Aspartic acid derivatized hydroxylated fullerenes as drug delivery vehicles for docetaxel: an explorative study

Synthetic lipoproteins based on apolipoprotein E coupled to fullerenol have anti-atherosclerotic properties

BACKGROUND

Apolipoprotein E (apoE) is an anti-atherosclerotic protein associated with almost all plasma lipoproteins. Fullerenol (Full-OH) contains the fullerene hydrophobic cage and several hydroxyl groups that could be derivatized to covalently bind various molecules. Herein, we aimed to produce fullerenol-based nanoparticles carrying apoE3 (Full-apoE) and test their anti-atherosclerotic effects.

METHODS

Full-apoE nanoparticles were obtained from Full-OH activated to reactive cyanide ester fullerenol derivative that was further reacted with apoE protein. To test their effect, the nanoparticles were administered to apoE-deficient mice for 24 h or 3 weeks. ApoE part of the nanoparticles was determined by Western Blot and quantified by ELISA. Atherosclerotic plaque size was evaluated after Oil Red O staining and the gene expression was determined by Real-Time PCR.

RESULTS

Full-apoE nanoparticles were detected mainly in the liver, and to a lesser extent in the kidney, lung, and brain. In the plasma of the Full-apoE-treated mice, apoE was found associated with very-low-density lipoproteins and high-density lipoproteins. Treatment for 3 weeks with Full-apoE nanoparticles decreased plasma cholesterol levels, increased the expression of apolipoprotein A-I, ABCA1 transporter, scavenger receptor-B1, and sortilin, and reduced the evolution of the atheromatous plaques in the atherosclerotic mice.

CONCLUSIONS

In experimental atherosclerosis, the administration of Full-apoE nanoparticles limits the evolution of the atheromatous plaques by decreasing the plasma cholesterol level and increasing the expression of major proteins involved in lipid metabolism. Thus, they represent a novel promising strategy for atherosclerosis therapy.

Ultrasensitive biosensing platform based on luminescence quenching ability of fullerenol quantum dots

An ultrasensitive biosensing platform for DNA and ochratoxin A (OTA) detection is constructed based on the luminescence quenching ability of fullerenol quantum dots (FOQDs) for the first time. As the surface of FOQDs is largely covered by hydroxyl groups, stable colloidal suspension of FOQDS in aqueous solution can be obtained, which is very advantageous for application in biosensing compared to nano-C60. FOQDs can effectively quench the fluorescence of dyes with different emission wavelengths that are tagged to bioprobes to an extent of more than 87% in aqueous buffer solution through a PET mechanism. Moreover, the nonspecific quenching of the fluorescent dyes (not bound to bioprobes) caused by FOQDs is negligible, so the background signal is extremely low which is beneficial for improving the detection sensitivity. Based on the π-π stacking interaction between FOQDs and bioprobes, such as single-stranded (ss) DNA and aptamers, a nucleic acid assay with a detection of limit of 15 pM and a highly sensitive OTA assay with a detection limit of 5 pg mL-1 in grape juice samples are developed through the simple "mix and measure" protocol based on luminescence quenching-and-recovery. This is the first demonstration of constructing biosensors utilizing the luminescence quenching ability of FOQDs through a PET mechanism, and the pronounced assay performance implies the promising potential of FOQDs in biosensing.

Inclusion Complex of Docetaxel with Sulfobutyl Ether β-Cyclodextrin: Preparation, In Vitro Cytotoxicity and In Vivo Safety

Docetaxel (DTX), as a first-line anti-tumor drug, has been studied for decades for its diverse bioactivities. However, DTX presents poor solubility in water, low bioavailability and serious toxic side effects which has hindered its application in the clinic. To address these problems, docetaxel-sulfobutyl ether-β-cyclodextrin inclusion complex (DTX-SBE-β-CD) was prepared successfully by saturated aqueous solution method. Sulfobutyl ether β-cyclodetrin (SBE-β-CD) is used as delivery material. For this study, the inclusion complex of docetaxel with sulfobutyl ether β-cyclodetrin (DTX-SBE-β-CD) was prepared and optimized its properties to enhance the cytotoxicity of cancer cells. A large number of physical characterization results showed that DTX-SBE-β-CD inclusion complex was successfully prepared by saturated aqueous solution method. DTX-SBE-β-CD inclusion complex was optimized by Central Composite Design. DTX-SBE-β-CD had an inhibitory effect on the in vitro determination of MCF-7 and HepG2 cells by MTT assay. Pharmacokinetic studies were carried out on male Sprague–Dawley rats by tail injection, including the distribution, metabolism and elimination of DTX-SBE-β-CD in vivo. In the experimental study of inhibition of cancer cells, DTX and DTX-SBE-β-CD showed apparent concentration-dependent inhibitory actions on tumor cells and the inhibition of DTX-SBE-β-CD group was more obvious.

Aspartic acid tagged carbon nanotubols as a tool to deliver docetaxel to breast cancer cells: Reduced hemotoxicity with improved cytotoxicity

The present study aimed to explore the potential of hydroxylated carbon nanotubes (CNTnols) conjugated with aspartic acid for the delivery of docetaxel (DTX) to breast cancer cells. The conjugate was well-characterized by FT-IR, NMR, XRD and FE-SEM. The nanoconjugate offered a hydrodynamic diameter of 86.31 ± 1.02 nm, with a PDI of 0.113 and zeta potential of -41.6 ± 0.17 mV. The designed nanosystem offered a controlled & pH dependent release vouching release of drug in the cancerous cytosol, not in blood, assuring delivery of the pay-load to the site of action. The carriers offered substantial hemocompatibility and lower plasma protein binding, ensuring more drug available at the site of action. The in-vitro cell viability studies in MDA MB-231 cells inferred approx. 2.8 times enhancement in the cytotoxicity potential of the conjugate vis-à-vis plain drug. Pharmacokinetic studies also corroborated the superiority of the designed nanoconjugate in terms of enhanced bioavailable fractions, reduced clearance and longer bioresidence to that of plain docetaxel. The present studies, successfully provide a workable nanomedicine, loaded with a BCS class-IV drug, for improved efficacy and safety in breast cancer.

Advances in Therapeutic Implications of Inorganic Drug Delivery Nano-Platforms for Cancer

Numerous nanoparticles drug delivery systems for therapeutic implications in cancer treatment are in preclinical development as conventional chemotherapy has several drawbacks. A chemotherapeutic approach requires high doses of chemotherapeutic agents with low bioavailability, non-specific targeting, and above all, development of multiple drug resistance. In recent years, inorganic nano-drug delivery platforms (NDDPs; with a metal core) have emerged as potential chemotherapeutic systems in oncology. One of the major goals of developing inorganic NDDPs is to effectively address the targeted anti-cancer drug(s) delivery related problems by carrying the therapeutic agents to desired tumors sites. In this current review, we delve into summarizing the recent developments in targeted release of anti-cancer drugs loaded in inorganic NDDPs such as mesoporous silica nanoparticles, carbon nanotubes, layered double hydroxides, superparamagnetic iron oxide nanoparticles and calcium phosphate nanoparticles together with highlighting their therapeutic performance at tumor sites.

pH-Sensitive Co-Adsorption/Release of Doxorubicin and Paclitaxel by Carbon Nanotube, Fullerene, and Graphene Oxide in Combination with N-isopropylacrylamide: A Molecular Dynamics Study

Nanotechnology based drug delivery systems for cancer therapy have been the topic of interest for many researchers and scientists. In this research, we have studied the pH sensitive co-adsorption and release of doxorubicin (DOX) and paclitaxel (PAX) by carbon nanotube (CNT), fullerene, and graphene oxide (GO) in combination with N-isopropylacrylamide (PIN). This simulation study has been performed by use of molecular dynamics. Interaction energies, hydrogen bond, and gyration radius were investigated. Results reveal that, compared with fullerene and GO, CNT is a better carrier for the co-adsorption and co-release of DOX and PAX. It can adsorb the drugs in plasma pH and release it in vicinity of cancerous tissues which have acidic pH. Investigating the number of hydrogen bonds revealed that PIN created many hydrogen bonds with water resulting in high hydrophilicity of PIN, hence making it more stable in the bloodstream while preventing from its accumulation. It is also concluded from this study that CNT and PIN would make a suitable combination for the delivery of DOX and PAX, because PIN makes abundant hydrogen bonds and CNT makes stable interactions with these drugs.

Fullerenol-Based Intracellular Delivery of Methotrexate: A Water-Soluble Nanoconjugate for Enhanced Cytotoxicity and Improved Pharmacokinetics

Derivatization of fullerenes to polyhydroxylated fullerenes, i.e., fullerenols (FLU), dramatically decreases their toxicity and has been reported to enhance the solubility as well as cellular permeability. In this paper, we report synthesis of FLU as nanocarrier and subsequent chemical conjugation of Methotrexate (MTX) to FLU with a serum-stable and intracellularly hydrolysable ester bond between FLU and MTX. The conjugate was characterized for physiochemical attributes, micromeritics, drug-loading, and drug-release and evaluated for cancer cell-toxicity, cellular-uptake, hemocompatibility, protein binding, and pharmacokinetics. The developed hemocompatible FL-MTX offered lower protein binding vis-à-vis naïve drug and substantially higher drug loading. The conjugate offered pH-dependent release of 38.20 ± 1.19% at systemic pH and 85.67 ± 3.39% at the cancer cell pH. FLU-MTX-treated cells showed significant reduction in IC₅₀ value vis-à-vis the cells treated with pure MTX. Analogously, the results from confocal scanning laser microscopy also confirmed the easy access of the dye-tagged FLU-MTX conjugate to the cell interiors. In pharmacokinetics, the AUC of MTX was enhanced by approx. 6.15 times and plasma half-life was enhanced by 2.45 times, after parenteral administration of single equivalent dose in rodents. FLU-MTX offered enhanced availability of drug to the biological system, meanwhile improved the cancer-cell cytotoxicity, sustained the effective plasma drug concentrations, and offered substantial compatibility to erythrocytes.

Development of novel biotinylated chitosan-decorated docetaxel-loaded nanocochleates for breast cancer targeting

The motive of study was to develop biotinylated chitosan (BI-CHI) decorated docetaxel (DTX) loaded nanocochleates (BI-CHI-DTX-NC) to achieve controlled drug release, improve bioavailability, targeted delivery and enhanced anticancer potency with the reduced systemic toxicity of DTX. The development involved the loading of DTX to nanocochleates (DTX-NC) through conversion of dimyristoylphosphatidylglycerol-sodium (DMPG-Na) and cholesterol bearing liposome on addition of calcium ions, followed by encapsulated DTX-NC with BI-CHI (BI-CHI-DTX- NC) and compared with DTX and DTX-NC. The release of DTX indicated strong pH dependence and implies strong hydrogen-bonding between nanocochleates and DTX. Formulated BI-CHI-DTX-NC demonstrated higher in-vitro anticancer activity in biotin over expressed human breast cancer MCF-7 cells. The targeting effect for the BI-CHI-DTX-NC was also demonstrated. The concentration of the drug needed for growth inhibition of 50% of cells in a designed time period (GI50) was 1.8 μg/ml for free DTX while it was decreased by 33.34% for the DTX-NC (1.2 μg/ml). Furthermore, the GI50 value of BI-CHI-DTX-NC was 0.2 μg/ml, i.e. an 88.89% decrease was observed as compared to DTX solution. Moreover, bioavailability of DTX from BI-CHI-DTX-NC was increased by 10-folds with longer circulation time and slower plasma elimination with low tissue distribution as compared to DTX solution. The results indicate that the BI-CHI-DTX- NC has the potential to be applied for targeting anticancer drug delivery.