APP over-expressing human neuroblastoma SH-SY5Y cells (SKAPP cells) had the similar inhibitory effects on the tumor cell proliferation. MDA-MB231-L cells, B16F-L cells (500 cells/well) and SKAPP, SKNSH cells (1000 cells/well) were seeded in separate 96 well plates. The number of MDA-MB231-L cells (A) and B16F-L cells (B) was measured by BLI assay at 24, 48 and 72 hr after incubation of 36 hr-CM from SKAPP or SH-SY5Y cells. The media from SKAPP cells showed significant difference in their ability to inhibit tumor cell proliferation compared to the media from control SH-SY5Y cells, as indicated by * P < 0.05. (C and D) SKAPP and control SKNSH cells were grown for 36 hr, 60 hr and 84 hr for incubation with tumor cells. The number of tumor cells was measured by BLI assay after 24 hr of incubation. The inhibitory effect of media on MDA-MB231-L cells (C) and B16F-L cells (D) was stronger than those media from shorter period of conditioning. The difference is statistically significant, * P < 0.05. All values represent means ± SEM (n = 6).