Telomerase-specific oncolytic adenovirus expressing TRAIL suppresses peritoneal dissemination of gastric cancer.

Peritoneal dissemination is the most common condition of metastasis in gastric cancer. The survival duration of a patient with advanced stage gastric cancer, may be improved by gene therapy. In this study, we used an oncolytic adenovirus vector (Ad/TRAIL-E1) that expresses both the TRAIL and E1A genes under the control of a tumor-specific promoter. We evaluated the anti-tumor effect of Ad/TRAIL-E1 on gastric cancer cells in vitro, as well as in vivo in a xenograft peritoneal carcinomatosis mouse model. Our data showed that Ad/TRAIL-E1 induced TRAIL-mediated apoptosis in gastric cancer cell lines, but not in the normal cell lines. In addition, Ad/TRAIL-E1 significantly inhibited peritoneal metastasis and prolonged the survival of mice without treatment-related toxicity. Therefore, tumor-specific TRAIL expression from an oncolytic adenovirus vector may provide a novel therapeutic approach for the treatment of advance stage gastric cancer with peritoneal dissemination.

The anti-tumor activity of E1A and its implications in cancer therapy.

The adenovirus type 5 E1A protein (E1A) plays a critical role in anti-cancer gene therapy and has been tested in clinical trials. The expression of E1A significantly reduces tumorigenesis, promotes cell death, and inhibits cancer cell mobility. Chemosensitization is one of the anti-tumor effects of E1A, increasing in vitro and in vivo sensitization of anti-cancer drugs, including cisplatin, gemcitabine, etoposide, doxorubicin, paclitaxel, and tumor necrosis factor-related apoptosis-inducing ligand and histone deacetylase inhibitors in different types of cancer cells. E1A also demonstrates anti-metastasis activity through various molecular mechanisms such as the repression of protease expression, suppression of HER2/neu and downregulation of microRNA (miR-520h). Moreover, E1A has been reported to reprogram transcription in tumor cells and stabilize tumor suppressors such as PP2A/C, p21 and p53. Because E1A plays a potentially significant role in anti-tumor therapy, there exists an urgent need to study the anti-cancer activities of E1A. This paper presents a review of our current understanding of the tumor-suppressive functions and molecular regulation of E1A, as well as the potential clinical applications of E1A.

Tat-PTD-modified oncolytic adenovirus driven by the SCG3 promoter and ASH1 enhancer for neuroblastoma therapy.

Secretogranin III (SGC3) belongs to the granin family and is highly expressed in endocrine and neural tissues. The human SCG3 promoter has not yet been characterized. We identified that a 0.5-kb DNA fragment upstream of the SCG3 gene can selectively drive transgene expression in neuroblastoma cell lines. The strength of transgene expression was further increased, with specificity maintained, by addition of the human achaete-scute complex homolog 1 (ASH1) enhancer. We developed an oncolytic serotype 5-based adenovirus, in which the SCG3 promoter and ASH1 enhancer drive E1A gene expression. The virus was further modified with a cell-penetrating peptide (Tat-PTD) in the viral capsid, which we have previously shown results in increased adenovirus transduction efficiency of many neuroblastoma cell lines. The virus, Ad5PTD(ASH1-SCG3-E1A), shows selective and efficient killing of neuroblastoma cell lines in vitro, including cisplatin-, etoposide-, and doxorubicin-insensitive neuroblastoma cells. Furthermore, it delays tumor growth and thereby prolonged survival for nude mice harboring subcutaneous human neuroblastoma xenograft. In conclusion, we report a novel oncolytic adenovirus with potential use for neuroblastoma therapy.

Conditionally replicating adenovirus therapy utilizing bone sialoprotein promoter (Ad-BSP-E1a) in an in vivo study of treating androgen-independent intraosseous prostate cancer.

BACKGROUND: Adenoviral based gene therapy has been used in clinical trials in control of advanced prostate cancer. In this study, a promising conditionally replicating adenovirus (CRAd) driven by a tissue specific bone sialoprotein promoter in controlling prostate cancer both in vitro and in vivo is demonstrated. METHODS: C4-2B, an androgen-independent prostate cancer cell line, was treated with PBS, Ad-BSP-TK, or the Ad-BSP-E1a in vitro, and in subcutaneous and intraosseous xenographs. Cell proliferation, PSA level in condition medium, tumor volume, and/or serum PSA were followed. RESULTS: The growth of C4-2B and the PSA production was dramatically suppressed by Ad-BSP-E1a at very low dosage (0.3 MOI) compared with PBS and Ad-BSP-TK treatment in vitro. In the subcutaneous model, the tumor volume was significantly lower statistically in the Ad-BSP-E1a treated group than the Ad-BSP-TK control group (P = 0.02). In the intraosseous model, the mice treated in the Ad-BSP-E1a treatment group demonstrated a significant lower PSA compared to that in the control group (P < 0.01) at week 8 and week 16 post-treatment. CONCLUSIONS: The CRAd Ad-BSP-E1a revealed potential in treating prostate cancer in this model system. Using viral or none-viral mediated gene therapy to treat prostate carcinoma continues to be a potential avenue to treat afflicted men with prostate cancer.

Phase I trial of intratumoral liposome E1A gene therapy in patients with recurrent breast and head and neck cancer.

PURPOSE: We conducted a Phase 1 study to determine the maximal tolerated dose and maximum biologically active dose of the E1A gene delivered by intratumoral injection as a lipid complex with 3 beta[N-(n',n'-dimethylaminoethane)-carbamoyl] cholesterol/dioleoylphosphatidyl-ethanolamine (tgDCC-E1A). The E1A adenovirus gene functions as a tumor inhibitor gene by repressing oncogene transcription; modulating gene expression, resulting in cellular differentiation; and inducing apoptosis of cancer cells. E1A also sensitizes cancer cells to chemotherapeutic drugs such as etoposide, cisplatin, and taxol. EXPERIMENTAL DESIGN: Nine patients with recurrent and unresectable breast cancer and nine patients with head and neck cancer were enrolled. One tumor nodule in each patient was injected with tgDCC-E1A. Safety, tumor response, E1A gene transfer, and down-regulation of HER-2/neu were evaluated. RESULTS: No dose-limiting toxicity was observed in the four dose groups (15, 30, 60, and 120 microg DNA/cm of tumor). All patients tolerated the injections, although several experienced pain and bleeding at the injection site. A maximally tolerated dose was not reached in this study. E1A gene transfer was demonstrated in 14 of 15 tumor samples tested, and down-regulation of HER-2/neu was demonstrated in two of the five patients who overexpressed HER-2/neu at baseline. HER-2/neu could not be assessed in other posttreatment tumor samples because of extensive necrosis. In one breast cancer patient, no pathological evidence of tumor was found on biopsy of the treated tumor site at week 12. In 16 patients evaluable for tumor response, 2 had minor responses, 8 had stable disease, and 6 had progressive disease. CONCLUSIONS: Gene therapy with an E1A gene:lipid complex appears to be safe and warrants further testing.

Tumor suppression activity of adenovirus E1a protein: anoikis and the epithelial phenotype.

Adenovirus E1a proteins reverse-transform diverse human tumor cells in culture. This has stimulated interest in the arenas of clinical and basic cancer research. Clinically, cancer gene therapy trials on E1a are in progress, and drug discovery strategies based on E1a are being considered. Biologically, the effect of E1a is unique in that it overrides most or all oncogenic signaling pathways to yield nontumorigenic cells. Apparently, this is a consequence of the ability of E1a to reprogram transcription in tumor cells so as to produce an epithelial phenotype that is refractory to oncogenic growth stimulation. The molecular basis for this effect is emerging.

Evaluation of E1-mutant adenoviruses as conditionally replicating agents for cancer therapy.

The oncolytic effect of adenoviruses may provide an efficient means to destroy tumor tissue if viruses could be developed with sufficient selectivity and efficacy. In this report we have characterized several adenoviruses, each with different mutations in the E1 region, for selective cytopathic effect in tumor cells in vitro and for their ability to inhibit tumor growth in vivo. Of the E1 mutants tested, we have identified one, E1Adl01/07, which preferentially induces cytopathic effects in a range of tumor cells versus primary cells. In addition, E1Adl01/07 significantly inhibited tumor growth and increased survival of mice in several models of human cancer. These results suggest that E1Adl01/07 might serve as an effective cancer therapeutic, combining both selectivity and efficacy.

[Down regulation of HER2/neu expression by adenovirus E1A and its anti-tumor activity].

OBJECTIVE: To study the growth inhibitory and chemo-sensitizing effects of adenovirus E1A gene on HER2/neu-overexpressing tumor cell lines. METHODS: E1A was transfected in vitro and in vivo by adenovirus vector into HER2/neu overexpressing human mammary cancer cell lines MDA-MB-453 and SKBR3 and their growth was monitored. The chemo-sensitizing effect was examined by MTT assay. RESULTS: E1A greatly inhibited growth of HER2/neu-overexpressing tumor and prolonged the survival time of tumor-bearing mice. Western blot and immunohistochemical analysis both showed suppression of p185 protein expression in E1A-transfected HER2/neu overexpressing cancer cell lines. E1A could sensitize HER2/neu-overexpressing human breast cancer cells to Taxotere by repressing HER2/neu expression. CONCLUSION: Adenovirus E1A inhibits tumor growth and sensitizes tumor cells to chemotherapeutic agent via down regulation of HER2/neu expression.

[Effect of adenovirus type 5 E1A gene on proliferation and metastasis of human lung adenocarcinoma cells].

OBJECTIVE: To investigate the effects of E1A gene on proliferation and metastasis of human lung adenocarcinoma cells. METHODS: A mammalian E1A-expressing recombinant constructed in our laboratory, named pcDNA3-E1A, was introduced into human lung adenocarcinoma cell line(Anip 973) by lipofectamine. The cells resistant to G418 were selected. The characteristics of the E1A-expressing Anip 973(Anip 973-E1A) cells were studied in vitro and in vivo, including cell growth rate and doubling-time, colony-forming efficiency on soft agarose, tumorigenicity and metastasis. RESULTS: The growth rate of E1A-Anip 973 cells was diminished and their colony-forming efficiency was inhibited significantly. The tumorigenicity in nude mice of the E1A-expressing Anip 973 was markedly suppressed. CONCLUSION: E1A suppresses the malignant phenotype of human lung adenocarcinoma cell line. This study provides experimental data for gene therapy of lung cancer with E1A.