Despite successes in animals, cytokine gene expression selectively in human tumors is difficult to achieve due to lack of efficient delivery methods. We previously demonstrated that adoptively transferred, IL-2 activated natural killer (A-NK) cells are very effective in trafficking to, infiltrating and, subsequently, reducing B16 lung tumors in tumor-bearing animals. We therefore speculated that the tumor-seeking A-NK cells could be used for the delivery of cytokines selectively to the tumor microenvironment. However, tumor infiltration by A-NK cells depends on high and often toxic doses of IL-2 to support the transferred A-NK cells survival and anti-tumor functions. To address this problem, we hypothesized that A-NK cells transduced to express pro-NK cell cytokines would become less dependent on high and potentially toxic amounts of IL-2. Assessments of transduction efficiency in vitro demonstrated that adenoviral transduction consistently resulted in high (>60%) transduction rates and substantial expression of transgenes such as GFP, luciferase, and mIL-12 for at least 4 days. In vivo experiments illustrated that mIL-12 transduced A-NK cells localized and survived significantly better than mock transduced cells within lung metastases than in the surrounding normal lung tissue when supported with low, non-toxic doses of IL-2. The intratumoral survival of non-transduced bystander A-NK cells also increased when they were co-injected with IL-12 gene-transduced A-NK cells. The enhanced survival of exogenously delivered, IL-12 gene-transduced A-NK cells resulted in greater anti-tumor responsiveness. This led to a 7-10 day increase in median survival time compared to tumor-bearing mice receiving mock-transduced A-NK cells. These data show that the presence of IL-12 around tumor-infiltrating A-NK cells enhances their anti-tumor activity while reducing their requirement for systemically administered IL-2. This A-NK cell delivered IL-12 has lead to an enhanced host anti-tumor reactivity, which appeared to be mediated through cytokine involvement, namely IFNγ, rather than T, B, and NK cellular activity. Thus, adoptive transfer of A-NK cells represents an efficient method for targeting products of genes to tumor sites and eliciting anti-tumor responses.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07162008-204724 |
| Date | 23 July 2008 |
| Creators | Goding, Stephen R. L. |
| Contributors | Per Basse, Elieser Gorelik, Pawel Kalinski, Andrea Gambotto, Nikola Vujanovic |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-07162008-204724/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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