Arsenic was a favorite poison in ancient Rome. It’s rumored to have caused the death of Napoleon, and a dose the size of a pea is enough to be fatal. Even exposure to small amounts of environmental arsenic can lead to cancer and other diseases over time.
So why would you want to put it in your body? Because arsenic is potent enough to kill cancer, but the trick is to get it to kill the cancer without hurting you. A new delivery method that conceals arsenic in a tiny droplet of fat may be able to do just that. The fat conceals the arsenic like a worm conceals a fishhook. Once the cancer tumor takes the bait, it’s toast.
Arsenic has been used as a cancer treatment before. Low doses of an arsenic compound are used to fight promyelocytic leukemia, a type of blood cancer. Arsenic can stop the growth of other cancers as well, but delivery methods are a challenge. Conventional drug delivery methods haven’t been effective.
Tom O’Halloran, a world-renowed chemist, is working on ways to deliver arsenic’s powerful punch to cancer cells without damaging healthy cells. “What limits arsenic’s broader application in cancer is its toxicity,” he says. “So, we asked whether we could control that toxicity but still allow its destructive effect to manifest only in cancer cells.”
O’Halloran and fellow researchers have found a way to put arsenic into a liposome, or a tiny droplet of fat smaller than the width of a hair. These droplets are called “nanobins.” The nanobins can be injected into the blood stream and will release their poisonous surprise when they reach cancer cells, but not before.
Cancer cells need to feed. They send out signals that tell blood vessels to form a network around them so that they have a source of nutrients and oxygen. These blood vessels are not as well-formed as others in the body, and have tiny gaps in their walls. These gaps are too small for blood cells, but not too small for a nanobin to slip through. Nanobins can travel through the body disguised as benign liposomes and then slip into the hungry cancer cells without causing suspicion.
The nanobins then collect in the tumor, and since the tumors are more acidic than the rest of the body, the fatty covering dissolves, releasing the arsenic from within the tumor’s own cells.
In animal studies, the nanobin injections have successfully killed breast, ovarian, and lung cancer cells. And the treatment is is “ferto-protective,” which means it will not damage fertility. If made viable for humans, this treatment could make a world of difference for women hoping to bear children after cancer treatment.
In an effort to make the cancer-killing nanobins even more attractive to cancer cells, O’Halloran and the team are now testing a method of attaching molecules to the surface of the nanobins—molecules that cancer cells need. These molecules work like a lure, except that the cancer cells do the reeling in. These molecule-topped nanobins may be especially helpful in fighting aggressive brain cancer.
O’Halloran and fellow researchers are hopeful about the future of the the arsenic-filled nanobins—the Trojan horse of cancer treatments.
“It’s abundantly clear that we need completely new methods to try to shut down cancer proliferation,” O’Halloran said. “We’re very excited that our work could pave the way for new types of treatments for brain, breast and other very resistant cancers.”
It would be amazing if arsenic, for centuries used as a poison, could be manipulated to kill cancer cells without hurting patients. We’re grateful for innovative science that brings us closer to a cure, and we’d love for this Trojan horse to be the treatment that gives cancer its final blow.
Keep fighting, friends!
Katie Taylor started writing in 5th grade and hasn't stopped since. Her favorite place to pen a phrase is in front of her fireplace with a cup of tea, but she's been known to write in parking lots on the backs of old receipts if necessary. She and her husband live cozily in the Pacific Northwest enjoying rainy days and Netflix.