Microbubble based sonoporation — from the basics into clinical implications

Sonoporation is a rapidly developing novel technique serving for drug delivery and non-viral gene therapy. It is based on the interaction between microbubbles located in the surrounding of a cell and its membrane. The interaction is obtained by excitation of microbubbles with ultrasounds. This leads to reversible cell membrane poration. Depending on the intensity of ultrasounds, structure of microbubbles used in an experiment and different environmental factors, microbubbles can interact in two manners. First, in lower ultrasound intensities, stable cavitation – regular microbubbles oscillations due to changes in the environment pressure. Microbubbles have to be very close to a cell membrane, therefore, they are usually targeted to an antigen located on the cell membrane by antibodies. Consequently, microbubbles push and pull on the cell membrane and create microstreaming around it causing its disruption. Second, inertial cavitation, where in contrary to the previous one, oscillations cause rapid collapse of microbubbles, which creates shock waves and microjets for the same purpose. No matter in which manner prorated, cells tend to reseal their disrupted cell membrane. Ca2+ ions play a crucial role in the process as well as endo exocytosis. Sonoporation has proved to be an effective modality against different diseases, including variety of cancer types in of both laboratory and clinical studies

Signaling pathways in melanoma biology and new targeted therapeutic approaches

Despite the broad prevention programs and early detection and therapy progress, melanoma of skin is still responsible for 0.6% of deaths caused by tumour disease. Every year 300,000 patients are diagnosed and 60,000 die from the most malignant of skin cancer. Generally, melanoma is formed as a result of mutation of growth pathways responsible for proliferation and apoptosis. One of the most investigated pathway, mutated in 90% of melanomas, is RAS > RAF > MEK > ERK also known as mitogen-activated protein kinase (MAPK) pathway. The second one is phosphoinositide-3-OH kinase (PI3K) pathway. The better understanding of melanoma biology resulted in research of inhibitors, which can affect presented pathways and prevent uncontrolled proliferation of melanoma. The BRAF inhibitors vemurafenib and dabrafenib and MEK inhibitor trametinib seem to be the most successful ones. Recent advances in biology of melanoma provided new interesting therapeutic targets. One of the most inquiring is microphthalmia associated transcription factor (MITF), the principal regulator of melanocyte lineage. MITF perform the role of so-called ‘survival’ or ‘addiction’ oncogene. Moreover, the interleukin-1 receptor-associated kinases (IRAKs) might clarify the connection between the inflammatory environment and melanoma carcinogenesis. IRAKs play a key role as mediators of toll-like receptor (TLR) and interleukin-1 receptor (IL1R) in inflammation signalling processes. Moreover, it was observed that metformin cause cell cycle arrest in melanoma cells, secondly leading to activation of autophagy and apoptosis. Although due to targeted and immunotherapy the prognosis of patients with metastatic melanoma is incomparably better, melanoma in its advanced stadium is still predominantly lethal. Therefore, the most present research concentrates on acquired resistance against targeted therapy

How to Alleviate Cardiac Injury From Electric Shocks at the Cellular Level

Electric shocks, the only effective therapy for ventricular fibrillation, also electroporate cardiac cells and contribute to the high-mortality post-cardiac arrest syndrome. Copolymers such as Poloxamer 188 (P188) are known to preserve the membrane integrity and viability of electroporated cells, but their utility against cardiac injury from cardiopulmonary resuscitation (CPR) remains to be established. We studied the time course of cell killing, mechanisms of cell death, and protection with P188 in AC16 human cardiomyocytes exposed to micro- or nanosecond pulsed electric field (μsPEF and nsPEF) shocks. A 3D printer was customized with an electrode holder to precisely position electrodes orthogonal to a cell monolayer in a nanofiber multiwell plate. Trains of nsPEF shocks (200, 300-ns pulses at 1.74 kV) or μsPEF shocks (20, 100-μs pulses at 300 V) produced a non-uniform electric field enabling efficient measurements of the lethal effect in a wide range of the electric field strength. Cell viability and caspase 3/7 expression were measured by fluorescent microscopy 2–24 h after the treatment. nsPEF shocks caused little or no caspase 3/7 activation; most of the lethally injured cells were permeable to propidium dye already at 2 h after the exposure. In contrast, μsPEF shocks caused strong activation of caspase 3/7 at 2 h and the number of dead cells grew up to 24 h, indicating the prevalence of the apoptotic death pathway. P188 at 0.2–1% reduced cell death, suggesting its potential utility in vivo to alleviate electric injury from defibrillation

RECENT RESEARCH IN VLSI, MEMS AND POWER DEVICES WITH PRACTICAL APPLICATION TO THE ITER AND DREAM PROJECTS

Several MEMS (Micro Electro-Mechanical Systems) devices have been analysed and simulated. The new proposed model of SiC MPS (Merged PIN-Schottky) diodes is in full agreement with the real MPS devices. The real size DLL (Dynamic Lattice Liquid) simulator as well as the research on modelling and simulation of modern VLSI devices with practical applications have been presented. In the basis of experience in the field of ATCA (Advanced Telecommunications Computing Architecture) based systems a proof-of-concept DAQ (data acquisition) system for ITER (International Thermonuclear Experimental Reactor) have been proposed

Oxidative Effects during Irreversible Electroporation of Melanoma Cells—In Vitro Study

Irreversible electroporation (IRE) is today used as an alternative to surgery for the excision of cancer lesions. This study aimed to investigate the oxidative and cytotoxic effects the cells undergo during irreversible electroporation using IRE protocols. To do so, we used IRE-inducing pulsed electric fields (PEFs) (eight pulses of 0.1 ms duration and 2–4 kV/cm intensity) and compared their effects to those of PEFs of intensities below the electroporation threshold (eight pulses, 0.1 ms, 0.2–0.4 kV/cm) and the PEFs involving elongated pulses (eight pulses, 10 ms, 0.2–0.4 kV/cm). Next, to follow the morphology of the melanoma cell membranes after treatment with the PEFs, we analyzed the permeability and integrity of their membranes and analyzed the radical oxygen species (ROS) bursts and the membrane lipids’ oxidation. Our data showed that IRE-induced high cytotoxic effect is associated both with irreversible cell membrane disruption and ROS-associated oxidation, which is occurrent also in the low electric field range. It was shown that the viability of melanoma cells characterized by similar ROS content and lipid membrane oxidation after PEF treatment depends on the integrity of the membrane system. Namely, when the effects of the PEF on the membrane are reversible, aside from the high level of ROS and membrane oxidation, the cell does not undergo cell death

Atorvastatin Modulates the Efficacy of Electroporation and Calcium Electrochemotherapy

Electroporation is influenced by the features of the targeted cell membranes, e.g., the cholesterol content and the surface tension of the membrane. The latter is eventually affected by the organization of actin fibers. Atorvastatin is a statin known to influence both the cholesterol content and the organization of actin. This work analyzes the effects of the latter on the efficacy of electroporation of cancer cells. In addition, herein, electroporation was combined with calcium chloride (CaEP) to assess as well the effects of the statin on the efficacy of electrochemotherapy. Cholesterol-rich cell lines MDA-MB231, DU 145, and A375 underwent (1) 48 h preincubation or (2) direct treatment with 50 nM atorvastatin. We studied the impact of the statin on cholesterol and actin fiber organization and analyzed the cells’ membrane permeability. The viability of cells subjected to PEF (pulsed electric field) treatments and CaEP with 5 mM CaCl2 was examined. Finally, to assess the safety of the therapy, we analyzed the N-and E-cadherin localization using confocal laser microscopy. The results of our investigation revealed that depending on the cell line, atorvastatin preincubation decreases the total cholesterol in the steroidogenic cells and induces reorganization of actin nearby the cell membrane. Under low voltage PEFs, actin reorganization is responsible for the increase in the electroporation threshold. However, when subject to high voltage PEF, the lipid composition of the cell membrane becomes the regulatory factor. Namely, preincubation with atorvastatin reduces the cytotoxic effect of low voltage pulses and enhances the cytotoxicity and cellular changes induced by high voltage pulses. The study confirms that the surface tension regulates of membrane permeability under low voltage PEF treatment. Accordingly, to reduce the unfavorable effects of preincubation with atorvastatin, electroporation of steroidogenic cells should be performed at high voltage and combined with a calcium supply

Boosting the Immune Response—Combining Local and Immune Therapy for Prostate Cancer Treatment

Due to its slow progression and susceptibility to radical forms of treatment, low-grade PC is associated with high overall survival (OS). With the clinical progression of PC, the therapy is becoming more complex. The immunosuppressive tumor microenvironment (TME) makes PC a difficult target for most immunotherapeutics. Its general immune resistance is established by e.g., immune evasion through Treg cells, synthesis of immunosuppressive mediators, and the defective expression of surface neoantigens. The success of sipuleucel-T in clinical trials initiated several other clinical studies that specifically target the immune escape of tumors and eliminate the immunosuppressive properties of the TME. In the settings of PC treatment, this can be commonly achieved with radiation therapy (RT). In addition, focal therapies usually applied for localized PC, such as high-intensity focused ultrasound (HIFU) therapy, cryotherapy, photodynamic therapy (PDT), and irreversible electroporation (IRE) were shown to boost the anti-cancer response. Nevertheless, the present guidelines restrict their application to the context of a clinical trial or a prospective cohort study. This review explains how RT and focal therapies enhance the immune response. We also provide data supporting the combination of RT and focal treatments with immune therapies