A novel series of nitrofuran derivatives produces an anti‐tumor effect via a p53‐dependent mechanism

Abstract

Nitrofurantoin (NF) is an antibacterial that acts by inducing DNA damage. Increased selectivity towards bacterial DNA is conferred through the rapid activation by prokaryotic reductases. In cancer therapy, radiation and anti‐neoplastic drugs induce DNA damage to activate the p53‐dependent pathway, provoking apoptosis in cancer cells. In this study, a novel series of nitrofuran derivatives was designed with a presumed enhanced eukaryotic activity. The safety and the anti‐tumor efficacy of this series was assessed. Anticancer effects were assessed on colorectal cancer (Caco‐2), breast cancer (MCF‐7), cervical cancer (Hela), and liver cancer cells (HepG‐2). Cytotoxicity was estimated by MTT assays. Three compounds, NF‐5, NPO, and NS‐1 were shown to have the highest cytotoxic activity against cancer cells at IC50 values that are several‐fold lower that those observed for non‐malignant lung fibroblasts. The abilities to induce oxidative stress and apoptosis were tested by flow cytometry to measure dihydrodichlorofluorescein fluorescence and nuclear annexin‐V staining, and compared to that of NF and the reference chemotherapeutic drug (5‐FU). Other apoptosis markers measured include caspase3/7 activity and Bax/Bcl2 ratio. NF‐5, NPO, and NS‐1 induced oxidative DNA damage in cancer cells in vitro with subsequent cellular apoptosis. Furthermore, the three derivatives induced more than 50% increase in reactive oxygen species when compared to 5‐FU. Cells treated with these drugs showed an increased Bax/Bcl2 ratio and caspase 3/7 activity compared to the traditional chemotherapeutic drug. A positive linear correlation was shown between the oxidative load produced in the cells and the increase in apoptotic markers. Interestingly, despite equivalent induction of DNA damage demonstrated by similar pATM nuclear shuttling, NF‐5, NPO, and NS‐1 produced more cytotoxicity in MCF‐7 cells compared to the p53 mutant breast cancer cell line MDA‐MB‐231. Moreover, the effect of these derivatives on the p53 interaction with its negative modulator Murine Double Minute 2 (MDM2) was assessed using a multi‐spot sandwich ELISA kit. NF‐5, NPO, and NS‐1 promoted p53 release from MDM2 at concentrations that are 2–3 orders of magnitude lower than their cytotoxic IC50 values. These findings were further confirmed by in silico docking studies demonstrating possible binding sites on the protein. Further experiments are underway to assess the ability of lower, non‐cytotoxic concentrations of these drugs to improve the radio‐sensitivity of cancer cells via activation of p53‐dependnet pathways.Support or Funding InformationFunded by: AUB‐FM MPP grant #320148