Polysaccharide of sunflower (Helianthus annuus L.) stalk pith inhibits cancer proliferation and metastases via TNF-α pathway.

The decoctions of sunflower (Helianthus annuus L. HAL) stalk pith have been used to treat advanced cancer, and polysaccharide of sunflower stalk pith (HSPP) was key ingredient of the decoctions. To forage specially structured HSPP with anti-tumor effects and to uncover its mechanisms of anticancer activity, syngeneic mouse model of lung carcinoma metastasis was established and the HSPP was found to contain long-chain fatty acid. Encouragingly, the mean survival of the polysaccharide group (47.3 ± 12.8 d) and its sub-fractions group HSPP-4 (50.7 ± 13.0 d) was significantly increased compared with control group (38.7 ± 12.7 d) or positive control group (41.8 ± 13.4 d), (n = 20, P < 0.01 vs. the control group or positive control group). Furthermore, the HSPP exerted inhibitory effects on the tumor cells' metastasis. Eventually, it is postulated that the polysaccharide could inhibit tumor proliferation and metastasis by reduction of TNF-α from the macrophage.

Synergistic effect of docetaxel and gambogic acid on bone metastasis of lung cancer.

INTRODUCTION: Gambogic acid (GA) as an active compound isolated from Gamboge, have been investigated for many years and proved to be a promising natural anticancer agent for clinical treatment. This study aimed to investigate the inhibitory effect of docetaxel (DTX) combined with gambogic acid on bone metastasis of lung cancer. METHODS: The anti-proliferation effect of the combination of DTX and GA on Lewis lung cancer (LLC) cells was determined by MTT assays. The anticancer effect of the combination of DTX and GA on bone metastasis of lung cancer in vivo was explored. Evaluation of the efficacy of drug therapy was performed by comparing the degree of bone destruction and the pathological section of bone tissue of the treated mice with that of the control mice. RESULTS: In vitro cytotoxicity, cell migration, and osteoclast-induced formation assay showed that GA enhanced the therapeutic effect of DTX in Lewis lung cancer cell with a synergistic effect. In an orthotopic mouse model of bone metastasis, the average survival of the DTX+GA combination group (32.61d±1.06 d) was significantly increased compared with that of the DTX group (25.75 d±0.67 d) or GA group (23.99 d±0.58 d), *P<0.01. CONCLUSION: The combination of DTX and GA has synergistic effect and resulted in more effective inhibition of tumor metastasis, providing a strong preclinical rationale for the clinical development of the DTX+GA combination for treating bone metastasis of lung cancer.

Preparation, characterization and in vitro activity of a docetaxel-albumin conjugate.

Docetaxel is one of the most effective anticancer drugs. However, the current formulation of docetaxel contains Tween 80 and ethanol as the solvent, which can cause severe side effects. Consequently, the development of new type of formulation of docetaxel with high efficiency and low side effects is a very important issue. In this study, we explored the covalent linking of docetaxel and albumin via one organic linker. 6-Maleimidocaproic acid was applied to link the C2' hydroxyl group of docetaxel with the cysteine-34 of albumin to obtain 1:1 docetaxel-albumin conjugate. The synthesized conjugate can control the release of docetaxel in the bovine serum. Furthermore, in vitro cell cytotoxicity experiments indicated that the docetaxel-albumin conjugate have high activities for human prostate cancer cell line PC3 and human breast cancer cell line MCF-7. The present study provides a valuable strategy for further development of a new type of docetaxel-albumin prodrug.

Tumor targeting with docosahexaenoic acid-conjugated docetaxel for inhibiting lung cancer metastasis to bone.

Docetaxel (DTX) is currently used as a first- or second-line drug treatment for patients with lung cancer, however, it is less effective for the treatment of patients with bone metastasis of lung cancer. This is primarily due to the fact that docetaxel is nonspecific. In the present study, docosahexaenoic acid (DHA) was selected as a tumor-targeting ligand, and DHA-conjugated DTX (DTX-DHA) was prepared for inhibiting lung cancer metastasis to bone. The anti-cancer activity assay revealed that DTX-DHA exhibited a similar antitumor efficacy to DTX in vitro. The maximum tolerated dose of DTX-DHA was increased compared with that of DTX. The present study results indicated that DTX-DHA exhibited an improved inhibition efficacy of lung cancer metastasis to bone in comparison with DTX in vivo. Encouragingly, the mean survival time of the DTX-DHA group (30.60 days) was increased compared with the DTX group (26.10 days; P<0.01). Furthermore, the results of cell migration and osteoclast-induced formation assays suggested that DTX-DHA inhibited lung cancer metastasis to bone primarily by affecting lung cancer cell migration. These results indicate that DTX-DHA may exhibit a potential therapeutic effect against lung cancer metastasis to bone.

Docetaxel-loaded Bovine Serum Albumin Nanoparticles Conjugated Docosahexaenoic Acid for Inhibiting Lung Cancer Metastasis to Bone.

BACKGROUND: Cancer is one of the severest diseases in the world, and lung cancer is one of the five common cancers causing thousands of deaths every year. Moreover, most of the lung cancer patients die because of bone metastasis. METHODS: This research was conducted with the aim of developing novel nanoparticles (NPs) of docetaxel (DTX) loaded bovine serum albumin (BSA) conjugated docosahexaenoic acid (DHA) using an emulsion/solvent evaporation method for inhibiting lung cancer metastasis to bone. The in vitro drug release of the DTX-DHA-BSA-NPs showed that the nanoparticles released in a sustained and controlled manner contributed to continual fight against cancer cells. The study results revealed that the DTX-DHA-BSA-NPs had higher antitumor efficacy in comparison with the DTXBSA- NPs or DTX in vitro. RESULT: The study results also showed that the DTX-DHA-BSA-NPs had higher inhibiting efficacy of lung cancer metastasis to bone in comparison with the DTX-BSA-NPs or DTX in vivo. Furthermore, the mean survival time was longer with DTX-DHA-BSA-NPs (24.40 d) than that of DTX (20.95 d). In consideration of these results, the DTXDHA- BSA-NPs may hold potential for bone metastasis of lung cancer treatment.

Preparation, characterization, and antitumor activities of folate-decorated docetaxel-loaded human serum albumin nanoparticles.

CONTEXT: Docetaxel is now a major antitumor drug in clinical use for the treatment of a variety of tumors. The ethanol/Tween 80 solvent required in the formulation to increase the docetaxel solubility is at least partly responsible for the hypersensitivity reaction, decreased uptake by tumor tissue, and increased exposure to other body compartments. OBJECTIVE: The present study was aimed at developing hydrosoluble DTX-FA-HSANPs targeting tumor cells and to investigate antitumor activities of the nanoparticles. MATERIALS AND METHODS: The DTX-HSANPs were prepared using a desolvation technique and the carboxylic groups of NHS-folate were conjugated with the amino groups of the human serum albumin nanoparticles, and studied their size and zeta potential, drug loading efficiency, surface morphology, release properties in vitro, and antitumor activities. RESULTS: The spherical nanoparticles obtained were negatively charged with a zeta potential of about -30 mV and characterized around 150 nm with a narrow size distribution. Drug loading efficiency was approximately 17.2%. The folate-decorated nanoparticles targeted a human hepatoma cell line effectively. The in vitro drug release of DTX-FA-HSANPs in the first 96 h corresponded with the following equation: Q = 18.87851 - 0.13866t + 0.21276t² - 0.00704t³ + 0.0000847854t4 - 0.00000034991t5 (R² = 0.98155). Moreover, the in vitro antitumor activities of DTX-FA-HSANPs were close to the activities of the positive control (docetaxel). The in vivo inhibition ratios of DTX-FA-HSANPs and docetaxel were 66.2% and 59.5%, respectively, at a dose of 5 mg/kg. DISCUSSION AND CONCLUSION: In light of the observed antitumor activities, it would be of considerable interest to collect sufficient data for the clinical application of docetaxel-loaded nanoparticles.

Econazole Nitrate Induces Apoptosis in MCF-7 Cells via Mitochondrial and Caspase Pathways.

Econazole nitrate (EN), a synthetic compound, is now in use as a routine antifungal drug. EN was shown to have antitumor effect, the tumor cell killing mechanisms, however, remain unclear. In this research, the apoptosis-inducing effect of EN on MCF-7 cells was investigated. The results showed that EN inhibited the proliferation of MCF-7 cells in a time- and dose-dependent manner by MTT method and colony forming assay. MCF-7 cells treated with EN showed typical characteristics of apoptosis including the morphological changes and DNA fragmentation. Meanwhile, the loss of mitochondrial membrane potential was showed by flow cytometry. In addition, western blot analysis showed that EN resulted in the decrease expression of procaspase-3, procaspase-9 and bcl-2. In conclusion, these findings suggest that EN may be an effective way for treating human breast cancer. The anti-tumor mechanisms of EN might involve mitochondrial and caspase pathways.

Characterization and pharmacokinetics of coenzyme Q10 nanoparticles prepared by a rapid expansion of supercritical solution process.

Coenzyme Q10 (CoQ10) has been found to be effective in cardiovascular diseases and neurodegenerative diseases. However, the extremely poor solubility of CoQ10 in water is hampering its bioavailability as a therapeutic agent. To overcome solubility problem, we micronized the CoQ10 powder to the nanometer level by the supercritical solution (RESS) process, which does not employ any toxic organic solvent. The obtained CoQ10 nanoparticles were 147.9 +/- 27.3nm in diameter and their physicochemical properties were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), liquid chromatography-mass spectrometry (LC-MS), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) analyzes. Moreover, the pharmacokinetics of the CoQ10 nanoparticles, in comparison with the unprocessed CoQ10 powder, were investigated in rats. From the results of physicochemical and pharmacokinetic studies, the CoQ10 nanoparticles had high solubility in water and possessed less crystalline structure, which can enhance the bioavailability of CoQ10, and provide a water-soluble solid dosage form of CoQ10.

Involvement of mitochondrial permeability transition pore opening in 7-xylosyl-10-deacetylpaclitaxel-induced apoptosis.

7-Xylosyl-10-deacetylpaclitaxel is a natural hydrophilic paclitaxel derivative. It has long been used in Chinese clinics to treat cancer. In order to further explore the underlying intracellular target of 7-xylosyl-10-deacetylpaclitaxel towards the PC-3 cell line, the ultra-structural morphology of mitochondria, the intracellular Ca (2+), the intracellular ATP, the intracellular hydrogen peroxide and pro-apoptotic Bax and Bcl-2 protein expression were measured. Additionally, the changes of mitochondrial morphology and membrane potential ( ΔΨm) were analyzed by atomic force microscopy (AFM) and flow cytometry, respectively. Our results suggest that the intracellular target of 7-xylosyl-10-deacetylpaclitaxel may be the mitochondrial permeability transition pore (mPTP). To further evaluate this hypothesis, we assessed the effect of a specific mPTP inhibitor (cyclosporine A) on the toxic action of 7-xylosyl-10-deacetylpaclitaxel. The 7-xylosyl-10-deacetylpaclitaxel-induced decrease in mitochondrial inner transmembrane potential (ΔΨm) was abolished by the addition of cyclosporine A (CsA) in PC-3 cells, indicating that 7-xylosyl-10-deacetylpaclitaxel may target mPTP. Furthermore, treatment with 7-xylosyl-10-deacetylpaclitaxel increased ROS levels in PC-3 cells. This effect was counteracted by 10 µM cyclosporine A. These data indicate that oxidative damage is involved in mPTP.

Antitumor activities of extracts and compounds from water decoctions of Taxus cuspidata.

Water decoctions from the leaves of Taxus cuspidata are used in traditional Chinese medicine to treat cancer, suggesting that water soluble constituents from these leaves may possess anticancer properties. Interestingly, hydrophilic paclitaxel derivatives, as opposed to paclitaxel itself, can be detected by high pressure liquid chromatography in water decoctions from these leaves. The remainder extracts, which are free of paclitaxel and hydrophilic paclitaxel derivatives, from the T. cuspidata leaves were investigated for antitumor activity in vivo and in vitro for the first time in this study. EE80B, 7-xylosyl-10-deacetylpaclitaxel and 7-xylosyl-10-deacetylpaclitaxel C displayed the most antitumor activity in vivo. However, in vitro studies with tumor cell lines showed that EE80B had a significantly smaller antitumor effect than paclitaxel. We hypothesize that water decoctions from T. cuspidata leaves exhibit antitumor effects in vivo, which may be aided by the activation of specific host mechanisms (e.g. stimulation of antitumor immunity) which are not present in vitro.

Transport of a hydrophilic paclitaxel derivative, 7-xylosyl-10-deacetylpaclitaxel, by human intestinal epithelial Caco-2 cells.

7-Xylosyl-10-deacetylpaclitaxel is an active compound used in traditional Chinese medicine to treat cancer. However, pharmacokinetic studies yielded low plasma concentrations of 7-xylosyl-10-deacetylpaclitaxel after its oral administration in preclinical trials. Therefore, we investigated whether the observed low oral bioavailability of this compound is due to poor absorption. We studied the transepithelial flux of 7-xylosyl-10-deacetylpaclitaxel using the human colonic cell line Caco-2 as a model and found out that its flux (at a concentration range of 0.5-20 µM) across the Caco-2 cell layer was linear with time for up to 3 hr. The apparent maximal concentration (K (M)) of the active efflux component was 93.4 µM. Verapamil (50 µM) and tetrandrine (25 µM) significantly decreased the active transport component. These data support the conclusion that rapid passive diffusion of 7-xylosyl-10-deacetylpaclitaxel through the intestinal epithelium is partially counteracted by the action of an outwardly directed efflux pump, presumably P-glycoprotein. The relatively high apparent permeability coefficient ( P(app)) for the apical to basolateral 7-xylosyl-10-deacetylpaclitaxel transport (16.3 ± 6.3 × 10 (-6) cm/s; n = 3) suggests that the drug may still be effectively absorbed in the intestinal tract.

Anti-proliferative and pro-apoptotic effect of CPT13, a novel camptothecin analog, on human colon cancer HCT8 cell line.

10-(2-pyrazolyl-ethoxy)-(20S)-camptothecin (CPT13) is a novel semi-synthetic analogue of camptothecin, our previous report had shown that it possessed higher in vitro cytoxicity activity towards human colon cancer HCT8 cell line than topotecan. In this study, the anti-proliferative effect of CPT13 on HCT8 cell line in vitro was analyzed. In order to further explore the underlying mechanism of cell growth inhibition of CPT13 towards HCT8 cell line, the cell cycle distribution, apoptosis proportion, the nuclei morphological changes and caspase-8 and caspase-3 activities were measured. Additionally the changes of mitochondrial morphology and membrane potential (DeltaPsim) were analyzed by atomic force microscopy (AFM) and flow cytometry, respectively. The results showed that CPT13 inhibited HCT8 cell growth by causing cell cycle arrest at G2/M transition and induced apoptosis, as evidenced by the typical apoptotic morphology such as condensation and fragmentation of nuclei and formation of apoptotic bodies. The changes of mitochondrial morphology, dose-dependently decrease in DeltaPsim and the enhancement of caspase-8 and caspase-3 activities were observed in different concentrations of drug treatment group. Our results suggest that CPT13 induces apoptosis by alternations of mitochondrial transmembrane depolarization, activation of caspase-8 and caspase-3. Therefore, CPT13 appears to be a potent drug against human colon cancer via induction of apoptosis and may be used as an alternative drug to therapy cancer.

Activation of the mitochondria-driven pathway of apoptosis in human PC-3 prostate cancer cells by a novel hydrophilic paclitaxel derivative, 7-xylosyl-10-deacetylpaclitaxel.

Paclitaxel, a natural product originally isolated from Taxus brevifolia, belongs to the most successful anticancer drugs. Nevertheless, its poor water solubility represents a considerable disadvantage in clinical use, and novel derivatives with improved pharmacological features are required. We isolated 7-xylosyl-10-deacetylpaclitaxel from Taxus chinensis, which reveals higher water solubility than paclitaxel. This compound induced mitotic cell cycle arrest and apoptosis as measured by flow cytometry, DNA laddering, and transmission electron microscopy. Pro-apoptotic Bax and Bad protein expression was up-regulated and anti-apoptotic Bcl-2 and Bcl-XL expression down-regulated, which lead to a disturbance of the mitochondrial membrane permeability and to the activation of caspase-9. In turn, caspase-9 activated downstream caspases-3 and -6, but not caspase-8. Bid was also activated by caspase-3. Reversely, treatment with a caspase-10-specific inhibitor could not protect PC-3 cells from 7-xylosyl-10-deacetyl-paclitaxel-triggered apoptosis. Moreover, 7-xylosyl-10-deacetylpaclitaxel had no effect on the expression of CD95 and NF-kappaB proteins, indicating that apoptosis was induced through the mitochondrial-dependent pathway in PC-3 cells.

Separation of 7-xylosyl-10-deacetyl paclitaxel and 10-deacetylbaccatin III from the remainder extracts free of paclitaxel using macroporous resins.

The separation and enrichment of 10-deacetylbaccatin III (10-DAB III) and 7-xylosyl-10-deacetyl paclitaxel were studied on seven macroporous resins with special structures. The performance of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III on macroporous resins including AB-8, ADS-17, ADS-21, ADS-31, ADS-8, H1020 and NKA-II was compared according to their adsorption and desorption properties. AB-8 provided a much higher adsorption capacity for 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III than other resins, and its adsorption data fitted well to the Langmuir and Freundlich isotherm. According to the adsorption and desorption capacities and the adsorption isotherms, AB-8 demonstrated a remarkable capability for the preparative separation of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III from the remainder extracts free of paclitaxel. In order to optimize parameters of separation, dynamic adsorption and desorption experiments were carried out on the columns packed with AB-8 resin. The optimal conditions were: the processing volume 15 BV; concentrations of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III in feed solution 0.0657 mg/mL and 0.1494 mg/mL; flow rate 1 mL/min; temperature 35 degrees C. The gradient elution program was as follows: 30% ethanol for 3 BV, then 80% of ethanol for 6 BV, flow rate 1 mL/min. After the AB-8 resin treatment, the contents of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III in the product had increased from 0.053% and 0.2% to 3.34% and 1.69%, which were 62.43-fold and 8.54-fold of those in the untreated extracts, respectively, and the recoveries of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III were 85.85% and 52.78%. The performance achieved good separation and higher recovery of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III from remainder extracts free of paclitaxel by using AB-8 resin. It is a fast and effective method for the separation and enrichment of 7-xylosyl-10-deacetyl paclitaxel and 10-DAB III.