Paclitaxel, 25 mg

Available from STEMCELL Technologies, this small molecule inhibitor of microtubule formation, Paclitaxel, was originally isolated as a diterpene alkaloid from the bark of the Pacific Yew tree (Taxus brevifolia). It binds to and stabilizes microtubules, preventing their reorganization during cell division, which leads to cell cycle arrest. The compound exhibits antitumorigenic properties and has been used as a chemotherapeutic compound. Alternative names include NSC 125973 and Taxol™.

The product is supplied as a crystalline solid with a molecular weight of 853.9 g/mol (chemical formula C₄₇H₅₁NO₁₄) and a purity of ≥ 98%. Its CAS number is 33069-62-4. The product is stable at -20°C as supplied and should be protected from prolonged exposure to light. Solubility is limited in aqueous media but reaches ≤ 5 mM in DMSO and ≤ 1.5 mM in absolute ethanol. To prepare a 1 mM stock solution in DMSO, 10 mg should be resuspended in 11.7 mL of DMSO. Stock solutions should be prepared fresh before use, and for cell culture applications the stock solution should be diluted into culture medium immediately before use. Final DMSO concentration should be kept below 0.1% to avoid potential cell toxicity.

Published applications include differentiation research, where the compound inhibits initiation and outgrowth of neurites in vitro through microtubule polymerization, and cancer research, where it inhibits tumor cell growth in a variety of cancer cell lines including cervical (HeLa), lung (A549), breast (MCF-7), colon (HT-29), ovarian (OVG-1), and pancreatic (PC-Sh) carcinomas. It induces abnormal multipolar spindle formation and cell cycle arrest at prophase and G1 in various human cancer cell lines, and initiates apoptosis through multiple mechanisms involving p53-dependent and -independent pathways, BCL-2 family members, cyclin-dependent kinases, p38 MAPK, PKA, and JNK/SAPK. The product is hazardous; users should refer to the Safety Data Sheet. A California Proposition 65 warning applies, as this product can expose users to a chemical known to the State of California to cause birth defects or other reproductive harm. The product is intended for research use only and not for human or animal diagnostic or therapeutic uses unless otherwise stated.