Media from APP over-expressing CHO cells suppress MDA-MB231-L and B16F-L cell proliferation. MDA-MB231-L and B16F-L cells (500 cells/well), APP over-expressing CHO cells (7W cells) and CHO cells (1000 cells/well) were seeded in 96 well plates. After 36 hr, media of MDA-MB231-L and B16F-L cells were replaced with the media from 7W or CHO cells. Proliferation of the MDA-MB231-L and B16F-L cells was measured by BLI assay at 24 hr post medium replacement. (A) A representative image from MDA-MB231-L cells cultured with conditioning media (CM) from CHO cells (CHO-CM) or from 7W cells (7W-CM) for 24 hr. 7W-CM and control CHO-CM were applied to 6 wells of adenocarcinoma MDA-MB231-L cells, respectively (top panel CHO-CM, lower panel 7W-CM). (B) Mean values from three independent experiments were obtained, and media from 7W cells showed inhibition of MDA-MB231-L proliferation, compared to media from CHO cells. The standard error of means (SEM) was illustrated (n = 12), and the asterisk indicates a statistically significant difference between two groups (P < 0.05, one-way ANOVA followed by Fisher's post-hoc test). (C) Persistent inhibitory effect of CM from 7W cells on MDA-MB231-L cell proliferation. The proliferation of the MDA-MB231-L cells was measured by BLI assay at 24, 48 and 72 hr post medium replacement. The photon counts at 24 hr before medium replacement (-24 hr) were used as the baseline for the calculation of relative cell numbers. All values indicate means ± SEM (n = 6), and significant difference between CM from 7W and control CHO cells is indicated by * P < 0.05. (D) Inhibitory effect of media from APP over-expressing CHO cells on melanoma (B16F-L) cell proliferation. B16F-L cells were quantified by BLI assay at 24, 48 and 72 hr after incubation with CM from 7W or CHO cells. All values represent means ± SEM (n = 6), and CM from 7W cells showed significant difference in it ability to inhibit B16F-L cell proliferation compared to CM from control CHO cells, as indicated by * P < 0.05.