Résumé
Objective To investigate effects of different doses of recombinant human bone morphogenetic protein-2 (rhBMP-2) on vascular endothelial growth factor (VEGF) expression in fetal mouse osteoblasts.Methods Calvaria osteoblasts of fetal mice of 19 days were cultured.The effects of rhBMP-2 at different doses and different action times on VEGF expression patterns in fetal mouse osteoblasts were observed with reverse transcrip- tion-polymerase chain reaction (RT-PCR) and Western blot staining.Results In the present study,RT-PCR detected a steady expression of VEGF mRNA in the control fetal mouse osteoblasts.The levels of VEGF mRNA increased in an apparent biphasic manner with a maximum stimulation (about 2-fold above the control,P＜0.05 ) in both VEGF mRNA species observed at 300 ng/mL of rbBMP-2.After 48 h of rhBMP-2 treatment,the VEGF mRNA levels approached those in the control.The VEGF mRNA levels appeared to be biphasic in rhBMP-2-treated cultures,showing peak induction at 3 and 24 h and remaining elevated at 48 b.Compared with the individual control value at each time point,an apparent maximum increase (about 2.5-fold above the control,P＜0.05) occurred at 6 h.The second peak induction,about 2-fold above that in the control,occurred at about 36 h.Conclusions The expression of VEGF mRNA is steady in the control fetal mouse osteoblasts.RhBMP-2 can promote the expression of VEGF in dose-dependent and time-dependent manners.
Résumé
<p><b>OBJECTIVE</b>To evaluate the effects of transforming growth factor beta1 (TGFbeta1) autocrine blockage on proliferation activity and drug sensitivity of osteosarcoma. METHODS; Northern blot, MTT determination, and 3H thymidine incorporation were used to investigate the effects of antisense TGF beta1 gene on osteosarcoma.</p><p><b>RESULTS</b>The proliferation of osteosarcoma cells transfected by antisense TGF beta1 gene was suppressed markedly, and adriamycin sensitivity was significantly increased.</p><p><b>CONCLUSION</b>Blockage of osteosarcoma cells TGF beta1 autocrine loop inhibits cell proliferation and enhances chemotherapy sensitivity.</p>