INHIBITED GROWTH OF A RETICULUM-CELL SARCOMA (M5076) INDUCED INVITRO AND INVIVO BY MACROPHAGE-ACTIVATING AGENTS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 44  (6) , 2446-2451
Abstract
The tumor M5076 [mouse ovarian reticulum sarcoma] is highly malignant in vivo; however, in vitro M5076 tumor cells express many of the differentiated characteristics of an activated macrophage. This macrophage tumor (M5076) can be induced to cease cellular division following in vitro exposure to macrophage-activating agents, which was probably due to the induction of terminal differentiation. Not all macrophage-activating agents halt the proliferation of M5076 tumor cells in vitro, and evidence is presented that the treatment of mice, bearing M5076 tumor cells, with lipopolysaccharide is a highly effective therapeutic modality. Therapy protocols using multiple injections of lipopolysaccharide are capable of prolonging the survival and reducing the metastatic tumor burden of mice with a large tumor burden at the onset of therapy. This indicates that caution should be excercised in the use of M5076 tumors as a test model for chemotherapeutic agents, since the slightest contamination of an experimental drug with lipopolysaccharide would result in spurious positive results.