Effect of bee venom on aromatase expression and activity in leukaemic FLG 29.1 and primary osteoblastic cells

The effect of bee venom aqua-acupuncture (BVA) (api-toxin), a traditional immunosuppressive Korean aqua-acupuncture, on the bone function in human osteoblastic cells was studied. To provide insights into the effect of BVA on aromatase activity in bone-derived cells, we examined the human leukaemic cell line FLG 29.1, which is induced to differentiate toward the osteoclastic phenotype by TPA and TGF-beta1, and the primary first-passage osteoblastic cells (hOB). Southern blot of RT-PCR products with a 32P-labeled cDNA probe for the human aromatase demonstrated that FLG 29.1 and hOB cells express aromatase mRNA. Gene expression and enzyme activity were stimulated in a time-dependent fashion by 5.0 microl/ml BV and by either 1-50 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure. After 24 h incubation of the cells in the absence of these stimuli the aromatase mRNA and the protein were barely detectable. These findings demonstrate that cells of the osteoclastic lineage synthesize aromatase in vitro by the local cytokine of TGF-beta1 and BVA. These can offer an explanation for the lack of development of osteoarthritis in BVA-treated patients.