Electrochemotherapy in treatment of tumours.

Aim: Electrochemotherapy is a local drug delivery approach aimed at treatment with palliative intent of cutaneous and subcutaneous tumour nodules of different histologies. Electrochemotherapy, via cell membrane permeabilising electric pulses, potentiates the cytotoxicity of non-permeant or poorly permeant anticancer drugs with high intrinsic cytotoxicity, such as bleomycin or cisplatin, at the site of electric pulse application.

Methods: An overview of preclinical and clinical studies is presented, and the treatment procedure is further critically evaluated.

The effect of the histological properties of tumors on transfection efficiency of electrically assisted gene delivery to solid tumors in mice.

Uniform DNA distribution in tumors is a prerequisite step for high transfection efficiency in solid tumors. To improve the transfection efficiency of electrically assisted gene delivery to solid tumors in vivo, we explored how tumor histological properties affected transfection efficiency. In four different tumor types (B16F1, EAT, SA-1 and LPB), proteoglycan and collagen content was morphometrically analyzed, and cell size and cell density were determined in paraffin-embedded tumor sections under a transmission microscope.

Effective treatment of multiple unresectable skin melanoma metastases by electrochemotherapy.

Multiple unresectable melanoma skin metastases pose a treatment problem, especially in centers where isolated limb perfusion is not available. We report the case of a 59-year-old woman who developed multiple small unresectable cutaneous melanoma metastases on the thigh after her lower limb was amputated. Electrochemotherapy with bleomycin resulted in good local control of the disease, with a complete response of the treated melanoma nodules (224 tumor nodules) after 4 treatment sessions.

Electrogene therapy with p53 of murine sarcomas alone or combined with electrochemotherapy using cisplatin.

The aim of our study was to evaluate feasibility and therapeutic potential of electrogene therapy with p53 alone or combined with electrochemotherapy using cisplatin on two murine sarcomas with different p53 status. Antitumor effectiveness of three consecutive electrogene treatments with p53 was more effective in wild-type LPB tumors than mutated SA-1 tumors, resulting in 21.4% of tumor cures in LPB tumors and 12.

The endothelial cytoskeleton as a target of electroporation-based therapies.

Electroporation-based therapies, such as electrochemotherapy and electrogene therapy, result in the disruption of blood vessel networks in vivo and cause changes in blood flow and vascular permeability. The effects of electroporation on the cytoskeleton of cultured primary endothelial cells and on endothelial monolayer permeability were investigated to elucidate possible mechanisms involved. Human umbilical vein endothelial cells (HUVECs) were electroporated in situ and then immunofluorescence staining for filamentous actin, beta-tubulin, vimentin, and VE-cadherin as well as Western blotting analysis of levels of phosphorylated myosin light chain and cytoskeletal proteins were performed.

Electrically-assisted nucleic acids delivery to tissues in vivo: where do we stand?

Electropulsation (electroporation) is a physical method for delivery of various molecules into the cells in vitro and in vivo. It is an expanding field due to its applicability in cancer therapy, where combined application of electric pulses and chemotherapeutic drugs is used for treatment of cutaneous and subcutaneous nodules of different malignancies. Another application of electropulsation in vivo is electrogene therapy, where after injection of naked plasmid DNA and delivery of electric pulses directly to the tissue the expression of gene of interest can be obtained.

In vivo imaging of tumor growth after electrochemotherapy with cisplatin.

Imaging methods can give both temporal and spatial dimensions to characterize the processes in progression of and/or treatment of specific disease Subcutaneous tumors can be cured after electrochemotherapy (ECT). Growth and reduction of tumors as a result of cytotoxic therapy can be followed by fluorescence video imaging directly on the same animal after treatment. Imaging of tumors should bring more information on the cellular effects of ECT.

Cytotoxicity of different platinum (II) analogues to human tumour cell lines in vitro and murine tumour in vivo alone or combined with electroporation.

Background: The in vitro cytotoxic activity of two new platinum(II) complexes (3P-SK and PtAMP) in comparison with cisplatin (CDDP), oxaliplatin (OXA) and carboplatin (CARBO) was determined in four different human tumour cell lines. The in vivo efficiencies of CDDP and 3P-SK in MCA mammary carcinoma tumours induced in CBA mice were compared.

Materials And Methods: The in vitro cytotoxicity of the platinum (II) complexes was determined by the colorimetric MTT assay.

Sequence and time dependence of transfection efficiency of electrically-assisted gene delivery to tumors in mice.

Electrically-assisted gene delivery is a non-viral gene delivery technique, using application of square wave electric pulses to facilitate uptake of plasmid DNA into the cells. Feasibility and effectiveness of this method in vivo was already demonstrated, elaborating on pulse parameters and plasmid construction. However, there were no studies performed on sequencing and timing of plasmid DNA injection into the tumors and application of electric pulses.

Radiosensitising effect of electrochemotherapy with bleomycin in LPB sarcoma cells and tumors in mice.

Background: Bleomycin is poorly permeant but potent cytotoxic and radiosensitizing drug. The aim of the study was to evaluate whether a physical drug delivery system - electroporation can increase radiosensitising effect of bleomycin in vitro and in vivo.

Methods: LPB sarcoma cells and tumors were treated either with bleomycin, electroporation or ionizing radiation, and combination of these treatments.

Effective treatment of perianal tumors in dogs with electrochemotherapy.

Background: Electrochemotherapy is an antitumor therapy that utilizes locally-delivered, short intense direct current electric pulse to the tumor nodule plus chemotherapy. The aim of the present study was to evaluate the electrochemotherapy treatment of perianal tumors of different sizes in dogs.

Materials And Methods: In 12 dogs, 26 tumor nodules of perianal tumors of different size, and clinically expected to be of different histological type, were treated with electrochemotherapy.

The effect of high frequency electric pulses on muscle contractions and antitumor efficiency in vivo for a potential use in clinical electrochemotherapy.

Muscle contractions present the main source of unpleasant sensations for patients undergoing electrochemotherapy. The contractions are a consequence of high voltage pulse delivery. Relatively low repetition frequency of these pulses (1 Hz) results in separate muscle contractions associated with each single pulse that is delivered.

Successful sphincter-saving treatment of anorectal malignant melanoma with electrochemotherapy, local excision and adjuvant brachytherapy.

Anorectal malignant melanoma is a rare tumor and there is no consensus on whether aggressive or local management is more appropriate. Local sphincter-saving excision has been shown to have a higher recurrence rate than abdominoperineal resection, although there is no long-term survival difference between the two approaches. Therefore, new adjuvant treatment strategies to permit local sphincter-saving excisions are warranted.

Direct visualization of electroporation-assisted in vivo gene delivery to tumors using intravital microscopy - spatial and time dependent distribution.

Background: Electroporation is currently receiving much attention as a way to increase drug and DNA delivery. Recent studies demonstrated the feasibility of electrogene therapy using a range of therapeutic genes for the treatment of experimental tumors. However, the transfection efficiency of electroporation-assisted DNA delivery is still low compared to viral methods and there is a clear need to optimize this approach.

Antitumour effectiveness of hyperthermia is potentiated by local application of electric pulses to LPB tumours in mice.

Background: The aim of our study was to determine whether local application of electric pulses to tumours, which induce transient reduction of tumour perfusion, could potentiate the antitumour effectiveness of hyperthermia.

Materials And Methods: The antitumour effectiveness of local application of electric pulses (1300 V/cm, 100 micros, 1 Hz) and 910 MHz local hyperthermia at 43.5 degrees C, alone or in combination, was determined on LPB tumours in C57Bl/6 mice by measurement of tumour growth delay, changes in tumour perfusion using the Patent blue technique and extent of tumour necrosis.

Electrochemotherapy with cisplatin of cutaneous tumor lesions in breast cancer.

We have evaluated the efficiency of electrochemotherapy with cisplatin on cutaneous tumor lesions of breast cancer and have compared its efficiency with the efficiency of intratumoral (i.t.) administration of cisplatin alone.

EPR oximetry of tumors in vivo in cancer therapy.

The partial oxygen pressure (pO2) in tumors is considered to be one of important factors that affect the response of tumors to different treatment. Therefore, we anticipate that the information about the variation of oxygen concentration in tumors can be used as a guide for individualizing radiotherapy, chemotherapy, and especially the combined therapies. There is thus a need to obtain quantitative data on the effects of different therapies on tumor oxygenation under in vivo conditions.

Effects of electrogenetherapy with p53wt combined with cisplatin on curvival of human tumor cell lines with different p53 status.

The aim of our study was to evaluate electrogenetherapy with p53wt alone or combined with cisplatin on two colorectal (HT-29 and LoVo) and two prostatic (PC-3 and Du145) carcinoma cell lines with different p53 status. In addition, the feasibility of electrogenetherapy with p53wt was tested also in vivo on PC-3 prostatic cancer xenografts. Electrogenetherapy with p53wt was dependent on the p53 status of the cell lines used.

Electroporation of LPB sarcoma cells in vitro and tumors in vivo increases the radiosensitizing effect of cisplatin.

Background: Cisplatin is a cytotoxic drug with radiosensitizing effect. In this study a physical drug delivery system, electroporation, was used to facilitate cisplatin delivery into the cells and tumors with the aim of increasing radiation response.

Materials And Methods: LPB murine sarcoma cells and tumors were treated either by cisplatin, electroporation or ionizing radiation, and combinations of these.

Perturbation of blood flow as a mechanism of anti-tumour action of direct current electrotherapy.

Anti-tumour effects of direct current electrotherapy are attributed to different mechanisms depending on the electrode configuration and on the parameters of electric current. The effects mostly arise from the electrochemical products of electrolysis. Direct toxicity of these products to tumour tissue is, however, not a plausible explanation for the observed tumour growth retardation in the case when the electrodes are placed into healthy tissue surrounding the tumour and not into the tumour itself.

Reduced blood flow and oxygenation in SA-1 tumours after electrochemotherapy with cisplatin.

Electrochemotherapy is an antitumour treatment that utilises locally delivered electric pulses to increase cytotoxicity of chemotherapeutic drugs. Besides increased drug delivery, application of electric pulses affects tumour blood flow. The aim of this study was to determine tumour blood flow modifying effects of electrochemotherapy with cisplatin, its effects on tumour oxygenation and to determine their relation to antitumour effectiveness.

Oxygenation and blood flow in tumors treated with hydralazine: evaluation with a novel luminescence-based fiber-optic sensor.

Two optical methods were used simultaneously to evaluate the effect of a vasoactive drug hydralazine on oxygenation and blood flow in SA-1 tumors in A/J mice. A novel luminescence-based optical sensor (OxyLite instrument, Oxford Optronix, UK) was used to monitor partial pressure of oxygen (pO2) in tumors. Laser Doppler flowmetry was used to assess relative blood perfusion in tumors.

Optimisation of pulse parameters in vitro for in vivo electrochemotherapy.

The aim of our study was to optimise electric pulse parameters for electrochemotherapy by sampling the space of pulse parameter variables using systematic in vitro experiments. For this purpose we defined parameters that describe the effectiveness of different sets of electric pulse parameters in vitro and combined them into an objective function that characterises requirements for successful electrochemotherapy. The objective function values were calculated for all the sets of electric pulse parameters included in in vitro experiments.

Schedule-dependent interaction between vinblastine and cisplatin in Ehrlich ascites tumors in mice.

Information on the in vivo antitumor efficiency of the combination of Vinca alkaloids in animal tumor models, especially vinblastine (VLB) with cisplatin [cis-diamminedichloroplatinum(II); CDDP] is very limited. Therefore, the aim of our study was to explore whether antitumor schedule dependence exists for the combination of CDDP and VLB on i.p.