Eradication of resistant prostate cancer by a novel gene therapy

Prostate Cancer :: Eradication of resistant prostate cancer by a novel gene therapy

A research team at Columbia University has designed a novel viral-based gene therapy they say blasts through a body, targeting both primary and distant tumors, while leaving normal cells untouched.

In the 15 mice they tested, injections of the therapy in tumors on one side of the mouse eliminated those cancers as well as tumors on the other side of the animal?s body, producing a cure in all of the mice.

This study tested this "dual cancer-specific targeting strategy" with aggressive therapy resistant prostate cancer. The researchers have also shown it works in animals with breast, and melanoma tumors.

An earlier version of the therapy showed powerful effects in a phase I clinical trial, said Paul B. Fisher, M.Ph., Ph.D., professor clinical pathology at Columbia. This improved treatment appears to be a much "smarter bomb with potential of treating metastatic and therapy-resistant cancers," he said.

"The beauty of this approach is that two methods are being used to destroy a tumor," said Devanand Sarkar, M.B.B.S, Ph.D., the study?s primary author, associate research scientist at Columbia. "The virus we designed replicates within a tumor, and at the same time produces a massive amount of a cancer killing compound. Either action alone is damaging and potentially deadly, but together they are lethal."

Columbia researchers built the therapy around their earlier, pivotal discovery of a cytokine (a signaling protein) called melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24). A technology developed in the Fisher laboratory, "subtraction hybridization," applied to human melanoma, induced the cancer to revert to a more normal state, allowing comparison of genes expressed in both states. They discovered mda-7/IL-24 was progressively down-regulated as melanoma developed. In its normal state, the cytokine may affect growth and immune regulation, whereas expression at high levels kills cancer cells.