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Background: 5-aminolevulinic acid photodynamic therapy (ALA-PDT) has received growing attention for treating chromoblastomycosis (CBM) and has shown efficacy in a handful of clinical case reports. However, there is insufficient information regarding the effects of ALA-PDT on Fonsecaea monophora in mouse infection model and the related mechanisms. This study investigated these issues in vivo., Methods: A F. monophora infection mouse model inoculated in footpads was used. Changes in the footpad volume, tissue fungal burden, and histopathological characteristics were investigated to determine the efficacy of ALA-PDT. Scavenger receptor MARCO (Macrophage receptor with collagenous structure) was further evaluated at the gene and protein levels. Serum cytokines TNF-α, GM-CSF, IL-4, and IL-10 were measured using enzyme-linked immunosorbent assay to indicate changes in the immune microenvironment after PDT., Results: ALA-PDT reduced infected footpad volume, fungal burden, and pathological inflammatory infiltration in vivo. It also increased the expression of Marco in the murine infection model. Furthermore, PDT upregulated the anti-inflammatory cytokines IL-4 and IL-10 while downregulated the pro-inflammatory cytokines TNF-α and GM-CSF in mouse serum., Conclusions: ALA-PDT demonstrated fungicidal effects in a mouse footpad infection model with F. monophora and attenuated the inflammatory reactions. It may also assist against the intracellular fungi by the host through macrophage receptor MARCO and regulation of the immune microenvironment. This study provides scientific evidence for the protocol selection of ALA-PDT as a promising adjunctive modality for treating chromoblastomycosis., Competing Interests: Disclosure statement The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Herpes simplex virus (HSV) infections are prevalent worldwide, posing challenges due to asymptomatic carriage and recurrent outbreaks. Conventional treatments, including antiviral medications, are limited by drug resistance. Photodynamic therapy (PDT) offers a promising alternative, leveraging photosensitizers to induce viral inactivation via reactive oxygen species (ROS) generation upon light activation., Methods: This study investigates the efficacy of 5-aminolevulinic acid (5-ALA) as a photosensitizer in antiviral PDT against HSV-1. HSV-1 was treated with varying concentrations of 5-ALA and subjected to light irradiation at a 630 nm wavelength. Virus titers were assessed using the 50 % Tissue Culture Infectious dose (TCID50) assay. Six experimental groups were used: [1] Control (no 5-ALA or light), HSV-1 with 0.05 g/ml 5-ALA and 630 nm light, [2] HSV-1 with 0.05 g/ml 5-ALA (no light), [3] HSV-1 with 0.1 g/ml 5-ALA and light, [4] HSV-1 with 0.1 g/ml 5-ALA (no light), and [5] HSV-1 with light (no 5-ALA)., Results: Virus treatment with 0.1 g/ml 5-ALA combined with light irradiation significantly reduced HSV-1 titer compared to control groups (p < 0.05). Specifically, the virus titer decreased from 10 6.3 TCID50/ml in the control group to 10 4.5 TCID50/ml in the treated group. However, lower concentrations of 5-ALA or light irradiation alone did not yield significant reductions in HSV-1 titer (p > 0.05). Group 4, receiving 0.1 g/ml 5-ALA with light irradiation, exhibited a significantly greater reduction in virus titer than group 2, receiving 0.05 g/ml 5-ALA with light irradiation (p < 0.05)., Conclusions: 5-ALA-mediated PDT demonstrates selective antiviral efficacy against HSV-1, particularly at higher concentrations coupled with light irradiation. These findings underscore the potential of 5-ALA-based PDT as a promising approach for HSV-1 treatment, especially in cases of drug-resistant strains and immunocompromised individuals. Optimization of dosage and treatment protocols is essential for maximizing effectiveness in clinical applications, highlighting the need for further research in this area., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Mycobacterium abscessus skin infections have emerged as a major medical issue. Traditional antibiotic treatments are challenging, prolonged, and often lead to recurrence, creating an urgent need for new therapies. This study investigates the effectiveness of aminolevulinic acid photodynamic therapy (ALA-PDT) combined with antibiotics in treatmenting M. abscessus, using both in vitro and in vivo methods., Methods: We treated eight patients with M. abscessus skin infections following cosmetic surgery, using ALA-PDT (ALA concentration: 20 %; red light: 80 J/cm 2 ) combined with oral or intravenous antibiotics,including clarithromycin, moxifloxacin and amikacin, to treat 8 patients with M. abscessus skin infection after medical cosmetic surgery, and assessed the treatment outcomes. Additionally, four bacterial strains (MAB-A1, MAB-A2, MAB-B1, and MAB-B2) isolated from patients were tested in vitro for ALA-PDT efficacy to determine the optimal ALA-PDT dosage. Furthermore, the strains' single colony morphology, biofilm formation, and genome characteristics of were analyzed to explore the factors influencing ALA-PDT's bactericidal effects. Finally, a combined ALA-PDT and antibiotics sterilization experiment was conducted in vitro., Results: Clinically, ALA-PDT combined with antibiotics showed strong efficacy in treating M. abscessus skin infections, with no recurrence observed during follow-up. In vitro, ALA-PDT effectively killed M. abscessus, although MAB-B1 and MAB-B2 required a higher ALA-PDT dose compared with MAB-A1 and MAB-A2. Compared to MAB-A1 and MAB-A2, MAB-B1 and MAB-B2 exhibited stronger biofilm formation capabilities and bacterial virulence as well as genome mutations primarily affecting fatty acid synthesis and metabolism, potentially explaining their increased ALA-PDT dosage requirement. Notably, the combination of ALA-PDT and antibiotics exerted markedly higher bactericidal effects in vitro compared with antibiotics alone., Conclusions: ALA-PDT combined with antibiotics emerged as an effective treatment for M. abscessus skin infections. However, optimal dosage and antibiotic combinations should be tailored to the characteristics of specific clinical strains., Competing Interests: Declaration of competing interest No conflict of interests exits in the submission of this manuscript, and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the listed authors have approved the manuscript that is enclosed. Xiaoyu Wang, Xiao Wang, Zhenyu Kou, Kedai Sun, Yang Tan, Jinyi Chen, Yang He, Wen Ding, Hong Liu, Yi Liang, Lingfei Li, Xia Lei., (Copyright © 2024. Published by Elsevier B.V.)

The use of 5-aminolevulinic acid (ALA) as a precursor for protoporphyrin IX (PpIX) is an established photosensitization strategy for photodynamic therapy (PDT) and fluorescence guided surgery. Ongoing studies are focused on identifying approaches to enhance PpIX accumulation as well as to identify tumor sub-types associated with high PpIX accumulation. In this study, we investigated PpIX accumulation and PDT treatment response with respect to nodule size in 3D cultures of pancreatic cancer cells (Panc1) and a derivative subline (Panc1OR), which has acquired drug resistance and exhibits increased epithelial mesenchymal transition. In monolayer and 3D culture dose response studies the Panc1OR cells exhibit significantly a higher level of photokilling at lower light doses than the drug naïve cells. Panc1OR also exhibits increased PpIX accumulation. Further analysis of cell killing efficiency per molecule of intracellular PpIX indicates that the drug resistant cells are intrinsically more responsive to PDT. Additional investigation using exogenous delivery of PpIX also shows higher cell killing in drug resistant cells, under conditions which achieve approximately the same intracellular PpIX. Overall these results are significant as they demonstrate that this example of drug-resistant cells associated with aggressive disease progression and poor clinical outcomes, show increased sensitivity to ALA-PDT., (Copyright © 2024. Published by Elsevier B.V.)

Background: Cervical cancer ranks the fourth most prevalent type of cancer worldwide, characterized by a notably low survival rate, particularly in its metastatic stage. Despite 5-aminolevulinic acid photodynamic therapy (ALA-PDT) demonstrating potential anti-tumor effects against cervical cancer, the intricate mechanisms underlying its efficacy necessitate further investigation. Here, the study aims to elucidate the impact of ALA-PDT on the cancer cell viability, invasion and migration, alongside delineating the underlying molecular mechanisms., Methods: Cervical cancer SiHa cells were subjected to ALA and red light irradiation, and we then measured the ALA-PDT's effects on cell functions using various assays. The potential interaction between miR-152-3p and JAK1 was explored through bioinformatics analyses and validated by dual-luciferase reporter assays. Post-transfection with miR-152-3p and JAK1 vectors, cellular functions were re-evaluated. The efficacy of ALA-PDT in tumor suppression was further investigated through tumor transplantation experiment in vivo., Results: ALA-PDT markedly suppressed SiHa cell viability, invasion and migration, impacting critical markers of proliferation, apoptosis, and epithelial-mesenchymal transition(EMT). And these effects were echoed by the inhibition of miR-152-3p. JAK1 was identified as a direct target of miR-152-3p, and ALA-PDT was found to regulate the expression levels of miR-152-3p, consequently influencing the JAK1/STAT1 signaling pathway. Augmentation of miR-152-3p expression and inhibition of the JAK1/STAT1 pathway mitigated the anti-cancer effects of ALA-PDT, whereas JAK1 overexpression diminished these effects. In vivo analyses demonstrated that ALA-PDT suppressed tumor growth and modulated the miR-152-3p/JAK1/STAT1 pathway expression., Conclusions: ALA-PDT inhibits the viability, invasion, and migration of cervical cancer SiHa cells by modulating the miR-152-3p/JAK1/STAT1 axis, offering a promising therapeutic avenue for combating invasive cervical cancer., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest. No conflicting relationship exists for any author., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: As a rare subcutaneous infection, protothecosis is easily misdiagnosed. Similar to other subcutaneous infection, there is no unified standard for treatment, for cases not suitable for surgery, clinicians often use antifungal drugs based on their experience, and the course of treatment varies from several months to several years. Based on the fact that there are few relevant materials and researches on photodynamic therapy (PDT), we conducted a study based on a clinical case that used oral itraconazole combined with 5-aminolevylinic acid photodynamic therapy (ALA-PDT) to treat a patient with cutaneous protothecosis caused by Prototheca wicherhamii., Methods: Different concentrations of ALA and different light doses were used to investigate the effects of ALA-PDT on the growth inhibition of P. wickerhamii in vitro with Colony-counting Methods. And we used transmission electron microscopy (TEM) to visualize the structural changes and the effects of ALA-PDT treating on cellular structures of the P. wickerhamii. Futher, we performed the susceptibility test of P. wickerhamii to itraconazole before and after ALA-PDT in vitro., Results: We have successfully treated a patient with cutaneous protothecosis caused by P. wickerhamii by using combination therapy in a total of 9-week course of treatment. In vitro, ALA-PDT can inhibit the growth of P. wickerhamii when the ALA concentration was 5 mg/mL (P < 0.01), and this effect became stronger as the concentration of ALA or light dose is increased. Using TEM, we confirmed that ALA-PDT can disrupt the cell wall structure and partition structure of P. wickerhamii, which may contribute to its inhibitory effect. Further studies showed that the MIC of itraconazole for P. wickerhamii was decreased after ALA-PDT., Conclusions: ALA-PDT combined with oral itraconazole can be used to treat cutaneous protothecosis. Accordingly, ALA-PDT can destroy the cell wall and partition structure of P. wickerhamii leading to an inhibitory effect on it in vitro, and the effect is enhanced with the increase of ALA concentration and light dose. Also, the sensitivity of P. wickerhamii to itraconazole is observed increased after ALA-PDT. So our study provides a theoretical basis for the promising treatment against cutaneus protothecosis., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: 5-aminolevulinic acid (5-ALA) is a precursor of the photosensitizer Protoporphyrin IX (PpIX) and photodynamic therapy (PDT) with 5-ALA has been used in clinical practice. However, tumor cellular hypoxia severely affects the efficiency of photodynamic therapy. In this study, photodynamic therapy was combined with tirapazamine to investigate the effects of the combined intervention and the related mechanisms it may involve., Methods: Colony formation assays were used to demonstrate cell proliferation. Transwell assays were performed to observe the effect on cell invasion and metastasis after the corresponding intervention. DCFH-DA probe was used to detect the reactive oxygen species content. Flow cytometry was used to detect the effects of the interventions on apoptosis and cell cycle. The relevant pathways that may be involved are explored by examining the expression levels of the relevant proteins and genes., Results: Colony formation assays indicated that the combined intervention inhibited cell proliferation. Transwell assays demonstrated that PDT combined with TPZ effectively inhibited tumor cell invasion and metastasis. In addition, fluorescence intensity generated by DCFH-DA oxidation was detected indicating that the combined intervention increased the formation of reactive oxygen species. Flow cytometry clearly showed that the combination of PDT and TPZ further increased apoptosis and cell cycle arrest. The results of western blotting and qRT-PCR experiments confirmed that the combination therapy inhibited HIF-1α/VEGF axis and the PI3K/Akt/mTOR pathway activation., Conclusion: 5-ALA-PDT combined with TPZ can inhibit cell proliferation, increase apoptosis, and inhibit the PI3K/Akt/mTOR pathway, thus inhibiting tumor growth and metastasis and improving anti-cancer effects., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Photodynamic therapy (PDT) has been utilized as a promising alternative cancer treatment due to its minimum invasiveness over the years. Exogenous 5-aminolevulinic acid (ALA) triggers protoporphyrin IX (PpIX) accumulation, which happens in cancer cells. However, certain types of cancer exhibit reduced effectiveness in the PpIX accumulation mechanism. This study aimed to determine the effect of ALA-PDT combination with hemin on gastric carcinoma TMK-1 cells., Methods: This study utilized TMK-1 gastric cancer cell line to evaluate PpIX, ROS, and Fe 2+ accumulation following the administration of ALA, hemin, and a combination of ALA and hemin PDT. We also evaluate the mRNA expressions related to iron homeostasis and treatment impacts on cell viability., Results: The co-addition of ALA and hemin PDT for 4 h of treatment resulted in a significant decrease in cell viability by up to 18 %. While ALA-PDT enhanced PpIX metabolism, the addition of hemin influenced both the production of reactive oxygen species (ROS) and cellular iron homeostasis by inducing Fe 2+ accumulation and affecting mRNA levels of IRP, Tfr1, Ferritin, NFS1, and SDHB., Conclusion: These findings suggest that the addition of ALA and hemin enhances phototoxicity in TMK-1 cells. The combination of ALA and hemin with PDT induces cell death, evidenced by increased cytotoxicity properties such as PpIX and ROS, along with significant changes in TMK-1 gastric cancer iron homeostasis. Therefore, the combination of ALA and hemin could be one of the alternatives in photodynamic therapy for cancer in the future., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Acne vulgaris is a species-specific human disease. To date, there has been no established human sebocyte cell line of Asian origin. Our previous study has demonstrated the efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of acne vulgaris, primarily attributed to its cytotoxic properties; however, its regulatory mechanism remains largely unknown., Objectives: To establish an immortalized human sebocyte cell line derived from Chinese population and investigate the underlying mechanism of ALA-PDT., Methods: Human primary sebocytes were transfected with the human tert gene (h‑tert). The biological characteristics, including cell proliferation, cell markers, and sebum secretion function, were compared between primary sebocytes and the immortalized sebocytes (XL-i-20). Stimulations such as ALA-PDT, were applied respectively to both primary sebocytes and XL-i-20 cells to assess changes in their cellular functions. The transcriptome differences between primary sebocytes and XL-i-20 sebocytes were investigated using RNA-seq analysis. The XL-i-20 cell line was used to establish a sebaceous gland (SG) organoid culture, serving as a representative model of SG for the investigation of ALA-PDT., Results: The h‑tert immortalized sebocyte cell line exhibited the ability to be consecutively cultured for more than fifty passages. Both primary and immortalized cells expressed sebocyte markers such as epithelial membrane antigens (EMA, or MUC-1), Cytokeratin 7 (CK7) and adipose differentiation-related protein associated antigens (ADRP), and maintained sebum secretion function. The proliferative capacity of XL-i-20 was found to be significantly higher than that of primary sebocytes. The responses of XL-i-20 to ALA-PDT were indistinguishable from those elicited by primary sebocytes. Cell viability and sebum secretion were decreased after ALA-PDT in both two cell lines, and lipid-related proteins (SREBP-1/PPARγ) were down-regulated. The transcriptome data consistently demonstrated upregulation of genes related to inflammatory responses and downregulation of genes involved in lipid metabolism in both cell types following PDT. The analysis of common differential genes of primary sebocytes and XL-i-20 sebocytes post ALA-PDT showed that TNF signaling pathways, MAPK signaling pathways and JAK-STAT signaling pathways were activated. The SG organoids were spherical, which expressed markers of FANS and PLET1. Ki-67 was down-regulated after ALA-PDT., Conclusions: We have developed an h‑tert immortalized sebocyte cell line from an Asian population. The cell line, XL-i-20, maintains the essential characteristics of its parent primary sebocytes. Moreover, XL-i-20 sebocyte exhibited a significant respond to ALA-PDT, demonstrating comparable phenotypic and molecular changes to primary sebocytes. Therefore, XL-i-20 and its derived SG organoid serve as appropriate in vitro models for investigating the efficacy and mechanisms of ALA-PDT in SG-related diseases., (Copyright © 2024. Published by Elsevier B.V.)

Background: Actinic keratosis (AK) is a precancerous lesion that occurs in areas that are chronically exposed to sunlight and has the potential to develop into invasive cutaneous squamous cell carcinoma (cSCC). We investigated the efficacy of 20 % 5-aminolevulinic acid-photodynamic therapy (ALA-PDT) with LED red light for the treatment of AK in Chinese patients by examining changes in dermoscopic features, histopathology and fluorescence after treatment., Methods: Twenty-eight patients with fourty-six AK lesions from March 2022 to September 2023 were treated with 20 % ALA, and 3 h later, they were irradiated with LED red light (80-100 mW/cm 2 ) for 20 min. A session of 20 % ALA-PDT was performed once a week for three consecutive weeks, and the dermoscopic, histopathological, fluorescent and photoaging outcomes were measured one week after the treatment., Results: One week after ALA-PDT, complete remission (CR) was reached in 53.6 % of patients. The CR of Grade I AK lesions was 100 %, that of Grade II lesions was 71.4 %, and that of Grade III lesions was 38.1 %. There was a significant improvement in the dermoscopic features, epidermal thickness and fluorescence of the AK lesions. The presence of red fluorescence decreased, and there was an association between CR and post-PDT fluorescence intensity. ALA-PDT also exhibited efficacy in treating photoaging, including fine lines, sallowness, mottled pigmentation, erythema, and telangiectasias, and improved the global score for photoaging. There were no serious adverse effects during or after ALA-PDT, and 82.1 % of the patients were satisfied with the treatment., Conclusion: AK lesions can be safely and effectively treated with 20 % ALA-PDT with LED red light, which also alleviates photoaging in Chinese patients, including those with multiple AKs. This study highlights the possibility that fluorescence could be used to diagnose AK with peripheral field cancerization and evaluate the efficacy of ALA-PDT., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

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., Competing Interests: Declaration of competing interest None, (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) is an effective treatment for pilosebaceous inflammatory diseases, such as acne vulgaris. In this study, we explored ALA-PDT's mechanisms against acne in vitro., Methods: We treated human SZ95 sebocytes with ALA (0.2 mM) and subjected them to varied PDT doses (0, 5, 10, 20 J/cm²) over 12 h. We assessed cell viability post-treatment using the Annexin V FITC/PI apoptosis kit. ROS accumulation in the sebocytes was detected with a DCFDA probe. We quantified NLRP3 and caspase-1 mRNA via quantitative PCR and determined IL-1β release following ALA-PDT by ELISA. Western blotting helped identify the levels of proteins associated with pyroptosis (NLRP3, caspase-1, and IL-1β). To elucidate the mechanisms, we re-evaluated these parameters after administering various concentrations of NAC antioxidants (0, 0.4, 2, 10 mM) and the caspase inhibitor Z-VAD-FMK (0, 5, 10, 20 μM)., Results: Increasing PDT dose inversely affected SZ95 sebocyte survival, with a corresponding rise in ROS and pyroptosis-related proteins (NLRP3, caspase-1, and IL-1β). Furthermore, NAC and Z-VAD-FMK modulated the expression and secretion of these molecules in a dose-responsive manner., Conclusion: Our findings suggest ALA-PDT's potential mechanism of action on sebaceous glands could involve ROS induction, leading to NLRP3 inflammasome assembly, thereby heightening caspase-1 activation and IL-1β secretion. This cascade may amplify the local inflammatory response to break chronic inflammation in acne vulgaris treatment., (Copyright © 2024. Published by Elsevier B.V.)

Significance: Photodynamic therapy (PDT) can be targeted toward different subcellular localizations, and it is proposed that different subcellular targets vary in their sensitivity to photobiological damage. Since singlet oxygen ( 1 O 2 ) has a very short lifetime with a limited diffusion length in cellular environments, measurement of cumulative 1 O 2 luminescence is the most direct approach to compare the PDT sensitivity of mitochondria and plasma membrane., Approach: PDT-generated near-infrared 1 O 2 luminescence at 1270 nm was measured together with cell viability for 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) and exogenous PpIX, at different incubation times. Confocal fluorescence microscopy indicated that ALA-induced PpIX (2 h) localized in the mitochondria, whereas exogenous PpIX (1 h) mainly localized to the plasma membrane. Cell viability was determined at several time points during PDT treatments using colony-forming assays, and the surviving fraction correlated well with cumulative 1 O 2 luminescence counts from PpIX in mitochondria and plasmas membrane, respectively., Results: The mitochondria are more sensitive than the plasma membrane by a factor of 1.7., Conclusions: Direct 1 O 2 luminescence dosimetry's potential value for comparing the PDT sensitivity of different subcellular organelles was demonstrated. This could be useful for developing subcellular targeted novel photosensitizers to enhance PDT efficiency., Competing Interests: Declaration of competing interest The authors have declared that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background: Selective accumulation of photosensitizers into cancerous cells is one of the most important factors affecting photodynamic therapy (PDT) efficacy. 5-aminolevulinic acid (5-ALA) is the precursor of a strong photosensitizer, protoporphyrin-IX; but it has poor permeability into the cells. Folate receptors are overexpressed on the surface of many tumor cells. In the present study, folic acid (FA) and 5-ALA conjugated bismuth oxide nanoparticles were synthesized; and used in PDT, radiotherapy (RT), and concurrent PDT & RT against nasopharyngeal carcinoma (KB cell line)., Methods: The KB cells were incubated with the synthesized nanoparticles (NPs) for 2 h; then illuminated using a custom-made LED lamp at the light dose of 26 J/cm 2 . Irradiation of the cells was carried out using X-ray 6 MV (2 Gy); and synergistic effect of the simultaneous RT and PDT treatments was evaluated using fractional product values. Efficacy of the treatments was determined using MTT and Caspase-3 enzyme activity assays., Results: Targeting of folic acid receptors enables the selective endocytosis of the conjugated NPs. RT results in the presence of Bi 2 O 3 NPs showed a significant radiosensitizer potential of these NPs. Fractional product values of 1.49±0.05, 1.36±0.06, and 1.05±0.06 obtained in the presence of FA-5-ALA conjugated NPs, 5-ALA conjugated NPs, and in the absence of the NPs, respectively. Therefore, simultaneous RT and PDT in the presence of these conjugated NPs is superior to RT in the presence of the NPs., Conclusion: Simultaneous PDT and RT in the presence of FA-5-ALA conjugated bismuth oxide NPs can be introduced as a promising therapeutic approach in controlling KB cancer cells., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Objective: Herein we describe initial results in a porcine model of a fully implantable device designed to allow closed, repetitive photodynamic treatment of glioblastoma (GBM)., Methods: This implant, Globus Lucidus, is a transparent quartz glass sphere with light-emitting diodes releasing wavelengths of 630 nm (19.5 mW/cm 2 ), 405 nm (5.0 mW/cm 2 ) or 275 nm (0.9 mW/cm 2 ). 5-aminolevulinic acid was the photosensitizing prodrug chosen for use with Globus Lucidus, hence the implants illuminated at 630 nm or 405 nm. An additional 275 nm wavelength-emittance was included to explore the effects of photochemical therapy (PCT) by ultraviolet (UV) light. Twenty healthy domestic pigs underwent right-frontal craniotomies. The Globus Lucidus device was inserted into a surgically created right-frontal lobe cavity. After postoperative recovery, irradiation for up to 30 min daily for up to 14 d, or continuous irradiation for up to 14.6 h was conducted., Results: Surgery, implants, and repeated irradiations using the different wavelengths were generally well tolerated. Social behavior, wound healing, body weight, and temperature remained unaffected. Histopathological analyses revealed consistent leukocyte infiltration around the intracerebral implant sites with no significant differences between experimental and control groups., Conclusion: This Globus Lucidus porcine study prepares the groundwork for adjuvant, long-term, repeated PDT of the GBM infiltration zone. This is the first report of a fully implantable PDT/PCT device for the potential treatment of GBM. A preclinical effectivity study of Globus Lucidus PDT/PCT is warranted and in advanced stages of planning., Competing Interests: Declaration of competing interest The funders had no role in the study design, analyses, data interpretation, writing, or decision to publish., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Photodynamic Therapy (PDT) is a clinically approved cancer treatment. Sex hormones, the key drivers for the development of female hormonal dependent cancers, might affect cancer treatment. There are seldom studies to evaluate the effect of sex hormones mimicked the menstrual cycle on the PDT mediated by prodrug 5-aminolevulinic acid (ALA) and its ester derivatives to the hormonal dependent cancers., Aims: To evaluate the efficacy of sex hormones on Hexyl-ALA-PDT in hormonal dependent cancers and the effect of the sex hormones on heme biosynthetic pathway., Methods: Cell culture system that mimicked the fluctuation of sex hormones 17β-estradiol (E2) and progesterone (PG) in the menstrual cycle was developed. Two pairs of hormonal-independent and hormonal dependent uterine sarcoma and breast cancer cell lines were used as cell models. Hexyl-ALA induced PpIX production and intracellular localization were examined. Key enzymes for PpIX synthesis were analysed. Hexyl-ALA-PDT mediated phototoxicity was evaluated., Results: The PpIX generation was increased in the hormonal-dependent cells (28-50 %) when cultured in the hormonal microenvironment with long incubation of Hexyl-ALA for 15 and 24 h compared to that cultured without hormones; whereas only slight difference in PpIX generation in their hormonal-independent counterpart. The PpIX generation was in a time-dependent manner. The CPOX, PPOX and FECH expressions were significantly enhanced by Hexyl-ALA-PDT in uterine sarcoma cells in hormonal microenvironment. Hexyl-ALA-PDT triggered significant increase of PPOX expression in breast cancer cells in hormonal microenvironment. The Hexyl-ALA-PDT phototoxicity was enhanced by 18-40 % in cells cultured in the hormonal system in a dose-dependent manner., Conclusion: The PpIX generation and the efficacy of Hexyl-ALA-PDT in both uterine sarcoma and breast cancer cells was significantly enhanced by the sex hormones via cultured in the hormonal microenvironment., (Copyright © 2024. Published by Elsevier B.V.)

Improved treatment outcomes for non-melanoma skin cancers can be achieved if Vitamin D (Vit D) is used as a neoadjuvant prior to photodynamic therapy (PDT). However, the mechanisms for this effect are unclear. Vit D elevates protoporphyrin (PpIX) levels within tumor cells, but also exerts immune-modulatory effects. Here, two murine models, UVB-induced actinic keratoses (AK) and human squamous cell carcinoma (A431) xenografts, were used to analyze the time course of local and systemic immune responses after PDT ± Vit D. Fluorescence immunohistochemistry of tissues and flow analysis (FACS) of blood were employed. In tissue, damage-associated molecular patterns (DAMPs) were increased, and infiltration of neutrophils (Ly6G+), macrophages (F4/80+), and dendritic cells (CD11c+) were observed. In most cases, Vit D alone or PDT alone increased cell recruitment, but Vit D + PDT showed even greater recruitment effects. Similarly for T cells, increased infiltration of total (CD3+), cytotoxic (CD8+) and regulatory (FoxP3+) T-cells was observed after Vit D or PDT, but the increase was even greater with the combination. FACS analysis revealed a variety of interesting changes in circulating immune cell levels. In particular, neutrophils decreased in the blood after Vit D, consistent with migration of neutrophils into AK lesions. Levels of cells expressing the PD-1+ checkpoint receptor were reduced in AKs following Vit D, potentially counteracting PD-1+ elevations seen after PDT alone. In summary, Vit D and ALA-PDT, two treatments with individual immunogenic effects, may be advantageous in combination to improve treatment efficacy and management of AK in the dermatology clinic., Competing Interests: Declarations of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Background: Numerous studies have shown that photodynamic therapy (PDT) has a therapeutic effect on mammary tumor cells, with 5-aminolevulinic acid (5-ALA-HCL) being a commonly used photosensitizer for PDT. Feline mammary tumors (FMTs) are relatively common. However, the cytotoxic and antitumor effects of 5-ALA-PDT on FMTs have not been clarified. To this end, we evaluated the therapeutic effect of 5-ALA-PDT on FMTs through in vitro experiments using an FMT FKR cell line established for this study., Methods: We performed 5-ALA-PDT in 2D-cultured FKR-A (adherent cells) and 3D-cultured FKR-S (spheroid cells) cells and performed a series of studies to evaluate the cell viability and determine the protoporphyrin IX (PpIX) content in the cells as well as the expression levels of mRNAs associated with PpIX production and release. An in vivo study was performed to assess the effectiveness of 5-ALA-PDT., Results: There was a significant difference in the concentration of PpIX in FMT cells under different incubation culture modes (2D versus 3D culture). The concentration of PpIX in FMT cells was correlated with the differences in cell culture (2D and 3D) as well as the expression levels of genes such as PEPT1, PEPT2, FECH, and HO-1., Conclusions: In the in vitro study, 5-ALA-PDT had a stronger inhibitory effect on 3D-cultured FKR-S cells, which resemble the internal environment of organisms more closely. We also observed a significant inhibitory effect of 5-ALA-PDT on FMT cells in vivo. To our knowledge, this is the first study on 5-ALA-PDT for FMTs under both 2D and 3D conditions., Competing Interests: Declaration of competing interest Urara Ota, Hideo Imazato, Kiwamu Takahashi, and Masahiro Ishizuka are employees of SBI Pharmaceuticals Co., Ltd. Siyao Lin and Tomohiro Osaki declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Hypertrophic scars, an abnormal wound-healing response to burn injuries, are characterized by massive fibroblast proliferation and excessive deposition of extracellular matrix and collagen. 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is a promising therapy for hypertrophic scar, details of the mechanisms remain to be elucidated. In this study, we aimed to investigate the molecular mechanisms involved in ALA-PDT against hypertrophic scar fibroblasts., Methods: The morphologies of hypertrophic scar fibroblasts (HSFs) treated with ALA-PDT were observed under a light microscopy. The viability of HSFs was detected using the CCK-8 assay. HSFs-populated collagen gel contraction assays were conducted to examine the fibroblast contractility and the cytotoxicity of HSFs in 3D collagen tissues were observed using confocal microscopy. The effect of ALA-PDT on TGF-β1/Smad2/3/4 signaling pathway activation and effector gene expression were verified by immunoprecipitation, western blot and real-time quantitative PCR analysis., Results: We observed significant changes in cell morphology after ALA-PDT treatment of HSFs. As ALA concentration and light dose increased, the viability of HSFs significantly decreased. ALA-PDT can significantly alleviate the contractile capacity and promote the death of HSFs induced by TGF-β1 treatment in a three-dimensional collagen culture model. TGF-β1 treatment of HSFs can significantly induce phosphorylation of Smad2/3 (p-Smad2/3) in whole cells, as well as p-Smad2/3 and Smad4 proteins into the nucleus and increase the mRNA levels of collagen 1/3 and α-SMA. ALA-PDT hampers the TGF-β1-Smad2/3/4 signaling pathway activation by inducing K48-linked ubiquitination and degradation of Smad4., Conclusions: Our results provide evidence that ALA-PDT can inhibit fibroblast contraction and promote cell death by inhibiting the activation of the TGF-β1 signaling pathway that mediates hypertrophic scar formation, which may be the basis for the efficacy of ALA-PDT in the treatment of hypertrophic scars., Competing Interests: Declaration of Competing Interest The authors report no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background: The treatment of deep-invasive cutaneous squamous cell carcinoma (cSCC) is difficult. Sonodynamic therapy (SDT) has showed advantages in large penetration depth, small trauma, good repeatability, high targeting selectivity and effective protection for intact structure and function of tissues and organs., Objective: To study the efficacy and safety of 5-aminolevulinic acid SDT (ALA-SDT) in the treatment of cSCC., Methods: The absorption and transformation of ALA after co-incubation with cSCC were detected by UV-Vis and fluorescence absorption. The production of reactive oxygen species (ROS) when protoporphyrin IX (PpIX) excited with ultrasound was detected by ROS detection probe. Cytotoxicity of ALA-SDT to cSCC was detected with cytotoxicity indicators. The tumor volume changes and tumor weight of mice after ALA-SDT were detected. The effects of ALA-SDT on the growth of mice were evaluated through the changes in body weight of mice. Biosafety of treatment was further evaluated by histopathology to determine whether the tissues and organs of mice were affected after ALA-SDT., Results: ALA can be absorbed and converted into PpIX when incubated with cSCC cells and produces ROS with ultrasound irradiation. ALA-SDT showed a significant cytotoxicity on cSCC cells. With one session of ALA-SDT in vivo, tumor growth was slowed but not stopped and would proceed once treatment was ended. ALA-SDT had no significant effect on body weight changes and major tissues and organs of the mice., Conclusion: ALA-SDT could safely and reduce cSCC cells growth both in vitro and in vivo., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Aminolevulinic acid-photodynamic therapy (ALA-PDT) is gaining attention as a potential method for treating select cancers due to its high specificity and low side effect feature. ALA enters cancer cells and accumulate as protoporphyrin IX (PpIX), which will then trigger phototoxicity following light irradiation. However, it is reported that some cancer cells have reduced efficacy of ALA-PDT due to high expression of ABCG2, a transporter involved in the PpIX efflux. In this study, we evaluated the effect of mangostin, a natural compound containing anti-tumor property, on the efficacy of ALA-PDT against cancer and the mechanism involved., Methods: We utilized TMK1 gastric cancer cell line, which has high ABCG2 expression, to evaluate the PpIX accumulation and phototoxicity exerted by ALA and mangostin co-addition., Results: We found that co-addition of ALA and mangostin significantly increase the phototoxicity and PpIX accumulation in TMK1 cells. We also investigated the effect of mangostin on porphyrin-heme pathway enzymes and ABCG2 and found that the addition of mangostin reduce the activity of ABCG2, reducing PpIX efflux., Conclusion: These findings suggest that mangostin enhances the efficacy of ALA-PDT in cancer through inhibition of ABCG2 activity., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Keloids display many cancerous properties, including uncontrolled and invasive growth, high rates of recurrence as well as similar bioenergetics. 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) is an effective treatment that performs cytotoxic effects by producing reactive oxygen species (ROS), which is linked to lipid peroxidation and ferroptosis. Herein, we explored underlying mechanisms of 5-ALA-PDT against keloids. We identified that 5-ALA-PDT led to elevated levels of ROS and lipid peroxidation in keloid fibroblasts, accompanied by downregulation of xCT and GPX4, which are associated with anti-oxidation effects and ferroptosis inhibition. These results may indicate that 5-ALA-PDT treatment increases ROS while inhibiting xCT and GPX4, thus promoting lipid peroxidation to induce ferroptosis in keloid fibroblasts., Competing Interests: Declaration of Competing Interest The authors report no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

Aminolevulinic acid-photodynamic diagnosis (ALA-PDD) is a promising alternative method to detect cancer cells because of its high specificity and low rate of side effects. Exogenous ALA is administered and accumulates as protoporphyrin IX (PpIX) in cancer cells, which then emit red fluorescence following light irradiation to enable surgeons to accurately identify and remove cancerous tissue. Recent reports suggested that PpIX failed to accumulate in some patients who underwent ALA-PDD. We hypothesized that cell senescence, which is a relatively inactive state, affects porphyrin accumulation in bladder cancer cells. In this study, we evaluated the relationship between cell senescence and porphyrin accumulation in affecting the efficacy of ALA-PDD. First, we utilized three bladder cancer cell lines to evaluate senescence-related indicators and establish a cell senescence model. Then, we identified the differences in porphyrin production and the proteins involved in porphyrin accumulation between old and young cells. We found that compared with young cells, old cells possessed higher concentration of PpIX and had lower ABCG2 expression. The increase in PpIX levels following ABCG2 inhibition is three times higher in old cells than in young cells, suggesting that cell senescence was closely related with porphyrin accumulation in cancer. In conclusion, we found that the efficacy of ALA-PDD and porphyrin accumulation was relatively high in senescent cancer cells and that inhibition of ABCG2 could improve the efficacy of ALA-PDD in young bladder cancer cells., (Copyright © 2023. Published by Elsevier B.V.)

Background: Fibroblastic soft-tissue tumors share enzymatic anomalies that result in excessive intracellular conversion of 5-aminolevulinic acid (5-ALA) to protoporphyrin IX, a photosensitizer which induces cellular apoptosis upon exposure to visible red light at a wavelength of 635 nm. We hypothesized that red light illumination of the surgical bed remaining after resection of fibroblastic tumors will result in destruction of microscopic tumor residua and may decrease the likelihood of local tumor recurrence., Methods: Twenty-four patients with desmoid tumors, solitary fibrous tumors (SFT), and dermatofibrosarcoma protuberans (DFSP) received oral 5-ALA prior to resection of their tumors. Following tumor resection, the exposed surgical bed was illuminated with red light at a wave length of 635 nm at a dose of 150 J/cm 2 for 33 min., Results: Treatment with 5-ALA was associated with minor side effects that included nausea and transient elevation of transaminases. Local tumor recurrence was detected in 1 of the 10 patients with desmoid tumors who had not undergone any previous surgery, none in the 6 patients who had SFT and 1 of the 5 patients who had DFSP., Conclusions: 5-ALA photodynamic therapy of fibroblastic soft-tissue tumors may result in decreased likelihood of local tumor recurrence. It is associated with minimal side effects and should be considered as adjuvant to tumor resection in these cases., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Cancer cells with stem cell-like features are generally more resistant to chemotherapy and radiotherapy than differentiated tumor cells. Thus, these cells tend to increase the propensity for tumor recurrence and metastasis. This study investigated the efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) in destructing glioma stem cells (GSCs), including the mesenchymal subtype (MES-GSCs) demonstrated to have the lowest radio- and chemosensitivity., Methods: Five high-grade glioma (HGG) GSC lines and derived differentiated glioma cell (DGC) lines were examined for protoporphyrin-IX (PpIX) expression using fluorescence-activated cell sorting (FACS) and then assessed for ALA-PDT sensitivity using cell viability assays. MES-GSCs surviving ALA-PDT were then isolated and evaluated for stem cell and mesenchymal marker expression levels (CD44, ALDH1A3, KLF4, nestin) by qRT-PCR. The ability of these surviving cells to form tumors was then examined using colony forming and by xenograft tumor assays in athymic mice. Finally, the relationship between PpIX expression level (high versus low) and ALA-PDT sensitivity was examined by FACS and colony forming assays., Results: ALA-PDT was effective against all GSC lines including MES-GSCs. MES-GSC lines exhibited higher PpIX expression than derived DGCs. Surviving MES-GSCs demonstrated lower stem cell marker expression and tumor forming potential than naive MES-GSCs. Higher PpIX production capacity by MES-GSCs was associated with greater colony forming ability, and ALA-PDT was more effective against MES-GSCs with greater PpIX accumulation., Conclusion: ALA-PDT may be clinically effective against HGG by targeting GSCs, including MES-GSCs., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

In vitro dose escalation experiments are one of the first gatekeepers in therapeutic evaluation and development. This also holds for evaluating novel photosensitizers (PS) and Photodynamic Therapy (PDT) co-therapies as needed to provide dose response guidelines before engaging in further pre-clinical studies. The dose needed to achieve 50% cell kill (LD 50 ) is a standard metric to report the potency of a therapeutic agents that is widely accepted for single-drug therapies. In reporting results of PDT experiments, which involve delivery of both drug and light, it is inherently more complicated to identify such a convenient dose response metric that actually captures the larger space of treatment parameters. In addition to ubiquitous sources of biological variability that apply broadly in biomedical research, PDT treatment efficacy is determined by multiple key parameters that may or may not have been documented, including PS concentration and light fluence, where the latter is itself a function of the spectral properties of the light source used (often not described), not to mention dose rate, fractionation and other parameters that potentially vary between individual studies. It is impossible to compare results between two study when, for example one reports LD 50 PS concentration without providing essential light dosimetry details. Motivated by this challenge in comparing outcomes and establishing reproducibility of in vitro PDT studies, we endeavored to perform a meta-analysis of the reporting of PDT results by converting, where possible, the disparately reported experimental details into a consistent metric that could be used to compare across studies. In this context we adopt here the number of photons absorbed by photosensitizers per unit volume to affect a 50% decline in cell survival as a standardized metric. By choosing this metric one can acknowledge the quantum-based generation of cytotoxins. While this metric does not cover every possible source of variability between any two studies, for a PS with known optical properties, this does encapsulate PS concentration as well as irradiance and spectral properties of light delivered. For the sake of focus we adopt this approach for study of reported results with two photosensitizers, Protoporphyrin IX, either synthesized in the cells by aminolevulinic acid or administered exogenously, and Chlorin e6. A literature search was performed to identify in vitro studies with these two photosensitizers and collect necessary information to calculate the absorbed photon LD 50 threshold for each study. Only approximately 1/10 of the manuscripts reporting on in vitro studies provide the minimum required information to calculate the threshold values. While the majority of the determined threshold values are within a factor of 10, the range of threshold values spanned close to 7 orders of magnitude for both photosensitizers. To contrast with single-agent therapies, a similar exercise was performed for chemotherapeutic drugs targeting cellular mitosis or tyrosine kinase inhibitors resulted in an LD 50 or IC 50 range of 1-2 orders of magnitude, with LD 50 or IC 50 values for a single cell line being within a factor of 5. This review underscores challenges in the reporting of in vitro PDT efficacy. In many cases it takes considerable effort to extract the necessary methodology information to make meaningful comparison between PDT studies. Only when results between studies can be compared is it possible to begin to assess reproducibility which, as shown here, can be a major issue. Hence, guidelines need to be developed and enforced through the peer review process for meaningful reporting of preclinical PDT results in order for the most promising sensitizers and co-therapies to be identified and translated into the clinic., Competing Interests: Declaration of Competing Interest The authors do not declare any conflict of interest with this study., (Copyright © 2022. Published by Elsevier B.V.)

Background: Mitochondrial dysfunctions are related to cancer development.. 5-aminolevulinic acid (ALA) is used for photodynamic therapy (PDT). In this PDT, protoporphyrin IX (PpIX), which is converted from ALA, can generate reactive oxygen species (ROS) that kill the cancer cell. ALA is also reported to promote cytochrome c oxidase (COX) activity, which can generate ROS itself. Therefore, this study focused on the effect of ALA during PDT. In addition, in the previous study, sodium ferrous citrate (SFC) is reported to increase COX activity. So, this study also aims to improve the COX activity by the addition of SFC that can promote ROS generation, which has a cytotoxic effect., Methods: In this study, we used ALA and SFC, then evaluated the effects of the treatment on the human gastric cancer cell line MKN45, including the induction of cell death., Results: This study showed that treatment with ALA and SFC increases intracellular heme and heme proteins. Moreover, COX activity was promoted, resulting in the production of intracellular reactive oxygen species (ROS), which eventually reduced the cell viability in human gastric cancer cell line MKN45., Conclusion: Our study can detect ROS generation with ALA and SFC. Furthermore, we found this generation of ROS has a cytotoxic effect. Therefore, this phenomenon contributes to the effect of PDT., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022. Published by Elsevier B.V.)

Background: Traditional treatments for human papillomavirus-related cutaneous diseases include 5-aminolevulinic acid photodynamic therapy, cryotherapy, microwave ablation, and surgical resection. These treatment methods involvevarious adverse reactions; therefore, it remains necessary to explore new treatment methods. Dihydroartemisinin shows cytotoxic effects against several malignancies by producing reactive oxygen species, and heme environments reportedly enhance its activity. However, the underlying mechanismsare still unclear. Therefore, we investigated the mechanism of dihydroartemisininin inhuman papillomavirus-infected cells., Methods: HeLa cells were treated with dihydroartemisinin, 5-aminolevulinic acid, and succinylacetone. The cell viability, apoptosis, mitochondrial membrane potential, and reactive oxygen species levels were investigated, and via western blotting analysis and polymerase chain reaction, dihydroartemisinin activity-related pathways were also determined., Results: Dihydroartemisinin inhibited HeLa cell proliferation and promoted cell apoptosis via the Bax/Bcl-2-Caspase pathway in a concentration-dependent manner. The specific cytotoxicity toward HeLa cells was enhanced by the addition of 5-aminolevulinic acid, a clinically used heme-synthesis precursor, owing to an increase in heme levels. Conversely, following the addition of succinylacetone, a heme synthesis blocker, heme levels decreased. Furthermore, dihydroartemisinin significantly increased reactive oxygen species levels as intracellular heme synthesis increased. Moreover, photodynamic therapy following dihydroartemisinin and 5-aminolevulinic acid treatment further enhanced the cytotoxic effect of dihydroartemisinin on high-risk human papillomavirus-infected cells., Conclusions: Dihydroartemisinin exerts acytotoxic effect on high-risk human papillomavirus-infected cells by modulating heme levels via the Bax/Bcl-2-Caspase pathway, and the dihydroartemisinin, 5-aminolevulinic acid, photodynamic therapy combination treatment significantly enhanced its cytotoxic effect on human papillomavirus-infected cells., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

Background: Antimicrobial photodynamic therapy (aPDT) using aminolaevulinic acid (ALA) is a promising alternative to antibiotic therapy. ALA administration induces protoporphyrin IX (PpIX) accumulation in bacteria, and light excitation of the accumulated PpIX generates singlet oxygen to bacterial toxicity. Several factors, including drug administration and light irradiation conditions, contribute to the antibiotic effect. Such multiple parameters should be determined moderately for effective aPDT in clinical practice., Methods: A mathematical model to predict bacterial dynamics in ALA-aPDT following clinical conditions was constructed. Applying a pharmacokineticspharmacodynamics (PK-PD) approach, which is widely used in antimicrobial drug evaluation, viable bacteria count by defining the bactericidal rate as the concentration of singlet oxygen produced when PpIX in bacteria is irradiated by light., Results: The in vitro experimental results of ALA-aPDT for Pseudomonas aeruginosa demonstrated the PK-PD model validity. The killing rate has an upper limit, and the lower power density for a long irradiation time can suppress the viable bacteria number when the light dosages are the same., Conclusions: This study proposed a model of bacterial viability change in ALA-aPDT based on the PK-PD model and confirmed, by in vitro experiments using PA, that the variation of bacterial viability with light-sensitive substance concentration and light irradiation power densities could be expressed. Further validation of the PK-PD model with other gram negative and gram positive strains will be needed., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Glioblastoma (GBM) is a high-grade, poor prognosis tumor that is resistant to standard treatment. The presence of a small number of glioma stem cells (GSCs) surviving in the harsh microenvironment is responsible for their refractoriness. This study aimed to investigate the effect of a hypoxic environment on the sensitivity of GSCs to photodynamic therapy with 5-aminolevulinic acid (ALA-PDT)., Materials and Methods: Six human GSC lines, Mesenchymal types HGG13, HGG30, HGG1123, and Proneural types HGG146, HGG157, HGG528, were divided into two groups: normoxia (O 2 21%)-cultured cells (Normoxia-GSCs), and hypoxia (O 2 5%)-cultured cells (Hypoxia-GSCs). To compare the effects of different oxygen partial pressures on photoporphyrin Ⅸ (PpⅨ) biosynthetic activity, PpⅨ biosynthetic enzyme and transporter expression levels were examined by qRT-PCR; the intracellular PpⅨ concentration was determined using flow cytometry. Additionally, the sensitivity of these two groups of cells to ALA-PDT was evaluated in vitro., Results: Hypoxia-GSCs showed higher mRNA levels of FECH (ferrochelatase), which is required for iron synthesis to convert PpⅨ to heme, compared with Normoxia-GSCs. Flow cytometry revealed that the accumulation of PpⅨ in Hypoxia-GSCs reduced upon incubation with ALA. However, Hypoxia-GSCs showed less reduction in sensitivity to ALA-PDT than Normoxia-GSCs., Conclusion: Hypoxia-GSCs had lower intracellular PpⅨ accumulation than Normoxia-GSCs due to increased gene expression of FECH, and that their sensitivity to ALA-PDT was reduced less, despite accumulating lower concentrations of PpⅨ. ALA-PDT is a potentially effective therapy for hypoxia-tolerant GSCs that exist in hypoxia at 5% oxygen concentration., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022. Published by Elsevier B.V.)

5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) is an effective therapy in treating inoperable cutaneous squamous cell carcinoma (cSCC) in China. However, its exact mechanism in treating cSCC is still unclear. Here, we analyzed expression profiles of lncRNAs and mRNAs of cSCC after ALA-PDT in a mouse model using Mouse Transcriptome Assay 1.0 chip. A total of 592 and 828 differentially expressed genes were identified in comparisons of ALA-PDT after 3 h vs. control, ALA-PDT after 6 h vs. control respectively. Regarding the lncRNAs analysis, a total of 185 and 410 differentially expressed lncRNAs were sought out. Bioinformatics analyses including Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway, pathway relation network, and gene set enrichment analysis revealed that the pathways of ALA-PDT in treating cSCC were mainly associated with immune regulation, NF-κB signaling pathway, TLR signaling pathway, PI3K-Akt signaling pathway, TNF signaling pathway, and MAPK signaling pathway, which was validated by western blot analysis. Furthermore, a lncRNA-mRNA co-expression network revealed 118 network pairs comprising 36 lncRNAs and 68 mRNAs. These findings provide a basis for investigations into the treatment mechanisms of ALA-PDT in treating cSCC., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Glioblastoma multiforme is a malignant neoplasia with a median survival of less than two years and without satisfactory therapeutic options. The so-called glioblastoma stem cells escape the established radio- and chemotherapies and lead to tumor recurrence in most cases. The alkaloid Shikonin with its various anti stem cell properties and the interstitial photodynamic therapy with 5-aminolevulinic acid seem to be promising new options in the therapy of glioblastoma. In this study, in vitro investigations were performed to observe the influence of Shikonin on viability, proliferation, induction of apoptosis and the capability of forming tumor spheres in U-87 MG and the primary glioblastoma cell line GB14. The combined effect with the chemotherapeutic temozolomide and photodynamic treatment on the mRNA expression of glioma specific stem cell markers and further examined intracellular protoporphyrin IX accumulation under Shikonin treatment was analyzed. Shikonin effectively inhibited the capability of forming tumor spheres and enhanced temozolomide effectiveness in the reduction of proliferation and in the induction of apoptosis. Additionally, Shikonin increased the mRNA expression of the tumor suppressing Neurofibromatosis type 1 (NF1) gene and showed modulating effects on intracellular protoporphyrin IX., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Photodynamic therapy (PDT) is clinically approved to treat neoplastic skin diseases such as precursors of cutaneous squamous cell carcinoma (cSCC). In PDT, 5-aminolevulinic acid (5-ALA) drives the selective formation of the endogenous photosensitizer protoporphyrin IX (PpIX). Although 5-ALA PDT is clinically highly effective, resistance might occur due to decreased accumulation of PpIX in certain tumors. Such resistance may be caused by any fundamental step of PpIX accumulation: 5-ALA uptake, PpIX synthesis and PpIX efflux., Methods: We investigated PpIX accumulation and photodynamically induced cell death in PDT refractory SCC-13, PDT susceptible A431, and normal human epidermal keratinocytes (NHEK). Expression of genes associated with cellular PpIX kinetics was investigated on mRNA and protein level. PpIX accumulation and cell death upon illumination were pharmacologically manipulated using drugs targeting 5-ALA uptake, PpIX synthesis or efflux., Results: The experiments indicate that taurine transporter (SLC6A6) is the major pathway for 5-ALA uptake in cSCC cells, while being less important in NHEK. Downregulation of PpIX synthesis enzymes in SCC-13 was counteracted by methotrexate (MTX) treatment, which restored PpIX formation and cell death. PpIX efflux inhibitors targeting ABC transporters led to significantly increased PpIX accumulation in SCC-13, thereby fully overcoming resistance., Conclusions: The results indicate a conserved threshold for PpIX accumulation with respect to PDT-resistance. Cells showed increased viability after PDT at PpIX concentrations below 1.5 nM. Selective uptake of 5-ALA via taurine transporter SLC6A6 in cutaneous tumor cells is novel but unrelated to resistance. MTX can partially abrogate resistance by PpIX synthesis enzyme induction, while efflux mechanisms via ABC transporters seem the main driving force and promising drug targets., Competing Interests: Declaration of Competing Interest HL previously held positions as chair of the department of animal physiology at Ruhr-University Bochum and as General Manager of Biofrontera Bioscience GmbH. BN holds a double position, as visiting scientist of the department of animal physiology at Ruhr-University Bochum and as employee of Biofrontera Biosciences GmbH, a company which developed and holds regulatory approval for an 5-ALA containing drug in the EU. NS, LK and AY declare no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

The efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) on invasive cutaneous squamous cell carcinoma (cSCC) remains to be improved due to the limited penetration of this treatment. Previous study showed that acitretin and ALA-PDT had synergistic effect on cSCC, but whether acitretin can enhance the cytotoxic effect of ALA-PDT on cSCC is unclear., Objective: To investigate whether acitretin can enhance the cytotoxic effect of ALA-PDT on SCL-1 cells, as well as the possible mechanism involved., Methods: Inverted microscopy, trypan blue exclusion assay, and flow cytometry were used to studied the morphology, viability and apoptosis of SCL-1 cells treated with acitretin, ALA-PDT and acitretin followed by ALA-PDT treatment, respectively. Confocal microscopy was applied to detect the ROS formation of SCL-1 cells treated with acitretin of four different concentrations. The ROS formation of SCL-I cells treated with acitretin of four different concentrations followed by ALA-PDT treatment was detected using confocal microscopy and flow cytometry., Results: SCL-1 cells exhibited a significant morphological alteration when treated with acitretin followed by ALA-PDT. The combination of acitretin and ALA-PDT induced a higher cell death rate and apoptosis than that with acitretin or ALA-PDT treatment alone. ROS could be induced when incubated with acitretin at a concentration of 6.4 × 10 -4 mg /mL or above. However, a higher level of ROS formation was observed when SCL-1 cells were treated with acitretin followed by ALA-PDT than that with ALA-PDT or acitretin alone., Conclusion: Acitretin can enhance the cytotoxic effect of ALA-PDT on SCL-1 cells, possibly via the ROS pathway., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Background: Although 5-aminolevulinic acid photodynamic therapy (ALA-PDT) has been extensively used to treat various skin diseases, application for the treatment of cutaneous infection caused by Mycobacterium marinum (M. marinum), especially drug-resistant M. marinum, is unclear., Objectives: We evaluated the efficacy of ALA-PDT on M. marinum in a mouse infection model and tested its killing effect on M. marinum in vitro. We also investigated the clinical effect of ALA-PDT on cutaneous granuloma caused by drug-resistant M. marinum., Materials and Methods: A total of 9 M. marinum strains isolated from patients were tested for anti-mycobacterial susceptibility. The effects of ALA-PDT on M. marinum in vitro and in mice model were investigated. Therapeutic efficacy was further assessed in two patients with cutaneous granuloma caused by drug- resistant M. marinum., Results: We demonstrated that ALA-PDT directly killed M. marinum in vitro. The cutaneous lesions on mouse paws caused by M. marinum were fully recovered 4 weeks after the ALA-PDT treatment. ALA-PDT was also effective in two patients with cutaneous infection caused by drug-resistant M. marinum. The level of intracellular ROS in M. marinum treated with ALA-PDT was significantly higher than that of M. marinum alone., Conclusions: The results suggest that ALA-PDT is effective in treating M. marinum cutaneous infections by releasing more reactive oxygen species to kill M. marinum directly, and these effects are independent of systemic immune responses. The data highlights that ALA-PDT is a promising therapeutic choice for treatment of M. marinum cutaneous infections, especially drug-resistant M. marinum infections., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objectives: Intraoperative visualization of gliomas with 5-aminolevulinic acid (5-ALA) induced fluorescence constitutes a powerful technique. While visible fluorescence is typically observed in high-grade gliomas, fluorescence is considerably less common in lower-grade gliomas (LGGs) WHO grade II&III. Whereas the exact mechanisms determining fluorescence in LGGs are not fully understood, metabolization of non-fluorescent 5-ALA to fluorescent Protoporphyrin IX by specific heme biosynthesis enzymes/transporters has been identified as relevant mechanism influencing fluorescence behavior. Furthermore, recent in-vitro studies have suggested preoperative treatment with corticosteroids and anti-epileptic drugs (AED) as potential factors influencing 5-ALA induced fluorescence., Methods: The goal of this study was thus to investigate the effect of preoperative corticosteroid/AED treatment on heme biosynthesis mRNA expression in a clinically relevant patient population. For this purpose, we analyzed the mRNA expression levels of specific heme biosynthesis factors including ALAD, HMBS, UROS, UROD, CPOX, PPOX, FECH, ABCB6, ACG2, SLC15A1 and SLC15A2, ABCB1, ABCB10 in a cohort of LGGs from "The Cancer Genome Atlas"., Results: Altogether, 403 patients with available data on preoperative corticosteroid/AED treatment and heme biosynthesis mRNA expression were identified. Regarding corticosteroid treatment, no significant differences in expression of any of the 11 investigated heme biosynthesis factors were found. In contrast, a marginal yet statistically significant increase in SLC15A1 levels and decrease in ABCB6 levels were observed in patients with preoperative AED treatment., Conclusion: While no significant differences in heme biosynthesis mRNA expression were observed according to preoperative corticosteroid treatment, changes in SLC15A1 as well as ABCB6 expression were detected in patients treated with AED. However, since these alterations were minor and have opposing effects on 5-ALA metabolization, our findings do not support a distinct effect of AED and corticosteroid treatment on heme biosynthesis regulation in LGGs., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Aim: The present study was intended to evaluate the antimicrobial effect of PDT, H 2 O 2, and MI on the contact angle, strain-in-compression, and tear strength of siloxane impression material formerly colonized with E. coli, S.aureus and S.mutans., Material and Methods: One hundred and twenty disk-shaped specimens (diameter 10 mm and thickness 2 mm) were prepared by polyvinylsiloxane impression material and inoculated by the American Type Culture Collection (ATCC) of E.coli, S.mutans, and S.aureus in an in-vitro situation. The specimens were broadly divided into six groups then exposed to the various disinfection approaches for 3 min per each group: group 1: Control (no treatment), group 2:PDT 5-ALA, group 3: H 2 O 2 , group 4: MI, group 5: H 2 O 2  + MI, group 6: PDT + MI. After disinfection, assessment of mechanical properties (contact angle, strain-in-compression, and tear strength) of impression materials were instigated. Statistical analysis was executed for CFU/mL (log10) for exposed E. coli, S.aureus, and S.mutans, by two-way ANOVA and Tukey's honestly significant test (p>0.05)., Results: The highest anti-microbial values against all inspected microbial colonies were unveiled when disinfection was performed in combination i.e., H 2 O 2  + MI and PDT + MI and the least cleansing of impression material was seen by the control group as no treatment was provided. Solo application of MI was more effective than control, H 2 O 2 and 5-ALA activated by PDT but less active when used in combination method H 2 O 2 with MI and PDT with MI. PDT and control group showed the least antimicrobial effectiveness against E. coli (p<0.05) CONCLUSION: Disinfection of impression materials with combination therapies including photodynamic therapy with microwave irradiation and hydrogen peroxide with microwave irradiation displayed highest antimicrobial efficacies against E. coli, S. aureus, and S. mutans with no adverse effects on mechanical properties of impression material., (Copyright © 2022. Published by Elsevier B.V.)

Background: Decline of lymphatic vessel (LV) density and function in intrinsically aged skin can lead to harmful substance accumulation and fluid imbalance. Whether it will be improved by low dose ALA-PDT needs to be investigated., Aims: To investigate the effect of low dose ALA-PDT on remodeling LVs in intrinsically aged skin., Methods: Low dose ALA-PDT with 3 sessions were applied on the dorsal skin of intrinsically aged SKH-1 mice (15 months old). Skin biopsies were obtained from young mice (4 months old, Young-control), intrinsically aged mice before PDT (Old-pre-PDT), and after PDT at different time points (Old-PDT-24h, Old-PDT-1w, Old-PDT-4w), and skin phenotypes were evaluated by dermoscopy. The structure of LVs and extracellular matrix were evaluated via immunofluorescence staining and HE. The drainage function of LVs was evaluated by Evans Blue assay in vivo. The expression of Calcium-binding EGF domain-containing protein 1 (CCBE1), VE-cadherin, and the activation of VEGF-C/VEGFR3 signaling pathway were evaluated by ELISA and Western Blot., Results: The density of LVs decreased and the lymphatic clearance was significantly delayed in aged skin. Low dose ALA-PDT increased the density of LVs and blood vessels. The clearance of Evans Blue assay showed the drainage function of LVs was improved after PDT treatments in vivo. The VE-cadherin and VEGF-C/VEGFR3 pathway up-regulated in intrinsically aged skin after ALA-PDT treatments., Conclusions: LVs in intrinsically aged skin were remodeled and their function were restored by low dose ALA-PDT via up-regulating the VEGF-C/VEGFR3 pathway and stimulating the expression of VE-cadherin., (Copyright © 2022. Published by Elsevier B.V.)

Background: The skin infection caused by Mycobacterium abscessus (M. abscessus) is extremely difficult to treat in clinical practice. PDT (photodynamic therapy) is a promising antibacterial treatment. We evaluated the effect of photodynamic therapy using 5-aminolevulinic acid (ALA) as a photosensitizer on M. abscessus and its antibiotic resistance in this study., Methods: M. abscessus and biofilm were treated with different concentrations of ALA and then irradiated with LED light (635 nm, 80 J/cm 2 ), while there were ALA-only group, light-only group, and negative control group. The effects were observed by colony counting, crystal violet staining, confocal laser scanning microscope (CLSM), and scanning electron microscope (SEM). The changes of drug susceptibility of M. abscessus at sublethal doses were detected by micro-broth dilution method, and the possible mechanism was explored by fluorometer and real-time fluorescence quantitative Polymerase Chain Reaction (RT-qPCR)., Results: ALA-PDT showed a significant killing effect on M. abscessus at ALA concentrations greater than 50 μg/ml and the effect increased with increasing photosensitizer concentrations. ALA-PDT also showed a notable scavenging effect on M. abscessus biofilm, which was also enhanced with increasing ALA concentrations. At sublethal doses, the susceptibility of M. abscessus to antibiotics was increased, and ALA-PDT greatly increased the cell wall permeability of M. abscessus and decreased the mRNA expression of drug resistance genes whiB7 and erm (41), as well as efflux pump genes MAB&#95;1409c and MAB&#95;3142c at the transcriptional level., Conclusions: ALA-PDT has a significant killing effect on M. abscessus and can increase its antibiotic susceptibility., (Copyright © 2022. Published by Elsevier B.V.)

Oral squamous cell carcinoma (OSCC) can be characterized by severe functional impairment and a poor prognosis. The epidermal growth factor receptor (EGFR) is highly expressed in OSCC and is a promising target for cancer therapy. In addition, aminolevulinic acid-induced photodynamic therapy (ALA-PDT) has produced robust clinical effects in oral cancer. Here, an EGFR inhibitor, nimotuzumab, was administered to 2 OSCC cell lines, CAL-27 and SCC-25, treated with ALA-PDT. Cell growth, apoptosis, and reactive oxygen species (ROS) generation were used to measure the antitumor activity of the combination therapy. The in vivo effect of nimotuzumab plus ALA-PDT was done using a mouse OSCC xenograft model (SCC-25). EGFR expression was further compared by Western blotting in different groups. We observed that nimotuzumab combined with ALA-PDT could enhance inhibition of OSCC cell growth in vitro and in vivo. We also observed an enhanced effect after combination on cell apoptosis in CAL-27 and SCC-25 cells. Furthermore, combined therapy significantly reduced the protein expression levels of EGFR in vitro. However, we observed that nimotuzumab plus ALA-PDT did not increase ROS generation substantially in OSCC cells compared to the ALA-PDT group alone. These observations indicate that nimotuzumab combined with ALA-PDT has valuable applications for OSCC treatment., (Copyright © 2022. Published by Elsevier B.V.)

Background: 5-aminolevulinic acid-mediated PDT (ALA-PDT) has been used in a variety of skin diseases including cSCC (cutaneous squamous cell carcinoma). Halofuginone (HL) is a less-toxic febrifugine derivative and has inhibitory effects on a variety of cancer cells. For now, there are no published study focusing on the combination use of ALA-PDT with HL to improve clinical efficacy of cSCC., Objective: In this study, we will examine the effectiveness of combined treatment of ALA-PDT and HL in cSCC as well as its underlying mechanism., Methods: The human epidermoid carcinoma cell line SCL-1 was treated with ALA-PDT or/ and HL, and cell viability, cell migration, ROS production, apoptosis were evaluated by CCK-8, colony formation, scratch assay, DCFH-DA probe, flow cytometry, respectively. The protein expression of NRF2 signaling was examined by western blot., Results: HL strengthened ALA-PDT's inhibition of SCL-1 cell viability, migration, as well as NRF2 related β-catenin, p-Erk1/2, p-Akt and p-S6K1 expression. Overexpression of NRF2 conferred resistance to co-treatment's effects on c-Myc, Cyclin D1, Bcl-2, as well as cell proliferation. HL also strengthened ALA-PDT's inhibition of tumor volume in cSCC mouse model and elevated ROS generation of ALA-PDT., Conclusion: HL enhances the anti-tumor effect of ALA-PDT in vitro and in vivo. HL has the potential to enhance the anti-tumor effect of ALA-PDT in cSCC via inhibiting NRF2 signaling., (Copyright © 2021. Published by Elsevier B.V.)

Photodynamic Therapy (PDT) is an oncologic treatment, producing reactive oxygen species (ROS) to induce the death of cancer cells. This study aimed to evaluate the action of PDT on gliosarcoma cells, using protoporphyrin IX as PS by incubation with the precursor aminolevulinic acid (ALA). An LED device was used with a light dose of 10 J/cm². The success of the therapy proved to be dependent on the concentration of ALA, and an incubation time of 4 h required for an effective response. Cell death was prevalent due to necrosis when assessed 18 h post-PDT. ALA proved to be an option to PDT in cells of the 9 L/lacZ, with the protocol tested., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Condyloma acuminatum (CA) is a common sexually transmitted disease caused by human papillomaviruses. Five-aminolevulinic acid-photodynamic therapy (ALA-PDT) can promote the apoptosis of keratinocytes and inhibit proliferation; however, the effect of ALA-PDT on the immune mechanism of CA tissue is not well understood. In this study, we examined the changes in Toll-like receptor 4 (TRL4) and nuclear factor kappa B (NF-κB) expression in CA tissues before ALA-PDT treatment to determine its effects and possible immune mechanisms., Methods: Immunohistochemistry (streptavidin-peroxidase) was used to detect the expression of TLR4 and NF-κB in the keratinocytes of the patients with CA before and after ALA-PDT treatment., Results: Before treatment, the positive TLR4 and NF-κB expression rates in the keratinocytes of the patients with CA were 86.53% (45/52) and 94.23% (49/52), respectively, whereas after treatment, these rates were 44.23% (23/52) and 38.46% (20/52), respectively. Positive TLR4 and NF-κB expression in the keratinocytes of CA was mostly ++ to +++ in intensity before ALA-PDT and mostly ranged from - to + after treatment. The positive expression rate and intensity of TLR4 and NF-κB in the two groups before and after ALA-PDT were significantly different (P < 0.05). There was a positive correlation between the expression of TLR4 and NF-κB in the CA tissues after ALA-PDT (r = 0.486, P < 0.05)., Conclusions: ALA-PDT may relieve local immunosuppressive states by reducing TLR4 and NF-κB expression and jointly promoting CA regression, which is a potential molecular mechanism of ALA-PDT in CA treatment., (Copyright © 2021. Published by Elsevier B.V.)

Background: Acne vulgaris is a chronic inflammatory skin disease around pilosebaceous unit. 5-Aminolaevulinic acid photodynamic therapy (ALA-PDT) is an effective therapy for severe acne vulgaris. However, its specific treatment mechanism remains unclear. In the present study, we investigated the potential mechanism of how ALA-PDT induced lipid secretion inhibition in acne vulgaris., Methods: Primary human sebocytes and sebaceous gland of golden hamster were treated with/without ALA-PDT. Cell viability was evaluated by Live/Dead Cell assay. Fluorescence microscope was used to observe lipids secretion in sebocytes after Nile red staining. The expression of SREBP-1 after ALA-PDT was evaluated by qRT-PCR. Regulation of ALA-PDT on AMPK/SREBP-1 was evaluated by western blot., Results: The results showed that ALA-PDT suppressed lipid secretion of primary human sebocytes. In addition, ALA-PDT could inhibit the expression of SREBP-1 in vitro. We also found that ALA-PDT activated AMPK pathway, down-regulating the expression of SREBP-1 in sebocytes after ALA-PDT., Conclusions: These findings elucidate that ALA-PDT suppresses lipid secretion through AMPK/SREBP-1 pathway in treatment of acne vulgaris., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Chordoma are uncommon aggressive tumors of the skeleton. Surgical resection is often subtotal and adjuvant treatment possibilities are limited as chordomas are highly chemo- and radioresistant. In the present study we examined the impact of 5-ALA PDT on different human chordoma cell lines. Furthermore, we investigated the variation of two parameters: (1.) 5-ALA incubation time and (2.) supplemental use of ciprofloxacin as iron chelator., Methods: Experiments were realized in vitro with three different human chordoma cell lines: U-CH2, U-CH2B and U-CH14. After pre-incubation for 24 h with various concentrations of ciprofloxacin (1.5 - 5.0 μg/ml), different amounts of 5-ALA (15 - 50 μg/ml) were applied to the cells either for a brief (4 h) or a long (6 h) incubation time. Subsequently cells were exposed to photodynamic radiation. Cell viability was exploited by WST-1 assay. Thus, for each of the three cell lines, two drug combinations (ciprofloxacin plus 5-ALA and 5-ALA only) and two incubation times (short, 4 h and long, 6 h) were tested. Negative control groups were also examined., Results: Supplemental use of ciprofloxacin led to increased cell death in each of the cell lines. Different 5-ALA incubation times (4 h vs. 6 h) showed no significant differences in cell viability except for U-CH2., Conclusion: Ciprofloxacin as an ordinary applied antibiotic, enhanced the effect of 5-ALA PDT on different human chordoma cell lines in vitro. The impact was dependent on the dose of ciprofloxacin-5-ALA. There were no notable differences for the tested 5-ALA incubation times. In human chordoma cell lines 5-ALA PDT may effectively be amended by ciprofloxacin., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Biofilm-associated Candida albicans (C. albicans) infections are hard to cure due to their high levels of resistance to antifungal agents. Photodynamic therapy (PDT) is a promising approach for controlling infections caused by C. albicans. This study was designed to explore the inhibitory activity of PDT using 5-aminolevulinic acid (ALA) as photosensitizer against C. albicans biofilms., Methods: C. albicans cell suspensions were incubated for 48 h to form mature biofilms. ALA solution was diluted to 15 mM and incubated with C. albicans biofilms for 5 h before irradiated by red light semiconductor laser under the light intensity of 300 J/cm 2 and fluence rate of 100 mW/cm 2 for 50 min. The inhibitory activity was evaluated from subcellular level, molecular level and transcriptional level using transmission electron microscopy (TEM) observation, flow cytometry analysis and quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) assays, respectively., Results: From subcellular level, the degraded content of the cytoplasm, nuclear condensation and mitochondrial swelling were observed after ALA-PDT. From molecular level, ALA-PDT resulted in 19.4 % cell apoptosis. From transcriptional level, ALA-PDT significantly reduced the mRNA expressions of hyphae-specific genes (HWP1 and ALS3) and long-term biofilm maintenance genes (UME6 and HGC1), whereas ALA or red light alone had no significant effect., Conclusions: The inhibitory activity indicated that ALA-PDT may have the potential to serve as an antifungal strategy in eliminatingC. albicans biofilms., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aims and Background: High-risk human papillomavirus (HR-HPV) infection has been confirmed to be highly related to diseases such as Bowenoid papulosis, cervical cancer, and cervical intraepithelial neoplasia. 5-aminolevulinic acid-mediated PDT (ALA-PDT) has been used in a variety of HR-HPV infection-related diseases. Dihydroartemisinin (DHA) is one of artemisinin derivatives, and has inhibitory effects on a variety of cancer cells. For now, there is no published study focusing on the combination use of ALA-PDT with DHA to improve clinical efficacy of HR-HPV infection-related diseases. So in this study, we will examine the effectiveness of combined treatment of ALA-PDT and DHA for HR-HPV infection as well as its underlying mechanism., Methods: The human cervical cancer cell line HeLa (containing whole genome of HR-HPV18) was treated with ALA-PDT or/and DHA, and cell viability, long proliferation, ROS production and apoptosis were evaluated by CCK8, colony-forming assay, immunofluorescence and flow cytometry, respectively. The protein expression of NF-κB-HIF-1α-VEGF pathway and NRF2-HO-1 pathway was examined by western blot., Results: The results showed that DHA could enhance the effect of ALA-PDT on cell viability long proliferation, ROS production and apoptosis in HeLa cells. We also found that DHA inhibited NF-κB-HIF-1α-VEGF pathway which was activated by ALA-PDT. Besides, ALA-PDT combined with DHA activated NRF2-HO-1 pathway., Conclusion: Although the NRF2 - NO-1 pathway as a resistance mechanism remains unresolved, DHA has the potential to enhance the effect of ALA-PDT for HPV infection-related diseases through inhibiting NF-κB - HIF-1α - VEGF pathway., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Glioblastoma is the most severe form of brain cancer. Despite multimodal therapy combining surgery, radiotherapy and chemotherapy, prognosis of patients is dismal. It has been observed that the surgical resection guided by photosensitizer fluorescence followed by photodynamic therapy (PDT) prolongs the average survival in patients with glioblastoma. The main problem with all oncological treatments, including PDT, is the presence of resistant cells. The objective of this study was to isolate and perform an initial characterization of human glioblastoma cells resistant to PDT employing methyl-5-aminolevulinic acid. We obtained resistant cells from the T98 G cell line. Resistant populations accumulated less photosensitizer, formed spheroids of higher number of cells, had higher tumorigenic capacity, and expressed higher mRNA levels of fibroblastic growth factor receptor (FGFR), epidermal growth factor receptor (EGFR) and β-platelet-derived growth factor receptor (βPDGFR) than parental cells. The studies of glioblastoma resistance to PDT would help to better understand the causes of tumor recurrence after PDT and to develop new therapeutic proposals in this field of oncology., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objective: To investigate the effect of 5-aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) on the invasion and metastasis in cutaneous squamous cell carcinoma (cSCC) cell line(SCL-1) and to study whether the effect was via the MTSS1 gene and p63 gene related pathways., Methods: SCL-1 cells were cultured and submitted to ALA-PDT treatment (ALA-PDT group), ALA treatment alone (ALA group), LED illumination alone (LED group) and remains untreated (control group). Scratch test, Transwell migration chamber assay and Matrigel cell invasion assay were used to detect the ability of migration and invasion of SCL-1 cells after treatment. The mRNA levels and protein expressions of tumor metastasis suppressor gene (MTSS1) and p63 gene were further detected by using quantitative real-time PCR and flow cytometry assay respectively after treatment., Results: The migration and invasion abilities of SCL-1 cells after treatment were significantly reduced in the ALA-PDT groups than that in ALA group, LED group and control group (P＜0.05). Both the mRNA and protein expression levels of MTSS1 gene were up-regulated, while the mRNA and protein expression levels of p63 gene were down-regulated after ALA-PDT treatment., Conclusion: ALA-PDT suppressed the migration and invasion of human cSCC cell line, probably via the MTSS1 gene and p63 gene related pathways. This study put forward a possible mechanism of invasion in SCL-1 cell, also providing a potential target for the therapy of cSCC., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Nanoparticles show promise for theranostic applications in cancer. The metal-based nanoparticles can be used both as photosensitizers and delivery vehicles. In bimetallic particles based on gold or silver and iron, a combination of the plasmonic features of the gold or silver components with the magnetic properties of the iron makes these hybrid nanomaterials suitable for both imaging and therapeutic applications. Herein, we discuss toxicity and cell internalization of metallic (silver and gold) and bimetallic (silver-iron, gold-iron, and silver-gold) aminolevulinic acid (ALA) nanoparticles. ALA can control the production of an intracellular photosensitizer, protoporphyrin IX (PpIX), commonly used in photodynamic therapy., Methods: Nanoparticles were synthesized by photoreduction method and characterized by UV/Vis spectra, Zeta potential, FTIR, XRD, and transmission electron microscopy. The amount of singlet oxygen generation by a yellow LED, and ultrasound was studied for gold, gold-iron, and silver-gold nanoparticles. Cytotoxicity assays of MCF-7 in the presence of nanoparticles were performed, and PpIX fluorescence was quantified by high content screening (HCS)., Results: Red fluorescence observed after 24 h of nanoparticles incubation on MCF-7 cells, indicated that the ALA in surface of nanoparticles was efficiently converted to PpIX. The best results for singlet oxygen generation with LED or ultrasound irradiation were obtained with ALA:AgAuNPs., Conclusions: The studied nanoparticles present the potential to deliver aminolevulinic acid to breast cancer cells efficiently, generate singlet oxygen, and convert ALA into PpIX inside the cells allowing photodiagnosis and therapies such as photodynamic and sonodynamic therapies., (Copyright © 2020 Elsevier B.V. All rights reserved.)