Open AccessCellular localization and functional characterization of the equilibrative nucleoside transporters of antitumor nucleosides
Author(s) -
Endo Yoshio,
Obata Tohru,
Murata Daigo,
Ito Mariho,
Sakamoto Kazuki,
Fukushima Masakazu,
Yamasaki Yasundo,
Yamada Yuji,
Natsume Nagato,
Sasaki Takuma
Publication year - 2007
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.1349-7006.2007.00581.x
Subject(s) - nucleoside , nucleoside transporter , cytidine , uridine , intracellular , transporter , nucleoside analogue , cytarabine , biochemistry , biology , cell culture , adenosine , thymidine , chemistry , microbiology and biotechnology , cancer research , in vitro , rna , myeloid leukemia , gene , enzyme , genetics
Nucleoside transporters play an important role in the disposition of nucleosides and their analogs. To elucidate the relationship between chemosensitivity to antitumor nucleosides and the functional expression of equilibrative nucleoside transporters (ENT), we established stable cell lines of human fibrosarcoma HT‐1080 and gastric carcinoma TMK‐1 that constitutively overexpressed green fluorescent protein‐tagged hENT1, hENT2, hENT3 and hENT4. Both hENT1 and hENT2 were predictably localized to the plasma membrane, whereas hENT3 and hENT4 were localized to the intracellular organelles. The chemosensitivity of TMK‐1 cells expressing hENT1 and hENT2 to cytarabine and 1‐(3‐C‐ethynyl‐β‐d‐ribopentofuranosyl) cytosine increased markedly in comparison to that of mock cells. However, no remarkable changes in sensitivity to antitumor nucleosides were observed in cell lines that expressed both hENT3 and hENT4. These data suggest that hENT3 and hENT4, which are mainly located in the intracellular organelles, are not prominent nucleoside transporters like hENT1 and hENT2, which are responsible for antitumor nucleoside uptake. ( Cancer Sci 2007; 98: 1633–1637)