Photodynamic Therapy Treatment Research Articles

Photodynamic therapy in treatment of squamous cell carcinoma of oral cavity with chlorine e6 photosensitizer with long-term follow up

Photodynamic therapy in treatment of squamous cell carcinoma of oral cavity with chlorine e6 photosensitizer with long-term follow up

Biocompatible Copper-Based Nanocomposites for Combined Cancer Therapy.

Copper (Cu) and Cu-based nanomaterials have received tremendous attention in recent years because of their unique physicochemical properties and good biocompatibility in the treatment of various diseases, especially cancer. To date, researchers have designed and fabricated a variety of integrated Cu-based nanocomplexes with distinctive nanostructures and applied them in cancer therapy, mainly including chemotherapy, radiotherapy (RT), photothermal therapy (PTT), chemodynamic therapy (CDT), photodynamic therapy (PDT), cuproptosis-mediated therapy, etc. Due to the limited effect of a single treatment method, the development of composite diagnostic nanosystems that integrate chemotherapy, PTT, CDT, PDT, and other treatments is of great significance and offers great potential for the development of the next generation of anticancer nanomedicines. In view of the rapid development of Cu-based nanocomplexes in the field of cancer therapy, this review focuses on the current state of research on Cu-based nanomaterials, followed by a discussion of Cu-based nanocomplexes for combined cancer therapy. Moreover, the current challenges and future prospects of Cu-based nanocomplexes in clinical translation are proposed to provide some insights into the design of integrated Cu-based nanotherapeutic platforms.

Minimally Invasive Semiconductor Laser Surgery Combined with 5-ALA Photodynamic Therapy for a Chronic Hyperplastic Candidiasis Patient Who Is Ineffective to Antifungal Therapy.

Background: Chronic hyperplastic candidiasis (CHC) is a chronic oral mucosal infection caused by Candida, which has potential for malignant transformation. Diagnosing CHC can be challenging due to its various manifestations. In addition, fungal treatments often prove to be ineffective, highlighting the urgent need for a new safe and efficient treatment approach. Given the potential of CHC to transform into malignancy, it is crucial to emphasize dynamic monitoring and follow-up after treatment. Objective: We attempted to investigate the effect of semiconductor laser pretreatment combined with 5-amino-levulinic acid (5-ALA) photodynamic therapy (PDT) for CHC. Methods: We presented the successful treatment of CHC with mild dysplasia in a 30-year-old man using semiconductor laser and 5-ALA PDT after antifungal therapy proved ineffective. Toluidine blue staining, autofluorescence imaging, and DNA image cytometry were combined to dynamically monitor the progress of the disease. Results: We have obtained positive outcomes with the use of laser combined with PDT treatment. The patients experienced only mild adverse reactions after the treatment, and there was no indication of recurrence or malignant transformation during the subsequent follow-up period, as observed through various auxiliary examinations. Conclusions: This case report suggests that semiconductor laser surgery combined with PDT could be a promising treatment option for patients with CHC who do not respond to antifungal therapy. In addition, the use of combined noninvasive examinations might provide a more accurate assessment of malignant transformation in patients with CHC.

Programmable activation of berbamine and photosensitizers for enhanced photodynamic therapy using emission-switchable upconversion nanoparticles

Photodynamic therapy (PDT) shows great potential in precision tumor treatment. However, its efficacy is inhibited by the antioxidant defense capacities of tumor cells. To address this challenge, a near-infrared light-controlled nanosystem (UCNPs@mSiO2@Azo@ZnPc&BBM, PB@UA) was developed using emission-switchable upconversion nanoparticles (UCNPs) to independently and precisely control the release of berbamine (BBM) and activation of photosensitizer for enhanced PDT in deep tissues. Firstly, BBM release was triggered by exciting PB@UA at 980 nm. The BBM could inhibit the activities of antioxidant enzymes and disrupt calcium ion regulation, making the tumor cells more susceptible to ROS-induced cell death in the following PDT treatment. The PDT was initiated by irradiating the photosensitizers of ZnPc on PB@UA at 808 nm and achieved a tumor inhibition rate of 80.91 % in vivo, which is significantly higher than that of unique PDT (31.78 %) or BBM (11.29 %) treatment and demonstrates the potential of our strategy for improved cancer treatment.

Combined Ferritin Nanocarriers with ICG for Effective Phototherapy Against Breast Cancer.

Photodynamic Therapy (PDT) is a promising, minimally invasive treatment for cancer with high immunostimulatory potential, no reported drug resistance, and reduced side effects. Indocyanine Green (ICG) has been used as a photosensitizer (PS) for PDT, although its poor stability and low tumor-target specificity strongly limit its efficacy. To overcome these limitations, ICG can be formulated as a tumor-targeting nanoparticle (NP). We nanoformulated ICG into recombinant heavy-ferritin nanocages (HFn-ICG). HFn has a specific interaction with transferrin receptor 1 (TfR1), which is overexpressed in most tumors, thus increasing HFn tumor tropism. First, we tested the properties of HFn-ICG as a PS upon irradiation with a continuous-wave diode laser. Then, we evaluated PDT efficacy in two breast cancer (BC) cell lines with different TfR1 expression levels. Finally, we measured the levels of intracellular endogenous heavy ferritin (H-Fn) after PDT treatment. In fact, it is known that cells undergoing ROS-induced autophagy, as in PDT, tend to increase their ferritin levels as a defence mechanism. By measuring intracellular H-Fn, we verified whether this interplay between internalized HFn and endogenous H-Fn could be used to maximize HFn uptake and PDT efficacy. We previously demonstrated that HFn-ICG stabilized ICG molecules and increased their delivery to the target site in vitro and in vivo for fluorescence guided surgery. Here, with the aim of using HFn-ICG for PDT, we showed that HFn-ICG improved treatment efficacy in BC cells, depending on their TfR1 expression. Our data revealed that endogenous H-Fn levels were increased after PDT treatment, suggesting that this defence reaction against oxidative stress could be used to enhance HFn-ICG uptake in cells, increasing treatment efficacy. The strong PDT efficacy and peculiar Trojan horse-like mechanism, that we revealed for the first time in literature, confirmed the promising application of HFn-ICG in PDT.

Chlorin Conjugates in Photodynamic Chemotherapy for Triple-Negative Breast Cancer

Breast cancer (BC) is the most common type of cancer in women and the number of new cases in the US is still increasing each year. Triple-negative breast cancer (TNBC), which comprises 15–20% of all breast cancer, is a heterogeneous disease and is considered the most aggressive type of breast cancer due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions for treatments. Traditional chemotherapy is the standard protocol for the treatment of TNBC. Toxicity and multidrug resistance are major drawbacks to chemotherapy. The lack of molecular targets and poor prognosis for TNBC prompts an urgent need to discover novel therapeutic strategies to improve clinical outcomes and quality of life for patients. Photodynamic therapy (PDT) or light treatment is a binary anti-cancer procedure that uses a photosensitizer (PS) that, upon light activation, produces cytotoxic oxygen species, destroying tumor cells. PDT is minimally invasive and can be repeated a few times without accumulating significant toxicity in the surrounding tissues. The primary goal of this study was to investigate in vitro photodynamic chemotherapy as a ternary combination therapy using our synthesized photosensitizers (chlorin–vitamin conjugates and their corresponding indium complexes) co-treated with known chemotherapeutic agents (taxol, doxorubicin, cisplatin, fluorouracil, or methotrexate) in the presence of light and determine the optimum conditions as a pre-clinical study of an enhanced tumoricidal effect against TNBC. Our results indicated that the best combination for an effective chemophotodynamic effect involves a ternary treatment of the indium complex of the chlorin–lipoic acid conjugate (InCLA) co-treated with taxol, which exhibited strong synergism at the nanomolar concentration when combined in the presence of visible light irradiation. Other ternary combinations containing taxol with a synergistic anti-tumor effect against TNBC include chlorin–pantothenic acid (CPA) and chlorin–biotin (CBTN) conjugates. Several other ternary combinations containing InCLA, CBTN, and CPA with either cisplatin, fluorouracil, or methotrexate were identified to generate a synergistic or additive effect. The light dosage remained constant, but the dosages of photosensitizers and chemotherapy drugs were varied to obtain the lowest possible concentration for the desired effect. The synergistic, additive or antagonistic effects of the drug combinations were determined based on the Chou–Talalay method, with InCLA–taxol having the lowest combination index (CI) of 0.25. Fluorescence and transmission electron microscopy (TEM) images provided evidence of apoptosis as the preferred mode of cell death. Our study demonstrated the combination of PDT and chemotherapy as a potential treatment option for TNBC patients.

The orthogonal α‐meso‐Linked bisBODIPY photosensitizers demonstrate effective two‐photon fluorescence imaging and photodynamic therapy

Hypoxic tumor microenvironments pose significant challenges to the clinical translation of cancer photodynamic therapy (PDT). While heavy atom‐free Type‐I boron dipyrromethenes (BODIPYs) photosensitizers can alleviate this challenge by reducing oxygen dependency, but they remain scarce. Herein, heavy‐atom‐free α,meso‐linked bisBODIPYs were designed and synthesized. These bisBODIPYs exhibit remarkable red‐shifted emission (λemmax ~670 nm), large Stokes shifts (~4480 cm‐1) and they are capable of producing both superoxide anion (O2•−) and singlet oxygen (1O2) in solution and cells. Additionally, they offer a wide PDT treatment window, ranging from 0.26 to 83.5 μM. Furthermore, these bisBODIPYs also demonstrate superior two‐photon fluorescence, promising for surgical navigation and integrating diagnosis with treatment.

First-principles design of heavy-atom-free singlet oxygen photosensitizers for photodynamic therapy.

In photodynamic therapy (PDT) treatment, heavy-atom-free photosensitizers (PSs) are a great source of singlet oxygen photosensitizer. Reactive oxygen species (ROS) are produced by an energy transfer from the lowest energy triplet excited state to the molecular oxygen of cancer cells. To clarify the photophysical characteristics in the excited states of a few experimentally identified thionated (>C=S) molecules and their oxygenated congeners (>C=O), a quantum chemical study is conducted. This study illustrates the properties of the excited states in oxygen congeners that render them unsuitable for PDT treatment. Concurrently, a hierarchy is presented based on the utility of the lowest-energy triplet excitons of thionated compounds. Their non-radiative decay rates are calculated for reverse-ISC and inter-system crossover (ISC) processes. In addition, the vibronic importance of C=O and C=S bonds is clarified by the computation of the Huang-Rhys factor, effective vibrational mode, and reorganization energy inside the Marcus-Levich-Jörtner system. ROS generation in thionated PSs exceeds their oxygen congeners as kf ≪ kISC, where radiative decay rate is designated as kf. As a result, the current work offers a calculated strategy for analyzing the effectiveness of thionated photosensitizers in PDT.

Anticancer photodynamic activities of triphenylphosphine-labelled phthalocyanines and their bovine serum albumin-gold nanoparticles- complexes on melanoma A375 cell lines in vitro

This work reports on the synthesis of triphenylphosphine-labelled cationic phthalocyanines (Pc) complexed with bovine serum albumin (BSA) and gold nanoparticles (Au NPs). This nano-complex (Pc-BSA-Au) is studied for its photodynamic therapy (PDT) activity compared to the non-complexed Pc counterpart. The photochemical properties and in vitro PDT efficacies of the Pc and the nano-complex were determined and are compared herein. The singlet oxygen (1O2) yields of the Pcs were determined and are reported in DMF. A singlet oxygen quantum yield of 0.47 was obtained for the Pcs. The PDT efficacies of the complexes were thereafter determined using malignant melanoma A375 cancer cell line in vitro. An increase in the cell toxicity was observed for cells treated with Pc-BSA-Au compared to those treated with the Pc alone. The cell survival percentages were 23.1% for cells treated with Pc-BSA-Au and 48.7% for those treated with Pc alone under PDT treatments.

Double-layer hollow mesoporous silica nanoparticles for ultrasound-guided photodynamic treatment.

Cervical carcinoma persists as a major global public health burden. While conventional therapeutic modalities inevitably cause ablation of adjacent non-tumorous tissues, photodynamic therapy (PDT) offers a targeted cytotoxic strategy through a photosensitizing agent (PS). However, the hydrophobicity and lack of selective accumulation of promising PS compounds such as zinc(II) phthalocyanine (ZnPc) impedes their clinical translation as standalone agents. The present study sought to incorporate ZnPc within double-layer hollow mesoporous silica nanoparticles (DHMSN) as nanocarriers to enhance aqueous dispersibility and tumor specificity. Owing to their compartmentalized design, the hollow mesoporous silica nanoparticles (HMSN) demonstrated enhanced ultrasonic imaging contrast. Combined with the vaporization of the perfluorocarbon perfluoropentane (PFP), the HMSN-encapsulated ZnPc enabled real-time ultrasound monitoring of PDT treatment.In vivo, the innate thermal energy induced vaporization of the DHMSN-carried PFP to significantly amplify ultrasound signals from the tumor site. Results demonstrated biocompatibility, efficient PFP microbubble generation, and robust photocatalytic activity. Collectively, this investigation establishes ultrasound-guided PDT utilizing multi-layer HMSN as a targeted therapeutic strategy for cervical malignancies with mitigated toxicity.

Differences in the response of normal oral mucosa, oral leukoplakia, oral squamous cell carcinoma-derived mesenchymal stem cells, and epithelial cells to photodynamic therapy

ObjectiveThe objective of this study is to investigate the variances in transcriptome gene expression of normal oral mucosa-derived mesenchymal stem cell (OM-MSC), oral leukoplakia-derived MSC (OLK-MSC) and oral squamous cell carcinoma-derived MSC(OSCC-MSC). as Additionally, the study aims to compare the in vitro proliferation, migration, invasion ability, and response to photodynamic therapy (PDT) of these three MSC, HOK, DOK, leuk1, and Cal27 cell lines. MethodsHOK, DOK, leuk1, Cal27 cells were cultured in vitro. 3 MSC cells were obtained from OM, OLK, OSCC tissue (n = 3) and identified through flow cytometry. They were also cultured in vitro for osteogenic and lipogenic-induced differentiation. Based on the Illumina HiSeq high-throughput sequencing platform, OM-MSC, OLK-MSC, OSCC-MSC (n = 3) were subjected to transcriptome sequencing, functional annotation, and enrichment analysis of differentially expressed genes and related genes. CCK8 assay, wound healing assay, and transwell assay were performed to compare the proliferation, migration, and invasion of the seven types of cells. The 7 cells were incubated with 0, 0.125 mM, 0.25 mM, 0.5 mM, 1 mM, and 2 mM of the photosensitizer (5-aminolevulinic acid, 5-ALA) in vitro. Subsequently, they were irradiated with a 150 mM, 635 nm laser for 1 min, and the cell activity was detected using the CCK8 assay after 24 h. The mitochondrial changes in the 7 cells before and after the treatment of PDT were detected using the JC-10 probe, and the changes in ATP content were measured before and after the PDT treatment. ResultsOM-MSC, OLK-MSC, and OSCC-MSC expressed positive MSC surface markers. After osteogenic and lipogenic-induced differentiation culture, stained calcium nodules and lipid droplets were visible, meeting the identification criteria of MSC. Pathway enrichment analysis revealed that the differentially expressed genes (DEGs) of OSCC-MSC compared to OLK-MSC were primarily associated with the PI3K-Akt signaling pathway and tumor-related pathways. OSCC-MSC exhibited stronger migratory and invasive abilities compared to Cal27. The IC50 values required for OM, OLK, and OSCC-derived MSC were lower than those required for epithelial cells treated with PDT, which were 1.396 mM, 0.9063 mM, and 2.924 mM, respectively. Cell membrane and mitochondrial disruption were observed in seven types of cells after 24 h of PDT treatment. However, HOK, DOK, leuk1, and Cal27 cells had an ATP content increased. ConclusionsOLK, OSCC epithelial cells require higher concentrations of 5-ALA for PDT treatment than MSC of the same tissue origin. The concentration of 5-ALA required increases with increasing cell malignancy. Differences in the response of epithelial cells and MSC to PDT treatment may have varying impacts on OLK recurrence and malignancy.

Two Cases of Massive Subretinal Fluid Accumulation after Photodynamic Therapy for Age-related Macular Degeneration

Purpose: To report two cases of massive subretinal fluid accumulation at laser irradiated sites after photodynamic therapy in patients with age-related macular degeneration (ARMD).Case summary: (Case 1) A patient with bilateral polypoidal choroidal vasculopathy, who was treated with half-dose verteporfin photodynamic therapy (PDT), developed decreased visual acuity. On fundus examination, massive subretinal fluid accumulation was observed in the laser irradiated sites of both eyes. The subretinal fluid was reabsorbed without further treatment, and the patient's visual acuity has recovered. (Case 2) A patient with ARMD, accompanied by a choroidal neovascular membrane and accumulation of subretinal fluid in the right eye, developed decreased visual acuity on the treated eye a day after receiving half-dose PDT treatment. On fundus examination, the subretinal fluid in the right eye had increased more than 5-fold compared to pre-treatment levels. After one week, the amount of subretinal fluid decreased and the patient's visual acuity improved. However, since retinal exudate still remained, intravitreal bevacizumab treatment was administered. Thereafter, the patient’s fundus findings were unremarkable.Conclusions: In the case of photodynamic therapy for ARMD, a large amount of subretinal fluid may occur as a rare complication. The subretinal fluid was naturally absorbed, but close observation is needed with the possibility of developing subretinal fluid in the event of decreased vision after photodynamic therapy.

Clinical photodynamic therapy: The evolution of photodynamic therapy treatment of head and neck cancer

The modern era of photodynamic therapy (PDT) treatment of human cancer began in earnest in 1978, with the publication by Dougherty et al. of the first large series of humans with refractory or recurrent skin cancers successfully treated with PDT using HpD (Photofrin). The first human series of head and neck cancer patients successfully treated with PDT (Photofrin) was published in 1985, by Keller et al. Since that time, numerous clinical investigators around the world have treated thousands of head and neck cancer patients with PDT in clinical trials. These head and neck cancer PDT clinical trials enrolled patients with various stages of disease, and locations of the tumor and were treated using a variety of photosensitizers. Head and neck cancer PDT treatments were performed as the primary treatment with the intent to cure, as a late-stage treatment for palliation of the tumor, or as an adjuvant or neoadjuvant treatment in combination with surgery, radiation, chemotherapy and most recently immunotherapy. Over the past five decades, head and neck cancer PDT has evolved as newer and more targeted photosensitizers became available for clinical use, as well as advances in laser and fiberoptic technologies allowing for the activating light to be successfully and more easily delivered deep into large invasive tumors. In addition, PDT can be accurately delivered using endoscopic, robotic, CT, ultrasound and MRI guidance thereby specifically targeting the tumor and reducing treatment morbidity. Significant progress has been achieved in the ease of use and treatment efficacy of head and neck cancer PDT in various stages of the disease.

Fluorescence lifetime imaging and phasor analysis of intracellular porphyrinic photosensitizers applied with different polymeric formulations

The fluorescence lifetime of a porphyrinic photosensitizer (PS) is an important parameter to assess the aggregation state of the PS even in complex biological environments. Aggregation-induced quenching of the PS can significantly reduce the yield of singlet oxygen generation and thus its efficiency as a medical drug in photodynamic therapy (PDT) of diseased tissues. Hydrophobicity and the tendency to form aggregates pose challenges on the development of efficient PSs and often require carrier systems. A systematic study was performed to probe the impact of PS structure and encapsulation into polymeric carriers on the fluorescence lifetime in solution and in the intracellular environment. Five different porphyrinic PSs including chlorin e6 (Ce6) derivatives and tetrakis(m-hydroxyphenyl)-porphyrin and -chlorin were studied in free form and combined with polyvinylpyrrolidone (PVP) or micelles composed of triblock-copolymers or Cremophor. Following incubation of HeLa cells with these systems, fluorescence lifetime imaging combined with phasor analysis and image segmentation was applied to study the lifetime distribution in the intracellular surrounding. The data suggest that for free PSs, the structure-dependent cell uptake pathways determine their state and emission lifetimes. PS localization in the plasma membrane yielded mostly monomers with long fluorescence lifetimes whereas the endocytic pathway with subsequent lysosomal deposition adds a short-lived component for hydrophilic anionic PSs. Prolonged incubation times led to increasing contributions from short-lived components that derive from aggregates mainly localized in the cytoplasm. Encapsulation of PSs into polymeric carriers led to monomerization and mostly fluorescence emission decays with long fluorescence lifetimes in solution. However, the efficiency depended on the binding strength that was most pronounced for PVP. In the cellular environment, PVP was able to maintain monomeric long-lived species over prolonged incubation times. This was most pronounced for Ce6 derivatives with a logP value around 4.5. Micellar encapsulation led to faster release of the PSs resulting in multiple components with long and short fluorescence lifetimes. The hydrophilic hardly aggregating PS exhibited a mostly stable invariant lifetime distribution over time with both carriers. The presented data are expected to contribute to optimized PDT treatment protocols and improved PS-carrier design for preventing intracellular fluorescence quenching. In conclusion, amphiphilic and concurrent hydrophobic PSs with high membrane affinity as well as strong binding to the carrier have best prospects to maintain their photophysical properties in vivo and serve thus as efficient photodynamic diagnosis and PDT drugs.

Alkylammonium Modified Photosensitizers Achieve Lysosome-Precision Photodynamic Therapy: Implications from Molecular Dynamics Simulations

Photodynamic therapy (PDT) is one of the developing treatment modalities that has been clinically approved for cancer treatment. It uses an organic photosensitizer that harnesses the light energy and converts intracellular oxygens to reactive cytotoxic species. The resulting chemicals can then damage cells and lead to cancer cell death. However, the existing photosensitizers do not show cancel cell or organelle specificity, which lowers their treatment outcomes. In this project, we used molecular dynamic simulations to demonstrate that a straightforward alkylammonium modification on photosensitizers is able to endow conventional photosensitizers with the ability to target and accumulate in lysosomes. This acquired lysosome specificity may achieve the lysosome-precision PDT experimentally, which is expected to enhance the PDT outcomes. More importantly, such organelle-precision modifications have the potential to be extended beyond PDT treatment and make contribution to drug discovery and eventually cancer treatment.

Abstract 7593: Photodynamic therapy improves therapeutic management of glioblastoma

Abstract Glioblastoma (GBM) remains a formidable challenge in the realm of oncology, primarily due to the limitations of the standard of care therapies. Photodynamic therapy (PDT), which exploits the light-activated potential of 5-aminolevulinic acid (5-ALA), emerges as a promising avenue to combat GBM. In this study, primary patient-derived cell lines, Ox5 core, and G7, served as critical subjects, exposed to light excitation at wavelengths of 410 nm, 528 nm, and 810 nm, both with and without 5-ALA (protoporphyrin IX). The central objective was to rigorously assess the efficacy of PDT, either with or without 5-ALA, in reducing cell viability and curtailing clonogenic expansion. This evaluation was performed within the context of the existing standard of care for GBM, encompassing Temozolomide (TMZ) and Radiotherapy. Our results unveiled striking insights into the potential of PDT as an innovative therapeutic strategy. Notably, Ox5 cells exhibited a remarkable reduction in viability, exceeding 70%, following exposure to PDT with 410 nm light and 5-ALA at a concentration of 50μM. A similar, albeit slightly less profound, effect was observed in G7 cells, with a viability decrease of more than 53%. These outcomes, meticulously quantified through the MTT viability assay (n=4), were reinforced by statistical significance, as indicated by p-values falling below 0.05 and, lower 0.001. Furthermore, clonogenic assays employing G7 cells provided an additional layer of evidence, demonstrating a substantial inhibition of clonogenic potential following PDT treatment with 410 nm light and 5-ALA. Immunohistochemistry techniques, particularly focusing on the cleaved caspase-3 marker, in both Ox5 core and G7 cells, underscoring the mechanistic basis of the observed cell death. In stark contrast, the conventional standard of care, involving TMZ monotherapy, was tested, and the results across four biological replicates were less significant. The relative viability of Ox5 and G7 cells exhibited no statistical significance, with p-values exceeding 0.05, implying a limited impact of this regimen on cell viability. Moreover, clonogenic assays conducted under the standard of care protocol (TMZ+/-Radiotherapy) unveiled the persistence of colonies, even at higher radiation doses of 4 and 6 Gy.In summary, PDT, specifically when implemented with 410 nm light and 5-ALA, represents a breakthrough strategy that leads to substantial cell death in both Ox5 and G7 cells. This compelling alternative therapy shines a hopeful light on the horizon of GBM treatment, providing a potentially transformative approach that can augment the current standard of care. Citation Format: Nazar Vasyliv, Karin Williams. Photodynamic therapy improves therapeutic management of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7593.

Abstract 5743: Liposome platform enables X-ray induced photodynamic therapy treatment against human triple negative breast cancer cells

Abstract In this study, we employed X-ray induced photodynamic therapy (X-PDT) for the treatment on triple negative breast cancer (TNBC) cells. To do this, we rationally developed a liposome delivery system co-loaded with protoporphyrin IX (PPIX) and perfluorooctyl bromide (PFOB). Low-dose X-ray at 2Gy was employed to activate PPIX for reactive oxygen species (ROS) generation, and the co-loading of PFOB provided additional oxygen to augment ROS production. The highly toxic ROS triggered TNBC cell death. In vitro X-PDT effects including intracellular ROS generation, cytotoxicity, cell viability and apoptosis/necrosis assay in TNBC cells were studied. Our results indicate that the nanocarriers effectively induced X-PDT effect with very low dose radiation, which makes it possible to damage cancer cells. Our strategy may offer a paradigm-shifting treatment alternative for TNBC patients who need neoadjuvant radiotherapy but wish to avoid long term detrimental effect on functional outcome by undergoing X-PDT using only a fraction of the conventional radiotherapy. Citation Format: Biyao Yang, Rui Sang, Yi Li, Ewa Goldys, Wei Deng. Liposome platform enables X-ray induced photodynamic therapy treatment against human triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5743.

Efficient Assessment of Tumor Vascular Shutdown by Photodynamic Therapy on Orthotopic Pancreatic Cancer Using High-Speed Wide-Field Waterproof Galvanometer Scanner Photoacoustic Microscopy.

To identify the vascular alteration by photodynamic therapy (PDT), the utilization of high-resolution, high-speed, and wide-field photoacoustic microscopy (PAM) has gained enormous interest. The rapid changes in vasculature during PDT treatment and monitoring of tumor tissue activation in the orthotopic pancreatic cancer model have received limited attention in previous studies. Here, a fully two-axes waterproof galvanometer scanner-based photoacoustic microscopy (WGS-PAM) system was developed for in vivo monitoring of dynamic variations in micro blood vessels due to PDT in an orthotopic pancreatic cancer mouse model. The photosensitizer (PS), Chlorin e6 (Ce6), was utilized to activate antitumor reactions in response to the irradiation of a 660 nm light source. Microvasculatures of angiogenesis tissue were visualized on a 40 mm2 area using the WGS-PAM system at 30 min intervals for 3 h after the PDT treatment. The decline in vascular intensity was observed at 24.5% along with a 32.4% reduction of the vascular density at 3 h post-PDT by the analysis of PAM images. The anti-vascularization effect was also identified with fluorescent imaging. Moreover, Ce6-PDT increased apoptotic and necrotic markers while decreasing vascular endothelial growth factor (VEGF) expression in MIA PaCa-2 and BxPC-3 pancreatic cancer cell lines. The approach of the WGS-PAM system shows the potential to investigate PDT effects on the mechanism of angiographic dynamics with high-resolution wide-field imaging modalities.

Targeted Delivery of Catalase and Photosensitizer Ce6 by a Tumor-Specific Aptamer Is Effective against Bladder Cancer In Vivo.

Photodynamic therapy (PDT) is often applied in a clinical setting to treat bladder cancer. However, current photosensitizers report drawbacks such as low efficacy, low selectivity, and numerous side effects, which have limited the clinical values of PDT for bladder cancer. Previously, we developed the first bladder cancer-specific aptamer that can selectively bind to and be internalized by bladder tumor cells versus normal uroepithelium cells. Here, we use an aptamer-based drug delivery system to deliver photosensitizer chlorine e6 (Ce6) into bladder tumor cells. In addition to Ce6, we also incorporate catalase into the drug complex to increase local oxygen levels in the tumor tissue. Compared with free Ce6, an aptamer-guided DNA nanotrain (NT) loaded with Ce6 and catalase (NT-Catalase-Ce6) can specifically recognize bladder cancer cells, produce oxygen locally, induce ROS in tumor cells, and cause mitochondrial apoptosis. In an orthotopic mouse model of bladder cancer, the intravesical instillation of NT-Catalase-Ce6 exhibits faster drug internalization and a longer drug retention time in tumor tissue compared with that in normal urothelium. Moreover, our modified PDT significantly inhibits tumor growth with fewer side effects such as cystitis than free Ce6. This aptamer-based photosensitizer delivery system can therefore improve the selectivity and efficacy and reduce the side effects of PDT treatment in mouse models of bladder cancer, bearing a great translational value for bladder cancer intravesical therapy.

The use of photodynamic therapy in actinic keratosis in comparison to cryotherapy and chemical peels

Photodynamic Therapy (PDT) is an effective treatment of actinic keratosis. 5-Aminolevulinic Acid (ALA) and Methyl Aminolevulinate (MAL) are commonly applied. However, there is a need to establish the quality of life after PDT treatment and potential conversion to squamous cell carcinomas. The objectives of the review were to compare the efficiency of PDT, the long-term reoccurrence, and cosmesis in actinic keratosis patients. Relevant studies from the year 2000 onwards involving PDT in comparison to Cryotherapy (CT) and chemical peels were collated using a combination of terms and keywords. Conflicting results were obtained when analysing PDT in comparison to CT. A conclusion could not be deducted as to whether PDT was more, less, or equivalently effective to CT However, results obtained indicated that PDT was of greater benefit in comparison to chemical peels. Additionally, in all the studies, a conclusion was made that PDT was far superior in cosmesis in comparison to conventional therapies.