Crotoxin Modulates Macrophage Phenotypic Reprogramming.

Area of Science:

• Immunology
• Pharmacology
• Cancer Biology

Background:

• Macrophage plasticity is crucial for effective immune responses against pathogens and environmental changes.
• Crotoxin (CTX), a major component of Crotalus durissus terrificus venom, exhibits known antitumor properties in preclinical and clinical settings.
• Understanding CTX's impact on macrophage phenotype is key to exploring its therapeutic potential.

Purpose of the Study:

• To investigate the effect of CTX on macrophage phenotypic reprogramming within a mesenchymal tumor microenvironment.
• To analyze CTX's influence on macrophages from healthy animals' peritoneal cavity.
• To determine if CTX administration modulates macrophage phenotype and nitric oxide (NO•) production.

Main Methods:

• Ehrlich Ascitic Tumor (EAT) cells were inoculated intraperitoneally in mice.
• CTX was administered subcutaneously at doses of 0.9 or 5 μg/animal.
• Macrophage phenotypes (M1/M2) and NO• production were assessed in ascites and peritoneal cells after 13 days.

Main Results:

• In tumor-bearing mice, CTX (0.9 or 5 μg/animal) modulated macrophages towards an M1 phenotype, increasing NO• production in ascites.
• In healthy mice, CTX induced dose-dependent macrophage polarization: M1 at 0.9 μg/animal and M2 at 5.0 μg/animal.
• Increased NO• production was observed in peritoneal macrophages only at the 0.9 μg/animal CTX dose in healthy animals.

Conclusions:

• A single CTX administration significantly impacts macrophage phenotypic reprogramming and the secretory status of ascites cells.
• CTX influences key events in mesenchymal tumor progression by altering the tumor microenvironment.
• These findings suggest CTX as a potential agent for developing novel therapeutic strategies targeting immune dysregulation in cancer.