Antitumor Effect of Photodynamic Therapy/Sonodynamic Therapy/Sono-Photodynamic Therapy of Chlorin e6 and Other Applications

A Bioinspired Immunostimulatory System for Inducing Powerful Antitumor Immune Function by Directly Causing Plasma Membrane Rupture

The Gasdermin protein is a membrane disruptor that can mediate immunogenic pyroptosis and elicit anti-tumor immune function. However, cancer cells downregulate Gasdermin and develop membrane repair mechanisms to resist pyroptosis. Therefore, an artificial membrane disruptor (AMD) that can directly mediate membrane rupture in pyroptosis-deficient cells and induce antitumor immune responses in a controllable manner will be valuable in preclinical and clinical research. A micron-scale Ce6-based AMD that can directly induce plasma membrane rupture (PMR) in gasdermin-deficient tumor cells is established. Micron-scale AMDs localize Ce6 specifically to the plasma membrane without labeling other organelles. Compared to free Ce6 molecules, the use of AMDs results in a higher degree of specificity for the plasma membrane. Due to this specificity, AMDs mediate fast and irreversible PMR under 660 nm red light. Furthermore, the AMDs are capable of inducing programmed cell death and lytic cell death in a catalytic manner, demonstrating that the amount of Ce6 used by AMDs is only one-fifth of that used by Ce6 alone when inducing 80% of cancer cell death. In vivo, the AMDs show specificity for tumor targeting and penetration, suggesting that light-driven programmed cell death is specific to tumors. AMDs are applied to antitumor therapy in gasdermin-deficient tumors, resulting in efficient tumor elimination with minimal damage to major organs when combined with anti-PD-1 therapy. Tumor regression is correlated with PMR-mediated inflammation and T-cell-based immune responses. This study provides new insights for designing bioinspired membrane disruptors for PMR and mediating anti-tumor immunotherapy. Additionally, AMD is a dependable tool for examining the immunogenicity of PMR both in vitro and in vivo.

Natural-product-based, carrier-free, noncovalent nanoparticles for tumor chemo-photodynamic combination therapy

Cancer, with its diversity, heterogeneity, and complexity, is a significant contributor to global morbidity, disability, and mortality, highlighting the necessity for transformative treatment approaches. Photodynamic therapy (PDT) has aroused continuous interest as a viable alternative to conventional cancer treatments that encounter drug resistance. Nanotechnology has brought new advances in medicine and has shown great potential in drug delivery and cancer treatment. For precise and efficient therapeutic utilization of such a tumor therapeutic approach with high spatiotemporal selectivity and minimal invasiveness, the carrier-free noncovalent nanoparticles (NPs) based on chemo-photodynamic combination therapy is essential. Utilizing natural products as the foundation for nanodrug development offers unparalleled advantages, including exceptional pharmacological activity, easy functionalization/modification, and well biocompatibility. The natural-product-based, carrier-free, noncovalent NPs revealed excellent synergistic anticancer activity in comparison with free photosensitizers and free bioactive natural products, representing an alternative and favorable combination therapeutic avenue to improve therapeutic efficacy. Herein, a comprehensive summary of current strategies and representative application examples of carrier-free noncovalent NPs in the past decade based on natural products (such as paclitaxel, 10-hydroxycamptothecin, doxorubicin, etoposide, combretastatin A4, epigallocatechin gallate, and curcumin) for tumor chemo-photodynamic combination therapy. We highlight the insightful design and synthesis of the smart carrier-free NPs that aim to enhance PDT efficacy. Meanwhile, we discuss the future challenges and potential opportunities associated with these NPs to provide new enlightenment, spur innovative ideas, and facilitate PDT-mediated clinical transformation.

Phototoxicity in vitro and safety in vivo of the emulsion photosensitizer based on furanocoumarins of Heracleum sosnowskyi

The use of plants such as giant hogweed as raw materials for the manufacture of dosage forms has been little explored. In this study, we utilized furanocoumarins from the Heracleum sosnowskyi plant to create an experimental emulsion dosage form (EmFHS). The EmFHS was finely dispersed (481.8 nm ± 71.1 nm), shelf-stable, and contained predominantly 8-methoxypsoralen at a concentration of 1 mg/ml. Phototoxicity analysis of EmFHS for THP-1 cells under UV (365 nm) irradiation showed an IC50 of 19.1 µg/ml (24 h) and 6.3 µg/ml (48 h). In relation to spheroids (L929), EmFHS exhibited a phototoxic effect in the concentration range of 31.25-125 µg/ml8-MOP. A full phototoxic effect was observed 48 h after UV irradiation. The phototoxic effect of EmFHS in vitro was dose-dependent and comparable to the effect of emulsion synthetic 8-methoxypsoralen and chlorin e6 solution. EmFHS cytotoxicity was caused solely by UV radiation, and toxicity in the dark was minimal. EmFHS, administered at a dose of 3 mg/kg8-MOP, was found to be safe after a single intravenous administration to rats. It had a photosensitizing effect in the form of local photodermatitis when exposed to UV irradiation at a dose of 44 J/cm2. The biokinetics of emulsion furanocoumarins showed that the phototoxic effect of EmFHS is due to the high penetration ability of the emulsion into cells of spheroids. At the same time, it has a low degree of cumulation when administered intravenously. The obtained data suggest that EmFHS may be a promising treatment for PUVA therapy of various dermatological diseases. Additionally, the plant Heracleum sosnowskyi shows potential as a basis for creating new dosage forms with phototherapeutic effects.

Therapeutic Applications of Nanomedicine: Recent Developments and Future Perspectives

The concept of nanomedicine has evolved significantly in recent decades, leveraging the unique phenomenon known as the enhanced permeability and retention (EPR) effect. This has facilitated major advancements in targeted drug delivery, imaging, and individualized therapy through the integration of nanotechnology principles into medicine. Numerous nanomedicines have been developed and applied for disease treatment, with a particular focus on cancer therapy. Recently, nanomedicine has been utilized in various advanced fields, including diagnosis, vaccines, immunotherapy, gene delivery, and tissue engineering. Multifunctional nanomedicines facilitate concurrent medication delivery, therapeutic monitoring, and imaging, allowing for immediate responses and personalized treatment plans. This review concerns the major advancement of nanomaterials and their potential applications in the biological and medical fields. Along with this, we also mention the various clinical translations of nanomedicine and the major challenges that nanomedicine is currently facing to overcome the clinical translation barrier.

Cascade Nanoreactor Employs Mitochondrial-Directed Chemodynamic and δ-ALA-Mediated Photodynamic Synergy for Deep-Seated Oral Cancer Therapy

The management of oral squamous cell carcinoma (OSCC) poses significant challenges, leading to organ impairment and ineffective treatment of deep-seated tumors, adversely affecting patient prognosis. A cascade nanoreactor that integrates photodynamic therapy (PDT) and chemodynamic therapy (CDT) for comprehensive multimodal OSCC treatment is introduced. Utilizing iron oxide and mesoporous silica, the FMMSH drug delivery system, encapsulating the photosensitizer prodrug δ-aminolevulinic acid (δ-ALA), is developed. Triphenylphosphine (TPP) modification facilitates mitochondrial targeting, while tumor cell membrane (TCM) coating provides homotypic targeting. The dual-targeting δ-ALA@FMMSH-TPP-TCM demonstrate efficacy in eradicating both superficial and deep tumors through synergistic PDT/CDT. Esterase overexpression in OSCC cells triggers δ-ALA release, and excessive hydrogen peroxide in tumor mitochondria undergoes Fenton chemistry for CDT. The synergistic interaction of PDT and CDT increases cytotoxic ROS levels, intensifying oxidative stress and enhancing apoptotic mechanisms, ultimately leading to tumor cell death. PDT/CDT-induced apoptosis generates δ-ALA-containing apoptotic bodies, enhancing antitumor efficacy in deep tumor cells. The anatomical accessibility of oral cancer emphasizes the potential of intratumoral injection for precise and localized treatment delivery, ensuring focused therapeutic agent delivery to maximize efficacy while minimizing side effects. Thus, δ-ALA@FMMSH-TPP-TCM, tailored for intratumoral injection, emerges as a transformative modality in OSCC treatment.

Advances in Nanodynamic Therapy for Cancer Treatment

Nanodynamic therapy (NDT) exerts its anti-tumor effect by activating nanosensitizers to generate large amounts of reactive oxygen species (ROS) in tumor cells. NDT enhances tumor-specific targeting and selectivity by leveraging the tumor microenvironment (TME) and mechanisms that boost anti-tumor immune responses. It also minimizes damage to surrounding healthy tissues and enhances cytotoxicity in tumor cells, showing promise in cancer treatment, with significant potential. This review covers the research progress in five major nanodynamic therapies: photodynamic therapy (PDT), electrodynamic therapy (EDT), sonodynamic therapy (SDT), radiodynamic therapy (RDT), and chemodynamic therapy (CDT), emphasizing the significant role of advanced nanotechnology in the development of NDT for anti-tumor purposes. The mechanisms, effects, and challenges faced by these NDTs are discussed, along with their respective solutions for enhancing anti-tumor efficacy, such as pH response, oxygen delivery, and combined immunotherapy. Finally, this review briefly addresses challenges in the clinical translation of NDT.

Monitoring of singlet oxygen generation of a novel Schiff-base substituted silicon phthalocyanines by sono-photochemical studies and in vitro activities on prostate cancer cell

This study demonstrates the potential of sono-photodynamic therapy as an effective approach for enhancing singlet oxygen generation using the synthesized Schiff-base diaxially substituted silicon phthalocyanines. In photochemical studies, the singlet oxygen quantum yields (Φ∆) were determined as 0.43 for Si1a, 0.94 for Q-Si1a, 0.58 for S-Si1a, and 0.49 for B-Sia1. In sono-photochemical studies, the Φ∆ values were reached to 0.67 for Si1a, 1.06 for Q-Si1a, 0.65 for S-Si1a, and 0.67 for B-Sia1. In addition, this study demonstrates the therapeutic efficacy of phthalocyanines synthesized as sensitizers on the PC3 prostate cancer cell line through in vitro experiments. The application of these treatment modalities exhibited notable outcomes, leading to a substantial decrease in cell viability within the PC3 prostate cancer cell line. These findings highlight the potential of utilizing these synthesized phthalocyanines as promising therapeutic agents for prostate cancer treatment.

Design consideration of phthalocyanines as sensitizers for enhanced sono-photodynamic combinatorial therapy of cancer

Cancer remains one of the diseases with the highest incidence and mortality globally. Conventional treatment modalities have demonstrated threatening drawbacks including invasiveness, non-controllability, and development of resistance for some, including chemotherapy, radiation, and surgery. Sono-photodynamic combinatorial therapy (SPDT) has been developed as an alternative treatment modality which offers a non-invasive and controllable therapeutic approach. SPDT combines the mechanism of action of sonodynamic therapy (SDT), which uses ultrasound, and photodynamic therapy (PDT), which uses light, to activate a sensitizer and initiate cancer eradication. The use of phthalocyanines (Pcs) as sensitizers for SPDT is gaining interest owing to their ability to induce intracellular oxidative stress and initiate toxicity under SDT and PDT. This review discusses some of the structural prerequisites of Pcs which may influence their overall SPDT activities in cancer therapy.

Harnessing the power of goat milk-derived extracellular vesicles for medical breakthroughs: A review

Research into goat milk-derived extracellular vesicles (GMVs) has grown in popularity in recent years owing to their potential uses in several sectors, including medicine. GMVs are tiny, lipid-bound structures that cells secrete and use to transport bioactive substances like proteins, lipids, and nucleic acids. They may be extracted from different body fluids, including blood, urine, and milk, and have been found to play crucial roles in cell-to-cell communication. GMVs are a promising field of study with applications in preventing and treating various disorders. Their immune-modulating properties, for instance, have been investigated, and they have shown promise in treating autoimmune illnesses and cancer. They may be loaded with therapeutic compounds and directed to particular cells or tissues, but they have also been studied for their potential use as drug-delivery vehicles. Goat milk extracellular vesicles are an intriguing study topic with many possible benefits. Although more study is required to thoroughly understand their functioning and prospective applications, they provide a promising path for creating novel medical treatments and technology.

Detection of Arsenic(V) by Fluorescence Sensing Based on Chlorin e6-Copper Ion

The high toxicity of arsenic (As) can cause irreversible harm to the environment and human health. In this study, the chlorin e6 (Ce6), which emits fluorescence in the infrared region, was introduced as the luminescence center, and the addition of copper ion (Cu2+) and As(V) provoked a regular change in fluorescence at 652 nm, whereas that of As(III) was 665 nm, which was used to optionally detect Cu2+, arsenic (As(III), and As(V)). The limit of detection (LOD) values were 0.212 μM, 0.089 ppm, and 1.375 ppb for Cu2+, As(III), and As(V), respectively. The developed method can be used to determine Cu2+ and arsenic in water and soil with good sensitivity and selectivity. The 1:1 stoichiometry of Ce6 with Cu2+ was obtained from the Job plot that was developed from UV-visible spectra. The binding constants for Cu2+ and As(V) were established to be 1.248 × 105 M-1 and 2.35 × 1012 M-2, respectively, using B-H (Benesi-Hildebrand) plots. Fluorescence lifetimes, B-H plots, FT-IR, and 1H-NMR were used to postulate the mechanism of Cu2+ fluorescence quenching and As(V) fluorescence restoration and the interactions of the two ions with the Ce6 molecule.

Tumor fluorescence and oxygenation monitoring during photodynamic therapy with chlorin e6 photosensitizer

BACKGROUND

The study is aimed at developing a method for monitoring photodynamic therapy (PDT) of a tumor using chlorin-type photosensitizers (PSs). Lack of monitoring of chlorin e6 (Cе6) photobleaching, hemoglobin oxygenation and blood flow during light exposure can limit the PDT effectiveness.

MATERIALS AND METHODS

Phototheranostics includes spectral-fluorescence diagnostics of Ce6 distribution in the NIR range and PDT with simultaneous assessment of hemoglobin oxygenation and tumor blood flow. Fluorescence diagnostics and PDT were performed using the single laser λexc=660 ± 5 nm.

RESULTS

Combined spectroscopic PDT monitoring method allowed simultaneous estimation of Ce6 photobleaching, hemoglobin oxygenation and tumor vascular thrombosis during PDT without interrupting the therapeutic light exposure.

CONCLUSION

The developed method of tumor phototheranostics using chlorin-type PSs may make it possible to personalize the duration of therapeutic light exposure during PDT.

Macrophage-targeted ultrasound nanobubbles for highly efficient sonodynamic therapy of atherosclerotic plaques by modulating M1-to-M2 polarization

BACKGROUND AND AIMS

Sonodynamic therapy (SDT) is a new approach for the treatment of atherosclerosis (AS), yet the poor targeting ability of sonosensitizers limits its therapeutic efficacy. Herein, we reported a plaque-targeted nanoplatform modified with macrophage type A scavenger receptor (SR-A)-targeted peptide (designated as SR-A-Ce6NB) to augment the efficacy of low-intensity pulsed ultrasound (LIPUS)-mediated SDT of atherosclerotic plaque.

METHODS

SR-A-Ce6NB was fabricated by thin hydration method and biotin-avidin system, and its physicochemical properties, biocompatibility and plaque-targeting ability were investigated. RAW 264.7 cells were used for in vitro experimental studies. Male 6-week-old apolipoprotein E-deficient mice were fed a high-fat diet for 16 weeks to induce aortic atherosclerotic plaques. Plaque-bearing mice were randomly allocated into five groups (n = 6): control group, Ce6 + LIPUS group, Ce6NB + LIPUS group, SR-A-Ce6NB + LIPUS group and atorvastatin group. After treatment in each group, the aortic artery was harvested for Oil red O, H&E, Masson's trichrome staining, immunohistochemical and immunofluorescent staining.

RESULTS

SR-A-Ce6NB with high stability and excellent biocompatibility was successfully fabricated. SR-A-Ce6NB could actively target activated macrophages and selectively accumulate in the plaque. SR-A-Ce6NB could be triggered by LIPUS and had a more potent sonodynamic effect than free Ce6 to potentiate SDT. SR-A-Ce6NB-mediated SDT enhanced the anti-atherogenic effect via modulating M1-to-M2 macrophage polarization and had an earlier onset of action on plaque than the statin-mediated effect. No apparent side effect was observed after intravenous SR-A-Ce6NB injection and LIPUS exposure.

CONCLUSIONS

Macrophage-targeted nanoplatform SR-A-Ce6NB-mediated SDT provides a safe, effective and preferable anti-atherogenic therapy by mediating M1-to-M2 macrophage polarization.

Photoacid Generators for Biomedical Applications

Photoacid generators (PAGs) are compounds capable of producing hydrogen protons (H+ ) upon irradiation, including irreversible and reversible PAGs, which have been widely studied in photoinduced polymerization and degradation for a long time. In recent years, the applications of PAGs in the biomedical field have attracted more attention due to their promising clinical value. So, an increasing number of novel PAGs have been reported. In this review, the recent progresses of PAGs for biomedical applications is systematically summarized, including tumor treatment, antibacterial treatment, regulation of protein folding and unfolding, control of drug release and so on. Furthermore, a concept of water-dependent reversible photoacid (W-RPA) and its antitumor effect are highlighted. Eventually, the challenges of PAGs for clinical applications are discussed.

Mitochondrial Disruption Nanosystem Simultaneously Depressed Programmed Death Ligand-1 and Transforming Growth Factor-β to Overcome Photodynamic Immunotherapy Resistance

Currently, limited photosensitizers possess the capacity to reverse tumor hypoxia and reduce programmed death ligand-1 (PD-L1) and transforming growth factor-β (TGF-β) expression simultaneously, hindering the perfect photodynamic therapy (PDT) effect due to acquired immune resistance and the tumor hypoxic microenvironment. To tackle these challenges, in this research, we demonstrated that mitochondrial energy metabolism depression can be utilized as an innovative and efficient approach for reducing the expression of PD-L1 and TGF-β simultaneously, which may offer a design strategy for a more ideal PDT nanosystem. Through proteomic analysis of 5637 cells, we revealed that tamoxifen (TMX) can incredibly regulate PD-L1 expression in tumor cells. Then, to selectively deliver clinically used mitochondrial energy metabolism depressant TMX to solid tumors as well as design an ideal PDT nanosystem, we synthesized MHI-TMX@ALB by combining a mitochondria-targeted heptamethine cyanine PDT-dye MHI with TMX through self-assembly with albumin (ALB). Interestingly enough, the MHI-TMX@ALB nanoparticle demonstrated effective reversion of tumor hypoxia and inhibition of PD-L1 protein expression at a lower dosage (7.5 times to TMX), which then enhanced the efficacy of photodynamic immunotherapy via enhancing T-cell infiltration. Apart from this, by leveraging the heptamethine dye's targeting capacity toward tumors and TMX's role in suppressing TGF-β, MHI-TMX@ALB also more effectively mitigated 4T1 tumor lung metastasis development. All in all, the MHI-TMX@ALB nanoparticle could be used as a multifunctional economical PD-L1 and TGF-β codepression immune-regulating strategy, broadening the potential clinical applications for a more ideal PDT nanosystem.

Targeted treatment of atherosclerosis with protein-polysaccharide nanoemulsion co-loaded with photosensitiser and upconversion nanoparticles

Macrophages are the most abundant cell group in atherosclerosis (AS) lesions and play a vital role in all stages of AS progression. Recent research has shown that reactive oxygen species (ROS) generation from photodynamic therapy (PDT) induces macrophage autophagy to improve abnormal lipid metabolism and inflammatory environment. Especially in macrophage-derived foam cells, which has become a potential strategy for the treatment of AS. In this study, we prepared the conjugate (DB) of dextran (DEX) and bovine serum albumin (BSA). The DB was used as the emulsifier to prepare nanoemulsion loaded with upconversion nanoparticles (UCNPs) and chlorin e6 (Ce6) (UCNPs-Ce6@DB). The DEX modified on the surface of the nanoemulsion can recognise and bind to the scavenger receptor class A (SR-A) highly expressed on macrophages and promote the uptake of macrophage-derived foam cells in AS plates through SR-A-mediated endocytosis. In addition, UCNPs-Ce6@DB-mediated PDT enhanced ROS generation and induced autophagy in macrophage-derived foam cells, enhanced the expression of ABCA1, a protein closely related to cholesterol efflux, and inhibited the secretion of pro-inflammatory cytokines. Ultimately, UCNPs-Ce6@DB was shown to inhibit plaque formation in mouse models of AS. In conclusion, UCNPs-Ce6@DB offers a promising treatment for AS.

Putting a "C60 Ball" and Chain to Chlorin e6 Improves Its Cellular Uptake and Photodynamic Performances

Chlorin e6 (Ce6) and fullerene (C60) are among the most used photosensitizers (PSs) for photodynamic therapy (PDT). Through the combination of the chemical and photophysical properties of Ce6 and C60, in principle, we can obtain an "ideal" photosensitizer that is able to bypass the limitations of the two molecules alone, i.e., the low cellular uptake of Ce6 and the scarce solubility and absorption in the red region of the C60. Here, we synthesized and characterized a Ce6-C60 dyad. The UV-Vis spectrum of the dyad showed the typical absorption bands of both fullerene and Ce6, while a quenching of Ce6 fluorescence was observed. This behavior is typical in the formation of a fullerene-antenna system and is due to the intramolecular energy, or electron transfer from the antenna (Ce6) to the fullerene. Consequently, the Ce6-C60 dyad showed an enhancement in the generation of reactive oxygen species (ROS). Flow cytometry measurements demonstrated how the uptake of the Ce6 was strongly improved by the conjugation with C60. The Ce6-C60 dyad exhibited in A431 cancer cells low dark toxicity and a higher PDT efficacy than Ce6 alone, due to the enhancement of the uptake and the improvement of ROS generation.

Ultrasound Sonosensitizers for Tumor Sonodynamic Therapy and Imaging: A New Direction with Clinical Translation

With the rapid development of sonodynamic therapy (SDT), sonosensitizers have evolved from traditional treatments to comprehensive diagnostics and therapies. Sonosensitizers play a crucial role in the integration of ultrasound imaging (USI), X-ray computed tomography (CT), and magnetic resonance imaging (MRI) diagnostics while also playing a therapeutic role. This review was based on recent articles on multifunctional sonosensitizers that were used in SDT for the treatment of cancer and have the potential for clinical USI, CT, and MRI applications. Next, some of the shortcomings of the clinical examination and the results of sonosensitizers in animal imaging were described. Finally, this paper attempted to inform the future development of sonosensitizers in the field of integrative diagnostics and therapeutics and to point out current problems and prospects for their application.

Dissecting the Interactions between Chlorin e6 and Human Serum Albumin

Chlorin e6 (Ce6) is among the most used sensitizers in photodynamic (PDT) and sonodynamic (SDT) therapy; its low solubility in water, however, hampers its clinical exploitation. Ce6 has a strong tendency to aggregate in physiological environments, reducing its performance as a photo/sono-sensitizer, as well as yielding poor pharmacokinetic and pharmacodynamic properties. The interaction of Ce6 with human serum albumin (HSA) (i) governs its biodistribution and (ii) can be used to improve its water solubility by encapsulation. Here, using ensemble docking and microsecond molecular dynamics simulations, we identified the two Ce6 binding pockets in HSA, i.e., the Sudlow I site and the heme binding pocket, providing an atomistic description of the binding. Comparing the photophysical and photosensitizing properties of Ce6@HSA with respect to the same properties regarding the free Ce6, it was observed that (i) a red-shift occurred in both the absorption and emission spectra, (ii) a maintaining of the fluorescence quantum yield and an increase of the excited state lifetime was detected, and (iii) a switch from the type II to the type I mechanism in a reactive oxygen species (ROS) production, upon irradiation, took place.