Date of Award

7-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Biological Sciences

Advisor

Yu, Xianzhong

Committee Member

Wagner , Thomas E

Committee Member

Wei , Yanzhang

Abstract

According to the different phenotypes and distinct patterns of gene expression, macrophages can be subdivided into two types: M1 and M2. The M1 macrophages, which are activated through the classical pathway, have a proinflammatory characteristic, providing an in-front defense line against different kinds of pathogens as well as malignant cells. On the other hand, the M2 macrophages are immunosuppressive and instead can promote tumor growth and dissemination. The solid tumor tissues are often infiltrated with a large number of macrophages, the so-called tumor-associated macrophages (TAMs). TAMs, which are polarized into M2 phenotype under the tumor microenvironment, promote tumor progression by favoring angiogenesis, extracellular matrix (ECM) remodeling, and tuning down of adaptive immunity. Although the molecular mechanisms underlying the process of macrophage polarization is not fully understood, defective activation of NF-ĸB signaling pathway has been frequently observed in TAMs. Pharmacological skewing of TAM polarization from an M2-like phenotype to a full M1 phenotype has been shown to sustain antitumor immunity. In the present study, a novel macrophage-targeted, particulate-mediated gene delivery system was designed aiming to modulate the activation status of the targeted macrophage cells for cancer therapy. Using zymosan particles conjugated with recombinant adenoviruses encoding different interferon regulatory factor (IRF) family genes, specifically IRF1, IRF3, and IRF7, the current system, taking advantage of the characteristic of phagocytosis of macrophages as well as the capability of adenovirus to escape from the phagosomes, achieved virtually 100% transduction efficiency in RAW-Blue macrophage cell line. Through reporter assay, cytokine antibody array, and the measurement of NO production, our results showed an increased NF-ĸB activity in the cells treated by the adenovirus-zymosan conjugates. In addition, cytokine antibody array analysis also revealed increased expressions of many pro-inflammatory cytokines down-stream of the NF-ĸB or IRF signaling pathway in treated cells. This increased expression of pro-inflammatory cytokines probably reflects an added effect from three different sources: the effect elicited by the binding of zymosan to the TLR2; the effect from the cells sensing viral dsDNA through TLR9-dependent and/or -independent pathways; and the effects directly from the expression of the transfected IRF genes. Further works are needed to study the effects of the current system in primary mouse macrophages, especially to test whether the transfected macrophages have elevated activities against tumor cells.

Included in

Oncology Commons

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