Caring Currents

"Trojan Horse" Chemotherapy the Cancer Treatment of the Future?

Last updated: Jul 03, 2009

Trojan Horse
Image by Darcy McCarty used under the creative commons attribution license.

This week health news experts were all agog over an Australian study that unveiled a treatment using tiny cells that perform like a "Trojan horse," sneaking chemotherapy agents into cancer cells.

Given that it was a preliminary study performed in mice, why is this news so exciting? The study points the way to a new approach to cancer treatment, one that could eradicate 100 percent of cancer cells and leave cancer patients much less injured by the side effects of chemotherapy treatment.

Here's the central issue: In killing off cancer cells, chemotherapy also injures healthy cells. It's a "one size fits all" treatment; toxic chemotherapy agents cut a swath across the entire body and all body systems. And even so, a small percentage of the cancer cells produce proteins that make them resistant to the chemo; these cells remain in the body and eventually proliferate, causing a recurrence.

Researchers have long recognized that treatments that can eliminate all cancerous cells without injuring healthy cells is the goal in cancer treatment. The Australian researchers, Jennifer MacDiarmid and Himanshu Brahmbhatt, showed that cellular "Trojan horses" could be slipped into cancer cells while carrying chemotherapy agents that could then kill off the cells -- without injuring surrounding cells.

This is actually just one of many approaches being pioneered around the world using RNI interference, or RNAi, a technology considered so promising it won the Nobel prize for medicine in 2006. RNAi basically selectively shuts off genes responsible for producing proteins that feed tumor growth. But so far practical approaches using RNAi have been harder to come by than researchers originally hoped.

Sydney-based EnGeneIC, MacDiarmid and Brahmbhatt's company, is using a two-step approach; tiny cells use RNAi to switch off protein production; then a second wave of nano-sized cells known as EDVs enter the cells and release chemotherapy agents, killing the host cell. In the study, published in Nature Biotechnology, 100 percent of aggressive uterine tumors that had been implanted into mice were eliminated. A corresponding group of mice, also implanted with tumors that were left untreated, all died within a month. The researchers also announced that they'd been using the treatment on 20 dogs with brain tumors and achieved similar results.

Cancer experts were excited but cautious, because the therapy still has to be tested in humans, and many cancer treatments that work for mice and other animals don't turn out to work on people. They plan to start human clinical trials in the next few months, and if you or a loved one might be a candidate for a last-ditch option, this one might be worth considering.

Meanwhile, there are dozens more teams working on RNAi therapies around the world, many of whom have reported promising results but haven't published official reports of treatment outcomes yet. This is definitely one of the research areas in which a true cancer treatment breakthrough could occur. As they used to say, watch this space.