Department of Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600 Yishan Road, Shanghai 200233, China.
Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
EBioMedicine. 2020 Sep;59:102955. doi: 10.1016/j.ebiom.2020.102955. Epub 2020 Aug 24.
Metastasis is the leading cause of death in patients with osteosarcoma. Some of these patients fail to respond to chemotherapy and die of metastasis within a short period. Therefore, it is important to identify novel biomarkers to improve the diagnosis and treatment of osteosarcoma. TRIM7 is a member of the tripartite motif (TRIM) family protein that is involved in various pathological conditions including cancer; however, its role in osteosarcoma remains elusive.
Cell proliferation, invasion and migration were measured by CCK-8 and Transwell. Immunoprecipitation and mass spectrometry analysis were used to identify candidate proteins associated with TRIM7. Immunoprecipitation, immunofluorescence, pull down and ubiquitination assay were performed to examine the regulation between TRIM7 and its candidate protein. m6A modification of TRIM7 was measured by RNA immunoprecipitation.
TRIM7 expression was upregulated in osteosarcoma tissues and was an independent risk factor in predicting poor prognosis. TRIM7 regulates osteosarcoma cell migration and invasion through ubiquitination of breast cancer metastasis suppressor 1 (BRMS1). Moreover, chemoresistance was readily observed in osteosarcoma cells and in patient-derived xenograft (PDX) mice with higher TRIM7 levels. Loss of TRIM7 m6A modification was observed in osteosarcoma tissues. METTL3 and YTHDF2 were the main factors involved in the aberrant m6A modification of TRIM7.
Overall, our findings show that TRIM7 plays a key role in regulating metastasis and chemoresistance in osteosarcoma through ubiquitination of BRMS1.
This work was financially supported by grants of NSFC (81001192, 81672658 and 81972521) and National Key Research Project of Science and Technology Ministry (2016YFC0106204).
转移是骨肉瘤患者死亡的主要原因。其中一些患者对化疗无反应，在短时间内死于转移。因此，识别新的生物标志物对于改善骨肉瘤的诊断和治疗非常重要。TRIM7 是三部分基序 (TRIM) 家族蛋白的成员，参与包括癌症在内的各种病理状况；然而，其在骨肉瘤中的作用仍不清楚。
通过 CCK-8 和 Transwell 测定细胞增殖、侵袭和迁移。免疫沉淀和质谱分析用于鉴定与 TRIM7 相关的候选蛋白。免疫沉淀、免疫荧光、下拉和泛素化测定用于检查 TRIM7 与其候选蛋白之间的调节关系。通过 RNA 免疫沉淀测定 TRIM7 的 m6A 修饰。
TRIM7 在骨肉瘤组织中表达上调，是预测预后不良的独立危险因素。TRIM7 通过乳腺癌转移抑制因子 1 (BRMS1) 的泛素化调节骨肉瘤细胞的迁移和侵袭。此外，在具有较高 TRIM7 水平的骨肉瘤细胞和患者来源异种移植 (PDX) 小鼠中，很容易观察到化疗耐药性。在骨肉瘤组织中观察到 TRIM7 的 m6A 修饰缺失。METTL3 和 YTHDF2 是 TRIM7 异常 m6A 修饰的主要因素。
总体而言，我们的研究结果表明，TRIM7 通过 BRMS1 的泛素化在调节骨肉瘤的转移和化疗耐药性中起关键作用。
本工作得到了国家自然科学基金 (81001192、81672658 和 81972521) 和国家重点研发计划 (2016YFC0106204) 的资助。
