Colangelo T, Polcaro G, Ziccardi P, Pucci B, Muccillo L, Galgani M, Fucci A, Milone M R, Budillon A, Santopaolo M, Votino C, Pancione M, Piepoli A, Mazzoccoli G, Binaschi M, Bigioni M, Maggi C A, Fassan M, Laudanna C, Matarese G, Sabatino L, Colantuoni V
Department of Sciences and Technologies, University of Sannio, Benevento, Italy.
Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale-IRCCS, Mercogliano (AV), Italy.
Cell Death Dis. 2016 Feb 25;7(2):e2120. doi: 10.1038/cddis.2016.28.
Impairment of the immune response and aberrant expression of microRNAs are emerging hallmarks of tumour initiation/progression, in addition to driver gene mutations and epigenetic modifications. We performed a preliminary survey of independent adenoma and colorectal cancer (CRC) miRnoma data sets and, among the most dysregulated miRNAs, we selected miR-27a and disclosed that it is already upregulated in adenoma and further increases during the evolution to adenocarcinoma. To identify novel genes and pathways regulated by this miRNA, we employed a differential 2DE-DIGE proteome analysis. We showed that miR-27a modulates a group of proteins involved in MHC class I cell surface exposure and, mechanistically, demonstrated that calreticulin is a miR-27a direct target responsible for most downstream effects in epistasis experiments. In vitro miR-27a affected cell proliferation and angiogenesis; mouse xenografts of human CRC cell lines expressing different miR-27a levels confirmed the protein variations and recapitulated the cell growth and apoptosis effects. In vivo miR-27a inversely correlated with MHC class I molecules and calreticulin expression, CD8(+) T cells infiltration and cytotoxic activity (LAMP-1 exposure and perforin release). Tumours with high miR-27a, low calreticulin and CD8(+) T cells' infiltration were associated with distant metastasis and poor prognosis. Our data demonstrate that miR-27a acts as an oncomiRNA, represses MHC class I expression through calreticulin downregulation and affects tumour progression. These results may pave the way for better diagnosis, patient stratification and novel therapeutic approaches.
除驱动基因突变和表观遗传修饰外，免疫反应受损和微小RNA的异常表达正成为肿瘤发生/进展的新标志。我们对独立的腺瘤和结直肠癌（CRC）微小RNA数据集进行了初步调查，在失调最严重的微小RNA中，我们选择了miR-27a，并发现它在腺瘤中已经上调，在向腺癌演变过程中进一步增加。为了鉴定受该微小RNA调控的新基因和通路，我们采用了差异二维凝胶电泳-荧光差异凝胶电泳蛋白质组分析。我们表明，miR-27a调节一组参与MHC I类细胞表面暴露的蛋白质，并且在机制上证明钙网蛋白是miR-27a的直接靶点，在上位性实验中负责大多数下游效应。体外实验中，miR-27a影响细胞增殖和血管生成；表达不同miR-27a水平的人CRC细胞系的小鼠异种移植证实了蛋白质变化，并重现了细胞生长和凋亡效应。在体内，miR-27a与MHC I类分子和钙网蛋白表达、CD8(+) T细胞浸润及细胞毒性活性（LAMP-1暴露和穿孔素释放）呈负相关。具有高miR-27a、低钙网蛋白和CD8(+) T细胞浸润的肿瘤与远处转移和不良预后相关。我们的数据表明，miR-27a作为一种癌基因微小RNA，通过下调钙网蛋白抑制MHC I类表达并影响肿瘤进展。这些结果可能为更好的诊断、患者分层和新的治疗方法铺平道路。
