Hepatocellular carcinoma

The EIIAPA chimeric promoter for tumor specific gene therapy of hepatoma

PURPOSE

For targeted imaging and therapy of hepatocellular carcinoma (HCC), we established a chimeric promoter (EIIAPA) containing alpha-fetoprotein (AFP) promoter and hepatitis B virus enhancer II (EIIA) to control downstream expression of reporter and therapeutic genes.

PROCEDURES

We combined AFP promoter and EIIA to establish a chimeric EIIAPA promoter, then developed a bi-cistronic plasmid vector containing HSV1-tk and luciferase genes controlled by EIIAPA to stably transfect HCC cells. The selective transcriptional activity of EIIAPA was assayed by bioluminescence imaging (BLI) and the function of EIIAPA was determined by in vivo microPET and BLI.

RESULTS

The luciferase expression driven by EIIAPA was higher than that driven by AFP promoter in HCC cell lines. EIIAPA-tk induced cytotoxicity was observed only in HepG2 cells. Accumulation of ¹³¹I-FIAU and bioluminescent signal were detected on HepG2 tumors but not in parental tumors. The HepG2 tumors derived from lentiviral-transduced EIIAPA-tk expressing cells accumulated ¹²⁴I-FIAU whereas the ARO tumors did not. The transfected HepG2 tumors expressed adequate EIIAPA-controlled HSV1-TK and the tumor regressed after ganciclovir treatment.

CONCLUSION

The chimeric EIIAPA is a potential candidate promoter for targeted imaging and gene therapy of HCC.

GHGKHKNK octapeptide (P-5m) inhibits metastasis of HCCLM3 cell lines via regulation of MMP-2 expression in in vitro and in vivo studies

P-5m, an octapeptide derived from domain 5 of HKa, was initially found to inhibit the invasion and migration of melanoma cells. The high metastatic potential of melanoma cells was prevented by the HGK motif in the P-5m peptide in vitro and in an experimental lung metastasis model, suggesting that P-5m may play an important role in the regulation of tumor metastasis. The aim of this study was to measure the effect of P-5m on tumor metastasis of human hepatocarcinoma cell line (HCCLM3) in vitro and in vivo in a nude mouse model of hepatocellular carcinoma (HCC), and detect the mechanisms involved in P-5m-induced anti-metastasis. By gelatin zymography, matrix metallo-proteinases 2 (MMP-2) activity in HCCLM3 was dramatically diminished by P-5m peptide. In addition, the migration and metastasis of HCCLM3 cells was also inhibited by the peptide in vitro. In an orthotopic model of HCC in nude mice, P-5m treatment effectively reduced the lung metastasis as well as the expression of MMP-2 in the tumor tissues. Overall, these observations indicate an important role for P-5m peptide in HCC invasion and metastasis, at least partially through modulation MMP-2 expression. These data suggests that P-5m may have therapeutic potential in metastatic human hepatocarcinoma.

Role of Twist in vasculogenic mimicry formation in hypoxic hepatocellular carcinoma cells in vitro

Vasculogenic mimicry (VM) refers to the unique ability of highly aggressive human tumor cells to form matrix-rich networks de novo when cultured on a three-dimensional matrix, thus mimicking embryonic vasculogenesis. Some studies have shown that tumor hypoxia can promote tumor cells to form vessel-like tubes in vitro and express genes associated with VM. Although, the mechanisms involved in hypoxia-induced VM remain elusive, we hypothesized that the epithelial-mesenchymal transition (EMT) regulator Twist may play a major role in hypoxia-induced VM. We investigated this hypothesis in vitro by pretreating hepatocellular carcinoma cells under hypoxic conditions. Following the hypoxia treatment, the cells formed typical pipe-like VM networks. Moreover, the expression of VM markers was increased. Hypoxia-induced VM was accompanied by the increased expression of Twist. Twist siRNA reversed the effects of hypoxia on VM. These results suggest that the overexpression of Twist correlates to hypoxia-induced VM in hepatocellular carcinoma cells.

Irinotecan-induced apoptosis is inhibited by increased P-glycoprotein expression and decreased p53 in human hepatocellular carcinoma cells

Irinotecan, a DNA topoisomerase I inhibitor, is widely used in cancer chemotherapy. However, little is known of the mechanisms of its antitumor effects and the development of drug resistance in human hepatocellular carcinoma (HCC). In this study, we investigated the effects of short-term culture with SN-38, the active metabolite of irinotecan, on apoptosis in Huh7 cells. The cells were cultured with SN-38 for 24, 72, and 120 h, and apoptosis was determined using the terminal dUTP nick-end labeling (TUNEL) assay. The expressions of p53, apoptosis-related proteins, and P-glycoprotein (P-gp), a protein conferring the multidrug-resistant phenotype, were analyzed using Western blotting. Induced expression of P-gp was detected using fluorescence microscopy. SN-38 significantly induced apoptosis in Huh7 cells at 24 h. SN-38 also increased the expression of p53, Bax, and caspase-9 and decreased Bcl-xL expression in Huh7 cells. SN-38 decreased p53 expression and increased P-gp expression after 120 h, resulting in inhibition of apoptosis. This inhibition was reversed by the addition of verapamil to the culture medium during 120 h incubation. SN-38-induced P-gp expression was additionally enhanced by p53 decoy oligodeoxynucleotide. The changes in P-gp expression were directly moderated by p53 gene downregulation, suggesting that it plays a role in the mechanism of drug resistance. These results suggest that the accumulation of irinotecan in HCC leads to the development of drug resistance.

Multi-centre phase II trial of Thalidomide in the treatment of unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumour, which overexpresses vascular endothelial growth factor. Thalidomide is an antiangiogenic agent with activity in refractory multiple myeloma. The purpose of this multi-centre phase II study was to evaluate the efficacy and toxicity of thalidomide in patients with advanced HCC. From February 2000 to November 2001, 37 patients with histologically proven, bi-dimensionally measurable advanced, unresectable HCC were enrolled. The starting dose of Thalidomide was 100 mg per day and escalated weekly by 100 mg to a maximum dose of 800 mg/day according to individual patient tolerance. Radiological tumour response and treatment related toxicities were prospectively assessed. Thirty-seven patients were evaluable for toxicity and 24 patients were evaluable for response. The median Thalidomide dose was 400 mg/day. There was no complete response (CR). One patient had a radiological partial response (PR) (3%; 95% confidence interval [95% CI], 0% to 8%) and six (16%) patients had stable disease for more than 6 months. Somnolence and fatigue were the most common side effects, occurring in 84% and 73% of patients respectively. Thalidomide monotherapy is tolerable and associated with modest antitumour activity in advanced HCC.

Complete tumor response following intratumoral 32P BioSilicon on human hepatocellular and pancreatic carcinoma xenografts in nude mice

PURPOSE

32P BioSilicon is a new, implantable, radiological medical device that comprises particles of highly pure silicon encapsulating 32phosphorus (32P) for the treatment of unresectable solid tumors. Prior to administration, the device particles are suspended in a formulant which provides an even suspension of the intended dose for implantation. The primary objective of this animal trial study was to investigate the effects of intratumoral injection of 32)P BioSilicon on human hepatocellular (HepG2) and pancreatic carcinoma (2119) xenografts implanted in nude mice (BALB/c). A secondary objective was the histopathologic examination of the tumor foci and surrounding tissue during the study.

METHODS

Cultured human carcinoma cells (HepG2 and 2119) were injected s.c. into the gluteal region of nude mice. When the implanted tumors were approximately 1 cm in diameter, 32P BioSilicon (0.5, 1.0, and 2.0 MBq) or formulant was injected into the tumors. Implanted tumor size was measured once a week for 10 weeks. At study termination, the tumor and surrounding normal tissue were collected and fixed in 10% formalin and processed for histopathologic analysis.

RESULTS

32P BioSilicon produced a reduction in HepG2 tumor volume when compared with formulant control, and complete response was observed among tumors in the 1.0 and 2.0 MBq treatment groups after week 8. There was also significant reduction in 2119 tumor volume in all treated groups, with the complete response rate of 67% in the 2.0 MBq group.

CONCLUSION

32P BioSilicon suppressed the growth of both human hepatocellular and pancreatic carcinoma xenografts implanted in nude mice and complete responses were also observed in tumors at higher radiation doses.

A critical evaluation of hepatic resection in cirrhosis: optimizing patient selection and outcomes

Hepatic resection has long been the mainstay of treatment of primary liver cancers, particularly hepatocellular carcinoma (HCC). Because of the high incidence of cirrhosis in patients with HCC, the use of resection was initially limited by the ability of the cirrhotic liver to sustain the surgical insult and the mass reduction. Today, hepatectomy in cirrhosis is undergoing a remarkable evolution. Although surgical and anesthetic improvements have increased the safety of this option, the rapid development of alternative therapies has decreased the need for it. Local excision for small HCC is likely to be replaced by image-guided, percutaneous ablative techniques. Furthermore, total replacement of a cirrhotic liver may be a more effective long-term cure than resection. Unquestionably, resection remains the optimal approach for patients with large tumors and healthy underlying liver function. The role of rapidly evolving new approaches will remain the subject of intensive inquiry in the years to come. In this report, we have attempted to clarify current practice with respect to the evaluation, selection, and technique of resection in cirrhosis, and identify areas of active inquiry.

MYC inactivation uncovers pluripotent differentiation and tumour dormancy in hepatocellular cancer

Hepatocellular carcinoma is generally refractory to clinical treatment. Here, we report that inactivation of the MYC oncogene is sufficient to induce sustained regression of invasive liver cancers. MYC inactivation resulted en masse in tumour cells differentiating into hepatocytes and biliary cells forming bile duct structures, and this was associated with rapid loss of expression of the tumour marker alpha-fetoprotein, the increase in expression of liver cell markers cytokeratin 8 and carcinoembryonic antigen, and in some cells the liver stem cell marker cytokeratin 19. Using in vivo bioluminescence imaging we found that many of these tumour cells remained dormant as long as MYC remain inactivated; however, MYC reactivation immediately restored their neoplastic features. Using array comparative genomic hybridization we confirmed that these dormant liver cells and the restored tumour retained the identical molecular signature and hence were clonally derived from the tumour cells. Our results show how oncogene inactivation may reverse tumorigenesis in the most clinically difficult cancers. Oncogene inactivation uncovers the pluripotent capacity of tumours to differentiate into normal cellular lineages and tissue structures, while retaining their latent potential to become cancerous, and hence existing in a state of tumour dormancy.

Down-regulation of growth arrest DNA damage-inducible gene 45beta expression is associated with human hepatocellular carcinoma

In this study, we describe the growth arrest DNA damage-inducible gene 45beta (GADD45beta), whose expression was significantly down-regulated in the hepatocellular carcinoma (HCC) microarray study and confirmed by Northern blot analysis. The results suggested that expression of GADD45beta was decreased in human liver cancer cell lines HepG2 and Hep3B, but not in normal human embryonic liver cell line CL-48 or normal liver tissue. Histochemistry study and real-time PCR further confirmed that GADD45beta staining in HCC was significantly decreased when compared to surrounding non-neoplastic liver tissue. In further studies of multiple human cancer tissues, GADD45beta strongly stained tissues such as colon cancer, breast cancer, prostate cancer, squamous cell cancer, lymphoma, and leiomyosarcoma, suggesting that the decreased expression of GADD45beta is specific to HCC. Eighty-five cases of primary HCC were further examined by immunohistochemistry and statistical analyses demonstrated that HCC scored lower than matched non-neoplastic liver tissues consistently and significantly. No staining occurred in 12.94% of HCC cases (score = 0, n = 11); 42.35% had weak staining (score = 1, n = 36); 27.06% had moderate staining (score = 2, n = 23); and 17.65% had staining as strong as normal tissue (score = 3, n = 15). Overall, surrounding non-neoplastic liver tissue was highly positive for GADD45beta compared to adjacent neoplastic liver tissues (P < 0.01). We further observed that down-regulation of GADD45beta expression was strongly correlated with differentiation (P < 0.01) and high nuclear grade (P < 0.01). Moreover, we found that expression of GADD45beta was inversely correlated to the presence of mutant p53 in HCC tissue (P < 0.05). Thus, the results of our study suggest that GADD45beta, which is down-regulated in most cases of HCC, remains an ideal candidate for development as a molecular marker in the diagnosis of HCC and as a potential therapeutic target.

Synergetic anticancer effect of combined quercetin and recombinant adenoviral vector expressing human wild-type p53, GM-CSF and B7-1 genes on hepatocellular carcinoma cells in vitro

AIM: This study investigated the anti-cancer effect of combined quercetin and a recombinant adenovirus vector expressing the human p53, GM-CSF and B7-1 genes (designated BB-102) on human hepatocellular carcinoma (HCC) cell lines in vitro.

METHODS: The sensitivity of HCC cells to anticancer agents was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The viability of cells infected with BB-102 was determined by trypan blue exclusion. The expression levels of human wild-type p53, GM-CSF and B7-1 genes were determined by Western blot, enzyme-linked immunosorbent assay (ELISA) and flow cytometric analysis, respectively. The apoptosis of BB-102-infected or quercetin-treated HCC cells was detected by terminal deoxynucleotidyl transferase (TdT) assay or DNA ladder electrophoresis.

RESULTS: Quercetin was found to suppress proliferation of human HCC cell lines BEL-7402, HuH-7 and HLE, with peak suppression at 50 μmol/L quercetin. BB-102 infection was also found to significantly suppress proliferation of HCC cell lines. The apoptosis of BB-102-infected HCC cells was greater in HLE and HuH-7 cells than in BEL-7402 cells. Quercetin did not affect the expression of the three exogenous genes in BB-102-infected HCC cells (P > 0.05), but it was found to further decrease proliferation and promote apoptosis of BB-102-infected HCC cells.

CONCLUSION: BB-102 and quercetin synergetically suppress HCC cell proliferation and induce HCC cell apoptosis, suggesting a possible use as a combined anti-cancer agent.