Potent anti-tumor effects of a dual specific oncolytic adenovirus expressing apoptin in vitro and in vivo

Abstract

BackgroundOncolytic virotherapy is an attractive drug platform of cancer gene therapy, but efficacy and specificity are important prerequisites for success of such strategies. Previous studies determined that Apoptin is a p53 independent, bcl-2 insensitive apoptotic protein with the ability to specifically induce apoptosis in tumor cells. Here, we generated a conditional replication-competent adenovirus (CRCA), designated Ad-hTERT-E1a-Apoptin, and investigated the effectiveness of the CRCA a gene therapy agent for further clinical trials.ResultsThe observation that infection with Ad-hTERT-E1a-Apoptin significantly inhibited growth of the melanoma cells, protecting normal human epidermal melanocytes from growth inhibition confirmed cancer cell selective adenoviral replication, growth inhibition, and apoptosis induction of this therapeutic approach. The in vivo assays performed by using C57BL/6 mice containing established primary or metastatic tumors expanded the in vitro studies. When treated with Ad-hTERT-E1a-Apoptin, the subcutaneous primary tumor volume reduction was not only observed in intratumoral injection group but in systemic delivery mice. In the lung metastasis model, Ad-hTERT-E1a-Apoptin effectively suppressed pulmonary metastatic lesions. Furthermore, treatment of primary and metastatic models with Ad-hTERT-E1a-Apoptin increased mice survival.ConclusionsThese data further reinforce the previously research showing that an adenovirus expressing Apoptin is more effective and advocate the potential applications of Ad-hTERT-E1a-Apoptin in the treatment of neoplastic diseases in future clinical trials.

Parallel microfluidic chemosensitivity testing on individual slice cultures

“…GBM8 cells were labeled by lentiviral GFP expression to allow for the identification of the cells prior to xenograft generation. Xenografts were generated by injecting 200,000 viable glioma cells (trypan blue, a dead cell-selective dye, was used to determine the viability of cells) orthotopically into immunodeficient nude mice as described 26 , grown in vivo for ~4 weeks to allow tumor formation. The preparation and generation of the GBM xenograft slices followed the same protocol as mouse brain slices, except they were 400 μm thick.…”

Local non-viral gene delivery of apoptin delays the onset of paresis in an experimental model of intramedullary spinal cord tumor

“…40 Given the encouraging safety profile of apoptin and its broad spectrum of activity against tumor cells, current studies are focused on its efficient delivery. The delivery of apoptin via adenovirus, [41][42][43] baculovirus, 44 lentivirus-TAT 45 and HIV-TAT 46,47 has been reported. Although HIV-TAT delivery of apoptin is suboptimal for use, the other delivery methods show some initial promise; however, concerns remain.…”

Experimental research Therapeutic anti-tumor effect of exogenous apoptin driven by human survivin gene promoter in a lentiviral construct

“…Two critical issues have to be determined before the genetic manipulation on tumors: the gene(s) of interest and the promoter to drive the expression of the therapeutic gene(s). Apoptin has been previously applied in gene therapy under the control of highly active promoters, such as CMV promoter [7, 10, 19], which may cause some unwanted results when applied in a long-lasting expression construct. Although it is reported that apoptin is a safe protein with few side effects on normal cells [3, 20, 21], tumor-specific promoter may improve the safety of gene therapy since it preferentially drives therapeutic gene expression in the scenario of targeted tumor cells in contrast to normal cells.…”

“…Survivin, a member of the inhibitor of apoptosis protein (IAP) family, counteracts cell death and regulates mitotic progression, and is activated in most types, if not all, of tumor cells but not in normal cells [9, 10]. So, survivin promoter (pSur) has been tested as a transcriptional targeting strategy for tumor treatment [11–14], and showed a potent anti-tumor effect by driving the expression of tumor-specific short hairpin RNA (shRNA) [12], suicide genes [13], and sodium/iodide symporter [14].…”