Photodynamic therapy mediated by aluminium-phthalocyanine nanoemulsion eliminates primary tumors and pulmonary metastases in a murine 4T1 breast adenocarcinoma model

Development of Liposomes Loaded with Chloroaluminum Phthalocyanine for Application of Photodynamic Therapy in Breast Cancer

Chloraluminium phthalocyanine (ClAlPc) has potential therapeutic effect for the treatment of cancer; however, the molecule is lipophilic and may present self-aggregation which limits its clinical success. Thus, nanocarriers like liposomes can improve ClAlPc solubility, reduce off-site toxicity and increase circulation time. For this purpose, developing suitable liposomes requires the evaluation of different lipid compositions. Herein, we aimed to develop liposomes containing soy phosphatidylcholine (SPC), 1,2-distearoyl-sn-glycero- 3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPEPEG2000), cholesterol and oleic acid loaded with ClAlPc using the surface response methodology and the Box-Behnken design. Liposomes with particle size from 110.93 to 374.97 nm and PdI from 0.265 to 0.468 were obtained. The optimized formulation resulted in 69.09 % of ClAlPc encapsulated, with particle size and polydispersity index, respectively, at 153.20 nm and 0.309, providing stability and aggregation control. Atomic force microscopy revealed vesicles in a spherical or almost spherical shape, while the analyzes by Differential Scanning Calorimetry (DSC), Powder X-ray Diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR) suggested that the drug was adequately incorporated into the lipid bilayer of liposomes, in its amorphous state or molecularly dispersed. In vitro studies conducted in breast cancer cells (4T1) showed that liposome improved phototoxicity compared to the ClAlPc solution. ClAlPc-loaded liposomes also enhanced the production of ROS 3-fold compared to the ClAlPc solution. Finally, confocal microscopy and flow cytometry demonstrated the ability of the liposomes to enter cells and deliver the fluorescent ClAlPc photosensitizer with dose and time-dependent effects. Thus, this work showed that Box-Behnken factorial design was an effective strategy for optimizing formulation development. The obtained ClAlPc liposomes can be applied for photodynamic therapy in breast cancer cells.

Comparing PVP and Polymeric Micellar Formulations of a PEGylated Photosensitizing Phthalocyanine by NMR and Optical Techniques

Phthalocyanines are ideal candidates as photosensitizers for photodynamic therapy (PDT) of cancer due to their favorable chemical and photophysical properties. However, their tendency to form aggregates in water reduces PDT efficacy and poses challenges in obtaining efficient forms of phthalocyanines for therapeutic applications. In the current work, polyvinylpyrrolidone (PVP) and micellar formulations were compared for encapsulating and monomerizing a water-soluble zinc phthalocyanine bearing four non-peripheral triethylene glycol chains (Pc1). 1H NMR spectroscopy combined with UV-vis absorption and fluorescence spectroscopy revealed that Pc1 exists as a mixture of regioisomers in monomeric form in dimethyl sulfoxide but forms dimers in an aqueous buffer. PVP, polyethylene glycol castor oil (Kolliphor RH40), and three different triblock copolymers with varying proportions of polyethylene and polypropylene glycol units (termed P188, P84, and F127) were tested as micellar carriers for Pc1. 1H NMR chemical shift analysis, diffusion-ordered spectroscopy, and 2D nuclear Overhauser enhancement spectroscopy was applied to monitor the encapsulation and localization of Pc1 at the polymer interface. Kolliphor RH40 and F127 micelles exhibited the highest affinity for encapsulating Pc1 in the micellar core and resulted in intense Pc1 fluorescence emission as well as efficient singlet oxygen formation along with PVP. Among the triblock copolymers, efficiency in binding and dimer dissolution decreased in the order F127 > P84 > P188. PVP was a strong binder for Pc1. However, Pc1 molecules are rather surface-attached and exist as monomer and dimer mixtures. The results demonstrate that NMR combined with optical spectroscopy offer powerful tools to assess parameters like drug binding, localization sites, and dynamic properties that play key roles in achieving high host-guest compatibility. With the corresponding adjustments, polymeric micelles can offer simple and easily accessible drug delivery systems optimizing phthalocyanines' properties as efficient photosensitizers.

Understanding the Photodynamic Therapy Induced Bystander and Abscopal Effects: A Review

Photodynamic therapy (PDT) is a clinically approved minimally/non-invasive treatment modality that has been used to treat various conditions, including cancer. The bystander and abscopal effects are two well-documented significant reactions involved in imparting long-term systemic effects in the field of radiobiology. The PDT-induced generation of reactive oxygen and nitrogen species and immune responses is majorly involved in eliciting the bystander and abscopal effects. However, the results in this regard are unsatisfactory and unpredictable due to several poorly elucidated underlying mechanisms and other factors such as the type of cancer being treated, the irradiation dose applied, the treatment regimen employed, and many others. Therefore, in this review, we attempted to summarize the current knowledge regarding the non-targeted effects of PDT. The review is based on research published in the Web of Science, PubMed, Wiley Online Library, and Google Scholar databases up to June 2023. We have highlighted the current challenges and prospects in relation to obtaining clinically relevant robust, reproducible, and long-lasting antitumor effects, which may offer a clinically viable treatment against tumor recurrence and metastasis. The effectiveness of both targeted and untargeted PDT responses and their outcomes in clinics could be improved with more research in this area.

Photodynamic Therapy: From the Basics to the Current Progress of N-Heterocyclic-Bearing Dyes as Effective Photosensitizers

Photodynamic therapy, an alternative that has gained weight and popularity compared to current conventional therapies in the treatment of cancer, is a minimally invasive therapeutic strategy that generally results from the simultaneous action of three factors: a molecule with high sensitivity to light, the photosensitizer, molecular oxygen in the triplet state, and light energy. There is much to be said about each of these three elements; however, the efficacy of the photosensitizer is the most determining factor for the success of this therapeutic modality. Porphyrins, chlorins, phthalocyanines, boron-dipyrromethenes, and cyanines are some of the N-heterocycle-bearing dyes' classes with high biological promise. In this review, a concise approach is taken to these and other families of potential photosensitizers and the molecular modifications that have recently appeared in the literature within the scope of their photodynamic application, as well as how these compounds and their formulations may eventually overcome the deficiencies of the molecules currently clinically used and revolutionize the therapies to eradicate or delay the growth of tumor cells.

Nanomaterials in tumor immunotherapy: new strategies and challenges

Tumor immunotherapy exerts its anti-tumor effects by stimulating and enhancing immune responses of the body. It has become another important modality of anti-tumor therapy with significant clinical efficacy and advantages compared to chemotherapy, radiotherapy and targeted therapy. Although various kinds of tumor immunotherapeutic drugs have emerged, the challenges faced in the delivery of these drugs, such as poor tumor permeability and low tumor cell uptake rate, had prevented their widespread application. Recently, nanomaterials had emerged as a means for treatment of different diseases due to their targeting properties, biocompatibility and functionalities. Moreover, nanomaterials possess various characteristics that overcome the defects of traditional tumor immunotherapy, such as large drug loading capacity, precise tumor targeting and easy modification, thus leading to their wide application in tumor immunotherapy. There are two main classes of novel nanoparticles mentioned in this review: organic (polymeric nanomaterials, liposomes and lipid nanoparticles) and inorganic (non-metallic nanomaterials and metallic nanomaterials). Besides, the fabrication method for nanoparticles, Nanoemulsions, was also introduced. In summary, this review article mainly discussed the research progress of tumor immunotherapy based on nanomaterials in the past few years and offers a theoretical basis for exploring novel tumor immunotherapy strategies in the future.

ALA-PDT regulates macrophage M1 polarization via ERK/MAPK-NLRP3 pathway to promote the early inflammatory response

BACKGROUND

Photodynamic therapy (PDT) is a promising new approach to promote wound healing and its effectiveness has been demonstrated in both clinical and animal studies. Macrophages are the key cells in wound healing and inflammatory response. However, the mechanism of action of PDT on macrophages in promoting wound healing is still unclear.

METHODS

In this study, RAW264.7 cells were used. We analyzed the expression levels of macrophage markers arginase 1 (Arg-1), CD206, iNOS, CD86, and inflammatory factors IL-6, TNF-α, and IL-1β by reverse transcription-polymerase chain reaction and Western blot, Milliplex microtubule-associated protein multiplex assay was performed to analyze the expression of inflammatory factors in the supernatant. Live cell Imaging System to observe the dynamic process of macrophage phagocytosis. Western blot was performed to observe the activation of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and NOD-like receptor protein 3 (NLRP3) inflammasome.

RESULTS

5-Aminolevulinic acid (ALA)-PDT increased the expression of M1 marker iNOS/CD86 and decreased the expression of Arg-1/CD206 in RAW264.7 cells, while, proinflammatory factors IL-6, TNF-α, and IL-1β expression was enhanced and macrophage phagocytosis was increased. We also found that these phenomena were associated with activation of the ERK/MAPK-NLRP3 pathway.

CONCLUSION

ALA-PDT promotes early inflammatory responses by regulating macrophage M1 polarization through the ERK/MAPK-NLRP3 pathway. It also promotes macrophage phagocytosis.

Nanoemulsion applications in photodynamic therapy

Nanoemulsion, or nanoscaled-size emulsions, is a thermodynamically stable system formed by blending two immiscible liquids, blended with an emulsifying agent to produce a single phase. Nanoemulsion science has advanced rapidly in recent years, and it has opened up new opportunities in a variety of fields, including pharmaceuticals, biotechnology, food, and cosmetics. Nanoemulsion has been recognized as a potential drug delivery technology for various drugs, such as photosensitizing agents (PS). In photodynamic therapy (PDT), PSs produce cytotoxic reactive oxygen species under specific light irradiation, which oxidize the surrounding tissues. Over the past decades, the idea of PS-loaded nanoemulsions has received researchers' attention due to their ability to overcome several limitations of common PSs, such as limited permeability, non-specific phototoxicity, hydrophobicity, low bioavailability, and self-aggregation tendency. This review aims to provide fundamental knowledge of nanoemulsion formulations and the principles of PDT. It also discusses nanoemulsion-based PDT strategies and examines nanoemulsion advantages for PDT, highlighting future possibilities for nanoemulsion use.

Applications of lipid-engineered nanoplatforms in the delivery of various cancer therapeutics to surmount breast cancer

Breast cancer (BC) is the most extensively accounted malignancy among the women across the globe and is treatable in 70-80% of patients with early-stage, non-metastatic cancer. The current available therapies have been found to be less effective to treat distant organ metastases and advanced breast cancers. The clinical efficacy hugely suffers from chemoresistance, non-specific toxicity, relapse and other associated adverse effects. Furthermore, lack of controlled delivery and effective temporospatial presence of chemotherapeutics has resulted in suboptimal therapeutic response. Nanotechnology based approaches have been widely used over the period as they are nanometric, offer controlled and site-specific drug release along with reduced toxicity, improved half-life, and stability. Lipid-based nanoplatforms have grabbed a tremendous attention for delivering cancer therapeutics as they are cost-effective, scalable and provide better entrapment efficiency. In this review, all the promising applications of lipid-engineered nanotechnological tools for breast cancer will be summarized and discussed. Subsequently, BC therapy achieved with the aid of chemotherapeutics, phytomedicine, genes, peptides, photosensitizers, diagnostic and immunogenic agents etc. will be reviewed and discussed. This review gives tabular information on all the results obtained pertaining to the physicochemical properties of the lipidic nanocarrier, in vitro studies conferring to mechanistic drug release profile, cell viability, cellular apoptosis and in vivo studies referring to cellular internalisation, reduction of tumor volume, PK-PD profile, bioavailability achieved and anti-tumor activity in detail. It also gives complete information on the most relevant clinical trials done on lipidic nanoplatforms over two decades in tabular form. The review highlights the current status and future prospects of lipidic nanoplatforms with streamlined focus on cancer nanotherapeutics.

Induction of Immunogenic Cell Death by Photodynamic Therapy Mediated by Aluminum-Phthalocyanine in Nanoemulsion

Photodynamic therapy (PDT) has been clinically employed to treat mainly superficial cancer, such as basal cell carcinoma. This approach can eliminate tumors by direct cytotoxicity, tumor ischemia, or by triggering an immune response against tumor cells. Among the immune-related mechanisms of PDT, the induction of immunogenic cell death (ICD) in target cells is to be cited. ICD is an apoptosis modality distinguished by the emission of damage-associated molecular patterns (DAMP). Therefore, this study aimed to analyze the immunogenicity of CT26 and 4T1 treated with PDT mediated by aluminum-phthalocyanine in nanoemulsion (PDT-AlPc-NE). Different PDT-AlPc-NE protocols with varying doses of energy and AlPc concentrations were tested. The death mechanism and the emission of DAMPs-CRT, HSP70, HSP90, HMGB1, and IL-1β-were analyzed in cells treated in vitro with PDT. Then, the immunogenicity of these cells was assessed in an in vivo vaccination-challenge model with BALB/c mice. CT26 and 4T1 cells treated in vitro with PDT mediated by AlPc IC₅₀ and a light dose of 25 J/cm² exhibited the hallmarks of ICD, i.e., these cells died by apoptosis and exposed DAMPs. Mice injected with these IC₅₀ PDT-treated cells showed, in comparison to the control, increased resistance to the development of tumors in a subsequent challenge with viable cells. Mice injected with 4T1 and CT26 cells treated with higher or lower concentrations of photosensitizer and light doses exhibited a significantly lower resistance to tumor development than those injected with IC₅₀ PDT-treated cells. The results presented in this study suggest that both the photosensitizer concentration and light dose affect the immunogenicity of the PDT-treated cells. This event can affect the therapy outcomes in vivo.

AlPc/ZnPc-based oncological photodynamic therapy for a selective eradication of leukemic cells from ovarian tissue

Due to the risk of reintroducing malignant cells, autotransplantation of cryopreserved ovarian tissue is not allowed in leukemia patients. In order to restore fertility in these patients, ex vivo purging of ovarian fragments could be proposed as a strategy to eradicate malignant cells before grafting. Photodynamic therapy (PDT), as a clinical-approved modality, is a minimally invasive and selective therapeutic for eliminating malignant cells. The present work aims therefore to evaluate the phototoxicity of two photosensitizers (aluminum phthalocyanine (AlPc) and zinc phthalocyanine (ZnPc)) on leukemia cells. To this end, two lines of malignant cells (K562 and HL-60) and isolated ovarian stromal cells (control) were treated by PDT using a diode laser with various energy densities. Cell viability after the treatment, the amount of generated reactive oxygen species, dark toxicity of the photosensitizers, and single-cell morphology were studied. Our results demonstrated that using irradiation with the energy density of 10 J/cm², 1 µM AlPc could significantly reduce the viability of K562 (4.73 ± 0.14%) and HL-60 (2.74 ± 0.31%). Similarly, the viability of these cells was reduced (K562 cells: 3.84 ± 0.81%; HL-60 cells: 6.82 ± 3.21%) with 1 µM ZnPc and an energy density of 50 J/cm². On the other hand, these PDT protocols had no significant effect on stromal cells. These findings indicate that our approach can be a promising strategy for the safe restoration of fertility in leukemia patients. However, further studies are necessary to assess its efficiency in ovarian fragments containing malignant cells to determine their eradication rate and the effect of our treatment on the survival of stromal cells and preantral follicles.

Aluminium (III) phthalocyanine chloride tetrasulphonate is an effective photosensitizer for the eradication of lung cancer stem cells

Cancer stem cells (CSCs) are considered to contribute to the recurrence of lung cancer due to their stem-like nature and the involvement of genetic markers associated with drug efflux, regeneration and metastases. Photodynamic therapy (PDT) is a cost-effective and non-invasive therapeutic application that can act as an alternative therapy for lung cancer when considering CSC involvement. Stem-like cells derived from the A549 lung cancer cell line, positive for CD133, CD56 and CD44 antigen markers, were characterized, intracellular localization of aluminium (III) phthalocyanine chloride tetrasulphonate (AlPcS₄Cl) determined and its anti-cancer PDT effects were evaluated. Results confirmed that isolated cells were stem cell-like and subcellular localization of AlPcS₄Cl in integral organelles involved in cell homeostasis supported the destruction of CSC. AlPcS₄Cl's effectivity was demonstrated with CSC eradication showing a significant increase in cytotoxicity and cell death via apoptosis, caused by a decrease in mitochondrial membrane potential. PDT could serve as a palliative treatment for lung cancer and improve prognosis by elimination of lung CSCs.

Synergistic effect of photobiomodulation and phthalocyanine photosensitizer on fibroblast signaling responses in an in vitro three-dimensional microenvironment

Photobiomodulation (PBM) is a promising medical treatment modality in the area of photodynamic therapy (PDT). In this study, we investigated the effect of combined therapy in a 3D microenvironment using aluminum chloride phthalocyanines (AlClPc) as the photosensitizing agent. Normal human fibroblast-containing collagen biomatrix was prepared and treated with an oil-in-water (o/a) AlClPc-loaded nanoemulsion (from 0.5 to 3.0 μM) and irradiated at a range of fluences (from 0.1 to 3.0 J/cm²) using a continuous-wave light-emitting diode (LED) irradiation system (660 nm). PBM at 1.2 J/cm² and AlClPc/NE at 0.5 μM modified the fibroblast signaling response under 3D conditions, promoting collagen synthesis, ROS production, MMP-9 secretion, proliferation of the actin network, and facile myofibroblastic differentiation. PBM alone (at 1.2 J/cm² and 0.3 J/cm²) had no significant effect on any of these parameters. The combined therapy affected myofibroblastic differentiation, inflammatory response, and extracellular matrix pliability, and should thus be examined further in subsequent studies considering that no side effects of PBM have been reported. Even though significant progress has been made in the field of phototherapy in recent years, it is necessary to further elucidate the detailed mechanisms underlying its effects already shown in 2D conditions to increase the acceptance of this beneficial and non-invasive therapeutic approach.

Potential of Cyanine Derived Dyes in Photodynamic Therapy

Photodynamic therapy (PDT) is a method of cancer treatment that leads to the disintegration of cancer cells and has developed significantly in recent years. The clinically used photosensitizers are primarily porphyrin, which absorbs light in the red spectrum and their absorbance maxima are relatively short. This review presents group of compounds and their derivatives that are considered to be potential photosensitizers in PDT. Cyanine dyes are compounds that typically absorb light in the visible to near-infrared-I (NIR-I) spectrum range (750-900 nm). This meta-analysis comprises the current studies on cyanine dye derivatives, such as indocyanine green (so far used solely as a diagnostic agent), heptamethine and pentamethine dyes, squaraine dyes, merocyanines and phthalocyanines. The wide array of the cyanine derivatives arises from their structural modifications (e.g., halogenation, incorporation of metal atoms or organic structures, or synthesis of lactosomes, emulsions or conjugation). All the following modifications aim to increase solubility in aqueous media, enhance phototoxicity, and decrease photobleaching. In addition, the changes introduce new features like pH-sensitivity. The cyanine dyes involved in photodynamic reactions could be incorporated into sets of PDT agents.

The role of Cryptococcus neoformans histone deacetylase genes in the response to antifungal drugs, epigenetic modulators and to photodynamic therapy mediated by an aluminium phthalocyanine chloride nanoemulsion in vitro

Cryptococcus is a globally distributed fungal pathogen that primarily afflicts immunocompromised individuals. The therapeutic options are limited and include mostly amphotericin B or fluconazole, alone or in combination. The extensive usage of antifungals allowed the selection of resistant pathogens posing threats to global public health. Histone deacetylase genes are involved in Cryptococcus virulence, and in pathogenicity and resistance to azoles in Candida albicans. Aiming to assess whether histone deacetylase genes are involved in antifungal response and in synergistic drug interactions, we evaluated the activity of amphotericin B, fluconazole, sulfamethoxazole, sodium butyrate or trichostatin A (histone deacetylase inhibitors), and hydralazine or 5- aza-2'-deoxycytidine (DNA methyl-transferase inhibitors) against different Cryptococcus neoformans strains, C. neoformans histone deacetylase null mutants and Cryptococcus gattii NIH198. The drugs were employed alone or in different combinations. Fungal growth after photodynamic therapy mediated by an aluminium phthalocyanine chloride nanoemulsion, alone or in combination with the aforementioned drugs, was assessed for the C. neoformans HDAC null mutant strains. Our results showed that fluconazole was synergistic with sodium butyrate or with trichostatin A for the hda1Δ/hos2Δ double mutant strain. Sulfamethoxazole was synergistic with sodium butyrate or with hydralazine also for hda1Δ/hos2Δ. These results clearly indicate a link between HDAC impairment and drug sensitivity. Photodynamic therapy efficacy on controlling the growth of the HDAC mutant strains was increased by amphotericin B, fluconazole, sodium butyrate or hydralazine. This is the first study in Cryptococcus highlighting the combined effects of antifungal drugs, histone deacetylase or DNA methyltransferase inhibitors and photodynamic therapy in vitro.

Combined paclitaxel-doxorubicin liposomal results in positive prognosis with infiltrating lymphocytes in lung metastasis

Aim: To investigate the effect of liposomes containing the classical cytotoxic drugs paclitaxel and doxorubicin (Lipo-Pacli/Dox), against a metastatic breast cancer model. We also investigated if Lipo-Pacli/Dox was capable of reverting the tolerogenic environment of metastatic lesions. Materials & methods: Immunogenic cell death induction by the Pacli/Dox combination was assessed in vitro. Antitumor activity and in vivo safety of Lipo-Pacli/Dox were evaluated using a 4T1 breast cancer mouse model Results: Lipo-Pacli/Dox, with a size of 189 nm and zeta potential of -5.01 mV, promoted immune system activation and partially controlled the progression of pulmonary metastasis. Conclusion: Lipo-Pacli/Dox was useful to control both primary tumor and lung metastasis in breast cancer (4T1) mice model. Additionally, Lipo-Pacli/Dox acts as an immunological modulator for this metastatic breast cancer model.

Perspectives of photodynamic therapy in biotechnology

Photodynamic therapy (PDT) is a current and innovative technique that can be applied in different areas, such as medical, biotechnological, veterinary, among others, both for the treatment of different pathologies, as well as for diagnosis. It is based on the action of light to activate photosensitizers that will perform their activity on target tissues, presenting high sensitivity and less adverse effects. Therefore, knowing that biotechnology aims to use processes to develop products aimed at improving the quality of life of human and the environment, and optimizing therapeutic actions, researchers have been used PDT as a tool of choice. This review aims to identify the impacts and perspectives and challenges of PDT in different areas of biotechnology, such as health and agriculture and oncology. Our search demonstrated that PDT has an important impact around oncology, minimizing the adverse effects and resistance to chemotherapeutic to the current treatments available for cancer. Veterinary medicine is another area with continuous interest in this therapy, since studies have shown promising results for the treatment of different animal pathologies such as Bovine mastitis, Malassezia, cutaneous hemangiosarcoma, among others. In agriculture, PDT has been used, for example, to remove traces of antibiotics of milk. The challenges, in general, of PDT in the field of biotechnology are mainly the development of effective and non-toxic or less toxic photosensitizers for humans, animals and plants. We believe that there is a current and future potential for PDT in different fields of biotechnology due to the existing demand.