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Cortistatins
The cortistatins are a group of steroidal alkaloids first isolated in 2006 from the marine sponge '' Corticium simplex''. The cortistatins were first discovered in a search for naturally occurring compounds that inhibit proliferation of human umbilical vein endothelial cells ( HUVECs), with cortistatin A being the most potent compound in the class. The Shair group at Harvard along with collaborators have shown that cortistatin A is a highly potent and selective inhibitor of CDK8 and CDK19, the kinases that associate with Mediator complex. Out of 386 kinases evaluated, cortistatin A only inhibited CDK8 and CDK19, revealing that it is among the most selective kinase inhibitors. It was also shown that cortistatin A potently inhibits growth of acute myeloid leukemia cells and AML in two in vivo mouse models. Identification of dominant drug-resistant alleles of CDK8 and CDK19 demonstrate that these kinases mediate the activity of cortistatin A in AML cells. Thus, inhibition of CDK8 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDK8
Cell division protein kinase 8 is an enzyme that in humans is encoded by the ''CDK8'' gene. Function The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK8 and cyclin C associate with the Mediator (coactivator), mediator complex and regulate transcription (genetics), transcription by several mechanisms. CDK8 binds to and/or phosphorylates several transcription factors, which can have an activating or inhibitory effect on transcription factor function. CDK8 phosphorylates the Notch signaling pathway, Notch intracellular domain, Sterol regulatory element-binding protein, SREBP, and STAT1 S727. CDK8 also inhibits transcriptional activation by influencing Proteasome, turnover of subunits in the mediator complex tail module. In addition, CDK8 influences binding of RNA polymerase II to the mediator complex. Clinical significance CDK8 is a colorectal cancer oncogene: the ''CDK8'' gene is amplified in human colorectal tumors, activati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroidal Alkaloid
Steroidal alkaloids have organic ring backbones which feature nitrogen-based functional groups. More specifically, they are distinguished by their tetracyclic cyclopentanophenanthrene backbone that marks their close relationship with sterols. They fall in two major categories: Solanum alkaloids and Veratrum alkaloids. A Steroidal alkaloid has also been found in ''Chonemorpha fragrans'' (Frangipani vine), 'chonemorphine' was used to treat intestinal infections in Wistar rats. (Chatterjee DK et al (1987) Parasitol Res 74, 1, 30-33). ''Solanum'' alkaloids These compounds generally appear as their corresponding glycoside in plants of the genus ''Solanum''. ''Solanum'' includes plants like potatoes, tomatoes, and various nightshades Starting with cholesterol, the biosynthesis of these compounds follow a similar general mechanism including hydroxylation, oxidation, and transamination before differentiating. Alkaloids found in these plants include chaconine, solanine, solasodine, tom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, heter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticium Simplex
{{Genus disambiguation ...
''Corticium'' may refer to two different genera: * ''Corticium'' (fungus), a genus of fungi * ''Corticium'' (sponge), a genus of sea sponges in the family Plakinidae Plakinidae is a family of marine sponges. It is composed of seven genera: Plakinidae and Oscarellidae are the two families that compose the fourth and smallest class of the porifera phylum, Homoscleromorpha. * '' Aspiculophora'' Ruiz, Muricy, L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Umbilical Vein Endothelial Cell
Human umbilical vein endothelial cells (HUVECs) are cells derived from the endothelium of veins from the umbilical cord. They are used as a laboratory model system for the study of the function and pathology of endothelial cells (e.g., angiogenesis). They are used due to their low cost, and simple techniques for isolating them from umbilical cords, which are normally resected after childbirth. HUVECs were first isolated and cultured ''in vitro'' in the 1970s by Jaffe and others. Jiménez, N., Krouwer, V. & Post, J. A new, rapid and reproducible method to obtain high quality endothelium in vitro. Cytotechnology 65, 1-14 (2012). HUVECs can be easily made to proliferate in a laboratory setting. Like human umbilical artery endothelial cells they exhibit a cobblestone phenotype when lining vessel walls. Inhibition of the sirtuin protein sirtuin 1 (SIRT1) in HUVECs has been shown to induce cellular senescence. Conversely, overexpression of SIRT1 in HUVECs has been shown to inhibit cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Kinase Inhibitor
A protein kinase inhibitor is a type of enzyme inhibitor that blocks the action of one or more protein kinases. Protein kinases are enzymes that phosphorylate (add a phosphate, or PO4, group) to a protein and can modulate its function. The phosphate groups are usually added to serine, threonine, or tyrosine amino acids on the protein: most kinases act on both serine and threonine, the tyrosine kinases act on tyrosine, and a number (dual-specificity kinases) act on all three. There are also protein kinases that phosphorylate other amino acids, including histidine kinases that phosphorylate histidine residues. Phosphorylation regulates many biological processes, and protein kinase inhibitors can be used to treat diseases due to hyperactive protein kinases (including mutant or overexpressed kinases in cancer) or to modulate cell functions to overcome other disease drivers. Clinical use Kinase inhibitors such as dasatinib are often used in the treatment of cancer and inflammation. So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Myeloid Leukemia
Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cell production. Symptoms may include feeling tired, shortness of breath, easy bruising and bleeding, and increased risk of infection. Occasionally, spread may occur to the brain, skin, or gums. As an acute leukemia, AML progresses rapidly, and is typically fatal within weeks or months if left untreated. Risk factors include smoking, previous chemotherapy or radiation therapy, myelodysplastic syndrome, and exposure to the chemical benzene. The underlying mechanism involves replacement of normal bone marrow with leukemia cells, which results in a drop in red blood cells, platelets, and normal white blood cells. Diagnosis is generally based on bone marrow aspiration and specific blood tests. AML has several subtypes for which treatments and outcomes may vary. The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-enhancer
In genetics, a super-enhancer is a region of the mammalian genome comprising multiple enhancers that is collectively bound by an array of transcription factor proteins to drive transcription of genes involved in cell identity. Because super-enhancers are frequently identified near genes important for controlling and defining cell identity, they may thus be used to quickly identify key nodes regulating cell identity. Enhancers have several quantifiable traits that have a range of values, and these traits are generally elevated at super-enhancers. Super-enhancers are bound by higher levels of transcription-regulating proteins and are associated with genes that are more highly expressed. Expression of genes associated with super-enhancers is particularly sensitive to perturbations, which may facilitate cell state transitions or explain sensitivity of super-enhancer—associated genes to small molecules that target transcription. History The regulation of transcription by enhancers h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Replication
Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm. Viral production / replication Viruses multiply only in living cells. The host cell must provide the energy and synthetic machinery and the low- molecular-weight precursors for the synthesis of viral proteins and nucleic acids. The virus replication occurs in seven stages, namely; # Attachment # Entry, # Uncoating, # Transcription / mRNA production, # Synthesis of virus components, # Virion assembly and # Release (Liberation Stage). Attachment It is the first step of viral replication ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tat (HIV)
In molecular biology, Tat is a protein that is encoded for by the ''tat'' gene in HIV-1. Tat is a regulatory protein that drastically enhances the efficiency of viral transcription. Tat stands for "Trans-Activator of Transcription". The protein consists of between 86 and 101 amino acids depending on the subtype. Tat vastly increases the level of transcription of the HIV dsDNA. Before Tat is present, a small number of RNA transcripts will be made, which allow the Tat protein to be produced. Tat then binds to cellular factors and mediates their phosphorylation, resulting in increased transcription of all HIV genes, providing a positive feedback cycle. This in turn allows HIV to have an explosive response once a threshold amount of Tat is produced, a useful tool for defeating the body's response. Tat also appears to play a more direct role in the HIV disease process. The protein is released by infected cells in culture, and is found in the blood of HIV-1 infected patients. It can b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
