Levels of human equilibrative nucleoside transporter-1 are higher in proliferating regions of A549 tumor cells grown as tumor xenografts in vivo

David A. Plotnik, Camille Asher, Stephanie K. Chu, Robert S. Miyaoka, Gregory G. Garwin, Brian W. Johnson, Tiffany Li, Kenneth A. Krohn, Jeffrey L. Schwartz

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

3'-Fluoro-3'-deoxythymidine (FLT) has been proposed for positron emission tomography (PET)-based identification of tumor chemosensitivity that is mediated by the human equilibrative nucleoside transporter-1 (ENT1). ENT1 facilitates transport of FLT into cells and elevated levels of FLT are associated with both larger FLT-PET signals and increased response to nucleoside-based chemotherapies. FLT-PET is also used as a measure of tumor proliferation. The present study examined the extent to which ENT1 levels vary in a proliferation-dependent manner in tumor cells in vivo. Methods: The human adenocarcinoma cell line A549 was used to establish tumor xenografts in nude mice. FLT uptake was measured in vivo using PET, and further examined ex vivo using autoradiography. FLT uptake patterns were compared to immunohistochemical (IHC) analysis of ENT1 and the proliferation markers Ki67 and BrdU. Results: Regional differences in FLT uptake matched differences in IHC proliferation markers. All cells stained for ENT1, but the staining intensity was twice as high for Ki67+ cells than for Ki67- cells. Conclusions: Under in vivo conditions, proliferating regions of tumors show increased FLT uptake and higher ENT1 levels than nonproliferating tumor regions.

Original languageEnglish (US)
Pages (from-to)1161-1166
Number of pages6
JournalNuclear Medicine and Biology
Volume39
Issue number8
DOIs
StatePublished - Nov 2012

Keywords

  • ENT1
  • FLT-PET Imaging
  • Ki67
  • Tumor Cell Proliferation

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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