17 May 2004
Genetically Engineered Viruses Set To Fight Cancers
by Kate Melville
Cancer Research is carrying a report on a genetically engineered virus that can selectively kill cancerous cells in the lung and colon while leaving healthy cells intact.
The research - carried out by William Wold and colleagues at Saint Louis University School of Medicine - could lead to a new class of cancer therapies that selectively kill cancer cells.
"These engineered viruses kill cancer cells through a mechanism that is completely different from chemotherapy or radiation," said Dr. William Wold. "These viruses have the potential to treat many cancers that are resistant to currently available therapeutics. It also may be possible to use these viruses in combination with other therapies to create novel treatment regimens."
Dr. Wold and his colleagues Karoly Toth, Konstantin Doronin, Ann E. Tollefson, Mohan Kuppuswamy, Baoling Ying, Jacqueline Spencer and Maria Thomas have been working for some years on methods to convert the relatively benign "adenovirus" that causes symptoms similar to the common cold in children into an anti-cancer treatment that attacks and destroys cancerous cells.
Wold's group has developed several new "adenovirus cancer gene therapy vectors," changing these genes so the virus will attack cancer cells.
"Some of our vectors are designed to destroy many different types of cancers, others are designed to be specific to colon or lung cancer. In preclinical testing these vectors were highly effective against cancerous tumors and did not harm normal tissues."
The "oncolytic adenoviruses" have been engineered to kill cancer cells via viral replication and can be engineered so that they are active in specific types of cancer cells. The published research indicates that both efficiently killed cancer cells in culture. Specifically:
- INGN 009, which has been designed to kill cells that carry a mutation common in many colon cancers, efficiently killed cultured colon cancer cells, but not lung cancer cells.
- INGN 007 effectively killed both types of cancer cells. In an animal model of colon cancer, injection of either INGN 007 or INGN 009 into tumors suppressed tumor growth more efficiently than a negative control (five-fold and ten-fold suppression, respectively).
- INGN 007 also completely suppressed tumor growth in a lung cancer model of disease.
Louis Zumstein of Introgen Therapeutics Inc., which has licensed rights to these oncolytic viruses and other related technologies, said: "These preclinical data are very promising, and support our belief that oncolytic adenoviruses have enormous potential as a new class of cancer therapies that may provide potent and selective killing of cancer cells. These data also illustrate the flexibility of engineered oncolytic adenoviruses to target selected tumor types with great specificity."