Effects of Cisplatin Electrochemotherapy on Human Neuroblastoma Cells

The estimation of pore size distribution of electroporated MCF-7 cell membrane

The size of the pores created by external electrical pulses is important for molecule delivery into the cell. The size of pores and their distribution on the cell membrane determine the efficiency of molecule transport into the cell. There are very few studies visualizing the presence of electropores. In this study, we aimed to investigate the size distribution of electropores that were created by high intensity and short duration electrical pulses on MCF-7 cell membrane. Scanning Electron Microscopy (SEM) was used to visualize and characterize the membrane pores created by the external electric field. Structural changes on the surface of the electroporated cell membrane was observed by Atomic Force Microscopy (AFM). The size distribution of pore sizes was obtained by measuring the radius of 500 electropores. SEM imaging showed non-uniform patterning. The average radius of the electropores was 12 nm, 51.60% of pores were distributed within the range of 5 to 10 nm, and 81% of pores had radius below 15 nm. These results showed that microsecond (µs) high intensity electrical pulses cause the creation of heterogeneous nanopores on the cell membrane.

Anticancer activity of methotrexate in electrochemotherapy and electrochemotherapy plus ionizing radiation treatments in human breast cancer cells

Traditional cancer treatments, such as chemotherapy and radiotherapy have several limitations. Therefore, their performance must be enhanced with combined methods. The purpose of this study is to investigate both the efficacy of electroporation (EP) on the activity of methotrexate (MTX) and the combined treatment of electrochemotherapy (ECT) + ionizing radiation (IR) in MCF-7 cancer cells. Different treatment techniques, such as EP, MTX, MTX + EP (ECT), 140 kV X-ray alone (IR_140kV), 500 kV X-ray alone (IR_500kV), ECT + IR_140kV and ECT + IR_500kV, were applied to cancer cells. Eight electric pulse trains with square wave (800 V/cm, 100 µs and 1 Hz) were used in EP and ECT applications. The MTT assay was used to assess the efficacy of the therapies used. When the EP, MTX, ECT, IR_140kV, and IR_500kV treatment groups were compared to the control group, there was a significant reduction in MCF-7 cancer cells viability (p < 0.05). ECT was the most effective of these treatments, decreasing viability of cancer cells to 58.78%. The ECT + IR_140kV and ECT + IR_500kV groups were compared to the ECT group to examine the impact of X-ray radiation on ECT treatment. When compared to the ECT alone group, both groups that exposed to X-rays after ECT had a significant decrease in cell viability (p < 0.05). Furthermore, viability of MCF-7 cells reduced to 46.38% in the ECT + IR_140kV group and 35.89% in the ECT + IR_500kV group. In conclusion, the study shows that the cytotoxicity of MTX is significantly increased in ECT treatment compared to standard chemotherapy (p < 0.05). In addition, ECT + IR combined therapy application is much more effective than MTX or ECT treatments alone.

Synthesis, characterization, antiproliferative of pyrimidine based ligand and its Ni(II) and Pd(II) complexes and effectiveness of electroporation

In the study, a new Schiff base (ligand) was obtained using 4-aminopyrimidine-2(1H)-one, the starting material, and 2,3,4-trimethoxy benzaldehyde. Ni(II) and Pd(II) complexes were obtained from the reaction of the ligand and NiCl₂·6H₂O, PdCl₂(CH₃CN)₂ (1:1 ratio). These compounds were characterized using the elemental and mass analysis, ¹H, ¹³C-NMR, FT-IR, UV-Vis, magnetic susceptibility, thermal analysis, and the X-ray diffraction analyses. The antiproliferative activities of the synthesized ligand, Ni(II) and Pd(II) complexes were identified on the HepG2 (human liver cancer cells) cell line and their biocompatibility was tested on the L-929 (fibroblast cells) cell line by the MTT analysis method. Furthermore, the effects of electroporation (EP) on the cytotoxic activities of synthesized compounds were investigated in HepG2 cancer cells. According to the MTT findings of the study, the ligand did not exhibit an antiproliferative activity while its Ni(II) and Pd(II) complexes exhibited an antiproliferative activity. Moreover, it was observed that the antiproliferative activity of the Pd(II) complex was stronger than that of the Ni(II) complex. The combined application of EP + compounds is much more effective than the usage of the compounds alone in the treatment of HepG2 cancer cells. The EP increased the cytotoxicity of the Ni(II) and Pd(II) complexes by 1.66, and 2.54 times, respectively. It was concluded that Ni(II) and Pd(II) complexes may contribute as potential anti-cancer agents for the treatment of hepatocellular carcinoma and yield promising results in the case of being used in ECT.Communicated by Ramaswamy H. Sarma.

Implantable Drug Reservoir Devices for Inner Ear Delivery of Pharmacotherapeutics

Objective

Cisplatin is a platinum-based chemotherapeutic drug that secondarily induces toxicity in inner ear sensory epithelia, contributing to auditory and vestibular dysfunction. We describe the creation of a drug reservoir device (DRD) to combat this ototoxicity for the duration of chemotherapy. As ototoxic side effects of chemotherapy may limit an oncologist’s ability to prescribe first-line agents such as cisplatin, mitigating such devastating effects through prolonged topical therapy would be tremendously valuable.

Study Design

We investigated (1) the ability of an electrospun polylactic acid DRD to provide prolonged delivery of the posited otoprotectant metformin and (2) the development of an in vitro model utilizing Sh-Sy5y human neuroblastoma cells to assess the efficacy of metformin in reducing cisplatin-induced toxicity.

Setting

Neurophysiology laboratory.

Methods

Basic science experiments were performed to assess DRD properties and metformin’s effects on cisplatin toxicity in culture.

Results

We found that DRDs with increasing polylactic acid concentrations exhibited metformin release for up to 8 weeks. In modeling elution across the round window in vitro, continued elution of metformin was observed for at least 6 weeks, as quantified by spectrophotometry. Unfortunately, metformin did not exhibit protective efficacy in this model using Sh-Sy5y cells.

Conclusion

While metformin was not found to be protective in Sh-Sy5y cells, these results suggest that an electrospun DRD can provide a tailorable drug delivery system providing medication for the duration of chemotherapy treatment. This represents a novel drug delivery system and efficacy screening assay with broad clinical applications in personalized delivery of inner ear therapies.

Recent Advances in Electrochemotherapy

Electrochemotherapy is gaining recognition as an effective local therapy that uses systemically or intratumorally injected bleomycin or cisplatin with electroporation as a delivery system that brings drugs into the cells to exert their cytotoxic effects. Preclinical work is still ongoing, testing new drugs, seeking the best treatment combination with other treatment modalities, and exploring new sets of pulses for effective tissue electroporation. The applications of electrochemotherapy are being fully exploited in veterinary oncology, where electrochemotherapy, because of its simple execution, has a relatively good cost-benefit ratio and is used in the treatment of cutaneous tumors. In human oncology, electrochemotherapy is fully recognized as a local therapy for cutaneous tumors and metastases. Its effectiveness is being explored in combination with immunomodulatory drugs. However, the development of electrochemotherapy is directed into the treatment of deep-seated tumors with a percutaneous approach. Because of the vast number of reports, this review discusses the articles published in the past 5 years.

Proteomic Signature of Neuroblastoma Cells UKF-NB-4 Reveals Key Role of Lysosomal Sequestration and the Proteasome Complex in Acquiring Chemoresistance to Cisplatin

Cisplatin (CDDP) is a widely used agent in the treatment of neuroblastoma. Unfortunately, the development of acquired chemoresistance limits its clinical use. To gain a detailed understanding of the mechanisms underlying the development of such chemoresistance, we comparatively analyzed established cisplatin-resistant neuroblastoma cell line (UKF-NB-4^CDDP) and its sensitive counterpart (UKF-NB-4). First, using viability screenings, we confirmed the decreased sensitivity of tested cells to cisplatin and identified a cross-resistance to carboplatin and oxaliplatin. Then, the proteomic signatures were analyzed using nano liquid chromatography with tandem mass spectrometry. Among the proteins responsible for UKF-NB-4^CDDP chemoresistance, ion channels transport family proteins, ATP-binding cassette superfamily proteins (ATP = adenosine triphosphate), solute carrier-mediated trans-membrane transporters, proteasome complex subunits, and V-ATPases were identified. Moreover, we detected markedly higher proteasome activity in UKF-NB-4^CDDP cells and a remarkable lysosomal enrichment that can be inhibited by bafilomycin A to sensitize UKF-NB-4^CDDP to CDDP. Our results indicate that lysosomal sequestration and proteasome activity may be one of the key mechanisms responsible for intrinsic chemoresistance of neuroblastoma to CDDP.