Scientist devises method to kill cancer with a dose of arsenic

Animal tests have shown arsenic effectively kills breast, ovarian and lung cancer cells

Cancer could be killed with a dose of arsenic poison, a renowned physician has claimed.

Arsenic, which is known to have killed many a human being back in the olden days when it was used as a poison, is usually associated with an increased risk of cancer if we are exposed to it.

However, one scientist, namely Tom O'Halloran, an expert on inorganic compounds, believes it could be used more broadly to kill cancer.

While low doses of arsenic trioxide have already shown a 95 per cent remission rate in acute promyelocytic leukemia (a type of blood cancer) O'Halloran says arsenic can also shut down the growth of other cancers as well, such as solid tumors in the breast, lung and ovaries.

What limits arsenic's broader application in cancer is its toxicity

"What limits arsenic's broader application in cancer is its toxicity," O'Halloran explained. "So, we asked whether we could control that toxicity but still allow its destructive effect to manifest only in cancer cells."

To do this, O'Halloran and his team put insoluble particles of arsenic into a liposome, a tiny droplet of fat about one-hundredth the width of a human hair, creating what they called a "nanobin". These nanobins, when injected into the bloodstream, release arsenic only once they reach cancer cells and thus healthy cells remain unscathed.

"The cancer tumors start collecting the nanobins in ways that normal tissue doesn't, building up the concentration of these arsenic-loaded liposomes in the tumor," O'Halloran explained.

And because of the way cancer cells process nutrients and make energy, they are slightly more acidic than normal cells. That acid helps dissolve the arsenic particles inside the nanobins, releasing the active drug inside the tumor.

"The acidic character of the tumor helps it grow and proliferate, which is something we can take advantage of with nanobins," O'Halloran says.

The doctor has found a way to exploit the unique features of tumors to smuggle arsenic directly into cancer cells: the 'leakiness' of the newly created blood vessels helps nanobins collect in the tumor, and the acidic interior of the tumor coaxes the arsenic out.

Working in collaboration with the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Illinois O'Halloran's team has shown in animal models that nanobin injections effectively kill breast, ovarian and lung cancer cells.

O'Halloran and his collaborator Teresa Woodruff, who is chief of reproductive biology research at the Feinberg School of Medicine, showed that unlike other drug regimens, nanobin treatment is "ferto-protective," preserving fertility while killing cancer.

"I think this is really critical for drug delivery and development," O'Halloran added.

"In addition to fertility concerns, heart toxicities are common with cancer drugs, and we often don't deal with them until the late stages of drug discovery. Delivery mechanisms like nanobins could help protect healthy tissue from these and other harmful effects of cancer treatment."