Figure 10.

Overexpression of PAI-1 or PAI-2 in stromal fibroblasts reduces tumor apoptosis. Tunnel assays were performed on MDA-MB-231 tumors grown in the presence of fibroblasts (control vs. those overexpressing PAI-1 or PAI-2) and the numbers of apoptotic cells were quantitated. (A) Representative images of tunnel assay staining are shown. Images were captured at an original magnification of 40x. Slides were counterstained with hematoxylin. (B) Quantification of apoptotic tumor cell number. Note that apoptosis in MDA-MB-231 was significantly reduced when grown in presence of PAI-1- or PAI-2-overexpresing fibroblasts as compared with control fibroblasts. Results are represented as the mean ± SEM. An asterisk indicates that p ≤ 0.05 and two asterisks indicate that p ≤ 0.001. Ctrl, fibroblasts containing empty vector alone; PAI-1, fibroblasts overexpressing PAI-1; PAI-2, fibroblasts overexpressing PAI-2; MDA, MDA-MB-231 (GFP⁺).