It has been shown that tumors have developed numerous ways to escape tumor specific immune responses. These mechanisms will ultimately not only enhance tumor growth, but also impair the effect of immune based therapies in cancer. Myeloid derived suppressor cells represent a recently identified cell population, which has been shown to impair tumor specific immune responses both in mice and human. MDSC can be divided in two subtypes (namely monocytic and granulocytic MDSC. We have been able to examine and define the regulation and function of murine MDSC by IFN-gamma.IFN-gamma induced STAT1 phosphorylation in both MDSC subsets, which led to NOS2 expression in CD11b+Gr-1dull/int monocytic MDSC and enhanced suppression of T cell proliferation. In sharp contrast, the suppressor function of CD11b+Gr-1high granulocytic MDSC was enhanced in the absence of IFN-gamma using IFN-gR-/- MDSC or IFN-gamma-/- effector cells, which led to upregulation of Bcl2a1 and improved survival of the granulocytic subpopulation during MDSC-T cell interaction. Likewise Bcl2a1 overexpression in CD11b+Gr-1high granulocytic MDSC supported their suppressor activity. Thus, depending on the local IFN-gamma concentration, STAT1 regulates the function of MDSC subsets antithetically so that these two cell populations can substitute each other and suppress antigen-specific T cell immunity.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
National Cancer Institute Division of Basic Sciences
Zip Code
Ma, Chi; Kesarwala, Aparna H; Eggert, Tobias et al. (2016) NAFLD causes selective CD4(+) T lymphocyte loss and promotes hepatocarcinogenesis. Nature 531:253-7
Ji, Juling; Eggert, Tobias; Budhu, Anuradha et al. (2015) Hepatic stellate cell and monocyte interaction contributes to poor prognosis in hepatocellular carcinoma. Hepatology 62:481-95
Gamrekelashvili, Jaba; Greten, Tim F; Korangy, Firouzeh (2015) Immunogenicity of necrotic cell death. Cell Mol Life Sci 72:273-83
Kapanadze, Tamar; Medina-Echeverz, José; Gamrekelashvili, Jaba et al. (2015) Tumor-induced CD11b(+) Gr-1(+) myeloid-derived suppressor cells exacerbate immune-mediated hepatitis in mice in a CD40-dependent manner. Eur J Immunol 45:1148-58
Medina-Echeverz, José; Eggert, Tobias; Han, Miaojun et al. (2015) Hepatic myeloid-derived suppressor cells in cancer. Cancer Immunol Immunother 64:931-40
Medina-Echeverz, José; Ma, Chi; Duffy, Austin G et al. (2015) Systemic Agonistic Anti-CD40 Treatment of Tumor-Bearing Mice Modulates Hepatic Myeloid-Suppressive Cells and Causes Immune-Mediated Liver Damage. Cancer Immunol Res 3:557-66
Medina-Echeverz, José; Haile, Lydia A; Zhao, Fei et al. (2014) IFN-γ regulates survival and function of tumor-induced CD11b+ Gr-1high myeloid derived suppressor cells by modulating the anti-apoptotic molecule Bcl2a1. Eur J Immunol 44:2457-67
Eggert, Tobias; Medina-Echeverz, José; Kapanadze, Tamar et al. (2014) Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage. PLoS One 9:e112717
Kapanadze, Tamar; Gamrekelashvili, Jaba; Ma, Chi et al. (2013) Regulation of accumulation and function of myeloid derived suppressor cells in different murine models of hepatocellular carcinoma. J Hepatol 59:1007-13
Ma, Chi; Kapanadze, Tamar; Gamrekelashvili, Jaba et al. (2012) Anti-Gr-1 antibody depletion fails to eliminate hepatic myeloid-derived suppressor cells in tumor-bearing mice. J Leukoc Biol 92:1199-206

Showing the most recent 10 out of 11 publications