Photodynamic therapy for solid tumors: A review of the literature

Highly Efficient Quenching of Singlet Oxygen by DNA Origami Nanostructures

DNA origami nanostructures (DONs) are able to scavenge reactive oxygen species (ROS) and their scavenging efficiency toward ROS radicals was shown to be comparable to that of genomic DNA. Herein, we demonstrate that DONs are highly efficient singlet oxygen quenchers outperforming double-stranded (ds) DNA by several orders of magnitude. To this end, a ROS mixture rich in singlet oxygen is generated by light irradiation of the photosensitizer methylene blue and its cytotoxic effect on Escherichia coli cells is quantified in the presence and absence of DONs. DONs are found to be vastly superior to dsDNA in protecting the bacteria from ROS-induced damage and even surpass established ROS scavengers. At a concentration of 15 nM, DONs are about 50 000 times more efficient ROS scavengers than dsDNA at an equivalent concentration. This is attributed to the dominant role of singlet oxygen, which has a long diffusion length and reacts specifically with guanine. The dense packing of the available guanines into the small volume of the DON increases the overall quenching probability compared to a linear dsDNA with the same number of base pairs. DONs thus have great potential to alleviate oxidative stress caused by singlet oxygen in diverse therapeutic settings.

Photodynamic therapy with curcumin and near-infrared radiation as an antitumor strategy to glioblastoma cells

Glioblastoma is a malignant neoplasm that develops in the central nervous system and is characterized by high rates of cell proliferation and invasion, presenting resistance to treatments and a poor prognosis. Photodynamic therapy (PDT) is a therapeutic modality that can be applied in oncological cases and stands out for being less invasive. Photosensitizers (PS) of natural origin gained prominence in PDT. Curcumin (CUR) is a natural compound that has been used in PDT, considered a promising PS. In this work, we evaluated the effects of PDT-mediated CUR and near-infrared radiation (NIR) in glioblastoma cells. Through trypan blue exclusion analysis, we chose the concentration of 5 μM of CUR and the dose of 2 J/cm2 of NIR that showed better responses in reducing the viable cell number in the C6 cell line and did not show cytotoxic/cytostatic effects in the HaCat cell line. Our results show that there is a positive interaction between CUR and NIR as a PDT model since there was an increase in ROS levels, a decrease in cell proliferation, increase in cytotoxicity with cell death by autophagy and necrosis, in addition to the presence of oxidative damage to proteins. These results suggest that the use of CUR and NIR is a promising strategy for the antitumor application of PDT.

Advances in Medicine: Photodynamic Therapy

Over the past decades, medicine has made enormous progress, revolutionized by modern technologies and innovative therapeutic approaches. One of the most exciting branches of these developments is photodynamic therapy (PDT). Using a combination of light of a specific wavelength and specially designed photosensitizing substances, PDT offers new perspectives in the fight against cancer, bacterial infections, and other diseases that are resistant to traditional treatment methods. In today's world, where there is a growing problem of drug resistance, the search for alternative therapies is becoming more and more urgent. Imagine that we could destroy cancer cells or bacteria using light, without the need to use strong chemicals or antibiotics. This is what PDT promises. By activating photosensitizers using appropriately adjusted light, this therapy can induce the death of cancer or bacterial cells while minimizing damage to surrounding healthy tissues. In this work, we will explore this fascinating method, discovering its mechanisms of action, clinical applications, and development prospects. We will also analyze the latest research and patient testimonies to understand the potential of PDT for the future of medicine.

Photodynamic therapy with verteporfin accelerates apoptotic bleb formation in human ameloblastoma

OBJECTIVE

Although benign, ameloblastoma is a locally aggressive lesion in some patients and the development of additional treatments is needed. Verteporfin (VP) is a photosensitizer exhibiting considerable photocytotoxicity in various tumor cells. We aimed to investigate the effects of verteporfin photodynamic therapy (VP PDT) on ameloblastoma.

METHODS

Eighteen patients who underwent surgery for ameloblastoma were randomly selected. We performed an immunohistochemical assessment to investigate the expression of low-density lipoprotein receptor (LDLR) and Yes-associated protein (YAP), targets of VP, in human ameloblastoma tissues and cultured human ameloblastoma cell line (HAM1). The effect of VP PDT on cell proliferation and apoptosis in HAM1 was analyzed.

RESULTS

The expression of LDLR and YAP were detected in human ameloblastoma tissues and HAM1. LDLR expression was significantly higher in patients who had previously undergone surgery than in patients who were receiving it for the first time. The cytotoxic effect of the combination of low-concentration VP administration and laser irradiation was comparable to high-concentration VP administration with and without laser irradiation. The addition of laser irradiation to VP administration significantly accelerated apoptotic bleb formation compared with VP administration alone.

CONCLUSION

VP PDT has the potential to become an additional treatment for large-sized ameloblastoma.

Development of Novel Bimodal Agents Based on Near-Infrared BODIPY-Conjugated Hoechst Derivatives for Combined Use in Auger Electron and Photodynamic Cancer Therapy

Auger electron therapy and photodynamic therapy (PDT) have attracted attention as powerful anticancer modalities. Herein, we report the development of novel bimodal agents for Auger electron therapy and PDT, and their application to combination therapy. [125I]NBH-1/NBH-1 and [125I]NBH-2/NBH-2, composing Hoechst and iodostyryl-BODIPY, were synthesized and evaluated regarding their usefulness as bimodal agents. [125I]NBH-1 showed significantly higher nuclear uptake than [125I]NBH-2 and radioactivity-dependent cytotoxicity induced by Auger electrons. In addition, NBH-1 exhibited photoinduced cytotoxicity. Combination therapy using [125I]NBH-1 and NBH-1 with light irradiation induced a superior cytotoxicity to these treatments alone. In tumor-bearing mice injected with NBH-1 or [125I]NBH-1/NBH-1 under light irradiation, significant tumor growth inhibition was observed compared with that of the control group. Especially, [125I]NBH-1/NBH-1 under light irradiation showed the strongest therapeutic effects among all treatments. These results suggest that [125I]NBH-1/NBH-1 is a potent bimodal agent for Auger therapy and PDT and that combination therapy using [125I]NBH-1 and NBH-1 shows enhanced therapeutic efficacy.

A Portrait of the Chromophore as a Young System-Quantum-Derived Force Field Unraveling Solvent Reorganization upon Optical Excitation of Cyclocurcumin Derivatives

The study of fast non-equilibrium solvent relaxation in organic chromophores is still challenging for molecular modeling and simulation approaches, and is often overlooked, even in the case of non-adiabatic dynamics simulations. Yet, especially in the case of photoswitches, the interaction with the environment can strongly modulate the photophysical outcomes. To unravel such a delicate interplay, in the present contribution we resorted to a mixed quantum-classical approach, based on quantum mechanically derived force fields. The main task is to rationalize the solvent reorganization pathways in chromophores derived from cyclocurcumin, which are suitable for light-activated chemotherapy to destabilize cellular lipid membranes. The accurate and reliable decryption delivered by the quantum-derived force fields points to important differences in the solvent's reorganization, in terms of both structure and time scale evolution.

Self-Disassembling and Oxygen-Generating Porphyrin-Lipoprotein Nanoparticle for Targeted Glioblastoma Resection and Enhanced Photodynamic Therapy

The dismal prognosis for glioblastoma multiform (GBM) patients is primarily attributed to the highly invasive tumor residual that remained after surgical intervention. The development of precise intraoperative imaging and postoperative residual removal techniques will facilitate the gross total elimination of GBM. Here, a self-disassembling porphyrin lipoprotein-coated calcium peroxide nanoparticles (PLCNP) is developed to target GBM via macropinocytosis, allowing for fluorescence-guided surgery of GBM and improving photodynamic treatment (PDT) of GBM residual by alleviating hypoxia. By reducing self-quenching and enhancing lysosome escape efficiency, the incorporation of calcium peroxide (CaO2) cores in PLCNP amplifies the fluorescence intensity of porphyrin-lipid. Furthermore, the CaO2 core has diminished tumor hypoxia and improves the PDT efficacy of PLCNP, enabling low-dose PDT and reversing tumor progression induced by hypoxia aggravation following PDT. Taken together, this self-disassembling and oxygen-generating porphyrin-lipoprotein nanoparticle may serve as a promising all-in-one nanotheranostic platform for guiding precise GBM excision and empowering post-operative PDT, providing a clinically applicable strategy to combat GBM in a safe and effective manner.

Three-dimensional printing of the human lung pleural cavity model for PDT malignant mesothelioma

OBJECTIVE

The primary aim was to investigate emerging 3D printing and optical acquisition technologies to refine and enhance photodynamic therapy (PDT) dosimetry in the management of malignant pleural mesothelioma (MPM).

MATERIALS AND METHODS

A rigorous digital reconstruction of the pleural lung cavity was conducted utilizing 3D printing and optical scanning methodologies. These reconstructions were systematically assessed against CT-derived data to ascertain their accuracy in representing critical anatomic features and post-resection topographical variations.

RESULTS

The resulting reconstructions excelled in their anatomical precision, proving instrumental translation for precise dosimetry calculations for PDT. Validation against CT data confirmed the utility of these models not only for enhancing therapeutic planning but also as critical tools for educational and calibration purposes.

CONCLUSION

The research outlined a successful protocol for the precise calculation of light distribution within the complex environment of the pleural cavity, marking a substantive advance in the application of PDT for MPM. This work holds significant promise for individualizing patient care, minimizing collateral radiation exposure, and improving the overall efficiency of MPM treatments.

Molecular engineering of a spheroid-penetrating phage nanovector for photodynamic treatment of colon cancer cells

Photodynamic therapy (PDT) represents an emerging strategy to treat various malignancies, including colorectal cancer (CC), the third most common cancer type. This work presents an engineered M13 phage retargeted towards CC cells through pentavalent display of a disulfide-constrained peptide nonamer. The M13CC nanovector was conjugated with the photosensitizer Rose Bengal (RB), and the photodynamic anticancer effects of the resulting M13CC-RB bioconjugate were investigated on CC cells. We show that upon irradiation M13CC-RB is able to impair CC cell viability, and that this effect depends on i) photosensitizer concentration and ii) targeting efficiency towards CC cell lines, proving the specificity of the vector compared to unmodified M13 phage. We also demonstrate that M13CC-RB enhances generation and intracellular accumulation of reactive oxygen species (ROS) triggering CC cell death. To further investigate the anticancer potential of M13CC-RB, we performed PDT experiments on 3D CC spheroids, proving, for the first time, the ability of engineered M13 phage conjugates to deeply penetrate multicellular spheroids. Moreover, significant photodynamic effects, including spheroid disruption and cytotoxicity, were readily triggered at picomolar concentrations of the phage vector. Taken together, our results promote engineered M13 phages as promising nanovector platform for targeted photosensitization, paving the way to novel adjuvant approaches to fight CC malignancies.

A Comprehensive Review of Various Therapeutic Strategies for the Management of Skin Cancer

Skin cancer (SC) poses a global threat to the healthcare system and is expected to increase significantly over the next two decades if not diagnosed at an early stage. Early diagnosis is crucial for successful treatment, as the disease becomes more challenging to cure as it progresses. However, identifying new drugs, achieving clinical success, and overcoming drug resistance remain significant challenges. To overcome these obstacles and provide effective treatment, it is crucial to understand the causes of skin cancer, how cells grow and divide, factors that affect cell growth, and how drug resistance occurs. In this review, we have explained various therapeutic approaches for SC treatment via ligands, targeted photosensitizers, natural and synthetic drugs for the treatment of SC, an epigenetic approach for management of melanoma, photodynamic therapy, and targeted therapy for BRAF-mutated melanoma. This article also provides a detailed summary of the various natural drugs that are effective in managing melanoma and reducing the occurrence of skin cancer at early stages and focuses on the current status and future prospects of various therapies available for the management of skin cancer.

Advances in research and application of photodynamic therapy in cholangiocarcinoma (Review)

Cholangiocarcinoma (CCA) is a disease characterized by insidious clinical manifestations and challenging to diagnose. Patients are usually diagnosed at an advanced stage and miss the opportunity for radical surgery. Therefore, effective palliative therapy is the main treatment approach for unresectable CCA. Current common palliative treatments include biliary drainage, chemotherapy, radiotherapy, targeted therapy and immunotherapy. However, these treatments only offer limited improvement in quality of life and survival. Photodynamic therapy (PDT) is a novel local treatment method that is considered a safe tumor ablation method for numerous cancers. It has shown good efficacy in various studies of CCA and is expected to become an important treatment for CCA. In the present study, the mechanisms of PDT in the treatment of CCA were systematically explored and the progress in the research of photosensitizers was discussed. The current study focused on the various PDT protocols and their therapeutic effects in CCA, with the objective of providing a new horizon for future research and clinical applications of PDT in the treatment of CCA.

Cracking a cancer code DNA methylation in epigenetic modification: an in-silico approach on efficacy assessment of Sri Lanka-oriented nutraceuticals

DNA methyltransferase (DNMTs) are essential epigenetic modifiers that play a critical role in gene regulation. These enzymes add a methyl group to cytosine's 5'-carbon, specifically within CpG dinucleotides, using S-adenosyl-L-methionine. Abnormal overexpression of DNMTs can alter the gene expression patterns and contribute to cancer development in the human body. Therefore, the inhibition of DNMT is a promising therapeutic approach to cancer treatment. This study was aimed to identify potential nutraceutical inhibitors from the Sri Lanka Flora database using computational methods, which provided an atomic-level description of the drug binding site and examined the interactions between nutraceuticals and amino acids of the DNMT enzyme. A series of nutraceuticals from Sri Lanka-oriented plants were selected and evaluated to assess their inhibitory effects on DNMT using absorption, distribution, metabolism, excretion and toxicity analysis, virtual screening, molecular docking, molecular dynamics simulation and trajectory analysis. Azacitidine, a DNMT inhibitor approved by the US Food and Drug Administration, was selected as a reference inhibitor. The complexes with more negative binding energies were selected and further assessed for their potency. Seven molecules were identified from 200 nutraceuticals, demonstrating significantly negative binding energies against the DNMT enzyme. Various trajectory analyses were conducted to investigate the stability of the DNMT enzyme. The results indicated that petchicine (NP#0003), ouregidione (NP#0011) and azacitidine increased the stability of the DNMT enzyme. Consequently, these two nutraceuticals showed inhibitory efficacies similar to azacitidine, making them potential candidates for therapeutic interventions targeting DNMT enzyme-related cancers. Additional bioassay testing is recommended to confirm the efficacies of these nutraceuticals and explore their applicability in clinical treatments.Communicated by Ramaswamy H. Sarma.

Pharmaceutical Approach to Develop Novel Photosensitizer Nanoformulation: An Example of Design and Characterization Rationale of Chlorophyll α Derivative

In this study, we described physico-chemical properties of novel nanoformulation of photosensitizer-pyropheophorbide α 17-diethylene glycol ester (XL) (chlorophyll α derivative), revealing insights into antitumor activity and maintaining quality, meeting the pharmaceutical approach of new nanoformulation design. Our formulation, based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles, increased XL solubility and selective tumor-targeted accumulation. In our research, we revealed, for the first time, that XL binding to polyvinyl alcohol (PVA) enhances XL photophysical activity, providing the rationale for PVA application as a stabilizer for nanoformulations. Results of FTIR, DSC, and XRD revealed the physical interactions between XL and excipients, including PVA, indicating that the encapsulation maintained XL binding to PVA. The encapsulated XL exhibited higher photophysical activity compared to non-encapsulated substance, which can be attributed to the influence of residual PVA. Gamma-irradiation led to degradation of XL; however, successful sterilization of the samples was achieved through the filtration. Importantly, the encapsulated and sterilized XL retained cytotoxicity against both 2D and 3D tumor cell models, demonstrating the potential of the formulated NP-XL for photodynamic therapy applications, but lacked the ability to reactivate epigenetically silenced genes. These findings provide valuable insights into the design and characterization of PLGA-based nanoparticles for the encapsulation of photosensitizers.

Light dose effect of photodynamic therapy on growth inhibition and apoptosis induction in non-small cell lung cancer: A study in nude mouse model

BACKGROUND

Photodynamic therapy (PDT) is receiving increasing attention in treating non-small cell lung cancer (NSCLC) worldwide, but in clinical practice, the relationship between treatment effect and PDT light dose in NSCLC remains unclear. Therefore, we aimed to determine the optimal light dose for PDT by exploring molecular biomarkers and evaluating tumor growth data.

METHODS

We applied bioinformatics to identify promising genes and pathways in NSCLC and PDT. Then, the human lung adenocarcinoma cell line A549-bearing BALB/c nude mice were treated with hematoporphyrin derivative (HPD, 3 mg/kg) that is currently used widely for lung cancer treatment in the world even with photosensitization issues. After 48 h, tumor-bearing mice were irradiated superficially at doses of 100, 200, 300, 400, and 500 J/cm2. The tumor growth data and apoptotic molecules were assessed and calculated.

RESULTS

Bioinformatics results indicated that the apoptosis pathway was significantly enriched and caspase 3 was the most promising biomarker on prognosis in NSCLC-PDT. Compared to the untreated group, there was no difference in the relative tumor volume (RTV) of the 100 J/cm2 group, while the RTV of the other treatment groups (200-500 J/cm2) was significantly lower. In the 100 J/cm2 group, there were significant differences in the complete remission (CR, 0 %) and the percentage of tumor growth inhibition rate (TGI%) over 75 % (20 %) compared with the other treatment groups, especially the 300 and 400 J/cm2 groups (CR 70 %; TGI% 90 %). In the 300 and 400 J/cm2 groups, the expression of caspase 3, cleaved-caspase 3, PARP1, and Bax was increased significantly, while Bcl-2 expression was significantly lower.

CONCLUSIONS

Moderate doses of PDT (300 or 400 J/cm2) are more effective than low (100 or 200 J/cm2) or high doses (500 J/cm2) in the A549 tumor-bearing mice model. Since the A549 tumor is more akin to human tumors in pathological behavior, these experimental data may contribute to improving HPD-PDT illumination protocols for favorable clinical outcomes.

Cellular Mechanisms of Singlet Oxygen in Photodynamic Therapy

In this review, we delve into the realm of photodynamic therapy (PDT), an established method for combating cancer. The foundation of PDT lies in the activation of a photosensitizing agent using specific wavelengths of light, resulting in the generation of reactive oxygen species (ROS), notably singlet oxygen (1O2). We explore PDT's intricacies, emphasizing its precise targeting of cancer cells while sparing healthy tissue. We examine the pivotal role of singlet oxygen in initiating apoptosis and other cell death pathways, highlighting its potential for minimally invasive cancer treatment. Additionally, we delve into the complex interplay of cellular components, including catalase and NOX1, in defending cancer cells against PDT-induced oxidative and nitrative stress. We unveil an intriguing auto-amplifying mechanism involving secondary singlet oxygen production and catalase inactivation, offering promising avenues for enhancing PDT's effectiveness. In conclusion, our review unravels PDT's inner workings and underscores the importance of selective illumination and photosensitizer properties for achieving precision in cancer therapy. The exploration of cellular responses and interactions reveals opportunities for refining and optimizing PDT, which holds significant potential in the ongoing fight against cancer.

Temoporfin-Conjugated Upconversion Nanoparticles for NIR-Induced Photodynamic Therapy: Studies with Pancreatic Adenocarcinoma Cells In Vitro and In Vivo

Upconverting nanoparticles are interesting materials that have the potential for use in many applications ranging from solar energy harvesting to biosensing, light-triggered drug delivery, and photodynamic therapy (PDT). One of the main requirements for the particles is their surface modification, in our case using poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) and temoporfin (THPC) photosensitizer to ensure the colloidal and chemical stability of the particles in aqueous media and the formation of singlet oxygen after NIR irradiation, respectively. Codoping of Fe2+, Yb3+, and Er3+ ions in the NaYF4 host induced upconversion emission of particles in the red region, which is dominant for achieving direct excitation of THPC. Novel monodisperse PMVEMA-coated upconversion NaYF4:Yb3+,Er3+,Fe2+ nanoparticles (UCNPs) with chemically bonded THPC were found to efficiently transfer energy and generate singlet oxygen. The cytotoxicity of the UCNPs was determined in the human pancreatic adenocarcinoma cell lines Capan-2, PANC-01, and PA-TU-8902. In vitro data demonstrated enhanced uptake of UCNP@PMVEMA-THPC particles by rat INS-1E insulinoma cells, followed by significant cell destruction after excitation with a 980 nm laser. Intratumoral administration of these nanoconjugates into a mouse model of human pancreatic adenocarcinoma caused extensive necrosis at the tumor site, followed by tumor suppression after NIR-induced PDT. In vitro and in vivo results thus suggest that this nanoconjugate is a promising candidate for NIR-induced PDT of cancer.

β-Cyclodextrin Nanophotosensitizers for Redox-Sensitive Delivery of Chlorin e6

The aim of this study is to prepare redox-sensitive nanophotosensitizers for the targeted delivery of chlorin e6 (Ce6) against cervical cancer. For this purpose, Ce6 was conjugated with β-cyclodextrin (bCD) via a disulfide bond, creating nanophotosensitizers that were fabricated for the redox-sensitive delivery of Ce6 against cancer cells. bCD was treated with succinic anhydride to synthesize succinylated bCD (bCDsu). After that, cystamine was attached to the carboxylic end of bCDsu (bCDsu-ss), and the amine end group of bCDsu-ss was conjugated with Ce6 (bCDsu-ss-Ce6). The chemical composition of bCDsu-ss-Ce6 was confirmed with 1H and 13C NMR spectra. bCDsu-ss-Ce6 nanophotosensitizers were fabricated by a dialysis procedure. They formed small particles with an average particle size of 152.0 ± 23.2 nm. The Ce6 release rate from the bCDsu-ss-Ce6 nanophotosensitizers was accelerated by the addition of glutathione (GSH), indicating that the bCDsu-ss-Ce6 nanophotosensitizers have a redox-sensitive photosensitizer delivery capacity. The bCDsu-ss-Ce6 nanophotosensitizers have a low intrinsic cytotoxicity against CCD986Sk human skin fibroblast cells as well as Ce6 alone. However, the bCDsu-ss-Ce6 nanophotosensitizers showed an improved Ce6 uptake ratio, higher reactive oxygen species (ROS) production, and phototoxicity compared to those of Ce6 alone. GSH addition resulted in a higher Ce6 uptake ratio, ROS generation, and phototoxicity than Ce6 alone, indicating that the bCDsu-ss-Ce6 nanophotosensitizers have a redox-sensitive biological activity in vitro against HeLa human cervical cancer cells. In a tumor xenograft model using HeLa cells, the bCDsu-ss-Ce6 nanophotosensitizers efficiently accumulated in the tumor rather than in normal organs. In other words, the fluorescence intensity in tumor tissues was significantly higher than that of other organs, while Ce6 alone did not specifically target tumor tissue. These results indicated a higher anticancer activity of bCDsu-ss-Ce6 nanophotosensitizers, as demonstrated by their efficient inhibition of the growth of tumors in an in vivo animal tumor xenograft study.

An injectable and thermosensitive hydrogel with nano-aided NIR-II phototherapeutic and chemical effects for periodontal antibacteria and bone regeneration

Periodontitis is a common public health problem worldwide and an inflammatory disease with irregular defect of alveolar bone caused by periodontal pathogens. Both antibacterial therapy and bone regeneration are of great importance in the treatment of periodontitis. In this study, injectable and thermosensitive hydrogels with 3D networks were used as carriers for controlled release of osteo-inductive agent (BMP-2) and Near Infrared Region-II (NIR-II) phototherapy agents (T8IC nano-particles). T8IC nano-particles were prepared by reprecipitation and acted as photosensitizer under 808 nm laser irradiation. Besides, we promoted photodynamic therapy (PDT) through adding H2O2 to facilitate the antibacterial effect instead of increasing the temperature of photothermal therapy (PTT). Hydrogel + T8IC + Laser + BMP-2 + H2O2 incorporated with mild PTT (45 °C), enhanced PDT and sustained release of BMP-2. It was present with excellent bactericidal effect, osteogenic induction and biosafety both in vitro and in vivo. Besides, immunohistochemistry staining and micro-CT analyses had confirmed that PTT and PDT could promote bone regeneration through alleviating inflammation state. Altogether, this novel approach with synergistic antibacterial effect, anti-inflammation and bone regeneration has a great potential for the treatment of periodontitis in the future.

Cancer Metabolism as a Therapeutic Target and Review of Interventions

Cancer is amenable to low-cost treatments, given that it has a significant metabolic component, which can be affected through diet and lifestyle change at minimal cost. The Warburg hypothesis states that cancer cells have an altered cell metabolism towards anaerobic glycolysis. Given this metabolic reprogramming in cancer cells, it is possible to target cancers metabolically by depriving them of glucose. In addition to dietary and lifestyle modifications which work on tumors metabolically, there are a panoply of nutritional supplements and repurposed drugs associated with cancer prevention and better treatment outcomes. These interventions and their evidentiary basis are covered in the latter half of this review to guide future cancer treatment.

Zebrafish in Lung Cancer Research

Zebrafish is increasingly used as a model organism for cancer research because of its genetic and physiological similarities to humans. Modeling lung cancer (LC) in zebrafish has received significant attention. This review focuses on the insights gained from using zebrafish in LC research. These insights range from investigating the genetic and molecular mechanisms that contribute to the development and progression of LC to identifying potential drug targets, testing the efficacy and toxicity of new therapies, and applying zebrafish for personalized medicine studies. This review provides a comprehensive overview of the current state of LC research performed using zebrafish, highlights the advantages and limitations of this model organism, and discusses future directions in the field.

Bioorthogonally Assisted Phototherapy: Recent Advances and Prospects

Photoresponsive materials offer excellent spatiotemporal control over biological processes and the emerging phototherapeutic methods are expected to have significant effects on targeted cancer therapies. Recent examples show that combination of photoactivatable approaches with bioorthogonal chemistry enhances the precision of targeted phototherapies and profound implications are foreseen particularly in the treatment of disperse/diffuse tumors. The extra level of on-target selectivity and improved spatial/temporal control considerably intensified related bioorthogonally assisted phototherapy research. The anticipated growth of further developments in the field justifies the timeliness of a brief summary of the state of the art.

Photodynamic therapy (PDT) for oral leukoplakia: a systematic review and meta-analysis of single-arm studies examining efficacy and subgroup analyses

OBJECTIVE

This study aims to evaluate the efficacy of photodynamic therapy (PDT) in the treatment of oral leukoplakia and explore the subgroup factors that may influence its effectiveness.

METHODS

A systematic search was conducted in PubMed, Embase, the Cochrane Library, and Web of Science databases to identify relevant studies. Meta-analysis was performed using Stata15.0 software. Cochran's Q test and I2 statistics were used to evaluate heterogeneity, egger's test was used to evaluate publication bias.

RESULTS

The analysis of 17 studies included in this study suggests that PDT may be effective in achieving complete response (CR) [ES = 0.50, 95%CI: (0.33,0.66)], partial response (PR) [ES = 0.42, 95%CI: (0.27,0.56)], no response (NR) [ES = 0.19, 95%CI: (0.11,0.27)]in patients with oral leukoplakia. The recurrence rate was also evaluated [ES = 0.13, 95%CI: (0.08,0.18)]. Subgroup analysis showed that various factors such as light source, wavelength, medium, duration of application, clinical and pathological diagnosis classification influenced efficacy of PDT. The lesion areas of the leukoplakia after treatment were reduced by 1.97cm2 compared with those before treatment.

CONCLUSION

Our findings show that PDT is a viable treatment for oral leukoplakia. However, the effectiveness of the therapy may depend on several factors, as suggested by our subgroup analyses. (Registration no. CRD42023399848 in Prospero, 26/02/2023).

Advanced Light Source Technologies for Photodynamic Therapy of Skin Cancer Lesions

Photodynamic therapy (PDT) is an increasingly popular dermatological treatment not only used for life-threatening skin conditions and other tumors but also for cosmetic purposes. PDT has negligible effects on underlying functional structures, enabling tissue regeneration feasibility. PDT uses a photosensitizer (PS) and visible light to create cytotoxic reactive oxygen species, which can damage cellular organelles and trigger cell death. The foundations of modern photodynamic therapy began in the late 19th and early 20th centuries, and in recent times, it has gained more attention due to the development of new sources and PSs. This review focuses on the latest advancements in light technology for PDT in treating skin cancer lesions. It discusses recent research and developments in light-emitting technologies, their potential benefits and drawbacks, and their implications for clinical practice. Finally, this review summarizes key findings and discusses their implications for the use of PDT in skin cancer treatment, highlighting the limitations of current approaches and providing insights into future research directions to improve both the efficacy and safety of PDT. This review aims to provide a comprehensive understanding of PDT for skin cancer treatment, covering various aspects ranging from the underlying mechanisms to the latest technological advancements in the field.

Photodynamic Therapy for Colorectal Cancer: An Update and a Look to the Future

This review provides an update on the current state of photodynamic therapy (PDT) for colorectal cancer (CRC) and explores potential future directions in this field. PDT has emerged as a promising minimally invasive treatment modality that utilizes photosensitizers and specific light wavelengths to induce cell death in targeted tumor tissues. In recent years, significant progress has been made in understanding the underlying mechanisms, optimizing treatment protocols, and improving the efficacy of PDT for CRC. This article highlights key advancements in PDT techniques, including novel photosensitizers, light sources, and delivery methods. Furthermore, it discusses ongoing research efforts and potential future directions, such as combination therapies and nanotechnology-based approaches. By elucidating the current landscape and providing insights into future directions, this review aims to guide researchers and clinicians in harnessing the full potential of PDT for the effective management of CRC.

Combination of Two Photosensitisers in Anticancer, Antimicrobial and Upconversion Photodynamic Therapy

Photodynamic therapy (PDT) is a special form of phototherapy in which oxygen is needed, in addition to light and a drug called a photosensitiser (PS), to create cytotoxic species that can destroy cancer cells and various pathogens. PDT is often used in combination with other antitumor and antimicrobial therapies to sensitise cells to other agents, minimise the risk of resistance and improve overall outcomes. Furthermore, the aim of combining two photosensitising agents in PDT is to overcome the shortcomings of the monotherapeutic approach and the limitations of individual agents, as well as to achieve synergistic or additive effects, which allows the administration of PSs in lower concentrations, consequently reducing dark toxicity and preventing skin photosensitivity. The most common strategies in anticancer PDT use two PSs to combine the targeting of different organelles and cell-death mechanisms and, in addition to cancer cells, simultaneously target tumour vasculature and induce immune responses. The use of PDT with upconversion nanoparticles is a promising approach to the treatment of deep tissues and the goal of using two PSs is to improve drug loading and singlet oxygen production. In antimicrobial PDT, two PSs are often combined to generate various reactive oxygen species through both Type I and Type II processes.

Recent applications of phase-change materials in tumor therapy and theranostics

Phase-change materials (PCMs) are a type of special material which can store and release a large amount of thermal energy without any significant temperature change. They are emerging in recent years as a promising functional material in tumor therapy and theranostics due to their accurate responses to the temperature variations, biocompatibility and low toxicity. In this review, we will introduce the main types of PCMs and their desirable physiochemical properties for biomedical applications, and highlight the recent progress of PCM's applications in the modulated release of antitumor drugs, with special attentions paid to various ways to initiate temperature-dependent phase change, the concomitant thermal therapy and its combination with or activation of other therapies, particularly unconventional therapies. We will also summarize PCM's recent applications in tumor theranostics, where both drugs and imaging probes are delivered by PCMs for controlled drug release and imaging-guided therapy. Finally, the future perspectives and potential limitations of harnessing PCMs in tumor therapy will be discussed.

BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment

Here, we report six novel, easily accessible BODIPY-based agents for cancer treatment. In contrast to established photodynamic therapy (PDT) agents, these BODIPY-based compounds show additional photothermal activity and their cytotoxicity is not dependent on the generation of reactive oxygen species (ROS). The agents show high photocytotoxicity upon irradiation with light and low dark toxicity in different cancer cell lines in 2D culture as well as in 3D multicellular tumor spheroids (MCTSs). The ratio of dark to light toxicity (phototoxic index, PI) of these agents reaches striking values exceeding 830,000 after irradiation with energetically low doses of light at 630 nm. The oxygen-dependent mechanism of action (MOA) of established photosensitizers (PSs) hampers effective clinical deployment of these agents. Under hypoxic conditions (0.2% O₂), which are known to limit the efficiency of conventional PSs in solid tumors, photocytotoxicity was induced at the same concentration levels, indicating an oxygen-independent photothermal MOA. With a PI exceeding 360,000 under hypoxic conditions, both PI values are the highest reported to date. We anticipate that small molecule agents with a photothermal MOA, such as the BODIPY-based compounds reported in this work, may overcome this barrier and provide a new avenue to cancer therapy.

PDT for Gastric Cancer - the view from China

The incidence rate and mortality of gastric cancer remain elevated. Traditionally, surgical treatment (including endoscopic surgery and traditional surgery), chemotherapy, targeted therapy, and immunotherapy were used for the treatment of gastric cancer. Although the emergence of targeted therapy and immunotherapy can effectively prolong the survival of some patients with gastric cancer and improve the quality of life of patients after chemotherapy or surgery, the overall survival rate of gastric cancer has not been significantly improved. Photodynamic therapy is a local photochemical therapy with the advantages of high safety, few adverse reactions, and repeatability, although it may cause some toxic reactions. There are some differences between East and West in the treatment of gastric cancer with PDT, and most earlier studies concentrated on using PDT alone. However, some studies have indicated that PDT may enhance the efficacy of chemotherapy and other medications. This paper summarizes the study on the use of PDT and its combination therapy in gastric cancer, which is anticipated to offer novel thoughts for the treatment of gastric cancer.

X-ray Activated Nanoplatforms for Deep Tissue Photodynamic Therapy

Photodynamic therapy (PDT), the use of light to excite photosensitive molecules whose electronic relaxation drives the production of highly cytotoxic reactive oxygen species (ROS), has proven an effective means of oncotherapy. However, its application has been severely constrained to superficial tissues and those readily accessed either endoscopically or laparoscopically, due to the intrinsic scattering and absorption of photons by intervening tissues. Recent advances in the design of nanoparticle-based X-ray scintillators and photosensitizers have enabled hybridization of these moieties into single nanocomposite particles. These nanoplatforms, when irradiated with diagnostic doses and energies of X-rays, produce large quantities of ROS and permit, for the first time, non-invasive deep tissue PDT of tumors with few of the therapeutic limitations or side effects of conventional PDT. In this review we examine the underlying principles and evolution of PDT: from its initial and still dominant use of light-activated, small molecule photosensitizers that passively accumulate in tumors, to its latest development of X-ray-activated, scintillator-photosensitizer hybrid nanoplatforms that actively target cancer biomarkers. Challenges and potential remedies for the clinical translation of these hybrid nanoplatforms and X-ray PDT are also presented.

Oxygen-independent alkyl radical nanogenerator enhances breast cancer therapy

The hypoxic microenvironment of breast cancer substantially reduces oxygen-dependent free radical generation. Overexpression of glutathione (GSH) in tumor cells mitigates the impact of free radical generation. In this study, we designed and developed an oxygen-independent alkyl radical nanogenerator (copper monosulfide/2,2'-azabis(2-imidazoline) dihydrochloride@bovine serum albumin; CuS/AIPH@BSA) with spatiotemporally controlled properties and GSH consumption to enhance breast cancer therapy. We encapsulated the alkyl radical initiator, AIPH, in hollow mesoporous CuS nanoparticles with photothermal conversion effect and enveloped them in BSA. AIPH was released and decomposed to generate alkyl radicals in hypoxic breast cancer with the photothermal conversion effect of CuS under near-infrared laser irradiation. CuS consumed high GSH levels in tumor cells because it could form complex with GSH and thereby enhanced free radical treatment. In vivo and in vitro assays demonstrated the anti-tumor efficacy of the rationally designed free-radical nanogenerator in hypoxic microenvironment of breast cancer without showing systemic toxicity.

Chitosan Composites Containing Boron-Dipyrromethene Derivatives for Biomedical Applications

The work is devoted to preparing and characterizing the properties of photosensitive composites, based on chitosan proposed for photodynamic therapy. Chitosan films with a 5% addition of two BODIPY dyes were prepared by solution casting. These dyes are dipyrromethene boron derivatives with N-alkyl phthalimide substituent, differing in the presence of iodine atoms in positions 2 and 6 of the BODIPY core. The spectral properties of the obtained materials have been studied by infrared and UV-vis absorption spectroscopy and fluorescence, both in solutions and in a solid state. Surface properties were investigated using the contact angle measurement. The morphology of the sample has been characterized by Scanning Electron and Atomic Force Microscopy. Particular attention was paid to studying the protein absorption and kinetics of the dye release from the chitosan. Adding BODIPY to the chitosan matrix leads to a slight increase in hydrophilicity, higher structure heterogeneity, and roughness, than pure chitosan. The presence of iodine atoms in the BODIPY structure caused the bathochromic effect, but the emission quantum yield decreased in the composites. It has been found that BODIPY-doped chitosan interacts better with human serum albumin and acidic α-glycoprotein than unmodified chitosan. The release rate of dyes from films immersed in methanol depends on the iodine present in the structure.

Advancements in nanoparticle-based treatment approaches for skin cancer therapy

Skin cancer has emerged as the fifth most commonly reported cancer in the world, causing a burden on global health and the economy. The enormously rising environmental changes, industrialization, and genetic modification have further exacerbated skin cancer statistics. Current treatment modalities such as surgery, radiotherapy, conventional chemotherapy, targeted therapy, and immunotherapy are facing several issues related to cost, toxicity, and bioavailability thereby leading to declined anti-skin cancer therapeutic efficacy and poor patient compliance. In the context of overcoming this limitation, several nanotechnological advancements have been witnessed so far. Among various nanomaterials, nanoparticles have endowed exorbitant advantages by acting as both therapeutic agents and drug carriers for the remarkable treatment of skin cancer. The small size and large surface area to volume ratio of nanoparticles escalate the skin tumor uptake through their leaky vasculature resulting in enhanced therapeutic efficacy. In this context, the present review provides up to date information about different types and pathology of skin cancer, followed by their current treatment modalities and associated drawbacks. Furthermore, it meticulously discusses the role of numerous inorganic, polymer, and lipid-based nanoparticles in skin cancer therapy with subsequent descriptions of their patents and clinical trials.

Anti-tumor immunity enhancement by photodynamic therapy with talaporfin sodium and anti-programmed death 1 antibody

Photodynamic therapy (PDT) is a relatively non-invasive anti-cancer therapy that employs a photosensitizer with a specific wavelength of light irradiation. PDT induces direct cell killing and enhancement effects on tumor immunity, but its underlying mechanism remains unknown. Here, we perform a basic analysis of the anti-tumor effect of talaporfin sodium (TS)-PDT as well as its synergism with the immune checkpoint inhibitor anti-programmed death 1 (anti-PD-1) antibody. We estimate the cell death mechanism induced by TS-PDT and the induction of damage-associated molecular patterns (DAMPs) by TS-PDT in vitro. We establish a syngeneic mouse model of bilateral flank tumors and verify the enhancement of the abscopal effect on the non-irradiated side. TS-PDT induced apoptosis, necrosis, and autophagy-associated cell death in vitro. TS-PDT induced the release and/or expression of DAMPs in vitro. Tumor growth was inhibited in the TS-PDT and anti-PD-1 antibody combination group compared with other single-treatment or non-treatment groups in vivo. In summary, TS-PDT induces the release and/or expression of DAMPs, indicating that it activates innate immunity. PD-1 blockage enhances the anti-tumor immunity induced by TS-PDT. Thus, our results demonstrate that the combination of TS-PDT and anti-PD-1 antibody can potentially be used for anti-tumor therapy.

Enhanced Photodynamic Therapy: A Review of Combined Energy Sources

Photodynamic therapy (PDT) has been used in recent years as a non-invasive treatment for cancer, due to the side effects of traditional treatments such as surgery, radiotherapy, and chemotherapy. This therapeutic technique requires a photosensitizer, light energy, and oxygen to produce reactive oxygen species (ROS) which mediate cellular toxicity. PDT is a useful non-invasive therapy for cancer treatment, but it has some limitations that need to be overcome, such as low-light-penetration depths, non-targeting photosensitizers, and tumor hypoxia. This review focuses on the latest innovative strategies based on the synergistic use of other energy sources, such as non-visible radiation of the electromagnetic spectrum (microwaves, infrared, and X-rays), ultrasound, and electric/magnetic fields, to overcome PDT limitations and enhance the therapeutic effect of PDT. The main principles, mechanisms, and crucial elements of PDT are also addressed.

Photodynamic Therapy for Colorectal Cancer: A Systematic Review of Clinical Research

BACKGROUND

Photodynamic therapy (PDT) is a therapeutic modality that can be used to ablate tumors using the localized generation of reactive oxygen species by combining a photosensitizer, light, and molecular oxygen. This modality holds promise as an adjunctive therapy in the management of colorectal cancer and could be incorporated into neoadjuvant treatment plans under the auspices of prospective clinical trials.

METHODS

We conducted a search of primary literature published until January 2021, based on PRISMA guidelines. Primary clinical studies of PDT for the management of colorectal cancer were included. Screening, inclusion, quality assessment, and data collection were performed in duplicate. Analyses were descriptive or thematic.

RESULTS

Nineteen studies were included, most of which were case series. The total number of patients reported to have received PDT for colorectal cancer was 137, almost all of whom received PDT with palliative intent. The most common photosensitizer was hematoporphyin derivative or Photofrin. The light dose used varied from 32 J/cm² to 500 J/cm². Complete tumor response (cure) was reported in 40%, with partial response reported in 43.2%. Symptomatic improvement was reported in 51.9% of patients. In total, 32 complications were reported, the most common of which was a skin photosensitivity reaction.

CONCLUSIONS

PDT for the management of colorectal cancer has not been well studied, despite promising results in early clinical case series. New, well designed, prospective clinical trials are required to establish and define the role of PDT in the management of colorectal cancer.

Advanced techniques for performing photodynamic therapy in deep-seated tissues

Photodynamic therapy (PDT) is a promising localized cancer treatment modality. It has been used successfully to treat a range of dermatological conditions with comparable efficacy to conventional treatments. However, some drawbacks limit the clinical utility of PDT in treating deep-seated tumors. Notably, the penetration limitation of UV and visible light, commonly applied to activate photosensitizers, makes PDT incompetent in treating deep-seated tumors. Development in light delivery technologies, especially fiber optics, led to improved clinical strategies for accessing deep tissues for irradiation. However, PDT efficacy issues remained partly due to light penetration limitations. In this review, we first summarized the current PDT applications for deep-seated tumor treatment. Then, the most recent progress in advanced techniques to overcome the light penetration limitation in PDT, including using functional nanomaterials that can either self-illuminate or be activated by near-infrared (NIR) light and X-rays as transducers, and implantable light delivery devices were discussed. Finally, current challenges and future opportunities of these technologies were discussed, which we hope may inspire the development of more effective techniques to enhance PDT efficacy against deep-seated tumors.

Cancer therapy by antibody-targeted Cerenkov light and metabolism-selective photosensitization

Photodynamic therapy (PDT) is an effective cancer treatment option, but it suffers from penetration limit of light, making it available only for superficial and endoscopically accessible cancers. Recently, there have been reports that Cerenkov luminescence originated from radioisotopes can be utilized as an excitation source for PDT without external light illumination. Here, cancer-selective agents, i.e., (1) clinically available 5-aminolevulinic acid (5-ALA), which promotes cancer metabolism-specific accumulation of protoporphyrin IX (PpIX), and (2) ⁶⁴Cu-DOTA-trastuzumab, which has HER2-expressing cancer selective uptake, are separately applied as a photosensitizer and an in situ radiator, respectively, to potentiate tumor-specific Cerenkov luminescence energy transfer (CLET) from ⁶⁴Cu to PpIX for high-precision PDT of cancer. It is shown that the combinational administration and tumor colocalization of 5-ALA and ⁶⁴Cu-DOTA-trastuzumab exert significant in vitro cytotoxicity (cell viability <9%) as well as in vivo antitumor effects (tumor volume ratio of 0.50 on 14 days post-injection) on HER2-expressing breast and gastric cancer models. This study proves that high-precision treatment regimen using dual-targeted CLET-based PDT is feasible for HER2-expressing cancers. Furthermore, the results offer great potential for clinical translation to the dual-targeted CLET-based PDT because the treatment regimen uses components, 5-ALA and ⁶⁴Cu-DOTA-trastuzumab, which are already in clinical uses.

An open-source LED array illumination system for automated multiwell plate cell culture photodynamic therapy experiments

Photodynamic therapy (PDT) research would benefit from an automated, low-cost, and easy-to-use cell culture light treatment setup capable of illuminating multiple well replicates within standard multiwell plate formats. We present an LED-array suitable for performing high-throughput cell culture PDT experiments. The setup features a water-cooling loop to keep the LED-array temperature nearly constant, thus stabilizing the output power and spectrum. The setup also features two custom-made actuator arms, in combination with a pulse-width-modulation (PWM) technique, to achieve programmable and automatic light exposures for PDT. The setup operates at ~ 690 nm (676-702 nm, spectral output full-width half-maximum) and the array module can be readily adapted to other LED wavelengths. This system provides an illumination field with adjustable irradiance up to 400 mW/cm² with relatively high spectral and power stability comparing with previously reported LED-based setups. The light doses provided by the LED array were validated with comparison to traditional laser PDT. This open-source illumination platform (including the detailed technical description, fabrication protocols, and parts list provided here) helps to make custom light sources more accessible and of practical use for photomedicine research.

Nanophotosensitizers Composed of Phenyl Boronic Acid Pinacol Ester-Conjugated Chitosan Oligosaccharide via Thioketal Linker for Reactive Oxygen Species-Sensitive Delivery of Chlorin e6 against Oral Cancer Cells

Chlorin E6 (Ce6)-incorporated nanophotosensitizers were fabricated for application in photodynamic therapy (PDT) of oral cancer cells. For this purpose, chitosan oligosaccharide (COS) was conjugated with hydrophobic and reactive oxygen species (ROS)-sensitive moieties, such as phenyl boronic acid pinacol ester (PBAP) via a thioketal linker (COSthPBAP). ThdCOOH was conjugated with PBAP to produce ThdCOOH-PBAP conjugates and then attached to amine groups of COS to produce a COSthPBAP copolymer. Ce6-incorporated nanophotosensitizers using the COSthPBAP copolymer were fabricated through the nanoprecipitation and dialysis methods. The Ce6-incorporated COSthPBAP nanophotosensitizers had a small diameter of less than 200 nm with a mono-modal distribution pattern. However, it became a multimodal and/or irregular distribution pattern when H₂O₂ was added. In a morphological observation using TEM, the nanophotosensitizers were disintegrated by the addition of H₂O₂, indicating that the COSthPBAP nanophotosensitizers had ROS sensitivity. In addition, the Ce6 release rate from the COSthPBAP nanophotosensitizers accelerated in the presence of H₂O₂. The SO generation was also higher in the nanophotosensitizers than in the free Ce6. Furthermore, the COSthPBAP nanophotosensitizers showed a higher intracellular Ce6 uptake ratio and ROS generation in all types of oral cancer cells. They efficiently inhibited the viability of oral cancer cells under light irradiation, but they did not significantly affect the viability of either normal cells or cancer cells in the absence of light irradiation. The COSthPBAP nanophotosensitizers showed a tumor-specific delivery capacity and fluorescence imaging of KB tumors in an in vivo animal tumor imaging study. We suggest that COSthPBAP nanophotosensitizers are promising candidates for the imaging and treatment of oral cancers.

The response of the canine mammary simple carcinoma and carcinosarcoma cells to 5-aminolaevulinic acid-based photodynamic therapy: An in vitro study

BACKGROUNDS

Canine mammary gland tumors (CMGTs) are heterogeneous tumors and share many similar features with human breast cancer. Despite the improvement of current treatment options, new treatment modalities are required to effectively kill tumor cells without general toxicity in the treatment of CMGTs. Photodynamic therapy (PDT) is a promising method for cancer treatment. However, there is a limited study evaluating the therapeutic efficacy of PDT in the treatment of CMGTs.

METHODS

In this context, we, for the first time, investigated the therapeutic potential of 5-aminolaevulinic acid (5-ALA) mediated PDT at 6 and 12 J/cm² in two different subtypes [Tubulopapillary carcinoma (TPC) and carcinosarcoma (CS)] cells via different molecular analysis. The cytotoxic effects of 5-ALA/PDT on these cells were analyzed by intracellular PpIX level, WST-1 and ROS analysis. Furthermore, the underlying moleculer mechanism of 5-ALA/PDT mediated apoptotic effects on TPC and CS cells were evaluated Annexin V, AO/PI, RT-PCR and western blot analysis.

RESULTS

The 5-ALA/PDT treatment upon irradiation considerably inhibited the viability of both TPC and CS cells (p<0.01) and caused apoptotic death through elevated ROS levels, the activation of Caspase-9, and Caspase-3, and the overexpression of Bax. However, the response of TPC and CS cells to 5-ALA/PDT was different.

CONCLUSIONS

Our preliminary in vitro findings provide novel insights into the molecular mechanisms underlying 5-ALA/PDT mediated apoptosis in both TPC and CS cells. However, the therapeutic response of CMGT cells to 5-ALA/PDT is limited.

Fluorescence kinetics study of twice laser irradiation based HpD-PDT for nonmelanoma skin cancer

BACKGROUND

Hematoporphyrine injection (HpD)-based photodynamic therapy (HpD-PDT) has emerged as a promising cancer therapy. However, its tumor-targeting ability and metabolokinetics in nonmelanoma skin cancer (NMSC) have not been well explored. Importantly, photodynamic diagnosis is widely used for cancer lesion assessment and positioning to ensure effective therapy, while the photosensitizer metabolic kinetics study is utilized for biosafety assessment and light-protection instruction. These are particularly important for the optimization of therapeutic parameters.

OBJECTIVES

In the present study, NMSC patients were subjected to twice laser irradiation-based HpD-PDT strategy. Broadly, the study aimed to assess long-term variations in fluorescence (FL) intensity in vivo in NMSC patients after intravenous (i.v.) administration of HpD, and thus obtain information regarding metabolism, biosafety, and light-protection instruction for HpD during the therapy.

METHODS

In vitro experiments were used for the evaluation of absorption and fluorescent characterization of HpD in aqueous solution and cutaneous squamous cell carcinoma (SCC) cells. For in vivo assessment, 20 patients with NMSC, including SCC, basal cell carcinoma (BCC), Bowen disease (BD), extramammary Paget's disease (EMPD), and malignant proliferating tricholemmoma (APT), were recruited, and treated with HpD-PDT. To evaluate the selectivity and pharmacokinetics of HpD in vivo, relative changes in FL intensity for lesional, perilesional, and nonlesional skin of nonmelanoma skin cancer patients, before and after HpD injection, were semiquantitatively analyzed for 1 month, using the FL detection system and Wood's lamp.

RESULTS

The absorption and FL spectra were detected and semiquantitatively analyzed in HpD diluted solution and SCC cells after coincubation with HpD. After i.v. administration of HpD in EMPD patients, FL was detected in the skin lesions at 24 hours, and it was characterized by clear edges. Importantly, FL intensity in the skin lesions increased significantly at 48 and 72 hours postinjection, which was suitable for HpD-PDT. After 72 h, it decreased gradually and reached close to the baseline value at 4 weeks postinjection. No severe side effects were observed during HpD injection and the therapy. Urinary tract infection was recorded in one patient (with a previous history of recurrent urinary tract infections) after HpD-PDT, and the patient was cured afterward. Transient light was observed in two patients after HpD-PDT and they soon recovered after therapy.

CONCLUSIONS

The present study reported a significant increase in FL intensities at 48 and 72 hours after i.v. administration of HpD in patients with nonmelanoma skin cancers, which indicated accumulation of HpD at the cancer site. Importantly, HpD was found to be safe for NMSC patients. After therapy, FL intensities decreased, which indicated expending and metabolization of HpD. Thus, the results of the present study highlighted the suitability of a twice red-light laser irradiation strategy for the application of HpD-PDT in nonmelanoma skin cancer treatment.

Fundamentals and applications of metal nanoparticle- enhanced singlet oxygen generation for improved cancer photodynamic therapy

The introduction of nanotechnology in the field of Photodynamic Therapy (PDT) has proven to have great potential to overcome some of the challenges associated with traditional organic photosensitizers (PS) with respect to their solubility, drug delivery, distribution and site-specific targeting. Other focused areas in PDT involve high singlet oxygen production capability and excitability of PS by deep tissue penetrating light wavelengths. Owing to their very promising optical and surface plasmon resonance properties, combination of traditional PSs with plasmonic metallic nanoparticles like gold and silver nanoparticles results in remarkably high singlet oxygen production and extended excitation property from visible and near-infrared lights. This review summarizes the importance, fundamentals and applications of on plasmonic metallic nanoparticles in PDT. Lastly, we highlight the future prospects of these plasmonic nanoengineering strategies with or without PS combination, to have a significant impact in improving the therapeutic efficacy of cancer PDT.

Photodynamic therapy with 5-aminolevulinic acid: A new diagnostic, therapeutic, and surgical aid for neuroblastoma

BACKGROUND

5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) is widely used in cancer therapy because of the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX). We aimed to assess the susceptibility of human neuroblastoma cell lines to ALA-PDT and determine the mechanism of PDT.

METHODS

We used four human neuroblastoma cell lines (GOTO, NB9, IMR32, and NB1) and a gastric cancer cell line (MKN45) as a positive control. Cells were treated with increasing concentrations of ALA, and the ALA-induced production of PpIX in tumor cells was quantified using fluorescence spectrophotometry. PDT photocytotoxicity was measured by exposing the cells to a 630-nm irradiation for 10 min, and apoptotic cells stained with phosphatidylserine (PS) and propidium iodide (PI) were detected through flow cytometry.

RESULTS

ALA cytotoxicity was not observed in any cell line. The intracellular concentration of PpIX increased in an ALA dose-dependent manner, and intracellular fluorescence of PpIX increased in a time-dependent manner. The viability of NB-1 cells treated with 250 μM 5-ALA rapidly decreased to 5%. Photocytotoxicity was observed in the following order: NB1, IMR32, NB-9, and GOTO. Photocytotoxicity was positively correlated with intracellular PpIX concentrations. PS+/PI- cells increased up to 21% after 12 h, and PS+/PI+ cells accounted for 35% of all cells after 24 h, which suggests that ALA-PDT induced apoptotic cell death.

CONCLUSION

This study shows that neuroblastoma cell lines were susceptible to 5-ALA-PDT, resulting in persistent apoptotic cell death.

LEVELS OF EVIDENCE

N/A for basic study.

Comparative analysis of Radachlorin accumulation, localization, and photobleaching in three cell lines by means of holographic and fluorescence microscopy

In this paper we compare the response of cells of established lines of different origin: HeLa, A549 and 3T3 to photodynamic treatment with Radachlorin photosensitizer. The analysis was performed on different aspects of the treatment procedure including photosensitizer accumulation, localization and photobleaching in cells and post-treatment dynamics of changes in cellular morphology at different treatment doses. It was shown that in the three cell lines Radachlorin accumulated in lysosomes to much greater extent than in mitochondria. The cells' response to treatment was analyzed by identification of their death pathways and evaluation of average phase shift dynamics using digital holographic microscopy. The analysis performed on the three cell lines allowed us to evaluate treatment doses specific for each pathway in each line. Among the three lines HeLa cells were found to be the most susceptible to treatment while 3T3 cells the most resistant. The comparison of these results with the data on Radachlorin accumulation, localization and photobleaching rates showed that the observed higher sensitivity of HeLa cells to photodynamic treatment correlated with higher photosensitizer uptake and more intensive photobleaching while lower sensitivity of 3T3 cells correlated with lower uptake and less intensive photobleaching.

Synthesis of near-infrared-responsive hexagonal-phase upconversion nanoparticles with controllable shape and luminescence efficiency for theranostic applications

Over the past few decades, photodynamic therapy has been studied as a therapeutic method by generating singlet oxygen through activation of a photosensitizer (PS) to kill cancer cells. However, the light within the activating wavelength range of commercial photosensitizers has a low penetration depth. In this study, we designed multifunctional upconversion nanoparticles (UCNs) that can emit high-energy light by absorbing low-energy near-infrared (NIR) light with excellent tissue permeability through a fluorescence resonance energy transfer procedure. This process can produce reactive oxygen species by activating the PS. We aimed to optimize the thermal decomposition synthesis procedure to produce lanthanide-doped UCNs with a uniform size and improve the photoluminescence efficiency for an NIR-regulated theranostic system. It was confirmed that the morphologies of UCNs can be controlled by varying the reaction time, reaction temperature, and feed molar ratio of the solvent and reactant. The crystalline morphology of the synthesized UCNs showed a thermodynamically stable hexagonal phase. The photoluminescence efficiency of the UCNs also was influenced by size, surface area, crystalline property, and stability in aqueous solution. Furthermore, the surface-modified UCNs with a folic acid-conjugated block copolymer and PS exhibited enhanced singlet oxygen generation and significantly improved aqueous solubility and photoluminescence efficiency.

Gold nanomaterials for oral cancer diagnosis and therapy: Advances, challenges, and prospects

Early diagnosis and treatment of oral cancer are vital for patient survival. Since the oral cavity accommodates the second largest and most diverse microbiome community after the gut, the diagnostic and therapeutic approaches with low invasiveness and minimal damage to surrounding tissues are keys to preventing clinical intervention-related infections. Gold nanoparticles (AuNPs) are widely used in the research of cancer diagnosis and therapy due to their excellent properties such as surface-enhanced Raman spectroscopy, surface plasma resonance, controlled synthesis, the plasticity of surface morphology, biological safety, and stability. AuNPs had been used in oral cancer detection reagents, tumor-targeted therapy, photothermal therapy, photodynamic therapy, and other combination therapies for oral cancer. AuNPs-based noninvasive diagnosis and precise treatments further reduce the clinical intervention-related infections. This review is focused on the recent advances in research and application of AuNPs for early screening, diagnostic typing, drug delivery, photothermal therapy, radiotherapy sensitivity treatment, and combination therapy of oral cancer. Distinctive reports from the literature are summarized to highlight the latest advances in the development and application of AuNPs in oral cancer diagnosis and therapy. Finally, this review points out the challenges and prospects of possible applications of AuNPs in oral cancer diagnosis and therapy.

Nanoparticle-based therapeutic strategies targeting major clinical challenges in pancreatic cancer treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers due to its aggressiveness and the challenges for early diagnosis and treatment. Recently, nanotechnology has demonstrated relevant strategies to overcome some of the major clinical issues in the treatment of PDAC. This review is focused on the pathological hallmarks of PDAC and the impact of nanotechnology to find solutions. It describes the use of nanoparticle-based systems designed for the delivery of chemotherapeutic agents and combinatorial alternatives that address the chemoresistance associated with PDAC, the development of combination therapies targeting the molecular heterogeneity in PDAC, the investigation of novel therapies dealing with the improvement of immunotherapy and handling the desmoplastic stroma in PDAC by remodeling the tumor microenvironment. A special section is dedicated to the design of nanoparticles for unique non-traditional modalities that could be promising in the future for the improvement in the dismal prognosis of PDAC.

Assessment of the methylene blue mediated photodynamic therapy on BCL2 and BAX genes expression at mRNA level and apoptosis of head and neck squamous cell carcinoma cell line

Aim: This study aimed to assess the effect of photodynamic therapy (PDT) on apoptosis of head and neck squamous cell carcinoma (HNSCC) cells by flow cytometry and evaluating BAX and BCL2 genes expression.

Materials and methods: In this in vitro study, human HNSCC cell line (HN5; NCBI. C196) was used and after cell culture, they were divided into four groups: controls (group C), cells irradiated by a diode laser with a wavelength of 660 nm, 150 mW power, and 45 J/cm2 energy density (group L), cells treated by methylene blue (group MB), and cells treated using PDT (group MB plus L). The RNA was then extracted and subjected to quantitative reverse transcription polymerase chain reaction (qRT-PCR) to assess BCL2 and BAX genes expression. Flow cytometry analysis was performed to assess apoptosis. Data were analysed using ANOVA.

Results: PDT caused significant down-regulation of BCL2 (p&lt;0.001) and significant overexpression of BAX (p&lt;0.05) and PDT induced apoptosis HNSCC cell line. Changes in expression of these genes were not significant in other groups (p&gt;0.05).

Conclusions: Considering the down-regulation of BCL2 and overexpression of BAX after PDT using a 660-nm diode laser and MB with 3.2 µg/mL concentration and flow cytometry results, it is suggested that this modality can be introduced for induction of apoptosis in the HNSCC cell line.

Combination of Curcumin and Photodynamic Therapy Based on the Use of Red Light or Near-Infrared Radiation in Cancer: a Systematic Review

BACKGROUND

Photodynamic therapy (PDT) is a therapeutic intervention that can be applied to the treatment of cancer. The interaction between a photosensitizer (PS), ideal wavelength radiation and tissue molecular oxygen, triggers a series of photochemical reactions that are responsible for the production of reactive oxygen species. These highly reactive species can decrease proliferation and induce tumor cell death. The search for PS of natural origin extracted from plants becomes relevant, as they have photoactivation capacity, preferentially targeting tumor cells and because they do not present any or little toxicity to healthy cells.

OBJECTIVE

Our work aimed to carry out a qualitative systematic review to investigate the effects of curcumin (CUR), a molecule considered as PS of natural origin, on PDT, using red light or near infrared radiation, in tumor models.

METHODS

A systematic search was performed in three databases (PubMed, Scopus, and Web of Science) using the PICOT method, retrieving a total of 1,373 occurrences. At the end of the peer screening, using inclusion, exclusion, and eligibility criteria, 25 eligible articles were included in this systematic review.

RESULTS

CUR, whether in its free state, associated with metal complexes or other PS, and in a nanocarrier system, was considered a relevant PS for PDT using red light or near-infrared against tumoral models in vitro and in vivo, acting by increasing cytotoxicity, inhibiting proliferation, inducing cell death mainly by apoptosis, and changing oxidative parameters.

CONCLUSION

The results found in this systematic review suggest the potential use of CUR as a PS of natural origin to be applied in PDT against many neoplasms, encouraging further search in the field of PDT against cancer and serving as an investigative basis for upcoming pre-clinical and clinical applications.

Recent advances in ZnO-based photosensitizers: Synthesis, modification, and applications in photodynamic cancer therapy

Zinc oxide nanoparticles (ZnO NPs) are important semiconductor materials with interesting photo-responsive properties. During the past, ZnO-based NPs have received considerable attention for photodynamic therapy (PDT) due to their biocompatibility and excellent potential of generating tumor-killing reactive oxygen species (ROS) through gentle photodynamic activation. This article provides a comprehensive review of the recent developments and improvements in optical properties of ZnO NPs as photosensitizers for PDT. The optical properties of ZnO-based photosensitizers are significantly dependent on their charge separation, absorption potential, band gap engineering, and surface area, which can be adjusted/tuned by doping, compositing, and morphology control. Here, we first summarize the recent progress in the charge separation capability, absorption potential, band gap engineering, and surface area of nanosized ZnO-based photosensitizers. Then, morphology control that is closely related to their synthesis method is discussed. Following on, the state-of-art for the ZnO-based NPs in the treatment of hypoxic tumors is comprehensively reviewed. Finally, we provide some outlooks on common targeted therapy methods for more effective tumor killing, including the attachment of small molecules, antibodies, ligands molecules, and receptors to NPs which further improve their selective distribution and targeting, hence improving the therapeutic effectiveness. The current review may provide useful guidance for the researchers who are interested in this promising dynamic cancer treatment technology.