Roberto Gabriela Molinari, Vieira Gabriela Maciel, Delsin Lara Elis Alberici, Silva Marcela de Oliveira, Hakime Rodrigo Guedes, Engel Edgard Eduard, Scrideli Carlos Alberto, Tone Luiz Gonzaga, Brassesco María Sol
Regional Blood Center, Ribeirão Preto School of Medicine, University of São Paulo, Av. Bandeirantes, 3,900, Bairro Monte Alegre, Ribeirão Preto, SP, CEP 14040-901, Brazil.
Department of Genetics, Ribeirão Preto School of Medicine, University of São Paulo, Av. Bandeirantes, 3,900, Bairro Monte Alegre, Ribeirão Preto, SP, CEP 14040-901, Brazil.
Cancer Genet. 2019 Jan;230:21-27. doi: 10.1016/j.cancergen.2018.11.003. Epub 2018 Nov 13.
Overall survival of Ewing sarcoma (EWS) remains poor and less than 30% of patients with metastatic or recurrent disease survive despite current treatments. Thus, there is a constant search for new biomarkers for diagnosis, prognosis and prediction of therapy. Numerous studies have reported the abnormal expression of miR-708-5p in tumors of different origins. However, its role in EWS remains unclear.
qRT-PCR was performed in nineteen consecutive EWS samples and twelve non-tumor bone samples from age-matched controls. Functional assays were performed in SK-ES-1 cells transfected with miR-708 lentiviral-based vectors and results analyzed in terms of clonogenicity, migration, invasion and western blot.
We show that miR-708-5p is downregulated in EWS tissues though no associations with any prognostic features such as HUVOS grade, event or survival were found in our cohort. Nonetheless, expression levels of this micro-RNA were inversely associated with the presence of the EWS/FLI1 translocation. When miR-708-5p was transfected into the SK-ES-1 cell line, it did not affect migration or clonogenicity, but promoted a significant increase on the invasive potential of cells endorsed with high expression of MMP2.
Taken together, our results suggest that despite downregulated in EWS samples, this miRNA might represent a secondary genetic alteration derived from the pleiotropic cellular effects of the abnormal EWS/FLI1 transcription factor that does not affect tumor growth but instead, is related with the promotion of tumor invasion, not being suitable for future therapeutic intervention.
尤因肉瘤（EWS）患者的总体生存率仍然很低，尽管目前有多种治疗方法，但转移性或复发性疾病患者的生存率仍不到30%。因此，人们一直在寻找用于诊断、预后评估和治疗预测的新生物标志物。许多研究报告了miR-708-5p在不同起源肿瘤中的异常表达。然而，其在EWS中的作用仍不清楚。
对19例连续的EWS样本和12例来自年龄匹配对照的非肿瘤骨样本进行qRT-PCR。在转染了基于慢病毒载体的miR-708的SK-ES-1细胞中进行功能分析，并从克隆形成、迁移、侵袭和蛋白质免疫印迹方面分析结果。
我们发现miR-708-5p在EWS组织中表达下调，尽管在我们的队列中未发现其与任何预后特征（如HUVOS分级、事件或生存率）相关。尽管如此，这种微小RNA的表达水平与EWS/FLI1易位的存在呈负相关。当将miR-708-5p转染到SK-ES-1细胞系中时，它不影响迁移或克隆形成，但显著促进了高表达MMP2的细胞的侵袭潜能。
综上所述，我们的结果表明，尽管在EWS样本中表达下调，但这种miRNA可能代表一种继发的基因改变，它源自异常的EWS/FLI1转录因子的多效性细胞效应，不影响肿瘤生长，而是与肿瘤侵袭的促进有关，不适用于未来的治疗干预。
