Abstract 3013: Differential approach to define microRNA expression patterns in osteosarcomas
Authors: Montanini Luisa , Pazzaglia Laura , Spessotto Paola , Kjems Jørgen , Conti Amalia , Perris Roberto , den Boer Monique L. , Benassi Maria Serena 
Published: February 2011

Many molecules have been described as involved in the migration process but in this last year many investigations pointed out that in addition to alteration in protein encoding genes, abnormalities in non coding genes could contribute to carcinogenesis.

As a first step in the effort to choose the most suitable cell lines to approach the metastasis process, the cell kinetics of different sarcoma cell lines was detected. Some differences in cell migration capability were clearly evident. In particular, three osteosarcoma cell lines 143B, MG-63 and Saos-2 showed a different migration behavior with respect to other sarcoma cell lines.

Specific microRNA libraries were constructed using TopoTA cloning system supported by 5’ and 3’ adaptors beginning from total RNA of 143B and MG-63. Differentially expressed microRNA were identified. Many of these are important molecules already known in cancer. Furthermore an unknown sequence was found expressed in MG-63 cell line. This putative microRNA which localizes on the short art of human chromosome 7 was called miR-7 new. A structural analysis of pre-miRNA, shows harping stability and phylogenetic analysis through databases revealed sequence conservation.

Among different microRNAs belonging to 17-92 cluster, a known oncogenic family less investigated in sarcoma, the role of miR-93 was determined. Firstly miR-93 expression was evaluated on healthy human tissues. Some differences were found with a higher expression in frontal and occipital cortex and in bone marrow. Moreover, because of its importance in different tumour types miR-93 expression was investigated in various sarcomas cell lines in comparison with mesenchymal cells. To better understand the importance and role of miR-93 in the cell, MG-63 and 143B cell lines were transducted by using a plasmid containing this miRNA.

The two clones obtained with miR-93 higher expression, were analysed by using wound healing migration experiments. It was observed that over-expression of miR-93 in clones seems to reduce cell movement when compared both to the wild types and control vector.

Simultaneously, MG-63, 143B, U2-OS cell lines were analyzed by using high-throughput technique to determine potential miRNAs involvment in osteosarcoma tumors.

miR-484, miR-196a, miR-9 and miR-183, over-expressed in all cell lines, were analyzed in 23 osteosarcoma samples (10 low grade and 13 high grade) and normal tissue by Real Time PCR analysis.

In contrast to cell lines results, under-expression of these microRNAs in sarcoma compared to normal tissue were shown although in high grade samples an over-expression of miR-484 and miR-196a in comparison with low grade sarcomas was found. These results are in accordance with previous data reported in literature that describe miR-196a with oncogenic potential because its high expression promotes cell proliferation, cancer cell detachment, migration and invasion.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3013.