Down-regulation of the miR-25 and miR-30d contributes to the development of anaplastic thyroid carcinoma targeting the polycomb protein EZH2.

CONTEXT We have previously demonstrated that a set of micro-RNA (miRNA) is significantly down-regulated in anaplastic thyroid carcinomas with respect to normal thyroid tissues and to differentiated thyroid carcinomas. OBJECTIVE The objective was to evaluate the role of two of these down-regulated miRNA, miR-25 and miR-30d, in thyroid carcinogenesis. DESIGN miR-25 and miR-30d expression was restored in the ACT-1, 8505c, and FRO anaplastic thyroid cell lines, and their effects on cell proliferation, migration, and target expression were evaluated. RESULTS We report that miR-25 and miR-30d target the polycomb protein enhancer of zeste 2 (EZH2) that has oncogenic activity and is drastically up-regulated in anaplastic thyroid carcinomas but not in the differentiated ones. Ectopic expression of miR-25 and miR-30d inhibited proliferation and colony formation of anaplastic thyroid carcinoma cells by inducing G2/M-phase cell-cycle arrest. Finally, we found an inverse correlation between the expression of these miRNA and the EZH2 protein levels in anaplastic thyroid carcinomas, suggesting a critical role of these miRNA in regulating EZH2 expression also in vivo. CONCLUSION The down-regulation of miR-25 and miR-30d could contribute to the process of thyroid cancer progression, leading to the development of anaplastic carcinomas targeting EZH2 mRNA.

[1]  Yang Li,et al.  Role of the miR‐106b‐25 microRNA cluster in hepatocellular carcinoma , 2009, Cancer science.

[2]  J. Fagin,et al.  High prevalence of mutations of the p53 gene in poorly differentiated human thyroid carcinomas. , 1993, The Journal of clinical investigation.

[3]  D. Zelterman,et al.  Downregulation of p27KIP1 and Ki67/Mib1 labeling index support the classification of thyroid carcinoma into prognostically relevant categories. , 1999, The American journal of surgical pathology.

[4]  V. Orlando,et al.  Enhancer of zeste homolog 2 overexpression has a role in the development of anaplastic thyroid carcinomas. , 2011, The Journal of clinical endocrinology and metabolism.

[5]  Haojie Huang,et al.  Androgens suppress EZH2 expression via retinoblastoma (RB) and p130-dependent pathways: a potential mechanism of androgen-refractory progression of prostate cancer. , 2010, Endocrinology.

[6]  S. Dhanasekaran,et al.  The polycomb group protein EZH2 is involved in progression of prostate cancer , 2002, Nature.

[7]  Kristian Helin,et al.  EZH2 is downstream of the pRB‐E2F pathway, essential for proliferation and amplified in cancer , 2003, The EMBO journal.

[8]  D. Wynford‐Thomas,et al.  Detection of theH-RAS oncogene in human thyroid anaplastic carcinomas , 1989, Experientia.

[9]  Tao Jiang,et al.  The role of microRNA in human lung squamous cell carcinoma. , 2010, Cancer genetics and cytogenetics.

[10]  Kristian Helin,et al.  Polycomb group proteins: navigators of lineage pathways led astray in cancer , 2009, Nature Reviews Cancer.

[11]  V. Pirrotta,et al.  Related chromosome binding sites for zeste, suppressors of zeste and Polycomb group proteins in Drosophila and their dependence on Enhancer of zeste function. , 1993, The EMBO journal.

[12]  M. Loda,et al.  Identification of the miR-106b~25 MicroRNA Cluster as a Proto-Oncogenic PTEN-Targeting Intron That Cooperates with Its Host Gene MCM7 in Transformation , 2010, Science Signaling.

[13]  Anton J. Enright,et al.  Human MicroRNA Targets , 2004, PLoS biology.

[14]  R. Kingston,et al.  The Core of the Polycomb Repressive Complex Is Compositionally and Functionally Conserved in Flies and Humans , 2002, Molecular and Cellular Biology.

[15]  P. Chieffi,et al.  High-mobility group A1 proteins regulate p53-mediated transcription of Bcl-2 gene. , 2010, Cancer research.

[16]  C. Larsson,et al.  Array-CGH identifies cyclin D1 and UBCH10 amplicons in anaplastic thyroid carcinoma. , 2008, Endocrine-related cancer.

[17]  D. Rimm,et al.  β-Catenin Dysregulation in Thyroid Neoplasms : Down-Regulation, Aberrant Nuclear Expression, and CTNNB1 Exon 3 Mutations Are Markers for Aggressive Tumor Phenotypes and Poor Prognosis , 2001 .

[18]  C. Croce,et al.  A microRNA expression signature of human solid tumors defines cancer gene targets , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[19]  Ashish Rajput,et al.  Anaplastic Thyroid Carcinoma: Expression Profile of Targets for Therapy Offers New Insights for Disease Treatment , 2007, Annals of Surgical Oncology.

[20]  A. Hatzigeorgiou,et al.  A combined computational-experimental approach predicts human microRNA targets. , 2004, Genes & development.

[21]  C. Burge,et al.  Prediction of Mammalian MicroRNA Targets , 2003, Cell.

[22]  S. Varambally,et al.  Genomic Loss of microRNA-101 Leads to Overexpression of Histone Methyltransferase EZH2 in Cancer , 2008, Science.

[23]  Rameen Beroukhim,et al.  An oncogene–tumor suppressor cascade drives metastatic prostate cancer by coordinately activating Ras and nuclear factor-κB , 2010, Nature Medicine.

[24]  Debashis Ghosh,et al.  EZH2 is a marker of aggressive breast cancer and promotes neoplastic transformation of breast epithelial cells , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[25]  V. Rotter,et al.  Activated p53 suppresses the histone methyltransferase EZH2 gene , 2004, Oncogene.

[26]  Ming Yao,et al.  MicroRNA‐30d promotes tumor invasion and metastasis by targeting Galphai2 in hepatocellular carcinoma , 2010, Hepatology.

[27]  A. El‐Naggar,et al.  Phosphatidylinositol 3-kinase/akt and ras/raf-mitogen-activated protein kinase pathway mutations in anaplastic thyroid cancer. , 2008, The Journal of clinical endocrinology and metabolism.

[28]  M. Pierotti,et al.  Gene p53 mutations are restricted to poorly differentiated and undifferentiated carcinomas of the thyroid gland. , 1993, The Journal of clinical investigation.

[29]  C. Croce,et al.  MicroRNA signatures in human cancers , 2006, Nature Reviews Cancer.

[30]  C. Croce,et al.  Specific microRNAs are downregulated in human thyroid anaplastic carcinomas , 2007, Oncogene.

[31]  Michael H Handler,et al.  Survey of MicroRNA expression in pediatric brain tumors , 2011, Pediatric blood & cancer.

[32]  G. Brabant,et al.  Wnt/β-Catenin Signaling Mediates Antineoplastic Effects of Imatinib Mesylate (Gleevec) in Anaplastic Thyroid Cancer , 2006 .

[33]  A. de Leiva,et al.  Ras Oncogene Mutations in Thyroid Tumors: Polymerase Chain Reaction‐Restriction‐Fragment‐Length Polymorphism Analysis from Paraffin‐Embedded Tissues , 1996, Diagnostic molecular pathology : the American journal of surgical pathology, part B.