Scientific developments
- Arteries may benefit from gene therapy
- Breast cancer mutation linked to further cancers
- Cervical cancer genes "switched off"
- Cord blood stem cells could create heart vessels
- Muscular dystrophy gene therapy hope
- Prostate cancer gene find - disease linked to infection
- Stem cell "stemness" pinpointed
Arteries may benefit from gene therapy
16 September - A new Finnish study in rabbits suggests an experimental gene therapy technique may help to prevent heart arteries from re-clogging after surgery has been performed to unblock them. If transferred to humans, the technique could assist in maintaining clear arteries, preventing further heart attacks and the need for further surgery. Currently, as many as one in five patients who have arteries unblocked suffer re-blockages within six months. In this latest research, damage to artery walls by free radicals and the failure of antioxidant production (as a result of surgery) was limited by directly delivering a gene that makes an extracellular antioxidant. This gene destroys free radicals, countering damage to the artery wall and prevents arteries from re-clogging. The gene is delivered in a modified virus. Significantly, the treatment is required only once, at the time of artery surgery. Follow-up in the rabbits indicated that production of free radicals in the rabbits was significantly reduced. Researchers are now trying to develop an equivalent treatment for humans.
[Source: Reuters Health - Jacqueline Stenson]
Breast cancer mutation linked to further cancers
17 September - Mutations in the gene BRCA1 are known to increase a person's chances of developing breast cancer, and ovarian cancer in women. However, results from two new studies suggest these mutations could also be involved in the development of other cancers including colon, uterine, pancreatic and prostate cancer, although the overall risk is small. In one study, UK researchers studied data from over 11,000 people with a family history of breast or ovarian cancer, who also had a family member carrying the BRCA1 mutation. They found that women carrying the BRCA1 mutation were doubly susceptible to uterine and pancreatic cancers, compared with those not carrying the gene. The risk of cervical cancer was nearly four times as high.
In a separate study, US researchers analysed nearly 500 BRCA1 mutation carriers, comparing them to people in the general population. These comparisons demonstrated that women who carried the mutation were twice as likely to develop colon cancer, three times as likely to develop pancreatic cancer and 120 times as likely to develop fallopian tube cancer. Commentators on this research indicated that although this is the first time risks for other cancers have been associated with BRCA1 mutations, overall the risks are still rather small, suggesting no urgent need for further preventative strategies for carriers.
[Source: Reuters Health]
Cervical cancer genes "switched off"
14 September - UK researchers have been able to effectively "switch off" a human papillomavirus gene known to trigger cervical cancer. The switching-off process was achieved using a new highly targeted technique, termed RNA interference, which selectively silences genes. The study, undertaken using cells in culture, demonstrates that this selective silencing is able to eliminate human cervical cancer cells, leaving healthy cells unharmed. In the research, two genes of the papillomavirus (present in 90% of cervical cancers) were targeted with RNA interference, namely E6 and E7. E6 and E7 are responsible for driving the abnormal cell proliferation characteristic of cancer. Researchers designed two short interfering RNA sequences for each gene, and introduced them into cells. The siRNAs targeted messenger RNA (the molecule responsible for carrying the DNA sequence from the nucleus to the cytoplasm, where protein assembly occurs), degrading it and preventing protein synthesis. Silencing the E7 gene was found to completely prevent cell proliferation, also causing significant cell death. The research therefore has significant therapeutic potential for the treatment and possible prevention of human cervical cancer.
[Source: BMJ - Susan Mayor]
Cord blood stem cells could create heart vessels
12 September - New research indicates stem cells extracted from umbilical cord blood could provide a useful tool for heart artery remodelling and reconstruction. This represents a significant advance towards tissue engineering - the creation of living replacement tissue that can be remodelled as required. Heart operations in particular are set to benefit, as this kind of surgery often requires the implantation of new vessels.
In the collaborative research between Swiss and German scientists, heart vessel frames were constructed using polymers capable of bioabsorption. The frames were then seeded with human cord blood cells and incubated. The result was viable tissue cells, with a strength similar to that of natural tissue. Key tissue proteins were also present. The researchers were positive about their findings, stating that tissue engineering with cord cells was feasible. They were pleased with the growth properties of the cells and the expected plentiful availability of these cells as a source.
[Source: BioExchange]
Muscular dystrophy gene therapy hope
16 September - New research suggests the debilitating effects of muscular dystrophy could be ameliorated, with new experiments in mice demonstrating a partial correction of the disease. Researchers inserted a gene into muscle of the mice to restore the protein, dystrophin, lacking in those who suffer the ultimately fatal muscle-wasting disease. To insert the dystrophin gene into the muscle of the mice, it was fused with a modified virus and injected into the leg muscle of mice suffering a disorder much like Duchenne muscular dystrophy. Within a month of treatment, a 40% improvement in the mice's muscle action was observed. An analysis of muscle around the injection site indicated that the tissue was producing the dystrophin protein at a level 25 to 30% of normal levels. However, the challenge remains to determine how to deliver the gene to muscles throughout the body. Safety concerns regarding the use of modified viruses also need to be addressed.
[Source: Associated Press - Paul Recer]
Prostate cancer gene find - disease linked to infection
15 September - US researchers have identified a gene significant to the development of prostate cancer. The gene, MSR1, usually helps immune cells to remove cellular debris resulting from infection. Activity in such immune cells has been observed to increase in the early stages of prostate cancer, suggesting that a mutation in the MSR1 gene could inhibit the ability of these immune cells to "clean up" prostate infections - causing damage that may lead to cancer. The study, published in Nature, involved men from a variety of ethnic backgrounds. One particular mutation in the MSR1 gene was shown to be present in 4.4% of men with prostate cancer, compared with just 0.8% of men who did not have the disease. Another gene was found in 12.5% of men with prostate cancer, and only 1.82% of men who did not. The MSR1 is one of many thought to be linked to prostate cancer. Researchers are hopeful that a screening programme for mutations in the gene could one day lead to better diagnosis or prevention of prostate cancer. As the gene is also thought to make the cancer spread more rapidly, those who have the mutation could be given a more aggressive treatment regime than those who do not.
[Source: BBC News]
Stem cell "stemness" pinpointed
13 September - Two new research projects have identified genes shared by several kinds of stem cells - a finding seen as key both to understanding how such cells operate and identifying new kinds of cells. In the first project, researchers at Harvard University, in conjunction with Howard Hughes Medical Institute, "profiled" the genes found in several kinds of mouse stem cells. 216 genes were identified that were expressed at high levels in three stem cell types. It is considered that within these 216 genes lies the key to several core stem cell properties ("stemness"), such as self-renewal. The second study suggests that stem cell similarities could also apply to humans. Researchers from Princeton University compared haematopoietic stem cells (which give rise to blood) in humans and mice, finding they expressed several of the same genes. The researchers believe this similarity could represent a "molecular signature," ruling the properties shared by various kinds of stem cells.
[Source: Reuters Health]
