Abstract 2093: Sunitinib suppresses the proliferation, migration, apoptosis resistance, tumor angiogenesis and growth in MDA-MB-468 cell cultures and xenografts .

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC We previously reported the anti-tumor efficacy of sunitinib (VEGF receptor tyrosine kinase inhibitor) in murine ER-positive breast cancer xenograft model, in which sunitinib suppressed both autocrine and paracrine effects in breast cancer progression. The investigations of sunitinib on triple-negative breast cancer are very limited. The clinical utility of sunitinib is less understood in the setting of breast cancer. The present study determines: 1) whether VEGF is highly expressed in MDA-MB-468 cells, compared to MCF-7 and MDA-MB-231 cells; 2) whether sunitinib inhibits the proliferation, migration, apoptosis resistance of cultured MDA-MB-468 cells; 3) whether oral sunitinib treatment suppresses tumor angiogenesis and growth in MDA-MB-468 xenografts; and 4) whether sunitinib changes % of breast cancer stem cells in the xenografts. MDA-MB-231, MDA-MB-468, MCF-7 cells were cultured using RPMI 1640 media with 10% FBS. VEGF protein levels were detected using ELISA (R&D Systams). MDA-MB-468 cells were exposed to sunitinib for 18 hours for measuring proliferation (3H-thymidine incorporation), migration (BD BioCoat Matrigel Invasion Chamber), and apoptosis (Millipore ApopTag). 10ˆ6 MDA-MB-468 cells inoculated into the left fourth mammary gland fat pad in athymic nude-foxn1 mice. When the tumor volume reached 100 mmˆ3, sunitinib was given by gavage at 80 mg/kg/2 days for 4 weeks. Tumor angiogenesis was determined by CD31 immunohistochemistry. Breast cancer stem cells were determined by flow cytometry analysis using CD44+/CD24- or low. VEGF protein levels in MDA-MB-468 cells were 10257±292 pg/ml that are 3-folds higher than those (3428±74 pg/ml) in MDA-MB-231 cells and 31-folds higher than those (335±4 pg/ml) in MCF-7 cells (P<0.01, n=6). 1, 5 and 10 μmol/L of sunitinib caused 24, 41 and 59% reduction in the proliferation of MDA-MB-468 cells, respectively, compared to the control (P<0.01, n=6). Sunitinib at 1 μmol/L significantly inhibited the migration of MDA-MB-468 cells by 45% compared to the control (P<0.01, n=6). Sunitinib (5 μmol/L) increased 31% apoptosis of MDA-MB-468 cells (P<0.01). Oral sunitinib treatment significantly inhibited tumor angiogenesis and tumor growth, and slightly increased % of breast cancer stem cells in the xenografts. These findings suggest that VEGF is highly expressed in triple negative breast cancer (TNBC) cells especially in MDA-MB-468 cells. VEGF receptor tyrosine kinase inhibitor (sunitinib) can inhibit autocrine effects (proliferation, migration, and apoptosis resistance) and paracrine effects (tumor angiogenesis) in triple negative breast cancer progression. However, the possibility should be considered of sunitinib increasing breast cancer stem cells. Sunitinib or other anti-VEGF agents in TNBC therapy may have to be combined with cancer stem cell-targeting drugs. Citation Format: Edmund Chinchar, Kristina L. Makey, John Gibson, Lucio Miele, Jian-Wei Gu. Sunitinib suppresses the proliferation, migration, apoptosis resistance, tumor angiogenesis and growth in MDA-MB-468 cell cultures and xenografts . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2093. doi:10.1158/1538-7445.AM2013-2093