Long non-coding RNA RP11-284P20.2 promotes cell proliferation and invasion in hepatocellular carcinoma by recruiting EIF3b to induce c-met protein synthesis.

A newly identified lncRNA designated as RP11-284P20.2 has been identified to be up-regulated in hepatocellular carcinoma (HCC), but its role in HCC remain poorly understood. Quantitative PCR and immunocytochemical analysis were performed using the HCC tissues to identify the potential interaction partners of RP11-284P20.2. Moreover, RP11-284P20.2 was knocked down in HCC cell lines, HepG2 and SMMC7721, to investigate the influence of this lncRNA on cell growth properties. Additionally, RNA fluorescence in situ hybridization and immunofluorescence, RNA immunoprecipitation, and RNA pull-down assays were performed to determine the interaction of RP11-284P20.2 with c-met mRNA and eukaryotic translation initiation factor 3b (EIF3b). Silencing RP11-284P20.2 inhibited cell viability, migration, invasion, and colony formation, and increased apoptosis. Overexpression of c-met abolished these effects of RP11-284P20.2 in HCC cells. Histopathological examination showed that HCC tissues with high RP11-284P20.2 expression had higher c-met protein level than that in HCC tissues with low RP11-284P20.2 expression. However, there was no positive correlation between the expression levels of RP11-284P20.2 and c-met mRNA. RP11-284P20.2 knockdown led to a decease in c-met protein expression level, but did not affect the c-met mRNA expression level. These data suggest that RP11-284P20.2 regulates c-met protein expression level, which is independent of c-Met mRNA expression level. It was also confirmed that RP11-284P20.2 has high affinity toward both c-met mRNA and EIF3b protein, and hence RP11-284P20.2 probably recruits EIF3b protein to c-met mRNA and further facilitates its translation. RP11-284P20.2 promotes cell proliferation and invasion in hepatocellular carcinoma by recruiting EIF3b to induce c-met protein synthesis.

Detection of a novel panel of somatic mutations in plasma cell-free DNA and its diagnostic value in hepatocellular carcinoma.

Background/aims: Circulating cell-free DNA (cfDNA) contains tumor-specific alterations and could potentially serve as "liquid biopsy". The study was to identify a novel panel of hepatocellular carcinoma (HCC)-specific mutations in plasma cfDNA and to assess its value in the diagnosis of HCC. Materials and methods: 33 HCC tissue, 37 blood, and 37 swab specimens were collected from HCC patients and control individuals. Genomic DNA was subjected to next-generation sequencing. The selected mutations in the plasma cfDNA in the HCC versus control groups were compared, and the diagnostic performance of cfDNA mutations was evaluated. Results: A majority of selected mutations in the HCC tissue DNA, ranging from 52% to 84%, was detected in the matched plasma cfDNA. For the selected mutations, receiver operating characteristic (ROC) analysis revealed an area under the ROC curve (AUC) of 0.92, sensitivity of 65%, and specificity of 100% for the diagnosis of HCC regardless of alpha-fetoprotein (AFP) status. Detection of the selected mutations in cfDNA in combination with AFP exhibited better diagnosis performance, with AUC of 0.96, sensitivity of 73%, and specificity of 100% for AFP-negative patients, whereas the AUC was 0.86 with sensitivity of 53% and specificity of 100% for AFP-positive patients. Furthermore, the rates of the selected mutations were significantly greater in recurrent HCC than in non-recurrent HCC (P<0.05). Conclusions: This study has identified a novel panel of somatic mutations, and detection of the mutations in plasma cfDNA shows good diagnostic performance. Therefore, this approach holds promise as a novel tool for diagnosing HCC.

The tumor suppressor DLC1 inhibits cancer progression and oncogenic autophagy in hepatocellular carcinoma.

Downregulation of deleted in liver cancer 1 (DLC1) is associated with poor prognosis of various cancers, but its functional mechanisms in hepatocellular carcinoma (HCC) remains unclear. In the present study, we investigated the roles of DLC1 in tumor progression and autophagy of HCC. We found that DLC1 was frequently downregulated in HCC tissues. Underexpression of DLC1 correlated with AFP level, vascular invasion, poor differentiation, and poor prognosis. In vitro assays revealed that DLC1 not only suppressed the proliferation, migration, and invasion of HCC cells, but also inhibited autophagy of HCC cells. Mechanistic investigation revealed that DLC1 decreased TCF4 expression and the interaction between ß-catenin and TCF4, then inactivated Wnt/ß-catenin signaling. Additionally, DLC1 suppressed the ROCK1 activity and the dissociation of the Beclin1-Bcl2 complex, thereby inhibiting autophagy of HCC cells. In conclusion, our findings imply that loss of DLC1 contributes to the progression and oncogenic autophagy of HCC.

Long Noncoding RNA HCAL Facilitates the Growth and Metastasis of Hepatocellular Carcinoma by Acting as a ceRNA of LAPTM4B.

Long noncoding RNAs (lncRNAs) are a new class of regulatory noncoding RNAs. Emerging evidences indicate that lncRNAs play a critical role in the development of hepatocellular carcinoma (HCC). Although several lncRNAs have been annotated, the association of most lncRNAs with HCC is unknown. In this study, we investigated lncRNA alterations in HCC by performing lncRNA microarray analysis. We identified a novel lncRNA called HCC-associated lncRNA (HCAL) that was highly expressed in HCC tissues. HCAL upregulation was clinically associated with poor differentiation, intravascular cancer embolus, and decreased survival of patients with HCC. HCAL silencing significantly inhibited the growth and metastasis of HCC cells both in vitro and in vivo. Interestingly, transcriptome-sequencing analysis of HCAL-knockdown cells showed alterations in some cancer-related pathways. Mechanistically, HCAL directly interacted with and functioned as a sponge for microRNAs such as miR-15a, miR-196a, and miR-196b to modulate LAPTM4B expression. Taken together, our findings suggest the presence of a novel lncRNA-miRNA-mRNA regulatory network, i.e., the HCAL-miR-15a/miR-196a/miR-196b-LAPTM4B network, in HCC and indicate that HCAL may be a potential target for treating HCC.

Natural killer cells inhibit pulmonary metastasis of hepatocellular carcinoma in nude mice.

Natural killer (NK) cells have been demonstrated to inhibit tumor growth. However, the role of NK cells in the inhibition of hepatocellular carcinoma metastasis is not well understood. The present study aimed to investigate the roles that NK cells may serve in inhibiting hepatocellular carcinoma metastasis. The role of isolated NK cells in the inhibition, proliferation, migration and invasion of the hepatoma cell line, MHCC97-H, was examined in vitro. Additionally, the survival rate of NK cells labeled with carboxyfluorescein diacetate-succinimidyl ester was assessed in vivo. An orthotopic implantation model was used to evaluate the role of NK cells in suppressing MHCC97-H cells in vivo. The effect of interleukin (IL)-2 stimulation on the tumor-inhibitory role of the NK cells was measured indirectly by analyzing the expression of various NK cell receptors and activated NK cell markers. It was observed that the NK cells inhibited the proliferation, migration and invasion of the MHCC97-H cells in vitro. Furthermore, the NK cells demonstrated long-term survival in the livers of the nude mice, and inhibited lung metastasis of hepatocellular carcinoma in vivo. However, liver tumor growth was not inhibited by the NK cells. IL-2 was identified to enhance the tumor-inhibitory effect of NK cells. The present study concludes that IL-2 may enhance the antitumor activity of the NK cells, and thereby inhibit the metastases of hepatocellular carcinoma in mice.

Mutual regulation between CHD5 and EZH2 in hepatocellular carcinoma.

Chromodomain helicase DNA binding protein 5 (CHD5) acts as a tumor suppressor in many cancers. In the present study, we demonstrated that reduced levels of CHD5 in hepatocellular carcinoma (HCC) tissues were significantly associated with metastasis and poor prognosis. Gain-of-function assays revealed that CHD5 suppressed motility and invasion of HCC cells. Subsequent investigations showed that CHD5 was epigenetically silenced by polycomb repressive complex 2 (PRC2)-mediated the trimethylation of histone H3 at lysine 27 (H3K27me3) in HCC cells. Furthermore, overexpression of CHD5 repressed enhancer of zeste homolog 2 (EZH2) and activated PRC2 target genes, such as p16 and p21. Chromatin immunoprecipitation and luciferase reporter assays also showed that CHD5 and EZH2 bind to each other's promoters and inhibit transcription. These findings uncovered, for the first time, a mutual suppression regulation between CHD5 and EZH2, which may provide new insights into their potential therapeutic significance for HCC.

Ex vivo hepatectomy and partial liver autotransplantation for hepatoid adenocarcinoma: A case report.

We previously reported the case of a 56-year-old male who underwent surgical treatment for gastric hepatoid adenocarcinoma and splenic metastasis. The present study reports the case of the same patient who underwent successful ex vivo hepatectomy and partial liver autotransplantation. Computed tomography scans demonstrated that the tumor was located in the left and caudate lobes of the liver, with hepatic vein and inferior vena cava involvement, and right portal vein compression. To clarify the association between the vessels and the tumor, a three-dimensional imaging technique was used to reconstruct the liver architecture. During the surgery, the whole liver was removed with the retrohepatic vena cava, which was replaced with a prosthetic graft without a veno-venous bypass; a portacaval shunt for the anhepatic phase was performed simultaneously. The surgery lasted 9 h, and the anhepatic phase lasted 4 h. Blood loss during the surgery was recorded at 1,500 ml. The time taken for recovery was 21 days post-surgery, and at 20 months, the patient was disease-free. To the best of our knowledge, this is the first case of ex vivo liver resection performed for hepatic metastasis of hepatoid adenocarcinoma to be reported.

Significance of genetic variants in DLC1 and their association with hepatocellular carcinoma.

DLC1 has been shown to be downregulated or absent in hepatocellular carcinoma (HCC) and is associated with tumorigenesis and development. However, only a small number of studies have focused on genetic variations of DLC1. The present study performed exon sequencing for the DLC1 gene in HCC tissue samples from 105 patients to identify functional genetic variation of DLC1 and its association with HCC susceptibility, clinicopathological features and prognosis. A novel missense mutation and four non­synonymous single nucleotide polymorphisms (SNPs; rs3816748, rs11203495, rs3816747 and rs532841) were identified. A significant correlation of rs3816747 polymorphisms with HCC susceptibility was identified. Compared to individuals with the GG genotype of rs3816747, those with the GA (odds ratio (OR)=0.486; P=0.037) or GA+AA genotype (OR=0.51; P=0.039) were associated with a significantly decreased HCC risk. Furthermore, patients with the GC+CC genotype of rs3816748, the TC+CC genotype of rs11203495 or the GA+AA genotype of rs3816747 had small­sized tumors compared with those carrying the wild­type genotype. No significant association of DLC1 SNPs with the patients' prognosis was found. These results indicated that genetic variations in the DLC1 gene may confer a risk for HCC.

Integrated analysis of gene expression and DNA methylation changes induced by hepatocyte growth factor in human hepatocytes.

Hepatocellular carcinoma (HCC) is the one of most common malignant tumors. The tumor microenvironment has a role in not only supporting growth and survival of tumor cells, but also triggering tumor recurrence and metastasis. Hepatocyte growth factor (HGF), one of the important growth factors in the tumor microenvironment, has an important role in angiogenesis, tumorigenesis and regeneration. However, the exact mechanism by which HGF regulates HCC initiation and development via epigenetic reprogramming has remained elusive. The present study focused on the epigenetic modification and target tumor-suppressive genes of HGF treatment in HCC. Expression profiling and DNA methylation array were performed to investigate the function of HGF and examine global genomic DNA methylation changes, respectively. Integrated analysis of gene expression and DNA methylation revealed potential tumor suppressor genes (TSGs) in HCC. The present study showed the multiple functions of HGF in tumorous and non­tumorous pathways and global genomic DNA methylation changes. HGF treatment upregulated the expression of DNA methyltransferase 1 (DNMT1). Overexpression of DNMT1 in HCC patients correlated with the malignant potential and poor prognosis of HCC. Furthermore, integration analysis of gene expression and DNA methylation changes revealed novel potential tumor suppressor genes TSGs including MYOCD, PANX2 and LHX9. The present study has provided mechanistic insight into epigenetic repression of TSGs through HGF­induced DNA hypermethylation.

Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy.

Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA.

Expression pattern and clinicopathologic significance of NKD1 in human primary hepatocellular carcinoma.

It has been reported that NKD1 was an antagonist of the canonical Wnt/ß-catenin pathway. While there is little information regarding NKD1 expression pattern in human hepatocellular carcinoma (HCC). The aim of this study was to investigate the clinicopathologic significance and expression pattern of NKD1 in HCC. NKD1 protein expressions in 69 paired HCC cancer/adjacent non-cancerous tissues were detected by Western blot. Immunohistochemical studies were performed on 58 cases of HCC with integrated clinical information. NKD1 protein expression was divided into normal and low expression group and correlations between NKD1 protein expression and clinicopathologic factors were then evaluated. Western blot results showed that NKD1 protein levels were significantly lower in cancerous tissues compared with corresponding normal tissue (p < 0.05). In addition, we found that the level of NKD1 protein expression in HCC was significantly associated with tumor size (p = 0.011), intra or extra-hepatic metastasis (p = 0.010) and differentiation (p = 0.003). This is to our knowledge the first report investigating NKD1 protein expression pattern in HCC. Our data show that decreased NKD1 protein expression is associated with clinicopathologic factors, and suggest that NKD1 may play an important role in the development of HCC and could serve as a novel biomarker for HCC after further investigation.

Mechanistic and biological significance of DNA methyltransferase 1 upregulated by growth factors in human hepatocellular carcinoma.

Dysregulation of growth factor signaling plays a pivotal role in controlling the malignancy phenotype and progression of hepatocellular carcinoma (HCC). However, the precise oncogenic mechanisms underlying transcription regulation of certain tumor suppressor genes (TSGs) by growth factors are poorly understood. In the present study, we report a novel insulin-like growth factor 1 (IGF1) pathway that mediates de novo DNA methylation and TSG (such as DLC1 and CHD5) silencing by upregulation of the DNA methyltransferase 1 (DNMT1) via an AKT/ß-transducin repeat-containing protein (ßTrCP)-mediated ubiquitin-proteasome pathway in HCC. Analysis of DNA methylation in CpG islands of target genes revealed high co-localization of DNMT1 and DNMT3B on the promoters of TSGs associated with enhanced CpG hypermethylation. Our results point to a novel epigenetic mechanism for growth factor-mediated repression of TSG transcription that involves DNA methylation.