| Research Abstract |
1. Northern and Western blottings demonstrated that human salivary adenocarcinoma cell's subclone (HSG-S8) expressed bone morphogenetic protein (BMP)-2mRNA, and secreted BMP proteins into the medium in serum free culture. BMP-1, -3, and -4 mRAN were not expressed. Retinoic acid (RA, all-trans, 1 mu M) strongly up-regulated the expression of BMP-2 mRNA by the treatment for 6-48 hrs. The BMP-2 proteins in conditined medium also increased 5-fold by the treatment of 1 mu M RA for 48 hrs. Simultaneously, RA suppressed the growth of HSG-S8 cells through down-regulation of the expression of c-myc. Cells did not show particular morphological features of cellular differentiation by treatment of RA.
2. When HSG-S8 cells transplanted into athymic nude mice subcutaneously or intramauscularly, these cells also produced BMP-2 and focally secreted in vivo, which induced heterotopic ossification (s.c.) and cartilage formation (i.m) in the tumos formed by HSG-S8.
3. Immunohistochemistry did not show imunoreations of both of anti-BMP-2(from Genetics Institute R230) and -3(from Genetics Institute, SM10) antibodies to celles of the parotid, submandibular, palatal, and labial glands. Only anti-BMP-1 anti-body immunoreacted to degenerated acinar cells of the submandibular gland. In pleomorphic adenoma, the glandular, solid plasmacytoid, and some spindle tumor cells were positive to anti-BMP(s) antibodies. These findings were observed not only in pleomorphic adenoma with cartilage area, but also without cartilage. In cartilage area, some cells were positive to BMP(s). It was suggested that other factors related to the formation of cartilage area in pleomorphic adenoma.
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