Functional Genomics Core Facility, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Istituto Nazionale dei Tumori, Milan, Italy.
PLoS One. 2013;8(3):e58849. doi: 10.1371/journal.pone.0058849. Epub 2013 Mar 6.
We recently reported that peritumoral CpG-ODN treatment, activating TLR-9 expressing cells in tumor microenvironment, induces modulation of genes involved in DNA repair and sensitizes cancer cells to DNA-damaging cisplatin treatment. Here, we investigated whether this treatment induces modulation of miRNAs in tumor cells and their relevance to chemotherapy response. Array analysis identified 20 differentially expressed miRNAs in human IGROV-1 ovarian tumor cells from CpG-ODN-treated mice versus controls (16 down- and 4 up-regulated). Evaluation of the role of the 3 most differentially expressed miRNAs on sensitivity to cisplatin of IGROV-1 cells revealed significantly increased cisplatin cytotoxicity upon ectopic expression of hsa-miR-302b (up-modulated in our array), but no increased effect upon reduced expression of hsa-miR-424 or hsa-miR-340 (down-modulated in our array). Accordingly, hsa-miR-302b expression was significantly associated with time to relapse or overall survival in two data sets of platinum-treated ovarian cancer patients. Use of bio-informatics tools identified 19 mRNAs potentially targeted by hsa-miR-302b, including HDAC4 gene, which has been reported to mediate cisplatin sensitivity in ovarian cancer. Both HDAC4 mRNA and protein levels were significantly reduced in IGROV-1 cells overexpressing hsa-miR-302b. Altogether, these findings indicate that hsa-miR-302b acts as a "chemosensitizer" in human ovarian carcinoma cells and may represent a biomarker able to predict response to cisplatin treatment. Moreover, the identification of miRNAs that improve sensitivity to chemotherapy provides the experimental underpinning for their possible future clinical use.
我们最近报道，肿瘤周围 CpG-ODN 治疗通过激活肿瘤微环境中表达 TLR-9 的细胞，诱导参与 DNA 修复的基因的调节，并使癌细胞对 DNA 损伤的顺铂治疗敏感。在这里，我们研究了这种治疗是否会诱导肿瘤细胞中 miRNA 的调节及其与化疗反应的相关性。阵列分析确定了来自 CpG-ODN 处理的小鼠与对照的人类 IGROV-1 卵巢肿瘤细胞中 20 个差异表达的 miRNA（16 个下调和 4 个上调）。评估这 3 个差异表达最多的 miRNA 对 IGROV-1 细胞对顺铂敏感性的作用表明，hsa-miR-302b（在我们的阵列中上调）的异位表达显著增加了顺铂的细胞毒性，但 hsa-miR-424 或 hsa-miR-340 的表达降低（在我们的阵列中下调）没有增加作用。相应地，hsa-miR-302b 的表达与两个铂类治疗的卵巢癌患者数据集的复发时间或总生存时间显著相关。生物信息学工具的使用鉴定了 19 个可能被 hsa-miR-302b 靶向的 mRNA，包括已报道在卵巢癌中介导顺铂敏感性的 HDAC4 基因。在过表达 hsa-miR-302b 的 IGROV-1 细胞中，HDAC4 mRNA 和蛋白水平均显著降低。总之，这些发现表明 hsa-miR-302b 作为人类卵巢癌细胞中的“化疗增敏剂”起作用，并且可能代表能够预测对顺铂治疗反应的生物标志物。此外，鉴定能够提高对化疗敏感性的 miRNA 为它们未来可能的临床应用提供了实验基础。
