Cytotoxic Effects of Loperamide Hydrochloride on Canine Cancer Cells

Loperamide is a peripheralopiate agonist that can cause apoptosis and G2/M arrest in human cancer cell lines and maysensitize cells to chemotherapy. The objectives of this study were to investigate theeffects of loperamide on viability, apoptosis and cell cycle kinetics in canine cancercells and to establish whether the drug sensitizes cells to doxorubicin. Cell viabilitywas assessed using Alamar Blue. Cell death and cell cycle were studied using flowcytometry with 7-Aminoactinomycin-D (7-AAD) and propidium iodide (PI), respectively.Loperamide decreased cell viability in a dose-dependent fashion and was most effectiveagainst canine osteosarcoma cells. In all cell lines, it induced a dose and time dependentapoptosis and resulted in accumulation in G0/G1. When co-incubated with doxorubicin,loperamide induced a synergistic cell kill in canine carcinoma cells. Investigation iswarranted into the role of loperamide in the treatment of canine cancer.