CA on cell proliferation persists, even on removal of the drug. Induction of Apoptosis in Human Breast Cancer Cell Lines Correlates with an Elevation in Bax Levels We next determined whether ACCA decreases cell viability of breast cancer cells through the induction of apoptosis. Thus, cells were treated for 48h with 200 uM of ACCA and phosphatidylserine translocation was measured by flow cytometry and annexin V labeled with FITC. Annexin V, a Ca2+-dependent phosphatidylserine binding protein, detects phosphatidylserine translocation onto the outer plasma membrane leaflet. Propidium iodide staining was used in conjunction with Annexin V-FITC for the detection of necrotic cells. Annexin V-negative/PI-negative, Annexin V positive/PI-negative, Annexin V positive/PIpositive, AnnexinV-negative/PI-positive cells represent the viable cells, the cells in early apoptosis, late apoptosis, and necrosis, respectively. As shown in Fig. 4, ACCA induced early and late apoptosis in 85.8, 77.6 and 65.9% of the cell population of MCF-7, MDA/MB 231 and T47D respectively at dose of 200 mmol/L for 48 h. compared to untreated cells. We also found that ACCA induces necrosis in 21.6, 13, 31.8% of the cell population of MCF-7, MDA/MB 231 and T47D respectively, suggesting that ACCA might also cause significant cellular injury and increased apoptotic cell death. We next define potential target genes associated with apoptosis that might be regulated by ACCA, thereby resulting in apoptosis in breast cancer cells. Because of the importance of Bcl-2 family proteins in the regulation of apoptosis, we monitored the levels of expression of 345627-80-7 antiapoptotic proteins 10742299 and the proapoptotic proteins in breast cancer cells. As shown in Fig. 5, ACCA decreased Bcl-2 protein level whereas Bax protein expression were elevated in MCF-7, T47D and MDA- 231 breast cancer cells, respectively. In contrast, the levels of the various pro- and antiapoptotic proteins did not change significantly in 17636045 HBL-100 cells following treatment with. ACCA. These studies suggest that ACCA increases the ratio of of pro- to antiapoptotic proteins, thereby tipping the balance of cancer cells from survival to programmed cell death. ACCA Treatment Decreases Cell Motility, Invasion and in Vivo Tumor Growth of MDA-231 Human Breast Cancer Cells To investigate whether ACCA can affect important biological properties of breast cancer cells, we first used in vitro cell migration and invasion assays. As shown in Fig. 6A, the migratory and invasive ability of MDA-231 cells was significantly affected in a concentration-dependent manner by ACCA. At the highest concentration of 200 uM, ACCA causes an up to,90 and 85% reduction in cell migration and invasion, respectively, as compared to untreated cells. We also determine the effect of multiple i.p. injections of ACCA on growth of MDA-231 cells subcutaneously implanted in nude mice. The ACCA concentrations delivered as a treatment protocol in the present study are within the range used in previous animal studies. A shown in Fig. 6B, the average tumor volume in mice treated with ACCA was significantly lower compared to vehicle-treated control mice. At 32 days after tumor cell injection, MDA-231 cells gave rise to small tumors as compared to vehicle-treated control mice indicating that ACCA reduced tumour growth by,94%. Although, treatment of mice receiving MDA-231 cells with ACCA at 8 days resulted in a less dramatic decrease in tumor growth, the difference was still evident.