Nanomedicine therapeutic approaches to overcome cancer drug resistance

Overcome Cancer Cell Drug Resistance Using Natural Products

Chemotherapy is one of the major treatment methods for cancer. However, failure in chemotherapy is not uncommon, mainly due to dose-limiting toxicity associated with drug resistance. Management of drug resistance is important towards successful chemotherapy. There are many reports in the Chinese literature that natural products can overcome cancer cell drug resistance, which deserve sharing with scientific and industrial communities. We summarized the reports into four categories: (1) in vitro studies using cell line models; (2) serum pharmacology; (3) in vivo studies using animal models; and (4) clinical studies. Fourteen single compounds were reported to have antidrug resistance activity for the first time. In vitro, compounds were able to overcome drug resistance at nontoxic or subtoxic concentrations, in a dose-dependent manner, by inhibiting drug transporters, cell detoxification capacity, or cell apoptosis sensitivity. Studies in vivo showed that single compounds, herbal extract, and formulas had potent antidrug resistance activities. Importantly, many single compounds, herbal extracts, and formulas have been used clinically to treat various diseases including cancer. The review provides comprehensive data on use of natural compounds to overcome cancer cell drug resistance in China, which may facilitate the therapeutic development of natural products for clinical management of cancer drug resistance.

Advances in Imaging: Brain Tumors to Alzheimer's Disease

Professor Black and colleagues have been working to improve the quality and sensitivity of imaging in the early detection of conditions from brain tumors to Alzheimer's disease to enhance treatment protocols and patient management. Professor Black et al introduced nanoparticles to improve MRI imaging. These nanoparticles consist of poly (b-L- malic acid (PMLA)) conjugates with monoclonal antibodies ((mAbs)) and Gd-DOTA. These are known as MRI nano-imaging agents (NIA). Most importantly, they can penetrate the endothelial blood-brain barrier (BBB) to reach brain tumors (primary or metastasis). This is effective in cases of brain tumors or breast cancer or other cancers such as lung cancer and gastric cancer having HER2 and/or EGFR positive crossing BBB. By the covalent conjugation of MR contrast (NIA), the MRI virtual biopsy can differentiate brain tumors from infections or other brain pathological conditions. The brain's intrinsic natural fluorescence such as NADH, FAD, lipopigments and porphyrin in the brain tissue can be identified by using time resolved fluorescence spectroscopy (TRFS) which is operated through the use of ultra-short laser. TRFS produces various color bands to differentiate the tumor from normal brain tissue in real time and registers the data on a 3D map. This is significant, as this will provide a greatly improved assessment methodology of tissue type. Consequently, this will potentially result in shorter operation times as well as more satisfactory tumor removal. In the detection of Alzheimer disease, amyloid plaque is deposited in retina tissue (including the RGC, RNFL and inner plexiform layer) which can produce a fluorescence effect by using curcumin as a contrast. This is then shown by human retina amyloid imaging device. Immunotherapies with glatiramer acetate (GA) have been shown to reduce amyloid deposits in brain and retinal AB deposits in mice. The study of advanced imaging technology and techniques including NIA, TRFS and the detection of amyloid plaque in Alzheimer disease are very important approaches to create a new era for diagnostic and therapeutic management of brain tumors and other cancers (HER2 and/or EGFR positive). This pioneering work by Professor Black, and colleagues, gives rise to a new hope for cancer patients for targeted therapy and for immunotherapies in Alzheimer's disease.

Construction and characterization of an anti-CD20 mAb nanocomb with exceptionally excellent lymphoma-suppressing activity

The CD20-directed monoclonal antibody rituximab (RTX) established a new era in the treatment of non-Hodgkin lymphoma (NHL); however, suboptimal response and/or resistance to RTX still limit its clinical merits. Although four effector mechanisms are validated to participate in CD20-based immunotherapy, including complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, caspase-dependent apoptosis, and lysosome-mediated programmed cell death (PCD), they could hardly be synchronously activated by any anti-CD20 mAb or mAb derivative until now. Herein, a novel mAb nanocomb (polyethylenimine polymer–RTX–tositumomab [PPRT nanocomb]) was firstly constructed through mass arming two different anti-CD20 mAbs (RTX and tositumomab) to one polymer by nanotechnology. Comparing with free mAbs, PPRT nanocomb possesses a comparable binding ability and reduced “off-rate” to surface CD20 of NHL cells. When treated by PPRT nanocomb, the caspase-dependent apoptosis was remarkably enhanced except for concurrently eliciting complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and lysosome-mediated PCD. Besides, “cross-cell link”-assisted homotypic adhesion by PPRT nanocomb further enhanced the susceptibility to PCD of lymphoma cells. Pharmacokinetic assays revealed that PPRT nanocomb experienced a relatively reduced clearance from peripheral blood compared with free antibodies. With the cooperation of all the abovementioned superiorities, PPRT nanocomb exhibits exceptionally excellent in vivo antitumor activities in both disseminated and localized human NHL xenotransplant models.

Nanocarriers with tunable surface properties to unblock bottlenecks in systemic drug and gene delivery

Nanocarrier-mediated drug and gene delivery systems hold great promise for providing more refined delivery (especially in cancer treatments) to maximize therapeutic efficacy while minimizing unfavorable side effects. Despite their promise, the highly effective transport of therapeutics in vivo remains a challenge. Over the last 20years, there has been a large amount of research directed toward the development of a multitude of nanocarriers for drug and gene delivery, but only a very small part has progressed into clinical trials. This suggests that the properties of current nanocarriers are not yet ideal for effective drug and gene delivery in vivo. Nanocarrier-mediated drug and gene delivery is a multi-step process, and inefficient delivery at any stage would ultimately result in an unsuccessful delivery. Unfortunately, existing nanocarriers with fixed surface properties, such as a PEGylated, cationized and bioconjugated surface, are not versatile enough to overcome the extracellular and intracellular barriers which require different surface properties. Consequently, their delivery efficacy is not optimal, leading to doubts and debates on the value of nanocarrier-based product development. To resolve the "fixed surface dilemma", the switchable surfaces of nanocarriers, which can surmount both extracellular and intracellular barriers, open up the possibility of highly efficient delivery in vivo. Here, we review and highlight the recent developments in the design of nanocarrier delivery systems with tunable surface properties in response to microenvironment triggers. Strategies including zwitterionic nanocarriers, polymer brushes, layer-by-layer nanocarriers and cleavable conjugated nanocarriers are presented. These representative examples and their respective outcomes elaborate the benefits and efficiencies of these nanocarriers at the individual stages of drug and gene delivery.

miRNA therapy targeting cancer stem cells: a new paradigm for cancer treatment and prevention of tumor recurrence

Cancer stem cells (CSCs) are a small subpopulation of cells within tumors that retain the properties of self-renewal and tumorigenicity in vivo. Although CSCs have been reported in multiple cancers, the regulation of CSCs has not been described at the molecular level. miRNAs are endogenous small noncoding RNAs that post-transcriptionally regulate the expression of their target genes via RNA interference and are involved in almost all cellular processes. Since aberrant miRNA expression occurs in CSCs, such dysregulated miRNAs may be promising therapeutic targets. In this review, we summarize the current knowledge regarding miRNAs that regulate CSC properties and discuss an in vivo delivery system for synthetic miRNA mimics and miRNA inhibitors for the development of innovative miRNA therapy against CSCs.

The emerging applications of magnetic nanovectors in nanomedicine

The scientific disciplines that encompass medical therapy and diagnostics, in a continuing transition to personalized medicine, have found a valuable tool in the emerging field of nanotechnology. New nanotools are now enabling discoveries and advancements that form the foundation of what has become known collectively as nanomedicine. The global impact of these advancements are being seen in areas of advanced/improved early stage diagnostics, targeted drug delivery systems and imaging methods, all leading to more effective diagnostic/therapeutic strategies and outcomes. This review focuses on recent patent advancements in this transition with emphasis on the emerging role of magnetic nanovectors as enabling tools for the enhanced effectiveness of cancer diagnostics and therapeutics, considering its historical progression and future impact.

Targeted multidrug-resistance reversal in tumor based on PEG-PLL-PLGA polymer nano drug delivery system

The study investigated the reversal of multidrug resistance (MDR) and the biodistribution of nanoparticles (NPs) that target leukemia cells in a nude mice model via a surface-bound transferrin (Tf). The cytotoxic cargo of daunorubicin (DNR) and tetrandrine (Tet) was protected in the NPs by an outer coat composed of polyethylene glycol (PEG)-poly-l-lysine (PLL)-poly(lactic-co-glycolic acid) (PLGA) NPs. Injection of DNR-Tet-Tf-PEG-PLL-PLGA NPs into nude mice bearing MDR leukemia cell K562/A02 xenografts was shown to inhibit tumor growth, and contemporaneous immunohistochemical analysis of tumor tissue showed the targeted NPs induced apoptosis in tumor cells. Targeted tumor cells exhibited a marked increase in Tf receptor expression, with noticeable decreases in P-glycoprotein, MDR protein, and nuclear factor κB, as assessed by quantitative real-time polymerase chain reaction and Western blot analysis. Moreover, the concentration of DNR was shown to increase in plasma, tumor tissue, and major organs. Flow cytometry analysis with a near-infrared fluorescent (NIRF) dye, NIR797, was used to study the effectiveness of Tf as a targeting group for leukemia cells, a finding that was supported by NIRF imaging in tumor-bearing nude mice. In summary, our studies show that DNR-Tet-Tf-PEG-PLL-PLGA NPs provide a specific and effective means to target cytotoxic drugs to MDR tumor cells.

MRI virtual biopsy and treatment of brain metastatic tumors with targeted nanobioconjugates: nanoclinic in the brain

Differential diagnosis of brain magnetic resonance imaging (MRI) enhancement(s) remains a significant problem, which may be difficult to resolve without biopsy, which can be often dangerous or even impossible. Such MRI enhancement(s) can result from metastasis of primary tumors such as lung or breast, radiation necrosis, infections, or a new primary brain tumor (glioma, meningioma). Neurological symptoms are often the same on initial presentation. To develop a more precise noninvasive MRI diagnostic method, we have engineered a new class of poly(β-l-malic acid) polymeric nanoimaging agents (NIAs). The NIAs carrying attached MRI tracer are able to pass through the blood-brain barrier (BBB) and specifically target cancer cells for efficient imaging. A qualitative/quantitative "MRI virtual biopsy" method is based on a nanoconjugate carrying MRI contrast agent gadolinium-DOTA and antibodies recognizing tumor-specific markers and extravasating through the BBB. In newly developed double tumor xenogeneic mouse models of brain metastasis this noninvasive method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. After MRI diagnosis, breast and lung cancer brain metastases were successfully treated with similar tumor-targeted nanoconjugates carrying molecular inhibitors of EGFR or HER2 instead of imaging contrast agent. The treatment resulted in a significant increase in animal survival and markedly reduced immunostaining for several cancer stem cell markers. Novel NIAs could be useful for brain diagnostic MRI in the clinic without currently performed brain biopsies. This technology shows promise for differential MRI diagnosis and treatment of brain metastases and other pathologies when biopsies are difficult to perform.

Phase-change material filled hollow magnetic nanoparticles for cancer therapy and dual modal bioimaging

To develop carriers for anti-cancer drug delivery, this study reports a biocompatible and thermal responsive controlled drug delivery system based on hollow magnetic nanoparticles (HMNPs). The system is constructed simply by filling the hollow interiors of HMNPs with a phase-change material (PCM), namely, 1-tetradecanol, which has a melting point of 38 °C. The system achieves near "zero release" of both hydrophobic paclitaxel (PTX) and hydrophilic doxorubicin hydrochloride (DOX) and precise "on" or "off" drug delivery in vitro to efficiently induce cell apoptosis. Furthermore, the system displays both infrared thermal imaging and magnetic resonance imaging properties. More importantly, the system demonstrates great potential for thermo-chemo combination cancer therapy in vivo when an alternating magnetic field is applied.

Enhancing Accumulation and Penetration of HPMA Copolymer-Doxorubicin Conjugates in 2D and 3D Prostate Cancer Cells via iRGD Conjugation with an MMP-2 Cleavable Spacer

To enhance the accumulation and penetration of nanomedicines in tumor tissue, we developed and evaluated the biological properties of matrix metalloproteinase 2 (MMP-2)-responsive N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer drugs and tumor-penetrating peptide conjugates (P-DOX-PLGLAG-iRGD). Two different spacers were used in the design: a lysosomally (cathepsin B) cleavable tetrapeptide GFLG spacer conjugated doxorubicin (DOX) to HPMA copolymer, and an MMP-2-degradable linker (PLGLAG) connected tumor-homing and -penetrating cyclic peptide iRGD to HPMA copolymer. The accumulation of DOX in P-DOX-PLGLAG-iRGD-treated monolayer (2D) and multilayer (3D) DU-145 prostate cancer cells was higher than that of control groups (P-DOX and P-DOX + iRGD). The cell cycle arrest analysis and cytotoxicity data demonstrated that P-DOX-PLGLAG-iRGD produced a higher G2/M arrest and possessed stronger cytotoxicity against DU-145 cells than P-DOX + iRGD or P-DOX, which was consistent with the drug uptake results. Similarly, P-DOX-PLGLAG-iRGD demonstrated the highest penetration ability in 3D multicellular DU-145 tumor cell spheroids. The results indicate that covalent conjugation of iRGD via MMP-2-sensitive bonds enhances accumulation and penetration of nanomedicines into tumor cell monolayers and spheroids.

Active Drug Targeting of a Folate-Based Cyclodextrin-Doxorubicin Conjugate and the Cytotoxic Effect on Drug-Resistant Mammary Tumor Cells In Vitro

Active drug targeting is an effective therapeutic approach for the treatment of malignant cancers and novel types of drug carriers have been developed. In this study, we developed a cyclodextrin (CD)-based novel carrier-drug conjugate, called per-FOL-β-CD-ss-DOX, which has folic acid (FA) molecules at the end of primary hydroxyl groups of β-CD and a pH-cleavable spacer with an anticancer drug, doxorubicin (DOX), at the end of secondary hydroxyl groups. This per-FOL-β-CD-ss-DOX exhibited a significant cellular uptake as compared with the free DOX solution by EMT6/P cells, which activate the expression of folate receptor (FR). Cellular uptake of per-FOL-β-CD-ss-DOX was significantly inhibited in the presence of FA and was also inhibited at 4°C. The conjugate exhibited remarkable cytotoxic effects in EMT6/AR1 cells, which are resistant to DOX, whereas free DOX solution did not exhibit this effect. These results suggest that per-FOL-β-CD-ss-DOX can be taken up into cells via FR-related endocytosis and the cleaved DOX derived from it in endosomes could escape the efflux caused by P-glycoprotein, resulting in the cytotoxic effect. Therefore, the drug delivery by per-FOL-β-CD-ss-DOX may be a useful approach for drug delivery to FR-expressing cells such as drug-resistant malignant cancers.

Biodegradable nanoparticles sequentially decorated with Polyethyleneimine and Hyaluronan for the targeted delivery of docetaxel to airway cancer cells

Background

Novel polymeric nanoparticles (NPs) specifically designed for delivering chemotherapeutics in the body and aimed at improving treatment activity and selectivity, cover a very relevant area in the field of nanomedicine.

Here, we describe how to build a polymer shell of Hyaluronan (HA) and Polyethyleneimine (PEI) on biodegradable NPs of poly(lactic-co-glycolic) acid (PLGA) through electrostatic interactions and to achieve NPs with unique features of sustained delivery of a docetaxel (DTX) drug cargo as well as improved intracellular uptake.

Results

A stable PEI or HA/PEI shell could be obtained by careful selection of layering conditions. NPs with exquisite stability in salt and protein-rich media, with size and surface charge matching biological requirements for intravenous injection and endowed with sustained DTX release could be obtained. Cytotoxicity, uptake and activity of both PLGA/PEI/HA and PLGA/PEI NPs were evaluated in CD44(+) (A549) and CD44(−) (Calu-3) lung cancer cells. In fact, PEI-coated NPs can be formed after degradation/dissociation of the surface HA because of the excess hyaluronidases overexpressed in tumour interstitium. There was no statistically significant cytotoxic effect of PLGA/PEI/HA and PLGA/PEI NPs in both cell lines, thus suggesting that introduction of PEI in NP shell was not hampered by its intrinsic toxicity. Intracellular trafficking of NPs fluorescently labeled with Rhodamine (RHO) (RHO-PLGA/PEI/HA and RHO-PLGA/PEI NPs) demonstrated an increased time-dependent uptake only for RHO-PLGA/PEI/HA NPs in A549 cells as compared to Calu-3 cells. As expected, RHO-PLGA/PEI NP uptake in A549 cells was comparable to that observed in Calu-3 cells. RHO-PLGA/PEI/HA NPs internalized into A549 cells showed a preferential perinuclear localization. Cytotoxicity data in A549 cells suggested that DTX delivered through PLGA/PEI/HA NPs exerted a more potent antiproliferative activity than free DTX. Furthermore, DTX-PLGA/PEI NPs, as hypothetical result of hyaluronidase-mediated degradation in tumor interstitium, were still able to improve the cytotoxic activity of free DTX.

Conclusions

Taken together, results lead us to hypothesize that biodegradable NPs coated with a PEI/HA shell represent a very promising system to treat CD44 overexpressing lung cancer. In principle, this novel nanocarrier can be extended to different single drugs and drug combinations taking advantage of the shell and core properties.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-015-0088-2) contains supplementary material, which is available to authorized users.

Redox-responsive polymer-drug conjugates based on doxorubicin and chitosan oligosaccharide-g-stearic acid for cancer therapy

Here, a biodegradable polymer-drug conjugate of doxorubicin (DOX) conjugated with a stearic acid-grafted chitosan oligosaccharide (CSO-SA) was synthesized via disulfide linkers. The obtained polymer-drug conjugate DOX-SS-CSO-SA could self-assemble into nanosized micelles in aqueous medium with a low critical micelle concentration. The size of the micelles was 62.8 nm with a narrow size distribution. In reducing environments, the DOX-SS-CSO-SA could rapidly disassemble result from the cleavage of the disulfide linkers and release the DOX. DOX-SS-CSO-SA had high efficiency for cellular uptake and rapidly released DOX in reductive intracellular environments. In vitro antitumor activity tests showed that the DOX-SS-CSO-SA had higher cytotoxicity against DOX-resistant cells than free DOX, with reversal ability up to 34.8-fold. DOX-SS-CSO-SA altered the drug distribution in vivo, which showed selectively accumulation in tumor and reduced nonspecific accumulation in hearts. In vivo antitumor studies demonstrated that DOX-SS-CSO-SA showed efficient suppression on tumor growth and relieved the DOX-induced cardiac injury. Therefore, DOX-SS-CSO-SA is a potential drug delivery system for safe and effective cancer therapy.

BCR/ABL mRNA targeting small interfering RNA effects on proliferation and apoptosis in chronic myeloid leukemia

BACKGROUND

To investigate the effects of small interference RNA (siRNA) targeting BCR/ABL mRNA on proliferation and apoptosis in the K562 human chronic myeloid leukemia (CML) cell line and to provide a theoretical rationale and experimental evidence for its potential clinical application for anti-CML treatment.

MATERIALS AND METHODS

The gene sequence for BCR/ABL mRNA was found from the GeneBank. The target gene site on the BCR/ABL mRNA were selected according to Max-Planck-Institute (MPI) and rational siRNA design rules, the secondary structure of the candidate targeted mRNA was predicted, the relevant thermodynamic parameters were analyzed, and the targeted gene sequences were compared with BLAST to eliminate any sequences with significant homology. Inhibition of proliferation was evaluated by MTT assay and colony-formation inhibiting test. Apoptosis was determined by flow cytometry (FCM) and the morphology of apoptotic cells was identified by Giemsa-Wright staining. Western blotting was used to analyze the expression of BCR/ABL fusion protein in K562 cells after siRNA treatment.

RESULTS

The mRNA local secondary structure calculated by RNA structure software, and the optimal design of specific siRNA were contributed by bioinformatics rules. Five sequences of BCR/ABL siRNAs were designed and synthesized in vitro. Three sequences, siRNA1384, siRNA1276 and siRNA1786, which showed the most effective inhibition of K562 cell growth, were identified among the five candidate siRNAs, with a cell proliferative inhibitory rate nearly 50% after exposure to 12.5 nmol/L~50 nmol/L siRNA1384 for 24,48 and 72 hours. The 50% inhibitory concentrations (IC50) of siRNA1384, siRNA1276 and siRNA1786 for 24 hours were 46.6 nmol/L, 59.3 nmol/L and 62.6 nmol/L, respectively, and 65.668 nmol/L, 76.6 nmol/L, 74.4 nmol/L for 72 hours. The colony-formation inhibiting test also indicated that, compared with control, cell growth of siRNA treated group was inhibited. FCM results showed that the rate of cell apoptosis increased 24 hours after transfecting siRNA. The results of annexinV/PI staining indicated that the rate of apoptosis imcreased (1.53%, 15.3%, 64.5%, 57.5% and 21.5%) following treamtne with siRNAs (siRNA34, siRNA372, siRNA1384, siRNA1276 and siRNA1786). Morphological analysis showed td typical morphologic changes of apoptosis such as shrunken, fragmentation nucleus as well as "apoptotic bodies" after K562 cell exposure to siRNA. Western blot analysis showed that BCR/ABL protein was reduced sharply after a single dose of 50 nmol/L siRNA transfection.

CONCLUSIONS

Proliferation of K562 cells was remarkbly inhibited by siRNAs (siRNA1384, siRNA1276 and siRNA1786) in a concentration-dependent manner in vitro, with effective induction of apoptosis at a concentration of 50 nmol/L. One anti-leukemia mechanism in K562 cells appeared that BCR/ABL targeted protein was highly down-regulated. The siRNAs (siRNA1384, siRNA1276 and siRNA1786) may prove valuable in the treatment of CML.

Implantable hydrogel embedded dark-gold nanoswitch as a theranostic probe to sense and overcome cancer multidrug resistance

Multidrug resistance (MDR) in cancer cells is a substantial limitation to the success of chemotherapy. Here, we describe facile means to overcome resistance by silencing the multidrug resistance protein 1 (MRP1), before chemotherapeutic drug delivery in vivo with a single local application. Our platform contains hydrogel embedded with dark-gold nanoparticles modified with 5-fluorouracil (5-FU)-intercalated nanobeacons that serve as an ON/OFF molecular nanoswitch triggered by the increased MRP1 expression within the tumor tissue microenvironment. This nanoswitch can sense and overcome MDR prior to local drug release. The nanobeacons comprise a 5-FU intercalated DNA hairpin, which is labeled with a near-infrared (NIR) dye and a dark-quencher. The nanobeacons are designed to open and release the intercalated drug only upon hybridization of the DNA hairpin to a complementary target, an event that restores fluorescence emission due to nanobeacons conformational reorganization. Despite the cross-resistance to 5-FU, more than 90% tumor reduction is achieved in vivo in a triple-negative breast cancer model following 80% MRP1 silencing compared with the continuous tumor growth following only drug or nanobeacon administration. Our approach can be applied to reverse cross-resistance to other chemotherapeutic drugs and restore treatment efficacy. As a universal nanotheranostic probe, this platform can pave the way to early cancer detection and treatment.

Etoposide incorporated into camel milk phospholipids liposomes shows increased activity against fibrosarcoma in a mouse model

Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

Vemurafenib resistance selects for highly malignant brain and lung-metastasizing melanoma cells

V600E being the most common mutation in BRAF, leads to constitutive activation of the MAPK signaling pathway. The majority of V600E BRAF positive melanoma patients treated with the BRAF inhibitor vemurafenib showed initial good clinical responses but relapsed due to acquired resistance to the drug. The aim of the present study was to identify possible biomarkers associated with the emergence of drug resistant melanoma cells. To this end we analyzed the differential gene expression of vemurafenib-sensitive and vemurafenib resistant brain and lung metastasizing melanoma cells. The major finding of this study is that the in vitro induction of vemurafenib resistance in melanoma cells is associated with an increased malignancy phenotype of these cells. Resistant cells expressed higher levels of genes coding for cancer stem cell markers (JARID1B, CD271 and Fibronectin) as well as genes involved in drug resistance (ABCG2), cell invasion and promotion of metastasis (MMP-1 and MMP-2). We also showed that drug-resistant melanoma cells adhere better to and transmigrate more efficiently through lung endothelial cells than drug-sensitive cells. The former cells also alter their microenvironment in a different manner from that of drug-sensitive cells. Biomarkers and molecular mechanisms associated with drug resistance may serve as targets for therapy of drug-resistant cancer.

WITHDRAWN: Effective suppression of Rituximab-resistant B-cell lymphoma by a comb-like anti-CD20 mAb nanocluster

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Toward a magic or imaginary bullet? Ligands for drug targeting to cancer cells: principles, hopes, and challenges

There are many problems directly correlated with the systemic administration of drugs and how they reach their target site. Targeting promises to be a hopeful strategy as an improved means of drug delivery, with reduced toxicity and minimal adverse side effects. Targeting exploits the high affinity of cell-surface-targeted ligands, either directly or as carriers for a drug, for specific retention and uptake by the targeted diseased cells. One of the most important parameters which should be taken into consideration in the selection of an appropriate ligand for targeting is the binding affinity (K D). In this review we focus on the importance of binding affinities of monoclonal antibodies, antibody derivatives, peptides, aptamers, DARPins, and small targeting molecules in the process of selection of the most suitable ligand for targeting of nanoparticles. In order to provide a critical comparison between these various options, we have also assessed each technology format across a range of parameters such as molecular size, immunogenicity, costs of production, clinical profiles, and examples of the level of selectivity and toxicity of each. Wherever possible, we have also assessed how incorporating such a targeted approach compares with, or is superior to, original treatments.

Self-assembled core-shell nanoparticles for combined chemotherapy and photodynamic therapy of resistant head and neck cancers

Combination therapy enhances anticancer efficacy of both drugs via synergistic effects. We report here nanoscale coordination polymer (NCP)-based core-shell nanoparticles carrying high payloads of cisplatin and the photosensitizer pyrolipid, NCP@pyrolipid, for combined chemotherapy and photodynamic therapy (PDT). NCP@pyrolipid releases cisplatin and pyrolipid in a triggered manner to synergistically induce cancer cell apoptosis and necrosis. In vivo pharmacokinetic and biodistribution studies in mice show prolonged blood circulation times, low uptake in normal organs, and high tumor accumulation of cisplatin and pyrolipid. Compared to monotherapy, NCP@pyrolipid shows superior potency and efficacy in tumor regression (83% reduction in tumor volume) at low drug doses in the cisplatin-resistant human head and neck cancer SQ20B xenograft murine model. We elucidated the in vitro/vivo fate of the lipid layer and its implications on the mechanisms of actions. This study suggests multifunctional NCP core-shell nanoparticles as a versatile and effective drug delivery system for potential translation to the clinic.

The redox-active nanomaterial toolbox for cancer therapy

Advances in nanomaterials science contributed in recent years to develop new devices and systems in the micro and nanoscale for improving the diagnosis and treatment of cancer. Substantial evidences associate cancer cells and tumor microenvironment with reactive oxygen species (ROS), while conventional cancer treatments and particularly radiotherapy, are often mediated by ROS increase. However, the poor selectivity and the toxicity of these therapies encourage researchers to focus efforts in order to enhance delivery and to decrease side effects. Thus, the development of redox-active nanomaterials is an interesting approach to improve selectivity and outcome of cancer treatments. Herein, we describe an overview of recent advances in redox nanomaterials in the context of current and emerging strategies for cancer therapy based on ROS modulation.

Enhanced therapeutic efficacy and cytotoxicity of doxorubicin-loaded vitamin E – Pluronic micelles against liver cancer

In this study, a new polymeric micelle delivery system was developed to increase the therapeutic efficacy of doxorubicin (DOX) and to reduce its associated side effects.

Targeted and controlled drug delivery using a temperature and ultra-violet responsive liposome with excellent breast cancer suppressing ability

Drug delivery systems (DDS) with favorable serum stability, high intra-tumor accumulation and tumor specific drug release are highly desired for promoting chemotherapeutic efficacy.

Rational design and fabrication of a cancer-targeted chitosan nanocarrier to enhance selective cellular uptake and anticancer efficacy of selenocystine

A cancer-targeted chitosan nanocarrier has been rationally designed to enhance the selective cellular uptake and anticancer efficacy of selenocystine.

Advances in Anticancer Protein Delivery Using Micro-/ Nanoparticles

Proteins exhibiting anticancer activities, especially those capable of discriminately killing cancer cells, have attracted increasing interest in developing protein-based anticancer therapeutics. This progress report surveys recent advances in delivering anticancer proteins directly to tumor tissue for inducing apoptosis/necrosis or indirectly to antigen presenting cells for provoking immune responses. Protein delivery carriers such as inorganic particles, lipid particles, polymeric particles, DNA/protein based biomacromolecular particles as well as cell based carriers are reviewed with comments on their advantages and limitations. Future challenges and opportunities are also discussed.

Review of natural compounds for potential skin cancer treatment

Most anti-cancer drugs are derived from natural resources such as marine, microbial and botanical sources. Cutaneous malignant melanoma is the most aggressive form of skin cancer, with a high mortality rate. Various treatments for malignant melanoma are available, but due to the development of multi-drug resistance, current or emerging chemotherapies have a relatively low success rates. This emphasizes the importance of discovering new compounds that are both safe and effective against melanoma. In vitro testing of melanoma cell lines and murine melanoma models offers the opportunity for identifying mechanisms of action of plant derived compounds and extracts. Common anti-melanoma effects of natural compounds include potentiating apoptosis, inhibiting cell proliferation and inhibiting metastasis. There are different mechanisms and pathways responsible for anti-melanoma actions of medicinal compounds such as promotion of caspase activity, inhibition of angiogenesis and inhibition of the effects of tumor promoting proteins such as PI3-K, Bcl-2, STAT3 and MMPs. This review thus aims at providing an overview of anti-cancer compounds, derived from natural sources, that are currently used in cancer chemotherapies, or that have been reported to show anti-melanoma, or anti-skin cancer activities. Phytochemicals that are discussed in this review include flavonoids, carotenoids, terpenoids, vitamins, sulforaphane, some polyphenols and crude plant extracts.

Liposomal nitrooxy-doxorubicin: one step over caelyx in drug-resistant human cancer cells

In this work we prepared and characterized two liposomal formulations of a semisynthetic nitric oxide (NO)-releasing doxorubicin (Dox), called nitrooxy-Dox (NitDox), which we previously demonstrated to be cytotoxic in Dox-resistant human colon cancer cells. Liposomes with 38.2% (Lip A) and 19.1% (Lip B) cholesterol were synthesized: both formulations had similar size and zeta potential values and caused the same intracellular distribution of free NitDox, but Lip B accumulated and released NitDox more efficiently. In Dox-resistant human colon cancer cells, Lip A and Lip B exhibited a more favorable kinetics of drug uptake and NO release, and a stronger cytotoxicity than Dox and free NitDox. While Caelyx, one of the liposomal Dox formulations approved for breast and ovary tumors treatment, was ineffective in Dox-resistant breast/ovary cancer cells, Lip B, and to a lesser extent Lip A, still exerted a significant cytotoxicity in these cells. This event was accompanied in parallel by a higher release of NO, which caused nitration of P-glycoprotein (Pgp) and multidrug resistance related protein 1 (MRP1), two transporters involved in Dox efflux, and impaired their pump activity. By doing so, the efflux kinetics of Dox after treatment with Lip B was markedly slowed down and the intracellular accumulation of Dox was increased in breast and ovary drug-resistant cells. We propose these liposomal formulations of NitDox as new tools with a specific indication for tumors overexpressing Pgp and MRP1.

Cytochrome c end-capped mesoporous silica nanoparticles as redox-responsive drug delivery vehicles for liver tumor-targeted triplex therapy in vitro and in vivo

To develop carriers for efficient anti-cancer drug delivery with reduced side effects, a biocompatible and redox-responsive nanocontainer based on mesoporous silica nanoparticles (MSNs) for tumor-targeted triplex therapy was reported in this study. The nanocontainer was fabricated by immobilizing cytochrome c (CytC) onto the MSNs as sealing agent via intermediate linkers of disulfide bonds for redox-responsive intracellular drug delivery. AS1411 aptamer was further tailored onto MSNs for cell/tumor targeting. The successful construction of redox- responsive MSNs was confirmed by BET/BJH analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermogravimetric analysis (TGA), respectively. Detailed investigations demonstrated that anticancer drug of doxorubicin (DOX) loaded nanocontainer could be triggered by reductant (e.g. glutathione) within cellular microenvironment and release DOX to induce tumor cell apoptosis in vitro. More importantly, the nanocontainer displayed great potential for tumor targeting and achieved triplex therapy effects on the tumor inhibition in vivo through the loading DOX, gatekeeper of CytC and AS1411 aptamer, which were reflected by the change of tumor size, TUNEL staining and HE staining assays.

Nanotechnology applications in diagnosis and treatment of metastasis

The lethality of solid tumors is in large part dependent on their ability to metastasize through hematologic and lymphatic transport pathways. The dissemination of cancer cells from the primary tumor to undergo transport, their ability to survive in transit and then to subsequently form metastatic colonies, is facilitated by a complex concert of signaling pathways and cell–cell and cell–matrix interactions. Elucidating these mechanistic components is highly valuable to guide the development of technologies for efficiently detecting and treating metastasis. To this end, in recent years nanotechnology approaches have provided several unique detection, characterization and treatment strategies. The current article will review these approaches to discuss their promise and challenges, specifically in metastatic cancer, above and beyond the usual nanomedicine applications in cancer therapy.

Nanoparticle-mediated drug delivery system for cardiovascular disease

Administration of drugs and other therapeutic agents has been the central strategy of contemporary medicine for cardiovascular disease. The use of a drug delivery system (DDS) is always demanded to enhance the efficacy and safety of therapeutic agents, and improve the signal-to-noise ratio of imaging agents. Nano-scale materials modify in vivo drug kinetics, depending on (patho)physiological mechanisms such as vascular permeability and incorporation by the mononuclear phagocyte system, which constitute 'passive-targeting' properties of nano-DDS. By contrast, an 'active-targeting' strategy employs a specific targeting structure on nano-DDS, which binds to the target molecule that is specific for a certain disease process, such as tumor specific antigens and the induction of adhesion molecules. In this review, we summarize recent studies that applied nano-DDS for the diagnosis and treatment of cardiovascular disease, especially focusing on atherosclerosis and myocardial ischemia-reperfusion (IR) injury. Pathophysiological changes in atherosclerosis and myocardial IR injury are successfully targeted by nano-DDS and preclinical studies in animals showed positive effects of nano-DDS enhancing efficacy and reducing adverse effects. The development of nano-DDS in clinical medicine is keenly being awaited.

Targeted nanoparticles for pediatric leukemia therapy

The two major forms of leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), account for about one-third of the malignancies diagnosed in children. Despite the marked successes in ALL and AML treatment, concerns remain regarding the occurrence of resistant disease in subsets of patients, the residual effects of therapy that often persist for decades beyond the cessation of treatment. Therefore, new approaches are needed to reduce or to avoid off target toxicities, associated with chemotherapy and their long-term residual effects. Recently, nanotechnology has been employed to enhance cancer therapy, via improving the bioavailability and therapeutic efficacy of anti-cancer agents. While in the last several years, numerous review articles appeared detailing the size, composition, assembly, and performance evaluation of different types of drug carrying nanoparticles, the description and evaluation of lipoprotein-based drug carriers have been conspicuously absent from most of these major reviews. The current review focuses on such information regarding nanoparticles with an emphasis on high density lipoprotein-based drug delivery systems to examine their potential role(s) in the enhanced treatment of children with leukemia.

Potentials and emerging trends in nanopharmacology

Nanopharmacology is a relatively newer branch of pharmacology which investigates interaction of a nanomedicine with living systems at the nanoscale level. Modern medicine is increasingly concerned with various surface modified nanocarriers, such as dendrimers, nanoparticles, carbon based nanomaterials, polymer-drug nanoconjugates, etc., which have immense therapeutic potential by target specific drug delivery, using nanoscaffolding and nanocontainers, owing to the specific physical, chemical and biological properties of these moieties that is related to their nanoscale size range. Nanopharmacology could have potential medical and pharmaceutical benefits via applications of nanotechnology in the delivery of therapeutic and diagnostic agents. Nanomaterials may be expected to find application in the cardiovascular, as well as, renal arena, in the near future.

Undecylprodigiosin conjugated monodisperse gold nanoparticles efficiently cause apoptosis in colon cancer cells in vitro

Bacterial pigment undecylprodigiosin was conjugated to monodisperse gold nanoparticles, resulting in improved stability and cytotoxicity against colon cancer cells.