The Cross-Border Biotech Blog

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

Monthly Archives: September 2011

Friday Science Review: September 30, 2011

The Dynamic Immunopeptidome

University of Montreal ♦ Published in Molecular Systems Biology, September 27, 2011

The human body has developed a complex system in which to identify self and non-self. The large majority of nucleated cells in the body display small peptides on the cell surface known as MHC I-associated peptides (MIPs). Although past theories have been conducive to the view that the creation and expression of these peptides remains the same regardless of cellular conditions, researchers now believe that the pattern of MIPs presented on a cell may in fact be dynamic and change according to metabolic conditions. Taking a high-throughput mass spectrometry approach, researchers investigated changes that occurred in the immunopeptidome of a mouse lymphoma cell line. In order to alter metabolism, cells in the treatment group were exposed to rapamycin, a potent inhibitor of the kinase mTOR which is known to regulate cellular homeostasis. Rapamycin induced wide-sweeping changes in the MIP composition on the cell surface. A major finding in this study is that the immunopeptidome displayed on the cell surface actually provides a representation of the various biological events occurring within the cell.

Calcium Channel Key to T Cell Development

University of British Columbia ♦ University of Calgary ♦ Oxford University ♦ Published in Immunity, September 23, 2011

Calcium channels are critical players in physiology, development, and cell metabolism. Researchers have identified a specific calcium channel, CaV1.4, that is essential for channeling calcium ions into the cytoplasm of naive T cells. Intracellular calcium stores control signaling, differentiation, and activation. Researchers also found that CaV1.4 is in part responsible for modulating T cell receptor induced rises in calcium stores. In order to investigate the effects that CaV1.4 has on cell homeostasis researchers used a method known as patch clamp. This technique can record the conductance of single cells. Measurements of thymocytes and peripheral T cells from mice deficient in the CaV1.4 channel indicate that the channel both increases intracellular calcium stores on its own and affects the ability of T cell receptors to elevate intracellular calcium stores. Findings also indicate that CaV1.4 may to a certain degree control survival of developing T cells.

Also see this review published in Trends in Biotechnology, on recent methods used to understand host-virus interactions and identify novel targets for diagnostic and therapeutic applications.

Expansion and Diversification Strategies in the Pharmaceutical Industry: Part 12 of Valuation and Other Biotech Mysteries

[Ed. This is the twelfth part in Wayne’s series. You can access the whole thing by clicking here. Please leave comments or questions on the blog and Wayne will address them in future posts in this series.]

Brand, human prescription drugs is the core business of the pharmaceutical industry. Risk can be diversified and potential reward can be increased by having drugs in multiple therapeutic areas. Expansion and diversification could also involve other types of drug products and healthcare activities. The best current example of healthcare diversification is Johnson & Johnson. If you look at the longer term stock chart (NYSE:JNJ), you will see that the share price continued to climb from 1999 to 2005 and has since been in a volatile trading range.

This post will look at expansion and diversification into generics, vaccines, consumer products, diagnostics, medical devices, animal health and pharmacy benefits management. Read more of this post

Mixed Reaction to U.S. Patent Reform

Guest post by Andrew Franklin, a colleague in the Pharmaceuticals and Life Sciences practice at Norton Rose.

With the passage of the America Invents Act of 2011, the United States’ patent system will change from a “first-to-invent” system to a “first-to-file” system for granting patents. Under the new system, patents will be granted to the first person to submit an application to the U.S. Patent and Trademark Office (“USPTO”) as opposed to the first person who first  invented the subject matter of the invention. This is the most significant change to US patent law since 1952.

While this legal reform aligns the US patent law with the rest of the world, it has been met with mixed reaction. Read more of this post

Monday Biotech Deal Review: September 26, 2011

Welcome to your Monday Biotech Deal Review for September 26, 2011.  Noteworthy news from last week included a hint that Labopharm will enhance its offer for the shares of Afexa Life Sciences if its two shareholder rights plans are waived or cease-traded by the ASC.  As well, Medicago announced a significant private placement for proceeds of up to $24.5M, and Valeant has announced its intention to refinance its secured credit facilities with a new $1.7bn facility.  Read more of this post

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.





Monday Biotech Deal Review: September 19, 2011

Welcome to your Monday Biotech Deal Review for September 19, 2011.  Of note in the past week was the extension of the hostile bid by Paladin Labs of Afexa Life Sciences to September 28th, the application by Merus to graduate to the TSXV, and the filing by Allon Therapeutics of a short-form preliminary prospectus.  Read on to learn more.  Read more of this post

Friday Science Review: September 16, 2011

Novel Genetically Encoded Calcium Indicators

University of Alberta ♦ Hokkaido University ♦ Kyushu University

Published in Science, September 8, 2011

Calcium transport is critical to normal physiology having an essential role in processes like neural communication and muscle contraction. As a result, the element has been at the centre of a large body of physiological research. Over the years researchers have attempted to trace calcium to monitor physiological reactions, such as neurotransmitter release from neurons or the contraction of cardiac cells. Fluorescent indicator proteins are one means in which to do this. When calcium is present in a system that contains a fluorescent indicator it becomes bound to the indicator causing it to emit a characteristic energy that can be observed using fluorescence microscopy. Although this technology has been around for decades, continuing advances in microscopy have placed new fluorescent indicators in demand. Researchers at the University of Alberta have constructed not just one, but a cassette, of calcium reporters for research use. This cassette is composed of indicators that fluoresce in one of three colours — blue, green, or red; a step up from previous indicators that could only weakly fluoresce in a green hue. These novel proteins are expected to advance our understanding of calcium’s contribution to physiology and allow researchers to complete experiments that were previously impractical to approach.

At the Interface

Holland Bloorview Kids Rehabilitation Hospital ♦ University of Toronto ♦ University of Pittsburgh ♦ Hospital for Sick Children

Published in PLoS ONE, September 7, 2011

Brain computer interface (BCI) technology may one day revolutionize the way humans control devices. Researchers are currently investigating BCIs as a means to translate mental thought to signals that can control external devices. If commercialized, the technology could be useful in areas such as virtual reality, wheelchair control, and speech in individuals that lack muscle control. Several different modalities have been developed to register thought, including electroencephalography, functional magnetic resonance imaging, and magnetoencephalography. However, these methods still have shortcomings that limit their practicality. A technique known as transcranial Doppler ultrasound (TCD), which measures cerebral blood flow velocity in the brain, has shown promise as a new paradigm for BCI systems. Using TCD, researchers were able to measure changes in the velocity of cerebral blood flow in response to a word generation task and a mental rotation task. The system was able to decipher between the two with high accuracy suggesting that TCD could one day be useful for the more complex tasks that BCI will demand.

Also checkout this review on the use of encapsulation technology for applying biofertilizers and biocontrol agents, and this review on extracting polyphenols from plants for analysis in the lab; both papers published in Critical Reviews in Biotechnology.

Monday Biotech Deal Review: September 12, 2011

Welcome to your Monday Biotech Deal Review for September 12, 2011.  We hope everyone had a restful labo(u)r day long weekend, both north and south of the border.  This week’s biotech deal review is a double feature owing to last week’s holiday.  There has been a lot of activity in the past two weeks, including the announcement of a friendly takeover bid of Afexa by Valeant (Afexa is already the target of a hostile bid by Paladin).  Read on to learn more.  Read more of this post

Friday Science Review: September 9, 2011

Astrocytes Modulate Basal Synaptic Transmission

University of Montreal ♦ Montreal General Hospital ♦ Published in Cell, September 2, 2011

The astrocyte, a larger flattened cell type relative to the neuron, regulates the growth and survival of brain cells through the release of various growth factors and proteins. Recent findings indicate that they are also involved in regulating basal synaptic transmission. Although it has been known for some time that astrocytes are involved in modulating sustained synaptic transmission in the brain, researchers are in less agreement over whether or not astrocytes modulate basal synaptic transmission involving single synapses.  In this study, researchers found that astrocytes were activated by single action potentials and responded to this activation by releasing purines, specifically adenosine, which in turn increased basal transmission. It is believed that astrocyte activation occurs by way of the metabotropic glutamate subtype 5 receptors found on certain functional areas of the astrocyte process. After being release, purines bind to presynaptic A2a receptors on neurons, heightening basal synaptic transmission.

Neurogenesis Regulated by Alternative Splicing

University of Toronto ♦ Hospital for Sick Children ♦ King’s College London ♦ Published in Molecular Cell, September 2, 2011

Researchers have discovered a key mechanism that regulates the complex process of neurogenesis. Like many complex processes in the body, the process of neural development is controlled by a large array of genes and regulatory pathways. It appears that neurogenesis is activated by a protein known as nSR100, which alternatively splices another gene REST. Alternative splicing occurs when a gene is not transcribed by the cell’s protein machinery in its regular form. Instead, an alternative form, slightly different than the regular form (known as an isoform), is produced. This isoform can have reduced function or lose function entirely. In the case of REST, its alternative splice isoform REST4 still functions, however has vastly reduced activity. REST typically negatively regulates a panel of genes that promote neurogenesis, so in the presence of the isoform neurogenenesis increases. Experiments with mice confirm these findings; blocking nSR100 in the mouse brain impairs neurogenesis.

Maternal RNA Transcript Epigenetically Regulates Gene Expression

University of Toronto ♦ Published in Science, September 2, 2011

RNA can function in a number of ways above and beyond acting as a messenger between DNA and the translational machinery found in the cytoplasm. Researchers studying sex determination in C. elegans recently showed that expression of a wild-type allele controlling sex-determination, fem-1, can be regulated by a maternal fem-1 RNA transcript in the germ line. In C. elegans, the nematode worm frequently used as a model organism in studies of genetics, expression of the fem-1 gene is required for male development. In this study, females engineered to express deletions of the fem-1 gene at both alleles gave rise to offspring that exhibited a strong bias towards the female sex in their germ line. Researchers were able to rescue this defect in progeny by injecting a non-coding fem-1 RNA into the maternal germ line. Because the defect is heritable, scientists postulate that fem-1 is typically repressed epigenetically, and that a maternal fem-1 RNA transcript acts to block repression of the wild-type fem-1 gene allowing males to be produced under normal circumstances.

Friday Science Review: September 2, 2011

Functional Validation of Cancer Stem Cell Theory

Ontario Cancer Institute ♦ University of Toronto ♦ Hospital for Sick Children ♦ McMaster University ♦ others..

Published in Nature Medicine, August 28th, 2011

John Dick’s lab has begun functionally validating the cancer stem cell theory in a mouse model and created the closest thing we have to a true leukemia stem cell (LSC) signature. The cancer stem cell theory operates under the premise that not all cells in a tumour can support malignant growth. Instead, only a small, and rare subset of cells at the top of a complex hierarchy is able to sustain the life of a tumour.

Researchers initially attempted to identify cancer stem cells through transplantation into xenograft models. Those fractions that could promote and sustain tumour growth were isolated and analyzed in order to create a cancer stem cell fingerprint. However, it has been discovered that the mouse xenograft models used to create these fingerprints were not sensitive enough. As a result, some cancer stem cells have gone unnoticed.

In order to ensure that the CSC characteristics identified through these experiments are clinically meaningful, they must be linked to patient outcome and survival. This is the first study to take such a robust approach to confirming CSC function, setting a precedent for future experiments in the CSC field. To illustrate how this can be achieved, researchers analyzed fractions of cells from acute myeloid leukemia (AML) tumours from 16 different patients.

The process began by creating four populations of AML cells using the major LSC surface markers (CD34, CD38). These populations were functionally validated through transplantation into a very sensitive xenograft mouse model. Functionally defined LSCs (tumour forming) were subsequently analyzed using global gene expression analysis. Bioinformatic analysis was then utilized to compare 25 LSC-enriched fractions to 29 fractions without LSCs.

Despite the fact that AML samples exhibited different karyotypes and patients were of varying backgrounds (French, British, American), this comparison generated a common LSC signature composed of 42 genes. This signature was then compared to a hematopoietic stem cell (HSC) signature derived from cord blood by similar functional analysis. As could be expected, the genetic profile of LSCs derived from the AML cell lines was quite similar to that of the HSC profile derived from cord blood stem cells; the differences in the LSC and HSC signatures representing genetic targets for treating AML.

The true testament to the value of this study is illustrated by the tests for clinical relevance that followed the formation of LSC and HSC signatures. Correlations between the LSC/HSC signatures and clinical outcome were evaluated using three comprehensive, clinically annotated, gene expression sets. Researchers found a significant negative correlation between complete remission and overall survival, and high expression of the LSR and HSC signatures.

This eloquent work by John Dick’s lab shows us that strong connections can be made between CSC signatures and clinical outcome. Researchers studying other cancer stem cell types should use this study as a model in which to investigate their identity and clinical relevance.


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