The Cross-Border Biotech Blog

Biotechnology, Health and Business in Canada, the United States and Worldwide

Friday Science Review: September 23, 2011

Gene Therapy Tailored to the Prostate

University of British Columbia ♦ Published in Cancer Gene Therapy (npg), September 16, 2011

Prostate cancer cells tend to over express the protein translation initiation factor 4E (eIF4E). With this knowledge on hand, researchers at the University of British Columbia experimented with a variety of 5’UTRs to see which was most sensitive to eIF4E, and hence, which would drive the most efficient gene transfer for treating prostate cancer. The untranslated region (UTR) of mRNA is a non-coding portion of RNA upstream of the coding region which provides a docking site for translational machinery during protein synthesis. Researchers investigated the 5’UTR of fibroblast growth factor-2 (FGF-2) and another two from ornithine decarboxylase. It was determined that the 5’UTR of FGF-2 provides the best translational efficiency, as measured by a GFP reporter. Findings were confirmed by injecting viral vectors containing the three 5’UTRs into the prostates of PTEN deficient (tumour bearing) mice.

Mechanism of Post-Stroke Immune Suppression Elucidated

University of Calgary ♦ Published in Sciencexpress, September 15, 2011

One of the consequences of stroke is severe inflammation of the brain. As a result, the body has evolved an immune suppression mechanism to compensate for this swelling to avoid brain damage. The exact nature of this mechanism remains unknown. It seems that immunomodulation of natural killer T (NKT) cells may be one avenue that the body takes to avoid inflammation. Using a mouse model of stroke researchers recently showed that the nervous system suppresses activation of NKT cells by altering its innovation on the liver, the organ in which NKT cells primarily reside. Immune suppression following stroke is problematic as it can lead to infection, especially in the elderly, where the immune system is already somewhat diminished. A better understanding of immunomodulation following stroke should aid in the development of drugs that support the immune system post-stroke.

Excisable Marker for Creation of Pox Vectors

University of Ottawa ♦ University of Alberta ♦ Published in PLoS ONE, September 8, 2011

Gene transfer requires effective vectors in which to carry genetic material. Viruses are often exploited to produce DNA vectors, where their genomes are modified through the addition of foreign DNA of therapeutic value. The process of creating viruses for gene transfer begins with the introduction of foreign DNA to a packaging cell type using circular pieces of DNA known as plasmids. Once inside the cell, these plasmids are taken up by the genome of the packaging cell. The cells are then used as factories that produce viral particles containing therapeutic DNA. For the process to be efficient, one must be able to detect cells that have been successfully transformed with plasmid DNA. Reporters such as green fluorescent protein or luciferase or often used, but by incorporating them into plasmids non-therapeutic DNA is left behind that serves no purpose. Researchers have circumvented this issue by creating plasmids containing an excisable marker element. These plasmids were used to create marker free recombinant poxviruses. To allow for removal of the reporter, specific sequences of DNA known as lox sequences were placed on either side of it. The Cre/Lox system was then used to excise the marker prior to the production of viruses. Viruses for gene transfer without marker elements are considered more therapeutically relevant, as they do not contain extraneous traces of DNA.





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