Conditioned medium of lung cancer cells stimulates the proliferation of osteoblastic cells but inhibits their differentiation

Objective: To study the effects of A549 CM (conditioned medium) on the proliferation, differentiation and mineralization of pre-osteoblastic MC3T3-E1 Subclone 14 cells. Methods: The CM of lung cancer A549 cells was collected. MC3T3-E1 Subclone 14 cells were incubated with culture medium containing 10% A549 CM or 20% A549 CM. The proliferation of MC3T3-E1 Subclone 14 cells was detected by CCK-8 (cell counting kit-8) method. The ALP (alkaline phosphatase) activity of MC3T3-E1 Subclone 14 cells was measured by ALP kit. The mineralization of MC3T3-E1 Subclone 14 cells was detected by alizarin red staining. The expression levels of ALP, OCN (osteocalcin), Col1α1 (collagen typeⅠalpha 1) and RUNX2 (runt-related transcription factor 2) mRNAs were detected by real-time fluorescence quantitative-PCR. Results: The proliferation rates of MC3T3-E1 Subclone 14 cells cultured in 10% A549 CM or 20% A549 CM for 24 and 48 h were higher than those of the cells cultured without A549 CM (as the control cells) (P < 0.05), and the ALP activities were lower than those of the control cells (P < 0.05). The number and the area of mineralization nodes of MC3T3-E1 Subclone 14 cells cultured with 10% A549 CM or 20% A549 CM were all less than those of the control cells (P < 0.05). The expression levels of ALP, OCN, Col1α1 and RUNX2 mRNAs in MC3T3-E1 Subclone 14 cells cultured with A549 CM were lower as compared with the control cells (P < 0.05). Conclusion: The CM of lung cancer A549 cells can promote the proliferation of MC3T3-E1 Subclone 14 cells and inhibit their differentiation and mineralization. DOI:10.3781/j.issn.1000-7431.2012.11.003