A new study has reported that caffeine may reduce the effectiveness of anthracycline chemotherapy drugs such as doxorubicin (Adriamycin). The study was designed to investigate whether caffeine can interfere with intercalating chemotherapy drugs. Many anti-cancer drugs function by intercalating into DNA.
Intercalation occurs when a molecule of the right size and chemical attributes fits itself in between base pairs of DNA. The anthracycline chemotherapy drugs doxorubicin (Adriamycin), daunomycin (Cerubidine), and dactinomycin (Cosmegen) are intercalators that are used to inhibit DNA replication in rapidly growing cancer cells. Caffeine, a type of alkaloid, can also intercalate into DNA, as well as being able to form molecular complexes with some other alkaloids and anti-cancer drugs. Caffeine could interfere with an intercalating anti-tumor drug by forming molecular complexes with the drug, thereby blocking the chemotherapy drug from intercalating into the DNA. This would effectively reduce the toxicity of the drug to the cancer cells.

Study design and results

In the study, the authors tested the cytotoxic activities of several known DNA intercalators (doxorubicin, berberine, camptothecin, chelerythrine, ellipticine, and sanguinarine) on hormone receptor positive MCF-7 breast cancer cells, with and without the presence of caffeine. Caffeine was found to significantly reduce the cell killing actions of the intercalators.
The authors also performed other studies to examine the interaction of intercalating anti-cancer drugs with caffeine. Relatively strong interactions between caffeine and the intercalators were found, suggesting an “interceptor“ role of caffeine that would serve to protect the DNA from intercalation.
Please see our article on breast cancer diet during Adriamycin chemotherapy for more information on how to optimize treatment with Adriamycin and other anthracycline chemotherapy drugs.