Sustained targeting of Bcr–Abl + leukemia cells by synergistic action of dual drug loaded nanoparticles and its implication for leukemia therapy

Organic Nanoparticles as Drug Delivery Systems and Their Potential Role in the Treatment of Chronic Myeloid Leukemia

Chronic myeloid leukemia is a myeloproliferative neoplasm that occurs more prominently in the older population, with a peak incidence at ages 45 to 85 years and a median age at diagnosis of 65 years. This disease comprises roughly 15% of all leukemias in adults. It is a clonal stem cell disorder of myeloid cells characterized by the presence of t(9;22) chromosomal translocation, also known as the Philadelphia chromosome, or its byproducts BCR-ABL fusion protein/messenger RNA, leading to the expression of a protein with enhanced tyrosine kinase activity. This fusion protein has become the main therapeutic target in chronic myeloid leukemia therapy, with imatinib displaying superior antileukemic effects, placing it at the forefront of current treatment protocols and displaying great efficacy. Alternatively, nanomedicine and employing nanoparticles as drug delivery systems may represent new approaches in future anticancer therapy. This review focuses primarily on the use of organic nanoparticles aimed at chronic myeloid leukemia therapy in both in vitro and in vivo settings, by going through a thorough survey of published literature. After a brief introduction on the pathogenesis of chronic myeloid leukemia, a description of conventional, first- and second-line, treatment modalities of chronic myeloid leukemia is presented. Finally, some of the general applications of nanostrategies in medicine are presented, with a detailed focus on organic nanocarriers and their constituents used in chronic myeloid leukemia treatment from the literature.

Cholesterol grafted cationic lipopolymers: Potential siRNA carriers for selective chronic myeloid leukemia therapy

Synthetic siRNA technology has emerged as a promising approach for molecular therapy of cancer but, despite its potential for post-transcriptional gene silencing, there is an urgent need to develop efficient delivery systems particularly for difficult-to-transfect, anchorage-independent cells. In this study, we designed highly hydrophobic cationic lipopolymers by grafting cholesterol (Chol) onto low-molecular weight (0.6, 1.2, and 2.0 kDa) polyethylenimines (PEIs) to enable specific siRNA therapy to chronic myeloid leukemia (CML) cells. The siRNA binding by PEI-Chol led to nano-sized (100-200 nm diameter) polyplexes with enhanced ζ-potential (+20 to +35 mV) and ability to protect the loaded siRNA completely in fresh serum. The siRNA delivery to CML (K562) cells was proportional to degree of substitution and, unexpectedly, inversely proportional to molecular size of the polymeric backbone. Chol grafting with as little as ~1.0 Chol/PEI on 0.6 and 1.2 kDa PEIs enabled silencing of the reporter Green Fluorescent Protein gene as well as the endogenous BCR-Abl oncogene in K562 cells. The PEI-Chol mediated delivery of siRNAs specific for BCR-Abl and KSP genes significantly arrested the growth the cells which was significantly reflected in colony formation potency of K562 cells. BCR-Able siRNA mediated therapeutic efficacy was also observed in significantly increased caspase activity and apoptosis of K562 cells. Thus, Chol-grafted low-molecular weight PEIs appear to be unique siRNA carriers to realize the molecular therapy in CML cells.

A bio-responsive 6-mercaptopurine/doxorubicin based "Click Chemistry" polymeric prodrug for cancer therapy

A novel bio-responsive co-delivery system based on Poly(DEA)-b-Poly(ABMA-co-OEGMA) (PDPAO, prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization) copolymers was constructed for enhanced cellular internalization and effective combination therapy. Reduction-sensitive 6-mercaptopurine (6MP) based prodrug and pH-sensitive doxorubicin (DOX) based prodrug were grafted onto PDPAO by an azide-alkyne "Click Chemistry" reaction to acquire a pH/reduction-sensitive polymeric prodrug (PDPAO@imine-DOX/cis-6MP), which was able to self-aggregate to form polymeric micelles (M(DOX/6MP)) with an average particle size of 116 ± 2 nm in the water. The resultant micelles could maintain a stable sphere structure and show stability with a small particles' dispersion index in the blood. Importantly, it has been observed that the pH-sensitive surface charge-conversion accompanied pH-triggered DOX release in the biomimetic extracellular acidic environment of tumor tissue and a rapid dual-drug release triggered by pH and GSH in the intracellular environment. The in vitro evaluation of micelles on human cervical cancer (HeLa) and human promyelocytic leukemia (HL-60) cells showed an enhanced cellular uptake because of charge-conversion and exhibited a higher cell-killing performance. Moreover, the graft ratio of DOX and 6MP showed the ability to adjust the cytotoxicity; the micelles with a graft ratio of 2: 1 (M(DOX₂/6MP)) displayed the higher cellular inhibition on either HeLa (combination index (CI) = 0.62) or HL-60 (CI = 0.35) cells. Overall, this novel dual-drug-conjugated delivery system might have important potential applications for combination therapy of cancer.

Dual-drug delivery based charge-conversional polymeric micelles for enhanced cellular uptake and combination therapy

We herein report on the synthesis and characterization of a dual-drug conjugated prodrug, and the self-assembled micelles showed a charge-conversion behavior and synergistic effectin vitro.

Preventive Effect of Curcumin Against Chemotherapy-Induced Side-Effects

Cancer is still a severe threat to the health of people worldwide. Chemotherapy is one of main therapeutic approaches to combat cancer. However, chemotherapy only has a limited success with severe side effects, especially causing damage to normal tissues such as bone marrow, gastrointestine, heart, liver, renal, neuron, and auditory tissues, etc. The side-effects limit clinical outcome of chemotherapy and lower patients’ quality of life, and even make many patients discontinue the chemotherapy. Thus, there is a need to explore effective adjuvant strategies to prevent and reduce the chemotherapy-induced side effects. Naturally occurring products provide a rich source for exploring effective adjuvant agents to prevent and reduce the side effects in anticancer chemotherapy. Curcumin is an active compound from natural plant Curcuma longa L., which is widely used as a coloring and flavoring agent in food industry and a herbal medicine in Asian countries for thousands of years to treat vomiting, headache, diarrhea, etc. Modern pharmacological studies have revealed that curcumin has strong antioxidative, anti-microbial, anti-inflammatory and anticancer activities. Growing evidence shows that curcumin is able to prevent carcinogenesis, sensitize cancer cells to chemotherapy, and protect normal cells from chemotherapy-induced damages. In the present article, we review the preventive effect of curcumin against chemotherapy-induced myelosuppression, gastrointestinal toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, ototoxicity, and genotoxicity, and discuss its action mechanisms.

Targeting of EGFR, VEGFR2, and Akt by Engineered Dual Drug Encapsulated Mesoporous Silica-Gold Nanoclusters Sensitizes Tamoxifen-Resistant Breast Cancer

Tamoxifen administration enhanced overall disease-free survival and diminished mortality rates in cancer patients. However, patients with breast cancer often fail to respond for tamoxifen therapy due to the development of a drug-resistant phenotype. Functional analysis and molecular studies suggest that protein mutation and dysregulation of survival signaling molecules such as epidermal growth factor receptor, vascular endothelial growth factor receptor 2, and Akt contribute to tamoxifen resistance. Various strategies, including combinatorial therapies, show chemosensitize tamoxifen-resistant cancers. Based on chemotoxicity issues, researchers are actively investigating alternative therapeutic strategies. In the current study, we fabricate a mesoporous silica gold cluster nanodrug delivery system that displays exceptional tumor-targeting capability, thus promoting accretion of drug indices at the tumor site. We employ dual drugs, ZD6474, and epigallocatechin gallate (EGCG) that inhibit EGFR2, VEGFR2, and Akt signaling pathways since changes in these signaling pathways confer tamoxifen resistance in MCF 7 and T-47D cells. Mesoporous silica gold cluster nanodrug delivery of ZD6474 and EGCG sensitize tamoxifen-resistant cells to apoptosis. Western and immune-histochemical analyses confirmed the apoptotic inducing properties of the nanoformulation. Overall, results with these silica gold nanoclusters suggest that they may be a potent nanoformulation against chemoresistant cancers.

Platinum covalent shell cross-linked micelles designed to deliver doxorubicin for synergistic combination cancer therapy

The preparation of polymer therapeutics capable of controlled release of multiple chemotherapeutic drugs has remained a tough problem in synergistic combination cancer therapy. Herein, a novel dual-drug co-delivery system carrying doxorubicin (DOX) and platinum(IV) (Pt[IV]) was developed. An amphiphilic diblock copolymer, PCL-b-P(OEGMA-co-AzPMA), was synthesized and used as a nanoscale drug carrier in which DOX and Pt(IV) could be packaged together. The copolymers were shell cross-linked by Pt(IV) prodrug via a click reaction. Studies on the in vitro drug release and cellular uptake of the dual-drug co-delivery system showed that the micelles were effectively taken up by the cells and simultaneously released drugs in the cells. Futhermore, the co-delivery polymer nanoparticles caused much higher cell death in HeLa and A357 tumor cells than either the free drugs or single-drug-loaded micelles at the same dosage, exhibiting a synergistic combination of DOX and Pt(IV). The results obtained with the shell cross-linked micelles based on an anticancer drug used as a cross-linking linkage suggested a promising application of the micelles for multidrug delivery in combination cancer therapy.

NKCT1 (purified Naja kaouthia protein toxin) conjugated gold nanoparticles induced Akt/mTOR inactivation mediated autophagic and caspase 3 activated apoptotic cell death in leukemic cell

BACKGROUND

Gold nanoparticle (GNP) and snake venom protein toxin NKCT1 was conjugated as stated earlier (Bhowmik et al., 2013). The aim of this study was to explore the caspase dependent apoptotic pathway and autophagy inducing ability of gold nanoparticles tagged snake venom protein toxin NKCT1 (GNP-NKCT1) in human leukemic U937 and K562 cell line.

METHODS

GNP-NKCT1 induced apoptosis in U937 and K562 cell line were assessed through mitochondrial membrane potential assay, ROS generation assay, caspase 3 pathways and western blotting. GNP-NKCT1 induced autophagic pathway was detected through Akt, mTOR and PI3K expression by western blotting. Autophagic cell death also checked after addition of caspase 3 inhibitor and which also reconfirmed by western blotting of autophagic marker protein, lysosomal staining.

RESULTS

Loss of mitochondrial membrane potential was occurred in both the leukemic cell line after induction by GNP-NKCT1 and treatment of which also exhibited high ROS generation. Caspase 3 expression of cell was also increased. With caspase 3 inhibitor, GNP-NKCT1 downregulated PI3K/Akt and mTOR expression and thus undergoing autophagic cell death. Lysosomal staining confirmed lysosomal enzyme involvement in the autophagic response. Up regulation of Atg 3, Atg12, Beclin 1, LC3-II protein and BIF-1 and down regulation of Atg4B were also showed by blotting.

CONCLUSION

The results demonstrated that conjugation of Gold nanoparticles with NKCT1 could induce an alternate cell death pathway other than apoptosis in the form of autophagy in leukemic cell.

GENERAL SIGNIFICANCE

This study might provide the understanding area of chemotherapeutic drug development from natural resources like snake venoms.

Sequential release of drugs from hollow manganese ferrite nanocarriers for breast cancer therapy

Single drug therapies for cancer are often ineffective and may not provide long term clinical benefits.

Toxic effects induced by curcumin in human astrocytoma cell lines

OBJECTIVE

The objective of this study was to describe the toxicity induced by curcumin in human astrocytoma cell lines.

METHODS

The effects induced by curcumin, at 100 µM for 24 h, were evaluated in four astrocytoma cell lines using crystal violet assay and through the evaluation of morphological and ultrastructural changes by electron microscopy. Also, the results of vital staining with acridine orange and propidium iodide for acidic vesicles and apoptotic bodies were analyzed and the expression of the Beclin1 gene was assessed by RT-PCR.

RESULTS

The cells treated with curcumin at 100 µM induced an inhibitory concentration50 of viability with morphological changes characterized by a progressive increase in large, non-acidic vesicles devoid of cytoplasmic components and organelles, but that conserved the cell nuclei. No DNA breakage was observed. The astrocytoma cells showed no apoptosis, necrosis or autophagy. Expression of BECLIN1 was not induced (p < 0.05) by curcumin in the astrocytoma cells.

CONCLUSIONS

Curcumin at 100 µm induced a new type of death cell in astrocytoma cell lines.

Solidified self-nanoemulsifying formulation for oral delivery of combinatorial therapeutic regimen: part II in vivo pharmacokinetics, antitumor efficacy and hepatotoxicity

PURPOSE

The present work focuses on the in vivo evaluation of tamoxifen and quercetin combination loaded into solid self-nanoemulsifying drug delivery system (s-Tmx-QT-SNEDDS).

METHODS

Lyophilization was employed to prepare s-Tmx-QT-SNEDDS using Aerosil 200 as carrier. The developed formulation was evaluated for in vitro cell cytotoxicity, in vivo pharmacokinetics, antitumor efficacy and toxicity studies.

RESULTS

In vivo pharmacokinetics revealed ~8-fold and ~4-fold increase in oral bioavailability of tamoxifen and quercetin, respectively as compared to free counterparts. s-Tmx-QT-SNEDDS exhibited significantly higher cell cytotoxicity, as compared to free drug combination revealing ~32-fold and ~22-fold higher dose reduction index for tamoxifen and quercetin, respectively estimated using median effect dose analysis. s-Tmx-QT-SNEDDS could suppress tumor growth in DMBA induced tumor bearing animals by ~80% in contrast to ~35% observed with tamoxifen citrate. The significant appreciation in antitumor efficacy was further supported by normalized levels of tumor angiogenesis markers (MMP-2 and MMP-9). Finally, complete obliteration in tamoxifen induced hepatotoxicity was observed upon administration of developed formulation in contrast to that of clinically available tamoxifen citrate when measured as function of hepatotoxicity markers and histopathological changes.

CONCLUSIONS

In nutshell, co-encapsulation of quercetin with tamoxifen in solid SNEDDS poses great potential in improving the therapeutic efficacy and safety of tamoxifen.

Enhanced accumulation of curcumin and temozolomide loaded magnetic nanoparticles executes profound cytotoxic effect in glioblastoma spheroid model

Glioblastomas (GBMs) are highly lethal primary brain tumours. Treatment of these malignant gliomas remains ineffective as these are extremely resistant to chemotherapeutic applications. Furthermore, combination therapy for cancer treatment is becoming more popular because it generates synergistic anticancer effects, by reducing individual drug-related toxicity and associated side effects. Currently, magnetic nanoparticles (MNPs) based drug delivery system has attracted much more attention owing to its intrinsic magnetic properties and drug loading capacity. In the present study, MNPs based drug delivery approach for co-delivering of potent chemotherapeutic drugs such as Curcumin (herbal drug) and Temozolomide (DNA methylating agent) has been implemented. The dual drug loaded MNPs formulations were evaluated in two-dimensional (2-D) monolayer culture and three-dimensional (3-D) tumour spheroid culture of T-98G cells for understanding the therapeutic discrepancy. The dual drug loaded MNPs formulations demonstrated higher cytotoxic effect than single drug loaded MNPs formulations as compared to their corresponding native drugs in 2-D and 3-D culture. The combination index (CI) analysis revealed synergistic mode of action of dual drug loaded MNPs formulations, which was further confirmed by cell death induction assay mediated by acridine orange (AO)/propidium iodide (PI) staining, illustrating higher efficacy of the formulation towards GBM therapy.

Emerging role of nanocarriers to increase the solubility and bioavailability of curcumin

INTRODUCTION

Curcumin is a safe, affordable and natural bioactive molecule of turmeric (Curcuma longa). It has gained considerable attention in recent years for its multiple pharmacological activities. However, its optimum pharmaceutical potential has been limited by its lack of aqueous solubility and poor bioavailability. To mitigate the above limitations, recently various nanostructured water-soluble delivery systems were developed to increase the solubility and bioavailability of curcumin.

AREAS COVERED

Major reasons contributing to the low bioavailability of curcumin appear to be owing to its poor solubility, low absorption, rapid metabolism and rapid systemic elimination. The present review summarizes the strategies using curcumin in various nanocarrier delivery systems to overcome poor solubility and inconsistent bioavailability of curcumin and describes the current status and challenges for the future.

EXPERT OPINION

The development of various drug delivery systems to deliver curcumin will certainly provide a step up towards augmenting the therapeutic activity of curcumin thereby increasing the solubility and bioavailability of curcumin. However, the future of such delivery technology will be highly dependent on the development of safe, non-toxic and non-immunogenic nanocarriers.

Antiglioma activity of curcumin-loaded lipid nanoparticles and its enhanced bioavailability in brain tissue for effective glioblastoma therapy

Glioblastoma, the most aggressive form of brain and central nervous system tumours, is characterized by high rates proliferation, migration and invasion. The major road block in the delivery of drugs to the brain is the blood-brain barrier, along with the expression of various multi-drug resistance (MDR) proteins that cause the efflux of a wide range of chemotherapeutic drugs. Curcumin, a herbal drug, is known to inhibit cellular proliferation, migration and invasion and induce apoptosis of glioma cells. It also has the potential to modulate MDR in glioma cells. However, the greatest challenge in the administration of curcumin stems from its low bioavailability and high rate of metabolism. To circumvent the above pitfalls of curcumin we have developed curcumin-loaded glyceryl monooleate (GMO) nanoparticles (NP) coated with the surfactant Pluronic F-68 and vitamin E D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) for brain delivery. We demonstrated that our curcumin-loaded NPs inhibit cellular proliferation, migration and invasion along with a higher percentage of cell cycle arrest and telomerase inhibition, thus leading to a greater percentage apoptotic cell death in glioma cells compared with native curcumin. An in vivo study demonstrated enhanced bioavailability of curcumin in blood serum and brain tissue when delivered by curcumin-loaded GMO NPs compared with native curcumin in a rat model. Thus, curcumin-loaded GMO NPs can be used as an effective delivery system to overcome the challenges of drug delivery to the brain, providing a new approach to glioblastoma therapy.

Nanotechnology-based combinational drug delivery: an emerging approach for cancer therapy

Combination therapy for the treatment of cancer is becoming more popular because it generates synergistic anticancer effects, reduces individual drug-related toxicity and suppresses multi-drug resistance through different mechanisms of action. In recent years, nanotechnology-based combination drug delivery to tumor tissues has emerged as an effective strategy by overcoming many biological, biophysical and biomedical barriers that the body stages against successful delivery of anticancer drugs. The sustained, controlled and targeted delivery of chemotherapeutic drugs in a combination approach enhanced therapeutic anticancer effects with reduced drug-associated side effects. In this article, we have reviewed the scope of various nanotechnology-based combination drug delivery approaches and also summarized the current perspective and challenges facing the successful treatment of cancer.

Curcumin-loaded magnetic nanoparticles for breast cancer therapeutics and imaging applications

Background

The next generation magnetic nanoparticles (MNPs) with theranostic applications have attracted significant attention and will greatly improve nanomedicine in cancer therapeutics. Such novel MNP formulations must have ultra-low particle size, high inherent magnetic properties, effective imaging, drug targeting, and drug delivery properties. To achieve these characteristic properties, a curcumin-loaded MNP (MNP-CUR) formulation was developed.

Methods

MNPs were prepared by chemical precipitation method and loaded with curcumin (CUR) using diffusion method. The physicochemical properties of MNP-CUR were characterized using dynamic light scattering, transmission electron microscopy, and spectroscopy. The internalization of MNP-CUR was achieved after 6 hours incubation with MDA-MB-231 breast cancer cells. The anticancer potential was evaluated by a tetrazolium-based dye and colony formation assays. Further, to prove MNP-CUR results in superior therapeutic effects over CUR, the mitochondrial membrane potential integrity and reactive oxygen species generation were determined. Magnetic resonance imaging capability and magnetic targeting property were also evaluated.

Results

MNP-CUR exhibited individual particle grain size of ~9 nm and hydrodynamic average aggregative particle size of ~123 nm. Internalized MNP-CUR showed a preferential uptake in MDA-MB-231 cells in a concentration-dependent manner and demonstrated accumulation throughout the cell, which indicates that particles are not attached on the cell surface but internalized through endocytosis. MNP-CUR displayed strong anticancer properties compared to free CUR. MNP-CUR also amplified loss of potential integrity and generation of reactive oxygen species upon treatment compared to free CUR. Furthermore, MNP-CUR exhibited superior magnetic resonance imaging characteristics and significantly increased the targeting capability of CUR.

Conclusion

MNP-CUR exhibits potent anticancer activity along with imaging and magnetic targeting capabilities. This approach can be extended to preclinical and clinical use and may have importance in cancer treatment and cancer imaging in the future. Further, if these nanoparticles can functionalize with antibody/ligands, they will serve as novel platforms for multiple biomedical applications.

Long circulating lectin conjugated paclitaxel loaded magnetic nanoparticles: a new theranostic avenue for leukemia therapy

Amongst all leukemias, Bcr-Abl positive chronic myelogenous leukemia (CML) confers resistance to native drug due to multi drug resistance and also resistance to p53 and fas ligand pathways. In the present study, we have investigated the efficacy of microtubule stabilizing paclitaxel loaded magnetic nanoparticles (pac-MNPs) to ascertain its cytotoxic effect on Bcr-Abl positive K562 cells. For active targeted therapy, pac-MNPs were functionalized with lectin glycoprotein which resulted in higher cellular uptake and lower IC₅₀ value suggesting the efficacy of targeted delivery of paclitaxel. Both pac-MNPs and lectin conjugated pac-MNPs have a prolonged circulation time in serum suggesting increased bioavailability and therapeutics index of paclitaxel in vivo. Further, the molecular mechanism pertaining to pac-induced cytotoxicity was analyzed by studying the involvement of different apoptotic pathway proteins by immunoblotting and quantitative PCR. Our study revealed simultaneous activation of JNK pathway leading to Bcr-Abl instability and the extrinsic apoptotic pathway after pac-MNPs treatment in two Bcr-Abl positive cell lines. In addition, the MRI data suggested the potential application of MNPs as imaging agent. Thus our in vitro and in vivo results strongly suggested the pac-MNPs as a future prospective theranostic tool for leukemia therapy.