'Nanocell' May Prove to the Triple Threat to Cancer Cells

[Guest guest]

Tuesday, October 31, 2006

Nanotech Triple Threat to Cancer

New technology finds, flags, and kills tumor cells.

By Nasr

This nanocell, designed by University of Texas researchers, fights

cancer in several ways. Using targeting molecules (orange

triangles), it finds and enters cancer cells; then it releases

chemotherapy drugs (red hexagons) and imaging particles (brown

circles) into the cells from its core. The drugs attack the tumor

while the imaging particles help doctors monitor tumor death.

(Credit: Jinming Gao, University of Texas Southwestern Medical

Center at Dallas)

Nanotechnology-based drug treatments are already starting to be

approved for use, but so far they are neither very precise nor very

potent. Current cancer-fighting nanomedicine, which involve little

more than nanoscopic containers packed with chemotherapy drugs,

reaches tumors by leaking through holes in tumor blood vessels and

gradually releasing a drug. To kill appreciable amounts of the tumor

this way, doctors must flood the body with these drug-bearing

nanocarriers, says Jinming Gao, associate professor of oncology and

pharmacology at the University of Texas Southwestern Medical Center

at Dallas. These can get soaked up by the body's natural filters,

such as the liver and spleen, in which they can cause side effects,

he says.

What's more, doctors can't get a good view of what's happening once

nanocarriers are administered. They don't know whether the

nanocarriers are reaching targets or delivering drugs until they

remove tissue from the patient, the tumor starts to shrink, or the

first side effects appear. It's like fighting cancer in a " black

box, " Gao says.

Now a growing cadre of researchers are developing next-generation

nanomedicine platforms that can both deliver drugs only to cancer

cells and allow doctors to monitor the progress of the treatment.

The University of Texas system delivers both an anti-cancer drug and

a highly effective magnetic resonance imaging (MRI) contrast agent

to allow doctors to see that the drug is being delivered to a tumor.

The nanocarriers are made of polymers with an inner core that traps

doxorubicin, a common chemotherapy drug, and iron-oxide particles

that show up clearly with MRI. Polymer strands on the outside of the

nanocarrier bear targeting molecules that are recognized only by

tumor blood-vessel cells. The nanocarriers latch on to the vessel

cells, and the cells engulf the carriers. The polymer releases the

drug once inside the cell, where it is most effective.

Read the rest at:

www.technologyreview.com/read_article.aspx?id=17679 & ch=biotech