Mitomo Shingo, Maesawa Chihaya, Ogasawara Satoshi, Iwaya Takeshi, Shibazaki Masahiko, Yashima-Abo Akiko, Kotani Koji, Oikawa Hiroki, Sakurai Eiich, Izutsu Naoko, Kato Kuniyuki, Komatsu Hideaki, Ikeda Kenichro, Wakabayashi Go, Masuda Tomoyuki
Department of Pathology, School of Medicine, Iwate Medical University, Morioka 020-8505, Japan.
Cancer Sci. 2008 Feb;99(2):280-6. doi: 10.1111/j.1349-7006.2007.00666.x. Epub 2008 Jan 14.
Alterations of several microRNA (miRNA) have been linked to cancer development and its biology. To search for unique miRNA that might play a role in the development of anaplastic thyroid carcinoma (ATC), we examined the expression of multiple miRNA and their functional effects on target genes in human thyroid carcinoma cell lines. We quantitatively evaluated the expression of multiple miRNA in 10 ATC and five papillary thyroid carcinoma (PTC) cell lines, as well as primary tumors from 11 thyroid carcinoma patients (three ATC and eight PTC), using the stem-loop-mediated reverse transcription real-time polymerase chain reaction method. We also examined the target gene specificity of unique miRNA that showed differences in expression between ATC and PTC cell lines. One miRNA, miR-138, was significantly downregulated in ATC cell lines in comparison with PTC (P < 0.01). Eleven miRNA (including miR-138) potentially targeting the human telomerase reverse transcriptase (hTERT) gene were totally downregulated in both ATC and PTC cell lines in comparison with normal thyroid tissues. A tendency for an inverse correlation between miR-138 and hTERT protein expression was observed in the thyroid cancer cell lines, although this failed to reach significance (r = -0.392, P = 0.148). We demonstrated that overexpression of miR-138 induced a reduction in hTERT protein expression, and confirmed target specificity between miR-138 and the hTERT 3'-untranslated region by luciferase reporter assay. These results suggest that loss of miR-138 expression may partially contribute to the gain of hTERT protein expression in ATC, and that further multiple miRNA targeting hTERT mRNA might be involved in the development of thyroid carcinoma.
多种微小RNA（miRNA）的改变与癌症的发生发展及其生物学特性相关。为了寻找可能在间变性甲状腺癌（ATC）发生发展中起作用的独特miRNA，我们检测了多种miRNA在人甲状腺癌细胞系中的表达及其对靶基因的功能影响。我们采用茎环介导的逆转录实时聚合酶链反应方法，定量评估了10株ATC细胞系和5株甲状腺乳头状癌（PTC）细胞系以及11例甲状腺癌患者（3例ATC和8例PTC）原发肿瘤中多种miRNA的表达。我们还检测了在ATC和PTC细胞系中表达存在差异的独特miRNA的靶基因特异性。与PTC相比，一种miRNA，即miR - 138，在ATC细胞系中显著下调（P < 0.01）。与正常甲状腺组织相比，11种可能靶向人端粒酶逆转录酶（hTERT）基因的miRNA（包括miR - 138）在ATC和PTC细胞系中均完全下调。在甲状腺癌细胞系中观察到miR - 138与hTERT蛋白表达呈负相关趋势，尽管未达到显著水平（r = -0.392，P = 0.148）。我们证明miR - 138的过表达导致hTERT蛋白表达降低，并通过荧光素酶报告基因检测证实了miR - 138与hTERT 3'非翻译区之间的靶标特异性。这些结果表明，miR - 138表达缺失可能部分导致ATC中hTERT蛋白表达增加，并且进一步靶向hTERT mRNA的多种miRNA可能参与甲状腺癌的发生发展。
