Crosstalk between oxidative stress-induced apoptotic and autophagic signaling pathways in Zn(II) phthalocyanine photodynamic therapy of melanoma

Rod-Shaped Au@Ce Nano-Platforms for Enhancing Photodynamic Tumor Collaborative Therapy

Tumor photodynamic therapy (PDT) relies on intratumoral free radicals, while the limited oxygen source and the depletion of tissue oxygen may exacerbate the hypoxia. As the treatment progresses, there will eventually be a problem of insufficient free radicals. Here, it is found that Au@CeO2 nano-rods (Au@Ce NRs), assembled by gold nano-rods (Au NRs) and ceria nanoparticles (CeO2 NPs), can efficaciously absorb near-infrared light (NIR) to promote the release of oxygen and free radicals. Au@Ce NRs exhibit a higher proportion of Ce3+ (Ce2O3) after oxygen release, while Ce3+ is subsequently oxidized to Ce4+ (CeO2) by trace H2O2. Interestingly, Au@Ce NRs re-oxidized by trace H2O2 can re-release oxygen and free radicals again upon NIR treatment, achieving oxygenation/oxygen evolution, similar to charging/discharging. This loop maximizes the conversion of limited oxygen source into highly cytotoxic free radicals. As a result, when B16-F10 cells are treated by NIR/Au@Ce NRs, more tumor cells undergo apoptosis, consistent with the higher level of free radicals. Importantly, NIR/Au@Ce NRs successfully suppresses tumor growth and promotes the generation of epidermal collagen fibers in the transplanted tumor model. Therefore, the rod-shaped Au@Ce NRs provide an ideal platform for maximizing the utilization of intratumoral oxygen sources and improving the treatment of melanoma.

pH-sensitive phthalocyanine-loaded polymeric nanoparticles as a novel treatment strategy for breast cancer

Novel pH-sensitive polymeric photosensitizer carriers from the phthalocyanine (Pc) group were investigated as potential photodynamic therapy drugs for the treatment of breast cancer. Their high antiproliferative activity was confirmed by photocytotoxicity studies, which indicated their high efficacy and specificity toward the SK-BR-3 cell line. Importantly, the Pcs encapsulated in the polymeric nanoparticle (NP) carrier exhibited a much better penetration into the acidic environment of tumor cells than their free form. The investigated Pc4-NPs and TT1-NPs exhibited a high selectivity to healthy fibroblasts as well as non-toxicity without irradiation. This paper describes the detailed mechanism of action of the evaluated compounds by measuring reactive oxygen species (ROS), including singlet oxygen; imaging cellular localization; and analyzing key signaling pathway proteins. An additional advantage of the evaluated compounds is their ability to inhibit the Akt protein expression, including its phosphorylation, which the Western blot test confirmed. This is particularly important because breast cancers often overexpress the HER-2 receptor-related signaling proteins. Moreover, an analysis of proteins such as GLUT-1, HO-1, phospho-p42/44, and BID revealed the significant involvement of ROS in disrupting cellular homeostasis, thereby leading to the induction of oxidative stress and resulting in apoptotic cell death.

Photodynamic Therapy in Cancer: Insights into Cellular and Molecular Pathways

Photodynamic therapy is a non-ionizing radiation treatment that utilizes a photosensitizer in combination with light to produce singlet oxygen. This singlet oxygen induces anti-cancer effects by causing apoptotic, necrotic, or autophagic cell death in tumor cells. Currently, photodynamic therapy is employed in oncology to treat various cancers. In the presence of oxygen, this non-invasive approach leads to direct tumor cell death, damage to microvasculature, and the induction of a local inflammatory response. These effects allow photodynamic therapy to be effective in treating early-stage tumors, extending survival in cases where surgery is not feasible, and significantly improving quality of life. In this paper, we provide a state of the art on cytomolecular mechanisms and associated pathways involved in photodynamic therapy. By integrating these mechanistic insights with the most recent advancements in nanotechnology, this phototherapeutic approach has the potential to become a prevalent treatment option within conventional cancer therapies, enhancing its application in precision medicine.

Anti-angiogenic effects of cationic zinc (II) phthalocyanine derivatives through photodynamic therapy

In this study, the in vitro photodynamic therapy (PDT) activity of two zinc phthalocyanines (ZnPc1 and ZnPc2) was systematically examined in human umbilical vein endothelial cells, focusing on PDT-induced cytotoxicity, reactive oxygen species (ROS) generation, and inhibition of angiogenic processes. Both the ZnPcs demonstrated minimal cytotoxicity in the absence of light, confirming their safety as photosensitizers. ZnPc-PDT led to significant cell death via apoptosis. ZnPc1 exhibited enhanced ROS generation, particularly at elevated concentrations. Furthermore, ZnPc1-mediated PDT showed more pronounced inhibition of endothelial cell migration, invasion, and capillary-like tube formation than ZnPc2. Wound-healing assays revealed a substantial delay in human umbilical vein endothelial cell (HUVEC) migration following ZnPc1-PDT, which also displayed a more significant inhibition of VEGF-induced directional migration and invasion. Endothelial tube formation was more effectively disrupted by ZnPc1-PDT, even at lower concentrations, compared to ZnPc2. Collectively, these findings highlight the superior cytotoxic and anti-angiogenic properties of ZnPc1 compared with ZnPc2, highlighting its potential as a highly effective photosensitizer for photodynamic therapy. The ability of ZnPc1 to simultaneously target tumor cells and disrupt angiogenesis establishes it as a potent candidate for integrated cancer therapies that combine both antitumor and antiangiogenic strategies, offering a more effective approach to combat cancer progression.

Advancements in nanotechnology-driven photodynamic and photothermal therapies: mechanistic insights and synergistic approaches for cancer treatment

Cancer is a disease that involves uncontrolled cell division triggered by genetic damage to the genes that control cell growth and division. Cancer starts as a localized illness, but subsequently spreads to other areas in the human body (metastasis), making it incurable. Cancer is the second most prevalent cause of mortality worldwide. Every year, almost ten million individuals get diagnosed with cancer. Although different cancer treatment options exist, such as chemotherapy, radiation, surgery and immunotherapy, their clinical efficacy is limited due to their significant side effects. New cancer treatment options, such as phototherapy, which employs light for the treatment of cancer, have sparked a growing fascination in the cancer research community. Phototherapies are classified into two types: photodynamic treatment (PDT) and photothermal therapy (PTT). PDT necessitates the use of a photosensitizing chemical and exposure to light at a certain wavelength. Photodynamic treatment (PDT) is primarily based on the creation of singlet oxygen by the stimulation of a photosensitizer, which is then used to kill tumor cells. PDT can be used to treat a variety of malignancies. On the other hand, PTT employs a photothermal molecule that activates and destroys cancer cells at the longer wavelengths of light, making it less energetic and hence less hazardous to other cells and tissues. While PTT is a better alternative to standard cancer therapy, in some irradiation circumstances, it can cause cellular necrosis, which results in pro-inflammatory reactions that can be harmful to therapeutic effectiveness. Latest research has revealed that PTT may be adjusted to produce apoptosis instead of necrosis, which is attractive since apoptosis reduces the inflammatory response.

Dihydroartemisinin enhances the anti-tumour effect of photodynamic therapy by targeting PKM2-mediated glycolysis in oesophageal cancer cell

Photodynamic therapy (PDT) has been demonstrated to provide immediate relief of oesophageal cancer patients' re-obstruction and extend their lifespan. However, tumour regrowth may occur after PDT due to enhanced aerobic glycolysis. Previous research has confirmed the inhibitory effect of Dihydroartemisinin (DHA) on aerobic glycolysis. Therefore, the current study intends to investigate the function and molecular mechanism of DHA targeting tumour cell aerobic glycolysis in synergia PDT. The combined treatment significantly suppressed glycolysis in vitro and in vivo compared to either monotherapy. Exploration of the mechanism through corresponding experiments revealed that pyruvate kinase M2 (PKM2) was downregulated in treated cells, whereas overexpression of PKM2 nullified the inhibitory effects of DHA and PDT. This study proposes a novel therapeutic strategy for oesophageal cancer through DHA-synergized PDT treatment, targeting inhibit PKM2 to reduce tumour cell proliferation and metastasis.

Targeting of M2 macrophages with IL-13-functionalized liposomal prednisolone inhibits melanoma angiogenesis in vivo

The intricate cooperation between cancer cells and nontumor stromal cells within melanoma microenvironment (MME) enables tumor progression and metastasis. We previously demonstrated that the interplay between tumor-associated macrophages (TAMs) and melanoma cells can be disrupted by using long-circulating liposomes (LCLs) encapsulating prednisolone phosphate (PLP) (LCL-PLP) that inhibited tumor angiogenesis coordinated by TAMs. In this study, our goal was to improve LCL specificity for protumor macrophages (M2-like (i.e., TAMs) macrophages) and to induce a more precise accumulation at tumor site by loading PLP into IL-13-conjugated liposomes (IL-13-LCL-PLP), since IL-13 receptor is overexpressed in this type of macrophages. The IL-13-LCL-PLP liposomal formulation was obtained by covalent attachment of thiolated IL-13 to maleimide-functionalized LCL-PLP. C57BL/6 mice bearing B16.F10 s.c melanoma tumors were used to investigate the antitumor action of LCL-PLP and IL-13-LCL-PLP. Our results showed that IL-13-LCL-PLP formulation remained stable in biological fluids after 24h and it was preferentially taken up by M2 polarized macrophages. IL-13-LCL-PLP induced strong tumor growth inhibition compared to nonfunctionalized LCL-PLP at the same dose, by altering TAMs-mediated angiogenesis and oxidative stress, limiting resistance to apoptosis and invasive features in MME. These findings suggest IL-13-LCL-PLP might become a promising delivery platform for chemotherapeutic agents in melanoma.

Gallium octacarboxyphthalocyanine hydroxide as a potential pro-apoptotic drug against cancer skin cells

Novel anticancer strategies reduce side effects on healthy tissues by elevating the lethal abilities of cancer cells. The development of effective particles with good bioavailability and selectivity remains problematic. For undesirable features, green chemistry is used to synthesize the best compounds, or natural-based particles are improved. Photodynamic therapy (PDT), modelled on phthalocyanines (Pcs), still delivers second-generation sensitizers which are complemented with metal ions, such as Zn2+, Al3+, or Ga3+. Gallium octacarboxyphthalocyanine hydroxide (Ga(OH)PcOC), was designed for skin cancer treatment, and was used as a pro-apoptotic and pro-oxidative agent on normal skin cell lines, fibroblasts (NHDF), and keratinocytes (HaCaT), with promising selectivity against melanoma cancer cells (Me45) in vitro. Compared to the previous reported findings, where the ZnPcOC acted on the skin cell lines at higher doses, the sensitivities to the Ga(OH)PcOC allows for an effective reduction of the sensitizer dose. The effective dose, for a novel Ga(OH)PcOC particle, was significantly reduced from 30 µM to 6 µM on Me45 cancer cells, tested using 24 h MTT viability, as well as cytometric pro-oxidative and pro-apoptotic assays. The promising photosensitizer did not reduce viability in normal fibroblasts and keratinocytes without reactive oxygen species (ROS) elevation or apoptosis induction. The improvement to the previous findings is better Ga-based photosensitizer selectivity against the cancer Me45 cells, then observed in Zn-based compounds.

A Lysosome-Targeting hNEU1 Inhibitor Treats Myocardial Infarction: A Potential Therapeutic Breakthrough

The overexpression of NEU1 has recently been certified as being associated with myocardial infarction. However, the pursuit of an efficacious human NEU1 (hNEU1) inhibitor remains challenging, and viral NEU1 (viNEU1) inhibitor drugs are significantly weaker in terms of hNEU1 inhibition. Recognizing that hNEU1 is located within the lysosome, we designed a series of lysosome-targeting compounds, derived from oseltamivir, aimed at hNEU1 inhibition. Among these compounds, OsMo exhibits the most potent activity. Our findings reveal that OsMo accumulates within lysosomes and releases its pharmacophore via enzymatic catalysis. OsMo enhances hNEU1 inhibition by accumulating pharmacophores at the target site. OsMo exhibits improved regulation of abnormal autophagy during myocardial injury, demonstrating superior efficacy in treating myocardial infarction in vivo. Furthermore, OsMo exhibits acceptable pharmacokinetic parameters. Importantly, the development of molecules with lysosome-targeting abilities represents a promising avenue for addressing myocardial injuries linked to hNEU1 overexpression.

Recent Progress in Photothermal, Photodynamic and Sonodynamic Cancer Therapy: Through the cGAS-STING Pathway to Efficacy-Enhancing Strategies

Photothermal, photodynamic and sonodynamic cancer therapies offer opportunities for precise tumor ablation and reduce side effects. The cyclic guanylate adenylate synthase-stimulator of interferon genes (cGAS-STING) pathway has been considered a potential target to stimulate the immune system in patients and achieve a sustained immune response. Combining photothermal, photodynamic and sonodynamic therapies with cGAS-STING agonists represents a newly developed cancer treatment demonstrating noticeable innovation in its impact on the immune system. Recent reviews have concentrated on diverse materials and their function in cancer therapy. In this review, we focus on the molecular mechanism of photothermal, photodynamic and sonodynamic cancer therapies and the connected role of cGAS-STING agonists in treating cancer.

Nutrition and melanoma: the contribution of trace elements in onset, progression, and treatment of melanoma

Melanoma is a highly malignant and drug-resistant disease that imposes a substantial economic burden on the world. There are many studies linking trace elements to diverse types of cancers, including melanoma. This review elucidates the relationship between trace elements exposure and melanoma. It was identified that copper, manganese, selenium, zinc, iron, and many other trace elements were associated with melanoma in humans. In terms of epidemiology, different elements have different correlations with melanoma. These trace elements affect the occurrence and development of melanoma through various mechanisms, such as oxidative stress and the MAPK pathway. The literature on the role of trace elements in the pathogenesis and treatment of melanoma depicts promising prospects for this field.

The phototoxic effect of a gold-antibody-based nanocarrier of phthalocyanine on melanoma monolayers and tumour spheroids

In recent years, photodynamic therapy (PDT) has garnered significant attention in cancer treatment due to its increased potency and non-invasiveness compared to conventional therapies. Active-targeted delivery of photosensitizers (PSs) is a mainstay strategy to significantly reduce its off-target toxicity and enhance its phototoxic efficacy. The anti-melanoma inhibitory activity (MIA) antibody is a targeting biomolecule that can be integrated into a nanocarrier system to actively target melanoma cells due to its specific binding to MIA antigens that are highly expressed on the surface of melanoma cells. Gold nanoparticles (AuNPs) are excellent nanocarriers due to their ability to encapsulate a variety of therapeutics, such as PSs, and their ability to bind with targeting moieties for improved bioavailability in cancer cells. Hence, we designed a nanobioconjugate (NBC) composed of zinc phthalocyanine tetrasulfonic acid (ZnPcS4), AuNPs and anti-MIA Ab to improve ZnPcS4 bioavailability and phototoxicity in two and three-dimensional tumour models. In summary, we demonstrated that this nanobioconjugate showed significant inhibitory effects on both melanoma models due to increased ROS yields and bioavailability of the melanoma cells compared to free ZnPcS4.

Aluminium phthalocyanine-mediated photodynamic therapy induces ATM-related DNA damage response and apoptosis in human oesophageal cancer cells

Introduction

Photodynamic therapy (PDT) is a light-based technique used in the treatment of malignant and non-malignant tissue. Aluminium-phthalocyanine chloride tetra sulfonate (AlPcS4Cl)-mediated PDT has been well investigated on several cancer types, including oesophageal cancer. However, the effects of (AlPcS4Cl)-mediated PDT on DNA damage response and the mechanism of cell death in oesophageal cancer needs further investigation.

Methods

Here, we examined the in vitro effects of AlPcS4Cl-mediated PDT on cell cycle, DNA damage response, oxidative stress, and intrinsic apoptotic cell death pathway in HKESC-1 oesophageal cancer cells. The HKESC-1 cells were exposed to PDT using a semiconductor laser diode (673.2 nm, 5 J/cm2 fluency). Cell viability and cytotoxicity were determined by the ATP cell viability assay and the lactate dehydrogenase (LDH) release assay, respectively. Cell cycle and DNA damage response (DDR) analyses were conducted using the Muse™ cell cycle kit and the Muse® multi-color DNA damage kit, respectively. The mode of cell death was identified using the Annexin V-FITC/PI detection assay and Muse® Autophagy LC3 antibody-based kit. The intrinsic apoptotic pathway was investigated by measuring the cellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm) function, cytochrome c levels and the activity of caspase 3/7 enzymes.

Results

The results show that AlPcS4Cl-based PDT reduced cell viability, induced cytotoxicity, cell cycle arrest at the G0/G1 phase, and DNA double-strand break (DSB) through the upregulation of the ataxia telangiectasia mutated (ATM), a DNA damage sensor. In addition, the findings showed that AlPcS4Cl-based PDT induced cell death via apoptosis, which is observed through increased ROS production, reduced ΔΨm, increased cytochrome c release, and activation of caspase 3/7 enzyme. Finally, no autophagy was observed in the AlPcS4Cl-mediated PDT-treated cells.

Conclusion

Our findings showed that apoptotic cell death is the main cell death mechanism triggered by AlPcS4Cl-mediated PDT in oesophageal cancer cells.

The Role of Intracellular and Extracellular Vesicles in the Development of Therapy Resistance in Cancer

Cancer is the second leading cause of global mortality and claims approximately 10 million lives annually. Despite advances in treatments such as surgery, chemotherapy, and immunotherapy, resistance to these methods has emerged. Multidrug resistance (MDR), where cancer cells resist diverse treatments, undermines therapy effectiveness, escalating mortality rates. MDR mechanisms include, among others, drug inactivation, reduced drug uptake, enhanced DNA repair, and activation of survival pathways such as autophagy. Moreover, MDR mechanisms can confer resistance to other therapies like radiotherapy. Understanding these mechanisms is crucial for improving treatment efficacy and identifying new therapeutic targets. Extracellular vesicles (EVs) have gathered attention for their role in cancer progression, including MDR development through protein transfer and genetic reprogramming. Autophagy, a process balancing cellular resources, also influences MDR. The intersection of EVs and autophagy further complicates the understanding of MDR. Both extracellular (exosomes, microvesicles) and intracellular (autophagic) vesicles contribute to therapy resistance by regulating the tumor microenvironment, facilitating cell communication, and modulating drug processing. While much is known about these pathways, there is still a need to explore their potential for predicting treatment responses and understanding tumor heterogeneity.

Nano-phototherapy: Favorable prospects for cancer treatment

Nanotechnology-based phototherapies have drawn interest in the fight against cancer because of its noninvasiveness, high flexibility, and precision in terms of cancer targeting and drug delivery based on its surface properties and size. Phototherapy has made remarkable development in recent decades. Approaches to phototherapy, which utilize nanomaterials or nanotechnology have emerged to contribute to advances around nanotechnologies in medicine, particularly for cancers. A brief overviews of the development of photodynamic therapy as well as its mechanism in cancer treatment is provided. We emphasize the design of novel nanoparticles utilized in photodynamic therapy while summarizing the representative progress during the recent years. Finally, to forecast important future research in this area, we examine the viability and promise of photodynamic therapy systems based on nanoparticles in clinical anticancer treatment applications and briefly make mention of the elimination of all reactive metabolites pertaining to nano formulations inside living organisms providing insight into clinical mechanistic processes. Future developments and therapeutic prospects for photodynamic treatments are anticipated. Our viewpoints might encourage scientists to create more potent phototherapy-based cancer therapeutic modalities. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

The Efficacy of Zinc Phthalocyanine Nanoconjugate on Melanoma Cells Grown as Three-Dimensional Multicellular Tumour Spheroids

Melanoma remains a major public health concern that is highly resistant to standard therapeutic approaches. Photodynamic therapy (PDT) is an underutilised cancer therapy with an increased potency and negligible side effects, and it is non-invasive compared to traditional treatment modalities. Three-dimensional multicellular tumour spheroids (MCTS) closely resemble in vivo avascular tumour features, allowing for the more efficient and precise screening of novel anticancer agents with various treatment combinations. In this study, we utilised A375 human melanoma spheroids to screen the phototoxic effect of zinc phthalocyanine tetrasulfonate (ZnPcS4) conjugated to gold nanoparticles (AuNP). The nanoconjugate was synthesised and characterised using ultraviolet-visible spectroscopy, a high-resolution transmission electron microscope (TEM), dynamic light scattering (DLS), and zeta potential (ZP). The phototoxicity of the nanoconjugate was tested on the A375 MCTS using PDT at a fluency of 10 J/cm2. After 24 h, the cellular responses were evaluated via microscopy, an MTT viability assay, an ATP luminescence assay, and cell death induction using annexin propidium iodide. The MTT viability assay demonstrated that the photoactivated ZnPcS4, at a concentration of 12.73 µM, caused an approximately 50% reduction in the cell viability of the spheroids. When conjugated to AuNPs, the latter significantly increased the cellular uptake and cytotoxicity in the melanoma spheroids via the induction of apoptosis. This novel Zinc Phthalocyanine Nanoconjugate shows promise as a more effective PDT treatment modality.

Mechanistic investigation of the differential synergistic neurotoxicity between pesticide metam sodium and copper or zinc

Epidemiological studies suggest neurological disorders have been associated with the co-exposure to certain pesticides and transition metals. The present study aims to investigate whether co-exposure to the widely-used pesticide metam sodium and copper (Cu²⁺) or zinc ion (Zn²⁺) is able to cause synergistic neurotoxicity in neural PC12 cells and its possible mechanism(s). We found that both metam/Cu²⁺ and metam/Zn²⁺ synergistically induced apoptosis, intracellular Cu²⁺/Zn²⁺ uptake, reactive oxygen species (ROS) accumulation, double-strand DNA breakage, mitochondrial membrane potential decrease, and nerve function disorder. In addition, metam/Cu²⁺ was shown to release cytochrome c and apoptosis-inducing factor (AIF) from mitochondria to cytoplasm and nucleus, respectively, and activate the caspase 9, 8, 3, 7. However, metam/Zn²⁺ induced caspase 7 activation and AIF translocation and mildly activated cytochrome c/caspase 9/caspase 3 pathway. Furthermore, metam/Cu²⁺ activated caspase 3/7 by the p38 pathway, whereas metam/Zn²⁺ did so via both the p38 and JNK pathways. These results demonstrated that metam/Cu²⁺ or metam/Zn²⁺ co-exposure cause synergistic neurotoxicity via different mechanisms, indicating a potential risk to human health when they environmentally co-exist.

Photodynamic therapy reduces cell viability, migration and triggers necroptosis in prostate tumor cells

Prostate cancer is the most common cancer in American men, aside from skin cancer. As an alternative cancer treatment, photodynamic laser therapy (PDT) can be used to induce cell death. We evaluated the PDT effect, using methylene blue as a photosensitizer, in human prostate tumor cells (PC3). PC3 were subjected to four different conditions: DMEM (control); laser treatment (L-660 nm, 100 mW, 100 J.cm^-2); methylene blue treatment (MB-25 μM, 30 min), and MB treatment followed by low-level red laser irradiation (MB-PDT). Groups were evaluated after 24 h. MB-PDT treatment reduced cell viability and migration. However, because MB-PDT did not significantly increase the levels of active caspase-3 and BCL-2, apoptosis was not the primary mode of cell death. MB-PDT, on the other hand, increased the acid compartment by 100% and the LC3 immunofluorescence (an autophagy marker) by 254%. Active MLKL level, a necroptosis marker, was higher in PC3 cells after MB-PDT treatment. Furthermore, MB-PDT resulted in oxidative stress due to a decrease in total antioxidant potential, catalase levels, and increased lipid peroxidation. According to these findings, MB-PDT therapy is effective at inducing oxidative stress and reducing PC3 cell viability. In such therapy, necroptosis is also an important mechanism of cell death triggered by autophagy.

Self-assembled nanoparticles based on cationic mono-/AIE tetra-nuclear Ir(III) complexes: long wavelength absorption/near-infrared emission photosensitizers for photodynamic therapy

Cyclometalated Ir(III) complexes as photosensitizers (PSs) have attracted widespread attention because of their good photostability and efficient ¹O₂ production ability. However, their strong absorption in the UV-vis region severely limits their applications in photodynamic therapy (PDT) because the short wavelength illuminating light can be easily absorbed by the skin and subcutaneous adipose tissue causing damage to the patient's normal tissue. Herein, mono- and tetra-nuclear Ir(III) complex-porphyrin conjugates are rationally designed and synthesized, especially [TPP-4Ir]4+ exhibits obvious aggregation-induced emission (AIE) characteristics. PSs comprising Ir(III) complex-porphyrin conjugates self-assembled as nanoparticles (NPs) are successfully achieved. The obtained [TPP-Ir]+ NPs and [TPP-4Ir]4+ NPs exhibit long wavelength absorption (500-700 nm) and near-infrared emission (635-750 nm), successfully overcoming the inherent defects of short wavelength absorption of traditional Ir(III) complexes. Moreover, [TPP-4Ir]4+ NPs exhibit good biocompatibility, high ¹O₂ generation ability, low half-maximal inhibitory concentration (IC₅₀) (0.47 × 10^-6 M), potent cytotoxicity toward cancer cells and superior cellular uptake under white light irradiation. This work extends the scope for transition metal complex PSs with promising clinical applications.

All-in-one device for mapping the interactive effects of photodynamic therapy dosimetry in tumor gaseous microenvironment

Photodynamic therapy (PDT) elicits cell death, vascular damage, or/and anti-tumor host immune response upon activating the administered photosensitive drug by an appropriate light source. Because PDT is heavily dependent on tissue oxygen (O₂) in essence, the concentration-dependent impact of O₂ on tailoring cellular response to PDT remains an in-depth investigation. As a multifaceted modality, optimal combinations of photosensitizer (PS) concentration, light dose, and O₂ delivery are critical to achieve ideal therapeutic outcomes. We herein present a fully integrated all-in-one device for the in vitro assessment of PDT efficacy synchronizing the quantitative control of three PDT disciplines simultaneously, aiming at 1) identifying the influence of varying gaseous microenvironments on PDT; and 2) determining the contribution of each PDT factor and estimating the strength of their synergic effect. The gas-gradient-generating unit for contactless headspace O₂ delivery and spatial light control filtering layer in our device could either work as a stand-alone module or combine to screen a range of experimental PDT parameters. By sweeping a total of 128 conditions over four 5-aminolevulinic acid (5-ALA) concentrations, four light dosages, and eight O₂ levels in one single experiment, we determined the main effects of the three key PDT agents and highlighted the interactive effect between 5-ALA and light after full-factorial statistical analysis. Our device is not only a versatile tool for predicting PDT efficacy during the translational study but also provides valuable multidimensional information for the interrelation between key PDT factors, which may expedite clinical PDT dosimetry and furnish new insights for the fundamental understanding of photobiological processes.

Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

Role of ROS‑mediated autophagy in melanoma (Review)

Melanoma is the most aggressive form of skin cancer with the poorest prognosis and its pathogenesis has yet to be fully elucidated. As key factors that regulate cellular homeostasis, both reactive oxygen species (ROS) and autophagy are involved in the development of melanoma, from melanomagenesis to progression and drug resistance. However, the interaction between ROS and autophagy in the etiology and treatment of melanoma is not well characterized. The present review examined the production of ROS and the role of oxidative stress in melanoma, and summarized the role of ROS‑mediated autophagy in melanomagenesis and melanoma cell fate decision following treatment with various anticancer drugs. The present findings may lead to a better understanding of the pathogenesis and progression of melanoma, and suggest promising treatment options for this disease.

Melanosomal targeting via caveolin-1 dependent endocytosis mediates ZN(II) phthalocyanine phototoxic action in melanoma cells

Melanosomes have been considered crucial targets in melanoma treatments. In this study we explored the role of melanosomes in photodynamic therapy (PDT), employing the synthetic Zn(II) phthalocyanine Pc13, a potent photosensitizer that promotes melanoma cell death after irradiation. Phototoxic action is mediated by reactive oxygen species increase. The internalization mechanism of Pc13 and its consequent subcellular localization were evaluated in melanotic B16-F0 cells. Pharmacological inhibitors of dynamin or caveolae, but not of clathrin, decreased Pc13 cellular uptake and phototoxicity. Similar results were obtained when cells over-expressed dominant negative mutants of dynamin-2 and caveolin-1, indicating that Pc13 is internalized by caveolae-mediated endocytosis. Confocal microscopy analysis revealed that Pc13 targets melanosomes and damage of these structures after irradiation was demonstrated by transmission electron microscopy. Treatment of pigmented B16-F0 and WM35 melanoma cells with the melanin synthesis inhibitor phenylthiourea for 48 h led to cell depigmentation and enhanced cell death after irradiation, whereas a 3-h period of inhibition did not modify melanin content but produced a marked reduction of Pc13 phototoxicity, together with a decrease of oxidative melanin synthesis intermediates. In contrast, the effect of Pc13 in amelanotic A375 cells was not altered by phenylthiourea treatment. These results provide evidence that melanosomes have a dual role in the efficacy of PDT. While melanin antagonizes the phototoxic action of Pc13, the release of cytotoxic synthetic intermediates to cytosol after irradiation and melanosome damage is conducive to the phototoxic response. Based on these findings, we demonstrate that melanosome-targeted PDT could be an effective approach for melanoma treatment.

Synergistic gentamicin-photodynamic therapy against resistant bacteria in burn wound infections

BACKGROUND

Multi-resistant bacteria, a result of the abuse of antibiotics, have greatly frustrated the effectiveness of antibiotics and produced a variety of side-effects. The combination of antibiotics with other therapies like antimicrobial photodynamic therapy (aPDT) may provide a useful strategy for fighting resistant bacteria. Here, the synergistic bactericidal effects of toluidine blue (TB)-aPDT and gentamicin (GEN) were evaluated in vitro and in vivo.

METHODS

The Post-antibacterial effects were measured at 600 nm (OD600) by a microplate reader. The bacterial envelope and biofilm were observed by a field emission scanning electron microscope. The expression of oxidative stress and Agr system-related genes was analyzed by qRT-PCR after GEN combined with TB-aPDT (GEN&aPDT). Besides, the burn infection model was established to investigate the cloning efficiency of immobilized bacteria, wound healing and inflammatory factors in the lesions.

RESULTS

GEN&aPDT could inhibit the growth of S. aureus and multidrug-resistant S. aureus (MDR S. aureus) for up to 15 h, and destroyed the cell envelope and biofilm structure of S. aureus and MDR S. aureus. During the process, ROS played an important role, inducing oxidative stress and downregulating the expression of AgrA, AgrB and PSM in the Agr system, resulting in decreased bacterial virulence and infectivity. In addition, GEN&aPDT cotreatment could effectively promoted wound healing in burn-infected mice by reducing the numbers of bacterial colonization in the wound, decreasing the content of inflammatory factors, and increasing the expression of growth factors.

CONCLUSION

The present study confirmed a bactericidal synergy between GEN and aPDT in vitro and in vivo, therein, the oxidative stress exhibited an important role in decreasing bacterial virulence and infectivity, which may bring new ideas for the treatment of bacterial resistance.

Targeting Microenvironment of Melanoma and Head and Neck Cancers in Photodynamic Therapy

Background:

Photodynamic therapy (PDT), in comparison to other skin cancers, is still far less effective for melanoma, due to the strong absorbance and the role of melanin in cytoprotection. The tumour microenvironment (TME) has a significant role in tumour progression, and the hypoxic TME is one of the main reasons for melanoma progression to metastasis and its resistance to PDT. Hypoxia is also a feature of solid tumours in the head and neck region that indicates negative prognosis.

Objective:

The aim of this study was to individuate and describe systematically the main strategies in targeting the TME, especially hypoxia, in PDT against melanoma and head and neck cancers (HNC), and assess the current success in their application.

Methods:

PubMed was used for searching, in MEDLINE and other databases, for the most recent publications on PDT against melanoma and HNC in combination with the TME targeting and hypoxia.

Results:

In PDT for melanoma and HNC, it is very important to control hypoxia levels, and amongst the different approaches, oxygen self-supply systems are often applied. Vascular targeting is promising, but to improve it, optimal drug-light interval, and formulation to increase the accumulation of the photosensitiser in the tumour vasculature, have to be established. On the other side, the use of angiogenesis inhibitors, such as those interfering with VEGF signalling, is somewhat less successful than expected and needs to be further investigated.

Conclusion:

The combination of PDT with immunotherapy by using multifunctional nanoparticles continues to develop and seems to be the most promising for achieving a complete and lasting antitumour effect.

The Surprisingly Positive Effect of Zinc-Phthalocyanines With High Photodynamic Therapy Efficacy of Melanoma Cancer

Phthalocyanine (Pc) dyes are photoactive molecules that can absorb and emit light in the visible spectrum, especially in the red region of the spectrum, with great potential for biological scopes. For this target, it is important to guarantee a high Pc solubility, and the use of suitable pyridinium units on their structure can be a good strategy to use effective photosensitizers (PSs) for photodynamic therapy (PDT) against cancer cells. Zn(II) phthalocyanines (ZnPcs) conjugated with thiopyridinium units (1–3) were evaluated as PS drugs against B16F10 melanoma cells, and their photophysical, photochemical, and in vitro photobiological properties were determined. The photodynamic efficiency of the tetra- and octa-cationic ZnPcs 1–3 was studied and compared at 1, 2, 5, 10, and 20 µM. The different number of charge units, and the presence/absence of a-F atoms on the Pc structure, contributes for their PDT efficacy. The 3-(4′,5′-dimethylthiazol-2′-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays on B16F10 melanoma cells show a moderate to high capacity to be photoinactivated by ZnPcs 1–3 (ZnPc 1 > ZnPc 2 > ZnPc 3). The best PDT conditions were found at a Pc concentration of 20 μM, under red light (λ = 660 ± 20 nm) at an irradiance of 4.5 mW/cm² for 667 s (light dose of 3 J/cm²). In these conditions, it is noteworthy that the cationic ZnPc 1 shows a promising photoinactivation ratio, reaching the detection limit of the MTT method. Moreover, these results are comparable to the better ones in the literature.

Induction of apoptosis and autosis in cardiomyocytes by the combination of homocysteine and copper via NOX-mediated p62 expression

High levels of homocysteine (Hcy) associated with cardiovascular events are accompanied by increased copper (Cu) concentrations in the blood. Hcy has been shown to promote endothelial dysfunction, whereas the effect of Hcy on cardiomyocytes and the role of Cu in the pathogenesis remain less understood. In the present study, it is demonstrated that the combination of Hcy and Cu²⁺-induced apoptosis and autosis of cardiomyocytes simultaneously, and thus led to cardiac dysfunction in hyperhomocysteinemic rats. These effects were associated with p22^phox activation and NADPH oxidase (NOX)-mediated p62 upregulation. Inhibition of the expression of p22^phox or p62 in cardiomyocytes significantly attenuated Hcy and Cu²⁺-mediated reactive oxygen species (ROS) generation and cell death. Furthermore, interrupting the NOX-p62 axis prevented diastolic dysfunction in hyperhomocysteinemic rats (HcyR). These findings establish that the induction of apoptosis and autosis of cardiomyocytes through stimulating the NOX-p62-signaling pathway constitutes a novel mechanism of Hcy and Cu-induced cardiac dysfunction.

Tetrandrine reduces oxidative stress, apoptosis, and extracellular matrix degradation and improves intervertebral disc degeneration by inducing autophagy

Tetrandrine (TET) was reported to be an autophagy agonist, and the activating autophagy could delay intervertebral disc degeneration (IDD). Our study focused on exploring whether TET attenuated tert butyl hydrogen peroxide (TBHP)-induced nucleus pulposus (NP) cell injury and delayed rat IDD by inducing autophagy. In vitro, cytotoxicity was detected by MTT assay, ROS was measured with DCFH-DA probe, MDA, and SOD content was evaluated through ELISA, NP cell apoptosis was tested by flow cytometry, protein expression was detected by Western blot, in particular, LC3 expression was assessed by immunofluorescence. In vivo, pathological changes were estimated by HE and safranin-O staining, related protein expression was measured by immunohistochemistry, and the apoptosis was detected by TUNEL. Compared with the control group, oxidative stress, apoptosis, and extracellular matrix (ECM) degradation were increased, the expression of cleaved caspase-3,9, aggrecan and collagen II were reduced, and the expression of MMP13 and ADAMTS5 were up-regulated in TBHP-treated NP cells. Moreover, TET could reverse the effect of TBHP on NP cells. Further, TET enhanced autophagy in NP cells by amplifying the LC3 II/LC3 I/ratio and reducing p62 expression, which attenuated oxidative stress, apoptosis, and ECM degradation in TBHP-treated NP cells. In addition, in vivo, TET delayed rat IDD, increased the expression of LC3 and collagen II, and weakened apoptosis. TET inhibited oxidative stress, apoptosis, and ECM degradation in TBHP-treated NP cells by inducing autophagy, and alleviated IDD. These indicated that TET might be a potential candidate drug for the treatment of IDD.

Strategies for Improving Photodynamic Therapy Through Pharmacological Modulation of the Immediate Early Stress Response

Photodynamic therapy (PDT) is a minimally to noninvasive treatment modality that has emerged as a promising alternative to conventional cancer treatments. PDT induces hyperoxidative stress and disrupts cellular homeostasis in photosensitized cancer cells, resulting in cell death and ultimately removal of the tumor. However, various survival pathways can be activated in sublethally afflicted cancer cells following PDT. The acute stress response is one of the known survival pathways in PDT, which is activated by reactive oxygen species and signals via ASK-1 (directly) or via TNFR (indirectly). The acute stress response can activate various other survival pathways that may entail antioxidant, pro-inflammatory, angiogenic, and proteotoxic stress responses that culminate in the cancer cell's ability to cope with redox stress and oxidative damage. This review provides an overview of the immediate early stress response in the context of PDT, mechanisms of activation by PDT, and molecular intervention strategies aimed at inhibiting survival signaling and improving PDT outcome.

Nanoparticle-Based Drug Delivery Systems for Photodynamic Therapy of Metastatic Melanoma: A Review

Metastatic melanoma (MM) is a skin malignancy arising from melanocytes, the incidence of which has been rising in recent years. It poses therapeutic challenges due to its resistance to chemotherapeutic drugs and radiation therapy. Photodynamic therapy (PDT) is an alternative non-invasive modality that requires a photosensitizer (PS), specific wavelength of light, and molecular oxygen. Several studies using conventional PSs have highlighted the need for improved PSs for PDT applications to achieve desired therapeutic outcomes. The incorporation of nanoparticles (NPs) and targeting moieties in PDT have appeared as a promising strategy to circumvent various drawbacks associated with non-specific toxicity, poor water solubility, and low bioavailability of the PSs at targeted tissues. Currently, most studies investigating new developments rely on two-dimensional (2-D) monocultures, which fail to accurately mimic tissue complexity. Therefore, three-dimensional (3-D) cell cultures are ideal models to resemble tumor tissue in terms of architectural and functional properties. This review examines various PS drugs, as well as passive and active targeted PS nanoparticle-mediated platforms for PDT treatment of MM on 2-D and 3-D models. The overall findings of this review concluded that very few PDT studies have been conducted within 3-D models using active PS nanoparticle-mediated platforms, and so require further investigation.

Oxidative Stress and Autophagy as Key Targets in Melanoma Cell Fate

Melanoma originates from the malignant transformation of melanocytes and is one of the most aggressive forms of cancer. The recent approval of several drugs has increased the chance of survival although a significant subset of patients with metastatic melanoma do not show a long-lasting response to these treatments. The complex cross-talk between oxidative stress and the catabolic process autophagy seems to play a central role in all aspects of melanoma pathophysiology, from initiation to progression and metastasis, including drug resistance. However, determining the fine role of autophagy in cancer death and in response to redox disruption is still a fundamental challenge in order to advance both basic and translational aspects of this field. In order to summarize the interactions among reactive oxygen and nitrogen species, autophagy machinery and proliferation/growth/death/apoptosis/survival, we provide here a narrative review of the preclinical evidence for drugs/treatments that modulate oxidative stress and autophagy in melanoma cells. The significance and the potential for pharmacological targeting (also through multiple and combination approaches) of these two different events, which can contribute independently or simultaneously to the fate of melanoma, may help to define new processes and their interconnections underlying skin cancer biology and unravel new reliable approaches.

Roles of the tumor suppressor inhibitor of growth family member 4 (ING4) in cancer

Inhibitor of growth family member 4 (ING4) is best known as a tumor suppressor that is frequently downregulated, deleted, or mutated in many cancers. ING4 regulates a broad array of tumor-related processes including proliferation, apoptosis, migration, autophagy, invasion, angiogenesis, DNA repair and chromatin remodeling. ING4 alters local chromatin structure by functioning as an epigenetic reader of H3K4 trimethylation histone marks (H3K4Me3) and regulating gene transcription through directing histone acetyltransferase (HAT) and histone deacetylase (HDAC) protein complexes. ING4 may serve as a useful prognostic biomarker for many cancer types and help guide treatment decisions. This review provides an overview of ING4's central functions in gene expression and summarizes current literature on the role of ING4 in cancer and its possible use in therapy.

Autophagy Regulation and Photodynamic Therapy: Insights to Improve Outcomes of Cancer Treatment

Cancer is considered an age-related disease that, over the next 10 years, will become the most prevalent health problem worldwide. Although cancer therapy has remarkably improved in the last few decades, novel treatment concepts are needed to defeat this disease. Photodynamic Therapy (PDT) signalize a pathway to treat and manage several types of cancer. Over the past three decades, new light sources and photosensitizers (PS) have been developed to be applied in PDT. Nevertheless, there is a lack of knowledge to explain the main biochemical routes needed to trigger regulated cell death mechanisms, affecting, considerably, the scope of the PDT. Although autophagy modulation is being raised as an interesting strategy to be used in cancer therapy, the main aspects referring to the autophagy role over cell succumbing PDT-photoinduced damage remain elusive. Several reports emphasize cytoprotective autophagy, as an ultimate attempt of cells to cope with the photo-induced stress and to survive. Moreover, other underlying molecular mechanisms that evoke PDT-resistance of tumor cells were considered. We reviewed the paradigm about the PDT-regulated cell death mechanisms that involve autophagic impairment or boosted activation. To comprise the autophagy-targeted PDT-protocols to treat cancer, it was underlined those that alleviate or intensify PDT-resistance of tumor cells. Thereby, this review provides insights into the mechanisms by which PDT can be used to modulate autophagy and emphasizes how this field represents a promising therapeutic strategy for cancer treatment.

Modeling the photodynamic effect in 2D versus 3D cell culture under normoxic and hypoxic conditions

BACKGROUND

Photodynamic therapy (PDT), mainly as a combined therapy, can still be considered a promising technology for targeted cancer treatment. Besides the several and essential benefits of PDT, there are some concerns and limitations, such as complex dosimetry, tumor hypoxia, and other mechanisms of resistance. In this study, we present how the cell culture model and cell culture conditions may affect the response to PDT treatment. It was studied by applying two different 3D cell culture, non-scaffold, and hydrogel-based models under normoxic and hypoxic conditions. In parallel, a detailed mechanism of the action of zinc phthalocyanine M2TG3 was presented.

METHODS

Hydrogel-based and tumor spheroids consisting of LNCaP cells, were used as 3D cell culture models in experiments performed under normoxic and hypoxic (1% of oxygen) conditions. Several analyses were performed to compare the activity of M2TG3 under different conditions, such as cytotoxicity, the level of proapoptotic and stress-related proteins, caspase activity, and antioxidant gene expression status. Additionally, we tested bioluminescence and fluorescence assays as a useful approach for a hydrogel-based 3D cell culture.

RESULTS

We found that M2TG3 might lead to apoptotic cancer cell death and is strongly dependent on the model and oxygen availability. Moreover, the expression of the genes modulated in the antioxidative system in 2D and 3D cell culture models were presented. The tested bioluminescence assay revealed several advantages, such as repetitive measurements on the same sample and simultaneous analysis of different parameters due to the non-lysing nature of this assay.

CONCLUSIONS

It was shown that M2TG3 can effectively cause cancer cell death via a different mechanism, depending on cell culture conditions such as the model and oxygen availability.

Cellular compartments challenged by membrane photo-oxidation

The lipid composition impacts directly on the structure and function of the cytoplasmic as well as organelle membranes. Depending on the type of membrane, specific lipids are required to accommodate, intercalate, or pack membrane proteins to the proper functioning of the cells/organelles. Rather than being only a physical barrier that separates the inner from the outer spaces, membranes are responsible for many biochemical events such as cell-to-cell communication, protein-lipid interaction, intracellular signaling, and energy storage. Photochemical reactions occur naturally in many biological membranes and are responsible for diverse processes such as photosynthesis and vision/phototaxis. However, excessive exposure to light in the presence of absorbing molecules produces excited states and other oxidant species that may cause cell aging/death, mutations and innumerable diseases including cancer. At the same time, targeting key compartments of diseased cells with light can be a promising strategy to treat many diseases in a clinical procedure called Photodynamic Therapy. Here we analyze the relationships between membrane alterations induced by photo-oxidation and the biochemical responses in mammalian cells. We specifically address the impact of photosensitization reactions in membranes of different organelles such as mitochondria, lysosome, endoplasmic reticulum, and plasma membrane, and the subsequent responses of eukaryotic cells.

Oxidative Stress and Photodynamic Therapy of Skin Cancers: Mechanisms, Challenges and Promising Developments

Ultraviolet radiation is one of the most pervasive environmental interactions with humans. Chronic ultraviolet irradiation increases the danger of skin carcinogenesis. Probably, oxidative stress is the most important mechanism by which ultraviolet radiation implements its damaging effects on normal cells. However, notwithstanding the data referring to the negative effects exerted by light radiation and oxidative stress on carcinogenesis, both factors are used in the treatment of skin cancer. Photodynamic therapy (PDT) consists of the administration of a photosensitiser, which undergoes excitation after suitable irradiation emitted from a light source and generates reactive oxygen species. Oxidative stress causes a condition in which cellular components, including DNA, proteins, and lipids, are oxidised and injured. Antitumor effects result from the combination of direct tumour cell photodamage, the destruction of tumour vasculature and the activation of an immune response. In this review, we report the data present in literature dealing with the main signalling molecular pathways modified by oxidative stress after photodynamic therapy to target skin cancer cells. Moreover, we describe the progress made in the design of anti-skin cancer photosensitisers, and the new possibilities of increasing the efficacy of PDT via the use of molecules capable of developing a synergistic antineoplastic action.

Inhibition of circulating exosomal microRNA-15a-3p accelerates diabetic wound repair

Diabetic foot ulcers are a common complication of diabetes, and are usually incurable in the clinic. Exosomes (carriers that transfer endogenous molecules) from diabetic patients' blood have been demonstrated to suppress diabetic wound repair. In this study, we investigated the effects of circulating exosomal microRNA-15a-3p (miR-15a-3p) on diabetic wound repair. Exosomes were extracted from diabetic patients' blood, and were found to inhibit diabetic wound repair in vitro and in vivo. miR-15a-3p was upregulated in diabetic exosomes, and impaired wound healing. When miR-15a-3p was knocked down in diabetic exosomes, their negative effects were partially reversed both in vitro and in vivo. NADPH oxidase 5 (NOX5) was identified as a potential target of miR-15a-3p, and the inhibition of NOX5 reduced the release of reactive oxygen species, thereby impairing the functionality of human umbilical vein endothelial cells. In summary, inhibition of circulating exosomal miR-15a-3p accelerated diabetic wound repair by activating NOX5, providing a novel therapeutic target for diabetic foot ulcer therapy.