Open AccessDisrupted plasma membrane localization of equilibrative nucleoside transporter 2 in the chemoresistance of human pancreatic cells to gemcitabine (dFdCyd)
Author(s) -
Nishio Ren,
Tsuchiya Hiroyuki,
Yasui Toshihiro,
Matsuura Shizuka,
Kanki Keita,
Kurimasa Akihiro,
Hisatome Ichiro,
Shiota Goshi
Publication year - 2011
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2010.01837.x
Subject(s) - gemcitabine , cytidine deaminase , deoxycytidine kinase , pancreatic cancer , cancer research , nucleoside transporter , nucleoside , biology , deoxycytidine , cytidine , microbiology and biotechnology , chemistry , cancer , biochemistry , enzyme , transporter , gene , genetics
Although the nucleoside pyrimidine analogue gemcitabine is the most effective single agent in the palliation of advanced pancreatic cancer, cellular resistance to gemcitabine treatment is a major problem in the clinical scene. To clarify the molecular mechanisms responsible for chemoresistance to gemcitabine, mRNA expression of the key enzymes including cytidine deaminase (CDA), deoxycytidine kinase (dCK), 5′‐nucleotidase (NT5), equilibrative nucleoside transporter 1 and 2 (ENT1 and ENT2), dCMP deaminase (dCMPK), ribonucleotide reductase M1 and M2 (RRM1 and RRM2), thymidylate synthase (TS) and CTP synthase (CTPS) was examined. The interacellular uptake of gemcitabine was greatly impaired in the chemoresistant cell lines due to dysfunction of ENT1 and ENT2. Protein expression of ENT1 and ENT2 and their protein coding sequences were not altered. Immunohistochemical and western blot analyses revealed that localization of ENT2 on the plasma membrane was disrupted. These data suggest that the disrupted localization of ENT2 is one of causes of the impaired uptake of gemcitabine, resulting in a gain of chemoresistance to gemcitabine. ( Cancer Sci 2011; 102: 622–629)