Photodynamic therapy

A hypoxia responsive silicon phthalocyanine containing naphthquinone axial ligands for photodynamic therapy activity

A liposome loaded‑silicon (IV) phthalocyanine (SiPc) containing naphthoquinone axial ligands as hypoxia-responsive a prodrug-like moieties (Prodrug-SiPc), is herein reported. With the help of computational methods, this study assessed the photophysical, photochemical and electrochemical redox properties of the Prodrug-SiPc to elucidate the relationship between material structure and properties. The attachment of the axial quinoid moieties endowed the Prodrug-SiPc with Type I/II photochemical and prodrug-like properties. Following liposomal encapsulation, the therapeutic efficacy of Prodrug-SiPc-liposomes was investigated against Michigan Cancer Foundation-7 (MCF-7) and Henrietta Lacks (Hela) cancer cells as in vitro cancer models and revealed that the as-synthesized Prodrug-SiPc-liposomes are potential photodynamic therapy (PDT) drug candidates. The Prodrug-SiPc-liposome takes full advantage of the hypoxic microenvironment of tumors - a side effect PDT - to trigger therapy, resulting in significantly enhanced efficacy compared to typical PDT. This work highlights the importance of multiple characteristics in designing new and effective photosensitizer candidates.

A new photodynamic therapy photosensitizer (p1) promotes apoptosis of keloid fibroblasts by targeting caspase-8

Photodynamic therapy (PDT) is a new therapy for treating cancer with less toxicity, high selectivity, good cooperativity, and repetitive usability. However, keloid treatment by PDT is mainly focused on clinical appearance, and few studies have been conducted on the mechanisms of PDT. In this study, key factors of the classical mitochondrial apoptosis signaling pathway were measured to assess the effect of a new PDT photosensitizer (p1). A specific inhibitor of caspase-8 (Z-IETD-FMK) was also used to verify the possible mechanisms. Twelve samples were obtained from 12 patients (six with keloids and six without) selected randomly from the Department of Plastic Surgery at Peking Union Medical College Hospital from January to December 2020. After cell culture, fibroblasts were divided into 13 groups. The morphology of fibroblasts in each group was observed by microscopy. Cell activity was measured by cell counting kit-8, and cell apoptotic morphology was observed by TUNEL staining. The reactive oxygen species (ROS) relative value was measured by a ROS test kit. The expression levels of key mitochondrial factors (caspase-3, caspase-8, cytochrome-c, Bax, and Bcl-2) were assessed by western blot, and mRNA expression of caspase-3 and caspase-8 was measured by RT-qPCR. We showed that p1 had a satisfactory proapoptotic effect on keloid fibroblasts by increasing the expression of ROS, caspase-3, caspase-8, and cytochrome-c, and decreasing the Bcl-2/Bax ratio; however, this effect was partially inhibited by Z-IETD-FMK, indicating that caspase-8 may be one of the p1's targets to achieve the proapoptotic effect.

Recent Progress of Gold-Based Nanostructures towards Future Emblem of Photo-Triggered Cancer Theranostics: A Special Focus on Combinatorial Phototherapies

Cancer is one of the most dangerous health problems in the millennium and it is the third foremost human cause of death in the universe. Traditional cancer treatments face several disadvantages and cannot often afford adequate outcomes. It has been exhibited that the outcome of several therapies can be improved when associated with nanostructures. In addition, a modern tendency is being developed in cancer therapy to convert single-modal into multi-modal therapies with the help of existing various nanostructures. Among them, gold is the most successful nanostructure for biomedical applications due to its flexibility in preparation, stabilization, surface modifications, less cytotoxicity, and ease of bio-detection. In the past few decades, gold-based nanomaterials rule cancer treatment applications, currently, gold nanostructures were the leading nanomaterials for synergetic cancer therapies. In this review article, the synthesis, stabilization, and optical properties of gold nanostructures have been discussed. Then, the surface modifications and targeting mechanisms of gold nanomaterials will be described. Recent signs of progress in the application of gold nanomaterials for synergetic cancer therapies such as photodynamic and photo-thermal therapies in combination with other common interventions such as radiotherapy, chemotherapy, and will be reviewed. Also, a summary of the pharmacokinetics of gold nanostructures will be delivered. Finally, the challenges and outlooks of the gold nanostructures in the clinics for applications in cancer treatments are debated.

Porphyrin Macrocycles: General Properties and Theranostic Potential

Despite specialists' efforts to find the best solutions for cancer diagnosis and therapy, this pathology remains the biggest health threat in the world. Global statistics concerning deaths associated with cancer are alarming; therefore, it is necessary to intensify interdisciplinary research in order to identify efficient strategies for cancer diagnosis and therapy, by using new molecules with optimal therapeutic potential and minimal adverse effects. This review focuses on studies of porphyrin macrocycles with regard to their structural and spectral profiles relevant to their applicability in efficient cancer diagnosis and therapy. Furthermore, we present a critical overview of the main commercial formulations, followed by short descriptions of some strategies approached in the development of third-generation photosensitizers.

Highly Efficient Singlet Oxygen Generation by BODIPY-Ruthenium(II) Complexes for Promoting Neurite Outgrowth and Suppressing Tau Protein Aggregation

Singlet oxygen (¹O₂) has been recently identified as a key molecule against toxic Aβ aggregation, which is associated with the currently incurable Alzheimer's disease (AD). However, limited research has studied its efficiency against tau protein aggregation, the other major hallmark of AD. Herein, we designed and synthesized boron-dipyrromethene (BODIPY)-ruthenium conjugates and isolated three isomers. Under visible-light irradiation, the ε isomer can be photoactivated and efficiently generate singlet oxygen. Particularly, the complex demonstrated successful results in attenuating tauopathy─an appreciable decrease to 43 ± 2% at 100 nM. The photosensitizer was further found to remarkably promote neurite outgrowth and significantly increased the length and number of neurites in nerve cells. As a result of effective photoinduced singlet oxygen generation and proactive neurite outgrowth, the hybrid design has great potential for therapeutics for Alzheimer's disease.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

Advances in Liposome-Encapsulated Phthalocyanines for Photodynamic Therapy

This updated review aims to describe the current status in the development of liposome-based systems for the targeted delivery of phthalocyanines for photodynamic therapy (PDT). Although a number of other drug delivery systems (DDS) can be found in the literature and have been studied for phthalocyanines or similar photosensitizers (PSs), liposomes are by far the closest to clinical practice. PDT itself finds application not only in the selective destruction of tumour tissues or the treatment of microbial infections, but above all in aesthetic medicine. From the point of view of administration, some PSs can advantageously be delivered through the skin, but for phthalocyanines, systemic administration is more suitable. However, systemic administration places higher demands on advanced DDS, active tissue targeting and reduction of side effects. This review focuses on the already described liposomal DDS for phthalocyanines, but also describes examples of DDS used for structurally related PSs, which can be assumed to be applicable to phthalocyanines as well.

Emerging nanosonosensitizers augment sonodynamic-mediated antimicrobial therapies

With the widespread prevalence of drug-resistant pathogens, traditional antibiotics have limited effectiveness and do not yield the desired outcomes. Recently, alternative antibacterial therapies based on ultrasound (US) have been explored to overcome the crisis of bacterial pathogens. Antimicrobial sonodynamic therapy (aSDT) offers an excellent solution that relies on US irradiation to produce reactive oxygen species (ROS) and achieve antibiotic-free mediated antimicrobial effects. In addition, aSDT possesses the advantage of superior tissue penetrability of US compared to light irradiation, demonstrating great feasibility in treating deep infections. Although existing conventional sonosensitizers can produce ROS for antimicrobial activity, some limitations, such as low penetration rate, nonspecific distribution and poor ROS production under hypoxic conditions, result in suboptimal sterilization in aSDT. Recently, emerging nanosonosensitizers have enormous advantages as high-performance agents in aSDT, which overcome the deficiencies of conventional sonosensitizers as described above. Thus, nanosonosensitizer-mediated aSDT has a bright future for the management of bacterial infections. This review classifies the current available nanosonosensitizers and provides an overview of the mechanisms, biomedical applications, recent advances and perspectives of aSDT.

Development of a new minimally invasive phototherapy for lung cancer using antibody-toxin conjugate

BACKGROUND

Photodynamic therapy (PDT) is a cancer-targeted treatment that uses a photosensitizer (PS) and laser irradiation. The effectiveness of current PDT using red light for advanced cancers is limited, because red light can only reach depths within a few millimeters. To enhance the antitumor effect for lung cancers, we developed a new phototherapy, intelligent targeted antibody phototherapy (iTAP). This treatment uses a combination of immunotoxin and a PS, mono-L-aspartyl chlorin e6 (NPe6).

METHODS

We examined whether cetuximab encapsulated in endosomes was released into the cytosol by PS in PDT under light irradiation. A431 cells were treated with fluorescein isothiocyanate-labeled cetuximab, NPe6, and light irradiation and were observed with fluorescence microscopy. We analyzed the cytotoxicity of saporin-conjugated cetuximab (IT-cetuximab) in A431, A549, and MCF7 cells and the antitumor effect in model A549-bearing mice in vivo using the iTAP method.

RESULTS

Fluorescent microscopy analysis showed that the photodynamic effect of NPe6 (20 μM) and light irradiation (37.6 J/cm² ) caused the release of cetuximab from the endosome into the cytosol. In vitro analysis demonstrated that the iTAP method enhanced the cytotoxicity of IT-cetuximab by the photodynamic effect. In in vivo experiments, compared with IT-cetuximab alone or PDT alone, the iTAP method using a low dose of IT-cetuximab showed the greatest enhancement of the antitumor effect.

CONCLUSIONS

Our study is the first report of the iTAP method using NPe6 for lung cancer cells. The iTAP method may become a new, minimally invasive treatment superior to current PDT methods.

Boosting Type-I and Type-II ROS Production of Water-Soluble Porphyrin for Efficient Hypoxic Tumor Therapy

As the most successful clinically approved photosensitizers, porphyrins have been extensively employed in the photodynamic therapy (PDT) of cancers. However, their poor water solubility, aggregation-induced self-quenching on ROS generation, and a low tolerance for a hypoxic condition usually result in unsatisfied therapeutic outcomes. Therefore, great efforts have been dedicated to improving the PDT efficacy of porphyrin-type photosensitizers in treating hypoxic tumors, including combination with additional active components or therapies, which can significantly complicate the therapeutic process. Herein, we report a novel water-soluble porphyrin with O-linked cationic side chains, which exhibits good water solubility, high photostability, and significantly enhanced ROS generation efficacy in both type-I and type-II photodynamic pathways. We have also found that the end charges of side chains can dramatically affect the ROS generation of the porphyrin. The cationic porphyrin exhibited high in vitro PDT efficacy with low IC₅₀ values both in normoxia and hypoxia. Hence, during in vivo PDT study, the cationic porphyrin displayed highly effective tumor ablation capability. This study demonstrates the power of side-chain chemistry in tuning the photodynamic property of porphyrin, which offers a new effective strategy to enhance the anticancer performance of photosensitizers for fulfilling the increasing demands for cancer therapy in clinics.

Multifunctional 3D-printed bioceramic scaffolds: Recent strategies for osteosarcoma treatment

Osteosarcoma is the most prevalent bone malignant tumor in children and teenagers. The bone defect, recurrence, and metastasis after surgery severely affect the life quality of patients. Clinically, bone grafts are implanted. Primary bioceramic scaffolds show a monomodal osteogenesis function. With the advances in three-dimensional printing technology and materials science, while maintaining the osteogenesis ability, scaffolds become more patient-specific and obtain additional anti-tumor ability with functional agents being loaded. Anti-tumor therapies include photothermal, magnetothermal, old and novel chemo-, gas, and photodynamic therapy. These strategies kill tumors through novel mechanisms to treat refractory osteosarcoma due to drug resistance, and some have shown the potential to reverse drug resistance and inhibit metastasis. Therefore, multifunctional three-dimensional printed bioceramic scaffolds hold excellent promise for osteosarcoma treatments. To better understand, we review the background of osteosarcoma, primary 3D-printed bioceramic scaffolds, and different therapies and have a prospect for the future.

Current advances in the application of nanomedicine in bladder cancer

Bladder cancer is the most common malignant tumor of the urinary system, however there are several shortcomings in current diagnostic and therapeutic measures. In terms of diagnosis, the diagnostic tools currently available are not sufficiently sensitive and specific, and imaging is poor, leading to misdiagnosis and missed diagnoses, which can delay treatment. In terms of treatment, current treatment options include surgery, chemotherapy, immunotherapy, gene therapy, and other emerging treatments, as well as combination therapies. However, the main reasons for poor efficacy and side effects during treatment are the lack of specificity and targeting, improper dose control of drugs and photosensitizers, damage to normal cells while attacking cancer cells, and difficulty in delivering siRNA to cancer cells. Nanomedicine is an emerging approach. Among the many nanotechnologies applied in the medical field, nanocarrier-assisted drug delivery systems have attracted extensive research interest due to their great translational value. Well-designed nanoparticles can deliver agents or drugs to specific cell types within target organs through active targeting or passive targeting (enhanced permeability and retention), which allows for imaging, diagnosis, as well as treatment of cancer. This paper reviews advances in the application of various nanocarriers and their advantages and drawbacks, with a focus on their use in the diagnosis and treatment of bladder cancer.

Image-Guided Precision Treatments

Chemotherapy, radiotherapy, and surgery are traditional cancer treatments, which usually produce unpredictable side effects and potential risks to normal healthy organs/tissues. Thus, safe and reliable treatment strategies are urgently required for maximized therapeutic efficiency to lesions and minimized risks to healthy regions. To this end, molecular imaging is responsible to undertake a specific targeting therapy. Besides that, the image guidance as a precision visualized approach for real-time in situ evaluations as well as an intraoperational navigation approach has earned attractive attention in the past decade. Along with the rapid development of multifunctional micro-/nanobiomaterials, versatile cutting-edge and advanced therapy strategies (e.g., thermal therapy, dynamic therapy, gas therapy, etc.) have been achieved and greatly contributed to the image-guided precision treatments in every aspect. Therefore, this chapter aims to discuss about both traditional and advanced cancer treatments and especially to elucidate the important roles that visualized medicine has been playing in the image-guided precision treatments.

Ex vivo purging of cancer cells from ovarian tissue using photodynamic therapy: a novel strategy to restore fertility in leukemia patients

STUDY QUESTION

Is it possible to purge leukemia cells from ovarian tissue (OT) fragments before transplantation?

SUMMARY ANSWER

Our photodynamic therapy (PDT) approach has been shown to efficiently destroy leukemia cells from tumor-infiltration mimicking models (TIMs), indicating the feasibility of this technique to purge OT samples.

WHAT IS KNOWN ALREADY

Autotransplantation of cryopreserved OT is the most suitable option to preserve fertility for prepubertal girls and women who require immediate cancer treatment. Up until now, more than 200 live births have already been reported after OT cryopreservation and transplantation. Leukemia is the 12th most common cancer in Europe among prepubertal girls and women of reproductive age and in 2020, the estimated number of new leukemia cases was higher than 33 000 in girls between 0 and 19 years old. Unfortunately, once their health has been restored, autotransplantation of cryopreserved OT for leukemia patients is not advised due to the high risk of transferring malignant cells back to the patient leading to leukemia recurrence.

STUDY DESIGN SIZE DURATION

To safely transplant the OT from leukemia patients and restore their fertility, our goal was to develop a PDT strategy to eliminate leukemia ex vivo. To this end, we designed OR141-loaded niosomes (ORN) to create the most effective formulation for ex vivo purging of acute myelogenous leukemia cells from OT fragments (n = 4). Moreover, to ensure that such treatments are not harmful to follicle survival and development so they can be deemed a potential fertility restoration alternative, the effect of the ORN-based PDT purging procedure on follicles was assessed after xenografting the photodynamic-treated OT in SCID mice (n = 5). The work was carried out between September 2020 and April 2022 at the Catholic University of Louvain.

PARTICIPANTS/MATERIALS SETTING METHODS

After establishing the best ORN formulation, our PDT approach was used to eradicate HL60 cells from ex vivo TIMs prepared by microinjection of a cancer cell suspension into OT fragments. The purging efficiency was analyzed by droplet digital polymerase chain reaction and immunohistochemical analyses. Additionally, we evaluated the effect of ORN-based PDT on follicle density, survival and development, and tissue quality in terms of fibrotic areas and vascularization after 7-day xenotransplantation to immunodeficient mice.

MAIN RESULTS AND THE ROLE OF CHANCE

The ex vivo purging of TIMs demonstrated that our PDT strategy could selectively eradicate the malignant cells from tissue fragments without affecting OT normal cells, as evidenced by PCR and immunohistochemical analysis. Regarding the effect of our PDT approach on follicle population and OT quality, our results after xenotransplantation revealed no significant difference between the follicle density of control (non-treated, grafted OT) and PDT-treated groups (2.38 ± 0.63 and 3.21 ± 1.94 morphologically normal follicles/mm², respectively). In addition, our findings showed that the control and PDT-treated OT could be equally vascularized (7.65 ± 1.45% and 9.89 ± 2.21%, respectively). Similarly, the proportions of fibrotic area did not differ between the control (15.96 ± 5.94%) and PDT-treated groups (13.32 ± 3.05%).

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

This study did not use OT fragments from leukemia patients, but TIMs created after injection of HL60 cells into OT from healthy patients. Therefore, while the results are promising, whether our PDT approach will be equally successful in eliminating malignant cells from leukemia patients remains to be assessed.

WIDER IMPLICATIONS OF THE FINDINGS

Our results showed that the purging procedure causes no significant impairment effect on follicle development and tissue quality, suggesting that our novel PDT procedure could be a promising strategy to destroy leukemia cells in fragments of OT, allowing safe transplantation in cancer survivors.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR Convention grant number T.0004.20 awarded to C.A.A.); Fondation Louvain (awarded to C.A.A.; a Ph.D. scholarship awarded to S.M., as part of a legacy from Mr Frans Heyes, and a Ph.D. scholarship awarded to A.D. as part of a legacy from Mrs. Ilse Schirmer); and Foundation Against Cancer (grant number 2018-042 awarded to A.C.). The authors declare no competing interests.

Hyper-Aggressiveness of Bystander Cells in an Anti-Tumor Photodynamic Therapy Model: Role of Nitric Oxide Produced by Targeted Cells

When selected tumor cells in a large in vitro population are exposed to ionizing radiation, they can send pro-survival signals to non-exposed counterparts (bystander cells). If there is no physical contact between irradiated and bystander cells, the latter respond to mediators from targeted cells that diffuse through the medium. One such mediator is known to be nitric oxide (NO). It was recently discovered that non-ionizing anti-tumor photodynamic therapy (PDT) can also elicit pro-survival/expansion bystander effects in a variety of human cancer cells. A novel silicone ring-based approach was used for distinguishing photodynamically-targeted cells from non-targeted bystanders. A key finding was that NO from upregulated iNOS in surviving targeted cells diffused to the bystanders and caused iNOS/NO upregulation there, which in turn stimulated cell proliferation and migration. The intensity of these responses depended on the extent of iNOS/NO induction in targeted cells of different cancer lines. Moreover, the responses could be replicated using NO from the chemical donor DETA/NO. This review will focus on these and related findings, their negative implications for clinical PDT, and how these might be averted by using pharmacologic inhibitors of iNOS activity or transcription.

Two-photon photodynamic therapy based on FRET using tumor-cell targeted riboflavin conjugated graphene quantum dot

The photodynamic therapy (PDT) is considered as a noninvasive and photo-controlled treatment for various cancers. However, its potential is not fully developed as current clinically approved photosensitizers (PSs) mainly absorb the light in the UV-visible region (less than 700 nm), where the depth of penetration is inadequate for reaching tumor cells under deeper tissue layers. Furthermore, the lack of specific accumulation capability of the conventional PSs in the tumor cells may cause serious toxicity and low treatment efficiency. To address these problems, riboflavin (Rf) conjugated and amine-functionalized nitrogen-doped graphene quantum dots (am-N-GQD) are herein proposed. Rf functions as both photosensitizer and targeting ligand by indirect excitation through intra-particle fluorescence resonance energy transfer (FRET) via two-photon (TP) excited am-N-GQD, to enhance the treatment depth, and further am-N-GQD-Rf accumulation in cancer cells using Rf transporter family (RFVTs) and Rf carrier proteins (RCPs). The one-photon (OP) and two-photon(TP)-PDT effect and cellular internalization ability of the am-N-GQD-Rf were investigated in vitro in different cancel cell lines. Besides the excellent cellular uptake as well TP-PDT capability, the superior biocompatibility of am-N-GQD-Rf in vitro makes it promising candidate in PDT.

Photosensitization of human skin fibroblasts by vemurafenib promotes pleiotropic effects on membrane-enclosed organelles and apoptosis

Vemurafenib (VB), a BRAF inhibitor and a first-line treatment for unresectable or metastatic melanoma, is strongly phototoxic towards normal skin cells. Herein, we show that in cultured HS 68 human diploid dermal fibroblasts, low concentrations of VB suffice to promote photosensitization to low doses of UVA (∼ 5 J/cm²), as evidenced by a significant decrease in cell viability. In contrast to data obtained in chemico our results support a role for ROS (reactive oxygen species). Indeed, peroxidation of cellular lipids was observed which could be alleviated by the lipophilic antioxidant BHT (2,6-di-tert-butyl-4-methylphenol). Using in vivo confocal laser scanning microscopy and vital fluorescent probes it was shown at the single cell level that the plasma membrane and lipid-rich organelles, namely mitochondria, endoplasmic reticulum, and lysosomes, as well as actin filaments, were severely damaged by the UVA-induced VB-photosensitization. Finally, we showed that mitochondrial impairment was concurrent with caspase 3/7 activation and cell death by apoptosis.

Multifunctional Photoactive Nanomaterials for Photodynamic Therapy against Tumor: Recent Advancements and Perspectives

Numerous treatments are available for cancer, including chemotherapy, immunotherapy, radiation therapy, hormone therapy, biomarker testing, surgery, photodynamic therapy, etc. Photodynamic therapy (PDT) is an effective, non-invasive, novel, and clinically approved strategy to treat cancer. In PDT, three main agents are utilized, i.e., photosensitizer (PS) drug, oxygen, and light. At first, the photosensitizer is injected into blood circulation or applied topically, where it quickly becomes absorbed or accumulated at the tumor site passively or actively. Afterward, the tumor is irradiated with light which leads to the activation of the photosensitizing molecule. PS produces the reactive oxygen species (ROS), resulting in the death of the tumor cell. However, the effectiveness of PDT for tumor destruction is mainly dependent on the cellular uptake and water solubility of photosensitizer molecules. Therefore, the delivery of photosensitizer molecules to the tumor cell is essential in PDT against cancer. The non-specific distribution of photosensitizer results in unwanted side effects and unsuccessful therapeutic outcomes. Therefore, to improve PDT clinical outcomes, the current research is mostly focused on developing actively targeted photosensitizer molecules, which provide a high cellular uptake and high absorption capacity to the tumor site by overcoming the problem associated with conventional PDT. Therefore, this review aims to provide current knowledge on various types of actively and passively targeted organic and inorganic nanocarriers for different cancers.

Macrophage cell membrane-based nanoparticles: a new promising biomimetic platform for targeted delivery and treatment

Synthetic nanoparticles with surface bioconjugation are promising platforms for targeted therapy, but their simple biological functionalization is still a challenging task against the complex intercellular environment. Once synthetic nanoparticles enter the body, they are phagocytosed by immune cells by the immune system. Recently, the cell membrane camouflage strategy has emerged as a novel therapeutic tactic to overcome these issues by utilizing the fundamental properties of natural cells. Macrophage, a type of immune system cells, plays critical roles in various diseases, including cancer, atherosclerosis, rheumatoid arthritis, infection and inflammation, due to the recognition and engulfment function of removing substances and pathogens. Macrophage membranes inherit the surface protein profiles and biointerfacing properties of source cells. Therefore, the macrophage membrane cloaking can protect synthetic nanoparticles from phagocytosis by the immune cells. Meanwhile, the macrophage membrane can make use of the natural correspondence to accurately recognize antigens and target inflamed tissue or tumor sites. In this review, we have summarized the advances in the fabrication, characterization and homing capacity of macrophage membrane cloaking nanoparticles in various diseases, including cancers, immune diseases, cardiovascular diseases, central nervous system diseases, and microbial infections. Although macrophage membrane-camouflaged nanoparticles are currently in the fetal stage of development, there is huge potential and challenge to explore the conversion mode in the clinic.

Redaporfin Development for Photodynamic Therapy and its Combination with Glycolysis Inhibitors

Photodynamic therapy (PDT) remains an underutilized treatment modality in oncology. Many efforts have been dedicated to the development of better photosensitizers, better formulations and delivery methods, rigorous planning of light dose distribution in tissues, mechanistic insight, improvement of treatment protocols and combinations with other therapeutic agents. Hopefully, progress in all these fields will eventually expand the use of PDT. Here we offer a brief review of our own contribution to the development of a photosensitizer for PDT - redaporfin - currently in Phase II clinical trials, and present data on its combination with two glycolysis inhibitors: 2-deoxyglucose and 3-bromopyruvate. We show that 3-bromopyruvate is more cytotoxic to a carcinoma cell line (CT26) than to a normal fibroblast (3T3) cell line, and that this selectivity is maintained in the in vitro combination with redaporfin-PDT. This combination was investigated in BALB/c mice with large subcutaneous CT26 tumors and it is shown that the cure rate in the combination is higher (33% cures) than in PDT (11% cures) or in 3-bromopyruvate (no cures) alone. The combination of redaporfin-PDT with 3-bromopyruvate illustrates the potential of combination therapies and how PDT benefits can be enhanced by systemic drugs with complementary targets.

Short-Wavelength Aggregation-Induced Emission Photosensitizers for Solid Tumor Therapy: Enhanced with White-Light Fiber Optic

Background

White-light photodynamic therapy (wPDT) has been used in the treatment of cancer due to its convenience, effectiveness and less painful. However, the limited penetration of white-light into the tissues leads to a reduced effectiveness of solid tumor treatment.

Methods

Two short-wavelength aggregation-induced emission (AIE) nanoparticles were prepared, PyTPA@PEG and TB@PEG, which have excitation wavelengths of 440 nm and 524 nm, respectively. They were characterized by UV, fluorescence, particle size and TEM. The ability of nanoparticles to produce reactive oxygen species (ROS) and kill cancer cells under different conditions was investigated in vitro, including white-light, after white-light penetrating the skin, laser. A white-light fiber for intra-tumor irradiation was customized. Finally, induced tumor elimination with fiber-mediated wPDT was confirmed in vivo.

Results

In vitro, both PyTPA@PEG and TB@PEG are more efficient in the production ROS when exposed to white-light compared to laser. However, wPDT also has a fatal flaw in that its level of ROS production after penetrating the skin is reduced to 20-40% of the original level. To this end, we have customized a white-light fiber for intra-tumor irradiation. In vivo, the fiber-mediated wPDT significantly induces tumor elimination with maximized therapeutic outcomes by irradiating the interior of the tumor. In addition, wPDT also has the advantage that its light source can be adapted to a wide range of photosensitizers (wavelength range 400-700 nm), whereas a laser of single wavelength can only target a specific photosensitizer.

Conclusion

This method of using optical fiber to increase the tissue penetration of white light can greatly improve the therapeutic effect of AIE photosensitizers, which is needed for the treatment of large/deep tumors and holds great promise in cancer treatment.

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (¹O₂) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.

Quaternary Ru(II) complexes of terpyridines, saccharin and 1,2-azoles: effect of substituents on molecular structure, speciation, photoactivity, and photocytotoxicity

Six photoactive ruthenium quaternary complexes (a four-component system consisting of three different N-donor ligands and Ru(II)): trans-[Ru(R-tpy)(pyz/ind)(sac)₂] (1-6) containing substituted terpyridine (R-tpy), saccharin (sac), and monodentate N-donor heterocycles were designed. Here, R-tpy = 4'-(2-furyl (1, 2); thienyl (3, 4); pyridyl (5, 6))-2,2':6',2'' terpyridines, pyz = 1H-pyrazole for 1, 3 and 5 and ind = 1H-indazole for 2, 4 and 6. The azoles are present in a large number of FDA-approved clinical drugs and bioactive molecules. The saccharin acting as a carbonic anhydrase inhibitor (CA-IX) could potentially target aggressive hypoxic tumors that overexpress CA-IX. Such multi-functional ligands bound to a Ru(II)-photocage provide ample scope to tune the electronic structures, photochemistry, and synergistic effect of the photolabile ligands in photoactivated chemotherapy (PACT). The complexes were characterized using various spectroscopic studies, and the molecular structures were determined from X-ray crystallography. They exhibit a distorted octahedral {RuN₆} geometry with equatorial sites coordinated to the tridentate N₃-donor R-tpy and N-donor pyz/ind, while two transoidal axial sites bound to the N-donor saccharinate (sac) ligands. The solvolysis kinetics showed these complexes undergo facile ligand-exchange reactions in equilibrium with varying rates reflecting the possible electronic effect of the R-groups in R-tpy. The photoreactivity of the complexes in green (λ_ex = 530 nm) LED light indicates that the complexes undergo photodissociation of the monodentate N-donors (i.e., sac/pyz/ind) and showed an efficient generation of singlet oxygen (Φ_1O2 = 0.29-0.47), signifying the potential of these complexes in PACT and/or PDT. All the complexes show good binding affinity with CT-DNA with possible intercalation from extended planar polypyridyl ligands with duplex DNA and BSA. The synchronous fluorescence study with BSA suggested preferential interaction at the tryptophan residue in the protein microenvironment. The confocal microscopy studies showed adequate permeability and localization in the cytosol and nucleus of cervical cancer (HeLa) and breast cancer (MCF7) cells. The dose-dependent cytotoxicity of the complexes for both HeLa and MCF7 cells increases upon low-energy (365 nm) photoirradiation. The mechanistic studies revealed that the complexes induce apoptosis and generate reactive oxygen species (ROS) upon green light (λ_ex = 530 nm) irradiation. Overall, these quaternary Ru(II) complexes equipped with three different types of ligands with distinct roles could pave the way for designing multi-targeted chemotherapeutic metallodrugs with synergistic roles for each bioactive ligand.

Influence of silver ion release on the inactivation of antibiotic resistant bacteria using light-activated silver nanoparticles

The widespread increase in antibiotic resistance (AR), in an extensive range of microorganisms, demands the development of alternative antimicrobials with novel non-specific low-mutation bacterial targets. Silver nanoparticles (AgNPs) and photosensitizers (PSs) are promising antimicrobial agents with broad-spectrum activity and low tendency for antimicrobial resistance development. Herein, we investigated the light-mediated oxidation of AgNPs for accelerated release of Ag⁺ in the antibacterial synergy of PS-AgNP conjugates using protoporphyrin IX (PpIX) as a PS. Also, the influence of polyethyleneimine (PEI) coated AgNPs in promoting antibacterial activity was examined. We synthesized, characterized and tested the antimicrobial effect of three nanoparticles: AgNPs, PpIX-AgNPs, and PEI-PpIX-AgNPs against a methicillin-resistant Staphylococcus aureus strain (MRSA) and a wild-type multidrug resistant (MDR) E. coli. PpIX-AgNPs were the most effective material achieving >7 log inactivation of MRSA and MDR E. coli. The order of bacterial log inactivation was PpIX-AgNPs > PEI-PpIX-AgNPs > AgNPs. This order correlates with the trend of Ag⁺ concentration released by the NPs (PpIX-AgNPs > PEI-PpIX-AgNPs > AgNPs). Our study confirms a synergistic effect between PpIX and AgNPs in the inactivation of AR pathogens with about 10-fold increase in inactivation of ARB relative to AgNPs only. The concentration of Ag⁺ released from NPs determined the log inactivation of MRSA and MDR E. coli more than either the phototoxic effect or the electrostatic interaction promoted by surface charge of nanoparticles with bacteria cells. All NPs showed negligible cytotoxicity to mammalian cells at the bacterial inhibitory concentration after 24 h exposure. These observations confirm the crucial role of optimized Ag⁺ release for enhanced performance of AgNP-based antimicrobials against AR pathogens.

D. Medeiros H, Bates M, Roshanzadeh A, Thing Teoh S, P. Ogrodzinski M, Borhan B, Lunt RR, Lunt SY. Counterion Tuning of Near-Infrared Organic Salts Dictates Phototoxicity to Inhibit Tumor Growth

Photodynamic therapy (PDT) has the potential to improve cancer treatment by providing dual selectivity through the use of both photoactive agent and light, with the goal of minimal harmful effects from either the agent or light alone. However, current PDT is limited by insufficient photosensitizers (PSs) that can suffer from low tissue penetration, insufficient phototoxicity (toxicity with light irradiation), or undesirable cytotoxicity (toxicity without light irradiation). Recently, we reported a platform for decoupling optical and electronic properties with counterions that modulate frontier molecular orbital levels of a photoactive ion. Here, we demonstrate the utility of this platform in vivo by pairing near-infrared (NIR) photoactive heptamethine cyanine cation (Cy⁺), which has enhanced optical properties for deep tissue penetration, with counterions that make it cytotoxic, phototoxic, or nontoxic in a mouse model of breast cancer. We find that pairing Cy⁺ with weakly coordinating anion FPhB^- results in a selectively phototoxic PS (CyFPhB) that stops tumor growth in vivo with minimal side effects. This work provides proof of concept that our counterion pairing platform can be used to generate improved cancer PSs that are selectively phototoxic to tumors and nontoxic to normal healthy tissues.

Reaction mechanism of nanomedicine based on porphyrin skeleton and its application prospects

Research on porphyrin-based photosensitizing drugs is becoming increasingly popular. They possess unique diagnostic capabilities and therapeutic effects that have gained wide recognition in oncology drug development. In recent years, the rapid growth of nanotechnology has brought great hope for nanopharmaceutical formulations. By combining porphyrins with various nanomaterials, people have improved the properties of porphyrin compounds, making drug delivery easier. Porphyrin-based nanoparticles can enhance the effect of photodynamic therapy for cancer treatment, providing opportunities for achieving complex targeting strategies and versatility with promising applications in drug carriers, tumor imaging, and treatment. This paper reviews recent porphyrin nanodrugs, including inorganic-organic hybrid nanoparticles, nanomicelles, self-assembled nanoparticles, and combination therapeutic nanodrugs, and their actions and effects on cancer cells when performing photodynamic therapy. It also discusses the drawbacks as well as the prospects for development.

Progress and perspectives of platinum nanozyme in cancer therapy

Malignant tumors, one of the worst-case scenarios within human health problems, are now posing an increasing threat to the well-being of the global population. At present, the treatment of malignant tumors mainly includes surgery, radiotherapy, chemotherapy, immunotherapy, etc. Radiotherapy and chemotherapy are often applied to inoperable tumors, and some other tumors after surgery as important adjuvant therapies. Nonetheless, both radiotherapy and chemotherapy have a series of side effects, such as radiation-induced lung injury, and chemotherapy-induced bone marrow suppression. In addition, the positioning accuracy of radiotherapy and chemotherapy is not assured and satisfactory, and the possibility of tumor cells not being sensitive to radiation and chemotherapy drugs is also problematic. Nanozymes are nanomaterials that display natural enzyme activities, and their applications to tumor therapy have made great progress recently. The most studied one, platinum nanozyme, has been shown to possess a significant correlation with radiotherapy sensitization of tumors as well as photodynamic therapy. However, there are still several issues that limited the usage of platinum-based nanozymes in vivo. In this review, we briefly summarize the representative studies regarding platinum nanozymes, and especially emphasize on the current challenges and the directions of future development for platinum nanozymes therapy.

Engineered upconversion nanocarriers for synergistic breast cancer imaging and therapy: Current state of art

Breast cancer is the most common type of cancer in women and is the second leading cause of cancer-related deaths worldwide. Early diagnosis and effective therapeutic interventions are critical determinants that can improve survival and quality of life in breast cancer patients. Nanotheranostics are emerging interventions that offer the dual benefit of in vivo diagnosis and therapeutics through a single nano-sized carrier. Rare earth metal-doped upconversion nanoparticles (UCNPs) with their ability to convert near-infrared light to visible light or UV light in vivo settings have gained special attraction due to their unique luminescence and tumor-targeting properties. In this review, we have discussed applications of UCNPs in drug and gene delivery, photothermal therapy (PTT), photodynamic therapy (PDT) and tumor targeting in breast cancer. Further, present challenges and future opportunities for UCNPs in breast cancer treatment have also been mentioned.

Photodynamic therapy using OR141-loaded nanovesicles for eradication of leukemic cells from ovarian tissue

In 2020, the estimated number of new leukemia cases was higher than 30,000 in girls between 0 and 19 years old. Due to cancer treatment, some of these patients may lose both endocrine and reproductive functions. Transplantation of cryopreserved ovarian tissue is not advised after cancer remission because it has a high risk of reintroducing malignant cells in the patient, potentially leading to leukemia recurrence. To safely transplant the ovarian tissue from these patients and restore their fertility, our goal was to develop a photodynamic therapy (PDT) strategy to eliminate leukemia ex vivo. To this end, we designed, optimized, and characterized OR141-loaded niosomes (ORN) to develop the most effective formulation for ex vivo purging ovarian fragments from chronic myelogenous leukemia cells. After establishing the best ORN formulation, the PDT efficiency of optimized ORN was determined for human ovarian stromal cells and acute myeloid leukemia cell line (HL60). Blank niosomes treatment on ovarian stromal cells causes no significant toxicity, showing that the composition of the nanoparticle is not toxic. On the other hand, the in vitro studies showed that while ovarian stromal cells were still viable (82.04 ± 2.79%) after the treatment by 0.5 µM ORN, the same treatment yielded 95.43 ± 3.89% toxicity and cell death in the cancer cells. In conclusion, our results showed that our novel PDT procedure could be a promising strategy to destroy leukemia cells in ovarian tissue fragments allowing safe transplantation in cancer survivors.

The safety and efficiency of photodynamic therapy for the treatment of osteosarcoma: A systematic review of in vitro experiment and animal model reports

BACKGROUND

Osteosarcoma (OS) is an aggressive malignant bone tumour with high mortality. A poor prognosis is noted in patients with distal metastases or multidrug resistance. As an emerging antitumor strategy, photodynamic therapy (PDT) mediated by visible and near infrared light has attracted intensive attention given its target selectivity, remote controllability, minimal or non-invasive features. However, PDT also has obvious limitations. Specifically, due to the limited penetration of light, it is mainly used in the clinical treatment of superficial malignant tumours, such as musculoskeletal sarcomas and melanoma, but it has not been applied to the clinical treatment of deep malignant bone tumours except for a very small number of experiments on deep canine OS models.

MATERIALS AND METHODS

We searched for studies that focused on the effectiveness and safety of PDT for OS based on in vitro experiments and animal models in the last decade. A systematic search was conducted using electronic databases, including PubMed, ClinicalTrials.gov, and the Cochrane Library.

INCLUSION CRITERIA

(1) original research articles about PDT for OS; (2) articles in English; (3) in vitro or animal model research; and (4) detailed information, including cell name, fluence, irradiation wavelength, time of incubation with PS, duration between PS treatment and irradiation, and duration between irradiation and viability assays.

EXCLUSION CRITERIA

(1) study was a review/systemic review article, patent, letter, or conference abstract/paper; (2) articles were not published in English; (3) studies containing overlapping or insufficient data.

RESULTS

We identified 201 publications, and 44 articles met the inclusion criteria and were included in the synthesis. Unfortunately, there are no relevant clinical reports of the use of PDT in the treatment of human OS. In these studies, 8 studies only employed in vivo experiments to evaluate the efficiency of PDT in an OS animal model, 19 studies exclusively performed in vitro viability assays of cells treated with PDT under different conditions, and 17 studies included in vitro cell experiments and in vivo animal OS models to evaluate the effect of PDT on OS in vivo and in vitro. All studies have shown that PDT is cytotoxic to OS cells or can inhibit the growth of OS in heterologous or homologous animal OS models but exhibits minimal cytotoxicity at a certain range of dosages.

CONCLUSION

Based on this systematic review, PDT can eradicate OS cells in cell culture and there is some evidence for efficacy in animal models. However, the ability for PDT to control human OS is unclear, the animal and human reports do not show evidence of human OS control, they just do show feasibility. The major issues concerning the potential for treatment of osteosarcoma with PDT are that adequate light should be transmitted to tumor loci and if the disease is caught before metastasis and irradiation of tumor sites is feasible, curative potential is there. Otherwise, PDT may be mainly palliative. To determine whether PDT can safely and efficiently be used in the clinical treatment of OS, many preclinical orthotopic animal OS models and OS models of multiple systemic metastases must be performed and interstitial PDT or intraoperative PDT may be a good and potential candidate for human OS treatment. If these problems can be well solved, PDT may be a potentially effective strategy for the treatment of OS patients.

The effect of hypoxia on photodynamic therapy with 5-aminolevulinic acid in malignant gliomas

BACKGROUND

Glioblastoma (GBM) is a high-grade, poor prognosis tumor that is resistant to standard treatment. The presence of a small number of glioma stem cells (GSCs) surviving in the harsh microenvironment is responsible for their refractoriness. This study aimed to investigate the effect of a hypoxic environment on the sensitivity of GSCs to photodynamic therapy with 5-aminolevulinic acid (ALA-PDT).

MATERIALS AND METHODS

Six human GSC lines, Mesenchymal types HGG13, HGG30, HGG1123, and Proneural types HGG146, HGG157, HGG528, were divided into two groups: normoxia (O₂ 21%)-cultured cells (Normoxia-GSCs), and hypoxia (O₂ 5%)-cultured cells (Hypoxia-GSCs). To compare the effects of different oxygen partial pressures on photoporphyrin Ⅸ (PpⅨ) biosynthetic activity, PpⅨ biosynthetic enzyme and transporter expression levels were examined by qRT-PCR; the intracellular PpⅨ concentration was determined using flow cytometry. Additionally, the sensitivity of these two groups of cells to ALA-PDT was evaluated in vitro.

RESULTS

Hypoxia-GSCs showed higher mRNA levels of FECH (ferrochelatase), which is required for iron synthesis to convert PpⅨ to heme, compared with Normoxia-GSCs. Flow cytometry revealed that the accumulation of PpⅨ in Hypoxia-GSCs reduced upon incubation with ALA. However, Hypoxia-GSCs showed less reduction in sensitivity to ALA-PDT than Normoxia-GSCs.

CONCLUSION

Hypoxia-GSCs had lower intracellular PpⅨ accumulation than Normoxia-GSCs due to increased gene expression of FECH, and that their sensitivity to ALA-PDT was reduced less, despite accumulating lower concentrations of PpⅨ. ALA-PDT is a potentially effective therapy for hypoxia-tolerant GSCs that exist in hypoxia at 5% oxygen concentration.

High reactive oxygen species produced from fluorescence carbon dots for anticancer and photodynamic therapies: A review

High-photoluminescence carbon dots (CDs) were synthesized from various sources and various methods using two approaches, namely bottom up and top down, with emission-dependent excitation wavelength. Electronic transition from the higher-occupied molecular orbital (HOMO) state to the lowest-unoccupied molecular orbital(LUMO) state, surface defect states, wider excitation spectrum, higher quantum yield, efficient energy transfer, and element doping affected the fluorescence properties of CDs. Using 102 references listed in this review, the authors studied the relationship between fluorescence mechanism and reactive oxygen species (ROS) produced for photodynamic therapy (PDT) and materials anticancer applications. We described how the radical atom or ROS work as anticancer therapy and PDT and described the chemical reaction of high-resolution fluorescence CDs. We summarized experimental techniques that are used for producing CDs and discussed their characteristics. Finally, conclusions and future prospects in this field are also discussed. The important characteristics of CD-based design for high ROS may usher in new prospects and challenges for high efficiency and stability of PDT and anticancer therapy. In conclusion, we have provided perspectives and challenges of the future development of CD s.

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

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

Global research trends on photodynamic therapy in endodontics: A bibliometric analysis

BACKGROUND

Photodynamic therapy (PDT) is an adjunctive treatment that aims to inactivate microorganisms through an oxidative reaction produced by irradiating a photosensitizing agent. The quest for improved root canal disinfection has sought supplementary methods when performing chemomechanical procedures. From this perspective, PDT protocols were proposed as an auxiliary approach in endodontics. Thus, the aim of this study was to investigate publication metrics and research trends related to this scope.

METHODS

This review is reported in accordance with the PRISMA 2020 recommendations. Two blinded and independent reviewers systematically searched five electronic databases until December 2021. The acquired bibliometric parameters were analyzed through descriptive statistics and graphical mappings with VOSViewer software.

RESULTS

The search retrieved 342 studies from 84 journals originating from 33 countries. About 85% of the included studies were published over the last decade. Most of the available evidence is laboratory-based (74.5%), and the main clinical outcomes evaluated were microbiological load reduction and postoperative pain. Mayram Pourhajibagher is the researcher with the most publications as the first author (n = 16). Tehran University of Medical Sciences carried out the highest number of studies (n = 29), and Photodiagnosis and Photodynamic Therapy is the journal that most published on the theme (n = 111).

CONCLUSIONS

This bibliometric analysis mapped and discussed the scientific progress and publication metrics in PDT in endodontic research. Additionally, future perspectives were highlighted and should focus on discovering new photosensitizer agents, standardizing optimal photoactivation protocols, and conducting more clinical-oriented research.

Sonopharmacology: controlling pharmacotherapy and diagnosis by ultrasound-induced polymer mechanochemistry

Active pharmaceutical ingredients are the most consequential and widely employed treatment in medicine although they suffer from many systematic limitations, particularly off-target activity and toxicity. To mitigate these effects, stimuli-responsive controlled delivery and release strategies for drugs are being developed. Fueled by the field of polymer mechanochemistry, recently new molecular technologies enabled the emergence of force as an unprecedented stimulus for this purpose by using ultrasound. In this research area, termed sonopharmacology, mechanophores bearing drug molecules are incorporated within biocompatible macromolecular scaffolds as preprogrammed, latent moieties. This review presents the novelties in controlling drug activation, monitoring, and release by ultrasound, while discussing the limitations and challenges for future developments.

How to Manage a Patient with Ocular Metastases?

Ocular metastases are the most frequent ocular malignant tumors; their prevalence is estimated around 5-10% and is even higher in patients with breast or lung cancer. They represent various clinical situations, but they share the same hierarchical multidisciplinary therapeutic challenge with respect to the way systemic and local therapies should be selected in combination or sequentially in the personalized medical history of a patient. The challenges include tumor control, eye preservation, and the minimization of iatrogenic damage to sensitive tissues surrounding the tumor in order to preserve vision. These aims should further contribute to maintaining quality of life in patients with metastases. Many patients with choroidal metastases have systemic molecular treatment for their primary tumor. However, secondary resistance to systemic treatment is common and may ultimately be associated with cancer relapse, even after an initial response. Therefore, it makes sense to propose local treatment concomitantly or after systemic therapy to provide a more sustainable response. The aim of this review is to present current therapeutic strategies in ocular metastases and discuss how to tailor the treatment to a specific patient.

Photodynamic therapy for malignant brain tumors in children and young adolescents

Photodynamic therapy (PDT) targets tumor cell remnants after resection. Here, we evaluated the feasibility of PDT for malignant brain tumors in children and young adolescents. This was a single-center, non-randomized, phase I/II clinical study. The primary endpoints were the safety of treatment with talaporfin sodium (TS) (phase I) and overall survival (OS) after PDT (phase II). The secondary endpoint was progression-free survival (PFS) after PDT. The TS dose was determined by dose escalation from 10 to 20 to 40 mg/m² for every three cases starting from the initial enrolled case. Eight patients with a mean age of 170.2 months (129-214 months) at the time of PDT received nine procedures with a mean follow-up duration of 16.8 months (1-42 months) after PDT. Histopathological diagnoses included supratentorial anaplastic ependymoma (n = 2), anaplastic astrocytoma (n = 1), diffuse midline glioma with H3K27M mutation (n = 1), glioblastoma (n = 3), and pediatric high-grade glioma (n = 1). The outcome was survival in five patients and death in three patients. Recurrence occurred in six of the eight patients; the remaining two were recurrence-free after PDT. Therefore, OS and PFS were calculated as 21 and 6 months, respectively. Seizures and fevers, which were likely surgery-related symptoms, were commonly observed. Photosensitive skin rashes or liver dysfunction, which are common adverse effects in adults, were not observed. Our results showed that TS can be used safely in children at doses comparable to those used in adults, as there was no major complication associated with TS administration. However, we cannot make a definitive conclusion about the efficacy of PDT because of the small number of participants. Accumulating cases was difficult because of the rarity of pediatric brain tumors and the difficulty in making a preoperative differential diagnosis, considering the wide range of histopathological findings. Moreover, the psychological stress associated with light-shielding management in pediatric patients was more severe than initially expected. In conclusion, TS at doses comparable to those used in adults may be safe for use in children and young adolescents between the ages of 6 and 20 years. However, further studies are needed to clarify its efficacy.

Photodynamic therapy improves the clinical efficacy of advanced colorectal cancer and recruits immune cells into the tumor immune microenvironment

OBJECTIVE

Although photodynamic therapy (PDT) has been proven effective in various tumors, it has not been widely used as a routine treatment for colorectal cancer (CRC), and the characteristics of changes in the tumor microenvironment (TME) after PDT have not been fully elucidated. This study evaluated the efficacy of PDT in patients with advanced CRC and the changes in systemic and local immune function after PDT.

METHODS

Patients with stage III-IV CRC diagnosed in our hospital from November 2020 to July 2021 were retrospectively analyzed to compare the survival outcomes among each group. Subsequently, short-term efficacy, systemic and local immune function changes, and adverse reactions were assessed in CRC patients treated with PDT.

RESULTS

A total of 52 CRC patients were enrolled in this retrospective study from November 2020 to July 2021, and the follow-up period ended in March 2022. The overall survival (OS) of the PDT group was significantly longer than that of the non-PDT group (p=0.006). The objective response rate (ORR) and disease control rate two months after PDT were 44.4% and 88.9%, respectively. Differentiation degree (p=0.020) and necrosis (p=0.039) are two crucial factors affecting the short-term efficacy of PDT. The systemic immune function of stage III patients after PDT decreased, whereas that of stage IV patients increased. Local infiltration of various immune cells such as CD3+ T cells, CD4+ T cells, CD8+ T cells, CD20+ B cells and macrophages in the tumor tissue were significantly increased. No severe adverse reactions associated with PDT were observed.

CONCLUSION

PDT is effective for CRC without significant side effects according to the available data. It alters the TME by recruiting immune cells into tumor tissues.

Topical methylene blue nanoformulation for the photodynamic therapy of acne vulgaris

Acne vulgaris is a common skin disease caused by multifactorial reasons involving excessive sebum secretion and inflammation by Cutibacterium acnes (C. acnes). Various conventional therapies are available for the treatment of acne vulgaris; however, topical photodynamic therapy (PDT) has attracted much attention because of its great potential for sebum-reducing, anti-inflammatory, and antimicrobial activities. Although 5-aminolevulinic acid (ALA) has been broadly used as a photosensitizer for topical PDT, it has several limitations such as long incubation time, pain, and post-inflammatory hyperpigmentation. Here, we report a biocompatible nanoformulation consisting of methylene blue and salicylic acid (MBSD), as a potent PDT and acne therapeutics, enclosed within oleic acid. Photoactivated MBSD showed antimicrobial activity against C. acnes along with long-term stability. When 24 patients with acne were treated with MBSD and light irradiation 5 times at 1-week intervals, MBSD-based PDT exhibited a remarkable reduction in acne lesions and sebum production. In addition, the therapeutic procedure was painless and safe, without any adverse events. Therefore, MBSD is a promising topical PDT agent for biocompatible, safe, and effective acne treatment.

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

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

W18O49@EP nanoparticles improve the anti-tumor effect of radiotherapy and photodynamic therapy by avoiding the limitation of hypoxia

Insufficient oxygen supply at the tumor site and hypoxia caused during tumor treatment lead to a poor therapeutic effect and poor prognosis. Therefore, effectively overcoming the problem of hypoxia in tumors and avoiding hypoxia that compromises the efficacy of the treatment could improve the anti-tumor therapeutic effect. Thus, this study reports the ability of W18O49@EP nanoparticles to release reactive oxygen species (ROS) during the combined tumor radiotherapy (RT) and photodynamic therapy (PDT). The release of ROS by the nanoparticles during near infrared light (NIR) irradiation was demonstrated by in vitro and in vivo experiments, realizing an effective PDT without inducing hypoxia. Indeed, the ROS did not derive from the oxygen in the tumor microenvironment but they were released by the nanoparticles. Thus, ROS could improve the therapeutic effect of RT avoiding the problem of hypoxia after RT. Hence, W18O49@EP nanoparticles greatly improved the anti-tumor effect due to their effectiveness despite the insufficient oxygen supply and hypoxia caused by traditional RT and PDT.

Ablation efficacy of 5-aminolevulinic acid-mediated photodynamic therapy on human glioma stem cells

BACKGROUND

Cancer cells with stem cell-like features are generally more resistant to chemotherapy and radiotherapy than differentiated tumor cells. Thus, these cells tend to increase the propensity for tumor recurrence and metastasis. This study investigated the efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) in destructing glioma stem cells (GSCs), including the mesenchymal subtype (MES-GSCs) demonstrated to have the lowest radio- and chemosensitivity.

METHODS

Five high-grade glioma (HGG) GSC lines and derived differentiated glioma cell (DGC) lines were examined for protoporphyrin-IX (PpIX) expression using fluorescence-activated cell sorting (FACS) and then assessed for ALA-PDT sensitivity using cell viability assays. MES-GSCs surviving ALA-PDT were then isolated and evaluated for stem cell and mesenchymal marker expression levels (CD44, ALDH1A3, KLF4, nestin) by qRT-PCR. The ability of these surviving cells to form tumors was then examined using colony forming and by xenograft tumor assays in athymic mice. Finally, the relationship between PpIX expression level (high versus low) and ALA-PDT sensitivity was examined by FACS and colony forming assays.

RESULTS

ALA-PDT was effective against all GSC lines including MES-GSCs. MES-GSC lines exhibited higher PpIX expression than derived DGCs. Surviving MES-GSCs demonstrated lower stem cell marker expression and tumor forming potential than naive MES-GSCs. Higher PpIX production capacity by MES-GSCs was associated with greater colony forming ability, and ALA-PDT was more effective against MES-GSCs with greater PpIX accumulation.

CONCLUSION

ALA-PDT may be clinically effective against HGG by targeting GSCs, including MES-GSCs.

Insight into the Prospects for Tumor Therapy Based on Photodynamic Immunotherapy

Malignancy is one of the common diseases with high mortality worldwide and the most important obstacle to improving the overall life expectancy of the population in the 21st century. Currently, single or combined treatments, including surgery, chemotherapy, and radiotherapy, are still the mainstream regimens for tumor treatment, but they all present significant side effects on normal tissues and organs, such as organ hypofunction, energy metabolism disorders, and various concurrent diseases. Based on this, theranostic measures for the highly selective killing of tumor cells have always been a hot area in cancer-related fields, among which photodynamic therapy (PDT) is expected to be an ideal candidate for practical clinical application due to its precise targeting and excellent safety performance, so-called PDT refers to a therapeutic method mainly composed of photosensitizers (PSs), laser light, and reactive oxygen species (ROS). Photoimmunotherapy (PIT), a combination of PDT and immunotherapy, can induce systemic antitumor immune responses and inhibit continuing growth and distant metastasis of residual tumor cells, demonstrating a promising application prospect. This article reviews the types of immune responses that occur in the host after PDT treatment, including innate and adaptive immunity. To further help PIT-related drugs improve their pharmacokinetic properties and bioavailability, we highlight the potential improvement of photodynamic immunotherapy from three aspects: immunostimulatory agents, tumor-associated antigens (TAAs) as well as different immune cells. Finally, we focus on recent advances in various strategies and shed light on their corresponding mechanisms of immune activation and possible clinical applications such as cancer vaccines. Having discovered the inherent potential of PDT and the mechanisms that PDT triggers host immune responses, a variety of immunotherapeutic strategies have been investigated in parallel with approaches to improve PDT efficiency. However, it remains to be further elucidated under what conditions the immune effect induced by PDT can achieve tumor immunosuppression and to what extent PDT-induced antitumor immunity will lead to complete tumor rejection. Currently, PIT presents several outstanding intractable challenges, such as the aggregation ability of PSs locally in tumors, deep tissue penetration ability of laser light, immune escape, and biological toxicity, and it is hoped that these issues raised will help to point out the direction of preclinical research on PIT and accelerate its transition to clinical practice.

Aza-BODIPY based carbonic anhydrase IX: Strategy to overcome hypoxia limitation in photodynamic therapy

Hypoxia caused by photodynamic therapy (PDT) is a major hurdle to cancer treatment since it can promote recurrence and progression by activating angiogenic factors, lowering therapeutic efficacy dramatically. In this work, AZB-I-CAIX₂ was developed as a carbonic anhydrase IX (CAIX)-targeting NIR photosensitizer that can overcome the challenge by utilizing a combination of CAIX knockdown and PDT. AZB-I-CAIX₂ showed a specific affinity to CAIX-expressed cancer cells and enhanced photocytotoxicity compared to AZB-I-control (the molecule without acetazolamide). Moreover, selective detection and effective cell cytotoxicity of AZB-I-CAIX₂ by PDT in hypoxic CAIX-expressed murine cancer cells were achieved. Essentially, AZB-I-CAIX₂ could minimize tumor size in the tumor-bearing mice compared to that in the control groups. The results suggested that AZB-I-CAIX₂ can improve therapeutic efficiency by preventing PDT-induced hypoxia through CAIX inhibition.

Effect of Substituents on the Photodynamic Action of Anthraquinones: EPR, Computational and In Vitro Studies

Anthraquinone class of compounds possesses a broad spectrum of therapeutic applications. Cancer cell targeting ability, together with photogeneration of reactive oxygen species, renders anthraquinones an interesting class of photosensitizers for photodynamic therapy (PDT). Screening of newer compounds for better singlet oxygen generation is of current interest to improve the practical usability in PDT. In this study, we investigate the photodynamic activity of nine commercially available anthraquinones, using EPR spectroscopy and computational techniques, to identify the role of substituents on singlet oxygen yield. Three anthraquinone derivatives, 1,5-diaminoanthraquinone, 15-dihydroxyanthraquinone and 1,2,7-trihydroxyanthraquinone, showed highest singlet oxygen quantum yield (0.21, 0.18 and 0.15, respectively) relative to Rose Bengal. Time-dependent density functional theory calculations indicate the singlet oxygen quantum yield of anthraquinones inversely correlate well with the excited singlet-triplet (S1-T1) energy gap. Electron-donating substituents present at positions 1, 2 and 5 of anthraquinone seem to reduce the S1-T1 energy gap, facilitating inter-system crossing and the production of singlet oxygen. This would greatly aid in the design of newer anthraquinone-based photosensitizers. This study also highlights the suitability of 1,5-diaminoanthraquinone for PDT applications as demonstrated by in vitro experiments of photoinduced DNA cleavage and photocytotoxicity in Dalton's lymphoma ascites.