Česká Genetická Banka

SCIENCE: 20. 5. 2013

SCIENCE: (Poly)Combing the Pediatric Cancer Genome for Answers

"The rapid expansion of high-through-put DNA sequencing now enables the genetic analysis of human diseases at an unprecedented rate and resolution. In particular, whole-genome sequencing of rare childhood diseases promises fundamental insight into basic developmental processes and biochemical pathways (1). Indeed, this approach has identified the first mutations in histones—proteins that package DNA—in human disease (2, 3). About 80% of cases of diffuse intrinsic pontine glioma (DIPG), an aggressive, incurable childhood tumor of the brain stem, harbor these histone mutations. On page 857 of this issue, Lewis et al. (4) extend this story by showing that altered activity of polycomb repressive complex 2 (PRC2), a key developmental regulator of gene expression, is involved in the pathogenesis of gliomas carrying these mutant histones."

http://www.sciencemag.org/content/340/6134/823.summary

 

SCIENCE: Human Stem Cells From Cloning, Finally

"This time it looks like it's for real: Researchers have made personalized human embryonic stem cells with a method similar to how Dolly the sheep was cloned—though with an added jolt of caffeine. The success, which produced stem cells carrying DNA belonging to a baby with an inherited disorder, comes after years of work in monkey cells. A group is now reporting a recipe that works for human cells using somatic cell nuclear transfer."

http://www.sciencemag.org/content/340/6134/795.summary

 

NATURE: The shaping and functional consequences of the microRNA landscape in breast cancer

"MicroRNAs (miRNAs) show differential expression across breast cancer subtypes, and have both oncogenic and tumour-suppressive roles^{1, 2, 3, 4, 5, 6}. Here we report the miRNA expression profiles of 1,302 breast tumours with matching detailed clinical annotation, long-term follow-up and genomic and messenger RNA expression data⁷. This provides a comprehensive overview of the quantity, distribution and variation of the miRNA population and provides information on the extent to which genomic, transcriptional and post-transcriptional events contribute to miRNA expression architecture, suggesting an important role for post-transcriptional regulation. The key clinical parameters and cellular pathways related to the miRNA landscape are characterized, revealing context-dependent interactions, for example with regards to cell adhesion and Wnt signalling. Notably, only prognostic miRNA signatures derived from breast tumours devoid of somatic copy-number aberrations (CNA-devoid) are consistently prognostic across several other subtypes and can be validated in external cohorts. We then use a data-driven approach⁸ to seek the effects of miRNAs associated with differential co-expression of mRNAs, and find that miRNAs act as modulators of mRNA–mRNA interactions rather than as on–off molecular switches. We demonstrate such an important modulatory role for miRNAs in the biology of CNA-devoid breast cancers, a common subtype in which the immune response is prominent. These findings represent a new framework for studying the biology of miRNAs in human breast cancer."

http://www.nature.com/nature/journal/v497/n7449/full/nature12108.html

 

NATURE: Human stem cells created by cloning

"It was hailed some 15 years ago as the great hope for a biomedical revolution: the use of cloning techniques to create perfectly matched tissues that would someday cure ailments ranging from diabetes to Parkinson’s disease. Since then, the approach has been enveloped in ethical debate, tainted by fraud and, in recent years, overshadowed by a competing technology. Most groups gave up long ago on the finicky core method — production of patient-specific embryonic stem cells (ESCs) from cloning. A quieter debate followed: do we still need ‘therapeutic’ cloning?

A paper published this week¹ by Shoukhrat Mitalipov, a reproductive biology specialist at the Oregon Health and Science University in Beaverton, and his colleagues is sure to rekindle that debate. Mitalipov and his team have finally created patient-specific ESCs through cloning, and they are keen to prove that the technology is worth pursuing."

http://www.nature.com/news/human-stem-cells-created-by-cloning-1.12983

 

NATURE: Cell transplants stem seizures

"Stem-cell therapy can reduce seizures in epileptic mice.

Some forms of epilepsy are thought to be caused by dysfunctional cells in the hippocampus region of the brain. The affected cells, called inhibitory interneurons, help to regulate neural circuits. Robert Hunt, Scott Baraban and their colleagues at the University of California, San… (...)"

http://www.nature.com/nature/journal/v497/n7449/full/497290b.html