Electroporation-induced changes in normal immature rat myoblasts (H9C2).

Application of a high electric field causes an electric shock to the heart. This is utilized in defibrillation to reestablish normal contraction rhythms during dangerous arrhythmias or in cardiac arrest. If shock-induced transmembrane potentials are large enough, they can cause tissue destruction due to irreversible electroporation (EP). Also electrochemotherapy of nearby tissues may have an adverse effect on the heart. Herein, we present experimental data on effects of electroporation in culture of cardiac cells (H9C2). The electric field was applied in short pulses of 25-3250 V/cm, 50 µs each. The viability of cells was tested by MTT assay after 24 hours. For detection of DNA fragmentation, associated with apoptosis, alkaline and neutral comet assays were performed after EP. Additionally phase contrast images of cells obtained directly after EP were analyzed. Although cell images indicated disruption of cell membranes after EP with high intensities, only a few percent of apoptotic cells and no necrotic effects in the cell nucleus could be observed in comet assay tests performed 2 hours post EP. MTT viability test showed that pulse intensities above 375 V/cm are destructive for myocytes viability.

Comparison of the influence of photodynamic reaction on the Me45 and MEWO cell lines in vitro.

AIM OF THE STUDY: Photodynamic therapy (PDT) is an approved, minimally invasive and highly selective therapeutic approach to a variety of tumors. It is based on specific photosensitizer accumulation in the tumor tissue, followed by irradiation with visible light. The photochemical interactions of the photosensitizer, light and molecular oxygen produce singlet oxygen and other reactive oxygen forms. The imbalance between ROS generation and antioxidant capacity of the body gives rise to oxidative stress in the cell, which initiates cell death in PDT. The aim of this study was to investigate the effect of photodynamic reactions in human melanoma cell lines. MATERIAL AND METHODS: Photofrin(®) (Ph) was used for the photodynamic reaction in vitro as a photosensitizer. The primary cell line was MEWO cell line (granular fibroblasts), derived from a human melanoma. As a recurrent cell line we used Me45 cell line, derived from a lymph node metastasis of skin melanoma. We compared cell viability (MTT assay) to determine the effectiveness of applied therapy. The intracellular distribution of photosensitizer (Photofrin) and localization of mitochondria (Mito-Tracker Green) were detected by confocal microscopy. RESULTS: We observed that Me45 and MEWO cell viability was dependent on the time of incubation after irradiation. In the recurrent cell line Ph accumulated mainly in the mitochondrial membranes and in MEWO cells also in the cytoplasm. The primary melanoma cell line exhibited significantly reduced cellular proliferation (below 50%) after photodynamic reaction with Ph. CONCLUSIONS: The applied photodynamic reaction was more effective in primary melanoma cells. Additionally, mitochondrial localization of Ph can lead to disturbances of mitochondrial transmembrane potential and finally to release of apoptotic proteins.

[Electroporation and its application]. / Ektroporacja i jej zastosowanie.

Electroporation (EP) is a modern and versatile method that allows the penetration of macromolecules from the intercellular space into cells by forming the channels, under the influence of electromagnetic field. In addition to natural channels and pumps, building cell membranes, resulting electropores an additional way for the transport of macromolecules. The use of this phenomenon has brought good results as a complement to traditional therapeutic methods of treatment during application of cytostatics. EP combination with chemotherapy has reduced the need for surgical intervention (rescue authority). Electroporation is particularly useful for cancer with multidrug resistance, where the dose that enters the interior of cancer cells is limited. Electroporation was also used in transfection of nucleic acids, in photodynamic therapy, cosmetology, as well as the consolidation of the food.

The potential role of photodynamic therapy in the treatment of malignant melanoma--an in vitro study.

BACKGROUND: Melanoma is the most severe of skin neoplasms as it may grow rapidly and metastasize. The application of photodynamic therapy (PDT) opens up new prospects in the treatment of this tumor. Numerous studies suggest that the exposure of tumor cells to PDT can lead to cellular and molecular mechanisms which mediate oxidative stress in cells. OBJECTIVES: The aim of this study was to evaluate in vitro the influence of photodynamic therapy on the human melanoma Me45 cell line. MATERIAL AND METHODS: Photofrin (Ph) was used as a photosensitizer. RESULTS: Viability studies have shown that there are significant differences between cells after PDT and cells without irradiation. After 24 hours of incubation with a 20 microg/ml concentration of Ph and with irradiation, less than 20% of the cells survived. In the control (without PDT), 65% of the cells survived. CONCLUSIONS: The mitochondrial localization of Ph is significant, as it may lead to disturbances of mitochondrial transmembrane potential and finally to apoptotic cell death. The expressions of manganese superoxide dismutase and heme oxygenase and the level of carbonyl and thiol groups are indicating factors for oxidative stress in Me45 cells.

Photo-oxidative action in MCF-7 cancer cells induced by hydrophobic cyanines loaded in biodegradable microemulsion-templated nanocapsules.

Searching for photodynamic therapy-effective nanocarriers which enable a photosensitizer to be selectively delivered to tumor cells with enhanced bioavailability and diminished dark cytotoxicity is of current interest. We have employed a polymer-based nanoparticle approach to encapsulate the cyanine-type photosensitizer IR-780 in poly(n-butyl cyanoacrylate) (PBCA) nanocapsules. The latter were fabricated by interfacial polymerization in oil-in-water (o/w) microemulsions formed by dicephalic and gemini saccharide-derived surfactants. Nanocarriers were characterized by SEM, AFM and DLS. The efficiency of PBCA nanocapsules as a potential system of photosensitizer delivery to human breast cancer cells was established by dark and photocytotoxicity as the function of the cellular mitochondria. The photodynamic effect of cyanine IR-780 was determined by investigation of oxidative stress markers. The nanocapsules were the main focus of our studies to examine their cellular uptake and dark and photocytotoxicity as the function of the cellular mitochondria as well as oxidative stress markers (i.e., lipid peroxidation and protein damage) in MCF-7/WT cancer cells. The effects of encapsulated IR-780 were compared with those of native photosensitizer. The penetration of the nanocapsules into cancer cells was visualized by CLSM and their uptake was estimated by FACS analysis. Cyanine IR-780 delivered in PBCA nanocapsules to MCF-7/WT cells retains its sensitivity upon photoirradiation and it is regularly distributed in the cell cytoplasm. The intensity of the photosensitizer-generated oxidative stress depends on IR-780 release from the effective uptake of polymeric nanocapsules and seems to remain dependent upon the surfactant structure in o/w microemulsion-based templates applied to nanocapsule fabrication.

ETM study of electroporation influence on cell morphology in human malignant melanoma and human primary gingival fibroblast cells.

OBJECTIVE: To estimate electroporation (EP) influence on malignant and normal cells. METHODS: Two cell lines including human malignant melanoma (Me-45) and normal human gingival fibroblast (HGFs) were used. EP parameters were the following: 250, 1 000, 1 750, 2 500 V/cm; 50 µs by 5 impulses for every case. The viability of cells after EP was estimated by MTT assay. The ultrastructural analysis was observed by transmission electron microscope (Zeiss EM 900). RESULTS: In the current study we observed the intracellular effect following EP on Me-45 and HGF cells. At the conditions applied, we did not observe any significant damage of mitochondrial activity in both cell lines treated by EP. Conversely, we showed that EP in some conditions can stimulate cells to proliferation. Some changes induced by EP were only visible in electron microscopy. In fibroblast cells we observed significant changes in lower parameters of EP (250 and 1 000 V/cm). After applying higher electric field intensities (2 500 V/cm) we detected many vacuoles, myelin-like bodies and swallowed endoplasmic reticulum. In melanoma cells such strong pathological modifications after EP were not observed, in comparison with control cells. The ultrastructure of both treated cell lines was changed according to the applied parameters of EP. CONCLUSIONS: We can claim that EP conditions are cell line dependent. In terms of the intracellular morphology, human fibroblasts are more sensitive to electric field as compared with melanoma cells. Optimal conditions should be determined for each cell line. Summarizing our study, we can conclude that EP is not an invasive method for human normal and malignant cells. This technique can be safely applied in chemotherapy for delivering drugs into tumor cells.

The effects of the electro-photodynamic in vitro treatment on human lung adenocarcinoma cells.

The effectiveness of the photodynamic therapy (PDT), a low-invasive and targeted therapy of cancer, could be intensified by increasing the intracellular transport of a photosensitizer. The electroporation is used to generate non-specific transient nanopores that facilitate local drug delivery into cells. Photodynamic therapy assisted by electroporation was tested in vitro on the human lung carcinoma cell line A549 by determining the mitochondrial cell function using the MTT assay. The photodynamic activity of the electro-photodynamic treatment (EPDT) with the hematoporphyrin derivative was evaluated in relation to the photodynamic method alone. The experiments show significantly increased efficiency of EPDT, which allows reducing drug doses and exposure time of the cells to the drug in standard PDT. The results have been confronted with the model based on van't Hoff equation. This showed that the growth fractions of cells after EPDT depend on the electric field according to the same relation as in case of electroporation alone.