Functional Comparison of Human and Murine Equilibrative Nucleobase Transporter 1

• Author / Creator

  Kim, Chan S

• 6-Mercaptopurine (6-MP) maintenance therapy is the mainstay for various types of leukemia and inflammatory bowel disease (IBD). 6-MP is associated with numerous adverse effects including gastrointestinal intolerance, myelotoxicity and hepatotoxicity. This can lead to therapy
  discontinuation which is associated with a higher risk of relapse. Drug transporter expression is a known factor for patient variability in drug response and toxicity. We have established that SLC43A3-encoded equilibrative nucleobase transporter 1 (ENBT1) mediates the transport of 6-MP into human lymphocytes and human embryonic kidney 293 (HEK293) cell lines transfected with SLC43A3. ENBT1 is known to be expressed in the gastrointestinal tract, bone marrow, and the liver. However, the relationship between ENBT1 and 6-MP-associated adverse events, or 6-MP pharmacokinetics are not known. To validate the use of a novel slc43a3 knockout (KO) mouse for exploring this relationship, we assessed the functional similarities between human and
  murine ENBT1 using transfected-HEK293 cell lines, MOLT-4 and L1210 leukemia cell lines, and a FL83B hepatic cell line. Based on in silico analysis of structural similarities between
  transporters, we hypothesized that human and murine ENBT1 will have similar 6-MP transport/inhibition kinetics and mediate 6-MP effect on cell viability similarly. Our results show that recombinant and endogenous hENBT1 and mENBT1 are functionally similar in regards to ENBT1-mediated 6-MP cellular accumulation and mediating 6-MP deleterious effect on cell viability.
  Overall, these findings support the utilization of a slc43a3 KO mouse model to explore the role of ENBT1 in 6-MP/6-MP metabolite absorption, cellular accumulation, and tissue biodistribution.

• Subjects / Keywords

  • Membrane Transporters
  • Thiopurines
  • Murine

• Graduation date

  Spring 2024

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-knga-sx83

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.