MDSC Proliferation in the 4T1 Breast Cancer Tumor Model
Mentor 1
Douglas Steeber
Location
Union 250
Start Date
28-4-2017 12:00 PM
Description
The immune system generates a T cell-mediated response to fight the progression of tumor growth by targeting abnormal self-cells. However, under conditions such as cancer, the production of suppressor cells in the bone marrow significantly increases and inhibits the anti-tumor response thus promoting tumor growth and metastasis. One specific type of suppressor cells are the myeloid-derived suppressor cells (MDSCs). These myeloid-lineage cells are released from the bone marrow in an immature state and are subsequently recruited to the tumor site. Previous studies in our lab using the murine 4T1 breast tumor model showed that MDSCs within the primary tumor were largely present in clusters located adjacent to regions of hypoxia where they increased in size with tumor growth. To determine the contribution of MDSC proliferation to cluster formation, bromodeoxyuridine (BrdU) labeling was performed followed by analysis with flow cytometry and immunohistochemistry. Specifically, 4T1 tumors were induced by injecting 4T1 cells into the mammary fat pad of female BALB/c mice and were allowed to grow for 4-5 weeks. Mice were pulsed with 100 micrograms/kilogram BrdU for 1 hour before sacrifice. The tumors were harvested and either frozen for cryosectioning or digested for single-cell preparations, and then labeled for MDSCs and BrdU for analysis by fluorescence microscopy and flow cytometry, respectively. Flow cytometry results showed that ~20% of the MDSCs were BrdU+ and thus indicated proliferation was occurring within the tumor. Immunohistochemistry studies are currently ongoing and will determine the location of the BrdU+ MDSCs in the tumor. Understanding the process of MDSC proliferation during tumor growth may provide novel information for the development of immunotherapeutic strategies targeting MDSCs to enhance the patient's anti-tumor immune response.
MDSC Proliferation in the 4T1 Breast Cancer Tumor Model
Union 250
The immune system generates a T cell-mediated response to fight the progression of tumor growth by targeting abnormal self-cells. However, under conditions such as cancer, the production of suppressor cells in the bone marrow significantly increases and inhibits the anti-tumor response thus promoting tumor growth and metastasis. One specific type of suppressor cells are the myeloid-derived suppressor cells (MDSCs). These myeloid-lineage cells are released from the bone marrow in an immature state and are subsequently recruited to the tumor site. Previous studies in our lab using the murine 4T1 breast tumor model showed that MDSCs within the primary tumor were largely present in clusters located adjacent to regions of hypoxia where they increased in size with tumor growth. To determine the contribution of MDSC proliferation to cluster formation, bromodeoxyuridine (BrdU) labeling was performed followed by analysis with flow cytometry and immunohistochemistry. Specifically, 4T1 tumors were induced by injecting 4T1 cells into the mammary fat pad of female BALB/c mice and were allowed to grow for 4-5 weeks. Mice were pulsed with 100 micrograms/kilogram BrdU for 1 hour before sacrifice. The tumors were harvested and either frozen for cryosectioning or digested for single-cell preparations, and then labeled for MDSCs and BrdU for analysis by fluorescence microscopy and flow cytometry, respectively. Flow cytometry results showed that ~20% of the MDSCs were BrdU+ and thus indicated proliferation was occurring within the tumor. Immunohistochemistry studies are currently ongoing and will determine the location of the BrdU+ MDSCs in the tumor. Understanding the process of MDSC proliferation during tumor growth may provide novel information for the development of immunotherapeutic strategies targeting MDSCs to enhance the patient's anti-tumor immune response.
