Despite their lethality, and perhaps because of it
The anthrax disease evokes an immediate association with biological warfare and weapons of mass destruction. The anthrax bacteria are considered the most dangerous and their ability to cause rapid death has been known to scientists for a long time. But despite their deadly properties, and perhaps because of these properties, these bacteria may open the door to a promising new treatment against many types of cancerous tumors.
Last week, the BBC reported that scientists from the US National Institutes of Health were able to destroy cancerous tumors with the help of a toxin produced by anthrax bacteria. In laboratory experiments conducted on mice, the substance was found to be extremely effective: after one treatment with it, some of the cancerous tumors shrank by 92%.
When anthrax bacteria attack the body they stick to healthy cells and start producing toxins that kill them. The researchers used genetic engineering techniques to make the anthrax bacteria produce the toxin only when they attach to cancer cells in the body, and not produce it in contact with normal healthy cells. How will the bacteria know to stick only to the cancer cells?
Cancer cells have a high concentration of the protein urokinase; In healthy cells, however, there is a lower concentration of the protein. The anthrax bacteria were genetically modified so that they would produce the deadly toxin only when they are in contact with a cell containing a high concentration of urokinase, i.e. in the tumor cells, thus preventing damage to the healthy cells.
The researchers reported that approximately 12 hours after exposure to the toxin, cancer cells began to die very quickly. The tests were conducted on a variety of tumors in mice that simulate human tumors. After two cycles of treatment, an 88% shrinkage was recorded in the tumor type - fibrosarcoma, a tumor that affects humans mainly in the bones of the pelvis and limbs.
In another experiment, the effect of the toxin on melanoma skin cancer was tested. Skin cancer of this type is considered particularly serious; Although it accounts for only 4% of skin cancer cases, it is responsible for about 79% of deaths among those with skin cancer. After initial treatment with the anthrax toxin, an initial shrinkage of 17% was recorded in the tumor. After the treatment, most of the tumors were destroyed and the remaining tumors shrank almost completely. Despite the rapid damage and the success in destroying most of the tumors, no damage was observed to the healthy skin cells and the hair roots adjacent to the tumor. The researchers hope that these results confirm that the anthrax toxin acts selectively on cancer cells and does not damage the surrounding tissues.
The head of the research group, Dr. Steve Lepele, said in an interview with the BBC: "The fact that the toxin we produced can effectively eliminate several types of solid tumors raises the possibility that its effectiveness will be even higher in the treatment of blood cancer, when access to the cancer cells is better. We are looking into this possibility now."
In response to the publication, cancer researchers from various research institutes argued that it is necessary to wait until further tests are performed before it is possible to confirm the research findings. The researchers emphasized that the use of the toxin produced from the anthrax bacteria on human subjects will not be possible before the completion of many additional tests.
