Background and purpose:MicroRNA(miRNA) is a class of small non-coding RNA playing an important regulatory role in many tumors. This study investigated which miRNA might negatively regulate the expression of Aurora-B in osteosarcoma cells, and to lay the foundation for the further investigation of the effort and regulation of Aurora-B in osteosarcoma malignant phenotype.Methods:Bioinformatics prediction software (http://www.targetscan.org) and luciferase assays were used to investigate which miRNA might target to modulate the Aurora-B. Real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and Western blot assay were used to further verify which miRNA could negative regulate the expression ofAurora-B gene.Results:Bioinformatics prediction showed let-7 family have the possibility to modulate the expression of Aurora-B; Luciferase assays showed thatAurora-B might be the target gene of let-7a/b/c/d/e/f/g/i; RTFQ-PCR and Western blot analysis testiifed that both the expression levels of Aurora-B mRNA and Aurora-B protein were signiifcantly decreased in Let-7a/g/i up-regulated U2-OS and HOS cells, compared to the cells in the negative control group; but in Let-7b/c/d/e/f up-regulated U2-OS and HOS cells, the expression levels of Aurora-B mRNA and Aurora-B protein have no signiifcant difference, compared to the cells in the negative control group.Conclusion:Let-7a/g/i may downregulate the expression of Aurora-B in human osteosarcoma cells.

Objective To investigate the effects of down-regulating phosphorylated human epidermal growth factor receptor 2 (HER2) on the proliferation and metastasis in human osteosarcoma cells (U2-OS) in vitro. Methods Various concentrations of HER2 phosphorylation inhibitor lapatinib ditosylate (5, 10, 20, 30 and 40 μmol/L) were adopted to deal with U2-OS. MTT assay was performed to evaluate the cell proliferation during various times (24, 48 and 72 h), and the IC50 value in 24 h was calculated. The value of 10μmol/L (IC50=22.15μmol/L) was chosen to deal with U2-OS cells. The expres-sion level of phosphorylated HER2 (p-HER2) was measured by Western blot assay. The cell migration and invasion abilities were detected by Wound healing and Transwell invasion assays. Results The cell proliferation of U2-OS was significantly inhibited by HER2 phosphorylation inhibitor lapatinib ditosylate in a concentration- and time-dependent manner. During 24 hours, the p-HER2 level was significantly lower in lapatinib ditosylate group than that of negative control group (0.093± 0.033 vs 0.306±0.033), the cell migration rate was significantly lower in lapatinib ditosylate group than that of negative con-trol group (32.70%±3.00%and 94.52%±4.76%), and the trans-membrane cells were significantly lower than those of nega-tive control group (37/HP±5/HP and 85/HP±10/HP), respectively. Conclusion The down-regulating p-HER2 in U2-OS could efficiently inhibit the cell proliferation, migration and invasion in vitro. HER2 has the potential to become a molecular target for anti-osteosarcoma metastasis.

Objective:To discuss the pathological relationship between P33ING1 and stomach cancer and its clinical significance. Methods: In 71 cases of stomach cancer specimen, twelve cases of gas tric mu cous membrane atypical hyperplasia tissues and 18 cases of normal gastric mucous membrane tissue（as control）,the expression of P33ING1 were detected b y EnVision immunohistochemical method,while the expression of P53 and Bcl -2 in stomach cancer were also detected. Results: P33IN G1 expression in mucous membrane atypical hyperplasia group and control group was positive, the expression in stomach cancer group was extremely low(62.0%，44 /71), significantly different from the other 2 groups(P<0.01).P33ING1 expression in stomach cancer was related to the tumor growth, lymph node meta s tasis and tumor polarization (P<0.01), P53 expression was related to tumor s ize, growth and lymph node metastasis (P<0.01). Bcl-2 expression was relate d to lymph node metatasis and tumor polarization.The expression of P33ING1 was related to that of P53 in stomach cancer(P<0.05),while had no relation with that of Bcl-2.Conclusion:P33ING1 may play an importa nt role in the occurrance and development of stomach cancer.It's very important to detect the expression of P33ING1 and P53 simultaneously.