ABSTRACT
Objective:To investigate the influence of all-trans-retinoic acid (ATRA) on the proliferation and invasion of osteosarcoma 143B cells and its possible regulatory mechanism.Methods:Different concentrations of ATRA were used to treat human osteosarcoma 143B cells, and the optimal concentration and treatment time those affected cell proliferation were selected. The MTS method, Transwell migration and invasion experiments were used to detect the changes in the proliferation, migration and invasion of 143B cells after ATRA treatment. The real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot were used to detect the expression changes of miRNA-34a (miR-34a), E2F1 and Eag1 in osteosarcoma 143B cells after ATRA treatment. Then miR-34a was interfered and E2F1 was overexpressed, and the abilities of cell proliferation, invasion and migration abilities as well as the expression changes of miR-34a, E2F1 and Eag1 in 143B cells were detected.Results:The proliferation inhibition of 143B cells was most obvious when 143B cells were treated with 10 μmol/L ATRA for 72 h. The cell migration and invasion numbers when 143B cells were treated with 10 μmol/L ATRA for 72 h were lower than those in the negative control group [(73±3) cells vs. (182±5) cells, t = 21.46, P<0.01; (94±3) cells vs. (203±7) cells, t = 13.70, P<0.01]. 10 μmol/L ATRA could promote the expression of miR-34a in 143B cells and inhibit the expressions of Eag1 and E2F1 (all P<0.01). Compared with ATRA group, the ability of cell proliferation in ATRA+miR-34a interference group was restored after 72 h of treatment [cell survival rate (41.0±2.2)% vs. (25.0±3.6)%, t = 108.68, P<0.01]. Compared with ATRA group, the abilities of cell migration and invasion in ATRA+miR-34a interference group were restored [(122±14) cells vs. (64±10) cells, t = 21.06, P<0.01; (103±10) cells vs. (59±8) cells, t = 24.27, P<0.01), and the mRNA and protein expressions of Eag1 and E2F1 in cells were promoted (both P<0.01). Compared with ATRA group, the ability of cell proliferation in ATRA+E2F1 overexpression group was restored [cell survival rate (40.0±3.4)% vs. (24.0±3.1)%, t = 108.74, P<0.01]; the abilities of cell migration and invasion in ATRA+E2F1 overexpression group were restored [(78±12) cells vs. (29±8) cells, t = 13.52, P<0.01; (75±12) cells vs. (49±10) cells, t = 6.28, P<0.01], and the mRNA and protein expressions of Eag1 and E2F1 in cells were promoted (both P<0.01). Conclusion:ATRA inhibits the proliferation and invasion of osteosarcoma cells via regulating miR-34a-E2F1-Eag1 signaling pathway, and it may become one of the effective treatment drugs for osteosarcoma.
ABSTRACT
Objective: To observe the change of stromal cell-derived factor 1α/cysteine X cysteine receptor 4 (SDF-1α/CXCR4) signaling pathway during the process of axial stress stimulation promoting bone regeneration, and to further explore its mechanism. Methods: A total of 72 male New Zealand white rabbits were selected to prepare the single cortical bone defect in diameter of 8 mm at the proximal end of the right tibia that repaired with deproteinized cancellous bone. All models were randomly divided into 3 groups ( n=24). Group A was treated with intraperitoneally injection of PBS; Group B was treated with stress stimulation and intraperitoneally injection of PBS; Group C was treated with stress stimulation and intraperitoneally injection of AMD3100 solution. The X-ray films were taken and Lane-Sandhu scores of bone healing were scored at 2, 4, 8, and 12 weeks after operation, while specimens were harvested for HE staining, immunohistochemical staining of vascular endothelial growth factor (VEGF) and CXCR4, and Western blot (SDF-1α and CXCR4). The bone healing area was scanned by Micro-CT at 12 weeks after operation, and the volume and density of new bone were calculated. Results: X-ray film showed that the Lane-Sandhu scores of bone healing in group B were significantly higher than those in groups A and C at 4, 8, and 12 weeks after operation ( P<0.05). Micro-CT scan showed that the bone defect was repaired in group B and the pulp cavity was re-passed at 12 weeks after operation. The volume and density of new bone were higher in group B than in groups A and C ( P<0.05). HE staining showed that the new bone growth in bone defect area and the degradation of scaffolds were faster in group B than in groups A and C after 4 weeks. The immunohistochemical staining showed that the expressions of VEGF and CXCR4 in 3 groups reached the peak at 4 weeks, and group B was higher than groups A and C ( P<0.05). Western blot analysis showed that the expressions of SDF-1α and CXCR4 in group B were significantly higher than those in groups A and C at 4 and 8 weeks after operation ( P<0.05). Conclusion: Axial stress stimulation can promote the expression of SDF-1α in bone defect tissue, activate and regulate the CXCR4 signal collected by marrow mesenchymal stem cells, and accelerate bone regeneration in bone defect area.