Nanostructured delivery system for zinc phthalocyanine: preparation, characterization, and phototoxicity study against human lung adenocarcinoma A549 cells

Photodynamic therapy of lung cancer, where are we?

Lung cancer remains the leading threat of death globally, killing more people than colon, breast, and prostate cancers combined. Novel lung cancer treatments are being researched because of the ineffectiveness of conventional cancer treatments and the failure of remission. Photodynamic therapy (PDT), a cancer treatment method that is still underutilized, is a sophisticated cancer treatment that shows selective destruction of malignant cells via reactive oxygen species production. PDT has been extensively studied in vitro and clinically. Various PDT strategies have been shown to be effective in the treatment of lung cancer. PDT has been shown in clinical trials to considerably enhance the quality of life and survival in individuals with incurable malignancies. Furthermore, PDT, in conjunction with the use of nanoparticles, is currently being researched for use as an effective cancer treatment, with promising results. PDT and the new avenue of nanoPDT, which are novel treatment options for lung cancer with such promising results, should be tested in clinical trials to determine their efficacy and side effects. In this review, we examine the status and future potentials of nanoPDT in lung cancer treatment.

Green synthesis of bimetallic ZnO-CuO nanoparticles and their cytotoxicity properties

In this study, a simple and green strategy was reported to prepare bimetallic nanoparticles (NPs) by the combination of zinc oxide (ZnO) and copper oxide (CuO) using Sambucus nigra L. extract. The physicochemical properties of these NPs such as crystal structure, size, and morphology were studied by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM), and transmission electron microscopy (TEM). The results suggested that these NPs contained polygonal ZnO NPs with hexagonal phase and spherical CuO NPs with monoclinic phase. The anticancer activity of the prepared bimetallic NPs was evaluated against lung and human melanoma cell lines based on MTT assay. As a result, the bimetallic ZnO/CuO NPs exhibited high toxicity on melanoma cancer cells while their toxicity on lung cancer cells was low.

Enhanced photo/chemo combination efficiency against bladder tumor by encapsulation of DOX and ZnPC into in situ-formed thermosensitive polymer hydrogel

BACKGROUND

Chemotherapy after transurethral resection is commonly recommended for bladder cancer. However, studies have shown that chemotherapy solely can hardly decrease progression rates of bladder cancer. The combination of chemotherapeutic agents with photo-dynamic therapy (PDT), a new promising localized therapy, may become a workable strategy for combating bladder cancer. This study reports the combination of doxorubicin (DOX)-based chemotherapy and zinc phthalocyanine (ZnPC)-based PDT using in situ-formed thermal-responsive copolymer hydrogel.

MATERIALS AND METHODS

The copolymer was synthesized by polymerization of 3-caprolactone, 1,4,8-trioxa[4.6]spiro-9-undecanone and poly(ethylene glycol) and was abbreviated as PCL-PTSUO-PEG. The thermal-responsive nanoparticles (TNPs) were prepared by the nanoprecipitation technology. The thermal-responsive hydrogel was formed after 37°C heating of TNP solution. The size, morphology and dynamic viscosity of hydrogel were detected. The in vitro drug release profile of TNP/DOX/ZnPC was performed. Cell uptake, cell inhibition and ROS generation of TNP/DOX/ZnPC were studied in 5637 cells. The in vivo antitumor activity of TNP/DOX/ZnPC was evaluated in nude mice bearing 5637 cells xenograft.

RESULTS

TNP/DOX and TNP/ZnPC had an average diameter of 102 and 108 nm, respectively. After being heated at 37°C for 5 minutes, TNP/DOX and TNP/ZnPC solution turned uniform light red and dark green hydrogel. ZnPC encapsulation designed by TNP could significantly improve its aqueous solubility to 1.9 mg/mL. Cell inhibition showed that the best cell inhibition was found, with cell viability of 18.5%, when the weight ratio of DOX and ZnPC encapsulated in the TNP reached about 1:5. TNP/DOX/ZnPC generated relative high level of ROS with 4.8-fold of free ZnPC and 1.6-fold of TNP/ZnPC. TNP/DOX/ZnPC showed only 8-fold of relative tumor growth without obvious toxicity to the mice.

CONCLUSION

Thermosensitive thermal-responsive hydrogel reported in this contribution are promising in situ-formed matrix for DOX- and ZnPC-based photo/chemo combination treatment for bladder cancer therapy.

Location of Varying Hydrophobicity Zinc(II) Phthalocyanine-Type Photosensitizers in Methoxy Poly(ethylene oxide) and Poly(l-lactide) Block Copolymer Micelles Using 1H NMR and XPS Techniques

Hydrophobic zinc(II) phthalocyanine-type derivatives, solubilized in polymeric micelles (PMs), provide a befitting group of so-called nanophotosensitizers, suitable for a variety of photodynamic therapy (PDT) protocols. The factors that influence the success of such products in PDT are the location of the active cargo in the PMs and the nanocarrier-enhanced ability to safely interact with biological systems and fulfill their therapeutic functions. Therefore, the aim of this work was to determine the solubilization loci of three phthalocyanines of varying hydrophobicity, i.e., zinc(II) phthalocyanine (ZnPc), along with its tetrasulfonic acid (ZnPc-sulfo₄) and perfluorinated (ZnPcF₁₆) derivatives, loaded in polymeric micelles of methoxy poly(ethylene oxide)-b-poly(l-lactide) (mPEG-b-PLLA), by means of ¹H nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) combined with ion sputtering. Furthermore, the microenvironment influence upon the chemical and physical status of the solubilized cargo in PMs, expressed by photobleaching and reactive oxygen species (ROS) generation comparing to the same properties of native cargoes in solution, was also evaluated and discussed in regards to the probing location data. The studied phthalocyanine-loaded PMs exhibited good physical stability, high drug-loading efficiency, and a size of less than ca. 150 nm with low polydispersity indices. The formation of polymeric micelles and the solubilization locus were investigated by ¹H NMR and XPS. ZnPc localized within the PM core, whereas both ZnPcF₁₆ and ZnPc-sulfo₄ - in the corona of PMs. We proved that the cargo locus is crucial for the photochemical properties of the studied phthalocyanines; the increase in photostability and ability to generate ROS in micellar solution compared to free photosensitizer was most significant for the photosensitizer in the PM core. Our results indicate the role of the cargo location in the PM microenvironment and demonstrate that such attempts are fundamental for improving the properties of photosensitizers and their assumed efficiency as nanophotosensitizers in PDT.

Selective aggregation of PAMAM dendrimer nanocarriers and PAMAM/ZnPc nanodrugs on human atheromatous carotid tissues: a photodynamic therapy for atherosclerosis

Photodynamic therapy (PDT) involves the action of photons on photosensitive molecules, where atomic oxygen or OH(-) molecular species are locally released on pathogenic human cells, which are mainly carcinogenic, thus causing cell necrosis. The efficacy of PDT depends on the local nanothermodynamic conditions near the cell/nanodrug system that control both the level of intracellular translocation of nanoparticles in the pathogenic cell and their agglomeration on the cell membrane. Dendrimers are considered one of the most effective and promising drug carriers because of their relatively low toxicity and negligible activation of complementary reactions. Polyamidoamine (PAMAM) dendrite delivery of PDT agents has been investigated in the last few years for tumour selectivity, retention, pharmacokinetics and water solubility. Nevertheless, their use as drug carriers of photosensitizing molecules in PDT for cardiovascular disease, targeting the selective necrosis of macrophage cells responsible for atheromatous plaque growth, has never been investigated. Furthermore, the level of aggregation, translocation and nanodrug delivery efficacy of PAMAM dendrimers or PAMAM/zinc phthalocyanine (ZnPc) conjugates on human atheromatous tissue and endothelial cells is still unknown. In this work, the aggregation of PAMAM zero generation dendrimers (G0) acting as drug delivery carriers, as well as conjugated G0 PAMAM dendrimers with a ZnPc photosensitizer, to symptomatic and asymptomatic human carotid tissues was investigated by using atomic force microscopy (AFM). For the evaluation of the texture characteristics of the AFM images, statistical surface morphological and fractal analytical methodologies and Minkowski functionals were used. All statistical quantities showed that the deposition of nanodrug carriers on healthy tissue has an inverse impact when comparing to the deposition on atheromatous tissue with different aggregation features between G0 and G0/ZnPc nanoparticles and with considerably larger G0/ZnPc aggregations on the atheromatous plaque. The results highlight the importance of using PAMAM dendrimer carriers as a novel and promising PDT platform for atherosclerosis therapies.

Aluminum-phthalocyanine chloride associated to poly(methyl vinyl ether-co-maleic anhydride) nanoparticles as a new third-generation photosensitizer for anticancer photodynamic therapy

Photodynamic therapy is generally considered to be safer than conventional anticancer therapies, and it is effective against different kinds of cancer. However, its clinical application has been significantly limited by the hydrophobicity of photosensitizers. In this work, a system composed of the hydrophobic photosensitizer aluminum–phthalocyanine chloride (AlPc) associated with water dispersible poly(methyl vinyl ether-co-maleic anhydride) nanoparticles is described. AlPc was associated with nanoparticles produced by a method of solvent displacement. This system was analyzed for its physicochemical characteristics, and for its photodynamic activity in vitro in cancerous (murine mammary carcinoma cell lineage 4T1, and human mammary adenocarcinoma cells MCF-7) and noncancerous (murine fibroblast cell lineage NIH/3T3, and human mammary epithelial cell lineage MCF-10A) cell lines. Cell viability and the elicited mechanisms of cell death were evaluated after the application of photodynamic therapy. This system showed improved photophysical and photochemical properties in aqueous media in comparison to the free photosensitizer, and it was effective against cancerous cells in vitro.

Vehiculization determines the endocytic internalization mechanism of Zn(II)-phthalocyanine

It is generally accepted that compounds of nanomolecular size penetrate into cells by different endocytic processes. The vehiculization strategy of a compound is a factor that could determine its uptake mechanism. Understanding the influence of the vehicle in the precise mechanism of drug penetration into cells makes possible to improve or modify the therapeutic effects. In this study, using human A-549 cells, we have characterized the possible internalization mechanism of the photosensitizer Zn(II)-phthalocyanine (ZnPc), either dissolved in dimethylformamide (ZnPc-DMF) or included in liposomes of dipalmitoyl-phosphatidyl-choline. Specific inhibitors involved in the main endocytic pathways were used. Co-incubation of cells with ZnPc-liposomes and dynasore (dinamin-mediated endocytosis inhibitor) resulted in a significant decrease of photodamage, whereas other inhibitors did not alter the photodynamic effect of ZnPc. On the contrary, cells treated with ZnPc-DMF in the presence of dynasore, genistein (caveolin-mediated endocytosis inhibitor) or cytochalasin D (macropinocytosis and caveolin-mediated endocytosis inhibitor) showed a significant decrease in ZnPc uptake and photodynamic damage. These results suggest that ZnPc-DMF penetrates into cells mainly by caveolin-mediated endocytosis, whereas ZnPc-liposomes are internalized into cells preferentially by clathrin-mediated endocytosis. We conclude that using different drug vehiculization systems, it is possible to modify the internalization mechanism of a therapeutic compound, which could be of great interest in clinical research.