Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

Conjugated Polymer-Photosensitizers for Cancer Photodynamic Therapy and Their Multimodal Treatment Strategies

Conjugated polymers (CPs) have emerged as promising candidates for photodynamic therapy (PDT) in cancer treatment due to their high fluorescence quantum yield, excellent photostability, and remarkable reactive oxygen species (ROS) generation capability. This review systematically summarizes molecular design strategies to augment CP photosensitivity efficiency, including: (1) constructing donor-acceptor (D-A) alternating structures, (2) incorporating aggregation-induced emission (AIE) moieties, (3) employing heavy-atom effects, and (4) designing hyperbranched architectures. In addition, considering the limitations of monotherapy like tumor heterogeneity, we will further discuss the synergistic treatment strategies of CP-mediated PDT in combination with other therapeutic modalities, including photothermal therapy (PTT)-PDT, immunotherapy-PDT, chemotherapy-PDT, Chemiluminescence (CL)-PDT, diagnostic technology-PDT, and chemodynamic therapy (CDT)-PDT. These multimodal approaches leverage complementary mechanisms to achieve enhanced tumor eradication efficacy.

Photodynamic priming with red light triggers adaptive immune responses in a pancreatic cancer mouse model

The poor response of pancreatic ductal adenocarcinoma (PDAC) to treatment, including immunotherapy, is attributed to its tumor microenvironment (TME). An ongoing challenge is the desmoplastic and immunosuppressed TME that evades immune surveillance. Here, we investigate transient modulation of the TME to overcome immunosuppression using a light-activated process, termed photodynamic priming (PDP). As a first step, this study captures the temporal dynamics of variations in immune infiltrates and subsequent immune responses in the TME, spleen, and blood of the KPC mouse model of PDAC post-PDP. In response to PDP, there were transient increases in tumor infiltrating lymphocytes (TIL) in tumors. The TIL population post-PDP includes an enrichment of CD8+ T cells, accompanied by temporal increases in PD-1, CTLA-4, and TIM-3 immune checkpoints on both CD8+ T and CD4+ T cells. Significant increases in CD11C+MHC-11+ dendritic cells and proliferating lymphocytes are observed in the spleen within several hours post-tumor PDP, suggesting initiation of adaptive immune responses. These observations are followed by an expansion of CD44+CD62-CD8+ effector memory T cells in the blood over several days as evidence of a systemic immune response. Post-PDP TME alterations also included the reduced formation of blood (CD31+) and lymphatic (Lyve-1+) vessels as well as decreases in PD-L1 and collagen content. Collectively, these data suggest that PDP helps to mitigate immunosuppressive mechanisms and promote enhanced tumor permeability. The temporal dynamics of the processes elucidated here pave the way to develop strategies in future work for combined PDP-immunotherapy utilizing the immune checkpoint expression dynamics for precision therapy.

Hypericin Nanoparticles-Associated Photodynamic Therapy Modulates the Biological Behavior of Hepatocellular Carcinoma by SERPINE1

Background

In recent years, photodynamic therapy (PDT) has gradually attracted the attention of researchers due to its therapeutic potential for treating malignant tumors. Hypericin (HC) is anticipated to enhance the therapeutic effect on tumors as an efficient photosensitizer (PS) for PDT. However, the role and mechanism of PDT in hepatocellular carcinoma (HCC) remain unclear.

Methods

In this study, we investigated the efficacy of hypericin nanoparticles (HC-NPs)-associated PDT (HC-NPs-PDT) on HCC to explore its anti-HCC mechanism both in vitro and in vivo. Cellular molecular experiments, as well as HCC mouse tumor models, were utilized to validate the impact of HC-NPs-PDT on HCC. Additionally, molecular docking and related experiments were employed to investigate its potential mechanism.

Results

Our findings demonstrated that HC-NPs-PDT effectively inhibits the viability, migration, and invasion abilities of HCC cells, as well as suppresses the growth of subcutaneous HCC tumors in BALB/C-nu nude mice. SERPINE1 (also known as PAI, PAI-1, PAI1, PLANH1) may be a key target of HC, as its mRNA and protein levels were significantly up-regulated following HC-NPs-PDT. This upregulation led to a decrease in mitochondrial membrane potential and promoted apoptosis of HCC cells. Additionally, inhibition of SERPINE1 partially restored changes in mitochondrial membrane potential.

Conclusion

These results suggest that HC-NPs-PDT may regulate the biological behavior of HCC by upregulating SERPINE1 expression, offering a new perspective for treating HCC.

Saliva-derived components can enhance the performance of toluidine blue in photodynamic therapy

Introduction

Oral Squamous Cell Carcinoma (OSCC) is the most common type of head and neck cancer worldwide. Currently, the most common treatment for OSCC includes a combination of surgery, radiation, and chemotherapy. However, despite the advances made in therapeutic strategies, the prognosis for patients diagnosed with OSCC remains poor, especially at later stages, which emphasizes the need for a novel treatment approach. Photodynamic therapy (PDT) has been employed as stand-alone or adjuvant therapy for OSCC.

Methods

This study investigated the potential of using salivary proteins such as histatin-5 (Hst5) or derived peptides (RR14, DR9/RR14) to perform histatin-mediated PDT. The current literature has shown that histatins have the capacity to increase cellular membrane permeability, which indicates a potential synergistic effect when combined with a photosensitive agent. Toluidine Blue O (TBO) was used as the photosensitizer (PS) singularly combined with salivary peptides RR14, DR9/RR14, and Hst5 protein, and experiments were conducted to assess its biocompatibility and photodynamic effects on human gingival fibroblasts (FGH) and oral squamous cell carcinoma (SCC-25) cell lines.

Results

The results showed that TBO concentrations below 4 μg/mL were non-cytotoxic to FGH cells, whereas concentrations up to 8 μg/mL were non-cytotoxic to SCC-25 cells. Also, the presence of histatins did not modify the absorption spectrum or photobleaching of TBO, enabling consistent production of reactive oxygen species (ROS) over time and rendering it as a stable and suitable PS for PDT. Further experiments also showed that when TBO was combined with Hst5, the ROS production increased by 186% compared to TBO alone.

Conclusion

Results suggest that the use of histatin-enhanced PS offer a promising alternative to conventional PDT, potentially improving its outcomes.

NIR-activated multifunctional agents for the combined application in cancer imaging and therapy

Anticancer therapies that combine both diagnostic and therapeutic capabilities hold significant promise for enhancing treatment efficacy and patient outcomes. Among these, agents responsive to near-infrared (NIR) photons are of particular interest due to their negligible toxicity and multifunctionality. These compounds are not only effective in photodynamic therapy (PDT), but also serve as contrast agents in various imaging modalities, including fluorescence and photoacoustic imaging. In this review, we explore the photophysical and photochemical properties of NIR-activated porphyrin, cyanine, and phthalocyanines derivatives as well as aggregation-induced emission compounds, highlighting their application in synergistic detection, diagnosis, and therapy. Special attention is given to the design and optimization of these agents to achieve high photostability, efficient NIR absorption, and significant yields of fluorescence, heat, or reactive oxygen species (ROS) generation depending on the application. Additionally, we discuss the incorporation of these compounds into nanocarriers to enhance their solubility, stability, and target specificity. Such nanoparticle-based systems exhibit improved pharmacokinetics and pharmacodynamics, facilitating more effective tumor targeting and broadening the application range to photoacoustic imaging and photothermal therapy. Furthermore, we summarize the application of these NIR-responsive agents in multimodal imaging techniques, which combine the advantages of fluorescence and photoacoustic imaging to provide comprehensive diagnostic information. Finally, we address the current challenges and limitations of photodiagnosis and phototherapy and highlight some critical barriers to their clinical implementation. These include issues related to their phototoxicity, limited tissue penetration, and potential off-target effects. The review concludes by highlighting future research directions aimed at overcoming these obstacles, with a focus on the development of next-generation agents and platforms that offer enhanced therapeutic efficacy and imaging capabilities in the field of cancer treatment.

Engineering Radiocatalytic Nanoliposomes with Hydrophobic Gold Nanoclusters for Radiotherapy Enhancement

Chemoradiation therapy is on the forefront of pancreatic cancer care, and there is a continued effort to improve its safety and efficacy. Liposomes are widely used to improve chemotherapy safety, and may accurately deliver high-Z element- radiocatalytic nanomaterials to cancer tissues. In this study, the interaction between X-rays and long-circulating nanoliposome formulations loaded with gold nanoclusters is explored in the context of oxaliplatin chemotherapy for desmoplastic pancreatic cancer. Hydrophobic gold nanoclusters stabilized with dodecanethiol (AuDDT) are efficiently incorporated in nanoliposomal bilayers. AuDDT-nanoliposomes significantly augmented radiation-induced •OH production, which is most effective with monochromatic X-rays at energies that exceed the K-shell electron binding energy of Au (81.7 keV). Cargo release assays reveal that AuDDT-nanoliposomes can permeabilize lipid bilayers in an X-ray dose- and formulation-dependent manner. The radiocatalytic effect of AuDDT-nanoliposomes significantly augments radiotherapy and oxaliplatin-chemoradiotherapy outcomes in 3D pancreatic microtumors. The PEGylated AuDDT-nanoliposomes display high tumor accumulation in an orthotopic mouse model of pancreatic cancer, showing promise for nanoliposomes as carriers for radiocatalytic nanomaterials. Altogether, compelling proof for chemo-radiation dose-enhancement using AuDDT-nanoliposomes is presented. Further improving the nanoliposomal loading of high-Z elements will advance the safety, efficacy, and translatability of such chemoradiation dose-enhancement approaches.

Recent progress in hematoporphyrin monomethyl ether-photodynamic therapy for port-wine stains: updates and insights

Port-wine stains (PWS) are congenital vascular malformations characterized by capillary malformations that persist and often darken over time. Traditional treatment methods, including laser therapy, have shown varying degrees of effectiveness and can be associated with significant side effects. Hematoporphyrin Monomethyl Ether-Photodynamic Therapy (HMME-PDT) has emerged as a promising alternative, offering targeted treatment with potentially fewer adverse effects. This paper aims to evaluate the clinical efficacy and potential of HMME-PDT as a treatment strategy for PWS. It provides a comprehensive review of the literature and clinical investigations to assess the application and outcomes of HMME-PDT in treating PWS. Briefly introduce the nature of PWS, innovations and challenges in treatment, the mechanism of HMME-PDT, clinical effectiveness and sonographic appearance, safety and long-term effects, and challenges and suggestions for optimizing treatment. The review highlights the mechanism by which HMME-PDT works, focusing on its ability to target abnormal blood vessels selectively. Clinical evaluations included clinical and sonographic assessments to determine the efficacy of the treatment. The findings revealed significant improvements in the clinical appearance and sonographic features of vascular lesions following HMME-PDT. The paper also discusses the utility of dermoscopy in HMME-PDT applications, factors affecting treatment efficacy, the impact of thermal assistance on the effectiveness of PDT, and the management of adverse reactions through proper nursing care. The review underscores the considerable potential of HMME-PDT as an effective treatment for PWS, noting its promising outcomes in clinical and sonographic assessments. However, it also emphasizes the need for further research to standardize treatment protocols and assess long-term outcomes.

Engineering photodynamics for treatment, priming and imaging

Photodynamic therapy (PDT) is a photochemistry-based treatment approach that relies on the activation of photosensitizers by light to locally generate reactive oxygen species that induce cellular cytotoxicity, in particular for the treatment of tumours. The cytotoxic effects of PDT are depth-limited owing to light penetration limits in tissue. However, photodynamic priming (PDP), which inherently occurs during PDT, can prime the tissue microenvironment to adjuvant therapies beyond the direct PDT ablative zone. In this Review, we discuss the underlying mechanisms of PDT and PDP, and their application to the treatment of cancer, outlining how PDP can permeabilize the tumour vasculature, overcome biological barriers, modulate multidrug resistance, enhance immune responses, increase tumour permeability and enable the photochemical release of drugs. We further examine the molecular engineering of photosensitizers to improve their pharmacodynamic and pharmacokinetic properties, increase their molecular specificity and allow image guidance of PDT, and investigate engineered cellular models for the design and optimization of PDT and PDP. Finally, we discuss alternative activation sources, including ultrasound, X-rays and self-illuminating compounds, and outline key barriers to the clinical translation of PDT and PDP.

The Latest Look at PDT and Immune Checkpoints

Photodynamic therapy (PDT) can not only directly eliminate cancer cells, but can also stimulate antitumor immune responses. It also affects the expression of immune checkpoints. The purpose of this review is to collect, analyze, and summarize recent news about PDT and immune checkpoints, along with their inhibitors, and to identify future research directions that may enhance the effectiveness of this approach. A search for research articles published between January 2023 and March 2024 was conducted in PubMed/MEDLINE. Eligibility criteria were as follows: (1) papers describing PDT and immune checkpoints, (2) only original research papers, (3) only papers describing new reports in the field of PDT and immune checkpoints, and (4) both in vitro and in vivo papers. Exclusion criteria included (1) papers written in a language other than Polish or English, (2) review papers, and (3) papers published before January 2023. 24 papers describing new data on PDT and immune checkpoints have been published since January 2023. These included information on the effects of PDT on immune checkpoints, and attempts to associate PDT with ICI and with other molecules to modulate immune checkpoints, improve the immunosuppressive environment of the tumor, and resolve PDT-related problems. They also focused on the development of new nanoparticles that can improve the delivery of photosensitizers and drugs selectively to the tumor. The effect of PDT on the level of immune checkpoints and the associated activity of the immune system has not been fully elucidated further, and reports in this area are divergent, indicating the complexity of the interaction between PDT and the immune system. PDT-based strategies have been shown to have a beneficial effect on the delivery of ICI to the tumor. The utility of PDT in enhancing the induction of the antitumor response by participating in the triggering of immunogenic cell death, the exposure of tumor antigens, and the release of various alarm signals that together promote the activation of dendritic cells and other components of the immune system has also been demonstrated, with the result that PDT can enhance the antitumor immune response induced by ICI therapy. PDT also enables multifaceted regulation of the tumor's immunosuppressive environment, as a result of which ICI therapy has the potential to achieve better antitumor efficacy. The current review has presented evidence of PDT's ability to modulate the level of immune checkpoints and the effectiveness of the association of PDT with ICIs and other molecules in inducing an effective immune response against cancer cells. However, these studies are at an early stage and many more observations need to be made to confirm their efficacy. The new research directions indicated may contribute to the development of further strategies.

Shedding Light on Chemoresistance: The Perspective of Photodynamic Therapy in Cancer Management

The persistent failure of standard chemotherapy underscores the urgent need for innovative and targeted approaches in cancer treatment. Photodynamic therapy (PDT) has emerged as a promising photochemistry-based approach to address chemoresistance in cancer regimens. PDT not only induces cell death but also primes surviving cells, enhancing their susceptibility to subsequent therapies. This review explores the principles of PDT and discusses the concept of photodynamic priming (PDP), which augments the effectiveness of treatments like chemotherapy. Furthermore, the integration of nanotechnology for precise drug delivery at the right time and location and PDT optimization are examined. Ultimately, this study highlights the potential and limitations of PDT and PDP in cancer treatment paradigms, offering insights into future clinical applications.

EUS-guided interventional therapies for pancreatic diseases

Endoscopic ultrasound (EUS) is an integrated diagnostic technique merging endoscope and ultrasound to examine the digestive system. EUS has emerged as a primary diagnostic method for pancreatic diseases due to its distinctive benefits. Over the past four decades, EUS has undergone a transformation, shifting its role from primarily diagnostic to increasingly therapeutic. Additionally, in recent years, EUS has emerged as an increasingly prominent adjunctive or alternative approach to conventional surgical interventions. This review provides a comprehensive analysis of current technological approaches in the treatment of pancreatic diseases. The dynamic interplay with diverse therapeutic approaches has reinvigorated EUS and shaped its trajectory in the management of pancreatic diseases.

An oxygen-generating metal organic framework nanoplatform as a “synergy motor” for extricating dilemma over photodynamic therapy

Photodynamic therapy (PDT) combined with metal organic frameworks (MOFs) addresses current obstacles.