(A) Outgrowth of HMF fibroblasts co-cultured with MCF-7 breast cancer cells whose pro-cath- D secretion of which was inhibited by siRNA silencing.
HMF fibroblasts were embedded in Matrigel with or without a bottom layer of MCF-7 cancer cells (panel a). Phase contrast optical photomicrographs of HMF fibroblasts embedded alone (panel b, right) or in the presence of a bottom layer of MCF-7 cells (panel b, left and middle) after 3 days of co-culture are shown. High magnifications of the boxed regions are displayed below. Phase contrast optical photomicrographs of MCF-7 cells transfected with cath-D or luc siRNAs after 3 days of co-culture are presented (panel c). Expression and secretion of pro-cath-D were monitored in MCF-7 cell lysates (C) and media (S) before the beginning of the co-culture, and then in the media at day 1 to 3 of co-culture by western blot (panel d). Secretion of pro-cath-D was also monitored in media of HMF cells embedded alone at day 3 of co-culture (panel d). Expression of cath-D in a HMF lysate (C) is shown.
(B) Outgrowth of HMF fibroblasts co-cultured with 3Y1Ad12 cancer cells secreting no procath- D, pro-cath-D or D231N pro-cath-D.
HMF fibroblasts were embedded with or without a bottom layer of 3Y1Ad12 cancer cell lines secreting no pro-cath-D (control), human wild-type (pro-cath-D), or D231N pro-cath-D (D231N) as described in Fig. 1A (panel a). Phase contrast optical photomicrographs of HMF fibroblasts after 3 days of co-culture are shown (panel a). High magnifications of the boxed regions are displayed below. Phase contrast optical photomicrographs of 3Y1-Ad12 cancer cell lines after 3 days of co-culture are presented (panel b). Pro-cath-D secretion was analyzed after 3 days of co-culture by western blot (panel c). Arrows indicate fibroblasts. Bars (---, 50 μm). *, non-specific contaminant protein. K, molecular mass in kilodaltons.