Asparagine synthetase is partially localized to the plasma membrane and upregulated by L-asparaginase in U937 cells

J Huazhong Univ Sci Technolog Med Sci. 2011 Apr;31(2):159-163. doi: 10.1007/s11596-011-0243-4. Epub 2011 Apr 20.

Abstract

This study investigated the intracellular localization of asparagine synthetase (ASNS) in the relation with chemoresistance in leukemia. pIRES-GFP-ASNS-Flag/Neo expression vector was transiently tansfected into SK-N-MC cells and 297T cells respectively. Immunofluorescence and Western blot analysis were performed for cellular localization of ASNS respectively. U937 cells were treated with L-asparaginase for 48 h and examined for endogenous ASNS expression on plasma membrane by immunofluorescence staining. Immunofluorescence staining showed that the transiently expressed ASNS was partly localized on transfected-SK-N-MC cell surface. Moreover, Western blotting exhibited that ASNS expressed both in cytosol and on plasma membrane of transfected-293T cells. Immunofluorescence staining with anti-ASNS-specific monoclonal antibody revealed that endogenous ASNS was localized on the plasma membrane of U937 cells, except for its distribution in the cytosol. In addition, ASNS exhibited a higher expression on plasma membrane after treatment with L-asparaginase as compared with the untreated cells. It was concluded that the subcellular translocation of ASNS may play an important role in L-asparaginase resistance in leukemia cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Asparaginase / pharmacology*
  • Aspartate-Ammonia Ligase / metabolism*
  • Cell Membrane / enzymology
  • Drug Resistance, Neoplasm / drug effects*
  • Humans
  • Transfection
  • U937 Cells

Substances

  • Antineoplastic Agents
  • Asparaginase
  • Aspartate-Ammonia Ligase