Figure 2.

TGF‐β, secreted by breast and prostate cancer cells, blocks the disruption of cancer cells via osteocyte conditioned media. Similarly, knockdown of osteocyte TGF‐β receptor I in co‐culture resulted in similar effects to normal osteocyte conditioned media, inhibiting proliferation and increasing migration of breast and prostate cancer cells, indicating TGF‐β plays a role in feedback loop. A) Fold‐increases in TGF‐β secretion by cancer cell lines compared to standard culture media, as measured by ELISA. Fold‐change in B) proliferation and migration of breast (MDA‐MD‐231 & MCF‐7) and prostate (PC‐3 & LNCaP) cancer cell lines, after 48 h in osteocyte CM, with or without TGF‐β pre‐treatment (n = 9). Data normalized to untreated control cancer cells. Quantification of C) proliferation and migration of breast and prostate cancer cell lines, after 48 h in co‐culture (Co‐C) with osteocytes in which TGF‐β receptor I has been knocked down with siRNA (TGFβR KD) (n = 9). Data normalized to co‐culture with non‐transfected osteocytes and shown alongside scrambled controls (SCRAM). Bar charts represent mean ± standard deviation. Statistically significant differences indicated by horizontal lines based on one‐way ANOVA with Bonferroni post‐hoc test (light gray p < 0.05, dark gray p < 0.01, black p < 0.001).