恶性与交界性胃肠道间质瘤差异表达microRNA的初步筛选

Screening of differentially expressed microRNAs in borderline and malignant gastrointestinal stromal tumors

目的胃肠道间质瘤（GIST）包括良性、交界性及高度恶性的广谱生物学行为，通过初步筛选恶性GIST与交界性GIST差异表达的microRNA（miRNA），探讨miRNA在GIST恶性转化过程中的潜在作用。方法收集6例胃GIST标本，恶性组3例，交界组3例。用Agilent人miRNA寡核苷酸基因芯片V3（955个已知的miRNA）进行检测。选取恶性组与交界组之间4个差异表达最明显的miRNA，利用荧光即时定量PCR技术，在22个样本中进行验证。结果恶性组与交界组相比较，相差倍数2倍以上且P值小于0．05的差异表达miRNA有14个，上调的有5个，下调的有9个。其中差异最明显，即P值最小的4个miRNA，分别为miR-221、miR-135b、miR-675＊、miR-218，前两者在恶性组中上调，后两者下调。荧光即时定量PCR在22个样本中验证显示，miR．221和miR-675＊的差异倍数与基因芯片的结果基本相符。结论通过miRNA芯片初步筛选和荧光即时定量PCR验证，显示miR-221和miR-675＊在恶性和交界性GIST中的表达有差异性，提示两者可能与GIST的恶性转化有关，在GIST的生物学行为判断上有潜在的应用价值。

Objective Gastrointestinal stromal tumors （GISTs） have a broad spectrum of biological behaviors ranging from benign, borderline and malignant. This study aimed to screen differentially expressed microRNAs （miRNAs） between malignant and borderline GISTs and to investigate the potential role of miRNAs in the malignant transformation of GISTs. Methods Six GIST samples ineluding borderline tumors （n = 3 ） and malignant tumors （n = 3 ） were collected based on the clinical and pathological characteristics. Total RNA was extracted, followed by miRNA microarray analysis to screen the differentially expressed miRNAs. The most significantly expressed 4 miRNAs were then chosen for further validation by real-time PCR in 22 additional GIST samples. Results Direct comparison of malignant group versus borderline group revealed 14 significantly and differentially expressed miRNAs （P 〈 0. 05, with a fold change of 〈 0. 5 or 〉 2）. Five miRNAs were up-regulated and nine were down-regulated in the malignant group. Four miRNAs （miR-221, miR-135b, miR-675＊ and miR-218） were most siguifieantly and differentially expressed between the two groups. The differential expression of 2 miRNAs （miR-221 and miR-675 ＊ ） were subsequently confirmed with good concordance by real-time PCR. Conclusions The differential miRNA expression profiles between two groups are revealed by miRNA mieroarray assay, and confirmed by real-time PCR. Among differentially expressed miRNAs, miR-221 and miR-675 ＊ might be related to the malignant transformation of GISTs. and have a potential value in predicting biological behavior of CISTs.