Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin into protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement.
Paclitaxel, sold under the brand name Taxol among others, is a chemotherapy medication used to treat ovarian cancer, esophageal cancer, breast cancer, lung cancer, Kaposi's sarcoma, cervical cancer, and pancreatic cancer. It is administered by intravenous injection. There is also an albumin-bound formulation.
Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytoskeleton. Microtubules function in many essential cellular processes, including mitosis. Tubulin-binding drugs kill cancerous cells by inhibiting microtubule dynamics, which are required for DNA segregation and therefore cell division.
Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and anti-inflammatory.
Docetaxel, sold under the brand name Taxotere among others, is a chemotherapy medication used to treat a number of types of cancer. This includes breast cancer, head and neck cancer, stomach cancer, prostate cancer and non-small-cell lung cancer. It may be used by itself or along with other chemotherapy medication. It is given by slow injection into a vein.
A spindle poison, also known as a spindle toxin, is a poison that disrupts cell division by affecting the protein threads that connect the centromere regions of chromosomes, known as spindles. Spindle poisons effectively cease the production of new cells by interrupting the mitosis phase of cell division at the spindle assembly checkpoint (SAC). However, as numerous and varied as they are, spindle poisons are not yet 100% effective at ending the formation of tumors (neoplasms). Although not 100% effective, substantive therapeutic efficacy has been found in these types of chemotherapeutic treatments. The mitotic spindle is composed of microtubules that aid, along with regulatory proteins, each other in the activity of appropriately segregating replicated chromosomes. Certain compounds affecting the mitotic spindle have proven highly effective against solid tumors and hematological malignancies.
Stathmin, also known as metablastin and oncoprotein 18 is a protein that in humans is encoded by the STMN1 gene.
Paclitaxel total synthesis in organic chemistry is a major ongoing research effort in the total synthesis of paclitaxel (Taxol). This diterpenoid is an important drug in the treatment of cancer but, also expensive because the compound is harvested from a scarce resource, namely the Pacific yew. Not only is the synthetic reproduction of the compound itself of great commercial and scientific importance, but it also opens the way to paclitaxel derivatives not found in nature but with greater potential.
Vinca alkaloids are a set of anti-mitotic and anti-microtubule alkaloid agents originally derived from the periwinkle plant Catharanthus roseus and other vinca plants. They block beta-tubulin polymerization in a dividing cell.
Epothilones are a class of potential cancer drugs. Like taxanes, they prevent cancer cells from dividing by interfering with tubulin, but in early trials, epothilones have better efficacy and milder adverse effects than taxanes.
Taxus globosa, the Mexican yew, is an evergreen shrub and one of the eight species of yew. The Mexican yew is a rare species, only known to be found in a small number of locations in eastern Mexico, Guatemala, El Salvador and Honduras, and is listed as an endangered species. The Mexican yew is a shrub that grows to an average height of 4.6m. It has large, sharp light green needles growing in ranks on either side of its branches.
Rhizoxin is an antimitotic agent with anti-tumor activity. It is isolated from a pathogenic plant fungus which causes rice seedling blight.
A mitotic inhibitor, microtubule inhibitor, or tubulin inhibitor, is a drug that inhibits mitosis, or cell division, and is used in treating cancer, gout, and nail fungus. These drugs disrupt microtubules, which are structures that pull the chromosomes apart when a cell divides. Mitotic inhibitors are used in cancer treatment, because cancer cells are able to grow through continuous division that eventually spread through the body (metastasize). Thus, cancer cells are more sensitive to inhibition of mitosis than normal cells. Mitotic inhibitors are also used in cytogenetics, where they stop cell division at a stage where chromosomes can be easily examined.
Class III β-tubulin, otherwise known as βIII-tubulin (β3-tubulin) or β-tubulin III, is a microtubule element of the tubulin family found almost exclusively in neurons, and in testis cells. In humans, it is encoded by the TUBB3 gene.
Taxoids are a class of derivatives from taxol, that is, paclitaxel. They were developed for their anticancer chemotherapeutic properties. Taxoids are usually treated as synonymous with taxanes; for example, a major medical dictionary defines the two terms with the same definition phrasing, and in another the phrasing varies slightly but conveys nearly identical meaning.
Abeotaxanes are a class of taxoid molecules with a core 5/7/6 type ring structure. This structure varies from the 6/8/6 or 6/10/6-membered core ring found in conventional taxoids such as paclitaxel or docetaxel. The core carbon skeleton of a normal natural product taxane has a 6-membered A ring, 8-membered B ring and a 6-membered C ring, combined with conventional side chains. It is the side chains that provide most of the activity for regular taxanes. Abeotaxanes are compounds containing 3 altered ring structures, where ring A is 5 members, ring B is 7 members and ring C is 6 members, combined with conventional side chains.
Taccalonolides are a class of microtubule-stabilizing agents isolated from Tacca chantrieri that has been shown to have selective cancer-fighting properties. Other examples of microtubule-stabilizing agents include taxanes and epothilones, both of which prevent cancer cells from dividing by interfering with tubulin. While taxanes like Paclitaxel and docetaxel have been used successfully against breast, ovarian, prostate, and non–small-cell lung cancers, intrinsic and acquired drug resistance limit their anticancer properties. Unlike taxanes, taccalonolides appear to work through a different mechanism of action that does not involve tubulin, although recently isolated taccalonolides AF and AJ have shown tubulin-interaction activity. The discovery of taccalonolides opens up new possibilities to treat cancer cells, especially ones that are taxane or epithilone resistant.
Taxine alkaloids, which are often named under the collective title of taxines, are the toxic chemicals that can be isolated from the yew tree. The amount of taxine alkaloids depends on the species of yew, with Taxus baccata and Taxus cuspidata containing the most. The major taxine alkaloids are taxine A and taxine B although there are at least 10 different alkaloids. Until 1956, it was believed that all the taxine alkaloids were one single compound named taxine.
Sabizabulin is a chemical compound from the group of indole and imidazole derivatives that was first reported in 2012 by Dalton, Li, and Miller. It is being studied as a mitotic inhibitor and chemotherapeutic agent in castration-resistant metastatic prostate cancer and in SARS-CoV-2 (COVID-19) infections.
Taxuspines is a class of taxanes, which are encountered in several species of the genus Taxus.
