Glioblastoma Multiforme Tumor Cells Research Articles

Therapeutic modulation of APP-CD74 axis can activate phagocytosis of TAMs in GBM

Glioblastoma multiforme (GBM) remains the most lethal central nervous system cancer with poor survival and few targeted therapies. The GBM tumor microenvironment is complex and closely associated with outcomes. Here, we analyzed the cell-cell communication within the microenvironment and found the high level of cell communication between GBM tumor cells and tumor-associated macrophages (TAMs). We found that the amyloid protein precursor (APP)-CD74 axis displayed the highest levels of communication between GBM tumor cells and TAMs, and that APP and CD74 expression levels were significantly corelated with poorer patient outcomes. We showed that the expression of APP on the surface of GBM inhibited phagocytosis of TAMs through the binding of APP to the CD74/CXCR4 cell surface receptor complex. We further demonstrated that disrupting the APP-CD74 axis could upregulated the phagocytosis of TAMs in vitro and in vivo. Finally, we demonstrated that APP promotes the phosphorylation of SHP-1 by binding to CD74. Together, our findings revealed that the APP-CD74 axis was a highly expressed anti-phagocytic signaling pathway that may be a potential immunotherapeutic target for GBM.

Transduction Efficiency of Zika Virus E Protein Pseudotyped HIV-1gfp and Its Oncolytic Activity Tested in Primary Glioblastoma Cell Cultures.

The development of new tools against glioblastoma multiforme (GBM), the most aggressive and common cancer originating in the brain, remains of utmost importance. Lentiviral vectors (LVs) are among the tools of future concepts, and pseudotyping offers the possibility of tailoring LVs to efficiently transduce and inactivate GBM tumor cells. Zika virus (ZIKV) has a specificity for GBM cells, leaving healthy brain cells unharmed, which makes it a prime candidate for the development of LVs with a ZIKV coat. Here, primary GBM cell cultures were transduced with different LVs encased with ZIKV envelope variants. LVs were generated by using the pNLgfpAM plasmid, which produces the lentiviral, HIV-1-based, core particle with GFP (green fluorescent protein) as a reporter (HIVgfp). Using five different GBM primary cell cultures and three laboratory-adapted GBM cell lines, we showed that ZIKV/HIVgfp achieved a 4-6 times higher transduction efficiency compared to the commonly used VSV/HIVgfp. Transduced GBM cell cultures were monitored over a period of 9 days to identify GFP+ cells to study the oncolytic effect due to ZIKV/HIVgfp entry. Tests of GBM tumor specificity by transduction of GBM tumor and normal brain cells showed a high specificity for GBM cells.

Targeted Glioma Therapy-Clinical Trials and Future Directions.

Glioblastoma multiforme (GBM) is the most common type of glioma, with a median survival of 14.6 months post-diagnosis. Understanding the molecular profile of such tumors allowed the development of specific targeted therapies toward GBM, with a major role attributed to tyrosine kinase receptor inhibitors and immune checkpoint inhibitors. Targeted therapeutics are drugs that work by specific binding to GBM-specific or overexpressed markers on the tumor cellular surface and therefore contain a recognition moiety linked to a cytotoxic agent, which produces an antiproliferative effect. In this review, we have summarized the available information on the targeted therapeutics used in clinical trials of GBM and summarized current obstacles and advances in targeted therapy concerning specific targets present in GBM tumor cells, outlined efficacy endpoints for major classes of investigational drugs, and discussed promising strategies towards an increase in drug efficacy in GBM.

Effect of folic acid-linked chitosan-coated PLGA-based curcumin nanoparticles on the redox system of glioblastoma cancer cells.

Oxidative stress is one of the carcinogenic mechanisms underlying the development of glioblastoma multiforme (GBM), a highly aggressive brain tumor type associated with poor prognosis. Curcumin is known to be an efficient antioxidant, anti-inflammatory, and anticancer compound. However, its poor solubility in water, inappropriate pharmacokinetics, and low bioavailability limit its use as an antitumor drug. We prepared PLGA-based curcumin nanoparticles changed with folic acid and chitosan (curcumin-PLGA-CS-FA) and evaluated its effects on GBM tumor cells' redox status. The nanoprecipitation method was used to synthesize CU nanoparticles (CU-NPs). The size, morphology, and stability were characterized by DLS, SEM, and zeta potential analysis, respectively. The CU-NPs' toxic properties were studied by MTT assay and measuring the intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations. The study was completed by measuring the gene expression levels and activity of superoxide dismutase, catalase, glutaredoxin, and thioredoxin antioxidant enzymes. The size, polydispersity index, and zeta potential of CU-NPs were 77.27 nm, 0.29, and -22.45 mV, respectively. The encapsulation efficiency was approximately 98%. Intracellular ROS and MDA levels decreased after CU-NP treatment. Meanwhile, the CU-NPs increased gene expression and activity of superoxide dismutase, catalase, glutaredoxin, and thioredoxin antioxidant enzymes. CU-NPs might be effective in the prevention and treatment of glioblastoma cancer by modulating the antioxidant-oxidant balance.

Nucleic acid immunotherapeutics and vaccines: A promising approach to glioblastoma multiforme treatment

Glioblastoma multiforme (GBM) is a deadly and difficult to treat primary brain tumor for which satisfactory therapeutics have yet to be discovered. While cancer immunotherapeutics, such as immune checkpoint inhibitors, have successfully improved the treatment of some other types of cancer, the poorly immunogenic GBM tumor cells and the immunosuppressive GBM tumor microenvironment have made it difficult to develop GBM immunotherapeutics. Nucleic acids therapeutics and vaccines, particularly those of mRNA, have become a popular field of research in recent years. This review presents the progress of nucleic acid therapeutics and vaccines for GBM and briefly covers some representative delivery methods of nucleic acids to the central nervous system (CNS) for GBM therapy.

Targeted Sensitization of Glioblastoma Multiforme Using AAAPT Technology.

Glioblastoma Multiforme (GBM) is the most malignant type of all brain tumors. Current GBM treatment options include surgery, followed by radiation and chemotherapy. However, GBM can become resistant to therapy, resulting in tumor recurrence. GBM cells develop resistance to treatments by either downregulating cell death pathways (CD95) or upregulating cell survival pathways (NF-κB (p65)). Healthy tissues can be affected by the increased therapeutic dose. Therefore, it is important to develop a method that can only target GBM tumor cells, thereby reducing the non-specific uptake which will reduce the side effects. Here we demonstrate an application of novel priori activation of apoptosis pathways of tumor technology (AAAPT), which has been used to demonstrate the effect of targeted tumor sensitizers to make chemotherapy work at lower doses in breast, lung and prostate cancers. Treatment of GBM spheroids with AAAPT in 3D PEGDA microwells, showed an increase in cell death, an upregulation of cell death pathways, and a downregulation of cell survival pathways, in comparison to Temozolomide (TMZ), an oral alkylating agent, which is a commonly used chemotherapy in the treatment of GBM. The dose of AAAPT sensitizers may provide a promising method to increase treatment efficacy and reduce off-target toxicity, as an alternative to existing methods which cause significant off-target damage.

NIR-II absorptive dithienopyrrole-thiadiazolobenzotriazole conjugated polymer for photoacoustic imaging-guided glioblastoma multiforme photothermal therapy

The development of new diagnostic imaging and precise treatment methods for glioblastoma multiforme (GBM) is significant to improve patients' quality of life and prolong their survival time. Herein, we proposed a photoacoustic imaging (PAI)-guided GBM high-efficient photothermal therapy (PTT) based on a second near-infrared (NIR-II) absorptive polymer (PDTP-TBZ) conjugated with intense electron donor dithienopyrrole (DTP) and strong electron acceptor thiadiazolobenzotriazole (TBZ). By nanoprecipitation, PDTP-TBZ can form into nanoparticles (PT NPs), and c(RGDfK) cyclic peptide with integrin-specific targeting was then modified on the surface of PT NPs to obtain the ability of active targeting GBM multifunctional nano-reagent (cRGD@PT NPs). Both in vitro and in vivo experiments demonstrated that cRGD@PT NPs as NIR-II GBM phototheranostic reagents can greatly improve the enrichment rate at tumor sites under PAI monitoring, and carry out precise NIR-II PTT with high effective tumor cell phototoxicity and high biological safety. Thus, cRGD@PT NPs have great potential for the future GBM phototheranostic application in clinic. Statement of significanceIn this work, we successfully constructed an intense electron donor dithienopyrrole (DTP) with a strong electron acceptor thiadiazolobenzotriazole (TBZ) into a novel NIR-II optical absorptive conjugated polymer (PDTP-TBZ). Then, the c(RGDfK) cyclic peptide was modified on the surface of PT NPs to obtain multifunctional nanodiagnostic reagents (cRGD@PT NPs) that can effectively target GBM neovascularization and tumor cells. Both in vitro and in vivo experiments demonstrate that cRGD@PT NPs possess high photothermal conversion efficiency and practical photoacoustic imaging capability under 1064 nm laser irradiation. The results of this work suggested that cRGD@PT NPs have great potential in efficient NIR-II PTT guided by accurate PAI, which provide a good perspective for the treatment and diagnosis of GBM.

Isolinderalactone inhibits glioblastoma cell supernatant-induced angiogenesis.

Glioblastoma multiforme (GBM) is the most frequently occurring malignant brain tumor in adults and is characterized by a high degree of vascularization. Glioblastoma cells communicate with their microenvironment and stimulate blood vessel formation to support tumor progression. It has previously been reported that isolinderalactone induces apoptosis in GBM cells and suppresses the growth of glioblastoma xenograft tumors in vivo. Furthermore, isolinderalactone has been shown to inhibit the hypoxia-driven upregulation of vascular endothelial growth factor (VEGF) in U-87 GBM cells and strongly reduce VEGF-triggered angiogenesis in vitro and in vivo. In the present study, the direct angiogenic effect of GBM and the effect of isolinderalactone on tumor angiogenesis were investigated. Culture supernatants were obtained from U-87 cells under normoxic or hypoxic conditions to provide normoxic conditioned medium (NCM) and hypoxic conditioned medium (HCM) respectively. The NCM and HCM were each used to treat to human brain microvascular endothelial cells (HBMECs), and their effects were observed using wounding migration and tube formation assays. HCM increased the migration and capillary-like tube formation of HBMECs when compared with NCM, and treatment with isolinderalactone suppressed the HCM-driven angiogenesis in vitro. Additionally, isolinderalactone decreased HCM-triggered angiogenic sprouting in HBMECs in a 3D microfluidic device after the application of an HCM-containing interstitial fluid flow. Furthermore, isolinderalactone strongly reduced HCM-triggered angiogenesis in an in vivo Matrigel plug assay in mice. These findings provide evidence of angiogenesis inhibition by isolinderalactone, and demonstrate the anti-angiogenic effect of isolinderalactone against the direct angiogenic effect of GBM tumor cells.

Selected Articles from This Issue

Glioblastoma multiforme (GBM) is a highly aggressive cancer characterized by drug resistance and invasion. While it has been recognized that gap junctions (GJ) between GBM tumor cells and adjacent astrocytes are important for GBM invasion, the molecular mechanisms by which GJ contribute to GBM cell invasion have yet to be described. In their study, McCutcheon and Spray query the role of GJ protein Connexin 43 (Cx43) in GBM cell invasion via Cx43 genetic ablation and pharmacological inhibition in GBM cell line-astrocyte co-cultures and ex vivo brain organotypic slice cultures. The authors reveal a dichotomous function of Cx43 in GBM cell invasion, where Cx43 inhibition in GBM cells enhances GBM cell invasion and Cx43 inhibition in astrocytes abrogates GBM cell invasion. Transcriptomics analysis implicated miR-19b in the mechanism underlying the role of Cx43 in GBM cell invasion, an implication that was confirmed both in vitro and ex vivo. Overall, the study unveils a previously unknown mechanism governing GBM cell invasion that could inform targeted GBM therapeutic strategies moving forward.While dysregulated Notch signaling has been implicated in multiple cancer types, the role(s) of MIB1, an E3 ubiquitin ligase that is key for Notch signaling, in cancer has yet to be defined. Wang and colleagues show that MIB1 expression is increased in some lung squamous carcinomas and lung adenocarcinomas relative to adjacent healthy tissues, and that elevated MIB1 expression correlates with poor patient survival. Using a stably transduced MIB1 overexpressing cell line, the authors demonstrate that MIB1 can induce epithelial–mesenchymal transition and tumor cell motility. Conversely, eliminating MIB1 via CRISPR/Cas9 induced a more epithelial phenotyp. characterized by reduced tumor cell motility. The authors also find that MIB1 renders lung cancer cells susceptible to death induced by glutathione peroxidase 4 inhibitor RSL3, suggesting MIB1 expression sensitizes tumor cells to ferroptosis. Correspondingly, the authors show that MIB1 ubiquitinates master antioxidant transcription factor NRF2, allowing lipid peroxide accumulation and subsequent ferroptosis. Altogether, the data presented elucidate how MIB1 can contribute to tumorigenesis and suggest that patients bearing tumors with elevated MIB1 expression may benefit from treatment with ferroptosis-inducing agents.FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutations are prevalent in acute myeloid leukemia (AML) and are associated with poor prognoses. Existing FLT3 inhibitors can induce drug resistance and lose efficacy against AML, making combinatorial therapeutic approaches against FLT3-ITD–mutant AML an area of interest. By querying transcriptomes of FLT3-ITD–mutant AML cell lines treated with FLT3 inhibitors, Zhang and colleagues observed that FLT3-ITD mutations correlate with increased expression of de novo creatine biosynthesis pathway components. Accordingly, the authors found that FLT3-ITD–mutant AML cells contain heightened levels of creatine and ATP. The authors discovered that FLT3-ITD mutations increase de novo creatine biosynthesis in part via STAT5-mediated transcription of glycine amidinotransferase (AGAT), a critical enzyme in the creatine biosynthetic pathway. A creatine analog and shRNA-mediated AGAT ablation increased FLT3-ITD–mutant AML cell apoptosis and decreased proliferation, and each approach synergized with FLT3 inhibition to impede AML cell proliferation and survival in vitro. Overall, the study elucidates a previously unknown mechanism by which FLT3-ITD mutations promote AML and provides a new therapeutic target for patients with AML harboring FLT3-ITD mutations.Human papillomaviruses (HPV) are causally linked to several cancers, but molecular host–pathogen interactions underlying oncogenesis have not been fully elucidated. In their study, Mirza and colleagues show that Ecdysoneless (ECD), the human homolog of the Drosophila ecdysoneless gene, is highly expressed in head and neck squamous cell carcinoma cell lines as well as cervical cancer cell lines and tumor samples. Using in vitro protein–protein binding and cellular immunoprecipitation assays, the authors demonstrate that ECD binds to high-risk HPV E6 oncoprotein. Ablating ECD expression using siRNA revealed that ECD participates in E6 RNA splicing, as well as splicing of cellular mRNA encoding proteins that are critical for HPV-driven oncogenesis. Disruption of ECD expression also abrogated cervical cancer cell line colony formation, migration, and invasion, further supporting the finding that ECD contributes to HPV-driven oncogenesis. Taken together, the presented data further clarify molecular HPV-host interactions underlying HPV-driven oncogenesis and provide a potential novel therapeutic target for HPV-positive cancers.

CircRNA derived from CLSPN (circCLSPN) is an oncogene in human glioblastoma multiforme by regulating cell growth, migration and invasion via ceRNA pathway

Glioblastoma multiforme (GBM) is the most aggressive and prevalent brain tumor in adults. The circRNA derived from CLSPN (hsa_circ_0011591, circCLSPN) is remarkably upregulated in GBM; however its functional role was uncovered yet. First, we examined expression of circCLSPN using GSE109569 database and RT-qPCR, and circCLSPN level was upregulated in human GBM tumor tissues and cells (A172 and LN18); moreover, circCLSPN showed a stable structure stability. Then, a series of loss-of-functional experiments were performed using CCK-8 assay, colony formation assay, flow cytometry, scratch wound assay, and transwell assay. Consequently, circCLSPN silencing suppressed cell viability, colony formation ability, cell cycle progression, migration, and invasion of A172 and LN18 cells in vitro, and promoted apoptosis rate. Allied with those were decreased B cell lymphoma-2 (Bcl-2), matrix metalloproteinase-2 (MMP2) and MMP9 expression, and elevated Bcl-2-associated X protein (Bax) level. According to dual-luciferase reporter assay and RNA pull-down assay, miR-370-3p was identified to be targeted and sponged by circCLSPN, and further targeted and negatively regulated USP39. Functionally, overexpressing miR-370-3p could mimic in vitro effects of circCLSPN interference. Rescue experiments revealed that blocking miR-370-3p could partially reverse the suppression of circCLSPN knockdown on cell growth, migration and invasion, and role of miR- 370-3p overexpression was abrogated by restoring USP39. In vivo, circCLSPN knockdown hindered tumor growth of LN18 cells by affecting miR-370-3p, USP39, MMP2 and MMP9 expression. In conclusion, circCLSPN elicited an oncogenic role in tumorigenesis and malignant progression of human GBM cells through circCLSPN-miR-370-3p-USP39 pathway.

Combinatorial immunotherapy of N-803 (IL-15 superagonist) and dinutuximab with ex vivo expanded natural killer cells significantly enhances in vitro cytotoxicity against GD2+ pediatric solid tumors and in vivo survival of xenografted immunodeficient NSG mice

BackgroundChildren with recurrent and/or metastatic osteosarcoma (OS), neuroblastoma (NB) and glioblastoma multiforme (GBM) have a dismal event-free survival (<25%). The majority of these solid tumors highly express GD2. Dinutuximab, an...

Human Cytomegalovirus Genomes Survive Mitosis via the IE19 Chromatin-Tethering Domain.

The genomes of DNA tumor viruses regain nuclear localization after nuclear envelope breakdown during mitosis through the action of a viral protein with a chromatin-tethering domain (CTD). Here, we report that the human cytomegalovirus (HCMV) genome is maintained during mitosis by the CTD of the viral IE19 protein. Deletion of the IE19 CTD or disruption of the IE19 splice acceptor site reduced viral genome maintenance and progeny virion formation during infection of dividing fibroblasts, both of which were rescued by IE19 ectopic expression. The discovery of a viral genome maintenance factor during productive infection provides new insight into the mode of HCMV infection implicated in birth defects, organ transplant failure, and cancer.IMPORTANCE Human cytomegalovirus (HCMV) is the leading infectious cause of birth defects, represents a serious complication for immunocompromised HIV/AIDS and organ transplant patients, and contributes to both immunosenescence and cardiovascular diseases. HCMV is also implicated in cancers such as glioblastoma multiforme (GBM) and infects ex vivo-cultured GBM tumor cells. In dividing tumor cells, the genomes of DNA tumor viruses regain nuclear localization after nuclear envelope breakdown during mitosis. This mitotic survival is mediated by a viral protein with a chromatin-tethering domain (CTD). Here, we report that the HCMV genome is maintained in dividing fibroblasts by the CTD of the viral IE19 protein. The discovery of a viral genome maintenance factor during productive infection could help explain viral genome dynamics within HCMV-positive tumors as well as during latency.

CDC6 is up-regulated and a poor prognostic signature in glioblastoma multiforme.

Glioblastoma multiforme (GBM) represents the most common and the most malignant type of brain tumor. Cell division cycle 6 (CDC6), a gene associated with DNA replication initiation, has been proven to be associated with the prognosis of multiple tumors. In this study, we aim to explore the association between CDC6 expression and GBM carcinogenesis and prognosis. CDC6 expression in normal cells and GBM cells was explored by analyzing TCGA dataset, as well as by RT-PCR and western blot methods. Survival analysis was performed by the Kaplan-Meier method. Multivariate Cox-regression analysis was adopted to estimate the independence of CDC6 as a GBM prognostic factor. Elevated CDC6 levels in GBM tumor tissues compared with those in normal brain tissues were illustrated by analyzing the gene expression profiles from TCGA dataset, and confirmed by RT-PCR and western blot assays in GBM tumor and normal human astrocyte cell lines. Kaplan-Meier analysis indicated the negative influence of high CDC6 expression on GBM overall survival (OS) probability and days to progression (D2P) after initial treatment, but not on days to recurrence (D2R) after initial treatment. Multivariate Cox regression analysis showed CDC6 as an independent signature marker gene for GBM prognosis. In addition, the combination of CDC6 mRNA expression and CpG island methylator phenotype (CIMP) could sensitively predict 3-year OS and D2P. In conclusion, our study uncovered the role of CDC6 in GBM carcinogenesis and prognosis for the first time, which could shed new light on GBM diagnosis and treatment.

Inhibition of miR-1193 leads to synthetic lethality in glioblastoma multiforme cells deficient of DNA-PKcs

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor and has the highest mortality rate among cancers and high resistance to radiation and cytotoxic chemotherapy. Although some targeted therapies can partially inhibit oncogenic mutation-driven proliferation of GBM cells, therapies harnessing synthetic lethality are ‘coincidental’ treatments with high effectiveness in cancers with gene mutations, such as GBM, which frequently exhibits DNA-PKcs mutation. By implementing a highly efficient high-throughput screening (HTS) platform using an in-house-constructed genome-wide human microRNA inhibitor library, we demonstrated that miR-1193 inhibition sensitized GBM tumor cells with DNA-PKcs deficiency. Furthermore, we found that miR-1193 directly targets YY1AP1, leading to subsequent inhibition of FEN1, an important factor in DNA damage repair. Inhibition of miR-1193 resulted in accumulation of DNA double-strand breaks and thus increased genomic instability. RPA-coated ssDNA structures enhanced ATR checkpoint kinase activity, subsequently activating the CHK1/p53/apoptosis axis. These data provide a preclinical theory for the application of miR-1193 inhibition as a potential synthetic lethal approach targeting GBM cancer cells with DNA-PKcs deficiency.

HSP70/IL-2 Treated NK Cells Effectively Cross the Blood Brain Barrier and Target Tumor Cells in a Rat Model of Induced Glioblastoma Multiforme (GBM).

Natural killer (NK) cell therapy is one of the most promising treatments for Glioblastoma Multiforme (GBM). However, this emerging technology is limited by the availability of sufficient numbers of fully functional cells. Here, we investigated the efficacy of NK cells that were expanded and treated by interleukin-2 (IL-2) and heat shock protein 70 (HSP70), both in vitro and in vivo. Proliferation and cytotoxicity assays were used to assess the functionality of NK cells in vitro, after which treated and naïve NK cells were administrated intracranially and systemically to compare the potential antitumor activities in our in vivo rat GBM models. In vitro assays provided strong evidence of NK cell efficacy against C6 tumor cells. In vivo tracking of NK cells showed efficient homing around and within the tumor site. Furthermore, significant amelioration of the tumor in rats treated with HSP70/Il-2-treated NK cells as compared to those subjected to nontreated NK cells, as confirmed by MRI, proved the efficacy of adoptive NK cell therapy. Moreover, results obtained with systemic injection confirmed migration of activated NK cells over the blood brain barrier and subsequent targeting of GBM tumor cells. Our data suggest that administration of HSP70/Il-2-treated NK cells may be a promising therapeutic approach to be considered in the treatment of GBM.

CBMT-38. THERAPEUTIC INHIBITION OF THE SPLICEOSOME IN GLIOBLASTOMA: CHANGES FORM MINOR TO MAJOR

Abstract Chemical or genetic perturbation of the spliceosome function may represent a therapeutic opportunity for Glioblastoma multiforme (GBM) and other cancers. We and others have shown that oncogenic MYC activity causes spliceosome vulnerability and leads to deficits in 3’ splice site recognition upon spliceosome perturbation. Several spliceosome inhibitors in pre-clinical development and in clinical trials target the U2 snRNP subcomplex SF3B, which is essential for 3’ splice site recognition. We showed that knockdown of one of its subunits, PHF5A, causes GBM-specific changes in splicing, including increases in exon skipping, intron retention and activation of alternative 3’ and 5’ splice sites. However, in depth analysis of these events revealed they are disproportionately enriched for “minor” introns. This class of ~800 introns is specifically excised by an alternative splicing pathway which involves the U12-dependent spliceosome. Remarkably, we provide evidence that inhibition of PHF5A in GBM stem-like cells causes increased retention of most minor introns, as well as activation of cryptic and alternative U2 snRNP-dependent splicing sites. We further demonstrate that components of the U12 snRNP complex are differentially required for GSC-specific viability. Our results suggest that regulation of the splicing of U12-type introns may be critically important for GBM tumor cell viability.

P.020 Avelumab in newly diagnosed glioblastoma multiforme-the SEJ study

Background: Glioblastoma Multiforme (GBM) has well documented systemic and local immunosuppressive mechanisms to escape immune surveillance and grow. GBM tumor cells as well as the microglia within it have a high incidence of PD-L1 surface expression which makes it more susceptible to anti-PD-L1 antagonism and ADCC through avelumab therapy. Methods: This is a single center, phase 2, open label, add-on, single dose study of 156 weeks duration in patients receiving standard therapy for newly diagnosed GBM. In total 30 patients will be entered into the study within 3 weeks of finishing their last day of combined radiotherapy/temozolomide. The following are the results of the first interim analysis completed when the first eight patients completed 52 weeks or an end of study visit. Results: 24 patients have so far started therapy. There as been no unexpected treatment emergent adverse event (TEAE). Two patients transiently withheld therapy because of immune related TEAE’s and none permanently. The objective response rate at week 52 for the first eight patients was 50% with 2 (25%) having a complete response and 1 (12.5%) a partial response. Conclusions: These preliminary results suggest that the addition of avelumab to standard therapy in patients with GBM is safe. Efficacy trends look promising.

Avelumab in newly diagnosed glioblastoma multiforme: The SEJ study.

e13571 Background: Glioblastoma Multiforme (GBM) has well documented systemic and local immunosuppressive mechanisms to escape immune surveillance and grow. GBM tumor cells as well as the microglia within it have a high PD-L1 surface expression which may make it susceptible to anti-PD-L1 antagonism and ADCC with avelumab therapy. Standard combination temozolomide/radiotherapy is associated with a median survival of 14.6 months and a median progression free survival of 6.9 months. Methods: This is a single center, phase 2, open label study of avelumab 10 mg/kg Q2W for 156 weeks duration in patients receiving standard therapy for newly diagnosed GBM. Thirty patients will be entered into the study within 3 weeks of completing combined radiotherapy/temozolomide. Here, we report the results of the first interim analysis completed when the first eight patients completed 52 weeks or an end of study visit. Results: To date 24 patients have started therapy. The median follow-up is 4.9 months (1-22 months). There has been overall no unexpected treatment emergent adverse event (TEAE). The most common TEAE was elevated liver or pancreatic enzymes. Two patients transiently withheld therapy because of immune related TEAE’s (both hepatitis) and none permanently. The objective response rate by iRANO criteria, at week 52 for the first eight patients was 4 (50%) with 2 (25%) having a complete response, 1 (12.5%) a partial response and 1 (12.5%) stable disease. The median progression free survival was 11.9 months. Conclusions: These preliminary results suggest that the addition of avelumab to standard combination therapy early on, in patients with GBM is safe. Efficacy trends look promising. Clinical trial information: NCT03047473.

Evidence of Aquaporin 4 Regulation by Thyroid Hormone During Mouse Brain Development and in Cultured Human Glioblastoma Multiforme Cells.

Accumulating evidence indicates that thyroid function and the thyroid hormones L-thyroxine (T4) and L-triiodothyronine (T3) are important factors contributing to the improvement of various pathologies of the central nervous system, including stroke, and various types of cancer, including glioblastoma multiforme (GBM). Low levels of T3 are correlated with the poorest outcome of post-stroke brain function, as well as an increased migration and proliferation of GBM tumor cells. Thyroid hormones are known to stimulate maturation and brain development. Aquaporin 4 (AQP4) is a key factor mediating the cell swelling and edema that occurs during ischemic stroke, and plays a potential role in the migration and proliferation of GBM tumor cells. In this study, as a possible therapeutic target for GBM, we investigated the potential role of T3 in the expression of AQP4 during different stages of mouse brain development. Pregnant mice at gestational day 18, or young animals at postnatal days 27 and 57, received injection of T3 (1 μg/g) or NaOH (0.02 N vehicle). The brains of mice sacrificed on postnatal days 0, 30, and 60 were perfused with 4% paraformaldehyde and sections were prepared for immunohistochemistry of AQP4. AQP4 immunofluorescence was measured in the mouse brains and human GBM cell lines. We found that distribution of AQP4 was localized in astrocytes of the periventricular, subpial, and cerebral parenchyma. Newborn mice treated with T3 showed a significant decrease in AQP4 immunoreactivity followed by an increased expression at P30 and a subsequent stabilization of aquaporin levels in adulthood. All GBM cell lines examined exhibited significantly lower AQP4 expression than cultured astrocytes. T3 treatment significantly downregulated AQP4 in GBM-95 cells but did not influence the rate of GBM cell migration measured 24 h after treatment initiation. Collectively, our results showed that AQP4 expression is developmentally regulated by T3 in astrocytes of the cerebral cortex of newborn and young mice, and is discretely downregulated in GBM cells. These findings indicate that higher concentrations of T3 thyroid hormone would be more suitable for reducing AQP4 in GBM tumorigenic cells, thereby resulting in better outcomes regarding the reduction of brain tumor cell migration and proliferation.

Application of a vertical charged-particle irradiation platform in glioblastoma multiforme cancer stem cell research

Cancer stem cells (CSCs) are characterized by two critical properties similar to those of normal stem cells, namely, self-renewal and differentiation. Therefore, they play a crucial role in tumor development and tumor treatment responses. Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor in humans, with extremely poor survival rates. GBM CSCs are believed to contribute to cancer initiation, invasion, metastasis, and recurrence, and they can also lead to poor conventional radiation therapy and chemotherapy outcomes. Efficiently eliminating CSCs is thus crucial to developing GBM treatment strategies. This study aimed to demonstrate the application of a vertical charged-particle irradiation platform in CSC research. The cell irradiation results indicated that GBM CSCs were more radio-resistant and had a higher survival rate than ordinary GBM tumor cells. Expression of DNA double-strand break (DSB) repair modulation protein in GBM CSCs was also higher than in ordinary GBM tumor cells, suggesting that the radioresistance of GBM CSCs might be relative to efficient DNA DSB repair. Targeting the DNA DSB repair mechanism could thus be a potential strategy for enhancing GBM tumor control. All of the results demonstrated that the vertical charged-particle irradiation platform provides a suitable environment for CSC charged-particle irradiation research.