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| Author(s): |
Cesar Seigi Fuziwara
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2010-08-24 |
| Examining board members: |
Edna Teruko Kimura;
Maria Luiza Morais Barreto de Chaves;
Ileana Gabriela Sanchez de Rubio
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| Advisor: | Edna Teruko Kimura |
| Abstract | |
In cancer, alteration in microRNA, small RNAs (~22nt) that regulate post-transcriptionally protein levels, exerts oncogenic role (oncomiR). OncomiRs control genes involved in cell proliferation and apoptosis, influencing cancer biology. Papillary thyroid cancer displays activating genetic alterations in MAPK signaling pathway (RET>RAS>BRAF>ERK). Using conditional induction of oncogenes in thyroid cells, we observed that RET/PTC decreases let-7 miRNA expression. In papillary thyroid cancer cell TPC-1 (with RET/PTC-1) we observed that let-7 introduction inhibits cell proliferation and ERK phosphorylation, indicating tumor suppressor role for let-7. In anaplastic thyroid cancer, we evaluate the role of introduction of miR-17-92 cluster in ARO cell line. We observed in vitro that miR-17-92 increases ARO cell proliferation and viability, acting as oncogene. However, these cells show impaired soft agar growth. In xenotransplant, ARO-miR-17-92 tumors are smaller in volume and express reduced levels of MMP-9, indicating a tumor suppressor role for the cluster. (AU) | |