Transferrin-conjugated curcumin-loaded superparamagnetic iron oxide nanoparticles induce augmented cellular uptake and apoptosis in K562 cells

Intracellular delivery of anti-BCR/ABL antibody by PLGA nanoparticles suppresses the oncogenesis of chronic myeloid leukemia cells

BACKGROUND

The pathogenesis of chronic myeloid leukemia (CML) is the formation of the BCR/ABL protein, which is encoded by the bcr/abl fusion gene, possessing abnormal tyrosine kinase activity. Despite the wide application of tyrosine kinase inhibitors (TKIs) in CML treatment, TKIs drug resistance or intolerance limits their further usage in a subset of patients. Furthermore, TKIs inhibit the tyrosine kinase activity of the BCR/ABL oncoprotein while failing to eliminate the pathologenic oncoprotein. To develop alternative strategies for CML treatment using therapeutic antibodies, and to address the issue that antibodies cannot pass through cell membranes, we have established a novel intracellular delivery of anti-BCR/ABL antibodies, which serves as a prerequisite for CML therapy.

METHODS

Anti-BCR/ABL antibodies were encapsulated in poly(D, L-lactide-co-glycolide) nanoparticles (PLGA NPs) by a double emulsion method, and transferrin was labeled on the surface of the nanoparticles (Ab@Tf-Cou6-PLGA NPs). The characteristics of nanoparticles were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Cellular uptake of nanoparticles was measured by flow cytometry (FCM). The effect of nanoparticles on the apoptosis and proliferation of CML cells was testified by FCM and CCK-8 assay. In addition, the anti-cancer impact of nanoparticles was evaluated in mouse models of CML.

RESULTS

The results demonstrated that the Ab@Tf-Cou6-PLGA NPs functioned as an intracellular deliverer of antibodies, and exhibited an excellent effect on degrading BCR/ABL oncoprotein in CML cells via the Trim-Away pathway. Treatment with Ab@Tf-Cou6-PLGA NPs inhibited the proliferation and induced the apoptosis of CML cells in vitro as well as impaired the oncogenesis ability of CML cells in vivo.

CONCLUSIONS

In conclusion, our study indicated that this approach achieved safe and efficient intracellular delivery of antibodies and degraded BCR/ABL oncoprotein via the Trim-Away pathway, which provides a promising therapeutic strategy for CML patients, particularly those with TKI resistance.

A mechanistic study of the effect of transferrin conjugation on cytotoxicity of targeted liposomes

This study was performed to prepare 5-fluorouracil (5FU) containing targeted liposomes for the safety and efficacy enhancement. Liposomes were prepared using thin layer method and transferrin (Tf) was employed as the targeting ligand. Morphology of 5FU-loaded liposomes was assessed by transmission electron microscopy (TEM). The in vitro cytotoxicity was investigated via MTT assay on HT-29, CT26 and fibroblast cells. Mitochondrial membrane and cell death evaluations were also investigated. Resulted showed that the encapsulation efficiency (EE%) and particle size of the liposomes were 40.12% and 130 nm, respectively. TEM image implied that liposomes were spherical in shape. In cancer cells, targeted liposomes triggered the mitochondrial apoptotic pathway by lower production of reactive oxygen species (ROS) (63.58 vs 84.95 fluorescence intensity), reduced mitochondrial membrane potential and releasing of cytochrome c (68.66 vs 51.13 ng/mL). The results of this study indicated that Tf-targeted 5FU liposomes can be employed as promising nanocarrier for the delivery of drugs to cancer cells.

Transferrin targeted liposomal 5-fluorouracil induced apoptosis via mitochondria signaling pathway in cancer cells

The purpose of this study was to prepare transferrin (Tf) targeted liposomal 5-Fluorouracil (5FU) to improve the safety and efficacy of the drug. Liposomes were prepared using thin layer method. Morphology of liposomes was characterized by transmission electron microscopy (TEM) and their particle size was also determined. The in vitro cytotoxicity was investigated via MTT assay on HT-29 (as cancer cell) and fibroblast (as normal cell). Moreover, cytotoxicity mechanism of targeted liposomes was determined through the production of reactive oxygen species (ROS), mitochondrial membrane potential (∆Ψ_m) and release of cytochrome c. Results showed that encapsulation efficiency (EE%) was 58.66±0.58 and average size of liposomes was 107nm. Also, nano-particles were spherical as shown by TEM. MTT assay on HT-29 cells revealed the higher cytotoxic activity of targeted liposomes in comparison to free drug and non-targeted liposome. In contrast, comparing with cancer cells, targeted liposomes had no cytotoxic effect on normal cells. In addition, targeted liposomes induced apoptosis through activation of mitochondrial apoptosis pathways, as evidenced by decreased mitochondrial membrane potential and release of cytochrome c. Results of the study indicated that targeted liposomes would provide a potential strategy to treat colon cancer by inducing apoptosis via mitochondria signaling pathway with reducing dose of the drug and resulting fewer side-effects.

The Essential Medicinal Chemistry of Curcumin

Curcumin is a constituent (up to ∼5%) of the traditional medicine known as turmeric. Interest in the therapeutic use of turmeric and the relative ease of isolation of curcuminoids has led to their extensive investigation. Curcumin has recently been classified as both a PAINS (pan-assay interference compounds) and an IMPS (invalid metabolic panaceas) candidate. The likely false activity of curcumin in vitro and in vivo has resulted in >120 clinical trials of curcuminoids against several diseases. No double-blinded, placebo controlled clinical trial of curcumin has been successful. This manuscript reviews the essential medicinal chemistry of curcumin and provides evidence that curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead. On the basis of this in-depth evaluation, potential new directions for research on curcuminoids are discussed.

Curcumin induces apoptosis in human leukemic cell lines through an IFIT2-dependent pathway

Curcumin, the primary bioactive component isolated from turmeric, has been shown to possess variety of biologic functions including anti-cancer activity. However, molecular mechanisms in different cancer cells are various. In the present study, we demonstrated that curcumin induced G2/M cell cycle arrest and apoptosis by increasing the expression levels of cleaved caspase-3, cleaved PARP and decreasing the expression of BCL^-2 in U937 human leukemic cells but not in K562 cells. We found some interferon induced genes, especially interferon-induced protein with tetratricopeptide repeats 2 (IFIT2), were significantly upregulated when treated with curcumin in U937 cells by gene expression chip array, and further confirmed that the expression of IFIT2 was obviously higher in U937 than that in K562 cells by Western blot assay. In addition, inhibiting the expression of IFIT2 by shRNA in U937 rescued curcumin-induced apoptosis and exogenous overexpression of IFIT2 by lentiviral transduction or treating with IFNγ in K562 cells enhanced anti-cancer activity of curcumin. These results indicated for the first time that curcumin induced leukemic cell apoptosis via an IFIT2-dependent signaling pathways. The present study identified a novel mechanism underlying the antitumor effects of curcumin, and may provide a theoretical basis for curcumin combined with interferon in the cancer therapeutics.

Conformational control of human transferrin covalently anchored to carbon-coated iron nanoparticles in presence of a magnetic field

The control of the interactions of proteins with the support matrix plays a key role in medicine, drug delivery systems and diagnostics. Herein, we report that covalent anchoring of human transferrin to carbon-coated iron magnetic nanoparticles functionalized with carboxylic groups (Fe@C-COOH Nps) in the presence of magnetic field results in its conformational integrity and electroactivity. We have found that, the direct contact of human transferrin with Fe@C-COOH Nps does not lead to release of iron and in consequence to the irreversible conformational changes of the protein. Moreover, the examination of the direct electron transfer between Tf molecules from the conjugate and the electrode surface was possible. The quartz crystal microbalance with dissipation (QCM-D)- and thermogravimetric data (TGA) showed that under such conditions, in addition to a monolayer, an adlayer of the protein can be formed on Fe@C-COOH Nps at constant pH.

STATEMENT OF SIGNIFICANCE

To our best knowledge this is the first paper that reports on covalent anchoring of human transferrin (Tf) to carbon-coated iron magnetic nanoparticles functionalized with carboxylic groups (Fe@C-COOH Nps) in the presence of magnetic field, which results in its conformational integrity and electroactivity. We showed that it is possible to attach, without changing pH, more than one single layer of transferrin to the Fe@C-COOH Nps. This is a very rare phenomenon in the case of proteins. We proved, using various experimental techniques, that the proposed methodology does not lead to release of iron from Tf molecules, what was the major problem so far. We believe that this finding opens new possibilities in targeting drug delivery systems and medical diagnostics.

Curcumin as potential therapeutic natural product: a nanobiotechnological perspective

OBJECTIVES

Nanotechnology-based drug delivery systems can resolve the poor bioavailability issue allied with curcumin. The therapeutic potential of curcumin can be enhanced by making nanocomposite preparation of curcumin with metal oxide nanoparticles, poly lactic-co-glycolic acid (PLGA) nanoparticles and solid lipid nanoparticles that increases its bioavailability in the tissue.

KEY FINDINGS

Curcumin has manifold therapeutic effects which include antidiabetic, antihypertensive, anticancer, anti-inflammatory and antimicrobial properties. Curcumin can inhibit diabetes, heavy metal and stress-induced hypertension with its antioxidant, chelating and inhibitory effects on the pathways that lead to hypertension. Curcumin is an anticancer agent that can prevent abnormal cell proliferation. Nanocurcumin is an improved form of curcumin with enhanced therapeutic properties due to improved delivery to the diseased tissue, better internalization and reduced systemic elimination.

SUMMARY

Curcumin has multiple pharmacologic effects, but its poor bioavailability reduces its therapeutic effects. By conjugating curcumin to metal oxide nanoparticles or encapsulation in lipid nanoparticles, dendrimers, nanogels and polymeric nanoparticles, the water solubility and bioavailability of curcumin can be improved and thus increase its pharmacological effectiveness.

Self-assembled Targeting of Cancer Cells by Iron(III)-doped, Silica Nanoparticles

Iron(III)-doped silica nanoshells are shown to possess an in vitro cell-receptor mediated targeting functionality for endocytosis. Compared to plain silica nanoparticles, iron enriched ones are shown to be target-specific, a property that makes them potentially better vehicles for applications, such as drug delivery and tumor imaging, by making them more selective and thereby reducing the nanoparticle dose. Iron(III) in the nanoshells can interact with endogenous transferrin, a serum protein found in mammalian cell culture media, which subsequently promotes transport of the nanoshells into cells by the transferrin receptor-mediated endocytosis pathway. The enhanced uptake of the iron(III)-doped nanoshells relative to undoped silica nanoshells by a transferrin receptor-mediated pathway was established using fluorescence and confocal microscopy in an epithelial breast cancer cell line. This process was also confirmed using fluorescence activated cell sorting (FACS) measurements that show competitive blocking of nanoparticle uptake by added holo-transferrin.

Curcumin and 5-fluorouracil-loaded, folate- and transferrin-decorated polymeric magnetic nanoformulation: a synergistic cancer therapeutic approach, accelerated by magnetic hyperthermia

The efficient targeting and therapeutic efficacy of a combination of drugs (curcumin and 5-Fluorouracil [5FU]) and magnetic nanoparticles encapsulated poly(D,L-lactic-co-glycolic acid) nanoparticles, functionalized with two cancer-specific ligands are discussed in our work. This multifunctional, highly specific nanoconjugate resulted in the superior uptake of nanoparticles by cancer cells. Upon magnetic hyperthermia, we could harness the advantages of incorporating magnetic nanoparticles that synergistically acted with the drugs to destroy cancer cells within a very short period of time. The remarkable multimodal efficacy attained by this therapeutic nanoformulation offers the potential for targeting, imaging, and treatment of cancer within a short period of time (120 minutes) by initiating early and late apoptosis.

Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells

Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.

Novel curcumin-loaded magnetic nanoparticles for pancreatic cancer treatment

Curcumin (CUR), a naturally occurring polyphenol derived from the root of Curcuma longa, has showed potent anticancer and cancer prevention activity in a variety of cancers. However, the clinical translation of CUR has been significantly hampered due to its extensive degradation, suboptimal pharmacokinetics, and poor bioavailability. To address these clinically relevant issues, we have developed a novel CUR-loaded magnetic nanoparticle (MNP-CUR) formulation. Herein, we have evaluated the in vitro and in vivo therapeutic efficacy of this novel MNP-CUR formulation in pancreatic cancer. Human pancreatic cancer cells (HPAF-II and Panc-1) exhibited efficient internalization of the MNP-CUR formulation in a dose-dependent manner. As a result, the MNP-CUR formulation effectively inhibited growth of HPAF-II and Panc-1 cells in cell proliferation and colony formation assays. The MNP-CUR formulation suppressed pancreatic tumor growth in an HPAF-II xenograft mouse model and improved the survival of mice by delaying tumor growth. The growth-inhibitory effect of MNP-CUR formulation correlated with the suppression of proliferating cell nuclear antigen (PCNA), B-cell lymphoma-extra large (Bcl-xL), induced myeloid leukemia cell differentiation protein (Mcl-1), cell surface-associated Mucin 1 (MUC1), collagen I, and enhanced membrane β-catenin expression. MNP-CUR formulation did not show any sign of hemotoxicity and was stable after incubation with human serum proteins. In addition, the MNP-CUR formulation improved serum bioavailability of CUR in mice up to 2.5-fold as compared with free CUR. Biodistribution studies show that a significant amount of MNP-CUR formulation was able to reach the pancreatic xenograft tumor(s), which suggests its clinical translational potential. In conclusion, this study suggests that our novel MNP-CUR formulation can be valuable for the treatment of pancreatic cancer.

Transferrin receptor-1 iron-acquisition pathway - synthesis, kinetics, thermodynamics and rapid cellular internalization of a holotransferrin-maghemite nanoparticle construct

BACKGROUND

Targeting nanoobjects via the iron-acquisition pathway is always reported slower than the transferrin/receptor endocytosis. Is there a remedy?

METHODS

Maghemite superparamagnetic and theragnostic nanoparticles (diameter 8.6nm) were synthesized, coated with 3-aminopropyltriethoxysilane (NP) and coupled to four holotransferrin (TFe2) by amide bonds (TFe2-NP). The constructs were characterized by X-ray diffraction, transmission electron microscopy, FTIR, X-ray Electron Spectroscopy, Inductively Coupled Plasma with Atomic Emission Spectrometry. The in-vitro protein/protein interaction of TFe2-NP with transferrin receptor-1 (R1) and endocytosis in HeLa cells were investigated spectrophotometrically, by fast T-jump kinetics and confocal microscopy.

RESULTS

In-vitro, R1 interacts with TFe2-NP with an overall dissociation constant KD=11nM. This interaction occurs in two steps: in the first, the C-lobe of the TFe2-NP interacts with R1 in 50μs: second-order rate constant, k1=6×10(10)M(-1)s(-1); first-order rate constant, k-1=9×10(4)s(-1); dissociation constant, K1d=1.5μM. In the second step, the protein/protein adduct undergoes a slow (10,000s) change in conformation to reach equilibrium. This mechanism is identical to that occurring with the free TFe2. In HeLa cells, TFe2-NP is internalized in the cytosol in less than 15min.

CONCLUSION

This is the first time that a nanoparticle-transferrin construct is shown to interact with R1 and is internalized in time scales similar to those of the free holotransferrin.

GENERAL SIGNIFICANCE

TFe2-NP behaves as free TFe2 and constitutes a model for rapidly targeting theragnostic devices via the main iron-acquisition pathway.

Curcumin nanomedicine: a road to cancer therapeutics

Cancer is the second leading cause of death in the United States. Conventional therapies cause widespread systemic toxicity and lead to serious side effects which prohibit their long term use. Additionally, in many circumstances tumor resistance and recurrence is commonly observed. Therefore, there is an urgent need to identify suitable anticancer therapies that are highly precise with minimal side effects. Curcumin is a natural polyphenol molecule derived from the Curcuma longa plant which exhibits anticancer, chemopreventive, chemo- and radio-sensitization properties. Curcumin's widespread availability, safety, low cost and multiple cancer fighting functions justify its development as a drug for cancer treatment. However, various basic and clinical studies elucidate curcumin's limited efficacy due to its low solubility, high rate of metabolism, poor bioavailability and pharmacokinetics. A growing list of nanomedicine(s) using first line therapeutic drugs have been approved or are under consideration by the Food and Drug Administration (FDA) to improve human health. These nanotechnology strategies may help to overcome challenges and ease the translation of curcumin from bench to clinical application. Prominent research is reviewed which shows that advanced drug delivery of curcumin (curcumin nanoformulations or curcumin nanomedicine) is able to leverage therapeutic benefits by improving bioavailability and pharmacokinetics which in turn improves binding, internalization and targeting of tumor(s). Outcomes using these novel drug delivery systems have been discussed in detail. This review also describes the tumor-specific drug delivery system(s) that can be highly effective in destroying tumors. Such new approaches are expected to lead to clinical trials and to improve cancer therapeutics.

Apoptosis-induced anticancer effect of transferrin-conjugated solid lipid nanoparticles of curcumin

Broad spectrum therapeutic potential of curcumin is usually hampered by its photodegradation and low bioavailability. Present investigation was designed with an objective to develop transferrin-mediated solid lipid nanoparticles (Tf-C-SLN) resistant to the photostability and capable of enhancing the bioavailability by targeted drug delivery to elicit anticancer activity against SH-SY5Y neuroblastoma cells in vitro. Hot homogenization method was used for the formulation of Tf-C-SLN and evaluated physicochemically using parameters such as, size, zeta potential, entrapment efficiency and photostability, transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), differential scanning colorimetry (DSC), and in vitro release study. In vitro cytotoxicity and apoptosis investigations were performed using microplate analysis and flow cytometry techniques. The physicochemical characterization confirmed the suitability of formulation method and various parameters therein. TEM investigation revealed the spherical morphology while NMR and DSC study confirmed the entrapment of curcumin inside the nanoparticles. The cytotoxicity, reactive oxygen species, and cell uptake were found to be increased considerably with Tf-C-SLN compared with curcumin-solubilized surfactant solution, and curcumin-loaded SLN (C-SLN) suggesting the targeting effect. AnnexinV-FITC/PI double staining, DNA analysis, caspase detection, and reduced mitochondrial potential confirmed the induction of apoptosis with nanoparticle treatment. Enhanced anticancer activity with Tf-C-SLN compared with curcumin-solubilized surfactant solution and C-SLN was observed from flow cytometry investigations with apoptosis being the major underlying mechanism. The in vitro observations of our investigation are very compelling and concrete to advocate the potential of Tf-C-SLN in enhancing the anticancer effect of curcumin against neuroblastoma in vivo and possible clinical applications.

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.

Formulation, antileukemia mechanism, pharmacokinetics, and biodistribution of a novel liposomal emodin

Emodin is a multifunctional Chinese traditional medicine with poor water solubility. D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) is a pegylated vitamin E derivate. In this study, a novel liposomal-emodin-conjugating TPGS was formulated and compared with methoxypolyethyleneglycol 2000-derivatized distearoyl-phosphatidylethanolamine (mPEG2000–DSPE) liposomal emodin. TPGS improved the encapsulation efficiency and stability of emodin egg phosphatidylcholine/cholesterol liposomes. A high encapsulation efficiency of 95.2% ± 3.0%, particle size of 121.1 ± 44.9 nm, spherical ultrastructure, and sustained in vitro release of TPGS liposomal emodin were observed; these were similar to mPEG2000–DSPE liposomes. Only the zeta potential of −13.1 ± 2.7 mV was significantly different to that for mPEG2000–DSPE liposomes. Compared to mPEG2000–DSPE liposomes, TPGS liposomes improved the cytotoxicity of emodin on leukemia cells by regulating the protein levels of myeloid cell leukemia 1 (Mcl-1), B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein, which was further enhanced by transferrin. TPGS liposomes prolonged the circulation time of emodin in the blood, with the area under the concentration–time curve (AUC) 1.7 times larger than for free emodin and 0.91 times larger than for mPEG2000–DSPE liposomes. In addition, TPGS liposomes showed higher AUC for emodin in the lung and kidney than for mPEG2000–DSPE liposomes, and both liposomes elevated the amount of emodin in the heart. Overall, TPGS is a pegylated agent that could potentially be used to compose a stable liposomal emodin with enhanced therapeutics.