Despite numerous research efforts and several effective vaccines and therapies developed against COronaVIrus Disease 2019 (COVID-19), drug repurposing remains an attractive alternative to identify new treatments for SARS-CoV-2 virus variants and other viral infections that may emerge in the future. Cellular polyamines support viral propagation and tumor growth. Here we tested the antiviral activity of an irreversible inhibitor of polyamine biosynthesis, α-difluoromethylornithine (DFMO) and a non-steroidal anti-inflammatory drug (NSAID) Sulindac, which have been previously evaluated for colon cancer chemoprevention. The drugs were tested as single agents and in combination in human Calu-3 lung adenocarcinoma and Caco-2 colon adenocarcinoma cell lines and the