9‐nitro‐camptothecin delays growth of U‐937 leukemia tumors in nude mice and is cytotoxic or cytostatic for human myelomonocytic leukemia lines in vitro Academic Article uri icon


MeSH Major

  • B-Lymphocytes
  • Basic-Leucine Zipper Transcription Factors
  • Germinal Center
  • Immunologic Memory
  • T-Lymphocytes, Helper-Inducer


  • The camptothecin derivatives 9-nitro-camptothecin (9NC) and 9-amino-camptothecin (9AC) inhibit similarly growth of HL-60, KG-1, and U-937 cells in vitro, whereas growth of THP-1 cells is inhibited by 9AC, but not by 9NC. Growth inhibition is accompanied by enlargement of cells which contain one (HL-60, THP-1) or more (KG-1, U-937) nuclei. Flow cytometry studies showed that 9NC-treated HL-60 and U-937 cells accumulate in the S and G2 phases of the cell cycle; then they die by apoptosis, with the HL-60 cells being more sensitive than U-937 cells to 9NC. In contrast, 9NC-treated KG-1 and THP-1 cells accumulate in S and G2 phases, but resist death by apoptosis. Of the cell lines tested, only U-937 cells xenografted in nude mice generated subcutaneous myeloid tumors, which exhibited a delayed growth in the presence of 9NC. Further, 9NC-treated advanced U-937 tumors regressed temporarily, indicating that U-937 cells consist of 9NC-sensitive and 9NC-resistant populations.

publication date

  • January 1993



  • Academic Article


Digital Object Identifier (DOI)

  • 10.1111/j.1600-0609.1993.tb00146.x

Additional Document Info

start page

  • 81

end page

  • 9


  • 50


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