Affiliations: [a] Kyushu Institute of Technology (KIT), Iizuka, Fukuoka, Japan | [b] Department of Bioscience and Bioinfomatics, Kyushu Institute of Technology (KIT), Iizuka, Fukuoka, Japan
Abstract: BACKGROUND:Bacillus thuringiensis (Bt) is a Gram-positive bacterium that is known worldwide for its entomopathogenic properties. Recent studies indicate that bacteria produces protein inclusions called parasporins (PSs) that have anti-cancer activity against several types of tumor cells. OBJECTIVE:The present work aimed to select a Bt strain that produces an active PS against MCF-7 breast cancer cells, and to provide an initial quantification of its toxicity and protein concentration. METHODS:Two batches of Bt strains were fermented, and the parasporins were produced and isolated. In vitro tests were performed in 96-well plates and analyzed by a spectrophotometer. RESULTS:Most peptides did not have any cytopathic effect, but the A14d2 strain produces a PS with high toxicity to cancer cells. In the MTT test, the A14d2 strain PS was efficient with an LD50 of 14.83 μg/mL and a protein concentration of 520 μg/mL. At the end of the experiments, this PS was added to bacterial cells that produce other biologically active bacterial toxins against MCF-7 cells, which allowed it to be produced by a safe and inert microorganism to humans. CONCLUSION:PSs represent a potential tool to treat this form of breast cancer by providing peptides that may be useful in therapy.
Keywords: Bacterial toxin, anti-tumoral, breast tumor, cytotoxicity, biotherapy
DOI: 10.3233/BD-190405
Journal: Breast Disease, vol. 39, no. 1, pp. 37-42, 2020
