Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mouse study reveals human X-SCID gene therapy poses substantial cancer risk

27.04.2006
New animal studies conducted at the Salk Institute for Biological Studies show that the only human gene therapy treatment to date considered to be largely successful, is, in fact, riskier than realized.

The Salk researchers, led by Inder Verma, Ph.D., a professor in the Laboratory of Genetics, discovered that the healthy copy, which replaces the defective gene can itself promote cancer development. Their findings appear in this week’s issue of the journal Nature.

Niels-Bjarne R. Woods, Ph.D., a post-doctoral researcher in Inder Verma’s team followed mice treated with the IL2RG gene three times longer than any study had ever before, and found that one-third of the animals developed lymphoma later in their life. This is the same gene being given to patients with X-linked severe combined immune deficiency (X-SCID) – commonly known as the "bubble boy" syndrome – in small clinical trials being conducted in France, the United States, the United Kingdom, and Australia.

Although replacement of IL2RG can cure X-SCID, the Salk scientists urge caution in the use of such therapy on the basis of their new findings.

"We were surprised by the strength of the association between IL2RG gene therapy and development of lymphoma," says Woods. "These results suggest that curing X-SCID by replacing IL2RG in the manner it is currently being done puts patients at an increased risk of developing cancer."

Woods adds that the study could explain why one of three children in the French trial developed T-cell leukemia. Two developed the disease because IL2RG inserted itself into the cellular genome next to a known cancer-causing gene and activated it, but the cause of the third cancer case had not been solved.

The French trial is the largest to date to test IL2RG gene therapy, and of the 10 children treated, nine were successfully cured of X-SCID, although cancer was diagnosed in three of the children. Halted for a time, the trial is now continuing on a case-by-case basis, according to Woods.

In the studies leading up to the human clinical studies, mice were studied post-transplant for less than 6 months, which is a traditional research protocol. The Salk research team, however, allowed the mice to live through their natural life span, which is about one-and-a-half years. Mice that developed lymphoma did so at an average of 10 months of age.

In the human gene therapy trials, leukemia did not appear until 2-3 years after treatment, Woods says.

"This indicates that preclinical experimental treatments involving transgenes should include long-term follow-up before entering a clinical trial," says Woods.

But, more fundamentally, the Salk study suggests that replacement of a gene that serves multiple functions in the body may be much more problematic than therapy to replace a gene that serves a single function, says Verma.

"The bottom line here is that if you replace a gene that has multiple effects, you have to know more about its regulation and its ability to affect other genes, and that requires extensive preclinical work and a much more careful analysis," he says.

X-SCID is caused by mutations in IL2RG, which provides instructions for making the common gamma chain protein. This powerful protein, found on the surface of immature blood cells in the bone marrow, works with other proteins to direct the growth and maturation of a number of different immune system cells, including T cells, B cells, and natural killer cells. These immune system cells that kill invading viruses and bacteria, produce antibodies as well as help regulate the entire immune system. Without the common gamma chain, these cells cannot develop normally, and are unable to protect the body.

Researchers who also contributed to this paper include Virginie Bottero, Ph.D., in the Laboratory of Genetics at the Salk Institute, as well as Manfred Schmidt, Ph.D., and Christof von Kalle, Ph.D., both at the Cancer Research Center in Heidelberg, Germany.

Gina Kirchweger | EurekAlert!
Further information:
http://www.salk.edu

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Scientists re-create brain neurons to study obesity and personalize treatment

20.04.2018 | Health and Medicine

Spider silk key to new bone-fixing composite

20.04.2018 | Materials Sciences

Clear as mud: Desiccation cracks help reveal the shape of water on Mars

20.04.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>