Quercetin against MCF7 and CAL51 breast cancer cell lines: apoptosis, gene expression and cytotoxicity of nano-quercetin

Aims: To evaluate the anti breast-cancer activity, biocompatibility and toxicity of poly(d,l)-lactic-co-glycolic acid (PLGA)-encapsulated quercetin nanoparticles (Q-PLGA-NPs). Materials & methods: Quercetin was nano-encapsulated by an emulsion-diffusion process, and the nanoparticles were fully characterized through Fourier transform infrared spectroscopy, x-ray diffractions, FESEM and zeta-sizer analysis. Activity against CAL51 and MCF7 cell lines were assessed by DNA fragmentation assays, fluorescence microscopy, and acridine-orange, and propidium-iodide double-stainings. Biocompatibility towards red blood cells and toxicity towards mice were also explored. Results: The Q-PLGA-NPs exhibited apoptotic activity against the cell lines. The murine in vivo studies showed no significant alterations in the liver and kidney's functional biomarkers, and no apparent abnormalities, or tissue damages were observed in the histological images of the liver, spleen, lungs, heart and kidneys. Conclusion: The study established the preliminary in vitro efficacy and in vivo safety of Q-PLGA-NPs as a potential anti-breast cancer formulation.Lay abstract Quercetin is a flavonoid, a type of chemical, antioxidant in nature, found in many fruits and vegetables. It is known to have anticancer properties. In this study, quercetin was encased into nano-sized particles of biologically compatible and bio-degradable synthetic polymer, named PLGA (poly-[D,L]-lactic-co-glycolic acid). The effects of the quercetin nanoparticles/nano-quercetin were tested against two types of breast cancer cell lines in the laboratory. The quercetin-loaded nanoparticles were able to kill the breast cancer cells, suggesting they could be able to kill the cancer cells in the body. Also, when given to mice, the quercetin nanoparticles did not appear to damage any organ, or change the functions of the liver, and kidneys, thereby suggesting that they are not toxic. Further work is required to assess how well they could be used to treat breast cancer in people.