Single vs. combination immunotherapeutic strategies for glioma

Glioma and Peptidergic Systems: Oncogenic and Anticancer Peptides

Glioma cells overexpress different peptide receptors that are useful for research, diagnosis, management, and treatment of the disease. Oncogenic peptides favor the proliferation, migration, and invasion of glioma cells, as well as angiogenesis, whereas anticancer peptides exert antiproliferative, antimigration, and anti-angiogenic effects against gliomas. Other peptides exert a dual effect on gliomas, that is, both proliferative and antiproliferative actions. Peptidergic systems are therapeutic targets, as peptide receptor antagonists/peptides or peptide receptor agonists can be administered to treat gliomas. Other anticancer strategies exerting beneficial effects against gliomas are discussed herein, and future research lines to be developed for gliomas are also suggested. Despite the large amount of data supporting the involvement of peptides in glioma progression, no anticancer drugs targeting peptidergic systems are currently available in clinical practice to treat gliomas.

An Update on the Clinical Status, Challenges, and Future Directions of Oncolytic Virotherapy for Malignant Gliomas

OPINION STATEMENT

Malignant gliomas are common central nervous system tumors that pose a significant clinical challenge due to the lack of effective treatments. Glioblastoma (GBM), a grade 4 malignant glioma, is the most prevalent primary malignant brain tumor and is associated with poor prognosis. Current clinical trials are exploring various strategies to combat GBM, with oncolytic viruses (OVs) appearing particularly promising. In addition to ongoing and recently completed clinical trials, one OV (Teserpaturev, Delytact®) received provisional approval for GBM treatment in Japan. OVs are designed to selectively target and eliminate cancer cells while promoting changes in the tumor microenvironment that can trigger and support long-lasting anti-tumor immunity. OVs offer the potential to remodel the tumor microenvironment and reverse systemic immune exhaustion. Additionally, an increasing number of OVs are armed with immunomodulatory payloads or combined with immunotherapy approaches in an effort to promote anti-tumor responses in a tumor-targeted manner. Recently completed oncolytic virotherapy trials can guide the way for future treatment individualization through patient preselection, enhancing the likelihood of achieving the highest possible clinical success. These trials also offer valuable insight into the numerous challenges inherent in malignant glioma treatment, some of which OVs can help overcome.

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.

Tumor Microenvironment and Glioblastoma Cell Interplay as Promoters of Therapeutic Resistance

The invasive nature of glioblastoma is problematic in a radical surgery approach and can be responsible for tumor recurrence. In order to create new therapeutic strategies, it is imperative to have a better understanding of the mechanisms behind tumor growth and invasion. The continuous cross-talk between glioma stem cells (GSCs) and the tumor microenvironment (TME) contributes to disease progression, which renders research in this field difficult and challenging. The main aim of the review was to assess the different possible mechanisms that could explain resistance to treatment promoted by TME and GSCs in glioblastoma, including the role of M2 macrophages, micro RNAs (miRNAs), and long non-coding RNAs (lncRNAs) from exosomes from the TME. A systematic review of the literature on the role of the TME in developing and promoting radioresistance and chemoresistance of GBM was performed according to PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) guidelines. A dedicated literature review search was also performed on the immunotherapeutic agents against the immune TME. We identified 367 papers using the reported keywords. The final qualitative analysis was conducted on 25 studies. A growing amount of evidence in the current literature supports the role of M2 macrophages and non-coding RNAs in promoting the mechanisms of chemo and radioresistance. A better insight into how GBM cells interact with TME is an essential step towards comprehending the mechanisms that give rise to resistance to standard treatment, which can help to pave the way for the development of novel therapeutic strategies for GBM patients.

The evolving role of checkpoint inhibitors in the treatment of urothelial carcinoma

The most prevalent pathological subtype of bladder and upper urinary tract malignancy is urothelial carcinoma (UC). Traditional therapies mainly include surgical resection, chemotherapy and radiotherapy. Checkpoint inhibitors, which are monoclonal antibodies developed to specifically target immune checkpoint molecules, have recently emerged as potential treatment options for UC patients, especially those targeting the programmed cell death protein 1 (PD-1) and its ligand (PD-L1). However, anti-PD-1/PD-L1 therapy does not work for a considerable number of UC patients. Current antitumour immunotherapy research hotspots include seeking biomarkers that might predict therapeutic effects and exploring novel immune checkpoint molecules crucial for the antitumour immune response. Hence, we will recapitulate the latest preclinical and clinical trials of 5 PD-1/PD-L1 inhibitors, 1 cytotoxic T-lymphocyte-associated protein 4 inhibitor and combination therapies for UC treatment, including combined immunotherapy and immunotherapy with chemotherapy or radiotherapy. We will also summarize other potential immune checkpoint molecules found in ongoing UC studies. Moreover, we will highlight the role of biomarkers linked with the oncological efficacy of anti-PD-1/PD-L1 immunotherapy and address the mechanisms of immunotherapy drug resistance in UC, with the hope of providing more systematic guidance for its application and development.

Dendritic cell vaccines improve the glioma microenvironment: Influence, challenges, and future directions

INTRODUCTION

Gliomas, especially the glioblastomas, are one of the most aggressive intracranial tumors with poor prognosis. This might be explained by the heterogeneity of tumor cells and the inhibitory immunological microenvironment. Dendritic cells (DCs), as the most potent in vivo functional antigen-presenting cells, link innate immunity with adaptive immunity. However, their function is suppressed in gliomas. Therefore, overcoming the dysfunction of DCs in the TME might be critical to treat gliomas.

METHOD

In this paper we proposed the specificity of the glioma microenvironment, analyzed the pathways leading to the dysfunction of DCs in tumor microenvironment of patients with glioma, summarized influence of DC-based immunotherapy on the tumor microenvironment and proposed new development directions and possible challenges of DC vaccines.

RESULT

DC vaccines can improve the immunosuppressive microenvironment of glioma patients. It will bring good treatment prospects to patients. We also proposed new development directions and possible challenges of DC vaccines, thus providing an integrated understanding of efficacy on DC vaccines for glioma treatment.

Tubeimoside-I sensitizes temozolomide-resistant glioblastoma cells to chemotherapy by reducing MGMT expression and suppressing EGFR induced PI3K/Akt/mTOR/NF-κB-mediated signaling pathway

BACKGROUND

Glioblastoma multiforme (GBM, World Health Organization [WHO] grade IV) is one of the malignant Central Nerve System (CNS) tumors with high incidence rate and poor prognosis. The use of alkylating agents, such as temozolomide (TMZ), has been the main method of cytotoxic therapy for glioma patients for decades. However, TMZ resistance may be one of the major reasons for treatment failure, so far. In searching for effective agents to reverse TMZ resistance, we found that Tubeimoside-I (TBMS1), a saponin from traditional Chinese medicine, Bolbostemma paniculatum (Maxim.) Franquet, showed activities of reversing TMZ resistance of GBM. However, the ability of TBMS1 enhancing the chemosensitivity of GBM has been rarely studied, and its underlying mechanisms remain unclear.

PURPOSE

This study purposes to reveal the synergistic effects and mechanism of TBMS1 and TMZ against TMZ-resistant GBM cells.

METHODS

CCK8 assay was used to investigate the anti-proliferative effects on grade IV glioblastoma human T98G and U118 MG cells. Cell proliferation was determined by EdU assay and clonogenic assay after TMZ plus TBMS1 treatment. Apoptosis was analyzed by flow cytometry. DNA damage and DNA Double Strand Break (DSB) were assessed by cleaved Poly (ADP-ribose) polymerase (PARP), γH2AX Foci Assay and Comet Assay, respectively. Expression of proteins associated with apoptosis and DNA repair enzymes were measured by Western blot analysis. The prognostic significance of key proteins of the epidermal growth factor receptor (EGFR) induced PI3K/Akt/mTOR/NF-κB signaling pathway was analyzed using GEPIA (http://gepia.cancer-pku.cn) and validated by Western blotting.

RESULTS

Here we demonstrated that TBMS1 sensitized TMZ-resistant T98G and U118 MG glioblastoma cells to chemotherapy and exhibited promotion of apoptosis and inhibition on cell viability, proliferation and clone formation. Coefficient of drug in interaction (CDI) values showed a notable synergistic effect between TBMS1 and TMZ. Moreover, we observed that combination of TBMS1 and TMZ induced apoptosis was accompanied by robust DSB, γH2AX Foci formation and increasing cleaved PARP, as well as the heightened ratio of Bax/Bcl-2, cleavages of caspase-3 and caspase-9. In addition, the synergistic anti-glioma effect between TBMS1 and TMZ was intimately related to the reduction of MGMT expression in TMZ-resistant GBM cells. Moreover, it was also associated with attenuated expression of EGFR, p-PI3K-p85, p-Akt (Ser473), p-mTOR (Ser2481) and p-NF-κB p65(Ser536), which implying deactivation of the EGFR induced PI3K/Akt/mTOR/NF-κB signaling pathway.

CONCLUSION

We first demonstrated that synergistic effects of TBMS1 and TMZ induced apoptosis in GBM cells through reducing MGMT expression and inhibiting the EGFR induced PI3K/Akt/mTOR/NF-κB signaling pathway. This study provides a rationale for combined application of TMZ and TBMS1 as a potential chemotherapeutic treatment for MGMT+ GBM patients.

Systematic Review on Tumor Microenvironment in Glial Neoplasm: From Understanding Pathogenesis to Future Therapeutic Perspectives

Despite the multidisciplinary management in the treatment of glioblastomas, the average survival of GBM patients is still 15 months. In recent years, molecular biomarkers have gained more and more importance both in the diagnosis and therapy of glial tumors. At the same time, it has become clear that non neoplastic cells, which constitute about 30% of glioma mass, dramatically influence tumor growth, spread, and recurrence. This is the main reason why, in recent years, scientific research has been focused on understanding the function and the composition of tumor microenvironment and its role in gliomagenesis and recurrence. The aim of this review is to summarize the most recent discovery about resident microglia, tumor-associated macrophages, lymphocytes, and the role of extracellular vesicles and their bijective interaction with glioma cells. Moreover, we reported the most recent updates about new therapeutic strategies targeting immune system receptors and soluble factors. Understanding how glioma cells interact with non-neoplastic cells in tumor microenvironment is an essential step to comprehend mechanisms at the base of disease progression and to find new therapeutic strategies for GBM patients. However, no significant results have yet been obtained in studies targeting single molecules/pathways; considering the complex microenvironment, it is likely that only by using multiple therapeutic agents acting on multiple molecular targets can significant results be achieved.

Galectins as Emerging Glyco-Checkpoints and Therapeutic Targets in Glioblastoma

Despite recent advances in diagnosis and treatment, glioblastoma (GBM) represents the most common and aggressive brain tumor in the adult population, urging identification of new rational therapeutic targets. Galectins, a family of glycan-binding proteins, are highly expressed in the tumor microenvironment (TME) and delineate prognosis and clinical outcome in patients with GBM. These endogenous lectins play key roles in different hallmarks of cancer by modulating tumor cell proliferation, oncogenic signaling, migration, vascularization and immunity. Additionally, they have emerged as mediators of resistance to different anticancer treatments, including chemotherapy, radiotherapy, immunotherapy, and antiangiogenic therapy. Particularly in GBM, galectins control tumor cell transformation and proliferation, reprogram tumor cell migration and invasion, promote vascularization, modulate cell death pathways, and shape the tumor-immune landscape by targeting myeloid, natural killer (NK), and CD8⁺ T cell compartments. Here, we discuss the role of galectins, particularly galectin-1, -3, -8, and -9, as emerging glyco-checkpoints that control different mechanisms associated with GBM progression, and discuss possible therapeutic opportunities based on inhibition of galectin-driven circuits, either alone or in combination with other treatment modalities.

Research Progress About Glioma Stem Cells in the Immune Microenvironment of Glioma

Gliomas are the most common primary tumors of the central nervous system. Due to the existence of the blood-brain barrier and its unique regional immune characteristics, the study of the immune microenvironment of gliomas is particularly important. Glioma stem cells are an important cause of initiating glioma, promoting tumor progression and leading to tumor recurrence. Immunotherapeutic strategies targeting glioma stem cells have become the focus of current research. This paper will focus on the research progress of glioma stem cells in the immune microenvironment of glioma to provide the basis for the immunotherapy of glioma.

Histone deacetylase inhibitor MPT0B291 suppresses Glioma Growth in vitro and in vivo partially through acetylation of p53

Background: Histone deacetylase (HDAC) inhibitors have emerged as a new class of anti-tumor agents for various types of tumors, including glioblastoma.

Methods and results: We found that a novel HDAC inhibitor, MPT0B291, significantly reduced the cell viability and increased cell death of human and rat glioma cell lines, but not in normal astrocytes. We also demonstrated that MPT0B291 suppressed proliferation by inducing G1 phase cell cycle arrest and increased apoptosis in human and rat glioma cell lines by flow cytometry and immunocytochemistry. We further investigated the anti-tumor effects of MPT0B291 in xenograft (mouse) and allograft (rat) models. The IVIS200 images and histological analysis indicated MPT0B291 (25 mg/kg, p. o.) reduced tumor volume. Mechanistically, MPT0B291 increased phosphorylation and acetylation/activation of p53 and increased mRNA levels of the apoptosis related genes PUMA, Bax, and Apaf1 as well as increased protein level of PUMA, Apaf1 in C6 cell line. The expression of cell cycle related gene p21 was also increased and Cdk2, Cdk4 were decreased by MPT0B291.

Conclusion: Our study highlights the anti-tumor efficacy of a novel compound MPT0B291 on glioma growth.

Mechanisms and therapeutic potentials of cancer immunotherapy in combination with radiotherapy and/or chemotherapy

Immunotherapies based on T cells have gained significant success in the treatment of diverse cancers, however, several limitations also exist, including low response, acquired resistance and severe side effects, which lead to unfavorable outcomes. Recent studies found that traditional therapies, radiotherapy and/or chemotherapy may affect the immune condition in situ and cause abscopal effect, which may improve the response of immunotherapies, enhance the efficiency, and reduce the untoward effect. Here, we review the mechanisms uncovering the cancer immunotherapy and immunogenic effects of radiotherapy and chemotherapy, aiming to highlight the principles underlying the therapeutic potentials of cancer immunotherapy in combination with radiotherapy and/or chemotherapy and ultimately guide better designs for future synergistic cancer therapies.

Cancer Stem Cells and Immunosuppressive Microenvironment in Glioma

Glioma is one of the most common malignant tumors of the central nervous system and is characterized by extensive infiltrative growth, neovascularization, and resistance to various combined therapies. In addition to heterogenous populations of tumor cells, the glioma stem cells (GSCs) and other nontumor cells present in the glioma microenvironment serve as critical regulators of tumor progression and recurrence. In this review, we discuss the role of several resident or peripheral factors with distinct tumor-promoting features and their dynamic interactions in the development of glioma. Localized antitumor factors could be silenced or even converted to suppressive phenotypes, due to stemness-related cell reprogramming and immunosuppressive mediators in glioma-derived microenvironment. Furthermore, we summarize the latest knowledge on GSCs and key microenvironment components, and discuss the emerging immunotherapeutic strategies to cure this disease.

Perspectives for cancer immunotherapy mediated by p19Arf plus interferon-beta gene transfer

While cancer immunotherapy has gained much deserved attention in recent years, many areas regarding the optimization of such modalities remain unexplored, including the development of novel approaches and the strategic combination of therapies that target multiple aspects of the cancer-immunity cycle. Our own work involves the use of gene transfer technology to promote cell death and immune stimulation. Such immunogenic cell death, mediated by the combined transfer of the alternate reading frame (p14ARF in humans and p19Arf in mice) and the interferon-β cDNA in our case, was shown to promote an antitumor immune response in mouse models of melanoma and lung carcinoma. With these encouraging results, we are now setting out on the road toward translational and preclinical development of our novel immunotherapeutic approach. Here, we outline the perspectives and challenges that we face, including the use of human tumor and immune cells to verify the response seen in mouse models and the incorporation of clinically relevant models, such as patient-derived xenografts and spontaneous tumors in animals. In addition, we seek to combine our immunotherapeutic approach with other treatments, such as chemotherapy or checkpoint blockade, with the goal of reducing dosage and increasing efficacy. The success of any translational research requires the cooperation of a multidisciplinary team of professionals involved in laboratory and clinical research, a relationship that is fostered at the Cancer Institute of Sao Paulo.

Trial Watch: Immunostimulation with recombinant cytokines for cancer therapy

Cytokines regulate virtually aspects of innate and adaptive immunity, including the initiation, execution and extinction of tumor-targeting immune responses. Over the past three decades, the possibility of using recombinant cytokines as a means to elicit or boost clinically relevant anticancer immune responses has attracted considerable attention. However, only three cytokines have been approved so far by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, namely, recombinant interleukin (IL)-2 and two variants of recombinant interferon alpha 2 (IFN-α2a and IFN-α2b). Moreover, the use of these cytokines in the clinics is steadily decreasing, mostly as a consequence of: (1) the elevated pleiotropism of IL-2, IFN-α2a and IFN-α2b, resulting in multiple unwarranted effects; and (2) the development of highly effective immunostimulatory therapeutics, such as immune checkpoint blockers. Despite this and other obstacles, research in the field continues as alternative cytokines with restricted effects on specific cell populations are being evaluated. Here, we summarize research preclinical and clinical developments on the use of recombinant cytokines for immunostimulation in cancer patients.

Translational gap in ongoing clinical trials for glioma

Despite the vast amounts of information gathered about gliomas, the overall survival of glioma patients has not improved in the last four decades. This could partially be due to an apparent failure to include basic concepts of glioma biology into clinical trials. Specifically, attempts to overcome the limitations of the blood brain barrier (BBB) and the chemoresistance of glioma stem cells (GSCs) were seldom included (a phenomenon known as the translational gap, TG) in a study involving 29 Phase I/II clinical trials (P2CT) published in 2011. The aim of this study was to re-evaluate this finding with a new series of 100 ongoing, but still unpublished, P2CT in order to determine if there is a TG reduction. As indicators, we evaluated in each P2CT the number of drugs tested, concomitant radiotherapy, and the ability of drugs to pass the BBB and to target GSCs. Compared to clinical trials published in 2011, we found that while in OCT there is an increase in the number of P2CT using two drugs (from 24.1% to 44.9%), and an increase in the number of drugs able to pass the BBB (7.14% versus 64.29%) and target GSCs (0% versus 16.3%), there was a decrease in the number of P2CT using concomitant radiotherapy (34.5% versus 18.37%). Overall our results suggest that there is only a modest improvement regarding reducing the TG because the vast majority of ongoing P2CT are still not including well known concepts of glioma biology important for a successful treatment.

CNS metastasis secondary to malignant-mixed Müllerian tumor: case report and review of therapeutics

This paper reviews CNS involvement secondary to malignant-mixed Müllerian tumor or uterine carcinosarcoma, a rare aggressive biphasic Müllerian tumor. We report a cerebellar metastasis with epithelial and mesenchymal components, demonstrating heterologous rhabdomyogenic and chondroblastic differentiation. The patient had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy for palliation of symptomatic chemotherapy-resistant node-positive disease. CNS involvement is rare, and prognostically poor, and suggestively poorer in predominantly sarcomatous metastases. Multimodal therapy is indicated; in solitary metastases, surgical resection or stereotactic radiosurgery is included, followed by whole brain radiotherapy. In unresectable brain metastases, stereotactic radiosurgery and whole brain radiotherapy warrant consideration in up to 2-3 metastases. In multiple metastases, palliative steroid therapy or cranial irradiation may be considered. Combination or platinum-based chemotherapy (i.e., ifosfamide-paclitaxel or carboplatin-paclitaxel) is indicated in all stages, with a role in both disease cure and control-directed management. Targeted therapeutics have thus far not demonstrated significant clinical efficacy.