Abstract
Ciprofloxacin is a widely used fluoroquinolone antibiotic whose biological effects extend beyond bacterial DNA gyrase and topoisomerase IV inhibition. Accumulating preclinical evidence suggests that ciprofloxacin can modulate mammalian cellular pathways involved in tumor growth, regulated cell death, inflammation, and tissue homeostasis. This narrative review summarizes PubMed-indexed evidence on the pharmacological effects of ciprofloxacin beyond antibacterial activity, focusing on DNA and topoisomerase-related mechanisms, mitochondrial dysfunction, apoptosis, cell-cycle regulation, oxidative stress, ferroptosis, autophagy, inflammatory signaling, and tissue remodeling. Evidence concerning the parent ciprofloxacin molecule is considered separately from that involving chemical derivatives, conjugates, nanoparticles, and combination regimens. Overall, the available evidence suggests that the effects of ciprofloxacin on cancer cells and host pathways are context-dependent. However, most of the evidence remains preclinical, and the clinical relevance of concentrations used in many studies remains uncertain. Established fluoroquinolone-associated toxicities should also be considered when evaluating its potential for drug repurposing. Ciprofloxacin may therefore warrant further pharmacological investigation, but it should not yet be considered an established anticancer or host-directed therapy.