Antitumor reactivity induced by liposomal MTP-PE in a liver metastasis model of colon cancer in the rat

K THOMAS*, AM NIJENHUIS, Bert H.J. DONTJE, T DAEMEN, GL SCHERPHOF

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    9 Citations (Scopus)

    Abstract

    The antitumor effects of muramyl tripeptide phosphatidylethanolamine, incorporated within the lipophilic phase of liposomes (lipMTP-PE) were studied using a model of liver metastasis of colon cancer in the rat. Intravenous immunotherapy with lipMTP-PE, when started 2 days before the inoculation of tumor cells and given twice a week, significantly reduced subsequent tumor growth in the liver, The main effect of treatment appeared to be a substantial local increase in the number of tumoricidal macrophages and lymphocytes. Tumor cell lysis by isolated macrophages in vitro, however, appeared not to be elevated above the level triggered by tumor growth alone. Therefore, the observed therapeutic effect of lipMTP-PE probably results from a combination of (1) an increase in the number of cytotoxic macrophages at the onset of metastatic growth in the liver, thus increasing the probability of lethal contacts between tumoricidal effecters and tumor cells and (2) indirect effects of lipMTP-PE, via the induction of cytokine production by liver macrophages, leading to increased numbers and/or activity of cytotoxic lymphocytes and natural killer cells.

    Original languageEnglish
    Pages (from-to)328-336
    Number of pages9
    JournalClinical & Experimental Metastasis
    Volume13
    Issue number5
    DOIs
    Publication statusPublished - Sept-1995

    Keywords

    • COLON ADENOCARCINOMA
    • (CYTOTOXIC) LYMPHOCYTES
    • LIPOSOMAL MTP-PE
    • LIVER MACROPHAGES
    • METASTASIS
    • TUMORICIDAL ACTIVITY
    • LIPOPHILIC MURAMYL DIPEPTIDE
    • TUMOR-GROWTH
    • TRIPEPTIDE PHOSPHATIDYLETHANOLAMINE
    • PHASE-II
    • LIPID-A
    • MACROPHAGES
    • ACTIVATION
    • THERAPY
    • CELLS

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