Epigenetic regulators in osteosarcoma stem cells
Imprinting gene TSSC3
Genomic imprinting is the epigenetic modification of gene loci resulting in altered allelic expression. A malignant-transformed osteosarcoma cell line (MTF) has been developed in our laboratory composed primarily of OSCs capable of forming spheres [70]. Microarray analysis identified 10 imprinting genes that were aberrantly expressed, including tumor-suppressing STF cDNA 3 (TSSC3) in this cell line. This imprinting gene is related to cell death and was significantly downregulated [70]. Overexpression of TSSC3 has also been reported to suppress cell vitality and growth, induce apoptosis and downregulate expressions of Oct4, Sox2 and Nanog in osteosarcoma cells, leading to dramatic reductions in the OSC phenotype [35] and [48].