Expression And Clinical Significance Of FZD10 In Osteosarcoma And Preliminary Research On Effects Of FZD10 On Biological Function Of Human Osteosarcoma Cell Line SOSP-9607

Background:Osteosarcoma is the most common primary malignant bone tumor that is usually contracted by children and young. The characters of osteosarcoma are high affection, early metastasis. About 85%～90% of the cases who have this disease have been in metastasis period when they begin to recognize they have this disease and metastasis is the fist reason for treatment failure which cause the death of sufferers.[1-3] The mechanism of osteosarcoma is still unknown as yet. Our laboratory established two pair cell lines with different metastasis capability, which call F4 and F5M2. F4 had low metastasis capability but F5M2 had high metastatic capability. We found some genes which express different between the two pair cell lines by microarray. One of this genes is FZD10 which expression significantly increased in high metastatic cell lines F5M2 but significantly decreased in low metastatic cell lines F4. There is hint shows that FZD10 has positive relationship with osteosarcoma.Wnt signaling plays an important role in many processes of life, regulating early embryonic development, cell differentiation, cell proliferation and growth. Abnormal expression or activation of Wnt signaling pathway will result in many diseases and tumors. FZD10 is a member of Frizzle gene family which plays an important role in Wnt signaling. It codes receptor related protein of Wnt signaling.Objective:To investigate the expression of FZD10 in osteosarcoma and their clinical significance; To describe the effects of FZD10 on biological function of human osteosarcoma cell line SOSP-9607 in order to further promote the clinical application of miR-34a in osteosarcoma prognosis and treatment.Methods:1. The expression of FZD10 protein was detected by the SP immunohistochemical method in 69 cases of osteosarcoma and 35 cases of osteochondroma. It's relationship to osteosarcoma clinical pathology and prognosis was analyzed statistically.2. RNAi was used to inhibit the expression and function of FZD10. Western-blot was used to detect the expression of FZD10 after RNAi.3. Transwell experiment was used to examine the effect of FZD10 to the invasion of SOSP-9607 cells.4. MTT assay was used to examine the the effect of FZD10 to the proliferation of SOSP-9607 cells.5. The cell cycles and the cell apoptosis were measured by flow cytometry. Results:1. The positive rates of FZD10 were 89.9% and 5.7% in osteosarcoma and osteochondroma, respectively (P<0.01). The expression of FZD10 was correlated to Enneking grade, Price grade, WHO classification and prognosis.2. The expression of FZD10 was inhibited successfully by RNAi.3. The Results of MTT assay show that SOSP-9607 cell proliferation in a dose-dependent manner in the experiment group, while the control group had no obvious effect on cell proliferation; The Results of transwell show that in the experiment group the invasion and migration of SOSP-9607 cells were significantly inhibited.4. The apoptosis ratio of experimental group was obviously higher than the apoptosis ratio of control group. The inhibitor of FZD10 increased the cell ratio of G0/G1 phase, simultaneously decreased significantly the cell ratios of G2/M phase and S phase.Conclusion:1. The expression of FZD10 protein is closely correlated to malignant degree. It may serve as a valuable marker for diagnosis and an indicator to predict the prognosis of osteosarcoma.2. The inhibitor of FZD10 significantly inhibits the proliferation, invasion and migration of SOSP-9607 cells, and also significantly enhanced the apoptosis ratio of SOSP-9607 cells and caused the cell cycle retention of SOSP-9607.