title: Functional upregulation of the H2S/Cav3.2 channel pathway accelerates secretory function in neuroendocrine-differentiated human prostate cancer cells.
abstract: Neuroendocrine-differentiated prostate cancer cells may contribute to androgen-independent proliferation of surrounding cells through Ca(2+)-dependent secretion of mitogenic factors. Human prostate cancer LNCaP cells, when neuroendocrine-differentiated, overexpress Cav3.2 T-type Ca(2+) channels that contribute to Ca(2+)-dependent secretion. Given evidence for the acceleration of Cav3.2 activity by hydrogen sulfide (H2S), we examined the roles of the H2S/Cav3.2 pathway and then analyzed the molecular mechanisms of the Cav3.2 overexpression in neuroendocrine-differentiated LNCaP cells. LNCaP cells were differentiated by dibutyryl cyclic AMP. Protein levels and T-type Ca(2+) channel-dependent currents (T-currents) were measured by immunoblotting and whole-cell pacth-clamp technique, respectively. Spontaneous release of prostatic acid phosphatase (PAP) was monitored to evaluate secretory function. The differentiated LNCaP cells exhibited neurite outgrowth, androgen-independent proliferation and upregulation of mitogenic factors, and also showed elevation of Cav3.2 expression or T-currents. Expression of cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS), H2S-forming enzymes, and spontaneous secretion of PAP increased following the differentiation. The augmented T-currents were enhanced by H2S donors and suppressed by inhibitors of CSE, but not CBS. The PAP secretion was reduced by inhibition of CSE or T-type Ca(2+) channels. During differentiation, Egr-1 and REST, positive and negative transcriptional regulators for Cav3.2, were upregulated and downregulated, respectively, and Egr-1 knockdown prevented the Cav3.2 overexpression. Our data suggest that, in neuroendocrine-differentiated LNCaP cells, H2S formed by the upregulated CSE promotes the activity of the upregulated Cav3.2, leading to the elevated secretory functions. The overexpression of Cav3.2 appears to involve upregulation of Egr-1 and downregulation of REST.
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: a_smile_bring_up_a_happy_mind9@yahoo.co.jp.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Fukami
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: fumiko@phar.kindai.ac.jp.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Sekiguchi
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: raintree.blossom.57@gmail.com.
authors.forename: Miku
authors.initials: M
authors.lastname: Yasukawa
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: 1111610150f@kindai.ac.jp.
authors.forename: Erina
authors.initials: E
authors.lastname: Asano
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: cfado303@jtw.zaq.ne.jp.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kasamatsu
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: 1211610011n@kindai.ac.jp.
authors.forename: Mai
authors.initials: M
authors.lastname: Ueda
authors.affiliation: Department of Life Science, Faculty of Science and Engineering, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: physiology@life.kindai.ac.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yoshida
authors.affiliation: Division of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka 577-8502, Japan. Electronic address: kawabata@phar.kindai.ac.jp.
authors.forename: Atsufumi
authors.initials: A
authors.lastname: Kawabata
mesh_terms: D020747:Calcium Channels, T-Type / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051766:Early Growth Response Protein 1 / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D055099:Neuroendocrine Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009496:Neurotensin / Q000378:metabolism; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D012097:Repressor Proteins / Q000378:metabolism; D015854:Up-Regulation; D000099229:RE1-Silencing Transcription Factor
chemical_list: D020747:Calcium Channels, T-Type; D051766:Early Growth Response Protein 1; D006862:Hydrogen Sulfide; D009496:Neurotensin; D044162:Parathyroid Hormone-Related Protein; D012097:Repressor Proteins; D000099229:RE1-Silencing Transcription Factor; C479952:CACNA1H protein, human; C497325:EGR1 protein, human
keywords: Hydrogen sulfide; Neuroendocrine differentiation; Prostate cancer; T-type calcium channel