Gene- and immunotherapy for hepatocellular carcinoma

Puerarin alleviates liver fibrosis via inhibition of the ERK1/2 signaling pathway in thioacetamide-induced hepatic fibrosis in rats

Liver fibrosis is a complex pathological process and an early step in the progression of liver cirrhosis, which can eventually develop into hepatocellular carcinoma. Currently, there is no effective treatment for liver fibrosis. Puerarin is a traditional Chinese herb, which is commonly used in the treatment of various diseases. In addition, it is also believed to have a therapeutic effect in liver fibrosis. However, whether puerarin reduces liver fibrosis via the ERK1/2 signaling pathway to inhibit the activation of hepatic stellate cell (HSC) and excessive collagen deposition in liver fibrosis remains unknown. The aim of the current study was to establish a liver fibrosis in vivo model by intraperitoneal injection of thioacetamide (TAA) and investigate the effect of puerarin in the treatment of liver fibrosis. Hematoxylin and eosin and Van Gieson's staining were used to examine histopathological changes associated with liver fibrosis. Liver hydroxyproline content was examined to determine the total amount of collagen in the liver. The relative protein expression levels of transforming growth factor β1 (TGFβ1), α-smooth muscle actin (α-SMA), collagen type I, fibronectin, ERK1/2 and p-ERK1/2 were determined by western blot analysis. In the TAA group, histopathological changes and collagen fiber content in rat liver tissue samples were significantly increased compared with the control group (P<0.05). In addition, treatment with puerarin significantly decreased histopathological changes and collagen fiber content in rat liver tissue samples (P<0.05). The relative protein expression levels of TGFβ1, α-SMA, collagen type I, fibronectin and p-ERK1/2 were significantly upregulated in the TAA group compared with the control group (P<0.05), whereas puerarin treatment reversed these changes. These findings suggest that treatment with puerarin may reduce HSC activation and alleviate extracellular matrix protein expression levels by inhibiting the TGF-β/ERK1/2 pathway in liver fibrosis.

Oncogene RPA1 promotes proliferation of hepatocellular carcinoma via CDK4/Cyclin-D pathway

As the sixth most prevalent cancer, hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Human replication protein A (RPA), a three-subunit protein, plays a central role in eukaryotic DNA replication, homologous recombination, and excision repair, including RPA1, RPA2 and RPA3. Recently, some studies focusing on the relation between RPA1 and carcinogenesis have demonstrated that RPA1 is a candidate oncogene and influences tumor biological behaviors in many cancers such as esophageal carcinoma, colon cancer, urothelial carcinomas, etc. However, the characteristic role of RPA1 in HCC and the detailed potential mechanism remain unknown. To identify the real effects of RPA1 on HCC and its potential pathway participating in the changes of liver cancer cells, we have conducted this study and demonstrated that RPA1 is up-regulated both in liver cancer cell lines and HCC tissues, which is associated with poorer prognosis, advanced TNM stage and larger tumor size. Stable knock-down of RPA1 by specific small hairpin RNA (shRNA) contributes to the impaired proliferate ability of SK-HEP-1 cells both in vitro and vivo. Consistently, upregulation of RPA1 in HuH-7 cells by specific adenovirus promotes tumor cells' proliferation. Furthermore, cyclin-dependent-kinase 4(CDK4)/Cyclin-D pathway is found to be well associated with RPA1 induced proliferation. In conclusion, RPA1 plays a pivotal role as a potential oncogene in HCC and promotes tumor proliferation via CDK4/Cyclin-D pathway.

Radiofrequency hyperthermia-enhanced herpes simplex virus-thymidine kinase/ganciclovir direct intratumoral gene therapy of hepatocellular carcinoma

PURPOSE

To determine the feasibility of using radiofrequency hyperthermia (RFH) and to enhance the therapeutic effect of herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) for the treatment of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Human HCC cells (HepG2) were first transfected with lentivirus/luciferase. For both in vitro confirmation and in vivo validation, luciferase-labeled HCC cells and HCC tumour xenografts on mice received different treatments: (i) combination therapy of intratumoral HSV-TK/GCV-mediated gene therapy plus magnetic resonance imaging heating guidewire (MRIHG)-mediated RFH; (ii) gene therapy only; (iii) RFH only; and (iv) phosphate-buffered saline (PBS) as control. Cell proliferation was quantified. Tumour changes were monitored by ultrasound imaging and bioluminescence optical imaging before and at days 7 and 14 after treatments, which were correlated with subsequent histology.

RESULTS

In vitro, the lowest cell proliferation was seen in the combination therapy group compared with control groups (29 ± 6% vs. 56 ± 9%, 93 ± 4%, and 100 ± 5%, p < .05). Ultrasound imaging of treated animal xenografts showed smaller relative tumour volume in combination therapy group than those in three control groups (0.74 ± 0.19 vs. 1.79 ± 0.24, 3.14 ± 0.49 and 3.22 ± 0.52, p < .05). Optical imaging demonstrated significant decrease of bioluminescence signals of tumours in the combination therapy group, compared to those in three control groups (1.2 ± 0.1 vs. 1.9 ± 0.2% vs. 3.3 ± 0.6% vs. 3.5 ± 0.4%, p < .05). These imaging findings were correlated well with histologic confirmation.

CONCLUSION

RFH can enhance HSV-TK/GCV-mediated gene therapy of HepG2 cell line and mice human HCC xenografts, which may open new avenues for effective management of HCC using MR/RFH integrated interventional gene therapy.

BCL6B expression in hepatocellular carcinoma and its efficacy in the inhibition of liver damage and fibrogenesis

B cell CLL/lymphoma 6 member B (BCL6B) is expressed in many normal tissues but expressed at very low levels in cancer tissues. It was reported that BCL6B inhibits hepatocellular carcinoma (HCC) metastases, but the exact role of BCL6B in HCC remains to be investigated. BCL6B expression was significantly decreased in HCC tissues compared with paired non-cancer tissues. Low BCL6B expression in tumors was correlated with shorter overall survival in patients, and multivariate Cox regression analysis revealed that BCL6B expression was an independent prognostic factor for human HCC patients. Moreover, a positive correlation between BCL6B expression and hepatic cirrhosis was found in an analysis of HCC clinicopathological characteristics. BCL6B expression was increased in rat fibrotic liver samples in response to liver injury. BCL6B transgenic rats were less susceptible to hepatocellular damage, inflammation and fibrosis. In vitro studies demonstrated that BCL6B inhibited the activation of hepatic stellate cells though upregulation of hepatocyte growth factor. In addition, transcriptomic microarray analysis was performed to explore the mechanisms in which BCL6B confers protection from tumorigenesis. In conclusion, BCL6B plays a pivotal role as a prognostic biomarker for HCC, and the restoration of BCL6B may be a novel strategy as an anti-fibrogenic therapy for human HCC.

Antitumor efficacy of C-X-C motif chemokine ligand 14 in hepatocellular carcinoma in vitro and in vivo

C-X-C motif chemokine ligand 14 (CXCL14) is a novel gene that is expressed in many normal cells but is absent from or expressed at very low levels in cancerous tissues such as head and neck squamous cell carcinoma (HNSCC), prostate cancer, and pancreatic cancer. However, the relationship between CXCL14 and hepatocellular carcinoma (HCC) remains unclear. Therefore, the exact function of CXCL14, which may modulate antitumor immune responses in certain cancers, was evaluated. CXCL14 was downregulated in HCC tissues compared to adjacent normal tissues. Moreover, overexpression of CXCL14 had an inhibitory effect on cell proliferation, induced apoptosis and inhibited the invasion of HCC cells in vitro. Upregulation of CXCL14 by lentivirus also significantly suppressed the growth of subcutaneous tumors in nude mice in vivo. We further demonstrated that the loss of CXCL14 expression was regulated by promoter hypermethylation. CXCL14 induced tumor cell apoptosis through both the mitochondrial and nuclear apoptosis pathways. CXCL14 suppressed tumor cell proliferation through regulation of the cell cycle by downregulation of cyclins and cyclin-dependent kinases. In conclusion, CXCL14 plays a pivotal role as a potential tumor suppressor in HCC. The re-expression or upregulation of this gene may provide a novel strategy in HCC therapy in the future.

Immunotherapy by autologous dendritic cell vaccine in patients with advanced HCC

BACKGROUND

Dendritic cells (DCs) could be used as potential cellular adjuvant for the production of specific tumor vaccines.

OBJECTIVES

Our study was aimed to evaluate the safety and efficacy of autologous pulsed DC vaccine in advanced hepatocellular carcinoma (HCC) patients in comparison with supportive treatment.

METHODS

Thirty patients with advanced HCC not suitable for radical or loco-regional therapies were enrolled. Patients were divided into 2 groups, group I consisted of 15 patients received I.D vaccination with mature autologous DCs pulsed ex vivo with a liver tumor cell line lysate. Group II (control group, no. 15) received supportive treatment. One hundred and 4 ml of venous blood were obtained from each patient to generate DCs. DCs were identified by CD80, CD83, CD86 and HLA-DR expressions using flow cytometry. Follow up at 3, and 6 months post injection by clinical, radiological and laboratory assessment was done.

RESULTS

Improvement in overall survival was observed. Partial radiological response was obtained in 2 patients (13.3 %), stable course in 9 patients (60 %) and 4 patients (26.7 %) showed progressive disease (died at 4 months post-injection). Both CD8(+) T cells and serum interferon gamma were elevated after DCs injection.

CONCLUSION

Autologous DC vaccination in advanced HCC patients is safe and well tolerated.

Dendritic cell-based vaccines positively impact natural killer and regulatory T cells in hepatocellular carcinoma patients

Immunotherapy of cancer must promote antitumor effector cells for tumor eradication as well as counteract immunoregulatory mechanisms which inhibit effectors. Immunologic therapies of cancer are showing promise, including dendritic cell-(DC-) based strategies. DC are highly malleable antigen-presenting cells which can promote potent antitumor immunity as well as tolerance, depending on the environmental signals received. Previously, we tested a peptide-pulsed DC vaccine to promote Alpha-fetoprotein (AFP-) specific anti-tumor immunity in patients with hepatocellular carcinoma (HCC), and reported on the CD8⁺ T cell responses induced by this vaccine and the clinical trial results. Here, we show that the peptide-loaded DC enhanced NK cell activation and decreased regulatory T cells (Treg) frequencies in vaccinated HCC patients. We also extend these data by testing several forms of DC vaccines in vitro to determine the impact of antigen loading and maturation signals on both NK cells and Treg from healthy donors and HCC patients.

Genomic and proteomic biomarkers for diagnosis and prognosis of hepatocellular carcinoma

Hepatocellular carcinoma is one of the most deadly liver malignancies found worldwide, with hepatitis virus infection being the prominent risk factor for this lesion. Patients with hepatocellular carcinoma are usually first diagnosed when in the advanced stage; thus, long-term clinical outcomes are poor and patients have limited treatment options. Currently, surveillance of hepatocellular carcinoma relies upon serological testing of alpha-fetoprotein levels and hepatic ultrasonography, which have low sensitivity and specificity, and are sometimes operator-dependent, respectively. Therefore, discovery of new biomarkers for early and accurate detection of hepatocellular carcinoma would be of great clinical value. Genomic and proteomic approaches are two major laboratory platforms for the identification of candidate hepatocellular carcinoma biomarkers based on profiling and validating with tumor and nontumor clinical samples. Frequently, these diagnostic markers have been found in association with genetic aberrations, protein-level alterations, post-translational modifications and immune functions. With the discovery of these biomarkers, earlier detection of hepatocellular carcinoma in high-risk subjects (e.g., cirrhosis and hepatitis carriers) becomes possible, which will enable clinicians to offer patients better clinical management and more effective treatment modalities.

Alpha-fetoprotein and other tumour-associated antigens for immunotherapy of hepatocellular cancer

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer death, with few treatment options for advanced disease.

OBJECTIVES

Here, we review the aetiology of HCC and focus on recent data on tumour-associated antigens (TAA) for HCC, their functions and potential use as immunological targets for immune-based therapy for HCC. In addition, we examine some aspects of antigen presentation within the liver.

RESULTS/CONCLUSIONS

alpha-Fetoprotein (AFP) has been investigated for many years as a TAA, and has been tested in recent clinical trials. More recently, additional TAA have been identified and new therapeutic approaches have been investigated which may be testable clinically in this difficult disease setting.

Treatment options for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is frequently diagnosed at advanced stages and has a high mortality rate. With improved survival of patients with cirrhotic liver disease and increased prevalence of chronic hepatitis C viral infections, a rise in the number of HCC cases is being reported worldwide. Early diagnosis and treatment can significantly improve the prognosis of patients with HCC. Although surgical resection is an important potentially curative therapy for liver tumors, in appropriately selected patients, liver transplantation has been shown to achieve excellent survival rates for a solid tumor. Locally ablative and locoregional therapies in the form of percutaneous ethanol injection, radiofrequency ablation, transcatheter arterial chemoembolization and transcatheter arterial radioembolization (TheraSphere) are viable options in patients with unresectable HCC. Unfortunately, the role of systemic therapy has been very limited in the treatment of these patients. Novel treatment options based on an improved understanding of the molecular pathogenesis of HCC are being explored. These targeted molecular therapies are aimed at growth factors and their receptors, intracellular signal transduction and cell cycle control. A substantial improvement in outcomes of intermediate and advanced stage HCC is expected with the advent of these targeted therapies, used in combination with surgical or locoregional therapies. Recent positive results from a large Phase III study of the receptor tyrosine kinase inhibitor, sorafenib, hold great promise in the treatment of HCC.

Vascular damage and anti-angiogenic effects of tumor vessel-targeted adenovirus-mediated herpes simplex virus thymidine kinase gene

AIM: To explore the therapeutic efficacy and mechanism of herpes simplex virus-thymidine kinase (HSV-tk) targeting angiogenesis against hepatocellular carcinoma in vivio and in vitro.

METHODS: Recombinant adenovirus containing kinase domain insert with receptor (KDR) or cytomegalovirus (CMV) promoter-controlled HSV-tk gene (AdKDR-tk and AdCMV-tk) was constructed using pAdeasy system. The expression of KDR antigen in human umbilical venous endothelial cells (HUVEC) and HepG2 was detected with histological analysis of cells. The virus was used to infect HUVEC and HepG2. Following administration of ganciclovir (GCV), the survival rate of gene-transfected HUVEC and HepG2 was evaluated by MTT method. To develop hepatocarcinomas in 32 Balb/C mice with HepG2 cells, the mice were divided into four groups: ganciclovir group (I), Ad group (II), AdCMV-tk group (III) and AdKDR-tk group (IV). Then selective administration of recombinant adenovirus or Ad via the intratumorial was given to all rats. Ganciclovir (GCV) was given at a dose of 100 mg·kg^-1·d^-1 (ip) started on the following day and lasted 10 d. Microvessel density (MVD) of tumor in all the treated animals were examined by the immunohistochemical methods and tumor burden was evaluated 10 d before and after the last GCV dose.

RESULTS: Immunocytochemical staining indicated the expression of KDR antigen in HUVEC. Under adenovirus infection index of 100, with increasing GCV concentration from 0 up to 50 mg/L, the survival rate of AdKDR-tk-transfected HUVEC and HepG2 decreased from 100% to (28.94 ± 5.67)% and (75.45 ± 2.91)% at proper order, respectively (P < 0.01), while the survival rate of AdCMV-tk-transfected HUVEC and HepG2 declined from 100% to (17.56 ± 2.48)% and (23.15 ± 5.72)%, respectively (P > 0.05). Compared with groupI, there was a decrease of tumor weight by 14.7% in group III and by 23.6% in group IV. And there was a distinct difference between group III and IV (P < 0.05). The median MVD for all groups was 37.4 ± 8.6, 30.6 ± 7.8, 27.6 ± 7.1, and 10.7 ± 4.1 (microvessels/mm²) in groupI, II, III and IV, respectively. And there was a marked difference between group III and II (P < 0.05), IV and II (P < 0.01), and IV and III (P < 0.01).

CONCLUSION: KDR promoter-HSV-tk gene may effectually restrain the growth of tumor via targeting angiogenesis for hepatocellular carcinoma with treatment of GCV.