Ameliorated in vitro anti-cancer efficacy of methotrexate loaded zinc oxide nanoparticles in breast cancer cell lines MCF-7 & MDA-MB-231 and its acute toxicity study

Abstract Traditional therapies often struggle with specificity and resistance in case of cancer treatments. It is therefore important to investigate new approaches for cancer treatment based on nanotechnology. Zinc oxide nanoparticles (ZnONPs) are known to exhibit anti-cancer properties by inducing oxidative stress, apoptosis, and cell cycle arrest. Methotrexate (MTX) a known anti-folate shows specificity to folate receptors and interrupts healthy functioning of cells. This study proposes the use of previously characterized biocompatible Methotrexate loaded Zinc oxide nanoparticles (MTX-ZnONPs) as a dual action therapeutic strategy against breast cancer cell lines, MCF-7 (MTX-sensitive) and MDA-MB-231 (MTX-resistant). To elucidate the cytotoxicity mechanism of MTX-ZnONPs an in depth In vitro study was carried out. In vitro assays, including cell cycle analysis, apoptosis assay, and western blot analysis to study the protein expression were performed. Results of these assays, further supported the anti-cancer activity of MTX-ZnONPs showing apoptotic and necrotic activity in MCF-7 and MDA-MB-231 cell line respectively. In vivo acute oral toxicity study to identify the LD 50 in animals revealed no signs of toxicity and mortality up to 550 mg kg −1 body weight of animal, significantly higher LD 50 values than anticipated therapeutic levels and safety of the synthesized nanosystem. The study concludes that MTX-ZnONPs exhibit anti-cancer potential against breast cancer cells offering a promising strategy for overcoming resistance.