Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer.
Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer.
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DOI：
10.1038/cddis.2016.28
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发表时间：
2016-02-25
影响因子：
9
通讯作者：
Colantuoni V
中科院分区：
文献类型：
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作者：
Colangelo T;Polcaro G;Ziccardi P;Pucci B;Muccillo L;Galgani M;Fucci A;Milone MR;Budillon A;Santopaolo M;Votino C;Pancione M;Piepoli A;Mazzoccoli G;Binaschi M;Bigioni M;Maggi CA;Fassan M;Laudanna C;Matarese G;Sabatino L;Colantuoni V
除了驱动基因突变和表观遗传修饰之外，免疫应答受损和microRNA的异常表达是肿瘤起始/进展的新标志。我们对独立的腺瘤和结直肠癌（CRC）miRnoma数据集进行了初步调查，在调节最失调的miRns中，我们选择了miR-27 a，并发现它已经在腺瘤中上调，并在演变为腺癌期间进一步增加。为了鉴定这种miRNA调控的新基因和途径，我们采用了差异2DE-DIGE蛋白质组分析。我们发现miR-27 a调节一组参与MHC I类细胞表面暴露的蛋白质，并且从机制上证明钙网蛋白是负责上位性实验中大多数下游效应的miR-27 a直接靶点。体外miR-27 a影响细胞增殖和血管生成;表达不同miR-27 a水平的人CRC细胞系的小鼠异种移植物证实了蛋白质变异，并重现了细胞生长和凋亡效应。体内miR-27 a与MHC I类分子和钙网蛋白表达、CD 8 + T细胞浸润和细胞毒性活性（LAMP-1暴露和穿孔素释放）呈负相关。高miR-27 a、低钙网蛋白和CD 8 + T细胞浸润的肿瘤与远处转移和预后不良相关。我们的数据表明，miR-27 a作为一种oncomiRNA，通过钙网蛋白下调抑制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。
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.