Vitamin E-based nanomedicines for anti-cancer drug delivery

Paclitaxel-loaded TPGS enriched self-emulsifying carrier causes apoptosis by modulating survivin expression and inhibits tumour growth in syngeneic mammary tumours

Paclitaxel (PTX) in its commercial products exhibits adverse effects owing to excipients and also has poor oral bioavailability. Present work is directed towards development of tocopheryl polyethylene glycol succinate-assisted self-nanoemulsifying system (SEDDS) for oral delivery of PTX. Box-Behnken design of experiment was employed to optimize PTX-SEDDS and was characterized for droplet size (29.76 ± 2.64 nm), zeta potential (-21.46 ± 2.52 mV), PDI (0.177 ± 0.012), drug content (4.97 ± 0.98 mg), entrapment efficiency (98.33 ± 0.54%) and in vitro drug release (51.03 ± 2.23% PTX at 72 h). PTX-SEDDS exhibited IC₅₀; 1.58 ± 0.12 µM and a 52.46-folds higher cell uptake in MDA-MB-231 cells along with cellular and nuclear morphology changes. Significantly higher G₂M cell cycle arrest, apoptosis, mitochondrial membrane potential disruption and ROS production was exhibited by PTX-SEDDS in comparison to Taxol. Up-regulation of Bax, p21, cleaved-caspase 3, -caspase 9 and down-regulation of Bcl2 and survivin suggested apoptosis via intrinsic pathways. Pharmacokinetic study showed approximately 4-folds higher oral bioavailability of PTX-SEDDS than Taxol. Significant reduction in tumour volume and weight was observed in syngeneic mammary tumour in SD rats. Tumour histopathology and TUNEL assay showed apoptosis in tumour tissue. PTX-SEDDS caused low lung metastasis, and was safe and stable. Conclusively, PTX-SEDDS could be suitable option for oral delivery of PTX.

Vitamin E-based redox-sensitive salinomycin prodrug-nanosystem with paclitaxel loaded for cancer targeted and combined chemotherapy

Cancer stem cells (CSCs) can resist conventional chemotherapy to lead to cancer recurrence. For complete eradication of cancers, an effective CSCs therapeutic strategy should be developed to combine with conventional chemotherapy. In this work, a novel vitamin E-based redox-sensitive salinomycin (SAL, an inhibitor for CSCs) prodrug nanoparticles (TS NPs) and hyaluronic acid (HA)-coated TS NPs (HTS NPs) were fabricated to deliver paclitaxel (PTX) for cancer-targeted and combined chemotherapy. Both TS and HTS prodrug NPs had mean diameter of about 200 nm with uniform size distribution, excellent drug loading capacity for PTX, and glutathione-triggered SAL and PTX release profiles. The HTS prodrug NPs had enhanced cellular uptake efficiency over TS NPs due to CD44 receptor-mediated endocytosis, hence exerting stronger potency of SAL upon CSCs-enriched mammospheres formation and G₀/G₁ cell phase arresting. Cytotoxicity and 3D tumor spheroids assays demonstrated that both TS and HTS prodrug NPs themself can synergize with loaded PTX to maximize the chemotherapeutic effect. Obviously, the latter demonstrated a more potent anticancer efficacy due to improved intracellular drug delivery efficiency. These results suggested that the designed TS prodrug NPs, especially the coated HTS NPs can serve as an effective anti-CSCs strategy for cancer targeted and combination treatments.

Improved intestinal absorption of paclitaxel by mixed micelles self-assembled from vitamin E succinate-based amphiphilic polymers and their transcellular transport mechanism and intracellular trafficking routes

To ensure that antitumor drugs can be effectively transported across intestinal barrier and then quickly released in tumor cells, mixed polymeric micelles (Mix-PMs) were designed and fabricated by combining poly(2-ethyl-2-oxazoline)-vitamin E succinate (PEOz-VES) with TPGS1000 for enhancing intestinal absorption of paclitaxel. PEOz-VES exhibited an extremely low critical micelle concentration and negligible cytotoxicity. The Mix-PMs were characterized to have about 20 nm in diameter, uniform spherical morphology, high drug-loading content and sustained drug release profile with a retained pH-sensitivity. The results of the transport through Caco-2 cell monolayers and intestinal absorption revealed that Mix-PMs displayed higher transcellular transport efficiency compared with PEOz-VES micelles and Taxol^®. The possible mechanism of transcellular transport for Mix-PMs was elucidated to be mainly through clathrin- and caveolae/lipid rafts-mediated transcytosis. Confocal laser scanning micrographs revealed that late endosomes, lysosomes, endoplasmic reticulum, Golgi apparatus, and mitochondria were all involved in intracellular trafficking of Mix-PMs. The proteins involved in transcytosis of Mix-PMs and finally excreted were unraveled for the first time by the analysis of proteins in the basolateral media according to the proteomics method. Consequently, the fabricated mixed polymeric micelles may have great potential in enhancing intestinal absorption and accelerating drug release in tumor cells.

Lyophilized tablets for focal delivery of fluconazole and itraconazole through vaginal mucosa, rational design and in vitro evaluation

The present work deals with the rational design and in vitro evaluation of vaginal tablets for focal delivery of fluconazole (FLZ) and itraconazol (ITZ). Drug loaded liposomes with and without d-alpha-tocopheryl polyethylene glycol 1000 succinate (vit E TPGS) were prepared by direct sonication of the components and mixed with albumin to obtain albusomes. Tablets were obtained by direct compression of the lyophilized cake. The influence of vit E TPGS on size, zeta potential and entrapment efficiency (EE%) of liposomes and albusomes was evaluated. Tablet swelling and drug release were studied by in vitro assays. Vit E TPGS neither affected the zeta potential nor the EE% of liposomes and albusomes, but affected the liposomes size and the tablet disintegration time. A rapid erosion was observed for the tablets with the highest content of vitamin, while a slow swelling for those lacking the vitamin (swelling index = 57.76 ± 13.51%). A faster drug release profile was obtained for the former compared to the latter. The in vitro assay showed that FLZ diffused and solved in the vaginal fluid simulant while ITZ remained into the albusomes, which slowly released ITZ-albumin complex and ITZ-loaded liposomes, both suitable carriers for drug transport to deeper vaginal endothelium.

An Insight into Ginsenoside Metabolite Compound K as a Potential Tool for Skin Disorder

Ginsenosides are the major bioactive natural compounds derived from Panax ginseng. Several studies report the pharmaceutical benefits of several ginsenosides, including antidementia, antitumor, and anti-inflammatory activity. Biotransformations by gut microbiome contribute to the biological function of these ginsenosides. After ingestion ginsenosides are hydrolyzed to Rg2, Rg3, compound K, and others by human gut flora. Compound K is considered the representative active metabolite after oral administration of ginseng or ginsenosides. Various studies report the diverse biological functions of compound K, such as antitumor, antidiabetic, antiallergic, and anti-inflammatory activity. Recent clinical trial and in vitro studies demonstrate the antiaging activities of ginsenosides in human skin. Ginsenosides have been considered as an important natural dermatological agent. In this review, we will cover the modern tools and techniques to understand biotransformation and delivery of compound K. Also the biological function of compound K on skin disorder and its potential dermatological application will be discussed.

Paclitaxel-loaded redox-sensitive nanoparticles based on hyaluronic acid-vitamin E succinate conjugates for improved lung cancer treatment

Background

Lung cancer is the primary cause of cancer-related death worldwide. A redox-sensitive nanocarrier system was developed for tumor-targeted drug delivery and sufficient drug release of the chemotherapeutic agent paclitaxel (PTX) for improved lung cancer treatment.

Methods

The redox-sensitive nanocarrier system constructed from a hyaluronic acid-disulfide-vitamin E succinate (HA-SS-VES, HSV) conjugate was synthesized and PTX was loaded in the delivery system. The physicochemical properties of the HSV nanoparticles were characterized. The redox-sensitivity, tumor-targeting and intracellular drug release capability of the HSV nanoparticles were evaluated. Furthermore, in vitro and in vivo antitumor activity of the PTX-loaded HSV nanoparticles was investigated in a CD44 over-expressed A549 tumor model.

Results

This HSV conjugate was successfully synthesized and self-assembled to form nanoparticles in aqueous condition with a low critical micelle concentration of 36.3 μg mL⁻¹. Free PTX was successfully entrapped into the HSV nanoparticles with a high drug loading of 33.5% (w/w) and an entrapment efficiency of 90.6%. Moreover, the redox-sensitivity of the HSV nanoparticles was confirmed by particle size change of the nanoparticles along with in vitro release profiles in different reducing environment. In addition, the HA-receptor mediated endocytosis and the potency of redox-sensitivity for intracellular drug delivery were further verified by flow cytometry and confocal laser scanning microscopic analysis. The antitumor activity results showed that compared to redox-insensitive nanoparticles and Taxol^®, PTX-loaded redox-sensitive nanoparticles exhibited much greater in vitro cytotoxicity and apoptosis-inducing ability against CD44 over-expressed A549 tumor cells. In vivo, the PTX-loaded HSV nanoparticles possessed much higher antitumor efficacy in an A549 mouse xenograft model and demonstrated improved safety profile. In summary, our PTX-loaded redox-sensitive HSV nanoparticles demonstrated enhanced antitumor efficacy and improved safety of PTX.

Conclusion

The results of our study indicated the redox-sensitive HSV nanoparticle was a promising nanocarrier for lung cancer therapy.

Water-Soluble Vitamin E-Tocopheryl Phosphate

The hydrophobicity of vitamin E poses transport and metabolic challenges to regulate its bioavailability and to prevent its accumulation in lipid-rich tissues such as adipose tissue, brain, and liver. Water-soluble precursors of vitamin E (α-tocopherol, αT), such as its esters with acetate (αTA), succinate (αTS), or phosphate (αTP), have increased solubility in water and stability against reaction with free radicals, but they are rapidly converted during their uptake into the lipid-soluble vitamin E. Therefore, the bioavailability of these precursors as intact molecules is low; nevertheless, at least for αTS and αTP, the recent research has revealed unique regulatory effects on signal transduction and gene expression and the modulation of cellular events ranging from proliferation, survival/apoptosis, lipid uptake and metabolism, phagocytosis, long term potentiation, cell migration, telomere maintenance, and angiogenesis. Moreover, water-soluble derivatives of vitamin E including some based on αTP are increasingly used as components of nanocarriers for enhanced and targeted delivery of drugs and other molecules (vitamins, including αT and αTP itself, vitamin D3, carnosine, caffeine, docosahexaenoic acid (DHA), insulin) and cofactors such as coenzyme Q10. In this review, the chemical characteristics, transport, metabolic pathways, and molecular mechanisms of action of αTP in cells and tissues are summarized and put into perspective with its possible role in the prevention of a number of diseases.

Reduction Responsive Nanovesicles Derived from Novel α-Tocopheryl-Lipoic Acid Conjugates for Efficacious Drug Delivery to Sensitive and Drug Resistant Cancer Cells

Two novel α-tocopheryl-lipoic acid conjugates (TL1 and TL2) were synthesized for the anticancer drug, doxorubicin (DOX), delivery. Both conjugates were able to form stable nanovesicles. The critical aggregation concentration (CAC) was determined using 4-(N,N-dimethylamino)cinnamaldehyde (DMACA) as a fluorescence probe. Formation of highly packed nanovesicles was characterized by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy and microviscosity measurements. The morphologies of nanovesicles were visualized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The response of nanovesicles to reducing environment of cells was probed by the addition of dithiothreitol (DTT), which was followed by the increase in the hydrodynamic diameter under dynamic light scattering (DLS) measurements. The encapsulation efficiency of a commonly used anticancer drug, doxorubicin (DOX), in nanovesicles was found to be ∼60% and ∼55% for TL1 and TL2, respectively (TL1-DOX and TL2-DOX). Also, the cumulative drug (DOX) release from DOX-encapsulated nanovesicles in response to biological reducing agent glutathione (GSH) was ∼50% and ∼40% for TL1-DOX and TL2-DOX, respectively, over a period of 10 h. Both TL1-DOX and TL2-DOX delivered the anticancer drug, doxorubicin (DOX), across the DOX-sensitive and DOX-resistant HeLa (HeLa-DOX^R) cells in an efficient manner and significantly more efficaciously than the drug alone treatments, especially in HeLa-DOX^R cells. The nanovesicle mediated DOX treatment also showed significantly higher cell death when compared to DOX alone treatment in HeLa-DOX^R cells. Blood compatibility of the nanovesicles was supported from clotting time, hemolysis, and red blood cell (RBC) aggregation experiments for their potential in vivo applications. Concisely, we present biocompatible and responsive nanovesicles for efficacious drug delivery to drug-sensitive and drug-resistant cancer cells.

Selective delivery of adapalene to the human hair follicle under finite dose conditions using polymeric micelle nanocarriers

Drug delivery systems that target the pilosebaceous unit (PSU) selectively could improve the clinical management of diseases that originate in the hair follicle. The aims of this study were (i) to prepare polymeric micelles using d-α-tocopheryl polyethylene glycol succinate diblock copolymer that incorporated adapalene (ADA), a retinoid indicated for Acne vulgaris, and (ii) to investigate the feasibility of delivering ADA preferentially to the PSU under finite dose conditions - thereby better approximating actual conditions of use by patients. Incorporation of ADA into spherical micelles (d_n <20 nm) increased aqueous solubility by ∼50 000-fold (from <4 ng mL^-1 to 0.2 mg mL^-1). Optimized micelle solution and gel formulations (0.02% ADA) were stable after storage for 4 weeks at 4 °C. Finite dose experiments using full-thickness porcine and human skin revealed that ADA delivery efficiency from micelle solution and gel formulations was equivalent and was >2- and 10-fold higher than that from Differin® gel and Differin® cream (products containing ADA at 0.1% (w/w)). Follicular delivery studies in human skin, using a punch biopsy technique to extract the intact PSU, demonstrated that the micelle solution and gel formulations did indeed enable preferential delivery of ADA to the PSU (4.5- and 3.3-fold higher, respectively, than that to PSU-free skin biopsies). Confocal laser scanning microscopy provided visual corroboration that ADA was uniformly distributed in the hair follicles. In conclusion, the results confirmed that polymeric micelle nanocarriers enabled selective, targeted drug delivery to the PSU under finite dose conditions and so might improve therapy of follicular diseases and decrease off-site side-effects.

Redox-responsive micelles from disulfide bond-bridged hyaluronic acid-tocopherol succinate for the treatment of melanoma

Nanotechnology-based chemotherapy is efficient in cancer treatment due to the targeted delivery of small molecules via nano-carriers, which are usually regarded as "inert". However, nano-materials are more preferred as carriers since many cause synergistic anti-tumor effects along with the drug cargo. In this study, a "bioactive" tocopherol succinate (TOS) was grafted to hyaluronic acid (HA) via of disulfide bonds to obtain HA-ss-TOS conjugates which can assemble into nano-micelles but dissociate when exposed to reducing environments in vitro and in vivo. Moreover, paclitaxel-loaded HA-ss-TOS micelles (HA-ss-TOS-PTX) can be efficiently taken up by B16F10 cells overexpressing CD 44, thereafter exhibiting enhanced cytotoxicity. The in vivo imaging study here revealed much greater tumor accumulation of Dir-labeled HA-ss-TOS compared to the free Dir group. In vivo antitumor activities further ensured that the PTX-loaded HA-ss-TOS micelles provided superior antineoplastic responses versus PTX-loaded HA-TOS micelles and Taxol. Moreover, the subcellular dissociated TOS from HA-ss-TOS showed synergistic effects with PTX. These experimental results revealed that reduction-responsive PTX-loaded polymeric nano-micelles with multi-functional properties hold great potential for anti-tumor treatment and, thus, should be further studied.

Synthetically lethal nanoparticles for treatment of endometrial cancer

Uterine serous carcinoma, one of the most aggressive types of endometrial cancer, is characterized by poor outcomes and mutations in the tumour suppressor p53. Our objective was to engender synthetic lethality to paclitaxel (PTX), the frontline treatment for endometrial cancer, in tumours with mutant p53 and enhance the therapeutic efficacy using polymeric nanoparticles (NPs). First, we identified the optimal NP formulation through comprehensive analyses of release profiles and cellular-uptake and cell viability studies. Not only were PTX-loaded NPs superior to PTX in solution, but the combination of PTX-loaded NPs with the antiangiogenic molecular inhibitor BIBF 1120 (BIBF) promoted synthetic lethality specifically in cells with the loss-of-function (LOF) p53 mutation. In a xenograft model of endometrial cancer, this combinatorial therapy resulted in a marked inhibition of tumour progression and extended survival. Together, our data provide compelling evidence for future studies of BIBF- and PTX-loaded NPs as a therapeutic opportunity for LOF p53 cancers.

Investigation of the intracellular oxidative stress amplification, safety and anti-tumor effect of a kind of novel redox-responsive micelle

Redox-responsive FSST micelles with good biocompatibility can increase ROS levels in tumor cells and amplify oxidative stress, ultimately inducing apoptosis.

pH-sensitive micelles with charge-reversible property for tumor growth inhibition and anti-metastasis

Biocompatible VE-based micelles with charge-reversible property for PTX delivery demonstrating effective antitumor and anti-metastasis effects.

pH-sensitive polymeric nanoparticles with antioxidant and anti-inflammatory properties against cisplatin-induced hearing loss

Polymeric nanoparticles (NPs) based on smart synthetic amphiphilic copolymers are used to transport and controlled release dexamethasone in the inner ear to protect against the ototoxic effect of cisplatin. The NPs were based on a mixture of two pseudo-block polymer drugs obtained by free radical polymerization: poly(VI-co-HEI) and poly(VP-co-MVE) or poly(VP-co-MTOS), being VI 1-vinylimidazole, VP N-vinylpyrrolidone, and HEI, MVE and MTOS the methacrylic derivatives of ibuprofen, α-tocopherol and α-tocopheryl succinate, respectively. The NPs were obtained by nanoprecipitation with appropriate hydrodynamic properties, and isoelectric points that matched the pH of inflamed tissue. The NPs were tested both in vitro (using HEI-OC1 cells) and in vivo (using a murine model) with good results. Although the concentration of dexamethasone administered in the NPs is around two orders of magnitude lower that the conventional treatment for intratympanic administration, the NPs protected from the cytotoxic effect of cisplatin when the combination of the appropriate properties in terms of size, zeta potential, encapsulation efficiency and isoelectric point were achieved. To the best of our knowledge this is the first time that pH sensitive NPs are used to protect from cisplatin-induced hearing loss by intratympanic administration.

Recent developments in d-α-tocopheryl polyethylene glycol-succinate-based nanomedicine for cancer therapy

Cancer remains an obstacle to be surmounted by humans. As an FDA-approved biocompatible drug excipient, d-α-tocopheryl polyethylene glycol succinate (TPGS) has been widely applied in drug delivery system (DDS). Along with in-depth analyses of TPGS-based DDS, increasingly attractive results have revealed that TPGS is able to act not only as a simple drug carrier but also as an assistant molecule with various bio-functions to improve anticancer efficacy. In this review, recent advances in TPGS-based DDS are summarized. TPGS can inhibit P-glycoprotein, enhance drug absorption, induce mitochondrial-associated apoptosis or other apoptotic pathways, promote drug penetration and tumor accumulation, and even inhibit tumor metastasis. As a result, many formulations, by using original TPGS, TPGS-drug conjugates or TPGS copolymers, were prepared, and as expected, an enhanced therapeutic effect was achieved in different tumor models, especially in multidrug resistant and metastatic tumors. Although the mechanisms by which TPGS participates in such functions are not yet very clear, considering its effectiveness in tumor treatment, TPGS-based DDS appears to be one of the best candidates for future clinical applications.

Nano-delivery system targeting to cancer stem cell cluster of differentiation biomarkers

Cancer stem cells (CSCs) are one of the most important origins of cancer progression and metastasis. CSCs have unique self-renewal properties and diverse cell membrane receptors that induced the resistance to the conventional chemotherapeutic agents. Therefore, the therapeutic removal of CSCs could result in the cancer cure with lack of recurrence and metastasis. In this regard, targeting CSCs in accordance to their specific biomarkers is a talented attitude in cancer therapy. Various CSCs surface biomarkers have been described, which some of them exhibited similarities on different cancer cell types, while the others are cancer specific and have just been reported on one or a few types of cancers. In this review, the importance of CSCs in cancer development and therapeutic response has been stated. Different CSCs cluster of differentiation (CD) biomarkers and their specific function and applications in the treatment of cancers have been discussed, Special attention has been made on targeted nano-delivery systems. In this regard, several examples have been illustrated concerning specific natural and artificial ligands against CSCs CD biomarkers that could be decorated on various nanoparticulated drug delivery systems to enhance therapeutic index of chemotherapeutic agents or anticancer gene therapy. The outlook of CSCs biomarkers discovery and therapeutic/diagnostic applications was discussed.

Multifunctional decoration of alpha-tocopheryl succinate-based NP for cancer treatment: effect of TPP and LTVSPWY peptide

Active targeting not only of a specific cell but also a specific organelle maximizes the therapeutic activity minimizing adverse side effects in healthy tissues. The present work describes the synthesis, characterization, and in vitro biological activity of active targeting nanoparticles (NP) for cancer therapy based on α-tocopheryl succinate (α-TOS), a well-known mitocan, that selectively induces apoptosis of cancer cells and proliferalting endothelial cells. Human epidermal growth factor receptor 2 (HER2) targeting peptide LTVSPWY (PEP) and triphenylphosphonium lipophilic cation (TPP) were conjugated to a previously optimized RAFT block copolymer that formed self-assembled NP of appropriate size for this application and low polydispersity by self-organized precipitation method. PEP and TPP were included in order to target not only HER2 positive cancer cells, but also the mitochondria of these cancer cells, respectively. The in vitro experiments demonstrated the faster incorporation of the active-targeting NP and the higher accumulation of TPP-bearing NP in the mitochondria of MDA-MB-453 HER2 positive cancer cells compared to non-decorated NP. Moreover, the encapsulation of additional α-TOS in the hydrophobic core of the NP was achieved with high efficiencies. The loaded NP presented higher cytotoxicity than unloaded NP but preserved their selectivity against cancer cells in a range of tested concentrations.

Recent advances in TPGS-based nanoparticles of docetaxel for improved chemotherapy

Docetaxel (DTX) is one of the important antitumor drugs, being used in several common chemotherapies to control leading cancer types. Severe toxicities of the DTX are prominent due to sudden parenteral exposure of desired loading dose to maintain the therapeutic concentration. Field of nanotechnology is leading to resist sudden systemic exposure of DTX with more specific delivery to the site of cancer. Further nanometric size range of the formulation aid for prolonged circulation, thereby extensive exposure results better efficacy. In this article, we extensively reviewed the therapeutic benefit of incorporating d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS, or simply TPGS) in the nanoparticle (NP) formulation of DTX for improved delivery, tumor control and tolerability. TPGS is well accepted nonionic-ampiphilic polymer which has been identified in the role of emulsifier, stabilizer, penetration enhancer, solubilizer and in protection in micelle. Simultaneously, P-glycoprotein inhibitory activity of TPGS in the multidrug resistant (MDR) cancer cells along with its apoptotic potential are the added advantage of TPGS to be incorporated in nano-chemotherapeutics. Thus, it could be concluded that TPGS based nanoparticulate application is an advanced approach to improve therapeutic efficacy of chemotherapeutic agents by better internalization and sustained retention of the NPs.

Synergistic apoptotic effects of apigenin TPGS liposomes and tyroservatide: implications for effective treatment of lung cancer

To develop an alternative treatment for lung cancer, a combination of two potent chemotherapeutic agents – liposomal apigenin and tyroservatide – was developed. The therapeutic potential of this combination was investigated using A549 cells. Apigenin and tocopherol derivative-containing D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) liposomes might improve the delivery of apigenin to tumor cells, both in vitro and in vivo. Importantly, compared to either agent alone, the combination of apigenin TPGS liposomes and tyroservatide exhibited superior cytotoxicity, induced stronger G2 arrest, and suppressed A549 cancer cell invasion at a lower dose. The proapoptotic synergistic effects were also observed in A549 cells using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, flow cytometry, and Western blot analysis. More importantly, in vivo results showed that the combination of apigenin TPGS liposomes and tyroservatide exhibited tumor-growth inhibitory effects in A549 cell-bearing mice. In conclusion, our study showed that this combination therapy could serve as a promising synergistic therapeutic approach to improve outcomes in patients with lung cancer.

A pH sensitive polymeric micelle for co-delivery of doxorubicin and α-TOS for colon cancer therapy

Combination therapy through simultaneous delivery of two or more therapeutic agents using nanocarriers has emerged as an advanced tactic for cancer treatment. To ensure that two therapeutic agents can be co-delivered and rapidly release their cargo in tumor cells, a biocompatible pH-sensitive copolymer, methoxy poly(ethylene glycol)-b-poly(hydroxypropyl methacrylamide-g-α-tocopheryl succinate-g-histidine) (abbreviated as PTH), was designed and synthesized. The PTH copolymers spontaneously self-assembled into micellar-type nanoparticles in aqueous solutions and are used for co-delivery of therapeutic agents, doxorubicin (Dox) and α-TOS. During micellization, π-π stacking occurred between Dox/α-TOS and imidazole rings of PTH copolymers inducing a regular and tight arrangement of copolymers and drugs to form rod-like micelles, thus efficiently increasing the drug loading and encapsulation efficiency. The micelles enabled the rapid release of both Dox and α-TOS when the pH decreased from 7.4 to 4.5. The protein adsorption assay revealed that low amounts of IgG and BSA were adsorbed on the micelles. In vivo biodistribution demonstrated that the micelles could largely accumulate in the tumor tissues. Furthermore, drug-loaded micelles treated with HCT116 cancer cells exhibited higher cytotoxicity than normal cells, which confirmed that α-TOS exhibited a synergy effect with Dox towards cancer cells, while no recognizable side effects were observed during the treatment from organ function tests.

Specifically Increased Paclitaxel Release in Tumor and Synergetic Therapy by a Hyaluronic Acid-Tocopherol Nanomicelle

Recently, interest in tumor-targeted and site-specific drug release from nanoparticles as a means of drug delivery has increased. In this study, we report a smart nanosized micelle formed by hyaluronic acid (HA) conjugated with d-α-tocopherol succinate (TOS) using a disulfide bond as the linker (HA-SS-TOS, HSST). HSST micelles can specifically bind to the CD44 receptors that are overexpressed by cancer cells. The high levels of glutathione (GSH) in tumor cells selectively break the disulfide bond linker. This effect results in the synchronous release of the payload and a TOS fragment. These two components subsequently demonstrate synergetic anticancer activity. First, we demonstrate that drug release from HSST occurs rapidly in physiological high redox conditions and inside cancer cells. Significant GSH-triggered drug release was also observed in vivo. Furthermore, an in vivo biodistribution study indicated that the HSST micelles efficiently accumulated at the tumor sites, primarily due to an enhanced permeability and retention effect and the efficient binding to the cancer cells that overexpressed the CD44 receptor. Interestingly, the synchronous release of paclitaxel (PTX) and the TOS fragment from the PTX-loaded HSST caused synergetic tumor cell killing and tumor growth inhibition. Our work presents a useful candidate for a drug delivery system that can specifically accumulate at tumor tissue, selectively release its payload and a TOS fragment, and thus display a synergetic anticancer effect.

Reversal of paclitaxel resistance in human ovarian cancer cells with redox-responsive micelles consisting of α-tocopheryl succinate-based polyphosphoester copolymers

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) is a major obstacle in achieving the therapeutic benefits of paclitaxel (PTX) in the treatment of human ovarian carcinoma. This study is aimed to develop an efficient PTX drug delivery approach to overcome MDR. Redox-responsive micelles consisting of amphiphilic polymers containing disulfide linkages, ie, poly (phosphate ester)-SS-D-α-tocopheryl succinate (POPEA-SS-TOS, PSST) were prepared. PTX-loaded PSST micelles (PTX/PSST-M) designed to display synergistic functions, including reversible inhibition of P-gp, intracellular redox-sensitive release and potent anticancer activities. The average size of PTX/PSST-M was 68.1±4.9 nm. The encapsulated PTX was released quickly through redox-triggered dissociation of micelles. The inhibition of P-gp activity and enhanced cellular accumulation of the PSST micelles were validated. PTX/PSST-M showed significantly increased cytotoxicity against PTX-resistant human ovarian cancer A2780/PTX cells: when the cells were treated with PTX/PSST-M for 48 h, the equivalent IC₅₀ value of PTX was reduced from 61.51 to 0.49 μmol/L. The enhanced cytotoxic effects of PTX/PSST-M against A2780/PTX cells were attributed to their synergistic effects on reducing the mitochondrial transmembrane potential, ATP depletion, ROS production, and activation of apoptotic pathways. Furthermore, PTX/PSST-M significantly increased cell apoptosis/necrosis and cell cycle arrest at the G₂/M phase in A2780/PTX cells. These results demonstrate that the redox-responsive PSST micelles inhibit P-gp activity and have a good potential to effectively reverse PTX resistance in human ovarian carcinoma cells by activating intrinsic apoptotic pathways.

Enhanced effect of folated pluronic F87-PLA/TPGS mixed micelles on targeted delivery of paclitaxel

Targeted drug delivery systems have great potential to overcome the side effect and improve the bioavailability of conventional anticancer drugs. In order to further improve the antitumor efficacy of paclitaxel (PTX) loaded in folated Pluronic F87/poly(lactic acid) (FA-F87-PLA) micelles, D-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS or Vitamin E TPGS) were added into FA-F87-PLA to form FA-F87-PLA/TPGS mixed micelles. The LE of PTX-loaded mixed micelles (13.5%) was highest in the mass ratio 5 to 3 of FA-F87-PLA to TPGS. The in vitro cytotoxicity assays indicated that the IC50 values for free PTX injections, PTX-loaded FA-F87-PLA micelles and PTX-loaded FA-F87-PLA/TPGS mixed micelles after 72h of incubation were 1.52, 0.42 and 0.037mg/L, respectively. The quantitative cellular uptake of coumarin 6-loaded FA-F87-PLA/TPGS and FA-F87-PLA micelles showed that the cellular uptake efficiency of mixed micelles was higher for 2 and 4h incubation, respectively. In vivo pharmacokinetic studies found that the AUC of PTX-loaded FA-F87-PLA/TPGS mixed micelles is almost 1.4 times of that of PTX-loaded FA-F87-PLA micelles. The decreased particle size and inhibition of P-glycoprotein effect induced by the addition of TPGS could result in enhancing the cellular uptake and improving the antitumor efficiency of PTX-loaded FA-F87-PLA/TPGS mixed micelles.

P-gp Inhibition and Mitochondrial Impairment by Dual-Functional Nanostructure Based on Vitamin E Derivatives To Overcome Multidrug Resistance

Vitamin E derivatives possess many essential features for drug-delivery applications, such as biocompatibility, stability, improvement of water solubility of hydrophobic compounds, anticancer activity, and the ability to overcome multidrug resistance (MDR). Herein, vitamin E derivatives are used to overcome MDR through a combined P-glycoprotein (P-gp) inhibition and mitochondrial impairment strategy. A novel nanomicellar drug-delivery system as a carrier for doxorubicin (DOX) was developed, in which d-α-tocopheryl polyethylene glycol 1000 succinate was used as a P-gp inhibitor, α-tocopheryl succinate was introduced as a mitochondrial disrupting agent, and d-α-tocopheryl polyethylene glycol 2000 succinate was used as the main building block of micelles. The optimal ratio between the components of the nanocarrier was determined. The resultant DOX-loaded mixed micelles exhibited a suitable size of 52.08 nm, high drug-loading encapsulation efficiency (>98%), high stability, and pH-dependent drug release. In vitro experiments demonstrated a significantly increased cytotoxic activity of DOX-loaded mixed micelles against resistant MCF-7/Adr cells (45-fold higher than DOX after 48 h of treatment). In vivo studies revealed superior antitumor efficiency with less cardio- and hepatotoxicities of DOX-loaded micelles compared with that of free DOX. These results highlight that the developed DOX-loaded mixed micelles have a promising potential to overcome MDR in chemotherapy for clinical usage.

d-α-Tocopheryl Succinate/Phosphatidyl Ethanolamine Conjugated Amphiphilic Polymer-Based Nanomicellar System for the Efficient Delivery of Curcumin and To Overcome Multiple Drug Resistance in Cancer

Nanomedicines have emerged as a promising treatment strategy for cancer. Multiple drug resistance due to overexpression of various drug efflux transporters and upregulation of apoptotic inhibitory pathways in cancer cells are major barriers that limit the success of chemotherapy. Here, we developed a d-α-tocopherol (α-TOS)/lipid-based copolymeric nanomicellar system (VPM) by conjugating phosphatidyl ethanolamine (PE) and α-TOS with poly(ethylene glycol) (PEG) via an amino acid linkage. The synthesized polymers were characterized by Fourier transform IR, gas-phase chromatography, and ¹H and ¹³C NMR spectroscopy. VPM exhibited mean hydrodynamic diameter of 141.0 ± 0.94 nm with low critical micelles concentrations (CMC) of 15 μM compared to plain PEG-PE micelles (PPM) with size of 23.9 ± 0.34 nm and CMC 20 μM. The bigger hydrophobic compartment in VPM resulted in improved loading of a potent chemotherapeutic drug, curcumin (Cur), and increased encapsulation efficiency (EE) (% drug loading 98.3 ± 1.92, and 85.3 ± 3.29; EE 14.8 ± 0.16 and 12.8 ± 0.09 for VPM and PPM, respectively). Curcumin loaded Vitamin E based micelles exhibited higher cytotoxicity compared to Curcumin loaded PEG-PE micelles in tested cancer cell lines. C-VPM demonstrated ∼3.2 and ∼2.7-fold higher ability to reverse multiple drug resistance compared to PPM and verapamil (concentration used 30 μM), respectively. In the in vivo study by using B16F10 implanted C57Bl6/J mice, C-VPM reduced the tumor volume and weight more efficiently than C-PPM by inducing apoptosis as analyzed by TUNEL assay on tumor cryosections. The newly developed polymeric micelles, VPM with improved drug loadability and ability to reverse the drug resistance could successfully be utilized as a nanocarrier system for hydrophobic chemotherapeutic agents for the treatment of drug-resistant solid tumors.

Structural and Spectroscopic Characterization of TPGS Micelles: Disruptive Role of Cyclodextrins and Kinetic Pathways

The aggregation and structure of d-α-tocopheryl polyethylene glycol succinate micelles, TPGS-1000, an amphiphilic derivative of vitamin E, were characterized using scattering and spectroscopic methods, and the impact of different cyclodextrins (CDs) on the self-assembly was investigated, with the view of combining these two versatile pharmaceutical excipients in drug formulations. Combined small-angle neutron scattering (SANS), dynamic light scattering, and time-resolved and steady-state fluorescence emission experiments revealed a core-shell architecture with a high aggregation number (N_agg ≈ 100) and a highly hydrated poly(ethylene oxide) corona (∼11 molecules of solvent per ethylene oxide unit). Micelles form gradually, with no sharp onset. Structural parameters and hydration of the aggregates were surprisingly stable with both temperature and concentration, which is a critical advantage for their use in pharmaceutical formulations. CDs were shown to affect the self-assembly of TPGS in different ways. Whereas native CDs induced the precipitation of a solid complex (pseudopolyrotaxane), methylated β-CDs led to different outcomes: constructive (micellar expansion), destructive (micellar rupture), or no effect, depending on the number of substituents and whether the substitution pattern was regular or random on the rims of the macrocycle. Time-resolved SANS studies on mixtures of TPGS with regularly dimethylated β-CD (DIMEB), which ruptures the micelles, revealed an almost instantaneous demicellization (<100 ms) and showed that the process involved the formation of large aggregates whose size evolved over time. Micellar rupture is caused by the formation of a TPGS-DIMEB inclusion complex, involving the incorporation of up to three macrocycles on the tocopherol, as shown by proton nuclear magnetic resonance (NMR) and ROESY NMR. Analysis of NMR data using Hill's equation revealed that the binding is rather cooperative, with the threading of the CD favoring the subsequent inclusion of additional CDs on the aliphatic moiety.

Development of nanoformulation approaches for the control of weeds

The nanoformulation of pesticides has the potential to increase food productivity, while resolving the drawbacks of conventional agrochemicals, which have negative environmental impacts. In this study, herbicide (metsulfuron methyl)-loaded pectin (polysaccharide) nanoparticles were synthesized and evaluated for herbicidal activity and cytotoxicity. The optimum formulation of nanoparticles was obtained using the Central Composite Design. The basic properties (mean particle size, stability, morphology, and interaction between polymer and herbicide) were characterized using a particle size analyzer (PSA), zeta potential, transmission electron microscopy (TEM), and Fourier Transform infrared spectroscopy (FTIR), respectively. The nanoparticles were found to be in size range of 50-90nm with zeta potential value of -35.9mV. The herbicide loading and herbicide encapsulation efficiency of the nanoparticles were determined to be 6.30% and 63±2%, respectively. The cytotoxicity of the herbicide-loaded nanoparticles was evaluated using healthy cell lines (Vero cell lines) and compared with that of commercial herbicide. In addition, an in-field evaluation of our nanoformulation's effects on the Chenopodium album plant was performed using a pectin nanocarrier. The results showed that application of herbicide-loaded nanoparticles could be used to reduce the use of herbicides with improved efficacy and environmental safety.

Lactobionic acid-conjugated TPGS nanoparticles for enhancing therapeutic efficacy of etoposide against hepatocellular carcinoma

Many effective anti-cancer drugs have limited use in hepatocellular carcinoma (HCC) therapy due to the drug resistance mechanisms in liver cells. In recent years, tumor-targeted drug delivery and the inhibition of drug-resistance-related mechanisms has become an integrated strategy for effectively combating chemo-resistant cancer. Herein, lactobionic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS-LA conjugate) has been developed as a potential asialoglycoprotein receptor (ASGPR)-targeted nanocarrier and an efficient inhibitor of P-glycoprotein (P-gp) to enhance etoposide (ETO) efficacy against HCC. The main properties of ETO-loaded TPGS-LA nanoparticles (NPs) were tested through in vitro and in vivo studies after being prepared using the nanoprecipitation method and characterized by dynamic light scattering (DLS). According to the results, smaller (∼141.43 nm), positively charged ETO-loaded TPGS-LA NPs were more suitable for providing efficient delivery to hepatoma cells by avoiding the clearance mechanisms. It was found that ETO-loaded TPGS-LA NPs were noticeably able to enhance the cytotoxicity of ETO in HepG2 cells. Besides this, markedly higher internalization by the ASGPR-overexpressed HepG2 cells and efficient accumulation at the tumor site in vivo were revealed in the TPGS-LA NP group. More importantly, animal studies confirmed that ETO-loaded TPGS-LA NPs achieved the highest therapeutic efficacy against HCC. Interestingly, ETO-loaded TPGS-LA NPs also exhibited a great inhibitory effect on P-gp compared to the ETO-loaded TPGS NPs. These results suggest that TPGS-LA NPs could be used as a potential ETO delivery system against HCC.

Novel dual VES phospholipid self-assembled liposomes with an extremely high drug loading efficiency

Vitamin E succinate (VES), a unique selective anti-cancer drug, has attracted much attention for its ability to induce apoptosis in various cancer cells. Importantly, it has been reported that VES is largely non-toxic to normal cells. However, poor aqueous solubility and bioavailability extensively restricted its clinical utility. In this report, dual VES phospholipid conjugate (di-VES-GPC) prodrug based liposomes were prepared in order to develop an efficient delivery system for VES. Di-VES-GPC was first synthesized by conjugating VES with l-α-glycerophosphorylcholine (GPC) using N,N'-dicyclohexylcarbodiimide (DCC) as a coupling agent. The di-VES-GPC prodrug was able to self-assemble into liposomes by reverse-phase evaporation method. The structure of the liposomes was characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and cryo-TEM. The results showed that di-VES-GPC assembled liposomes were spherical with an average diameter approximately 183nm. Cryo-TEM data confirmed the formation of multilamellar liposomes with the bilayer thickness about 5nm by the assembly of the conjugate without any excipient. The VES drug loading highly reaches up to 82.8wt% in the liposomes after a simple calculation. Furthermore, the in vitro release behavior of di-VES-GPC liposomes was evaluated in different media. It was found that the liposomes could release free VES at a weakly acidic microenvironment but exhibited good stability under a simulated biological condition. The cellular uptake and intracellular drug release tests demonstrated that di-VES-GPC liposomes could be internalized effectively and converted into parent drug VES in cancer cells. Furthermore, in vitro antitumor activities of the di-VES-GPC liposomes were evaluated by MTT assay and flow cytometry. It was revealed that the liposomes presented comparable cytotoxicities to free VES. Taken together, the di-VES-GPC liposomes might provide an excellent formulation of VES which have potential in the treatment of cancers.

Transcription activator, hyaluronic acid and tocopheryl succinate multi-functionalized novel lipid carriers encapsulating etoposide for lymphoma therapy

Delivery of chemotherapeutic drugs using nanocarriers is emerging as a promising approach for the treatment of cancer. The aim of this research was to develop a dual targeted d-α-tocopheryl succinate (TOS) functionalized nanostructured lipid carriers (NLCs), using etoposide (ETP) as a model drug to prove their in vitro and in vivo anti-tumor effects. Novel ETP loaded NLCs were constructed (ETP-NLCs). Hyaluronic acid (HA) and cell-penetrating peptide transcription activator (TAT) was applied for the surface decoration of ETP NLCs (HATOS/TATTOS-ETP-NLCs). The antitumor efficiency of HATOS/TATTOS-ETP-NLCs was evaluated in tumor bearing animal models. HATOS/TATTOS-ETP-NLCs displayed significantly higher transfection efficiency and better antitumor ability than undecorated ETP-NLCs in lymphoma cells bearing mice model. The newly constructed NLCs could successfully load drug and gene; and TAT could function as excellent targeting ligands to improve the cell targeting ability of the gene loaded nanocarriers. The resulting dual ligands decorated vectors could be a promising targeted gene delivery system for the lymphoma treatment.

Redox-sensitive self-assembled nanoparticles based on alpha-tocopherol succinate-modified heparin for intracellular delivery of paclitaxel

To remedy the problems riddled in cancer chemotherapy, such as poor solubility, low selectivity, and insufficient intra-cellular release of drugs, novel heparin-based redox-sensitive polymeric nanoparticles were developed. The amphiphilic polymer, heparin-alpha-tocopherol succinate (Hep-cys-TOS) was synthesized by grafting hydrophobic TOS to heparin using cystamine as the redox-sensitive linker, which could self-assemble into nanoparticles in phosphate buffer saline (PBS) with low critical aggregation concentration (CAC) values ranging from 0.026 to 0.093mg/mL. Paclitaxel (PTX)-loaded Hep-cys-TOS nanoparticles were prepared via a dialysis method, exhibiting a high drug-loading efficiency of 18.99%. Physicochemical properties of the optimized formulation were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM) and differential scanning calorimetry (DSC). Subsequently, the redox-sensitivity of Hep-cys-TOS nanoparticles was confirmed by the changes in size distribution, morphology and appearance after dithiothreitol (DTT) treatment. Besides, the in vitro release of PTX from Hep-cys-TOS nanoparticles also exhibited a redox-triggered profile. Also, the uptake behavior and pathways of coumarin 6-loaded Hep-cys-TOS nanoparticles were investigated, suggesting the nanoparticles could be taken into MCF-7 cells in energy-dependent, caveolae-mediated and cholesterol-dependent endocytosis manners. Later, MTT assays of different PTX-free and PTX-loaded formulations revealed the desirable safety of PTX-free nanoparticles and the enhanced anti-cancer activity of PTX-loaded Hep-cys-TOS nanoparticles (IC₅₀=0.79μg/mL). Apoptosis study indicated the redox-sensitive formulation could induce more apoptosis of MCF-7 cells than insensitive one (55.2% vs. 41.7%), showing the importance of intracellular burst release of PTX. Subsequently, the hemolytic toxicity confirmed the safety of the nanoparticles for intravenous administration. The results indicated the developed redox-sensitive nanoparticles were promising as intracellular drug delivery vehicles for cancer treatment.

D-α-tocopheryl polyethylene glycol 1000 succinate functionalized nanographene oxide for cancer therapy

AIM

To evaluate the therapeutic capacity of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-functionalized nanographene oxide (nGO) in breast cancer cells.

METHODS

TPGS-functionalized nGO-based materials were obtained through two different approaches: a simple sonication method and a one-pot hydrothermal treatment.

RESULTS

TPGS coating successfully improved the stability of the nGO-based materials. The nanomaterials that underwent the hydrothermal procedure generated a 1.4- to 1.6-fold higher temperature variation under near infrared laser irradiation than those prepared only by sonication. In vitro, the TPGS/nGO derivatives reduced breast cancer cells' viability and had an insignificant effect on healthy cells. Furthermore, the combined application of TPGS/nGO derivatives and near infrared light generated an improved therapeutic effect.

CONCLUSION

TPGS/nGO derivatives are promising materials for breast cancer phototherapy.

Robust, Responsive, and Targeted PLGA Anticancer Nanomedicines by Combination of Reductively Cleavable Surfactant and Covalent Hyaluronic Acid Coating

PLGA-based nanomedicines have enormous potential for targeted cancer therapy. To boost their stability, targetability, and intracellular drug release, here we developed novel multifunctional PLGA anticancer nanomedicines by combining a reductively cleavable surfactant (RCS), vitamin E-SS-oligo(methyl diglycol l-glutamate), with covalent hyaluronic acid (HA) coating. Reduction-sensitive HA-coated PLGA nanoparticles (rHPNPs) were obtained with small sizes of 55-61 nm and ζ potentials of -26.7 to -28.8 mV at 18.4-40.3 wt % RSC. rHPNPs were stable against dilution and 10% FBS while destabilized under reductive condition. The release studies revealed significantly accelerated docetaxel (DTX) release in the presence of 10 mM glutathione. DTX-rHPNPs exhibited potent and specific antitumor effect to CD44 + A549 lung cancer cells (IC₅₀ = 0.52 μg DTX equiv/mL). The in vivo studies demonstrated that DTX-rHPNPs had an extended circulation time and greatly enhanced tolerance in mice. Strikingly, DTX-rHPNPs completely inhibited growth of orthotopic human A549-Luc lung tumor in mice, leading to a significantly improved survival rate and reduced adverse effect as compared to free DTX. This study highlights that advanced nanomedicines can be rationally designed by combining functional surfactants and surface coating.

Synthesis, characterization, and in-vitro antitumor activity of the polyethylene glycol (350 and 1000) succinate derivatives of the tocopherol and tocotrienol isomers of Vitamin E

Vitamin E refers to a group of saturated tocopherol (T) isomers and the biologically more active unsaturated tocotrienol (T₃) isomers. PEGylated α-tocopherol, commercially known as Vitamin E TPGS, has been used as an emulsifier and therapeutic agent for children with vitamin E deficiency. Limited information, however, is available about the PEG conjugates of the tocotrienol isomers of vitamin E. The current work was therefore undertaken to synthesize and characterize the water soluble polyethylene glycol (PEG 350 and 1000) derivatives of T and T₃. Yield and the identity of the synthesized products were confirmed by ¹H NMR, mass spectroscopy, HPLC, and thermal analysis. The self-assembly of the PEGylated vitamin E isomers in water at critical micelle concentrations (CMC) was further confirmed by size, zeta, and Cryo-TEM image analysis. While stable at pH 7.4, PEG conjugates were found to rapidly hydrolyze at pH 1.2. Our data showed that PEGylated T₃ isomers were significantly more active as inhibitors for P-glycoprotein than PEGylated T. The in vitro cytotoxicity of the conjugates was also tested against a large panel of normal and tumorigenic cells. Of the conjugates, γ-T₃PGS 1000 and δ-T₃PGS 1000 were found to have the least toxicity against non-tumorigenic breast and pancreatic cell lines, which may be advantageous for its use as functional excipients in drug delivery. The results from the current work have demonstrated the feasibility of synthesizing PEGylated conjugates of vitamin E isomers and highlighted the potential use of these conjugates in drug delivery as functional and safer excipients especially for γ-T₃PGS 1000 and δ-T₃PGS 1000 conjugate.

Ascorbyl palmitate/d-α-tocopheryl polyethylene glycol 1000 succinate monoester mixed micelles for prolonged circulation and targeted delivery of compound K for antilung cancer therapy in vitro and in vivo

The roles of ginsenoside compound K (CK) in inhibiting tumor have been widely recognized in recent years. However, low water solubility and significant P-gp efflux have restricted its application. In this study, CK ascorbyl palmitate (AP)/d-α-tocopheryl polyethylene glycol 1000 succinate monoester (TPGS) mixed micelles were prepared as a delivery system to increase the absorption and targeted antitumor effect of CK. Consequently, the solubility of CK increased from 35.2±4.3 to 1,463.2±153.3 μg/mL. Furthermore, in an in vitro A549 cell model, CK AP/TPGS mixed micelles significantly inhibited cell growth, induced G0/G1 phase cell cycle arrest, induced cell apoptosis, and inhibited cell migration compared to free CK, all indicating that the developed micellar delivery system could increase the antitumor effect of CK in vitro. Both in vitro cellular fluorescence uptake and in vivo near-infrared imaging studies indicated that AP/TPGS mixed micelles can promote cellular uptake and enhance tumor targeting. Moreover, studies in the A549 lung cancer xenograft mouse model showed that CK AP/TPGS mixed micelles are an efficient tumor-targeted drug delivery system with an effective antitumor effect. Western blot analysis further confirmed that the marked antitumor effect in vivo could likely be due to apoptosis promotion and P-gp efflux inhibition. Therefore, these findings suggest that the AP/TPGS mixed micellar delivery system could be an efficient delivery strategy for enhanced tumor targeting and antitumor effects.

IR780-loaded TPGS-TOS micelles for breast cancer photodynamic therapy

IR780 iodide is a near-infrared (NIR) dye with a huge potential for cancer imaging and phototherapy. However, its biomedical application is strongly impaired by its lipophilic character. Herein, amphiphilic micelles based on d-α-tocopheryl polyethylene glycol succinate (TPGS) and d-α-tocopheryl succinate (TOS), two vitamin E derivatives with intrinsic anticancer activity, are explored to load IR780. IR780-loaded micelles with suitable sizes are obtained by using specific TPGS and TOS weight feed ratios during micelles formulation and these are able to encapsulate IR780 with high efficiency. In in vitro assays, the IR780-loaded micelles induce a cytotoxic effect in cancer cells upon exposure to NIR irradiation through the generation of reactive oxygen species (photodynamic therapy). This effective ablation of cancer cells is achieved using an ultra-low IR780 concentration. Moreover, IR780-loaded micelles also have the ability to act as photothermal and imaging agents, which widens their therapeutic and diagnostic potential. Overall, TPGS-TOS micelles are promising nanoplatforms for IR780-mediated cancer phototherapy and imaging.

Loading docetaxel in β-cyclodextrin-based micelles for enhanced oral chemotherapy through inhibition of P-glycoprotein mediated efflux transport

β-Cyclodextrin-based polymeric micelle (PELC) effectively delivered docetaxel by oral administration through inhibition of P-glycoprotein mediated efflux.

Polymer-Based Materials in Cancer Treatment: From Therapeutic Carrier and Ultrasound Contrast Agent to Theranostic Applications

The emergence of theranostics with ultrasound technology is a promising development, as it opens pathways to providing more effective treatments for cancer. Advancements in ultrasound imaging would give a more detailed and accurate image for better diagnosis and treatment planning. Polymeric ultrasound contrast agents (UCAs) are appealing because they are stable and easily modified for active targeting. In addition, a better therapy could be achieved in conjunction with advancements in UCAs. The active targeting not only makes the precise imaging possible, but also leads to targeted delivery of active components to specific local treatment sites. A polymeric nanocarrier with surface bioconjugation is the key to prolonging the bioavailability of the encapsulated drugs or genes and the capacity to target the specific tumor site. Using ultrasound with other imaging modalities will open more precise and better ways for diagnosis and therapy and bring us a step closer to personalized medicine. This review focuses on polymer-based materials of UCAs, multimodal imaging agents and therapeutic carriers that have been currently explored for their theranostic applications involving ultrasound for cancer diagnosis and treatment.