Researchers have recently developed novel nanoparticles derived from maize that can target cancer cells directly, via an immune mechanism. The results of this study, published in Scientific Reports, are encouraging, and the technique has demonstrated efficacy in treating tumour-bearing laboratory mice with no adverse effects.
Nanoparticles, or particles whose size varies between 1 and 100nm, have shown tremendous potential in many areas of science and technology, including therapeutics. However, conventional, synthetic nanoparticles are complicated and expensive to produce and alternatives such as extracellular vesicles (EVs) have mass production challenges.
Another recently emerging option is that of plant-derived nanoparticles (NPs), which can be easily produced in high levels at relatively lower costs. Like EVs, these nanoparticle-based systems also contain bioactive molecules, including polyphenols (which are known antioxidants) and microRNA, and they can serve as vehicles for targeted drug delivery.
Recently, researchers from the Tokyo University of Science (TUS) developed anti-cancer bionanoparticles, using corn (maize) as the raw material.
Lead researcher Professor Makiya Nishikawa explained: “By controlling the physicochemical properties of nanoparticles, we can control their pharmacokinetics in the body; so, we wanted to explore the nanoparticulation of edible plants. Maize, or corn, is produced in large quantities worldwide in its native form as well as in its genetically modified forms. That is why we selected it for our study.”
The team centrifuged a super-sweet corn juice and then filtered it through a syringe filter with a 0.45μm pore size, then ultracentrifuged to obtain NPs derived from corn. The corn-derived NPs (cNPs) were approximately 80nm in diameter with a tiny net negative charge of -17mV.
The research team then set up experiments to see whether these cNPs were being taken up by various types of cells. In a series of promising results, the cNPs were taken up by multiple types of cells, including the clinically relevant colon26 tumor cells (cancer cells derived from mice), RAW264.7 macrophage-like cells, and normal NIH3T3 cells. RAW264.7 cells are commonly used as in vitro screens for immunomodulators.
The results were astounding: of the three types of cells, cNPs only significantly inhibited the growth of colon26 cells, indicating their selectivity for carcinogenic cell lines. Moreover, cNPs were able to successfully induce the release of tumour necrosis factor-α (TNF-α) from RAW264.7 cells. TNFα is primarily secreted by macrophages, natural killer cells, and lymphocytes, which help mount an anticancer response. “The strong TNFα response was encouraging and indicated the role of cNPs in treating various types of cancer,” explains Dr. Daisuke Sasaki, first author of the study and an instructor and researcher at TUS.
A luciferase-based assay revealed that the potent combination of cNPs and RAW264.7 cells significantly suppressed the proliferation of colon26 cells. Finally, the research team studied the effect of cNPs on laboratory mice bearing subcutaneous tumours. Once again, the results were astonishing: daily injections of cNPs into colon26 tumours significantly suppressed tumour growth, without causing serious side effects, or weight loss.
“By optimising nanoparticle properties and by combining them with anticancer drugs, we hope to devise safe and efficacious drugs for various cancers,” observed an optimistic Prof Nishikawa.
Source: Tokyo University of Science
