Gene-viro-therapy targeting liver cancer by a dual-regulated oncolytic adenoviral vector harboring IL-24 and TRAIL

Cancer-targeting gene-viro-therapy is a promising cancer therapeutic strategy that strengthens the antitumor effect of oncolytic viruses by expressing an inserted foreign antitumor gene. To achieve liver cancer targeting and to improve the safety of the ZD55 vector (a widely-used E1B55KD gene-deleted oncolytic adenoviral vector (OV), we previously constructed), we designed a novel OV named Ad·AFP·D55 that selectively replicates in hepatocellular carcinoma (HCC) cells by replacing the E1A promoter with the liver-cancer specific α-Fetoprotein (AFP) promoter based on the ZD55 vector. We found that the oncolytic adenoviruses Ad·AFP·D55-IL-24 and Ad·AFP·D55-TRAIL express tumor-suppressor gene interleukin-24 (IL-24) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), respectively, significantly suppressed the HCC cell growth in vitro by inducing apoptosis by the caspase-8 and mitochondria-dependent caspase-9 signaling pathways. Furthermore, the combined treatment of Ad·AFP·D55-IL-24 and Ad·AFP·D55-TRAIL showed strong antitumor effects in vivo by significantly inhibiting the tumor growth in HCC HuH-7 cell xenograft mice, and markedly increasing animal survival rate. Therefore, this novel HCC cell-targeting OV carrying tumor-suppressor genes may provide a promising approach for liver cancer gene therapy.     

Transthyretin-driven oncolytic adenovirus suppresses tumor growth in orthotopic and ascites models of hepatocellular carcinoma

Strategies to increase antitumor efficacy of oncolytic adenoviruses are actively investigated. We have previously shown that E1B-55 kDa-deleted adenovirus, designated Ad5WS1, has therapeutic potential for treating hepatocellular carcinoma (HCC). To achieve HCC-restricted replication of oncolytic adenovirus, we generated Ad5WS2, an E1B-55 kDa-deleted adenovirus with its E1A gene driven by the liver-specific transthyretin promoter. Our results showed that Ad5WS2 could replicate within tumor cells where the transthyretin gene was expressed. Mouse transthyretin promoter was active in murine and human HCC cells, but relatively quiescent in cells of non-liver origin. Ad5WS2 caused severe cytolytic effect on HCC cells, but was much attenuated in non-HCC cells. Peritoneal administration of Ad5WS2 into mice bearing liver tumors grown in ascites resulted in enhanced survival. In an orthotopic HCC model, Ad5WS2, when systemically administered, exerted higher antitumor effects than Ad5WS1. Lack of viral replication in normal organs and minimal hepatic toxicity was noted after Ad5WS2 treatment. Furthermore, the antitumor effect of Ad5WS2 could be enhanced when combined with chemotherapeutic agent cisplatin in the ascites tumor model. These results suggest that E1B-55 kDa-deleted adenovirus driven by the transthyretin promoter may be a safer and more efficacious oncolytic agent for the treatment of primary and metastatic HCC. ( Cancer Sci 2009; 100: 537–545)     

A capsid-modified, conditionally replicating oncolytic adenovirus vector expressing TRAIL Leads to enhanced cancer cell killing in human glioblastoma models

Glioblastoma multiforme (GBM) is the most aggressive brain tumor, and patients rarely survive for more than 2 years. Gene therapy may offer new treatment options and improve the prognosis for patients with GBM. Adenovirus-mediated gene therapy strategies for brain tumors have been limited by inefficient gene transfer due to low expression of the adenovirus serotype 5 (Ad5) receptor. We have used an adenovirus vector that specifically replicates in tumor cells and uses an Ad5 capsid and the adenovirus serotype (Ad35) fiber for efficient infection of malignant tumor cells. This vector also expresses adenovirus E1A and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a tumor-specific manner. Here, we show that this oncolytic vector (Ad5/Ad35.IR-E1A/TRAIL) efficiently infects the GBM tumor cell lines SF767, T98G, and U-87 MG. Tumor cell killing was markedly enhanced with Ad5/Ad35.IR-E1A/TRAIL compared with wild-type Ad5 and Ad35 virus or Ad5/Ad35.IR-E1A- vectors without TRAIL expression in vitro. In vivo experiments using s.c. xenografted U-87 MG cells in NOD/SCID mice showed a significant growth delay of tumors after i.t. injection of Ad5/Ad35.IR-E1A/TRAIL, whereas adenovirus wild-type injections showed only marginal or no effect. Our findings indicate that the use of a capsid-modified adenoviral vector, in combination with TRAIL expression, is a promising novel approach for gene therapy of glioblastoma.     

Assessment of a combined, adenovirus-mediated oncolytic and immunostimulatory tumor therapy

In this study, we identified murine breast cancer cell lines that support DNA replication of E1-deleted adenovirus vectors and which can be killed by an oncolytic adenovirus expressing adenovirus E1A and tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) in a replication-dependent manner (Ad.IR-E1A/TRAIL). We showed that systemic or intratumoral (i.t.) injection of adenovirus vectors into mice increases plasma levels of proinflammatory cytokines and chemokines, including TNF-alpha, INF-gamma, and MCP-1, which are potent inducers of dendritic cell maturation. Furthermore, we showed that in vivo expression of Flt3L from an adenovirus vector increases the number of CD11b+ and CD11c+ cells (populations that include dendritic cells) in the blood circulation. Based on these findings, we tested whether Ad.IR-E1A/TRAIL induced killing of tumor cells in combination with dendritic cell mobilization by Ad.Flt3L or, for comparison, Ad.GM-CSF would have an additive antitumor effect. As a model, we used immunocompetent C3H mice with syngeneic s.c. tumors derived from C3L5 cells. We found that vaccination of mice with C3L5 cells that underwent viral oncolysis in combination with Flt3L or granulocyte-macrophage colony-stimulating factor (GM-CSF) expression induces a systemic antitumor immune response. I.t. injection of the oncolytic and Flt3L expressing vectors into established tumors delayed tumor growth but did not cause efficient tumor elimination. This study shows the effectiveness of a combined oncolytic/immunostimulatory tumor therapy approach.     

Ad.TERT-TRAIL对肿瘤细胞的杀伤作用及其机理

背景与目的：有学者用人端粒酶逆转录酶(TERT)启动子替换野生型腺病毒E1A自身的启动子,构建了一种肿瘤特异性增殖病毒,即溶瘤腺病毒Ad．TERT。细胞实验和动物实验表明,Ad．TERT有很好的抗癌作用。本研究目的是要在Ad．TERT中插入凋亡基因trail生成Ad．TERT—TRAIL,观察其是否具有更强的杀伤肿瘤细胞的功效并研究其机理。方法：通过腺病毒包装质粒pBHGE3与携带trail的小质粒pZhTERT—trail在HEK293细胞中同源重组构建Ad．TERT-TRAIL病毒．然后用PCR鉴定。并用Western blot检测E1A、trail基因的表达以进一步确证。用结晶紫染色法和MTT法检测Ad．TERT和Ad．TERT—TRAIL对肿瘤细胞和正常细胞杀伤作用的差异。用Western blot检测Caspase-3表达量以观察肿瘤细胞的凋亡情况,同时用流式细胞仪测定肿瘤细胞的凋亡率。结果：PCR扩增出来的条带为860bp．即为trail基因。Western blot结果显示．Ad．TERT—TRAIL中的E1A和trail只在肿瘤细胞中表达,说明Ad．TERT—TRAIL构建成功。结晶紫染色结果表明,Ad．TERT-TRAIL对肿瘤细胞的杀伤力比Ad．TERT高10～100倍．而对正常细胞的影响跟Ad．TERT一样小。100MOI(multiple of infection)Ad．TERT—TRAIL感染结肠癌细胞SW620 72h后．细胞存活率为4％：而感染了Ad．TERT的SW620细胞存活率却达56％。两种病毒对正常细胞NHLF的影响都比较弱,存活率在85％以上。随着作用时间的延长．感染了Ad．TERT—TRAIL和Ad．TERT的SW620细胞中Caspase-3的表达量都在升高,但前者的表达量明显大于后者．说明前者所引起的肿瘤细胞的凋亡程度比后者高。流式细胞仪检测结果显示,Ad．TERT—TRAIL引起SW620细胞的凋亡率是Ad．TFRT的4倍。结论：携带基因的溶瘤腺病毒Ad．TERT—TRAIL比单纯的溶瘤病毒Ad．TERT对肿瘤细胞的杀伤力更强,这种作用可能与trail基因能诱导Caspase-3表达量增加、大量肿瘤细胞凋亡有关。     

Targeting Gene‐ViroTherapy for prostate cancer by DD3‐driven oncolytic virus‐harboring interleukin‐24 gene

Prostate cancer (PCa) is the second leading cause of cancer‐related deaths in Western male population. Previous studies have demonstrated that differential display code 3 (DD3 or DD3^PCA3) is one of the most PCa‐specific genes; therefore, it has been used as a clinical diagnostic marker for PCa. In this study, we constructed an oncolytic adenovirus Ad.DD3‐E1A by using the minimal DD3 promoter to replace the native viral promoter of E1A gene. In addition, Ad.DD3‐E1A was armed with therapeutic gene IL‐24 to enhance its antitumor activity. The resulting adenovirus, Ad.DD3‐E1A‐IL‐24, demonstrated PCa specificity and excellent antitumor effect. Further analyses on its antitumor mechanism revealed that it has the capacity to induce apoptosis in PCa cells and inhibit angiogenesis. These results suggest that Ad.DD3‐E1A‐IL‐24 is a promising antitumor agent that may be able to be used in the future as a treatment for PCa.     

Replicating adenoviral vector-mediated transfer of a heat-inducible double suicide gene for gene therapy

Tumor cells that express a fusion gene of Escherichia coli cytosine deaminase (CD) and herpes simplex virus type 1 thymidine kinase (TK) sequences activate and are subsequently killed by the nontoxic prodrugs 5-fluorocytosine and ganciclovir. We have previously developed a recombinant adenovirus containing the CD-TK fusion gene controlled by the human inducible heat shock protein 70 promoter so that heat at 41 degrees C for 1 hour induces therapeutic gene expression. This adenovirus effectively transduces heat-inducible expression of the CD-TK gene into human prostate carcinoma cells. However, because a limited number of cells in a tumor can actually be infected, we created a replicating adenoviral vector to increase CD-TK gene expression. This vector is a replication-competent, E1B-attenuated adenoviral vector containing the hsp70 promoter-driven CD-TK gene (Ad.E1A(+)HS-CDTK). When human prostate adenocarcinoma DU-145 cells (mutant p53) were infected with the virus at a multiplicity of infection (MOI) of 1 or 10, the viral replication was detected within 2 days at both MOIs. Similar results were observed in human colorectal carcinoma CX-1 cells. When DU-145 cells were infected with the virus at an MOI of 10, incubated for 24 hours, heated at 41 degrees C for 4 hours, and then harvested 20 hours later, Western blot analysis demonstrated that this virus successfully produced viral E1A proteins and heat shock stimulated the CD-TK gene expression by 12.3-fold. In addition, Ad.E1A(+)HS-CDTK effectively suppressed cell proliferation by viral cytopathic effect). Unlike with a replication-incompetent virus (Ad.HS-CDTK), the cytopathic effect of the virus and cytotoxicity in the presence of the prodrugs were still observed even at low MOI (MOI=1.0).     

Adenoviral vector expressing CYLD augments antitumor activity of TRAIL by suppression of NF-kappaB survival signaling in hepatocellular carcinoma

CYLD is a tumor suppressor gene related to cylindroma and is negative regulator of NF-kappaB. However, antitumor effect of CYLD has not been reported. The activation of NF-kappaB induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) renders hepatocellular carcinoma (HCC) resistant to TRAIL-mediated cell apoptosis. Here we described that the adenoviral vector expressing CYLD (Ad/hTERT-CYLD) augmented the cytotoxicity of TRAIL in HCC cells by negatively regulating NF-kappaB activity since CYLD could reverse the ubiquitination of TNF receptor-associated factor 2 (TRAF2) and interact with the IkappaB kinasegamma (IKKgamma). The combined treatment of Ad/hTERT-CYLD and a conditionally replicating adenovirus carrying TRAIL gene (ZD55-TRAIL) induced rapid and potent apoptosis in HCC cells, characterized by activation of caspase-3, caspase-8, PARP and the reduction of X-linked inhibitor of apoptosis protein (XIAP). In animal study, the combined treatment could eradicate the BEL7404 xenograft tumors. In contrast, treatment with Ad/hTERT-CYLD or ZD55-TRAIL alone achieved less antitumor effect. In conclusion: CYLD inhibits TRAIL-mediated NF-kappaB activation and enhances the sensitivity of HCC cells to TRAIL-triggered apoptosis. The combined delivery of Ad/hTERT-CYLD and ZD55-TRAIL may be a new useful strategy for HCC or other tumor cells with enhanced NF-kappaB activity.     

The addition of adenovirus type 5 region E3 enables calydon virus 787 to eliminate distant prostate tumor xenografts.

CV787, a novel highly prostate-specific replication-competent adenovirus with improved efficacy, was constructed. CV787 contains the prostate-specific rat probasin promoter, driving the adenovirus type 5 (Ad5) E1A gene, and the human prostate-specific enhancer/promoter, driving the E1B gene. To improve efficacy, we constructed CV787 such that it also contains the entire Ad5 E3 region. CV787 replicates in prostate-specific antigen (PSA)+ cells as well as wild-type adenovirus, but in PSA- cells, CV787 replicates 10(4)-10(5) times less efficiently. CV787 destroys PSA+ prostate cancer cells 10,000 times more efficiently than PSA- cells. Incorporation of the Ad5 E3 region significantly improves the target cell killing ability or efficacy of CV787. In nu/nu mice carrying s.c. LNCaP xenografts, a single i.v. tail vein injection of CV787 eliminates 300-mm3 tumors within 4 weeks. CV787 could be a powerful therapeutic for human metastatic prostate cancer.     

Adenovirus E1A reverses the resistance of normal primary human lung fibroblast cells to TRAIL through DR5 upregulation and caspase 8-dependent pathway

Expression of the adenovirus serotype 5 (Ad5) E1A enhances tumor cells to apoptosis by TNF-alpha, Fas-ligand and TNF-related apoptosis-inducing ligand (TRAIL). In this study, we found that E1A expression reversed the resistance of normal primary human lung fibroblast cells (P-HLF) to TRAIL-induced apoptosis. Furthermore, TRAIL dramatically induced apoptosis of P-HLF cells that expressed E1A following either infection with Ad-E1A or transfection with pcDNA3-E1A. Further results demonstrated that E1A specifically upregulated DR5 levels but had nearly no effect on the levels of DR4. E1A dramatically upregulated the exogenous TRAIL, and then increased a substantial amount of TRAIL on the surface of P-HLF cells treated with the expression vectors, both Ad-TRAIL and pIRES-EGFP-TRAIL. The dominant negative FADD mutation (FADD-DN) results revealed that the apoptosis in Ad-E1A and Ad-TRAIL coinfected P-HLF cells was completely blocked following inhibition of the death receptors-associated apoptosis-inducing molecules FADD. Moreover, the caspase 8 inhibitor (Z-IETD-FMK) could efficiently block caspase 8 activation and resulted in inhibition of caspase 3 activation and cleavage. However, The caspase 9 specific inhibitor (Z-LEHD-FMK) could not counteract the synergistic effect of TRAIL-induced apoptosis in combination with E1A, and caspase 3 activation and cleavage were not inhibited by Z-LEHD-FMK. Thus, our results suggest that adenovirus E1A sensitizes P-HLF cells to TRAIL-induced apoptosis involving DR5 upregulation and the caspase 8-dependent pathway. These findings provide the first direct evidence for molecular mechanisms of adenovirus E1A gene products to sensitize normal cells to TRAIL-mediated apoptosis.     

Anticancer activity of oncolytic adenovirus vector armed with IFN-alpha and ADP is enhanced by pharmacologically controlled expression of TRAIL

We have previously described oncolytic adenovirus (Ad) vectors KD3 and KD3-interferon (IFN) that were rendered cancer-specific by mutations in the E1A region of Ad; these mutations abolish binding of E1A proteins to p300/CBP and pRB. The antitumor activity of the vectors was enhanced by overexpression of the Adenovirus Death Protein (ADP, E3-11.6K) and by replication-linked expression of IFN-alpha. We hypothesized that the anticancer efficacy of the KD3-IFN vector could be further improved by expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). E1-deleted Ad vectors were constructed carrying reporter genes for enhanced green fluorescent protein or secreted placental alkaline phosphatase (SEAP) and a therapeutic gene for TRAIL under control of the TetON system. Expression of the genes was increased in the presence of a helper virus and the inducer doxycycline such that up to 231-fold activation of expression for the TetON-SEAP vector was obtained. Coinfection with TetON-TRAIL augmented oncolytic activity of KD3 and KD3-IFN in vitro. Induction of TRAIL expression did not reduce the yield of progeny virus. Combination of TetON-TRAIL and KD3-IFN produced superior antitumor activity in vivo as compared with either vector alone demonstrating the efficacy of a four-pronged cancer gene therapy approach, which includes Ad oncolysis, ADP overexpression, IFN-alpha-mediated immunotherapy, and pharmacologically controlled TRAIL activity.