title: Negative regulation of parathyroid hormone-related protein expression by steroid hormones.
abstract: Elevated parathyroid hormone-related protein (PTHrP) is responsible for humoral hypercalcemia of malignancy (HHM), which is of clinical significance in treatment of terminal patients with malignancies. Steroid hormones were known to cause suppression of PTHrP expression. However, detailed studies linking multiple steroid hormones to PTHrP expression are lacking. Here we studied PTHrP expression in response to steroid hormones in four cell lines with excessive PTHrP production. Our study established that steroid hormones negatively regulate PTHrP expression. Vitamin D receptor, estrogen receptor α, glucocorticoid receptor, and progesterone receptor, were required for repression of PTHrP expression by the cognate ligands. A notable exception was the androgen receptor, which was dispensable for suppression of PTHrP expression in androgen-treated cells. We propose a pathway(s) involving nuclear receptors to suppress PTHrP expression.
authors.affiliation: Department of Biochemistry, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kajitani
authors.forename: Mimi
authors.initials: M
authors.lastname: Tamamori-Adachi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Okinaga
authors.forename: Minoru
authors.initials: M
authors.lastname: Chikamori
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Iizuka
authors.forename: Tomoki
authors.initials: T
authors.lastname: Okazaki
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D015536:Down-Regulation; D006728:Hormones / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D044162:Parathyroid Hormone-Related Protein / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D013256:Steroids / Q000494:pharmacology / Q000502:physiology*
chemical_list: D006728:Hormones; D044162:Parathyroid Hormone-Related Protein; D013256:Steroids