Prospective close monitoring of the effect of vascular-targeted photodynamic therapy and high intensity focused ultrasound of localized prostate cancer by multiparametric magnetic resonance imaging.

PURPOSE: The aim of this study is to describe the anatomical and functional changes observed in multiparametric magnetic resonance imaging (mpMRI) during follow-up after focal therapy (FT) for localized prostate cancer (PCa). MATERIALS AND METHODS: In this prospective study, we analyzed pre- and postoperatively acquired mpMRI of 10 patients after FT (7 days; 3, 6, 9, 12 months). 7/10 (70%) patients underwent vascular-targeted photodynamic therapy (VTP). 3/10 (30%) patients underwent high-intensity focused ultrasound (HIFU). MpMR image analysis was performed using a semi-automatic software for segmentation of the prostate gland (PG) and tumor zones. Signal intensities (SI) of T2-weighted (T2w), T1-weighted (T1w),diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) images as well as volumes of the prostate gland (PGV) and tumor volumes (TV) were evaluated at each time point. RESULTS: The results showed a significant increase of PGV 7 days after FT (p = 0.042) and a significant reduction of PGV between 7 days and 6, 9 and 12 months after FT (p < 0.001). The TV increased significantly 7 days after FT (p < 0.001) and decreased significantly between 7 days and 12 months after FT (p < 0.001). There was a significant increase in SI of the ADC in the ablation zone after 6, 9 and 12 months after FT (p < 0.001). 1/9 patients (11%) had recurrent tumor on rebiopsy characterized as a a small focal lesion on mpMRI with strong diffusion restriction (low SI on ADC map and high SI on b-value DWI). CONCLUSION: MpMRI is able to represent morphologic changes of the ablated zone after FT and might be helpful to detect recurrent tumor.

Fibroblast Activation Protein-Targeted Photodynamic Therapy of Cancer-Associated Fibroblasts in Murine Models for Pancreatic Ductal Adenocarcinoma.

Patients with pancreatic ductal adenocarcinoma (PDAC) have a dismal 5 year survival of 9%. One important limiting factor for treatment efficacy is the dense tumor-supporting stroma. The cancer-associated fibroblasts in this stroma deposit excessive amounts of extracellular matrix components and anti-inflammatory mediators, which hampers the efficacy of chemo- and immunotherapies. Systemic depletion of all activated fibroblasts is, however, not feasible nor desirable and therefore a local approach should be pursued. Here, we provide a proof-of-principle of using fibroblast activation protein (FAP)-targeted photodynamic therapy (tPDT) to treat PDAC. FAP-targeting antibody 28H1 and irrelevant control antibody DP47GS were conjugated to the photosensitizer IRDye700DX (700DX) and the chelator diethylenetriaminepentaacetic acid. In vitro binding and cytotoxicity were evaluated using the fibroblast cell-line NIH-3T3 stably transfected with FAP. Biodistribution of 111In-labeled antibody-700DX constructs was determined in mice carrying syngeneic tumors of the murine PDAC cell line PDAC299, and in a genetically engineered PDAC mouse model (CKP). Then, tPDT was performed by exposing the subcutaneous or the spontaneous PDAC tumors to 690 nm light. Induction of apoptosis after treatment was assessed using automated analyses of immunohistochemistry for cleaved caspase-3. 28H1-700DX effectively bound to 3T3-FAP cells and induced cytotoxicity upon exposure to 690 nm light, whereas no binding or cytotoxic effects were observed for DP47GS-700DX. Although both 28H1-700DX and DP47GS-700DX accumulated in subcutaneous PDAC299 tumors, autoradiography demonstrated that only 28H1-700DX reached the tumor core. On the contrary, control antibody DP47GS-700DX was only present at the tumor rim. In CKP mice, both antibodies accumulated in the tumor, but tumor-to-blood ratios of 28H1-700DX were higher than that of the control. Notably, in vivo FAP-tPDT caused upregulation of cleaved caspase-3 staining in both subcutaneous and in spontaneous tumors. In conclusion, we have shown that tPDT is a feasible approach for local depletion of FAP-expressing stromal cells in murine models for PDAC.

Targeting of fibroblast activation protein in rheumatoid arthritis patients: imaging and ex vivo photodynamic therapy.

OBJECTIVE: Activated synovial fibroblasts are key effector cells in RA. Selectively depleting these based upon their expression of fibroblast activation protein (FAP) is an attractive therapeutic approach. Here we introduce FAP imaging of inflamed joints using 68Ga-FAPI-04 in a RA patient, and aim to assess feasibility of anti-FAP targeted photodynamic therapy (FAP-tPDT) ex vivo using 28H1-IRDye700DX on RA synovial explants. METHODS: Remnant synovial tissue from RA patients was processed into 6 mm biopsies and, from several patients, into primary fibroblast cell cultures. Both were treated using FAP-tPDT. Cell viability was measured in fibroblast cultures and biopsies were evaluated for histological markers of cell damage. Selectivity of the effect of FAP-tPDT was assessed using flow cytometry on primary fibroblasts and co-cultured macrophages. Additionally, one RA patient intravenously received 68Ga-FAPI-04 and was scanned using PET/CT imaging. RESULTS: In the RA patient, FAPI-04 PET imaging showed high accumulation of the tracer in arthritic joints with very low background signal. In vitro, FAP-tPDT induced cell death in primary RA synovial fibroblasts in a light dose-dependent manner. An upregulation of cell damage markers was observed in the synovial biopsies after FAP-tPDT. No significant effects of FAP-tPDT were noted on macrophages after FAP-tPDT of neighbouring fibroblasts. CONCLUSION: In this study the feasibility of selective FAP-tPDT in synovium of rheumatoid arthritis patients ex vivo is demonstrated. Furthermore, this study provides the first indication that FAP-targeted PET/CT can be used to image arthritic joints, an important step towards application of FAP-tPDT as a targeted locoregional therapy for RA.

Decision Regret and Quality of Life after Focal Therapy with Vascular-Targeted Photodynamic Therapy (TOOKAD®) for Localized Prostate Cancer.

PURPOSE: The aim of the study was to assess quality of life (QoL), decision involvement, and decisional regret after treatment with vascular-targeted photodynamic therapy (VTP) (TOOKAD®) for unilateral low-risk prostate cancer. METHODS: Validated questionnaires (EORTC QLQ-C30 and QLQ-PR25) capturing QoL post-treatment, involvement in decision-making (Control Preferences Scale) and decision regret (Decisional Regret Scale), were given to patients at the 12-month visit after undergoing VTP at our institution between May 2018 and February 2021. RESULTS: Out of 44 patients, 36 patients were included in this study and 31 (86.1%) responded to the questionnaires. Mean overall health score capturing QoL at 12 months was 79.3 (standard deviation: ±18.1). 70.9% of the patients (n = 22) had no decision regret, and 67.8% of men (n = 21) had an active role in decision-making. In control biopsy at 12 months post-treatment, 19.4% of patients (n = 7) presented with local recurrence and progression to higher Gleason score (GS) was found in 13.8% of patients (n = 5). Patients (n = 3) presenting with tumor recurrence or progression to higher GS in control biopsy showed a significantly higher level of decision regret (p < 0.009). CONCLUSION: Only 9.7% of men (n = 3) felt a strong emotion of regret at 12 months after VTP. Level of decision regret was significantly higher in patients with local recurrence or tumor progression detected in control biopsy. QoL was stable after VTP.

German S3 Evidence-Based Guidelines on Focal Therapy in Localized Prostate Cancer: The First Evidence-Based Guidelines on Focal Therapy.

BACKGROUND: Focal therapy (FT) is an option to treat localized prostate cancer (PCa) and preserve healthy prostate tissue in order to reduce known side effects from primary whole-gland treatment. The available FT modalities are manifold. Until now, national and international PCa guidelines have been cautious to propose recommendations regarding FT treatment since data from prospective controlled trials are lacking for most FT modalities. Moreover, none of the international guidelines provides a separate section on FT. In this purpose, we provide a synopsis of the consensus-based German S3 guidelines for a possible international use. SUMMARY: The recently published update of the German S3 guidelines, an evidence- and consensus-based guideline, provides a section on FT with recommendations for diagnostic work-up, indications, modalities, and follow-up. This section consists of 12 statements and recommendations for FT in the treatment of localized PCa. KEY MESSAGE: The German S3 guidelines on PCa are the first to incorporate recommendations for FT based on evidence and expert consensus including indication criteria for FT, pretreatment, and follow-up diagnostic pathways as well as an extended overview of FT techniques and the current supportive evidence.

Developments in Vascular-Targeted Photodynamic Therapy for Urologic Malignancies.

With improved understanding of cancer biology and technical advancements in non-invasive management of urological malignancies, there is renewed interest in photodynamic therapy (PDT) as a means of focal cancer treatment. The application of PDT has also broadened as a result of development of better-tolerated and more effective photosensitizers. Vascular-targeted PDT (VTP) using padeliporfin, which is a water-soluble chlorophyll derivative, allows for tumor-specific cytotoxicity and has demonstrated efficacy in the management of urologic malignancies. Herein, we describe the evolution of photodynamic therapy in urologic oncology and the role of VTP in emerging treatment paradigms.

Exendin-4 analogs in insulinoma theranostics.

Insulinomas, neuroendocrine tumors arising from pancreatic beta cells, often show overexpression of the glucagon-like peptide-1 receptor. Therefore, imaging with glucagon-like peptide analog exendin-4 can be used for diagnosis and preoperative localization. This review presents an overview of the development and clinical implementation of exendin-based tracers for nuclear imaging, and the potential use of exendin-4 based tracers for optical imaging and therapeutic applications such as peptide receptor radionuclide therapy or targeted photodynamic therapy.

[Vascular targeted photodynamic therapy in low-risk prostate cancer. A literature review]. / Photothérapie dynamique dans le cancer de la prostate à faible risque. Revue de la littérature.

INTRODUCTION: Currently, about 50% of newly prostate cancers are localized and low-risk according to D'Amico risk classification. Focal therapies whose objective is to treat only the index lesion appear as a new alternative being evaluated in the management of these cancers. Besides the interest in the control of the disease, focal therapies present a very low risk of morbidity. Vascular targeted photodynamic therapy (VTP) is one of these new emerging therapies. METHOD: An exhaustive review concerning VTP in prostate cancer was carried out. A search by the following keywords "low-risk prostate cancer", "focal treatment", "vascular targeted photodynamic therapy" "TOOKAD" was carried out in Pubmed and Embase. RESULTS: In phase II studies, VTP showed a rate of 80% negative biopsies at 6 months, with good clinical tolerance. The European phase III, randomized prospective study, comparing VTP to active surveillance showed a lower proportion of progression, as well as a more significant duration before progression for VTP. The adverse events are mostly moderate and transient. The quality of life of patients is preserved, with a moderate impact on erectile and urinary functions. CONCLUSION: VTP appear to be a promising new approach in localized low-risk prostate cancer.

FTIR study of secondary structure changes in Epidermal Growth Factor by gold nanoparticle conjugation.

Conformation of protein is vital to its function, but may get affected when processing to manufacture products. It is therefore important to understand structural changes during each step of production. In this study, we investigate secondary structure changes in the targeting protein Epidermal Growth Factor (EGF) during synthesis of theranostic bifunctional nanoparticle, devised for Photodynamic therapy of breast cancer. We acquired FTIR spectra of EGF; unconjugated, post treatment with α-lipoic acid, attached to gold nanoparticle, and bound to the bifunctional nanoprobe. We observed decreasing disordered structures and turns, and increasing loops, as the synthesis process progressed. There was an overall increase in ß-sheets in final product compared to pure EGF, but this increase was not linear and fluctuated. Previous crystal structure studies on EGF-EGFR complex have shown loops and ß-sheets to be important in the binding interaction. Since our study found increase in these structures in the final product, no adverse effect on binding function of EGF was expected. This was confirmed by functional assays. Such studies may help modify synthesis procedures, and thus secondary structures of proteins, enabling increased functionality and optimum results.

Site-selective antibody-lipid conjugates for surface functionalization of red blood cells and targeted drug delivery.

Displaying antibodies on carrier surfaces facilitates precise targeting and delivery of drugs to diseased cells. Here, we report the synthesis of antibody-lipid conjugates (ALCs) through site-selective acetylation of Lys 248 in human Immunoglobulin G (IgG) and the development of antibody-functionalized red blood cells (immunoRBC) for targeted drug delivery. ImmunoRBC with the HER2-selective antibody trastuzumab displayed on the surface (called Tras-RBC) was constructed following a three-step procedure. First, a peptide-guided, proximity-induced reaction transferred an azidoacetyl group to the ε-amino group of Lys 248 in the Fc domain. Second, the azide-modified IgG was subsequently conjugated with dibenzocyclooctyne (DBCO)-functionalized lipids via strain-promoted azide-alkyne cycloaddition (SPAAC) to result in ALCs. Third, the lipid portion of ALCs was then inserted into the cell membranes, and IgGs were displayed on red blood cells (RBCs) to construct immunoRBCs. We then loaded Tras-RBC with a photosensitizer (PS), Zinc phthalocyanine (ZnPc), to selectively target HER2-overexpressing cells, release ZnPc into cancer cells following photolysis, and induce photodynamic cytotoxicity in the cancer cells. This work showcases assembling immunoRBCs following site-selective lipid conjugation on therapeutic antibodies and the targeted introduction of PS into cancer cells. This method could apply to the surface functionalization of other membrane-bound vesicles or lipid nanoparticles for antibody-directed drug delivery.

Smart glypican-3-targeting peptide-chlorin e6 conjugates for targeted photodynamic therapy of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a highly aggressive and lethal malignancy with poor prognosis, necessitating the urgent development of effective treatments. Targeted photodynamic therapy (PDT) offers a promising way to selectively eradicate tumor cells without affecting normal cells. Inspired by promising features of peptide-drug conjugates (PDCs) in targeted cancer therapy, herein a novel glypican-3 (GPC3)-targeting PDC-PDT strategy was developed for the precise PDT treatment of HCC. The GPC3-targeting photosensitizer conjugates were developed by attaching GPC3-targeting peptides to chlorin e6. Conjugate 8b demonstrated the ability to penetrate HCC cells via GPC3-mediated entry process, exhibiting remarkable tumor-targeting capacity, superior antitumor efficacy, and minimal toxicity towards normal cells. Notably, conjugate 8b achieved complete tumor elimination upon light illumination in a HepG2 xenograft model without harm to normal tissues. Overall, this innovative GPC3-targeting conjugation strategy demonstrates considerable promise for clinical applications for the treatment of HCC.

Quantitative analysis of lesion images to evaluate the efficiency of vascular-targeted photodynamic therapy for port-wine stains: Four case reports.

SIGNIFICANCE: Vascular-targeted photodynamic therapy (V-PDT) is a clinically approved therapeutic approach for treating vascular-related diseases, such as port-wine stains (PWS). For accurate treatment, varying light irradiance is required for different lesions due to the irregularity of vascular size, shape and degree of disease, which commonly alters during different stages of V-PDT. This makes quantitative analysis of the treatment efficiency urgently needed. APPROACH: Lesion images pre- and post- V-PDT treatment of patients with PWS were used to construct a quantitative method to evaluate the differences among lesions. Image analysis techniques were applied to evaluate the V-PDT efficiency for PWS by determining the Euclidean distances and two-dimensional correlation coefficients. RESULTS: According to the image analysis, V-PDT with good treatment efficiency resulted in a larger Euclidean distance and a smaller correlation coefficient compared with the case having lower V-PDT efficiency. CONCLUSIONS: A new method to quantify the Euclidean distances and correlation coefficients has been proposed, which is promising for the quantitative analysis of V-PDT efficiency for PWS.

Synthesis, Photo-Characterizations, and Pre-Clinical Studies on Advanced Cellular and Animal Models of Zinc(II) and Platinum(II) Sulfonyl-Substituted Phthalocyanines for Enhanced Vascular-Targeted Photodynamic Therapy.

Two phthalocyanine derivatives tetra-peripherally substituted with tert-butylsulfonyl groups and coordinating either zinc(II) or platinum(II) ions have been synthesized and subsequently investigated in terms of their optical and photochemical properties, as well as biological activity in cellular, tissue-engineered, and animal models. Our research has revealed that both synthesized phthalocyanines are effective generators of reactive oxygen species (ROS). PtSO2tBu demonstrated an outstanding ability to generate singlet oxygen (ΦΔ = 0.87-0.99), while ZnSO2tBu in addition to 1O2 (ΦΔ = 0.45-0.48) generated efficiently other ROS, in particular ·OH. Considering future biomedical applications, the affinity of the tested phthalocyanines for biological membranes (partition coefficient; log Pow) and their primary interaction with serum albumin were also determined. To facilitate their biological administration, a water-dispersible formulation of these phthalocyanines was developed using Pluronic triblock copolymers to prevent self-aggregation and improve their delivery to cancer cells and tissues. The results showed a significant increase in cellular uptake and phototoxicity when phthalocyanines were incorporated into the customizable polymeric micelles. Moreover, the improved distribution in the body and photodynamic efficacy of the encapsulated phthalocyanines were investigated in hiPSC-delivered organoids and BALB/c mice bearing CT26 tumors. Both photosensitizers exhibit strong antitumor activity. Notably, vascular-targeted photodynamic therapy (V-PDT) led to complete tumor eradication in 84% of ZnSO2tBu and 100% of PtSO2tBu-treated mice, and no recurrence has so far been observed for up to five months after treatment. In the case of PtSO2tBu, the effect was significantly stronger, offering a wider range of light doses suitable for achieving effective PDT.

A new nanoconstruct for epidermal growth factor receptor-targeted photo-immunotherapy of ovarian cancer.

Targeted photodynamic therapy (TPDT) involves the administration of a photosensitizer (PS) conjugated with a targeting moiety followed by light activation. The systemic toxicity associated with conventional therapy may thus be significantly reduced in TPDT due to the dual selectivity provided by the spatial localization of the illumination as well as the target-localizing ability of the conjugate. Herein, a photo-immuno-conjugate-associating-liposome (PICAL) for TPDT has been developed in which the FDA approved benzoporphyrin derivative monoacid A (BPD) and the Cetuximab antibody for epidermal growth factor receptor (EGFR) were associated into a stable Preformed Plain Liposome (PPL) by passive physical adsorption. Results have shown that the BPD molecules adsorbed into PICAL have stable optical behavior and a higher fluorescence quantum yield than free-BPD. The Cetuximab adsorbed into PPL selectively binds to cells that overexpress EGFR. The inhibition of EGFR signaling by PICAL has enhanced PDT-mediated ovarian cancer cell death. FROM THE CLINICAL EDITOR: In this basic science study, a photo-immuno-conjugate-associating-liposome for targeted photodynamic therapy is investigated. The FDA-approved benzoporphyrin derivative monoacid A and an epidermal growth factor receptor antibody were assembed into a stable Preformed Plain Liposome (PPL) by passive physical adsorption. The authors demonstrate therapeutic efficacy of the above construct in an ovarian tumor system.

Photoactive immunoconjugates for targeted photodynamic therapy of cancer.

Photodynamic therapy (PDT) has been used as an alternative or as a complement of conventional approaches for cancer treatment. In PDT, the reactive oxygen species (ROS) produced from the interaction between the photosensitizer (PS), visible light and molecular oxygen, kill malignant cells by triggering a cascade of cytotoxic reactions. In this process, the PS plays an extremely important role in the effectiveness of the therapy. In the present work, a new photoimmunoconjugate (PIC), based on cetuximab and the known third generation PS-glycophthalocyanine ZnPcGal4, was synthesized via reductive amination. The rationale behind this was the simultaneous cancer-associated specific targeting of PIC and photosensitization of targeted receptor positive cells. Varied reaction parameters and photodynamic conditions, such as PS concentrations and both type and intensities of light, were optimized. ZnPcGal4 showed significant photoactivity against EGFR expressing A431, EGFR-transfected HCT116 and HT29 cells when irradiated with white light of stronger intensity (38 mW/cm2). Similarly, the synthesized PICs-T1 and T2 also demonstrated photoactivity with high intensity white light. The best optimized PIC: sample 28 showed no precipitation and aggregation when inspected visually and analyzed through SE-HPLC. Fluorescence excitation of sample 28 and 125I-sample 28 radioconjugate (125I-PIC, 125I-radiolabeling yield ≥95%, determined with ITLC) at 660 nm showed presence of appended ZnPcGal4. In addition, simultaneous fluorescence and radioactivity detection of the 125I-PIC in serum and PBS (pH 7.4) for the longest incubated time point of 72 h, respectively, and superimposed signals thereof demonstrated ≥99% of loading and/or labeling yield, assuring overall stability of the PIC and corresponding PIC-radioconjugate w.r.t. both the appended ZnPcGal4 and bound-125I. Moreover, real-time binding analyses on EGFR-transfected HCT116 cells showed specific binding of 125I-PIC, suggesting no alternation in the binding kinetics of the mAb after appending it with ZnPcGal4. These results suggest dual potential applications of synthesized PICs both for PDT and radio-immunotherapy of cancer.

System for Self-excited Targeted Photodynamic Therapy Based on the Multimodal Protein DARP-NanoLuc-SOPP3.

Despite the significant potential of photodynamic therapy (PDT) as a minimally invasive treatment modality, the use of this method in oncology has remained limited due to two serious problems: 1) limited penetration of the excitation light in tissues, which makes it impossible to affect deep-seated tumors and 2) use of chemical photosensitizers that slowly degrade in the body and cause photodermatoses and hyperthermia in patients. To solve these problems, we propose a fully biocompatible targeted system for PDT that does not require an external light source. The proposed system is based on bioluminescent resonance energy transfer (BRET) from the oxidized form of the luciferase substrate to the photosensitizing protein SOPP3. The BRET-activated system is composed of the multimodal protein DARP-NanoLuc-SOPP3, which contains a BRET pair NanoLuc-SOPP3 and a targeting module DARPin. The latter provides the interaction of the multimodal protein with tumors overexpressing tumor-associated antigen HER2 (human epidermal growth factor receptor type II). In vitro experiments in a 2D monolayer cell culture and a 3D spheroid model have confirmed HER2-specific photo-induced cytotoxicity of the system without the use of an external light source; in addition, experiments in animals with subcutaneous HER2-positive tumors have shown selective accumulation of DARP-NanoLuc-SOPP3 on the tumor site. The fully biocompatible system for targeted BRET-induced therapy proposed in this work makes it possible to overcome the following limitations: 1) the need to use an external light source and 2) the side phototoxic effect from aberrant accumulation of chemical photosensitizers. The obtained results demonstrate that the fully protein-based self-excited BRET system has a high potential for targeted PDT.

Effect of 5-aminolevulinic Acid on Mitochondrial Activity.

BACKGROUND: Mitochondrial dysfunction is considered an important mechanism in the pathogenesis of various diseases. Therefore, mitochondria are currently being considered as subjects for targeted therapies, particularly, phototherapy using 5-aminolevulinic acid. This study aimed to investigate the activity of mitochondria in cells with different mutation loads. MATERIALS AND METHODS: The study was conducted using 11 cybrid lines obtained from the THP-1 cell line (a human monocytic leukemia cell line) and platelets of patients with different mitochondrial mutations. RESULTS: Our results illustrate that 5-aminolevulinic acid was metabolized equally in all cell lines, however, there was a significant decrease in mitochondrial potential, which differed among lines. CONCLUSIONS: The results of this study can be used to develop a personalized therapeutic approach based on different mitochondrial activities.

Biomimetic lipid nanoparticles for homologous-targeting and enhanced photodynamic therapy against glioma.

Biomimetic nano-platforms have attracted extensive attention due to their good biocompatibility, low immunogenicity, and homologous targeting to lesions. In this study, glioma cell membranes are used to encapsulate indocyanine green (ICG) loaded nanoparticles (SLNP/ICG), termed as SLNP/ICG@M for targeted photodynamic therapy (PDT) against glioma. Cell membrane modification significantly enhances cellular uptake of SLNP/ICG@M in homologous glioma cells in vitro and tumor distribution in vivo. Furthermore, SLNP/ICG@M can stimulate glioma cells to generate plentiful reactive oxygen species (ROS) under NIR irradiation, finally producing excellent photo-cytotoxicity and the optimal tumor growth inhibition with a tumor suppression rate of 93.2%. We also confirm that SLNP/ICG@M combined with NIR irradiation could activate mitochondria mediated apoptosis pathway, and the increased proliferation of CD4+ T cells and CD8+ T cells accompanied by immune activation further enhances PDT effect of SLNP/ICG@M. Herein, SLNP/ICG@M is a promising biomimetic nano drug delivery system for glioma targeted PDT therapy.

Pyrrolopyrrole aza-BODIPY-based NIR-II fluorophores for in vivo dynamic vascular dysfunction visualization of vascular-targeted photodynamic therapy.

Real-time monitoring vascular responses is crucial for evaluating the therapeutic effects of vascular-targeted photodynamic therapy (V-PDT). Herein, we developed a highly-stable and bright aggregation induced emission (AIE) fluorophore (PTPE3 NP) for dynamic fluorescence (FL) imaging of vascular dysfunction beyond 1300 nm window during V-PDT. The superior brightness (ϵmaxΦf>1000 nm ≈ 180.05 M-1 cm-1) and high resolution of PTPE3 NP affords not only high-clarity images of whole-body and local vasculature (hindlimbs, mesentery, and tumor) but also high-speed video imaging for tracking blood circulation process. By virtue of the NPs' prolonged blood circulation time (t1/2 ≈ 86.5 min) and excellent photo/chemical (pH, RONS) stability, mesenteric and tumor vascular dysfunction (thrombosis formation, vessel occlusion, and hemorrhage) can be successfully visualized during V-PDT by FL imaging for the first time. Furthermore, the reduction of blood flow velocity (BFV) can be monitored in real time for precisely evaluating efficacy of V-PDT. These provide a powerful approach for assessing vascular responses during V-PDT and promote the development of advanced fluorophores for biological imaging.

A Photoactive Supramolecular Complex Targeting PD-L1 Reveals a Weak Correlation between Photoactivation Efficiency and Receptor Expression Levels in Non-Small-Cell Lung Cancer Tumor Models.

Photo-immunotherapy uses antibodies conjugated to photosensitizers to produce nanostructured constructs endowed with targeting properties and photo-inactivation capabilities towards tumor cells. The superficial receptor density on cancer cells is considered a determining factor for the efficacy of the photodynamic treatment. In this work, we propose the use of a photoactive conjugate that consists of the clinical grade PD-L1-binding monoclonal antibody Atezolizumab, covalently linked to either the well-known photosensitizer eosin or the fluorescent probe Alexa647. Using single-molecule localization microscopy (direct stochastic optical reconstruction microscopy, dSTORM), and an anti-PD-L1 monoclonal antibody labelled with Alexa647, we quantified the density of PD-L1 receptors exposed on the cell surface in two human non-small-cell lung cancer lines (H322 and A549) expressing PD-L1 to a different level. We then investigated if this value correlates with the effectiveness of the photodynamic treatment. The photodynamic treatment of H322 and A549 with the photo-immunoconjugate demonstrated its potential for PDT treatments, but the efficacy did not correlate with the PD-L1 expression levels. Our results provide additional evidence that receptor density does not determine a priori the level of photo-induced cell death.