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Tumor Treating Fields (TTFields), an approved therapy for glioblastoma (GBM) and malignant mesothelioma, employ noninvasive application of low-intensity, intermediate-frequency, alternating electric fields to disrupt the mitotic spindle, leading to chromosome missegregation and apoptosis. Emerging evidence suggests that TTFields may also induce inflammation. However, the mechanism underlying this property and whether it can be harnessed therapeutically are unclear. Here, we report that TTFields induced focal disruption of the nuclear envelope, leading to cytosolic release of large micronuclei clusters that intensely recruited and activated 2 major DNA sensors - cyclic GMP-AMP synthase (cGAS) and absent in melanoma 2 (AIM2) - and their cognate cGAS/stimulator of interferon genes (STING) and AIM2/caspase 1 inflammasomes to produce proinflammatory cytokines, type 1 interferons (T1IFNs), and T1IFN-responsive genes. In syngeneic murine GBM models, TTFields-treated GBM cells induced antitumor memory immunity and a cure rate of 42% to 66% in a STING- and AIM2-dependent manner. Using single-cell and bulk RNA sequencing of peripheral blood mononuclear cells, we detected robust post-TTFields activation of adaptive immunity in patients with GBM via a T1IFN-based trajectory and identified a gene panel signature of TTFields effects on T cell activation and clonal expansion. Collectively, these studies defined a therapeutic strategy using TTFields as cancer immunotherapy in GBM and potentially other solid tumors.

Poor central nervous system penetration of cytotoxic drugs due to the blood brain barrier (BBB) is a major limiting factor in the treatment of brain tumors. Most recurrent glioblastomas (GBM) occur within the peritumoral region. In this study, we describe a hyperthemic method to induce temporary disruption of the peritumoral BBB that can potentially be used to enhance drug delivery. Twenty patients with probable recurrent GBM were enrolled in this study. Fourteen patients were evaluable. MRI-guided laser interstitial thermal therapy was applied to achieve both tumor cytoreduction and disruption of the peritumoral BBB. To determine the degree and timing of peritumoral BBB disruption, dynamic contrast-enhancement brain MRI was used to calculate the vascular transfer constant (Ktrans) in the peritumoral region as direct measures of BBB permeability before and after laser ablation. Serum levels of brain-specific enolase, also known as neuron-specific enolase, were also measured and used as an independent quantification of BBB disruption. In all 14 evaluable patients, Ktrans levels peaked immediately post laser ablation, followed by a gradual decline over the following 4 weeks. Serum BSE concentrations increased shortly after laser ablation and peaked in 1-3 weeks before decreasing to baseline by 6 weeks. The data from our pilot research support that disruption of the peritumoral BBB was induced by hyperthemia with the peak of high permeability occurring within 1-2 weeks after laser ablation and resolving by 4-6 weeks. This provides a therapeutic window of opportunity during which delivery of BBB-impermeant therapeutic agents may be enhanced. ClinicalTrials.gov NCT01851733.

Cyclin-dependent kinases 4 and 6 (CDK4/6) play critical roles in the G1 to S checkpoint of the cell cycle and have been shown to be overactive in several human cancers. Small-molecule inhibitors of CDK4/6 have demonstrated significant efficacy against many solid tumors. Since CDK4/6 inhibition is thought to induce cell cycle arrest at the G1/S checkpoint, much interest has been focused on combining CDK4/6 inhibitors with cytotoxic agents active against the S or M phase of the cell cycle to enhance therapeutic efficacy. However, it remains unclear how best to combine these two classes of drugs to avoid their potentially antagonistic effects. Here, we test various combinations of highly selective and potent CDK4/6 inhibitors with commonly used cytotoxic drugs in several cancer cell lines derived from lung, breast and brain cancers, for their cell-killing effects as compared to monotherapy. All combinations, either concurrent or sequential, failed to enhance cell-killing effects. Importantly, in certain schedules, especially pre-treatment with a CDK4/6 inhibitor, combining these drugs resulted in reduced cytotoxicity of cytotoxic agents. These findings urge cautions when combining these two classes of agents in clinical settings.

Accumulating evidence suggests cancer cells exhibit a dependency on metabolic pathways regulated by nicotinamide adenine dinucleotide (NAD⁺). Nevertheless, how the regulation of this metabolic cofactor interfaces with signal transduction networks remains poorly understood in glioblastoma. Here, we report nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting step in NAD⁺ synthesis, is highly expressed in glioblastoma tumors and patient-derived glioblastoma stem-like cells (GSCs). High NAMPT expression in tumors correlates with decreased patient survival. Pharmacological and genetic inhibition of NAMPT decreased NAD⁺ levels and GSC self-renewal capacity, and NAMPT knockdown inhibited the in vivo tumorigenicity of GSCs. Regulatory network analysis of RNA sequencing data using GSCs treated with NAMPT inhibitor identified transcription factor E2F2 as the center of a transcriptional hub in the NAD⁺-dependent network. Accordingly, we demonstrate E2F2 is required for GSC selfrenewal. Downstream, E2F2 drives the transcription of members of the inhibitor of differentiation (ID) helix–loop–helix gene family. Finally, we find NAMPT mediates GSC radiation resistance. The identification of a NAMPT-E2F2-ID axis establishes a link between NAD+ metabolism and a self-renewal transcriptional program in glioblastoma, with therapeutic implications for this formidable cancer.

With improving biofabrication technology, 3D bioprinted constructs increasingly resemble real tissues. However, the fundamental principles describing how cell-generated forces within these constructs drive deformations, mechanical instabilities, and structural failures have not been established, even for basic biofabricated building blocks. Here we investigate mechanical behaviours of 3D printed microbeams made from living cells and extracellular matrix, bioprinting these simple structural elements into a 3D culture medium made from packed microgels, creating a mechanically controlled environment that allows the beams to evolve under cell-generated forces. By varying the properties of the beams and the surrounding microgel medium, we explore the mechanical behaviours exhibited by these structures. We observe buckling, axial contraction, failure, and total static stability, and we develop mechanical models of cell-ECM microbeam mechanics. We envision these models and their generalizations to other fundamental 3D shapes to facilitate the predictable design of biofabricated structures using simple building blocks in the future. Advances in biofabrication technology enable 3D printed constructs to resemble real tissues, but it remains unclear how cell-generated forces deform these constructs. Here the authors investigate mechanical behaviours of 3D printed “microbeams” made from mixtures of living cells and extracellular matrix.

Breast cancer represents a significant therapeutic challenge due to its aggressive nature and resistance to treatment. A major cause of treatment failure in breast cancer is the presence of rare, low-proliferative disseminated tumor cells (DTCs) in distant organs including the bone marrow. This study introduced a microfluidic-based approach to improve the immunodetection and isolation of these rare DTCs for downstream analysis, with an emphasis on optimizing immunocapture, release, and enrichment methods of live DTCs as compared to the standard approach for blood-borne circulating tumor cells (CTCs). EGFR (epidermal growth factor receptor) and EpCAM (epithelial cell adhesion molecule), two key cell surface markers in breast cancer, were validated as efficient cell capture targets for DTCs within microfluidic chambers. Furthermore, we demonstrated that a combination of 0.25% trypsin and impulse was the most effective for releasing captured cells, maintaining high viability, and preserving essential cellular characteristics. Using a metastatic mouse breast cancer model, we achieved a 47.9-fold enrichment of live DTCs. Analysis of blood and bone marrow samples obtained from a breast cancer patient with minimal residual disease at two timepoints revealed a reduction in CTCs and an increase in DTCs following adjuvant chemotherapy. This observation suggested a potential dynamic interplay between CTCs and DTCs in response to therapy. Our results underscore the potential of the microfluidic approach in enhancing DTC detection and shed light on the importance of monitoring both CTCs and DTCs in breast cancer prognosis and treatment response assessment.

Immune checkpoint inhibitors (ICIs) show minimal efficacy in recurrent high-grade astrocytoma (rHGA). Laser interstitial thermal therapy (LITT), a minimally invasive cytoreductive approach, may prime rHGA for ICI response. A phase 1/randomized phase 2b trial (ClinicalTrials.gov: NCT02311582 ) was designed to test pembrolizumab in combination with LITT in patients with rHGA. Nine patients were enrolled in the phase I dose-escalation lead-in study. No dose-limiting toxicities were observed and 200 mg of pembrolizumab every three weeks was determined as the recommended phase 2 dose. The phase 2b study was initially designed to randomize (up to 45) patients 1:1 to either LITT followed by pembrolizumab (LITT + PEM) or non-LITT surgery followed by pembrolizumab (NLS + PEM). Phase 2’s primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), safety, and immune signature. After 21 patients, based on an independent Data and Safety Monitoring Committee request of unscheduled interim review of accumulating efficacy data, randomization stopped as benefit from NLS + PEM appeared limited, and the subsequent 24 patients received LITT + PEM. The pre-specified study endpoints were achieved. Among 39 per-protocol patients, LITT + PEM (n = 33) improved median OS (11.8 versus 5.2 months) and 18-month survival (42% versus 0%) compared to NLS + PEM (n = 6) (hazard ratio [HR] 0.17; 95% confidence interval [CI], 0.06–0.49; P = 0.0002). Median PFS was longer in LITT + PEM (4.5 versus 1.6 months; HR 0.21; 95% CI, 0.08–0.56; P = 0.0006). In an intent-to-treat sensitivity analysis (n = 21), OS (HR 0.29; 95% CI, 0.10–0.88) and PFS (HR 0.30; 95% CI, 0.10–0.87) again favored LITT + PEM (n = 13). Treatment was well tolerated. LITT activated non-classical monocytes, and pembrolizumab unleashed CD8⁺ T cell proliferation, clonal expansion, and coordinated memory T-cell responses. Overall, LITT + PEM is safe and may overcome rHGA immunosuppression to generate antitumor immunity. Immune checkpoint inhibitors (ICIs) have shown limited efficacy in recurrent high-grade astrocytoma (rHGA). Here the authors report the results of a Phase 1/randomized Phase 2b trial of laser interstitial thermal therapy followed by anti-PD1 pembrolizumab in patients with rHGA.

Introduction Laser interstitial thermal therapy (LITT) remains a promising advance in the treatment of primary central nervous system malignancies. As indications for its use continue to expand, there has been growing interest in its ability to induce prolonged blood brain barrier (BBB) permeability through hyperthermia, potentially increasing the effectiveness of current therapeutics including BBB-impermeant agents and immunotherapy platforms.MethodsIn this review, we highlight the mechanism of hyperthermic BBB disruption and LITT-induced immunogenic cell death in preclinical models and humans. Additionally, we summarize ongoing clinical trials evaluating a combination approach of LITT and immunotherapy, which will likely serve as the basis for future neuro-oncologic treatment paradigms.ResultsThere is evidence to suggest a highly immunogenic response to laser interstitial thermal therapy through activation of both the innate and adaptive immune response. These mechanisms have been shown to potentiate standard methods of oncologic care. There are only a limited number of clinical trials are ongoing to evaluate the utility of LITT in combination with immunotherapy.ConclusionLITT continues to be studied as a possible technique to bridge the gap between exciting preclinical results and the limited successes seen in the field of neuro-oncology. Preliminary data suggests a substantial benefit for use of LITT as a combination therapy in several clinical trials. Further investigation is required to determine whether or not this treatment paradigm can translate into long-term durable results for primary intracranial malignancies.

Purpose To determine whether participation in a clinical trial was associated with improved survival in patients with glioblastoma (GBM). Methods Following IRB approval, patients were identified using CPT and ICD codes. Data was collected using retrospective review of electronic medical records. When necessary, death data was obtained from online obituaries. Inverse propensity score matching was utilized to transform the two cohorts to comparable sets. Survival was compared using Kaplan-Meyer curves and Wilcoxon Rank Sum Test. Results In this cohort of 365 patients, 89 were enrolled in a clinical trial and 276 were not. Patients enrolled in clinical trials had a significantly higher mean baseline KPS score, higher proportion of surgical resections, and were more likely to receive temozolomide treatment than patients not enrolled in a clinical trial. After inverse propensity score matching, patients enrolled in a clinical trial lived significantly longer than those not enrolled (28.8 vs 22.2 months, p = 0.005). A potential confounder of this study is that patients not in a clinical trial had significantly fewer visits with neuro-oncologists than patients enrolled in a clinical trial (7 ± 8 vs 12 ± 9, p < 0. 0001). Conclusions Clinical trials enroll patients with the most favorable prognostic features. Even when correcting for this bias, clinical trial enrollment is an independent predictor of increased survival regardless of treatment arm.

Disulfiram, a generic alcohol aversion drug, has promising preclinical activity against glioblastoma (GBM). This phase I study aims to evaluate its safety, maximum tolerated dose (MTD), pharmacodynamic effect, and preliminary efficacy when combined with adjuvant temozolomide in GBM patients after standard chemoradiotherapy. Patients received disulfiram 500–1000 mg once daily, in combination with 150–200 mg/m 2 temozolomide. A modified 3 + 3 dose-escalation design was used to determine the MTD. The pharmacodynamic effect of proteasome inhibition was assessed using fluorometric 20S proteasome assay on peripheral blood cells. The MTD was determined based on the dose-limiting toxicities (DLTs) within the first month of therapy. Twelve patients were enrolled to two dose levels: 500 and 1000 mg. Two DLTs of grade 3 delirium occurred after 15 days of administration at 1000 mg per day. Other possible grade 2–3 DSF-related toxicities included fatigue, ataxia, dizziness, and peripheral neuropathy. The toxicities were self-limiting or resolved after discontinuing DSF. The MTD was determined to be 500 mg per day. Limited proteasome inhibition was observed at week 4 and showed an increased trend with escalated disulfiram. Median progression-free survival with 500 mg of DSF was 5.4 months from the start of disulfiram and 8.1 months from the start of chemoradiotherapy. Disulfiram can be safely combined with temozolomide but can cause reversible neurological toxicities. The MTD of disulfiram with adjuvant temozolomide appears to produce limited proteasome inhibition on peripheral blood cells.