Temozolomide Chemotherapy Research Articles

Lewy body disease as a potential negative outcome modifier of glioblastoma treatment: a case report

BackgroundElderly patients with glioblastoma are particularly susceptible to the adverse effects of ionizing radiation to the brain. This population also has an increasing prevalence of dementia in the successive seventh, eighth and nineth decade of life, and dementia with Lewy bodies is characterized by pathologic α-synucleins, proteins that take part in neuronal DNA damage repair.Case presentationWe report a 77-year-old man, with a history of coronary artery disease and mild cognitive impairment, who experienced subacute behavioral changes over 3 months with wording-finding difficulty, memory loss, confusion, perseveration, and irritable mood. Neuroimaging studies disclosed a 2.5 × 2.4 × 2.7 cm cystic enhancing mass with central necrosis in the left temporal lobe of the brain. Gross total resection of the tumor revealed IDH-1 wild-type glioblastoma. After treatment with radiation and temozolomide chemotherapy, his cognitive status deteriorated rapidly, and he died from unexpected sudden death 2 months after radiation. Autopsy of his brain revealed (i) tumor cells with atypical nuclei and small lymphocytes, (ii) neuronal cytoplasmic inclusions and Lewy bodies that were positive for α-synuclein in the midbrain, pons, amygdala, putamen and globus pallidus, and (iii) no amyloid plaques and only rare neurofibrillary tangles near the hippocampi.ConclusionsThis patient most likely had pre-clinical limbic subtype of dementia with Lewy bodies prior to his diagnosis of glioblastoma. The radiation and temozolomide that was used to treat his tumor may have accelerated neuronal damage due to induction of DNA breakage when his brain was already compromised by pathologic α-synucleins. α-Synucleinopathy could be a negative outcome modifier in glioblastoma patients.

Prognostic analysis and nomogram construction for older patients with IDH-wild-type glioblastoma

As many countries face an ageing population, the number of older patients with glioblastoma (GB) is increasing. Thus, there is an urgent need for prognostic models to aid in treatment decision-making and life planning. A total of 98 patients with isocitrate dehydrogenase (IDH)-wild-type GB aged ≥65 years were analysed from January 2012 to January 2020. Independent prognostic factors were identified by prognostic analysis. Using the independent prognostic factors for overall survival (OS), a nomogram was constructed by R software to predict the prognosis of older patients with IDH-wild-type GB. The concordance index (C-index) and receiver operating characteristic (ROC) curve were used to assess model discrimination, and the calibration curve was used to assess model calibration. Prognostic analysis showed that the extent of resection (EOR), adjusted Charlson comorbidity index (ACCI), O6-methylguanine-DNA methyltransferase (MGMT) methylation status, postoperative radiotherapy, and postoperative temozolomide (TMZ) chemotherapy were independent prognostic factors for OS. MGMT methylation status and subventricular zone (SVZ) involvement were independent prognostic factors for progression-free survival (PFS). A nomogram was constructed based on EOR, ACCI, MGMT methylation status, postoperative radiotherapy and postoperative TMZ chemotherapy to predict the 6-month, 12-month and 18-month OS of older patients with IDH-wild-type GB. The C-index of the nomogram was 0.72, and the ROC curves showed that the areas under the curve (AUCs) at 6, 12 and 18 months were 0.874, 0.739 and 0.779, respectively. The calibration plots showed that the nomogram was in good agreement with the actual observations in predicting the OS of older patients with IDH-wild-type GB. Older patients with IDH-wild-type GB can benefit from gross total resection (GTR), postoperative radiotherapy and postoperative TMZ chemotherapy. A high ACCI score and MGMT nonmethylation are poor prognostic factors. We constructed a nomogram including the ACCI to facilitate clinical decision-making and follow-up interval selection.

A phase Ib/II study of intermittent talazoparib plus temozolomide in patients with metastatic castration-resistant prostate cancer (mCRPC) and no mutations in DNA damage repair (DDR).

e17036 Background: Poly (ADP-ribose) polymerase (PARP) inhibition exhibits an enhanced cytotoxic effect in cancers with DDR alterations, but as monotherapy has little activity for those without DDR defects. A variety of combinatorial methods utilizing PARP inhibitors are under investigation to determine if a multimodal approach could benefit patients without DDR alterations. Supported by pre-clinical models, we hypothesized that the PARP inhibitor talazoparib in combination with the chemotherapy temozolomide could induce DNA damage leading to cell death and tumor response. Methods: This is a single arm Phase 1b/2 study of escalating doses of intermittent talazoparib (Day (D) 1-6) plus temozolomide (D2-8) in 28D cycles in patients with mCRPC without DDR mutations. Patients must have failed at least one androgen receptor signaling inhibitor and may have received chemotherapy in the hormone sensitive setting. Response is determined by a composite endpoint of overall response per RECIST v1.1, PSA50% decline, and CTC conversion from >1 to 0. Pharmacokinetic samples were collected, and the mTPI-2 method was used in escalation. Results: 13 patients were enrolled across 4 dose levels in escalation. The most common adverse events were anemia (any grade (Gr) 31%, Gr3 23%), thrombocytopenia (any Gr 54%, Gr3+ 30.7%), fatigue (Gr≤2, 62%), and nausea (Gr1 46%). There was one patient with a DLT (Gr3 neutropenic fever, Gr4 thrombocytopenia). The identified RP2D was talazoparib 1 mg (D1-6) and temozolomide 75mg/m2 (D2-8). 4 (30.8%) patients met the efficacy endpoint (3 CTC responses, 1 PR, 0 PSA50% decline). While there were no PSA50 responses, 2 (15.4%) patients had a PSA30% decline. Median duration on trial was 20 weeks with 4 (30.8%) patients on trial for ≥6mos, 2 of whom also met the efficacy endpoint. Conclusions: Hematologic toxicity was dose limiting in this combination strategy using intermittent dosing of talazoparib and temozolomide in patients with mCRPC without DDR alterations. A reduction in CTCs to 0 was identified at several dose levels, and PSA30% declines were seen in 2 patients. With identification of the RP2D, enrollment in the Phase 2 study is currently underway. Clinical trial information: NCT04019327 .

Overall survival in patients with recurrent glioblastomas with combination chemotherapy and tumor treating fields (TTF).

e14057 Background: Glioblastoma (GBM) is the most common malignant primary brain tumor with an annual incidence of 3.19 per 100,000 and a very poor prognosis. The median overall survival (OS) is 14.6 to 23 months for clinical trial participants and 11 months for the real-world population. Most GBM recurs in 6 to 9 months and the median OS since recurrence is 3 to 9 months. Despite advancements in clinical trials, there is no uniform standard of care (SOC) for recurrent GBM. We investigated a combination therapy of TTF with temozolomide, bevacizumab, and irinotecan (TBI) chemotherapy at GBM recurrence that improves OS of GBM patients with manageable and reversible side effects. Methods: Retrospective review of medical records of adult GBM patients treated at our institution between 2011 and 2021 showed 500 eligible patients. The primary outcomes were OS and SAE. Statistical analyses utilized the Kaplan-Meier estimate and log-rank tests. Data was compared with published GBM studies. Severe adverse events (SAE) were collected and analyzed by the Common Terminology Criteria for Adverse Events Version 5.0. Results: The 500 patients were separated into three groups based on treatment received at GBM recurrence: TBI+TTF (N = 49), TBI (N = 51) and physician’s choice group (PCG) (N = 400). Median age at diagnosis was 60 (range: 18-87). The median OS from diagnosis was 21, 24.5 and 13 months for TBI+TTF, TBI and PCG, respectively. Among the IDH-1 wild type GBM patients, the median OS was 20, 24 and 13 months for TBI+TTF (N = 42), TBI (N = 47), and PCG (N = 352), respectively. Both demonstrated statistically significant differences among the three groups (HR 0.51, 95% CI 0.33-0.78, p = 0.002) (all patients) and (HR 0.54, 95% CI 0.33-0.90, p = 0.017) (IDH-1 wide type GBM). Other contributing factors that may improve OS include a team of brain tumor treating physicians working together for timely identification of GBM at recurrence and implementation of best treatment accordingly, with combination of modalities, such as stereotactic radiosurgery, salvage radiation, laser ablation, or craniotomy followed by chemotherapy and TTF. Among those that were reviewed, the SAE from TBI-TTF, TBI and PCG groups are grade 3 lymphopenia, (51.0% vs 41.2% vs 31.1%), grade 3 hypertension (26.5% vs. 21.6% vs. 13.1%), and grade 3 leukopenia (10.2% vs. 9.8% vs. 13.1%). An updated SAE count and MGMT promoter methylation survival analyses will be presented at the conference. Conclusions: Compared with published results and PCG, the data suggests that both TBI+TTF and TBI regimens increase OS of GBM patients with manageable and reversible side effects. Optimization of GBM treatments through a collaborative teamwork with all surgical, radiation, and chemotherapy modalities may also contribute to the increased OS. Further research of larger sample sizes and prospective clinical trials are warranted to evaluate the two treatment regimens.

AHR, a novel inhibitory immune checkpoint receptor, is a potential therapeutic target for chemoresistant glioblastoma.

This study aims to elucidate the mechanism underlying temozolomide resistance in patients with MGMT promoter hypomethylated glioblastoma, which is correlated with poor prognosis. The objective is to identify therapeutic targets and drugs suitable for temozolomide-resistant glioblastoma patients using big data analysis. In this retrospective study, transcriptome sequencing data from 457 glioblastoma patients, multi-omics data, and single-cell sequencing data were employed to assess the expression pattern, prognostic value, and biological functions of AHR in glioblastoma. The HERB database was utilized to screen for AHR-targeted drugs for glioblastoma treatment. Validation of our findings was conducted using multiplex immunofluorescence staining of clinical samples and T cells and tumor cells co-culture models. Our findings demonstrated that patients with MGMT promoter unmethylation did not benefit from postoperative temozolomide chemotherapy due to resistance arising from DNA repair function and tumor immune response. AHR was found to be expressed in immune cells and exhibited an immunomodulatory role in glioblastoma with MGMT promoter unmethylation. AHR was identified as a potential novel inhibitory immune checkpoint receptor, serving as a therapeutic target for temozolomide-resistant glioblastoma. Furthermore, targeting AHR with Semen aesculi markedly enhanced the cytotoxic effect of T cells on glioma cells. In addition to DNA repair function, the tumor immune response plays a pivotal role in temozolomide resistance of glioblastoma. Herbal compounds targeting AHR may offer an effective treatment for temozolomide-resistant glioblastoma.

Ribonucleotide reductase regulatory subunit M2 drives glioblastoma TMZ resistance through modulation of dNTP production.

During therapy, adaptations driven by cellular plasticity are partly responsible for driving the inevitable recurrence of glioblastoma (GBM). To investigate plasticity-induced adaptation during standard-of-care chemotherapy temozolomide (TMZ), we performed in vivo single-cell RNA sequencing in patient-derived xenograft (PDX) tumors of GBM before, during, and after therapy. Comparing single-cell transcriptomic patterns identified distinct cellular populations present during TMZ therapy. Of interest was the increased expression of ribonucleotide reductase regulatory subunit M2 (RRM2), which we found to regulate dGTP and dCTP production vital for DNA damage response during TMZ therapy. Furthermore, multidimensional modeling of spatially resolved transcriptomic and metabolomic analysis in patients' tissues revealed strong correlations between RRM2 and dGTP. This supports our data that RRM2 regulates the demand for specific dNTPs during therapy. In addition, treatment with the RRM2 inhibitor 3-AP (Triapine) enhances the efficacy of TMZ therapy in PDX models. We present a previously unidentified understanding of chemoresistance through critical RRM2-mediated nucleotide production.

RYK Gene Expression Associated with Drug Response Variation of Temozolomide and Clinical Outcomes in Glioma Patients.

Temozolomide (TMZ) chemotherapy is an important tool in the treatment of glioma brain tumors. However, variable patient response and chemo-resistance remain exceptionally challenging. Our previous genome-wide association study (GWAS) identified a suggestively significant association of SNP rs4470517 in the RYK (receptor-like kinase) gene with TMZ drug response. Functional validation of RYK using lymphocytes and glioma cell lines resulted in gene expression analysis indicating differences in expression status between genotypes of the cell lines and TMZ dose response. We conducted univariate and multivariate Cox regression analyses using publicly available TCGA and GEO datasets to investigate the impact of RYK gene expression status on glioma patient overall (OS) and progression-free survival (PFS). Our results indicated that in IDH mutant gliomas, RYK expression and tumor grade were significant predictors of survival. In IDH wildtype glioblastomas (GBM), MGMT status was the only significant predictor. Despite this result, we revealed a potential benefit of RYK expression in IDH wildtype GBM patients. We found that a combination of RYK expression and MGMT status could serve as an additional biomarker for improved survival. Overall, our findings suggest that RYK expression may serve as an important prognostic or predictor of TMZ response and survival for glioma patients.

Extensive metastatic ependymoma with long-term progression-free survival with capecitabine plus temozolomide combination chemotherapy: A case report

ABSTRACT We wanted to present a rare case of metastatic grade 2 spinal ependymoma with an atypical course at the time of diagnosis. Temozolomide plus capecitabine chemotherapy was started in May 2018 on a 30-year-old female patient with sacral ependymoma who had extensive lung metastases at the time of diagnosis. The patient remained in remission for approximately 29 months, and the current chemotherapy was continued until it progressed in November 2020. According to this case report, a combination of temozolomide and capecitabine may be the best treatment option for ependymoma patients.

High Expression of Triggering Receptor Expressed on Myeloid Cells 1 Predicts Poor Prognosis in Glioblastoma.

Glioblastoma (GBM) is a highly malignant tumor with poor prognosis, and new treatment strategies are urgently needed. Currently, the role of triggering receptor expressed on myeloid cells 1 (TREM-1) in tumors has been studied, but the role of TREM-1 in GBM remains unclear. Immunohistochemical staining for TREM-1 was performed in 91 patients diagnosed with GBM. Clinicopathological characteristics and survival times were recorded. TREM-1 expression and its effect on prognosis were analyzed using online Gene Expression Profiling Interactive Analysis (GEPIA), The Cancer Genome Atlas (TCGA), and Chinese Glioma Genome Atlas (CGGA) databases. The expression profile of TCGA-GBM cohort was used to perform functional enrichment analysis. The CIBERSORT method and Tumor Immune Estimation Resource (TIMER) database were used to estimate the tumor-infiltrating immune cells (TIICs). The ESTIMATE algorithm was used to estimate the immune-stromal scores. Finally, the relationships of TREM-1 with TIICs, immune-stromal score, and immune checkpoint genes (ICGs) were analyzed. The expression of TREM-1 was upregulated in GBM, and high TREM-1 expression predicted a poor prognosis. TREM-1, surgical resection, postoperative radiotherapy, and temozolomide (TMZ) chemotherapy were associated with the survival time of patients with GBM, but only surgical resection and TREM-1 expression were independent prognostic factors. GBM with high TREM-1 expression exhibited increased neutrophil and macrophage infiltration. TREM-1 was positively associated with the immune-stromal score and multiple ICGs, and most of which were involved in immunosuppressive responses. The present study revealed that high expression of TREM-1 in GBM is an independent poor prognosis factor and that TREM-1 is associated with the immunosuppressive microenvironment. Thus, blocking TREM-1 may be a strategy for enhancing the GBM immune response.

Prognostic Markers in Glioblastoma Patients Treated with Temozolomide (P13-13.002)

<h3>Objective:</h3> To identify biomarkers that are able to predict favorable outcomes for patients with glioblastoma treated with temozolomide (TMZ) <h3>Background:</h3> Glioblastoma is the most aggressive primary brain tumor. The standard of care treatment is maximum safe resection, radiation plus oral temozolomide (TMZ) chemotherapy, followed by six months of cyclic oral TMZ. Treatment-related side effects are common while the 5-year overall survival is less than 10%. Previous studies have reported that TMZ-induced myelosuppression is associated with improved overall survival. <h3>Design/Methods:</h3> Adults with histology-confirmed glioblastoma treated at Beth Israel Deaconess Medical Center from (2017–2018) who had completed both radiation therapy and temozolomide for at least 6 months were identified. Lab values (WBC, ANC, ALC, RBC, PLT), molecular markers (IDH1 R132H, MGMT promoter methylation ), progression free survival (PFS), overall survival (OS) will be collected retrospectively. This data will be combined with published data of 86 cases [Vaios et al.]. <h3>Results:</h3> 60 new patients with glioblastoma were identified and data collected. 32 were included in this study and their data combined with previous data collected from 2012–2017 for a total of 173 patients. Preliminary results according to Kaplan-Meier analysis with a log-rank test confirms that leukopenia is associated with increased survival (p=0.008) and progression free status (p=0.02). <h3>Conclusions:</h3> Decreased white blood cell counts may serve as a peripheral blood biomarker for OS and PFS in glioblastoma patients treated with radiation therapy and TMZ. It is possible that leukopenia reflects adequate temozolomide dosing and anti-tumor activity or reflects changes in the tumor micro-environment. Standardized approaches to peripheral blood monitoring in glioblastoma patients undergoing chemotherapy is likely to improve prognostic stratification and overall survival. <b>Disclosure:</b> Dr. McMillan has nothing to disclose. Dr. Zhang has nothing to disclose. Dr. McGuinness has nothing to disclose. Dr. Trudeau has nothing to disclose. Dr. Uhlmann has nothing to disclose.

TTFields Prolonged the PFS of Epithelioid Glioblastoma Patient: A Case Report

Epithelioid glioblastoma (EGBM, classified as glioblastoma, IDH wild type, grade 4 according to the fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) (WHO CNS5)) is a highly aggressive malignancy, with a median progression-free survival (mPFS) of about 6 months in adults. The application of tumor-treating fields (TTFields, possessing anti-cancer capabilities via anti-mitotic effects) in the maintenance of temozolomide (TMZ) chemotherapy showed a benefit for prolonging the mPFS of newly diagnosed glioblastoma (GBM) for patients for up to 6.9 months in the EF-14 clinical trial (NCT00916409). However, studies focusing on the effect of TTFields in EGBM treatment are very limited due to the rarity of EGBM. Here, we have reported a case of a 28-year-old male (recurrent left-sided limb twitching for 1 month and dizziness for 1 week) diagnosed with EGBM. A right frontal lobe occupancy was detected by magnetic resonance imaging (MRI), and a total tumor resection was performed. Meanwhile, a postoperative histopathology test, including immunohistochemistry and molecular characterization, was conducted, and the results revealed a BRAF V600E mutation, no co-deletion of 1p and 19q, and negative O-6-methylguanine DNA methyltransferase (MGMT) promoter methylation. Then, chemoradiotherapy was conducted, and TTFields and TMZ were performed sequentially. Notably, a long-term PFS of 34 months and a Karnofsky Performance Scale (KPS) of 90 were achieved by the patient on TTFields combined with TMZ, whose average daily usage of TTFields was higher than 90%.

Abstract 5652: IL-19 blockade reprograms glioblastoma immunosuppressive microenvironment and overcomes chemo-resistance as revealed by single-cell transcriptome analyses

Abstract Glioblastoma multiforme (GBM) is the most aggressive brain tumor with chemo-resistant, immunosuppressive, and invasive property. Despite the application of standard therapies which include a combination of surgery, radiotherapy, and temozolomide (TMZ) chemotherapy, tumor inevitably recurred (in patients) at peritumoral region. Targeting multiple arms of the GBM-mediated immunosuppressive ability and their invasiveness can improve therapeutic efficacy. Genomic screening identified that IL-19 is a predicted immune suppressive cytokine in peritumoral region and was associated with poor survival in patients with GBM. IL-19 blockade inhibited both TMZ-sensitive and resistant tumor progression. Molecular studies revealed that silencing IL-19 markedly abrogated IL-19-WISP1-AKT signaling to inhibit TMZ-resistant GBM cell invasion, as well as weaken its suppressive ability on CD8+T cell activation. Single cell transcriptome analysis revealed that IL-19 blockade promoted T cell activation, upregulated effector function of T cell subsets, and reprogrammed tumor-associated macrophage subsets toward a weakened pro-tumoral phenotypes. Thus, Targeting IL-19 can be a novel therapeutic strategy to reverse immunosuppressive microenvironment and restrict invasiveness of chemo-resistant GBM. Citation Format: Gilbert A. Lee, Cheng-Yu Chen. IL-19 blockade reprograms glioblastoma immunosuppressive microenvironment and overcomes chemo-resistance as revealed by single-cell transcriptome analyses. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5652.

Abstract 337: Antitumor effect of oncomagnetic therapy in glioblastoma

Abstract Background: Glioblastoma (GBM) is the most lethal primary malignant brain tumor with a median survival of 15-20 months. Concurrent temozolomide (TMZ) chemotherapy and radiation (XRT) remain the current standard of care (SOC) treatment for newly diagnosed GBM. The addition of tumor treating fields (TTFs) improves median survival from 16 to 20.9 months. This modest improvement underscores the urgent need to identify a new treatment modality as standalone therapy. We have reported recently that brief 2 - 6 h of daily brain stimulation with a new noninvasive, non-contact, magnetic stimulation device causes &amp;gt;30% reduction of contrast-enhanced tumor (CET) volume in an end-stage recurrent GBM patient after a ~30-day treatment. Purpose: The noninvasive Oncomagnetic device developed in our laboratory selectively kills glioblastoma (GBM) and other cancer cells while sparing normal developing neurons and astrocytes in vitro. The spinning oscillating magnetic field (sOMF) generated by this device disrupts electron transport in the mitochondrial respiratory chain leading to a marked increase in reactive oxygen species (ROS) and consequent cancer cell death. However, the downstream molecular mechanism of sOMF action is under investigation. We studied the cellular and molecular effects of sOMF treatment on GBM cell lines and investigated the response to Oncomagnetic monotherapy (OMT) in a syngeneic mouse model. We treated LN229 and U87 GBM cells with sOMF with and without a sub-therapeutic dose of TMZ in vitro. To study the anticancer effect of sOMF in vivo, we developed syngeneic GBM tumors in BALB/c mice by stereotactic intracranial injection of GL261WT cells. Tumor growth was monitored periodically by MRI scans. Results: Our results showed that sOMF significantly reduce cell proliferation and cell survival in vitro. We observed that sOMF induces DNA damage and arrests cells in G1 phase of cell cycle. OMT of tumor-bearing mice using a whole-body sOMF stimulation method caused a substantial retardation of tumor growth and reduction of the contrast-enhanced tumor volume in 9.4 T MRI scans. OMT also showed significant increase in overall survival in these mice. Conclusion: These experiments contribute to unraveling the mechanism of action underlying the response to OMT in GBM and provide a strong rationale for a standalone Oncomagnetic therapy for GBM. Citation Format: Arvind Pandey, Shashank Hambarde, David S. Baskin, Santosh A. Helekar. Antitumor effect of oncomagnetic therapy in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 337.

Abstract 505: Small molecule circadian clock compounds display therapeutic potential in targeting glioblastoma stem cells

Abstract Glioblastoma multiforme (GBM) is the most common primary brain tumor, claiming the lives of roughly 10,000 Americans each year. Despite being the first cancer analyzed through the Cancer Genome Atlas, treatment success remains minimal, resulting average survival time of patients is 15 months following diagnosis and a five-year survival rate is 6.8%. One of the major challenges in treating GBM is the presence of GBM stem cells (GSCs) that are resistant to temozolomide (TMZ) chemotherapy and radiation, which is part of the current standard of care for GBM following maximal surgical resection. We found, however, that GSCs have a unique dependence on core circadian clock proteins, Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK), which is not observed in differentiated GBM cells or normal neuronal stem cells. Here we explore the use of novel small molecule circadian clock compounds that either lower BMAL1 transcription (REV-ERB agonists) or inhibit BMAL1::CLOCK heterodimer transcriptional activity (Cryptochrome (CRY) stabilizers or Casein Kinase (CK) 1/2 inhibitors) in targeting GSCs in in vitro patient derived cell lines and in in vivo GBM patient-derived xenograft (PDX) models. GSCs display increased sensitivity to clock compounds at single agent and combinations of clock compounds compared to non-cancerous cells, U2OS human osteosarcoma cells, and differentiated GSCs. Additionally, clock compounds are significantly more effective in targeting GSCs than TMZ. The clock compound SHP1705 increased over survival and delayed tumor growth in GBM PDX models. These results highlight the therapeutic potential small molecule circadian clock compounds have against GBM as both a single agent and adjuvant to existing therapies by specifically targeting the GSC population. Citation Format: Priscilla Chan, Lian Wu, Anahit Hovsepyan, Seda Mkhitaryan, Gevorg Karapetyan, Khalid Shah, Hiroaki Wakimoto, Theodore Kamenecka, Laura A. Solt, Jamie Cope, Rex A. Moats, Tsuyoshi Hirota, Jeremy N. Rich, Steve A. Kay. Small molecule circadian clock compounds display therapeutic potential in targeting glioblastoma stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 505.

Changes in calpain-2 expression during glioblastoma progression predisposes tumor cells to temozolomide resistance by minimizing DNA damage and p53-dependent apoptosis

BackgroundGlioblastoma multiforme (GBM) is characterized by an unfavorable prognosis for patients affected. During standard-of-care chemotherapy using temozolomide (TMZ), tumors acquire resistance thereby causing tumor recurrence. Thus, deciphering essential molecular pathways causing TMZ resistance are of high therapeutic relevance.MethodsMass spectrometry based proteomics were used to study the GBM proteome. Immunohistochemistry staining of human GBM tissue for either calpain-1 or -2 was performed to locate expression of proteases. In vitro cell based assays were used to measure cell viability and survival of primary patient-derived GBM cells and established GBM cell lines after TMZ ± calpain inhibitor administration. shRNA expression knockdowns of either calpain-1 or calpain-2 were generated to study TMZ sensitivity of the specific subunits. The Comet assay and ɣH2AX signal measurements were performed in order to assess the DNA damage amount and recognition. Finally, quantitative real-time PCR of target proteins was applied to differentiate between transcriptional and post-translational regulation.ResultsCalcium-dependent calpain proteases, in particular calpain-2, are more abundant in glioblastoma compared to normal brain and increased in patient-matched initial and recurrent glioblastomas. On the cellular level, pharmacological calpain inhibition increased the sensitivities of primary glioblastoma cells towards TMZ. A genetic knockdown of calpain-2 in U251 cells led to increased caspase-3 cleavage and sensitivity to neocarzinostatin, which rapidly induces DNA strand breakage. We hypothesize that calpain-2 causes desensitization of tumor cells against TMZ by preventing strong DNA damage and subsequent apoptosis via post-translational TP53 inhibition. Indeed, proteomic comparison of U251 control vs. U251 calpain-2 knockdown cells highlights perturbed levels of numerous proteins involved in DNA damage response and downstream pathways affecting TP53 and NF-κB signaling. TP53 showed increased protein abundance, but no transcriptional regulation.ConclusionTMZ-induced cell death in the presence of calpain-2 expression appears to favor DNA repair and promote cell survival. We conclude from our experiments that calpain-2 expression represents a proteomic mode that is associated with higher resistance via “priming” GBM cells to TMZ chemotherapy. Thus, calpain-2 could serve as a prognostic factor for GBM outcome.

Progress in phase III clinical trials of molecular targeted therapy and immunotherapy for glioblastoma.

Glioblastoma (GBM) is the most common primary central nervous system tumor, whose prognosis remains poor under the sequential standard of care, such as neurosurgery followed by concurrent temozolomide radiochemotherapy and adjuvant temozolomide chemotherapy in the presence or absence of tumor treating fields. Accordingly, the advent of molecular targeted therapy and immunotherapy has opened a new era of tumor management. A diverse range of targeted drugs have been tested in patients with GBM in phase III clinical trials. However, these drugs are ineffective for all patients, as evidenced by the fact that only a minority of patients in these trials showed prolonged survival. Furthermore, there are several published phase III clinical trials that involve immune checkpoint inhibitors, peptide vaccines, dendritic cell vaccines, and virotherapy. Accordingly, this review comprehensively overviews existing studies of targeted drugs and immunotherapy for glioma and discusses the challenge and perspective of targeted drugs and immunotherapy for glioma to clarify future directions.

Simulated Adaptive Radiotherapy for Shrinking Glioblastoma Resection Cavities on a Hybrid MRI-Linear Accelerator.

During radiation therapy (RT) of glioblastoma, daily MRI with combination MRI-linear accelerator (MRI-Linac) systems has demonstrated significant anatomic changes, including evolving post-surgical cavity shrinkage. Cognitive function RT for brain tumors is correlated with radiation doses to healthy brain structures, especially the hippocampi. Therefore, this study investigates whether adaptive planning to the shrinking target could reduce normal brain RT dose with the goal of improving post-RT function. We evaluated 10 glioblastoma patients previously treated on a 0.35T MRI-Linac with a prescription of 60 Gy delivered in 30 fractions over six weeks without adaptation ("static plan") with concurrent temozolomide chemotherapy. Six weekly plans were created per patient. Reductions in the radiation dose to uninvolved hippocampi (maximum and mean) and brain (mean) were observed for weekly adaptive plans. The dose (Gy) to the hippocampi for static vs. weekly adaptive plans were, respectively: max 21 ± 13.7 vs. 15.2 ± 8.2 (p = 0.003) and mean 12.5 ± 6.7 vs. 8.4 ± 4.0 (p = 0.036). The mean brain dose was 20.6 ± 6.0 for static planning vs. 18.7 ± 6.8 for weekly adaptive planning (p = 0.005). Weekly adaptive re-planning has the potential to spare the brain and hippocampi from high-dose radiation, possibly reducing the neurocognitive side effects of RT for eligible patients.

Deep learning MRI signature to predict survival and treatment benefit from temozolomide in IDH-wildtype glioblastoma

BackgroundO6-methylguanine-DNA-methyltransferase (MGMT) methylation status does not correlate with temozolomide (TMZ) sensitivity in all IDH-wildtype glioblastoma (GBM) patients. New predictors of TMZ benefit are still in demand. MethodsBased on MR images, a deep learning image signature was constructed to predict the survival and benefit of temozolomide in patients with IDH wild-type glioblastoma. ResultsDiS signature was associated with OS as an independent prognostic factor in patients with IDH-wildtype glioblastoma. For high-risk group patients, TMZ was associated with improved OS for patients in MGMT-methylated subgroup (HR: 2.051, 95 % CI: 0.939–4.482, log-rank P = 0.034), but had not effect on MGMT-unmethylated patients. However, patients in the low- risk group did not benefit from TMZ. ConclusionDiS could offer complementary value beyond MGMT methylation status in predicting survival benefit from TMZ chemotherapy in patients with IDH-wildtype glioblastoma.

Glioblastoma modeling with 3D organoids: progress and challenges.

Glioblastoma (GBM) is the most aggressive adult primary brain tumor with nearly universal treatment resistance and recurrence. The mainstay of therapy remains maximal safe surgical resection followed by concurrent radiation therapy and temozolomide chemotherapy. Despite intensive investigation, alternative treatment options, such as immunotherapy or targeted molecular therapy, have yielded limited success to achieve long-term remission. This difficulty is partly due to the lack of pre-clinical models that fully recapitulate the intratumoral and intertumoral heterogeneity of GBM and the complex tumor microenvironment. Recently, GBM 3D organoids originating from resected patient tumors, genetic manipulation of induced pluripotent stem cell (iPSC)-derived brain organoids and bio-printing or fusion with non-malignant tissues have emerged as novel culture systems to portray the biology of GBM. Here, we highlight several methodologies for generating GBM organoids and discuss insights gained using such organoid models compared to classic modeling approaches using cell lines and xenografts. We also outline limitations of current GBM 3D organoids, most notably the difficulty retaining the tumor microenvironment, and discuss current efforts for improvements. Finally, we propose potential applications of organoid models for a deeper mechanistic understanding of GBM and therapeutic development.

Adjuvant Temozolomide Chemotherapy With or Without Interferon Alfa Among Patients With Newly Diagnosed High-grade Gliomas

High-grade gliomas (HGGs) constitute the most common and aggressive primary brain tumor, with 5-year survival rates of 30.9% for grade 3 gliomas and 6.6% for grade 4 gliomas. The add-on efficacy of interferon alfa is unclear for the treatment of HGG. To compare the therapeutic efficacy and toxic effects of the combination of temozolomide and interferon alfa and temozolomide alone in patients with newly diagnosed HGG. This multicenter, randomized, phase 3 clinical trial enrolled 199 patients with newly diagnosed HGG from May 1, 2012, to March 30, 2016, at 15 Chinese medical centers. Follow-up was completed July 31, 2021, and data were analyzed from September 13 to November 24, 2021. Eligible patients were aged 18 to 75 years with newly diagnosed and histologically confirmed HGG and had received no prior chemotherapy, radiotherapy, or immunotherapy for their HGG. All patients received standard radiotherapy concurrent with temozolomide. After a 4-week break, patients in the temozolomide with interferon alfa group received standard temozolomide combined with interferon alfa every 28 days. Patients in the temozolomide group received standard temozolomide. The primary end point was 2-year overall survival (OS). Secondary end points were 2-year progression-free survival (PFS) and treatment tolerability. A total of 199 patients with HGG were enrolled, with a median follow-up time of 66.0 (95% CI, 59.1-72.9) months. Seventy-nine patients (39.7%) were women and 120 (60.3%) were men, with ages ranging from 18 to 75 years and a median age of 46.9 (95% CI, 45.3-48.7) years. The median OS of patients in the temozolomide plus interferon alfa group (26.7 [95% CI, 21.6-31.7] months) was significantly longer than that in the standard group (18.8 [95% CI, 16.9-20.7] months; hazard ratio [HR], 0.64 [95% CI, 0.47-0.88]; P = .005). Temozolomide plus interferon alfa also significantly improved median OS in patients with O6-methylguanine-DNA methyltransferase (MGMT) unmethylation (24.7 [95% CI, 20.5-28.8] months) compared with temozolomide (17.4 [95% CI, 14.1-20.7] months; HR, 0.57 [95% CI, 0.37-0.87]; P = .008). Seizure and influenzalike symptoms were more common in the temozolomide plus interferon alfa group, with 2 of 100 (2.0%) and 5 of 100 (5.0%) patients with grades 1 and 2 toxic effects, respectively (P = .02). Finally, results suggested that methylation level at the IFNAR1/2 promoter was a marker of sensitivity to temozolomide plus interferon alfa. Compared with the standard regimen, temozolomide plus interferon alfa treatment could prolong the survival time of patients with HGG, especially the MGMT promoter unmethylation variant, and the toxic effects remained tolerable. ClinicalTrials.gov Identifier: NCT01765088.