asialo-gm1-ganglioside and Hyperplasia

Weekly injections of dimethylhydrazine (DMH) (25 mg/kg), or azoxymethane (AOM) (8 mg/kg) to young adult male CDI mice for 1-2 months produced generalized intestinal crypt hyperplasia, which we measured in duodenum in terms of number of interphase and mitotic cells present in crypts. As shown earlier, the crypts expanded because of the presence of a hyperproliferative "initiated" crypt subpopulation which was also sensitive to natural killer (NK) cells. Hyperplasia was thus present as long as NK activity was suppressed by the carcinogen treatment. After interruption of the treatment for periods of 1, 2, 3, 6 and 10 months in the various groups, hyperplasia soon regressed as a result of elimination of the subpopulation by the recovering NK cells. When NK activity was once again eliminated during the terminal days of these "interruption periods" (by injections of anti-asialo GM-I antibody, alpha AGM-I), the original hyperplasia was fully reconstituted, apparently from stem cells of the subpopulation which survived up to 10 months in their crypt base location. These "initiated stem cells" represented, then, the original carcinogenic insult during the pre-cancerous period. They also appeared to be the source of the eventual neoplasia, as treating the animals with mutagens during the interruption periods produced specific changes in crypt base histology: new "crypt base basophilic" (CBB) cells appeared which produced large accumulations as well as microscopic tumors when NK activity was suppressed (by alpha AGM-I). Some of the initiated stem cells were apparently transformed into neoplastic ones which remained under NK control, the NK cells preventing the establishment of their progeny. Further experiments indicated that, although the initiated stem cells are not eliminated by normal NK activity, activated NK cells can kill them, thereby eliminating the potential source of neoplasia.

Topics: 1,2-Dimethylhydrazine; Animals; Azoxymethane; Brunner Glands; Cell Survival; Cell Transformation, Neoplastic; Dimethylhydrazines; Duodenal Neoplasms; G(M1) Ganglioside; Hyperplasia; Killer Cells, Natural; Male; Mice; Mice, Inbred Strains; Mitosis; Neoplastic Stem Cells; Poly I-C

The possible regulatory role of NK cells on early events in chemical carcinogenesis remains undefined. The present study examined whether NK cells control 1,2-dimethylhydrazine (DMH)-induced hyperplasia of the duodenal crypt in CD1 mice. Mice receiving chronic DMH treatment showed a dose-dependent hyperplasia confined to the proliferative zone, with a parallel increase in mitotic and 3H-TdR-labelled cells and significant suppression of splenic NK activity. Complete ablation of splenic NK activity with anti-asialo GM-I antibody (alpha AGM-I) treatment slightly enhanced hyperplasia. Halving of the DMH dose for 2 weeks led to regression of hyperplasia, which was totally prevented by alpha AGM-I treatment. The alpha AGM-I treatment alone did not influence crypt size in normal mice. Finally, a stimulation of NK activity with Poly I:C treatment in DMH-treated mice caused regression of the DMH-induced hyperplasia. Our results suggest that hyperplastic cells with possible genetic alterations induced by the carcinogen express target structures for NK cells, but that simultaneous carcinogen-induced suppression of NK activity hampers their containment, allowing progression of hyperplasia to neoplasia, possibly owing to additional genetic changes.

Topics: 1,2-Dimethylhydrazine; Animals; Carcinogens; Dimethylhydrazines; Dose-Response Relationship, Drug; Duodenal Neoplasms; Duodenum; G(M1) Ganglioside; Glycosphingolipids; Hyperplasia; Killer Cells, Natural; Male; Mice; Time Factors

Human recombinant interleukin-2 (rIL-2) was administered to normal and tumor-bearing BDF mice for 1 to 3 weeks, and the hematologic, clinical chemistry, gross and histopathologic findings were evaluated. Vascular leak syndrome (pulmonary edema, pleural effusion, ascites), hepatocyte necrosis, elevated hepatic serum transaminases, hypoalbuminemia, tissue and peripheral eosinophilia, thrombocytopenia, and prerenal azotemia were the detrimental effects of rIL-2 treatment. Vascular leak syndrome and hepatocyte necrosis were causally associated with vascular-oriented lymphocytic infiltration of pulmonary and hepatic parenchyma. Pleural effusions contained up to 99,000 cells/mm3, most of which were large granular lymphocytes. Antiserum to the glycolipid asialo GM1 (ganglio-n-tetrosylceramide), given simultaneously with rIL-2, prevented overt toxicity of rIL-2 (mortality, vascular leak syndrome, and hepatic damage) and substantially reduced infiltration of pulmonary and hepatic vasculature by asialo GM1+ lymphocytes. Asialo GM1 antiserum did not inhibit lymphoid hyperplasia, tissue infiltration by Lyt 2+ lymphocytes, tissue and peripheral eosinophilia, or thrombocytopenia in rIL-2 treated mice. Additionally, asialo GM1 antisera prevented toxicity, but not anti-tumor efficacy, of high dose rIL-2 therapy in BDF mice bearing the colon 38 adenocarcinoma. These results suggest that, in BDF mice and with this tumor model, vascular leak syndrome and hepatocyte necrosis are mediated by an endogenous subset of rIL-2-stimulated lymphocytes which are asialo GM positive, that mechanisms of toxicity and efficacy associated with high dose rIL-2 therapy are not necessarily the same, and that these mechanisms can be therapeutically separated.

Topics: Adenocarcinoma; Animals; Antibodies, Monoclonal; Capillary Permeability; Colonic Neoplasms; G(M1) Ganglioside; Glycosphingolipids; Hyperplasia; Immunotherapy; Interleukin-2; Killer Cells, Natural; Liver Diseases; Lymphocyte Activation; Lymphocytes; Mice; Pleural Effusion; Pulmonary Edema; Recombinant Proteins; Spleen