Department of Ophthalmology, Luoyang Central Hospital, Luoyang, Henan 471009, P.R. China.
Department of Ophthalmology, Linyi People's Hospital, Linyi, Shandong 276003, P.R. China.
Int J Oncol. 2018 Dec;53(6):2615-2626. doi: 10.3892/ijo.2018.4587. Epub 2018 Oct 9.
Retinoblastoma (RB) is a well‑vascularized tumor dependent on angiogenesis. The present study aimed to explore whether microRNA (miR)‑182 regulates cell viability, invasion and angiogenesis in RB via the phosphatidylinositol‑3‑OH kinase (PI3K)/protein kinase B (AKT) signaling pathway and by targeting cell adhesion molecule 2 (CADM2). The expression levels of miR‑182 and CADM2 were initially detected in RB tissues from patients with RB who underwent ophthalmectomy, and normal retinal tissues collected from other trauma patients who underwent eye enucleation. To determine whether CADM2 was targeted by miR‑182, a dual luciferase reporter assay was conducted. Subsequently, Y79 and WERI‑Rb‑1 RB cells were transfected with a miR‑182 mimic or miR‑182 inhibitor, or small interfering RNA against CADM2, in order to investigate the effects of miR‑182 on viability and invasion, which were detected using MTT and Transwell assays, respectively. In addition, to determine whether the regulatory mechanism underlying the effects of miR‑182 was associated with the PI3K/AKT signaling pathway, the expression levels of associated genes were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. A xenograft tumor model in nude mice was also established, in order to evaluate the effects of miR‑182 on tumor growth and angiogenesis. The results indicated that miR‑182 expression was increased and CADM2 expression was reduced in RB tissues; CADM2 was confirmed to be targeted and negatively regulated by miR‑182. When the expression of miR‑182 was downregulated, cell viability, invasion, tumor volume and angiogenesis were significantly decreased. Furthermore, the expression levels of PI3K/AKT signaling pathway‑associated genes were increased in response to miR‑182 overexpression or CADM2 silencing. Taken together, these results suggested that inhibition of miR‑182 may suppress cell viability, invasion and angiogenesis in RB through inactivation of the PI3K/AKT pathway and CADM2 upregulation. This mechanism may reveal a novel potential therapeutic target.
视网膜母细胞瘤 (RB) 是一种依赖血管生成的富血管肿瘤。本研究旨在探讨 microRNA (miR) -182 是否通过磷脂酰肌醇 3-羟激酶 (PI3K)/蛋白激酶 B (AKT) 信号通路并靶向细胞黏附分子 2 (CADM2) 调节 RB 中的细胞活力、侵袭和血管生成。最初检测了接受眼摘术的 RB 患者的 RB 组织和接受眼球切除术的其他创伤患者的正常视网膜组织中的 miR-182 和 CADM2 的表达水平。为了确定 CADM2 是否是 miR-182 的靶标，进行了双荧光素酶报告基因检测。随后，将 miR-182 模拟物或 miR-182 抑制剂或针对 CADM2 的小干扰 RNA 转染到 Y79 和 WERI-Rb-1 RB 细胞中，以分别通过 MTT 和 Transwell 测定法检测 miR-182 对活力和侵袭的影响。此外，为了确定 miR-182 作用的调节机制是否与 PI3K/AKT 信号通路有关，通过逆转录-定量聚合酶链反应和 Western blot 分析检测相关基因的表达水平。还建立了裸鼠异种移植肿瘤模型，以评估 miR-182 对肿瘤生长和血管生成的影响。结果表明，miR-182 在 RB 组织中表达增加，CADM2 表达减少；CADM2 被证实是受 miR-182 靶向和负调控的。当 miR-182 的表达下调时，细胞活力、侵袭、肿瘤体积和血管生成明显降低。此外，PI3K/AKT 信号通路相关基因的表达水平在 miR-182 过表达或 CADM2 沉默时增加。总之，这些结果表明，通过失活 PI3K/AKT 通路和上调 CADM2，抑制 miR-182 可能抑制 RB 中的细胞活力、侵袭和血管生成。该机制可能揭示了一个新的潜在治疗靶点。
