ASGT Press Release 

Today's findings from the ASGT 6th Annual Meeting: New research on gene therapy for cancer

Treating cancer with apoptosis

(WASHINGTON, DC) - A group of researchers have attempted to activate the cell death pathways to treat several kinds of cancer, according to a study presented today at the 6th Annual Meeting of the American Society of Gene Therapy (ASGT).

The uncontrolled expansion of malignant tumors is caused by failure of one of the many systems that control whether a cell will divide or die. It is possible to stimulate the pathways present in tumors cells to direct them to die, a process called apoptosis.

Sunil Chada, MD, and a group of researchers from Baylor Sammons Cancer Center, Dallas, and the M.D. Anderson Cancer Center, Houston inserted the gene mda-7 protein into an adenovirus vector and injected into tumors from 18 patients. The mda-7 protein is a potent stimulator of apoptosis.

The tumors began to secrete mda-7, stimulating widespread cell death in the injected tumors. It also activated the immune system of the patients against the tumors.

Treating prostate cancer

(WASHINGTON, DC) - Researchers have harnessed the cell killing properties of adenoviruses to treat prostate cancer, according to a study presented today at the 6th Annual Meeting of the American Society of Gene Therapy (ASGT). Andeoviruses replicate themselves by using the host cell's DNA and protein-making machinery to make their own DNA and viral proteins. Once a host cell is filled with a virus, it bursts, releasing viruses to infect other cells, continuing the process.

Theodore DeWeese, MD from Johns Hopkins Oncology Center, and colleagues engineered an adenovirus so that is could only replicate in cells producing proteins expressed in prostate tumors. In all other normal cells, this virus is inactive. When injected into prostate tumors, the virus replicates, kills the cells and releases thousands of viruses that can spread to other tumor cells.

In a clinical trial of 20 patients, the treatment halted the progression of the prostate tumors in X of Y treated subjects and was well-tolerated with no serious adverse events.

Activating immune system against prostate cancer

(WASHINGTON, DC) - In an ongoing clinical trial of prostate cancer treatment, researchers have developed a novel means of activating the immune system against prostate tumors. The research was presented today at the 6th Annual Meeting of the American Society of Gene Therapy (ASGT).

Previous research has shown that prostate tumor cells injected into a patient could induce an immune response against the tumor. To give the immune system a further boost, the research team, led by Natalie Sacks, MD, Cell Genesys, Inc., engineered a prostate tumor cell line to produce a protein called GM-CSF that can further augment the immune response against the tumor, and used these cells as a vaccine.

Thirty-three patients suffering from prostate cancer were treated on a monthly vaccination schedule for three months. In the first 15 patients treated, the spread of the prostate tumors was slowed, with levels reduced to undetectable during the post-treatment period.

Herpes virus shown to stimulate immune system against tumors

(WASHINGTON, DC) - A group of British researchers has combined the use of a virus that can kill tumor cells with a gene that can stimulate the immune system to react against the tumor cells to treat a variety of human tumors, according to a study presented today at the 6th Annual Meeting of the American Society of Gene Therapy (ASGT).

Researchers, led by Jennifer Hu, MD from the Imperial College of Science and Medicine, London, have engineered a herpes virus to produce a protein called GM-CSF. When infected into tumor cells in culture, GM-CSF was produced and cell killing was efficient. Like the adenovirus, the herpes virus replicates very quickly in tumor cells, but slowly or not at all in normal cells. The herpes virus preferentially kills tumor cells.

The engineered herpes virus was injected into different types of tumors in 11 patients. The protein GM-CSF was produced and the immune system was activated in and around the tumors in all of the patients. In addition, samples taken from each of the tumors showed evidence of tumor death.

The American Society of Gene Therapy is the largest medical professional organization representing researchers and scientists dedicated to discovering new gene therapies. ASGT was established in 1996, and has grown to more than 3,000 members. It is committed to promoting and fostering the general field of research involving gene therapy and to promoting professional and public education in all areas of gene therapy.

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