scholarly journals EXTH-34. IN VITRO TUMOR TREATING FIELDS (TTFIELDS) APPLIED PRIOR TO RADIATION ENHANCES THE RESPONSE TO RADIATION IN PATIENT-DERIVED GLIOBLASTOMA CELL LINES

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi89-vi89
Author(s):  
Sharon Michelhaugh ◽  
Sandeep Mittal
Keyword(s):  
Cell Lines ◽  
Crystal Violet ◽  
Clonogenic Assay ◽  
Recurrent Glioblastoma ◽  
Control Group ◽  
Newly Diagnosed ◽  
Tumor Treating Fields ◽  
Cell Counts ◽  
Newly Diagnosed Glioblastoma

Abstract Tumor treating fields are FDA-approved for treatment of newly-diagnosed and recurrent glioblastoma. Adding TTFields therapy to standard-of-care extended progression-free survival and overall survival in newly-diagnosed glioblastoma patients. In this study, cell lines generated from newly-diagnosed glioblastoma patients were treated in vitro with TTFields prior to irradiation to determine if the response to radiation would be altered. This study was approved by the WSU Institutional Review Board and written consent obtained from the patients. Single-cell suspensions generated from tumor tissues obtained from newly-diagnosed patients were cultured in DMEM/F12 media with 10% fetal bovine serum and gentamicin. Prior to TTFields initiation, cells were plated on plastic coverslips (5×104cells/coverslip) and incubated overnight. Then, TTFields were applied at 200 kHz with a field intensity of ~1.6 V/cm for 3 days. After TTFields application, cells were irradiated with 2, 4, or 6 Gy, or were untreated. After radiation delivery, cells were harvested and replated in a clonogenic assay. From each group, 3 coverslips were each replated in triplicate. After 3 days (3 doubling times), cells were stained with crystal violet and plates were scanned to determine cell counts. Treatment groups were compared to their control group with t-test. For both patient-derived GBM cell lines tested, TTFields prior to radiation decreased the number of crystal violet-stained cells in the clonogenic assay plates. In cell line 15–037, pretreatment with TTFields decreased cell counts by 16, 29, and 56% after 2, 4, or 6 Gy radiation, respectively, compared to the control cells with no TTFields pretreatment (p< 0.05). The response in 14-015S cells was less radiation dose-dependent, with the decrease in cell counts ranging from 33–47% control across the radiation doses (p< 0.05). These data suggest that the use of TTFields therapy prior to radiotherapy may enhance the response to radiotherapy in GBM patients.

CBIO-02. IN VITRO TUMOR TREATING FIELDS (TTFields) REDUCE PROLIFERATION AND ALTER MLH1 EXPRESSION IN TEMOZOLOMIDE RESISTANT (TMZR) PATIENT-DERIVED GLIOBLASTOMA (GBM) CELLS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi27-vi27
Author(s):  
Sharon Michelhaugh ◽  
Katherine Degen ◽  
Blake Walker ◽  
Sandeep Mittal
Keyword(s):  
Dna Methyltransferase ◽  
Clonogenic Assay ◽  
Control Cell ◽  
Acquired Resistance ◽  
Dna Mismatch ◽  
Methylguanine Dna Methyltransferase ◽  
Tumor Treating Fields ◽  
Cell Counts ◽  
Repair Protein

Abstract BACKGROUND TTFields therapy is approved as a monotherapy for the treatment of recurrent GBM, tumors that often have acquired resistance to TMZ. To examine TTFields efficacy in the context of TMZR in vitro, TTFields were applied to TMZR GBM cells to assess proliferation, clonogenicity, and changes in expression of O6-methylguanine-DNA methyltransferase (MGMT) that confers TMZ resistance and DNA Mismatch Repair Protein Mlh1 (MLH1) that may confer TMZ sensitivity. METHODS 15-037 GBM cells were isolated from a newly-diagnosed patient tumor (IDH-WT, unmethylated MGMT promoter. Cells were grown in DMEM/F12 media with 10% FBS and gentamicin. U-251 MG cells and 15-037 cells were incubated with 100 µM TMZ for three 5-day cycles to establish TMZR. TMZR cells were plated on coverslips (1×104cells/coverslip) and incubated overnight prior to TTFields application. TTFields were applied at 200 kHz (field intensity of ~1.6 V/cm) for 14 days. Then coverslips (n=3/group) were harvested, counted, and replated for clonogenic assay at 1000 cells/35mm2 well. Clonogenic assay plates were stained with crystal violet, imaged, and colonies counted. Additional coverslips (n=3/group) were harvested and MGMT and MLH1 expression were assessed by qRT-PCR with the delta-delta Ct method using GAPDH as housekeeping control. Cell counts and colony counts were compared with two-tailed t-test with significance at p&lt; 0.05. RESULTS In U-251 MG and 15-037 TMZR cells, TTFields application significantly reduced both cell counts and clonogenic assay colony counts compared to untreated controls (U-251 MG: 45.4% and 26.5%; 15-037: 96.2% and 60.9%, respectively, p&lt; 0.05). In both TMZR cell lines, MGMT expression was unchanged by TTFields, but MLH1 expression increased 2.2 fold in U-251 MG cells and 7.1 fold in 15-037 cells after TTFields application. CONCLUSIONS Not only are TMZR GBM cells sensitive to TTFields in vitro, but TTFields increased expression of MLH1 which may be able to reduce resistance to TMZ.

scholarly journals Phase I/IIa Study of Cilengitide and Temozolomide With Concomitant Radiotherapy Followed by Cilengitide and Temozolomide Maintenance Therapy in Patients With Newly Diagnosed Glioblastoma

2010 ◽  
Vol 28 (16) ◽  
pp. 2712-2718 ◽  
Author(s):  
Roger Stupp ◽  
Monika E. Hegi ◽  
Bart Neyns ◽  
Roland Goldbrunner ◽  
Uwe Schlegel ◽  
...  
Keyword(s):  
Phase I ◽  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Progression Free Survival ◽  
Recurrent Glioblastoma ◽  
Mgmt Promoter Methylation ◽  
Newly Diagnosed ◽  
Mgmt Promoter ◽  
Newly Diagnosed Glioblastoma

Purpose Invasion and migration are key processes of glioblastoma and are tightly linked to tumor recurrence. Integrin inhibition using cilengitide has shown synergy with chemotherapy and radiotherapy in vitro and promising activity in recurrent glioblastoma. This multicenter, phase I/IIa study investigated the efficacy and safety of cilengitide in combination with standard chemoradiotherapy in newly diagnosed glioblastoma. Patients and Methods Patients (age ≥ 18 to ≤ 70 years) were treated with cilengitide (500 mg) administered twice weekly intravenously in addition to standard radiotherapy with concomitant and adjuvant temozolomide. Treatment was continued until disease progression or for up to 35 weeks. The primary end point was progression-free survival (PFS) at 6 months. Results Fifty-two patients (median age, 57 years; 62% male) were included. Six- and 12-month PFS rates were 69% (95% CI, 54% to 80%) and 33% (95% CI, 21% to 46%). Median PFS was 8 months (95% CI, 6.0 to 10.7 months). Twelve- and 24-month overall survival (OS) rates were 68% (95% CI, 53% to 79%) and 35% (95% CI, 22% to 48%). Median OS was 16.1 months (95% CI, 13.1 to 23.2 months). PFS and OS were longer in patients with tumors with O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation (13.4 and 23.2 months) versus those without MGMT promoter methylation (3.4 and 13.1 months). The combination of cilengitide with temozolomide and radiotherapy was well tolerated, with no additional toxicity. No pharmacokinetic interactions between temozolomide and cilengitide were identified. Conclusion Compared with historical controls, the addition of concomitant and adjuvant cilengitide to standard chemoradiotherapy demonstrated promising activity in patients with glioblastoma with MGMT promoter methylation.

The combined treatment of 150 kHz tumor treating fields (TTFields) and sorafenib inhibits hepatocellular carcinoma in vitro and in vivo.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15653-e15653 ◽  
Author(s):  
Uri Weinberg ◽  
Shiri Davidi ◽  
Catherine Tempel- Brami ◽  
Mijal Munster ◽  
Karnit Gotlib ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Combined Treatment ◽  
Control Group ◽  
Multikinase Inhibitor ◽  
Tumor Treating Fields ◽  
Cell Counts ◽  
Drug Concentrations ◽  
Clonogenic Potential ◽  
Hcc Cells

e15653 Background: Hepatocellular carcinoma (HCC) is the third cause of cancer related mortality and the primary cause of cancer death. Tumor Treating Fields (TTFields) therapy is an effective anti-neoplastic treatment modality delivered via noninvasive application of low intensity, intermediate frequency, alternating electric fields. Sorafenib, an oral multikinase inhibitor is approved for patients with advanced HCC, yet its survival benefit is still limited. In this work we explored the potential of the use of TTFields alone and in combination with Sorafenib as a treatment for HCC. Methods: HepG2 and Huh-7D12 cells were treated with various TTFields frequencies for 72 hours using the inovitro system. Efficacy of the combined treatment of TTFields and Sorafenib (36-3000 nM) was tested by applying TTFields at the optimal frequency together with various drug concentrations. Cell counts, induction of apoptosis, cell cycle and clonogenic potential were determined. TTFields (1.2 V/cm) and Sorafenib (10 mg/kg) were applied for 6 days to rats injected to the liver with N1S1 HCC cells. Tumor growth was followed using MRI. Results: The optimal TTFields frequency was 150 kHz for both cell lines. TTFields application (1.0 - 1.7 V/cm, 72 hours) at 150 kHz led to 36-40% reduction in cell counts and to additional reduction of over 70% in the clonogenic potential. The combined treatment of TTFields and Sorafenib led to a significant reduction in the number of cells (p < 0.001) as compared to each treatment alone. The averaged tumor volume fold increase of the combination treatment group was significantly lower than the one observed in the: control group, the TTFields group and the Sorafenib group. Conclusions: The results presented in this work demonstrate that TTFields can be an effective treatment against HCC cells and that the combination with Sorafenib may further enhance treatment efficacy.

scholarly journals EXTH-69. INCREASED CANCER CELL PERMEABILITY FOLLOWING TUMOR TREATING FIELDS (TTFIELDS) APPLICATION IN VITRO

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii102-ii102
Author(s):  
Tali Voloshin ◽  
Yaara Porat ◽  
Noa Kaynan ◽  
Anat Klein-Goldberg ◽  
Rom Paz ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Cell Permeability ◽  
Intracellular Accumulation ◽  
Optimal Frequency ◽  
Tumor Treating Fields ◽  
Cell Counts ◽  
Cellular Permeability ◽  
Resistant Cells

Abstract INTRODUCTION Tumor Treating Fields (TTFields), encompassing alternating electric fields within the intermediate frequency range, is an anticancer treatment delivered to the tumor region through transducer arrays placed non-invasively on the skin. This novel loco-regional treatment has demonstrated efficacy and safety and is FDA-approved in patients with glioblastoma (GBM) and malignant pleural mesothelioma. TTFields are currently being investigated in other solid tumors in ongoing trials. Recently, TTFields were reported to alter the cellular membrane structure of GBM cells, rendering them more permeable. The objective of this study was to characterize TTFields-induced cellular permeability in cancerous cell lines. METHODS TTFields were applied to uterine sarcoma, glioblastoma, and breast adenocarcinoma cell lines across a range of frequencies (50–500 kHz). Cellular permeability was assessed by quantifying the percentages of cells with accumulated 7-aminoactinomycin D (7-AAD) using flow cytometry and cytotoxicity was assessed based on cell counts. Kinetics were determined using different 7-AAD exposure times relative to TTFields treatment end. Changes in intracellular accumulation of anthracycline chemotherapeutics were evaluated in chemotherapy-sensitive and chemotherapy-resistant cells. RESULTS TTFields induced cellular permeability to 7-AAD in all 4 cancer cell lines tested. The optimal frequency for TTFields-induced cellular permeability was different from the optimal cytotoxic frequency. Kinetics measurements demonstrated that TTFields-induced permeability is transient and is effective only during application of TTFields. In combination experiments, TTFields improved intracellular accumulation of chemotherapeutic agents. Furthermore, combining chemotherapy with TTFields treatment facilitated accumulation of chemotherapeutics in chemotherapy-resistant cells to levels comparable with accumulation in chemotherapy-sensitive cancer cells. CONCLUSIONS This study demonstrates that TTFields can transiently increase cancer cell permeability in vitro with an optimal frequency that is variable from the frequency that is used to induce cancer cell cytotoxicity. Moreover, this effect is reversible and cellular permeability is restored to a normal state upon TTFields treatment cessation.

scholarly journals NIMG-37. DELAYED PSEUDOPROGRESSION IN TWO PATIENTS UNDERGOING TTFIELDS TREATMENT FOR NEWLY DIAGNOSED GLIOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii155-ii156
Author(s):  
Allison Lowman ◽  
Sarah Hurrell ◽  
Samuel Bobholz ◽  
Jennifer Connelly ◽  
Elizabeth Cochran ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Radiographic Progression ◽  
Methylation Status ◽  
Underlying Mechanism ◽  
Recurrent Glioblastoma ◽  
Newly Diagnosed ◽  
Methylguanine Dna Methyltransferase ◽  
Specific Effects ◽  
Newly Diagnosed Glioblastoma ◽  
Associated Risk Factors

Abstract PURPOSE Tumor treatment fields (TTFields) are approved by the FDA for newly diagnosed as well as recurrent glioblastoma (GBM). TTFields have been shown to extend survival by 4.9 months in newly diagnosed GBM, and a landmark overall survival rate of 13% at 5 years. However, the specific effects remain widely unknown, which has prevented widespread clinical use of this treatment. METHODS This case study examines two glioblastoma patients, IDH-1 wildtype, MGMT unmethylated, that received TTFields (Optune) in addition to maintenance temozolomide (TMZ) following radiation (RT). Both cases were followed using standard MR imaging. Second resections were performed due to radiographic progression of contrast enhancement. RESULTS Although imaging was concerning for tumor progression, pathology showed only treatment effect, ultimately leading to the diagnosis of pseudoprogression. Both patients fell outside the normal expected timeline for chemo-radiation induced pseudoprogression. Based on the pathology, both patients resumed treatment with TMZ/TTFields. One patient expired at 25 months and one is still alive. CONCLUSIONS Pathologic confirmation was essential for guiding further treatment and allowed patients to continue treatment that was effective despite contrary indications on imaging. These findings suggest that pathological confirmation should be strongly considered in patients receiving TMZ/TTFields who develop radiographic progression, potentially with a less invasive biopsy procedure. Future studies should look to characterize the underlying mechanism of interaction between TTFields/TMZ and quantify the prevalence, associated risk factors and whether there is a genotype more susceptible. Both patients reported here had O(6)-methylguanine-DNA methyltransferase (MGMT) unmethylated GBM, and while about 60% of glioblastomas are diagnosed likewise, it is possible that MGMT methylation status plays a role in TTFields response. Better characterization of this phenomenon will improve treatment guidance, potentially reducing unnecessary surgeries and the discontinuance of successful therapies.

RADT-13. SPARE TRIAL: SCALP-SPARING RADIATION WITH CONCURRENT TEMOZOLOMIDE AND TUMOR TREATING FIELDS FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi43-vi44
Author(s):  
Ryan Miller ◽  
Andrew Song ◽  
Ayesha S Ali ◽  
Voichita Bar-Ad ◽  
Nina, L Martinez ◽  
...  
Keyword(s):  
Radiation Treatment ◽  
Methylation Status ◽  
Treatment Interruption ◽  
Newly Diagnosed ◽  
Entire Cohort ◽  
Tumor Treating Fields ◽  
Newly Diagnosed Glioblastoma ◽  
Prospective Trials ◽  
Dose Constraints ◽  
Topical Medications

Abstract INTRODUCTION Current adjuvant treatment for patients with newly diagnosed glioblastoma includes concurrent chemoradiation and maintenance temozolomide with Tumor Treating Fields (TTFields). We report our clinical trial evaluating feasibility and tolerability of scalp-sparing radiation with concurrent temozolomide and TTFields. METHODS Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma with a KPS of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with temozolomide (75 mg/m2 daily) and TTFields (200 kHz). Maintenance therapy included temozolomide and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. The primary endpoint was safety and toxicity of tri-modality treatment within 30 days of completion of chemoradiation treatment. RESULTS Thirty patients were enrolled. Twenty were male and ten were female, with a median age of 58 years (range 19 to 77 years). Median follow-up was 10.8 months (range 1.6 to 21.3 months). Twenty (66.7%) patients had unmethylated MGMT promotor and ten (33.3%) patients had methylated promoter. Scalp dose constraints were achieved for all patients. Skin adverse events (erythema, dermatitis, irritation, folliculitis) were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. No patient had radiation treatment interruption due to skin AEs. Other Grade 1 events included pruritus (33.3%), fatigue (30%), nausea (13.3%), headache (10%), dizziness (6.7%), and cognitive impairment (3.3%). Other Grade 2 events included headache (3.3%). The median PFS for the entire cohort was 9.1 months (at least 8.5 months, 95% confidence). The median PFS for patients with MGMT promoter methylation status was 11.4 months (at least 9.5 months, 95% confidence). Overall survival was not reached. CONCLUSIONS Concurrent TTFields with scalp-sparing chemoradiation is feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation.

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