“ Ascorbic acid (AA) significantly enhances topotecan cytotoxicity in MCF‐7 tumor cells.”
“Synergistic cytotoxicity of topotecan and AA may result from increased DNA damage.”
“The presence of ascorbic acid also increased both topoisomerase I‐dependent topotecan‐… cleavage complex formation and topotecan‐induced DNA double‐strand breaks, suggesting that ascorbic acid participated in enhancing … damage induced by topotecan and that the enhanced DNA damage is responsible … the synergistic interactions of topotecan and ascorbic acid.”