Date of Award


Degree Type




First Advisor

Zhou, Aimin

Subject Headings

Ribonucleases, Macrophages, Endocytosis, Cancer -- Immunological aspects, Biochemistry, RNase L, Macrophages, Endocytosis, Phagocytosis, Cytokines, Cancer Immunology, Tumor-associated macrophages


RNase L is one of the key enzymes in the 2-5A system of interferon (IFN) action against viral infection and cellular proliferation. Tissue distribution analysis has revealed that RNase L is highly expressed in the spleen, thymus, lung, testis, intestine and most of immune cells such as T, B cells and macrophages. However, the physiological role of RNase L in the immune system is largely unknown. My thesis thus focused on studying the possible physiological role of RNase L in macrophages. By using bone marrow-derived macrophages (BMMs) from RNase L+/+and -/- mice, we demonstrated that RNase L is involved in macrophage functions and migration ability. RNase L deficient BMMs showed a significant reduction of endocytic activity to FITC-Dextran 40,000 compared to wild type cells. In addition, lack of RNase L remarkably decreased the migration of BMMs under both normal condition and condition induced by M-CSF, GM-CSF or CCL2. To determine the role of RNase L in tumor growth, P53-/- RL-/- cancer cells were subcutaneously implanted on the back of RNase L null and wild type mice with C57BL/6 background, respectively. Surprisingly, the average tumor weight from RNase L+/+ mice was 3-fold heavier than that from RNase L-/- mice indicating that presence of RNase L was overtly favorite for tumor growth. Immunofluorescence staining revealed that the numbers of infiltrated macrophages were markedly higher in the tumor tissues from the wild type mice. Depletion of macrophages clearly inhibited tumor growth on RNase L+/+ mice, suggesting that RNase L may promote tumor growth through regulating the function of tumor-associated macrophages (TAMs). Taken together, our findings implicate that RNase L may play a dual role in innate immunity and tumor promotion. Additionally, in a collaborated project, we successfully identified and investigated the molecular targets of an anti-cancer drug candidate. In this study, we performed protein pull down assays to purify the anti-cancer targets of the compound. Via proteomic approaches, the maj

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