Paclitaxel-Loaded Poly(n-butylcyanoacrylate) Nanoparticle Delivery System to Overcome Multidrug Resistance in Ovarian Cancer

Analyzing the Mechanical Properties of Free-Standing PACA Thin Films Using Microindentation Technique

Assessing the mechanical properties of materials is of fundamental relevance for their rational usage, but can be challenging with standard tensile testing for highly brittle polymers used, e.g., as coatings. Here, a procedure for the mechanical analysis of free-standing poly(alkyl cyanoacrylate) (PACA) films using microindentation has been explored. Rigid and transparent films from PACA with various side chain compositions were formed on top of square polymer frames by in situ polymerization. Under microscopic control, the free-standing films were analyzed using a microelectromechanical sensing system. By this procedure, decreasing Young's moduli E for increasing PACA side chain length and flexibility were determined with strain at break ε_B between 0.36% for poly(ethyl cyanoacrylate) and 4.6% for poly(methoxyethyl cyanoacrylate). Based on this successful application, the applied methodology may be relevant for characterizing various coating materials, which are otherwise hard to form as thin free-standing films, and using the data, e.g., in computationally assisted design and evaluation of hybrid material devices.

Design, Preparation, and Evaluation of Osthol Poly-Butyl-Cyanoacrylate Nanoparticles with Improved In Vitro Anticancer Activity in Neuroblastoma Treatment

Osthol (osthole), known as a neuroprotective drug, has shown potent anticancer activity. However, the potential clinical application of osthol is limited due to its low water solubility and low bioavailability. Polybutyl cyanoacrylate (PBCA) has been widely used to improve the solubility of drugs with poor water solubility. In this study, an orthogonal experimental design (OED) was applied to design the preparation process of PBCA nanoparticles (NPs). Then, nanoparticles were prepared and evaluated in terms of physicochemical properties, in vitro release, and cellular uptake, etc. Further, the anti-cancer activity of osthol-PBCA NPs was demonstrated in SH-SY5Y cells. The pharmacokinetics and area under the curve (AUC) were investigated. The obtained osthol-NPs presented a spherical shape with a particle size of 110 ± 6.7 nm, a polydispersity index (PDI) of 0.126, and a zeta potential of −13 ± 0.32 mV. Compared with the free osthol, the drugs in osthol-NPs presented better stability and sustained release pattern activity. In vitro analysis using SH-SY5Y neuroblastoma cells showed that osthol-loaded nanoparticles displayed a significantly enhanced intracellular absorption process (three times) and cytotoxicity compared with free osthol (p < 0.05, increased 10−20%). The in vivo pharmacokinetic study revealed that the AUC of osthol-NPs was 3.3-fold higher than that of free osthol. In conclusion, osthol-PBCA NPs can enhance the bioactivity of osthol, being proposed as a novel, promising vehicle for drug delivery.

A new core–shell-type nanoparticle loaded with paclitaxel/norcantharidin and modified with APRPG enhances anti-tumor effects in hepatocellular carcinoma

Nanoparticle delivery systems have been shown to improve the therapeutic efficacy of anti-cancer drugs, including a variety of drugs for the treatment of hepatocellular carcinoma (HCC). However, the current systems show some limitations, and the delivery of more effective nanoparticle systems for anti-HCC drugs with better targeting ability are needed. Here, we created paclitaxel (PTX)/norcantharidin (NCTD)-loaded core–shell lipid nanoparticles modified with a tumor neovasculature-targeted peptide (Ala-Pro-Arg-Pro-Gly, APRPG) and investigated their anti-tumor effects in HCC. Core–shell-type lipid nanoparticles (PTX/NCTD-APRPG-NPs) were established by combining poly(lactic-co-glycolic acid) (PLGA)-wrapped PTX with phospholipid-wrapped NCTD, followed by modification with APRPG. For comparison, PTX-loaded PLGA nanoparticles (PTX-NPs) and PTX/NCTD-loaded core–shell-type nanoparticles without APRPG (PTX/NCTD-NPs) were prepared. The in vitro and in vivo anti-tumor effects were examined in HepG2 cells and tumor-bearing mice, respectively. Morphological and release characterization showed that PTX/NCTD-APRPG-NPs were prepared successfully and achieved up to 90% release of PTX in a sustained manner. Compared with PTX/NCTD-NPs, PTX/NCTD-APRPG-NPs significantly enhanced the uptake of PTX. Notably, the inhibition of proliferation and migration of hepatoma cells was significantly higher in the PTX/NCTD-APRPG-NP group than those in the PTX-NP and PTX/NCTD-NP groups, which reflected significantly greater anti-tumor properties as well. Furthermore, key molecules in cell proliferation and apoptosis signaling pathways were altered most in the PTX/NCTD-APRPG-NP group, compared with the PTX-NP and PTX/NCTD-NP groups. Collectively, PTX/NCTD-loaded core–shell lipid nanoparticles modified with APRPG enhance the effectiveness of anti-HCC drugs and may be an effective system for the delivery of anti-HCC drugs.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

Recent Advancements in Nanotechnology for Oral Cancer: a Review

Background:

Oral cancer is the life threatening disease causing mortality. The majority of chemotherapeutic anticancer agents are toxic to healthy tissues, have poor bioavailability and affect the quality of life of the patients.

Objective:

The main challenge in the treatment of oral cancer is the effective and safe delivery of chemotherapeutic anticancer drugs. This present review deals with the recent advancement in the nanotechnologies and its probable applications in the oral cancer treatment.

Methods:

This review includes a gist of suitable literature.

Results:

Nanotechnology brings novel methodologies or modifications in current anticancer therapies to improve individual wellbeing and survival.

Conclusion:

Nanotechnology put forward the potential of increasing the efficacy of the therapy and targeted drug delivery, which in turn increase drug absorption and bioavailability at the site of tumour. Different nanocarriers include liposomes, polymeric nanoparticles, inorganic nanoparticles, combinational (polymeric- inorganic) nanoparticles, magnetic nanoparticles, nanolipids, hydrogels, dendrimers and polymeric micelles. This review confers development of new drug delivery approaches for effective therapeutic outcomes and abating the toxicity to healthy tissues.

Role of non-coding RNAs in modulating the response of cancer cells to paclitaxel treatment

Paclitaxel is a chemotherapeutic substance that is administered for treatment of an extensive spectrum of human malignancies. In spite of its potent short-term effects against tumor cells, resistance to paclitaxel occurs in a number of patients precluding its long-term application in these patients. Non-coding RNAs have been shown to influence response of cancer cells to this chemotherapeutic agent via different mechanisms. Mechanistically, these transcripts regulate expression of several genes particularly those being involved in the apoptotic processes. Lots of in vivo and in vitro assays have demonstrated the efficacy of oligonucleotide-mediated microRNAs (miRNA)/ long non-coding RNAs (lncRNA) silencing in enhancement of response of cancer cells to paclitaxel. Therefore, targeted therapies against non-coding RNAs have been suggested as applicable modalities for combatting resistance to this agent. In the present review, we provide a summary of studies which assessed the role of miRNAs and lncRNAs in conferring resistance to paclitaxel.

The Effect of Nanosystems on ATP-Binding Cassette Transporters: Understanding the Influence of Nanosystems on Multidrug Resistance Protein-1 and P-glycoprotein

The cancer multidrug resistance is involved in the failure of several treatments during cancer treatment. It is a phenomenon that has been receiving great attention in the last years due to the sheer amount of mechanisms discovered and involved in the process of resistance which hinders the effectiveness of many anti-cancer drugs. Among the mechanisms involved in the multidrug resistance, the participation of ATP-binding cassette (ABC) transporters is the main one. The ABC transporters are a group of plasma membrane and intracellular organelle proteins involved in the process of externalization of substrates from cells, which are expressed in cancer. They are involved in the clearance of intracellular metabolites as ions, hormones, lipids and other small molecules from the cell, affecting directly and indirectly drug absorption, distribution, metabolism and excretion. Other mechanisms responsible for resistance are the signaling pathways and the anti- and pro-apoptotic proteins involved in cell death by apoptosis. In this study we evaluated the influence of three nanosystem (Graphene Quantum Dots (GQDs), mesoporous silica (MSN) and poly-lactic nanoparticles (PLA)) in the main mechanism related to the cancer multidrug resistance such as the Multidrug Resistance Protein-1 and P-glycoprotein. We also evaluated this influence in a group of proteins involved in the apoptosis-related resistance including cIAP-1, XIAP, Bcl-2, BAK and Survivin proteins. Last, colonogenic and MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assays have also been performed. The results showed, regardless of the concentration used, GQDs, MSN and PLA were not cytotoxic to MDA-MB-231 cells and showed no impairment in the colony formation capacity. In addition, it has been observed that P-gp membrane expression was not significantly altered by any of the three nanomaterials. The results suggest that GQDs nanoparticles would be suitable for the delivery of other multidrug resistance protein 1 (MRP1) substrate drugs that bind to the transporter at the same binding pocket, while MSN can strongly inhibit doxorubicin efflux by MRP1. On the other hand, PLA showed moderate inhibition of doxorubicin efflux by MRP1 suggesting that this nanomaterial can also be useful to treat MDR (Multidrug resistance) due to MRP1 overexpression.

Preparation, Characterization, and Evaluation of Cisplatin-Loaded Polybutylcyanoacrylate Nanoparticles with Improved In Vitro and In Vivo Anticancer Activities

This study aimed to evaluate the therapeutic efficacy of the cisplatin encapsulated into polybutylcyanoacrylate (PBCA) nanoparticles for the treatment of kidney cancer. The nanoformulation was successfully developed using the miniemulsion polymerization method and characterized in terms of size, size distribution, drug loading and encapsulation efficiencies, drug release behavior, in vitro cytotoxicity effects, in vivo toxicity, and therapeutic effects. Cisplatin-loaded PBCA nanoparticles were confirmed to be in nanoscale with the drug entrapment efficiency of 23% and controlled drug release profile, in which only 9% of the loaded drug was released after 48 h. The nanoparticles caused an increase in the cytotoxicity effects of cisplatin against renal cell adenocarcinoma cells (ACHN) (2.3-fold) and considerably decreased blood urea nitrogen and creatinine concentrations when compared to the standard cisplatin (1.6-fold and 1.5-fold, respectively). The nanoformulation also caused an increase in the therapeutic effects of cisplatin by 1.8-fold, in which a reduction in the mean tumor size was seen (3.5 mm vs. 6.5 mm) when compared to the standard cisplatin receiver rats. Overall, cisplatin-loaded PBCA nanoparticles can be considered as a promising drug candidate for the treatment of kidney cancer due to its potency to reduce the side effects of cisplatin and its toxicity and therapeutic effects on cancer-bearing Wistar rats.

Recent developments on zinc(ii) metal-organic framework nanocarriers for physiological pH-responsive drug delivery

The high storage capacities and excellent biocompatibilities of zinc(ii) metal-organic frameworks (Zn-MOFs) have made them outstanding candidates as drug delivery carriers. Recent studies on the pH-responsive processes based on carrier-drug interactions have proven them to be the most efficient and effective way to control the release profiles of drugs. To satisfy the ever-growing demand in cancer therapy, great efforts are being devoted to the development of methods to precisely control drug release and achieve targeted use of an active substance at the right time and place. In this review article, we discuss the diverse stimuli based on Zn-MOFs carriers that have been achieved upon external activation from single pH-stimulus-responsive or/and multiple pH-stimuli-responsive viewpoints. Also, the perspectives and future challenges in this type of carrier system are discussed.

The ABCB1 3435C > T polymorphism influences docetaxel transportation in ovarian cancer

Objective

To investigate the effect of the ATP-binding cassette transporter superfamily B member 1 gene (ABCB1 ) 3435C > T single nucleotide polymorphism (SNP) on docetaxel transportation in ovarian cancer cells.

Methods

ES-2 and SKOV3 cells were transfected with an ABCB1 3435C > T recombinant plasmid, and mRNA expression was detected by real-time PCR. The MTT assay was used to detect the toxicity of docetaxel. High-performance liquid chromatography determined the drug concentration in different cell models to evaluate intracellular accumulation, and a transmembrane resistance experiment was used to assess permeability and evaluate the effect of P-gp activity on drug transportation. A tumor-bearing mouse model was established to evaluate the effect of ABCB1 3435C > T on docetaxel resistance.

Results

P-gp was overexpressed in cells transfected with the ABCB1 3435C > T plasmid, leading to a significant increase in drug resistance to docetaxel. ABCB1 3435C/wild-type transfection significantly promoted the transport of docetaxel mediated by P-gp compared with ABCB1 3435T/mutant transfection.

Conclusion

P-gp encoded by the ABCB1 variant allele appears to be more efficient at transporting docetaxel compared with the wild-type allele. The ABCB1 3435C > T SNP dramatically affected the efflux ability of P-gp against docetaxel, and may influence P-gp expression and activity.

Development and Characterization of Magnetite/Poly(butylcyanoacrylate) Nanoparticles for Magnetic Targeted Delivery of Cancer Drugs

A great attention is presently paid to the design of drug delivery vehicles based on surface-modified magnetic nanoparticles. They can, in principle, be directed to a desired target area for releasing their drug payload, a process triggered by pH, temperature, radiation, or even magnetic field. To this, the possibility of forming part of diagnostic tools by enhanced magnetic resonance imaging or that of further treatment by magnetic hyperthermia can be added. Bare particles are rapidly eliminated from the bloodstream by the phagocyte mononuclear system, leading to short biological half-life. It is hence required to coat them in order to increase their biocompatibility and facilitate the drug incorporation. In this work, magnetite nanoparticles were coated with poly(butylcyanoacrylate) (PBCA) manufactured and characterized with regard to their physical properties and their suitability as a platform for magnetically controlled drug delivery. The average diameter of magnetite and core-shell nanoparticles was 97 ± 19 and 140 ± 20 nm, respectively. Infrared analysis, electrophoretic mobility, surface thermodynamics analysis, and X-ray diffraction all confirmed that the magnetic particles were sufficiently covered by the polymer in the composite nanoparticles. In addition, assays using normal (CCD-18 and MCF-10A) and tumoral (T-84 and MCF-7) cell lines derived from colon and breast tissue, respectively, demonstrated that nanocomposites have low or negligible cytotoxicity. It is concluded that PBCA-coated magnetite core-shell nanoparticles represent a remarkable promise as a platform for magnetically controlled drug delivery.

Optimization of paeonol-loaded poly(butyl-2-cyanoacrylate) nanocapsules by central composite design with response surface methodology together with the antibacterial properties

With the aim to enhance dissolution rate and bioavailability of paeonol, paeonol-loaded poly(butyl-2-cyanoacrylate) nanocapsules (Pae@PNCs) were prepared by interfacial spontaneous polymerization for the first time. Herein, a rotatable central composite design (RCCD) with three-factor five-level was applied to evaluate the optimization experiments. To the maximum percentage encapsulation efficiency (EE%) and minimum particle size (nm) of the Pae@PNCs, a quadratic polynomial model was generated to predict and evaluate the independent variables with respect to the dependent variables. RSM model goodness fitting were confirmed by the ANOVA Table (P<0.05) through variance analysis, which predicted values of EE (%) and particle size (R² and adjusted R² were close to 1, respectively) in good agreement with experimental values. By solving the regression equation and analyzing the response surface, three-dimensional model graphs and plots, the optimal result for the preparation of Pae@PNCs were found to be: pH (2.34), Poloxamer F-68 (0.80% m/v) and ethyl acetate/α-BCA ratio (16.67 v/v) for the highest EE% (73.58±2.76%) and the smallest particle size (42.06±1.20nm). The release profiles and antibacterial activity in vitro from the optimal Pae@PNCs were performed. The results indicated that it has slow and well-controlled release, and has strong antibacterial activity in vitro than paeonol. This understanding can help to predict the conditions of optimization of poly(butyl-2-cyanoacrylate) nanoparticles formation and to improve paeonol bioavailability and pharmacological properties.

Efficient antitumor effect of co-drug-loaded nanoparticles with gelatin hydrogel by local implantation

Tetrandrine (Tet) could enhance the antitumor effect of Paclitaxel (Ptx) by increasing intracellular Reactive Oxygen Species (ROS) levels, which leads to the possibility of co-delivery of both drugs for synergistic antitumor effect. In the current study, we reported an efficient, local therapeutic strategy employing effective Tet and Ptx delivery with a nanoparticle-loaded gelatin system. Tet- and Ptx co-loaded mPEG-PCL nanoparticles (P/T-NPs) were encapsulated into the physically cross-linked gelatin hydrogel and then implanted on the tumor site for continuous drug release. The drug-loaded gelatin hydrogel underwent a phase change when the temperature slowly increased. In vitro study showed that Tet/Ptx-loaded PEG-b-PCL nanoparticles encapsulated within a gelatin hydrogel (P/T-NPs-Gelatin) inhibited the growth and invasive ability of BGC-823 cells more effectively than the combination of free drugs or P/T-NPs. In vivo study validated the therapeutic potential of P/T-NPs-Gelatin. P/T-NPs-Gelatin significantly inhibited the activation of p-Akt and the downstream anti-apoptotic Bcl-2 protein and also inducing the activation of pro-apoptotic Bax protein. Moreover, the molecular-modulating effect of P/T-NPs-Gelatin on related proteins varied slightly under the influence of NAC, which was supported by the observations of the tumor volumes and weights. Based on these findings, local implantation of P/T-NPs-Gelatin may be a promising therapeutic strategy for the treatment of gastric cancer.

Nanoparticle-dendrimer hybrid nanocapsules for therapeutic delivery

BACKGROUND

Nanocapsules can efficiently encapsulate therapeutic cargo for anticancer drug delivery. However, the controlled release of the payload remains a challenge for effective drug delivery.

MATERIALS & METHODS

We used dithiocarbamate-functionalized PAMAM dendrimer to cross-link the shell of arginine gold nanoparticles stabilized nanocapsule, and controlled the drug release from the nanocapsule. The ability of cross-linked nanocapsule to deliver hydrophobic paclitaxel to B16F10 cells was demonstrated both in vitro and in vivo.

RESULTS

Cross-linked nanocapsule possesses tunable stability and modular permeability, and can deliver paclitaxel with improved anticancer efficiency compared with free drug both in vitro and in vivo.

CONCLUSION

Dithiocarbamate chemistry provides a new tool to harness multifactorial colloidal self-assembly for controlled drug delivery for cancer therapy.

Exploring the use of nanocarrier systems to deliver the magical molecule; Curcumin and its derivatives

Curcumin and its derivatives; curcuminoids have been proven as potential remedies in different diseases. However, their delivery carries several challenges owing to their poor aqueous solubility, photodegradation, chemical instability, poor bioavailability and rapid metabolism. This review explores and criticizes the numerous attempts that were adopted through the years to entrap/encapsulate this valuable drug in nanocarriers aiming to reach its most appropriate and successful delivery system.

Enhanced antitumoral activity of doxorubicin against lung cancer cells using biodegradable poly(butylcyanoacrylate) nanoparticles

Doxorubicin (Dox) is widely used for the combined chemotherapy of solid tumors. However, the use of these drug associations in lung cancer has low antitumor efficacy. To improve its efficacious delivery and activity in lung adenocarcinoma cells, we developed a biodegradable and noncytotoxic nanoplatform based on biodegradable poly(butylcyanoacrylate) (PBCA). The reproducible formulation method was based on an anionic polymerization process of the PBCA monomer, with the antitumor drug being entrapped within the nanoparticle (NP) matrix during its formation. Improved drug-entrapment efficiencies and sustained (biphasic) drug-release properties were made possible by taking advantage of the synthesis conditions (drug, monomer, and surfactant-agent concentrations). Dox-loaded NPs significantly enhanced cellular uptake of the drug in the A549 and LL/2 lung cancer cell lines, leading to a significant improvement of the drug's antitumoral activity. In vivo studies demonstrated that Dox-loaded NPs clearly reduced tumor volumes and increased mouse-survival rates compared to the free drug. These results demonstrated that PBCA NPs may be used to optimize the antitumor activity of Dox, thus exhibiting a potential application in chemotherapy against lung adenocarcinoma.

Poly(butylcyanoacrylate) and Poly(ε-caprolactone) Nanoparticles Loaded with 5-Fluorouracil Increase the Cytotoxic Effect of the Drug in Experimental Colon Cancer

The clinical use of 5-fluorouracil, one of the drugs of choice in colon cancer therapy, is limited by a nonuniform oral absorption, a short plasma half-life, and by the development of drug resistances by malignant cells. We hypothesized that the formulation of biodegradable nanocarriers for the efficient delivery of this antitumor drug may improve its therapeutic effect against advanced or recurrent colon cancer. Hence, we have engineered two 5-fluorouracil-loaded nanoparticulate systems based on the biodegradable polymers poly(butylcyanoacrylate) and poly(ε-caprolactone). Drug incorporation to the nanosystems was accomplished by entrapment (encapsulation/dispersion) within the polymeric network during nanoparticle synthesis, i.e., by anionic polymerization of the monomer and interfacial polymer disposition, respectively. Main factors determining 5-fluorouracil incorporation within the polymeric nanomatrices were investigated. These nanocarriers were characterized by high drug entrapment efficiencies and sustained drug-release profiles. In vitro studies using human and murine colon cancer cell lines demonstrated that both types of nanocarriers significantly increased the antiproliferative effect of the encapsulated drug. In addition, both nanoformulations produced in vivo an intense tumor growth inhibition and increased the mice survival rate, being the greater tumor volume reduction obtained when using the poly(ε-caprolactone)-based formulation. These results suggest that these nanocarriers may improve the antitumor activity of 5-fluorouracil and could be used against advanced or recurrent colon cancer.

Nanoscale drug delivery for taxanes based on the mechanism of multidrug resistance of cancer

Taxanes are one type of the most extensively used chemotherapeutic agents to treat cancers. However, their clinical use is severely limited by intrinsic and acquired resistance. A diverse variety of mechanisms has been implicated about taxane resistance, such as alterations of drug targets, overexpression of efflux transporters, defective apoptotic machineries, and barriers in drug transport. The deepening understanding of molecular mechanisms of taxane resistance has spawned a number of targets for reversing resistance. However, circumvention of taxane resistance would not only possess therapeutic potential, but also face with clinical challenge, which accelerates the development of optimal nanoscale delivery systems. This review highlights the current understanding on the mechanisms of taxane resistance, and provides a comprehensive analysis of various nanoscale delivery systems to reverse taxane resistance.

Nanotechnology-based drug delivery systems for treatment of oral cancer: a review

Oral cancer (oral cavity and oropharynx) is a common and aggressive cancer that invades local tissue, can cause metastasis, and has a high mortality rate. Conventional treatment strategies, such as surgery and chemoradiotherapy, have improved over the past few decades; however, they remain far from optimal. Currently, cancer research is focused on improving cancer diagnosis and treatment methods (oral cavity and oropharynx) nanotechnology, which involves the design, characterization, production, and application of nanoscale drug delivery systems. In medicine, nanotechnologies, such as polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, gold nanoparticles, hydrogels, cyclodextrin complexes, and liquid crystals, are promising tools for diagnostic probes and therapeutic devices. The objective of this study is to present a systematic review of nanotechnology-based drug delivery systems for oral cancers.

Rationally designed nanovehicles to overcome cancer chemoresistance

Drug resistance is a primary hindrance towards curative cancer chemotherapy. Nanotechnology holds great promise in establishing efficacious and innovative strategies to overcome chemoresistance, and markedly facilitate complementary treatments and cancer diagnostics. Various nanomedical devices are being introduced and evaluated, demonstrating encouraging results. While stealth liposomes serve as a benchmark, astonishing progress is witnessed in polymeric nanovehicles, sometimes combined with low molecular weight surfactants, some of which inhibit drug resistance in addition to solubilizing drugs. Cutting edge multifunctional or quadrugnostic nanoparticles currently developed offer simultaneous targeted delivery of chemotherapeutics and chemosensitizers or drug-resistance gene silencing cargo, along with diagnostic imaging agents, like metallic NPs. Viral and cellular components offer exciting new routes for cancer targeting and treatment. Targeting intracellular compartments is another challenging frontier spawning pioneering approaches and results. To further enhance rational design of nanomedicine for overcoming drug resistance, we review the latest thoughts and accomplishments in recent literature.

Grape seed procyanidin reversal of p-glycoprotein associated multi-drug resistance via down-regulation of NF-κB and MAPK/ERK mediated YB-1 activity in A2780/T cells

The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multi-drug resistance (MDR), leading chemotherapy failure of patients suffered with cancer. Grape seed procyanidin(GSP) is a natural polyphenol supplement with anti-inflammatory effect. Present study assessed a new use of GSP on the MDR reversal activity and its possible molecular mechanisms in MDR1-overpressing paclitaxel resistant ovarian cancer cells. Our results showed GSP significantly enhanced the cytotoxicity of paclitaxel and adriamycin in paclitaxel resistant A2780/T cells but its parental A2780 cells. Furthermore, GSP strongly inhibited P-gp expression by blocking MDR1 gene transcription, as well as, increased the intracellular accumulation of the P-gp substrate rhodamine-123 in A2780/T cells. Nuclear factor-κB(NF-κB) activity, IκB degradation level and NF-κB/p65 nuclear translocation induced by lipopolysaccharide (LPS) and receptor activator for nuclear factor-κB ligand (RANKL) were markedly inhibited by pre-treatment with GSP. Meanwhile, GSP inhibited MAPK/ERK pathway by decreasing the phosphorylation of ERK1/2, resulting in reduced the Y-box binding protein 1 (YB-1) activation with blocking its nuclear translocation. Moreover, the up-regulation of P-gp expression, the activation of AKT/NF-κB and MAPK/ERK pathway induced by LPS was attenuated by GSP administration. Compared with PDTC and U1026, inhibitor of NF-κB and MAPK/ERK respectively, GSP showed the same tendency of down-regulating NF-κB and MAPK/ERK mediated YB-1 activities. Thus, GSP reverses P-gp associated MDR by inhibiting the function and expression of P-gp through down-regulation of NF-κB activity and MAPK/ERK pathway mediated YB-1 nuclear translocation, offering insight into the mechanism of reversing MDR by natural polyphenol supplement compounds. GSP could be a new potential MDR reversal agent used for combination therapy with chemotherapeutics in clinic.

Recent trends in cancer drug resistance reversal strategies using nanoparticles

INTRODUCTION

Resistance to chemotherapy is a major obstacle in the successful amelioration of tumors in many cancer patients. Resistance is either intrinsic or acquired, involving mechanisms such as genetic aberrations, decreased influx and increased efflux of drugs. Strategies for the reversal of resistance involve the alteration of enzymes responsible for drug resistance, the modulation of proteins regulating apoptosis mechanisms and improving the uptake of drugs using nanotechnology. Novel strides in the reversal of drug resistance are emerging, involving the use of nanotechnology, targeting stem cells, etc.

AREAS COVERED

This paper reviews the most recent cancer drug reversal strategies involving nanotechnology for targeting cancer cells and cancer stem cells (CSCs), for enhanced uptake of micro- and macromolecular inhibitors.

EXPERT OPINION

Nanotechnology used in conjunction with existing therapies, such as gene therapy and P-glycoprotein inhibition, has been shown to improve the reversal of drug resistance; the mechanisms involved in this include specific targeting of drugs and nucleotide therapeutics, enhanced cellular uptake of drugs and improved bioavailability of drugs with poor physicochemical characteristics. Important strategies in the reversal of drug resistance include: a multifunctional nanoparticulate system housing a targeting moiety; therapeutics to kill resistant cancer cells and CSCs; cytotoxic drugs and a tumor microenvironment stimuli-responsive element, to release the encapsulated therapeutics.

Spray-dried chitosan microparticles for cellular delivery of an antigenic protein: physico-chemical properties and cellular uptake by dendritic cells and macrophages

PURPOSE

Spray-dried chitosan microparticles for cellular delivery of antigen to dendritic cells (DC) and macrophages (Mϕ) were investigated.

METHODS

Chitosan microparticles were prepared by spray drying. For comparison, poly(lactic-co-glycolic acid) (PLGA) and poly(α-butyl cyanoacrylate) (BCA) micro-/nanoparticles were generated. Bovine serum albumin (BSA) was used as a model antigen. The particles were characterized in terms of size, morphology, surface charge, surface composition, protein content, entrapment efficiency, in vitro release, and protein integrity. Additionally, they were subject to cell viability and cellular uptake study with DC and Mϕ.

RESULTS

Size of chitosan, PLGA, and BCA micro-/nanoparticles ranged between 3.11-7.18, 0.94-6.26, and 0.30-6.34 μm, respectively. Particle morphology and in vitro protein release varied, depending on polymer type, particle composition and preparation process parameters. Chitosan microparticles were cationic, while PLGA microparticles were neutral. BCA micro-/nanoparticles were either anionic or cationic, according to polymerization pH. Protein content and entrapment efficiency of chitosan and PLGA microparticles were relatively consistent. Only integrity and conformational structure of protein encapsulated in chitosan microparticles were completely retained. Chitosan and PLGA microparticles were non-toxic to DC and Mϕ, but the former were internalized more efficiently.

CONCLUSIONS

Spray-dried chitosan microparticles delivered the antigen efficiently to DC and Mϕ.

Key structure of brij for overcoming multidrug resistance in cancer

Multidrug resistance (MDR) is a major barrier to the chemotherapy treatment of many cancers. However, some nonionic surfactants, for example, Brij, have been shown to restore the sensitivity of MDR cells to such drugs. The aim of this study was to explore the reversal effect of Brij on MDR tumor cells and elucidate its potential mechanism. Our data indicate that the structure of Brij surfactants plays an important role in overcoming MDR in cancer, that is, modified hydrophilic-lipophilic balance (MHLB, the ratio of the number (n) of hydrophilic repeating units of ethylene oxide (EO) to the number (m) of carbons in the hydrophobic tail (CH(2))). Cell viability of cells treated with paclitaxel (PTX) nanocrystals (NCs) formulated with Brij showed positive correlations with MHLB (R(2) = 0.8195); the higher the ratio of Brij to PTX in NCs, the higher cytotoxicity induced by the PTX NCs. Significant increases in intracellular accumulation of (3)H-PTX (P-gp substrate) were observed in an MDR cell line (H460/taxR cells) treated with Brij 78 (MHLB = 1.11) and Brij 97 (MHLB = 0.6). After treatments with Brij 78 and Brij 97, the levels of intracellular ATP were decreased and verapamil-induced ATPase activities of P-gp were inhibited in multidrug resistant cells. The responses of the cells to Brij 78 and Brij 97 in ATP depletion studies correlated with the cell viability induced by PTX/Brij NCs and intracellular accumulation of (3)H-PTX. Brij 78 and Brij 97 could not alter the levels of P-gp expression detected by Western blotting. These findings may provide some insight into the likelihood of further development of more potent P-gp inhibitors for the treatment of MDR in cancer.

Bypassing multidrug resistance in human breast cancer cells with lipid/polymer particle assemblies

Background

Multidrug resistance (MDR) mediated by the overexpression of adenosine triphosphate (ATP)-binding cassette (ABC) transporters, such as P-glycoprotein (P-gp), remains one of the major obstacles to effective cancer chemotherapy. In this study, lipid/particle assemblies named LipoParticles (LNPs), consisting of a dimethyldidodecylammonium bromide (DMAB)-modified poly(lactic-co-glycolic acid) (PLGA) nanoparticle core surrounded by a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) shell, were specially designed for anticancer drugs to bypass MDR in human breast cancer cells that overexpress P-gp.

Methods

Doxorubicin (DOX), a chemotherapy drug that is a P-gp substrate, was conjugated to PLGA and encapsulated in the self-assembled LNP structure. Physiochemical properties of the DOX-loaded LNPs were characterized in vitro. Cellular uptake, intracellular accumulation, and cytotoxicity were compared in parental Michigan Cancer Foundation (MCF)-7 cells and P-gp-overexpressing, resistant MCF-7/adriamycin (MCF-7/ADR) cells.

Results

This study found that the DOX formulated in LNPs showed a significantly increased accumulation in the nuclei of drug-resistant cells relative to the free drug, indicating that LNPs could alter intracellular traffic and bypass drug efflux. The cytotoxicity of DOX loaded-LNPs had a 30-fold lower half maximal inhibitory concentration (IC₅₀) value than free DOX in MCF-7/ADR, measured by the colorimetric cell viability (MTT) assay, correlated with the strong nuclear retention of the drug.

Conclusion

The results show that this core-shell lipid/particle structure could be a promising strategy to bypass MDR.