Sinoporphyrin sodium is a promising sensitizer for photodynamic and sonodynamic therapy in glioma

Photodynamic and sonodynamic therapy synergy: mechanistic insights and cellular responses against glioblastoma multiforme

Glioblastoma multiforme (GBM), the most aggressive form of brain cancer, poses substantial challenges to effective treatment due to its complex and infiltrative nature, making it difficult to manage. Photodynamic therapy (PDT) and sonodynamic therapy (SDT), have emerged as promising individual treatment options against GBM due to their least-invasive approach. However, both PDT and SDT have drawbacks that require careful consideration. A combination therapy using light and sound waves has gained attention, offering new avenues to overcome challenges from individual therapies. Sono-photodynamic therapy (SPDT) has been used against various tumours. Researchers are considering SPDT as a favourable alternative to the conventional therapies for GBM. SPDT offers complementary mechanisms of action, including the production of ROS, disruption of cellular structures, and induction of apoptosis, leading to enhanced tumour cell death. This review gives an insight about PDT/SDT and their limitations in GBM treatment and the need for combination therapy. We try to unveil the process of SPDT and explore the mechanism behind improved SPDT-meditated cell death in GBM cells by focusing on the ROS-mediated cell response occurring as a result of SPDT and discussing current modifications in the existing sensitisers for their optimal use in SPDT for GBM therapy.

The Implication of Photodynamic Therapy Applied to the Level of Tumor Resection on Postoperative Cerebral Edema and Intracranial Pressure Changes in Gliomas

AIM

The aim of our study was to explore the factors influencing cerebral edema and intracranial pressure in glioblastoma multiforme (GBM) patients who undergo photodynamic therapy (PDT) after resection.

APPROACH

This was a retrospective controlled study of GBM patients treated with PDT-assisted resections of varying scope from May 2021 to August 2023. The baseline clinical data, cerebral edema volumes, intracranial pressure values, and imaging data of the GBM patients were collected for statistical analysis.

RESULTS

A total of 56 GBM patients were included. Thirty of the patients underwent gross total resection (GTR), and the other 26 patients underwent subtotal resection (STR). We found that the cerebral edema volume and the mean intracranial pressure in patients who underwent GTR were lower than those in patients who underwent STR. Moreover, univariate analysis showed that the scope of tumor resection was an independent factor affecting cerebral edema and intracranial pressure after PDT.

CONCLUSIONS

Compared with STR, PDT combined with GTR significantly reduced postoperative brain edema volume and intracranial pressure in GBM patients.

Photodynamic therapy and associated targeting methods for treatment of brain cancer

Brain tumors, including glioblastoma multiforme, are currently a cause of suffering and death of tens of thousands of people worldwide. Despite advances in clinical treatment, the average patient survival time from the moment of diagnosis of glioblastoma multiforme and application of standard treatment methods such as surgical resection, radio- and chemotherapy, is less than 4 years. The continuing development of new therapeutic methods for targeting and treating brain tumors may extend life and provide greater comfort to patients. One such developing therapeutic method is photodynamic therapy. Photodynamic therapy is a progressive method of therapy used in dermatology, dentistry, ophthalmology, and has found use as an antimicrobial agent. It has also found wide application in photodiagnosis. Photodynamic therapy requires the presence of three necessary components: a clinically approved photosensitizer, oxygen and light. This paper is a review of selected literature from Pubmed and Scopus scientific databases in the field of photodynamic therapy in brain tumors with an emphasis on glioblastoma treatment.

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

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

Applications of Focused Ultrasound for the Treatment of Glioblastoma: A New Frontier

Glioblastoma (GBM) is an aggressive primary astrocytoma associated with short overall survival. Treatment for GBM primarily consists of maximal safe surgical resection, radiation therapy, and chemotherapy using temozolomide. Nonetheless, recurrence and tumor progression is the norm, driven by tumor stem cell activity and a high mutational burden. Focused ultrasound (FUS) has shown promising results in preclinical and clinical trials for treatment of GBM and has received regulatory approval for the treatment of other neoplasms. Here, we review the range of applications for FUS in the treatment of GBM, which depend on parameters, including frequency, power, pulse duration, and duty cycle. Low-intensity FUS can be used to transiently open the blood-brain barrier (BBB), which restricts diffusion of most macromolecules and therapeutic agents into the brain. Under guidance from magnetic resonance imaging, the BBB can be targeted in a precise location to permit diffusion of molecules only at the vicinity of the tumor, preventing side effects to healthy tissue. BBB opening can also be used to improve detection of cell-free tumor DNA with liquid biopsies, allowing non-invasive diagnosis and identification of molecular mutations. High-intensity FUS can cause tumor ablation via a hyperthermic effect. Additionally, FUS can stimulate immunological attack of tumor cells, can activate sonosensitizers to exert cytotoxic effects on tumor tissue, and can sensitize tumors to radiation therapy. Finally, another mechanism under investigation, known as histotripsy, produces tumor ablation via acoustic cavitation rather than thermal effects.

Nanosensitizers for sonodynamic therapy for glioblastoma multiforme: current progress and future perspectives

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor, and it is associated with poor prognosis. Its characteristics of being highly invasive and undergoing heterogeneous genetic mutation, as well as the presence of the blood-brain barrier (BBB), have reduced the efficacy of GBM treatment. The emergence of a novel therapeutic method, namely, sonodynamic therapy (SDT), provides a promising strategy for eradicating tumors via activated sonosensitizers coupled with low-intensity ultrasound. SDT can provide tumor killing effects for deep-seated tumors, such as brain tumors. However, conventional sonosensitizers cannot effectively reach the tumor region and kill additional tumor cells, especially brain tumor cells. Efforts should be made to develop a method to help therapeutic agents pass through the BBB and accumulate in brain tumors. With the development of novel multifunctional nanosensitizers and newly emerging combination strategies, the killing ability and selectivity of SDT have greatly improved and are accompanied with fewer side effects. In this review, we systematically summarize the findings of previous studies on SDT for GBM, with a focus on recent developments and promising directions for future research.

Application of Self-Assembly Nanoparticles Based on DVDMS for Fenton-Like Ion Delivery and Enhanced Sonodynamic Therapy

Upon harnessing low-intensity ultrasound to activate sonosensitizers, sonodynamic therapy (SDT) induces cancer cell death through the reactive oxygen species (ROS) mediated pathway. Compared with photodynamic therapy (PDT), SDT possesses numerous advantages, including deeper tissue penetration, higher accuracy, fewer side effects, and better patient compliance. Sinoporphyrin sodium (DVDMS), a sonosensitizer approved by the FDA, has drawn abundant attention in clinical research, but there are some deficiencies. In order to further improve the efficiency of DVDMS, many studies have applied self-assembly nanotechnology to modify it. Furthermore, the combined applications of SDT/chemodynamic therapy (CDT) have become a research hotspot in tumor therapy. Therefore, we explored the self-assembly of nanoparticles based on DVDMS and copper to combine SDT and CDT. A cost-effective sonosensitizer was synthesized by dropping CuCl2 into the DVDMS solution with the assistance of PVP. The results revealed that the nanostructures could exert excellent treatment effects on tumor therapy and perform well for PET imaging, indicating the potential for cancer theranostics. In vitro and in vivo experiments showed that the nanoparticles have outstanding biocompatibility, higher ROS production efficiency, and antitumor efficacy. We believe this design can represent a simple approach to combining SDT and CDT with potential applications in clinical treatment and PET imaging.

Hematoporphyrin Is a Promising Sensitizer for Dual-Frequency Sono-photodynamic Therapy in Mice Breast Cancer

Background: The combination of sonodynamic and photodynamic therapy (SPDT) may be a new hopeful non-invasive method for cancer treatment, which incorporates a combination of low-intensity ultrasound, laser radiation, and a sensitizer agent. Objectives: This study aimed at evaluating the effects of hematoporphyrin (HP)-mediated SPDT (dual-frequency ultrasound and laser radiation) in the management of mice breast adenocarcinoma. Methods: One hundred and thirty-two female mice with implanted tumors were divided into 22 groups, including sham, laser, 4 groups of dual-frequency ultrasound/laser radiation, 8 groups of HP-mediated SPDT (2.5 and 5 mg/kg), and 8 groups of HP encapsulated in mesoporous silica nanoparticles (HP-MSNs)-mediated SPDT. The sensitizer was administered by intraperitoneal injection and after a 24-hour delay, tumor grafted mice were treated with a combination of dual-frequency ultrasound and laser light. The tumor growth factors were used to assess the treatment outcome. Results: The results indicated that HP or HP-MSNs-mediated SPDT had a delaying tumor growth effect. In the groups treated with dual-frequency ultrasound and laser radiation, the maximum tumor growth inhibition (TGI) ratio was 47.5%, while the maximum TGI ratio in the SPDT groups was 61.6%. The time of T2 and T5 in the case of HP-MSNs-mediated SPDT groups was increased compared with sham and that of HP-mediated SPDT groups (P < 0.05). The inhibition ratio on tumor growth increased in all SPDT groups at 12 days after the treatment. Analysis of experimental data demonstrates that this increase was not declined and persisted over 30 days of treatment. The results indicated that SPDT is effective in relative tumor volume when compared with the sham group (339.1 ± 161 and 1510.8 ± 160, respectively). HP or HP-MSNs-mediated SPDT groups had Grade I (low), while others had Grade III (high) malignancy in the histological study of mice breast adenocarcinoma. Conclusions: The results revealed that when sensitized by dual-frequency SPDT, hematoporphyrin (with and without MSNs), has a promising effect at delaying tumor growth on mice breast cancer. Therefore, it can be appreciated that careful selection of the sensitizer with SPDT will play an eminent role in the success of cancer therapies.

Progress in Nanocarriers Codelivery System to Enhance the Anticancer Effect of Photodynamic Therapy

Photodynamic therapy (PDT) is a promising anticancer noninvasive method and has great potential for clinical applications. Unfortunately, PDT still has many limitations, such as metastatic tumor at unknown sites, inadequate light delivery and a lack of sufficient oxygen. Recent studies have demonstrated that photodynamic therapy in combination with other therapies can enhance anticancer effects. The development of new nanomaterials provides a platform for the codelivery of two or more therapeutic drugs, which is a promising cancer treatment method. The use of multifunctional nanocarriers for the codelivery of two or more drugs can improve physical and chemical properties, increase tumor site aggregation, and enhance the antitumor effect through synergistic actions, which is worthy of further study. This review focuses on the latest research progress on the synergistic enhancement of PDT by simultaneous multidrug administration using codelivery nanocarriers. We introduce the design of codelivery nanocarriers and discuss the mechanism of PDT combined with other antitumor methods. The combination of PDT and chemotherapy, gene therapy, immunotherapy, photothermal therapy, hyperthermia, radiotherapy, sonodynamic therapy and even multidrug therapy are discussed to provide a comprehensive understanding.

Sonodynamic therapy for gliomas

INTRODUCTION

Glioma remains incurable and a life limiting disease with an urgent need for effective therapies. Sonodynamic therapy (SDT) involves systemic delivery of non-toxic chemical agents (sonosensitizers) that accumulate in tumor cells or environment and are subsequently activated by exposure to low-frequency ultrasound to become cytotoxic agents. Herein, we discuss proposed mechanisms of action of SDT and provide recommendation for future research and clinical applications of SDT for gliomas.

METHODS

Review of literature of SDT in glioma cell cultures and animal models published in Pubmed/MEDLINE before January, 2021.

RESULTS

Different porphyrin and xanthene derivatives have proven to be effective sonosensitizers. Generation of reactive oxygen species and free radicals from water pyrolysis or sonosensitizers, or physical destabilization of cell membrane, have been identified as mechanisms of SDT leading to cell death. Numerous studies across glioma cell lines using various sonosensitizers and ultrasound parameters have documented tumoricidal effects of SDT. Studies in small animal glioma xenograft models have also consistently documented that SDT is associated with improved tumor control and longer survival of animals treated with SDT while avoiding damage of surrounding brain. There are no clinical trials completed to date regarding safety and efficacy of SDT in patients harboring gliomas, but some are beginning.

CONCLUSIONS

Pre-clinical studies cell cultures and animal models indicate that SDT is a promising treatment approach for gliomas. Further studies should define optimal sonication parameters and sonosensitizers for gliomas. Clinical trials of SDT in patients harboring gliomas and other malignant brain tumors are currently underway.

Research progress of berberine mediated photodynamic therapy

Berberine (BBR) is a plant secondary metabolite that has been used in photodynamic therapy (PDT) in the last few decades. The present review aimed to discuss the research progress of BBR-mediated photodynamic actions. The following key words were searched in several databases: 'Berberine' combined with 'photodynamic therapy', 'sonodynamic therapy (SDT)', 'ultraviolet', 'reactive oxygen' and 'singlet oxygen'. The results demonstrated that both type I and type II reactions participated in the photodynamic progression of BBR derivatives. In addition, the photochemical characteristics of BBR derivatives were affected by the polarity, pH and O2 content of solvents. DNA binding increases the lifespan of the photoexcited BBR state and generation of singlet oxygen (1O2). The chemical properties of substituents in different positions of the BBR skeleton are pivotal for its photochemical properties, particularly the methylenedioxy group at the C-2 and C-3 positions. BBR is a promising agent for mediating both PDT- and SDT-treated diseases, particularly in tumors. However, further studies are required to validate their biological effects. In addition, the molecular mechanisms underlying the antitumor effects of BBR-PDT remain unclear and warrant further investigation. The structural modification and targeted delivery of BBR have made it possible to broaden its applications; however, experimental verification is required. Overall, BBR acts as a sensitizer for PDT and has promising development prospects.

Design and Challenges of Sonodynamic Therapy System for Cancer Theranostics: From Equipment to Sensitizers

As a novel noninvasive therapeutic modality combining low-intensity ultrasound and sonosensitizers, sonodynamic therapy (SDT) is promising for clinical translation due to its high tissue-penetrating capability to treat deeper lesions intractable by photodynamic therapy (PDT), which suffers from the major limitation of low tissue penetration depth of light. The effectiveness and feasibility of SDT are regarded to rely on not only the development of stable and flexible SDT apparatus, but also the screening of sonosensitizers with good specificity and safety. To give an outlook of the development of SDT equipment, the key technologies are discussed according to five aspects including ultrasonic dose settings, sonosensitizer screening, tumor positioning, temperature monitoring, and reactive oxygen species (ROS) detection. In addition, some state-of-the-art SDT multifunctional equipment integrating diagnosis and treatment for accurate SDT are introduced. Further, an overview of the development of sonosensitizers is provided from small molecular sensitizers to nano/microenhanced sensitizers. Several types of nanomaterial-augmented SDT are in discussion, including porphyrin-based nanomaterials, porphyrin-like nanomaterials, inorganic nanomaterials, and organic-inorganic hybrid nanomaterials with different strategies to improve SDT therapeutic efficacy. There is no doubt that the rapid development and clinical translation of sonodynamic therapy will be promoted by advanced equipment, smart nanomaterial-based sonosensitizer, and multidisciplinary collaboration.

Sonodynamic Therapy for the Treatment of Intracranial Gliomas

High-grade gliomas are the most common and aggressive malignant primary brain tumors. Current therapeutic schemes include a combination of surgical resection, radiotherapy and chemotherapy; even if major advances have been achieved in Progression Free Survival and Overall Survival for patients harboring high-grade gliomas, prognosis still remains poor; hence, new therapeutic options for malignant gliomas are currently researched. Sonodynamic Therapy (SDT) has proven to be a promising treatment combining the effects of low-intensity ultrasound waves with various sound-sensitive compounds, whose activation leads to increased immunogenicity of tumor cells, increased apoptotic rates and decreased angiogenetic potential. In addition, this therapeutic technique only exerts its cytotoxic effects on tumor cells, while both ultrasound waves and sensitizing compound are non-toxic per se. This review summarizes the present knowledge regarding mechanisms of action of SDT and currently available sonosensitizers and focuses on the preclinical and clinical studies that have investigated its efficacy on malignant gliomas. To date, preclinical studies implying various sonosensitizers and different treatment protocols all seem to confirm the anti-tumoral properties of SDT, while first clinical trials will soon start recruiting patients. Accordingly, it is crucial to conduct further investigations regarding the clinical applications of SDT as a therapeutic option in the management of intracranial gliomas.