Instituto de Biotecnología, Universidad del Papaloapan, Tuxtepec, Oaxaca 68301, Mexico.
División de Estudios de Posgrado, Universidad del Papaloapan, Tuxtepec, Oaxaca 68301, Mexico.
Toxins (Basel). 2021 Jul 9;13(7):476. doi: 10.3390/toxins13070476.
The protein A13-2 was obtained from strains isolated from the Papaloapan watershed region (Oaxaca, Mexico). The cytotoxic activity of parasporal inclusions was studied against breast cancer cell line (MCF-7) and normal cell (human peripheral blood mononuclear cells). The MTT, the formation of reactive species, nitric oxide, free cell DNA, and the type of death cellular were assessed. The protein A13-2 shows the highest cytotoxic activity against MCF-7 (13% cell viability at 6 µg/mL), the extracellular DNA increases, and it shows no stress for reactive species or nitric oxide. Besides, the A13-2 parasporin shows no toxicity to peripheral blood mononuclear cells, and it does not generate changes in nitric oxide levels or free cell DNA. Due to that, the cytotoxic effect of A13-2 was specific for MCF-7, and it does not affect normal cells. According to microscopy and flow cytometry, A13-2 parasporin leads to the death of MCF-7 cells by late apoptosis together with necrosis and without allowing the triggering of the survival mechanisms. When analyzed together, our results show for the first time that the A13-2 protein isolated from Mexican strains of preferentially kills MCF- 7 (cancer cells) over HEK 293 and PBMC cell lines (normal cells), thus representing a promising alternative for the treatment of cancer breast.
从墨西哥帕拉洛潘流域地区（瓦哈卡州）分离出的 菌株中获得了蛋白 A13-2。研究了伴胞晶体对乳腺癌细胞系（MCF-7）和正常细胞（人外周血单核细胞）的细胞毒性。评估了 MTT、活性物质形成、一氧化氮、游离细胞 DNA 和细胞死亡类型。蛋白 A13-2 对 MCF-7 的细胞毒性活性最高（在 6 µg/mL 时细胞活力为 13%），细胞外 DNA 增加，且对活性物质或一氧化氮没有压力。此外，A13-2 伴孢晶体对外周血单核细胞没有毒性，也不会引起一氧化氮水平或游离细胞 DNA 的变化。因此，A13-2 的细胞毒性作用对 MCF-7 具有特异性，而不会影响正常细胞。通过显微镜和流式细胞术分析，A13-2 伴孢晶体导致 MCF-7 细胞通过晚期细胞凋亡与坏死死亡，而不允许触发生存机制。综合分析，我们的结果首次表明，从墨西哥 菌株中分离出的 A13-2 蛋白优先杀死 MCF-7（癌细胞），而不是 HEK 293 和 PBMC 细胞系（正常细胞），因此代表了治疗乳腺癌的一种有前途的替代方法。
