Urban legend has it that the cure for cancer is probably buried in the root of some obscure plant in the middle of the Amazon rainforest, and we just haven’t found it yet. While that’s overstating what any one medicine can do to fight what’s actually hundreds of different diseases, that doesn’t mean natural remedies don’t offer some valuable tools in the fight against cancer. Last year Richard Jones from the Ben May Department for Cancer Research found that a compound in beehives could be used to treat prostate cancer. Now, one of his colleagues has shown that an extract from a cousin of ginseng can kill colon cancer cells without affecting the normal cells around them.

Wei Du, PhD, studies ways to develop more targeted treatments for cancer by analyzing the genetic profile of cancer cells and tumors to find mutations that can be exploited for therapy. In a recent study published in Cell Death and Disease, he worked with Chun-Su Yuan, MD, PhD, from the Tang Center for Herbal Medicine Research to examine the effects a compound called falcarindiol has on colorectal cancer cells.

Falcarindiol is an extract from a plant called Oplopanax horridus, or devil’s club, which is related to ginseng. While it sounds like something from a Harry Potter book, it’s not the mythical cancer-curing plant from the rainforest; it’s actually a shrub that grows in the Pacific Northwest, western Canada and Alaska. It’s known to have anti-inflammatory and antibacterial properties, and is also found in small amounts in carrots, which may protect them from fungus. But most interesting are its anti-cancer effects.

Du and Yuan tested it on human colorectal cancer cells and found that it was able to kill the cancer cells while preserving the normal colon epithelial cells around them. It did so by inducing a process called endoplasmic reticulum (ER) stress. The endoplasmic reticulum is a cell site involved in folding proteins for use by the cells. When proteins are misfolded, they build up as waste. If too much of this waste builds up it becomes toxic to the cell and triggers apoptosis, or cell death.

ER stress interferes with the cell’s ability to rid itself of these proteins. Du and Yuan found that falcarindiol acts on certain genes that regulate ER stress and trigger the chain of events that leads to cells destroying themselves. Because cancer cells are much more active and produce proteins more rapidly than normal cells, they’re more susceptible to this reaction. Just the right dose of falcarindiol can trigger ER stress and subsequent cell death in the rambunctious cancer cells while sparing the well-behaved normal ones. Du said this opens up possibilities for more precise targeting of cancer cells that are susceptible to ER stress.

“It has a lot of potential uses. For example it can be used together with chemotherapeutic drugs currently used in clinics, as a way to enhance the toxicity to cancer cells and reduce the side effects,” he said. “Even though this may not have as strong an effect as synthesized drugs because it’s a natural compound, it could be better because of its lower toxicity to normal cells.”

And knowing the mechanism it uses to kill cancer cells means falcarindiol and compounds like it might also be useful to other highly active types of cancer. Maybe it’s not as romantic as some unknown miracle plant unearthed from the depths of the jungle, but a shrub from Oregon could be a pretty useful tool for fighting cancer.

=====
Jin HR, Zhao J, Zhang Z, Liao Y, Wang CZ, Huang WH, Li SP, He TC, Yuan CS, & Du W (2012). The antitumor natural compound falcarindiol promotes cancer cell death by inducing endoplasmic reticulum stress. Cell death & disease, 3 PMID: 22914324