Monday, 19 June 2017

Cucurbitacin E kháng LNCaP

Cucurbitacin E kháng LNCaP

From Wikipedia, the free encyclopedia
Cucurbitacin E
Skeletal structure of Cucuribitacin E
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard100.038.463
PubChem CID
UNII
Properties
C32H44O8
Molar mass556.76 g/mol
Density1.249 g/cm3
Melting point228 to 232 °C; 442 to 449 °F; 501 to 505 K
Boiling point712.47 °C; 1,314.45 °F; 985.62 K
Hazards
Flash point497.45 °C (927.41 °F; 770.60 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Cucurbitacin E is a biochemical compound from the family of cucurbitacins. These are found in plants which are member of the family Cucurbitaceae, most of them coming from traditional Chinese medicinal plants, but also in other plants such as pumpkins and gourds.
Cucurbitacin E is a highly oxidated steroid consisting of a tetracyclic triterpene. Specific changes on this molecule under certain conditions can generate other types of cucurbitacins such as cucurbitacin I, J, K and L.
It is being investigated as a treatment for many diseases.
Cucumbers belong to the family Cucurbitaceae
Watermelons are a rich source of Cucurbitacin E

Properties[edit]

Anti-inflammatory[edit]

Cucurbitacin E anti-inflammatory activities are proved in vivo and in vitro.[citation needed] It is useful in the treatment of inflammation because of the inhibition of cyclooxygenase and reactive nitrogen species (RNS) but not reactive oxygen species(ROS).[citation needed]
Macrophages are responsible for the production of various cytokines, RNS and ROS, growth factors and chemokines as a response to activation signal such as chemical mediators, cytokines and lipopolysaccharide.[citation needed] Although these molecules have an important role, they can also have damaging effects, like some RNS.[citation needed] Cucurbitacin possesses dose-dependent anti-inflammatory activity related to its inhibition of nitric oxide (an RNS) production in macrophages without affecting the viability of these cells.[citation needed]
As cucurbitacin E doesn't affect normal human liver cells, it may have therapeutic potential and effective treatment for a variety of inflammation mediated diseases.[2]

Antioxidant properties[edit]

Cucurbitacin E glycoside has demonstrated antioxidant and free-radical scavenging properties. Its antioxidant and free-radical scavenging properties were measured by the ability of cucurbitacin glycoside combination (CGC), a combination of cucurbitacin B and E glycosides, to reduce ABTS cation to its original form and also the capacity to inhibit MDA formation originated in the oxidation of linoleic acid. Using electron paramagnetic resonance, it was confirmed that CGC had antioxidant properties because of its capacity for scavenging free radicals, such as: superoxide anion (O2-), hydroxyl radical (OH-) and singlet oxygen. Not all natural antioxidants have strong free-radical scavenging properties against multiple free-radicals.[3]
CGC is being investigated as a treatment for human diseases that are linked to oxidative or free-radical damage such as atherosclerosis, cancer, Alzheimer's disease and diabetes.[4]

Cytostatic[edit]

Cucurbitacin E is an important inhibitor during the S to M phase in the cell mitosis. It causes a reduction of cell multiplication.[citation needed]

Cytotoxicity[edit]

This triterpene can inhibit the phosphorylation of the cofilin protein, a family of actin-binding proteins that disassembles actin filaments.[5][6]
Therefore, Cucurbitacin E can induce to tumoral-cell apoptosis and can also reduce cancer metastasis. It is tested that Cucurbitacin E shows cytotoxicity to:[7]
  • The colon cancer cell line HCT-116
  • The lung cancer cell line NCI-H460
  • The breast cancer cell lines MCF-7 and ZR-75-1
  • The central nervous system tumor cell line SF-268
  • The oral epidermoid carcinoma cell line KB
  • The cervical cancer cell line HeLa
  • The fibrosarcoma cell line HT1080
  • The acute leukemia cell lines U937 and HL-60
  • The prostate cancer cell lines PC, LNCaP and DU145
  • The pancreatic cancer cell line Panc-1
  • The ovarian cancer cell line S-2
  • The bladder cancer cell line T24
  • The hepatic carcinoma cell lines BEL-7402 and HepG2

Anti-angiogenesis[edit]

Cucurbitacin can also inhibit VEGFR2-mediated Jak-STAT3[7] and MAPK signaling pathways. Anti-angiogenesis property of cucurbitacin E was demonstrated in vitro but also in vivo in a chick embryo chorioallantoic membrane and in a mouse corneal angiogenesis model.[citation needed]

Anti-invasion and anti-metastasis[edit]

Cucurbitacin E inhibits the adhesion of cancer cells in type I collagen .[7]

Hepatoprotecive effect[edit]

Cucurbitacin-E protects hepatocytes from CCl4 (carbon tetrachloride), by reducing GPT, GOT, ALP, TP and TBIL serums.[7]

See also[edit]

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Piscarinine kháng LNCaP

Piscarinine kháng LNCaP

From Wikipedia, the free encyclopedia
2D Structure of Piscarinine A and Piscarinine B
Piscarinines are bioactive alkaloid isolates of Penicillium piscarium NKM F-961 [1] and Penicillium piscarium Westling [2] that belong to a class of naturally occurring 2,5-diketopiperazines.[3] The cytotoxic dehydroproline tryptophan derivatives piscarinines A and B were shown to be active against the prostate cancer cell line LNCAP [2] (IC50 values were 2.2 and 1.9 μg/mL for piscarinine A and B, respectively).
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Peptide kháng LNCaP

Identification of a LNCaP-specific binding peptide using phage display.

Peptide kháng LNCaP

From Wikipedia, the free encyclopedia
"Peptides" redirects here. For the journal, see Peptides (journal).
A tetrapeptide (example Val-Gly-Ser-Ala) with green marked amino end (L-Valine) and
blue marked carboxyl end (L-Alanine).
Peptides (from Gr.: πεπτός, peptós "digested"; derived from πέσσειν, péssein "to digest") are biologically occurring short chains of amino acid monomers linked by peptide (amide) bonds.
The covalent chemical bonds are formed when the carboxyl group of one amino acid reacts with the amine group of another. The shortest peptides are dipeptides, consisting of 2 amino acids joined by a single peptide bond, followed by tripeptides, tetrapeptides, etc. A polypeptide is a long, continuous, and unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological oligomers and polymers, alongside nucleic acids, oligosaccharides and polysaccharides, etc.
Peptides are distinguished from proteins on the basis of size, and as an arbitrary benchmark can be understood to contain approximately 50 or fewer amino acids.[1][2] Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule (DNA, RNA, etc.), or to complex macromolecular assemblies.[3] Finally, while aspects of the lab techniques applied to peptides versus polypeptides and proteins differ (e.g., the specifics of electrophoresis, chromatography, etc.), the size boundaries that distinguish peptides from polypeptides and proteins are not absolute: long peptides such as amyloid beta have been referred to as proteins, and smaller proteins like insulin have been considered peptides.
Amino acids that have been incorporated into peptides are termed "residues" due to the release of either a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both, as a water molecule is released during formation of each amide bond.[4] All peptides except cyclic peptides have an N-terminal and C-terminalresidue at the end of the peptide (as shown for the tetrapeptide in the image).

Peptide classes[edit]

Peptides are divided into several classes, depending on how they are produced:
Milk peptides 
Two naturally occurring milk peptides are formed from the milk protein casein when digestive enzymes break this down; they can also arise from the proteinasesformed by lactobacilli during the fermentation of milk.[5]
Ribosomal peptides 
Ribosomal peptides are synthesized by translation of mRNA. They are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins.[6] Since they are translated, the amino acidresidues involved are restricted to those utilized by the ribosome.
However, these peptides frequently have posttranslational modifications such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation and disulfideformation. In general, they are linear, although lariat structures have been observed.[7] More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom.[8]
Nonribosomal peptides 
Nonribosomal peptides are assembled by enzymes that are specific to each peptide, rather than by the ribosome. The most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms.[9] Other nonribosomal peptides are most common in unicellular organisms, plants, and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases.[10]
These complexes are often laid out in a similar fashion, and they can contain many different modules to perform a diverse set of chemical manipulations on the developing product.[11] These peptides are often cyclic and can have highly complex cyclic structures, although linear nonribosomal peptides are also common. Since the system is closely related to the machinery for building fatty acids and polyketides, hybrid compounds are often found. The presence of oxazoles or thiazoles often indicates that the compound was synthesized in this fashion.[12]
Peptones
See also Tryptone
Peptones are derived from animal milk or meat digested by proteolysis.[13] In addition to containing small peptides, the resulting material includes fats, metals, salts, vitamins and many other biological compounds. Peptones are used in nutrient media for growing bacteria and fungi.[14]
Peptide fragments 
Peptide fragments refer to fragments of proteins that are used to identify or quantify the source protein.[15] Often these are the products of enzymatic degradation performed in the laboratory on a controlled sample, but can also be forensic or paleontological samples that have been degraded by natural effects.[16][17]

Peptide synthesis[edit]

Main article: Peptide synthesis
Table of amino acids
Solid-phase peptide synthesis on a rink amide resin using Fmoc-α-amine-protected amino acid

Peptides in molecular biology[edit]

Peptides received prominence in molecular biology for several reasons. The first is that peptides allow the creation of peptide antibodies in animals without the need of purifying the protein of interest.[18] This involves synthesizing antigenic peptides of sections of the protein of interest. These will then be used to make antibodies in a rabbit or mouse against the protein.
Another reason is that peptides have become instrumental in mass spectrometry, allowing the identification of proteins of interest based on peptide masses and sequence.
Peptides have recently been used in the study of protein structure and function. For example, synthetic peptides can be used as probes to see where protein-peptide interactions occur- see the page on Protein tags.
Inhibitory peptides are also used in clinical research to examine the effects of peptides on the inhibition of cancer proteins and other diseases.[19] For example, one of the most promising application is through peptides that target LHRH.[20] These particular peptides act as an agonist, meaning that they bind to a cell in a way that regulates LHRH receptors. The process of inhibiting the cell receptors suggests that peptides could be beneficial in treating prostate cancer. However, additional investigations and experiments are required before the cancer-fighting attributes, exhibited by peptides, can be considered definitive.[21]

Well-known peptide families[edit]

The peptide families in this section are ribosomal peptides, usually with hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and truncated prior to exiting the cell. They are released into the bloodstream where they perform their signaling functions.

Antimicrobial peptides[edit]

Tachykinin peptides[edit]

Main article: Tachykinin peptides

Vasoactive intestinal peptides[edit]

Main article: Secretin family
  • VIP (Vasoactive Intestinal Peptide; PHM27)
  • PACAP Pituitary Adenylate Cyclase Activating Peptide
  • Peptide PHI 27 (Peptide Histidine Isoleucine 27)
  • GHRH 1-24 (Growth Hormone Releasing Hormone 1-24)
  • Glucagon
  • Secretin

Pancreatic polypeptide-related peptides[edit]

  • NPY (NeuroPeptide Y)
  • PYY (Peptide YY)
  • APP (Avian Pancreatic Polypeptide)
  • PPY Pancreatic PolYpeptide

Opioid peptides[edit]

Main article: Opioid peptide

Calcitonin peptides[edit]

Other peptides[edit]

Notes on terminology[edit]

Length:
  • A polypeptide is a single linear chain of many amino acids, held together by amide bonds.
  • A protein consists of one or more polypeptides (more than about 50 amino acids long).
  • An oligopeptide consists of only a few amino acids (between two and twenty).
A tripeptide (example Val-Gly-Ala) with
green marked amino end (L-Valine) and
blue marked carboxyl end (L-Alanine)
Number of amino acids:
  • A monopeptide has one amino acid.
  • A dipeptide has two amino acids.
  • A tripeptide has three amino acids.
  • A tetrapeptide has four amino acids.
  • A pentapeptide has five amino acids.
  • A hexapeptide has six amino acids.
  • A heptapeptide has seven amino acids.
  • An octapeptide has eight amino acids (e.g., angiotensin II).
  • A nonapeptide has nine amino acids (e.g., oxytocin).
  • A decapeptide has ten amino acids (e.g., gonadotropin-releasing hormone & angiotensin I).
  • An undecapeptide (or monodecapeptide) has eleven amino acids, a dodecapeptide (or didecapeptide) has twelve amino acids, a tridecapeptide has thirteen amino acids, and so forth.
  • An icosapeptide has twenty amino acids, a tricontapeptide has thirty amino acids, a tetracontapeptide has forty amino acids, and so forth.
See also: IUPAC numerical multiplier
Function:
  • A neuropeptide is a peptide that is active in association with neural tissue.
  • A lipopeptide is a peptide that has a lipid connected to it, and pepducins are lipopeptides that interact with GPCRs.
  • A peptide hormone is a peptide that acts as a hormone.
  • A proteose is a mixture of peptides produced by the hydrolysis of proteins. The term is somewhat archaic.

Doping in sports[edit]

The term peptide has been used to mean secretagogue peptides and peptide hormones in sports doping matters: secretagogue peptides are classified as Schedule 2 (S2) prohibited substances on the World Anti-Doping Agency (WADA) Prohibited List, and are therefore prohibited for use by professional athletes both in and out of competition. Such secretagogue peptides have been on the WADA prohibited substances list since at least 2008. The Australian Crime Commission cited the alleged misuse of secretagogue peptides in Australian sport including growth hormone releasing peptides CJC-1295, GHRP-6, and GHSR (gene) hexarelin. There is ongoing controversy on the legality of using secretagogue peptides in sports.[26]
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