EXPRESSION OF BONE MORPHOGENETIC PROTEINS IN HUMAN OSTEOGENIC AND EPITHELIAL TUMOR-CELLS

In addition to osteosarcomas some epithelial tumors also show bone ind uction, which is supposedly due to bone morphogenetic proteins (BMPs). However, the types of BMPs expressed in different kinds of tumors hav e not been studied extensively. In this study five human osteosarcoma and six human carcinoma cell lines were examined to investigate the bo ne induction and BMP mRNA expression. The cultured cells were transpla nted in the subcutaneous tissue of athymic nude mice with or without d iffusion chambers, Reverse transcription-polymerase chain reaction (RT -PCR) was used for the detection of BMP mRNAs. All osteosarcoma cell l ines expressing all BMPs (BMP-I to 7) examined, successfully formed bo ne or osteoid tissue irrespective of the use of a diffusion chamber. B one formation was induced by diffusion chamber in an osteosarcoma cell line OST and a gastric adenocarcinoma cell line MKN45. OST cells lack ed BMP-3 and 7, and MKN45 cells lacked BMP-3, 5 and 6. Our data sugges t that BMP-3, 5, 6 and 7 are not always essential for bone induction i n tumor cells.