Lacticaseibacillus rhamnosus CRL1505 OR ITS CELL WALL ADMINISTERED AS IMMUNE ADJUVANTS IN A BREAST CANCER MODEL UNDER CHEMOTHERAPY.

GUTIERREZ, F. ; VASILE, B; IVIR, M.; DE MORENO DE LEBLANC, A.; ALVAREZ, S,; SALVA, S.

San Luis

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología; 2023

Sociedad Argentina de Inmunología

Lacticaseibacillus rhamnosus CRL1505 and its cell wall are able to enhancebasal myelopoiesis in cyclophosphamide (Cy)-affected bone marrow. The aim ofthis work was to study the immunomodulatory effect of the inmunobiotic L.rhamnosus CRL1505 and its postbiotic (cell wall) on basal myelopoiesisdeteriorated by chemotherapy treatment during a tumor process. In vitro, 4T1breast cancer cells were treated with Cy in the presence or absence of CRL1505postbiotic. Cell viability was evaluated by flow cytometry. In vivo, BALB/c micebearing breast cancer treated with Cy or not, were administered the CRL1505strain or its cell wall during 20 days. Tumor growth, bone marrow and blood cellcounts, lung histology and serum cytokines were evaluated. First, wedemonstrated that CRL1505 cell wall does not interfere with Cy toxicity in 4T1breast cancer cells. In addition, mice treated with Cy plus L. rhamnosus CRL1505showed a significant reduction in tumor size compared to the Cy control. Whilethe CRL1505 strain and its cell wall were effective treatments to reduceleukocyte, neutrophil and Px+ cell counts in peripheral blood, the immunobioticstrain was able to reduce the leukemoid reaction that accompanies the growth ofthis tumor. In the bone marrow, both oral supplements were able to increase theexpression of CXCR4 and TLR2. However, only the immunobiotic strain was ableto reduce granulocyte and macrophage progenitors. Finally, the CRL1505 strainand its postbiotic reduced splenomegaly, restored the myeloid/lymphoid ratio inthe spleen, and the monocyte population in the liver. Therefore, the oraladministration of L. rhamnosus CRL1505 or its cell wall exerts an adjuvant effecton chemotherapy treatment with cyclophosphamide in mice bearing breastcancer, observing the best benefits administering the viable bacteria, withoutproducing adverse effects.