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Intraarterial delivery of adenovirus vectors and liposome-DNA complexes to experimental brain neoplasms
N G Rainov1, K Ikeda, N H Qureshi
1Neuroscience Center, Massachusetts General Hospital, and Neurology Department, Harvard Medical School, Boston 02129, USA.
Abstract:
This study investigated the intraarterial delivery of genetically engineered replication-deficient adenovirus vectors (AVs) and cationic liposome-plasmid DNA complexes (lipoDNA) to experimental brain tumors. Adenovirus or lipoDNA was injected into the internal carotid artery (ICA) of F344 rats harboring intracerebral 9L gliosarcomas, using bradykinin (BK) to selectively permeabilize the blood-tumor barrier (BTB). Brain and internal organs of the animals were collected 48 hr after vector injection and stained for expression of the marker gene product, beta-galactosidase (beta-Gal). Intracarotid delivery of AV to 9L rat gliosarcoma without BTB disruption resulted in transgene expression in 3-10% of tumor cells distributed throughout the tumor. Virus-mediated expression of beta-gal gene products in this tumor model was particularly high in small foci (< or = 0.5 mm), which had invaded the normal brain tissue surrounding the main tumor mass. In these foci more than 50% of tumor cells were transduced. BK infusion increased the amount of transgene-expressing cells in larger tumor foci to 15-30%. In the brain parenchyma only a few endothelial cells expressed beta-gal owing to AV-mediated gene transfer. Intracarotid delivery of lipoDNA bearing a cytoplasmic expression cassette rendered more than 30% of the tumor cells positive for the marker gene without BTB disruption. The pattern of distribution was in general homogeneous throughout the tumor. BK infusion was able to increase further the number of transduced tumor cells to more than 50%. Although lipoDNA-mediated gene transfer showed increased efficacy as compared with AV-mediated gene transfer, it had less specificity since a larger number of endothelial and glial cells also expressed the transgene. AV and lipoDNA injections, in the absence and presence of BK, also resulted in transduction of peripheral organs. AV showed its known predilection for liver and lung. In the case of lipoDNA, parenchymal organs such as liver, lung, testes, lymphatic nodes, and especially spleen, were transduced. These findings indicate that intracarotid application of AV and lipoDNA vectors can effectively transduce tumor cells in the brain, and that BTB modulation by BK infusion can further increase the number of transgene-expressing tumor cells.
Insights
Intraarterial delivery of adenovirus vectors (AVs) and liposome-plasmid DNA (lipoDNA) effectively transduced brain tumor cells in rats. Bradykinin (BK) enhanced gene transfer efficiency, but lipoDNA showed lower specificity compared to AVs.
Area of Science:
- Gene Therapy
- Neuro-oncology
- Biotechnology
Background:
- Effective delivery of gene therapy vectors to brain tumors remains a significant challenge.
- The blood-tumor barrier (BTB) limits the penetration of systemically administered therapeutic agents into brain malignancies.
- Intraarterial delivery offers a potential route to bypass systemic circulation and target brain tumors directly.
Purpose of the Study:
- To investigate the efficacy and specificity of intraarterial delivery of adenovirus vectors (AVs) and cationic liposome-plasmid DNA complexes (lipoDNA) for brain tumor gene transfer.
- To evaluate the impact of bradykinin (BK)-mediated blood-tumor barrier (BTB) permeabilization on gene transfer efficiency.
- To compare the transduction patterns and potential off-target effects of AVs and lipoDNA in a rat brain tumor model.
Main Methods:
- Adenovirus vectors (AVs) and liposome-plasmid DNA (lipoDNA) were administered via the internal carotid artery (ICA) in F344 rats with intracerebral 9L gliosarcomas.
- Bradykinin (BK) was infused to selectively permeabilize the blood-tumor barrier (BTB).
- Beta-galactosidase (beta-Gal) expression was analyzed in brain and peripheral organs 48 hours post-injection to assess gene transfer.
Main Results:
- Intracarotid AV delivery resulted in transgene expression in 3-10% of tumor cells, with higher transduction (>50%) in small invasive foci.
- LipoDNA delivery achieved higher transduction efficiency (>30%) homogeneously throughout the tumor, further enhanced by BK (>50%).
- AVs showed higher specificity with minimal non-tumor cell transduction, while lipoDNA transduced more endothelial and glial cells; both vectors transduced peripheral organs.
Conclusions:
- Intracarotid administration of AVs and lipoDNA can effectively deliver genes to brain tumor cells in vivo.
- Bradykinin-mediated BTB modulation significantly enhances the number of transgene-expressing tumor cells for both vector types.
- LipoDNA demonstrates higher efficacy but lower specificity compared to AVs, highlighting the need for vector optimization for targeted brain tumor gene therapy.