Electrochemotherapy for colorectal cancer with commonly used chemotherapeutic agents in a mouse model

Pulsed electric fields with calcium ions stimulate oxidative alternations and lipid peroxidation in human non-small cell lung cancer

Pulsed electric fields (PEFs) are commonly used to facilitate the delivery of various molecules, including pharmaceuticals, into living cells. However, the applied protocols still require optimization regarding the conditions of the permeabilization process, i.e., pulse waveform, voltage, duration, and the number of pulses in a burst. This study highlights the importance of electrochemical processes involved in the electropermeabilization process, known as electroporation. This research investigated the effects of electroporation on human non-small cell lung cancer cells (A549) in potassium (SKM) and HEPES-based buffers (SHM) using sub-microsecond and microsecond range pulses. The experiments were performed using 100 ns - 100 μs (0.6-15 kV/cm) bursts with 8 pulses in a sequence. It was shown that depending on the buffer composition, the susceptibility of cells to PEF varies, while calcium enhances the cytotoxic effects of PEF, if high cell membrane permeabilization is triggered. It was also determined that electroporation with calcium ions induces oxidative stress in cells, including lipid peroxidation (LPO), generation of reactive oxygen species (ROS), and neutral lipid droplets. Here, we demonstrated that calcium ions and optimized pulse parameters could potentiate PEF efficacy and oxidative alternations in lung cancer cells. Thus, the anticancer efficacy of PEF in lung cancers in combination with standard cytostatic drugs or calcium ions should be considered, but this issue still requires in-depth detailed studies with in vivo models.

Electrochemotherapy: An Alternative Strategy for Improving Therapy in Drug-Resistant SOLID Tumors

Simple Summary

Chemotherapy is becoming an increasingly difficult antitumor therapy to practice due to the multiple mechanisms of drug resistance. To overcome the problem, it is possible to use alternative techniques, such as electrochemotherapy, which involves the simultaneous administration of the electrical pulse (electroporation) and the treatment with the drug in order to improve the effectiveness of the drug against the tumor. Electroporation has improved the efficacy of some chemotherapeutic agents, such bleomycin, cisplatin, mitomycin C, and 5-fluorouracil. The results of in vitro, veterinary, and clinical oncology studies are promising on various cancers, such as metastatic melanoma. The purpose of this review is to give an update on the state of the art of electrochemotherapy against the main solid tumors in the preclinical, clinical, and veterinary field.

Abstract

Electrochemotherapy (ECT) is one of the innovative strategies to overcome the multi drug resistance (MDR) that often occurs in cancer. Resistance to anticancer drugs results from a variety of factors, such as genetic or epigenetic changes, an up-regulated outflow of drugs, and various cellular and molecular mechanisms. This technology combines the administration of chemotherapy with the application of electrical pulses, with waveforms capable of increasing drug uptake in a non-toxic and well tolerated mechanical system. ECT is used as a first-line adjuvant therapy in veterinary oncology, where it improves the efficacy of many chemotherapeutic agents by increasing their uptake into cancer cells. The chemotherapeutic agents that have been enhanced by this technique are bleomycin, cisplatin, mitomycin C, and 5-fluorouracil. After their use, a better localized control of the neoplasm has been observed. In humans, the use of ECT was initially limited to local palliative therapy for cutaneous metastases of melanoma, but phase I/II studies are currently ongoing for several histotypes of cancer, with promising results. In this review, we described the preclinical and clinical use of ECT on drug-resistant solid tumors, such as head and neck squamous cell carcinoma, breast cancer, gynecological cancer and, finally, colorectal cancer.

Tumor models to assess immune response and tumor-microbiome interactions in colorectal cancer

Despite significant advances over the past 2 decades in preventive screening and therapy aimed at improving patient survival, colorectal cancer (CRC) remains the second most common cause of cancer death in the United States. The average 5-year survival rate of CRC patients with positive regional lymph nodes is only 40%, while less than 5% of patients with distant metastases survive beyond 5 years. There is a critical need to develop novel therapies that can improve overall survival in patients with poor prognoses, particularly since 60% of them are diagnosed at an advanced stage. Pertinently, immune checkpoint blockade therapy has dramatically changed how we treat CRC patients with microsatellite-instable high tumors. Furthermore, accumulating evidence shows that changes in gut microbiota are associated with the regulation of host antitumor immune response and cancer progression. Appropriate animal models are essential to deciphering the complex mechanisms of host antitumor immune response and tumor-gut microbiome metabolic interactions. Here, we discuss various mouse models of colorectal cancer that are developed to address key questions on tumor immune response and tumor-microbiota interactions. These CRC models will also serve as resourceful tools for effective preclinical studies.

New therapeutic strategy: Personalization of pancreatic cancer treatment-irreversible electroporation (IRE), electrochemotherapy (ECT) and calcium electroporation (CaEP) - A pilot preclinical study

In this study, irreversible electroporation (IRE), electrochemotherapy (ECT), and calcium electroporation (CaEP) techniques were investigated as new strategies for human pancreatic cancer. Qualification of the patients, best "therapeutic moment" for each patient, safety, and complications after procedures were examined. In this pilot study were included 13 patients in this study, which were operated on in different pancreatic cancer stages. Patients underwent IRE or ECT with intravenous admission of cisplatin or electroporation with calcium intratumoral administration. The IRE procedure was safe for the patients. Medium overall survival for IRE, IRE + CTH, and IRE + CaCl₂ was respectively: 16, 29.5, and 19 months comparing to 10 months in control chemotherapy (CTH) group. Thus, IRE, ECT, and CaEP can be effective strategies for pancreatic cancer treatment.

Overcoming transporter-mediated multidrug resistance in cancer: failures and achievements of the last decades

Multidrug resistance (MDR) is a complex phenomenon caused by numerous reasons in cancer chemotherapy. It is related to the abnormal tumor metabolism, precisely increased glycolysis and lactic acid production, extracellular acidification, and drug efflux caused by transport proteins. There are few strategies to increase drug delivery into cancer cells. One of them is the inhibition of carbonic anhydrases or certain proton transporters that increase extracellular acidity by proton extrusion from the cells. This prevents weakly basic chemotherapeutic drugs from ionization and increases their penetration through the cancer cell membrane. Another approach is the inhibition of MDR proteins that pump the anticancer agents into the extracellular milieu and decrease their intracellular concentration. Physical methods, such as ultrasound-mediated sonoporation, are being developed, as well. To increase the efficacy of sonoporation, various microbubbles are used. Ultrasound causes microbubble cavitation, i.e., periodical pulsation of the microbubble, and destruction which results in formation of temporary pores in the cellular membrane and increased permeabilization to drug molecules. This review summarizes the main approaches to reverse MDR related to the drug penetration along with its applications in preclinical and clinical studies.

Irreversible electroporation enhances delivery of gemcitabine to pancreatic adenocarcinoma

INTRODUCTION

Irreversible electroporation (IRE) utilizes short, high-voltage pulses to irreversibly permeabilize the cell membrane, resulting in apoptotic cell death. In addition to the irreversible zone, IRE creates a reversible zone that could be utilized for enhanced drug delivery. The hypothesis of this study is that a zone of reversible electroporation exists and allows for increased chemotherapy delivery.

METHODS

Ten immunocompromised mice with orthotopic human pancreatic adenocarcinoma tumors (Panc1) were treated with either IRE between two doses of gemcitabine (15 mg/kg) (ECT) (N = 5) or gemcitabine alone (N = 5). Gemcitabine levels in the serum, liver, and pancreas were analyzed with liquid chromatography/mass spectrometry (LC/MS).

RESULTS

Concentration of gemcitabine within reversibly electroporated pancreatic tissue was higher in mice receiving ECT compared to those receiving gemcitabine alone (13,567 ng/ml vs.4,126 ng/ml; P = 0.0009). Pancreatic gemcitabine levels were 5.52 and 5.96 times higher than liver and serum levels, respectively, in the ECT group compared to 2.85 and 2.53 times higher (P = 0.117, P = 0.058), respectively, in mice receiving gemcitabine alone.

CONCLUSION

IRE can potentially reduce local recurrence by allowing increased drug delivery to the tissue in the reversible electroporation zone. This holds significant potential in augmenting efficacy of gemcitabine in treatment of locally advanced and borderline resectable pancreatic adenocarcinoma. J. Surg. Oncol. 2016;114:181-186. © 2016 Wiley Periodicals, Inc.

Electrochemotherapy as a new approach on pancreatic cancer and on liver metastases

Electrochemotherapy is a local non-thermal treatment for cancer ablation. Currently, many studies and case report have investigated the differences in effectiveness of electrochemotherapy with respect to tumor type, chemotherapeutic drug, and route of drug administration. ESOPE trial validated standard operating procedures [SOP] for ECT using the Cliniporator device and demonstrated that ECT is a simple, highly efficacious, and cost-effective treatment of cutaneous and subcutaneous nodules from different primary tumors for cutaneous or superficial lesions. This review has the purpose to summarize current knowledge about clinical effectiveness of electrochemotherapy and future prospects regarding its use on pancreatic cancer and liver metastasis not only.

In vitro and in vivo experiments on electrochemotherapy for bladder cancer

PURPOSE

Electrochemotherapy is widely performed to treat solid tumors but experience with bladder cancer is limited. We investigated mitomycin C and cisplatin administered with electrochemotherapy for bladder cancer in vitro and in vivo.

MATERIALS AND METHODS

The human bladder cancer cell line SW780 was used. Cells were treated with electroporation, drug alone or electroporation plus increasing concentrations of drug (mitomycin C 0.001 to 2,000 μM or cisplatin 1.56 to 300 μM). Electrochemotherapy parameters were 8 pulses of 1.2 kV/cm for 99 microseconds at 1 Hz. We investigated survival and apoptosis, the latter evaluated by caspase activity. NMRI-Fox1nu nude mice were inoculated subcutaneously and randomized to 1) electrochemotherapy plus NaCl, 2) NaCl alone, 3) electrochemotherapy plus drug or 4) drug alone (mitomycin C 5 mM or cisplatin 250 μM). Tumors were measured 3 times per week. A similar experiment was done to assess necrosis by histology at days 2 and 6.

RESULTS

In vitro mitomycin C cytotoxicity and caspase activity was unaffected by electrochemotherapy (p = 0.9057 and 0.53, respectively). However, electrochemotherapy with cisplatin caused 6.6-fold increased cytotoxicity and higher caspase activity (p <0.0001 and <0.001, respectively). In vivo electrochemotherapy plus mitomycin C resulted in tumor volume reduction (p <0.0005). The survival rate in mice that received electrochemotherapy plus mitomycin C and mitomycin C alone was greater than in controls (p = 0.0004). The tumor response rate was 100% for electrochemotherapy plus mitomycin C, 53% for mitomycin C alone, 14% for electrochemotherapy plus NaCl and 0% for NaCl alone. In vivo electrochemotherapy plus cisplatin was associated with slower tumor growth over other combinations as well as significantly higher survival (p = 0.0005 and 0.0003, respectively). The tumor response rate was 47% for electrochemotherapy plus cisplatin, 0% for cisplatin alone, 0% for electrochemotherapy plus NaCl and 8% for NaCl alone

CONCLUSIONS

In vivo electrochemotherapy with mitomycin C or cisplatin was more effective than chemotherapy alone in a bladder cancer tumor model, opening new perspectives in bladder cancer therapy.

Role of electrochemotherapy in the treatment of metastatic melanoma and other metastatic and primary skin tumors

Electroporation is a novel therapeutic modality that uses pulsed electrical currents to enhance the uptake of drugs, vaccines and genes into cells, and has been used for over 20 years. Electroporation therapy using cytotoxic drugs is called electrochemotherapy. Electrochemotherapy has been studied in vitro, in vivo and in clinical trials. It is potentially useful for treating patients with metastatic tumors, such as melanoma, and even select primary tumors, such as head and neck squamous cell carcinomas and basal cell carcinoma. Various chemotherapeutic agents have been tested with electroporation therapy, but bleomycin and cisplatin are the two most widely used. The biological basis of electroporation therapy is outlined in this review and basic science studies and the limited clinical studies that have involved electrochemotherapy are reviewed. Particular focus is placed on trials involving melanoma, head and neck cancers and other primary and metastatic skin cancers.

Cellular stress induced by photodynamic reaction with CoTPPS and MnTMPyPCl5 in combination with electroporation in human colon adenocarcinoma cell lines (LoVo and LoVoDX)

Two porphyrins, CoTPPS and MnTMPyPCl5, were tested for their photodynamic activity and potential novel use in a therapy of human cancers. We investigated an effect of photodynamic reaction (PDR), electroporation (EP) and their combination (electro-photodynamic reaction [EP-PDR]) on human colon adenocarcinoma cell lines (LoVo and resistant to doxorubicin LoVoDX), human breast adenocarcinoma (wild type MCF-7/WT and resistant to doxorubicin MCF-7/DOX), and human melanoma (Me45). The efficiency of macromolecules transport was examined with cytofluorymetry by assessing the degree of propidium iodide (PI) penetration. Additionally, cellular ultrastructure after EP was evaluated. We determined cyto- and photo-cytotoxic effect on the cells viability (MTT assay) after standard PDR and PDR combined with EP. Intracellular distribution and mitochondrial colocalization of both porphyrins was also performed. The experiments proved that both complexes exhibit desirable photodynamic properties on LoVo LoVoDX cells, and EP effectively supports photodynamic method in this type of cancer. The application of EP provided shorter time of incubation (only 10 min) and enhanced effect of applied therapy. The porphyrins did not affect the MCF-7 and Me45 cell lines.

Involvement of bone marrow-derived stromal cells in gastrointestinal cancer development and metastasis

BACKGROUND

The involvement of bone marrow (BM) in tumor-stroma reactions or tumor development has not been examined in a cancer allograft, which has otherwise been appropriate for assessing therapeutic modalities. We investigated the fate of BM-derived cells in colon cancer allografts and liver metastases in mice.

METHODS

C57BL/6 mice were irradiated and rescued by BM transplantation from green fluorescent protein (GFP)-transgenic mice. MC38 colon cancer cells were stably transfected with the pDsRed gene in order to identify tumor cells by fluorescence. These were inoculated into the mice to generate subcutaneous allografted tumors or liver metastases. The tumors were observed under confocal microscopy and fluorescent immunohistochemistry to determine the fate of tumor versus BM-derived cells.

RESULTS

GFP-positive (GFP(+)) cells were consistently identified as vimentin(+), alpha-smooth muscle actin (alphaSMA)(+), spindle-shaped stromal cells in both the subcutaneous tumors and the liver metastases. GFP(+) cells of leukocyte lineage also infiltrated the tumors. Neither GFP(+) CD31(+) endothelial cells nor GFP(+) DsRed(+) cells were detected in the tumor.

CONCLUSIONS

BM-derived cells frequently and consistently infiltrated the tumor allografts and metastases as interstitial cells and leukocytes. Cells derived from the fusion of BM cells and tumor cells were not observed. This model may be appropriate for the clarification of the effects of anticancer therapies and the study of BM-derived cells in tumor-host interactions.

Overview of drug delivery and alternative methods to electroporation

This chapter provides an overview of the application of electroporation to areas other than gene delivery. These areas include the delivery of drugs and vaccines to tissues and tumors as well as into and through the skin. Achievements and limitations of electroporation in these areas are presented. Alternative physical methods for gene and drug delivery besides electroporation are described. The advantages and drawbacks of electroporation, compared with these methods, are also discussed.

Effects and possible anti-tumor immunity of electrochemotherapy with bleomycin on human colon cancer xenografts in nude mice

AIM: To evaluate the anti-tumor effects and possible involvement of anti-tumor immunity of electrochemotherapy (ECT) employing electroporation and bleomycin in human colon cancer xenografts in nude mice, and to establish the experimental basis for clinical application of ECT.

METHODS: Forty nude mice, inoculated subcutaneously human colon cancer cell line LoVo for 3 wk, were allocated randomly into four groups: B+E+ (ECT), B+E- (administration of bleomycin alone), B-E+ (administration of electric pulses alone), and B-E- (no treatment). Tumor volumes were measured daily. The animals were killed on the 7^th d, the weights of xenografts were measured, and histologies of tumors were evaluated. Cytotoxicity of spleen natural killer (NK) and lymphokine-activated killer (LAK) cells was then assessed by lactic dehydrogenase release assay.

RESULTS: The mean tumor volume of group B+E+ was statistically different from the other three groups after the treatment (F = 36.80, P<0.01). There was one case of complete response, seven cases of partial response (PR) in group B+E+, one case of PR in group B+E- and group B-E+ respectively, and no response was observed in group B-E-. The difference of response between group B+E+ and the other three groups was statistically significant (χ² = 25.67, P<0.01). Histologically, extensive necrosis of tumor cells with considerable vascular damage and inflammatory cells infiltration were observed in group B+E+. There was no statistical difference between the cytotoxicity of NK and LAK cells in the four treatment groups.

CONCLUSION: ECT significantly enhances the chemosensitivity and effects of chemotherapy in human colon cancer xenografts in nude mice, and could be a kind of novel treatment modality for human colon cancer. The generation of T-cell-dependent, tumor-specific immunity might be involved in the process of ECT.

Low electric field enhanced chemotherapy can cure mice with CT-26 colon carcinoma and induce anti-tumour immunity

Low electric field cancer treatment-enhanced chemotherapy (LEFCT-EC) is a new anticancer treatment which utilizes a combination of chemotherapeutic agents and a low electric field. We investigated the antitumour effectiveness of this technique in a model of murine colon carcinoma (CT-26). The low electric field was applied to approximately 65 mm3 intracutaneous tumours after intratumoral injection of 5FU, bleomycin or BCNU. We observed significant tumour size reduction and a prolongation of survival time. The complete cure of a significant fraction of animals treated by LEFCT-EC with 5FU (33%), bleomycin (51%) or BCNU (83%) was observed. Mice cured by LEFCT-EC developed resistance to a tumour challenge and their splenocytes had antitumour activity in vivo. Our results suggest that LEFCT-EC is an effective method for treatment of solid tumours.