Unleashing the power of porphyrin photosensitizers: Illuminating breakthroughs in photodynamic therapy

This comprehensive review provides the current trends and recent developments of porphyrin-based photosensitizers. We discuss their evolution from first-generation to third-generation compounds, including cutting-edge nanoparticle-integrated derivatives, and explores their pivotal role in advancing photodynamic therapy (PDT) for enhanced cancer treatment. Integrating porphyrins with nanoparticles represents a promising avenue, offering improved selectivity, reduced toxicity, and heightened biocompatibility. By elucidating recent breakthroughs, innovative methodologies, and emerging applications, this review provides a panoramic snapshot of the dynamic field, addressing challenges and charting prospects. With a focus on harnessing reactive oxygen species (ROS) through light activation, PDT serves as a minimally invasive therapeutic approach. This article offers a valuable resource for researchers, clinicians, and PDT enthusiasts, highlighting the potential of porphyrin photosensitizers to improve the future of cancer therapy.

Peptide-Conjugated Nano Delivery Systems for Therapy and Diagnosis of Cancer

Peptides are strings of approximately 2-50 amino acids, which have gained huge attention for theranostic applications in cancer research due to their various advantages including better biosafety, customizability, convenient process of synthesis, targeting ability via recognizing biological receptors on cancer cells, and better ability to penetrate cell membranes. The conjugation of peptides to the various nano delivery systems (NDS) has been found to provide an added benefit toward targeted delivery for cancer therapy. Moreover, the simultaneous delivery of peptide-conjugated NDS and nano probes has shown potential for the diagnosis of the malignant progression of cancer. In this review, various barriers hindering the targeting capacity of NDS are addressed, and various approaches for conjugating peptides and NDS have been discussed. Moreover, major peptide-based functionalized NDS targeting cancer-specific receptors have been considered, including the conjugation of peptides with extracellular vesicles, which are biological nanovesicles with promising ability for therapy and the diagnosis of cancer.

Effect of vitamin A as a neoadjuvant agent in chemotherapy and photodynamic therapy of Rhabdomyosarcoma cells

Combinational therapy is among the most used treatment modality's to increase cancer treatment efficacy. It may also reduce side effects, treatment time, and development of drug resistance. The effects of different analogues of vitamin A (VA) as neoadjuvant agent were observed in this study with chemotherapeutic drugs (doxorubicin and methotrexate) and photodynamic therapy (PDT) using 5-ALA and Photogem as photosensitizers in RD cells. The uptake time of photosensitizer was optimized by means of spectrophotometric measurements. Diode laser (λ = 635 nm ± 1 nm) was used as an illumination source for PDT. Responses of administered drugs were assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. VA and its analogues exert prophylactic and therapeutic effects. Protective or antagonistic effects (CI > 1) were observed in each of the case. These results propose that the use of VA as a neoadjuvant agent in combinational therapeutic modalities may reduce the efficacy of cancer treatment protocols as well as the existing side effects. Thus, VA is not the successful drug for combinational therapies and under treatment cancer patients should try to avoid its use with oxidative stress induction therapies (e.g. PDT, Radiotherapy, chemotherapy).

Novel Analgesics with Peripheral Targets

A limited number of peripheral targets generate pain. Inflammatory mediators can sensitize these. The review addresses targets acting exclusively or predominantly on sensory neurons, mediators involved in inflammation targeting sensory neurons, and mediators involved in a more general inflammatory process, of which an analgesic effect secondary to an anti-inflammatory effect can be expected. Different approaches to address these systems are discussed, including scavenging proinflammatory mediators, applying anti-inflammatory mediators, and inhibiting proinflammatory or facilitating anti-inflammatory receptors. New approaches are contrasted to established ones; the current stage of progress is mentioned, in particular considering whether there is data from a molecular and cellular level, from animals, or from human trials, including an early stage after a market release. An overview of publication activity is presented, considering a IuPhar/BPS-curated list of targets with restriction to pain-related publications, which was also used to identify topics.

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.

New RuII pincer complexes: synthesis, characterization and biological evaluation for photodynamic therapy

Three new ruthenium(ii) complexes of NCN pincer and phenylcyanamide derivative ligands of the formula [Ru(L)(Ph₂phen)(3,5-(NO₂)₂pcyd)], 1, [Ru(L)(Me₂phen)(3,5-(NO₂)₂pcyd)], 2, and [Ru(L)(Cl₂phen)(3,5-(NO₂)₂pcyd)], 3 (HL: 5-methoxy-1,3-bis(1-methyl-1H-benzo[d]imidazol-2-yl)benzene, 3,5-(NO₂)₂pcyd: 3,5-(NO₂)₂pcyd, Ph₂phen: 4,7-diphenyl-1,10-phenanthroline, Me₂phen: 4,7-dimethyl-1,10-phenanthroline, Cl₂phen: 4,7-dichloro-1,10-phenanthroline) have been synthesized and studied as potential photosensitizers (PSs) in photodynamic therapy (PDT). The complexes exhibited promising ¹O₂ production quantum yields comparable with PSs available on the market. The DNA-binding interactions of the complexes with calf thymus DNA have been studied by absorption, emission, and viscosity measurements. All complexes cleave SC-DNA efficiently on photoactivation at 350 nm with the formation of singlet oxygen (¹O₂) and hydroxyl radicals (˙OH) in type-II and photoredox pathways. Complexes 1-3 showed very good uptake in cervical cancer cells (HeLa). The compounds studied were found to exhibit low toxicity against HeLa cells (IC₅₀ > 300 μM) and, remarkably, on non-cancerous MRC-5 cells (IC₅₀ > 100 μM) in the dark. However, 1 showed very promising behavior with an increment of about 90 times, in its cytotoxicity upon light illumination at 420 nm in addition to very good human plasma stability.

Reactive Oxygen Species and NOX Enzymes Are Emerging as Key Players in Cutaneous Wound Repair

Our understanding of the role of oxygen in cell physiology has evolved from its long-recognized importance as an essential factor in oxidative metabolism to its recognition as an important player in cell signaling. With regard to the latter, oxygen is needed for the generation of reactive oxygen species (ROS), which regulate a number of different cellular functions including differentiation, proliferation, apoptosis, migration, and contraction. Data specifically concerning the role of ROS-dependent signaling in cutaneous wound repair are very limited, especially regarding wound contraction. In this review we provide an overview of the current literature on the role of molecular and reactive oxygen in the physiology of wound repair as well as in the pathophysiology and therapy of chronic wounds, especially under ischemic and hyperglycemic conditions.

Porphyrin photosensitizers in photodynamic therapy and its applications

In 1841, the extraction of hematoporphyrin from dried blood by removing iron marked the birth of the photosensitizer. The last twenty years has witnessed extensive research in the application of photodynamic therapy (PDT) in tumor-bearing (or other diseases) animal models and patients. The period has seen development of photosensitizers from the first to the third generation, and their evolution from simple to more complex entities. This review focuses on porphyrin photosensitizers and their effect on tumors, mediated via several pathways involved in cell necrosis, apoptosis or autophagic cell death, and the preventive and therapeutic application of PDT against atherosclerosis.

In vivosilymarin’s antioxidant and anti-apoptotic effects on photodynamic therapy’s responsiveness

Several studies have shown that some anti-oxidant natural compounds in combination with photodynamic therapy (PDT) can enhance the effectiveness of treatment. The aim of this study is to evaluate the effect of silymarin (SIL) in combination with 5,10,15,20-tetra-sulphonato-phenyl-porphyrin (TSPP) based photodynamic therapy, on experimental tumors. 30 Wistar rats with Walker carcinosarcoma, were divided into 6 groups: group 0 (control) — control, untreated group; group 1 (TSPP) — one dose of TSPP; group 2 (SIL) — silymarin; group 3 (PDT) — TSPP and irradiation 24 h after; group 4 (SIL[Formula: see text]PDT) — silymarin, TSPP and irradiation 24 h after; group 5 (SIL[Formula: see text]IR) and group 6 (IR) — irradiation and in addition, group 5 received SIL. Silymarin administered before photodynamic therapy decreased the lipid peroxidation ([Formula: see text] < 0.05) and modulated the antioxidant defense in tumor treated with PDT and silymarin suggesting that silymarin administration along with photodynamic therapy has an anti-oxidant effect. The caspase — 8 level and -3 activity increased in PDT and PDT [Formula: see text] SIL groups compared to the control; between the two groups there was a significant difference in term of apoptosis in favor to PDT. In conclusion, silymarin administration inhibited the reactive oxygen species generation and reduced the tumoral cells’ apoptosis, suggesting that natural compound administered before photodynamic therapy did not improve the therapy’s effect.

BODIPY appended copper(ii) complexes of curcumin showing mitochondria targeted remarkable photocytotoxicity in visible light

BODIPY-appended copper(ii) complexes of curcumin show a remarkable PDT effect in visible light in HeLa cellsviaapoptosis with mitochondrial localization.

Metformin associated with photodynamic therapy--a novel oncological direction

The aim of our study was to assess the effect of the combined treatment of Metformin (Metf) and 5, 10, 15, 20-tetra-sulfophenyl-porphyrin (TSPP)-mediated photodynamic therapy (PDT) on an in vivo tumour model. Wistar male rats were divided in 6 groups: group 1, treated with TSPP; groups 2 and 4 treated with TSPP and Metf, respectively, and irradiated 24h thereafter; group 3 was treated with Metf and the last two groups received the combined treatment, Metf administered prior (group 5) or after (group 6) irradiation. 72 h from the start of the treatment, tumour tissue was sampled for the investigation of oxidative and nitrosative stress. The apoptotic rate, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expressions and matrix metalloproteinases activities were also quantified. Malondialdehyde and glutathione levels were significantly elevated in the groups treated with combined therapy (p<0.05). Metf associated with TSPP-PDT reduced iNOS and COX-2 expressions and enhanced nitrotyrosine levels in both therapeutic regimens. Peroxynitrate formation and its cytotoxic effect on tumour cells were related to an elevated index of apoptosis and necrosis. Moreover, MMP-2 activity reached a minimum in the groups which received combined therapy. Our results confirmed that the association of Metf with PDT might prove a new and promising oncological approach.

Oxidative stress effects of fullerene-porphyrin derivatives in photodynamic therapy

Due to their special and growing medical recent interest, the fullerenes started to be a very studied class of chemical compounds. In order to improve their water solubility and to reduce their cytotoxic characteristics, the fullerenes have been coupled in a system fullerene/PVP/porphyrin (C60/PVP/TPP) and its application in photodynamic therapy will be evaluated in this paper. The oxidative stress effects on photodynamic therapy with systems fullerene/poly-N-vinylpirrolidone/5,10,15,20-tetrakis(4-phenyl)porphyrin (C60/PVP/TPP) were tested on Wistar rats sub-cutaneously inoculated with Walker 256 carcinoma. The animals were irradiated with red light (λ = 685 nm; D = 50 J/cm2; 15 minutes) 24 h after intra-peritoneal administration of 10 mg/kg body weight of the system C60/PVP/TPP. After photodynamic therapy, the free radicals in tumors have been indirectly evaluated by lipid peroxides level (measured as thiobarbituric reactive substances) and protein carbonyls (indices of oxidative effects produced on susceptible biomolecules), both of them increasing in tumor tissues of animals 24 h after treatment. The levels of thiol groups and total antioxidant capacity have been determined in tumors, too, their decreasing values being the effect of the strong tumoral oxidative process.

Possible in vivo mechanisms involved in photodynamic therapy using tetrapyrrolic macrocycles

Photodynamic therapy (PDT) mediated by oxidative stress causes direct tumor cell damage as well as microvascular injury. To improve this treatment new photosensitizers are being synthesized and tested. We evaluated the effects of PDT with 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin (TMPP) and its zinc complex (ZnTMPP) on tumor levels of malondialdehyde (MDA), reduced glutathione (GSH) and cytokines, and on the activity of caspase-3 and metalloproteases (MMP-2 and -9) and attempted to correlate them with the histological alterations of tumors in 3-month-old male Wistar rats, 180 ± 20 g, bearing Walker 256 carcinosarcoma. Rats were randomly divided into five groups: group 1, ZnTMPP+irradiation (IR) 10 mg/kg body weight; group 2, TMPP+IR 10 mg/kg body weight; group 3, 5-aminolevulinic acid (5-ALA+IR) 250 mg/kg body weight; group 4, control, no treatment; group 5, only IR. The tumors were irradiated for 15 min with red light (100 J/cm², 10 kHz, 685 nm) 24 h after drug administration. Tumor tissue levels of MDA (1.1 ± 0.7 in ZnTMPP vs 0.1 ± 0.04 nmol/mg protein in control) and TNF-α (43.5 ± 31.2 in ZnTMPP vs 17.3 ± 1.2 pg/mg protein in control) were significantly higher in treated tumors than in controls. Higher caspase-3 activity (1.9 ± 0.9 in TMPP vs 1.1 ± 0.6 OD/mg protein in control) as well as the activation of MMP-2 (P < 0.05) were also observed in tumors. These parameters were correlated (Spearman correlation, P < 0.05) with the histological alterations. These results suggest that PDT activates the innate immune system and that the effects of PDT with TMPP and ZnTMPP are mediated by reactive oxygen species, which induce cell membrane damage and apoptosis.