Cytotoxic Potential from the Extracellular Filtrate from Aspergillus niveus Cultured in YPD Medium against Human Tumor Cells

Different fungal species, especially from the genus Aspergillus, have been reported as producers of small molecules, including proteins, with biological activity and a better understanding of their sources, structure, function and toxicity is essential for their biotechnological applications. According to this, our aim was to evaluate the cytotoxic activity of the extracellular filtrate produced by A. niveus. The crude filtrate obtained in YPD medium containing 18 kDa protein, after cultivation for 120 h, was selected for cytotoxic assay, assessed by Giemsa staining, against different human tumor cell lines. Crude filtrate inhibited (from 27% to 50%) the ONS-76 (medulloblastoma), HT144T (melanoma), HOS (osteosarcoma), T98G (glioblastoma) human tumor cell lines and MRC-5 (fibroblasts) human normal cells, at 20 µg/mL for 72 h treatment. According to this, the 18 kDa protein band and the fractions obtained after DEAE-Cellulose procedure were evaluated through mass spectrometry (MS/MS) analysis, revealing the presence of peptides with similarity to the alpha-sarcin, mitogillin and Aspf1 ribotoxins described for other Aspergillus species. In conclusion, the A. niveus extracellular filtrate containing ribotoxin-like proteins reduced, in vitro, the growth of human tumor cell lines indicating their biotechnological potential, indicating a possible future application in the elaboration of immunotoxins.