Research progress on the source, production, and anti-cancer mechanisms of paclitaxel / 中国天然药物

Paclitaxel, a tetracyclic diterpenoid compounds, was firstly isolated from the bark of the Pacific yew trees. Currently, as a low toxicity, high efficiency, and broad-spectrum natural anti-cancer drug, paclitaxel has been widely used against ovarian cancer, breast cancer, uterine cancer, and other cancers. As the matter of fact, natural paclitaxel from Taxus species has been proved to be environmentally unsustainable and economically unfeasible. For this reason, researchers from all over the world are devoted to searching for new ways of obtaining paclitaxel. At present, other methods, including artificial cultivation of Taxus plants, microbial fermentation, chemical synthesis, tissue and cell culture have been sought and developed subsequently. Meanwhile, the biosynthesis of paclitaxel is also an extremely attractive method. Unlike other anti-cancer drugs, paclitaxel has its unique anti-cancer mechanisms. Here, the source, production, and anti-cancer mechanisms of paclitaxel were summarized and reviewed, which can provide theoretical basis and reference for further research on the production, anti-cancer mechanisms and utilization of paclitaxel.

Upregulation of miR-129-5p increases the sensitivity to Taxol through inhibiting HMGB1-mediated cell autophagy in breast cancer MCF-7 cells

Although Taxol has improved the survival of cancer patients as a first-line chemotherapeutic agent, an increasing number of patients develop resistance to Taxol after prolonged treatment. The potential mechanisms of cancer cell resistance to Taxol are not completely clear. It has been reported that microRNAs (miRNAs) are involved in regulating the sensitivity of cancer cells to various chemotherapeutic agents. In this study, we aimed to explore the role of miR-129-5p in regulating the sensitivity of breast cancer cells to Taxol. Cell apoptosis and autophagy, and the sensitivity of MCF-7 cells to Taxol were assessed with a series of in vitro assays. Our results showed that the inhibition of autophagy increased the Taxol-induced apoptosis and the sensitivity of MCF-7 cells to Taxol. Up-regulation of miR-129-5p also inhibited autophagy and induced apoptosis. Furthermore, miR-129-5p overexpression increased the sensitivity of MCF-7 cells to Taxol. High mobility group box 1 (HMGB1), a target gene of miR-129-5p and a regulator of autophagy, was negatively regulated by miR-129-5p. We found that interference of HMGB1 enhanced the chemosensitivity of Taxol by inhibiting autophagy and inducing apoptosis in MCF-7 cells. Taken together, our findings suggested that miR-129-5p increased the chemosensitivity of MCF-7 cells to Taxol through suppressing autophagy and enhancing apoptosis by inhibiting HMGB1. Using miR-129-5p/HMGB1/autophagy-based therapeutic strategies may be a potential treatment for overcoming Taxol resistance in breast cancer.

Study on Inhibitory Effects and Mechanism of Bruceanine D Combined with Taxol on the Proliferation of Human Pancreatic Cancer Capan- 2 Cells / 中国药房

OBJECTIVE： To investigate the inhibitory effect and potential mechanism of Brucein D （BD） combined with Taxol on the proliferation of human pancreatic cancer Capan-2 cells. METHODS： Using Capan-2 cells as object， the proliferations after treated with BD （5， 10， 15， 20 μmol/L）， Taxol （10， 20， 30， 40 nmol/L） and BD+Taxol （5 μmol/L+10 nmol/L， 10 μmol/L+20 nmol/L， 15 μmol/L+30 nmol/L， 20 μmol/L+40 nmol/L） for 48 h were determined by sulfonyl rhodamine B method. Survival rate of cells and combination index （CI） were calculated. The clone formation assay was performed to detect the formation of clonal colonies after treated with BD （20 μmol/L，hereinafter）， Taxol （40 nmol/L，hereinafter）、BD+Taxol （20 μmol/L+40 nmol/L，hereinafter） for 24 h. The rate of clone formation was calculated. DAPI method was used to observe the apoptosis of cells after treated with BD， Taxol and BD+Taxol for 24 h. Western blotting was used to detect the expression of apoptosis-related protein （Bcl-2， PARP， Caspase-3， Cleaved-caspase-3） after treated by BD， Taxol， BD+Taxol for 48 h and the expression of JNK and p-JNK after treated by BD， Taxol， BD+Taxol for 4， 6， 12 h. RESULTS： After treated with 10， 15 and 20 μmol/L BD， 20， 30 and 40 nmol/L Taxol or two-drug combination for 48 h， survival rates of cells were decreased significantly； the survival rate of drug combination group was significantly lower than the same dose of BD group and Taxol group （P＜0.05）. CI values of drug combination groups （BD 5 μmol/L+Taxol 10 nmol/L， BD 10 μmol/L+Taxol 20 nmol/L， BD 15 μmol/L+Taxol 30 nmol/L， BD 20 μmol/L+Taxol 40 nmol/L） were 0.63±0.04， 0.68±0.08， 0.89±0.12 and 0.84±0.05. After treated with 20 μmol/L BD， 40 nmol/L Taxol and two-drug combination， the formation of clonal colonies was decreased with different degrees of chromatin concentration and nuclear shrinkage； the rate of clone formation （24 h）， the expression of Bcl-2 （48 h）， PARP （48 h）， Caspase-3 （48 h） and JNK （4， 6 h， except for Taxol group） were decreased significantly， while the relative expression of Cleaved-caspase-3 （48 h） and p-JNK （4， 6， 12 h） were increased significantly. Those of BD+Taxol group were significantly better than those of BD group and Taxol group [except for JNK （4， 6， 12 h）， p-JNK （4 h）] （P＜0.05 or P＜0.01）. CONCLUSIONS： Both BD and Taxol can inhibit the proliferation and promote apoptosis of human pancreatic cancer Capan-2 cells， and the combination have a certain synergistic effect， which is better than any single drug. It may be associated with activating Caspase pathway and JNK phosphorylation.

Combinatorial mutation on the -glycosidase specific to 7--xylosyltaxanes and increasing the mutated enzyme production by engineering the recombinant yeast

Taxol is a "blockbuster" antitumor drug produced by species with extremely low amount, while its analogue 7--xylosyl-10-deacetyltaxol is generally much higher in the plants. Both the fungal enzymes LXYL-P1-1 and LXYL-P1-2 can convert 7--xylosyl-10-deacetyltaxol into 10-deacetyltaxol for Taxol semi-synthesis. Of them, LXYL-P1-2 is twice more active than LXYL-P1-1, but there are only 11 significantly different amino acids in terms of the polarity and acidic-basic properties between them. In this study, single and multiple site-directed mutations at the 11 sites from LXYL-P1-1 to LXYL-P1-2 were performed to define the amino acids with upward bias in activities and to acquire variants with improved catalytic properties. Among all the 17 mutants, E12 (A72T/V91S) was the most active and even displayed 2.8- and 3-fold higher than LXYL-P1-2 on -xylosidase and -glucosidase activities. The possible mechanism for such improvement was proposed by homology modeling and molecular docking between E12 and 7--xylosyl-10-deacetyltaxol. The recombinant yeast GS115-P1E12-7 was constructed by introducing variant , the molecular chaperone gene and the bacterial hemoglobin gene . This engineered yeast rendered 4 times higher biomass enzyme activity than GS115-3.5K-P1-2 that had been used for demo-scale fermentation. Thus, GS115-P1E12-7 becomes a promising candidate to replace GS115-3.5K-P1-2 for industrial purpose.

Sub-cellular localization and overexpressing analysis of hydroxylase gene TcCYP725A22 of Taxus chinensis / 生物工程学报

The discovery of hydroxylases in the anticancer drug taxol biosynthesis pathway is a hotspot and difficulty in current research. In this study, a new hydroxylase gene TcCYP725A22 (GenBank accession number: MF448646.1) was used to construct a sub-cellular localization vector pCAMIBA1303-TcCYP725A22-EGFP to get the transient expression in onion epidermal cells. Laser confocal microscopy revealed that the protein encoded by this gene was localized in the cell membrane. Furthermore, the recombinant plant expression plasmid pBI121-TcCYP725A22 was constructed. After transient transformation to the Taxus chinensis mediated by Agrobacterium tumefaciens LBA4404, qRT-PCR and LC-MS were utilized to analyze the effects of TcCYP725A22 overexpression on the synthesis of taxol. The results showed that, in the TcCYP725A22 overexpressed cell line, expression levels of most defined hydroxylase genes for taxol biosynthesis were increased, and the yield of taxanes were also increased. It was concluded that the hydroxylase gene TcCYP725A22 is likely involved in the biosynthetic pathway of taxol.

Screening of endophytic fungi stored in a culture collection for taxol production

Abstract In this work, four isolates of endophytic fungi (Alternaria alternata, Colletotrichum gloesporioides, Glomerella cingulata and Nigrospora sphaerica), deposited in the culture collection 'University Recife Mycologia' (URM) at the Universidade Federal de Pernambuco, were characterized for the genes ITS 1 and 4 (region 5.8 S) and evaluated for taxol production.

Molecular cloning and characterization of 1-deoxy-D-xylulose 5-phosphate synthase gene from Taxus chinensis / 中草药

Objective To obatin the key enzymes of 1-deoxy-D-xylulose 5-phosphate synthase (DXS) in taxol biosynthetic pathway from Taxus chinensis (TcDXS), and carry out the bioinformatics analysis, tissue profile, subcellular localization, and functional complementation assay. Methods RACE technologies were used to obtain the full length cDNA of TcDXS for the bioinformatics analysis. Semi-quantitative PCR was used to detect the gene expression levels in different parts of T. chinensis. The localization and function of TcDXS were carried out by subcellular localization and functional complementation assay. Results The full-length cDNA of TcDXS was 3 031 bp containing a coding sequence of 2 229 bp encoding a 742-amino-acid residues which was predicted to have a molecular weight of 79 400 and an isoelectric point of 7.99. The qRT-PCR results showed that the highest expression level of TcDXS was detected in petioles and followed by leaves and barks. However, the expression of TcDXS was very low in roots and stems. What’s more, functional complementation assay results showed that the E. coli, co-transformed with PAC-BETA and pTrcTcDXS, was changed to orange. Conclusion TcDXS was considered to play an essential role in the control of taxol biosynthesis and provided a target for the metabolic engineering of taxol production and plant molecular breeding in T. chinensis.

Screening of endophytic fungi stored in a culture collection for taxol production

Abstract In this work, four isolates of endophytic fungi (Alternaria alternata, Colletotrichum gloesporioides, Glomerella cingulata and Nigrospora sphaerica), deposited in the culture collection University Recife Mycologia (URM) at the Universidade Federal de Pernambuco, were characterized for the genes ITS 1 and 4 (region 5.8 S) and evaluated for taxol production.

Identification and characterization of a taxol-producing endophytic fungus from Taxus media / 生物工程学报

To enrich the resource pool of endophytic fungi from plants which produce taxol, a taxol-producing endophytic fungus TMS-26 was isolated from the stem of Taxus Media. The result of high performance liquid chromatography (HPLC) showed that TMS-26 extract exhibited similar chromatographic peaks and retention time (4.545 min) with authentic taxol. Then mass spectrometry (MS) analysis further confirmed that TMS-26 extracts contained the same mass peaks with authentic taxol ((M+Na)+=876). These indicated that the isolated endophytic fungus TMS-26 can produce taxol. According to the morphological characteristics, the molecular analysis of 18S rDNA and internal transcribed spacer nuclear rDNA gene sequence, the fungus was identified as Aspergillus fumigatus TMS-26.

Research and analysis of globally ecological suitability for Taxus plants / 药学学报

At present, taxol is an internationally acknowledged drug with a unique anticancer activity in the world and mainly come from Taxus plants, these plants have 12 species, all of which have been listed as endangered tree species and protected by the countries concerned. But available wild Taxus plants resources are rather rare, so it is very urgent to strengthen introduction and cultivation of Taxus plants to meet people's demand for taxol. According to the ecological similarity of growth of Taxus plants predict suitable areas in the whole world, which could put forward rational suggestions for introduction and planning production layout of plants. A geographic information system for global medicinal plants(GMPGIS)was developed by Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences independently, and using GMPGIS analyzed in detail the potential ecological suitable areas of Taxus plants. Ecological range of Taxus wallichiana var. chinensis, Taxus wallichiana var. mairei, Taxus baccata, Taxus brevifolia and Taxus wallichiana covered a wide field, and had larger suitable area in the northern and southern hemispheres; Taxus cuspidate mainly distributed in the northern hemisphere, and only scattered in the southern hemisphere; Taxus canadensis, Taxus floridana and Taxus cuspidata var. nana only distributed in the northern hemisphere, and the latter two prediction areas are relatively less areas; Taxus fauna, Taxus globosa and Taxus sumatrana grew up in relatively strict environment, belong to the niche species, scattered distribution and the distribution of the areas are rare. This research would exert an important promoting effect on the cultivation of Taxus plants and the escalation of abundance to guarantee the sufficient supply of raw materials for taxol production. Finally, this paper summarized the research on the ecological quality and resource conservation of Taxus plants, to provide the reference for scientific introduction and cultivation of Taxus plants.

Effect of senescence-associated secretory phenotype-conditioned medium on proliferation of human gastric cancer cell lines BGC823 / 第二军医大学学报

Objective To investigate the effect of senescence-associated secretory phenotype-conditioned medium (SASP-CM) on the proliferation of human gastric cancer cell lines BGC823. Methods BGC823 cells were divided into three groups: SASP-CM group, tumor cells control-conditioned medium (CTR-CM) group, and normal-conditioned medium (NOR-CM) group. BGC823 cells in theSASP-CM group were treated with paclitaxel (PTX) to establish senescent cell model and to prepare SASP-CM. The establishment of senescent cell model was confirmed by senescence- associated (Fgalactosidase staining. The concentrations of major SASP factors in SASP-CM were detected by enzyme linked lmmunosorbent assay, the proliferationability ofBGC823 cells was detected by CCK-8 assay and cell clone formation assay, and the cell cycle and apoptosis were detected by flow cytometry. Results After treating BGC823 cells with 35 nmol/L PTX for 72 h, a steady senescence modll was established, which had the highest percentage of senescence cells ([66.95±3.54]%). The concentrations of lnterleukin (IL)-6, IL-8, chemokine (C-X-Cmotif) ligand 1 (CXCL1), chemokine (C-C motif) ligand 2 (CCL2), and lnterferon γ (INF-γ) in the SASP-CM were significantly higher than those ln the CTR-CM (all P<0.01). The relative clone formation rate of BGC823 cells in the SASP-CM group was significantly higher than those ln the CTR-CM group (P<0.01) and NOR-CM group (P<0. 05). The proliferation activity of BGC823 cells in the SASP-CM group was significantly higher than that in the CTR-CM and NOR-CM groups after incubation for 48, 72 and 96 h (all P<0.05). The percentage of S phase cells in the SASP-CM group was significantly higher than that in the CTR-CM and NOR-CM groups (both P<0.01), and there was no significant difference in cell apoptosis rate between groups. Conclusion SASP-CM can promote the proliferation of human gastric cancer cell lines BGC823.

Comparative analysis on contents of 10-deacetyl-bacratin III, cephalomannine, taxol of Taxus madia from different habitats and growth years / 中草药

Objective To analysis and compare the content differences of three effective components of taxanes of Taxus madia Rehd. from five different habitats and growth years by High Performance Liquid Chromatography (HPLC). Methods The mixed liquor of CH3OH and CHCl3 was used for the ultrasonic extraction of 10-deacetyl-bacratin III (10-DAB III), cephalomannine and taxol before being dissolved by CH3OH to obtain sample solution. By HPLC, the contents of three effective components were performed and compared. Results There were extremely significantly differences (P SM3 > SM2, ZL3 > HK4 > ZL4, ZL3 > SM2 > HK4, HK4 > ZL3 > ZL6, respectively. Except for the contents of 10-DAB III and cephalomannine, there were significant positive correlations among the contents of other components (P < 0.01). The contents of taxol would rise or decline when the total contents of three kinds of taxanes rised or declined among different habitats and growth years. The clustering analysis results showed that the contents of taxol have certain peculiarity. In Fuzhou of Fujian, while the total contents of three kinds of taxanes were different from others in Kaifen of Henan. Conclusion Habitants and growth years have a significant impact on the contents change of three effective components of taxanes from Taxus madia Rehd.. Therefore, regulation and control of biosynthetic pathway by choosing habitat conditions and harvest years should be considered, in order to obtain more crude drug of taxol in T. madia.

Effects of Taxol on proliferation, apoptosis, and mRNA expression of α2,6-sialic acid and ST6Gal in cervical carcinoma cell line U14 / 中国病理生理杂志

AIM:To study the effect of Taxol on the proliferation, apoptosis, and mRNA expressions of α2,6-sialic acid (SA) and α2,6-sialyltransferase (ST6Gal) in mouse cervical cancer cell line U14.METHODS:After the U14 cells were treated with Taxol, the IC50 value of Taxol to U14 cells was detected by MTT assay.The expression of α2,6-SA and apoptosis-related factors (Bcl-2, Bax, caspase 8 and caspase 3), the apoptosis rate and cell cycle were determined by flow cytometry.The mRNA expression of ST6Gal1 and ST6Gal2 was detected by qPCR.RESULTS:As compared with control group, Taxol induced obvious U14 cell growth inhibition, reduced α2,6-SA expression, up-regulated Bax, down-regulated Bcl-2, decreased the ratio of Bcl-2/Bax, enhanced caspase 8 and caspase 3 activity, increased the apoptotic rate and cell proportions of Sub-G1 and S phases, and induced G2/M phase arrest.Taxol also down-regulated the mRNA expression of ST6Gal1, and slightly up-regulated the mRNA expression of ST6Gal2.CONCLUSION:α2,6-SA and ST6Gal are involved in the multiple effects of Taxol on modulation of the cell cycle and apoptosis in U14 cells.

Relationship between SPAG5 Low Expression and Poor Prognosis of Ovarian Early Stage High Grade Serous Carcinoma Patients / 中山大学学报(医学科学版)

[Objective] To investigate the role SPAG5 play in ovarian adenocarcinoma cell mitosis,Taxol sensitivity and ovarian high grade serous carcinoma patients' prognosis.[Methods] Transient knockdown of SPAG5 in SKOV3 cell were performed,and MTT assay and cell cycle flow cytometry assay were carried out.IHC staining of SPAG5 protein in 110 high grade serous carcinoma patients' tumor tissues were performed,and the expression were analyzed with clinical data and prognosis.Finally,SPAG5 were knocked down in OVCAR3 A2780 and SKOV3 cells followed by 0.5μM Taxol treatment,MTT assay were performed to detect cell viability.[Results] SPAG5 knockdown inhibited cell mitosis of ovarian adenocarcinoma cell SKOV3 by G2/M arrest.High grade serous carcinoma patients after neoadjuvant chemotherapy gained the expression of SPAG5.Patients without neoadjuvant chemotherapy with low SPAG5 expression have poor progress free survival,especially in early stage patients.Patients with low SPAG5 expression also have poorer overall survival,but the difference was not statistically significant.Furthermore,SPAG5 knockdown in OVCAR3 A2780 and SKOV3 cells reduced Taxol sensitivity.[Conclusion] SPAG5 regulated cell mitosis and promoted cell proliferation in ovarian adenocarcinoma cell lines.Expression of SPAG5 in patients' tumor tissues predicted patients' prognosis and Taxol sensitivity.As the results,individualized treatment of high grade serous carcinoma patients is necessary.

Clinical Observation of Taxol Combined with Cisplatin Neoadjuvant Chemotherapy in the Treatment of Esophageal Cancer / 中国药房

OBJECTIVE:To observe the clinical efficacy of taxol combined with cisplatin neoadjuvant chemotherapy in the treatment of esophageal cancer and effects on serum tumor markers in patients with esophageal cancer. METHODS:100 patients with esophageal cancer were randomly divided into control group(50 cases) and observation group(50 cases). Observation group was given taxol+Cisplatin injection(TP)neoadjuvant chemotherapy,given 175 mg/m2 taxol by intravenous infusion,d1-5. And ev-ery 5 d was a treatment course,the regimen was adjusted based on patients’efficacy;control group was given conventional sur-gery and TP after surgery,the same usage and dosage as observation group,it lasted for 4 courses. Clinical efficacy,high mobility protein B1(HMGB1),carcinoembryonic antigen (CEA) and squamous cell carcinoma antigen (SCC-Ag) level in 2 groups before and after treatment were observed,objective response rate,disease control rate,the incidence of toxicity and severe toxicity,inci-dence of postoperative complications and survival rate of postoperative 1,3 and 5 years were recorded. RESULTS:After treatment, objective response rate in observation group was significantly higher than control group,HMGB1,CEA and SCC-Ag levels were significantly lower than before and control group,HMGB1 and CEA levels in control group were significantly lower than before, the differences were statistically significant(P0.05). CONCLUSIONS:Taxol combined with cisplatin neoadjuvant chemotherapy can significantly improve the efficacy of patients with esophageal cancer and reduce the levels of cancer-related indicators,with good safety.

Expression of stathmin and its influence on taxol sensitivity in esophageal squamous cell carcinoma / 医学研究生学报

Objective Stathmin, a microtubule-destabilizing protein , has high expression in esophageal squamous cell carci-noma(ESCC), while taxol is a common chemotherapy microtubule-targeted drug for esophageal cancer .This study aimed to investigate the impact of stathmin expression and its influence on taxol sensitivity in ESCC . Methods We established 2 cell models with ST-MN1 gene overexpression in KYSE 510 and KYSE 170 cell lines, including KYSE 510-Stathmin, KYSE 170-Stathmin, KYSE 510-Control and KYSE 170-Control.MTT assay and colony formation were applied to compare the taxol sensitivity between experimental group and control group .Flow cytometry was used to measure the apoptosis of KYSE 510-Stathmin and KYSE 510-Control after taxol treatment.Western blot was used to test the changes of related factors to apoptosis and autophagy . Results ①Stathmin protein ex-pressions in KYSE 510-Stathmin and KYSE 170-Stathmin cells were higher than those of control cells (P<0.01).② The percentages of inhibition were significantly decreased in KYSE 510-Stathmin and KYSE 170-Stathmin cells 24 h after 50, 100,250 nmol/L taxol treat-ment compared with KYSE 510-Stathmin cells(P <0.01).③The percentages of inhibition were significantly reduced in KYSE 510-Stathmin and KYSE 170-Stathmin cells after 250 nM taxol treatment for 24, 48, 60 h (P<0.01).④After taxol treatment,the number of colony formation in KYSE 510-Stathmin cells was higher com-pared with KYSE 510-Control cells (P<0.01).⑤The percentage of cell apoptosis in KYSE 510-Stathmin was significantly lower than that of KYSE 510-Control cells by flow cytometry (11.90%±0.78%vs 29.63%±3.26%, P<0.05).Western blot showed the ap-optosis of associated proteins such as the activation of Caspase 8 and Caspas9. Conclusion The result indicates that overexpression of stathmin inhibits taxol sensitivity in ESCC cell lines .

Apoptosis mechanism of taxol combined with resveratrol on human laryngeal carcinoma Hep-2 cells / 中国中药杂志

Laryngeal cancer is one of the most common malignant tumors in the respiratory tumors, and its incidence ranks second highest in the respiratory tumors. Resveratrol (Res) is a kind of polyphenols, which can inhibit nucleotides can inhibit the growth of liver cancer cells, gastric cancer cells, pancreatic cells and other tumor cells by inhibiting ribonucleotide reductase in the cells. Taxol (Tax) is a kind of secondary metabolites of Taxus chinensis, which has anti-tumor activity for breast cancer, cervical cancer, ovarian cancer and other tumors by inhibiting cellular microtubule depolymerization. But at present the effects of resveratrol combined with taxol on human laryngeal carcinoma cell strain Hep-2 and their underlying molecular mechanisms are rarely reported. After human laryngeal cancer cell Hep-2 cells were processed with resveratrol (Res) and taxol (Tax), CCK-8 assay was used to evaluate the effect of these two herbs on the proliferation of cancer cells; AO/PI staining and JC-1 were used to detect Hep-1 cells apoptosis; the expression of Bax, Bcl-2, PARP, TRIB3, and XIAP genes was detected by real time quantitative PCR; the activity of caspase-3 and caspase-8 was determined with quantitative fluorescence method. The experimental results showed that compared with Tax, Res medication alone, joint group significantly enhanced inhibition of Hep-2 cells activity, decreased the dosage of Tax, increased the expression of Bax and PARP, TRIB3, reduced the expression of the Bcl-2 and XIAP, and promoted the activity of caspase-3 and caspase-8. The test results showed that compared with the single medication, combined group could significantly increase the inhibitory effect on Hep-2 cells, significantly reduce Tax dosage, increase expressions of Bax, PARP, TRIB3, reduce expressions of Bcl-2, XIAP, and promote activity of caspase-3, caspase-8. This indicated apoptosis of human laryngeal carcinoma cell strain Hep-2 may be induced with Res, Tax, and the combination of these two herbs by mitochondria pathway. It provides valuable clue for further research on combination of Res and Tax for the treatment of laryngeal cancer, and expanding the combined application of Res and Tax.

Structure activity relationship of annonaceous acetogenins against multidrug resistant human lung cancer cell line A549/Taxol in vitro / 中国中药杂志

10 kinds of annonaceous acetogenins were selected for antitumor activity testing against human lung cancer cell line A549/Taxol and the structure activity relationship was analyzed.MTT assay was used to detect the inhibitory activities of 10 kinds of annonaceous acetogenins and positive drugs against A549/Taxol cells, respectively uvariamicin-Ⅲ(1), uvariamicin-Ⅱ(2), annosquacin D(3), desacetyluvaricin(4), annosquatin A(5), squamostatin D(6), bullatacin(7), squamocin(8), motrilin(9), annosquatin B(10), verapamil and cisplatin. Annonaceous acetogenins showed significant inhibitory activities against A549/Taxol cells, and were more potent than the positive drug verapamil and cisplatin.The more carbon atoms between the tetrahydrofuran ring and the lactone ring of annonaceous acetogenins exhibited more potency.Besides,ACGs with two substituted hydroxyl showed more potency than the compounds with three substituted hydroxyl in the bis-adjacent-THF ACGs. Furthermore, ACGs with three substituted hydroxyl showed more potency than the compounds with four substituted hydroxyl among the no bis-adjacent-THF ACGs.

Advances and prospects of taxol biosynthesis by endophytic fungi / 生物工程学报

Taxol is one of the most important chemotherapeutic drugs against cancer. Taxol has been mainly extracted from the bark of yews for a long time. However, methods for the extraction of taxol from the bark of Taxus species were inefficient and environmentally costly. As a result of the high ecological toll exacted on trees with the potential for Pacific yew extinction, investigators began to look for other methods of taxol production. Recently, increasing efforts have been made to develop alternative means of taxol production, such as using complete chemical synthesis, semi-synthesis, Taxus spp. plant cell culture and microbe fermentation. Using microbe fermentation in the production of taxol would be a very prospective method for obtaining a large amount of taxol. Therefore, it is necessary to understand the molecular basis and genetic regulation mechanisms of taxol biosynthesis by endophytic fungi, which may be helpful to construct the genetic engineering strain with high taxol output. In this paper, the taxol biosynthesis pathway from Taxus cells and the advantages of taxol biosynthesis by endophytic fungi were discussed. The study on the isolation and biodiversity of taxol-producing endophytic fungi and the taxol biosynthesis related genes are also discussed.

Systematic Analysis of the Anticancer Agent Taxol-Producing Capacity in Colletotrichum Species and Use of the Species for Taxol Production

Paclitaxel (taxol) has long been used as a potent anticancer agent for the treatment of many cancers. Ever since the fungal species Taxomyces andreanae was first shown to produce taxol in 1993, many endophytic fungal species have been recognized as taxol accumulators. In this study, we analyzed the taxol-producing capacity of different Colletotrichum spp. to determine the distribution of a taxol biosynthetic gene within this genus. Distribution of the taxadiene synthase (TS) gene, which cyclizes geranylgeranyl diphosphate to produce taxadiene, was analyzed in 12 Colletotrichum spp., of which 8 were found to contain the unique skeletal core structure of paclitaxel. However, distribution of the gene was not limited to closely related species. The production of taxol by Colletotrichum dematium, which causes pepper anthracnose, depended on the method in which the fungus was stored, with the highest production being in samples stored under mineral oil. Based on its distribution among Colletotrichum spp., the TS gene was either integrated into or deleted from the bacterial genome in a species-specific manner. In addition to their taxol-producing capacity, the simple genome structure and easy gene manipulation of these endophytic fungal species make them valuable resources for identifying genes in the taxol biosynthetic pathway.