The development of dendritic cell vaccine-based immunotherapies for glioblastoma

A systematic review of immunotherapy in high-grade glioma: learning from the past to shape future perspectives

High-grade gliomas (HGGs) constitute the most common malignant primary brain tumor with a poor prognosis despite the standard multimodal therapy. In recent years, immunotherapy has changed the prognosis of many cancers, increasing the hope for HGG therapy. We conducted a comprehensive search on PubMed, Scopus, Embase, and Web of Science databases to include relevant studies. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Fifty-two papers were finally included (44 phase II and eight phase III clinical trials) and further divided into four different subgroups: 14 peptide vaccine trials, 15 dendritic cell vaccination (DCV) trials, six immune checkpoint inhibitor (ICI) trials, and 17 miscellaneous group trials that included both "active" and "passive" immunotherapies. In the last decade, immunotherapy created great hope to increase the survival of patients affected by HGGs; however, it has yielded mostly dismal results in the setting of phase III clinical trials. An in-depth analysis of these clinical results provides clues about common patterns that have led to failures at the clinical level and helps shape the perspective for the next generation of immunotherapies in neuro-oncology.

Efficacy of cell-based immunotherapies on patients with glioma: an umbrella review of systematic reviews and meta-analysis protocol

INTRODUCTION

Glial brain tumours are highly mortal and are noted as major neurosurgical challenges due to frequent recurrence or progression. Despite standard-of-care treatment for gliomas, the prognosis of patients with higher-grade glial tumours is still poor, and hence empowering antitumour immunity against glioma is a potential future oncological prospect. This review is designed to improve our understanding of the efficacy of cell-based immunotherapies for glioma.

METHODS AND ANALYSIS

This systematic review will be performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of main electronic databases: PubMed/MEDLINE, Scopus, ISI Web of Science EMBASE and ProQuest will be done on original articles, followed by a manual review of review articles. Only records in English and only clinical trials will be encountered for full-text review. All the appropriate studies that encountered the inclusion criteria will be screened, selected and then will undergo data extraction step by two independent authors. For meta-analyses, data heterogeneity for each parameter will be first evaluated by Cochran's Q and I2 statistics. In case of possible heterogeneity, a random-effects meta-analysis will be performed and for homogenous data, fixed-effects models will be selected for reporting the results of the proportional meta-analysis. Bias risk will be assessed through Begg's and Egger's tests and will also be visualised by Funnel plots.

ETHICS AND DISSEMINATION

As this study will be a systematic review without human participants' involvement, no ethical registration is required and meta-analysis will be presented at a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022373297.

Therapeutic cell-based vaccines for glioblastoma multiforme

Glioblastoma multiforme (GBM), a highly aggressive tumor, poses significant challenges in achieving successful treatment outcomes. Conventional therapeutic modalities including surgery, radiation, and chemotherapy have demonstrated limited efficacy, primarily attributed to the complexities associated with drug delivery to the tumor site and tumor heterogeneity. To address this critical need for innovative therapies, the potential of cancer vaccines utilizing tumor cells and dendritic cells has been explored for GBM treatment. This article provides a comprehensive review of therapeutic vaccinations employing cell-based vaccine strategies for the management of GBM. A meticulous evaluation of 45 clinical trials involving more than 1500 participants revealed that cell-based vaccinations have exhibited favorable safety profiles with minimal toxicity. Moreover, these vaccines have demonstrated modest improvements in overall survival and progression-free survival among patients. However, certain limitations still persist. Notably, there is a need for advancements in the development of potent antigens to evoke immune responses, as well as the optimization of dosage regimens. Consequently, while cell-based vaccinations show promise as a potential therapeutic approach for GBM, further research is imperative to overcome the current limitations. The ultimate objective is to surmount these obstacles and establish cell-based vaccinations as a standard therapeutic modality for GBM.

Advancements in dendritic cell vaccination: enhancing efficacy and optimizing combinatorial strategies for the treatment of glioblastoma

Glioblastomas (GBM) are highly invasive, malignant primary brain tumors. The overall prognosis is poor, and management of GBMs remains a formidable challenge, necessitating novel therapeutic strategies such as dendritic cell vaccinations (DCVs). While many early clinical trials demonstrate an induction of an antitumoral immune response, outcomes are mixed and dependent on numerous factors that vary between trials. Optimization of DCVs is essential; the selection of GBM-specific antigens and the utilization of 18F-fludeoxyglucose Positron Emission Tomography (FDG-PET) may add significant value and ultimately improve outcomes for patients undergoing treatment for glioblastoma. This review provides an overview of the mechanism of DCV, assesses previous clinical trials, and discusses future strategies for the integration of DCV into glioblastoma treatment protocols. To conclude, the review discusses challenges associated with the use of DCVs and highlights the potential of integrating DCV with standard therapies.

The Current Status, Challenges, and Future Potential of Therapeutic Vaccination in Glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor and confers a dismal prognosis. With only two FDA-approved therapeutics showing modest survival gains since 2005, there is a great need for the development of other disease-targeted therapies. Due, in part, to the profound immunosuppressive microenvironment seen in GBMs, there has been a broad interest in immunotherapy. In both GBMs and other cancers, therapeutic vaccines have generally yielded limited efficacy, despite their theoretical basis. However, recent results from the DCVax-L trial provide some promise for vaccine therapy in GBMs. There is also the potential that future combination therapies with vaccines and adjuvant immunomodulating agents may greatly enhance antitumor immune responses. Clinicians must remain open to novel therapeutic strategies, such as vaccinations, and carefully await the results of ongoing and future trials. In this review of GBM management, the promise and challenges of immunotherapy with a focus on therapeutic vaccinations are discussed. Additionally, adjuvant therapies, logistical considerations, and future directions are discussed.

Pharmacological inhibition of the ubiquitin-specific protease 8 effectively suppresses glioblastoma cell growth

Glioblastoma (GBM) is a malignant brain tumor. The purpose of this study is to estimate the potential effects and underlying mechanisms of a ubiquitin-specific protease 8 (USP8) small-molecule inhibitor on the phenotypic characteristics of GBM cells. The growth, migration, invasion, and stemness of GBM LN229 and T98G cells were evaluated by conducting cell proliferation, colony formation, wound healing, transwell, Ki-67 staining, spheroid formation, and ionizing radiation assays, and the results collectively showed the suppressive effects of USP8 inhibition on GBM cells. Furthermore, transcriptomic profiling of GBM cells treated with the USP8 inhibitor deubiquitinase (DUB)-IN-1 revealed significantly altered mRNA expression induced by pharmacological USP8 inhibition, from which we confirmed downregulated Aurora kinase A (AURKA) protein levels using immunoblotting assays. Our findings indicated that the proliferation, invasion, and stemness of LN229 and T98G cells were markedly suppressed by USP8 inhibition. Pharmacological USP8 suppression elicits multiple tumor-inhibitory effects, likely through dysregulating various mRNA expression events, including that of the key cell cycle regulator and oncogenic protein AURKA. Therefore, our observations corroborate the GBM-supportive roles of USP8 and suggest pharmacological USP8 inhibition is a viable therapeutic approach to target GBM. The purpose of this study was to investigate the effect and mechanism of action of the USP8 inhibitor DUB-IN-1 on GBM.

p53 inhibits the Urea cycle and represses polyamine biosynthesis in glioma cell lines

Glioma is the most common malignant tumor of the central nervous system. The urea cycle (UC) is an essential pathway to convert excess nitrogen and ammonia into the less toxic urea in humans. However, less is known about the functional significance of the urea cycle in glioma. p53 functions as a tumor suppressor and modulates several cellular functions and disease processes. In the present study, we aimed to explore whether p53 influences glioma progression by regulating the urea cycle. Here, we demonstrated the inhibitory impact of p53 on the expression of urea cycle enzymes and urea genesis in glioma cells. The level of polyamine, a urea cycle metabolite, was also regulated by p53 in glioma cells. Carbamoyl phosphate synthetase-1 (CPS1) is the first key enzyme involved in the urea cycle. Functionally, we demonstrated that CPS1 knockdown suppressed glioma cell proliferation, migration and invasion. Mechanistically, we demonstrated that the expression of ornithine decarboxylase (ODC), which determines the generation of polyamine, was regulated by CPS1. In addition, the impacts of p53 knockdown on ODC expression, glioma cell growth and aggressive phenotypes were significantly reversed by CPS1 inhibition. In conclusion, these results demonstrated that p53 inhibits polyamine metabolism by suppressing the urea cycle, which inhibits glioma progression.

Immunotherapy associated central nervous system complications in primary brain tumors

Advances clarifying the genetics and function of the immune system within the central nervous system (CNS) and brain tumor microenvironment have led to increasing momentum and number of clinical trials using immunotherapy for primary brain tumors. While neurological complications of immunotherapy in extra-cranial malignancies is well described, the CNS toxicities of immunotherapy in patients with primary brain tumors with their own unique physiology and challenges are burgeoning. This review highlights the emerging and unique CNS complications associated with immunotherapy including checkpoint inhibitors, oncolytic viruses, adoptive cell transfer/chimeric antigen receptor (CAR) T cell and vaccines for primary brain tumors, as well as reviews modalities that have been currently employed or are undergoing investigation for treatment of such toxicities.

Dendritic Cell-Based Vaccines Against Cancer: Challenges, Advances and Future Opportunities

As the most potent professional antigen presenting cells, dendritic cells (DCs) have the ability to activate both naive CD4 and CD8 T cells. Recognized for their exceptional ability to cross-present exogenous antigens to prime naive antigen-specific CD8 T cells, DCs play a critical role in generating CD8 T cell immunity, as well as mediating CD8 T cell tolerance to tumor antigens. Despite the ability to potentiate host CD8 T cell-mediated anti-tumor immunity, current DC-based cancer vaccines have not yet achieved the promised success clinically with the exception of FDA-approved Provenge. Interestingly, recent studies have shown that type 1 conventional DCs (cDC1s) play a critical role in cross-priming tumor-specific CD8 T cells and determining the anti-tumor efficacy of cancer immunotherapies including immune checkpoint blockade (ICB). Together with promising clinical results in neoantigen-based cancer vaccines, there is a great need for DC-based vaccines to be further developed and refined either as monotherapies or in combination with other immunotherapies. In this review, we will present a brief review of DC development and function, discuss recent progress, and provide a perspective on future directions to realize the promising potential of DC-based cancer vaccines.

Cell‑based immunotherapy of glioblastoma multiforme (Review)

Glioblastoma multiforme (GBM) is the most aggressive and lethal primary glial brain tumor. It has an unfavorable prognosis and relatively ineffective treatment protocols, with the median survival of patients being ~15 months. Tumor resistance to treatment is associated with its cancer stem cells (CSCs). At present, there is no medication or technologies that have the ability to completely eradicate CSCs, and immunotherapy (IT) is only able to prolong the patient's life. The present review aimed to investigate systemic solutions for issues associated with immunosuppression, such as ineffective IT and the creation of optimal conditions for CSCs to fulfill their lethal potential. The present review also investigated the main methods involved in local immunosuppression treatment, and highlighted the associated disadvantages. In addition, novel treatment options and targets for the elimination and regulation of CSCs with adaptive and active IT are discussed. Antagonists of TGF-β inhibitors, immune checkpoints and other targeted medication are also summarized. The role of normal hematopoietic stem cells (HSCs) in the mechanisms underlying systemic immune suppression development in cases of GBM is analyzed, and the potential reprogramming of HSCs during their interaction with cancer cells is discussed. Moreover, the present review emphasizes the importance of the aforementioned interactions in the development of immune tolerance and the inactivation of the immune system in neoplastic processes. The possibility of solving the problem of systemic immunosuppression during transplantation of donor HSCs is discussed.

USP5 Sustains the Proliferation of Glioblastoma Through Stabilization of CyclinD1

Glioblastoma multiforme (GBM) is one of the most malignant primary tumors in humans. Despite standard therapeutic strategy with tumor resection combined with radiochemotherapy, the prognosis remains disappointed. Recently, deubiquitinating enzymes (DUBs) has been reported as potential cancer therapy targets due to their multifunctions involved in the regulation of tumorigenesis, cell cycle, apoptosis, and autophagy. In this study, we found that knockdown of ubiquitin specific protease (USP5), a family member of DUB, could significantly suppress GBM cell line U251 and DBTRG-05MG proliferation and colony formation by inducing cell cycle G1/S arrest, which was correlated with downregulation of CyclinD1 protein level. CyclinD1 had been reported to play a critical role in the tumorigenesis and development of GBM via regulating cell cycle transition. Overexpression of USP5 could significantly extend the half-life of CyclinD1, while knockdown of USP5 decreased the protein level of CyclinD1, which could be restored by proteasome inhibitor MG-132. Indeed, USP5 was found to directly interact with CyclinD1, and decrease its K48-linked polyubiquitination level. Furthermore, knockdown of USP5 in U251 cells remarkably inhibited tumor growth in vivo. Taken together, these findings demonstrate that USP5 plays a critical role in tumorigenesis and progression of GBM by stabilizing CyclinD1 protein. Targeting USP5 could be a potential therapeutic strategy for GBM.

DC-Derived Exosomes for Cancer Immunotherapy

As the initiators of adaptive immune responses, DCs play a central role in regulating the balance between CD8 T cell immunity versus tolerance to tumor antigens. Exploiting their function to potentiate host anti-tumor immunity, DC-based vaccines have been one of most promising and widely used cancer immunotherapies. However, DC-based cancer vaccines have not achieved the promised success in clinical trials, with one of the major obstacles being tumor-mediated immunosuppression. A recent discovery on the critical role of type 1 conventional DCs (cDC1s) play in cross-priming tumor-specific CD8 T cells and determining the anti-tumor efficacy of cancer immunotherapies, however, has highlighted the need to further develop and refine DC-based vaccines either as monotherapies or in combination with other therapies. DC-derived exosomes (DCexos) have been heralded as a promising alternative to DC-based vaccines, as DCexos are more resistance to tumor-mediated suppression and DCexo vaccines have exhibited better anti-tumor efficacy in pre-clinical animal models. However, DCexo vaccines have only achieved limited clinical efficacy and failed to induce tumor-specific T cell responses in clinical trials. The lack of clinical efficacy might be partly due to the fact that all current clinical trials used peptide-loaded DCexos from monocyte-derived DCs. In this review, we will focus on the perspective of expanding current DCexo research to move DCexo cancer vaccines forward clinically to realize their potential in cancer immunotherapy.

Making a Cold Tumor Hot: The Role of Vaccines in the Treatment of Glioblastoma

The use of immunotherapies for the treatment of brain tumors is a topic that has garnered considerable excitement in recent years. Discoveries such as the presence of a glymphatic system and immune surveillance in the central nervous system (CNS) have shattered the theory of immune privilege and opened up the possibility of treating CNS malignancies with immunotherapies. However, despite many immunotherapy clinical trials aimed at treating glioblastoma (GBM), very few have demonstrated a significant survival benefit. Several factors for this have been identified, one of which is that GBMs are immunologically "cold," implying that the cancer does not induce a strong T cell response. It is postulated that this is why clinical trials using an immune checkpoint inhibitor alone have not demonstrated efficacy. While it is well established that anti-cancer T cell responses can be facilitated by the presentation of tumor-specific antigens to the immune system, treatment-related death of GBM cells and subsequent release of molecules have not been shown to be sufficient to evoke an anti-tumor immune response effective enough to have a significant impact. To overcome this limitation, vaccines can be used to introduce exogenous antigens at higher concentrations to the immune system to induce strong tumor antigen-specific T cell responses. In this review, we will describe vaccination strategies that are under investigation to treat GBM; categorizing them based on their target antigens, form of antigens, vehicles used, and pairing with specific adjuvants. We will review the concept of vaccine therapy in combination with immune checkpoint inhibitors, as it is hypothesized that this approach may be more effective in overcoming the immunosuppressive milieu of GBM. Clinical trial design and the need for incorporating robust immune monitoring into future studies will also be discussed here. We believe that the integration of evolving technologies of vaccine development, delivery, and immune monitoring will further enhance the role of these therapies and will likely remain an important area of investigation for future treatment strategies for GBM patients.

DC-Based Vaccines for Cancer Immunotherapy

As the sentinels of the immune system, dendritic cells (DCs) play a critical role in initiating and regulating antigen-specific immune responses. Cross-priming, a process that DCs activate CD8 T cells by cross-presenting exogenous antigens onto their MHCI (Major Histocompatibility Complex class I), plays a critical role in mediating CD8 T cell immunity as well as tolerance. Current DC vaccines have remained largely unsuccessful despite their ability to potentiate both effector and memory CD8 T cell responses. There are two major hurdles for the success of DC-based vaccines: tumor-mediated immunosuppression and the functional limitation of the commonly used monocyte-derived dendritic cells (MoDCs). Due to their resistance to tumor-mediated suppression as inert vesicles, DC-derived exosomes (DCexos) have garnered much interest as cell-free therapeutic agents. However, current DCexo clinical trials have shown limited clinical benefits and failed to generate antigen-specific T cell responses. Another exciting development is the use of naturally circulating DCs instead of in vitro cultured DCs, as clinical trials with both human blood cDC2s (type 2 conventional DCs) and plasmacytoid DCs (pDCs) have shown promising results. pDC vaccines were particularly encouraging, especially in light of promising data from a recent clinical trial using a human pDC cell line, despite pDCs being considered tolerogenic and playing a suppressive role in tumors. However, how pDCs generate anti-tumor CD8 T cell immunity remains poorly understood, thus hindering their clinical advance. Using a pDC-targeted vaccine model, we have recently reported that while pDC-targeted vaccines led to strong cross-priming and durable CD8 T cell immunity, cross-presenting pDCs required cDCs to achieve cross-priming in vivo by transferring antigens to cDCs. Antigen transfer from pDCs to bystander cDCs was mediated by pDC-derived exosomes (pDCexos), which similarly required cDCs for cross-priming of antigen-specific CD8 T cells. pDCexos thus represent a new addition in our arsenal of DC-based cancer vaccines that would potentially combine the advantage of pDCs and DCexos.

SMAGP knockdown inhibits the malignant phenotypes of glioblastoma cells by inactivating the PI3K/Akt pathway

Small trans-membrane and glycosylated protein (SMAGP), a novel small trans-membrane glycoprotein, is reported to be upregulated in multiple cancers and involved in tumor development. However, little is known about its role in the development of glioblastoma (GBM). GEPIA database was used to analyze SMAGP expression and evaluate the prognostic value of SMAGP in GBM. GO and KEGG pathway enrichment analyses were used to predict the biological functions and pathways of SMAGP and 948 SMAGP-correlated genes using DAVID database. Cell viability, colony formation ability, apoptosis, and invasion were evaluated by MTT, colony formation assay, flow cytometry analysis, and Transwell invasion assay, respectively. Western blot was applied to detect the expression of SMAGP, matrix metalloproteinase (MMP)-2, and MMP-9 and analyze the changes of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling. Results showed that SMAGP was upregulated and correlated with poor prognosis in GBM. Functional annotation analysis revealed that SMAGP and 948 SMAGP-correlated genes were primarily associated with cell adhesion and PI3K/Akt pathway. SMAGP interference inhibited cell viability and colony formation ability and promoted apoptosis in GBM cells. Moreover, SMAGP interference inhibited GBM cell invasion and suppressed MMP-2 and MMP-9 expression. Additionally, SMAGP silencing inhibited the PI3K/Akt pathway in GBM cells. Overexpression of Akt abolished the effects of SMAGP knockdown on the malignant phenotypes of GBM cells. In conclusion, SMAGP silencing inhibited the malignant phenotypes of GBM cells by inactivating the PI3K/Akt pathway.

Preventing Lethal Prostate Cancer with Diet, Supplements, and Rx: Heart Healthy Continues to Be Prostate Healthy and "First Do No Harm" Part III

PURPOSE OF REVIEW

To discuss the overall and latest observations of the effect of diet, lifestyle, supplements, preventive vaccinations, and some prescription heart healthy medications for prostate cancer prevention within a 3-part series of publications.

RECENT FINDINGS

The concept of maximizing heart health to prevent aggressive prostate cancer continues to be solidified with additional prospective observational and randomized controlled trial data. Heart healthy is prostate healthy, but heart unhealthy is prostate unhealthy. The primary goal for medical providers of reducing all-cause and cardiovascular disease (CVD) morbidity and mortality correlates with maximizing prostate cancer prevention. The obesity epidemic in children and adults along with research from multiple, diverse disciplines has only strengthened the nexus between heart and prostate health. Greater dietary adherence toward a variety of healthy foods is associated with a graded reduction in the probability of CVD and aggressive cancer. Preventing prostate cancer via dietary supplements should encourage a "first do no harm" or less-is-more approach until future evidence can reverse the concerning trend that more supplementation has resulted in either no impact or an increased risk of prostate cancer. Supplements to reduce side effects of some cancer treatments appear to have more encouraging data. A discussion of quality control (QC) before utilizing any pill also requires attention. Medications or interventions that potentially improve heart health including statins, aspirin, and metformin (S.A.M.), specific beta-blocker medications, and even preventive vaccines are in general generic, low cost, "natural," and should continue to garner research interest. A watershed moment in medical education has arrived where the past perception of a diverse number of trees seemingly separated by vast distances, in reality, now appears to exist within the same forest.

LncRNA SAMMSON Knockdown Inhibits the Malignancy of Glioblastoma Cells by Inactivation of the PI3K/Akt Pathway

Dysregulated lncRNAs are proposed to be tightly associated with the progression of various tumors including glioblastoma (GBM). LncRNA Survival Associated Mitochondrial Melanoma-Specific Oncogenic Non-Coding RNA (SAMMSON) has been reported to be an oncogenic lncRNA in several tumors. Nevertheless, the specific role and molecular mechanism of SAMMSON in GBM progression remain unknown. Expression of SAMMSON in GBM tissues and cells was detected by qRT-PCR. CCK-8 and LDH release assays were applied to evaluate cellular viability. Invasion effect was assessed by Transwell invasion assay and western blot analysis of E-cadherin and N-cadherin expression. Apoptosis was detected using flow cytometry analysis and caspase-3 activity assay. The protein levels of phosphatidylinositol-3-kinase (PI3K), phosphorylated (p)-PI3K, protein kinase B (Akt) and p-Akt were estimated by western blot. We found that SAMMSON was highly expressed in GBM tissues and cells. SAMMSON knockdown suppressed cell viability and increased LDH release in GBM cells. Moreover, SAMMSON silencing impeded the invasive ability of GBM cells by regulating epithelial-to-mesenchymal transition (EMT). Furthermore, SAMMSON downregulation increased the apoptotic rate and caspase-3 activity in GBM cells. Additionally, it was demonstrated that the PI3K/Akt pathway was inhibited following SAMMSON silencing in GBM cells. Rescue assays revealed that activation of the PI3K/Akt pathway by 740Y-P abolished SAMMSON knockdown-induced viability reduction, invasion suppression and apoptosis in GBM cells. Taken together, lncRNA SAMMSON knockdown inhibited the malignancy of GBM cells by inactivation of the PI3K/Akt pathway.

Perspective on potential impact of HIV central nervous system latency on eradication

: Given the challenges of life-long adherence to suppressive HIV antiretroviral therapy (ART) and possibilities of comorbidities, such as HIV association neurocognitive disorder, HIV remission and eradication are desirable goals for people living with HIV. In some individuals, there is evidence that HIV persists and replicates in the CNS, impacting the success of HIV remission interventions. This article addresses the role of HIV CNS latency on HIV eradication, examines the effects of early ART, latency-modifying agents, antibody-based and T-cell enhancing therapies on the CNS as well as ART interruption in remission studies. We propose the integration of CNS monitoring into such studies in order to clarify the short-term and long-term neurological safety of experimental agents and treatment interruption, and to better characterize their effects on HIV CNS persistence.

The evolving role of antiangiogenic therapies in glioblastoma multiforme: current clinical significance and future potential

Introduction: Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, but its prognosis remains poor despite significant advances in our understanding of its molecular biology and investigation of numerous treatment modalities. Despite conventional treatment consisting of surgical resection, radiotherapy, and temozolomide marginally prolonging survival, most GBM patients die within 2 years of initial diagnosis. Bevacizumab (Bev) is the best-studied antiangiogenic agent for GBM and currently the only FDA-approved second-line treatment. Areas covered: Areas covered in this review include the molecular pathways of angiogenesis in glioblastoma, specifically the overexpression of vascular endothelial growth factor (VEGF) and robust formation of tumor neovasculature. In addition, this review covers pharmacological targeting of this process as a longstanding attractive clinical strategy, specifically by Bev. Expert opinion: This review attempts to discuss the history of early studies of antiangiogenic treatment for GBM that eventually failed in subsequent studies and the evolving modern role of Bev in the course of treatment for a variety of indications, including symptom control, reduced glucocorticoid use, and improved quality of life.

Expansion of effector and memory T cells is associated with increased survival in recurrent glioblastomas treated with dendritic cell immunotherapy

Background

The efficacy of dendritic cell (DC) immunotherapy as a single therapeutic modality for the treatment of glioblastoma (GBM) patients remains limited. In this study, we evaluated in patients with GBM recurrence the immune-mediated effects of DC loaded with autologous tumor lysate combined with temozolomide (TMZ) or tetanus toxoid (TT).

Methods

In the phase I-II clinical study DENDR2, 12 patients were treated with 5 DC vaccinations combined with dose-dense TMZ. Subsequently, in eight patients, here defined as Variant (V)-DENDR2, the vaccine site was preconditioned with TT 24 hours before DC vaccination and TMZ was avoided. As a survival endpoint for these studies, we considered overall survival 9 months (OS9) after second surgery. Patients were analyzed for the generation of effector, memory, and T helper immune response.

Results

Four of 12 DENDR2 patients reached OS9, but all failed to show an immunological response. Five of eight V-DENDR2 patients (62%) reached OS9, and one patient is still alive (OS >30 months). A robust CD8⁺ T-cell activation and memory T-cell formation were observed in V-DENDR2 OS>9. Only in these patients, the vaccine-specific CD4⁺ T-cell activation (CD38⁺/HLA-DR⁺) was paralleled by an increase in TT-induced CD4⁺/CD38^low/CD127^high memory T cells. Only V-DENDR2 patients showed the formation of a nodule at the DC injection site infiltrated by CCL3-expressing CD4⁺ T cells.

Conclusions

TT preconditioning of the vaccine site and lack of TMZ could contribute to the efficacy of DC immunotherapy by inducing an effector response, memory, and helper T-cell generation.

Blockade of STAT3 Signaling Contributes to Anticancer Effect of 5-Acetyloxy-6,7,8,4'-Tetra-Methoxyflavone, a Tangeretin Derivative, on Human Glioblastoma Multiforme Cells

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with poor prognosis, largely due to resistance to current radiotherapy and Temozolomide chemotherapy. The constitutive activation of Signal Transducer and Activator of Transcription 3 (STAT3) is evidenced as a pivotal driver of GBM pathogenesis and therapy resistance, and hence, is a promising GBM drug target. 5-acetyloxy-6,7,8,4'-tetramethoxyflavone (5-AcTMF) is an acetylated derivative of Tangeretin which is known to exert anticancer effects on breast, colon, lung, and multiple myeloma; however, its effect on GBM remains elusive. Herein, we reported that 5-AcTMF suppressed the viability and clonogenicity along with inducing apoptosis in multiple human GBM cell lines. Mechanistic analyses further revealed that 5-AcTMF lowered the levels of Tyrosine 705-phosphorylated STAT3 (p-STAT3), a canonical marker of STAT3 activation, but also dampened p-STAT3 upregulation elicited by Interleukin-6. Notably, ectopic expression of dominant-active STAT3 impeded 5-AcTMF-induced suppression of viability and clonogenicity plus apoptosis induction in GBM cells, confirming the prerequisite of STAT3 blockage for the inhibitory action of 5-AcTMF on GBM cell survival and growth. Additionally, 5-AcTMF impaired the activation of STAT3 upstream kinase JAK2 but also downregulated antiapoptotic BCL-2 and BCL-xL in a STAT3-dependent manner. Moreover, the overexpression of either BCL-2 or BCL-xL abrogated 5-AcTMF-mediated viability reduction and apoptosis induction in GBM cells. Collectively, we, for the first time, revealed the anticancer effect of 5-AcTMF on GBM cells, which was executed via thwarting the JAK2-STAT3-BCL-2/BCL-xL signaling axis. Our findings further implicate the therapeutic potential of 5-AcTMF for GBM treatment.

IRGM promotes glioma M2 macrophage polarization through p62/TRAF6/NF-κB pathway mediated IL-8 production

Alternatively activated (M2) macrophage promotes glioma progression and immune escape as the most immunocyte in glioma microenvironment. Finding out the key protein regulating M2 macrophage polarization is necessary for improving treatment. Whether immunity related GTPase M (IRGM) is involved in glioma development and M2 macrophage polarization is unknown. IRGM and M2 macrophage marker CD206 expression were examined using immunohistochemistry among 35 glioma and 11 non-cancerous brain specimens. We found IRGM scores were positively correlated with CD206 scores in glioma specimens and monocyte proportion in blood samples. A172 glioma cells transfected with either IRGM knock-down lentivirus (Lenti-IRGM) or control lentivirus (Lenti-HK) were subcutaneously injected into nude mice. In vivo, xenografted glioma size of the Lenti-IRGM group was smaller and had weaker fluorescence signal than Lenti-HK control group. Immunofluorescence results showed that there was obviously decreased IRGM, CD206, and IL-8 expression in the mice glioma of Lenti-IRGM group than Lenti-HK control group. In vitro, flow cytometry results showed that M2 polarization from THP-1 cocultured with Lenti-IRGM glioma cells decreased in contrast to that with Lenti-HK glioma cells; there were less interleukin-8 (IL-8) and macrophage inflammation protein 3-α (MIP-3α), but more interleukin-6 (IL-6) in the supernatant of Lenti-IRGM glioma cells than matched control. Western blot and immunofluorescence displayed that IRGM strongly promoted sequestosome-1 (p62/SQSTM1), necrosis factor receptor-activating factor 6 (TRAF6) expression and NF-κB transportation to the nucleus. Realtime PCR results demonstrated IRGM also promoted NF-κB downstream cytokines IL-8 and MIP-3α mRNA expression. These data suggested that IRGM could promote glioma development and M2 macrophage polarization by regulating p62/TRAF6/NF-κB pathway-mediated IL-8 production.

Modulation of Biological Activities in Glioblastoma Mediated by Curcumin

Curcumin is an alkaloid with various pharmacologic properties; numerous investigations have suggested that in the Central Nervous System, Curcumin has anti-inflammatory, antimicrobial, antioxidant, and antitumor effects. Gliomas are the most common primary intracranial tumors in adults. The prognosis of glioblastoma is still dismal. In this review, we profile that Curcumin could suppress cell proliferation and induce apoptosis of cancer cells and genomic modulation. In particular, Curcumin could exert its therapeutic effect via modulating miRNA, affecting a variety of miRNAs involved in the response to cancer therapy. The combination of Curcumin with chemotherapeutic drugs or radiotherapy could prime the sensitivity of cancer cells to chemotherapy or radiotherapy. We also discuss the use of exosomes as Curcumin delivery vehicles. In this context, exosomes containing Curcumin may change the behavior of recipient cells by targeting a sequence of cellular and molecular pathways. Hence, the application of exosomes containing Curcumin may prove to be an emerging area of research in cancer therapy.

Ubiquitin-specific protease 4 promotes glioblastoma multiforme via activating ERK pathway

Background

Glioblastoma multiforme (GBM) is one of the most common brain tumors in adults. Current treatments cannot increase survival to a large extent, as the glioblastoma development mechanisms remain unknown. It has been well documented that ubiquitination contributes to tumor initiation and/or progression in many kinds of cancer. Ubiquitin-specific protease 4 (USP4), a member of deubiquitinating enzymes (DUBs) family, can remove ubiquitin residues and play a role in cancer development.

Methods

In the current study, lentiviruses were used to manipulate the expression of USP4. Real-time PCR and Western blot were used to measure the expression level of USP4. Then, CCK-8 and annexin-V staining were used to detect cell proliferation and cell apoptosis, respectively.

Results

First, we found that USP4 was highly upregulated in GBM tissues in comparison with that in normal tissues and high level of USP4 correlated with poor prognosis. Moreover, knockdown of USP4 could significantly inhibit cell proliferation and increase cell apoptosis in U87 and T98G cells. Cells with stable USP4 reduction exhibited slower tumor growth rate and smaller tumor size than the control group cells in a xenograft mouse model. Inhibition of USP4 downregulated the expression of PCNA, Bcl-2 and p-ERK1/2, but upregulated the expression of Bax both in vitro and in vivo. Inversely, USP4 overexpression could attenuate the effects contributed by ERK inhibitor. TGF-βR inhibition reduced level of TGF-βR1, p-smad2 and p-ERK1/2 which can partially be rescued by USP4 overexpression.

Conclusion

USP4, as a potential novel oncogene, promotes GBM by activation of ERK pathway through regulating TGF-β.

Novel Immunotherapeutics for Treatment of Glioblastoma: The Last Decade of Research

Despite surgical resection and adjuvant chemoradiation, survival for glioblastoma remains poor. Because of the dismal prognosis, attention has shifted to alternative adjuvant treatment modalities. Although traditionally limited to systemic malignancies (melanoma, lung and colon cancer), the field of immunotherapy has recently identified glioblastoma as a potential target for new treatments. Anti-tumor vaccines (dendritic cell/heat shock), checkpoint inhibitors, chimeric T-cell receptors, and virotherapy all have been preliminarily trialed in glioblastoma patients with reasonable success and safety. Although there are certainly limitations due to autoimmune reactions and immune escape, immunotherapeutics hold much promise in the future treatment paradigms for malignant glioma.

Immunotherapies for malignant glioma

Glioblastoma multiforme (GBM) is a highly malignant primary brain cancer with a dreadful overall survival and for which treatment options are limited. Recent breakthroughs in novel immune-related treatment strategies for cancer have spurred interests in usurping the power of the patient's immune system to recognize and eliminate GBM. Here, we discuss the unique properties of GBM's tumor microenvironment, the effects of GBM standard on care therapy on tumor-associated immune cells, and review several approaches aimed at therapeutically targeting the immune system for GBM treatment. We believe that a comprehensive understanding of the intricate micro-environmental landscape of GBM will abound into the development of novel immunotherapy strategies for GBM patients.

Novel Immunotherapeutics for the Treatment of Glioblastoma: The Last Decade of Research

Despite surgical resection and adjuvant chemoradiation, survival for glioblastoma remains poor. Because of the dismal prognosis, attention has shifted to alternative adjuvant treatment modalities. Although traditionally limited to systemic malignancies (melanoma, lung and colon cancer), the field of immunotherapy has recently identified glioblastoma as a potential target for new treatments. Anti-tumor vaccines (dendritic cell/heat shock), checkpoint inhibitors, chimeric T-cell receptors, and virotherapy all have been preliminarily trialed in glioblastoma patients with reasonable success and safety. Although there are limitations due to autoimmune reactions and immune escape, immunotherapeutics hold much promise in the future treatment paradigms for malignant glioma.

Immune Checkpoint Blockade Biology in Mouse Models of Glioblastoma

Glioblastoma Multiforme (GBM) is a highly malignant primary brain cancer that is associated with abysmal prognosis. The median survival of GBM patients is ∼15 months and there have not been any significant advance in therapies in over a decade, leaving treatment options limited. There is clearly an unmet need for GBM treatment. Immunotherapies are treatments based on usurping the power of the host's immune system to recognize and eliminate cancer cells. They have recently proven to be a successful strategy for combating a variety of cancers. Of the various types of immunotherapies, checkpoint blockade approaches have thus far produced significant clinical responses in several cancers including melanoma, non small-cell lung cancer, renal cancer, and prostate cancer. This review focuses on the biological rationale for using checkpoint blockade immunotherapeutic approaches in primary brain cancer and an up-to-date summary of current and ongoing checkpoint inhibitors-based clinical trials for malignant glioma. In addition, we expand on new concepts for further improving checkpoint blockade treatments, with a particular focus on the advantages of using genetically engineered mouse models for studies of immunotherapies in GBM. J. Cell. Biochem. 118: 2516-2527, 2017. © 2017 Wiley Periodicals, Inc.