Investigação do potencial efeito antitumoral e anticaquético da alamandina em modelo de melanoma murino

Abstract

Skin cancer is one of the most common malignancies, accounting for 30% of all cancers registered in the country. The melanoma, although less frequent, is the most aggressive, with a high possibility of metastasis and complications such as cancer-associated cachexia. Cancer-associated cachexia leads to severe muscle wasting and adipose tissue depletion in nearly half of cancer patients. The Renin Angiotensin System (RAS) implication in the development of cancer and in the pathophysiology of cachexia has already been described. The heptapeptide angiotensin-(1-7) was investigated for its antitumor and anti-cachetic effect by activating its receptor (Mas) and in our group; we have just described the in vitro antiproliferative effect of another RAS peptide, Alamandine. Our aim was to evaluate the participation of Alamandine in the process of tumorigenesis and development of cachexia in a melanoma model using C57BL6/J mice (CEUA: 198/2018). Methods: Mice were inoculated with B16F10 cells and after palpable tumor formation, they were randomized into groups for gavage oral treatment: HPβCD 82μg/Kg/day or alamandine 30, 50 and 100μg/Kg/day. Body weight and tumor volume variation were evaluated during fourteen days of treatment and after animals euthanasia, tissues were collected for analysis. Statistical analyzes were performed using GraphPad Prism 8, with Student's t test for independent samples or ANOVA. Results: A significant reduction in tumor mass was observed (HPβCD 2.015±0.6376g Ala30μg/Kg/day 1.776±0.5584g Ala50μg/Kg/day 0.6730±0.4722g and Ala100μg/Kg/day 2.595±0.2317g) and volume (HPβCD 585.27±261.37mm3; Ala30μg 395.16±206.67mm3; Ala50μg 297.03±122.87mm3; Ala100μg 596.27±396.88mm3) after fourteen days of treatment with alamandine compared to tumor-bearing animals receiving only empty cyclodextrin. The body mass of the animals was preserved by treatment with alamandine, with intense weight loss in the non-treated group (CT 10.03±3.222%; HPβCD -4.073±2.127%; Ala30μg 0.1880±2.980%; Ala50μg 4.744± 6.063%; Ala100μg 5.946±6.934%). In addition, the loss of muscle mass observed in animals receiving only cyclodextrin was partially reversed by alamandine (measured by the percentage of muscle or fat mass compared to the initial body mass): gastrocnemius (CT 0.60±0.026%; HPβCD 0.46±0.018%; Ala30μg 0.049±0.038%; Ala50μg 0.5720± 0.04877%; Ala100μg 0.5537± 0.07114%); anterior tibial (CT 0.164± 0.00958%; HPβCD 0.148± 0.148%; Ala30μg 0.149±0.0208%; Ala50μg 0.203±0.0274%; Ala100μg 0.164±0.0168%); soleus (CT 0.02220±0.04245%; HPβCD 0.01197±0.02337%; Ala30μg 0.01868±0.02716%; Ala50μg 0.02461±0.03107%; Ala100μg 0.01580±0.02402 %) and epididymal fat (CT 1.01±0.165%; HPβCD 0.208±0.181%; Ala30μg 0.795±0.349%; Ala50μg 0.792±0.225%; Ala100μg 0.590±0.0886%). Conclusions: Our data suggest that the cyclodextrin formulation containing alamandine has an antitumor and anticachectic effect in a murine melanoma model with B16F10 cells.