Zinc phthalocyanine encapsulated in polymer micelles as a potent photosensitizer for the photodynamic therapy of osteosarcoma

Phthalocyanine-based probes in alleviating or evading tumour-hypoxia for enhanced photo- and/ sono-mediated therapeutic efficacies

This review discusses the possible methods for improving therapeutic efficacies of phthalocyanine (Pcs) -based therapeutic probes in photo- and sono-dynamic therapies under hypoxic conditions. Herein, the structural design strategies including varying the central metal, position substituents and the effects of adjuvant used in supplementing the therapeutics activities of Pcs or formation of NPs are discussed for cancer therapies in hypoxic conditions. Different mechanisms induced for cell death influenced by the compositions of the Pcs-probes are discussed. The focus mainly highlights the oxygen (O2) -dependent mechanisms including methods of supplementing tumour microenvironment O2-concentrations to promote PDT or SDT therapies. Alternatively, O2-independent mechanisms mainly used to evade hypoxia by stimulating anticancer processes that don't require O2 to initiate cell death, such as the Fenton reaction or thermal ablation effects.

Anti-Melanoma Activity of Single Intratumoral Injection of ZnPc Micelles Mixed With in situ Gel in B16 Bearing Mouse

Photodynamic therapy (PDT) is a potential treatment strategy for melanoma. As a second-generation photosensitizer, Zinc phthalocyanine (ZnPc) has many advantages for anti-tumor PDTs, such as strong absorption in the red and near infrared regions, high photo and chemical stability, etc. However, ZnPc has a poor water solubility and is apt to aggregate due to the π-π interaction between molecules, which limits its applications. In this study, various solvents and surfactants were screened for dissolving ZnPc and preparing ZnPc@SDC-TPGS micelle and thermosensitive in situ gel. After the cytotoxic effects of thermosensitive gels on PDT were tested, the antitumor effects on PDT of them in mice by intratumoral injection were evaluated, including body weight, and tumor weight, volume and morphology. The cell death pathway and the relationship of reactive oxygen species yield with apoptotic rate of tumor cells induced by ZnPc in situ gel were investigated. The results were that N-methyl-pyrrolidone (NMP) mixed with 2 % SDC and aqueous solution containing 2 % TPGS and 2 % SDC were used to synthesize ZnPc@SDC-TPGS micelle and the thermosensitive in situ gel. The cytotoxic effects of thermosensitive gels showed good tumor suppression of ZnPc@SDC-TPGS in situ gel and no toxicity of the blank gel. Intratumoral injection in situ gel containing 3 µg ZnPc under irradiation demonstrated good tumor inhibition in mice with melanoma. Apoptosis has been established as the primary pathway of cell death, and the production of reactive oxygen species (ROS) plays a crucial role in cellular apoptosis induced by ZnPc@SDC-TPGS in situ gel. In conclusion, the intratumoral injection of ZnPc@SDC-TPGS thermosensitive in situ gel provides a promising local treatment option for melanoma.

Graphene Oxide (GO) for the Treatment of Bone Cancer: A Systematic Review and Bibliometric Analysis

Cancer is a severe disease that, in 2022, caused more than 9.89 million deaths worldwide. One worrisome type of cancer is bone cancer, such as osteosarcoma and Ewing tumors, which occur more frequently in infants. This study shows an active interest in the use of graphene oxide and its derivatives in therapy against bone cancer. We present a systematic review analyzing the current state of the art related to the use of GO in treating osteosarcoma, through evaluating the existing literature. In this sense, studies focused on GO-based nanomaterials for potential applications against osteosarcoma were reviewed, which has revealed that there is an excellent trend toward the use of GO-based nanomaterials, based on their thermal and anti-cancer activities, for the treatment of osteosarcoma through various therapeutic approaches. However, more research is needed to develop highly efficient localized therapies. It is suggested, therefore, that photodynamic therapy, photothermal therapy, and the use of nanocarriers should be considered as non-invasive, more specific, and efficient alternatives in the treatment of osteosarcoma. These options present promising approaches to enhance the effectiveness of therapy while also seeking to reduce side effects and minimize the damage to surrounding healthy tissues. The bibliometric analysis of photothermal and photochemical treatments of graphene oxide and reduced graphene oxide from January 2004 to December 2022 extracted 948 documents with its search strategy, mainly related to research papers, review papers, and conference papers, demonstrating a high-impact field supported by the need for more selective and efficient bone cancer therapies. The central countries leading the research are the United States, Iran, Italy, Germany, China, South Korea, and Australia, with strong collaborations worldwide. At the same time, the most-cited papers were published in journals with impact factors of more than 6.0 (2021), with more than 290 citations. Additionally, the journals that published the most on the topic are high impact factor journals, according to the analysis performed, demonstrating the high impact of the research field.

Nanobiotechnological approaches in osteosarcoma therapy: Versatile (nano)platforms for theranostic applications

Constructive achievements in the field of nanobiotechnology and their translation into clinical course have led to increasing attention towards evaluation of their use for treatment of diseases, especially cancer. Osteosarcoma (OS) is one of the primary bone malignancies that affects both males and females in childhood and adolescence. Like other types of cancers, genetic and epigenetic mutations account for OS progression and several conventional therapies including chemotherapy and surgery are employed. However, survival rate of OS patients remains low and new therapies in this field are limited. The purpose of the current review is to provide a summary of nanostructures used in OS treatment. Drug and gene delivery by nanoplatforms have resulted in an accumulation of therapeutic agents for tumor cell suppression. Furthermore, co-delivery of genes and drugs by nanostructures are utilized in OS suppression to boost immunotherapy. Since tumor cells have distinct features such as acidic pH, stimuli-responsive nanoparticles have been developed to appropriately target OS. Besides, nanoplatforms can be used for biosensing and providing phototherapy to suppress OS. Furthermore, surface modification of nanoparticles with ligands can increase their specificity and selectivity towards OS cells. Clinical translation of current findings suggests that nanoplatforms have been effective in retarding tumor growth and improving survival of OS patients.

Modification and Functionalization of Polymers for Targeting to Bone Cancer and Bone Regeneration

Bone is one of the most complex, inaccessible body structures, responsible for calcium storage and haematopoiesis. The second highest cause of death across the world is cancer. Amongst all the types of cancers, bone cancer treatment modalities are limited due to the structural complexity and inaccessibility of bones. The worldwide incidence of bone diseases and bone defects due to cancer, infection, trauma, age-related bone degeneration is increasing. Currently different conventional therapies are available for bone cancer such as chemotherapy, surgery and radiotherapy, but they have several disadvantages associated with them. Nanomedicine is being extensively researched as viable therapeutics to mitigate drug resistance in cancer therapy and promote bone regeneration. Several natural polymers such as chitosan, dextran, alginate, hyaluronic acid, and synthetic polymers like polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone are investigated for their application in nanomedicine for bone cancer treatment and bone regeneration. Nanocarriers have shown promising results in preclinical experimental studies. However, they still face a major drawback of inadequate targetability. The paper summarizes the status of research and the progress made so far in modifications and functionalization of natural polymers for improving their site specificity and targeting for effective treatment of bone cancer and enhancing bone regeneration.

The safety and efficiency of photodynamic therapy for the treatment of osteosarcoma: A systematic review of in vitro experiment and animal model reports

BACKGROUND

Osteosarcoma (OS) is an aggressive malignant bone tumour with high mortality. A poor prognosis is noted in patients with distal metastases or multidrug resistance. As an emerging antitumor strategy, photodynamic therapy (PDT) mediated by visible and near infrared light has attracted intensive attention given its target selectivity, remote controllability, minimal or non-invasive features. However, PDT also has obvious limitations. Specifically, due to the limited penetration of light, it is mainly used in the clinical treatment of superficial malignant tumours, such as musculoskeletal sarcomas and melanoma, but it has not been applied to the clinical treatment of deep malignant bone tumours except for a very small number of experiments on deep canine OS models.

MATERIALS AND METHODS

We searched for studies that focused on the effectiveness and safety of PDT for OS based on in vitro experiments and animal models in the last decade. A systematic search was conducted using electronic databases, including PubMed, ClinicalTrials.gov, and the Cochrane Library.

INCLUSION CRITERIA

(1) original research articles about PDT for OS; (2) articles in English; (3) in vitro or animal model research; and (4) detailed information, including cell name, fluence, irradiation wavelength, time of incubation with PS, duration between PS treatment and irradiation, and duration between irradiation and viability assays.

EXCLUSION CRITERIA

(1) study was a review/systemic review article, patent, letter, or conference abstract/paper; (2) articles were not published in English; (3) studies containing overlapping or insufficient data.

RESULTS

We identified 201 publications, and 44 articles met the inclusion criteria and were included in the synthesis. Unfortunately, there are no relevant clinical reports of the use of PDT in the treatment of human OS. In these studies, 8 studies only employed in vivo experiments to evaluate the efficiency of PDT in an OS animal model, 19 studies exclusively performed in vitro viability assays of cells treated with PDT under different conditions, and 17 studies included in vitro cell experiments and in vivo animal OS models to evaluate the effect of PDT on OS in vivo and in vitro. All studies have shown that PDT is cytotoxic to OS cells or can inhibit the growth of OS in heterologous or homologous animal OS models but exhibits minimal cytotoxicity at a certain range of dosages.

CONCLUSION

Based on this systematic review, PDT can eradicate OS cells in cell culture and there is some evidence for efficacy in animal models. However, the ability for PDT to control human OS is unclear, the animal and human reports do not show evidence of human OS control, they just do show feasibility. The major issues concerning the potential for treatment of osteosarcoma with PDT are that adequate light should be transmitted to tumor loci and if the disease is caught before metastasis and irradiation of tumor sites is feasible, curative potential is there. Otherwise, PDT may be mainly palliative. To determine whether PDT can safely and efficiently be used in the clinical treatment of OS, many preclinical orthotopic animal OS models and OS models of multiple systemic metastases must be performed and interstitial PDT or intraoperative PDT may be a good and potential candidate for human OS treatment. If these problems can be well solved, PDT may be a potentially effective strategy for the treatment of OS patients.

Current Status and Prospects of Targeted Therapy for Osteosarcoma

Osteosarcoma (OS) is a highly malignant tumor occurring in bone tissue with a high propensity to metastasize, and its underlying mechanisms remain largely elusive. The OS prognosis is poor, and improving the survival of OS patients remains a challenge. Current treatment methods such as surgical approaches, chemotherapeutic drugs, and immunotherapeutic drugs remain ineffective. As research progresses, targeted therapy is gradually becoming irreplaceable. In this review, several treatment modalities for osteosarcoma, such as surgery, chemotherapy, and immunotherapy, are briefly described, followed by a discussion of targeted therapy, the important targets, and new technologies for osteosarcoma treatment.

Progress of phototherapy for osteosarcoma and application prospect of blue light photobiomodulation therapy

Osteosarcoma (OS) is the most common primary malignant bone tumor that mainly affects the pediatric and adolescent population; limb salvage treatment has become one of the most concerned and expected outcomes of OS patients recently. Phototherapy (PT), as a novel, non-invasive, and efficient antitumor therapeutic approach including photodynamic therapy (PDT), photothermal therapy (PTT), and photobiomodulation therapy (PBMT), has been widely applied in superficial skin tumor research and clinical treatment. OS is the typical deep tumor, and its phototherapy research faces great limitations and challenges. Surprisingly, pulse mode LED light can effectively improve tissue penetration and reduce skin damage caused by high light intensity and has great application potential in deep tumor research. In this review, we discussed the research progress and related molecular mechanisms of phototherapy in the treatment of OS, mainly summarized the status quo of blue light PBMT in the scientific research and clinical applications of tumor treatment, and outlooked the application prospect of pulsed blue LED light in the treatment of OS, so as to further improve clinical survival rate and prognosis of OS treatment and explore corresponding cellular mechanisms.

Dimensional Reduction Enhances Photodynamic Therapy of Metal-Organic Nanophotosensitizers

Herein we report that dimensional reduction from three-dimensional nanoscale metal-organic frameworks (nMOFs) to two-dimensional nanoscale metal-organic layers (nMOLs) increases the frequency of encounters between photosensitizers and oxygen and facilitates the diffusion of singlet oxygen from the nMOL to significantly enhance photodynamic therapy. The nMOFs and nMOLs share the same M12-oxo (M = Zr, Hf) secondary building units and 5,15-di-p-benzoatoporphyrin (DBP) ligands but exhibit three-dimensional and two-dimensional topologies, respectively. Molecular dynamics simulations and experimental studies revealed that the nMOLs with a monolayer morphology enhanced the generation of reactive oxygen species and exhibited over an order of magnitude higher cytotoxicity over the nMOFs. In a mouse model of triple-negative breast cancer, Hf-DBP nMOL showed 49.1% more tumor inhibition, an 80% higher cure rate, and 16.3-fold lower metastasis potential than Hf-DBP nMOF.

Effect of tertiary amino groups in the hydrophobic segment of an amphiphilic block copolymer on zinc phthalocyanine encapsulation and photodynamic activity

Polymer micelles are promising nanocarriers for hydrophobic photosensitizers of photodynamic therapy (PDT). Poly(styrene-co-(2-(N,N-dimethylamino)ethyl acrylate))-block-poly(polyethylene glycol monomethyl ether acrylate) (P(St-co-DMAEA)-b-PPEGA; 1) was prepared via reversible addition and fragmentation chain transfer (RAFT) polymerization as a carrier for a zinc phthalocyanine (ZnPc) photosensitizer to be used in PDT. The DMAEA-unit composition in the P(St-co-DMAEA) segment was adjusted to 0.40 molar ratio, which caused a sharp increase in water-solubility when the pH decreased from 7.4 to 5.0. The polymer 1 micelle size distribution also shifted to lower when the pH decreased, whereas this change was not observed in PSt-co-PPEGA (2), which was previously reported. The UV-vis spectrum of the ZnPc-loaded micelles of polymer 1 exhibited relatively sharp Q bands, comparable to those measured in DMSO, indicating good compatibility of the condensed core with ZnPc. ZnPc-loaded micelles of polymer 1 exerted excellent photocytotoxicity in the MNNG-induced mutant of the rat murine RGM-1 gastric epithelial cell line (RGK-1). In contrast, the ZnPc-loaded micelles of polymer 2 were completely inactive under the same conditions. Fluorescence from the RGK-1 cells treated with ZnPc-loaded micelles of polymer 1 was observed after 4 h of co-incubation, while no fluorescence was observed in cells treated with ZnPc-loaded micelles of polymer 2. These results indicate that the pH-responsive nature and good compatibility with ZnPc exhibited by the polymer 1 micelles are essential characteristics of ZnPc carriers for efficient photodynamic therapy.

Tertiary amino groups in the hydrophobic core of polymer micelles affect the encapsulation and photodynamic activity of zinc phthalocyanine.

Photodynamic Therapy with Zinc Phthalocyanine Inhibits the Stemness and Development of Colorectal Cancer: Time to Overcome the Challenging Barriers?

Photodynamic therapy (PDT) is a light-based cancer therapy approach that has shown promising results in treating various malignancies. Growing evidence indicates that cancer stem cells (CSCs) are implicated in tumor recurrence, metastasis, and cancer therapy resistance in colorectal cancer (CRC); thus, targeting these cells can ameliorate the prognosis of affected patients. Based on our bioinformatics results, SOX2 overexpression is significantly associated with inferior disease-specific survival and worsened the progression-free interval of CRC patients. Our results demonstrate that zinc phthalocyanine (ZnPc)-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially decrease tumor migration via downregulating MMP9 and ROCK1 and inhibit the clonogenicity of SW480 cells via downregulating CD44 and SOX2. Despite inhibiting clonogenicity, ZnPc-PDT with 12 J/cm2 irradiation fails to downregulate CD44 expression in SW480 cells. Our results indicate that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially reduce the cell viability of SW480 cells and stimulate autophagy in the tumoral cells. Moreover, our results show that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially arrest the cell cycle at the sub-G1 level, stimulate the intrinsic apoptosis pathway via upregulating caspase-3 and caspase-9 and downregulating Bcl-2. Indeed, our bioinformatics results show considerable interactions between the studied CSC-related genes with the studied migration- and apoptosis-related genes. Collectively, the current study highlights the potential role of ZnPc-PDT in inhibiting stemness and CRC development, which can ameliorate the prognosis of CRC patients.

Zinc pthalocyanine loaded poly (lactic acid) nanoparticles by double emulsion methodology for photodynamic therapy against 9 L/LacZ gliosarcoma cells

Development delivery systems, such as nanoparticles, represent a growing area in biomedical research. Nanoparticles (NP) were prepared using a double-emulsion method to load zinc(II) phthalocyanine (ZnPc). NP were obtained using poly (lactic acid) (PLA). ZnPc is a second generation of photosensitizer used in photodynamic therapy (PDT). ZnPc loaded PLA nanoparticles (NPLA-ZnPc) were prepared by double-emulsion method, characterized and available in cellular culture. The mean nanoparticle size presented particle size was 384.7 ± 84.2 nm with polydispersity index (PDI) of 0.150 ± 0.015, and the encapsulation efficiency was of 83%. The nanoparticle formulations presented negative zeta potential values (-27.5 ± 1.0 mV), explaining their colloidal stability. ZnPc loaded nanoparticles maintain its photophysical behavior after encapsulation. Photosensitizer release from nanoparticles was sustained over 168 h with a biphasic ZnPc release profile. An in vitro phototoxic effect in range of 80% was observed in 9 L/LacZ gliosarcoma cells at laser light doses (10 J cm^-2) with 3.0 µg mL^-1 of NPLA-ZnPc. All the physical-chemical, photophysical and photobiological measurements performed allow us to conclude that ZnPc loaded PLGA nanoparticles is a promising drug delivery system for PDT.

Recent Progress in Phthalocyanine-Polymeric Nanoparticle Delivery Systems for Cancer Photodynamic Therapy

This perspective article summarizes the last decade’s developments in the field of phthalocyanine (Pc)-polymeric nanoparticle (NP) delivery systems for cancer photodynamic therapy (PDT), including studies with at least in vitro data. Moreover, special attention will be paid to the various strategies for enhancing the behavior of Pc-polymeric NPs in PDT, underlining the great potential of this class of nanomaterials as advanced Pcs’ nanocarriers for cancer PDT. This review shows that there is still a lot of research to be done, opening the door to new and interesting nanodelivery systems.

Nanoscale Metal-Organic Framework Confines Zinc-Phthalocyanine Photosensitizers for Enhanced Photodynamic Therapy

The performance of photodynamic therapy (PDT) depends on the solubility, pharmacokinetic behaviors, and photophysical properties of photosensitizers (PSs). However, highly conjugated PSs with strong reactive oxygen species (ROS) generation efficiency tend to have poor solubility and aggregate in aqueous environments, leading to suboptimal PDT performance. Here, we report a new strategy to load highly conjugated but poorly soluble zinc-phthalocyanine (ZnP) PSs in the pores of a Hf₁₂-QC (QC = 2″,3′-dinitro-[1,1’:4′,1”;4″,1’”-quaterphenyl]-4,4’”-dicarboxylate) nanoscale metal–organic framework to afford ZnP@Hf-QC with spatially confined ZnP PSs. ZnP@Hf-QC avoids aggregation-induced quenching of ZnP excited states to significantly enhance ROS generation upon light irradiation. With higher cellular uptake, enhanced ROS generation, and better biocompatibility, ZnP@Hf-QC mediated PDT exhibited an IC₅₀ of 0.14 μM and achieved exceptional antitumor efficacy with >99% tumor growth inhibition and 80% cure rates on two murine colon cancer models.

Preparation of zinc phthalocyanine-loaded amphiphilic phosphonium chitosan nanomicelles for enhancement of photodynamic therapy efficacy

To increase the solubility and the encapsulation of zinc phthalocyanine (ZnPc) photosensitizer for photodynamic therapy (PDT), a positively charged amphiphilic phosphonium chitosan nanomicelle with multi-benzene structure was developed, and its application to PDT was explored. N-acetyl-l-phenylalanine-(4-carboxybutyl) triphenylphosphonium bromide chitosan (CTPB-CS-NAP), a chitosan derivative with tunable amphiphilicity, was synthesized first. ZnPc was encapsulated in CTPB-CS-NAP at the critical micelle concentration (CMC) of 4.898 mg/L by a hydrophobic self-assembly method to form ZnPc-loaded nanomicelles (ZnPc@CTPB-CS-NAP). The method gives the highest encapsulation efficiency and drug loading of 89.4 % and 22.3 %, respectively. ZnPc@CTPB-CS-NAP is stably dispersed in aqueous solution and shows the average particle size of 103±5 nm. PDT experiments suggest the phototoxicity of ZnPc@CTPB-CS-NAP is much higher than that of ZnPc, but no obvious dark cytotoxicity is observed. Our study has provided a new strategy for improving the photodynamic therapy efficacy of hydrophobic photosensitizer by the encapsulation with chitosan derivative carriers.

Recent Advances in Nanotechnology-Based Diagnosis and Treatments of Human Osteosarcoma

Osteosarcoma (OSA) is a type of bone cancer that begins in the cells that form bones.OSA is a rare mesenchymal bone neoplasm derived from mesenchymal stem cells. Genome disorganization, chromosomal modifications, deregulation of tumor suppressor genes, and DNA repair defects are the factors most responsible for OSA development. Despite significant advances in the diagnosing and treatment of OSA, patients' overall survival has not improved within the last twenty years. Lately, advances in modern nanotechnology have spurred development in OSA management and offered several advantages to overcome the drawbacks of conventional therapies. This technology has allowed the practical design of nanoscale devices combined with numerous functional molecules, including tumor-specific ligands, antibodies, anti-cancer drugs, and imaging probes. Thanks to their small sizes, desirable drug encapsulation efficiency, and good bioavailability, functionalized nanomaterials have found wide-spread applications for combating OSA progression. This review invokes the possible utility of engineered nanomaterials in OSA diagnosis and treatment, motivating the researchers to seek new strategies for tackling the challenges associated with it.

Functional titanium dioxide nanoparticle conjugated with phthalocyanine and folic acid as a promising photosensitizer for targeted photodynamic therapy in vitro and in vivo

Photodynamic therapy (PDT) is a promising cancer treatment that can be implemented using various agents. The conventional photosensitizer Al (III) phthalocyanine chloride tetrasulfonic acid (Pc) has limitations of selectivity in tumor targeting, low affinity to cancer cells, and low two-photon absorption. This study presents a novel photosensitizer FA-TiO₂-Pc, which has the TiO₂ nanoparticle conjugated with a tumor targeting agent of folic acid (FA), and Pc. FA-TiO₂-Pc possessed high targeted photodynamic therapeutic activity and excellent biocompatibility. This promising photosensitizer showed high therapeutic drug efficiency in vitro at a low concentration dose and short incubation time under one-photon excitation (OPE). In vivo, when treated with a low dose of FA-TiO₂-Pc and low light irradiation, the tumor growth was depressed in mice bearing HeLa xenograft tumors with minimal side effects. In addition, the two-photon absorption of FA-TiO₂-Pc was also enhanced compared to Pc, proving that FA-TiO₂-Pc system has a great potential to be used for the therapy of the folate receptor positive cancer cells in both OPE-PDT and two-photon excitation (TPE)-PDT agents.

The potential of micelleplexes as a therapeutic strategy for osteosarcoma disease

Osteosarcoma (OS) is a rare aggressive bone, presenting low patient survival rate, high metastasis and relapse occurrence, mostly due to multi-drug resistant cells. To surpass that, the use of nanomedicine for the targeted delivery of genetic material, drugs or both have been extensively researched. In this review, we address the current situation of the disorder and some gene therapy options in the nanomedicine field that have been investigated. Among them, polymeric micelles (PM) are an advantageous therapeutic alternative highly explored for OS, as they allow for the targeted transportation of poorly water-soluble drugs to cancer cells. In addition, micelleplexes are PMs with cationic properties with promising features, such as the possibility for a dual therapy, which have made them an attractive research subject. The aim of this review article is to elucidate the application of a micelleplex formulation encapsulating the underexpressed miRNA145 to achieve an active targeting to OS cells and overcome multi-drug resistance, as a new and viable therapeutic strategy.

Anticancer effect of LS-HB-mediated photodynamic therapy on hepatocellular carcinoma in vitro and in vivo

Photodynamic therapy (PDT) is a relatively safe way for disease diagnosis and treatment that is based on light and photosensitizers. LS-HB is a promising photosensitizer with a light absorption peak of 660 nm.

AIMS

The present study aimed to investigate the anticancer effects of LS-HB-PDT on hepatocellular carcinoma and its underlying molecular mechanism.

METHODS

In the present study, the MTT assay and xenograft tumor model experiment were used to evaluate its anticancer effects as well as its dark toxicity in hepatocellular carcinoma in vitro and in vivo. Reactive oxygen species assay kit was utilized to detect the reactive oxygen species production induced by LS-HB-PDT.

RESULTS

In vitro, the MTT assay results revealed that LS-HB-PDT exhibited significant cytotoxic effects both in a drug- and light dose-dependent manner. The IC₅₀ of LS-HB-PDT on hepatocellular carcinoma cells was 2.685 μg/ml. However, no dark cytotoxicity was observed at the LS-HB concentrations of 0-50 μg/ml, and no light-induced cytotoxicity was observed at the light (660 nm) dosages of 0-40 J/cm². Furthermore, reactive oxygen species could be induced after LS-HB-PDT in a drug- and light dose-dependent manner. In vivo experiment, the tumor inhibition ratio of tumor-bearing nude mice following LS-HB-PDT was enhanced with the drug and light dose increasing. Notably, tumors in 60.0% of mice disappeared after LS-HB-PDT (2 mg/kg; 100 J/cm²), and the tumor inhibition ratio reached 92.3%. Furthermore, the histological results revealed necrosis and thrombus in tumor tissue caused by LS-HB-PDT, which were not observed in the control, drug alone and light alone groups of mice.

CONCLUSIONS

The present study indicated that LS-HB was a promising photosensitizer with excellent anticancer effects and low side effects. LS-HB-PDT induced reactive oxygen species damage in the cells directly and destroyed tumor blood vessels, thus leading to tumor tissue necrosis.

Simple photoreduction of carbon dioxide to formic acid and true quantum yield

There is a need to develop techniques for conversion of carbon dioxide to useful products such as formaldehyde, formic acid, methanol, and hydrocarbons. Carbon dioxide can be converted into these products using either photochemically, electrochemically, thermochemical or hydrogenation by bacteria. Formate is of interest due to the possibility of being used in liquid fuel cells, as an additive in pyrolysis vapors and as a precursor for biological fuels. In this work, conversion of carbon dioxide to formic acid under acidic conditions and formate under basic or neutral conditions was accomplished through photoreduction using an inexpensive setup consisting of titanium dioxide, metal phthalocyanines and inexpensive incandescent sources. The yield of formic acid based on anion chromatography was 1.54%. This work also discusses and presents a true quantum yield determined using chemical actinometry which was near 2.0%. Detailed studies of the photoreduction process showed that the amount of sensitizer, light intensity and pH affect the amount of formate generated.

Nanomedicine in osteosarcoma therapy: Micelleplexes for delivery of nucleic acids and drugs toward osteosarcoma-targeted therapies

Osteosarcoma(OS) represents the main cancer affecting bone tissue, and one of the most frequent in children. In this review we discuss the major pathological hallmarks of this pathology, its current therapeutics, new active biomolecules, as well as the nanotechnology outbreak applied to the development of innovative strategies for selective OS targeting. Small RNA molecules play a role as key-regulator molecules capable of orchestrate different responses in what concerns cancer initiation, proliferation, migration and invasiveness. Frequently associated with lung metastasis, new strategies are urgent to upgrade the therapeutic outcomes and the life-expectancy prospects. Hence, the prominent rise of micelleplexes as multifaceted and efficient structures for nucleic acid delivery and selective drug targeting is revisited here with special emphasis on ligand-mediated active targeting. Future landmarks toward the development of novel nanostrategies for both OS diagnosis and OS therapy improvements are also discussed.

Rational design of block copolymer self-assemblies in photodynamic therapy

Photodynamic therapy is a technique already used in ophthalmology or oncology. It is based on the local production of reactive oxygen species through an energy transfer from an excited photosensitizer to oxygen present in the biological tissue. This review first presents an update, mainly covering the last five years, regarding the block copolymers used as nanovectors for the delivery of the photosensitizer. In particular, we describe the chemical nature and structure of the block copolymers showing a very large range of existing systems, spanning from natural polymers such as proteins or polysaccharides to synthetic ones such as polyesters or polyacrylates. A second part focuses on important parameters for their design and the improvement of their efficiency. Finally, particular attention has been paid to the question of nanocarrier internalization and interaction with membranes (both biomimetic and cellular), and the importance of intracellular targeting has been addressed.

Recent advances of drug delivery nanocarriers in osteosarcoma treatment

Osteosarcoma is the most common primary malignant bone tumor mainly occurred in children and adolescence, and chemotherapy is limited for the side effects and development of drug resistance. Advances in nanotechnology and knowledge of cancer biology have led to significant improvements in developing tumor-targeted drug delivery nanocarriers, and some have even entered clinically application. Delivery of chemotherapeutic agents by functionalized smart nanocarriers could protect the drugs from rapid clearance, prolong the circulating time, and increase the drug concentration at tumor sites, thus enhancing the therapeutic efficacy and reducing side effects. Various drug delivery nanocarriers have been designed and tested for osteosarcoma treatment, but most of them are still at experimental stage, and more further studies are needed before clinical application. In this present review, we briefly describe the types of commonly used nanocarriers in osteosarcoma treatment, and discuss the strategies for osteosarcoma-targeted delivery and controlled release of drugs. The application of nanoparticles in the management of metastatic osteosarcoma is also briefly discussed. The purpose of this article is to present an overview of recent progress of nanoscale drug delivery platforms in osteosarcoma, and inspire new ideas to develop more effective therapeutic options.

Synthesis and evaluation of novel chlorophyll a derivatives as potent photosensitizers for photodynamic therapy

Chlorophyll a exhibits excellent photosensitive activity in photosynthesis. The unstability limited its application as photoensitizer drug in photodynamic therapy. Here a series of novel chlorophyll a degradation products pyropheophorbide-a derivatives were synthesized and evaluated for lung cancer in PDT. These compounds have strong absorption in 660-670 nm with high molar extinction coefficient, and fluorescence emission in 660-675 nm upon excitation with 410-415 nm light. They all have much higher ROS yields than pyropheophorbide-a, and compound 10 was even higher than [3-(1-hexyloxyethyl)]-pyrophoeophorbide a (HPPH). Distinctive phototoxicity was observed in vitro and the inhibition effect was in light dose-dependent and drug dose-dependent style. They can effectively inhibit the growth of lung tumor in vivo. Among them, compound 8 and 11 have outstanding photodynamic anti-tumor effects without obvious skin photo-toxicity, so they can act as new drug candidates for photodynamic therapy.

Photodynamic therapy of cancer with liposomal photosensitizers

The photodynamic reaction involves the light-induced generation of an excited state in a photosensitizer molecule (PS), which then results in the formation of reactive oxygen species in the presence of oxygen, or a direct modification of a cellular molecule. Most PSs are porphyrinoids, which are highly lipophilic, and are administered usually in liposomes to facilitate their effective delivery to target cells. The currently available liposomal formulations are Visudyne^® and Fospeg^®. Novel PSs were developed and tested for their photodynamic activity against cancer cells. Several compounds were highly phototoxic to oral cancer cells both in free and liposome-encapsulated form, with nanomolar IC₅₀ values. The lowest IC₅₀s (7-13 nM) were obtained with a PS encapsulated in cationic liposomes.

Zinc(II) phthalocyanines as photosensitizers for antitumor photodynamic therapy

Photodynamic therapy (PDT) is a highly specific and clinically approved method for cancer treatment in which a nontoxic drug known as photosensitizer (PS) is administered to a patient. After selective tumor irradiation, an almost complete eradication of the tumor can be reached as a consequence of reactive oxygen species (ROS) generation, which not only damage tumor cells, but also lead to tumor-associated vasculature occlusion and the induction of an immune response. Despite exhaustive investigation and encouraging results, zinc(II) phthalocyanines (ZnPcs) have not been approved as PSs for clinical use yet. This review presents an overview on the physicochemical properties of ZnPcs and biological results obtained both in vitro and in more complex models, such as 3D cell cultures, chicken chorioallantoic membranes and tumor-bearing mice. Cell death pathways induced after PDT treatment with ZnPcs are discussed in each case. Finally, combined therapeutic strategies including ZnPcs and the currently available clinical trials are mentioned.

Theoretical and experimental studies concerning monomer/aggregates equilibrium of zinc phthalocyanine for future photodynamic action

Monomeric zinc phthalocyanine has been studied as a promising active photosensitizer in photodynamic therapy against cancer, in which its aggregate form is non-active. This paper aimed to describe the monomer/aggregates equilibrium of zinc phthalocyanine in binary water/DMSO mixtures. To reach this aim theoretical calculation, electronic absorption, static and time-resolved fluorescence, and resonance light scattering was used. Zinc phthalocyanine shows a complex water dependence behavior in the mixture. At least three distinct steps were observed: (i) until 30% water zinc phthalocyanine is essentially in the monomeric form, changing to (ii) small slipped cofacial-aggregates around 30% to 40% water and finally to (iii) a staircase arrangement of large aggregates at higher water percent. The staircase arrangement is driven by the intermolecular coordination between the pyrrolic nitrogen lone-pairs and the central metal zinc. The water-Zn coordination governs the fluorescence quenching by a static mechanism. These results have direct relevance in the better understanding on the behavior of zinc phthalocyanine in vivo and when incorporated in drug delivery systems for clinical applications in photodynamic therapy.

Adjuvant Biophysical Therapies in Osteosarcoma

Osteosarcoma (OS) is a primary bone sarcoma, manifesting as osteogenesis by malignant cells. Nowadays, patients’ quality of life has been improved, however continuing high rates of limb amputation, pulmonary metastasis and drug toxicity, remain unresolved issues. Thus, effective osteosarcoma therapies are still required. Recently, the potentialities of biophysical treatments in osteosarcoma have been evaluated and seem to offer a promising future, thanks in this field as they are less invasive. Several approaches have been investigated such as hyperthermia (HT), high intensity focused ultrasound (HIFU), low intensity pulsed ultrasound (LIPUS) and sono- and photodynamic therapies (SDT, PDT). This review aims to summarize in vitro and in vivo studies and clinical trials employing biophysical stimuli in osteosarcoma treatment. The findings underscore how the technological development of biophysical therapies might represent an adjuvant role and, in some cases, alternative role to the surgery, radio and chemotherapy treatment of OS. Among them, the most promising are HIFU and HT, which are already employed in OS patient treatment, while LIPUS/SDT and PDT seem to be particularly interesting for their low toxicity.

Double stimuli-responsive polysaccharide block copolymers as green macrosurfactants for near-infrared photodynamic therapy

The NIR absorbing photosensitizer phthalocyanine zinc (PC(Zn)) was stabilized in aqueous media as water-dispersible nanoparticles with a reduction- and pH-responsive full polysaccharide block copolymer. A cellular uptake and also photo switchable intracellular activity of the cargo upon irradiation at wavelengths in the near infrared region were shown. The block copolymer was synthesized by applying a copper-free click strategy based on a thiol exchange reaction, creating an amphiphilic double-stimuli-responsive mixed disulfide. The dual-sensitive polysaccharide micelles represent a non-toxic and biodegradable green macrosurfactant for the delivery of phthalocyanine zinc. By encapsulation into micellar nanoparticles, the bioavailability of PC(Zn) increased significantly, enabling smart photodynamic therapy for future applications in cancer-related diseases.

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.