Tumor associated macrophages (TAMs) play an important role in establishing a pro-tumor environment in many tumor types. Produce low levels of inflammatory cytokines which creates pro-tumorigenic smoldering inflammation and also TAMs break down the surrounding extracellular matrix, secrete growth factors, and inhibit the adaptive immune response. TAMs are an attractive therapeutic target in cancer treatment, and strategically ablating these cells has been shown to remove their trophic effects. A more elegant solution would be to target these pro-tumor macrophages with a therapeutic agent that can alter their behavior to a strongly immunogenic phenotype capable of stimulating tumor immunity. The NF-κB pathways control macrophage phenotype and the inflammatory response. By selectively manipulating NF-κB in TAMs with siRNA, it should be possible to eradicate the TAM phenotype and recapitulate the normal immune response. I have developed a strategy to activate a classical immunogenic phenotype in TAMs. This strategy would stimulate tumor immunity by specifically activating the classical NF-κB pathway by knocking down the inhibitor of the pathway (IκBα).
Using mannosylated endosomal escape nanoparticles MnNP, I have transfected macrophages with siRNA targeting key NF-κB proteins. In vitro experiments show that MnNP rapidly and strongly transfect a small population of cells, as opposed to hydroxyl capped nanoparticles (OHNP) and commercial agents, which transfect many cells to a lesser degree and with less specificity. Analysis of IκBα knockdown macrophages shows a decrease in immunosuppressive cytokines, and an increase in a potent CD8+ T-cell recruiting cytokine, indicating a shift from a TAM-like phenotype, to an immunocompetent phenotype. In in vivo mouse models of human cancer, MnNP delivered nucleotides are taken up by mammary tumor TAMs to a greater extent than phagocytized, free siRNA and are protected within the core of the particle. Similarly, OHNP are not taken up by TAMs in solid ovarian tumors, while MnNP are able to evade non-specific uptake by cells in the ascites fluid and are taken up by tumor TAMs. In an intratracheal delivery model, MnNP have enhanced delivery to lung metastasis TAMs while OHNP are taken up nonspecifically by phagocytic granulocytes and monocytes.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-11232014-110428 |
| Date | 25 November 2014 |
| Creators | Ortega, Ryan Adam |
| Contributors | Todd D. Giorgio, Fiona E. Yull, Craig L. Duvall, Barbara Fingleton, Frederick R. Haselton |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-11232014-110428/ |
| 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 Vanderbilt University 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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