Department of Traumatic Orthopedics, The Second Hospital of Dalian Medical University, Dalian, 116023, China.
Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, 410011, China.
Lab Invest. 2022 Aug;102(8):826-837. doi: 10.1038/s41374-021-00691-6. Epub 2022 Mar 24.
Osteosarcoma is a bone tumor that often affects children, adolescents and young people. Non-coding RNA activated by DNA damage (NORAD) can promote the proliferation of cancer cells in multiple tumors. Thus, the current study set out to explore the role of NORAD derived from extracellular vesicles (EVs) of bone mesenchymal stem cells (BMSCs) in osteosarcoma. First, NORAD was highly expressed in osteosarcoma cells and tissues, which might be associated with the progression and metastasis of osteosarcoma. We isolated EVs from the characterized BMSCs, and found that NORAD was transferred from BMSCs to osteosarcoma cells via EVs in the co-culture system. Consequently, NORAD delivered by BMSC-derived EVs promoted the proliferation and invasion of osteosarcoma cells. Subsequently, bioinformatics analyses suggested potential binding relationship between NORAD and microRNA-30c-5p (miR-30c-5p) as well as between miR-30c-5p and Krueppel-like factor 10 (KLF10), and the results of which were further verified by dual luciferase reporter gene assay, RNA immunoprecipitation, and RNA pull-down assay. Mechanistically, NORAD acted as a sponge of miR-30c-5p and up-regulated the expression of KLF10 where miR-30-c-5p mimic declined the effect induced by NORAD on cancer cells. The osteosarcoma cells were injected into mice to develop tumor growth and metastasis models. In these two models, injection of BMSC-EVs elevated NORAD expression and KLF10 but reduced miR-30c-5p expression, whereby suppressing tumor growth and lung metastasis. To conclude, BMSC-EVs deliver NORAD to osteosarcoma cells to regulate the miR-30c-5p/KLF10 axis, thereby accelerating the progression and metastasis of osteosarcoma.
骨肉瘤是一种常发生于儿童、青少年和年轻人的骨肿瘤。DNA 损伤激活的非编码 RNA（NORAD）可促进多种肿瘤中癌细胞的增殖。因此，本研究旨在探讨来源于骨髓间充质干细胞（BMSC）细胞外囊泡（EVs）的 NORAD 在骨肉瘤中的作用。首先，NORAD 在骨肉瘤细胞和组织中高表达，这可能与骨肉瘤的进展和转移有关。我们从特征明确的 BMSC 中分离出 EVs，并发现 NORAD 可通过共培养系统中的 EV 从 BMSC 转移到骨肉瘤细胞。因此，BMSC 衍生的 EV 递送的 NORAD 促进了骨肉瘤细胞的增殖和侵袭。随后，生物信息学分析提示 NORAD 与 microRNA-30c-5p（miR-30c-5p）以及 miR-30c-5p 与 Krueppel 样因子 10（KLF10）之间存在潜在的结合关系，双荧光素酶报告基因检测、RNA 免疫沉淀和 RNA 下拉实验进一步验证了这一结果。在机制上，NORAD 作为 miR-30c-5p 的海绵，上调了 KLF10 的表达，而 miR-30c-5p 模拟物则降低了 NORAD 对癌细胞的作用。将骨肉瘤细胞注射到小鼠体内以建立肿瘤生长和转移模型。在这两种模型中，BMSC-EVs 的注射增加了 NORAD 的表达和 KLF10，但降低了 miR-30c-5p 的表达，从而抑制了肿瘤的生长和肺转移。总之，BMSC-EVs 将 NORAD 递送至骨肉瘤细胞，调节 miR-30c-5p/KLF10 轴，从而加速骨肉瘤的进展和转移。
