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•Hypoxia reduces bleomycin cytotoxicity on intact hepatoma cells.•Efficacy of bleomycin electrochemotherapy is reduced 5.3-fold in hypoxia.•Cytotoxicity of bleomycin can be modulated ...1–2 h after cell electroporation.
Bleomycin, which is the most widely used drugs in electrochemotherapy, requires oxygen to be able to make single- or double-strand brakes in DNA. However, the concentration of oxygen in tumours can be lower than 1%. The aim of this study was to find out whether oxygen concentration in the medium in which cells loaded with bleomycin are incubated, affects the effectiveness of electrochemotherapy in vitro. Experiments were carried out on mouse hepatoma MH-22A cells. Cells were loaded with bleomycin by using a single square-wave electric pulse (2 kV/cm, 100 μs) under normoxic conditions, seeded into Petri dishes, and grown under normoxic and hypoxic conditions. Cell viability was determined by means of a colony-forming assay. We demonstrated that when cells loaded with bleomycin were incubated in hypoxia (0.2% O2), up to 5.3-fold higher concentrations of bleomycin were needed to kill them in comparison with cells grown in normoxia (18.7% O2).
With the absence of the three most common receptor targets, and with high vascularity and higher-grade tumors, triple-negative breast cancer (TNBC) is the most aggressive of all breast cancer ...subtypes and is in need of additional/alternative/novel treatment strategies. With ~ 15% of the over 2 million new cases each year, there is an unmet need to treat TNBC. MDA-MB-231, human TNBC cells, were treated with neem leaf extract (Neem) and eight, 1200 V/cm, 100 µs electric pulses (EP), and their viability and proteomic profiles were studied. With EP + Neem, a lower viability of 37% was observed after 24 h, compared to 85% in the neem-only samples, indicating the efficacy of the combinational treatment. The proteomics results indicated significant upregulation of 525 proteins and downregulation of 572 proteins, with a number of different pathways in each case. These include a diverse group of proteins, such as receptors, heat shock proteins, and many others. The upregulated TCA cycle and OXPHOS pathways and the downregulated DNA replication and ubiquitin-mediated proteolytic pathways were associated with effective cell death, demonstrating the potency of this treatment. Viability results reveal the efficacious anticancer effects of the EP + Neem combination, via growth inhibition, on TNBC cells. Proteomics studies could readily identify the effected protein pathways, and their corresponding genes, that are responsible for cell death. This represents a potential therapeutic strategy against TNBC when patients are refractory to standard treatments.
Two patients underwent percutaneous image-guided electrochemotherapy on blastic spine metastases involving posterior walls of the lumbar vertebral bodies with epidural extension. These treatments ...were performed safely under cone beam computed tomography. Local tumor control was obtained on the subsequent follow-up as well as pain relief and disability improvement. Electrochemotherapy might be considered for patients with thus far no other alternative in order to obtain tumor control and improvement in patients’ quality of life.
Squamous cell carcinoma is the most common malignancy that arises in the head-and-neck district. Traditional treatment could be insufficient in case of recurrent and/or metastatic cancers; for this ...reason, more selective and enhanced treatments are in evaluation in preclinical and clinical trials to increase in situ concentration of chemotherapy drugs promoting a selectively antineoplastic activity. Among all cancer treatment types (i.e., surgery, chemotherapy, radiotherapy), electroporation (EP) has emerged as a safe, less invasive, and effective approach for cancer treatment. Reversible EP, using an intensive electric stimulus (i.e., 1000 V/cm) applied for a short time (i.e., 100 μs), determines a localized electric field that temporarily permealizes the tumor cell membranes while maintaining high cell viability, promoting cytoplasm cell uptake of antineoplastic agents such as bleomycin and cisplatin (electrochemotherapy), calcium (Ca2+ electroporation), siRNA and plasmid DNA (gene electroporation). The higher intracellular concentration of antineoplastic agents enhances the antineoplastic activity and promotes controlled tumor cell death (apoptosis). As secondary effects, localized EP (i) reduces the capillary blood flow in tumor tissue (“vascular lock”), lowering drug washout, and (ii) stimulates the immune system acting against cancer cells. After years of preclinical development, electrochemotherapy (ECT), in combination with bleomycin or cisplatin, is currently one of the most effective treatments used for cutaneous metastases and primary skin and mucosal cancers that are not amenable to surgery. To reach this clinical evidence, in vitro and in vivo models were preclinically developed for evaluating the efficacy and safety of ECT on different tumor cell lines and animal models to optimize dose and administration routes of drugs, duration, and intensity of the electric field. Improvements in reversible EP efficacy are under evaluation for HNSCC treatment, where the focus is on the development of a combination treatment between EP-enhanced nanotechnology and immunotherapy strategies.
A 12-year-old female cockatiel (Nymphicus hollandicus) was presented with a squamous cell carcinoma involving the uropygial gland. Electrochemotherapy (ECT) as a minimally invasive treatment option ...was applied. The patient was anesthetized, a chemotherapeutic agent was injected intratumorally, and electrical pulses were delivered using plate and needle electrodes. In the first session of ECT cisplatin was used, and no change in tumor volume was observed during the following month. In a further 2 treatments 1 month apart, bleomycin was used. The tumor responded, and the mass became necrotic and eventually disappeared. Unfortunately, the tumorous mass reappeared after 3 months. Therefore, a fourth ECT using bleomycin was performed and the tumor completely regressed. No tumor growth was seen in 18 months after the last therapy. This report presents the clinical significance of ECT using cisplatin and bleomycin in treatment of uropygial gland squamous cell carcinoma in a cockatiel.
To evaluate the appearance and size of ablation zones in gadoxetic-acid-enhanced magnetic resonance imaging (MRI) during the first year after irreversible electroporation (IRE) of primary or ...secondary hepatic malignancies and to investigate potential correlations to clinical features.
The MRI-appearance of the ablation area was assessed 1-3 days, 6 weeks, 3 months, 6 months, 9 months and 1 year after IRE. The size of the ablation zone and signal intensities of each follow-up control were compared. Moreover, relationships between clinical features and the MRI-appearance of the ablation area 1-3 days after IRE were analyzed.
The ablation zone size decreased from 5.6 ± 1.4 cm (1-3 days) to 3.7±1.2 cm (1 year). A significant decrease of central hypointensities was observed in T2-blade- (3 months), T2 haste- (6 weeks; 3 months; 6 months; 1 year), T1 arterial phase- (3 months; 1 year), and diffusion-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). The unenhanced T1-sequences showed significantly increasing central hypointensities (6 weeks; 3 months; 6 months; 9 months; 1 year). Significantly increasing peripheral hypointensities were detected in T1 arterial phase- (3 months; 6 months; 9 months; 1 year) and in T1 portal venous phase-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). Peripheral hypointensities of unenhanced T1-sequences decreased significantly 1 year after IRE. 1-3 days after IRE central T1 portal venous hypo- or isointensities were detected significantly more often than hyperintensities, if more than 3 IRE electrodes were used.
Hepatic IRE results in continuous reduction of ablation zone size during the first postinterventional year. In addition to centrally decreasing T1-signal and almost steadily increasing signal in the enhanced T2 haste-, diffusion- and T1 arterial phase-sequences, there is a trend toward long-term decreasing T1 arterial- and portal venous MRI-signal intensity of the peripheral ablation area, probably representing a region of reversible electroporation.
To increase electrochemotherapy (ECT) applicability, the effectiveness of new drugs is being tested in combination with electroporation. Among them two ruthenium(III) compounds, (imH)
trans
-RuCl
4
...(im)(DMSO-S) (NAMI-A) and Na
trans
-RuCl
4
(ind)
2
(KP1339), proved to possess increased antitumor effectiveness when combined with electroporation. The objective of our experimental work was to determine influence of electroporation on the cytotoxic and antitumor effect of a ruthenium(III) compound with hampered transmembrane transport, (imH)
trans
-RuCl
4
(im)
2
(KP418) in vitro and in vivo and to determine changes in metastatic potential of cells after ECT with KP418 in vitro. In addition, platinum compound cisplatin (CDDP) and ruthenium(III) compound NAMI-A were included in the experiments as reference compounds. Our results show that electroporation leads to increased cellular accumulation and cytotoxicity of KP418 in murine melanoma cell lines with low and high metastatic potential, B16-F1 and B16-F10, but not in murine fibrosarcoma cell line SA-1 in vitro which is probably due to variable effectiveness of ECT in different cell lines and tumors. Electroporation does not potentiate the cytotoxicity of KP418 as prominently as the cytotoxicity of CDDP. We also showed that the metastatic potential of cells which survived ECT with KP418 or NAMI-A does not change in vitro: resistance to detachment, invasiveness, and re-adhesion of cells after ECT is not affected. Experiments in murine tumor models B16-F1 and SA-1 showed that ECT with KP418 does not have any antitumor effect while ECT with CDDP induces significant dose-dependent tumor growth delay in the two tumor models used in vivo.
Electrochemotherapy (ECT) is the combination of transient pore formation following electric pulse application with the administration of cytotoxic drugs, which enhances the cytotoxic effect of the ...applied agent due to membrane changes and permeabilization. Although EP represents an established therapeutic option for solid malignancies, recent advances shift to the investigation of non-cytotoxic agents, such as calcium, which can also induce cell death. The present study aims to evaluate the cytotoxic effect, the morphological changes in tumor spheroids, the effect on the cell viability, and the cell-specific growth rate following calcium electroporation (CaEP) in uveal melanoma (UM) 2D monolayer cell cultures as well as in 3D tumor spheroid models. The experiments were conducted in four cell lines, UM92.1, Mel270, and two primary UM cell lines, UPMD2 and UPMM3 (UPM). The 2D and 3D UM cell cultures were electroporated with eight rectangular pulses (100 µs pulse duration, 5 Hz repetition frequency) of a 1000 V/cm pulse strength alone or in combination with 0.11 mg/mL, 0.28 mg/mL, 0.55 mg/mL or 1.11 mg/mL calcium chloride or 1.0 µg/mL or 2.5 µg/mL bleomycin. The application of calcium chloride alone induced an ATP reduction only in the UM92.1 2D cell cultures. Calcium alone had no significant effect on ATP levels in all four UM spheroids. A significant decrease in the intracellular adenosine triphosphate (ATP) level was documented in all four 2D and 3D cell cultures for both CaEP as well as ECT with bleomycin. The results suggest a dose-dependent ATP depletion with a wide range of sensitivity among the tested UM cell lines, control groups, and the applied settings in both 2D monolayer cell cultures and 3D tumor spheroid models. The colony formation capacity of the cell lines after two weeks reduced significantly after CaEP only with 0.5 mg/mL and 1.1 mg/mL, whereas the same effect could be achieved with both applied bleomycin concentrations, 1.0 µg/mL and 2.5 µg/mL, for the ECT group. The specific growth rate on day 7 following CaEP was significantly reduced in UM92.1 cell lines with 0.5 and 1.1 mg/mL calcium chloride, while Mel270 showed a similar effect only after administration of 1.1 mg/mL. UM92.1 and Mel270 spheroids exhibited lower adhesion and density after CaEP on day three in comparison to UPM spheroids showing detachment after day 7 following treatment. CaEP and bleomycin electroporation significantly reduce cell viability at similar applied voltage settings. CaEP may be a feasible and inexpensive therapeutic option for the local tumor control with fewer side effects, in comparison to other chemotherapeutic agents, for the treatment of uveal melanoma. The limited effect on normal cells and the surrounding tissue has already been investigated, but further research is necessary to clarify the effect on the surrounding tissue and to facilitate its application in a clinical setting for the eye.
Electrochemotherapy is now in development for treatment of deep-seated tumors, like in bones and internal organs, such as liver. The technology is available with a newly developed electric pulse ...generator and long needle electrodes; however the procedures for the treatment are not standardized yet. In order to describe the treatment procedure, including treatment planning, within the ongoing clinical study, a case of successful treatment of a solitary metastasis in the liver of colorectal cancer is presented. The procedure was performed intraoperatively by inserting long needle electrodes, two in the center of the tumor and four around the tumor into the normal tissue. The insertion of electrodes proved to be feasible and was done according to the treatment plan, prepared by numerical modeling. After intravenous bolus injection of bleomycin the tumor was exposed to electric pulses. The delivery of the electric pulses did not interfere with functioning of the heart, since the pulses were synchronized with electrocardiogram in order to be delivered outside the vulnerable period of the ventricles. Also the post treatment period was uneventful without side effects. Re-operation of the treated metastasis demonstrated feasibility of the reoperation, without secondary effects of electrochemotherapy on normal tissue. Good antitumor effectiveness with complete tumor destruction was confirmed with histological analysis. The patient is disease-free 16 months after the procedure. In conclusion, treatment procedure for electrochemotherapy proved to be a feasible technological approach for treatment of liver metastasis. Due to the absence of the side effects and the first complete destruction of the treated tumor, treatment procedure for electrochemotherapy seems to be a safe method for treatment of liver metastases with good treatment effectiveness even in difficult-to-reach locations.
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