Xu Enjie, Huang Zhen, Zhu Kunpeng, Hu Jianping, Ma Xiaolong, Wang Yongjie, Zhu Jiazhuang, Zhang Chunlin
Department of Orthopedic Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, PR China.
Institute of Bone Tumor Affiliated to Tongji University School of Medicine, Shanghai, 200072, PR China.
Int J Biol Sci. 2025 Feb 18;21(5):2083-2100. doi: 10.7150/ijbs.93678. eCollection 2025.
Dedifferentiation of osteosarcoma cells leads to poor prognosis. We plan to identify the key molecules that are involved in cell dedifferentiation and explore how they promote the pulmonary metastasis of osteosarcoma cells. We performed a sphere formation assay and confirmed that the spheroid cells could be redifferentiated into osteoblasts, adipocytes, and chondrocytes in specific medium, and the stem cell-like markers Stro-1 and CD117 were detected on the cell surface, which indicated that the spheroid cells were dedifferentiated cells. Thrombospondin 1 (THBS1) and ITGAs were identified as the key molecules in dedifferentiation through mRNA-seq and analysis, and osteosarcoma patients with higher THBS1 expression had a worse prognosis than those with lower THBS1 expression. THBS1 promotes the accumulation of ITGA1 and ITGA6 on the cell membrane in the early phase of dedifferentiation, thereby increasing the phosphorylation of FAK, RasGRF1, and MLC2 in the cytoplasm and promoting cytoskeleton remodeling. Our results suggest that THBS1 promotes cell dedifferentiation and pulmonary metastasis by promoting cytoskeletal remodeling and that ITGA1 and ITGA6 play important roles in mediating extracellular to intracellular signals; this mediating effect takes place mainly in the early phase of dedifferentiation.
骨肉瘤细胞的去分化导致预后不良。我们计划鉴定参与细胞去分化的关键分子，并探索它们如何促进骨肉瘤细胞的肺转移。我们进行了成球试验，证实球体细胞可在特定培养基中重新分化为成骨细胞、脂肪细胞和软骨细胞，并且在细胞表面检测到干细胞样标志物Stro-1和CD117，这表明球体细胞是去分化细胞。通过mRNA测序和分析，血小板反应蛋白1（THBS1）和整合素α亚基（ITGAs）被确定为去分化中的关键分子，THBS1表达较高的骨肉瘤患者的预后比THBS1表达较低的患者更差。THBS1在去分化早期促进ITGA1和ITGA6在细胞膜上的积累，从而增加细胞质中粘着斑激酶（FAK）、Ras鸟嘌呤核苷酸释放因子1（RasGRF1）和肌球蛋白轻链2（MLC2）的磷酸化，并促进细胞骨架重塑。我们的结果表明，THBS1通过促进细胞骨架重塑来促进细胞去分化和肺转移，并且ITGA1和ITGA6在介导细胞外到细胞内信号中起重要作用；这种介导作用主要发生在去分化的早期阶段。
