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Abstract: SA-PO977

Increased Renal Elimination of Endogenous and Synthetic Pyrimidine Nucleosides in Concentrative Nucleoside Transporter 1 Deficient Mice

Session Information

  • CKD: Pathobiology - II
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2203 CKD (Non-Dialysis): Mechanisms

Authors

  • Govindarajan, Rajgopal, The Ohio State University, Columbus, Ohio, United States
  • Agrawal, Shipra, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Kaur, Tejinder, The Ohio State University, Columbus, Ohio, United States
  • Ali, Syed Saqib, The Ohio State University, Columbus, Ohio, United States
  • Nayak, Debasis, The Ohio State University, Columbus, Ohio, United States
Background

Concentrative nucleoside transporters (CNTs) are active nucleoside influx systems, but their in vivo roles are poorly defined.

Methods

We generated and characterized global CNT1 knockout (KO) mice to study the role of CNT1 in the renal reabsorption of pyrimidine nucleosides. Mass Spectrometry based metabolomic analyses of mouse urine and plasma samples were conducted to identify changes in small molecules. Orthotopic implantation of pancreatic cancer cells in WT and KO mice was conducted to study the efficacy of chemotherapeutics in tumor-bearing mice. IVIS biolumenisence imaging was conducted to evaluate tumor burden. Kaplan-Meier analysis was conducted to changes in survival.

Results

CRISPR/Cas9 deletion of CNT1 in mice increased the urinary excretion of endogenous pyrimidine nucleosides with compensatory alterations in purine nucleoside metabolism but without impairment of fertility or survival. In addition, CNT1 KO mice exhibited high urinary excretion of the intravenously administered nucleoside analog drug gemcitabine (dFdC), which resulted in decreased systemic drug exposure. However, the increased urinary clearance of dFdC rendered this chemotherapeutic drug ineffective in controlling tumor burden and preventing mortality in CNT1 KO mice orthotopically implanted with syngeneic Kras/p53-mutated mouse pancreatic ductal adenocarcinoma cells.Interestingly, increasing the dFdC dose to attain an area under the concentration-time curve level equivalent to that achieved by wild-type (WT) mice rescued antitumor efficacy and survivability in CNT1 KO mice.

Conclusion

These findings provide new insights into how CNT1 regulates reabsorption of endogenous and synthetic nucleosides in murine kidneys and suggest that the functional status of CNTs should account for the optimal action of pyrimidine nucleoside analog therapeutics in humans. In addition, our studies propose that CNT1 KO mice are an excellent model to further study the role of CNT1 in nucleoside drug-drug interactions, CNT1 genetic polymorphisms, and SLC28A1-mutated human inborn errors of metabolism.

Funding

  • Other NIH Support