Scutellaria barbata D-Don induces c-fos gene expression in human uterine leiomyomal cells by activating β2-adrenergic receptors

Scutellaria barbata D. Don (Lamiaceae; SB) inhibited the growth of uterine leiomyomal (LM) cells with unknown actions. The expression patterns of beta-adrenergic receptors (beta-ARs) in human uterine LM cells and functional coupling to gene expression have also been investigated. Northern blot analysis showed that beta-AR subtypes are expressed at different levels in the uterine LM cells and myometrial smooth muscle cells (SMCs). beta1-AR expression was to be found approximately at the same level in the two cell types. beta2-ARs were expressed at higher levels in uterine LM cells than that in myometrial SMCs. beta3-AR expression was not found in both the cells. c-fos gene expression was induced by SB in uterine LM cells via increases in adenosine-3',5', cyclic monophosphate (cAMP), which in turn activated the cAMP/protein kinase A (PKA) pathway. The PKA inhibitor, H89, inhibited c-fos gene expression induced by SB. It seems that the mechanism of proto-oncogenes c-fos different leiomyoma from other myometrial cancer. Further studies are necessary to elucidate whether c-fos induction by SB in uterine LM cells influences a regression of leiomyoma or induces other differentiation.