Objective       To determine the effect of co-culturing with osteoblast cell line MC3T3-E1 on the osteomimicry and proliferation in the osteolytic breast cancer cell line MDA-MB-231.       Methods       MDA-MB-231 cells were co-cultured with osteoblastic progenitor cells MC3T3-E1 in Transwell chamber in which MC3T3-E1 osteoblasts were inoculated in the upper chamber

while the same number of MDA-MB-231 cells in the lower chamber. In the control group

the same number and density of MDA-MB-231 cells were cultured in the upper and lower chambers

respectively. Real-time quantitative PCR and Western blotting were used to observe the expression of osteocalcin (OCN)

osteopontin (OPN)

and osteoprotegerin (OPG) at mRNA and protein levels. Cell Counting Kit-8 (CCK-8) was employed to detect the proliferation in the 2 groups. Crystal violet staining was adopted to observe the difference of cell colony between the 2 groups.       Results      Compared with the control group

the expression levels of OPG

OPN and OCN were all increased at mRNA and protein levels in the experimental group (P0.05). The proliferation of MDA-MB-231 was better in experimental group than the control group (P0.01). Cell colony of MDA-MB-231 cells was better in the experimental group than the control group.       Conclusion      Short-term co-culturing with MC3T3-E1 cells promotes breast cancer MDA-MB-231 cells to form osteomimicry

and enhances the cell proliferation and colony formation at the same time.