Tumor Treating Fields: At the Crossroads Between Physics and Biology for Cancer Treatment

Technical note: Computational study on thermal management schemes for tumor-treating fields therapy

BACKGROUND

The study focuses on thermal management in tumor-treating fields (TTFields) therapy, crucial for patient compliance and therapeutic effectiveness. TTFields therapy, an established treatment for glioblastoma, involves applying alternating electric fields to the brain. However, managing the thermal effects generated by electrodes is a major challenge, impacting patient comfort and treatment efficiency.

PURPOSE

This research aims to explore methods for controlling temperature increases during TTFields therapy without reducing its duty cycle. The study emphasizes optimizing electrode configurations and array arrangements to mitigate temperature rise, thereby maintaining therapy effectiveness and patient compliance.

METHODS

Using a simplified multi-layer tissue model and finite element analysis, various electrode configurations and array shapes were tested in COMSOL Multiphysics v6.0. Adjustments included changing the electrode gel layer radius from 8 to 12 mm, electrode spacing, and transitioning to a more uniform array arrangement, such as a square array or a circular array.

RESULTS

The study revealed a strong correlation between high temperatures and edge current density distributions on electrodes. It was found that increasing the electrode gel layer's diameter, enlarging electrode spacing, and adopting a uniform array arrangement markedly mitigated temperature rises. By increasing the gel layer radius from the original 10 to 12 mm, a reduction in the peak temperature increases of approximately 0.3°C was observed. Changing the layout from rectangular to circular with the same area further reduced the peak temperature rise by 0.5°C. Additionally, enlarging the spacing between electrodes also contributed to temperature control. By integrating these strategies, we designed a new circular electrode array with an electrode spacing of 45 mm and a gel radius of 12 mm, successfully reducing the peak temperature from 42.1°C to 40.8°C, effectively achieving temperature control.

CONCLUSIONS

The research demonstrates that improving electrode and array configurations can effectively manage temperature in TTFields therapy without compromising treatment duration. This strategy is crucial as TTFields therapy relies on prolonged field exposure for effectiveness. The findings offer valuable insights into thermal management in electrode array design and could lead to enhanced patient compliance and treatment efficacy in TTFields therapy.

Advanced tumor electric fields therapy: A review of innovative research and development and prospect of application in glioblastoma

BACKGROUND

Glioblastoma multiforme (GBM) is an aggressive malignant tumor with a high mortality rate and is the most prevalent primary intracranial tumor that remains incurable. The current standard treatment, which involves surgery along with concurrent radiotherapy and chemotherapy, only yields a survival time of 14-16 months. However, the introduction of tumor electric fields therapy (TEFT) has provided a glimmer of hope for patients with newly diagnosed and recurrent GBM, as it has been shown to extend the median survival time to 20 months. The combination of TEFT and other advanced therapies is a promising trend in the field of GBM, facilitated by advancements in medical technology.

AIMS

In this review, we provide a concise overview of the mechanism and efficacy of TEFT. In addition, we mainly discussed the innovation of TEFT and our proposed blueprint for TEFT implementation.

CONCLUSION

Tumor electric fields therapy is an effective and highly promising treatment modality for GBM. The full therapeutic potential of TEFT can be exploited by combined with other innovative technologies and treatments.

Tumor treating fields for the treatment of glioblastoma: Current understanding and future perspectives

Background

This review focuses on the recently published evidence on tumor treating fields (TTFields) administered alone or in combination with locoregional and systemic options for treating glioblastoma (GBM) in the past ten years. The aim is to critically summarize the novelty and results obtained with this innovative tool, which is becoming part of the armamentarium of neurosurgeons and neuro-oncologists.

Methods

A comprehensive search and analysis were conducted on pivotal studies published in the past ten years. Furthermore, all completed clinical trials, whose results were published on clinicaltrials.gov, were examined and included in the present review, encompassing both recurrent (r) and newly diagnosed (n) GBM. Finally, an additional examination of the ongoing clinical trials was also conducted.

Results

Recent trials have shown promising results both in patients with nGBM and rGBM/progressive (rGBM), leading to Food and Drug Administration approval in selected patients and the Congress of Neurological Surgeons to include TTFields into current guidelines on the management of GBM (P100034/S001-029). Recently, different randomized trials have demonstrated promising results of TTFields in combination with standard treatment of n- and rGBM, especially when considering progression-free and overall survival, maintaining a low rate of mild to moderate adverse events.

Conclusion

Optimal outcomes were obtained in nGBM and progressive disease. A possible future refinement of TTFields could significantly impact the treatment of rGBM and the actual standard of care for GBM, given the better safety profile and survival effects.

A review of tumor treating fields (TTFields): advancements in clinical applications and mechanistic insights

BACKGROUND

Tumor Treating Fields (TTFields) is a non-invasive modality for cancer treatment that utilizes a specific sinusoidal electric field ranging from 100 kHz to 300 kHz, with an intensity of 1 V/cm to 3 V/cm. Its purpose is to inhibit cancer cell proliferation and induce cell death. Despite promising outcomes from clinical trials, TTFields have received FDA approval for the treatment of glioblastoma multiforme (GBM) and malignant pleural mesothelioma (MPM). Nevertheless, global acceptance of TTFields remains limited. To enhance its clinical application in other types of cancer and gain a better understanding of its mechanisms of action, this review aims to summarize the current research status by examining existing literature on TTFields' clinical trials and mechanism studies.

CONCLUSIONS

Through this comprehensive review, we seek to stimulate novel ideas and provide physicians, patients, and researchers with a better comprehension of the development of TTFields and its potential applications in cancer treatment.

The role of immune subtyping in glioma mRNA vaccine development

Studies on the development of mRNA vaccines for central nervous system tumors have used gene expression profiles, clinical data and RNA sequencing from sources such as The Cancer Genome Atlas and Chinese Glioma Genome Atlas to identify effective antigens. These studies revealed several immune subtypes of glioma, each one linked to unique prognoses and genetic/immune-modulatory changes. Potential antigens include ARPC1B, BRCA2, COL6A1, ITGB3, IDH1, LILRB2, TP53 and KDR, among others. Patients with immune-active and immune-suppressive phenotypes were found to respond better to mRNA vaccines. While these findings indicate the potential of mRNA vaccines in cancer therapy, further research is required to optimize administration and adjuvant selection, and precisely identify target antigens.

Effectiveness of tumor‑treating fields to reduce the proliferation and migration of liposarcoma cell lines

Liposarcoma (LPS) is a rare type of soft tissue sarcoma that constitutes 20% of all sarcoma cases in adults. Effective therapeutic protocols for human LPS are not well-defined. Tumor-treating fields (TTFields) are a novel and upcoming field for antitumor therapy. TTFields combined with chemoradiotherapy have proven to be more effective than TTFields combined with radiotherapy or chemotherapy alone. The present study aimed to assess the effectiveness of TTFields in inhibiting cell proliferation and viability for the anticancer treatment of LPS. The present study used TTFields (frequency, 150 kHz; intensity, 1.0 V/cm) to treat two LPS cell lines (94T778 and SW872) and analyzed the antitumor effects. According to trypan blue and MTT assay results, TTFields markedly reduced the viability and proliferation of LPS cell lines along with the formation of colonies in three-dimensional culture. Based on the Transwell chamber assay, TTFields treatment also markedly reduced the migration of LPS cells. Furthermore, as shown by the higher activation of caspase-3 in the Caspase-3 activity assay and the results of the reactive oxygen species (ROS) assay, TTFields increased the formation of ROS in the cells and enhanced the proportion of apoptotic cells. The present study also investigated the inhibitory effect of TTFields in combination with doxorubicin (DOX) on the migratory capacity of tumor cells. The results demonstrated that TTFields treatment synergistically induced the ROS-induced apoptosis of LPS cancer cell lines and inhibited their migratory behavior. In conclusion, the present study demonstrated the potential of TTFields in improving the sensitivity of LPS cancer cells, which may lay the foundation for future clinical trials of this combination treatment strategy.

Re-irradiation combined with bevacizumab for recurrent glioblastoma beyond bevacizumab failure: survival outcomes and prognostic factors

The combination of re-irradiation and bevacizumab has emerged as a potential therapeutic strategy for patients experiencing their first glioblastoma multiforme (GBM) recurrence. This study aims to assess the effectiveness of the re-irradiation and bevacizumab combination in treating second-progression GBM patients who are resistant to bevacizumab monotherapy. This retrospective study enrolled 64 patients who developed a second progression after single-agent bevacizumab therapy. The patients were divided into two groups: 35 underwent best supportive care (none-ReRT group), and 29 received bevacizumab and re-irradiation (ReRT group). The study measured the overall survival time after bevacizumab failure (OST-BF) and re-irradiation (OST-RT). Statistical tests were used to compare categorical variables, evaluate the difference in recurrence patterns between the two groups, and identify optimal cutoff points for re-irradiation volume. The results of the Kaplan-Meier survival analysis indicated that the re-irradiation (ReRT) group experienced a significantly higher survival rate and longer median survival time than the non-ReRT group. The median OST-BF and OST-RT were 14.5 months and 8.8 months, respectively, for the ReRT group, while the OST-BF for the none-ReRT group was 3.9 months (p < 0.001). The multivariable analysis identified the re-irradiation target volume as a significant factor for OST-RT. Moreover, the re-irradiation target volume exhibited excellent discriminatory ability in the area under the curve (AUC) analysis, with an optimal cutoff point of greater than 27.58 ml. These findings suggest that incorporating re-irradiation with bevacizumab therapy may be a promising treatment strategy for patients with recurrent GBM resistant to bevacizumab monotherapy. The re-irradiation target volume may serve as a valuable selection factor in determining which patients with recurrent GBM are likely to benefit from the combined re-irradiation and bevacizumab treatment modality.

Engineering the Tumor Immune Microenvironment through Minimally Invasive Interventions

The tumor microenvironment (TME) is a unique landscape that poses several physical, biochemical, and immune barriers to anti-cancer therapies. The rapidly evolving field of immuno-engineering provides new opportunities to dismantle the tumor immune microenvironment by efficient tumor destruction. Systemic delivery of such treatments can often have limited local effects, leading to unwanted offsite effects such as systemic toxicity and tumor resistance. Interventional radiologists use contemporary image-guided techniques to locally deliver these therapies to modulate the immunosuppressive TME, further accelerating tumor death and invoking a better anti-tumor response. These involve local therapies such as intratumoral drug delivery, nanorobots, nanoparticles, and implantable microdevices. Physical therapies such as photodynamic therapy, electroporation, hyperthermia, hypothermia, ultrasound therapy, histotripsy, and radiotherapy are also available for local tumor destruction. While the interventional radiologist can only locally manipulate the TME, there are systemic offsite recruitments of the immune response. This is known as the abscopal effect, which leads to more significant anti-tumoral downstream effects. Local delivery of modern immunoengineering methods such as locoregional CAR-T therapy combined with immune checkpoint inhibitors efficaciously modulates the immunosuppressive TME. This review highlights the various advances and technologies available now to change the TME and revolutionize oncology from a minimally invasive viewpoint.

Glioblastoma-Derived Three-Dimensional Ex Vivo Models to Evaluate Effects and Efficacy of Tumor Treating Fields (TTFields)

Glioblastoma (GBM) displays a wide range of inter- and intra-tumoral heterogeneity contributing to therapeutic resistance and relapse. Although Tumor Treating Fields (TTFields) are effective for the treatment of GBM, there is a lack of ex vivo models to evaluate effects on patients' tumor biology or to screen patients for treatment efficacy. Thus, we adapted patient-derived three-dimensional tissue culture models to be compatible with TTFields application to tissue culture. Patient-derived primary cells (PDPC) were seeded onto murine organotypic hippocampal slice cultures (OHSC), and microtumor development with and without TTFields at 200 kHz was observed. In addition, organoids were generated from acute material cultured on OHSC and treated with TTFields. Lastly, the effect of TTFields on expression of the Ki67 proliferation marker was evaluated on cultured GBM slices. Microtumors exhibited increased sensitivity towards TTFields compared to monolayer cell cultures. TTFields affected tumor growth and viability, as the size of microtumors and the percentage of Ki67-positive cells decreased after treatment. Nevertheless, variability in the extent of the response was preserved between different patient samples. Therefore, these pre-clinical GBM models could provide snapshots of the tumor to simulate patient treatment response and to investigate molecular mechanisms of response and resistance.

Recurrent Glioblastoma Treatment: State of the Art and Future Perspectives in the Precision Medicine Era

Current treatment guidelines for the management of recurrent glioblastoma (rGBM) are far from definitive, and the prognosis remains dismal. Despite recent advancements in the pharmacological and surgical fields, numerous doubts persist concerning the optimal strategy that clinicians should adopt for patients who fail the first lines of treatment and present signs of progressive disease. With most recurrences being located within the margins of the previously resected lesion, a comprehensive molecular and genetic profiling of rGBM revealed substantial differences compared with newly diagnosed disease. In the present comprehensive review, we sought to examine the current treatment guidelines and the new perspectives that polarize the field of neuro-oncology, strictly focusing on progressive disease. For this purpose, updated PRISMA guidelines were followed to search for pivotal studies and clinical trials published in the last five years. A total of 125 articles discussing locoregional management, radiotherapy, chemotherapy, and immunotherapy strategies were included in our analysis, and salient findings were critically summarized. In addition, an in-depth description of the molecular profile of rGBM and its distinctive characteristics is provided. Finally, we integrate the above-mentioned evidence with the current guidelines published by international societies, including AANS/CNS, EANO, AIOM, and NCCN.

Involvement of White Matter Language Tracts in Glioma: Clinical Implications, Operative Management, and Functional Recovery After Injury

To achieve optimal survival and quality of life outcomes in patients with glioma, the extent of tumor resection must be maximized without causing injury to eloquent structures. Preservation of language function is of particular importance to patients and requires careful mapping to reveal the locations of cortical language hubs and their structural and functional connections. Within this language network, accurate mapping of eloquent white matter tracts is critical, given the high risk of permanent neurological impairment if they are injured during surgery. In this review, we start by describing the clinical implications of gliomas involving white matter language tracts. Next, we highlight the advantages and limitations of methods commonly used to identify these tracts during surgery including structural imaging techniques, functional imaging, non-invasive stimulation, and finally, awake craniotomy. We provide a rationale for combining these complementary techniques as part of a multimodal mapping paradigm to optimize postoperative language outcomes. Next, we review local and long-range adaptations that take place as the language network undergoes remodeling after tumor growth and surgical resection. We discuss the probable cellular mechanisms underlying this plasticity with emphasis on the white matter, which until recently was thought to have a limited role in adults. Finally, we provide an overview of emerging developments in targeting the glioma-neuronal network interface to achieve better disease control and promote recovery after injury.

Synergetic Effect of Tumor Treating Fields and Zinc Oxide Nanoparticles on Cell Apoptosis and Genotoxicity of Three Different Human Cancer Cell Lines

Cancer remains a leading cause of death worldwide, despite extraordinary progress. So, new cancer treatment modalities are needed. Tumor-treating fields (TTFs) use low-intensity, intermediate-frequency alternating electric fields with reported cancer anti-mitotic properties. Moreover, nanomedicine is a promising therapy option for cancer. Numerous cancer types have been treated with nanoparticles, but zinc oxide nanoparticles (ZnO NPs) exhibit biocompatibility. Here, we investigate the activity of TTFs, a sub-lethal dose of ZnO NPs, and their combination on hepatocellular carcinoma (HepG2), the colorectal cancer cell line (HT-29), and breast cancer cell lines (MCF-7). The lethal effect of different ZnO NPs concentrations was assessed by sulforhodamine B sodium salt assay (SRB). The cell death percent was determined by flow cytometer, the genotoxicity was evaluated by comet assay, and the total antioxidant capacity was chemically measured. Our results show that TTFs alone cause cell death of 14, 8, and 17% of HepG2, HT-29, and MCF-7, respectively; 10 µg/mL ZnO NPs was the sub-lethal dose according to SRB results. The combination between TTFs and sub-lethal ZnO NPs increased the cell death to 29, 20, and 33% for HepG2, HT-29, and MCF-7, respectively, without reactive oxygen species increase. Increasing NPs potency using TTFs can be a novel technique in many biomedical applications.

Glioblastoma, from disease understanding towards optimal cell-based in vitro models

Background

Glioblastoma (GBM) patients are notoriously difficult to treat and ultimately all succumb to disease. This unfortunate scenario motivates research into better characterizing and understanding this disease, and into developing novel research tools by which potential novel therapeutics and treatment options initially can be evaluated pre-clinically. Here, we provide a concise overview of glioblastoma epidemiology, disease classification, the challenges faced in the treatment of glioblastoma and current novel treatment strategies. From this, we lead into a description and assessment of advanced cell-based models that aim to narrow the gap between pre-clinical and clinical studies. Such invitro models are required to deliver reliable and meaningful data for the development and pre-validation of novel therapeutics and treatments.

Conclusions

The toolbox for GBM cell-based models has expanded substantially, with the possibility of 3D printing tumour tissues and thereby replicating invivo tissue architectures now looming on the horizon. A comparison of experimental cell-based model systems and techniques highlights advantages and drawbacks of the various tools available, based on which cell-based models and experimental approaches best suited to address a diversity of research questions in the glioblastoma research field can be selected.

Planning System for the Optimization of Electric Field Delivery using Implanted Electrodes for Brain Tumor Control

BACKGROUND

The use of non-ionizing electric fields from low intensity voltage sources (<10 V) to control malignant tumor growth is showing increasing potential as a cancer treatment modality. A method of applying these low intensity electric fields using multiple implanted electrodes within or adjacent to tumor volumes has been termed as intratumoral modulation therapy (IMT).

PURPOSE

This study explores advancements in the previously established IMT optimization algorithm, and the development of a custom treatment planning system for patient specific IMT. The practicality of the treatment planning system is demonstrated by implementing the full optimization pipeline on a brain phantom with robotic electrode implantation, post-operative imaging, and treatment stimulation.

METHODS

The integrated planning pipeline in 3D Slicer begins with importing and segmenting patient magnetic resonance images (MRI) or computed tomography (CT) images. The segmentation process is manual, followed by a semi-automatic smoothing step that allows the segmented brain and tumor mesh volumes to be smoothed and simplified by applying selected filters. Electrode trajectories are planned manually on the patient MRI or CT by selecting insertion and tip coordinates for a chosen number of electrodes. The electrode tip positions, and stimulation parameters (phase shift and voltage) can then be optimized with the custom semi-automatic IMT optimization algorithm where users can select the prescription electric field, voltage amplitude limit, tissue electrical properties, nearby organs at risk, optimization parameters (electrode tip location, individual contact phase shift and voltage), desired field coverage percent, and field conformity optimization. Tables of optimization results are displayed, and the resulting electric field is visualized as a field-map superimposed on the MR or CT image, with 3D renderings of the brain, tumor, and electrodes. Optimized electrode coordinates are transferred to robotic electrode implantation software to enable planning and subsequent implantation of the electrodes at the desired trajectories.

RESULTS

An IMT treatment planning system was developed that incorporates patient specific MRI or CT, segmentation, volume smoothing, electrode trajectory planning, electrode tip location and stimulation parameter optimization, and results visualization. All previous manual pipeline steps operating on diverse software platforms were coalesced into a single semi-automated 3D Slicer based user interface. Brain phantom validation of the full system implementation was successful in pre-operative planning, robotic electrode implantation, and post-operative treatment planning to adjust stimulation parameters based on actual implant locations. Voltage measurements were obtained in the brain phantom to determine the electrical parameters of the phantom and validate the simulated electric field distribution.

CONCLUSIONS

A custom treatment planning and implantation system for IMT has been developed in this study, and validated on a phantom brain model, providing an essential step in advancing IMT technology towards future clinical safety and efficacy investigations. This article is protected by copyright. All rights reserved.

Theranostic Potential of Adaptive Cold Atmospheric Plasma with Temozolomide to Checkmate Glioblastoma: An In Vitro Study

Simple Summary

Glioblastoma (GBM) is an aggressive form of brain cancer. Here, we present a combination therapy of cold atmospheric plasma (CAP) and temozolomide (TMZ) to treat GBM in vitro. We analyze the effects of the co-treatment in two GBM (TMZ-resistant and -sensitive) cell lines. The aim of this study is mainly to sensitize these cells using CAP so that they respond well to TMZ. We further found that the removal of cell culture media after CAP treatment does not affect the sensitivity of CAP to cancer cells but enhances the effects of TMZ. However, it was observed in our study that keeping the CAP-treated media for a shorter time did not significantly inhibit T98G cells. Interestingly, keeping the same plasma-treated media for a longer duration resulted in a decrease in cell viability. On the contrary, TMZ-sensitive cell A172 responded well to the co-treatment. This could be a potential reason for the sensitization of the combination therapy.

Abstract

Cold atmospheric plasma (CAP) has been used for the treatment of various cancers. The anti-cancer properties of CAP are mainly due to the reactive species generated from it. Here, we analyze the efficacy of CAP in combination with temozolomide (TMZ) in two different human glioblastoma cell lines, T98G and A172, in vitro using various conditions. We also establish an optimized dose of the co-treatment to study potential sensitization in TMZ-resistant cells. The removal of cell culture media after CAP treatment did not affect the sensitivity of CAP to cancer cells. However, keeping the CAP-treated media for a shorter time helped in the slight proliferation of T98G cells, while keeping the same media for longer durations resulted in a decrease in its survivability. This could be a potential reason for the sensitization of the cells in combination treatment. Co-treatment effectively increased the lactate dehydrogenase (LDH) activity, indicating cytotoxicity. Furthermore, apoptosis and caspase-3 activity also significantly increased in both cell lines, implying the anticancer nature of the combination. The microscopic analysis of the cells post-treatment indicated nuclear fragmentation, and caspase activity demonstrated apoptosis. Therefore, a combination treatment of CAP and TMZ may be a potent therapeutic modality to treat glioblastoma. This could also indicate that a pre-treatment with CAP causes the cells to be more sensitive to chemotherapy treatment.

The Routine Application of Tumor-Treating Fields in the Treatment of Glioblastoma WHO° IV

Introduction:

Tumor-treating fields (TTFs) are a specific local oncological treatment modality in glioblastoma multiforme WHO° IV (GBM). Their mechanism of action is based on the effect of electrical fields interfering with the mitotic activity of malignant cells. Prospective studies have demonstrated efficacy, but TTF benefits are still controversially discussed. This treatment was implemented in our center as the standard of care in January 2016. We thus discuss the current state of the art and our long-term experience in the routine application of TTF.

Methods

The data of 48 patients suffering from GBM and treated with TTF were assessed and compared with previously published studies. Up-to-date information from open sources was evaluated.

Results

A total of 31 males and 17 females harboring a GBM were treated with TTF, between January 2016 and August 2021, in our center. In 98% of cases, TTFs were started within 6 weeks after concomitant radiochemotherapy (Stupp protocol). Mean overall survival was 22.6 months (95% CI: 17.3–27.9). Current indications, benefits, and restrictions were evaluated. Future TTF opportunities and ongoing studies were reviewed.

Conclusion

TTFs are a feasible and routinely applicable specific oncological treatment option for glioblastoma multiforme WHO° IV. Further research is ongoing to extend the indications and the efficacy of TTF.

Combination therapy of Doxorubicin with TTFields and radiation: newer approaches to combat lung cancer

BACKGROUND

Tumor-treating fields (TTFields) have been used singly or with chemoradiation for treating glioblastoma and mesothelioma but not yet for lung cancer. Survival rates in lung cancer remain abysmal despite advances in early diagnosis and targeted therapies.

AIMS AND OBJECTIVES

We aimed to investigate the effectiveness of TTFields in inhibiting lung cancer growth and metastasis, as well as the therapeutic effectiveness of TTFields alongside radiation and chemosensitivity-enhancing agents in an in vitro model.

METHODS

We generated TTFields yielding 0-800 V sine-wave signals, 0.9 V/cm applied electric field intensity, and 150 kHz frequency. The human lung cancer cell lines A549 and H460 were used in this study. Cell viability, colony formation, cell death detection, and cell invasion assays were performed to assess the therapeutic effectiveness of TTFields; sensitization of lung cancer cells to TTFields by doxorubicin (DOX); and the combined effect of TTFields, DOX, and irradiation (IR).

RESULTS

Lung cancer cells showed a nearly 20% decrease in cell viability at 1 V/cm and 150 kHz. In A549 and H460 cells, TTFields increased apoptosis through increased cleaved caspase3, hindered cell migration and invasion, and improved chemosensitivity to DOX. The combination of DOX and TTFields showed better antitumor results than those of each individually. However, the DOX/TTFields/IR combination was most effective in reducing the viability and migration of lung cancer cells.

CONCLUSION

TTFields as an adjuvant therapy offers probability for improving lung cancer patient outcomes.

The Biological and Molecular Function of LINC00665 in Human Cancers

Long non-coding RNAs (lncRNAs) are more than 200 nucleotides in length and are implicated in the development of human cancers, without protein-coding function. Mounting evidence indicates that cancer initiation and progression are triggered by lncRNA dysregulation. Recently, a growing number of studies have found that LINC00665, a long intergenic non-protein coding RNA, may be associated with various cancers, including gastrointestinal tumors, gynecological tumors, and respiratory neoplasms. LINC00665 was reported to be significantly dysregulated in cancers and has an important clinical association. It participates in cell proliferation, migration, invasion, and apoptosis through different biological pathways. In this review, we summarize the current findings on LINC00665, including its biological roles and molecular mechanisms in various cancers. LINC00665 may be a potential prognostic biomarker and novel therapeutic target for cancers.

Healing Field: Using Alternating Electric Fields to Prevent Cytokine Storm by Suppressing Clonal Expansion of the Activated Lymphocytes in the Blood Sample of the COVID-19 Patients

In the case of the COVID-19 early diagnosis, numerous tech innovations have been introduced, and many are currently employed worldwide. But, all of the medical procedures for the treatment of this disease, up to now, are just limited to chemical drugs. All of the scientists believe that the major challenge toward the mortality of the COVID-19 patients is the out-of-control immune system activation and the subsequent cytokine production. During this process, the adaptive immune system is highly activated, and many of the lymphocytes start to clonally expand; hence many cytokines are also released. So, any attempt to harness this cytokine storm and calm down the immune outrage is appreciated. While the battleground for the immune hyperactivation is the lung ambient of the infected patients, the only medical treatment for suppressing the hypercytokinemia is based on the immunosuppressor drugs that systemically dampen the immunity with many unavoidable side effects. Here, we applied the alternating electric field to suppress the expansion of the highly activated lymphocytes, and by reducing the number of the renewed cells, the produced cytokines were also decreased. Applying this method to the blood of the COVID-19 patients in vitro showed ∼33% reduction in the average concentration of the three main cytokines after 4 days of stimulation. This method could carefully be utilized to locally suppress the hyperactivated immune cells in the lung of the COVID-19 patients without any need for systemic suppression of the immune system by the chemical drugs.

Skull modulated strategies to intensify tumor treating fields on brain tumor: a finite element study

Tumor treating fields (TTFields) are a breakthrough in treating glioblastoma (GBM), whereas the intensity cannot be further enhanced, due to the limitation of scalp lesions. Skull remodeling (SR) surgery can elevate the treatment dose of TTFields in the intracranial foci. This study was aimed at exploring the characteristics of the skull modulated strategies toward TTFields augmentation. The simplified multiple-tissue-layer model (MTL) and realistic head (RH) model were reconstructed through finite element methods (FEM), to simulate the remodeling of the skull, which included skull drilling, thinning, and cranioplasty with PEEK, titanium, cerebrospinal fluid (CSF), connective tissue and autologous bone. Skull thinning could enhance the intensity of TTFields in the brain tumor, with a 10% of increase in average peritumoral intensity (API) by every 1 cm decrease in skull thickness. Cranioplasty with titanium accompanied the most enhancement of TTFields in the MTL model, but CSF was superior in TTFields enhancement when simulated in the RH model. Besides, API increased nonlinearly with the expansion of drilled burr holes. In comparison with the single drill replaced by titanium, nine burr holes could reach 96.98% of enhancement in API, but it could only reach 63.08% of enhancement under craniectomy of nine times skull defect area. Skull thinning and drilling could enhance API, which was correlated with the number and area of skull drilling. Cranioplasty with highly conductive material could also augment API, but might not provide clinical benefits as expected.

Feasibility of Tumor Treating Fields with Pemetrexed and Platinum-Based Chemotherapy for Unresectable Malignant Pleural Mesothelioma: Single-Center, Real-World Data

Simple Summary

Management of malignant pleural mesothelioma (MPM) is challenging as patients frequently present with unresectable disease and the response rates with systemic therapy alone remain low. Given the paucity of effective therapies for MPM, Tumor Treating Fields (TTFields) therapy was made available for use under an FDA-approved Humanitarian Device Exemption (HDE) protocol in 2019, but no real-world data beyond the initial trial have been published to date. We reviewed our retrospective series of five patients diagnosed with MPM and treated with TTFields with pemetrexed and platinum-based chemotherapy. This therapy resulted in a modest disease-stabilization rate with no significant device-related major toxicities. However, we observed universal low-grade skin toxicities related to the device which required medical management and self-discontinuation in 2/5 patients. We also observed lower device usage, compared to the STELLAR trial. Both of these represent opportunities for developing improved management guidelines and efforts to improve patient compliance.

Abstract

Purpose: The objectives of this study were to evaluate the implementation, device usage rates, clinical outcomes, and treatment-related toxicities associated with TTFields and pemetrexed plus platinum-based chemotherapy in patients with unresectable MPM, outside the initial trial results. Methods: Consecutive patients with unresectable MPM were enrolled onto an FDA-required HDE protocol from 2019 to 2021. All patients were treated with a protocol-defined regimen of continuous TTFields (150 kHz) and pemetrexed plus platinum-based chemotherapy. Results: Five patients with unresectable MPM were enrolled. The median number of 4-week TTFields cycles was 5 (range: 2–7 cycles). Median TTFields device usage in the first 3 months was 12.5 h per day (range: 5–16.8 h), representing 52% (21–70%) of the potential daily duration. The median follow-up was 5.4 months (range: 1.1–20.9 months). Treatment-related dermatitis was the only side effect associated with TTFields and was reported as grade 1–2 in all patients; no patient had grade 3+ device-related toxicities. Conclusions: This study represents the first results of real-world implementation of TTFields for MPM. In comparison to the initial clinical trial (STELLAR), compliance rates were lower, although skin-related toxicities appeared similar. Further initiatives and guidelines should be developed to manage treatment-related dermatitis and improve device usage.

Exploring the efficacy of tumor electric field therapy against glioblastoma: An in vivo and in vitro study

AIMS

Tumor electric fields therapy (TTFields) is emerging as a novel anti-cancer physiotherapy. Despite recent breakthroughs of TTFields in glioma treatment, the average survival time for glioblastoma patients with TTFields is <2 years, even when used in conjugation with traditional anti-cancer therapies. To optimize TTFields-afforded efficacy against glioblastoma, we investigated the cancer cell-killing effects of various TTFields paradigms using in vitro and in vivo models of glioblastoma.

METHODS

For in vitro studies, the U251 glioma cell line or primary cell cultures prepared from 20 glioblastoma patients were treated with the tumor electric field treatment (TEFT) system. Cell number, volume, and proliferation were measured after TEFT at different frequencies (100, 150, 180, 200, or 220 kHz), durations (24, 48, or 72 h), field strengths (1.0, 1.5, or 2.2V/cm), and output modes (fixed or random sequence output). A transwell system was used to evaluate the influence of TEFT on the invasiveness of primary glioblastoma cells. For in vivo studies, the therapeutic effect and safety profiles of random sequence electric field therapy in glioblastoma-transplanted rats were assessed by calculating tumor size and survival time and evaluating peripheral immunobiological and blood parameters, respectively.

RESULTS

In the in vitro settings, TEFT was robustly effective in suppressing cell proliferation of both the U251 glioma cell line and primary glioblastoma cell cultures. The anti-proliferation effects of TEFT were frequency- and "dose" (field strength and duration)-dependent, and contingent on the field sequence output mode, with the random sequence mode (TEFT-R) being more effective than the fixed sequence mode (TEFT-F). Genetic tests were performed in 11 of 20 primary glioblastoma cultures, and 6 different genetic traits were identified them. However, TEFT exhibited comparable anti-proliferation effects in all primary cultures regardless of their genetic traits. TEFT also inhibited the invasiveness of primary glioblastoma cells in transwell experiments. In the in vivo rat model of glioblastoma brain transplantation, treatment with TEFT-F or TEFT-R at frequency of 200 kHz and field strength of 2.2V/cm for 14 days significantly reduced tumor volume by 42.63% (TEFT-F vs. control, p = 0.0002) and 63.60% (TEFT-R vs. control, p < 0.0001), and prolonged animal survival time by 30.15% (TEFT-F vs. control, p = 0.0415) and 69.85% (TEFT-R vs. control, p = 0.0064), respectively. The tumor-bearing rats appeared to be well tolerable to TEFT therapies, showing only moderate increases in blood levels of creatine and red blood cells. Adverse skin reactions were common for TEFT-treated rats; however, skin reactions were curable by local treatment.

CONCLUSION

Tumor electric field treatment at optimal frequency, strength, and output mode markedly inhibits the cell viability, proliferation, and invasiveness of primary glioblastoma cells in vitro independent of different genetic traits of the cells. Moreover, a random sequence electric field output confers considerable anti-cancer effects against glioblastoma in vivo. Thus, TTFields are a promising physiotherapy for glioblastoma and warrants further investigation.

An insight into the risk factors of brain tumors and their therapeutic interventions

Brain tumors are an abnormal growth of cells in the brain, also known as multifactorial groups of neoplasm. Incidence rates of brain tumors increase rapidly, and it has become a leading cause of tumor related deaths globally. Several factors have potential risks for intracranial neoplasm. To date, the International Agency for Research on Cancer has classified the ionizing radiation and the N-nitroso compounds as established carcinogens and probable carcinogens respectively. Diagnosis of brain tumors is based on histopathology and suitable imaging techniques. Labeled amino acids and fluorodeoxyglucose with or without contrast-enhanced MRI are used for the evaluation of tumor traces. T2-weighted MRI is an advanced diagnostic implementation, used for the detection of low-grade gliomas. Treatment decisions are based on tumor size, location, type, patient's age and health status. Conventional therapeutic approaches for tumor treatment are surgery, radiotherapy and chemotherapy. While the novel strategies may include targeted therapy, electric field treatments and vaccine therapy. Inhibition of cyclin-dependent kinase inhibitors is an attractive tumor mitigation strategy for advanced-stage cancers; in the future, it may prove to be a useful targeted therapy. The blood-brain barrier poses a major hurdle in the transport of therapeutics towards brain tissues. Moreover, nanomedicine has gained a vital role in cancer therapy. Nano drug delivery system such as liposomal drug delivery has been widely used in the cancer treatment. Liposome encapsulated drugs have improved therapeutic efficacy than free drugs. Numerous treatment therapies for brain tumors are in advanced clinical research.

Observations on the anti-glioma potential of electrical fields: is there a role for surgical neuromodulation?

Alternating electrical field therapy represents a recent addition to the armamentarium against high grade glioma. Randomised trial evidence suggests a survival benefit from adjunctive scalp delivered Tumour Treating Fields (TTFields) in glioblastoma. Any underlying anti-glioma effect is not fully understood, but interference with cell division and microtubule assembly has been averred. The survival benefit claimed for TTFields is modest and is associated with mild reductions in health-related quality of life indices amid costs that presently preclude routine use. I review possible mechanisms by which alternating electrical fields may confer an anti-glioma effect. As scalp and skull are poor conductors of an electrical field, a case is made here for implantable electrodes, perhaps placed at the time of tumour debulking. Such a system may deliver an electrical field directly to the tumour resection cavity and with greater precision.