A new study has reported that caffeic acid phenethyl ester (CAPE), a component of honey bee propolis, has powerful anti-breast cancer activities. Propolis is a sticky resinous material that bees manufacture from beeswax, tree resins and other substances. Propolis is used by bees as a sealant to repair small holes in their hives. Breast cancer patients frequently use alternative and natural remedies, and propolis is a naturopathic product used by some. CAPE is a major medicinal component of propolis.

In the study, CAPE was found to inhibit hormone receptor positive MCF-7 breast cancer cell growth, in a concentration dependent fashion, both in cell line and animal studies, without causing significant harm to normal mammary cells. Similar results were found for triple negative MDA-231 breast cancer cells. CAPE was also shown to strongly influence gene and protein expression, inducing cell cycle arrest, apoptosis (programmed cell death) and reduced expression of growth and transcription factors. Notably, CAPE was demonstrated to reduce the expression of multidrug resistance gene-1 (MDR-1), which is considered responsible for cancer cell resistance to chemotherapy. CAPE also appeared to have inhibitory effects on angiogenesis. The authors conclude that CAPE inhibits both hormone receptor positive and hormone receptor negative human breast cancer growth.

Study confirms previous findings regarding CAPE

The study expands on previous findings that CAPE interferes with breast cancer growth, including triple negative (ER-/PR-/HER2-) disease. However, safe and effective dosage of propolis has not been established. In fact, the chemical composition of propolis varies widely, depending on the geographical area from which it is sourced. Please see our article on honey for more information.