Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
  • Clinical Research and Public Health
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • Conversations with Giants in Medicine
    • Video Abstracts
  • Reviews
    • View all reviews ...
    • Pancreatic Cancer (Jul 2025)
    • Complement Biology and Therapeutics (May 2025)
    • Evolving insights into MASLD and MASH pathogenesis and treatment (Apr 2025)
    • Microbiome in Health and Disease (Feb 2025)
    • Substance Use Disorders (Oct 2024)
    • Clonal Hematopoiesis (Oct 2024)
    • Sex Differences in Medicine (Sep 2024)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Clinical Research and Public Health
    • Research Letters
    • Letters to the Editor
    • Editorials
    • Commentaries
    • Editor's notes
    • Reviews
    • Viewpoints
    • 100th anniversary
    • Top read articles

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • Conversations with Giants in Medicine
  • Video Abstracts
  • In-Press Preview
  • Clinical Research and Public Health
  • Research Letters
  • Letters to the Editor
  • Editorials
  • Commentaries
  • Editor's notes
  • Reviews
  • Viewpoints
  • 100th anniversary
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
A dyad of lymphoblastic lysosomal cysteine proteases degrades the antileukemic drug l-asparaginase
Naina Patel, … , Paul A. Bates, Vaskar Saha
Naina Patel, … , Paul A. Bates, Vaskar Saha
Published June 8, 2009
Citation Information: J Clin Invest. 2009;119(7):1964-1973. https://doi.org/10.1172/JCI37977.
View: Text | PDF
Research Article Oncology

A dyad of lymphoblastic lysosomal cysteine proteases degrades the antileukemic drug l-asparaginase

  • Text
  • PDF
Abstract

l-Asparaginase is a key therapeutic agent for treatment of childhood acute lymphoblastic leukemia (ALL). There is wide individual variation in pharmacokinetics, and little is known about its metabolism. The mechanisms of therapeutic failure with l-asparaginase remain speculative. Here, we now report that 2 lysosomal cysteine proteases present in lymphoblasts are able to degrade l-asparaginase. Cathepsin B (CTSB), which is produced constitutively by normal and leukemic cells, degraded asparaginase produced by Escherichia coli (ASNase) and Erwinia chrysanthemi. Asparaginyl endopeptidase (AEP), which is overexpressed predominantly in high-risk subsets of ALL, specifically degraded ASNase. AEP thereby destroys ASNase activity and may also potentiate antigen processing, leading to allergic reactions. Using AEP-mediated cleavage sequences, we modeled the effects of the protease on ASNase and created a number of recombinant ASNase products. The N24 residue on the flexible active loop was identified as the primary AEP cleavage site. Sole modification at this site rendered ASNase resistant to AEP cleavage and suggested a key role for the flexible active loop in determining ASNase activity. We therefore propose what we believe to be a novel mechanism of drug resistance to ASNase. Our results may help to identify alternative therapeutic strategies with the potential of further improving outcome in childhood ALL.

Authors

Naina Patel, Shekhar Krishnan, Marc N. Offman, Marcin Krol, Catherine X. Moss, Carly Leighton, Frederik W. van Delft, Mark Holland, JiZhong Liu, Seema Alexander, Clare Dempsey, Hany Ariffin, Monika Essink, Tim O.B. Eden, Colin Watts, Paul A. Bates, Vaskar Saha

×

Figure 1

ASNase is degraded by cysteine proteases present in pre–B lymphoblasts.

Options: View larger image (or click on image) Download as PowerPoint
ASNase is degraded by cysteine proteases present in pre–B lymphoblasts.
...
Immunoblotting for ASNase following incubation of ASNase with whole-cell lysates from cell lines. (A) ASNase is cleaved by cellular lysates of REH, SD1, and HRC57. (B) SD1 lysates were preincubated with various protease inhibitors prior to incubation with ASNase. ASNase cleavage is partially prevented by AEPi and by a PIC. Complete inhibition was achieved with a combination of AEPi and PIC. Combining either E64 or leupeptin, both components of PIC, with AEPi also prevents degradation. E64 and leupeptin both inhibit CTSB, and a combination of AEPi and CTSBi blocks cleavage of ASNase by SD1 cell lysate. Vertical line demarcates different gels; dashed vertical line indicates noncontiguous lanes within a gel. (C) CTSBi alone prevents ASNase cleavage by REH cell lysate.

Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts