Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines

Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines

Citrate is a key intermediate of the tricarboxylic acid cycle and acts as an allosteric signal to regulate the production of cellular ATP. An elevated cytosolic citrate concentration inhibits growth in several types of human cancer cells; however, the underlying mechanism by which citrate induces th...

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Main Authors: Kuang-Chen Hung, Shyang-Guang Wang, Meng-Liang Lin, Shih-Shun Chen
Format: Article
Language:English
Published: MDPI AG 2019-04-01
Series:International Journal of Molecular Sciences
Subjects:
Akt
citrate
cyclin B1
CDK1
p85α
PTEN
G<sub>2</sub>/M
Online Access:https://www.mdpi.com/1422-0067/20/9/2105
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spelling doaj-a69787e9f0064505969b4e009d73590d2020-11-25T02:18:27ZengMDPI AGInternational Journal of Molecular Sciences1422-00672019-04-01209210510.3390/ijms20092105ijms20092105Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell LinesKuang-Chen Hung0Shyang-Guang Wang1Meng-Liang Lin2Shih-Shun Chen3Division of Neurosurgery, Department of Surgery, Taichung Army Force General Hospital, Taichung 41152, TaiwanDepartment of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 40601, TaiwanDepartment of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 40402, TaiwanDepartment of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 40601, TaiwanCitrate is a key intermediate of the tricarboxylic acid cycle and acts as an allosteric signal to regulate the production of cellular ATP. An elevated cytosolic citrate concentration inhibits growth in several types of human cancer cells; however, the underlying mechanism by which citrate induces the growth arrest of cancer cells remains unclear. The results of this study showed that treatment of human pharyngeal squamous carcinoma (PSC) cells with a growth-suppressive concentration of citrate caused cell cycle arrest at the G<sub>2</sub>/M phase. A coimmunoprecipitation study demonstrated that citrate-induced cell cycle arrest in the G<sub>2</sub>/M phase was associated with stabilizing the formation of cyclin B1&#8722;phospho (p)-cyclin-dependent kinase 1 (CDK1) (Thr 161) complexes. The citrate-induced increased levels of cyclin B1 and G<sub>2</sub>/M phase arrest were suppressed by the caspase-3 inhibitor Ac-DEVD-CMK and caspase-3 cleavage of mutant p21 (D112N). Ectopic expression of the constitutively active form of protein kinase B (Akt1) could overcome the induction of p21 cleavage, cyclin B1&#8722;p-CDK1 (Thr 161) complexes, and G<sub>2</sub>/M phase arrest by citrate. p85&#945;&#8722;phosphatase and tensin homolog deleted from chromosome 10 (PTEN) complex-mediated inactivation of Akt was required for citrate-induced G<sub>2</sub>/M phase cell cycle arrest because PTEN short hairpin RNA or a PTEN inhibitor (SF1670) blocked the suppression of Akt Ser 473 phosphorylation and the induction of cyclin B1&#8722;p-CDK1 (Thr 161) complexes and G<sub>2</sub>/M phase arrest by citrate. In conclusion, citrate induces G<sub>2</sub>/M phase arrest in PSC cells by inducing the formation of p85&#945;&#8722;PTEN complexes to attenuate Akt-mediated signaling, thereby causing the formation of cyclin B1&#8722;p-CDK1 (Thr 161) complexes.https://www.mdpi.com/1422-0067/20/9/2105Aktcitratecyclin B1CDK1p85αPTENG<sub>2</sub>/M
collection DOAJ
language English
format Article
sources DOAJ
author Kuang-Chen Hung
Shyang-Guang Wang
Meng-Liang Lin
Shih-Shun Chen
spellingShingle Kuang-Chen Hung
Shyang-Guang Wang
Meng-Liang Lin
Shih-Shun Chen
Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
International Journal of Molecular Sciences
Akt
citrate
cyclin B1
CDK1
p85α
PTEN
G<sub>2</sub>/M
author_facet Kuang-Chen Hung
Shyang-Guang Wang
Meng-Liang Lin
Shih-Shun Chen
author_sort Kuang-Chen Hung
title Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
title_short Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
title_full Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
title_fullStr Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
title_full_unstemmed Citrate-Induced p85α–PTEN Complex Formation Causes G<sub>2</sub>/M Phase Arrest in Human Pharyngeal Squamous Carcinoma Cell Lines
title_sort citrate-induced p85α–pten complex formation causes g<sub>2</sub>/m phase arrest in human pharyngeal squamous carcinoma cell lines
publisher MDPI AG
series International Journal of Molecular Sciences
issn 1422-0067
publishDate 2019-04-01
description Citrate is a key intermediate of the tricarboxylic acid cycle and acts as an allosteric signal to regulate the production of cellular ATP. An elevated cytosolic citrate concentration inhibits growth in several types of human cancer cells; however, the underlying mechanism by which citrate induces the growth arrest of cancer cells remains unclear. The results of this study showed that treatment of human pharyngeal squamous carcinoma (PSC) cells with a growth-suppressive concentration of citrate caused cell cycle arrest at the G<sub>2</sub>/M phase. A coimmunoprecipitation study demonstrated that citrate-induced cell cycle arrest in the G<sub>2</sub>/M phase was associated with stabilizing the formation of cyclin B1&#8722;phospho (p)-cyclin-dependent kinase 1 (CDK1) (Thr 161) complexes. The citrate-induced increased levels of cyclin B1 and G<sub>2</sub>/M phase arrest were suppressed by the caspase-3 inhibitor Ac-DEVD-CMK and caspase-3 cleavage of mutant p21 (D112N). Ectopic expression of the constitutively active form of protein kinase B (Akt1) could overcome the induction of p21 cleavage, cyclin B1&#8722;p-CDK1 (Thr 161) complexes, and G<sub>2</sub>/M phase arrest by citrate. p85&#945;&#8722;phosphatase and tensin homolog deleted from chromosome 10 (PTEN) complex-mediated inactivation of Akt was required for citrate-induced G<sub>2</sub>/M phase cell cycle arrest because PTEN short hairpin RNA or a PTEN inhibitor (SF1670) blocked the suppression of Akt Ser 473 phosphorylation and the induction of cyclin B1&#8722;p-CDK1 (Thr 161) complexes and G<sub>2</sub>/M phase arrest by citrate. In conclusion, citrate induces G<sub>2</sub>/M phase arrest in PSC cells by inducing the formation of p85&#945;&#8722;PTEN complexes to attenuate Akt-mediated signaling, thereby causing the formation of cyclin B1&#8722;p-CDK1 (Thr 161) complexes.
topic Akt
citrate
cyclin B1
CDK1
p85α
PTEN
G<sub>2</sub>/M
url https://www.mdpi.com/1422-0067/20/9/2105
work_keys_str_mv AT kuangchenhung citrateinducedp85aptencomplexformationcausesgsub2submphasearrestinhumanpharyngealsquamouscarcinomacelllines
AT shyangguangwang citrateinducedp85aptencomplexformationcausesgsub2submphasearrestinhumanpharyngealsquamouscarcinomacelllines
AT menglianglin citrateinducedp85aptencomplexformationcausesgsub2submphasearrestinhumanpharyngealsquamouscarcinomacelllines
AT shihshunchen citrateinducedp85aptencomplexformationcausesgsub2submphasearrestinhumanpharyngealsquamouscarcinomacelllines
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