Mild hyperthermia prior to electroporation increases transfection efficiency in HCT 116, HeLa S3 and SGC 7901 cells

Effect of Experimental Electrical and Biological Parameters on Gene Transfer by Electroporation: A Systematic Review and Meta-Analysis

The exact mechanisms of nucleic acid (NA) delivery with gene electrotransfer (GET) are still unknown, which represents a limitation for its broader use. Further, not knowing the effects that different experimental electrical and biological parameters have on GET additionally hinders GET optimization, resulting in the majority of research being performed using a trial-and-error approach. To explore the current state of knowledge, we conducted a systematic literature review of GET papers in in vitro conditions and performed meta-analyses of the reported GET efficiency. For now, there is no universal GET strategy that would be appropriate for all experimental aims. Apart from the availability of the required electroporation device and electrodes, the choice of an optimal GET approach depends on parameters such as the electroporation medium; type and origin of cells; and the size, concentration, promoter, and type of the NA to be transfected. Equally important are appropriate controls and the measurement or evaluation of the output pulses to allow a fair and unbiased evaluation of the experimental results. Since many experimental electrical and biological parameters can affect GET, it is important that all used parameters are adequately reported to enable the comparison of results, as well as potentially faster and more efficient experiment planning and optimization.

Experimental and Numerical Investigation of Parameters Affecting High-frequency Irreversible Electroporation for Prostate Cancer Ablation

While the primary goal of focal therapy for prostate cancer (PCa) is conserving patient quality of life by reducing oncological burden, available modalities use thermal energy or whole-gland radiation which can damage critical neurovascular structures within the prostate and increase risk of genitourinary dysfunction. High-frequency irreversible electroporation (H-FIRE) is a promising alternative ablation modality that utilizes bursts of pulsed electric fields (PEFs) to destroy aberrant cells via targeted membrane damage. Due to its non-thermal mechanism, H-FIRE offers several advantages over state-of-the-art treatments, but waveforms have not been optimized for treatment of PCa. In this study, we characterize lethal electric field thresholds (EFTs) for H-FIRE waveforms with three different pulse widths as well as three interpulse delays in vitro and compare them to conventional IRE. Experiments were performed in non-neoplastic and malignant prostate cells to determine the effect of waveforms on both targeted (malignant) and adjacent (non-neoplastic) tissue. A numerical modeling approach was developed to estimate the clinical effects of each waveform including extent of non-thermal ablation, undesired thermal damage, and nerve excitation. Our findings indicate that H-FIRE waveforms with pulse durations of 5 and 10 µs provide large ablations comparable to IRE with tolerable levels of thermal damage and minimized muscle contractions. Lower duration (2 µs) H-FIRE waveforms exhibit the least amount of muscle contractions but require increased voltages which may be accompanied by unwanted thermal damage.

Therapeutic effect of the treatment for colorectal cancer with adenoviral vectors mediated estrogen receptor β gene therapy combined with thermotherapy

INTRODUCTION

Our preliminary study on repressing colorectal tumors by recombinant adenoviruses (Ads) delivering the human ERβ gene (Ad-ERβ) has achieved positive result.

METHODS

In this study, hydrophobic fluorescent dyes ICG-Der-01 was entrapped into the N-succinyl-N'-octyl chitosan (SOC) micelles to form the near infrared absorbing dyes SOC-ICG-Der-01 and SOC-ICG-Der-01 mediated near infrared laser (SOC-ICG-Der-01/NIR) thermotherapy was combined with Ad-ERβ gene therapy to regress colon cancer in vivo.

RESULTS

Firstly, the antitumor efficacies of SOC-ICG-Der-01/NIR thermotherapy were investigated on S180 ascites tumor-bearing mice. Results indicated that, the average tumor volume of SOC-ICG-Der-01/NIR group was the smallest among the three treatment groups. Then, thermotherapy with SOC-ICG-Der-01/NIR combined with Ad-ERβ gene therapy to treat HCT-116 colon cancer xenograft model was investigated. Further results demonstrated that, SOC-ICG-Der-01/NIR thermotherapy showed the significantly inhibitory efficiency compared with control group and Ad-ERβ enhanced the therapeutic effect of SOC-ICG-Der-01/NIR.

CONCLUSION

These findings demonstrated that combined administration of Ad-ERβ with SOC-ICG-Der-01/NIR thermotherapy represents a promising colon cancer therapeutic strategy.