Nanoparticle cancer-fighter entering clinical trials

http://www.betterhumans.com/News/4511/Default.aspx

Designed to restore lost tumor-busting gene, treatment will be tested on 20 human subjects

The first clinical trial of a nanoparticle that restores a tumor-busting gene is expected to start this September.

The phase I study at Georgetown University Medical Center will enroll 20 people with advanced solid cancers, including most common tumor types.

The treatment, developed over a decade by researchers led by Esther H. Chang, is described in a Georgetown news release as follows:

[Chang and colleagues'] research has led to development of a tiny structure—measuring a millionth of an inch across—that resembles a virus particle that can penetrate deeply into the tumor and move efficiently into cells. The device is a "liposome"—a microscopic globule made of lipids—that is spiked on the outside with antibody molecules that will seek out, bind to, and then enter cancer cells including metastases wherever they hide in the body. These molecules bind to the receptor for transferrin that is present in high numbers on cancer cells.

Once inside, the nanoparticle, which the researchers call a "immunolipoplex," will deliver its payload—the p53 gene whose protein helps to signal cells to self-destruct when they have the kind of genetic damage characterized by cancer and by cancer therapies.

More than half of all cancer patients have cancer cells that have lost normal functioning of the p53 gene, so-called "guardian of the genome," and the Georgetown researchers believe that restoring the gene will improve the tumor-killing ability of traditional treatments.

The researchers think that that immunolipoplex is an advance over viral vectors used to deliver gene therapy because it doesn’t produce the kinds of immune responses seen with disabled viruses.

The nanoparticle has been proven to work in animals with tumors.

It has also been found to work synergistically with traditional therapies because the restored p53 protein pushes cancer cells that are damaged to self-destruct.

"We believe this approach will make it difficult for the cancer cells to become resistant to therapy," says Chang. "As a result, cancers treated with these liposomal formulations should be less likely to recur after therapy is complete."