Electroporation enhances cell death in 3D scaffold-based MDA-MB-231 cells treated with metformin.

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer lacks estrogen, progesterone, and HER2 receptors and hence, is therapeutically challenging. Towards this, we studied an alternate therapy by repurposing metformin (FDA-approved type-2 diabetic drug with anticancer properties) in a 3D-scaffold culture, with electrical pulses. 3D cell culture was used to simulate the tumor microenvironment more closely and MDA-MB-231, human TNBC cells, treated with both 5 mM metformin (Met) and 8 electrical pulses at 2500 V/cm, 10 µs (EP1) and 800 V/cm, 100 µs (EP2) at 1 Hz were studied in 3D and 2D. They were characterized using cell viability, reactive oxygen species (ROS), glucose uptake, and lactate production assays at 24 h. Cell viability, as low as 20 % was obtained with EP1 + 5 mM Met. They exhibited 1.65-fold lower cell viability than 2D with EP1 + 5 mM Met. ROS levels indicated a 2-fold increase in oxidative stress for EP1 + 5 mM Met, while the glucose uptake was limited to only 9 %. No significant change in the lactate production indicated glycolytic arrest and a non-conducive environment for MDA-MB-231 growth. Our results indicate that 3D cell culture, with a more realistic tumor environment that enhances cell death using metformin and electrical pulses could be a promising approach for TNBC therapeutic intervention studies.

Efficacy of metformin and electrical pulses in breast cancer MDA-MB-231 cells.

Aim: Triple-negative breast cancer (TNBC) is a very aggressive subset of breast cancer, with limited treatment options, due to the lack of three commonly targeted receptors, which merits the need for novel treatments for TNBC. Towards this need, the use of metformin (Met), the most widely used type-2 diabetes drug worldwide, was explored as a repurposed anticancer agent. Cancer being a metabolic disease, the modulation of two crucial metabolites, glucose, and reactive oxygen species (ROS), is studied in MDA-MB-231 TNBC cells, using Met in the presence of electrical pulses (EP) to enhance the drug efficacy. Methods: MDA-MB-231, human TNBC cells were treated with Met in the presence of EP, with various concentrations Met of 1 mmol/L, 2.5 mmol/L, 5 mmol/L, and 10 mmol/L. EP of 500 V/cm, 800 V/cm, and 1,000 V/cm (with a pulse width of 100 µs at 1 s intervals) were applied to TNBC and the impact of these two treatments was studied. Various assays, including cell viability, microscopic inspection, glucose, ROS, and wound healing assay, were performed to characterize the response of the cells to the combination treatment. Results: Combining 1,000 V/cm with 5 mmol/L Met yielded cell viability as low as 42.6% at 24 h. The glucose level was reduced by 5.60-fold and the ROS levels were increased by 9.56-fold compared to the control, leading to apoptotic cell death. Conclusions: The results indicate the enhanced anticancer effect of Met in the presence of electric pulses. The cell growth is inhibited by suppressing glucose levels and elevated ROS. This shows a synergistic interplay between electroporation, Met, glucose, and ROS metabolic alterations. The results show promises for combinational therapy in TNBC patients.

Efficacy of electrical pulse mediated tomato lipophilic extract on human breast cancer cell.

Aim: The purpose of this research is to study the effect of electrical pulse mediated tomato lipophilic extract (TLE) on human breast cancer MCF-7 and non-tumorigenic MCF-10A cells. Materials and Methods: MCF-7 and MCF-10A cells were treated with 50 µg/mL TLE and eight 100 µs electric pulses of different electric field intensities (800, 1000, and 1200 V/cm), and the viability was studied using real time MT assay at 24 h of treatment. In addition, we studied cell viability of both the cells at 0 h using trypan blue assay and the ability to form colonies of both cells using colony forming unit (CFU) assay for all the treatments. We also imaged the cells at 24 h using microscope. Results: With 50 µg/mL TLE, the cell viability of MCF-7 and MCF-10A was same (84%). When the same concentration of TLE is combined with eight electrical pulses of 1200 V/cm, the cell viability of MCF-7 and MCF-10A was 2% and 87%, respectively. These results indicate that the effect of electrical pulses mediated TLE was higher on cancerous MCF-7 cells when compared to non-cancerous MCF-10A cells. Conclusion: The combination of electrical pulses with TLE is an effective strategy to selectively target cancer cells in the body.

Enhancement of reactive oxygen species production in triple negative breast cancer cells treated with electric pulses and resveratrol.

Aim: Triple negative breast cancer (TNBC) is difficult to treat since it lacks all the three most commonly targeted hormone receptors. Patients afflicted with TNBC are treated with platinum core chemotherapeutics, such as cisplatin. Despite the initial effective anticancer effects of cisplatin, TNBC attenuates its effect and develops resistance eventually, which results in tumor reoccurrence. Hence, there is a critical demand for effective, alternative, and natural ways to treat TNBC. Towards this, a promising technique for inhibiting TNBC cell proliferation involves promoting the production of reactive oxygen species (ROS), which triggers pro-apoptotic caspases 9 and 3. Resveratrol (RESV), an active bio compound found in naturally available fruits, such as grapes, is utilized in this research for that. In addition, electrochemotherapy (ECT), which involves the application of electrical pulses (EP), was utilized to enhance the uptake of RESV. Methods: MDA-MB-231, human TNBC cells were treated with/out RESV, and eight 600-1,000 V/cm, 100 µs pulses at 1 Hz. The cells were characterized by using various assays, including viability assay, and ROS assay. Results: A TNBC cell viability of as low as 20% was obtained at 24 h (it was 13% at 60 h), demonstrating the potential of this novel treatment. ROS production was the highest in the combination of EP at 1,000 V/cm along with RESV at 100 µmol/L. Conclusions: Results indicate that RESV has the potential as an anti-TNBC agent and that EP + RESV can significantly enhance the cell death to reduce MDA-MB-231 cell viability by increasing ROS production and triggering apoptosis.

High-throughput, Label-free Proteomics Identifies Salient Proteins and Genes in MDA-MB-231 Cells Treated with Natural Neem-based Electrochemotherapy.

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.

Cisplatin-based Electrochemotherapy Significantly Downregulates Key Heat Shock Proteins in MDA-MB-231-Human Triple-Negative Breast Cancer Cells.

Heat shock proteins (HSPs) are available and/or induced for the survival of all organisms, including eukaryotic, prokaryotic, and plants, from higher temperature stresses. They are the chaperone proteins that protect all cells against heat, as the name implies. In addition to thermal stress, they also protect them from chemical, physical, and other stresses, including exposure to oxidative stress, nutritional deficiencies, ultraviolet radiation, ethanol, viral infection, ischemia-reperfusion injury, and cancer-related stresses. They are classified based on their molecular weights in kDa, such as HSP90 and HSP70. In our label-free, high-throughput, quantitative LC-MS/MS-based proteomic studies of MDA-MB-231, human, triple-negative breast cancer cells, treated with electrical pulses (EP) and cisplatin (CsP), we identified a number of HSPs, such as HSP90AA1, and others to be significantly downregulated in EP + CsP, compared to CsP alone. This indicates that cells will undergo apoptotic cell death and hence could cause effective cancer cure/treatment. Considering that over 2 million new cases and over 600,000 deaths in 2020, of which ~ 15% are TNBC, heat shock proteins could be the untapped resources, available for the next biomarkers and/or inhibitors for new/additional therapies.

Enhanced Antiproliferation Potency of Electrical Pulse-Mediated Metformin and Cisplatin Combination Therapy on MDA-MB-231 Cells.

We investigated the combined potency of metformin and cisplatin on the MDA-MB-231, triple-negative breast cancer (TNBC) cells with the application of electrical pulses. There are no targeted therapies for this subset of breast cancer because of the absence of specific biomarkers. Cytotoxic chemotherapy is the mainstream mode of treatment for TNBC, and cisplatin is the most commonly used chemotherapeutic drug. While there is a good response initially, TNBC cells develop drug resistance eventually. Thus, there is a need for alternate therapies. Toward this, we studied the antiproliferation characteristics of electrical pulse-mediated combination therapy using metformin, the commonly used Type-2 diabetes drug, along with cisplatin. We used metformin, as it has various anticancer properties caused by repressing energy pathways in a cancer cell. Application of 8 pulses of 1000 V/cm, 100 µs, at 1 Hz frequency, enhanced the drug uptake leading to cell viability as low as 25.86% at 30 µM cisplatin and 5 mM metformin in a 24 h study. Also, the same studies were conducted on MCF10A, a non-cancerous human epithelial cell. It aided in comparing the result for both MDA-MB-231 and MCF10A cell lines while establishing a better understanding of the experimental outcomes. Overall, the various experimental results from colony-forming assay, reactive oxidative analysis, and the intracellular glucose metabolic assay indicate the possibility of the electrical pulses-based cisplatin and metformin drug combination as a potential alternative to TNBC treatment.

Electrochemotherapy Modulates Mammary Tumor Growth in Rats on a Western Diet Supplemented with Curcumin.

In the US, every 12 min, six women are diagnosed with breast cancer and one dies. This highlights a critical need for developing alternate therapies using natural compounds, which are cost effective and with less side effects. Curcumin, the yellow pigment of turmeric has been found to suppress initiation, progression, and metastasis of a variety of tumors. Multiple clinical trials highlight the efficacy of curcumin in treating breast cancer and other diseases. Our in vitro studies have demonstrated that the electrical pulse (EP) application can further enhance the effectiveness of curcumin against breast cancer cells in a therapy called electrochemotherapy (ECT). In a direct extension of these results, we studied the effect of ECT coupled with intratumoral curcumin administration (EP+Cur) on N-methyl-N-nitrosourea (MNU) induced mammary tumors in female Sprague Dawley rats. Beginning at the weaning and throughout the study, rats were fed either western diet (West) or western diet, supplemented with 1% curcumin (W+Cur). Our results showed that EP+Cur treatment led to a reduced growth rate in rats fed with W+Cur diet compared to West diet (57.14% vs. 16.67% in West diet). These results provide a foundation for further studies towards utilizing it in clinical practice.

High-throughput, Label-Free Quantitative Proteomic Studies of the Anticancer Effects of Electrical Pulses with Turmeric Silver Nanoparticles: an in vitro Model Study.

Triple negative breast cancer (TNBC) represents 15-20% of the over one million new breast cancer cases occurring each year. TNBC is an aggressive cancer phenotype, with low 5-year survival rates, high 3-year recurrence rates, and increased risk of metastasis. A lack of three commonly exploited hormone receptors renders TNBC resistant to endocrine therapies and lends to its critical absence of viable therapeutic targets. This necessitates the development of alternate and effective novel therapeutic strategies for TNBC. Towards this, our current work seeks to develop the technique of Electrical pulse (EP)-mediated Turmeric silver nanoparticles (TurNP) therapy, known as Electrochemotherapy (ECT), to effectively target TNBC cells. This technique involves the efficient delivery of natural bioactive molecules with anti-cancer effects via a biophysical means. In these experiments, the bioactive molecules are turmeric, a dried rhizome of Curcuma longa that has been used for centuries, both as a dietary supplement and as a medicine in Ayurveda (science of life) in the Indian subcontinent and in traditional Chinese medicine. Our results reveal the combined effect of TurNP + EP treatment in reducing MDA-MB-231 cell viability to as low as 9% at 12 h. Showing biological selectivity, this combination treatment has a substantially lower effect on non-tumorigenic mammary epithelial MCF10A cells (67% viability). To gain mechanistic insights into the actions of TurNP-based ECT treatment, we performed high-throughput, label-free quantitative proteomics studies. Proteomics results indicate that TurNP + EP treatment significantly influenced expression of a diverse list of proteins, including receptors, transcription factors, structural proteins, kinases, and metabolic enzymes. This include the downregulation of 25 proteins in PI3K-Akt signaling pathway (such as GRB2, EGFR, EPHA2, GNB1, GNB2, 14-3-3 family, and Integrin family proteins), and 12 proteins (AKR1A1, ALDOA, ALDOC, PGK1, PGM1, PGAM1, ENO1, ENO2, GAPDH, TPI1, LDHA, and LDHB) in the glycolytic pathway with concomitant reduction in metabolite levels (glucose uptake, and intracellular- lactate, glutamine, and glutamate). Compared to TurNP alone, TurNP + EP treatment upregulated 66 endoplasmic reticulum and 193 mitochondrial proteins, enhancing several processes and pathways, including Pyruvate Metabolism, Tricarboxylic acid (TCA) cycle, and Oxidative Phosphorylation (OXPHOS), which redirected the TNBC metabolism to mitochondria. This switch in the metabolism caused excessive production of H2O2 reactive oxygen species (ROS) to inflict cell death in MDA-MB-231 cells, demonstrating the potency of this treatment.

Effective electrochemotherapy with curcumin in MDA-MB-231-human, triple negative breast cancer cells: A global proteomics study.

Curcumin (Cur), the yellow pigment of well-known turmeric (Curcuma longa L.) is effective in multiple cancers including triple negative breast cancer (TNBC). In combination with electrical pulses (EP), enhanced effects of curcumin (Cur + EP) are observed in TNBC cells. To gain insights into the mechanisms of enhanced anticancer effects of Cur + EP, we studied the proteins involved in the anticancer activity of Cur + EP in MDA-MB-231, human TNBC cells using high-throughput global proteomics. A curcumin dose of 50 µM was applied with eight, 1200 V/cm, 100 µs pulses, the most commonly used electrochemotherapy (ECT) parameter in clinics. Results show that the Cur + EP treatment reduced the clonogenic ability in MDA-MB-231 cells, with the induction of apoptosis. Proteomic analysis identified a total of 1456 proteins, of which 453 proteins were differentially regulated, including kinases, heat shock proteins, transcription factors, structural proteins, and metabolic enzymes. Eight key glycolysis proteins (ALDOA, ENO2, LDHA, LDHB, PFKP, PGM1, PGAM1 and PGK1) were downregulated in Cur + EP from Cur. There was a switch in the metabolism with upregulation of 10 oxidative phosphorylation pathway proteins and 8 tricarboxylic acid (TCA) cycle proteins in the Cur + EP sample, compared to curcumin. These results provide novel systematic insights into the mechanisms of ECT with curcumin.

Author Correction: Quantitative proteomic analysis of enhanced cellular effects of electrochemotherapy with Cisplatin in triple-negative breast cancer cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Quantitative proteomic analysis of enhanced cellular effects of electrochemotherapy with Cisplatin in triple-negative breast cancer cells.

Due to the lack of the three main receptors, triple negative breast cancer (TNBC) is refractive to standard chemotherapy. Hence, alternate therapies are needed. TNBCs utilize glycolysis, which heightens their growth, proliferation, invasiveness, chemotherapeutic resistance and poor therapeutic response. This calls for novel therapeutic strategies to target these metabolic vulnerabilities present in TNBC. Electroporation-mediated chemotherapy, known as electrochemotherapy (ECT) is gaining momentum as an attractive alternative. However, its molecular mechanisms need better understanding. Towards this, label-free quantitative proteomics is utilized to gain insight into the anticancer mechanisms of ECT using electrical pulses (EP) and Cisplatin (CsP) on MDA-MB-231, human TNBC cells. The results indicate that EP + CsP significantly downregulated 14 key glycolysis proteins (including ENO1, LDHA, LDHB, ACSS2, ALDOA, and PGK1), compared to CsP alone. EP + CsP caused a switch in the metabolism with upregulation of 34 oxidative phosphorylation pathway proteins and 18 tricarboxylic acid (TCA) cycle proteins compared to CsP alone, accompanied by the upregulation of proteins linked to several metabolic reactions, which produce TCA cycle intermediates. Moreover, EP + CsP promoted multiple pathways to cause 1.3-fold increase in the reactive oxygen species concentration and induced apoptosis. The proteomics results correlate well with cell viability, western blot, and qPCR data. While some effects were similar for EP, more comprehensive and long-lasting effects were observed for EP + CsP, which demonstrate the potential of EP + CsP against TNBC cells.

Fabrication and characterization of implantable flushable electrodes for electric field-mediated drug delivery in a brain tissue-mimic agarose gel.

Every forty minutes, one person dies in the USA due to glioblastoma multiforme; a deadly form of brain cancer with an average five-year survival rate less than 3%. The current standard of care for treatment involves surgical resection of the accessible tumor followed by radiation therapy and concomitant chemotherapy. Despite their potency, delivering chemotherapeutic agents to the brain is limited by the highly selective blood-brain barrier, which prevents molecules >500 Da from reaching the brain. Other techniques, such as convection-enhanced delivery, controlled release by drug-loaded wafers or intracerebroventricular infusion have limited clinical utility due to unpredictable targeting and volume of drug distribution. We introduce a novel drug delivery technique that can use direct current electric fields to deliver charged chemotherapeutics to the site of brain parenchyma after tumor resection. We fabricate and characterize an implantable drug delivery system using flushable electrodes to deliver the charged chemotherapeutic or doxorubicin (+1) in a brain tissue-mimic agarose gel (0.2% w/v) model by electrophoresis. The optimized capillary-embedded electrode system exhibited a sustained movement of charged doxorubicin through nearly 3.5 mm in four hours, a distance for achieving effective intratumoral concentrations.

Gelidiella acerosa inhibits lung cancer proliferation.

BACKGROUND: Lung adenocarcinoma is the most common subtype of Non small cell lung cancer in which the PI3K/Akt cascade is frequently deregulated. The ubiquitous expression of the PI3K and the frequent inactivation of PTEN accounts for the prolonged survival, evasion of apoptosis and metastasis in cancer. This has led to the development of PI3K inhibitors in the treatment of cancer. Synthetic PI3K inhibitors undergoing clinical and preclinical studies are toxic in animals. Hence, there is a critical need to identify PI3K inhibitor(s) of natural origin. The current study aims to explore the efficacy of the red algae Gelidiella acerosaon inhibition of cell proliferation, migration and the expression of cell survival genes in lung adenocarcinoma cell line A549. METHODS: The phytoconstituents of Gelidiella acerosa were extracted sequentially with solvents of different polarity, screened qualitatively and quantitatively for secondary metabolites and characterized by GC-MS. The in-vitro studies were performed to check the efficacy of the extract on cell proliferation (MTT assay), cell invasion (scratch assay and colony formation assay), apoptosis (fluorescent, confocal microscopy and flow cytometry) and expression of apoptosis and cell survival proteins including PI3K, Akt and GSK3ß and matrix metalloproteinase MMP2 and MMP9 by Western blot method. The antitumor activity of GAE was analyzed in a tumor model of Zebrafish. RESULTS: The outcomes of the in vitro analysis showed an inhibition of cell proliferation, induction of apoptosis, inhibition of cell migration and colonization by the crude extract. The analysis of protein expression showed the activation of caspases 3 and Pro apoptotic protein Bax accompanied by decreased expression of Bcl-2 and Bcl-XL. On the other hand, subsequent activation of GSK3ß and down regulation of PI3K, Akt were observed. The decreased expression of MMP2 correlated with the antimetastatic activity of the extract. The in vivo studies showed an inhibition of tumor growth by GAE in Zebrafish. CONCLUSION: The phytoconstituents of algal extract contributed to the anticancer properties as evidenced by in vitro and in vivo studies. These phytoconstituents can be considered as a natural source of PI3K/Akt inhibitor for treatment of cancers involving the PI3K cascade.

Ultra-microsecond pulsed curcumin for effective treatment of triple negative breast cancers.

Triple negative breast cancer (TNBC) is difficult to treat due to lack of the three receptors, commonly used for treating breast cancers. Current standard of cure is either ineffective or refractive to many patients. Thus, there is a critical need for alternate, affordable therapies for TNBC cancers. Towards this, electrical pulse-mediated chemotherapy, known as electrochemotherapy is a viable option, because it uses the synergy of electrical pulses and the anticancer properties of chemo drug. Considering the cost and the harsh side effects of various commonly administered chemo drugs, in this study, low cost, yet effective, natural phytochemical curcumin is studied for its anticancer effect on MDA-MB-231, TNBC cells. We applied eight 10 µs, 2500 V/cm or 5000 V/cm pulses with 10 µM concentration of curcumin, and measured cell viability and cytotoxicity. Results indicate that cell survival, as low as 4% was induced by 5000 V/cm pulses, after 72 h, while it was 15% after 24 h. This demonstrates the potential of this treatment for TNBC and the transfer to clinical practice.

Nanosecond electroporation: another look.

As the medical field moves from treatment of diseases with drugs to treatment with genes, safe and efficient gene delivery systems are needed to make this transition. One such safe, non-viral, and efficient gene delivery system is electroporation (electrogenetherapy). Exciting discoveries using electroporation could make this technique applicable to drug and vaccine delivery in addition to gene delivery. Typically milli and microsecond pulses have been used for electroporation. Recently, the use of nanosecond electrical pulses (10-300 ns) at very high magnitudes (10-300 kV/cm) has been studied for direct DNA transfer to the nucleus in vitro. This article reviews the work done using high-intensity nanosecond pulses, termed as nanosecond electroporation (nsEP), in electroporation gene delivery systems.

Nanoelectroporation: a first look.

As the medical field moves from treatment of diseases with drugs to treatment with genes, safe and efficient gene delivery systems are needed to make this transition. One such safe, nonviral, and efficient gene delivery system is electroporation (electrogenetherapy). Exciting discoveries by using electroporation could make this technique applicable to drug and vaccine delivery in addition to gene delivery. Typically, milli- and microsecond pulses have been used for electroporation. Recently, the use of nanosecond electric pulses (10-300 ns) at very high magnitudes (10-300 kV/cm) has been studied for direct DNA transfer to the nucleus in vitro. This article reviews the work done using high intensity, nanopulses, termed as nanoelectroporation (nano-EP), in electroporation gene delivery systems.