Chuan Lin

Human CD14+CTLA‐4+ regulatory dendritic cells suppress T‐cell response by cytotoxic T‐lymphocyte antigen‐4‐dependent IL‐10 and indoleamine‐2,3‐dioxygenase production in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with limited therapeutic options. HCC‐induced immunosuppression often leads to ineffectiveness of immuno‐promoting therapies. Currently, suppressing the suppressors has become the potential strategy for cancer immunotherapy. So, figuring out the immunosuppressive mechanisms induced and employed by HCC will be helpful to the design and application of HCC immunotherapy. Here, we identified one new subset of human CD14+CTLA‐4+ regulatory dendritic cells (CD14+DCs) in HCC patients, representing ∼13% of peripheral blood mononuclear cells. CD14+DCs significantly suppress T‐cell response in vitro through interleukin (IL)‐10 and indoleamine‐2,3‐dioxygenase (IDO). Unexpectedly, CD14+DCs expressed high levels of cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) and programmed death‐1, and CTLA‐4 was found to be essential to IL‐10 and IDO production. So, we identified a novel human tumor‐induced regulatory DC subset, which suppresses antitumor immune response through CTLA‐4‐dependent IL‐10 and IDO production, thus indicating the important role of nonregulatory T‐cell‐derived CTLA‐4 in tumor‐immune escape or immunosuppression. Conclusions: These data outline one mechanism for HCC to induce systemic immunosuppression by expanding CD14+DCs, which may contribute to HCC progression. This adds new insight to the mechanism for HCC‐induced immunosuppression and may also provide a previously unrecognized target of immunotherapy for HCC. (Hepatology 2014;59:567–579)

High viral load is associated with poor overall and recurrence-free survival of hepatitis B virus-related hepatocellular carcinoma after curative resection: A prospective cohort study

PURPOSE The aim of this prospective cohort study was to investigate the impact of preoperative hepatitis B viral load, as well as postoperative antiviral therapy, on the risk of long-term survival after curative resection of hepatitis B virus-related hepatocellular carcinoma (HCC). METHODS A prospective cohort of hepatitis B virus-related HCC patients undergoing curative resection from 2002 to 2008 was studied. According to preoperative viral load (using 10,000 copies/mL of hepatitis B virus DNA level as cut-off value), two groups were compared. Prognostic factors for overall survival and recurrence-free survival were evaluated. Additionally, subgroup analysis was conducted in patients with high viral load to investigate prediction of postoperative antiviral therapy on the long-term prognosis. RESULTS With a median follow-up of 49.1 months, patients with high viral load had lower median overall survival (78.3 months vs. 111.4 months, P<0.001) and RFS (44.6 months vs. 94.8 months, P<0.001) compared with those with low viral load. Multivariate analysis revealed that preoperative high viral load was an independent risk factor affecting both overall survival and recurrence-free survival (both P<0.001). The subgroup analysis revealed that postoperative antiviral therapy independently improved recurrence-free survival for patients with high viral load (P=0.001). CONCLUSIONS Hepatitis B virus-related HCC patients with preoperative high viral load led to poorer overall and recurrence-free survival than those with low viral load after curative resection. To prevent postoperative recurrence, antiviral therapy should be initiated in those patients with hepatitis B virus DNA ≥ 10,000 copies/ml.

Krüppel-Like Factor 8 Is a New Wnt/Beta-Catenin Signaling Target Gene and Regulator in Hepatocellular Carcinoma

Krüppel-like factor 8 (KLF8) plays important role in cell cycle and oncogenic transformation. Here we report the mechanisms by which KLF8 crosstalks with Wnt/β-catenin signaling pathway and regulates hepatocellular carcinoma (HCC) cells proliferation. We show that overexpression of KLF8 and nucleus accumulation of β-catenin in the human HCC samples are positively correlated. More importantly, KLF8 protein levels plus nucleus accumulation of β-catenin levels were significantly elevated in high-grade HCC compared to low-grade HCC. Using HCC HepG2 cells we find that, on the one hand both protein and mRNA of KLF8 are up-regulated under Wnt3a stimulation, on the other hand overexpression of KLF8 increases the cytoplasm and nucleus accumulation of β-catenin, recruits p300 to β-catenin/T-cell factor 4 (TCF4) transcription complex, enhances TOP flash report gene transcription, and induces Wnt/β-catenin signaling target genes c-Myc, cyclin D1 and Axin1 expression. Knockdown of KLF8 using shRNA inhibits Wnt3a induced transcription of TOP flash report gene and expression of c-Myc, cyclin D1 and Axin1. Knockdown of β-catenin by shRNA rescues the enhanced HepG2 and Hep3B cells proliferation ability induced by overexpression of KLF8.

Double-negative feedback loop between microRNA-422a and forkhead box (FOX)G1/Q1/E1 regulates hepatocellular carcinoma tumor growth and metastasis.

Growing evidence indicates that the aberrant expression of microRNAs (miRNAs) contributes to tumor development; however, the function of miRNAs in human hepatocellular carcinoma (HCC) remains largely undefined. In this study, we report that microRNA‐422a (miR‐422a) is significantly down‐regulated in HCC tumor samples and cell lines compared with normal controls, and its expression level is negatively correlated with pathological grading, recurrence, and metastasis. The restoration of miR‐422a expression in HCC tumor cells significantly inhibited cell proliferation and migration in vitro. At the same time, the overexpression of miR‐422a in HCC tumor cells significantly inhibits tumor growth and liver metastasis in xenograft tumor models. A mechanistic study identified three genes, forkhead box G1 (FOXG1), FOXQ1, and FOXE1, as miR‐422a targets in the regulation of HCC development. We also investigated the function of the three targets themselves in HCC tumorigenesis using RNAi manipulation and demonstrated that the knockdown of these targets led to significant inhibition of tumor cell proliferation and migration both in vitro and in vivo. More interestingly, a potential miR‐422a promoter region was identified. Both the promoter activity and miR‐422a expression were negatively regulated by the three targets, indicating that a double‐negative feedback loop exists between miR‐422a and its targets. Moreover, we explored the therapeutic potential of miR‐422a in HCC treatment and found that the therapeutic delivery of miR‐422a significantly inhibited tumor development in a xenograft tumor model and a diethylnitrosamine‐induced primary HCC model. Conclusion: Our findings show the critical roles of miR‐422a and its targets—FOXG1, FOXQ1, and FOXE1—in the regulation of HCC development and provide new potential candidates for HCC therapy. (Hepatology 2015;61:561‐573)

Genomic and oncogenic preference of HBV integration in hepatocellular carcinoma

Hepatitis B virus (HBV) can integrate into the human genome, contributing to genomic instability and hepatocarcinogenesis. Here by conducting high-throughput viral integration detection and RNA sequencing, we identify 4,225 HBV integration events in tumour and adjacent non-tumour samples from 426 patients with HCC. We show that HBV is prone to integrate into rare fragile sites and functional genomic regions including CpG islands. We observe a distinct pattern in the preferential sites of HBV integration between tumour and non-tumour tissues. HBV insertional sites are significantly enriched in the proximity of telomeres in tumours. Recurrent HBV target genes are identified with few that overlap. The overall HBV integration frequency is much higher in tumour genomes of males than in females, with a significant enrichment of integration into chromosome 17. Furthermore, a cirrhosis-dependent HBV integration pattern is observed, affecting distinct targeted genes. Our data suggest that HBV integration has a high potential to drive oncogenic transformation.

Ligand-Directed Stearic Acid Grafted Chitosan Micelles to Increase Therapeutic Efficacy in Hepatic Cancer

Targeted delivery system would be an interesting platform to enhance the therapeutic effect and to reduce the side effects of anticancer drugs. In this study, we have developed lactobionic acid (LA)-modified chitosan-stearic acid (CS-SA) (CSS-LA) to deliver doxorubicin (DOX) to hepatic cancer cells. The average particle size of CSS-LA/DOX was ∼100 nm with a high entrapment efficiency of >95%. Drug release studies showed that DOX release from pH-sensitive micelles is significantly faster at pH 5.0 than at pH 7.4. The LA conjugated micelles showed enhanced cellular uptake in HepG2 and BEL-7402 liver cancer cells than free drug and unconjugated micelles. Consistently, CSS-LA/DOX showed enhanced cell cytotoxicity in these two cell lines. Annexin-V/FITC and PI based apoptosis assay showed that the number of living cells greatly reduced in this group with marked presence of necrotic and apoptotic cells. LA-conjugated carrier induced typical chromatic condensation of cells; membrane blebbing and apoptotic bodies began to appear. In vivo, CSS-LA/DOX showed an excellent tumor regression profile with no toxic side effects. The active targeting moiety, long circulation profile, and EPR effect contributed to its superior anticancer effect in HepG2 based tumor. Our results showed that polymeric micelles conjugated with LA increased the therapeutic availability of DOX in the liver cancer cell based solid tumor without any toxic side effects. The active targeting ligand conjugated nanoparticulate system could be a promising therapeutic strategy in the treatment of hepatic cancers.

Pioglitazone, a PPARγ agonist, inhibits growth and invasion of human hepatocellular carcinoma via blockade of the rage signaling.

Pioglitazone (PGZ), a synthetic PPARγ ligand, is known to have anti‐tumor activity. However, it is unclear how it acts against hepatocellular carcinoma (HCC). We hypothesized that the pathological receptor for advanced glycation end products (RAGE) is involved in the PGZ anti‐tumor process. To test this notion, human primary HCC tissues and corresponding adjacent non‐cancerous tissues (ANCT) from 75 consecutive cases were analyzed. The expression and clinical significance of RAGE was assessed by immunohistochemical assay through tissue microarray. After HCC cells were pretreated with different concentrations of PGZ, cell proliferation, apoptosis, cell invasion, and cell cycle distribution were evaluated by multiple assays. The results showed that, the positive expression of RAGE was significantly higher in HCC tissues than in ANCT (66.7% vs. 36.0%, P < 0.001), and was closely associated with pathological staging (P = 0.014) and lymph‐vascular space invasion (P = 0.003). Moreover, PGZ inhibited proliferative activity and invasive potential, and induced apoptosis and cell cycle arrest in HCC cells resulting in increased expression of PPARγ and decreased expression of RAGE, NF‐κB, HMGB1, p38MAPK, Ki‐67, MMP‐2, and CyclinD1. Furthermore, knockdown of RAGE or NF‐κB by siRNA effectively suppressed cell proliferation and invasion, and mediated the inhibitory effects of PGZ in HCC cells. Taken together, our findings suggest that, RAGE is overexpressed in human HCC tissues, and is closely associated with the pathological staging and tumor invasion of HCC. In addition, PGZ as a PPARγ agonist may inhibit growth and invasion of HCC cells via blockade of the RAGE signaling.

Concomitant lung metastasis in patients with advanced hepatocellular carcinoma

AIM To investigate the clinical features and prognostic factors of advanced hepatocellular carcinoma (HCC) patients presenting with lung metastasis at initial diagnosis. METHODS Between 2001 and 2010, we recruited 76 consecutive HCC patients initially presenting with lung metastasis, without co-existing metastasis from other sites. These patients were divided into three groups: untreated group (n = 22), single treatment group (n = 19), and combined treatment group (n = 35). RESULTS Metastasis of bilateral lung lobes was common and noted in 35 patients (46.1%), and most of patients (59/76, 77.6%) presented with multiple lung metastatic nodules. Nineteen patients (25.0%) received single-method treatment, including hepatectomy in 4, transcatheter arterial chemoembolization in 6, radiotherapy in 5, and oral sorafenib in 4. Thirty-five patients (46.1%) received combined treatment modalities. The overall median survival of the all patients was 8.7 ± 0.6 mo; 4.1 ± 0.3, 6.3 ± 2.5 and 18.6 ± 3.9 mo, respectively in the untreated group, single treatment group and combined treatment group, respectively, with a significant difference (log-rank test, P < 0.001). Multivariate analysis revealed that Child-Pugh score, the absence or presence of portal vein tumor thrombus, and treatment modality were three independent prognostic factors affecting survival of patients with advanced HCC and concomitant lung metastasis. CONCLUSION Combined treatment modalities tend to result in a better survival as compared with the conservative treatment or single treatment modality for HCC patients initially presenting with lung metastasis.

Zinc finger protein X-linked promotes expansion of EpCAM+ cancer stem-like cells in hepatocellular carcinoma

Zinc finger protein X‐linked (ZFX) is frequently upregulated in multiple human malignancies and also plays a critical role in the maintenance of self‐renewal in embryonic stem cells. However, the role of ZFX in liver cancer stem cells (CSCs) remains obscure. We observed that the elevated expression of both ZFX and epithelial cell adhesion molecule (EpCAM) was associated with aggressive clinicopathological features and indicated poor prognosis in patients with hepatocellular carcinoma (HCC). ZFX was commonly enriched in liver EpCAM+ CSCs. Knockdown of ZFX decreased the proportion of EpCAM+ CSCs in HCC cells and suppressed their expression of stemness‐related genes, self‐renewal capacity, chemoresistance, metastatic potential, and tumorigenicity. Conversely, upregulation of ZFX in CSCs rescued these inhibitory effects and enhanced stem‐like properties. Mechanistically, depletion of ZFX reduced nuclear translocation and transactivation of β‐catenin, thereby inhibiting the self‐renewal capacity of EpCAM+ CSCs. Moreover, knockdown of β‐catenin attenuated the self‐renewal of EpCAM+ HCC cells stably expressing ZFX, further indicating that β‐catenin is required for ZFX‐mediated expansion and maintenance of EpCAM+ CSCs. Taken together, our findings indicate that ZFX activates and maintains EpCAM+ liver CSCs by promoting nuclear translocation and transactivation of β‐catenin. Furthermore, combination of ZFX and EpCAM may serve as a significant indicator for prognosis of patients with HCC.

Hepatitis B virus X protein promotes the stem-like properties of OV6 + cancer cells in hepatocellular carcinoma

Hepatitis B virus X protein (HBx) and cancer stem-like cells (CSCs) have both been implicated in the occurrence and development of HBV-related hepatocellular carcinoma (HCC). However, whether HBx contributes to the stem-like properties of OV6+ CSCs in HCC remains elusive. In this study, we showed that the concomitant expression of HBx and OV6 was closely associated with the clinical outcomes and prognosis of patients with HBV-related HCC. HBx was required for the stem-like properties of OV6+ liver CSCs, including self-renewal, stem cell-associated gene expression, tumorigenicity and chemoresistance. Mechanistically, HBx enhanced expression of MDM2 by directly binding with MDM2 and inhibiting its ubiquitin-directed self-degradation. MDM2 translocation into the nucleus was also upregulated by HBx and resulted in enhanced transcriptional activity and expression of CXCL12 and CXCR4 independent of p53. This change in expression activated the Wnt/β-catenin pathway and promoted the stem-like properties of OV6+ liver CSCs. Furthermore, we observed that the expression of any two indicators from the HBx/MDM2/CXCR4/OV6 axis in HCC biopsies could predict the prognosis of patients with HBV-related HCC. Taken together, our findings indicate the functional role of HBx in regulating the stem-like properties of OV6+ CSCs in HCC through the MDM2/CXCL12/CXCR4/β-catenin signaling axis, and identify HBx, MDM2, CXCR4 and OV6 as a novel prognostic pathway and potential therapeutic targets for patients with HBV-related HCC patients.