BACKGROUND: The rediscovery of 5-hydroxymethylcytosine, the ten-eleven translocation (TET) family, thymine-DNA glycosylase (TDG) and isocitrate dehydrogenase (IDH) have opened new avenues in the study of DNA demethylation pathways in gastric cancer (GC). We performed a comprehensive and robust analysis of these genes and modified cytosines in gastric cancer. METHODS: Liquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS) was used to assess 5-methyldeoxycytidine (5-mC), 5-hydroxymethyldeoxycytidine (5-hmC), 5-formyldeoxycytidine (5-fC) and 5-carboxyldeoxycytidine (5-caC) quantitatively in tumorous and non-tumorous regions of GCs; [D2]-5-hmC was used as an internal standard. Expression levels of the genes TET1, TET2, TET3, TDG, IDH1 and IDH2 were measured using a real-time reverse transcription polymerase chain reaction (RT-PCR) and were compared to the clinical attributes of each case. Using HEK293T cells the effects of introducing plasmids containing full-length TET1, TET2, and TET3 and 7 variants of the TET2 catalytic domain were evaluated in terms of their effect on cytosine demethylation. RESULTS: LC-MS/MS showed that 5-hmC was significantly decreased in tumorous portions. 5-mC was also moderately decreased in tumors, while 5-fC and 5-caC were barely detectable. The expressions of TET1, TET2, TET3, TDG and IDH2, but not IDH1, were notably decreased in GCs, compared with the adjacent non-tumor portion. TET1 expression and the 5-hmC levels determined using LC-MS/MS had a significantly positive correlation and TET1 protein had a greater effect on the increase in 5-hmC than TET2 and TET3 in HEK293T cells. CONCLUSIONS: The loss of 5-hmC and the down-regulation of TET1-3, TDG and IDH2 were found in GCs. The loss of 5-hmC in GCs was mainly correlated with the down-regulation of TET1.
BACKGROUND: The rediscovery of 5-hydroxymethylcytosine, the ten-eleven translocation (TET) family, thymine-DNA glycosylase (TDG) and isocitrate dehydrogenase (IDH) have opened new avenues in the study of DNA demethylation pathways in gastric cancer (GC). We performed a comprehensive and robust analysis of these genes and modified cytosines in gastric cancer. METHODS: Liquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS) was used to assess 5-methyldeoxycytidine (5-mC), 5-hydroxymethyldeoxycytidine (5-hmC), 5-formyldeoxycytidine (5-fC) and 5-carboxyldeoxycytidine (5-caC) quantitatively in tumorous and non-tumorous regions of GCs; [D2]-5-hmC was used as an internal standard. Expression levels of the genes TET1, TET2, TET3, TDG, IDH1 and IDH2 were measured using a real-time reverse transcription polymerase chain reaction (RT-PCR) and were compared to the clinical attributes of each case. Using HEK293T cells the effects of introducing plasmids containing full-length TET1, TET2, and TET3 and 7 variants of the TET2 catalytic domain were evaluated in terms of their effect on cytosine demethylation. RESULTS: LC-MS/MS showed that 5-hmC was significantly decreased in tumorous portions. 5-mC was also moderately decreased in tumors, while 5-fC and 5-caC were barely detectable. The expressions of TET1, TET2, TET3, TDG and IDH2, but not IDH1, were notably decreased in GCs, compared with the adjacent non-tumor portion. TET1 expression and the 5-hmC levels determined using LC-MS/MS had a significantly positive correlation and TET1 protein had a greater effect on the increase in 5-hmC than TET2 and TET3 in HEK293T cells. CONCLUSIONS: The loss of 5-hmC and the down-regulation of TET1-3, TDG and IDH2 were found in GCs. The loss of 5-hmC in GCs was mainly correlated with the down-regulation of TET1.
Authors: Mary A Selak; Sean M Armour; Elaine D MacKenzie; Houda Boulahbel; David G Watson; Kyle D Mansfield; Yi Pan; M Celeste Simon; Craig B Thompson; Eyal Gottlieb Journal: Cancer Cell Date: 2005-01 Impact factor: 31.743
Authors: Philip J Stephens; Patrick S Tarpey; Helen Davies; Peter Van Loo; Chris Greenman; David C Wedge; Serena Nik-Zainal; Sancha Martin; Ignacio Varela; Graham R Bignell; Lucy R Yates; Elli Papaemmanuil; David Beare; Adam Butler; Angela Cheverton; John Gamble; Jonathan Hinton; Mingming Jia; Alagu Jayakumar; David Jones; Calli Latimer; King Wai Lau; Stuart McLaren; David J McBride; Andrew Menzies; Laura Mudie; Keiran Raine; Roland Rad; Michael Spencer Chapman; Jon Teague; Douglas Easton; Anita Langerød; Ming Ta Michael Lee; Chen-Yang Shen; Benita Tan Kiat Tee; Bernice Wong Huimin; Annegien Broeks; Ana Cristina Vargas; Gulisa Turashvili; John Martens; Aquila Fatima; Penelope Miron; Suet-Feung Chin; Gilles Thomas; Sandrine Boyault; Odette Mariani; Sunil R Lakhani; Marc van de Vijver; Laura van 't Veer; John Foekens; Christine Desmedt; Christos Sotiriou; Andrew Tutt; Carlos Caldas; Jorge S Reis-Filho; Samuel A J R Aparicio; Anne Vincent Salomon; Anne-Lise Børresen-Dale; Andrea L Richardson; Peter J Campbell; P Andrew Futreal; Michael R Stratton Journal: Nature Date: 2012-05-16 Impact factor: 49.962
Authors: Shinsuke Ito; Ana C D'Alessio; Olena V Taranova; Kwonho Hong; Lawrence C Sowers; Yi Zhang Journal: Nature Date: 2010-08-26 Impact factor: 49.962
Authors: Dorota Ewa Bronowicka-Kłys; Andrzej Roszak; Piotr Pawlik; Stefan Sajdak; Anna Sowińska; Paweł Piotr Jagodziński Journal: Oncol Lett Date: 2017-03-28 Impact factor: 2.967