مقالات پذیرفته شده در سومین کنگره بین المللی زیست پزشکی
Biotechnological Taxol Synthesis and signaling pathways in E. coli
Biotechnological Taxol Synthesis and signaling pathways in E. coli
Mehrana Jafari,1,*Azam Ahmadi,2
1. Infectious Diseases Research Center (IDRC), Arak University of medical science. 2. Infectious Diseases Research Center (IDRC), Arak University of medical science.
Introduction: Taxol and related compounds are plant alkaloids isolated from varies Taxus spices, has been approved as a drug for many different types of cancer. Taxol naturally produced in the bark and needles of Taxus spices, but 2 or 3 full growth tree need for cure the person with cancer.
Paclitaxel (commercial name of Taxol) is very Expensive, There are some artificial way to produce it, such as biotechnological synthesis. Biotechnological synthesis is an artificial method for its production. Tissue culture of Taxus species, including T. baccata, T. yunnanensis, T. cuspidate, T. chinensis, T. brevifolia, T. canadensis, and T. globosa using pre-feeding strategies, and using fungal culture inducers.
Taxol and analogs are anticancer drugs that inhibited mitosis by polymerization of tubulin and consequent stabilization of microtubules for its anticancer activities.
Paclitaxel used as valuable anticancer in the treatment of breast cancer, colorectal cancer and squamous cell carcinoma of urinary bladder, head and neck cancers, small-cell and non-small-cell lung cancers (NSCLCs), and AIDS. Also Paclitaxel to treat ovarian, lung, gastro esophageal, endometrial, cervical, prostate cancer, in addition to sarcoma, lymphoma, and leukemia.
Paclitaxel is a tubulin-binding anticancer drugs, which prevent the assembly of tubulin into microtubules, paclitaxel promotes the assembly of tubulin into microtubules and prevents the dissociation of microtubules, blocking cell cycle progression, preventing mitosis, and inhibiting the growth of cancer cells. Paclitaxel antitumor effects were due to mitotic arrest. Mitotic arrest results in either death during mitosis or an abnormal exit from mitosis, without chromosome segregation or cytokinesis, to form a tetraploid G1 cell; this exit is known as mitotic slippage. After slippage, cells can die, arrest, or continue cycling. One popular hypothesis was that mitotic checkpoint responded to mitotic arrest and killed the cell, but some studies state of the mitotic checkpoint does not affect this sensitivity.
Microbial systems are well studied, and genetic manipulations allow the optimization of microbial metabolisms for the production of terpenoid. Escherichia coli is well-known as a heterologous natural product biosynthesis organism. This bacterium has good capacity for directly manipulating of DNA in genetic engineering.
Methods: This review studied some preparation methods of second-generation Taxols. We have a glance on recent studies of E.coli’s manipulations in biochemical signal transduction pathways and constructed cDNA libraries in Taxol production process.
Results: Taxol is an isopernoid, there are alternative pathways in E.coli to produce it. In the mevalonate (MVA) pathway, acetyl coenzyme A (acetyl-CoA) converted to IPP (isopentenyl pyrophosphate) through six reactions. Another way is methylerythritol 4-phosphate (MEP) or terpene biosynthetic pathway. The upstream MEP or heterologous MVA pathways can produce the two common building blocks, isopentenyl pyrophosphate (IPP) and dimethyl-allyl pyrophosphate (DMAPP), which Taxol and other isoprenoid compounds are formed. IPP, metabolic pathway an upstream isoprenoid pathway, is native to E. coli and a heterologous downstream terpenoid pathway.The Taxol pathway starts from the E. coli isoprenoid precursor IPP and DMAPP to precursor geranylgeranyl diphosphate, taxadiene, taxadien-5α-ol followed by multiple rounds of stereospecific oxidations, acylations, benzoylations and epoxidation to form the late intermediate Baccatin III and then a side chain it will be added to formation Taxol. Baccatin III the intermediate of Taxol, isolated from plant sources, and converted to Taxol.
In first step glyceraldehyde-3 phospate (G3P) and pyruvate (PYR) are precursors of isoprenoid pathway, several enzyme involved in the biosynthetic pathways from G3P and PYR to Taxol. Furthermore there are many enzymes towards the produce taxol. All the enzyms could targeted for over-expression by an operon in E. coli.
cDNA of taxa-4(20),11(12)-dien-5alpha-ol-O-acetyl transferase, benzoyl-CoA: taxane 2alpha-O-benzoyltransferase, Overexpression and variation of copy number and promoter of 1-deoxy-D-xylulose-5-phosphate synthase (dxs), isopentenyl-diphosphate isomerase (idi), 4-diphosphocytidyl-2C-methyl-D-erythritol synthase (ispD), and 2C-Methyl-D-erythritol-2,4- cyclodiphosphate Synthase (ispF) and Overexpression of isopentenyl diphosphate isomerase, geranylgeranyl diphosphate synthase and taxadiene synthase in MEP pathway could be used for cDNA cloning Taxol production.
Conclusion: This study reviewed some Taxol biosynthesis way by E.coli and survey it’s the enzymatic pathways. There are new efficient routes to Taxol biosynthesis. It providing potential commercial production of microbial derived for use as chemicals and cancer chemotherapeutic drugs for treatment of cancer patinas. Producing of accurate taxol by microorganism such E.coli is economic and have less problem for useless toxic material production in comparison to another artificial ways.