Figure 11.

Loss of Cav-1 in fibroblasts protects adjacent MCF7 cells against apoptosis. MCF7 cells were co-cultured for 72 hours with hTERT-fibroblasts carrying either a GFP (+) control shRNA (CTR) vector or a GFP (+) Cav-1 shRNA (KD) vector. Corresponding homotypic cultures were established in parallel. Then, the cells were subjected to annexin-V staining and analyzed by FACS. Thus, the GFP (+) and GFP (−) cells represent hTERT-fibroblasts and MCF7 cells, respectively. (A) MCF7 cell apoptotic rate: Cav-1 knockdown fibroblasts protect MCF7 cells against apoptosis. MCF7 cells co-cultured with CTR-fibroblasts show an ∼3-fold reduction in apoptosis, as compared to MCF7 cells cultured alone. However, co-cultures with KD fibroblasts provide MCF7 cells with a greater protection against apoptosis (8.5-fold decrease in apoptotic rate compared to MCF7 cell mono-cultures). The upper graph represents the percentage of annexin-V (+) cells. The lower graph represents the fold change versus MCF7 cells cultured in the absence of fibroblasts. *p ≤ 0.0002, **p ≤ 0.0000006 versus MCF7 cells cultured alone. *p ≤ 0.02 versus Cav-1 KD (Student's t-test). (B) Fibroblast apoptotic rate: Cav-1 knockdown protects fibroblasts against apoptosis. In homotypic cultures, KD fibroblasts are protected by 2.7-fold against apoptosis as compared to CTR fibroblasts. In addition, CTR fibroblasts co-cultured with MCF7 cells display a 2.4-fold increase in apoptosis, compared to CTR mono-cultures. Interestingly, co-cultured KD fibroblasts exhibit a 2-fold decrease in apoptosis compared to co-cultured CTR fibroblasts. These results suggest that a loss of Cav-1 protects fibroblasts in co-culture against apoptosis. *p = 0.03 versus the other three experimental conditions (Student's t-test).