Department of Orthopedics, The Affiliated Hospital of Guizhou Medical University, Guiyang, 550009, Guizhou, China.
School of Basic Medicine, Guizhou Medical University, Guiyang, 550009, Guizhou, China.
Cell Commun Signal. 2023 Mar 2;21(1):46. doi: 10.1186/s12964-023-01064-w.
Early metastasis is a hallmark of osteosarcoma (OS), a highly common type of malignant tumor. Members of the potassium inwardly rectifying channel family exert oncogenic effects in various cancers. However, the role of the potassium inwardly rectifying channel subfamily J member 2 (KCNJ2) in OS is unclear.
The expression of KCNJ2 in OS tissues and cell lines was measured using bioinformatic analysis, immunohistochemistry, and western blotting. Wound-healing assays, Transwell assays, and lung metastasis models were used to analyze the effects of KCNJ2 on mobility of OS cells. The molecular mechanisms linking KCNJ2 and HIF1α in OS were explored by mass spectrometry analysis, immunoprecipitation, ubiquitination detection, and chromatin-immunoprecipitation quantitative real-time polymerase chain reaction.
KCNJ2 was found to be overexpressed in advanced-stage OS tissues, as well as in cells with high metastatic potential. High expression of KCNJ2 was associated with a shorter survival rate of OS patients. KCNJ2-inhibition repressed the metastasis of OS cells, whereas KCNJ2-elevation induced the opposite effects. Mechanistically, KCNJ2 binds to HIF1α and inhibits its ubiquitination, thus increasing the expression of HIF1α. Interestingly, HIF1α binds directly to the KCNJ2 promoter and increases its transcription under hypoxic conditions.
Taken together, our results indicated that a KCNJ2/HIF1α positive feedback loop exists in OS tissues, which significantly promotes OS cell metastasis. This evidence may contribute to the diagnosis and treatment of OS. Video Abstract.
早期转移是骨肉瘤（OS）的一个标志，骨肉瘤是一种高度常见的恶性肿瘤。钾离子内向整流通道家族的成员在各种癌症中发挥致癌作用。然而，钾离子内向整流通道亚家族 J 成员 2（KCNJ2）在骨肉瘤中的作用尚不清楚。
使用生物信息学分析、免疫组织化学和 Western blot 检测 KCNJ2 在骨肉瘤组织和细胞系中的表达。划痕愈合试验、Transwell 试验和肺转移模型用于分析 KCNJ2 对骨肉瘤细胞迁移能力的影响。通过质谱分析、免疫沉淀、泛素化检测和染色质免疫沉淀定量实时聚合酶链反应探索 KCNJ2 与骨肉瘤中 HIF1α 之间的分子机制。
发现 KCNJ2 在晚期骨肉瘤组织以及具有高转移潜能的细胞中过度表达。KCNJ2 高表达与骨肉瘤患者的生存率缩短相关。KCNJ2 抑制抑制了骨肉瘤细胞的转移，而 KCNJ2 升高则诱导了相反的效果。机制上，KCNJ2 与 HIF1α 结合并抑制其泛素化，从而增加 HIF1α 的表达。有趣的是，HIF1α 在低氧条件下直接结合到 KCNJ2 启动子并增加其转录。
总之，我们的结果表明，骨肉瘤组织中存在 KCNJ2/HIF1α 正反馈回路，可显著促进骨肉瘤细胞转移。这一证据可能有助于骨肉瘤的诊断和治疗。视频摘要。
