Rapti Stamatia-Maria, Kontos Christos K, Christodoulou Spyridon, Papadopoulos Iordanis N, Scorilas Andreas
Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Athens GR-15701, Greece.
Fourth Surgery Department, National and Kapodistrian University of Athens, University General Hospital "Attikon", Athens GR-12462, Greece.
Clin Biochem. 2017 Nov;50(16-17):918-924. doi: 10.1016/j.clinbiochem.2017.06.004. Epub 2017 Jun 15.
MicroRNA-34a (miR-34a) is regulated by TP53 and, in response, downregulates the expression of a gamut of protein-coding genes, including apoptosis regulators, transcription factors, cyclins, and cyclin-dependent kinases. Its upregulation initiates a reprogramming of gene expression and promotes apoptosis. The purpose of this study was the investigation of the potential clinical significance of miR-34a as a molecular prognostic biomarker in colorectal adenocarcinoma using an in-house real-time quantitative PCR (qPCR) methodology.
Total RNA was extracted from 113 primary colorectal adenocarcinoma specimens and 61 paired non-cancerous colorectal tissue samples. After polyadenylation and reverse transcription, miR-34a molecules were determined using qPCR based on SYBR Green chemistry. Calculations were performed using the comparative C method. Finally, extensive biostatistical analysis was performed.
miR-34a expression does not significantly differ between colorectal adenocarcinoma tissue specimens and adjacent non-cancerous mucosae. However, miR-34a expression increases progressively as colorectal adenocarcinoma loses its differentiation, being highest in grade III tumors (P=0.010). Moreover, miR-34a expression is a potential unfavorable prognostic biomarker in colorectal adenocarcinoma, predicting poor disease-free and overall survival (P=0.002 and P=0.019, respectively), independently of classical clinicopathological parameters. Most importantly, miR-34a expression stratifies patients without local (N0) and/or distant metastasis (M0) at the time of diagnosis into two groups with substantially different prognosis (P=0.013 and P=0.002, respectively).
High miR-34a levels in colorectal adenocarcinoma predict a rather increased risk for disease recurrence and poor overall survival, particularly in patients at an early TNM stage. The unfavorable prognostic potential of miR-34a expression is independent of established prognostic features of colorectal adenocarcinoma.
微小RNA-34a（miR-34a）受TP53调控，作为响应，它会下调一系列蛋白质编码基因的表达，这些基因包括凋亡调节因子、转录因子、细胞周期蛋白和细胞周期蛋白依赖性激酶。其上调会引发基因表达重编程并促进细胞凋亡。本研究的目的是使用内部实时定量聚合酶链反应（qPCR）方法，研究miR-34a作为结直肠癌分子预后生物标志物的潜在临床意义。
从113例原发性结直肠癌标本和61对配对的非癌性结直肠组织样本中提取总RNA。在进行多聚腺苷酸化和逆转录后，基于SYBR Green化学法使用qPCR测定miR-34a分子。使用比较C法进行计算。最后，进行了广泛的生物统计学分析。
结直肠癌组织标本与相邻非癌性黏膜之间的miR-34a表达无显著差异。然而，随着结直肠癌分化程度降低，miR-34a表达逐渐增加，在III级肿瘤中最高（P=0.010）。此外，miR-34a表达是结直肠癌中一种潜在的不良预后生物标志物，可预测无病生存期和总生存期较差（分别为P=0.002和P=0.019），且独立于经典的临床病理参数。最重要的是，miR-34a表达将诊断时无局部（N0）和/或远处转移（M0）的患者分为两组，其预后有显著差异（分别为P=0.013和P=0.002）。
结直肠癌中miR-34a水平高预示疾病复发风险增加和总生存期较差，尤其是在TNM早期阶段的患者中。miR-34a表达的不良预后潜力独立于结直肠癌已确立的预后特征。
