Epothilone B, Free Base (EPO-906, EpoB, Patupilone, 152044-54-7), >99%

LC Laboratories' Product Number E-5500 - Epothilone B, Free Base (EPO-906, EpoB, Patupilone, 152044-54-7), >99% - for research use only. Epothilones A-F are anticancer drugs. They induce microtubule polymerization at submicromolar concentrations and lead to death of cancer cells. Epothilone B possess essentially all the biological effects of taxol both in vitro and in cultured cells. Epothilone B caused cell cycle arrest at the G2-M transition (EC50 = 32 nM for Hela cells and 3 nM for Hs578T), similar to taxol (EC50 = 7 nM for Hela cells and 10 nM for Hs578T). Epothilone B leads to cytotoxicity (EC50 = 40 nM for Hela cells and 6 nM for Hs578T), also similar to taxol (EC50 = 20 nM for Hela cells and 15 nM for Hs578T). However, epothilone B retains a much greater mitotic arrest at the G2-M transition and toxicity against P-glycoprotein-expressing multiple drug resistant KBV-1 cells (EC50 = 92 nM and 58 nM, respectively) than paclitaxel (EC50 = 17 µM and 23 µM, respectively). Two acquired β-tubulin mutations [β274(Thr-->Ile) and β282(Arg-->Gln)] near the taxane binding site exhibit impaired epothilone- and taxane-driven tubulin polymerization. Purified tubulin from parental 1A9 human ovarian carcinoma cells demonstrated paclitaxel-driven increased polymerization while the resistant cell tubulin with a mutation at 270 (Phe --> Val) or 364 (Ala --> Thr) barely polymerized under identical conditions. In contrast, the resistant cells retained sensitivity to epothilone B and the assembly was increased. Epothilone B inhibited the growth of paclitaxel-sensitive human carcinoma cell lines including A549 (lung), NCI-H460 (Lung), HCT-116 (colon), DU145 (prostate), PC-3M (prostate), MDA-MB-231 (breast), BT-20 (breast), ZR-75-1 (breast), T-24 (bladder), and A-431 (epidermoid) with IC50's ranging from 0.13 nM to 0.64 nM. It also inhibited the growth of paclitaxel-resistant human cancer cell lines including CCRF-CEM (leukemia), CCRF-CEM/VBL100, SW620 (colon), SW620AD-300, KB-31, KB-8511, 1A9 (ovarian), 1A9PTX22, MCF-7 (breast), MCF-7/ADR, and HCT-15 (colon) with IC50's of 0.06 nM to 2.9 nM. Diarrhea is the dose-limiting toxicity for epothilone B in clinical trials for patients with lung, ovarian and prostate cancers. Another CAS number previously assigned to epothilone B, 681125-91-7, has been deleted by CAS and is no longer in use.

• Supplier: LC Laboratories
• Product #: E-5500
• Sku #: E-5500_25mg