Experiments indicate promising future for nanotechnology in cancer treatment

The research brings doctors one step closer to being able to inject patients with nanoparticles that bore inside tumours and release powerful doses of cancer-killing drugs while leaving the rest of the body unscathed.

After seeing how the mice were cured of human prostate cancer with the technology, cancer specialists gathered at the European Cancer Conference in Paris on Tuesday praised the work as impressive and said they had high hopes for its application to patients.

"There are a lot of candidates for intelligent carriers, and these nanoparticles are among them," said Dr. Gordon McVie, a professor at the European Institute of Oncology in Milan, Italy, who was not involved with the research.

"This is a new system, and the more systems we have, the better, because we'll probably be lucky if we get one system to work out of 10," McVie said. "It looks as if it could be quite good."

Dr. David Kerr, a professor of clinical pharmacology and cancer therapeutics at Oxford University in England who was not connected with the research, said the latest approach outlined at the conference may have the edge over others.

Previous designs of nanoparticles have used antibodies to zone in on cancer cells.

"The body's immunodefence system can create antibodies to the therapeutic antibodies, deactivate them and prevent the antibody binding to the right cancer cells. This looks like a step forward," Kerr said.

Nanotechnology is the science of manipulating matter smaller than 100 nanometres and taking advantage of properties that are present only at that level, such as conductivity. A nanometre is one-billionth of a metre, or about one-millionth the size of a pin head. The prefix comes from "nanos," the Greek word for dwarf.

Nanotech has been around for several decades, but only now is its potential starting to be realized. Medicine is expected to be one of the fields to benefit most from the technology. In cancer, it is hoped the technology will allow for more precisely targeted drugs and surgery and less toxic chemotherapy.

The study, conducted by scientists at Harvard Medical School and the Massachusetts Institute of Technology, which are pioneering cancer nanotechnology, involved engineering nanoparticles embedded with the cancer drug Taxotere. The particles were then injected directly into human tumours created from prostate cancer cell lines and implanted into the flanks of mice. The mice were watched for 100 days.

The technology being tested involves a nanoparticle made of a hydrogen and carbon polymer with bits of drug bound up in its fabric and attached to a chemical that hones in on cancer cells. The polymer gradually dissolves, exposing the nuggets of drug little by little.

The mice were divided into five groups, including one that had their tumours injected with ineffective saltwater. A second group died after injections of a nanoparticle containing no drugs.