Research HER-2 Expression In Osteosarcoma And Screened Aptamer Method

Objectives: To investigate the expression and significance of HER-2 in human osteosarcomatous tissue. And screening with HER2-specific binding oligo nucleic acid aptamers by SELEX.Methods: 1. The expression of HER-2 in human Osteosarcoma tissue was assessed by standard immuno-histo-chemical staining. relevance of comparing different clinical parameters and HER-2 expression. 2. In vitro synthesized with a length of 78 bases containing 35 random nucleotides ss DNA library, Preparing secondary separation system ss DNA library by biotin-streptavidin beads, The Microporous as a medium was used to obtain with HER2-specific binding of DNA aptamers by SELEX, Detects affinity of the round ss DNA with the target protein HER2 using biotin- streptavidin-biotin- horseradish peroxidase system. The highest affinity aptamers group were cloned and sequenced. Finally, the paper on the use of biological software DNAMAN carried out an analysis of the structure and the secondary structure for aptamer group, while the highest affinity aptamer made further test for its specificity.Results: 1. A total of 80 cases of pathological specimens, there are 61 cases of osteosarcoma in HER-2 positive expression, The positive rate of osteosarcoma is 76.3%(61/80), Among different gender, age, tumor location, tumor diameter pathological expression of HER-2’s no difference was not statistically significant(P> 0.05), The HER-2 expression in the tissue of patients with TNM stage and lymph node metastasis significantly, and the difference was statistically significant(P <0.05). 2. After 12 rounds of screening, obtained aptamers that had high affinity with HER2 protein, it was number 9. affinity from the initial 0.18 to 0.86, increased by about 5 times. specificity results showed that: number 9 aptamer has a high specificity only with the HER2.Conclusion: 1. HER-2 expression in osteosarcoma abnormalities, and the development of osteosarcoma related, can be used as an independent osteosarcoma early detection and evaluation of biological indicators of prognosis. 2. After several rounds of screening successfully obtained osteosarcoma HER2 protein specifically recognizing single-stranded DNA aptamers, for the diagnosis and prognosis treatment of osteosarcoma has laid a solid foundation.