Cellular and Molecular Research and Division of Medical Oncology, National Cancer Centre of Singapore, Singapore.
Clin Cancer Res. 2011 May 1;17(9):2657-67. doi: 10.1158/1078-0432.CCR-10-3152. Epub 2011 Mar 17.
MicroRNAs (miRNA) play pivotal oncogenic and tumor-suppressor roles in several human cancers. We sought to discover novel tumor-suppressor miRNAs in gastric cancer (GC).
Using Agilent miRNA microarrays, we compared miRNA expression profiles of 40 primary gastric tumors and 40 gastric normal tissues, identifying miRNAs significantly downregulated in gastric tumors.
Among the top 80 miRNAs differentially expressed between gastric tumors and normals (false discovery rate < 0.01), we identified hsa-miR-486 (miR-486) as a significantly downregulated miRNA in primary GCs and GC cell lines. Restoration of miR-486 expression in GC cell lines (YCC3, SCH and AGS) caused suppression of several pro-oncogenic traits, whereas conversely inhibiting miR-486 expression in YCC6 GC cells enhanced cellular proliferation. Array-CGH analysis of 106 primary GCs revealed genomic loss of the miR-486 locus in approximately 25% to 30% of GCs, including two tumors with focal genomic losses specifically deleting miR-486, consistent with miR-486 playing a tumor-suppressive role. Bioinformatic analysis identified the secreted antiapoptotic glycoprotein OLFM4 as a potential miR-486 target. Restoring miR-486 expression in GC cells decreased endogenous OLFM4 transcript and protein levels, and also inhibited expression of luciferase reporters containing an OLFM4 3' untranslated region with predicted miR-486 binding sites. Supporting the biological relevance of OLFM4 as a miR-486 target, proliferation in GC cells was also significantly reduced by OLFM4 silencing.
miR-486 may function as a novel tumor-suppressor miRNA in GC. Its antioncogenic activity may involve the direct targeting and inhibition of OLFM4.
微小 RNA（miRNA）在几种人类癌症中发挥关键致癌和肿瘤抑制作用。我们试图在胃癌（GC）中发现新的肿瘤抑制 miRNA。
使用 Agilent miRNA 微阵列，我们比较了 40 例原发性胃癌和 40 例胃正常组织的 miRNA 表达谱，确定了在胃肿瘤中显著下调的 miRNA。
在胃癌和正常组织之间差异表达的前 80 个 miRNA 中（错误发现率<0.01），我们鉴定出 hsa-miR-486（miR-486）为原发性 GC 和 GC 细胞系中显著下调的 miRNA。在 GC 细胞系（YCC3、SCH 和 AGS）中恢复 miR-486 的表达导致抑制了几个促癌特性，而相反地在 YCC6 GC 细胞中抑制 miR-486 的表达增强了细胞增殖。对 106 例原发性 GC 的 array-CGH 分析显示，miR-486 基因座的基因组缺失约占 GC 的 25%至 30%，包括两个肿瘤具有特异性缺失 miR-486 的局灶性基因组缺失，与 miR-486 发挥肿瘤抑制作用一致。生物信息学分析鉴定出分泌的抗凋亡糖蛋白 OLFM4 为潜在的 miR-486 靶标。在 GC 细胞中恢复 miR-486 的表达降低了内源性 OLFM4 转录本和蛋白水平，并抑制了包含预测 miR-486 结合位点的 OLFM4 3'非翻译区的荧光素酶报告基因的表达。支持 OLFM4 作为 miR-486 靶标的生物学相关性，GC 细胞的增殖也因 OLFM4 的沉默而显著降低。
miR-486 可能在 GC 中作为一种新的肿瘤抑制 miRNA 发挥作用。其抗癌活性可能涉及对 OLFM4 的直接靶向和抑制。
