Concentrations Of Taxol Research Articles

M 6 A reader IGF2BP1 reduces the sensitivity of nasopharyngeal carcinoma cells to Taxol by upregulation of AKT2.

Taxol is widely used in the treatment of nasopharyngeal carcinoma (NPC); nevertheless, the acquired resistance of NPC to Taxol remains one of the major obstacles in clinical treatment. In this study, we aimed to investigate the role and mechanism of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in Taxol resistance of NPC. Taxol-resistant NPC cell lines were established by exposing to gradually increased concentration of Taxol. Relative mRNA and protein levels were tested using qRT-PCR and western blot, respectively. NPC cell viability and apoptosis were assessed by cell counting kit-8 and flow cytometry analysis, respectively. Cell migration and invasion capacities were measured using transwell assay. Interaction between IGF2BP1 and AKT2 was examined by RNA immunoprecipitation assay. The N6-methyladenosine level of AKT2 was tested using methylated RNA immunoprecipitation-qPCR. IGF2BP1 expression was enhanced in Taxol-resistant NPC cell lines. Knockdown of IGF2BP1 strikingly enhanced the sensitivity of NPC cells to Taxol and repressed the migration and invasion of NPC cells. Mechanistically, IGF2BP1 elevated the expression of AKT2 by increasing its mRNA stability. Furthermore, overexpression of AKT2 reversed the inhibitory roles of IGF2BP1 silence on Taxol resistance and metastasis. Our results indicated that IGF2BP1 knockdown enhanced the sensitivity of NPC cells to Taxol by decreasing the expression of AKT2, implying that IGF2BP1 might be promising candidate target for NPC treatment.

Microtubule cytoskeleton inhibition induced by taxol and vinorelbine affects encystation, proliferation, morphology, and gene expression of Cryptocaryon irritans protomont

Cryptocaryon irritans protomont is important for encystation and division to continue the reinfection events. Microtubules play a determinant role in multiple cell processes such as: motility, intracellular transport, division, encystation and excystation. To evaluate the significance of microtubule cytoskeleton in Cryptocaryon irritans encystation and cyst proliferation, taxol (a tubulin polymerizing agent) and vinorelbine (a tubulin depolymerizing agent) were used. Using a structure-activity approach, their effects on the regulation of encystment, cyst proliferation, division, morphology, and encystment-related gene expression were assessed. Following collection, protomonts were exposed to serial concentrations of taxol (25, 50, 100, 250, and 500 μM) and vinorelbine (100, 250, 500, 750, and 1000 μM) for 1, 2, 3, and 12 h. Survival, encystation rate, excystation number of theronts, and theront body size decreased with varying degrees of time and concentration. Furthermore, the effects of anti-tubulins on the micro- and ultrastructure of protomonts were examined using the most feasible concentrations of 250 μM taxol and 500 μM vinorelbine. Microstructure observations for one cell cycle revealed delayed/incomplete encystation, change in cell symmetry, and delayed excystation process. Ultrastructure observations showed aggregation of microtubule bundles and disruption of microtubule assembly in the cytoplasm and around the cell wall of taxol- and vinorelbine-treated protomonts respectively. Inhibited microtubules altered ultrastructure resulting in fragile/fragmentary cyst wall formation. mRNA expression of α- and β-tubulin in the taxol-treated cells was significantly up-regulated when compared with the control (P˂0.05). In contrast, vinorelbine treatment markedly down-regulated mRNA expression levels of α- and β-tubulin at one and four hours (P˂0.05). mRNA level of EF-1α was enhanced in taxol-treated protomonts, but reduced in vinorelbine-treated cells when compared with the control (P˂0.05). While mRNA level of actin-cytoplasmic1 remained almost stable after treatment with both anti-tubulin drugs, mRNA expressions of other targeted genes- Rab-7, 40s ribosomal protein, and cathepsin were insignificantly down-regulated in both treatments when compared with control (P > 0.05). In general, target-specific taxol and vinorelbine were found to disturb the rate of encystation, cyst growth, and morphology. In addition, these drugs caused irregular mRNA expression of α- and β-tubulins. This study elucidates the constructive role of tubulins in protomont encystation and cyst proliferation.

Production of the anticancer drug taxol by the endophytic fungus Epicoccum nigrum TXB502: enhanced production by gamma irradiation mutagenesis and immobilization technique.

Taxol, a phyto-extracted diterpenoid, is the most commercially needed drug in cancer chemotherapy. In spite of the microbial production of taxol being successful and prospective, the reported yields are still not sufficient for large-scale production. Thus, the discovery of new taxol-producing microbial strains and production enhancement methodologies such as process optimization, strain improvement, and immobilization technique are the main objectives. In this paper, a taxol-producing start strain Epicoccum nigrum TXB502 (initial yield 61.35 μg L-1) was isolated from Taxus baccata and identified by morphological and molecular tools. The optimum cultivation and nutritional conditions were assessed by testing one parameter at a time approach that resulted in 88.59% significant production increase. In addition, a stable mutant with improved productivity (40.07% yield increase in comparison with the parent strain) was successfully developed after gamma irradiation mutagenesis of the start strain. The taxol titer was further improved via testing different immobilization carriers for both spores and mycelia of this mutant. Over taxol production was achieved using alginate-immobilized mycelia with the feasibility of conducting six successive production cycles in a semi-continuous form. The final total concentration reached 8187.77 μg taxol 6 L-1 which represents approximately 22-fold increase, as compared to the initial titer of the start strain. These findings can pave the way for the prospective industrial manufacturing of taxol, as the achieved taxol production in this study is the highest reported by academic laboratories for microbial cultures. KEY POINTS: • Discovery of a new taxol-producing endophytic fungus E. nigrum TXB502 strain. • Taxol yield was successfully improved via bioprocess optimization and strain mutagenesis. • Alginate-immobilized mycelia were efficient for a semi-continuous production of taxol. • The final total concentration of taxol showed approximately 22-fold increase as compared to the initial titer.

Sites of biosynthesis and storage of Taxol in Taxus media (Rehder) plants: Mechanism of accumulation

Taxol is a cytotoxic agent against various types of cancers. The cytotoxic activities of Taxol can be extended to its synthesizing plant. Here, Taxol is shown to have special synthesis, storage and transport mechanisms that avoid the toxic effects on its source plant. The sites of Taxol biosynthesis, transport and storage were revealed by quantification of plant Taxol, its intermediate baccatin III, the polyphenol side chain precursor , gene expression analysis of the major Taxol biosynthetic genes and in situ immuno-labeling. Although the biosynthesis of Taxol was limited by the expression of its biosynthetic genes and the presence of baccatin III, its presence did not correlate to baccatin III accumulation, nor to the expression of biosynthetic genes. However, Taxol presence positively correlated to polyphenol accumulation (late stage in Taxol assembly) and the resin-like hydrophobic bodies (HB, storage organelles). These results indicate that the presence of Taxol requires two complementary steps, biosynthesis followed by storage. Each step is limited by the availability of different precursors, which differ in their localization within the plant. Thus, the sites of biosynthesis, transport and storage of Taxol are different. Taxus media (Rehder) plant wood showed high concentrations of baccatin III and the expression of biosynthetic genes. However, the concentrations of Taxol, polyphenol and HB were very high in the plant outer layers including phloem and dead bark (rhytidome). Furthermore, in situ immuno-labeling showed that taxadiene synthase (the rate-limiting enzyme in Taxol biosynthesis) was mainly found in the wood, while Taxol primarily localized to the outer tissues. Conclusively, wood can be considered as the site of Taxol biosynthesis. Our data also propose that Taxol then accumulates into HB in order to permit its transport within the living plant tissues without causing toxic effects. This is followed by Taxol storage in the outer tissues including phloem and dead bark.

Functional activity of mitochondria associated with cytoskeleton stability in the HEK293

Mitochondria are dynamic cellular organelles that provide the biological energy to the cell. The dynamic property of the mitochondria is associated with the cytoskeleton network in the cell. However, relationship is no clear identified between cytoskeleton instability and the functional activity of mitochondria in cell. This study is designed to assess the dynamic properties of the mitochondria, and specifically to observe whether they are associated with the cytoskeleton stability for the mitochondria’s functional activityWe prepared the cytoskeleton stability regulation model with the HEK293 cell line by vinorelbine which microtubule distributor and the cytoskeleton stabilizer as a taxol. We determined the optimal concentration of vinorelbine and taxol though cytotoxicity assay with the HEK293 cell line. Then, we analyzed the functional activity of the mitochondria depending on the microtubule instability. First, we undertook an observation of cell morphology under distributor or stabilizer. We analyzed the metabolic activity of the cell with the CCK and ATP productive assay. And we performed confocal live imaging for observation of mitochondria morphology in the cytoskeleton instable cells. We performed the reverse transcription polymer chain reaction for analysis of the mRNA expression in the cytoskeleton’s instable cells with Tau protein, Glut1 and GAPDH as the normalization marker.The vinorelbine treated cell shows dramatically changes with cell morphology compared with control. And the vinorelbine treated cell significantly increases the fission ratios of the mitochondria compared with the original form based on the confocal images. Microtubule instable cells significantly decreased the ATP’s productive ratios and the functional activity of the mitochondria. However, the cytoskeleton stabilizer as a taxol(0.01uM) combined with vinorelbine treated cells, shows recovery effect to cell morphology recovery effect like the control cells that were only treated with vinorebine. And taxol that was combined with vinorelbine treated cells significantly increased bioenergy product ratios and its functional activity compared with the vinorelbine.In conclusion, the dynamic mitochondrial motility might influence the microtubule stability in cells. Because, vinorelbine‐treated cells displayed destabilized microtubules, loss of motility and fission formation of mitochondria. And loss motility of the mitochondria shows poor ATP productive ratios, resulting in a phenotype like that observed in the cells. This data suggests that functional activity of the mitochondria is associated with the microtubule stability in the cells. And microtubule stabilizer has a possibility to recovery functional activity in the microtubule instable cell like aging process. This finding can be applying to understand the mechanism of aging.Support or Funding InformationThis research was supported by the University Innovation Support Project (UISP) through the National Research Foundation (NRF) funded by MEST(Project No. 20190104)CCK analysis(A) and cell morphology(B) of NaB and Taxol treated cellsFigure 1ATP productive ratios(A) and fission form of mitochondria(B) of cellsFigure 2

Semi-continuous production of the anticancer drug taxol by Aspergillus fumigatus and Alternaria tenuissima immobilized in calcium alginate beads.

Taxol is the most profitable drug ever developed in cancer chemotherapy; however, the market demand for the drug greatly exceeds the supply that can be sustained from its natural sources. In this study, Aspergillus fumigatus TXD105-GM6 and Alternaria tenuissima TER995-GM3 were immobilized in calcium alginate beads and used for the production of taxol in shake flask cultures. In an effort to increase the taxol magnitude, immobilization conditions were optimized by response surface methodology program (RSM). The optimum levels of alginate concentration, calcium chloride concentration, and mycelium fresh weight were 5%, 4%, and 15% (w/v), respectively. Under these conditions, taxol production by the respective fungal strains was intensified to 901.94μg L-1 and 529.01μgL-1. Moreover, the immobilized mycelia of both strains were successfully used in the repeated production of taxol for six different fermentation cycles. The total taxol concentration obtained in all cycles reached 4540.14μgL-1 by TXD105-GM6 and 2450.27μgL-1 by TER995-GM3 strain, which represents 7.85- and 6.31-fold increase, as compared to their initial titers. This is the first report on the production of taxol in semi-continuous fermentation. To our knowledge, the taxol productivity achieved in this study is the highest reported by academic laboratories for microbial cultures which indicates the future possibility to reduce the cost of taxol production.

Taxol Improves Pre-Implantation Development Potential of Mouse Embryos

Aim: The objective of the present study was to investigate the development of mouse embryos and the chromosomal status after the pre-implantation treatment with paclitaxel (Taxol) based on the reports that indicate Taxol improves the developmental potential of vitrified human and mouse oocytes. Methods: Outbred female mice were superovulated and in vitro fertilization (IVF) was carried out using sperms from the same strain. Two-cell stage mouse embryos were cultured in the presence of Taxol for 24 h. After the determination of a non-toxic dose of Taxol, embryo development in control and Taxol-treated groups was compared during 3.5 days post-IVF. The aneuploidy rate of embryos was assessed by fluorescence in situ hybridization for chromosomes 2 and 11. Results: Development to morula and blastocyst stages was considerably enhanced following the addition of Taxol 0.01 µM compared to a similar situation in controls (p < 0.0001). Moreover, the degeneration rate was decreased following treatment with this concentration of Taxol (p < 0.01). The rate of aneuploidy in embryos and individual blastomeres did not vary between groups (p = 0.518 and 0.810 respectively). Conclusion: Pre-implantation treatment with Taxol 0.01 µM had a positive effect on the development to morula/blastocyst stages and decreased the degeneration rate without affecting the aneuploidy rate of chromosomes 2 and 11.

Taxol-Loaded MSC-Derived Exosomes Provide a Therapeutic Vehicle to Target Metastatic Breast Cancer and Other Carcinoma Cells.

MSC-derived exosomes display, among others, an efficient biocompatibility and a reduced intrinsic immunogenicity, representing a valuable vehicle for drug delivery in a tumor-therapeutic approach. Following treatment of several human mesenchymal stroma/stem-like cell (MSC) populations with sub-lethal concentrations of taxol for 24 h, exosomes were isolated and applied to different human cancer populations including A549 lung cancer, SK-OV-3 ovarian cancer, and MDA-hyb1 breast cancer cells. While MSC control exosomes revealed little if any growth inhibition on the tumor cells, exposure to taxol-loaded MSC-derived exosomes was associated with 80–90% cytotoxicity. A similar application of taxol-loaded exosomes from HuVEC displayed much fewer effects. Quantification by LC-MS/MS analysis demonstrated a 7.6-fold reduced taxol concentration in MSC exosomes when compared to equivalent cytotoxic in vitro effects achieved with taxol substances, indicating a specific and more efficient tumor-targeting property. Consequently, MSC-derived taxol exosomes were tested in vivo. Highly metastatic MDA-hyb1 breast tumors were induced in NODscid mice, and systemic intravenous application of MSC-derived taxol exosomes revealed a more than 60% reduction of subcutaneous primary tumors. Moreover, the amount of distant organ metastases observed at least in lung, liver, spleen, and kidney was reduced by 50% with MSC taxol exosomes, similar to the effects observed with taxol, although the concentration of taxol in exosomes was about 1000-fold reduced. Together, these findings in different cancer cell populations and in vivo provide promising future perspectives for drug-loaded MSC-derived exosomes in efficiently targeting primary tumors and metastases by reducing side effects.

A Method for Astral Microtubule Tracking in Fluorescence Images of Cells Doped with Taxol and Nocodazole

In this paper, we describe an algorithm that performs automatic detection and tracking of astral microtubules in fluorescence confocal images. This sub-population of microtubules only exists during and immediately before mitosis and aids in the spindle orientation by connecting it to the cell cortex. Anomalies in their dynamic behaviour play a causal role in many diseases, such as development disorders and cancer. The main novelty of the proposed algorithm lies in the fact it provides a fully automated estimation of parameters related to microtubule dynamic instability (growth velocity, track length and track lifetime), and helps in understanding the effects of intermediate drug concentrations. Its performance has been objectively assessed using publicly available synthetic data and largely employed metrics. Moreover, we present experiments addressing cell cultures doped with different concentrations of taxol and nocodazole. Such drugs are known to suppress the microtubule dynamic instability, but their effects at intermediate concentrations are not completely assessed. The algorithm has been compared with other state-of-the-art approaches, tested on consistent real datasets. The results are encouraging in terms of performance, robustness and simplicity of use, and the algorithm is now routinely employed in our Department of Molecular Biotechnology.

Establishment of a drug-resistant human cervical cancer cell line and research on its drug-resistance.

To investigate the differences and international connections between the human cervical cancer cell line (HeLa cells) and the Taxol-resistant HeLa cell line (HeLa/Taxol). As parental cells, HeLa cells were cultured in stepwise escalating concentration of Taxol from 0.01 μg/ml (11.7 × 10-9 mol/L) to 0.5 μg/ml (585 × 10-9 mol/L). The drug resistance of HeLa/Taxol cells was detected by methyl-thiazolyl-tetrazolium assay. Real time-polymerase chain reaction (RT-PCR) was conducted to detect the messenger RNA levels of drug resistance genes and apoptosis-related genes. The proteins levels were detected through immunofluorescence and Western blot. Compared with parental HeLa cells, HeLa/Taxol with Taxol resistance had the following biological characteristics: first, they had a lower growth velocity; second, the expression of P-glycoprotein and glutathione S-transferases was significantly increased; Third, the expression of antiapoptotic protein Bcl-2 and apoptosis inhibitor protein survivin was prominently increased. The drug-resistance in HeLa/Taxol is mainly associated with the high expression of multidrug resistance genes, antiapoptotic protein Bcl-2, and apoptosis inhibitor protein survivin as an important reason for the failure of chemotherapy of tumor tissue.

Correction: Ruxolitinib sensitizes ovarian cancer to reduced dose Taxol, limits tumor growth and improves survival in immune competent mice.

[This corrects the article DOI: 10.18632/oncotarget.21541.].

Alpha1,2-fucosyl transferase gene, the key enzyme of Lewis y synthesis, promotes Taxol resistance of ovarian carcinoma through apoptosis-related proteins.

We aimed to investigate the role of FUT1 gene in Taxol resistance and to explore its mechanism in epithelial ovarian cancer. Three ovarian cancer cell lines, ES-2, SK-OV-3 and OVCAR-3 were selected from epithelial ovarian cancer in this experiment. Western blot was used to validate the protein expression level of FUT1 and the apoptosis proteins. The expression level of the corresponding carrier was validated by RT-PCR. Transfection and isolation of stable transfectants were carried out to establish the cell line models. The different concentrations of Taxol on the inhibition of cell growth rate was measured by MTT, in which Taxol resistance profiling in ovarian cancer cells was determined by IC50 data. Flow cytometry was conducted to compare cell apoptosis ability. Caspase-3 activity and the apoptosis proteins were measured by colorimetry and western blot, respectively, to further compare the cell apoptosis ability in different groups. To demonstrate the inhibition of miR-FUT1 combined with Taxol therapy against ovarian cancer, xenograft assay was carried out for the in vivo effect. The western blot results indicate that FUT1 is expressed in all of the ovarian cancer cells with different expression level: ES-2 > SK-OV-3 > OVCAR-3. Besides, FUT1 siRNA was used in the maximum expression of FUT1 cell line ES-2, or over-expression plasmid was used in the minimum expression of FUT1 cell line OVCAR-3, to establish stable expression cell lines. After the treatment with Taxol, the inhibition rate of Taxol was obviously decreased with the established cell model above, and the IC50 level was significantly increased in the FUT1 over-expression + Taxol group (p Keywords: FUT1, Lewis y, Taxol resistance, ovarian cancer, apoptosis.

Association between Twist and multidrug resistance gene-associated proteins in Taxol®-resistant MCF-7 cells and a 293 cell model of Twist overexpression.

Multidrug resistance (MDR) severely limits the effectiveness of chemotherapy. Previous studies have identified Twist as a key factor of acquired MDR in breast, gastric and prostate cancer. However, the underlying mechanisms of action of Twist in MDR remain unclear. In the present study, the expression levels of MDR-associated proteins, including lung resistance-related protein (LRP), topoisomerase IIα (TOPO IIα), MDR-associated protein (MRP) and P-glycoprotein (P-gp), and the expression of Twist in cancerous tissues and pericancerous tissues of human breast cancer, were examined. In order to simulate Taxol® resistance in cells, a Taxol®-resistant human mammary adenocarcinoma cell subline (MCF-7/Taxol®) was established by repeatedly exposing MCF-7 cells to high concentrations of Taxol® (up to 15 µg/ml). Twist was also overexpressed in 293 cells by transfecting this cell line with pcDNA5/FRT/TO vector containing full-length hTwist cDNA to explore the dynamic association between Twist and MDR gene-associated proteins. It was identified that the expression levels of Twist, TOPO IIα, MRP and P-gp were upregulated and LRP was downregulated in human breast cancer tissues, which was consistent with the expression of these proteins in the Taxol®-resistant MCF-7 cell model. Notably, the overexpression of Twist in 293 cells increased the resistance to Taxol®, Trichostatin A and 5-fluorouracil, and also upregulated the expression of MRP and P-gp. Taken together, these data demonstrated that Twist may promote drug resistance in cells and cancer tissues through regulating the expression of MDR gene-associated proteins, which may assist in understanding the mechanisms of action of Twist in drug resistance.

Ruxolitinib sensitizes ovarian cancer to reduced dose Taxol, limits tumor growth and improves survival in immune competent mice.

BackgroundChemotherapy initially reduces the tumor burden in patients with ovarian cancer. However, tumors recur in over 70% of patients, creating the need for novel therapeutic approaches.MethodsWe evaluated Ruxolitinib, an FDA-approved JAK 1/2 kinase inhibitor, as a potential adjunctive therapy for use with low-dose Taxol (Paclitaxel) by assessing the impact on in vitro proliferation and colony formation of ID8 cells or human TOV-112D ovarian cancer cells, as well as flow cytometric measurement of surface markers associated with cellular stress and stemness by ID8 cells. The syngeneic ID8 murine model of ovarian cancer was used to assess the impact of Ruxolitinib and Taxol, individually and in combination, on tumor initiation and growth, as well as capacity to extend survival.ResultsRuxolitinib (≤10 μM) sensitized both ID8 and TOV-112D cells to low concentrations of Taxol (≤5 nM), limiting cell proliferation and colony formation in vitro. Mechanistically, we demonstrated that Taxol induced expression of stress and stemness markers including GRP78 and CD133 was significantly reduced by addition of Ruxolitinib. Finally, we demonstrated that a single administration of a low-dose of Taxol (10 mg/Kg) together with daily Ruxolitinib (30 mg/Kg; which is equivalent to plasma concentrations of ∼ 0.01 μM steady-state) limited ID8 tumor growth in vivo and significantly extended median survival up to 53.5% (median 70 v 107.5 days) as compared to control mice.ConclusionTogether, these data support the use of Ruxolitinib in combination with low-dose Taxol as a therapeutic approach with the potential for improved efficacy and reduced side effects for patients with recurrent ovarian cancer.

DNA ploidy and S-phase fraction analysis in peritoneal carcinomatosis from ovarian cancer: correlation with clinical pathological factors and response to chemotherapy.

ObjectiveWe investigated the correlation between ploidy or S-phase fraction (SPF) and the clinical pathological characteristics of patients with peritoneal carcinomatosis from ovarian cancer. We also assessed their relation with the in vivo and in vitro response to several chemotherapeutic agents.Patients and methodsFifty-three patients with peritoneal carcinomatosis from ovarian cancer were enrolled. Frozen tumor tissue was dissociated by a detergent–trypsin method, and the resulting cell suspension was stained with RNase A and propidium iodide. Samples were then analyzed for ploidy and SPF by flow cytometry. Fresh tumor tissue was dissociated by enzymatic digestion, and cells were exposed to different concentrations of cisplatin, adriamycin, carboplatin, gemcitabine and taxol for 72 hours. In vitro drug sensitivity was then measured using the sulforhodamine B assay.ResultsNo significant correlation was found between ploidy or SPF and patient characteristics, even though primary carcinomas were mainly hyperdiploid and more proliferative than recurrent tumors. SPF differed significantly among ploidy categories (P=0.01), and high SPF was associated with short-term survival (P=0.48). Patients with multiploid tumors were the most resistant to platinum-based chemotherapy, whereas those with hyperdiploid tumors were the most responsive. In vitro multiploid tumors were the least sensitive, while hypodiploid samples showed the highest sensitivity to the tested drugs. Sensitivity to adriamycin was significantly correlated with ploidy (P=0.03), whereas sensitivity to taxol was correlated with SPF (P=0.04).ConclusionOur results indicate that ploidy and SPF could facilitate the choice of therapy for patients with peritoneal carcinomatosis.

Improving 10-deacetylbaccatin III-10-\u03b2-O-acetyltransferase catalytic fitness for Taxol production

The natural concentration of the anticancer drug Taxol is about 0.02% in yew trees, whereas that of its analogue 7-β-xylosyl-10-deacetyltaxol is up to 0.5%. While this compound is not an intermediate in Taxol biosynthetic route, it can be converted into Taxol by de-glycosylation and acetylation. Here, we improve the catalytic efficiency of 10-deacetylbaccatin III-10-O-acetyltransferase (DBAT) of Taxus towards 10-deacetyltaxol, a de-glycosylated derivative of 7-β-xylosyl-10-deacetyltaxol to generate Taxol using mutagenesis. We generate a three-dimensional structure of DBAT and identify its active site using alanine scanning and design a double DBAT mutant (DBATG38R/F301V) with a catalytic efficiency approximately six times higher than that of the wild-type. We combine this mutant with a β-xylosidase to obtain an in vitro one-pot conversion of 7-β-xylosyl-10-deacetyltaxol to Taxol yielding 0.64 mg ml−1 Taxol in 50 ml at 15 h. This approach represents a promising environmentally friendly alternative for Taxol production from an abundant analogue.

Microwave-assisted extraction of Taxol and 10-Deacetyl baccatin III from the leaves and branches of red pine (Taxus wallichiana Zucc.)

Taxol has been by far the most well-known worldwide as an effective anticancer natural drug. With the great treatment abilities at low concentration, Taxol is a considerable interest of many scientists in various fields. The commercial products of Taxol can be isolated directly from Taxus species or can be synthesized from 10-deacetylbaccatin III (10-DAB III) or baccatin III (BC III), which are known as precursors of Taxol, by using semisynthetic methods. In this study, the extraction of Taxol and 10-DAB III from the leaves and branches of red pine cultivated in Lam Dong Province, Vietnam was carried out. Some traditional methods such as Soxhlet, maceration as well as the modern methods such as microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE) were used to extract and evaluate the extraction efficiency. The concentration of 10-DAB III experienced at over 90% as compared to maceration and the amount of Taxol accounted for approximately 80% of Soxhlet. MAE was thus more suitable for recovering both Taxol and 10-DAB III than the others because of its short time and less solvent consumption. Besides, four parameters including solvent nature (MeOH and EtOH), extraction time, material/solvent ratio (1:10, 1:15, 1:20 and 1:25) and microwave power (40W, 240W and 440W) were investigated the effects of these elements on the content of 10-DAB III and Taxol. The results illustrated that the optimal conditions providing 95.85% 10-DAB III were as follows: 240W, 1:15 ratio and 20 minutes for extraction. To get the highest amount of Taxol (79.83%), extraction was subjected at these conditions concluding 40W, 1:25 ratio and 20 minutes. Diaion, NP-silicagel were used to enrich taxol and 10-DAB III from methanol extract and chloroform extract, respectively. The highest concentration of Taxol and 10-DAB III constituted at 0.64% and 19.76% with NP-silicagel (PE: aceton, 7:3).

Overexpression of caveolin-1 reduces Taxol resistance in human osteosarcoma cells by attenuating PI3K-Akt-JNK dependent autophagy.

Caveolin-1 (CAV-1), which is an oncoprotein and a tumor suppressor, is highly expressed in normal osteoblasts. Although researchers have investigated its role in human osteosarcoma, the mechanism of caveolin-1 action in osteosarcoma remains unknown. In the present study, Saos-2 and U-2 OS cells were cultured with a continuous induction protocol of gradually increasing Taxol concentration for 6 months to establish drug-resistant cell lines. CAV-1 expression levels in osteosarcoma cells were detected via western blotting and quantitative polymerase chain reaction. CAV-1 knockdown was achieved using a short hair-pin RNA lentivirus vector, and cell viability was analyzed by MTT assay. The effect of caveolin-1 on autophagy was investigated, and the downregulation of caveolin-1 and increased autophagy was identified in Taxol-resistant osteosarcoma cells. In addition, the results of the present study demonstrated that downregulation of caveolin-1 promotes autophagy and induces osteosarcoma cell resistance to Taxol. Notably, overexpression of CAV-1 resensitized drug-resistant cells to Taxol via declined autophagy. In conclusion, CAV-1 was demonstrated to be downregulated in Taxol-resistant osteosarcoma cells, and overexpression of CAV-1 in human osteosarcoma cells suppressed Taxol resistance by attenuating PI3K-Akt-JNK-dependent autophagy. The present findings suggest that further investigation into CAV-1's role in Taxol resistance is warranted. In the future, detection of CAV-1 may be used as an indicator to evaluate the treatment and prognosis of patients with osteosarcoma.

A Combination Therapy with Baicalein and Taxol Promotes Mitochondria-Mediated Cell Apoptosis: Involving in Akt/β-Catenin Signaling Pathway.

Baicalein, a major flavonoid, possesses anticancer and anti-inflammatory activity. The aim of the study is to explore the efficiency of combination therapy with baicalein and taxol, as well as the molecular mechanism on antitumor activity. Human ovarian cancer cells were treated with different concentration of baicalein for 48 h, and cell viability was determined by MTT assay. Baicalein inhibited cell proliferation of ovarian cancer cells, and IC50 value of baicalein in A2780 cells, SKOV3 cells, and OVCAR cells was 46.23, 60.68, and 38.03 μM, respectively. The ovarian cancer cells were treated with 10 μM of baicalein combined with increasing concentration of taxol for 48 h, and the results demonstrated that combination therapy with baicalein and taxol had much higher antitumor effects compared with the monotherapy. The molecular mechanisms involving in combination therapy promoted the caspase-3 activity then leading to cleavage of poly-ADP-ribose polymerase, which increased the cell apoptosis of ovarian cancer cells. Moreover, Z-VAD-FMK treatment partially decreased the baicalein-induced proliferation inhibition in human ovarian cancer cells. Furthermore, baicalein induced apoptosis through activation of the activities of caspase-3,-9, and increased cytoplasmic cytochrome C release. Importantly, baicalein inhibited the growth of A2780 cells by inhibiting Akt/β-catenin signaling pathway. In conclusion, our result revealed that baicalein combinated with taxol at low concentrations could exert synergistic antitumor effects in ovarian cancer cells through mitochondria-mediated cell apoptosis and Akt/β-catenin signaling pathway. Baicalein has a promising potential to be developed as an antitumor compound, and combination therapy of baicalein and taxol exhibits an antitumor potential in clinical therapy for human ovarian cancers.

Silencing Op18/stathmin by RNA Interference Promotes the Sensitivity of Nasopharyngeal Carcinoma Cells to Taxol and High-Grade Differentiation of Xenografted Tumours in Nude Mice.

Nasopharyngeal carcinoma (NPC) is a refractory tumour, and chemotherapy is one of the primary treatment modalities. Oncoprotein 18 (Op18)/stathmin is a conserved small cytosolic phosphoprotein and highly expressed in tumours, which plays a vital role in maintaining the malignant phenotype of tumours. Taxol is a clinically widely used chemotherapeutic agent for a broad range of taxol-resistant tumours. This study showed that Op18/stathmin silencing by RNA interference (RNAi) combined taxol cooperatively improved cellular apoptosis in CNE1 cells mainly via initiating endogenous death receptor pathway, impaired the capabilities of cellular proliferation and cellular migration and down-regulated the half maximal inhibitory concentration (IC50 ) of taxol, meanwhile decreased the expression of the upstream extracellular regulated kinase 1 (ERK1) in vitro. Evidence also showed that taxol cytotoxicity was markedly augmented for Op18/stathmin RNAi in other NPC cells. In vivo animal experiments have demonstrated that early combination of Op18/stathmin silencing and taxol evidently inhibited tumourigenicity of CNE1 cells and growth of xenografted tumours in nude mice. Remarkably, silencing Op18/stathmin by RNAi still promoted transformation of late-stage CNE1 cells in NPC-xenografted tumours from moderately to highly differentiated and inhibited the pleiotropic cytokine interleukin-10 (IL-10) autocrine by transplanted tumours. These findings suggest that silencing Op18/stathmin by RNAi promotes chemosensitization of NPC to taxol and reverses malignant phenotypes of NPC, which provides a new clue for treating drug-resistant tumours.