Glutathione peroxidase 7 suppresses cancer cell growth and is hypermethylated in gastric cancer
Year: 2017
Type: article
Abstract: // Zheng Chen 1 , Tianling Hu 1 , Shoumin Zhu 1 , Kenichi Mukaisho 5 , Wael El-Rifai 1, 2, 3, 4 and Dun-Fa Peng 1 1 Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA 2 Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA 3 Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, USA 4 Department of Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA 5 Department of Pathology, Division of Molecular Diagnostic Pathology, Shiga University of Medical Science, Otsu, Shiga, Japan Correspondence to: Dun-Fa Peng email: [email protected] Keywords: GPX7, stomach, cancer, DNA methylation, tumor suppressor Received: March 17, 2017 Accepted: April 14, 2017 Published: April 29, 2017 ABSTRACT Gastric cancer (GC) is one of the most common cancers in the world, and remains the third leading cause of cancer-related deaths worldwide. Glutathione peroxidase 7 (GPX7) is a member of GPX family which is downregulated in some cancer types. In this study, we investigated the expression, regulation, and molecular function of GPX7 in gastric cancer using 2D and 3D in vitro models and de-identified human tissue samples. Quantitative real-time RT-PCR, immunofluorescence, Western blot, 3D organotypic cultures, and pyrosequencing assays were used. We detected downregulation of GPX7 in all 7 gastric cancer cell lines that we tested and in approximately half (22/45) of human gastric cancer samples, as compared to histologically normal gastric tissues. Quantitative bisulfite pyrosequencing methylation analysis demonstrated DNA hypermethylation (> 10% methylation level) of GPX7 promoter in all 7 gastric cancer cell lines and in 56% (25/45) of gastric cancer samples, as compared to only 13% (6/45) in normal samples ( p < 0.0001). Treatment of AGS and SNU1 cells with 5-Aza-2′-deoxycytidine led to a significant demethylation of GPX7 promoter and restored the expression of GPX7. In vitro assays showed that reconstitution of GPX7 significantly suppressed gastric cancer cell growth in both 2D and 3D organotypic cell culture models. This growth suppression was associated with inhibition of cell proliferation and induction of cell death. We detected significant upregulation of p27 and cleaved PARP and downregulation of Cyclin D1 upon reconstitution of GPX7. Taken together, we conclude that epigenetic silencing of GPX7 could play an important role in gastric tumorigenesis and progression.
Source: Oncotarget
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: diamond
Funders: Vanderbilt University, Vanderbilt University Medical Center, Georgia Clinical and Translational Science Alliance, National Institutes of Health, Vanderbilt Digestive Diseases Research Center, Vanderbilt University Medical Center, National Cancer Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Center for Advancing Translational Sciences
Awards: Targets of Gene Overexpression at 17q in Gastric Tumorigenesis: Darpp32, G2268269956, G2683268942, G3433274139, G364208108, G4020890471, SPORE in GI Cancer, G5679716143, G5853943267, G6297262231, G7520984233, The Vanderbilt Institute for Clinical and Translational Research (VICTR), G9000076948, G9000081609, G9000182424, G9000268584, Molecular and Cellular Basis for Digestive Diseases, Cancer Center Support Grant
OpenAlex ID: W2609408781