Imagine these headlines in medical news: “Anthrax cures cancer!” A team of researchers from the National Cancer Institute and the National Institutes of Health, both in Maryland, claim just that. Led by Dr. Han-Mo Koo, the team has identified a mechanism in mammalian cells that could be used to fight cancer. A protein called mitogen-activated protein kinase, or MAPK, helps regulate growth in normal cells. In cancer cells, MAPK is often mutated, and cancer cells grow and divide uncontrollably, producing a tumour.
The toxic chemical produced by anthrax is what makes the bacteria so deadly. Anthrax toxin consists of three components that although harmless when separate, can combine to form a deadly poison. This toxin seeps into the circulatory system, causing blood cells to rupture, die, and congest the blood stream, causing septic shock. The most toxic of these three components, called Lethal Factor, targets MAPK. In healthy cells, Lethal Factor grabs onto MAPK by means of a long groove. It chews off one end of the MAPK protein, disables it, and kills the cell.
Dr. Koo and his research team “…hypothesized that the same mechanism would kill a cancer cell by inhibiting the MAPK pathway. We have obtained identical results from [test tube] experiments and from living tissue…in test tubes or in mice, cancerous cells were transformed into a precancerous state with the application of LeTx [Lethal Factor]. Tumours simply shrank.” Dark-coloured dead skin emerged, confirming tumour cell death.
Dr. Koo and his researchers conclude that LeTx could potentially cure some forms of cancer. At the very least, they claim, LeTx can inhibit tumour growth. Koo’s groundbreaking work represents new frontiers for cancer research. Within 24 hours of treatment with LeTx, the growth of cancerous tumours in mice was halted. By 48 hours, the investigators detected dead cancer cells.
But could using a toxic chemical derived from anthrax really be safe? Is there any chance the toxin could spread from the tumour to the rest of the body? “The anthrax toxin LeTx kills only cancerous cells, without obvious side effects,” said Dr. Koo.
