Nanobody-mediated targeting of zinc phthalocyanine with polymer micelles as nanocarriers

Photodynamic therapy (PDT) is a suitable alternative to currently employed cancer treatments. However, the hydrophobicity of most photosensitizers (e.g., zinc phthalocyanine (ZnPC)) leads to their aggregation in blood. Moreover, non-specific accumulation in skin and low clearance rate of ZnPC leads to long-lasting skin photosensitization, forcing patients with a short life expectancy to remain indoors. Consequently, the clinical implementation of these photosensitizers is limited. Here, benzyl-poly(ε-caprolactone)-b-poly(ethylene glycol) micelles encapsulating ZnPC (ZnPC-M) were investigated to increase the solubility of ZnPC and its specificity towards cancers cells. Asymmetric flow field-flow fractionation was used to characterize micelles with different ZnPC-to-polymer ratios and their stability in human plasma. The ZnPC-M with the lowest payload (0.2 and 0.4% ZnPC w/w) were the most stable in plasma, exhibiting minimal ZnPC transfer to lipoproteins, and induced the highest phototoxicity in three cancer cell lines. Nanobodies (Nbs) with binding specificity towards hepatocyte growth factor receptor (MET) or epidermal growth factor receptor (EGFR) were conjugated to ZnPC-M to facilitate cell targeting and internalization. MET- and EGFR-targeting micelles enhanced the association and the phototoxicity in cells expressing the target receptor. Altogether, these results indicate that ZnPC-M decorated with Nbs targeting overexpressed proteins on cancer cells may provide a better alternative to currently approved formulations.

Harnessing anti-inflammatory pathways and macrophage nano delivery to treat inflammatory and fibrotic disorders

Targeting specific organs and cell types using nanotechnology and sophisticated delivery methods has been at the forefront of applicative biomedical sciences lately. Macrophages are an appealing target for immunomodulation by nanodelivery as they are heavily involved in various aspects of many diseases and are highly plastic in their nature. Their continuum of functional "polarization" states has been a research focus for many years yielding a profound understanding of various aspects of these cells. The ability of monocyte-derived macrophages to metamorphose from pro-inflammatory to reparative and consequently to pro-resolving effectors has raised significant interest in its therapeutic potential. Here, we briefly survey macrophages' ontogeny and various polarization phenotypes, highlighting their function in the inflammation-resolution shift. We review their inducing mediators, signaling pathways, and biological programs with emphasis on the nucleic acid sensing-IFN-I axis. We also portray the polarization spectrum of macrophages and the characteristics of their transition between different subtypes. Finally, we highlighted different current drug delivery methods for targeting macrophages with emphasis on nanotargeting that might lead to breakthroughs in the treatment of wound healing, bone regeneration, autoimmune, and fibrotic diseases.

Novel redox-sensitive thiolated TPGS based nanoparticles for EGFR targeted lung cancer therapy

Novel glutathione (GSH) redox-sensitive thiolated vitaminE-PEG1000-succinate (TPGH-SH) was synthesized by conjugating TPGS with 4-amino thiophenol (4-ATP) and confirmed by FTIR and NMR studies. Following, docetaxel (DTX) loaded, cetuximab (CTB) conjugated redox sensitive TPGS-SH nanoparticles (TPGS-SH NP) were prepared by dialysis method and screened for size, charge, DTX entrapment, which revealed that size, surface charge and percent entrapment are in the range of 183-227 nm, +18 to +26 mV and 68-71%. SEM, TEM, AFM have reflected the spherical and uniform size of NP with a smooth surface. In-vitro release studies were performed in media containing different concentrations of GSH to study their effect on drug release and drug release of up to 94.5%, at pH 5.5, GSH 20 mM, is observed within 24 h. The pH/redox sensitivity studies revealed the better stability of NP at higher pH and lower GSH concentrations. In-vitro cytotoxicity, cellular uptake, migration and apoptotic assays, performed on A549 cells, have proved that targeted formulation produced higher cytotoxicity (significantly less IC50 value) and uptake and also prevented cell migration. Pharmacokinetic and histopathological screening were performed on CF rats, which demonstrated promising results. The in-vivo efficacy studies on benzo(a)pyrene induced mice lung cancer model showed that targeted TPGS-SH NP has significantly reduced the cell number than the model control.

Gold liposomes for brain-targeted drug delivery: Formulation and brain distribution kinetics

This work was aimed to formulate transferrin (Tf) receptor targeted gold based theranostic liposomes which contain both docetaxel (DCX) and glutathione reduced gold nanoparticles (AuGSH) for brain-targeted drug delivery and imaging. AuGSH was prepared by reducing chloroauric acid salt using glutathione. The co-loading of DCX and AuGSH into liposomes was achieved by the solvent injection technique, and Tf was post-conjugated on the surface of the liposomes using carboxylated Vit-E TPGS (TPGS-COOH) as a linker. The liposomes were characterized for various parameters such as size, shape, surface charge, and drug release. The Tf receptor targeted gold liposomes were evaluated for the cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based colorimetric assay and in-vitro qualitative cellular uptake studies using confocal microscopy. The in-vivo site specific delivery of DCX was analyzed by the brain distribution study of DCX in comparison with marketed formulation (Docel™). A sustained drug release of about 70% was observed from liposomes in the span of 72 h. The in-vivo results demonstrated that targeted gold liposomes were able to deliver DCX into the brain by 3.70, 2.74 and 4.08-folds higher than Docel™ after 30, 120 and 240 min of the treatment, respectively. Besides, the results of these studies have suggested the feasibility of Tf decorated AuGSH and DCX co-loaded liposomes as a promising platform for targeted nano-theranostics.

Reinforcing mitochondrial functions in aging brain: An insight into Parkinson's disease therapeutics

Mitochondria, the powerhouse of the neural cells in the brain, are also the seat of certain essential gene signaling pathways that control neuronal functions. Deterioration of mitochondrial functions has been widely reported in normal aging as well as in a spectrum of age-associated neurological diseases, including Parkinson's disease (PD). Evidences accumulated in the recent past provide not only advanced information on the causes of mitochondrial bioenergetics defects and redox imbalance in PD brains, but also much insight into mitochondrial biogenesis, quality control of mitochondrial proteins, and genes, which regulate intra- and extra-mitochondrial signaling that control the general health of neural cells. The mitochondrial quality control machinery is affected in aging and especially in PD, thus affecting intraneuronal protein transport and degradation, which are primarily responsible for accumulation of misfolded proteins and mitochondrial damage in sporadic as well as familial PD. Essentially we considered in the first half of this review, mitochondria-based targets such as mitochondrial oxidative stress and mitochondrial quality control pathways in PD, relevance of mitochondrial DNA mutations, mitophagy, mitochondrial proteases, mitochondrial flux, and finally mitochondria-based therapies possible for PD. Therapeutic aspects are considered in the later half and mitochondria-targeted antioxidant therapy, mitophagy enhancers, mitochondrial biogenesis boasters, mitochondrial dynamics modulators, and gene-based therapeutic approaches are discussed. The present review is a critical assessment of this information to distinguish some exemplary mitochondrial therapeutic targets, and provides a utilitarian perception of some avenues for therapeutic designs on identified mitochondrial targets for PD, a very incapacitating disorder of the geriatric population, world over.

Galectin-1-based tumour-targeting for gold nanostructure-mediated photothermal therapy

PURPOSE

To demonstrate delivery of Au nanocages to cells using the galectin-1 binding peptide anginex (Ax) and to demonstrate the value of this targeting for selective in vitro photothermal cell killing.

MATERIALS AND METHODS

Au nanocages were synthesised, coated with polydopamine (PDA), and conjugated with Ax. Tumour and endothelial cell viability was measured with and without laser irradiation. Photoacoustic (PA) mapping and PA flow cytometry were used to confirm cell targeting in vitro and in tissue slices ex vivo.

RESULTS

Cell viability was maintained at ≥50% at 100 pM suggesting low toxicity of the nanocage alone. Combining the targeted construct (25 pM) with low power 808 nm laser irradiation for 10-20 min (a duration previously shown to induce rapid and sustained heating of Au nanocages [AuNC] in solution), resulted in over 50% killing of endothelial and tumour cells. In contrast, the untargeted construct combined with laser irradiation resulted in negligible cell killing. We estimate approximately 6 × 10⁴ peptides were conjugated to each nanocage, which also resulted in inhibition of cell migration. Binding of the targeted nanocage reached a plateau after three hours, and cell association was 20-fold higher than non-targeted nanocages both in vitro and ex vivo on tumour tissue slices. A threefold increase in tumour accumulation was observed in preliminary in vivo studies.

CONCLUSIONS

These studies demonstrate Ax's potential as an effective targeting agent for Au-based theranostics to tumour and endothelial cells, enabling photothermal killing. This platform further suggests potential for multimodal in vivo therapy via next-generation drug-loaded nanocages.

Hyperthermia-triggered drug delivery from iRGD-modified temperature-sensitive liposomes enhances the anti-tumor efficacy using high intensity focused ultrasound

An important limitation to successful cancer treatment with chemotherapeutics is the inability to achieve therapeutically effective drug concentrations while avoiding healthy tissue damage. In this work, a new tumor-targeting peptide iRGD (CCRGDKGPDC) was used to modify drug-loaded low temperature-sensitive liposomes (iRGD-LTSL-DOX) to explore the anti-tumor effects in combination with high intensity focused ultrasound (HIFU) in vitro and in vivo. iRGD-LTSL-DOX can specifically target to ανβ3-positive cells and locally release the encapsulated doxorubicin (DOX) in a hyperthermia-triggered manner. In vivo results showed that DOX from iRGD-LTSL-DOX was intravascularly released and rapidly penetrated into tumor interstitial space after HIFU-triggered heat treatment, thereby overcoming the limited tumor penetration of anticancer drugs. Significantly stronger anti-tumor efficacy further supported the effective combination of iRGD-LTSL-DOX with HIFU-induced hyperthermia. Our study provided a novel tumor-targeting LTSL-DOX and demonstrated its usefulness in HIFU-induced hyperthermia-triggered drug delivery.

Effective treatment of glioblastoma requires crossing the blood-brain barrier and targeting tumors including cancer stem cells: The promise of nanomedicine

Glioblastoma multiforme (GBM) is the most aggressive and lethal type of brain tumor. Both therapeutic resistance and restricted permeation of drugs across the blood-brain barrier (BBB) play a major role in the poor prognosis of GBM patients. Accumulated evidence suggests that in many human cancers, including GBM, therapeutic resistance can be attributed to a small fraction of cancer cells known as cancer stem cells (CSCs). CSCs have been shown to have stem cell-like properties that enable them to evade traditional cytotoxic therapies, and so new CSC-directed anti-cancer therapies are needed. Nanoparticles have been designed to selectively deliver payloads to relevant target cells in the body, and there is considerable interest in the use of nanoparticles for CSC-directed anti-cancer therapies. Recent advances in the field of nanomedicine offer new possibilities for overcoming CSC-mediated therapeutic resistance and thus significantly improving management of GBM. In this review, we will examine the current nanomedicine approaches for targeting CSCs and their therapeutic implications. The inhibitory effect of various nanoparticle-based drug delivery system towards CSCs in GBM tumors is the primary focus of this review.