Paclitaxel is an antineoplastic drug used for the treatment of breast, lung and ovarian cancers and Kaposi’ sarcoma. It targets the microtubules in cancer cells. Microtubules are polymers of alpha and beta tubulin (the building block of microtubules) which form part of the skeleton and provide support and shape to cells. It is involved in many important cellular processes such as cellular transport and cell division. Paclitaxel is administered intravenously, and enters the cancer cell via solute carrier organic anion transporter family member 1B3. In the cytosol, it binds to beta-tubulin and is incorporated into the microtubule during microtubule polymerization. The paclitaxel-microtubule complex promotes stabilization of the microtubule structure preventing its disassembly. This prevents the dynamic function of microtubules by preventing their shortening and lengthening, therefore, the cell is unable to use its cytoskeleton in a flexible manner. This effect on the microtubules inhibit the cell cycle, specifically, phases G2 and M, and as a result, cell replication is prevented. This prevents growth and progression of cancer in patients. Side effects from taking paclitaxel may include bone marrow suppression, hypersensitivity reactions, alopecia, nausea and vomiting, peripheral neuropathy, myalgia, weakness, arthralgia, mucositis and diarrhea.

Paclitaxel Pathway References