{'fraction_non_alphanumeric': 0.03228228228228228, 'fraction_numerical': 0.015765765765765764, 'mean_word_length': 4.7956521739130435, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
BMP-2 inhibits the tumorigenicity of cancer stem cells in human osteosarcoma OS99-1 cell line

Previously, based on high ALDH activity, we showed that cancer stem cells (CSCs) could be identified as ALDHbr cells from an aggressive human osteosarcoma OS99-1 cell line. In this study, we evaluate the impact of BMP-2 on CSCs.Three types of BMP receptors were expressed in freshly sorted ALDHbr cells. In vitro, growth of the sorted ALDHbr cells was inhibited by BMP-2. Using RT-PCR analysis, BMP-2 was found to down-regulate the expression of embryonic stem cell markers Oct3/4, Nanog, and Sox-2, and up-regulate the transcription of osteogenic markers Runx-2 and Collagen Type I. In vivo, all animals receiving ALDHbr cells treated with BMP-2 did not form significant tumors, while untreated ALDHbr cells developed large tumor masses in NOD/SCID mice. Immunostaining confirmed few Ki-67 positive cells were present in the sections of tumor containing ALDHbr cells treated with BMP-2. These results suggest that BMP-2 suppresses tumor growth by reducing the gene expression of tumorigenic factors and inducing the differentiation of CSCs in osteosarcoma. BMP-2 or BMP-2-mimetic drugs, if properly delivered to tumor and combined with traditional therapies, may therefore provide a new therapeutic option for treatment of osteosarcoma.