RESUMEN
Bacillus thuringiensis parasporin-2 (PS2Aa1 or Mpp46Aa1) selectively destroys human cancer cells, making it a promising anticancer agent. PS2Aa1 protoxin expression in Escherichia coli typically results in inclusion bodies that must be solubilized and digested by proteinase K to become active. Here, maltose-binding protein (MBP) was fused to the N-terminus of PS2Aa1, either full-length (MBP-fPS2) or truncated (MBP-tPS2), to increase soluble protein expression in E. coli and avoid solubilization and proteolytic activation. Soluble MBP-fPS2 and MBD-tPS2 proteins were produced in E. coli and purified with endotoxin levels below 1 EU/µg. MBP-fPS2 was cytotoxic against T cell leukemia MOLT-4 and Jurkat cell lines after proteinase-K digestion. However, MBP-tPS2 was cytotoxic immediately without MBP tag removal or activation. MBP-tPS2's thermal stability also makes it appropriate for bioproduction and therapeutic applications.
RESUMEN
Bacterial toxins have received a great deal of attention in the development of cancer treatments. Parasporin-2 (PS2Aa1 or Mpp46Aa1) is a Bacillus thuringiensis parasporal protein that preferentially destroys human cancer cells while not harming normal cells, making it a promising anticancer treatment. With the efficient development and sustainable silver nanoparticles (AgNPs) synthesis technology, the biomedical use of AgNPs has expanded. This study presents the development of a novel nanotoxin composed of biosynthesized silver nanoparticles loaded with the N-terminal truncated PS2Aa1 toxin. MOEAgNPs were synthesized using a biological method, with Moringa oleifera leaf extract and maltose serving as reducing and capping agents. The phytochemicals present in M. oleifera leaf extract were identified by GC-MS analysis. MOEAgNPs were loaded with N-terminal truncated PS2Aa1 fused with maltose-binding protein (MBP-tPS2) to formulate PS2-MOEAgNPs. The PS2-MOEAgNPs were evaluated for size, stability, toxin loading efficacy, and cytotoxicity. PS2-MOEAgNPs demonstrated dose-dependent cytotoxicity against the T-cell leukemia MOLT-4 and Jurkat cell lines but had little effect on the Hs68 fibroblast or normal cell line. Altogether, the current study provides robust evidence that PS2-MOEAgNPs can efficiently inhibit the proliferation of T-cell leukemia cells, thereby suggesting their potential as an alternative to traditional anticancer treatments.
Asunto(s)
Antineoplásicos , Nanopartículas del Metal , Plata , Humanos , Plata/química , Plata/farmacología , Nanopartículas del Metal/química , Antineoplásicos/farmacología , Antineoplásicos/química , Línea Celular Tumoral , Extractos Vegetales/química , Extractos Vegetales/farmacología , Moringa oleifera/química , Proteínas Recombinantes/farmacología , Hojas de la Planta/química , Supervivencia Celular/efectos de los fármacos , Endotoxinas , Proteínas de Unión a Maltosa/genética , Proteínas de Unión a Maltosa/metabolismoRESUMEN
In this study, we report the green synthesis of silver nanoparticles (AgNPs) from Morus alba or white mulberry leaf extract (MLE) and assess their antibacterial and anticancer potential. The GC-MS analysis of MLE confirmed the existence of phenolic compounds, serving as reducing, capping, and stabilizing agents in the biosynthesis of AgNPs. The MLE-AgNPs were spherical, with an average particle size of 20-44.5 nm and a face-centered cubic structure. EDX spectra confirmed the formation of AgNPs, and a negative zeta potential value (-14.5 mV) suggested their physicochemical stability. Excellent antibacterial activity was demonstrated by MLE-AgNPs against Acinetobacter baumannii strains with a MIC of 2 µg/mL, while good activity was observed against other Gram-negative (Escherichia coli and Salmonella typhimurium) and Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria with a MIC of 32 µg/mL. In vitro cytotoxic effects on MCF-7 (human breast cancer cells) and MCF-10A (normal human mammary epithelial cells) were investigated by the MTT assay. The half-maximal inhibitory concentrations (IC50) against MCF-7 cells were 18 and 33 µg/mL for MLE-AgNPs and MLE, respectively, with no effect on normal MCF-10A cells. Altogether, the results support the high antibacterial and anticancer potential of biosynthesized AgNPs by white mulberry leaf extract.
