Potentiating effect of methyl methane sulfonate on Friend virus leukemogenesis in vivo

Prevention of oncogenic viral infections in mice with CGP 11637, a synthetic muramyl dipeptide analog

The efficacy of N-acetyl-nor-muramyl-L-alanyl-D-isoglutamine (nor-MDP) in controlling viral oncogenesis in mice was investigated. The tumors studied were blood cell malignancies induced by Friend leukemia virus in SJL/J mice, spontaneous mammary neoplasms in RIII/Imr and C3H/OuJ mice, and spontaneous lymphocytic leukemia in AKR/J mice. A transplantable tumor, Lewis lung carcinoma, in C57BL/6J mice was used as a nonvirally induced control model. The nor-MDP was dissolved in saline and made into an emulsion with an equal volume of squalene-Arlacel A and injected subcutaneously at 1- to 2-month intervals. Test and control mice were challenged with exogenous virus or tumor transplant 2 weeks after a second injection of nor-MDP. Administration was started at around 2 months of age in mice that develop spontaneous neoplasms. Electron microscopy studies were done on neoplastic tissues of selected test and control mice. This administration of nor-MDP prevented erythroleukemia in SJL/J mice caused by low doses of Friend leukemia virus (although erythroleukemia survivors were not protected from a late-developing lymphoma) and also delayed (possibly prevented) the development of a spontaneous mammary neoplasm in RIII/Imr mice. No antitumor effects were observed on the spontaneous neoplasms of C3H/OuJ and AKR/J mice or on the Lewis lung carcinoma implanted into C57BL/6J mice. Electron microscopic examinations of the various neoplastic tissues indicated that nor-MDP administration eliminated or reduced extracellular viruses. The results suggested that under the experimental conditions used nor-MDP appears to effect the viruses and not the malignant cells per se.

Effect of propane sultone pretreatment on Friend virus leukemogenesis in mice

Propane sultone (PS) injected i.p. 24 or more hours before Friend leukemia virus increased the incidence of lymphoma in SJL/J mice and at a higher dose increased the incidence of erythroleukemia in B10SJF1 mice. PS at the same time also decreased hematopoietic stem cell clonogenicity.