There is an increasing demand for new cholesterol-lowering therapies in addition to existing treatments (e.g. targeting statins). The pharmacological inhibition of PCSK9-mediated LDLR degradation is becoming very attractive for treating cholesterol-related diseases. But which reliable in vitro assays are available to effectively study “PCSK9-LDLR” interactions ?
Cancer Immunotherapy – Investigate the TIGIT/CD226 Pathway
Fig 1: TIGIT (VSTM3)/CD226 and CD28/CTLA-4 Pathway
Over the past months, we have released a number of posts introducing inhibitor screening assays intended to investigate immuno checkpoint protein interactions, such as PD-1/PD-L1/PD-L2; B7-1/CD28, B7-1/CTLA4; BLTA/HVEM, CD47/SIRPα; GITR/GITRL and many others – for an overview, you might like to read 9 pathway-specific screening assays in Immunotherapy.
Today, I’d like to concentrate on the TIGIT/CD226 pathway, because it acts through a novel mechanism to regulate CD8+ T cell functions within the tumour microenvironment. [Read more…]
New Polyethylene Glycols (PEG) as versatile biochemical linkers
Polyethylene Glycols (aka. PEGs) are biologically inert, non-immunogenic, and hydrophilic molecules. These properties make them very attractive for research and drug discovery applications (ex. Antibody-Drug Conjugation, imaging, enzymatic detection). The aim of this post is to introduce recent developments in the field of PEG technology provided by BroadPharm.
Best methods for Circulation miRNA profiling (cmiRNA)
We need to find biomarkers for prognostic, diagnostic and personalised treatment development. Notably to fight cancers that affect tissues. Since biopsies are invasive, it’s better to look for biomarkers in body fluids. Indeed, a simple blood sample becomes a kind of ‘liquid biopsy’ to reveal tissues affections. For 13 years, increasing interest has been shown for miRNA as biomarkers and it will last for sure. The 2 main reasons are that they are major regulators of cell processes and they are released from tissues into the blood. They are major biomarker candidates in serum and plasma. Thus, these circulating miRNA (cmiRNA) are the best hope for modern medicine. Still, a lot of research has to be done to determine the specific signature for each pathology, and also depending on the patient background. Obviously, cmiRNA profiling is a key step and requires sensitive and reproducible method. Sequencing, qRT-PCR, several kind of microarrays… Let’s explore together what the best approach could be. [Read more…]
Designer Nucleosomes – the next generation of epigenetic substrates!
Fig. 1: Mononucleosome structure
In eukaryotic cells DNA is packaged in nucleosome units called mono-nucleosomes which consist of a segment of DNA called core DNA (147 bp in length) wound around a histone octamer (Fig 1.). Histone octamers are assembled from 2 copies of the the core histones H2A, H2B, H3, and H4. These mono-nucleosomes are connected by linker 80bp-long DNA. A fifth histone type of protein, the so-called linker histone H1, binds to the linker DNA close to the entry and exit of the core DNA and is involved in chromatin compaction (Fig 1.).
Substrates for epigenetic enzyme assays and inhibitor screenings
In the past, native or recombinant nucleosomes, single histone proteins, or histone derived peptides have been available for assays with epigenetic enzymes such as histone methyltransferases or histone acetylases and related screenings for inhibitors of the respective enzymes (for an overview about the products available, you might like to read my recent post Find the best epigenetic enzyme substrate for your needs).
Table 1: Specific histone modifications can be linked to certain diseases and effector proteins (provided by Epicypher).
As some epigenetic enzymes require highly specific substrates, Epicypher has now launched a new product line – Designer Nucleosomes (dNuc). dNUCs are semi-synthetic nucleosomes incorporating specific histone post-translational modifications. These reagents represent a powerful new technology – critical in understanding chromatin biology and for the development of novel drug targets and precision therapeutics. It is known that highly specific histone modifications can be linked to certain diseases (see Table 1). Table 1 liste the dNUCs which are already available, for further information have a look at our list of Designer Nucleosomes. dNUCs serving as substrates for the most relevant epigenetic enzymes will be added to our catalog in the coming months. If you have specific modifications in mind, which which are know to be optimal for your enzyme of interest, please let me know through the form below. Epicypher might already have this designer nucleosome in their pipeline – or might be able to produce it on a customized basis.
To get more insight into the dNuc manufacturing process Epicypher applies, you can download the white paper Not All Designer Nucleosomes are Created Equal: A Tale of Two Cysteines.
The paper compares the two currently used synthetic methods to produce dNUCs, native chemical ligation (NCL) and methyl lysine analog (MLA). The paper shows that NCL – the method used by Epicypher – yields superior nucleosome preparations.
Any questions or comments? Please feel free to contact me with the form below!
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IL-17A pathway – a key target for immunotherapies
Fig 1: Function of IL-17 in diverse processes
Interleukin-17 (IL-17) is a family of 6 closely related cytokines, designated IL-17A-F, that play a central role in mediating inflammation, autoimmunity, and host defense. IL-17 is mainly secreted by a specific subset of T helper cells known as TH17 cells (for an overview see Fig 1). The IL-17 cytokines mediate their biological functions via surface receptors on target cells. IL-17A binds to IL-17 receptor A (IL-17RA), which stimulates the production of other pro-inflammatory cytokines including IL-6 and IL-8. IL-17A and its receptor play a pathogenic role in many inflammatory and autoimmune diseases such as rheumatoid arthritis. IL-17 signaling is also involved in mucosal immunity and host defense against extracellular bacterial and fungal infections (Staph, Candida, Pneumonia, etc.). [Read more…]
Find the best epigenetic enzyme substrate for your needs
Fig. 1: Nucleosome structure
Nucleosomes are basis units of DNA packaging in eukaryotic cells. A core particle (mono-nucleosome) consists of a segment of DNA called core DNA (147 bp in length) wound around a histone octamer (Fig 1.). Histone octamers are made up of 2 copies of the the core histones H2A, H2B, H3, and H4. These mono-nucleosomes are connected by linker 80bp-long DNA. H1 histone, the so-called linker histone, binds to the linker DNA close to the entry and exit of the core DNA and is involved in chromatin compaction (Fig 1.). [Read more…]
CBR-5884 – a Serine biosynthesis inhibitor for cancer research
Metabolic pathways are upregulated in cancer cells to promote their growth and proliferation. The evidence pointing to the requirement of the amino acid serine in tumorigenesis is overwhelming. Serine is required for a large number of anabolic processes including amino acid and lipid biosynthesis. The enzyme 3-phosphoglycerate dehydrogenase (PHGDH) catalyzes the first committed step in cellular serine biosynthesis and is overexpressed in cancer cell lines and tumors.
CBR-5884 – a selective small molecule inhibitor of PHGDH recently discovered
CBR-5884 chemical structure
Very recently, in a joint effort, the laboratories of Cantley, Lyssiotis and Lairson reported the discovery of a selective small molecule inhibitor of PHGDH designated CBR-5884 (1).
This compound inhibits serine biosynthesis in cancer cells and displays selective cytotoxicity to tumor cell lines overexpressing PHGDH. The identification of CBR-5884 as a drug-like inhibitor of serine biosynthesis is a breakthrough in targeting metabolism in cancer drug development. It is an important compound which provides proof of concept that PHGDH is a viable target, and may represent a lead molecule for the development of more potent analogs. In the mean time it serves as an important new tool compound for the study of cellular serine metabolism.
CBR-5884 is available as a research tool from Focus Biomolecules and tebu-bio
Focus Biomolecules has been the first company to make this promising compound available to the market for cancer research studies.
CBR-5884 (cat. nr 10-1588) can be purchased in Europe through tebu-bio. The compound is available in standard sizes (5 mg & 25 mg) or in bulk amounts (upon request).
Interested in testing CBR-5884 in your experimental setup ?
Please contact me through the form below!
Reference:
(1) Identification of a small molecule inhibitor of 3-phosphoglycerate dehydrogenase to target serine biosynthesis in cancers. E Mullarky et al. Proc. Acad. Natl. Sci. USA 2016 113:1778
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Cancer Immunotherapy: Generate your PD-L1 target cell line
Fig 1: Immuno checkpoint proteins on T cell interact with ligands on APCs or cancer cells
In a recent post, I invited you to discover a cell line provided by BPS Bioscience over-expressing the checkpoint receptor PD-1. They have now just released a new kit which allows to generate a PD-L1 and TCR activator over-expressing target cell line. [Read more…]
Cancer immunotherapy: IDO1 inhibitors – reversible or irreversible?
Fig 1: IDO and TDO – Tryptophan Catabolic Pathways
Trpytophan (trp) is an important and essential amino acid that has a variety of functions within the cell. In addition to being incorporated into the polypeptide chain of proteins, various catabolic pathways can produce a number of functional Trp derivatives. Trp is the biosynthetic precursor of the co-factor NAD, a number of antibiotics, and the neurotransmitters serotonin and melatonin.
The factors regulating the fate of Trp in the cell have yet to be fully elucidated, but likely involve specific enzymes that may vary in expression levels or with the cell type (Fig 1 – Shown is a depiction of two important tryptophan catabolic pathways and the enzymes that participate in the process). [Read more…]