Combinatorial therapeutic approaches of photodynamic therapy and immune checkpoint blockade for colon cancer treatment

PAK1 inhibition increases TRIM21-induced PD-L1 degradation and enhances responses to anti-PD-1 therapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) is a common malignancy with a 5-year survival <10 %. Immunosuppressive tumor microenvironment (TME) plays a critical role in the progression of PDA. In recent years, programmed death-ligand 1 (PD-L1)/programmed cell death protein-1 (PD-1) blockade has emerged as a potent anti-tumor immunotherapy, while is yet to achieve significant clinical benefits for PDA patients. P21-Activated kinase 1 (PAK1) is highly upregulated in PDA and has been reported to be involved in the regulation of anti-tumor immunity. This study aims to investigate the combined effect of PAK1 inhibition and anti-PD-1 therapy on PDA and the underlying mechanisms. We have shown that PAK1 expression positively correlated with PD-L1 in PDA patients, and that inhibition of PAK1 downregulated PD-L1 expression of PDA cells. More importantly, we have demonstrated that PAK1 competed with PD-L1 in binding to tripartite motif-containing protein 21 (TRIM21), a ubiquitin E3 ligase, resulting in less ubiquitination and degradation of PD-L1. Moreover, PAK1 inhibition promoted CD8+ T cells activation and infiltration. In a murine PDA model, the combination of PAK1 inhibition and anti-PD-1 therapy showed significant anti-tumor effects compared with the control or monotherapy. Our results indicated that the combination of PAK1 inhibition and anti-PD-1 therapy would be a more effective treatment for PDA patients.

Mechanism and potentialities of photothermal and photodynamic therapy of transition metal dichalcogenides (TMDCs) against cancer

The ultimate goal of nanoparticle-based phototherapy is to suppress tumor growth. Photothermal therapy (PTT) and photothermal photodynamic therapy (PDT) are two types of physicochemical therapy that use light radiation with multiple wavelength ranges in the near-infrared to treat cancer. When a laser is pointed at tissue, photons are taken in the intercellular and intracellular regions, converting photon energy to heat. It has attracted much interest and research in recent years. The advent of transition materials dichalcogenides (TMDCs) is a revolutionary step in PDT/PTT-based cancer therapy. The TMDCs is a multilayer 2D nano-composite. TMDCs contain three atomic layers in which two chalcogens squash in the transition metal. The chalcogen atoms are highly reactive, and the surface characteristics of TMDCs help them to target deep cancer cells. They absorb Near Infrared (NIR), which kills deep cancer cells. In this review, we have discussed the history and mechanism of PDT/PTT and the use of TMDCs and nanoparticle-based systems, which have been practiced for theranostics purposes. We have also discussed PDT/PTT combined with immunotherapy, in which the cancer cell apoptosis is done by activating the immune cells, such as CD8+.

Advances in NIR-Responsive Natural Macromolecular Hydrogel Assembly Drugs for Cancer Treatment

Cancer is a serious disease with an abnormal proliferation of organ tissues; it is characterized by malignant infiltration and growth that affects human life. Traditional cancer therapies such as resection, radiotherapy and chemotherapy have a low cure rate and often cause irreversible damage to the body. In recent years, since the traditional treatment of cancer is still very far from perfect, researchers have begun to focus on non-invasive near-infrared (NIR)-responsive natural macromolecular hydrogel assembly drugs (NIR-NMHADs). Due to their unique biocompatibility and extremely high drug encapsulation, coupling with the spatiotemporal controllability of NIR, synergistic photothermal therapy (PTT), photothermal therapy (PDT), chemotherapy (CT) and immunotherapy (IT) has created excellent effects and good prospects for cancer treatment. In addition, some emerging bioengineering technologies can also improve the effectiveness of drug delivery systems. This review will discuss the properties of NIR light, the NIR-functional hydrogels commonly used in current research, the cancer therapy corresponding to the materials encapsulated in them and the bioengineering technology that can assist drug delivery systems. The review provides a constructive reference for the optimization of NIR-NMHAD experimental ideas and its application to human body.

Photodynamic Therapy-Induced Anti-Tumor Immunity: Influence Factors and Synergistic Enhancement Strategies

Photodynamic therapy (PDT) is an approved therapeutic procedure that exerts cytotoxic activity towards tumor cells by activating photosensitizers (PSs) with light exposure to produce reactive oxygen species (ROS). Compared to traditional treatment strategies such as surgery, chemotherapy, and radiation therapy, PDT not only kills the primary tumors, but also effectively suppresses metastatic tumors by activating the immune response. However, the anti-tumor immune effects induced by PDT are influenced by several factors, including the localization of PSs in cells, PSs concentration, fluence rate of light, oxygen concentration, and the integrity of immune function. In this review, we systematically summarize the influence factors of anti-tumor immune effects mediated by PDT. Furthermore, an update on the combination of PDT and other immunotherapy strategies are provided. Finally, the future directions and challenges of anti-tumor immunity induced by PDT are discussed.

Revolutionizing cancer treatment: nanotechnology-enabled photodynamic therapy and immunotherapy with advanced photosensitizers

Nanotechnology-enhanced photodynamic therapy (PDT) and immunotherapy are emerging as exciting cancer therapeutic methods with significant potential for improving patient outcomes. By combining these approaches, synergistic effects have been observed in preclinical studies, resulting in enhanced immune responses to cancer and the capacity to conquer the immunosuppressive tumor microenvironment (TME). Despite challenges such as addressing treatment limitations and developing personalized cancer treatment strategies, the integration of nanotechnology-enabled PDT and immunotherapy, along with advanced photosensitizers (PSs), represents an exciting new avenue in cancer treatment. Continued research, development, and collaboration among researchers, clinicians, and regulatory agencies are crucial for further advancements and the successful implementation of these promising therapies, ultimately benefiting cancer patients worldwide.

Single-Cell RNA Sequencing Reveals Immuno-Oncology Characteristics of Tumor-Infiltrating T Lymphocytes in Photodynamic Therapy-Treated Colorectal Cancer Mouse Model

Photodynamic therapy (PDT) has shown promise in reducing metastatic colorectal cancer (CRC); however, the underlying mechanisms remain unclear. Modulating tumor-infiltrating immune cells by PDT may be achieved, which requires the characterization of immune cell populations in the tumor microenvironment by single-cell RNA sequencing (scRNA-seq). Here, we determined the effect of Chlorin e6 (Ce6)-mediated PDT on tumor-infiltrating T cells using scRNA-seq analysis. We used a humanized programmed death-1/programmed death ligand 1 (PD-1/PD-L1) MC38 cell allograft mouse model, considering its potential as an immunogenic cancer model and in combination with PD-1/PD-L1 immune checkpoint blockade. PDT treatment significantly reduced tumor growth in mice containing hPD-1/PD-L1 MC38 tumors. scRNA-seq analysis revealed that the PDT group had increased levels of CD8+ activated T cells and CD8+ cytotoxic T cells, but decreased levels of exhausted CD8+ T cells. PDT treatment also enhanced the infiltration of CD8+ T cells into tumors and increased the production of key effector molecules, including granzyme B and perforin 1. These findings provide insight into immune-therapeutic modulation for CRC patients and highlight the potential of PDT in overcoming immune evasion and enhancing antitumor immunity.

Photodynamic Therapy for Inflammatory and Cancerous Diseases of the Intestines: Molecular Mechanisms and Prospects for Application

Photodynamic therapy (PDT) is a minimally invasive treatment that effectively targets cancer and inflammatory diseases. It has gained recognition for its efficacy, low toxicity, and potential for repeated use. Colorectal cancer (CRC) and inflammatory bowel diseases (IBD), including Crohn's disease (CD), and ulcerative colitis (UC), impose a significant burden on global intestinal health, with increasing incidence and prevalence rates. PDT shows promise as an emerging approach for gastrointestinal disease treatment, particularly IBD and CRC. Extensive preclinical research has demonstrated the safety and effectiveness of PDT for IBD and CRC, while clinical studies are currently underway. This review provides an overview of the underlying mechanisms responsible for the anti-inflammatory and anti-tumor effects of PDT, offering insights into the clinical application of PDT in IBD and CRC treatment. It is expected that this review will serve as a valuable reference for future research on PDT for CRC and IBD, contributing to advancements in the treatment of inflammatory and cancerous diseases of the intestines.

Novel technologies for applying immune checkpoint blockers

Cancer cells develop several ways to subdue the immune system among others via upregulation of inhibitory immune checkpoint (ICP) proteins. These ICPs paralyze immune effector cells and thereby enable unfettered tumor growth. Monoclonal antibodies (mAbs) that block ICPs can prevent immune exhaustion. Due to their outstanding effects, mAbs revolutionized the field of cancer immunotherapy. However, current ICP therapy regimens suffer from issues related to systemic administration of mAbs, including the onset of immune related adverse events, poor pharmacokinetics, limited tumor accessibility and immunogenicity. These drawbacks and new insights on spatiality prompted the exploration of novel administration routes for mAbs for instance peritumoral delivery. Moreover, novel ICP drug classes that are adept to novel delivery technologies were developed to circumvent the drawbacks of mAbs. We therefore review the state-of-the-art and novel delivery strategies of ICP drugs.

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.

Small Animal In Situ Drug Delivery Effects via Transdermal Microneedles Array versus Intravenous Injection: A Pilot Observation Based on Photoacoustic Tomography

Intravenous injection is a rapid, low-cost, and direct method that is commonly used to deliver multifarious biotherapeutics and vaccines. However, intravenous injection often causes trauma or tissue injury that requires professional operation. Transdermal drug delivery overcomes the aforementioned defects, and the microneedles (MNs) array is one of the most promising transdermal drug delivery platforms. Timely, precise, and non-invasive monitoring and evaluation of the effects of MNs in transdermal administration is significant to the research of drug efficiency response to specific diseases. In this sense, photoacoustic computed tomography (PACT), which provides wavelength-selective and deep-penetrating optical contrast, could be a promising imaging tool for in situ evaluation of the treatment effects. In this work, we propose the use of PACT to non-invasively assess the effects of real-time drug delivery in glioma tumors through transdermal administration with degradable indocyanine green-loaded hyaluronic acid MNs (ICG-HA-MNs). The outcome is systematically and quantitatively compared with that via intravenous injection. It is found that the photoacoustic signals of ICG in the tumor site express a faster elevation and shorter duration time in the intravenous injection group; by contrast, the photoacoustic signals demonstrate a lower intensity but prolonged duration time in the MNs group. The observed phenomenon indicates faster response but shorter drug duration for intravenous injection, which is in contrast with the lower loading but prolonged performance for transdermal drug delivery with MNs. These results exhibit good consistency with the earlier, common-sense findings reported from other aspects, confirming that PACT can serve as a potential imaging tool to precisely, non-invasively, and quickly evaluate in situ drug delivery effects and provide constructive guidance for the design and fabrication of microneedles.

Short Linear Motifs in Colorectal Cancer Interactome and Tumorigenesis

Colorectal tumorigenesis is driven by alterations in genes and proteins responsible for cancer initiation, progression, and invasion. This multistage process is based on a dense network of protein-protein interactions (PPIs) that become dysregulated as a result of changes in various cell signaling effectors. PPIs in signaling and regulatory networks are known to be mediated by short linear motifs (SLiMs), which are conserved contiguous regions of 3-10 amino acids within interacting protein domains. SLiMs are the minimum sequences required for modulating cellular PPI networks. Thus, several in silico approaches have been developed to predict and analyze SLiM-mediated PPIs. In this review, we focus on emerging evidence supporting a crucial role for SLiMs in driver pathways that are disrupted in colorectal cancer (CRC) tumorigenesis and related PPI network alterations. As a result, SLiMs, along with short peptides, are attracting the interest of researchers to devise small molecules amenable to be used as novel anti-CRC targeted therapies. Overall, the characterization of SLiMs mediating crucial PPIs in CRC may foster the development of more specific combined pharmacological approaches.

Engineering Fe/Mn-doped zinc oxide nanosonosensitizers for ultrasound-activated and multiple ferroptosis-augmented nanodynamic tumor suppression

As an effective tumor-therapeutic modality, ultrasound-triggered sonodynamic therapy (SDT) has been extensively explored to induce cancer cell death by activating sonosensitizers to generate reactive oxygen species (ROS). However, the traditional inorganic semiconductor-based sonosensitizers still suffer from inefficient ROS production because of the low separation efficiency of electrons and holes (e^-/h⁺) and their fast recombination. Herein, the iron (Fe) and manganese (Mn) co-doped zinc oxide nanosonosensitizers have been rationally designed and engineered for augmenting the SDT efficiency against tumor by inducing both multiple ferroptosis and apoptosis of tumor cells. The Fe/Mn component was co-doped into the nannostructure of ZnO nanosonosensitizers, which not only catalyzed the Fenton reaction in the hydrogen peroxide-overexpressed tumor microenvironment to produce ROS, but also depleted intracellular glutathione to suppress the consumption of ROS. The doping nanostructure in the engineered nanosonosensitizers substantially augmented the SDT efficacy of ZnO nanosonosensitizers by promoting the separation and hindering the recombination of e^-/h⁺ under ultrasound activation. The multiple ferroptosis and apoptosis in the enhanced SDT effect of Fe/Mn co-doped ZnO nanosonosensitizers were solidly demonstrated both in vitro and in vivo on tumor-bearing mice in accompany with the detailed mechanism assessment by RNA sequenching. This work provides a distinct strategy to augment the nanomedicine-enabled SDT efficency by engineering the inorganic semiconductor-based nanosonosensitizers with transitional metal doping and inducing multiple cell-death pathways including ferroptosis.