Neuroblastoma (NB) is responsible for 15% of all childhood cancer deaths. Despite advances in treatment and disease management, the overall 5-year survival rates remain poor in high-risk disease (25-40%). It is well known that miR-145 functions as a tumor suppressor in several types of cancer. However, the impact of miR-145 on NB is still ambiguous. Our aim was to investigate the potential tumor suppressive role and mechanisms of miR-145 in high-risk neuroblastoma. Expression levels of miR-145 in tissues and cells were determined using RT-qPCR. The effect of miR-145 on cell viability was evaluated using MTT assays, apoptosis levels were determined using TUNEL staining, and the MTDH protein expression was determined using western blot and RT-PCR. Luciferase reporter plasmids were constructed to confirm direct targeting for MTDH. The results showed that miR-145 expression was significantly lower in high-risk MYCN amplified (MNA) tumors and low miR-145 expression was associated with worse EFS and OS in our cohort. Over-expression of miR-145 reduced cell viability and increased apoptosis in SH-SY-5Y cells. We identified MTDH as a direct target for miR-145 in SH-SY-5Y cells. Targeting MTDH has the similar results as miR-145 overexpression. Our findings suggest that low miR-145 expression was associated with poor prognosis in patients with NB, and the overexpression of miR-145 inhibited NB cells growth by down-regulating MTDH, thus providing a potential target for the development of microRNA-based approach for NB therapy.

中文翻译：

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MicroRNA-145过表达在体外和体内抑制神经母细胞瘤的肿瘤发生。

神经母细胞瘤（NB）占所有儿童期癌症死亡的15％。尽管在治疗和疾病管理方面取得了进步，但高危疾病的总体5年生存率仍然很低（25-40％）。众所周知，miR-145在几种类型的癌症中起着抑癌作用。但是，miR-145对NB的影响仍然不明确。我们的目的是研究miR-145在高危神经母细胞瘤中的潜在抑癌作用及其机制。使用RT-qPCR测定miR-145在组织和细胞中的表达水平。使用MTT分析评估miR-145对细胞生存力的影响，使用TUNEL染色确定凋亡水平，并使用Western blot和RT-PCR确定MTDH蛋白表达。构建荧光素酶报道质粒以证实直接靶向MTDH。结果表明，在我们的队列中，高风险MYCN扩增（MNA）肿瘤中miR-145表达明显较低，而miR-145低表达与较差的EFS和OS相关。miR-145的过表达降低了SH-SY-5Y细胞的细胞活力并增加了细胞凋亡。我们确定MTDH作为SH-SY-5Y细胞中miR-145的直接靶标。靶向MTDH具有与miR-145过表达相似的结果。我们的研究结果表明，miR-145的低表达与NB患者的预后不良有关，miR-145的过表达通过下调MTDH抑制了NB细胞的生长，从而为开发基于microRNA的方法提供了潜在的靶点。 NB疗法。