Tomoya Tsuchiyama

Prolonged, NK Cell-Mediated Antitumor Effects of Suicide Gene Therapy Combined with Monocyte Chemoattractant Protein-1 against Hepatocellular Carcinoma

Tumor recurrence rates remain high after curative treatments for hepatocellular carcinoma (HCC). Immunomodulatory agents, including chemokines, are believed to enhance the antitumor effects of tumor cell apoptosis induced by suicide gene therapy. We therefore evaluated the immunomodulatory effects of a bicistronic recombinant adenovirus vector (rAd) expressing both HSV thymidine kinase and MCP-1 on HCC cells. Using an athymic nude mouse model (BALB/c-nu/nu), primary s.c. tumors (HuH7; human HCC cells) were completely eradicated by rAd followed by treatment with ganciclovir. The same animals were subsequently rechallenged with HCC cells, tumor development was monitored, and the recruitment or activation of NK cells was analyzed immunohistochemically or by measuring IFN-γ mRNA expression. Tumor growth was markedly suppressed as compared with that in mice treated with a rAd expressing the HSV thymidine kinase gene alone (p < 0.001). Suppression of tumor growth was associated with the elevation of serum IL-12 and IL-18. During suppression, NK cells were recruited exclusively, and Th1 cytokine gene expression was enhanced in tumor tissues. The antitumor activity, however, was abolished either when the NK cells were inactivated with anti-asialo GM1 Ab or when anti-IL-12 and anti-IL-18 Abs were administered. These results indicate that suicide gene therapy, together with delivery of MCP-1, eradicates HCC cells and exerts prolonged NK cell-mediated antitumor effects in a model of HCC, suggesting a plausible strategy to prevent tumor recurrence.

Monocyte chemoattractant protein-1 gene delivery enhances antitumor effects of herpes simplex virus thymidine kinase/ganciclovir system in a model of colon cancer

Suicide gene therapy using the herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system is a well-characterized tool for cancer gene therapy; however, it does not yet exhibit sufficient efficacy to cure patients of malignancies. We have reported that adenovirally delivered monocyte chemoattractant protein (MCP)-1 augmented the antitumor effects of the HSV-tk/GCV system in an athymic nude mouse model. The current study, which uses an immunocompetent mouse model of colon cancer, was designed to evaluate the antitumor effects of MCP-1 gene delivery in conjunction with this suicide gene therapy system. Subcutaneous tumor foci were directly transduced with both recombinant adenoviruses (rAds) expressing an HSV-tk gene and either of the MCP-1, CD80 and LacZ genes, followed by GCV administration. The growth of tumors was markedly suppressed by codelivery of HSV-tk and MCP-1 genes, which was exclusively associated with the recruitment of monocytes/macrophages, T helper 1 (Th1) cytokine gene expression and cytotoxic activity of the splenocytes. Furthermore, the antitumor effects were more efficient than that obtained by the combination of HSV-tk and CD80 genes. These results suggest an immunomodulatory effect of MCP-1 in the context of suicide gene therapy of colon cancer via orchestration of innate and acquired immune responses.

Enhanced antitumor effects of a bicistronic adenovirus vector expressing both herpes simplex virus thymidine kinase and monocyte chemoattractant protein-1 against hepatocellular carcinoma

The efficacy of the suicide gene therapy using the herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system for the treatment of cancer is limited because of the insufficient gene transfer and the low killing activity. To enhance the antitumor activity, we determined whether recombinant adenovirus vector (rAd)s expressing both HSV-tk and monocyte chemoattractant protein-1 (MCP-1) genes could potentiate the destruction of hepatocellular carcinoma (HCC). The rAd Ad-tk-MCP1 harboring HSV-tk and MCP-1 genes in sequence under the universal CAG promoter was constructed with a bicistronic unit including the encephalomyocarditis virus-internal ribosomal entry site. The levels of HSV-tk expression and GCV-sensitive tumoricidal activity of Ad-tk-MCP1 were comparable to those of rAd expressing HSV-tk alone. The growth of subcutaneous tumors in athymic nude mice was markedly suppressed when tumors were treated with Ad-tk-MCP1 as opposed to another bicistronic vector Ad-MCP1-tk, rAd expressing either HSV-tk or MCP-1, or both of these vectors. The antitumor effects of Ad-tkMCP1 may be dependent on the activation of macrophages, since the recruitment of macrophages was observed tumor necrosis factor-α production was enhanced in the tumor tissue. Furthermore, the enhanced antitumor effect was abolished by inactivating macrophages with carrageenan treatment. These results demonstrated that a bicistronic rAd harboring both suicide and chemokine genes in sequence exerted the enhanced, macrophage-dependent, antitumor effects in a model of HCC and support the use of this strategy for the treatment of HCC.

Optimal amount of monocyte chemoattractant protein-1 enhances antitumor effects of suicide gene therapy against hepatocellular carcinoma by M1 macrophage activation.

Suicide gene therapy combined with chemokines provides significant antitumor efficacy. Coexpression of suicide gene and monocyte chemoattractant protein‐1 (MCP‐1) increases antitumor effects in murine models of hepatocellular carcinoma (HCC) and colon cancer. However, it is unclear whether the doses administered achieved the maximum antitumor effects. We evaluated antitumor effects of various amounts of recombinant adenovirus vector (rAd) expressing MCP‐1 in the presence of a suicide gene in a murine model of HCC. HCC cells were transplanted subcutaneously into BALB/c nude mice, and transduced with a fixed amount of Ad‐tk harboring the suicide gene, HSV‐tk, and various doses of Ad‐MCP1 harboring MCP‐1 (ratios of 1:1, 0.1:1, and 0.01:1 relative to Ad‐tk). Growth of primary tumors was suppressed when treated with Ad‐tk plus Ad‐MCP1 (1:1 and 1:0.1) as compared with Ad‐tk alone. The antitumor effects against tumor rechallenge tended to be high in the Ad‐tk plus Ad‐MCP1 group (1:0.1). The effects were dependent on production of Th1 type‐cytokines. Delivery of an optimal amount of rAd expressing MCP‐1 enhanced the antitumor effects of suicide gene therapy against HCC by M1 macrophage activation, suggesting that this is a plausible form of cancer gene therapy to prevent HCC progression and recurrence. (Cancer Sci 2008; 99: 2075–2082)

Prevention of intrahepatic metastasis of liver cancer by suicide gene therapy and chemokine ligand 2/monocyte chemoattractant protein-1 delivery in mice

The prognosis of patients with hepatocellular carcinoma (HCC) remains poor, largely as a result of intrahepatic metastasis. Using a mouse model of intrahepatic metastasis, we investigated whether chemokine ligand 2/monocyte chemoattractant protein‐1 (CCL2/MCP‐1) could potentiate the antitumor effects of the herpes simplex virus thymidine kinase/ganciclovir (HSV‐tk/GCV) system.

Diagnostic utility of aberrant methylation of tissue factor pathway inhibitor 2 in pure pancreatic juice for pancreatic carcinoma

The tissue factor pathway inhibitor 2 (TFPI‐2) is a Kunitz‐type serine proteinase inhibitor. Recently, the aberrant methylation of TFPI‐2 was detected frequently in pancreatic carcinoma (PCa) tissues but not in normal pancreatic tissues. We analyzed the aberrant methylation of TFPI‐2 in the pure pancreatic juice (PPJ) aspirated endoscopically from patients with various pancreatic diseases. Using the highly sensitive methylation‐specific polymerase chain reaction (MSP) and quantitative MSP (Q‐MSP) assay, we investigated the aberrant methylation of TFPI‐2 in nine human PCa cell lines and in the PPJ from patients with PCa, intraductal papillary mucinous neoplasms (IPMN) and chronic pancreatitis (CP). The incidence of aberrant TFPI‐2 methylation was seven (77.8%) of nine PCa cell lines by Q‐MSP. In cell lines, the expression of TFPI‐2 mRNA by quantitative reverse transcription–polymerase chain reaction showed an inverse correlation to the aberrant methylation of TFPI‐2. The incidence of aberrant TFPI‐2 methylation in the PPJ was 21 (58.3%) of 36 PCa patients, three (17.6%) of 17 IPMN and one (4.8%) of 21 CP by MSP assay. Using a suitable cut‐off value of 2.5 according to the receiver operating characteristic curve, the incidence of aberrant TFPI‐2 methylation in the PPJ by real‐time MSP was 18 (62.1%) of 29 PCa patients, one (5.1%) of 17 IPMN and three (14.3%) of 21 CP, respectively. The incidence of quantitative TFPI‐2 hypermethylation in the PPJ with PCa was significantly higher than that with IPMN (P < 0.001) or CP (P < 0.001). Moreover, the aberrant methylation rate of TFPI‐2 in the PPJ was 100%, as observed (6/6) in the PCa patients with liver metastasis, and 86.7% (26/30) in stages IVa + IVb of PCa by Q‐MSP assay. These results suggest that promoter methylation of TFPI‐2 in the PPJ may be a useful marker in the diagnosis and progression of PCa using an endoscopically feasible approach. (Cancer Sci 2006; 97: 1267–1273)

Membrane-bound form of monocyte chemoattractant protein-1 enhances antitumor effects of suicide gene therapy in a model of hepatocellular carcinoma

Suicide gene therapy using the herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system combined with monocyte chemoattractant protein-1 (MCP-1) provides significant antitumor efficacy. The current study was designed to evaluate the antitumor immunity of a newly developed membrane-bound form of MCP-1 (mMCP-1) in an immunocompetent mouse model of hepatocellular carcinoma (HCC). A recombinant adenovirus vector (rAd) harboring the human MCP-1 gene and the membrane-spanning domain of the CX3CL1 gene was used. Large amounts of MCP-1 protein were expressed and accumulated on the tumor cell surface. The growth of subcutaneous tumors was markedly suppressed when tumors were treated with mMCP-1, as compared with soluble MCP-1, in combination with the HSV-tk/GCV system (P<0.01). The numbers of Mac-1-, CD4- and CD8a-positive cells were significantly higher in tumor tissues (P<0.05), and tumor necrosis factor (TNF) mRNA expression levels with mMCP-1 were almost five-fold higher than those with soluble MCP-1. These results indicate that the delivery of the mMCP-1 gene greatly enhanced antitumor effects following the apoptotic stimuli by promoting the recruitment and activation of macrophages and T lymphocytes, suggesting a novel strategy of immune-based gene therapy in the treatment of patients with HCC.

Tiny staining spots in liver cirrhosis associated with HCV infection observed by computed tomographic hepatic arteriography: follow-up study

Background: It is important to distinguish small lesions with increased arterial perfusion observed by computed tomographic arteriography (CT-A) from hepatocellular carcinoma (HCC). However, the clinical characteristics and prognosis of such lesions have not been clarified. Methods: We retrospectively examined 200 patients with cirrhosis related to hepatitis C virus (HCV) infection who had undergone both CT-A and CT arterioportography between 1995 and 1998, and found 80 tiny staining spots (TSS)s, with a diameter of 5–10 mm, by CT-A (35 patients). The mean TSS observation period was 29.0 months. If the major axis was larger than 10 mm and showed a 1.5-fold or more increase, the lesion was regarded as tumor growth (TG). The TSS lesions were divided into two groups according to whether the patient had or did not have HCC. The prognosis of TSS was classified into three groups; HCC-suspected group, nontumor group, and unclassified group, in which TG was negative although transcatheter arterial embolization (TAE) had been performed. Results: Of the 40 TSSs in 14 patients without HCC, 2 (5%) were suspected as HCC. Of the 40 TSSs in 21 patients with HCC, 13 (32.5%) were suspected as HCC. There were no significant differences in the size, position, and morphology of TSSs among the three prognostic groups. Of the 7 TSSs with a high signal intensity on T2-weighted magnetic resonance (MR) images, 5 were in the HCC-suspected group. Conclusions: We recommend early treatment of TSSs accompanying HCC or showing features of malignancy at the imaging workup.

Improvement of Hepatic Protoporphyrin Accumulation After Antibiotic Treatment

Erythropoietic protoporphyria (EPP) is an autosomal dominantly inherited disorder that is related to a decreased activity of the enzyme ferrochelatase, catalyzing the formation of heme from protoporphyrin IX and iron (1). EPP is characterized clinically by skin photosensitivity, which usually appears during early childhood, and biochemically by elevated red cell protoporphyrin levels. Acute hepatic failure is the most serious complication of EPP and has been estimated to occur in 1‐10% of patients (1, 2). Clinically, jaundice and abdominal pain are the most common symptoms due to accumulation of protoporphyrin in the liver. The liver disease is also known to progress relentlessly towards terminal hepatic failure once it becomes symptomatic and then liver transplantation is usually required to save the life of the patient (3). In this article, we present a rare case with recognized improvement of hepatic protoporphyrin accumulation after antibiotic treatment. CASE REPORTS A man, born in 1959, had a history of erythropoietic protoporphyria (EPP) since the age of 18. The diagnosis was made on the basis of severe skin photosensitivity and elevated protoporphyrin (PP) levels. His father and uncles were also affected by the disease. Until 1994, he was in good health except for skin photosensitivity.

Advanced hepatocellular carcinoma treated effectively with irinotecan via hepatic arterial infusion followed by proton beam therapy

We report a 48-year-old man with hepatocellular carcinoma (HCC) treated with hepatic arterial infusion (HAI) chemotherapy followed by proton beam therapy. The HCC lesion in this patient was 88 mm in diameter, with portal vein tumor thrombosis in the right lobe of the liver. He was first treated with 5-fluorouracil, cisplatin, and isovorin, administered by HAI, combined with interferon-α, and he was subsequently treated with epirubicin and mitomycin-C administered by HAI. However, no definite efficacy of either of these treatments was observed. Then, after 3 weeks’ continuous administration of irinotecan by HAI, the tumor size decreased to 68 mm in diameter. However, 3 months after reduction of the tumor, the tumor had become enlarged to 100 mm in diameter and intrahepatic metastases were prominent. Angiographic findings indicated that the HCC was fed not only from the right hepatic artery but also from the left gastric and right and left subphrenic arteries. After rearrangement of the arteries, and 3 months’ continuous HAI chemotherapy with irinotecan, plus hyperthermia, the tumor size had decreased to 50 mm in diameter. The reduction rate of the main tumor according to the Response Evaluation Criteria in Solid Tumors was 43%; therefore, the efficacy of this treatment was judged as a partial response. Two months after reduction of the tumor, the patient’s serum alpha-fetoprotein (AFP) level was elevated, and so docetaxel was administered by HAI instead of irinotecan. The liver tumors showed gradual enlargement during the administration of docetaxel, although the AFP level was suppressed. Proton beam therapy was instituted and the liver tumors showed necrosis after this therapy. The patient died of hepatic failure and distant metastases 6 years after the onset of HCC. As far as we know, this is the first case report of HCC treated effectively with irinotecan administered by HAI followed by proton beam therapy in which tumor suppression and the long-term survival of the patient were observed.