Characterization of human multicentric osteosarcoma using newly established cells derived from multicentric osteosarcoma.

PURPOSE: Human multicentric osteosarcoma (HMOS) is a rare, aggressive variant of osteosarcoma, and its etiology is not clear. We used newly established HMOS cells, which were derived from primary (HMOS-A) and secondary (HMOS-P) lesions, respectively, to perform a basic study analyzing the cellular biology and gene expression of HMOS. METHODS: We performed a cell growth assay, an invasion assay, DNA microarray analysis, quantitative real-time RT-PCR (Qrt-PCR), and a telomerase assay and compared the results between HMOS-A, HMOS-P, and human osteosarcoma (HOS) cell lines (MNNG-HOS and Saos-2). RESULTS: The cell biological analysis revealed that HMOS-A and HMOS-P had similar characteristics to Saos-2, and the invasion assay showed that they had similar characteristics to MNNG-HOS. The DNA microarray study showed that the gene expression profiles of HMOS-A and HMOS-P were similar to that of MNNG-HOS, but the overexpression of MMP-2, MMP-9, and MT1-MMP was observed in HMOS-A and HMOS-P, which was correlated with the invasiveness of the extracellular matrix, and collagen type-4 (COL-4) and VEGF were also detected. HMOS-A and HMOS-P showed low telomerase activity similar to Saos-2, which are known to be telomerase negative, but a similar telomere length and telomerase protein to MNNG-HOS. CONCLUSIONS: HMOS-A and HMOS-P demonstrated strong invasive ability, and their gene expression profiles correlated with the invasiveness of the extracellular matrix. Their telomerase activity was low, but they did not shown the typical features of alternative lengthening of telomeres (ALT). HMOS-A and HMOS-P are useful models for further study of various biological aspects and therapeutic manipulation of HMOS.