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

doi:10.2147/ott.s141345

Cited by 13 publications

(8 citation statements)

References 34 publications

(48 reference statements)

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“…In addition to increasing apoptosis, our results showing that JQ1 can reduce the hypersecretion of ACTH may also provide a possible treatment for Cushing's syndrome, which is one of the key morbidities of corticotrophinomas (Ntali et al 2013). Thus, JQ1 treatment of AtT20 cells that have been reported to actively secrete ACTH (Buonassisi et al 1962, Gong et al 2014, Asari et al 2017) significantly decreased levels of ACTH in cell media by 48 h and this was preceded by a significant reduction in the expression of Pomc, which encodes pre-pro-opiomelanocortin (pre-pro-POMC) that is cleaved to give rise to multiple peptide hormones, including ACTH (Rousseau et al 2007). Therefore, JQ1 may downregulate ACTH secretion by suppressing expression of the protein it is cleaved from in a BETmediated mechanism.…”

Section: :3mentioning

confidence: 72%

Effects of epigenetic pathway inhibitors on corticotroph tumour AtT20 cells

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Filippakopoulos

Stevenson

et al. 2020

Endocrine-Related Cancer

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Medical treatments for corticotrophinomas are limited, and we therefore investigated the effects of epigenetic modulators, a new class of anti-tumour drugs, on the murine adrenocorticotropic hormone (ACTH)-secreting corticotrophinoma cell line AtT20. We found that AtT20 cells express members of the bromo and extra-terminal (BET) protein family, which bind acetylated histones, and therefore, studied the anti-proliferative and pro-apoptotic effects of two BET inhibitors, referred to as (+)-JQ1 (JQ1) and PFI-1, using CellTiter Blue and Caspase Glo assays, respectively. JQ1 and PFI-1 significantly decreased proliferation by 95% (P < 0.0005) and 43% (P < 0.0005), respectively, but only JQ1 significantly increased apoptosis by >50-fold (P < 0.0005), when compared to untreated control cells. The anti-proliferative effects of JQ1 and PFI-1 remained for 96 h after removal of the respective compound. JQ1, but not PFI-1, affected the cell cycle, as assessed by propidium iodide staining and flow cytometry, and resulted in a higher number of AtT20 cells in the sub G1 phase. RNA-sequence analysis, which was confirmed by qRT-PCR and Western blot analyses, revealed that JQ1 treatment significantly altered expression of genes involved in apoptosis, such as NFκB, and the somatostatin receptor 2 (SSTR2) anti-proliferative signalling pathway, including SSTR2. JQ1 treatment also significantly reduced transcription and protein expression of the ACTH precursor pro-opiomelanocortin (POMC) and ACTH secretion by AtT20 cells. Thus, JQ1 treatment has anti-proliferative and pro-apoptotic effects on AtT20 cells and reduces ACTH secretion, thereby indicating that BET inhibition may provide a novel approach for treatment of corticotrophinomas.

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Section: :3mentioning

confidence: 72%

Effects of epigenetic pathway inhibitors on corticotroph tumour AtT20 cells

Lines

Filippakopoulos

Stevenson

et al. 2020

Endocrine-Related Cancer

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“…The cells were then lysed with Laemmli sample buffer. Lysates were centrifuged, and supernatants were collected, and western blot analyses were performed [17]. In brief, whole cell lysates were heated, and then proteins were separated on a 2-15% gradient polyacrylamide gel and then transferred to a polyvinylidene fluoride membrane (Daiichi Kagaku, Tokyo, Japan).…”

Section: Egfr Quantificationmentioning

confidence: 99%

Ubiquitin-specific protease 8 inhibitor suppresses adrenocorticotropic hormone production and corticotroph tumor cell proliferation

et al. 2020

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Cushing's disease is primarily caused by autonomic hypersecretion of adrenocorticotropic hormone (ACTH) from a pituitary adenoma. In Cushing's disease, mutations in the ubiquitin-specific protease 8 (USP8) have been detected. These mutations are associated with hyperactivation of USP8 that prevent epidermal growth factor receptor (EGFR) degradation. This leads to increased EGFR stability and results in the maintenance of EGFR signaling in Cushing's disease. USP8 inhibitors can suppress the growth of various tumors. In this study, the effects of a potent USP8 inhibitor, DUBs-IN-2, on ACTH production and cell proliferation were examined in mouse corticotroph tumor (AtT-20) cells. Proopiomelanocortin (Pomc) mRNA levels and ACTH levels were decreased in AtT-20 cells by DUBs-IN-2. Further, cell proliferation was inhibited, and apoptosis was induced by DUBs-IN-2. Transcript levels of pituitary tumor-transforming gene 1 (Pttg1), a pituitary tumor growth marker, were increased; and transcript levels of stress response growth arrest and DNA damageinducible 45 (Gadd45β) and Cdk5 and ABL enzyme substrate 1 (Cables1) mRNA levels were increased in response to the drug. Gadd45β or Cables1 knockdown partially inhibited the DUBs-IN-2-induced decrease in cell proliferation, but not Pomc mRNA levels. Both GADD45β and CABLES1 may be responsible, at least in part, for the USP8-induced suppression of corticotroph tumor cell proliferation. USP-8 may be a new treatment target in Cushing's disease.

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“…Janus kinase/signal transducer and activator of transcription (Jak/STAT) is located downstream of EGFR signaling [27] and is essential for EGFR-driven migration and invasion [28]. In our previous study, SD-1029, a potent Jak2 and STAT3 inhibitor, also decreased ACTH synthesis and secretion in corticotroph tumor cells [17]. While AtT-20 cells did not express endogenous EGFR in Fukuoka's report [10], our study shows that EGFR protein is expressed in AtT-20 cells.…”

Section: Discussionmentioning

confidence: 95%

“…The lysates were centrifuged, and the supernatant was recovered. Western blot analysis was performed as described previously [17]. In brief, whole cell lysates were heated, and proteins were separated on a 2-15% gradient polyacrylamide gel and transferred to a polyvinylidene fluoride membrane (Daiichi Kagaku, Tokyo, Japan).…”

Section: Western Blot Analysismentioning

confidence: 99%

Lapatinib decreases the ACTH production and proliferation of corticotroph tumor cells

et al. 2019

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Cushing's disease is almost always caused by hypersecretion of adrenocorticotropic hormone (ACTH) from a pituitary adenoma. A mutation in the deubiquitinase gene USP8 has been found in human ACTH-producing pituitary adenoma cells. This mutational hotspot hyperactivates USP8, rescuing epidermal growth factor receptor (EGFR) from lysosomal degradation and ensuring its sustained signaling in Cushing's disease. An EGFR inhibitor would be an effective anti-tumor agent in EGFR-related tumors. We investigated the effect of a potent dual tyrosine kinase inhibitor, lapatinib, on ACTH production and cell proliferation in AtT-20 mouse corticotroph tumor cells. Lapatinib decreased proopiomelanocortin (Pomc) mRNA levels and ACTH levels in AtT-20 cells and also inhibited cell proliferation, induced apoptosis, and decreased pituitary tumor-transforming gene 1 (Pttg1), a hallmark of pituitary tumors, mRNA levels. KSN/Slc nude mice were subcutaneously inoculated with AtT-20 cells. After 1 week, the mice were randomized either to control or lapatinib groups. The inhibitor decreased the tumor weight of AtT-20 allografts in vivo versus control mice. Lapatinib also significantly decreased Pomc and Pttg1 mRNA levels in the tumor and plasma ACTH and corticosterone levels in vivo. Thus, lapatinib decreases the ACTH production and proliferation of corticotroph tumor cells. An EGFR-targeting therapy could be an important treatment for Cushing's disease.

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Inhibitory effects of a selective Jak2 inhibitor on adrenocorticotropic hormone production and proliferation of corticotroph tumor AtT20 cells

Cited by 13 publications

References 34 publications

Effects of epigenetic pathway inhibitors on corticotroph tumour AtT20 cells

Effects of epigenetic pathway inhibitors on corticotroph tumour AtT20 cells

Ubiquitin-specific protease 8 inhibitor suppresses adrenocorticotropic hormone production and corticotroph tumor cell proliferation

Lapatinib decreases the ACTH production and proliferation of corticotroph tumor cells

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