Sulfatase 2 decreases breast cancer cell invasion and proliferation. A) MDA-MB-231 (MB-231) and MDA-MB-435 S (MB-435) cell invasion was assayed with treatment of recombinant hSulf2 protein compared to buffer treatment (0). Stably hSulf2 transfected cells (S2) were also compared to control vector transfected cells for invasive ability * = p < 0.002; ** = p < 0.001; *** = p < 0.04. B) Invasion assays were performed with MDA-MB-231 cells in the presence of the EGFR kinase inhibitor PD153035 or rhSulf2. C) For the proliferation assay, cells were plated and collected over 4 days to test mitochondrial reductase metabolic activity using the MTT assay. Decreased MTT conversion in hSulf2 transfected cells corresponded to non-proliferating cells during this period. D) Recombinant human Sulfatase 2 protein (rhSulf2) was added to MDA-MB-231 cells at 250 nM, and cells assayed over 3 days using the MTT assay. E) Cell viability is expressed as percent of live cells and corresponds to data represented in panel C. F) Corresponding cell viability data for panel D; n.s. = not significant.