Advances in photodynamic therapy for the treatment of head and neck cancers

Photodynamic Therapy: A Novel Approach for Head and Neck Cancer Treatment with Focusing on Oral Cavity

Oral cancers, specifically oral squamous cell carcinoma (OSCC), pose a significant global health challenge, with high incidence and mortality rates. Conventional treatments such as surgery, radiotherapy, and chemotherapy have limited effectiveness and can result in adverse reactions. However, as an alternative, photodynamic therapy (PDT) has emerged as a promising option for treating oral cancers. PDT involves using photosensitizing agents in conjunction with specific light to target and destroy cancer cells selectively. The photosensitizers accumulate in the cancer cells and generate reactive oxygen species (ROS) upon exposure to the activating light, leading to cellular damage and ultimately cell death. PDT offers several advantages, including its non-invasive nature, absence of known long-term side effects when administered correctly, and cost-effectiveness. It can be employed as a primary treatment for early-stage oral cancers or in combination with other therapies for more advanced cases. Nonetheless, it is important to note that PDT is most effective for superficial or localized cancers and may not be suitable for larger or deeply infiltrating tumors. Light sensitivity and temporary side effects may occur but can be managed with appropriate care. Ongoing research endeavors aim to expand the applications of PDT and develop novel photosensitizers to further enhance its efficacy in oral cancer treatment. This review aims to evaluate the effectiveness of PDT in treating oral cancers by analyzing a combination of preclinical and clinical studies.

Quasi-intrinsic thiobase derivatives as potential targeted photosensitizers in two-photon photodynamic therapy

In this study, a set of potential quasi-intrinsic photosensitizers for two-photon photodynamic therapy (PDT) are proposed based on the unnatural 2-amino-8-(1'-β-ᴅ-2'-deoxyribofuranosyl)-imidazo[1,2-ɑ]-1,3,5-triazin-4(8H)-one (P), which is paired with the 6-amino-5-nitro-3-(1'-β-ᴅ-2'-deoxyribofuranosyl)-2(1H)-pyridone (Z) and can specifically recognize breast and liver cancer cells. Herein, the effects of sulfur substitution and electron-donating/electron-withdrawing groups on the photophysical properties in aqueous solution are systematically investigated. The one- and two-photon absorption spectra evidence that the modifications could result in red-shifted absorption wavelength and large two-photon absorption cross-section, which contributes to selective excitation and provides effective PDT for deep-seated tissues. To ensure the efficient triplet state population, the singlet-triplet energy gaps and spin-orbit coupling constants were examined, which is responsible for a rapid intersystem crossing rate. Furthermore, these thiobase derivatives are characterized by the long-lived T1 state and the large energy gap for radiationless transition to ensure the generation of cytotoxic singlet oxygen.

Progress and trends in photodynamic therapy research in oral science: A bibliometric analysis

BACKGROUND

Photodynamic therapy is garnering increasing attention in oral science. Despite its promising potential, further exploration is warranted to delve into the research paradigms and evolving trends within oral science. Therefore, this study aimed to conduct a comprehensive bibliometric analysis of photodynamic therapy in oral science (PDTOS), investigating research landscapes, identifying key contributors, analyzing collaborative networks, pinpointing emerging research directions, and exploring factors influencing high citations.

METHODS

Research and review articles in PDTOS were retrieved from the Web of Science Core Collection database up to December 31, 2023. The R package "bibliometrix" and VOSviewer were utilized for visualizing collaboration networks and keyword co-occurrence, alongside trend analysis. Negative binomial regression was used to model factors affecting citation counts.

RESULTS

A total of 2784 articles with significant international collaboration (23.14 %) were analyzed. Brazil, China, the USA, Iran, and Italy led in publications, with predominant USA-European collaborations. The University of Sao Paulo in Brazil was the most published institution in the field. Photodiagnosis and Photodynamic Therapy was the core journal in the field and has the highest number of publications. The main research fields included photodynamic therapy, antibacterial and anticancer treatment, management, and peri‑implant periodontitis, with a recent focus on peri‑implantitis. Factors such as international cooperation, funding, article age, type, author count, and references significantly influenced citations.

CONCLUSIONS

This research provided valuable insights into PDTOS trends and knowledge structures. These findings underscored a significant increase in the number of PDTOS publications, urging strengthened international cooperation. Emerging research has focused on peri‑implantitis and nano-photosensitizer materials. Authors should consider various citation-related factors in their research endeavors.

Advances in Medicine: Photodynamic Therapy

Over the past decades, medicine has made enormous progress, revolutionized by modern technologies and innovative therapeutic approaches. One of the most exciting branches of these developments is photodynamic therapy (PDT). Using a combination of light of a specific wavelength and specially designed photosensitizing substances, PDT offers new perspectives in the fight against cancer, bacterial infections, and other diseases that are resistant to traditional treatment methods. In today's world, where there is a growing problem of drug resistance, the search for alternative therapies is becoming more and more urgent. Imagine that we could destroy cancer cells or bacteria using light, without the need to use strong chemicals or antibiotics. This is what PDT promises. By activating photosensitizers using appropriately adjusted light, this therapy can induce the death of cancer or bacterial cells while minimizing damage to surrounding healthy tissues. In this work, we will explore this fascinating method, discovering its mechanisms of action, clinical applications, and development prospects. We will also analyze the latest research and patient testimonies to understand the potential of PDT for the future of medicine.

State of the Art in the Diagnosis and Assessment of Oral Malignant and Potentially Malignant Disorders: Present Insights and Future Outlook-An Overview

Oral Potentially Malignant Disorder (OPMD) is a significant concern for clinicians due to the risk of malignant transformation. Oral Squamous Cell Carcinoma (OSCC) is a common type of cancer with a low survival rate, causing over 200,000 new cases globally each year. Despite advancements in diagnosis and treatment, the five-year survival rate for OSCC patients remains under 50%. Early diagnosis can greatly improve the chances of survival. Therefore, understanding the development and transformation of OSCC and developing new diagnostic methods is crucial. The field of oral medicine has been advanced by technological and molecular innovations, leading to the integration of new medical technologies into dental practice. This study aims to outline the potential role of non-invasive imaging techniques and molecular signatures for the early detection of Oral Malignant and Potentially Malignant Disorders.

Detection of micro-plasma-induced exosomes secretion in a fibroblast-melanoma co-culture model

BACKGROUND

Melanoma is a highly aggressive tumor and a significant cause of skin cancer-related death. Timely diagnosis and treatment require identification of specific biomarkers in exosomes secreted by melanoma cells. In this study, label-free surface-enhanced Raman spectroscopy (SERS) method with size-matched selectivity was used to detect membrane proteins in exosomes released from a stimulated environment of fibroblasts (L929) co-cultured with melanoma cells (B16-F10). To promote normal secretion of exosomes, micro-plasma treatment was used to gently induce the co-cultured cells and slightly increase the stress level around the cells for subsequent detection using the SERS method.

RESULTS AND DISCUSSION

Firstly, changes in reactive oxygen species/reactive nitrogen species (ROS/RNS) concentrations in the cellular microenvironment and the viability and proliferation of healthy cells are assessed. Results showed that micro-plasma treatment increased extracellular ROS/RNS levels while modestly reducing cell proliferation without significantly affecting cell survival. Secondly, the particle size of secreted exosomes isolated from the culture medium of L929, B16-F10, and co-cultured cells with different micro-plasma treatment time did not increase significantly under single-cell conditions at short treatment time but might be changed under co-culture condition or longer treatment time. Third, for SERS signals related to membrane protein biomarkers, exosome markers CD9, CD63, and CD81 can be assigned to significant Raman shifts in the range of 943-1030 and 1304-1561 cm-1, while the characteristics SERS peaks of L929 and B16-F10 cells are most likely located at 1394/1404, 1271 and 1592 cm-1 respectively.

SIGNIFICANCE AND NOVELTY

Therefore, this micro-plasma-induced co-culture model provides a promising preclinical approach to understand the diagnostic potential of exosomes secreted by cutaneous melanoma/fibroblasts. Furthermore, the label-free SERS method with size-matched selectivity provides a novel approach to screen biomarkers in exosomes secreted by melanoma cells, aiming to reduce the use of labeling reagents and the processing time traditionally required.

Unleashing the power of porphyrin photosensitizers: Illuminating breakthroughs in photodynamic therapy

This comprehensive review provides the current trends and recent developments of porphyrin-based photosensitizers. We discuss their evolution from first-generation to third-generation compounds, including cutting-edge nanoparticle-integrated derivatives, and explores their pivotal role in advancing photodynamic therapy (PDT) for enhanced cancer treatment. Integrating porphyrins with nanoparticles represents a promising avenue, offering improved selectivity, reduced toxicity, and heightened biocompatibility. By elucidating recent breakthroughs, innovative methodologies, and emerging applications, this review provides a panoramic snapshot of the dynamic field, addressing challenges and charting prospects. With a focus on harnessing reactive oxygen species (ROS) through light activation, PDT serves as a minimally invasive therapeutic approach. This article offers a valuable resource for researchers, clinicians, and PDT enthusiasts, highlighting the potential of porphyrin photosensitizers to improve the future of cancer therapy.

Photoactive Parietin-loaded nanocarriers as an efficient therapeutic platform against triple-negative breast cancer

The application of photodynamic therapy has become more and more important in combating cancer. However, the high lipophilic nature of most photosensitizers limits their parenteral administration and leads to aggregation in the biological environment. To resolve this problem and deliver a photoactive form, the natural photosensitizer parietin (PTN) was encapsulated in poly(lactic-co-glycolic acid) nanoparticles (PTN NPs) by emulsification diffusion method. PTN NPs displayed a size of 193.70 nm and 157.31 nm, characterized by dynamic light scattering and atomic force microscopy, respectively. As the photoactivity of parietin is essential for therapy, the quantum yield of PTN NPs and the in vitro release were assessed. The antiproliferative activity, the intracellular generation of reactive oxygen species, mitochondrial potential depolarization, and lysosomal membrane permeabilization were evaluated in triple-negative breast cancer cells (MDA-MB-231 cells). At the same time, confocal laser scanning microscopy (CLSM) and flow cytometry were used to investigate the cellular uptake profile. In addition, the chorioallantoic membrane (CAM) was employed to evaluate the antiangiogenic effect microscopically. The spherical monomodal PTN NPs show a quantum yield of 0.4. The biological assessment on MDA-MB-231 cells revealed that free PTN and PTN NPs inhibited cell proliferation with IC50 of 0.95 µM and 1.9 µM at 6 J/cm2, respectively, and this can be attributed to the intracellular uptake profile as proved by flow cytometry. Eventually, the CAM study illustrated that PTN NPs could reduce the number of angiogenic blood vessels and disrupt the vitality of xenografted tumors. In conclusion, PTN NPs are a promising anticancer strategy in vitro and might be a tool for fighting cancer in vivo.

Nanotechnology for Dentistry: Prospects and Applications

In the XXI century, application of nanostructures in oral medicine has become common. In oral medicine, using nanostructures for the treatment of dental caries constitutes a great challenge. There are extensive studies on the implementation of nanomaterials to dental composites in order to improve their properties, e.g., their adhesive strength. Moreover, nanostructures are helpful in dental implant applications as well as in maxillofacial surgery for accelerated healing, promoting osseointegration, and others. Dental personal care products are an important part of oral medicine where nanomaterials are increasingly used, e.g., toothpaste for hypersensitivity. Nowadays, nanoparticles such as macrocycles are used in different formulations for early cancer diagnosis in the oral area. Cancer of the oral cavity-human squamous carcinoma-is the sixth leading cause of death. Detection in the early stage offers the best chance at total cure. Along with diagnosis, macrocycles are used for photodynamic mechanism-based treatments, which possess many advantages, such as protecting healthy tissues and producing good cosmetic results. Application of nanostructures in medicine carries potential risks, like long-term influence of toxicity on body, which need to be studied further. The introduction and development of nanotechnologies and nanomaterials are no longer part of a hypothetical future, but an increasingly important element of today's medicine.

Spotlight on porphyrins: Classifications, mechanisms and medical applications

Photodynamic therapy (PDT) and sonodynamic therapy (SDT) are non-invasive treatment methods with obvious inhibitory effect on tumors and have few side effects, which have been widely concerned and explored by researchers. Sensitizer is the main factor in determining the therapeutic effect of PDT and SDT. Porphyrins, a group of organic compounds widespread in nature, can be activated by light or ultrasound and produce reactive oxygen species. Therefore, porphyrins as sensitizers in PDT have been widely explored and investigated for many years. Herein, we summarize the classical porphyrin compounds and their applications and mechanisms in PDT and SDT. The application of porphyrin in clinical diagnosis and imaging is also discussed. In conclusion, porphyrins have good application prospects in disease treatment as an important part of PDT or SDT, and in clinical diagnosis and imaging.

Antitumor activity of photodynamic therapy with tetracationic derivative of synthetic bacteriochlorin in spheroid culture of liver and colon cancer cells

Efficient screening of photosensitizers (PS) as well as studying their photodynamic activity, especially PS excited in the near-infrared region, require informative in vitro models to adequately reflect the architecture, thickness, and intercellular interactions in tumors. In our study, we used spheroids formed from human colon cancer HCT-116 cells and liver cancer Huh7 cells to assess the phototoxicity of a new PS based on tetracationic derivative of synthetic bacteriochlorin (BC4). We optimized conditions for the irradiation regime based on the kinetics of BC4 accumulation in spheroids and kinetics of spheroid growth. Although PS accumulated more efficiently in HCT-116 cells, characterized by more aggressive growth and high proliferative potential, they were less susceptible to the photodynamic therapy (PDT) compared to the slower growing Huh7 cells. We also showed that 3D models of spheroids were less sensitive to BC4 than conventional 2D cultures with relatively identical kinetics of drug accumulation. Our findings suggest that BC4 is a perspective agent for photodynamic therapy against cancer cells.

Covalent organic polymer induces apoptosis of liver cancer cells via photodynamic and photothermal effects

The purpose of this study was to explore the photodynamic and photothermal effects of the supramolecular material Purp@COP and to test the anti-cancer effect on HepG2 cells in vitro.

MOF(Fe)-derived composites as a unique nanoplatform for chemo-photodynamic tumor therapy

Fe-based metal-organic frameworks (MOFs) can be used for chemodynamic therapy (CDT) for tumors due to their unique Fenton-like effects and porous and biodegradable nature. The adsorption and transport of small molecule drugs by their structure has attracted much attention. Herein, MnO₂@NH₂-MIL101(Fe)@Ce6-F127 nanoparticles (MNMCF NPs) were synthesized using a facile solvothermal strategy. The small molecule photosensitizer Ce6 was adsorbed by MOFs to improve the biocompatibility of Ce6 and give it high bioavailability when injected intravenously. When the MNMCF NPs reached the tumor site, Fe-based MOFs exhibited Fenton-like properties, producing ˙OH and showing CDT effects. MnO₂ could specifically respond to produce O₂ in a tumor microenvironment, thereby improving the tumor hypoxia state and enhancing the efficacy of photodynamic therapy (PDT) by Ce6. Both the in vitro and in vivo experiments showed that the MNMCF-guided CDT/PDT combination therapy could effectively ablate tumors without the drawbacks of poor tolerability and potential long-term side effects. Therefore, the prepared MNMCF NPs can be used as promising candidates for synergistic CDT/PDT tumor therapy.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Biophotonics in Dentistry

The aim of this review paper is to concentrate on the use and application of photonics in dentistry. More than one hundred review and research articles were comprehensively analysed in terms of applications of photonics in dentistry, including surgical applications, as well as dental biomaterials, diagnosis and treatments. In biomedical engineering, various fields, such as biology, chemistry, material and physics, come together in to tackle a disease/disorder either as a diagnostic tool or an option for treatment. Engineers believe that biophotonics is the application of photonics in medicine, whereas photonics is simply a technology for creating and connecting packets of light energy, known as photons. This review paper provides a comprehensive discussion of its main elements, such as photoelasticity, interferometry techniques, optical coherence tomography, different types of lasers, carbon nanotubes, graphene and quantum dots.

The improvement of biocompatibility by incorporating porphyrins into carbon dots with photodynamic effects and pH sensitivities

Photodynamic therapy (PDT) is a promising new treatment for cancer; however, the hydrophobic interactions and poor solubility in water of photosensitizers limit the use in clinic. Nanoparticles especially carbon dots have attracted the attention of the world^'s scientists because of their unique properties such as good solubility and biocompatibility. In this paper, we integrated carbon dots with different porphyrins to improve the properties of porphyrins and evaluated their efficacy as PDT drugs. The spectroscopic characteristics of porphyrins nano-conjugates were studied. Singlet oxygen generation rate and the light- and dark-induced toxicity of the conjugates were studied. Our results showed that the covalent interaction between CDs and porphyrins has improved the biocompatibility. The synthesized conjugates also inherit the pH sensitivity of the carbon dots, while the conjugation also decreases the hemolysis ratio making them a promising candidate for PDT. The incorporation of carbon dots into porphyrins improved their biocompatibility by reducing toxicity.

Photodynamic therapy for squamous cell carcinoma of the head and neck: narrative review focusing on photosensitizers

This narrative review aimed to evaluate the effectiveness of PDT in early or advanced squamous cell carcinoma of the head and neck (SCCHN). Scopus, MEDLINE/PubMed, and Embase were searched electronically following the PRISMA protocol. Quality assessment was performed according to JBI, NIH, and AMSTAR protocols. The main outcomes evaluated were treatment response, recurrence, survival, and adverse effects. A total of 49 articles met the search criteria: 43 case series, two cohort studies, two prospective before-after clinical trials, one systematic review, and one meta-analysis. Data from 2121 SCCHN patients were included. The response to PDT was variable according to the type of photosensitizer, tumor location, and tumor stage. In general, higher complete responses rated were observed in T1/T2 SCCHN, mainly with mTHPC-mediated PDT. With regard to T3/T4 or advanced SCCHN tumors, there is no compelling evidence suggesting the effectiveness of PDT. Any adverse effects reported were well tolerated by patients. The present review suggests that PDT is a promising treatment modality for early-stage SCCHN. Although there are limitations due to the low level of evidence of the included studies, we believe that the present review could help to design robust clinical trials to determine the efficacy of PDT in SCCHN.

Long-term outcomes of aminolevulinic acid photodynamic therapy for treatment of recalcitrant laryngeal premalignant lesions

OBJECTIVE

To assess long-term outcomes of ALA-PDT in treating recalcitrant laryngeal leukoplakia.

STUDY DESIGN

Retrospective Case-Control.

METHODS

We reviewed all laryngeal leukoplakia patients treated with ALA-PDT compared with angiolytic laser treatment alone (585 nm PDL or 532 nm KTP laser) from 2000 to 2019. Patients with laryngeal cancer (or a history of laryngeal cancer), leukoplakia previously treated with radiation and no pathologic report were excluded. Patient demographics, procedure details and outcomes were examined including histopathologic diagnosis, procedures performed, ALA usage, recurrence of leukoplakia and the development of cancer.

RESULTS

We identified 132 patients with laryngeal leukoplakia: 42 were treated with ALA-PDT and 90 were treated with an angiolytic laser alone (Laser group). The proportion of cases of high-grade dysplasia was 57.1% in the ALA-PDT group compared to 32.2% in the Laser group. In high-grade dysplasia cases, there was a statistically significant better recurrence-free survival (RFS) at 12 months and 60 months in those who underwent ALA-PDT 71.4% and 7.1% vs Laser 25% and 0% (p = .01). However, for overall groups, there was no difference in RFS (p = .25). Voice outcomes (patient subjective report) improved or were stable in 75% of subjects with no serious side effects reported.

CONCLUSION

ALA-PDT for recalcitrant and high-grade dysplasia is highly effective with improved recurrence-free survival compared to laser alone. ALA-PDT may be an appropriate therapy in patients who have failed prior angiolytic laser alone.

Chitosan-tripolyphosphate nanoparticles-mediated co-delivery of MTHFD1L shRNA and 5-aminolevulinic acid for combination photodynamic-gene therapy in oral cancer

BACKGROUND

Rationally designed nanostructured materials can produce improved drug carriers that play an increasingly important role in cancer treatment. In comparison with conventional drug combination approaches, using co-delivery systems of multiple drugs achieves sophisticated targeting strategies and multifunctionality.

METHODS

First, a nano-co-delivery of chitosan/tripolyphosphate (CS-TPP) was synthesized and characterized combining 5-aminolevulinic acid photodynamic therapy (ALA-PDT) with methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) shRNA. In this report, we investigated the efficacy of the simultaneous delivery of shRNA/photosensitizer on the gene expression of oral squamous cell carcinoma (OSCC) cells. The efficacy of CS-TPP-(shMTHFD1L-ALA)-PDT in inducing apoptosis and in generating of reactive oxygen species (ROS) in vitro was then assessed by Annexin V-PI and DCFH-DA assays respectively. In vivo therapeutic experiments were conducted in well-established orthotopic animal models of HNSCC.

RESULTS

The results showed that the CS-TPP-(shMTHFD1L-ALA) nanoparticles (NPs) were approximately 145 nm in size. The cytotoxicity of OSCC cells was significantly increased by co-delivery of MTHFD1L shRNA and ALA-PDT compared with other groups. Furthermore, individual and combined therapies revealed remarkable pro-apoptotic, ROS and anti-tumorigenesis effects, and CS-TPP-(shMTHFD1L-ALA)-PDT had additive effects in vitro and in vivo.

CONCLUSION

These observations indicate that CS-TPP-(shMTHFD1L-ALA) NPs may be an ideal candidate for gene/photosensitizer delivery.

Synthesis and Characterization of Polyvinylpyrrolidone-Modified ZnO Quantum Dots and Their In Vitro Photodynamic Tumor Suppressive Action

Despite the numerous available treatments for cancer, many patients succumb to side effects and reoccurrence. Zinc oxide (ZnO) quantum dots (QDs) are inexpensive inorganic nanomaterials with potential applications in photodynamic therapy. To verify the photoluminescence of ZnO QDs and determine their inhibitory effect on tumors, we synthesized and characterized ZnO QDs modified with polyvinylpyrrolidone. The photoluminescent properties and reactive oxygen species levels of these ZnO/PVP QDs were also measured. Finally, in vitro and in vivo experiments were performed to test their photodynamic therapeutic effects in SW480 cancer cells and female nude mice. Our results indicate that the ZnO QDs had good photoluminescence and exerted an obvious inhibitory effect on SW480 tumor cells. These findings illustrate the potential applications of ZnO QDs in the fields of photoluminescence and photodynamic therapy.

Rose Bengal and Future Directions in Larynx Tumor Photodynamic Therapy†

Photodynamic Therapy (PDT) seems to be a promising method in the treatment of larynx tumor tissues. The aim of the present analysis was the study of photosensitizer penetration of larynx tissue associated with the application of PDT in vitro. This study is based on the use of photosensitive compounds Rose Bengal (RB) that selectively accumulate in larynx tissue. The selection of the study group of patients who will undergo surgery in accordance with medical principles was of key importance for the project. Histopathological examination of samples subjected to PDT revealed numerous changes in the morphology of the cancer cells and surrounding tissues. After PDT treatment, the number of tumor cells decreased compared with the cells number before PDT and the arrangement was relatively loose. After PDT with RB the nuclei morphology was incomplete and fragmented. The effects of the applied PDT of larynx in vitro were assessed under an optical microscope. The future directions in larynx tumor PDT with the use of upconversion nanoparticles (UPCNP) is also discussed.

Potential of Cyanine Derived Dyes in Photodynamic Therapy

Photodynamic therapy (PDT) is a method of cancer treatment that leads to the disintegration of cancer cells and has developed significantly in recent years. The clinically used photosensitizers are primarily porphyrin, which absorbs light in the red spectrum and their absorbance maxima are relatively short. This review presents group of compounds and their derivatives that are considered to be potential photosensitizers in PDT. Cyanine dyes are compounds that typically absorb light in the visible to near-infrared-I (NIR-I) spectrum range (750-900 nm). This meta-analysis comprises the current studies on cyanine dye derivatives, such as indocyanine green (so far used solely as a diagnostic agent), heptamethine and pentamethine dyes, squaraine dyes, merocyanines and phthalocyanines. The wide array of the cyanine derivatives arises from their structural modifications (e.g., halogenation, incorporation of metal atoms or organic structures, or synthesis of lactosomes, emulsions or conjugation). All the following modifications aim to increase solubility in aqueous media, enhance phototoxicity, and decrease photobleaching. In addition, the changes introduce new features like pH-sensitivity. The cyanine dyes involved in photodynamic reactions could be incorporated into sets of PDT agents.

Application of photodynamic therapy in immune-related diseases

Photodynamic therapy (PDT) is a therapeutic modality that utilizes photodamage caused by photosensitizers and oxygen after exposure to a specific wavelength of light. Owing to its low toxicity, high selectivity, and minimally invasive properties, PDT has been widely applied to treat various malignant tumors, premalignant lesions, and infectious diseases. Moreover, there is growing evidence of its immunomodulatory effects and potential for the treatment of immune-related diseases. This review mainly focuses on the effect of PDT on immunity and its application in immune-related diseases.

Alternative methods of photodynamic therapy and oxygen consumption measurements-A review

Photooxidation generates reactive oxygen species (ROS) through the interaction of dyes or surfaces with light radiation of appropriate wavelength. The reaction is of wide utility and is highly effective in photodynamic therapy (PDT) of various types of cancer and skin disease. Understanding generation of singlet oxygen has contributed to the development of PDT and its subsequent use in vivo. However, this therapy has some limitations that prevent its use in the treatment of cancers located deep within the body. The limited depth of light penetration through biological tissue limits initiation of PDT action in deep tissue. Measurement of oxygen photo consumption is critical due to tumor hypoxia, and use of magnetic resonance imaging (MRI) is particularly attractive since it is non-invasive. This article presents bioluminescence (BL) and chemiluminescence (CL) phenomena based on publications from the last 20 years, and preliminary results from our lab in the use of MRI to measure oxygen concentration in water. Current work is aimed at improving the effectiveness of singlet oxygen delivery to deep tissue cancer.

Clinical Trials and Basic Research in Photodynamic Diagnostics and Therapies from the Center for Laser Diagnostics and Therapy in Poland

The purpose of this review is to present an overview of the development of photodiagnostic and photodynamic therapy (PDD and PDT) techniques in Poland. The paper discusses the principles of PDD, including fluorescent techniques in determining precancerous conditions and cancers of the skin, digestive tract, bladder and respiratory tract. Methods of PDT of cancer will be discussed and the current state of knowledge as well as future trends in the development of photodynamic techniques will be presented, including the possibility of using photodynamic antimicrobial therapy. Research pioneers in photodynamic medicine such as Thomas Dougherty are an inspiration for the development of methods of PDD and PDT in our Clinic. The Center for Laser Diagnostics and Therapy in Bytom, Poland, promotes the propagation of PDD and PDT through the training of clinicians and raising awareness among students in training and the general public. Physicians at the Center are engaged in photomedical research aimed at clinical implementation and exploration of new avenues in photomedicine while optimizing existing modalities. The Center promotes dissemination of clinical results from a wide range of topics in PDD and PDT and serving as representative authorities of photodynamic medicine in Poland and Europe.

Effective Combined Photodynamic Therapy with Lipid Platinum Chloride Nanoparticles Therapies of Oral Squamous Carcinoma Tumor Inhibition

Encapsulating cisplatin (CDDP) into liposomes to form lipid-platinum-chloride nanoparticles (LPC NPs) has shown a promising anticancer effect in melanoma, bladder, and liver cancer models. This promising anticancer effect of LPC NPs challenges us to study its implications in combination with photodynamic therapy (PDT). Herein, we report the therapeutic efficacy of PDT+LPC on a xenograft model of oral squamous cell carcinoma (OSCC). Results showed that PDT+LPC significantly reduced the tumor volume by up to ~112%. Meanwhile, LPC, PDT+CDDP, or the CDDP group showed ~98.8%, ~73.1%, or ~39.5% volume reductions, respectively. Histological examination suggests that PDT+LPC or LPC treatment showed minimal side effects on renal damage compared to either CDDP or the PDT+CDDP group. Immunohistochemistry staining (IHC) staining on Ki-67, CD31, cleaved caspase-3, TUNEL assays, and western blots of tumor suppressor p53 confirmed consistent results. Most importantly, PDT+LPC prolonged tumor growth inhibition, which leads to minimum chemotherapy treatment administrations. Results suggest that PDT cytotoxicity provided a potent additive effect towards chemotherapy efficacy. Therefore, combined PDT with LPC NPs enhanced the therapeutic outcome in human OSCC.

Stroma-Rich Co-Culture Multicellular Tumor Spheroids as a Tool for Photoactive Drugs Screening

Conventional 3D multicellular tumor spheroids of head and neck squamous cell carcinoma (HNSCC) consisting exclusively of cancer cells have some limitations. They are compact cell aggregates that do not interact with their extracellular milieu, thus suffering from both insufficient extracellular matrix (ECM) deposition and absence of different types of stromal cells. In order to better mimic in vivo HNSCC tumor microenvironment, we have constructed a 3D stroma-rich in vitro model of HNSCC, using cancer-associated MeWo skin fibroblasts and FaDu pharynx squamous cell carcinoma. The expression of stromal components in heterospheroids was confirmed by immunochemical staining. The generated co-culture FaDu/MeWo spheroids were applied to study penetration, distribution and antitumor efficacy of photoactive drugs such as Temoporfin and Chlorin e6 used in the photodynamic therapy flow cytometry and fluorescence microscopy techniques. We also investigated the distribution of photodiagnostic agent Indocyanine Green. We demonstrated that the presence of stroma influences the behavior of photoactive drugs in different ways: (i) No effect on Indocyanine Green distribution; (ii) lower accumulation of Chlorin e6; (iii) better penetration and PDT efficiency of Temoporfin. Overall, the developed stroma-rich spheroids enlarge the arsenal of in vitro pre-clinical models for high-throughput screening of anti-cancer drugs.

Mechanistic Investigation into DNA Modification by a RuII ,RhIII Bimetallic Complex

Despite significant progress in the treatment of cancer, there remains an urgent need for more effective therapies that also have less impact on patient wellbeing. Photodynamic therapy employs targeted light activation of a photosensitizer in selected tissues, thereby reducing off-target toxicity. Our group previously reported a Ru^II ,Rh^III bimetallic architecture that displays multifunctional covalent photomodification of DNA in the therapeutic window in an oxygen-independent manner, features that are essential for treating deep and hypoxic tumors. Herein, we explore the mechanism by which a new analogue, [(phen)₂ Ru(dpp)Rh(phen)Cl₂ ]³⁺ , or Ru^II -Rh^III , interacts with DNA. We established that Ru^II -Rh^III exhibits "light switch" behavior in the presence of DNA, undergoing strong electrostatic interactions that might involve groove binding. Furthermore, these noncovalent interactions play a major role in the covalent photobinding and photocleavage of DNA, which occur according to an oxygen-independent mechanism. Polymerase chain reaction (PCR) revealed that covalent modification of DNA by Ru^II -Rh^III , especially photobinding, is critical to inhibiting amplification, thus suggesting that the complex could exert its toxic activity by interfering with DNA replication in cells. This new structural motif, with phenanthroline at all three terminal ligand positions, has a number of properties that are promising for the continued refinement of photodynamic-therapy strategies.

A theoretical study of a series of water-soluble triphenylamine photosensitizers for two-photon photodynamic therapy

In this study, the therapeutic activity of a series of water-soluble triphenylamine (TP) photosensitizers (Ps) was explored by using theoretical simulations. The key photophysical parameters which determined the efficiency of Ps, such as absorption electronic spectra, singlet-triplet energy gaps and spin-orbit matrix elements were calculated at density functional theory and its time-dependent extension (DFT, TD-DFT). The calculated results showed that these TP photosensitizers possessed large two-photon absorption cross-section in the near-infrared region (NIR), efficient intersystem crossing (ISC) transition from the first singlet excited state to the low lying triplet excited states and sufficient energy for generating reactive oxygen species (ROS). These suitable features made these TP series holding great promise for applications in two-photon photodynamic therapy (PDT). These TP photosensitizers studied here in principle extended the application range of two-photon PDT in water solution.

Anti-angiogenic treatment (Bevacizumab) improves the responsiveness of photodynamic therapy in colorectal cancer

Photodynamic therapy (PDT) is a treatment utilizing the combined action of photosensitizers and light for the treatment of various cancers. The mechanisms for tumor destruction after PDT include direct tumor cell kill by singlet oxygen species (OS), indirect cell kill via vascular damage, and an elicited immune response. However, it has been reported that many cellular activators, including vascular endothelial growth factor (VEGF), are produced by tumor cells after PDT. In this study, we demonstrate that meta-tetra(hydroxyphenyl) chlorin (mTHPC)-based photodynamic therapy combined with bevacizumab (Avastin™), an anti-VEGF neutralizing monoclonal antibody that blocks the binding of VEGF to its receptor, can enhance the effectiveness of each treatment modality. We evaluated the efficacy of bevacizumab-based anti-angiogenesis in combination with PDT as well as the resulting VEGF levels and microvessel density (MVD) in a mouse model of human colon cancer. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were performed to assess VEGF concentrations and microvessel density in the various treatment groups, and confocal imaging and high performance liquid chromatography (HPLC) analyses were used to measure the distribution and concentration of mTHPC in tumors. Our results demonstrate that combination of PDT followed by bevacizumab significantly elicits a greater tumor response whereas bevacizumab treatment prior to PDT led to a reduced tumor response. Immunostaining and ELISA analyses revealed a lower expression of VEGF in tumors treated with combination therapy of PDT followed by bevacizumab. However, bevacizumab treatment decreased the accumulation of mTHPC in tumors 24 h after administration, which complemented the results of decreased anti-tumor efficacy of bevacizumab followed by PDT.

Safety evaluation of repeated intravenous infusion of sinoporphyrin with and without PDT in rats

Photodynamic therapy (PDT) is a promising antineoplastic modality in the oncology field. We assessed the safety of repeated intravenous administrations of sinoporphyrin, a porphyrin derivative, with and without illumination in rats. Toxicokinetic studies of single and multiple administrations of sinoporphyrin were also carried out. Sprague-Dawley rats were randomly assigned to the dark-toxicity and PDT groups. Animals in the dark toxicity group received an i.v. infusion of sinoporphyrin at 3 doses: 2 mg kg^-1, 6 mg kg^-1, and 18 mg kg^-1. The PDT group included 2 doses of sinoporphyrin (2 mg kg^-1 and 18 mg kg^-1), and the rats received 60 J of 630 nm laser illumination 24 h after photosensitizer infusion. The treatments were repeated every 7 days for 5 cycles and were followed by a 14-day recovery period. Systematic analyses were conducted at the end of treatment and recovery periods. Blood samples were obtained 5 min, 30 min, 2 h, 8 h, 24 h, 48 h, 72 h, and 96 h after the first and fifth treatments for toxicokinetic studies. Sinoporphyrin-PDT led to the death of one out of 270 rats; the dead animal had been treated with 18 mg kg^-1 sinoporphyrin and died at the end of the fifth PDT treatment. Liver injury, the primary toxicity observed in the study, was identified using biochemical tests, necropsy, and histopathology. Elevated white blood cell and neutrophil counts were found in the rats in both the dark toxicity and PDT groups. Skin lesions at the illumination site were obvious in the PDT group. Pigment deposits were detected in multiple organs such as the liver, spleen, lymph nodes, and ovaries in the 6 mg kg^-1 and 18 mg kg^-1 groups. No other abnormalities were observed. The toxicokinetic parameters of single and multiple sinoporphyrin administrations were calculated and compared. Repeated sinoporphyrin administrations both alone and in combination with laser illumination were tolerable, and all toxicities were transient. The no observed adverse effect level (NOAEL) for repeated sinoporphyrin administration and sinoporphyrin-PDT was 6 mg kg^-1 and 2 mg kg^-1, respectively. Further studies are warranted.

A Review of Photodynamic Therapy for Neoplasms of the Head and Neck

Photodynamic therapy (PDT) involves the use of a phototoxic drug which is activated by low powered laser light to destroy neoplastic cells. Multiple photosensitizers have been studied and tumors have been treated in a variety of head and neck sites over the last 30 years. PDT can effectively treat head and neck tumors, particularly those of the superficial spreading type, and the classic application of this technology has been in the patient with a wide field of dysplastic change and superficial carcinomatosis. Interstitial treatment has been used to treat more invasive cancer. Data is available from case series and institutional experiences, but very little randomized data is available. We review the mechanisms of action, historical development, available data, and current knowledge regarding PDT for the various head and neck subsites, and discuss possible future directions, with an emphasis on clinical application.

Treatment of Epithelioid angiosarcoma with Topical ALA-PDT in the course of surgery

BACKGROUND

Epithelioid angiosarcoma is a high grade malignancy sarcoma of soft tissue, which is hard to diagnose and completely excise without causing functional and cosmetic problems. Moreover, the high rate of recurrence is hard to salvage. Photodynamic therapy is a novel treatment protocol which can selectively destroy tumor cell with good functional and cosmetic outcomes.

METHODS

This is a case about a 81 years old patient with Epithelioid angiosarcoma in the right medial angle of eye, which received surgery and ALA photodynamic therapy.

RESULTS

There is no recurrence in one year after treatment of surgery and photodynamic therapy in the course of surgery.

CONCLUSIONS

Excision combined with photodynamic therapy during operation is a promising strategy towards tumors which are hard to resect thoroughly and have a high risk of recurrence.

Photodynamic treatment outcomes of potentially-malignant lesions and malignancies of the head and neck region: A systematic review

AIM

The aim of the present study was to systematically review the efficacy of photodynamic therapy (PDT) in the management of oral potentially-malignant disorders (PMDS) and head and neck squamous cell carcinoma (HNSCC).

METHODS

From 1985 to 2015, PubMed/Medline, Google Scholar, EMBASE, and ISI Web of Knowledge were searched using different combinations of the following key words: PDT, oral precancer, leukoplakia, erythroplakia, erythroleukoplakia, verrucous hyperplasia, oral submucous fibrosis, and HNSCC. Review articles, experimental studies, case reports, commentaries, letters to the editor, unpublished articles, and articles published in languages other than English were excluded.

RESULTS

Twenty-six studies were included in the present study. The number of patients ranged from 2 to 147, with a mean age of 50-67 years. The reported numbers of PMDS and HNSCC ranged between 5 and 225. Photosensitizers used were aminolevulinic acid, meta-tetrahydroxyphenylchlorin, Foscan, hematoporphyrin derivatives, Photofrin, Photosan, and chlorine-e6. Laser wavelength, power density, irradiation duration were 585-652 nm, 50-500 mW/cm² , and 1-143 minutes, respectively. Complete, partial, and no response to PDT was found in 22.58%-100%, 4%-66%, and 0%-38.70% of PMDS, respectively, and 16%-100% of complete response in HNSCC patients.

CONCLUSION

PDT is effective in the management of PMDS and HNSCC.

Chemophototherapy: An Emerging Treatment Option for Solid Tumors

Near infrared (NIR) light penetrates human tissues with limited depth, thereby providing a method to safely deliver non-ionizing radiation to well-defined target tissue volumes. Light-based therapies including photodynamic therapy (PDT) and laser-induced thermal therapy have been validated clinically for curative and palliative treatment of solid tumors. However, these monotherapies can suffer from incomplete tumor killing and have not displaced existing ablative modalities. The combination of phototherapy and chemotherapy (chemophototherapy, CPT), when carefully planned, has been shown to be an effective tumor treatment option preclinically and clinically. Chemotherapy can enhance the efficacy of PDT by targeting surviving cancer cells or by inhibiting regrowth of damaged tumor blood vessels. Alternatively, PDT-mediated vascular permeabilization has been shown to enhance the deposition of nanoparticulate drugs into tumors for enhanced accumulation and efficacy. Integrated nanoparticles have been reported that combine photosensitizers and drugs into a single agent. More recently, light-activated nanoparticles have been developed that release their payload in response to light irradiation to achieve improved drug bioavailability with superior efficacy. CPT can potently eradicate tumors with precise spatial control, and further clinical testing is warranted.

Photodynamic Therapy in Dentistry

Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemo-therapy, involves the use of a photoactive dye (photosensitizer) that is activated by exposure to light of a specific wavelength in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals. These very reactive chemical species can damage proteins, lipids, nucleic acids, and other cellular components. Applications of PDT in dentistry are growing rapidly: the treatment of oral cancer, bacterial and fungal infection therapies, and the photodynamic diagnosis (PDD) of the malignant transformation of oral lesions. PDT has shown potential in the treatment of oral leukoplakia, oral lichen planus, and head and neck cancer. Photodynamic antimicrobial chemotherapy (PACT) has been efficacious in the treatment of bacterial, fungal, parasitic, and viral infections. The absence of genotoxic and mutagenic effects of PDT is an important factor for long-term safety during treatment. PDT also represents a novel therapeutic approach in the management of oral biofilms. Disruption of plaque structure has important consequences for homeostasis within the biofilm. Studies are now leading toward selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. Dentists deal with oral infections on a regular basis. The oral cavity is especially suitable for PACT, because it is relatively accessible to illumination.

Phototoxicity of Liposomal Zn- and Al-phthalocyanine Against Cervical and Oral Squamous Cell Carcinoma Cells In Vitro

Background

Photodynamic therapy (PDT) utilizes light to activate a photosensitizer in the presence of oxygen, and leads to local photodamage by the generation of highly reactive oxygen species (ROS). Liposomal delivery of photosensitizers is adaptable to the treatment of cancers. We examined the phototoxicity of free or liposome-embedded phthalocyanine photosensitizers using HeLa cervical carcinoma and HSC-3 oral squamous cell carcinoma cells.

Material/Methods

Liposomes were composed of palmitoyloleoyphosphatidylcholine (POPC): phosphatidylglycerol (PG), and contained either zinc phthalocyanine (ZnPc) or aluminum phthalocyanine chloride (AlPc). Free or liposomal ZnPc and AlPc were incubated with cells for 24 h at 37°C. Cells incubated with ZnPc were exposed to broadband visible light (350–800 nm; light dose 43.2 J/cm²), whereas cells treated with AlPc were exposed to light at 690 nm (light dose 3.6 J/cm²). The effect of folate receptor-targeted liposomal ZnPc was evaluated with HeLa cells. Cytotoxicity was analyzed by the Alamar Blue assay.

Results

Cell viability, expressed as a percentage of control cells, was calculated according to the formula [(A570–A600) of test cells]×100/[(A570–A600) of control cells]. The relative percentage changes then defined the phototoxic efficacy of the experimental conditions. In HeLa cells, 1 μM free ZnPc and AlPc, reduced cell viability to 52.7±2.1 and 15.4±8.0%, respectively. Liposomal phthalocyanines, at 0.1, 0.5, and 1.0 μM, reduced the viability to 68.0±8.6, 15.1±9.9 and 0% (ZnPc), and to 25.8±8.2, 0 and 0% (AlPc), respectively. In HSC-3 cells, 1 μM free ZnPc and AlPc, reduced cell viability to 22.1±2.8 and 56.6±8.6%, respectively. With 1 μM liposomal ZnPc and AlPc, the viability was reduced to 0 and 21.3±0.3%, respectively.

Conclusions

The embedding of phthalocyanines in liposomes enhanced their phototoxicity and this effect was dependent on cell type.

Lipid nanoemulsions and liposomes improve photodynamic treatment efficacy and tolerance in CAL-33 tumor bearing nude mice

Background

Photodynamic therapy (PDT) as promising alternative to conventional cancer treatments works by irradiation of a photosensitizer (PS) with light, which creates reactive oxygen species and singlet oxygen (¹O₂), that damage the tumor. However, a routine use is hindered by the PS’s poor water solubility and extended cutaneous photosensitivity of patients after treatment. In our study we sought to overcome these limitations by encapsulation of the PS m-tetrahydroxyphenylchlorin (mTHPC) into a biocompatible nanoemulsion (Lipidots).

Results

In CAL-33 tumor bearing nude mice we compared the Lipidots to the existing liposomal mTHPC nanoformulation Foslip and the approved mTHPC formulation Foscan. We established biodistribution profiles via fluorescence measurements in vivo and high performance liquid chromatography (HPLC) analysis. All formulations accumulated in the tumors and we could determine the optimum treatment time point for each substance (8 h for mTHPC, 24 h for Foslip and 72 h for the Lipidots). We used two different light doses (10  and 20 J/cm²) and evaluated immediate PDT effects 48 h after treatment and long term effects 14 days later. We also analyzed tumors by histological analysis and performing reverse transcription real-time PCR with RNA extracts. Concerning tumor destruction Foslip was superior to Lipidots and Foscan while with regard to tolerance and side effects Lipidots were giving the best results.

Conclusions

We could demonstrate in our study that nanoformulations are superior to the free PS mTHPC. The development of a potent nanoformulation is of major importance because the free PS is related to several issues such as poor bioavailability, solubility and increased photosensibility of patients. We could show in this study that Foslip is very potent in destroying the tumors itself. However, because the Lipidots' biocompatibility is outstanding and superior to the liposomes we plan to carry out further investigations and protocol optimization. Both nanoformulations show great potential to revolutionize PDT in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0223-8) contains supplementary material, which is available to authorized users.

PLGA nanoparticle encapsulation reduces toxicity while retaining the therapeutic efficacy of EtNBS-PDT in vitro

Photodynamic therapy regimens, which use light-activated molecules known as photosensitizers, are highly selective against many malignancies and can bypass certain challenging therapeutic resistance mechanisms. Photosensitizers such as the small cationic molecule EtNBS (5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride) have proven potent against cancer cells that reside within acidic and hypoxic tumour microenvironments. At higher doses, however, these photosensitizers induce "dark toxicity" through light-independent mechanisms. In this study, we evaluated the use of nanoparticle encapsulation to overcome this limitation. Interestingly, encapsulation of the compound within poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-EtNBS) was found to significantly reduce EtNBS dark toxicity while completely retaining the molecule's cytotoxicity in both normoxic and hypoxic conditions. This dual effect can be attributed to the mechanism of release: EtNBS remains encapsulated until external light irradiation, which stimulates an oxygen-independent, radical-mediated process that degrades the PLGA nanoparticles and releases the molecule. As these PLGA-encapsulated EtNBS nanoparticles are capable of penetrating deeply into the hypoxic and acidic cores of 3D spheroid cultures, they may enable the safe and efficacious treatment of otherwise unresponsive tumour regions.

Photodynamic therapy of tumors with pyropheophorbide-a-loaded polyethylene glycol-poly(lactic-co-glycolic acid) nanoparticles

Photodynamic therapy (PDT) has many advantages in treating cancers, but the lack of ideal photosensitizers continues to be a major limitation restricting the clinical utility of PDT. This study aimed to overcome this obstacle by generating pyropheophorbide-a-loaded polyethylene glycol–poly(lactic-co-glycolic acid) nanoparticles (NPs) for efficient tumor-targeted PDT. The fabricated NPs were efficiently internalized in the mitochondrion by cancer cells, and they efficiently killed cancer cells in a dose-dependent manner when activated with light. Systemically delivered NPs were highly enriched in tumor sites, and completely ablated the tumors in a xenograft KB tumor mouse model when illuminated with 680 nm light (156 mW/cm², 10 minutes). The results suggested that this tumor-specific NP-delivery system for pyropheophorbide-a has the potential to be used in tumor-targeted PDT.

Toxicities and early outcomes in a phase 1 trial of photodynamic therapy for premalignant and early stage head and neck tumors

OBJECTIVES

Management of early superficial lesions in the head and neck remains complex. We performed a phase 1 trial for high-grade premalignant and early superficial lesions of the head and neck using photodynamic therapy (PDT) with Levulan (ALA).

MATERIALS AND METHODS

Thirty-five subjects with high grade dysplasia, carcinoma in situ, or microinvasive (⩽1.5mm depth) squamous cell carcinoma were enrolled. Cohorts of 3-6 patients were given escalating intraoperative light doses of 50-200J/cm(2) 4-6h after oral administration of 60mg/kg ALA. Light at 629-635nm was delivered in a continuous (unfractionated) or fractionated (two-part) schema.

RESULTS

PDT was delivered to 30/35 subjects, with 29 evaluable. There was one death possibly due to the treatment. The regimen was otherwise tolerable, with a 52% rate of grade 3 mucositis which healed within several weeks. Other toxicities were generally grade 1 or 2, including odynophagia (one grade 4), voice alteration (one grade 3), and photosensitivity reactions. One patient developed grade 5 sepsis. With a median follow-up of 42months, 10 patients (34%) developed local recurrence; 4 of these received 50J/cm(2) and two each received 100, 150, and 200J/cm(2). Ten (34%) patients developed recurrence adjacent to the treated field. There was a 69% complete response rate at 3months.

CONCLUSIONS

ALA-PDT is well tolerated. Maximum Tolerated Dose appears to be higher than the highest dose used in this study. Longer followup is required to analyze effect of light dose on local recurrence. High marginal recurrence rates suggest use of larger treatment fields.

Photosensitizers binding to nucleic acids as anticancer agents

Cationic porphyrins (Prs) and phthalocyanines (Pcs) are strong photosensitizers that have drawn much attention for their potential in photodynamic therapy. These compounds have the interesting property of binding to nucleic acids, in particular G-rich quadruplex-forming sequences in DNA and RNA. In this review, we highlight their potential as anticancer drugs.

Ruthenium porphyrin-induced photodamage in bladder cancer cells

Photodynamic therapy (PDT) is a noninvasive treatment for solid malignant and flat tumors. Light activated sensitizers catalyze photochemical reactions that produce reactive oxygen species which can cause cancer cell death. In this work we investigated the photophysical properties of the photosensitizer ruthenium(II) porphyrin (RuP), along with its PDT efficiency onto rat bladder cancer cells (AY27). Optical spectroscopy verified that RuP is capable to activate singlet oxygen via blue and red absorption bands and inter system crossing (ISC) to the triplet state. In vitro experiments on AY27 indicated increased photo-toxicity of RuP (20μM, 18h incubation) after cell illumination (at 435nm), as a function of blue light exposure. Cell survival fraction was significantly reduced to 14% after illumination of 20μM RuP with 15.6J/cm(2), whereas the "dark toxicity" of 20μM RuP was 17%. Structural and morphological changes of cells were observed, due to RuP accumulation, as well as light-dependent cell death was recorded by confocal microscopy. Flow cytometry verified that PDT-RuP (50μM) triggered significant photo-induced cellular destruction with a photoxicity of (93%±0.9%). Interestingly, the present investigation of RuP-PDT showed that the dominating mode of cell death is necrosis. RuP "dark toxicity" compared to the conventional chemotherapeutic drug cisplatin was higher, both evaluated by the MTT assay (24h). In conclusion, the present investigation shows that RuP with or without photoactivation induces cell death of bladder cancer cells.

A Surgical View of Photodynamic Therapy in Oncology: A Review

Clinical photodynamic therapy (PDT) has existed for over 30 years, and its scientific basis has been known and investigated for well over 100 years. The scientific foundation of PDT is solid and its application to cancer treatment for many common neoplastic lesions has been the subject of a huge number of clinical trials and observational studies. Yet its acceptance by many clinicians has suffered from its absence from the undergraduate and/or postgraduate education curricula of surgeons, physicians, and oncologists. Surgeons in a variety of specialties many with years of experience who are familiar with PDT bear witness in many thousands of publications to its safety and efficacy as well as to the unique role that it can play in the treatment of cancer with its targeting precision, its lack of collateral damage to healthy structures surrounding the treated lesions, and its usage within minimal access therapy. PDT is closely related to the fluorescence phenomenon used in photodiagnosis. This review aspires both to inform and to present the clinical aspect of PDT as seen by a surgeon.

Photodynamic therapy with 3-(1'-hexyloxyethyl) pyropheophorbide-a for early-stage cancer of the larynx: Phase Ib study

Background

The purpose of this study was for us to report results regarding the safety of 3‐(1′‐hexyloxyethyl) pyropheophorbide‐a (HPPH) mediated photodynamic therapy (PDT) in early laryngeal disease, and offer preliminary information on treatment responses.

Methods

A single‐institution, phase Ib, open label, noncomparative study of HPPH‐PDT in patients with high‐risk dysplasia, carcinoma in situ, and T1 squamous cell carcinoma (SCC) of the larynx. The primary outcomes were safety and maximum tolerated dose (MTD), and the secondary outcome was response.

Results

Twenty‐nine patients and 30 lesions were treated. The most common adverse event (AE) was transient hoarseness of voice. Severe edema, requiring tracheostomy, was the most serious AE, which occurred in 2 patients within several hours of therapy. The MTD was 100 J/cm². Patients with T1 SCC seemed to have good complete response rate (82%) to HPPH‐PDT at MTD.

Conclusion

HPPH‐PDT can be safely used to treat early‐stage laryngeal cancer, with potential efficacy. © 2015 The Authors Head & Neck Published by Wiley Periodicals, Inc. Head Neck38: E377–E383, 2016

Controlled light field concentration through turbid biological membrane for phototherapy

Laser propagation through a turbid rat dura mater membrane is shown to be controllable with a wavefront modulation technique. The scattered light field can be refocused into a target area behind the rat dura mater membrane with a 110 times intensity enhancement using a spatial light modulator. The efficient laser intensity concentration system is demonstrated to imitate the phototherapy for human brain tumors. The power density in the target area is enhanced more than 200 times compared with the input power density on the dura mater membrane, thus allowing continued irradiation concentration to the deep lesion without damage to the dura mater. Multibeam inputs along different directions, or at different positions, can be guided to focus to the same spot behind the membrane, hence providing a similar gamma knife function in optical spectral range. Moreover, both the polarization and the phase of the input field can be recovered in the target area, allowing coherent field superposition in comparison with the linear intensity superposition for the gamma knife.