Comprehensive analysis of circulating microRNAs in plasma of patients with pituitary adenomas

Background: Circulating miRNAs in pituitary adenoma would help patient care especially in non-functioning adenoma cases as minimally invasive biomarkers of tumor recurrence and progression. Aim: Our aim was to investigate plasma miRNA profile in patients with pituitary adenoma. Materials and Methods: 149 plasma and extracellular vesicle (preoperative, early- and late postoperative) samples were collected from 45 pituitary adenoma patients. Adenomas were characterized based on anterior pituitary hormones and transcription factors by immunostaining. MiRNA next generation sequencing was performed on 36 samples (discovery set). Individual TaqMan assay was used for validation on extended sample set. PA tissue miRNAs were evaluated by TaqMan array and literature data. Results: Global downregulation of miRNA expression was observed in plasma samples of pituitary adenoma patients compared to normal samples. Expression of 29 miRNAs and isomiR variants were able to distinguish preoperative plasma samples and normal controls. MiRNAs with altered expression in both plasma and different adenoma tissues were identified. 3, 7 and 66 miRNAs expressed differentially between preoperative and postoperative plasma samples in growth hormone secreting, FSH/LH+ and hormone-immunonegative groups, respectively. MiR-143-3p was downregulated in late- but not in early postoperative plasma samples compared to preoperative ones exclusively in FSH/LH+ adenomas. Plasma level of miR-143-3p discriminated these samples with 81.8% sensitivity and 72.3% specificity (AUC=0.79; p=0.02). Conclusions: Differentially expressed miRNAs in pituitary adenoma tissues have low abundance in plasma minimizing their role as biomarkers. Plasma miR-143-3p decreases in patients with FSH/LH+ adenoma indicated successful surgery, but its application for evaluating tumor recurrence needs further investigation. Overall design: Altogether 38 plasma samples were analysed by high-throughput miRNA expression profiling. 36 samples were obtained from 18 pituitary adenoma patients before and after pituitary adenoma removal, and 2 samples were derived from healthy volunteers without any known disease.

研究背景：垂体腺瘤患者外周循环中的微小RNA（miRNA）可作为肿瘤复发与进展的微创生物标志物，尤其能为无功能腺瘤患者的临床诊疗提供有力支持。研究目的：本研究旨在探究垂体腺瘤患者的血浆miRNA表达谱。材料与方法：本研究从45例垂体腺瘤患者体内采集了149份血浆及细胞外囊泡（extracellular vesicle）样本，样本涵盖术前、术后早期及术后晚期三个时间节点。通过免疫染色法，基于垂体前叶激素与转录因子对腺瘤进行分型。对36份样本（发现集）开展miRNA二代测序；采用TaqMan单重检测法对扩大样本集进行验证。通过TaqMan芯片阵列与公开文献数据，对垂体腺瘤组织中的miRNA进行分析评估。研究结果：与正常对照样本相比，垂体腺瘤患者的血浆样本中出现了miRNA表达的整体下调。29种miRNA及其同型异构体变异体（isomiR variants）的表达水平可有效区分术前血浆样本与正常对照。本研究还鉴定出在血浆与不同腺瘤组织中均存在表达异常的miRNA。在生长激素分泌型、促卵泡激素/黄体生成素阳性（FSH/LH+）以及激素免疫阴性型垂体腺瘤患者中，分别有3种、7种及66种miRNA在术前与术后血浆样本间存在差异表达。仅在FSH/LH+型腺瘤中，相较于术前样本，miR-143-3p在术后晚期血浆样本中呈下调状态，而在术后早期血浆样本中无此变化。血浆miR-143-3p水平对该类样本的区分效能为：灵敏度81.8%，特异度72.3%（受试者工作特征曲线下面积（Area Under the Receiver Operating Characteristic Curve，AUC）=0.79；p=0.02）。研究结论：垂体腺瘤组织中差异表达的miRNA在血浆中丰度较低，这限制了其作为生物标志物的应用价值。FSH/LH+型腺瘤患者的血浆miR-143-3p水平随手术成功实施而降低，但该分子用于评估肿瘤复发的临床应用仍需进一步研究。整体实验设计：本研究通过高通量miRNA表达谱分析共检测了38份血浆样本，其中36份来自18例垂体腺瘤患者的术前及术后肿瘤切除样本，剩余2份取自无已知疾病史的健康志愿者。