FIG. 5.

Mechanically loading tumor cells affected osteopontin gene expression and protein deposition in BM-MSCs. (A) Loaded and Nonloaded (NL) tumor-conditioned media were generated from MDA-MB231 tumor cells (1.5 × 10⁶ per scaffold) cultured in HA-containing scaffolds that underwent 1 h of cyclic compression (1 Hz, 10% peak strain) and then processed as previously described. Control, nonloaded media was generated similarly. (B) Mechanical loading of tumor cells did not alter downstream growth patterns in BM-MSCs. (C) Similarly, no differences in ALP enzyme activity were detected. (D) Quantitative real-time polymerase chain reaction (qRT-PCR) revealed that mechanical loading increased OPN expression in BM-MSCs, and this effect was more pronounced when BM-MSCs were cultured in conditioned media from loaded tumor cells (Loaded tumor factors). (E) Immunohistochemistry suggested that mechanical loading also stimulated OPN protein deposition by BM-MSCs within scaffolds. Furthermore, BM-MSCs cultured with conditioned media from mechanically loaded versus nonloaded tumor cells resulted in more uniform protein deposition within the scaffolds. Scale bars = 100 μm. Same letters (a or b) indicate similar mean values, and groupings with different letters indicate that the difference is significant by post hoc comparison of means with Bonferroni correction (p < 0.05). Color images available online at www.liebertpub.com/tea