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Cytosolic 5'-nucleotidase 1A is overexpressed in pancreatic cancer and mediates gemcitabine resistance by reducing intracellular gemcitabine metabolites.

Published version
Peer-reviewed

Type

Article

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Authors

Patzak, Melanie S 
Kari, Vijayalakshmi 
Patil, Shilpa 
Hamdan, Feda H 
Goetze, Robert G 

Abstract

BACKGROUND: Cytosolic 5'-nucleotidase 1A (NT5C1A) dephosphorylates non-cyclic nucleoside monophosphates to produce nucleosides and inorganic phosphates. Here, we investigate NT5C1A expression in pancreatic ductal adenocarcinoma (PDAC) and its impact on gemcitabine metabolism and therapeutic efficacy. METHODS: NT5C1A expression was determined by semiquantitative immunohistochemistry using tissue microarrays. Gemcitabine metabolites and response were assessed in several human and murine PDAC cell lines using crystal violet assays, Western blot, viability assays, and liquid chromatography tandem mass-spectrometry (LC-MS/MS). FINDINGS: NT5C1A was strongly expressed in tumor cells of a large subgroup of resected PDAC patients in two independent patient cohorts (44-56% score 2 and 8-26% score 3, n = 414). In contrast, NT5C1A was expressed at very low levels in the tumor stroma, and neither stromal nor tumoral expression was a prognostic marker for postoperative survival. In vitro, NT5C1A overexpression increased gemcitabine resistance by reducing apoptosis levels and significantly decreased intracellular amounts of cytotoxic dFdCTP in +NT5C1A tumor cells. Co-culture experiments with conditioned media from +NT5C1A PSCs improved gemcitabine efficacy in tumor cells. In vivo, therapeutic efficacy of gemcitabine was significantly decreased and serum levels of the inactive gemcitabine metabolite dFdU significantly increased in mice bearing NT5C1A overexpressing tumors. INTERPRETATION: NT5C1A is robustly expressed in tumor cells of resected PDAC patients. Moreover, NT5C1A mediates gemcitabine resistance by decreasing the amount of intracellular dFdCTP, leading to reduced tumor cell apoptosis and larger pancreatic tumors in mice. Further studies should clarify the role of NT5C1A as novel predictor for gemcitabine treatment response in patients with PDAC.

Description

Keywords

Chemotherapeutic resistance, Cytosolic 5′-nucleotidase 1A, Gemcitabine, Pancreatic cancer, 5'-Nucleotidase, Animals, Biomarkers, Tumor, Carcinoma, Pancreatic Ductal, Cell Line, Tumor, Deoxycytidine, Disease Models, Animal, Drug Resistance, Neoplasm, Gene Expression, Humans, Mice, Mice, Transgenic, Models, Biological, Pancreatic Neoplasms, Prognosis, Xenograft Model Antitumor Assays, Gemcitabine

Journal Title

EBioMedicine

Conference Name

Journal ISSN

2352-3964
2352-3964

Volume Title

40

Publisher

Elsevier BV
Sponsorship
Cancer Research UK (CB4270)
Cancer Research UK (C14303/A17197)
Cancer Research UK (15678)