Names | |
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Preferred IUPAC name (1R,4R,5S)-4-(2-Chloroethyl)-1-{(S)-[(1S)-cyclohex-2-en-1-yl](hydroxy)methyl}-5-methyl-6-oxa-2-azabicyclo[3.2.0]heptane-3,7-dione | |
Other names Marizomib; NPI-0052 | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C15H20ClNO4 | |
Molar mass | 313.781 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Salinosporamide A (Marizomib) is a potent proteasome inhibitor being studied as a potential anticancer agent. It entered phase I human clinical trials for the treatment of multiple myeloma, only three years after its discovery in 2003. [1] [2] This marine natural product is produced by the obligate marine bacteria Salinispora tropica and Salinispora arenicola , which are found in ocean sediment. Salinosporamide A belongs to a family of compounds, known collectively as salinosporamides, which possess a densely functionalized γ-lactam-β-lactone bicyclic core.
Salinosporamide A was discovered by William Fenical and Paul Jensen from Scripps Institution of Oceanography in La Jolla, CA. In preliminary screening, a high percentage of the organic extracts of cultured Salinispora strains possessed antibiotic and anticancer activities, which suggests that these bacteria are an excellent resource for drug discovery. Salinispora strain CNB-392 was isolated from a heat-treated marine sediment sample and cytotoxicity-guided fractionation of the crude extract led to the isolation of salinosporamide A. Although salinosporamide A shares an identical bicyclic ring structure with omuralide, it is uniquely functionalized. Salinosporamide A displayed potent in vitro cytotoxicity against HCT-116 human colon carcinoma with an IC50 value of 11 ng mL-1. This compound also displayed potent and highly selective activity in the NCI's 60-cell-line panel with a mean GI50 value (the concentration required to achieve 50% growth inhibition) of less than 10 nM and a greater than 4 log LC50 differential between resistant and susceptible cell lines. The greatest potency was observed against NCI-H226 non-small cell lung cancer, SF-539 brain tumor, SK-MEL-28 melanoma, and MDA-MB-435 melanoma (formerly misclassified as breast cancer [3] ), all with LC50 values less than 10 nM. Salinosporamide A was tested for its effects on proteasome function because of its structural relationship to omuralide. When tested against purified 20S proteasome, salinosporamide A inhibited proteasomal chymotrypsin-like proteolytic activity with an IC50 value of 1.3 nM. [4] This compound is approximately 35 times more potent than omuralide which was tested as a positive control in the same assay. Thus, the unique functionalization of the core bicyclic ring structure of salinosporamide A appears to have resulted in a molecule that is a significantly more potent proteasome inhibitor than omuralide. [1]
Salinosporamide A inhibits proteasome activity by covalently modifying the active site threonine residues of the 20S proteasome.[ citation needed ]
It was originally hypothesized that salinosporamide B was a biosynthetic precursor to salinosporamide A due to their structural similarities.[ citation needed ]
It was thought that the halogenation of the unactivated methyl group was catalyzed by a non-heme iron halogenase. [5] [6] Recent work using 13C-labeled feeding experiments reveal distinct biosynthetic origins of salinosporamide A and B. [5] [7]
While they share the biosynthetic precursors acetate and presumed β-hydroxycyclohex-2'-enylalanine (3), they differ in the origin of the four-carbon building block that gives rise to their structural differences involving the halogen atom. A hybrid polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) pathway is most likely the biosynthetic mechanism in which acetyl-CoA and butyrate-derived ethylmalonyl-CoA condense to yield the β-ketothioester (4), which then reacts with (3) to generate the linear precursor (5).
The first stereoselective synthesis was reported by Rajender Reddy Leleti and E. J.Corey. [8] Later several routes to the total synthesis of salinosporamide A have been reported. [8] [9] [10] [11]
In vitro studies using purified 20S proteasomes showed that salinosporamide A has lower EC50 for trypsin-like (T-L) activity than does bortezomib. In vivo animal model studies show marked inhibition of T-L activity in response to salinosporamide A, whereas bortezomib enhances T-L proteasome activity.
Initial results from early-stage clinical trials of salinosporamide A in relapsed/refractory multiple myeloma patients were presented at the 2011 American Society of Hematology annual meeting. [12] Further early-stage trials of the drug in a number of different cancers are ongoing. [13]
Bortezomib, sold under the brand name Velcade among others, is an anti-cancer medication used to treat multiple myeloma and mantle cell lymphoma. This includes multiple myeloma in those who have and have not previously received treatment. It is generally used together with other medications. It is given by injection.
Proteasome inhibitors are drugs that block the action of proteasomes, cellular complexes that break down proteins. They are being studied in the treatment of cancer; and three are approved for use in treating multiple myeloma.
Oleocanthal is a phenylethanoid, or a type of natural phenolic compound found in extra-virgin olive oil. It appears to be responsible for the burning sensation that occurs in the back of the throat when consuming such oil. Oleocanthal is a tyrosol ester and its chemical structure is related to oleuropein, also found in olive oil.
Betulinic acid is a naturally occurring pentacyclic triterpenoid which has antiretroviral, antimalarial, and anti-inflammatory properties, as well as a more recently discovered potential as an anticancer agent, by inhibition of topoisomerase. It is found in the bark of several species of plants, principally the white birch from which it gets its name, but also the ber tree, selfheal, the tropical carnivorous plants Triphyophyllum peltatum and Ancistrocladus heyneanus, Diospyros leucomelas, a member of the persimmon family, Tetracera boiviniana, the jambul, flowering quince, rosemary, and Pulsatilla chinensis.
Lycorine is a toxic crystalline alkaloid found in various Amaryllidaceae species, such as the cultivated bush lily, surprise lilies (Lycoris), and daffodils (Narcissus). It may be highly poisonous, or even lethal, when ingested in certain quantities. Regardless, it is sometimes used medicinally, a reason why some groups may harvest the very popular Clivia miniata.
Nereus Pharmaceuticals was a pharmaceutical company focused on the development of natural products from marine microbial and other natural sources into small molecule human therapeutics. The major disease area addressed by Nereus is cancer. Nereus was purchased by Triphase Research and Development in 2012.
Indolocarbazoles (ICZs) are a class of compounds that are under current study due to their potential as anti-cancer drugs and the prospective number of derivatives and uses found from the basic backbone alone. First isolated in 1977, a wide range of structures and derivatives have been found or developed throughout the world. Due to the extensive number of structures available, this review will focus on the more important groups here while covering their occurrence, biological activity, biosynthesis, and laboratory synthesis.
Kendomycin is an anticancer macrolide first isolated from Streptomyces violaceoruber. It has potent activity as an endothelin receptor antagonist and anti-osteoporosis agent. It also has strong cytotoxicity against various tumor cell lines.
Carfilzomib, sold under the brand name Kyprolis, is an anti-cancer medication acting as a selective proteasome inhibitor. Chemically, it is a tetrapeptide epoxyketone and an analog of epoxomicin. It was developed by Onyx Pharmaceuticals.
Callystatin A is a polyketide natural product from the leptomycin family of secondary metabolites. It was first isolated in 1997 from the marine sponge Callyspongia truncata which was collected from the Goto Islands in the Nagasaki Prefecture of Japan by the Kobayashi group. Since then its absolute configuration has been elucidated and callystatin A was discovered to have anti-fungal and anti-tumor activities with extreme potency against the human epidermoid carcinoma KB cells (IG50 = 10 pg/ml) and the mouse lymphocytic leukemia Ll210 cells (IG50 = 20 pg/ml).
The salinosporamides are a group of closely related chemical compounds isolated from marine bacteria in the genus Salinispora. They possess a densely functionalized γ-lactam-β-lactone bicyclic core.
Cylindrocyclophanes are a class of cyclophane, a group of aromatic hydrocarbons composed of two benzene rings attached in a unique structure. Cylindrocyclophanes were the first cyclophanes found in nature, isolated from a species of cyanobacteria, and have proven to be an interesting group of compounds to study due to their unusual molecular structure and intriguing biological possibilities, especially its cytotoxicity to some cancer cell lines.
Fellutamides are tripeptide derivatives from Penicillium fellutanum and other fungi. They are potent proteasome inhibitor that stimulates nerve growth factor synthesis in vitro.
Salinispora tropica is an obligate marine actinomycete bacterium species. It produces salinosporamide A and salinosporamide B, potential anti-cancer agents, as well as the polycyclic macrolides sporolide A and B.
Eudistomins are β-carboline derivatives, isolated from ascidians, like Ritterella sigillinoides, Lissoclinum fragile, or Pseudodistoma aureum.
Salinispora is a genus of obligately aerobic, gram-positive, non-acid-fast bacteria belonging to the family of Micromonosporaceae. They are heterotrophic, non-motile, and obligately grow under high osmotic/ionic-strength conditions. They are the first identified genus of gram-positive bacteria which has a high osmotic/ionic-strength requirement for survival. They are widely abundant in tropical marine sediments and were first identified in 2002. This genus of bacteria has potential biotechnological significance due to their production of novel secondary metabolites which can be used pharmaceutically.
Dideoxyverticillin A, also known as (+)-11,11′-dideoxyverticillin A, is a complex epipolythiodioxopiperazine initially isolated from the marine fungus Penicillium sp. in 1999. It has also been found in the marine fungus Bionectriaceae, and belongs to a class of naturally occurring 2,5-diketopiperazines.
Onnamide A is a bioactive natural product found in Theonella swinhoei, a species of marine sponge whose genus is well known for yielding a diverse set of biologically active natural products, including the swinholides and polytheonamides. It bears structural similarities to the pederins, a family of compounds known to inhibit protein synthesis in eukaryotic cells. Onnamide A and its analogues have attracted academic interest due to their cytotoxicity and potential for combating the growth and proliferation of cancer cells.
Steroidal aromatase inhibitors are a class of drugs that are mostly used for treating breast cancer in postmenopausal women. High levels of estrogen in breast tissue increases the risk of developing breast cancer and the enzyme aromatase is considered to be a good therapeutic target when treating breast cancer due to it being involved in the final step of estrogen biosynthetic pathway and also its inhibition will not affect production of other steroids. Aromatase Inhibitors are classified into two categories based on their structure, nonsteroidal and steroidal; the latter resemble the structure of androstenedione. Steroidal aromatase inhibitors irreversibly inhibit the enzyme by binding covalently to the binding site of aromatase so the substrate cannot access it.
Oprozomib is an orally active second-generation proteasome inhibitor developed by Proteolix, which was acquired by Onyx Pharmaceuticals, an Amgen subsidiary, in 2009. It selectively inhibits chymotrypsin-like activity of both the constitutive proteasome (PSMB5) and immunoproteasome (LMP7).