Epothilone A

Catalog No.S1297 Batch:S129701

Technical Data

Formula	C₂₆H₃₉NO₆S
Molecular Weight	493.66	CAS No.	152044-53-6
Solubility (25°C)*	In vitro	DMSO	99 mg/mL (200.54 mM)
		Ethanol	99 mg/mL (200.54 mM)
		Water	Insoluble
* <1 mg/ml means slightly soluble or insoluble. * Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations. * Room temperature shipping (Stability testing shows this product can be shipped without any cooling measures.)

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Biological Activity

Description

Epothilone A is a paclitaxel-like microtubule-stabilizing agent with EC_0.01 of 2 μM.

Targets

Tubulin ^[1]

2 μM(EC0.01)

In vitro

Epothilone A, discovered from the myxobacterium Sorangium cellulosum, is a Taxol-like microtubule-stabilizing agent that induces tubulin polymerization, leading to cell cycle arrest at the G2-M transition, cytotoxicity, and apoptosis. Epothilone A potently inhibits cell proliferation in HCT116 cells, with IC50 of 4.4 nM. ^[1] Epothilone A also displays cytotoxicity in KB3-1, KBV-1, Hela, and Hs578T cells, with IC50 values ranging from 13 nM to 160 nM. Epothilone A is more water soluble than Taxol and competes with Taxol in binding with microtubules, with IC50 of 2.3 μM. ^[2] However, both Epothilone A and Taxol don't share a common pharmacophore and exploits the tubulin-binding pocket uniquely and independently. ^[3] Recently, it is found that microbiological transformation of Epothilone A by Aspergillus niger AS 3.739 yields several metabolites that is also toxic to MCF-7 cells, but with much higher IC50 values. ^[4]

Protocol (from reference)

Kinase Assay:^{^[1]}	Tubulin polymerization assay Calf brain microtubule proteins (MTP) are purified, which includes approximately 15%–20% microtubule associated proteins. The buffer (MES buffer) used for the Epothilone A-microtubule studies contains 0.1 M 2-morpholinoethanesulfonic acid (MES), 1 mM EGTA, 0.5 mM MgCl₂, and 3 M glycerol at pH 6.6. Samples for electron microscopy are placed on carbon-over-Parlodion-coated grids (300 mesh) and negatively stained with 2% uranyl acetate. Microtubule assembly in the presence or absence of Epothilone A is monitored spectrophotometrically by using a spectrophotometer equipped with a thermostatically regulated liquid circulator. The temperature is held at 35 °C and changes in turbidity (representative of polymer mass) are monitored at 350 nm. Effective concentration (EC_0.01), defined as the interpolated concentration capable of inducing an initial slope of 0.01 OD/min rate, is calculated using the formula EC_0.01 = concentration/slope and expressed as the mean with standard deviation obtained from three different concentrations.
Cell Assay:^{^[2]}	Cell lines KB3-1, KBV-1, Hela, and Hs578T cells Concentrations 0–2 μM Incubation Time 24 hours for mitotic arrest or 72 hours for cytotoxicity Method For mitotic block and aberrant mitosis, cells are plated either in 48-well plates (for trypan blue and cell counting) or onto coverslips. After 24 hours, cells are treated with Epothilone A and are scored at regular intervals. For the cytotoxicity analysis, cells are counted and scored as trypan blue positive or negative. Concurrently, coverslips and aliquots of cells in the culture supernatant are fixed and stained with Hoechst 33342 in PBS. These cells are scored for cells blocked at the G2-M transition and aberrant mitosis.

Kinase Assay:^{^[1]}

Tubulin polymerization assay
Calf brain microtubule proteins (MTP) are purified, which includes approximately 15%–20% microtubule associated proteins. The buffer (MES buffer) used for the Epothilone A-microtubule studies contains 0.1 M 2-morpholinoethanesulfonic acid (MES), 1 mM EGTA, 0.5 mM MgCl₂, and 3 M glycerol at pH 6.6. Samples for electron microscopy are placed on carbon-over-Parlodion-coated grids (300 mesh) and negatively stained with 2% uranyl acetate. Microtubule assembly in the presence or absence of Epothilone A is monitored spectrophotometrically by using a spectrophotometer equipped with a thermostatically regulated liquid circulator. The temperature is held at 35 °C and changes in turbidity (representative of polymer mass) are monitored at 350 nm. Effective concentration (EC_0.01), defined as the interpolated concentration capable of inducing an initial slope of 0.01 OD/min rate, is calculated using the formula EC_0.01 = concentration/slope and expressed as the mean with standard deviation obtained from three different concentrations.

Cell Assay:^{^[2]}

Cell lines
KB3-1, KBV-1, Hela, and Hs578T cells
Concentrations
0–2 μM
Incubation Time
24 hours for mitotic arrest or 72 hours for cytotoxicity
Method
For mitotic block and aberrant mitosis, cells are plated either in 48-well plates (for trypan blue and cell counting) or onto coverslips. After 24 hours, cells are treated with Epothilone A and are scored at regular intervals. For the cytotoxicity analysis, cells are counted and scored as trypan blue positive or negative. Concurrently, coverslips and aliquots of cells in the culture supernatant are fixed and stained with Hoechst 33342 in PBS. These cells are scored for cells blocked at the G2-M transition and aberrant mitosis.

References

+ Expand

Selleck's Epothilone A has been cited by 4 publications

In vitro human cell-based aneugen molecular mechanism assay [ Environ Mol Mutagen, 2022, 63(3):151-161]	PubMed: 35426156
Murine- and Human-Derived Autologous Organoid/Immune Cell Co-Cultures as Pre-Clinical Models of Pancreatic Ductal Adenocarcinoma [ Cancers (Basel), 2020, 12(12)E3816]	PubMed: 33348809
Mebendazole is unique among tubulin-active drugs in activating the MEK-ERK pathway [ Sci Rep, 2020, 10(1):13124]	PubMed: 32753665
Aneugen Molecular Mechanism Assay: Proof of Concept with 27 Reference Chemicals [ Toxicol Sci, 2019, 10.1093/toxsci/kfz123]	PubMed: 31132080

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