Effect of human bone marrow mesenchymal stem cells conditioned medium on cell growth of prostate cancer cell line PC-3

Objective: To investigate the effect of human bone marrow mesenchymal stem cells (MSCs) conditioned medium (CM) on cell growth of prostate cancer cell line PC-3. Methods: MSCs were isolated and culture-expanded by using density gradient centrifugation from a healthy adult. When the passage 3 (P3) culture reached 80% confluence, the medium was changed to fresh medium. After 24-hour incubation, the supernatant (MSCs-CM) was collected. Then the PC-3 cells were incubated in fresh medium alone (as the control group) or in the medium supplemented with 50% MSCs-CM (as the CM group). The ultrastructure of PC-3 cells was observed under a transmission electron microscope. The cell viability was measured by WST-8 assay, and the cell cycle was analyzed by flow cytometry (FCM). Results: On day 4, the nucleus to cytoplasm ratio was lower and the number of organelles was much more in PC-3 cells in the CM group than those in the control group. The WST-8 assay showed that the absorbance values (on day 1, 3, 5 and 7) of the CM group were significantly higher than those in the control group (P＜0.01), except for the value on day 1 (P＞0.05). On day 4, the percentage of cells in G0/G1 phase was decreased while which in S+G2/M phase was increased in the CM group compared with those in the control group (56.20%±0.78% vs 68.54%±1.21%, P＜0.01; 43.80%±0.77% vs 31.46%±1.20%, P＜0.01). Conclusion: MSCs-CM can promote the proliferation of PC-3 cells through accelerating G1 to S phase transition. DOI:10.3781/j.issn.1000-7431.2011.07.005