Faculty of Medicine, Department of Surgery and Orthopedics, São Paulo State University (UNESP), Botucatu, Brazil.
Faculty of Medicine Experimental Research Unity (UNIPEX), São Paulo State University (UNESP), Botucatu, Brazil.
Cell Physiol Biochem. 2021 Jan 6;55(S2):1-12. doi: 10.33594/000000320.
BACKGROUND/AIMS: Lung carcinoids are uncommon neuroendocrine tumours. Molecular features of lung carcinoids have been poorly defined. microRNAs (miRNAs) are potent gene expression regulators with important roles in cancer development and progression. However, little is known on the role of miRNAs in the pathogenesis of lung carcinoids. Our goals were to identify commonly deregulated miRNAs in a rare case of lung carcinoid of typical histology with metastasis, as well as map miRNA target genes in pathways potentially associated with disease development and progression.
miRNA expression profiles were assessed using the TaqMan Low Density Arrays, which is a platform including 384 miRNAs. miRNA profiles were generated in the tumor and its corresponding lymph node metastasis, compared to reference normal lung tissues. Furthermore, miRNA expression was validated in a separate, publicly available external dataset (n=19 typical lung carcinoids; 2/19 were metastatic tumors, compared to six normal lung tissues, GSE77380). Following this analysis, computational tools were applied for data interpretation. miRTarBase was used to determine miRNA-target genes, followed by ToppGene Suite analysis to identify pathways and biological functions. In addition, the expression of genes targeted by miRNAs was validated in a second, separate external dataset (n=13 tumour samples, GSE35679). GEO2R data analysis tool was used in both validation analyses (miRNAs and genes).
We identified 15 commonly significantly downregulated miRNAs (fold change, FC≥2 and p<0.05) in the tumour and its paired metastasis, with further decreasing levels in the metastatic lesion. Downregulation of miR-126-3p and miR-146b-5p was validated in the external dataset GSE77380. In addition, SOX2 and TCF4 genes, targeted by miR-126-3p, were consistently overexpressed in a subset of six typical lung carcinoids from the external dataset GSE35679. Pathways analysis showed that miRNAs miR-126-3p and miR-146b-5p target genes with a role in the regulation of adaptive immune response.
Our results contribute to the identification of miRNA expression changes in a typical lung carcinoid and its corresponding lymph node metastasis. Down-regulated levels of miR-126-3p and miR-146b-5p and target gene over-expression could play a role in the progression of this case of primary typical lung carcinoid to regional metastasis. Identified miRNAs and target genes are potential candidates for validation in a larger number of cases.
背景/目的：肺类癌是一种罕见的神经内分泌肿瘤。肺类癌的分子特征尚未明确。微小 RNA（miRNA）是一种有效的基因表达调控因子，在癌症的发生和发展中具有重要作用。然而，miRNA 在肺类癌发病机制中的作用知之甚少。我们的目标是鉴定一种罕见的具有转移特征的典型肺类癌病例中常见的失调 miRNA，并绘制与疾病发展和进展相关的途径中的 miRNA 靶基因图谱。
采用 TaqMan 低密度阵列评估 miRNA 表达谱，该平台包括 384 个 miRNA。与参考正常肺组织相比，在肿瘤及其相应的淋巴结转移中生成 miRNA 图谱。此外，在另一个独立的公开外部数据集（n=19 例典型肺类癌；2/19 为转移性肿瘤，与 6 例正常肺组织相比，GSE77380）中验证了 miRNA 表达。在这项分析之后，应用计算工具进行数据解释。miRTarBase 用于确定 miRNA-靶基因，然后使用 ToppGene Suite 分析来识别途径和生物学功能。此外，在第二个独立的外部数据集（n=13 个肿瘤样本，GSE35679）中验证了 miRNA 靶基因的表达。在两个验证分析（miRNAs 和基因）中均使用 GEO2R 数据分析工具。
我们在肿瘤及其配对转移中发现了 15 个常见的显著下调 miRNA（倍数变化，FC≥2 和 p<0.05），在转移病灶中进一步降低。在外部数据集 GSE77380 中验证了 miR-126-3p 和 miR-146b-5p 的下调。此外，miR-126-3p 靶向的 SOX2 和 TCF4 基因在外部数据集 GSE35679 中的六个典型肺类癌亚集中一致过表达。途径分析表明，miRNA miR-126-3p 和 miR-146b-5p 的靶基因在调节适应性免疫反应中起作用。
我们的结果有助于鉴定典型肺类癌及其相应淋巴结转移中 miRNA 表达的变化。miR-126-3p 和 miR-146b-5p 的下调水平和靶基因的过表达可能在该原发性典型肺类癌进展为区域性转移中发挥作用。鉴定的 miRNA 和靶基因是在更大数量的病例中进行验证的潜在候选物。
