Assesment of changes in the pattern of immune cell infi ltrate subpopulation in syngeneic MC38 colorectal cancer during course administration of glutamyltryptophan: an experimental study

Despite advances in gastric cancer screening and therapy, the search for effective methods for treating and preventing precancerous conditions, including chronic atrophic gastritis, remains an important challenge. Immunoprevention of cancer occupies a special place among strategies aimed at reducing the incidence of malignant neoplasms. The aim of this study was to assess changes in the subpopulation composition of the immune infiltrate in a syngeneic tumor model during course administration of glutamyl-tryptophan in mice. Materials and Methods. Tumor material was obtained from syngeneic MC38 colorectal cancer cells, transplanted intramammarily. Experimental animals received glutamyl-tryptophan (0.02 mg/kg), while control animals received saline. Repeated administrations were performed starting 14 days prior to tumor transplantation and continued until day 14 or day 21 after transplantation. Tumor growth kinetics and the subpopulation composition of the tumor immune infiltrate were assessed using flow cytometry. Results. Glutamyl-tryptophan administration did not affect tumor growth, but altered the cellular composition of the immune infiltrate at the second time point, manifested as a decrease in CD45 + cells, an increase in CD3 + cells, and a reduction in M2-like macrophages with high MHC expression. Analysis of DN-cell subpopulations at both time points demonstrated an increase in DN cells in both groups. In controls, DN NK + cells decreased twofold, whereas no such decrease was observed in the experimental group. Reduced levels of CD3 + CD8 + and NK1.1 + cells in both groups confirmed tumor progression. In contrast to the experimental group, the control group exhibited a pronounced decline in CD3 + , MHC II low CD206 + , and DN NK1.1 + cells, which may indicate a transition of the tumor microenvironment toward an immunosuppressive state. Conclusion. For the first time, changes in the composition of the immune infiltrate were evaluated in a model of a transplantable syngeneic tumor in immunocompetent animals treated with glutamyl-tryptophan. The study identified potential effector cell populations responsible for mediating immunosurveillance of tumor promotion and progression under in vivo experimental conditions.