Previous studies have demonstrated that the C-terminal of E1A binding proteins (CtBPs) influences tumorigenesis by participating in cell signal transduction in various human malignancies. However, the detailed expression patterns of CtBP isoforms in human osteosarcoma (OS) and the molecular mechanisms of CtBP involvement in tumor cell phenotypes requires further investigation. In the present study, the expression patterns of CtBP2 in OS cells and tissues were explored by immunohistochemistry. Fetal osteoblast cells were transfected with a eukaryotic expression plasmid to overexpress CtBP2, and the endogenous CtBP2 in OS cells was silenced via a short hairpin RNA. These transfections were validated and the phosphorylation levels of the JAK1/Stat3 signaling pathway were explored via western blotting. Furthermore, the malignant phenotype of OS cells was evaluated via a Cell Counting Kit-8 assay, cell colony formation assay, cell migration assay and scratch wound healing assay. The results revealed that the expression of CtBP2, but not CtBP1, was upregulated in OS tissue samples and the elevated expression level of CtBP2 was notably associated with distant metastasis. CtBP2 was demonstrated to modulate cell migration and invasion via JAK1/Stat3 signaling pathway in fetal osteoblast cells. In addition, genetic silencing of CtBP2 expression in OS cells notably reduced cell migration abilities and the phosphorylation of the JAK1/Stat3 pathway. In summary, the present studies revealed that the loss of CtBP2 constrained distant metastasis through the JAK1/Stat3 pathway in OS, suggesting that targeting CtBP2 may be a practical anti-tumor approach to prevent OS tumor progression.

中文翻译：

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E1A结合蛋白2的C末端通过JAK1 / Stat3信号传导促进骨肉瘤细胞的恶性肿瘤。

先前的研究表明，E1A结合蛋白（CtBPs）的C末端通过参与各种人类恶性肿瘤中的细胞信号转导来影响肿瘤发生。但是，CtBP亚型在人类骨肉瘤（OS）中的详细表达模式以及CtBP参与肿瘤细胞表型的分子机制尚需进一步研究。在本研究中，通过免疫组织化学探索了CtBP2在OS细胞和组织中的表达模式。用真核表达质粒转染胎儿成骨细胞以过度表达CtBP2，并通过短发夹RNA沉默OS细胞中的内源性CtBP2。验证了这些转染，并通过蛋白质印迹探讨了JAK1 / Stat3信号通路的磷酸化水平。此外，OS细胞的恶性表型通过Cell Counting Kit-8测定法，细胞集落形成测定法，细胞迁移测定法和刮伤愈合测定法进行评估。结果显示，OS组织样品中CtBP2的表达被上调，而CtBP2的表达却与远处转移有关，而CtBP2的表达却没有升高。CtBP2被证明通过JAK1 / Stat3信号通路调节胎儿成骨细胞中的细胞迁移和侵袭。另外，OS细胞中CtBP2表达的遗传沉默显着降低了细胞迁移能力和JAK1 / Stat3途径的磷酸化。总之，本研究表明，CtBP2的缺失通过OS中的JAK1 / Stat3途径限制了远处转移，