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Oncolytic adenoviral vectors which employ the survivin promoter induce glioma oncolysis via a process of beclin-dependent autophagy.

ABSTRACT: Survivin has gained attention as a tumor-specific marker which is upregulated in a variety of neoplasms. Although the survivin protein is implicated in anti-apoptotic tumor pathways, little is known about the function of the survivin promoter. In this study, we constructed a conditionally replicative adenoviral vector (CRAd) that utilizes the survivin promoter and examined the mechanism of CRAd induced cell death in malignant glioma. Our results indicate that CRAd vectors which utilize the survivin promoter effectively replicate in glioma cells and exhibit a high oncolytic effect. The survivin-mediated CRAd appeared to induce apoptosis as measured by Annexin/7-AAD. Caspase-3 and BAX mRNAs were upregulated based on microarray data, however, Western blot analysis of infected cells showed no evidence of elevated caspase-3, BAX, or p53 protein expression. Of note, at each time point infected glioma cells showed no evidence of activated BAD or AKT. The inhibition of AKT signaling led us to examine autophagy in infected cells. Electron micrographs of virally infected glioma cells suggested auto-phagosomal-mediated cell death and selective blocking of beclin with siRNA prevented autophagy. These results indicate that the survivin promoter enhances viral replication and induces autophagy of infected glioma cells via a beclin-dependent mechanism.

SUBMITTER: Ulasov IV

PROVIDER: S-EPMC2790828 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

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Oncolytic adenoviral vectors which employ the survivin promoter induce glioma oncolysis via a process of beclin-dependent autophagy.

Ulasov Ilya V IV Tyler Mathew A MA Zhu Zeng B ZB Han Yu Y He Tong-Chuan TC Lesniak Maciej S MS

International journal of oncology 20090301 3

Survivin has gained attention as a tumor-specific marker which is upregulated in a variety of neoplasms. Although the survivin protein is implicated in anti-apoptotic tumor pathways, little is known about the function of the survivin promoter. In this study, we constructed a conditionally replicative adenoviral vector (CRAd) that utilizes the survivin promoter and examined the mechanism of CRAd induced cell death in malignant glioma. Our results indicate that CRAd vectors which utilize the survi ...[more]

PMID: 19212678

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Project description:Gene therapy has become an important strategy for treatment of malignancies, but problems remains concerning the low gene transferring efficiency, poor transgene expression and limited targeting specific tumors, which have greatly hampered the clinical application of tumor gene therapy. Gallbladder cancer is characterized by rapid progress, poor prognosis, and aberrantly high expression of Survivin. In the present study, we used a human tumor-specific Survivin promoter-regulated oncolytic adenovirus vector carrying P53 gene, whose anti-cancer effect has been widely confirmed, to construct a wide spectrum, specific, safe, effective gene-viral therapy system, AdSurp-P53. Examining expression of enhanced green fluorecent protein (EGFP), E1A and the target gene P53 in the oncolytic adenovirus system validated that Survivin promoter-regulated oncolytic adenovirus had high proliferation activity and high P53 expression in Survivin-positive gallbladder cancer cells. Our in vitro cytotoxicity experiment demonstrated that AdSurp-P53 possessed a stronger cytotoxic effect against gallbladder cancer cells and hepatic cancer cells. The survival rate of EH-GB1 cells was lower than 40% after infection of AdSurp-P53 at multiplicity of infection (MOI) = 1 pfu/cell, while the rate was higher than 90% after infection of Ad-P53 at the same MOI, demonstrating that AdSurp-P53 has a potent cytotoxicity against EH-GB1 cells. The tumor growth was greatly inhibited in nude mice bearing EH-GB1 xenografts when the total dose of AdSurp-P53 was 1 × 10(9) pfu, and terminal dUTP nick end-labeling (TUNEL) revealed that the apoptotic rate of cancer cells was (33.4 ± 8.4)%. This oncolytic adenovirus system overcomes the long-standing shortcomings of gene therapy: poor transgene expression and targeting of only specific tumors, with its therapeutic effect better than the traditional Ad-P53 therapy regimen already on market; our system might be used for patients with advanced gallbladder cancer and other cancers, who are not sensitive to chemotherapy, radiotherapy, or who lost their chance for surgical treatment.

Dataset Information

Oncolytic adenoviral vectors which employ the survivin promoter induce glioma oncolysis via a process of beclin-dependent autophagy.

Publications

Oncolytic adenoviral vectors which employ the survivin promoter induce glioma oncolysis via a process of beclin-dependent autophagy.

Similar Datasets

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