Estudo da modulação das células mielóides supressoras no adenocarcinoma metastático após terapia antiangiogênica ; Study of modulation of the myeloidderived suppressor cells metastatic adenocarcinoma after antiangiogenic therapy

Renal cell carcinoma (RCC), the third leading cause of death in genitourinary cancers. RCCs are highly vascularized and resistant to radiotherapy and chemotherapy. Antiangiogenic drugs are promising and widely used in clinical, on the other hand, mechanism of evasive resistance has been seen to treatment with anti-VEGF antibody. Recent reports suggest that treatment resistance of patients with cancer is related to the presence of myeloid-derived suppressor cells. Endostatin (ES) is a fragment of collagen XVIII that mediates antiangiogenic activity, however, its mechanisms of action are unclear. In this study, we tracked Gr-1+ cells in different organs, evaluated the role of CD11b+Gr-1+ cells and their subsets during tumoral progression and examined the therapeutic potential of ES in modulating CD11b+Gr-1+ cells and their subsets as well as their immunosuppressive activities in lung metastasis. Healthy Balb/c mice were used to detect Gr-1+ cells. CCRm-bearing mice were nephrectomized on day 7 and collected metastatic lung, spleen and bone marrow after 3, 7 and 10 days. Quantification of CD11b+Gr-1+ cells and their monocytic and granulocytic subsets was performed by flow cytometry and microscopic analysis were viewed in HE staining. CCRm-bearing mice were treated with NIH/3T3-LendSN-clone 5 or with NIH/3T3-LXSN cells as a control. ES and G-CSF levels were measured by ELISA and Milliplex, respectively. Quantification of CD11b+Gr-1+ cells and their subsets was performed by flow cytometry. Gr-1+ cells magnetically separated were evaluated in vitro the nitrite levels in supernatant and arginase activity in cells by colorimetric assays. ROS production was measured in CD11b+Gr-1+ cells using the DCFDA marker by flow cytometry. Our data showed the presence of CD11b+Gr-1+ cells in the bone marrow as well as in the kidney, lung and spleen, confirming the monocytic and granulocytic morphologies In metastatic progression, saw the expansion of CD11b+Gr-1+ cells and, preferably, the granulocytic subtype in the bone marrow. Our ...