To mark the 10th anniversary of the sequencing of the human genome the BBC aired a documentary yesterday evening entitled “Miracle cure: a decade of the human genome” that can be viewed on the BBC iPlayer. It was an enjoyable look at what has been accomplished since the famous announcement at the White House in June 2000, and while I think the program could have done with exploring some of the science in more depth, it gave a good overview and didn’t shrink from the sheer complexity of many of the questions that face scientists who are now attempting to understand the genome.
The program followed three individuals as they sought to understand what impact the knowledge gained from studying the genome could have on illnesses that have affected them, breast cancer, cystic fibrosis, and alcoholism, and what basic, applied, and clinical research is currently underway. The case of a woman whose breast cancer is linked to a defective BRCA1 gene turned to discussion of the potential for the development of personalized medicine – treatments that are tailored to the genetic makeup of an individual patient’s cancer cells. Animal research plays a very important role in the development of targeted therapies that can be used in personalized medicine, and an early example of this is the drug Herceptin, which is used to treat cancers that express the HER2 gene.
The cystic fibrosis thread focussed on the development of gene therapy and clinical trials now underway under the direction of Professor Eric Alton of the UK Cystic Fibrosis Gene Therapy Consortium. These gene therapy trials use lipid spheres to transport working copies of the CFTR gene – defective in cystic fibrosis – to the lungs of patients, and the particular lipid formulation used in these trials, known as GL67A was selected after careful evaluation against other candidates, first in CF mice and then in sheep (1). Mice models of cystic fibrosis have helped researchers to understand more about the disease and to assess therapies, but until very recently research has been hampered by the lack of a large animal model of cystic fibrosis that models the lung pathology of cystic fibrosis. This situation finally changed in 2008 when scientists at the Universities of Iowa and Missouri produced genetically modified pigs that lack the CFTR gene and develop all the pathologies that are characteristic of cystic fibrosis in humans. This new animal model for cystic fibrosis will be very useful for evaluating the safety and efficiency of new gene therapy techniques as the science advances.
Finally the thread on the influence on genetics on alcoholism was a reminder of just how complex the interaction between an array of genetic variations and the environment can be, and that while it may be possible to identify factors that predispose an individual towards a particular condition it is often difficult, if not impossible, to identify a single cause that tips the balance. Considering the enormous damage caused to society by addiction, and the high failure rate of addiction treatment programs, there is no doubt that addiction research is a neglected area within biomedical science. This is sad because research into the physiological underpinnings of addiction can aid the development of more effective treatment programs. Hopefully the identification of genes that predispose certain individuals to addiction will help society to realise that science can make an important contribution to solving this medical and social problem.
1) Griesenbach U, Alton EW; UK Cystic Fibrosis Gene Therapy Consortium. “Gene transfer to the lung: lessons learned from more than 2 decades of CF gene therapy.” Adv Drug Deliv. Rev. Volume 61(2), Pages 128-39 (2009) DOI: 10.1016/j.addr.2008.09.010.