rates were 72.2, 44.5, and 34.2 %, respectively. Preoperative α-fetoprotein level >400 ng/mL, macroscopic vascular invasion, microscopic portal vein thrombosis, multiple tumor nodules, and the largest tumor size >5 cm were significantly correlated with overall survival. When these clinical risk factors were used in a postoperative staging system, assigning one point for each factor, the total score was precisely predictive of long-term survival. For patients with surgery plus adjuvant TACE (transarterial chemoembolization), the median overall survival was 56 months (range 1–110 months) and the 5-year OS rate was 48.5 %.

Conclusions

Hepatic resection is efficient and safe for HCC patients of intermediate and advanced stage. The adjuvant TACE should be recommended for HCC patients with poor risk factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12957-016-0811-y) contains supplementary material, which is available to authorized users.

Anti‑angiogenic therapy for normalization of tumor vasculature: A potential effect of Buyang Huanwu decoction on nude mice bearing human hepatocellular carcinoma xenografts with high metastatic potential

The present study aimed to investigate the effect of Buyang Huanwu decoction (BYHWD) on tumor growth, metastasis and angiogenesis in nude mice bearing human hepatocellular carcinoma (HCC) HCCLM3 xenografts. A total of 96 nude mice bearing HCCLM3 xenografts were randomly divided into four groups: BYHWD group (LB), Yi-qi decoction group (LY), Huo-xue decoction group (LH) and model group (LM). Each of these groups was divided into three subgroups (n=8), which were observed on days 21, 25, 38 following treatment, respectively. The tumor weights, volumes and pulmonary metastases were recorded. The expression of CD105 and the microvessel density (MVD) were assessed, and the expression levels of vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1α (HIF-1α), and regulator of G protein signaling 5 (RGS-5) were analyzed using immunohistochemical staining. Compared with the LM group, no significant decrease in tumor weight or volume were observed in the herbal medicine treatment groups, the number of the metastases in the lungs decreased, whereas the expression levels of RGS-5 and HIF-1α decreased in the LB group on day 35. However, the expression levels of VEGF increased in the LB group on days 28 and 35 post-treatment. The results of the present study suggested that BYHWD may inhibit angiogenesis and metastasis by affecting the expression levels of VEGF, RGS-5 and HIF-1α, and suggested that BYHWD may contribute to the tumor microenvironment and vasculature normalization in HCC.

The anti-metastatic effect of 8-MOP on hepatocellular carcinoma is potentiated by the down-regulation of bHLH transcription factor DEC1

Despite progress in diagnostics and treatment of hepatocellular carcinoma (HCC), its prognosis remains poor. 8-Methoxypsoralen (8-MOP), a formerly considered photosensitizing agent, has been reported to induce cell apoptosis in HepG2 cells in a modest way when used alone. In this study, it was demonstrated that 8-MOP inhibited HCC HepG2 cells and SMMC-7721 cells migratory and invasive potentiality, as well as modulated the expression of various EMT-associated genes such as enhancing E-cadherin and reducing N-cadherin, vimentin, α-SMA and MMP9 in a concentration-dependent way. Differentiated embryonic chondrocyte-expressed gene 1, DEC1 (BHLHE40/Stra13/Sharp2), is a basic helix-loop-helix (bHLH) transcription factor that regulates cell growth, differentiation, apoptosis and tumorigenesis. 8-MOP suppressed the expression of DEC1 in a concentration- and time-dependent manner. Overexpression of DEC1 endorsed the HepG2 cells a higher metastatic phenotype, while totally abolished 8-MOP-repressed metastatic capability. In the meanwhile, overexpression of DEC1 promoted EMT process by suppressing expression of epithelial protein and enhancing expression of mesenchymal proteins, while potently antagonized the regulation of EMT-associated genes by 8-MOP. In vivo experiments revealed that the treatment of 8-MOP (5 or 20mg/kg) resulted in a dose-dependent decreases in the lung metastasis of hepatoma H22-transplanted mice without any obvious toxicity to the organs, as well as increased expression of E-cadherin in lung tissues. Consistently, 8-MOP down-regulated the expression of DEC1 in the lungs of tumor-bearing mice, which further confirms that DEC1 was correlated with 8-MOP-induced anti-metastatic effect. The present findings establish a function for DEC1 in HCC metastatic progression and suggest its candidacy as a novel target for the anti-metastasis effect of 8-MOP.

miR-192, a prognostic indicator, targets the SLC39A6/SNAIL pathway to reduce tumor metastasis in human hepatocellular carcinoma

Metastasis is one of the causes of cancer death. Functions and mechanisms of microRNAs (miRNAs) involved in hepatocellular carcinoma (HCC) metastasis are largely unknown. Here, a miRNA microarray analysis was performed in MHCC-97L, MHCC-97H and HCC-LM3 cells with gradually increasing metastatic potential to disclose crucial miRNAs involved in HCC metastasis. miR-192 expression decreased and negatively correlated with vascular invasion in HCC specimens. Gain and loss of function studies revealed that miR-192 significantly suppressed metastasis of HCC cells in vitro and in vivo. Solute carrier family 39 member 6 (SLC39A6) was identified as a direct and functional target of miR-192. In addition, SLC39A6 negatively correlated with miR-192 in HCC samples and promoted HCC cell migration and invasion. Moreover, miR-192 decreased SLC39A6 expression, subsequently downregulating SNAIL and upregulating E-cadherin expression. Suppression of migration and invasion caused by miR-192 overexpression was alleviated by exogenous Snail expression. Intriguingly, lower miR-192 expression and higher SLC39A6 expression significantly contributed to poorer outcomes in HCC patients. Multivariate analysis indicated that miR-192 was an independent and significant predictor of HCC patient overall survival. In conclusion, we newly determined that miR-192 targeted the SLC39A6/SNAIL pathway to reduce tumor metastasis in HCC cells. This axis provided insights into the mechanism underlying miRNA regulation of HCC metastasis and a novel therapeutic target for HCC treatment.

Leukemia inhibitory factor receptor is a novel immunomarker in distinction of well-differentiated HCC from dysplastic nodules

Differential diagnosis of well-differentiated hepatocellular carcinoma (WD-HCC) and high-grade dysplastic nodules (HGDNs) represents a challenge for pathologists. Several immunohistochemistry markers have been identified to distinguish hepatocellular carcinoma (HCC) from HGDNs. However, sensitivity or specificity of the individual marker is still limited. In this study, we analyzed dynamic alteration of leukemia inhibitory factor receptor (LIFR) and CD34 during hepatocarcinogenesis from dysplastic nodules to small HCC. The diagnostic performance of LIFR and CD34 combination in WD-HCC and HGDNs was investigated by logistic regression models and validated in an independent validation cohort. LIFR was decreased and CD34 was increased along with stepwise progression of hepatocarcinogenesis from low-grade dysplastic nodules (LGDNs) to small HCC. The sensitivity and specificity of the LIFR and CD34 combination for WD-HCC detection were 93.5% and 90.5%, respectively. In addition, colony formation assay was used to explore the role of LIFR in tumorigenesis. Silencing of LIFR could significantly promote colony formation of HCC cells, whereas ectopic overexpression of LIFR resulted in impaired ability of colony formation of HCC cells. These findings indicate that LIFR and CD34 combination may be used as an available differential diagnostic model for WD-HCC from HGDNs in clinical practice.

Herbal Compound Songyou Yin and Moderate Swimming Suppress Growth and Metastasis of Liver Cancer by Enhancing Immune Function

Objective. Both the Chinese herbal compound Songyou Yin (SYY) and swimming exercise have been shown to have protective effects against liver cancer in animal models. In this study, we investigated whether SYY and moderate swimming (MS) have enhanced effect on suppressing progression of liver cancer by immunomodulation. Methods. C57BL/6 mice were transplanted with Hepa1-6 murine liver cancer cell lines and received treatment with SYY alone or SYY combined with MS. The green fluorescent protein (GFP)-positive metastatic foci in lungs were imaged with a stereoscopic fluorescence microscope. Flow cytometry was used to test the proportion of CD4 +, CD8 + T cells in peripheral blood and the proportions of CD4 + CD25 + Foxp3 + Treg cells in peripheral blood, spleen, and tumor tissues. Cytokine transforming growth factor (TGF)-β1 level in serum was detected by ELISA. Results. SYY plus MS significantly suppressed the growth and lung metastasis of liver cancer and prolonged survival in tumor-burdened mice. SYY plus MS markedly raised the CD4 to CD8 ratio in peripheral blood and lowered the serum TGF-β1 level and the proportions of Treg cells in peripheral blood, spleen, and tumor tissue. The effects of the combined intervention were significantly superior to SYY or MS alone. Conclusion. The combined application of SYY and MS exerted an enhanced effect on suppressing growth and metastasis of liver cancer by strengthening immunity.

Moderate swimming suppressed the growth and metastasis of the transplanted liver cancer in mice model: with reference to nervous system

Physical activity has been shown to suppress tumor initiation and progression. The neurotransmitter dopamine (DA) is closely related to movement and exhibits antitumor properties. However, whether the suppressive effects of physical activity on tumors was mediated by the nervous system via increased DA level remains unknowns. Here we show that regular moderate swimming (8 min/day, 9 weeks) raised DA levels in the prefrontal cortex, serum and tumor tissue, suppressed growth, reduced lung metastasis of transplanted liver cancer, and prolonged survival in a C57BL/6 mouse model, while overload swimming (16 and 32 min/day, 9 weeks) had the opposite effect. In nude mice that were orthotopically implanted with human liver cancer cell lines, DA treatment significantly suppressed growth and lung metastasis by acting on the D2 receptor (DR2). Furthermore, DR2 blockade attenuated the suppressive effect of moderate swimming on liver cancer. Both moderate swimming and DA treatment suppressed the transforming growth factor-beta (TGF-β1)-induced epithelial-mesenchymal transition of transplanted liver cancer cells. At the molecular level, DR2 signaling inhibited extracellular signal-regulated kinase phosphorylation and expression of TGF-β1 in vitro. Together, these findings demonstrated a novel mechanism by which the moderate exercise suppressed liver cancer through boosting DR2 activity, while overload exercise had the opposite effect, highlighting the possible importance of the dopaminergic system in tumor growth and metastasis of liver cancer.

JAK/STAT3 signaling regulates human telomerase reverse transcriptase via Leptin in hepatoma cells

AIM: To explore the influence of Leptin mediated JAK/STAT3 signaling on human telomerase reverse transcriptase (hTERT) in human liver cancer cells (HepG2) and elucidate the molecular mechanisms by which Leptin induces hTERT expression in hepatocellular carcinoma cells.

METHODS: The expression of ob-R in HepG2 cells was determined by Western blot. The expression of hTERT protein in cells after treatment with AG490 inhibitor was also detected by Western blot. Cell proliferation was detected by MTT method. The expression of hTERT mRNA was tested by RT-PCR, and the expression of hTERT protein was tested by Western blot.

RESULTS: HepG2 cells expressed ob-R. Western blot analysis showed that the hTERT protein expression in AG490 treatment group and AG490 plus Leptin treatment group was lower than that of Leptin treatment group. HepG2 cell proliferation was reduced after STAT3-siRNA transfection. The expression of hTERT protein and hTERT mRNA was reduced in STAT3-siRNA transfected HepG2 cells after treatment with STAT3 inhibitor.

CONCLUSION: HepG2 cells express ob-R. Leptin induced JAK-STAT3 signaling downregulates the hTERT mRNA and protein expression in hepatocellular carcinoma cells.

Down-regulation of SDF1-α expression in tumor microenvironment is associated with aspirin-mediated suppression of the pro-metastasis effect of sorafenib in hepatocellular carcinoma

Sorafenib is considered to be the first-line therapy for advanced hepatocellular carcinoma (HCC). It significantly delays tumor progression time; however, it increases the invasive and metastatic potential of HCC. Recent studies have shown that aspirin is effective in preventing and treating tumors, and the combination treatment of aspirin and sorafenib significantly suppresses sorafenib-induced intrahepatic metastasis. However, the mechanism through which aspirin suppresses the sorafenib-induced intrahepatic metastasis is still unclear. In this study, we find that sorafenib markedly increases stromal-derived factor 1-alpha (SDF1-α) expression in paratumor and intratumor tissues, and aspirin attenuates sorafenib-induced increase of SDF1-α expression in paratumor and intratumor tissues. Further studies show that SDF1-α improves cell invasion potential of HCC cells, and that AMD3100, a specific inhibitor of SDF1-α receptor CXCR4, suppresses the elevated intrahepatic metastatic potential of HCC induced by sorafenib in vivo. Collectively, this study reveals that the sorafenib-induced increase of SDF1-α expression in paratumor and intratumor microenvironments is suppressed by aspirin, which is associated with aspirin-mediated suppression of the pro-metastasis effect of sorafenib in HCC.

ANXA5 level is linked to in vitro and in vivo tumor malignancy and lymphatic metastasis of murine hepatocarcinoma cell

AIM

To investigate ANXA5 overexpression on in vitro and in vivo malignancies of murine Hca-P cells.

MATERIALS & METHODS

Hca-P with low lymph node metastasis (LNM) potential was used as cell model. TEM, CCK-8 and Boyden transwell assays were performed for in vitro Hca-P behaviors. Hca-P-transplanted mouse model was established for in vivo experiment.

RESULTS

ANXA5-overexpressing monoclonal Anxa5-Hca-P-1, Anxa5-Hca-P-2 and Anxa5-Hca-P-3 cells were obtained. ANXA5 upregulation alters the proliferation, morphology and rough endoplasmic reticulum of Hca-P cells, enhances in vitro migration and invasions of Hca-P, promotes in vivo malignant degree and LNM rate of Anxa5-Hca-P-3-transplanted mice.

CONCLUSION

As a potential indicator for malignancy and lymphatic metastasis, ANXA5 overexpression increases in vitro migration and invasion of Hca-P cell, promotes in vivo malignancy, LNM rate and level of Hca-P-transplanted mice.

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

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

Melittin suppresses cathepsin S-induced invasion and angiogenesis via blocking of the VEGF-A/VEGFR-2/MEK1/ERK1/2 pathway in human hepatocellular carcinoma

Melittin, a significant constituent of Apis mellifera (honeybee) venom, is a water-soluble toxic peptide that has traditionally been used as an antitumor agent. However, the underlying mechanisms by which it inhibits tumor cell growth and angiogenesis remain to be elucidated. In the present study, screening for increased cathepsin S (Cat S) expression levels was performed in MHCC97-H cells and various other hepatocellular carcinoma cell lines by reverse transcription-polymerase chain reaction and western blot analysis. A pcDNA3.1-small hairpin RNA (shRNA)-Cat S vector was stably transfected into MHCC97-H cells (shRNA/MHCC97-H) in order to knockdown the expression of Cat S. The effects resulting from the inhibition of Cat S-induced proliferation, invasion and angiogenesis by melittin were examined using cell proliferation, cell viability, flat plate colony formation, migration, wound healing, Transwell migration and ELISA assays. In order to substantiate the evidence for melittin-mediated inhibition of Cat S-induced angiogenesis, Cat S RNA was transfected into primary human umbilical vein endothelial cells (Cat S-HUVECs) to induce overexpression of the Cat S gene. The effects of melittin on HUVECs were examined using Transwell migration and tube formation assays. The findings demonstrated that melittin was able to significantly suppress MHCC97-H cell (Mock/MHCC97-H) proliferation, invasion and angiogenesis, as well as capillary tube formation of Cat S-HUVECs, in a dose-dependent manner. However, proliferation, invasion and angiogenesis in shRNA/MHCC97-H and in native HUVECs (Mock-HUVECs) were unaffected. In addition, melittin specifically decreased the expression of phosphorylated (activated) Cat S, and components of the vascular endothelial growth factor (VEGF)-A/VEGF receptor 2 (VEGFR-2)/mitogen-activated protein kinase kinase 1 (MEK1)/extracellular signal-regulated kinase (ERK)1/2 signaling pathway in Mock/MHCC97-H cells. In conclusion, the inhibition of tumor cell growth and anti-angiogenic activity exerted by melittin may be associated with anti-Cat S actions, via the inhibition of VEGF-A/VEGFR-2/MEK1/ERK1/2 signaling.

Peritumoural neutrophils negatively regulate adaptive immunity via the PD-L1/PD-1 signalling pathway in hepatocellular carcinoma

BACKGROUND

PD-L1 expression on neutrophils contributes to the impaired immune response in infectious disease, but the detailed role of PD-L1 expression on neutrophils in HCC remains unclear.

METHODS

We investigated the phenotype and morphology of neutrophils infiltrated in tumour tissues from both patients with HCC and hepatoma-bearing mice.

RESULTS

We found that neutrophils dominantly infiltrated in the peritumoural region. The neutrophil-to-T cell ratio (NLR) was higher in peritumoural tissue than that in the intratumoural tissue and was negatively correlated with the overall survival of patients with HCC. Infiltrating neutrophils displayed a phenotype of higher frequency of programmed cell death ligand 1 (PD-L1) positive neutrophils. The ratio of PD-L1(+) neutrophils-to-PD-1(+) T cells was higher in peritumoural tissue and better predicted the disease-free survival of patients with HCC. We further confirmed a higher frequency of PD-L1(+) neutrophils and PD-1(+) T cells in hepatoma-bearing mice. Functionally, the PD-L1(+) neutrophils from patients with HCC effectively suppressed the proliferation and activation of T cells, which could be partially reversed by the blockade of PD-L1.

CONCLUSIONS

Our results indicate that the tumour microenvironment induces impaired antitumour immunity via the modulation of PD-L1 expression on tumour infiltrating neutrophils.

Animal and cellular models of hepatocellular carcinoma bone metastasis: establishment and characterisation

BACKGROUND

An increasingly high occurrence of bone metastases in hepatocellular carcinoma (HCC) patients highlights the importance of fundamental research on HCC bone metastasis, which has been limited in its success due to the lack of a model system.

PURPOSE

Establishment of animal and cellular models of HCC bone metastasis and discovery of HCC bone metastasis-related genes.

METHODS

Luciferase-transfected HCC cell lines HCCLM3, MHCC97H, and SMMC-7721 were used to inoculate nude mice intracardially. Formation of bone metastases was examined by bioluminescence imaging, SPECT, and pathology study. Metastatic cells in bone were isolated and subcultured. Differences between bone metastatic cells and their parental cells were studied by in vitro/in vivo assays.

RESULTS

Mouse model of HCC bone metastasis was successfully established. Injected tumour cells formed metastases in the skull, the spine, the hind limbs, and the sternum, causing osteolytic lesions via act of MMP-1 and recruitment of osteoclasts. Four bone metastatic cell lines were extracted from HCCLM3-inoculated mice and were demonstrated to exhibit a much stronger ability to form bone metastases as well as other phenotypes, including enhanced in vitro migration/invasion and colony formation. Moreover, the expression of PTHrP, MMP-1, and CTGF was significantly elevated in bone metastatic cells compared to parental HCC cells.

CONCLUSION

The nude mouse model and bone metastatic cell lines together provide an effective simulation of HCC bone metastasis. This model system will become powerful tool with which to explore the mechanisms and therapies of HCC bone metastasis. Additionally, PTHrP, MMP-1, and CTGF are candidate genes related to HCC bone metastasis.

The nanomechanical signature of liver cancer tissues and its molecular origin

Patients with cirrhosis are at higher risk of developing hepatocellular carcinoma (HCC), the second most frequent cause of cancer-related deaths. Although HCC diagnosis based on conventional morphological characteristics serves as the "gold standard" in the clinic, there is a high demand for more convenient and effective diagnostic methods that employ new biophysical perspectives. Here, we show that the nanomechanical signature of liver tissue is directly correlated with the development of HCC. Using indentation-type atomic force microscopy (IT-AFM), we demonstrate that the lowest elasticity peak (LEP) in the Young's modulus distribution of surgically removed liver cancer tissues can serve as a mechanical fingerprint to evaluate the malignancy of liver cancer. Cirrhotic tissues shared the same LEP as normal tissues. However, a noticeable downward shift in the LEP was detected when the cirrhotic tissues progressed to a malignant state, making the tumor tissues more prone to microvascular invasion. Cell-level mechanistic studies revealed that the expression level of a Rho-family effector (mDia1) was consistent with the mechanical trend exhibited by the tissue. Our findings indicate that the mechanical profiles of liver cancer tissues directly varied with tumor progression, providing an additional platform for the future diagnosis of HCC.

The iron chelator Dp44mT inhibits hepatocellular carcinoma metastasis via N-Myc downstream-regulated gene 2 (NDRG2)/gp130/STAT3 pathway

Here we showed that hepatocellular carcinoma (HCC) cell lines with high metastatic potential had low levels of NDRG2. The iron chelator Dp44mT up-regulated NDRG2, suppressed epithelial-mesenchymal transition (EMT) and inhibited tumor metastasis in HCC having high metastatic potential. Also Dp44mT attenuated the TGF-β1-induced EMT in HCC having low metastatic potential. In agreement, silencing endogenous NDRG2 with shNDRG2 in HCC cells attenuated the effect of Dp44mT. We showed that the NDRG2/gp130/STAT3 pathway can mediate Dp44mT effects. In agreement, we found that a combination of NDRG2 expression and p-STAT3 levels is a strong predictor of prognosis in HCC patients. We suggest that up-regulation of NDRG2 by Dp44mT is a promising therapeutic approach in HCC.

Chemoembolization and stenting combined with iodine-125 seed strands for the treatment of hepatocellular carcinoma with inferior vena cava obstruction

The aim of the present study was to investigate the efficacy and safety of stenting combined with radioactive iodine-125 seed strands following chemoembolization for the treatment of patients with hepatocellular carcinoma and inferior vena cava (IVC) obstruction. A retrospective analysis was conducted of 52 hepatocellular carcinoma patients with IVC obstruction. All patients received chemoembolization of tumor-supplying arteries and IVC stents, and 18 patients additionally received iodine-125 seed strands, which were fixed to the stents. Improvement of IVC obstruction and the tumor response rates were compared between the two groups with a median follow-up time of 2.5 months. In both groups the stents were successfully deployed. At the 2-month post-procedural follow-up, the mean diameter of the IVC obstruction site, the mean pressure difference between the distal IVC obstructive segment and the right atrium as well as the obstruction scoring did not differ significantly between the two groups. By contrast, the tumor response rate of the iodine-125 seed strand group was 94.4%, whereas for the group without iodine-125 seed strands it was 35.3% (P<0.001). The combination of stent and iodine-125 seed strands was effective and safe for the treatment of hepatocellular carcinoma with IVC obstruction.

Assessment of endogenous reference gene suitability for serum exosomal microRNA expression analysis in liver carcinoma resection studies

Serum exosomal microRNAs (miRNAs) have received considerable attention as potential biomarkers for tumor diagnosis. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) is commonly used to detect miRNA expression levels in various types of cancer. One prerequisite for valid RT‑qPCR data is the correct normalization of miRNAs to stably expressed endogenous reference genes (RGs). The study of liver carcinoma resection requires the use of reliable RGs in order to assess the expression levels of serum exosomal target miRNAs. However, the assessment of RG suitability for optimum serum exosomal miRNA expression analysis has yet to be investigated. The present study investigated the expression stability of 10 candidate RGs. The candidate genes included eight miRNAs (miR‑16, miR‑103, miR‑191, let‑7a, miR‑26a, miR‑221, miR‑181a, and miR‑451) and two small RNAs (5S and U6). The stability values of the candidate genes were calculated using the following algorithms: geNorm, NormFinder, BestKeeper, and the comparative ΔCt method. The overall ranking obtained from these analyses revealed that miR‑221, let‑7a, and miR‑26a were appropriate internal RGs for analysis of serum miRNAs in patients with hepatocellular carcinoma. In addition, normalization with miR‑221 and let‑7a combined, as recommended by geNorm, or with miR‑26a, as recommended by NormFinder, increased the accuracy of interpretation of the target miRNA expression levels in hepatopathy studies.

Imbalance in systemic inflammation and immune response following transarterial chemoembolization potentially increases metastatic risk in huge hepatocellular carcinoma

Inflammation plays a critical role in tumor metastasis. However, few inflammation-related biomarkers are currently available to predict the risk of metastasis for advanced hepatocellular carcinoma (HCC). Using huge tumors (diameter >10 cm) as a model, we evaluated the potential risk of pre- and post-treatment inflammatory responses in the development of metastasis of HCC patients undergoing transarterial chemoembolization (TACE). A logistic regression model was used to analyze the risk factors. One hundred and sixty-five patients with huge HCC were enrolled in the study. Metastases were identified in 25.5% (42/165) patients by imaging evaluation post-TACE. Neutrophils increased, whereas lymphocytes decreased significantly post-TACE. Univariate analysis showed that high post-treatment neutrophil-to-lymphocyte ratio (NLR; p = 0.003), low post-treatment lymphocyte count (p = 0.047), and high baseline NLR (p = 0.100) were potential risk factors for metastasis. Further, multivariate analysis showed that high post-treatment NLR, but not pre-treatment NLR, was an independent risk factor for metastasis; this was confirmed by receiver operating characteristic curve analysis. Post-treatment NLR, however, had no correlation to tumor response and overall survival of patients. In conclusion, post-treatment NLR but not pre-treatment NLR independently increases the risk of metastasis in huge HCC. Our findings suggest the potential contribution of treatment-related inflammation to metastasis in advanced HCC.

Hepatocellular carcinoma-derived exosomes promote motility of immortalized hepatocyte through transfer of oncogenic proteins and RNAs

Exosomes are increasingly recognized as important mediators of cell-cell communication in cancer progression through the horizontal transfer of RNAs and proteins to neighboring or distant cells. Hepatocellular carcinoma (HCC) is a highly malignant cancer, whose metastasis is largely influenced by the tumor microenvironment. The possible role of exosomes in the interactions between HCC tumor cell and its surrounding hepatic milieu are however largely unknown. In this study, we comprehensively characterized the exosomal RNA and proteome contents derived from three HCC cell lines (HKCI-C3, HKCI-8 and MHCC97L) and an immortalized hepatocyte line (MIHA) using Ion Torrent sequencing and mass spectrometry, respectively. RNA deep sequencing and proteomic analysis revealed exosomes derived from metastatic HCC cell lines carried a large number of protumorigenic RNAs and proteins, such as MET protooncogene, S100 family members and the caveolins. Of interest, we found that exosomes from motile HCC cell lines could significantly enhance the migratory and invasive abilities of non-motile MIHA cell. We further demonstrated that uptake of these shuttled molecules could trigger PI3K/AKT and MAPK signaling pathways in MIHA with increased secretion of active MMP-2 and MMP-9. Our study showed for the first time that HCC-derived exosomes could mobilize normal hepatocyte, which may have implication in facilitating the protrusive activity of HCC cells through liver parenchyma during the process of metastasis.

WP1130 increases doxorubicin sensitivity in hepatocellular carcinoma cells through usp9x-dependent p53 degradation

Resistance to chemotherapeutic drugs is a major obstacle in hepatocellular carcinoma (HCC) therapy. However, the underlying mechanisms are not well understood. Recent evidence suggests that deubiquitinases (DUB) are key regulators in the mechanisms of cell proliferation, apoptosis and chemoresistance. The present study aimed to investigate whether WP1130, which inhibits activity of deubiquitinases, exerts synergistic cytotoxicity with doxorubicin in HCC and the underlying mechanisms. In the study, we found that Huh7, HepG2, and SNU387 HCC cells with p53 expression displayed enhanced response to the combination therapy compared with p53-deficient HCC cells (Hep3B) in the manner of inhibiting cell proliferation. Downregulation of p53 abolished the synergistic cytotoxicity of doxorubicin and WP1130 on HCC cells. Mechanistically, we found that combined treatment with WP1130 suppressed doxorubicin-mediated upregulation of p53 via promoting its ubiquitin-proteasome dependent degradation, whereas knockdown of DUB usp9x abolished this effect. Taken together, these results demonstrate that combined treatment with WP1130 sensitized HCC cells to doxorubicin via usp9x-depedent p53 degradation.

Association between donor and recipient smoothened gene polymorphisms and the risk of hepatocellular carcinoma recurrence following orthotopic liver transplantation in a Han Chinese population

Hepatocellular carcinoma (HCC) recurrence after orthotopic liver transplantation (OLT) is potential cause for the poor outcome. Smoothened (SMO) gene has been considered associating with HCC and HCC recurrence, but its association with HCC recurrence after OLT is not clear yet. In this study, we aim at evaluating the association between donor and recipient SMO gene polymorphisms and HCC recurrence after OLT. A total of 76 patients with HCC who had undergone OLT from July 2007 to August 2012 were included. A single nucleotide polymorphism (SNP), SMO rs3824, located at the 3'UTR region, was genotyped and analyzed in both donor and recipient. We demonstrated that recipient rs3824 polymorphism was significantly associated with HCC recurrence following OLT. In multivariate logistic regression analysis, TNM stage (p = 0.001), recipient SMO rs3824 genotype (CG vs. CC/GG p = 0.001), and histologic grade (p = 0.019) were identified as independent risk factors of HCC recurrence. Recurrence-free survival (RFS) and overall survival (OS) were significantly higher in the recipient CC/GG group than in the CG group (p = 0.003 and p = 0.011, respectively). Cox proportional hazards modeling revealed that TNM stage, recipient SMO rs3824 genotype, pre-OLT serum AFP level, and histologic grade were independent factors (p < 0.05) for patients' clinical outcomes. In conclusion, recipient SMO rs3824 polymorphism is associated with an increased risk of HCC recurrence following OLT and has a potential clinical value for the prognosis of HCC patients treated with OLT.

A Huaier polysaccharide reduced metastasis of human hepatocellular carcinoma SMMC-7721 cells via modulating AUF-1 signaling pathway

TP-1 is a polysaccharide from one famous fungus Huaier. Treatment with TP-1 significantly inhibited the cell growth, adhesion, migration, and motility of SMMC-7721 cells in a dose-dependent manner. Real-time quantitative RT-PCR revealed a dose-dependent decrease in RNA-binding factor 1 (AUF-1) and astrocyte elevated gene-1 (AEG-1) messenger RNA (mRNA) levels in TP-1-treated SMMC-7721 cells, which is consistent with their protein expression detected by Western blotting. On the contrary, microRNA-122 (miR-122) expression increased in SMMC-7721 cells following TP-1 treatment. Moreover, TP-1 treatment at three doses apparently increased epithelial marker E-cadherin protein expression but decreased the mesenchymal marker N-cadherin protein level. In addition, the hematoxylin-eosin (H & E) staining showed that the TP-1 significantly inhibited the lung metastasis of liver cancer in mice orthotopic implanted with SMMC-7721 tumor tissue. Taken together, these findings proved the inhibitory effect of TP-1 on the growth and metastasis of SMMC-7721 cells, and TP-1 might be offered for future application as a powerful chemopreventive agent against hepatocellular carcinoma (HCC) metastasis.

Expression of NEDD9 in hepatocellular carcinoma and its clinical significance

Neural precursor cell expressed, developmentally downregulated 9 (NEDD9) plays an integral role in natural and pathological cell biology. Overexpression of NEDD9 protein has been correlated with poor prognosis in various types of cancer. However, few available data address the precise function of the NEDD9 gene in hepatocellular carcinoma (HCC). In the present study, we investigated NEDD9 expression in 40 primary human HCC tissues compared with matched adjacent non-tumor hepatic tissues using RT-qPCR and western blot analysis. Immunohistochemistry was performed to analyze the correlations between NEDD9 expression and clinicopathological factors. Statistical analyses were applied to derive prognostic values of NEDD9 in HCC. The results showed that the NEDD9 mRNA and protein expression levels in HCC tissues were significantly higher than those in matched adjacent non-tumor hepatic tissues. High NEDD9 expression was correlated with larger tumor size, advanced tumor grade, metastasis, intrahepatic venous invasion and high UICC TNM stages in HCC patients. Patients with high NEDD9 expression levels exhibited poorer recurrence-free and overall survival than those with a low NEDD9 expression. Additionally, NEDD9 expression status was an independent prognostic factor for survival. This correlation remained significant in patients with early-stage HCC or with normal serum AFP levels. The results of this study suggest that NEDD9 may be a valuable prognostic biomarker for HCC, including early-stage and AFP-normal patients.

Adjuvant sorafenib therapy in patients with resected hepatocellular carcinoma: evaluation of predictive factors

Currently there is no predictor for survival after adjuvant sorafenib in patients with hepatocellular carcinoma (HCC) who have undergone curative resection. Thirty-eight patients who underwent curative resection of HCC received adjuvant sorafenib therapy between August 2009 and March 2012. Clinicopathological parameters including patient factors, tumor factors, liver background, and inflammatory factors (before surgery and dynamic changes after sorafenib therapy) were evaluated to identify predictors for overall survival (OS) and recurrence-free survival (RFS). The recurrence rate, mortality rate, and clinicopathological data were also compared. Increased NLR after sorafenib (HR = 3.199, 95 % CI 1.365-7.545, P = 0.008), increased GGT after sorafenib (HR = 3.204, 95 % CI 1.333-7.700, P = 0.009), and the presence of portal vein thrombosis (HR = 2.381, 95 % CI 1.064-5.328, P = 0.035) were risk factors related to RFS. By contrast, increased NLR after sorafenib was the only independent risk factor related to OS (HR = 4.647, 95 % CI 1.266-17.053, P = 0.021). Patients with increased NLR or increased GGT after sorafenib had a higher incidence of recurrence and death. Patients who had increased NLR tended to have higher preoperative levels of NLR and GGT. There were no differences in clinicopathological factors in patients with increased GGT and decreased GGT. In conclusion, increased NLR predicted a worse OS and RFS in patients with HCC who underwent curative resection with adjuvant sorafenib therapy. Increased GGT predicted a worse OS. NLR and GGT can be monitored dynamically before and after sorafenib therapy.

Interactions between osteopontin and vascular endothelial growth factor: Implications for cancer

For this comprehensive review, 257 publications with the keywords "osteopontin" or "OPN" and "vascular endothelial growth factor" or "VEGF" in PubMed were screened (time frame from year 1996 to year 2014). 37 articles were excluded because they were not focused on the interactions between these molecules, and papers relevant for transformation-related phenomena were selected. Osteopontin (OPN) and vascular endothelial growth factor (VEGF) are characterized by a convergence in function for regulating cell motility and angiogenesis, the response to hypoxia, and apoptosis. Often, they are co-expressed or one molecule induces the other, however, in some settings OPN-associated pathways and VEGF-associated pathways are distinct. Their relationships affect the pathogenesis in cancer, where they contribute to progression and angiogenesis and serve as markers for poor prognosis. The inhibition of OPN may reduce VEGF levels and suppress tumor progression. In vascular pathologies, these two cytokines mediate remodeling, but may also perpetuate inflammation and narrowing of the arteries. OPN and VEGF are elevated and contribute to vascularization in inflammatory diseases.

Glycosylation and liver cancer

Liver cancer is the fifth most common cancer, but the second leading cause of cancer death, in the world, with more than 700,000 fatalities annually. The major etiology of liver cancer is infection with an hepatotropic virus such as hepatitis B virus or hepatitis C virus infection. While chronic viral infection remains the main cause of liver disease and risk of hepatocellular carcinoma (HCC), rates of nonviral-associated HCC are occurring at an alarmingly increasing rate. Like many cancers, survival rates are closely associated with time of detection. If HCC is caught early, survival rates can be as high as 50%. Regrettably, most cases of HCC are caught late where survival rates can be as low as 2-7%. Thus, there has been great interest in discovering serum biomarkers that could be used to identify those with HCC. To this end, many groups have examined the N-linked glycans to identify changes that occur with HCC. As the liver secretes the vast majority of proteins into the serum, this has often been a starting point for study. In serum, alterations in core fucosylation, outer-arm fucosylation, increased sialylation, and glycan branching have been observed in patients with HCC. Similar findings have been found directly in HCC tissue suggesting that these glycan changes may play a role in tumor formation and development.

Quercetin Induces Antiproliferative Activity Against Human Hepatocellular Carcinoma (HepG2) Cells by Suppressing Specificity Protein 1 (Sp1)

Preclinical Research Quercetin, found in red onions and red apple skin can induce apoptosis insome malignant cells. However, the apoptotic effect of quercetin in hepatocellular carcinoma HepG2 cells via regulation of specificity protein 1 (Sp1) has not been studied. Here, we demonstrated that quercetin decreased cell growth and induce apoptosis in HepG2 cells via suppression of Sp1 using 3-(4,5-dimethyl-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, 4',6-diamidino-2-phenylindole (DAPI) staining, Annexin V, and Western blot analysis, an effect that was dose- and time-dependent manner. Treatment of HepG2 cells with quercetin reduced cell growth and induced apoptosis, followed by regulation of Sp1 and Sp1 regulatory protein. Taken together, the results suggest that quercetin can induce apoptotic cell death by regulating cell cycle and suppressing antiapoptotic proteins. Therefore, quercetin may be useful for cancer prevention. Drug Dev Res 76 : 9-16, 2015.

Preclinical trials for prevention of tumor progression of hepatocellular carcinoma by LZ-8 targeting c-Met dependent and independent pathways

Hepatocellular carcinoma (HCC) is among the most lethal cancers. Mounting studies highlighted the essential role of the HGF/c-MET axis in driving HCC tumor progression. Therefore, c-Met is a potential therapeutic target for HCC. However, several concerns remain unresolved in c-Met targeting. First, the status of active c-Met in HCC must be screened to determine patients suitable for therapy. Second, resistance and side effects have been observed frequently when using conventional c-Met inhibitors. Thus, a preclinical system for screening the status of c-Met signaling and identifying efficient and safe anti-HCC agents is urgently required. In this study, immunohistochemical staining of phosphorylated c-Met (Tyr1234) on tissue sections indicated that HCCs with positive c-Met signaling accounted for approximately 46% in 26 cases. Second, many patient-derived HCC cell lines were established and characterized according to motility and c-Met signaling status. Moreover, LZ8, a medicinal peptide purified from the herb Lingzhi, featuring immunomodulatory and anticancer properties, was capable of suppressing cell migration and slightly reducing the survival rate of both c-Met positive and negative HCCs, HCC372, and HCC329, respectively. LZ8 also suppressed the intrahepatic metastasis of HCC329 in SCID mice. On the molecular level, LZ8 suppressed the expression of c-Met and phosphorylation of c-Met, ERK and AKT in HCC372, and suppressed the phosphorylation of JNK, ERK, and AKT in HCC329. According to receptor array screening, the major receptor tyrosine kinase activated in HCC329 was found to be the epidermal growth factor receptor (EGFR). Moreover, tyrosine-phosphorylated EGFR (the active EGFR) was greatly suppressed in HCC329 by LZ8 treatment. In addition, LZ8 blocked HGF-induced cell migration and c-Met-dependent signaling in HepG2. In summary, we designed a preclinical trial using LZ8 to prevent the tumor progression of patient-derived HCCs with c-Met-positive or -negative signaling.

FoxM1 overexpression promotes epithelial-mesenchymal transition and metastasis of hepatocellular carcinoma

AIM: To investigate the expression of forkhead box protein M1 (FoxM1) in the process of epithelial mesenchymal transition in hepatocellular carcinoma (HCC) and its role in metastasis.

METHODS: FoxM1 and E-cadherin expression in HCC tissue microarray specimens was evaluated by immunohistochemical staining, and statistical methods were applied to analyze the correlation between FoxM1 and epithelial-mesenchymal transition (EMT). Kaplan-Meier analysis of the correlation between the FoxM1 expression level and recurrence or overall survival of HCC patients was performed. The expression of FoxM1, E-cadherin and snail homologue 1 (SNAI1) in HCC cell lines was evaluated by real-time reverse transcription-polymerase chain reaction and Western blot. Hepatocyte growth factor (HGF) was used to induce EMT and stimulate cell migration in HCC cells. The expression of FoxM1 and SNAI1 was regulated by transfection with plasmids pcDNA3.1 and siRNAs in vitro. The occurrence of EMT was evaluated by Transwell assay, morphologic analysis and detection of the expression of EMT markers (E-cadherin and vimentin). Luciferase and chromatin immunoprecipitation assays were used to evaluate whether SNAI1 is a direct transcriptional target of FoxM1.

RESULTS: FoxM1 expression was increased significantly in HCC compared with para-carcinoma (10.7 ± 0.9 vs 8.2 ± 0.7, P < 0.05) and normal hepatic (10.7 ± 0.9 vs 2.7 ± 0.4, P < 0.05) tissues. Overexpression of FoxM1 was correlated with HCC tumor size, tumor number, macrovascular invasion and higher TNM stage, but was negatively correlated with E-cadherin expression in microarray specimens and in cell lines. FoxM1 overexpression was correlated significantly with HCC metastasis and EMT. In vitro, we found that FoxM1 plays a key role in HGF-induced EMT, and overexpression of FoxM1 could suppress E-cadherin expression and induce EMT changes, which were associated with increased HCC cell invasiveness. Next, we confirmed that FOXM1 directly binds to and activates the SNAI1 promoter, and we identified SNAI1 as a direct transcriptional target of FOXM1. Moreover, inhibiting the expression of SNAI1 significantly inhibited FoxM1-mediated EMT.

CONCLUSION: FoxM1 overexpression promotes EMT and metastasis of HCC, and SNAI1 plays a critical role in FoxM1-mediated EMT.

B cell CLL/lymphoma 6 member B inhibits hepatocellular carcinoma metastases in vitro and in mice

B cell CLL/lymphoma 6 member B (BCL6B) is a novel tumor suppressor silenced in human cancer. In this study, we investigated the functional role and underlying mechanisms of BCL6B in hepatocellular carcinoma (HCC). BCL6B was expressed in normal HCC tissues, but its expression was suppressed in 6 out of 9 HCC cell lines. Loss of BCL6B expression was associated with promoter hypermethylation. Ectopic expression of BCL6B in HepG2 and Huh7 cell lines inhibited colony formation (P <0.05), cell viability (P <0.01), and tumorigenicity in nude mice (P <0.05). BCL6B expression also induced apoptosis (P <0.05), an effect associated with activation of the caspase cascade and cleavage of PARP. Stable expression of BCL6B in MHCC97L cells suppressed cell migration (P <0.05) and invasion (P <0.05), and significantly reduced the incidence and severity of lung metastasis in an orthotopic HCC mouse model. The anti-metastatic effect of BCL6B was mediated by up-regulation of cell adhesion gene E-cadherin, OB-cadherin, HIV-1 Tat interactive protein 2, and transient receptor potential cation channel, subfamily M, member 1; and down-regulation of angiogenesis gene VEGFA. BCL6B functions as a tumor suppressor that inhibits HCC metastases in vitro and in vivo.

SPHK1 inhibitor suppresses cell proliferation and invasion associated with the inhibition of NF-κB pathway in hepatocellular carcinoma

Sphingosine kinase 1 (SphK1) is an oncogenic enzyme promoting transformation, proliferation, and angiogenesis of a number of human tumors. However, its effect on hepatocellular carcinoma (HCC) behavior has not been fully clarified. The purpose of this study was to determine the correlation between HCC and SphK1, and to evaluate the effect of SphK1 inhibitor N,N-dimethylsphingosine (DMS) in HCC. The expression of SphK1 was measured in tissue samples from 76 HCC and paired adjacent noncancerous liver tissues (NT) by immunohistochemistry, quantitative real-time PCR, and Western blotting analysis. The effect of DMS was tested on HCC cells by evaluating cell viability in vitro. Transwell cell migration and invasion assay were carried out for functional analysis. Furthermore, Western blotting analysis was performed to examine the impact of DMS on the PI3K/Akt/NF-kB signaling. High expression of Sphk1 was observed in 84.21% (64/76) of the HCC versus 15.79% (12/76) of the adjacent non-tumorous liver tissues; the difference of Sphk1 expression between HCC and the adjacent non-tumorous liver tissues was statistically significant (P < 0.001). The results were confirmed by Western blot analyses and quantitative real-time PCR. DMS inhibited the proliferation of SK-Hep1 and MHCCLM3 cells which have a relatively high level of SphK1 in a time- and concentration-dependent manner, and the invasion and migration of SK-Hep1 cells were distinctly suppressed after undergoing treatment with DMS. Furthermore, DMS markedly suppressed the expression of phosphorylations of Akt and NF-κB in HCC cells. Our data suggest that the pathogenesis of human HCC maybe mediated by Sphk1, and the specific Sphk1 inhibitor DMS can play a therapeutic role in the treatment of HCC and thus, Sphk1 could represent selective targets for the molecularly targeted treatments of HCC.

Pathway crosstalk analysis of microarray gene expression profile in human hepatocellular carcinoma

Liver cancer is the third most common cause of cancer death in the world. Hepatocellular carcinoma (HCC) is the main pathological types in liver cancer, which amounts to 70-85 % of primary liver cancer in the world and 90 % in China. The aim of this study was to establish a PPI network and a pathway crosstalk network to isolate important dysfunctional pathways which play an important role in the pathogenesis of HCC. System biology approach was used in this research. A PPI network was firstly built and then a dysfunctional crosstalk network of HCC related pathways was constructed. Several important significant dysfunctional crosstalk pathways were identified. Basal transcription factors (hsa03022), Glycerophospholipid metabolism (hsa00564) and Metabolism of xenobiotics by cytochrome P450 (hsa00980) were significantly interact with Pathway in cancer (hsa05200). Besides, pathway Axon guidance (hsa04360) was also dysfunctional crosstalk with Pathway in cancer (hsa05200). The crosstalks among these pathways reveal some evidence that the pathways closely cooperated and play important tasks in HCC progression. Besides, the pathway hsa04360 dysfunctional crosstalk with the hsa05200 indicates there would be a same mechanism for HCC invasion and migration.

Preserving hepatic artery flow during portal triad blood inflow occlusion reduces the outgrowth of hepatocarcinoma in mice after ischemia-reperfusion

AIM

To investigate the effect of different hepatic vascular occlusion maneuvers on the growth of hepatocarcinoma after liver ischemia-reperfusion (I/R) injury.

METHODS

A mice hepatocarcinoma model was established by portal vein injection of H22 hepatoma cells. After 3 days, the mice underwent sham operation, occlusion of portal triad (OPT), portal vein (OPV), or intermittent clamping (INT) operation. The hepatic I/R injury, pathological changes, hepatic replacement area, proliferative cell nuclear antigen expression, and extracellular signal-regulated kinase (ERK) 1/2 activation were assessed 5 days after reperfusion.

RESULTS

Alanine aminotransferase and aspartate aminotransferase levels in the OPV group were significantly lower than those in the OPT and INT groups at 24 h after reperfusion. The hepatic injury of clamped liver lobes in the OPV group, represented by histopathological alterations and myeloperoxidase activity, was much slighter than that in the OPT and INT groups. The values of hepatic replacement area in the sham operation, OPT, OPV, and INT groups were 7.661 2.55%, 35.61 1 4.23%, 9.02 1 3.01%, and 19.95 1 4.10%, respectively. Proliferative cell nuclear antigen expression and ERK1/2 activation of tumor cells were the highest in the OPT group, and the lowest in the OPV and INT groups.

CONCLUSION

Preserving hepatic artery flow during portal triad blood inflow occlusion substantially inhibits the outgrowth of hepatocarcinoma via attenuating hepatic I/R injury in a murine liver tumor model. These results suggest a better prevention of hepatic tumor outgrowth after hepatectomy by using the selective portal vein clamping method in liver cancer patients.

Goosecoid promotes the metastasis of hepatocellular carcinoma by modulating the epithelial-mesenchymal transition

The homeobox gene, goosecoid (GSC), is a transcription factor that participates in cell migration during embryonic development. Because cell migration during development has characteristics similar to cell invasion during metastasis, we evaluated the potential role of GSC in the metastasis of hepatocellular carcinoma (HCC). GSC expression in HCC cell lines and tissues was evaluated, and its effects on the migration potential of HCC cells were determined by GSC knock-down and overexpression methods. In addition, the prognostic role of GSC expression in the metastasis of cancer cells in HCC patients was determined. Our data showed that GSC was highly expressed in several HCC cell lines, particularly in a highly metastatic HCC cell line. Overexpression of GSC promoted cell migration and invasion of HCC cells in vitro. Gain-of-function induced the epithelial-mesenchymal transition but not collective cell migration, whereas loss-of-function induced the reverse change. High-level expression of GSC correlated closely with poor survival and lung metastasis in HCC patients; lung metastases showed more upregulated GSC expression than the primary tumor. We conclude that GSC promotes metastasis of HCC potentially through initiating the epithelial-mesenchymal transition. GSC is also a prognostic factor for poor survival and metastasis of HCC, which suggests its potential as a therapeutic target for metastatic HCC.

Hypoxia-induced secretion of platelet-derived growth factor-BB by hepatocellular carcinoma cells increases activated hepatic stellate cell proliferation, migration and expression of vascular endothelial growth factor-A

Angiogenesis has an important function in the proliferation and metastasis of hepatocellular carcinoma (HCC) under a hypoxic tumor microenvironment. Activated hepatic stellate cells (HSCs) infiltrate the stroma of liver tumors and potently increase angiogenesis through tumor-stromal interactions, however, the exact mechanism by which this occurs is unknown. The present study aimed to investigate the paracrine effects of HCC-derived platelet-derived growth factor-BB (PDGF-BB) on HSCs under hypoxic conditions. It was demonstrated that PDGF-BB expression was markedly increased in HepG2 cells exposed to hypoxia. Conditioned medium (CM) from HepG2 cells stimulated LX-2 cell proliferation, migration and vascular endothelial growth factor-A (VEGF-A) expression. It was then determined that blocking PDGF-BB expression in HepG2-CM abolished these effects on LX-2 cells. The ectopic expression of PDGF-BB in HepG2 cells strongly affected LX-2 cell proliferation, migration and VEGF-A expression. In conclusion, the present study suggests that hypoxia-induced PDGF-BB secretion by HCC cells stimulates HSCs to accumulate and proliferate in the tumor stroma and the enhanced VEGF-A expression in HSCs may promote HCC angiogenesis.

Altered distribution and expression pattern of E-cadherin in hepatocellular carcinomas: correlations with prognosis and clinical features

OBJECTIVE

E-cadherin has been identified as a tumor suppressor in many types of carcinoma. However, some studies recently suggested that the role and expression of E-cadherin might be more complex and diverse. In the present study, we evaluated the prognostic value of E-cadherin expression with reference to levels in membranes and cytoplasm, and the membrane/cytoplasm ratio, in hepatocellular carcinomas (HCCs) after curative hepatectomy.

METHODS

The expression of E-cadherin was assessed by immunohistochemistry in HCC tissue microarrays from 125 patients, and its prognostic values and other clinicopathlogical data were retrospectively analyzed. Patients were followed for a median period of 43.7 months (range 1 to 126 months).

RESULTS

Univariate analysis demonstrated that a high membrane/cytoplasm (M/C) ratio of E-cadherin expression was associated with poor overall survival (OS) (P =0.001) and shorter time to recurrence (TTR) (P =0.038), as well as tumor size, intrahepatic metastasis, and TNM stage. In contrast, neither membrane nor cytoplasmic expression of E-cadherin was related with OS and TTR. Furthermore, multivariate analysis confirmed the M/C ratio to be an independent predictor of OS (P =0.031). ?2 tests additionally showed that the M/C ratio of E-cadherin expression was related with early stage recurrence (P =0.012), rather than later stage recurrence.

CONCLUSION

The M/C ratio of E-cadherin expression is a strong predictor of postoperative survival and is associated with early stage recurrence in patients with HCC.

MicroRNA-331-3p promotes proliferation and metastasis of hepatocellular carcinoma by targeting PH domain and leucine-rich repeat protein phosphatase

Hepatocellular carcinoma (HCC) is a highly invasive tumor with frequent intrahepatic or pulmonary metastasis, which is the main reason for high recurrence and poor survival of HCC after liver resection. However, the mechanisms for metastasis remain incompletely clear. Given that microRNAs (miRNAs) are implicated in HCC progression, we explored a potential role of miRNAs in metastasis by performing miRNA expression profiling in three subtypes of HCC with different metastatic potentials. We discovered miR-331-3p as one of most significantly overexpressed miRNAs and highly associated with metastasis of HCC. Increased expression of miR-331-3p was correlated with poor long-term survival of HCC. We provided both in vivo and in vitro evidence demonstrating that miR-331-3p promoted proliferation and metastasis of HCC cells. Using an integrated approach, we uncovered that PH domain and leucine-rich repeat protein phosphatase (PHLPP) was a novel target of miR-331-3p. Indeed, the miR-331-3p-mediated effects were antagonized by reexpression of PHLPP or mimicked by silencing of PHLPP. We further showed that miR-331-3p-mediated inhibition of PHLPP resulted in stimulation of protein kinase B (AKT) and subsequent epithelial mesenchymal transition (EMT). Finally, inhibition of miR-331-3p through a jetPEI-mediated delivery of anti-miR-331-3p vector resulted in marked inhibition of proliferation and metastasis of HCC in xenograft mice.

CONCLUSION

miR-331-3p promotes proliferation and EMT-mediated metastasis of HCC through suppression of PHLPP-mediated dephosphorylation of AKT. Our work implicates miR-331-3p as a potential prognostic biomarker and a novel therapeutic target.

miR-1285-3p acts as a potential tumor suppressor miRNA via downregulating JUN expression in hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is one of the most common and most lethal cancers. Currently, standard therapy for unresectable HCC is a local-regional therapy with transarterial chemoembolisation (TACE). In this study, we sought to assess whether plasma circulating microRNAs (miRNAs) can be used to predict the prognosis of HCC patients receiving the TACE treatment. Firstly, we systematically examined TACE therapeutic effectiveness-related circulating miRNAs through miRNA Profiling Chips. As a result, we identified 19 circulating miRNAs to be significantly differentially expressed between the TACE-response group and the TACE-nonresponse group. In the second stage, we performed quantitative analyses of these candidate miRNAs in additional HCC patients treated with TACE and validated two of the aforementioned 19 miRNAs (miR-1285-3p and miR-4741) as candidate biomarkers for predicting prognosis of TACE. Interestingly, we found that miR-1285-3p could directly repress JUN oncogene expression in HCC cells, indicating miR-1285-3p could act as a potential tumor suppressor. In conclusion, our data indicate that circulating miR-1285-3p and miR-4741 was predictive of response to TACE therapy in HCC.

Label-free quantitative detection of tumor-derived exosomes through surface plasmon resonance imaging

Exosomes are endosome-derived membrane vesicles carrying proteins and nucleic acids that are involved in cellular functions such as intercellular communication, protein and RNA secretion, and antigen presentation. Therefore, exosomes serve as potential biomarkers for many diseases including cancer. Because exosomes are difficult to enrich or purify from biofluids, quantification of exosomes is tedious and inaccurate. Here, we present a real-time, label-free, and quantitative method to detect and characterize tumor-derived exosomes without enrichment or purification. Utilizing surface plasmon resonance imaging (SPRi) in combination with antibody microarrays specific to the extracellular domains of exosome membrane proteins, exosomes in tumor cell culture medium can be quantitatively detected. We found a positive correlation between the metastatic potential of tumor cell lines and exosome secretion. This method provides an easy, efficient, and novel way to detect exosome secretion and thus an avenue toward the diagnosis and prognosis prediction of cancer.