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Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells
PURPOSE: The primary cause of Cushing’s disease is adrenocorticotropic hormone (ACTH)-producing pituitary adenomas. EGFR signaling induces POMC mRNA-transcript levels and ACTH secretion from corticotroph tumors. The Jak–STAT pathway is located downstream of EGFR signaling; therefore, a Jak2 inhibito...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Dove Medical Press
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590765/ https://www.ncbi.nlm.nih.gov/pubmed/28919782 http://dx.doi.org/10.2147/OTT.S141345 |
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author | Asari, Yuko Kageyama, Kazunori Nakada, Yuki Tasso, Mizuki Takayasu, Shinobu Niioka, Kanako Ishigame, Noriko Daimon, Makoto |
author_facet | Asari, Yuko Kageyama, Kazunori Nakada, Yuki Tasso, Mizuki Takayasu, Shinobu Niioka, Kanako Ishigame, Noriko Daimon, Makoto |
author_sort | Asari, Yuko |
collection | PubMed |
description | PURPOSE: The primary cause of Cushing’s disease is adrenocorticotropic hormone (ACTH)-producing pituitary adenomas. EGFR signaling induces POMC mRNA-transcript levels and ACTH secretion from corticotroph tumors. The Jak–STAT pathway is located downstream of EGFR signaling; therefore, a Jak2 inhibitor could be an effective therapy for EGFR-related tumors. In this study, we determined the effect of a potent and selective Jak2 inhibitor, SD1029, on ACTH production and proliferation in mouse AtT20 corticotroph tumor cells. MATERIALS AND METHODS: AtT20 pituitary corticotroph tumor cells were cultured after transfection with PTTG1- or GADD45β-specific siRNA. Expression levels of mouse POMC, PTTG1, and GADD45β mRNAs were evaluated using quantitative real-time polymerase chain reaction. ACTH levels were measured using ACTH ELISA. Western blot analysis was performed to examine protein expression of phosphorylated STAT3/STAT3. Viable cells and DNA fragmentation were measured using a cell-proliferation assay and cell-death detection ELISA, respectively. Cellular DNA content was analyzed using fluorescence-activated cell sorting. RESULTS: SD1029 decreased POMC and PTTG1 mRNA and ACTH levels, while increasing GADD45β levels. The drug also decreased AtT20-cell proliferation and induced apoptosis, but did not alter cell-cycle progression. SD1029 also inhibited STAT3 phosphorylation. PTTG1 knockdown inhibited POMC mRNA levels and cell proliferation. However, combined treatment with PTTG1 knockdown and SD1029 had no additive effect on POMC mRNA levels or cell proliferation. GADD45β knockdown inhibited the SD1029-induced decrease in POMC mRNA levels and also partially inhibited the decrease in cell proliferation. CONCLUSION: Both PTTG1 and GADD45β may be responsible, at least in part, for the Jak2-induced suppression of ACTH synthesis and cell proliferation. Accordingly, therapies that target EGFR-dependent Jak2/STAT3 may have clinical applications for treating Cushing’s disease. |
format | Online Article Text |
id | pubmed-5590765 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Dove Medical Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-55907652017-09-15 Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells Asari, Yuko Kageyama, Kazunori Nakada, Yuki Tasso, Mizuki Takayasu, Shinobu Niioka, Kanako Ishigame, Noriko Daimon, Makoto Onco Targets Ther Original Research PURPOSE: The primary cause of Cushing’s disease is adrenocorticotropic hormone (ACTH)-producing pituitary adenomas. EGFR signaling induces POMC mRNA-transcript levels and ACTH secretion from corticotroph tumors. The Jak–STAT pathway is located downstream of EGFR signaling; therefore, a Jak2 inhibitor could be an effective therapy for EGFR-related tumors. In this study, we determined the effect of a potent and selective Jak2 inhibitor, SD1029, on ACTH production and proliferation in mouse AtT20 corticotroph tumor cells. MATERIALS AND METHODS: AtT20 pituitary corticotroph tumor cells were cultured after transfection with PTTG1- or GADD45β-specific siRNA. Expression levels of mouse POMC, PTTG1, and GADD45β mRNAs were evaluated using quantitative real-time polymerase chain reaction. ACTH levels were measured using ACTH ELISA. Western blot analysis was performed to examine protein expression of phosphorylated STAT3/STAT3. Viable cells and DNA fragmentation were measured using a cell-proliferation assay and cell-death detection ELISA, respectively. Cellular DNA content was analyzed using fluorescence-activated cell sorting. RESULTS: SD1029 decreased POMC and PTTG1 mRNA and ACTH levels, while increasing GADD45β levels. The drug also decreased AtT20-cell proliferation and induced apoptosis, but did not alter cell-cycle progression. SD1029 also inhibited STAT3 phosphorylation. PTTG1 knockdown inhibited POMC mRNA levels and cell proliferation. However, combined treatment with PTTG1 knockdown and SD1029 had no additive effect on POMC mRNA levels or cell proliferation. GADD45β knockdown inhibited the SD1029-induced decrease in POMC mRNA levels and also partially inhibited the decrease in cell proliferation. CONCLUSION: Both PTTG1 and GADD45β may be responsible, at least in part, for the Jak2-induced suppression of ACTH synthesis and cell proliferation. Accordingly, therapies that target EGFR-dependent Jak2/STAT3 may have clinical applications for treating Cushing’s disease. Dove Medical Press 2017-09-01 /pmc/articles/PMC5590765/ /pubmed/28919782 http://dx.doi.org/10.2147/OTT.S141345 Text en © 2017 Asari et al. This work is published and licensed by Dove Medical Press Limited The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. |
spellingShingle | Original Research Asari, Yuko Kageyama, Kazunori Nakada, Yuki Tasso, Mizuki Takayasu, Shinobu Niioka, Kanako Ishigame, Noriko Daimon, Makoto Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title | Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title_full | Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title_fullStr | Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title_full_unstemmed | Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title_short | Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells |
title_sort | inhibitory effects of a selective jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor att20 cells |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590765/ https://www.ncbi.nlm.nih.gov/pubmed/28919782 http://dx.doi.org/10.2147/OTT.S141345 |
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