Fig. 2

Osteocyte-driven tumor-suppressive capabilities in vitro, ex vivo, and in vivo. CN control (plain medium), and CM conditioned medium. The single and double asterisks indicate P < 0.05 and P < 0.01, respectively. a Reduction in the migration (as assessed by a wound-healing assay) of 4T1.2 mammary tumor cells induced by A5 CM. Scale bar: 200 μm. b Significant reduction in the invasion of primary human breast cancer cells from 2 sources after 48 h of treatment with A5 osteocyte-derived CM. Scale bar: 200 μm. c Significant shrinkage of ex vivo breast cancer tissue fragments by A5 osteocyte-derived CM. The green image at 48 h is overlaid on the red image at 0 h. Scale bar: 200 μm. d Significant reduction in the number of green fluorescence-labeled EO771 mammary tumor cells (yellow arrows) in the lungs of C57BL/6 mice after coinjection with A5 osteocyte-derived CM in the extravasation assay. e Schematic diagram of a vinculin FRET biosensor: the tension-sensitive sensor consists of the head and tail domains of vinculin with an elastic FRET module. In response to a strong (or weak) force, the sensor exhibits a long (or short) donor lifetime. f A5 CM-driven significant reduction in the fluorescence lifetime of a vinculin biosensor in EO771 and MDA-MB-231 cells. The observed reduction in the fluorescence lifetime indicates A5 CM’s inhibitory effects on molecular force and cell migration. Scale bar: 20 μm