Electrical Weapons Fight Cancer

Irreversible electroporation improved with boron nitride nanotubes

(RxWiki News) Experimental laboratory research uses space-age materials developed by NASA to improve the latest field in cancer treatment, creating electrical fields to kill tumor cells.

Irreversible electroporation, also known as nano-knife surgery, is the newest surgical method for advanced cancers where surgery cannot be performed, including kidney, liver and pancreatic cancers.

While the field is only a few years old, scientists have already doubled the effectiveness of the technique. The irreversible electroporation technology uses electricity to create tiny holes in cells, causing them to self destruct.

"Ask your oncologist about irreversible electroporation."

Using boron nitride nanotubes developed by NASA, the amount of cancer cells killed doubled from 40 to 88 percent in laboratory experiments, results of a joint project between elements of NASA, the Department of Energy, and a group of Italian scientists from Scuola Superiore Sant'Anna in Pisa.

So far clinical trials using nano knife surgery have been successful in several types of tumors, being preferred for use in difficult areas where the cancer has advanced or the tumor is too intertwined with important nerves, or blood vessels.

While the electric field is equally harmful to both normal and cancerous cells, the rules of cellular repair mean that in the end, healthy cells will heal better.

Testing the boron nitride nanotubes alone, without using electricity, showed that 25 percent of cancer cells were dead within 24 hours as a result of exposure, showing that the molecules act as an effective chemotherapy by themselves.

Combining boron nitride nanotubes with irreversible electroporation enhances the effects of both treatments, as cells that would survive either electricity or the boron nanotubes alone are unable to withstand a dual assault.

The use of irreversible electroporation as a way to kill cancer cells is only a few years old. The technology uses a carefully created electrical field to induce cellular suicide in the cancer by creating brief holes in the surface of the cell with electricity, the same holes that the boron nitride nanotubes then use to enter the cell.

Metal probes are inserted around the tumor, allowing exact targeting of a cancers that may be hard to reach using conventional methods, or when radiation isn't an option.

Unlike other similar methods, and despite the nickname of nano-knife, the damage caused by irreversible electroporation occurs on a cellular level, and doesn't use heat, radiation or freezing to kill cells, making the damage more easily repaired.

"Irreversible electroporation is a way of putting holes in the wall of a tumor cell," said Michael W. Smith, PhD and chief researcher. "The cell will literally go, Oh, something's terribly wrong, and kill itself. That's called apoptosis," he added.

By using a carefully calculated series of electrical zaps, cells in the region die. Testing so far supports the researcher's theory that that healthy cells will replace themselves, with the tumor being significantly more affected by the treatment.

Importantly, this method of forcing natural cellular death is less harmful to surrounding tissue and the healing response can begin immediately, in comparison to treatment with radiation or chemotherapy, where destructive treatment effects can linger.

"They were able to get, in a petri dish, more than double the effectiveness. So, this technique works twice as well with our nanotubes on the cells than without them. That's a big deal, because you can either use a lot less voltage or kill a lot more cells," said Smith.

“Once we determine the treatment area, we insert the electrode probes through the skin into the tumor, creating a field around the lesion. We then send short, intense electrical pulses - each less than 100 microseconds - between the probes, killing the tumor cells. Then the body’s normal healing response takes over, naturally producing new cells and absorbing the cells that have been targeted,” said one of the original pioneers of the technique, from the University of Maryland, Fred Moeslein, MD, PhD.

While the technique of irreversible electroporation is still being refined, researchers hope to move their testing of the boron nitride nanotubes from the laboratory to clinical trials within the next year.

The research data was published in the journal Technology in Cancer Research & Treatment on March 28, 2012.

Researchers did not disclose any conflicts of interest to the public.

Review Date: 
May 3, 2012