Takakura Shu, Mitsutake Norisato, Nakashima Masahiro, Namba Hiroyuki, Saenko Vladimir A, Rogounovitch Tatiana I, Nakazawa Yuka, Hayashi Tomayoshi, Ohtsuru Akira, Yamashita Shunichi
Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
Cancer Sci. 2008 Jun;99(6):1147-54. doi: 10.1111/j.1349-7006.2008.00800.x. Epub 2008 Apr 21.
Micro RNAs (miRNAs) are non-coding small RNAs and constitute a novel class of negative gene regulators that are found in both plants and animals. Several miRNAs play crucial roles in cancer cell growth. To identify miRNAs specifically deregulated in anaplastic thyroid cancer (ATC) cells, we performed a comprehensive analysis of miRNA expressions in ARO cells and primary thyrocytes using miRNA microarrays. MiRNAs in a miR-17-92 cluster were overexpressed in ARO cells. We confirmed the overexpression of those miRNAs by Northern blot analysis in ARO and FRO cells. In 3 of 6 clinical ATC samples, miR-17-3p and miR-17-5p were robustly overexpressed in cancer lesions compared to adjacent normal tissue. To investigate the functional role of these miRNAs in ATC cells, ARO and FRO cells were transfected with miRNA inhibitors, antisense oligonucleotides containing locked nucleic acids. Suppression of miR-17-3p caused complete growth arrest, presumably due to caspase activation resulting in apoptosis. MiR-17-5p or miR-19a inhibitor also induced strong growth reduction, but only miR-17-5p inhibitor led to cellular senescence. On the other hand, miR-18a inhibitor only moderately attenuated the cell growth. Thus, we have clarified functional differences among the members of the cluster in ATC cells. In conclusion, these findings suggest that the miR-17-92 cluster plays an important role in certain types of ATCs and could be a novel target for ATC treatment.
微小RNA（miRNA）是一类非编码小RNA，构成了动植物中发现的新型负性基因调节因子。几种miRNA在癌细胞生长中发挥关键作用。为了鉴定在间变性甲状腺癌（ATC）细胞中特异性失调的miRNA，我们使用miRNA微阵列对ARO细胞和原代甲状腺细胞中的miRNA表达进行了全面分析。miR-17-92簇中的miRNA在ARO细胞中过表达。我们通过Northern印迹分析在ARO和FRO细胞中证实了这些miRNA的过表达。在6例临床ATC样本中的3例中，与相邻正常组织相比，癌灶中miR-17-3p和miR-17-5p强烈过表达。为了研究这些miRNA在ATC细胞中的功能作用，用miRNA抑制剂（含锁核酸的反义寡核苷酸）转染ARO和FRO细胞。抑制miR-17-3p导致完全生长停滞，可能是由于半胱天冬酶激活导致细胞凋亡。miR-17-5p或miR-19a抑制剂也诱导强烈的生长抑制，但只有miR-17-5p抑制剂导致细胞衰老。另一方面，miR-18a抑制剂仅适度减弱细胞生长。因此，我们阐明了该簇成员在ATC细胞中的功能差异。总之，这些发现表明miR-17-92簇在某些类型的ATC中起重要作用，并且可能是ATC治疗的新靶点。
