骨桥蛋白对细胞生存的多重作用

骨桥蛋白(osteopontin, OPN)作为一种分泌性蛋白质广泛存在于多种组织细胞中，不仅调控肿瘤细胞的转移、侵袭和增殖，也在炎症反应、血管再生等生理过程中发挥作用。OPN通过与受体结合直接或间接地激活细胞内信号途径，介导细胞与细胞、细胞与细胞外基质之间的相互作用，从而参与调控细胞的生存。大量实验证实，OPN能够促进细胞的增殖，抑制细胞凋亡，尤其是对于肿瘤细胞。但在有些细胞中，OPN对细胞命运的影响却恰恰相反。本文综述了OPN在不同条件下对细胞存活、活化和增殖，细胞自噬和细胞凋亡的多重作用及其作用途径，为进一步研究OPN对不同细胞作用的受体及其信号网络机制提供重要理论基础。

Multiple Effects of Osteopontin on Cell Survival

Osteopontin (OPN), as a highly modified extracellular matrix glycophosphoprotein, was widely distributed in various tissues and cells. It has been revealed to participate not only in metastasis, invasion and proliferation of tumor cells, but also in inflammation, angiogenesis and other physiological processes. OPN mediates the cell-cell and cell-extracellular matrix interactions through binding its receptors to regulate cell survival. Extensive studies have indicated that OPN promotes cell proliferation and inhibit apoptosis, especially that of tumor cells. However, several recent studies have elucidated its opposite effects on several kinds of cells. This review summarized the multiple regulatory roles of OPN in cell survival, activation and proliferation, autophagy and apoptosis in different circumstances, which will lay a theoretical basis for further study on the effects of OPN on different receptors and signaling networks in various cells.