Iron chelation promotes 5-aminolaevulinic acid-based photodynamic therapy against oral tongue squamous cell carcinoma

Preparation of protoporphyrin IX loaded nanostructured lipid carriers for anticancer photodynamic therapy

Photodynamic therapy (PDT) is a promising strategy for cancer treatment. However, the poor hydrophilicity of most photosensitizers makes them difficult to enter the cells and also susceptible to aggregation-induced quenching in aqueous environment. In this study, we encapsulated protoporphyrin IX (PPIX) by nanostructured lipid carrier to obtain a water-soluble PPIX delivery system (NLC-PPIX). The nanoparticles exhibited high colloidal stability and good fluorescence emission. The generation of 1O2 from the NLC-PPIX was verified using 9,10-anthracenediyl-bis(methylene)dicarboxylic acid (ABDA) as 1O2 indicator. The 1O2 quantum yield of the NLC-PPIX in aqueous solution was calculated to be ∼9%. The flow cytometry and fluorescence imaging confirmed the uptake of NLC-PPIX by the A2058 cells and the generation of 1O2 inside the cells under light excitation. The in vitro cytotoxicity assay showed that the NLC-PPIX exerted no toxicity on the A2058 cells under dark conditions, while light irradiation triggered high phototoxicity. The cell viability of the A2058 cells was significantly decreased and the inhibition rate reached approximately 96% by treating the cells with 200 μg/mL NLC-PPIX and 420 nm light irradiation. The successful cancer cell uptake and PDT effect revealed the therapeutic promise of our drug delivery system.

Noninvasive Ultra Low Intensity Light Photodynamic Treatment of Glioblastoma with Drug Augmentation: LoGlo PDT Regimen

This paper presents the basis for LoGlo PDT, a new treatment for glioblastoma. Glioblastoma is currently treated with maximal safe resection, temozolomide, and ionizing irradiation. Mortality in 2024 remains over 80% within several years from diagnosis. Oral 5-aminolevulinic acid (5-ALA) is an FDA/EMA approved drug that is selectively taken up by malignant cells, including by glioblastoma. In photodynamic treatment of glioblastoma, intense intraoperative light causes glioblastoma tissue that has taken up 5-ALA to generate cytotoxic reactive oxygen species. The requirement for intense light flux has restricted photodynamic treatment to a single one-hour intraoperative session. We analyze here published data showing that external light, illuminating the entire intact scalp, can attain low μW/cm2 flux several cm into intact brain that would be sufficient to mediate 5-ALA photodynamic treatment of glioblastoma if the light and 5-ALA are delivered continuously over 24 h. At the core of LoGlo PDT regimen is the dataset showing that, for a given fluence, as the duration of PDT light delivery goes down, light intensity (flux) delivered must go up to achieve the same glioblastoma cell cytotoxicity as would a weaker light (lower flux) delivered over a longer time. Thus, a repetitive, noninvasive PDT of glioblastoma using an external light source may be possible. We analyze 5-ALA cellular physiology to show that three non-oncology drugs, ciprofloxacin, deferiprone, and telmisartan, can be repurposed to increase light energy capture after 5-ALA, thereby increasing photodynamic treatment's glioblastoma cell cytotoxicity. The LoGlo PDT approach uses both drug augmentation and prolonged ultra-low noninvasive transcranial light delivery for a repetitive, noninvasive 5-ALA photodynamic treatment of glioblastoma.

Photodynamic Therapy for Oral Squamous Cell Carcinoma: Current Status, Challenges, and Prospects

Oral squamous cell carcinoma (OSCC) is the most prevalent and deadly malignancy of the head and neck. The standard treatments for OSCC are surgery, radiotherapy, and chemoradiotherapy, which can cause severe cosmetic and functional damage to the oral cavity and impair the patients' quality of life. Photodynamic therapy (PDT) is a promising alternative that uses light-activated photosensitizers to induce selective phototoxicity and necrosis in the target tissues. PDT has several advantages over conventional treatments, such as minimal invasion, low side effects, high selectivity and preservation of the oral function and appearance. This review explores the principles, mechanisms, and current applications of PDT for OSCC. We address the challenges, such as the depth of light penetration and tissue hypoxia, and underscore the progressive innovations in photosensitizer enhancement, nanotechnological integration, and precision therapy. The exploration of biomarkers for refining patient selection and tailoring individualized treatment regimens is also undertaken. PDT holds promise as a secure and efficacious modality for OSCC management. Nonetheless, additional investigation is imperative to refine treatment protocols and validate sustained therapeutic success.

Iron Metabolism in Aminolevulinic Acid-Photodynamic Therapy with Iron Chelators from the Thiosemicarbazone Group

Iron plays a crucial role in various metabolic processes. However, the impact of 5-aminolevulinic acid (ALA) in combination with iron chelators on iron metabolism and the efficacy of ALA-photodynamic therapy (PDT) remain inadequately understood. This study aimed to examine the effect of thiosemicarbazone derivatives during ALA treatment on specific genes related to iron metabolism, with a particular emphasis on mitochondrial iron metabolism genes. In our study, we observed differences depending on the cell line studied. For the HCT116 and MCF-7 cell lines, in most cases, the decrease in the expression of selected targets correlated with the increase in protoporphyrin IX (PPIX) concentration and the observed photodynamic effect, aligning with existing literature data. The Hs683 cell line showed a different gene expression pattern, previously not described in the literature. In this study, we collected an extensive analysis of the gene variation occurring after the application of novel thiosemicarbazone derivatives and presented versatile and effective compounds with great potential for use in ALA-PDT.

Enhancing 5-ALA-PDT efficacy against resistant tumor cells: Strategies and advances

As a precursor of protoporphyrin IX (PpIX), an endogenous pro-apoptotic and fluorescent molecule, 5-Aminolevulinic acid (5-ALA) has gained substantial attention for its potential in fluorescence-guided surgery as well as photodynamic therapy (PDT). Moreover, 5-ALA-PDT has been suggested as a promising chemo-radio sensitization therapy for various cancers. However, insufficient 5-ALA-induced PpIX fluorescence and the induction of multiple resistance mechanisms may hinder the 5-ALA-PDT clinical outcome. Reduced efficacy and resistance to 5-ALA-PDT can result from genomic alterations, tumor heterogeneity, hypoxia, activation of pathways related to cell surveillance, production of nitric oxide, and most importantly, deregulated 5-ALA transporter proteins and heme biosynthesis enzymes. Understanding the resistance regulatory mechanisms of 5-ALA-PDT may allow the development of effective personalized cancer therapy. Here, we described the mechanisms underlying resistance to 5-ALA-PTD across various tumor types and explored potential strategies to overcome this resistance. Furthermore, we discussed future approaches that may enhance the efficacy of treatments using 5-ALA-PDT.

Nanomaterials-based advanced systems for photothermal / photodynamic therapy of oral cancer

The traditional clinical approaches for oral cancer consist of surgery, chemotherapy, radiotherapy, immunotherapy, and so on. However, these treatments often induce side effects and exhibit limited efficacy. Photothermal therapy (PTT) emerges as a promising adjuvant treatment, utilizing photothermal agents (PTAs) to convert light energy into heat for tumor ablation. Another innovative approach, photodynamic therapy (PDT), leverages photosensitizers (PSs) and specific wavelength laser irradiation to generate reactive oxygen species (ROS), offering an effective and non-toxic alternative. The relevant combination therapies have been reported in the field of oral cancer. Simultaneously, the advancement of nanomaterials has propelled the clinical application of PTT and PDT. Therefore, a comprehensive understanding of PTT and PDT is required for better application in oral cancer treatment. Here, we review the use of PTT and PDT in oral cancer, including noble metal materials (e.g., Au nanoparticles), carbon materials (e.g., graphene oxide), organic dye molecules (e.g., indocyanine green), organic molecule-based agents (e.g., porphyrin-analog phthalocyanine) and other inorganic materials (e.g., MXenes), exemplify the advantages and disadvantages of common PTAs and PSs, and summarize the combination therapies of PTT with PDT, PTT/PDT with chemotherapy, PTT with radiotherapy, PTT/PDT with immunotherapy, and PTT/PDT with gene therapy in the treatment of oral cancer. The challenges related to the PTT/PDT combination therapy and potential solutions are also discussed.

In vitro modeling of recurrent Dermatofibrosarcoma Protuberans: Assessment of 5-aminolevulinic acid photodynamic therapy efficacy

BACKGROUND

Dermatofibrosarcoma Protuberans (DFSP) is a rare, low-grade malignant tumor of the dermis with a high recurrence rate post-surgery. Current treatments, including surgery, radiotherapy, and targeted therapy, have limitations. Photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) is a promising non-invasive approach, but its efficacy in DFSP treatment remains underexplored.

METHODS

This study aimed to evaluate the anti-tumor efficacy of 5-ALA PDT using an in vitro model derived from a recurrent DFSP patient. The cells were treated with varying concentrations of 5-ALA and exposed to red light, followed by assessments of cell viability, proliferation, apoptosis, migration, invasion, angiogenesis, and expression of DFSP-related genes and proteins.

RESULTS

5-ALA PDT significantly reduced DFSP cell viability in a dose-dependent manner and induced apoptosis. It also effectively inhibited cell proliferation, migration, and invasion, as well as suppressed angiogenic activity in conditioned media. Furthermore, 5-ALA PDT downregulated the expression of COL1A1 and PDGFRB, key genes in DFSP pathogenesis.

CONCLUSIONS

The findings provide the first evidence of 5-ALA PDT's in vitro anti-tumor efficacy against DFSP, suggesting its potential as a novel therapeutic approach for DFSP. Further studies are warranted to explore the clinical utility of 5-ALA PDT in preventing DFSP recurrence.

5-Aminolevulinic Acid as a Theranostic Agent for Tumor Fluorescence Imaging and Photodynamic Therapy

5-Aminolevulinic acid (ALA) is a naturally occurring amino acid synthesized in all nucleated mammalian cells. As a porphyrin precursor, ALA is metabolized in the heme biosynthetic pathway to produce protoporphyrin IX (PpIX), a fluorophore and photosensitizing agent. ALA administered exogenously bypasses the rate-limit step in the pathway, resulting in PpIX accumulation in tumor tissues. Such tumor-selective PpIX disposition following ALA administration has been exploited for tumor fluorescence diagnosis and photodynamic therapy (PDT) with much success. Five ALA-based drugs have now received worldwide approval and are being used for managing very common human (pre)cancerous diseases such as actinic keratosis and basal cell carcinoma or guiding the surgery of bladder cancer and high-grade gliomas, making it the most successful drug discovery and development endeavor in PDT and photodiagnosis. The potential of ALA-induced PpIX as a fluorescent theranostic agent is, however, yet to be fully fulfilled. In this review, we would like to describe the heme biosynthesis pathway in which PpIX is produced from ALA and its derivatives, summarize current clinical applications of ALA-based drugs, and discuss strategies for enhancing ALA-induced PpIX fluorescence and PDT response. Our goal is two-fold: to highlight the successes of ALA-based drugs in clinical practice, and to stimulate the multidisciplinary collaboration that has brought the current success and will continue to usher in more landmark advances.

Insight on nano drug delivery systems with targeted therapy in treatment of oral cancer

Oral cancer is a type of cancer that develops in the mouth and is one of the deadliest malignancies in the world. Currently surgical, radiation therapy, and chemotherapy are most common treatments. Better treatment and early detection strategies are required. Chemotherapeutic drugs fail frequently due to toxicity and poor tumor targeting. There are high chances of failure of chemotherapeutic drugs due to toxicity. Active, passive, and immunity-targeting techniques are devised for tumor-specific activity. Nanotechnology-based drug delivery systems are the best available solution and important for precise targeting. Nanoparticles, liposomes, exosomes, and cyclodextrins are nano-based carriers for drug delivery. Nanotechnology is being used to develop new techniques such as intratumoral injections, microbubble mediated ultrasonic therapy, phototherapies, and site-specific delivery. This systematic review delves into the details of such targeted and nano-based drug delivery systems in order to improve patient health and survival rates in oral cancer.

Effects of Iron on Efficacy of Photodynamic Therapy Using Photolon in a Mouse Model of CT26 Colon Cancer

BACKGROUND

Photodynamic therapy (PDT) -a minimally invasive anti-cancer therapy-is undergoing experimental studies to increase its anti-cancer effects. This study investigated the influence of iron on the anti-cancer effects of PDT.

METHODS

PDT was performed in a cancer-bearing mouse model, which was created by using a murine colon carcinoma (CT26) cell line after administration of Photolon and iron. Tumor volume and the results of TdT-mediated dUTP-biotin nick end labeling (TUNEL), 8-OHdG, and TBARS assays were used to measure anti-cancer effect.

RESULTS

On day 14, tumor volume had increased by 49% in the PDT group and decreased by 72% in the iron+PDT group. The percentage of TUNEL-positive cells in tumor tissues was 45% in the PDT group and 69% in the iron+PDT group, suggesting that the proportion of TUNEL-positive cells had increased in the iron+PDT group. The 8-OHdG content in tumor tissues was 33% higher in the iron+PDT group than in the PDT group. The TBARS content in tumor tissues was 46% higher in the iron+PDT group than in the PDT group.

CONCLUSIONS

Iron enhances the anti-cancer effect of PDT using Photolon, most likely by increasing oxidative damage.

A Multifunctional Nanosystem Based on Bacterial Cell-Penetrating Photosensitizer for Fighting Periodontitis Via Combining Photodynamic and Antibiotic Therapies

Photodynamic therapy (PDT), an emerging approach that involves photosensitizers, light, and molecular oxygen, has shown promise for fighting periodontitis. However, PDT does not always acquire the desired therapeutic outcomes since some photosensitizers have strong hydrophobic properties and are difficult to absorb efficiently by periodontal pathogenic bacteria. Here, a hydrophobic photosensitizer chlorin e6 (Ce6) was hydrophilically modified via conjugation with TAT peptide, a cationic cell-penetrating peptide, to improve its solubility and enhance its bacterial adsorption by promoting its interaction with the negatively charged cell walls and penetration through the cell membranes. The obtained TAT-Ce6 conjugate (TAT-Ce6) was used to prepare self-assembled nanoparticles (NPs) for loading tinidazole (TDZ), a clinically used antibiotic agent, thus hoping to achieve synergistic antiperiodontitis effects through combining PDT and antibiotic therapy. Compared to free Ce6, TAT-Ce6 nanoparticles (TAT-Ce6 NPs) had greatly enhanced adsorption and penetration abilities for periodontal pathogen bacteria and also exhibited significantly increased PDT efficiencies in both periodontal pathogen bacteria and monocyte macrophages. Upon 635 nm laser irradiation, TDZ-loaded TAT-Ce6 (TAT-Ce6/TDZ) NPs exerted remarkable synergistic antiperiodontitis effects of PDT and antibiotic therapy, reflecting in the effective killing of periodontal pathogenic bacteria in vitro and the reduced adsorption of alveolar bone in the Sprague-Dawley rat model of periodontitis. Altogether, this study develops a novel photosensitizer that can be efficiently absorbed by the periodontal pathogenic bacteria and also provides a potent combination strategy of PDT with antibiotic therapy for clinical periodontitis treatment.