Note in Science page
Created Oct 29 07, Updated Oct 29 07 17:46
Cancer-Killing engineered Vaccinia virus go to comments

Targeted virotherapeutic for the systemic treatment of cancer in humans

Researchers at Stanford University and Jennerex Biotherapeutics have engineered vaccinia virus (cousin of smallpox virus) into a cancer killing machine.
The virus was engineered from the strain of vaccinia virus that is the basis for the vaccine that has been used in hundreds of millions of people in vaccination against smallpox, so should therefore be safe for humans.


image from the-scientist.com

Viral genes were deleted in order to restrict virus replication to cancer cells (Western Reserve strain of vaccinia [WR] with deletions in the viral thymidine kinase [TK] and vaccinia growth factor [VGF]). The resulting virus infects cancer cells while leaving healthy cells alone. In addition, the researchers also spliced a gene (human GM-CSF) into the virus that makes it produce granulocyte-macrophage colony-stimulating factor (GM-CSF), which induces the body’s immune system to recognize and attack tumors infected by the virus, meaning that the virus also enhances the host immune response against cancer cells.
Granulocyte are now known to be an important factor in body’s responce to cancer, see: Rare People Have Extreme Anti-Cancer Immune Cells (15% of human may be especially resistant to cancer thanks to their granulocytes, see also my note about SR/CR mice).

One-Two Punch: After the virus has destroyed most of the tumors, it stimulates an elevated immune system response, that will mop up remaining cancer cells.

In a study appearing Thursday October 25 2007 in the Journal of Clinical Investigation, the researchers report that the new treatment resulted in the suppression of spleen tumors and (lung) metastasis in the rabbits on which it was tested. The virus is now headed toward phase II trials with human patients.

Scientists have been trying to genetically engineer viruses to selectively infect and destroy cancer cells for more than 10 years, but with limited success. Vaccinia represents a promising ‘platform’ for the design of oncolytic viruses (has a long history of human use during the smallpox eradication campaign, spread extremely rapidly within tissues, inherent tumor selectivity of certain strains, etc…). In addition, with the new JX-963 therapy, the virus doesn’t have to do the work alone – it elicits the body’s own defenses to mop up cancer cells.

Human trials (on patients with any form of solid tumor cancer) are expected to begin early next year.

Rational strain selection and engineering creates a broad-spectrum, systemically effective oncolytic poxvirus, JX-963

sciencenow link
newscientist link
wired link


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