Electric field-assisted delivery of photofrin to human breast carcinoma cells

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

Effects of Nanosecond Pulsed Electric Field on Immune Checkpoint Receptors in Melanoma Cells

Checkpoint molecules such as PD-1, LAG-3, and TIM-3 are currently under extensive investigation for their roles in the attenuation of the immune response in cancer. Various methods have been applied to overcome the challenges in this field. This study investigated the effects of nanosecond pulsed electric field (nsPEF) treatment on the expression of immune checkpoint molecules in A375 and C32 melanoma cells. The researchers found that the nsPEF treatment was able to enhance membrane permeabilization and morphological changes in the cell membrane without being cytotoxic. We found that the effects of nsPEFs on melanoma included (1) the transport of vesicles from the inside to the outside of the cells, (2) cell contraction, and (3) the migration of lipids from inside the cells to their peripheries. The treatment increased the expression of PD-1 checkpoint receptors. Furthermore, we also observed potential co-localization or clustering of MHC class II and PD-1 molecules on the cell surface and the secretion of cytokines such as TNF-α and IL-6. These findings suggest that nsPEF treatment could be a viable approach to enhance the delivery of therapeutic agents to cancer cells and to modulate the tumor microenvironment to promote an antitumor immune response. Further studies are needed to explore the mechanisms underlying these effects and their impacts on the antitumor immune response, and to investigate the potential of nsPEF treatment in combination with immune checkpoint inhibitors to improve clinical outcomes for cancer patients.

Photothermal Propelling and Pyroelectric Potential-Promoted Cell Internalization of Janus Nanoparticles and Pyroelectrodynamic Tumor Therapy

Cancer phototherapy experiences limitations in tissue diffusion and cell internalization of phototherapeutic agents and dose-dependent side effects. Herein, Janus pyroelectric nanoparticles (NPs) are designed to generate self-powered motion and built-in electric fields to overcome the delivery barriers. Polydopamine (PDA) layers are partially coated on tetragonal BaTiO3 (tBT) NPs to prepare Janus tBT@PDA, and Au NPs are deposited on the PDA caps to obtain Janus tBT@PDA-Au NPs. Near-infrared (NIR) illumination of tBT@PDA-Au builds in situ pyroelectric potentials on NPs, which selectively affect the membrane potential of tumor cells rather than normal cells to enhance tumor cell internalization and produce reactive oxygen species (ROS) for pyroelectric dynamic therapy (PEDT). The asymmetric photothermal effect of the Janus NPs creates thermophoretic force to propel NP motion, which enhances tumor diffusion and cellular uptake of NPs and boosts cytotoxicity and intracellular ROS levels. The inoculation of Au NPs increases the photothermal effect, exhibits larger motion velocities, produces higher pyroelectric potentials, and elevates cellular uptake rates, resulting in significant induction of tumor cell apoptosis, suppression of tumor growth, and extension of animal survival. Thus, the concise design of tBT@PDA-Au/NIR treatment has achieved thermophoretic motion-promoted tissue diffusion, built-in electric field-enhanced cell internalization, and photothermal/PEDT-synergized antitumor efficacy.

J, M.D.P. DE. C, RAJENDRAM S. Photodynamic Therapy : An Overview and Insights into a Prospective Mainstream Anticancer Therapy

Photodynamic therapy (PDT) procedure has minimum invasiveness in contrast to conventional anticancer surgical procedures. Although clinically approved a few decades ago, it is not commonly used due to its poor efficacy, mainly due to poor light penetration into deeper tissues. PDT uses a photosensitizer (PS), which is photoactivated on illumination by light of appropriate wavelength and oxygen in the tissue, leading to a series of photochemical reactions producing reactive oxygen species (ROS) triggering various mechanisms resulting in lethal effects on tumor cells. This review looks into the fundamental aspects of PDT, such as photochemistry, photobiological effects, and the current clinical applications in the light of improving PDT to become a mainstream therapeutic procedure against a broad spectrum of cancers and malignant lesions. The side effects of PDT, both early and late-onset, are elaborated on in detail to highlight the available options to minimize side effects without compromising therapeutic efficacy. This paper summarizes the benefits, drawbacks, and limitations of photodynamic therapy along with the recent attempts to achieve improved therapeutic efficacy via monitoring various cellular and molecular processes through fluorescent imagery aided by suitable biomarkers, prospective nanotechnology-based targeted delivery methods, the use of scintillating nanoparticles to deliver light to remote locations and also combining PDT with conventional anticancer therapies have opened up new dimensions for PDT in treating cancers. This review inquires and critically analyses prospective avenues in which a breakthrough would finally enable PDT to be integrated into mainstream anticancer therapy.

Micro- and Nanosecond Pulses Used in Doxorubicin Electrochemotherapy in Human Breast and Colon Cancer Cells with Drug Resistance

(1) Background: Pulsed electric field (PEF) techniques are commonly used to support the delivery of various molecules. A PEF seems a promising method for low permeability drugs or when cells demonstrate therapy resistance and the cell membrane becomes an impermeable barrier. (2) Methods: In this study, we have used doxorubicin-resistant and sensitive models of human breast cancer (MCF-7/DX, MCF-7/WT) and colon cancer cells (LoVo, LoVoDX). The study aimed to investigate the susceptibility of the cells to doxorubicin (DOX) and electric fields in the 20–900 ns pulse duration range. The viability assay was utilized to evaluate the PEF protocols’ efficacy. Cell confluency and reduced glutathione were measured after PEF protocols. (3) Results: The obtained results showed that PEFs significantly supported doxorubicin delivery and cytotoxicity after 48 and 72 h. The 60 kV/cm ultrashort pulses × 20 ns × 400 had the most significant cytotoxic anticancer effect. The increase in DOX concentration provokes a decrease in cell viability, affected cell confluency, and reduced GSSH when combined with the ESOPE (European Standard Operating Procedures of Electrochemotherapy) protocol. Additionally, reactive oxygen species after PEF and PEF-DOX were detected. (4) Conclusions: Ultrashort electric pulses with low DOX content or ESOPE with higher DOX content seem the most promising in colon and breast cancer treatment.

Implications of photodynamic cancer therapy: an overview of PDT mechanisms basically and practically

BACKGROUND

Tumor eradication is one of the most important challengeable categories in oncological studies. In this account, besides the molecular genetics methods including cell therapy, gene therapy, immunotherapy, and general cancer therapy procedures like surgery, radiotherapy, and chemotherapy, photodynamic adjuvant therapy is of great importance. Photodynamic therapy (PDT) as a relatively noninvasive therapeutic method utilizes the irradiation of an appropriate wavelength which is absorbed by a photosensitizing agent in the presence of oxygen. In this procedure, a series of events lead to the direct death of malignant cells such as damage to the microvasculature and also the induction of a local inflammatory function. PDT has participated with other treatment modalities especially in the early stage of malignant tumors and has resulted in decreasing morbidity besides improving survival rate and quality of life. High spatial resolution of PDT has attracted considerable attention in the field of image-guided photodynamic therapy combined with chemotherapy of multidrug resistance cancers. Although PDT outcomes vary across the different tumor types, minimal natural tissue toxicity, minor systemic effects, significant reduction in long-term disease, lack of innate or acquired resistance mechanisms, and excellent cosmetic effects, as well as limb function, make it a valuable treatment option for combination therapies.

SHORT CONCLUSION

In this review article, we tried to discuss the potential of PDT in the treatment of some dermatologic and solid tumors, particularly all its important mechanisms.

Photodynamic Therapy Review: Principles, Photosensitizers, Applications, and Future Directions

Photodynamic therapy (PDT) is a minimally invasive therapeutic modality that has gained great attention in the past years as a new therapy for cancer treatment. PDT uses photosensitizers that, after being excited by light at a specific wavelength, react with the molecular oxygen to create reactive oxygen species in the target tissue, resulting in cell death. Compared to conventional therapeutic modalities, PDT presents greater selectivity against tumor cells, due to the use of photosensitizers that are preferably localized in tumor lesions, and the precise light irradiation of these lesions. This paper presents a review of the principles, mechanisms, photosensitizers, and current applications of PDT. Moreover, the future path on the research of new photosensitizers with enhanced tumor selectivity, featuring the improvement of PDT effectiveness, has also been addressed. Finally, new applications of PDT have been covered.

Investigating the photodynamic efficacy of chlorin e6 by millisecond pulses in metastatic melanoma cells

Melanoma is considered the most aggressive type of skin cancer, still without effective treatment. Thus, alternative therapeutic methods are still in demand, and electroporation-supported photodynamic therapy (EP-PDT) of cancer cells seems a promising approach. New developments in EP-PDT aim at enhanced tumor selectivity and biocompatibility by applying a second-generation photosensitizer, i.e., Chlorin e6 (Ce6). We have verified the improved photodynamic effect of Ce6 on skin cancer melanoma (Me45) cells and control (CHO-K1) cells. In this study, we applied 1 or 5 pulses of 10 ms duration and assessed the EP-PDT effect with a variety of tests, such as singlet oxygen scavenger (ABMDMA) photooxidation, oxidoreductive potential measurements, kinetic measurements with fluorescent microscopy, photosensitizer uptake studies, lipid peroxidation level, and actin fibers organization. The optimization of photosensitizer uptake as a function of temperature was also performed. Our results indicated efficient Ce6 delivery into Me45 cells and good photodynamic efficiency enhanced by the electroporation of cancer cells.

Doxorubicin Assisted by Microsecond Electroporation Promotes Irreparable Morphological Alternations in Sensitive and Resistant Human Breast Adenocarcinoma Cells

Electroporation increases the transmembrane transport of molecules. The combination of electric pulses with cytostatic compounds is beneficial for cancer treatment. Doxorubicin (DOX) is a commonly used chemotherapeutic anticancer drug. Its fluorescence properties enable the investigation of drug distribution and metabolism. In this study, doxorubicin was enhanced by electroporation to eliminate cancer cells more effectively. The influence of electroporation on the drug uptake was evaluated in two cell lines: MCF-7/WT and MCF-7/DOX. The intracellular localization of doxorubicin and its impact on the intracellular structure organization were examined under a confocal microscope. Cellular effects were examined with the 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test that estimates the rate of metabolism in viable cells. The ultrastructure (TEM) of tumor cells subjected to the electric field was analyzed. An enhanced doxorubicin efficacy was observed in MCF-7/DOX cells after combination with electroporation. The response of the resistant cell line was revealed to be more sensitive to electric pulses. Electroporation-based methods may be attractive for cancer treatment in human breast adenocarcinoma, especially with acquired resistance. Electroporation enables a reduction of the effective dose of the drugs and the exposure time in this type of cancer, diminishing side effects of the systemic therapy.

Photodynamic therapy - mechanisms, photosensitizers and combinations

Photodynamic therapy (PDT) is a modern and non-invasive form of therapy, used in the treatment of non-oncological diseases as well as cancers of various types and locations. It is based on the local or systemic application of a photosensitive compound - the photosensitizer, which is accumulated in pathological tissues. The photosensitizer molecules absorb the light of the appropriate wavelength, initiating the activation processes leading to the selective destruction of the inappropriate cells. The photocytotoxic reactions occur only within the pathological tissues, in the area of photosensitizer distribution, enabling selective destruction. Over the last decade, a significant acceleration in the development of nanotechnology has been observed. The combination of photosensitizers with nanomaterials can improve the photodynamic therapy efficiency and eliminate its side effects as well. The use of nanoparticles enables achievement a targeted method which is focused on specific receptors, and, as a result, increases the selectivity of the photodynamic therapy. The object of this review is the anticancer application of PDT, its advantages and possible modifications to potentiate its effects.

On the in vivo photochemical rate parameters for PDT reactive oxygen species modeling

Photosensitizer photochemical parameters are crucial data in accurate dosimetry for photodynamic therapy (PDT) based on photochemical modeling. Progress has been made in the last few decades in determining the photochemical properties of commonly used photosensitizers (PS), but mostly in solution or in vitro. Recent developments allow for the estimation of some of these photochemical parameters in vivo. This review will cover the currently available in vivo photochemical properties of photosensitizers as well as the techniques for measuring those parameters. Furthermore, photochemical parameters that are independent of environmental factors or are universal for different photosensitizers will be examined. Most photosensitizers discussed in this review are of the type II (singlet oxygen) photooxidation category, although type I photosensitizers that involve other reactive oxygen species (ROS) will be discussed as well. The compilation of these parameters will be essential for ROS modeling of PDT.

Membrane Permeabilization of Pathogenic Yeast in Alternating Sub-microsecond Electromagnetic Fields in Combination with Conventional Electroporation

Recently, a novel contactless treatment method based on high-power pulsed electromagnetic fields (PEMF) was proposed, which results in cell membrane permeabilization effects similar to electroporation. In this work, a new PEMF generator based on multi-stage Marx circuit topology, which is capable of delivering 3.3 T, 0.19 kV/cm sub-microsecond pulses was used to permeabilize pathogenic yeast Candida albicans separately and in combination with conventional square wave electroporation (8-17 kV/cm, 100 μs). Bursts of 10, 25, and 50 PEMF pulses were used. The yeast permeabilization rate was evaluated using flow cytometric analysis and propidium iodide (PI) assay. A statistically significant (P < 0.05) combinatorial effect of electroporation and PEMF treatment was detected. Also the PEMF treatment (3.3 T, 50 pulses) resulted in up to 21% loss of yeast viability, and a dose-dependent additive effect with pulsed electric field was observed. As expected, increase of the dB/dt and subsequently the induced electric field amplitude resulted in a detectable effect solely by PEMF, which was not achievable before for yeasts in vitro.

Cell Membrane Transport Mechanisms: Ion Channels and Electrical Properties of Cell Membranes

Cellular life strongly depends on the membrane ability to precisely control exchange of solutes between the internal and external (environmental) compartments. This barrier regulates which types of solutes can enter and leave the cell. Transmembrane transport involves complex mechanisms responsible for passive and active carriage of ions and small- and medium-size molecules. Transport mechanisms existing in the biological membranes highly determine proper cellular functions and contribute to drug transport. The present chapter deals with features and electrical properties of the cell membrane and addresses the questions how the cell membrane accomplishes transport functions and how transmembrane transport can be affected. Since dysfunctions of plasma membrane transporters very often are the cause of human diseases, we also report how specific transport mechanisms can be modulated or inhibited in order to enhance the therapeutic effect.

The Effect of Millisecond Pulsed Electric Fields (msPEF) on Intracellular Drug Transport with Negatively Charged Large Nanocarriers Made of Solid Lipid Nanoparticles (SLN): In Vitro Study

Drug delivery technology is still a dynamically developing field of medicine. The main direction in nanotechnology research (nanocarriers, nanovehicles, etc.) is efficient drug delivery to target cells with simultaneous drug reduction concentration. However, nanotechnology trends in reducing the carrier sizes to several nanometers limit the volume of the loaded substance and may pose a danger of uncontrolled access into the cells. On the other hand, nanoparticles larger than 200 nm in diameter have difficulties to undergo rapid diffusional transport through cell membranes. The main advantage of large nanoparticles is higher drug encapsulation efficiency and the ability to deliver a wider array of drugs. Our present study contributes a new approach with large Tween 80 solid lipid nanoparticles SLN (i.e., hydrodynamic GM-SLN-glycerol monostearate, GM, as the lipid and ATO5-SLNs-glyceryl palmitostearate, ATO5, as the lipid) with diameters DH of 379.4 nm and 547 nm, respectively. They are used as drug carriers alone and in combination with electroporation (EP) induced by millisecond pulsed electric fields. We evaluate if EP can support the transport of large nanocarriers into cells. The study was performed with two cell lines: human colon adenocarcinoma LoVo and hamster ovarian fibroblastoid CHO-K1 with coumarin 6 (C6) as a fluorescent marker for encapsulation. The biological safety of the potential treatment procedure was evaluated with cell viability after their exposure to nanoparticles and EP. The EP efficacy was evaluated by FACS method. The impact on intracellular structure organization of cytoskeleton was visualized by CLSM method with alpha-actin and beta-tubulin. The obtained results indicate low cytotoxicity of both carrier types, free and loaded with C6. The evaluation of cytoskeleton proteins indicated no intracellular structure damage. The intracellular uptake and accumulation show that SLNs do not support transport of C6 coumarin. Only application of electroporation improved the transport of encapsulated and free C6 into both treated cell lines.

BODIPY appended copper(ii) complexes for cellular imaging and singlet oxygen mediated anticancer activity in visible light

BODIPY-appended copper(ii) complexes are for cellular imaging and visible light-induced remarkable PDT activity in HeLa/MCF-7 cells with¹O₂-mediated cellular apoptosis.

The photodynamic effect of far-red range phthalocyanines (AlPc and Pc green) supported by electropermeabilization in human gastric adenocarcinoma cells of sensitive and resistant type

INTRODUCTION

Electroporation (EP) is commonly applied for effective drug transport thorough cell membranes based on the application of electromagnetic field. When applied with cytostatics, it is called electrochemotherapy (ECT) - a quite new method of cancer treatment. A high-voltage pulse causes the formation of temporary pores in the cell membrane which create an additional way for the intracellular drug transport. In the current work, EP was effectively merged with the already known photodynamic therapy (PDT) to selective photosensitizers' delivery to diseased tissue. The application of electroporation can reduce the dose of applied drug.

RESEARCH OBJECTIVE

The aim of research was to evaluate the effectiveness of photodynamic reaction using two near infrared cyanines (AlPc and Pc green) combined with electroporation in two human gastric adenocarcinoma cell lines.

MATERIALS AND METHODS

Two human cell lines - EPG85-257P (parental) and EPG85-257RDB (resistant to daunorubicin) - of gastric cancer were used. The effect of two photosensitizers (aluminum 1,8,15,22-tetrakis(-phenylthio)-29H,31H-phthalocyanine chloride and Phthalocyanine green) was investigated. The efficiency of EP parameters was assessed by propidium iodide uptake. The viability assay was applied to analyse EP, PDT and EP-PDT effect. Cyanine localization was determined by confocal microscopy. Immunocytochemical evaluation of manganese superoxide dismutase and glutathione S-transferase-pi was determined after applied therapies.

RESULTS

PDT in combination with EP affected the viability of EPG85-257P and EPG85-257RDB cells negatively while both cyanine were used. The most evident changes were observed in the following concentrations: 15, 10 and 5μM. The optimal field strength for enhanced EP-PDT was 800 and 1200V/cm. AlPc distributed selectively in the lysosomes of parental cell line.

CONCLUSIONS

PDT, enhanced by EP, caused decreased viability when compared to the application of PDT alone. Both phthalocyanines found to be more effective after electroporation. Due to the low concentration of light-sensitive compounds and safety of electroporation itself, a treatment plan can be an alternative therapeutic modality against gastric adenocarcinomas.

Electroporation enhances antimicrobial photodynamic therapy mediated by the hydrophobic photosensitizer, hypericin

The effective transport of photosensitizers (PS) across the membrane and the intracellular accumulation of PS are the most crucial elements in antimicrobial photodynamic therapy (aPDT). However, due to the morphological complexity of Gram-negative bacteria the penetration of PS is limited, especially hydrophobic PS. Electroporation (EP) could increase the effectiveness of aPDT, by promoting the formation of transient pores that enhance the permeability of the bacterial membrane to PS. In this study we evaluated the combination of aPDT mediated by the hydrophobic PS, hypericin and EP (aPDT/EP) against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. These bacteria were exposed to light (590 nm) in the presence of hypericin (4 μM), following electroporation. The results showed that aPDT/EP inactivated 3.67 logs more E. coli and 2.65 logs more S. aureus than aPDT alone. Based on these results we suggest that EP can potentiate the aPDT effect.

Cyanines in photodynamic reaction assisted by reversible electroporation--in vitro study on human breast carcinoma cells

BACKGROUND

Ineffective drug delivery is a vast problem of anticancer therapies. The aim of this study was to investigate the possibility of enhancement of cyanines transport through the cell membrane by electroporation and to evaluate a photodynamic activity of these compounds.

METHODS

We evaluated in vitro the effectiveness of photodynamic reaction with cyanines on breast adenocarcinoma cells (MCF-7/WT) and normal Chinese hamster ovary cells (CHO) lacking voltage-dependent ion channels, alone and combined with electropermeabilization. Among six cyanines tested, two compounds could be indicated as good therapeutic candidates: IR-775 and IR-786. Cellular effects were assessed with MTT assay reporting cell mitochondrial activity and with SRB assay based on the measurement of cellular protein content. Cyanines localization was observed with confocal microscope.

RESULTS

Photodynamic reaction of MCF-7/WT cells with IR-775 and IR-786 did not result in cellular dysfunction. Electric field intensities and pulse duration, non-toxic for cells, significantly increased photocytotoxicity of the cyanines after electropermeabilization with IR-775 and IR-786. Much shorter exposure times were efficient for cyanines in photodynamic reaction assisted by electroporation (10 min instead of 24h).

CONCLUSIONS

Our results indicate that electroporation of cancerous cells in the presence of cyanine dyes could increase the uptake of the photosensitizer, which correlates with a higher cytotoxicity in the breast adenocarcinoma cell line. Electroporation may be an attractive delivery system for photosensitizers in photodynamic therapy, enabling application of new compounds and reduction of drug dose and exposure time.