Effect of photosensitizers photosens, photodithazine and hypericin on glioma cells and primary neuronal cultures : a comparative analysis

The aim of the study was to compare the effect of photosensitizers photosens, photodithazine, and hypericin on primary brain cell cultures, and assess their toxic effect on tumor and normal nervous cells in order to choose the optimal photodynamic agent for glioma therapy. Materials and Methods. The cytotoxicity of photosens (NIOPIK, Russia), photodithazine (Veta-grand, Russia) and hypericin (Merck KGaA; Sigma-Aldrich, Germany) was assessed on primary brain cell cultures obtained from C57BL/6 mice (gestation day 18). On day 14 of cultivation, the tested photosensitizers were added to a culture medium at concentrations of 0.1, 1, 10, 50, and 100 mu M. Then the cultures were placed in a CO2-incubator in the dark. The viability of primary neuronal cultures was estimated on days 3 and 7 after photosensitizer application. Using confocal microscopy, we analyzed the rate of entry and subcellular localization of the tested agents in the primary neuronal cells. Statistical analysis was performed in SigmaPlot 11.0 (Systat Software Inc., USA) using ANOVA. Results. We analyzed the absorption and fluorescence spectra of the tested photosensitizers. Photosens and photodithazine showed the presence of absorption maximum in short- and long-wave spectral ranges. Hypericin was characterized by a complex spectrum with many peaks in both blue-violet and orange-red spectral ranges. Cell viability analysis revealed that high concentrations of photosensitizers caused a pronounced toxic effect on nervous cells. The most marked effect was shown for photodithazine. Photosens exhibited the lowest accumulation rate in primary neuronal cells. Photosens and hypericin were found to have a high phototoxic effect on glioma, and demonstrated low dark toxicity for normal brain cells. Conclusion. The photosensitizers hypericin and photosens are the least toxic for nervous tissue, though effectively penetrating in tumor cells. These properties enable to consider them as prospective photodynamic agents for clinic

Human serum albumin nanoparticles loaded with phthalocyanine dyes for potential use in photodynamic therapy of atherosclerotic plaques

Diseases caused by obstruction or rupture of vulnerable plaques in the arterial walls such as cardiovascular infarction or stroke are the leading cause of death in the world. In the present work, we developed human serum albuminnanoparticles loaded by physisorption with zinc phthalocyanine, TT1, mainly used for industrial application as near-infrared photosensitizer and compared these to HSA NPsloaded with the well-known silicone phthalocyanine (Pc4). The use of NIR light allows for better tissue penetration, while the use of nanoparticles permitshigh local concentrations. The particles were characterized and tested for toxicity and stability as well as for their potential use as a contrast agent and NIR photosensitizer for photodynamic therapy in cardiovascular disease. We focused on the distribution of the nanoparticles in RAW264.7macrophage cells and atherosclerotic mice. The nanoparticles had an average size of 120 nm according todynamic light scattering, good loading capacity for zinc phthalocyanine,and satisfying stability in 50% (v/v) fetal bovine serum for 8 hours and in an aqueous environment at 4°C for 4–6 weeks. Under light irradiation we found a high production of singlet oxygen and the products showed no dark toxicity in vitro with macrophages(the target cells in vulnerable plaques),but at a low μg/mL nanoparticleconcentration killed efficiently the macrophagesupon LED illumination. Injection of the contrast agentin atherosclerotic mice led to a visible fluorescence signal of zinc phthalocyaninein the atherosclerotic plaque at 30 minutes and in the lungs with afast clearance of the nanoparticles. Zinc phthalocyanine loaded human serum albumin nanoparticles present an interesting candidate for the visualization and potentially photodynamictreatment of macrophages in atherosclerotic plaquesThe research leading to these results has received funding from FP7-NMP CosmoPHOS-Nano under grant agreement No. 310337. Additional funding was received by the Spanish groups from MINECO (CTQ2017-85393-P) and ERA-NET/MINECO EuroNanoMed2017-191 / PCIN-2017-04

Efficacy of Combined 5-Fluorouracil and Photodynamic Therapy in Glioma Spheroids

Standard treatment regimens consisting of surgery, radiation and chemotherapy have proven ineffective for the treatment of high-grade gliomas such as glioblastoma multiforme (GBM). An effective cure requires elimination of nests of tumor cells that have migrated from the resection margin and infiltrated normal brain. A number of localized therapies, including light-based approaches such as photodynamic therapy (PDT) and photochemical internalization (PCI) are currently under investigation for the management of GBM patients. Several studies have demonstrated a high degree of synergy between PDT and bleomycin, via the PCI mechanism, in a variety of in vitro and in vivo models, including glioma cell lines. The purpose of this study was to examine the efficacy of combined treatments consisting of PDT and the chemotherapeutic agent, 5-fluorouracil (5-FU) in a 3-dimensional spheroid model consisting of F98 rat glioma cells. Spheroids were incubated with a photosensitizer (aluminum phthalocyanine disulfonate; AlPcS2a) and irradiated with 670 nm laser light. Three different wash protocols (0, 4 and 24 h) were employed to determine whether any observed interactions between PDT and 5-FU could be attributed to the PCI mechanism, or were simply due to different cytotoxic pathways of the two treatment modalities. Although the combined PDT + 5-FU treatments resulted in greater suppression of spheroid growth compared to either treatment alone, no statistically significant differences in growth effects were observed between 0 and 4 h wash protocols suggesting that the combined treatment effects were due to different mechanisms of cytotoxicity, rather than a PCI effect

Overview on topical 5-ALA photodynamic therapy use for non melanoma skin cancers

Ultraviolet radiation (UV) contributes to a variety of skin diseases including inflammation, degenerative aging, and cancer. Historically, humans have been exposed to UV radiation mainly through occupational exposure; recreational UV exposure, however, has increased dramatically in recent years, because of outdoor leisure activities and to purposely tan for cosmetic purposes. Both UVB and UVA radiation have been shown to cause DNA damage and immunosuppression, the important forms of biological damage that lead to NMSC. Nonmelanoma skin cancer (NMSC) is the most common malignancy, whose public health significance is often unrecognized which continues to grow at an alarming rate, becoming an occupational disease. Available treatments alternative to surgery include photodynamic therapy, electrochemotherapy, cryotherapy, ablative lasers, 5-fluorouracil, imiquimod, ingenol mebutate, and diclofenac. Among these, photodynamic therapy is a noninvasive technique with excellent cosmetic outcome and good curative results, when used in initial stages of skin cancers for superficial lesions. It is administered under numerous and significantly varied regimens and there are a wide range of cure rates reported, permitting treatment of large and multiple lesions with excellent cosmetic results. This is an overview of photodynamic applications especially for the treatment of NMSC, with a short focus on daylight modality. © 2014 Carmen Cantisani et al

Immobilized photosensitizers for antimicrobial applications

Photodynamic antimicrobial chemotherapy (PACT) is a very promising alternative to conventional antibiotics for the efficient inactivation of pathogenic microorganisms; this is due to the fact that it is virtually impossible for resistant strains to develop due to the mode of action employed. PACT employs a photosensitizer, which preferentially associates with the microorganism, and is then activated with non-thermal visible light of appropriate wavelength(s) to generate high localized concentrations of reactive oxygen species (ROS), inactivating the microorganism. The concept of using photosensitizers immobilized on a surface for this purpose is intended to address a range of economic, ecological and public health issues. Photosensitising molecules that have been immobilized on solid support for PACT applications are described herein. Different supports have been analyzed as well as the target microorganism and the effectiveness of particular combinations of support and photosensitiser

Trojan Horse nanotheranostics with dual transformability and multifunctionality for highly effective cancer treatment.

Nanotheranostics with integrated diagnostic and therapeutic functions show exciting potentials towards precision nanomedicine. However, targeted delivery of nanotheranostics is hindered by several biological barriers. Here, we report the development of a dual size/charge- transformable, Trojan-Horse nanoparticle (pPhD NP) for delivery of ultra-small, full active pharmaceutical ingredients (API) nanotheranostics with integrated dual-modal imaging and trimodal therapeutic functions. pPhD NPs exhibit ideal size and charge for drug transportation. In tumour microenvironment, pPhD NPs responsively transform to full API nanotheranostics with ultra-small size and higher surface charge, which dramatically facilitate the tumour penetration and cell internalisation. pPhD NPs enable visualisation of biodistribution by near-infrared fluorescence imaging, tumour accumulation and therapeutic effect by magnetic resonance imaging. Moreover, the synergistic photothermal-, photodynamic- and chemo-therapies achieve a 100% complete cure rate on both subcutaneous and orthotopic oral cancer models. This nanoplatform with powerful delivery efficiency and versatile theranostic functions shows enormous potentials to improve cancer treatment

Laser-induced generation of singlet oxygen and its role in the cerebrovascular physiology

For over 55 years, laser technology has expanded from laboratory research to widespread fields, for example telecommunication and data storage amongst others. Recently application of lasers in biology and medicine presents itself as one of the emerging areas. In this review, we will outline the recent advances in using lasers for the generation of singlet oxygen, traditionally used to kill tumour cells or induce thrombotic stroke model due to damage vascular effects. Over the last two decade, completely new results on cerebrovascular effects of singlet oxygen generated during photodynamic therapy (PDT) have been shown alongside promising applications for delivery of drugs and nanoparticles into the brain for therapy of brain cancer. Furthermore, a "gold key” has been found to overcome the limitations of PDT, such as low light penetration and high toxicity of photosensitizers, by direct generation of singlet oxygen using quantum-dot laser diodes emitting in the near infrared (NIR) spectral range. It is our motivation to highlight these pioneering results in this review, to improve understanding of the biological role of singlet oxygen and to provide new perspectives for improving clinical application of laser based therapy in further research