Researchers have found a cancer-killing powerhouse in the most unlikely of places – honeybee venom. In a fascinating new study published in Nature Precision Oncology, the venom was found to kill cancer cells while leaving normal cells relatively unscathed in vitro and in mouse models.
Even more impressively, when the active ingredient (a compound called melittin) was isolated and administered together with chemotherapy drugs to mouse models, the combination was extremely effective at suppressing cancer growth. The team believes the findings could be crucial to combatting a notoriously aggressive and hard-to-treat breast cancer types that respond poorly to current treatments.
The venom is extremely successful at selectively targeting HER2-positive cancer cells, a form of breast cancer that has high levels of human epidermal growth factor 2 (HER2) that promotes cancer growth. HER2-positive breast cancer does respond to available drugs that target HER2, but are highly aggressive and grow rapidly.
“No-one had previously compared the effects of honeybee venom or melittin across all of the different subtypes of breast cancer and normal cells," lead author Dr Ciara Duffy from the Harry Perkins Institute of Medical Research said in a statement. “We found both honeybee venom and melittin significantly, selectively and rapidly reduced the viability of triple-negative breast cancer and HER2-enriched breast cancer cells."
Approximately 10-20 percent of all breast cancers do not respond to any hormonal therapy currently in use. These cases, called triple-negative breast cancers, are extremely difficult to treat and prognoses are usually much poorer, with the cancer usually more likely to both spread and recur than other forms of breast cancer. Researchers have been desperately attempting to find therapies that can combat triple-negative cancers, but answers have eluded them.
The team discovered that melittin could be a powerful weapon against both triple-negative and HER2-positive breast cancer, and even managed to engineer the compound to have more effective targeting towards cancer cells.
“Melittin modulated the signaling in breast cancer cells by suppressing the activation of the receptor that is commonly overexpressed in triple-negative breast cancer, the epidermal growth factor receptor, and it suppressed the activation of HER2 which is over-expressed in HER2-enriched breast cancer,” Dr Duffy said.
In a two-pronged attack on cancerous cells, the venom demonstrated an impressive ability to selectively kill HER2-positive and triple-negative cancer cells. By interfering with cell-surface receptors, the venom inhibits pathways that lead to cell overgrowth and reproduction in cancer. Alongside this, Dr. Duffy also reports a pore-forming action, in which the venom creates tiny holes in the cell membrane and induces cell death.
The team believes the use of honeybee products, called apitherapy, has the potential to "impact the economic aspects of cancer research globally" and suggest further investigation. It is still extremely early days for the venom-based research and the results, which are only on mouse models and isolated cell lines, require more testing before any potential applications in therapy. However, it will certainly be extremely interesting to follow any further developments of apitherapy in the fight against breast cancer, and whether such an unsuspecting insect as the honeybee holds the key.