The Cross-Border Biotech Blog

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Tag Archives: PI3K

Friday Science Review: March 12, 2010

Good viruses, bad viruses, biomarkers and protein structures in this week’s research highlights…

Biomarker for Hodgkin’s Lymphoma Subset: Using a high-throughput genomic approach to associate gene expression profile with treatment outcomes for Hodgkin lymphoma, researchers identified an overexpression of genes typically expressed by macrophages in samples from patients who had experienced a relapse after treatment.  This was confirmed histologically by looking at stained tissue samples and tallying the number of macrophages – high numbers of macrophages are associated with treatment resistance in Hodgkin lymphoma.  About 25% of patients fall into this category where a biomarker test could shuttle them into a more aggressive or experimental treatment option and may prevent them from being exposed to the side effects of primary treatments that are likely to fail.  The study, led by B.C. Cancer Agency researcher Dr. Randy Gascoyne, is reported in The New England Journal of Medicine with an editorial that is touting this as the “breakthrough we have been looking for.”

Immune System Boost for HIV Patients:  A very important molecular discovery may give a boost to restoring immune function in HIV infected patients.  Renowned HIV scientist, Dr. Rafick-Pierre Sékaly, and his cross-border research teams at the Université de Montréal and Vaccine and Gene Therapy Institute of Florida identified that the protein PD-1 is up-regulated by the release of bacterial products from the gut.  Another factor, IL-10, is subsequently increased and together this is what shuts down the CD4+ T-cell immune system in HIV patients.  Therefore, the scientists suggest that new immunotherapies should aim to block PD-1 and IL-10 to help restore the debilitated immune system in HIV infected patients.  The research article appears in this week’s Nature Medicine.

Not All Viruses are Bad: The ubiquitous reovirus has oncolytic actions against different types of cancer when used as a therapeutic approach.  Now, prostate cancer may be added to the growing list of cancers, which includes ovarian, breast, pancreatic and gliomas, that may be treated with a reovirus based strategy.  In fact, the Calgary-based Oncolytics Biotech Inc. technology platform and pipeline are based on the reovirus and contributed to the prostate study.  In the prostate cancer clinical study, a viral concoction was injected into prostate cancer nodules and three weeks later, the prostates were resected.  There was evidence of cancer cell death and overall, the procedure was deemed safe with only mild side effects experienced by the patients.  The success of this pilot study should draw interest to expand the clinical trial novel treatment for prostate cancer.  Dr. Donald Morris led the research and medical team at the University of Calgary and reports the study in Cancer Research.

Having Fun with Names: This study provides more molecular and structural details than you probably need to know but I want to point out the cool protein domain name: Really Interesting New Gene or RING domain.  It is an important component of a group of proteins that regulate the potent oncogene called eIF4E (eukaryotic translation initiation factor).  The details of the Université de Montréal study are described in the Proceedings of the National Academy of Sciences.

Pump It Up: Another structural study that I want to point out because of its importance: the V-ATPase.  This is a membrane proton pump that controls the acidity of the cellular environment and can play critical roles for the cell in promoting a diseased state.  SickKids Research Instiute scientist, Dr. John Rubinstein explains “In some types of cancer, the pumps are “hijacked” to acidify the external environment of tumours, allowing the cancer to invade surrounding tissues and spread throughout the body.  The cells that take up bone minerals also use V-ATPases to dissolve bone, a process that must be limited in treating osteoporosis.”  More details on the study are found here in the Proceedings of the National Academy of Sciences.

Paradoxical Signalling Interaction: The phosphatidylinositol 3-kinase (PI3K) signaling pathway is a well studied signaling module and its aberrant activity is implicated in a number of diseases including cancer.  It is also the target of a handful of therapeutic drugs currently under study or in trials.  However, the new study led by Dr. Deborah Anderson at the Saskatchewan Cancer Agency throws a new twist into the pathway.  Their data identifies a paradoxical interaction between the p85 regulatory subunit of PI3K and the PTEN phosphatase enzyme since these two enzymes have opposing actions.  This is certainly food for thought for researchers in this field to rethink their signalling models.  A recent news article headlines this study as the “on switch” for cancer cell growth but it is really a much more complicated puzzle than that.  The data is presented in the early edition of the Proceedings of the National Academy of Sciences.

Friday Science Review: November 20, 2009

Intestinal disease genomics and how hedgehogs cause arthritis…

Genetic Clues to ‘Belly Aches’ in Children: The largest genomic investigation into early onset inflammatory bowel disease (IBD) including Crohn’s disease and ulcerative colitis involved the efforts of an international research team.  In total, genetic information from 3,400 children with IBD and 12,000 healthy children were compared.  This study resulted in the identification of five genetic regions associated with susceptibility to pediatric and adolescent IBD.  The team is now taking a closer look at these regions to try to identify the specific proteins that may explain why or how the disease develops.  Another question that they would like to address is why some individuals develop IBD early whereas others develop it later in life.  Two Toronto researchers, Dr. Anne Griffiths (Sickkids) and Dr. Mark Silverberg (Mount Sinai Hospital), contributed their expertise to the study, which appears in this week’s issue of Nature Genetics.

Colon Cancer Susceptibility Genes: In another intestinal disease research project, scientists noticed that different strains of mice exhibited different levels of resistance or susceptibility to colon cancer induced by a chemical carcinogen.  Using genetic studies, the determining factor was mapped to a specific region in chromosome 3 that they designated as colon cancer susceptibility locus 3 (Ccs3).  Within this region are about 94 known genes and they have identified a subset that are expressed at high levels in the colon.  What is also interesting is that Ccs3 in mice is homologous to regions in human chromosome 1 and 4, which also contain genes known to be associated with inflammatory bowel disease and colorectal cancer.  This mouse model will be a very useful tool for future studies on the pathogenesis of colon cancer.  Dr. Philippe Gros led the research team at McGill University and published the study in the journal Oncogene.

Hedgehogs are Key to Osteoarthritis: An unexpected discovery may hold the key to solving painful osteoarthritic disease.  Elevated expression or activity of a group of proteins called Hedgehog resulted in the development of osteoarthritis in mice.  In simple terms, the balance of this signalling pathway in chondrocyte cells determines whether they go on to make cartilage or bone.  In the animal model of osteoarthritis, Hedgehog levels are high and there is less cartilage being produced from the chrondrocytes.  Obviously, Hedgehog becomes an immediate pharmacologic target for the treatment or prevention of osteoarthritis.  You may find it strange that this study on a disease primarily affecting adults is from The Hospital for Sick Children but it just shows that research is full of surprises and you never know where it may take you!  Dr. Benjamin Alman and his research team reported their study in the online edition of Nature Medicine.

Pathway Signalling Antibody Production: A key signalling pathway required for the efficient production of antibodies was identified recently and verified using knockout mice.  A receptor on T cells called ICOS (Inducible Costimulator) is required for their conversion into a specialized type of T cell called Tfh cells (follicular B helper T cells).  As the name implies, their role is to help B cells make the right antibodies to the target.  Dr. Woong-Kyung Suh’s team at Institut de recherches cliniques de Montréal discovered that ICOS activates an enzyme called phosphoinositide 3-kinase (PI3K), which eventually leads to the release of factors that trigger the formation of Tfh cells.  With this knowledge, researchers may find ways to tweak the system to suppress (in autoimmune disease) or enhance (in infectious disease) antibody production as required.  The study is reported in the Proceedings of the National Academy of Sciences.

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