Treatment Of Malignant Gliomas Research Articles

ACT-8 Current status and prospects for the treatment of malignant glioma using cancer gene panel tests

Introduction: The cancer gene panel test was covered by insurance in June 2019. Our institution started the test in May 2020 and has experienced 10 cases, so we will report on the current status and future prospects. Methods: The subjects were 10 patients who underwent the cancer gene panel test using FoundationOne CDx. Results:The cases included 8 glioblastomas, an anaplastic astrocytoma, and an anaplastic oligodendroglioma. The total number of tumor mutational burden (TMB) was judged to be low in all cases, and the microsatellite instability test (MSI) showed no instability in all cases (MSI-Stable). The total number of genetic changes detected was 11 ± 5.0, oncogene mutations were 5.3 ± 2.4, and gene mutations of unknown relevance to cancer were 5.7 ± 2.8. Major oncogene mutations were IDH1 mutation in 4 cases, ATRX mutation in 2 cases, TP53 mutation in 6 cases, and BRAF V600E mutation in 1 case. Based on the test results, a 25-year-old man with BRAF V600E mutation was initiated into the NCCH1901 study (Patient-Proposed Healthcare Services). A case with IDH1 mutation (47-year-old male) entered a phase I clinical trial of a mutant IDH1 inhibitor. It is estimated that the chance of finding an appropriate drug by cancer gene panel test is about 10–20%. However, in cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used. Conclusions: Although Malignant gliomas are often TMB-low and MSI-stable and the response rate to molecular-targeted drugs and other therapies is not high, there are some cases that can be salvaged by performing the cancer gene panel test. It is suggested that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.

Boron delivery agents for boron neutron capture therapy

<p indent=0mm>Boron neutron capture therapy (BNCT) is a binary method of radiotherapy, which is based on the nuclear reaction that occurs when boron-10 is irradiated with thermal neutron to yield high linear energy transfer α particles and recoiling lithium-7 nuclei. These particles with high energy and short range can kill cancer cells which absorbed ¹⁰B while little damage to normal tissues. BNCT has experienced nearly <sc>90 years</sc> of development since it was first proposed in 1936, which is one of the most effective methods for the treatment of malignant glioma. One of the key factors for the success of BNCT is to find boron delivery agents with high targeting and high affinity to tumors. Currently, although there are various of boron delivery agents, the best compound recognized for BNCT is still boronophenylalanine (BPA), for it has little side effect and no chemistry toxicity. BPA can penetrate the BBB and cell membrane, so it owns higher relative biological effectiveness. BPA is the most widely used BNCT drug in the world, which was officially approved in Japan last year, and the therapeutic effect on glioma is without question. In the past few decades, in order to improve the efficacy of BNCT, significant effort has been devoted to developing new boron delivery agents that possess better uptake and favorable pharmacokinetic characteristics for clinical use. This review focuses on differents kinds of boron delivery agents developed over the past years, which can be divided into three generations. At present, the first generation of boron delivery agents has been banned for lacking of targeting. The second generation of boron delivery agents is the most mature of the clinical application, but there are some problems need to be solved, such as limited boron loading and individual uptake varies greatly. The third generation of boron delivery agents contains various of agents—The boron-containing amino acids and peptides, the boron-containing compound conjugated with nucleosides, porphyrin derivatives, and different types of nanomaterials, was introduced in detail in this review. The boron loading and targeting of the third generation of boron delivery agents have greatly increased, but most of them are still in the experimental stage, and the safety and effectiveness need to be further verified. The advantages and disadvantages of the three generation boron delivery agents were analyzed and compared. Meanwhile the limitations of the various boron delivery agents were discussed and summarized. Additionally, the prospect and bottleneck of clinical arpplication of these boron delivery agents was critically analyzed from different view of research institutions, pharmaceutical enterprises and government policy. And the corresponding solutions were proposed: (1) Expand the application scope of BPA and BSH; develop new drugs and expand the application fields of BNCT technology; (2) enhance the cooperation of enterprises, university and research institutions, and promote the clinical approval and application of BPA and BSH; (3) multi disciplines jointly overcome technical barriers and establish a perfect evaluation system of safety and effectiveness for BNCT. In summary, with the official approval of the Japanese accelerator BNCT treatment system, the application prospects of BNCT technology will be broad all over the world. The comprehensive research of BNCT technology will be promoted by enhancing the intercrossing and coalescence between subjects relative with BNCT, and new ideas will be inspired, all of which will promote the clinical application of BNCT technology, and that benefit patients.

Preliminary Report: Rapid Intraoperative Detection of Residual Glioma Cell in Resection Cavity Walls Using a Compact Fluorescence Microscope.

Objective: The surgical eradication of malignant glioma cells is theoretically impossible. Therefore, reducing the number of remaining tumor cells around the brain–tumor interface (BTI) is crucial for achieving satisfactory clinical results. The usefulness of fluorescence–guided resection for the treatment of malignant glioma was recently reported, but the detection of infiltrating tumor cells in the BTI using a surgical microscope is not realistic. Therefore, we have developed an intraoperative rapid fluorescence cytology system, and exploratorily evaluated its clinical feasibility for the management of malignant glioma. Materials and methods: A total of 25 selected patients with malignant glioma (newly diagnosed: 17; recurrent: 8) underwent surgical resection under photodiagnosis using photosensitizer Talaporfin sodium and a semiconductor laser. Intraoperatively, a crush smear preparation was made from a tiny amount of tumor tissue, and the fluorescence emitted upon 620/660 nm excitation was evaluated rapidly using a compact fluorescence microscope in the operating theater. Results: Fluorescence intensities of tumor tissues measured using a surgical microscope correlated with the tumor cell densities of tissues evaluated by measuring the red fluorescence emitted from the cytoplasm of tumor cells using a fluorescence microscope. A “weak fluorescence” indicated a reduction in the tumor cell density, whereas “no fluorescence” did not indicate the complete eradication of the tumor cells, but indicated that few tumor cells were emitting fluorescence. Conclusion: The rapid intraoperative detection of fluorescence from glioma cells using a compact fluorescence microscope was probably useful to evaluate the presence of tumor cells in the resection cavity walls, and could provide surgical implications for the more complete resection of malignant gliomas.

IMMU-30. IDENTIFICATION OF COORDINATELY REGULATED IMMUNO-MODULATORY GENES USING SINGLE-CELL RNA SEQUENCING OF DECITABINE TREATED GLIOMA CELLS

Abstract INTRODUCTION The immunotherapeutic targeting of New York-esophageal squamous cell carcinoma (NY-ESO-1) and other cancer/testis antigens (CTA) is an appealing strategy for the treatment of malignant gliomas because CTA are not expressed in most normal adult tissues and their expression can be induced in tumors for targeting by T-cells. Basally, NY-ESO-1 is often poorly expressed in glioblastoma (GBM), presumably through promoter methylation. Our previous data has shown that the hypomethylating agent decitabine (DAC) is a strong sensitizer of GBM to NY-ESO-1 specific adoptive T-cell induced cytotoxicity. However, we hypothesized that DAC alters expression of other immuno-modulatory genes in addition to NY-ESO-1 that may also increase T-cell mediated killing in GBM. The extent of regulation of other immuno-modulatory genes to DAC demethylation has not yet been thoroughly investigated. METHODS We performed single-cell RNA sequencing on DAC and non-DAC treated glioma cells. We confirmed DAC treatment induced NY-ESO-1 expression with quantitative real-time PCR and demethylation using bisulfite sequencing. We analyzed our single-cell RNA sequencing data with Seurat and our customized R-based pipelines to identify coordinate differential expression of immuno-modulatory genes and their tumor subpopulations. RESULTS Using our single-cell data, we identified tumor subpopulations with coordinate differentially expressed immuno-modulatory genes including cancer testes antigens, antigen presentation proteins, and apoptosis regulators. Amongst these candidate genes, we validated their expression with qPCR and promoter demethylation with bisulfite sequencing and TA bisulfite cloning. CONCLUSION Exposure of glioma cells to DAC results in promoter demethylation of NY-ESO-1, with increased expression of CTA and other immunomodulatory genes. DAC treatment may therefore sensitize GBM to the immunotherapeutic targeting of these antigens and reveals a feasible strategy for clinical translation.

Chronic pathophysiological changes in the normal brain parenchyma caused by radiotherapy accelerate glioma progression

Radiation therapy is one of standard treatment for malignant glioma after surgery. The microenvironment after irradiation is considered not to be suitable for the survival of tumor cells (tumor bed effect). This study investigated whether the effect of changes in the microenvironment of parenchymal brain tissue caused by radiotherapy affect the recurrence and progression of glioma. 65-Gy irradiation had been applied to the right hemisphere of Fisher rats. After 3 months from irradiation, we extracted RNA and protein from the irradiated rat brain. To study effects of proteins extracted from the brains, we performed WST-8 assay and tube formation assay in vitro. Cytokine production were investigated for qPCR. Additionally, we transplanted glioma cell into the irradiated and sham animals and the median survival time of F98 transplanted rats was also examined in vivo. Immunohistochemical analyses and invasiveness of implanted tumor were evaluated. X-ray irradiation promoted the secretion of cytokines such as CXCL12, VEGF-A, TGF-β1 and TNFα from the irradiated brain. Proteins extracted from the irradiated brain promoted the proliferation and angiogenic activity of F98 glioma cells. Glioma cells implanted in the irradiated brains showed significantly high proliferation, angiogenesis and invasive ability, and the post-irradiation F98 tumor-implanted rats showed a shorter median survival time compared to the Sham-irradiation group. The current study suggests that the microenvironment around the brain tissue in the chronic phase after exposure to X-ray radiation becomes suitable for glioma cell growth and invasion.

Oncolytic Viro-Immunotherapy: An Emerging Option in the Treatment of Gliomas

The prognosis of malignant gliomas remains poor, with median survival fewer than 20 months and a 5-year survival rate merely 5%. Their primary location in the central nervous system (CNS) and its immunosuppressive environment with little T cell infiltration has rendered cancer therapies mostly ineffective, and breakthrough therapies such as immune checkpoint inhibitors (ICIs) have shown limited benefit. However, tumor immunotherapy is developing rapidly and can help overcome these obstacles. But for now, malignant gliomas remain fatal with short survival and limited therapeutic options. Oncolytic virotherapy (OVT) is a unique antitumor immunotherapy wherein viruses selectively or preferentially kill tumor cells, replicate and spread through tumors while inducing antitumor immune responses. OVTs can also recondition the tumor microenvironment and improve the efficacy of other immunotherapies by escalating the infiltration of immune cells into tumors. Some OVTs can penetrate the blood-brain barrier (BBB) and possess tropism for the CNS, enabling intravenous delivery. Despite the therapeutic potential displayed by oncolytic viruses (OVs), optimizing OVT has proved challenging in clinical development, and marketing approvals for OVTs have been rare. In June 2021 however, as a genetically engineered OV based on herpes simplex virus-1 (G47Δ), teserpaturev got conditional and time-limited approval for the treatment of malignant gliomas in Japan. In this review, we summarize the current state of OVT, the synergistic effect of OVT in combination with other immunotherapies as well as the hurdles to successful clinical use. We also provide some suggestions to overcome the challenges in treating of gliomas.

Accurately Controlled Delivery of Temozolomide by Biocompatible UiO-66-NH2 Through Ultrasound to Enhance the Antitumor Efficacy and Attenuate the Toxicity for Treatment of Malignant Glioma.

BackgroundGlioma is the most common and malignant primary brain tumour in adults and has a dismal prognosis. Temozolomide (TMZ) is the only clinical first-line chemotherapy drug for malignant glioma up to present. Due to poor aqueous solubility and toxic effects, TMZ is still inefficient and limited for clinical glioma treatment.MethodsUiO-66-NH2 nanoparticle is a zirconium-based framework, constructed by Zr and 2-amino-1,4-benzenedicarboxylic acid (BDC-NH2) with octahedral microporous structure, which can be decomposed by the body into an ionic form to discharge. We prepared the nanoscale metal-organic framework (MOF) of UiO-66-NH2 to load TMZ for therapy of malignant glioma, TMZ is released from UiO-66-NH2 through a porous structure. The ultrasound accelerates its porous percolation and promotes the rapid dissolution of TMZ through low-frequency oscillations and cavitation effect. The biological safety and antitumor efficacy were evaluated both in vitro and in vivo.ResultsThe prepared TMZ@MOF exhibited excellent biocompatibility and biosafety due to minimal drug leakage without ultrasound intervention. We further used the flank model of glioblastoma to verify the in vivo therapeutic effect. TMZ@UiO-66-NH2 nanocomposites could be well delivered to the tumour tissue, which led to local enrichment of the TMZ concentration. Furthermore, TMZ@UiO-66-NH2 nanocomposites under ultrasound demonstrated much more efficient inhibition for tumor growth than TMZ@UiO-66-NH2 nanocomposites and TMZ alone. Meanwhile, the bone marrow suppression side effects of TMZ were significantly reduced by TMZ@UiO-66-NH2 nanocomposites.ConclusionIn this work, TMZ@UiO-66-NH2 nanocomposites with ultrasound mediation could effectively improve the killing effect of malignant glioma and decrease TMZ-induced toxicity in normal tissues, demonstrating great potential for the delivery of TMZ in the clinical treatment of malignant gliomas.

Hyperintense signal on diffusion-weighted imaging for monitoring the acute response and local recurrence after photodynamic therapy in malignant gliomas.

Photodynamic therapy (PDT) subsequent to surgical tumor removal is a novel localized treatment for malignant glioma that provides effective local control. The acute response of malignant glioma to PDT can be detected as linear transient hyperintense signal on diffusion-weighted imaging (DWI) and a decline in apparent diffusion coefficient values without symptoms. However, their long-term clinical significance has not yet been examined. The aim of this study was to clarify the link between hyperintense signal on DWI as an acute response and recurrence after PDT in malignant glioma. Thirty patients (16 men; median age, 60.5 years) underwent PDT for malignant glioma at our institution between 2017 and 2020. We analyzed the signal changes on DWI after PDT and the relationship between these findings and the recurrence pattern. All patients showed linear hyperintense signal on DWI at the surface of the resected cavity from day 1 after PDT. These changes disappeared in about 30 days without any neurological deterioration. During a mean post-PDT follow-up of 14.3 months, 19 patients (63%) exhibited recurrence: 10 local, 1 distant, and 8 disseminated. All of the local recurrences arose from areas that did not show hyperintense signal on DWI obtained on day 1 after PDT. The local recurrence in malignant glioma after PDT occurs in an area without hyperintense signal on DWI as an acute response to PDT. This characteristic finding could aid in the monitoring of local recurrence after PDT.

PL03.1.A Surgery for glioblastomas in the elderly: an ANOCEF trial (CSA)

Abstract BACKGROUND The role of surgery for the treatment of malignant gliomas in patients 70 years of age or older is unsettled. We conducted a randomized trial that compared surgical resection of the tumor and biopsy only, both followed by standard therapy, in such patients. MATERIAL AND METHODS Patients aged 70 years and older, with a KPS of at least 50, presenting with a radiological suspicion of an operable glioblastoma (GBM) were randomly assigned between tumor resection and biopsy. Subsequently, they underwent standard radiotherapy during the first years of the trial (2008–2017), with the adjunction of concomitant and adjuvant temozolomide when this regimen became standard (2017–2019). The primary end point was survival; secondary endpoints were progression free survival (PFS), cognitive status (MMS), autonomy (KPS), quality of life (EORTC QLQ C30 and BN20), and perioperative morbidity/ mortality. RESULTS From 2008 to 2019, 107 patients from 9 centers were enrolled in the study, of whom 101 were evaluable for analysis because the diagnosis of GBM was histologically confirmed (50 patients in the “surgery” arm and 51 patients in the “biopsy” arm). There was no statistically significant difference of median survival between the “surgery” arm (9.37 mo) and the “biopsy” arms (8.96 mo, p=0.36). However, the surgery group had increased PFS (5.06 mo vs 4.02 mo; p=0.034; p=0.002 on multivariate analysis) and better QOL (e.g. physical and cognitive functioning, motor dysfunction, fatigue) and KPS score evolution as compared to the “biopsy” group. Surgery was not associated with increased mortality or morbidity. CONCLUSION This study suggests that optimal debulking surgery does not provide a significant survival benefit in elderly patients suffering from newly diagnosed malignant glioma, but resection improves QOL and autonomy with a significant though modest improvement of PFS.

In Vitro and In Vivo Enhancement of Temozolomide Effect in Human Glioblastoma by Non-Invasive Application of Cold Atmospheric Plasma.

Simple SummaryGlioblastoma (GBM) is an aggressive type of brain cancer, with which only 25% of patients survive for more than one year. Treatment of GBM has remained a challenge due to its resistance to chemotherapy. Here, we aimed to assess the potential for a combination therapy of cold atmospheric plasma (CAP) and Temozolomide (TMZ) to treat GBM. We confirmed the effect of co-treatment on different GBM cell lines in vitro and determined the enhancement of the effect of TMZ and the potential sensitization of GBM to CAP + TMZ in murine models in vivo. We found that co-treatment with CAP + TMZ inhibited GBM significantly compared to single treatment with CAP or TMZ alone. We provided further evidence related to the bone penetration of reactive oxygen and nitrogen species, as well as electromagnetic waves generated by CAP. RNA sequencing further indicated an effect of CAP + TMZ on cell cycle pathways. Collectively, these findings point to potential non-invasive translational approaches to target GBM in the future.Glioblastoma (GBM) is one of the most aggressive forms of adult brain cancers and is highly resistant to treatment, with a median survival of 12–18 months after diagnosis. The poor survival is due to its infiltrative pattern of invasion into the normal brain parenchyma, the diffuse nature of its growth, and its ability to quickly grow, spread, and relapse. Temozolomide is a well-known FDA-approved alkylating chemotherapy agent used for the treatment of high-grade malignant gliomas, and it has been shown to improve overall survival. However, in most cases, the tumor relapses. In recent years, CAP has been used as an emerging technology for cancer therapy. The purpose of this study was to implement a combination therapy of CAP and TMZ to enhance the effect of TMZ and apparently sensitize GBMs. In vitro evaluations in TMZ-sensitive and resistant GBM cell lines established a CAP chemotherapy enhancement and potential sensitization effect across various ranges of CAP jet application. This was further supported with in vivo findings demonstrating that a single CAP jet applied non-invasively through the skull potentially sensitizes GBM to subsequent treatment with TMZ. Gene functional enrichment analysis further demonstrated that co-treatment with CAP and TMZ resulted in a downregulation of cell cycle pathway genes. These observations indicate that CAP can be potentially useful in sensitizing GBM to chemotherapy and for the treatment of glioblastoma as a non-invasive translational therapy.

MiRNA-451 regulates the NF-κB signaling pathway by targeting IKKβ to inhibit glioma cell growth

ABSTRACT Glioblastoma multiforme (GBM) is associated with a poor prognosis, and effective treatments are lacking. Our previous studies have shown that miRNA-451 is closely related to the development and progression of glioma. miRNA-451 is a tumor suppressor whose expression is negatively correlated with the WHO grades of gliomas, but its specific mechanism is still unclear. Research shows that NF-κB is highly expressed in early malignant glioma, and thus, the NF-κB signaling pathway has become an important target for the treatment of malignant glioma. Activation of IKK is a critical step in the activation of the classical NF-κB pathway. By performing a bioinformatics analysis, we found that IKKβ is a potential direct target of miRNA-451 in glioma. In this study, we transfected lentivirus expressing miRNA-451 to test the effect of miRNA-451 overexpression on malignant glioma cell lines and confirmed that IKKβ is a target gene of miRNA-451 by luciferase assay. By targeting IKKβ, MTT, cell invasion and wound-healing assays showed that cell proliferation, cell invasion and migration were significantly suppressed in the LV-miRNA-451 group. Western blotting results showed that the expression levels of IKKβ, p-p65, MMP-2, MMP-9, Cyclin D1, p16 and PCNA were significantly decreased in the LV-miRNA-451 group. In vivo, miRNA-451 significantly decreased glioma cell growth, and the survival of BALB/c-A nude mice was significantly prolonged. Immunohistochemistry showed that p-p65, Cyclin D1 and Ki67 expression was significantly reduced in the LV-miRNA-451 group. Taken together, these results suggest that miRNA-451 could regulate the NF-κB signaling pathway by targeting IKKβ, which inhibits glioma cell growth in vitro and in vivo. Therefore, this study may provide novel insight into miRNA-451-targeted therapy for glioma.

ECOA-2. Immuno-sensitization of Glioblastoma to NY-ESO-1 Targeting via Promoter Demethylation

Abstract Introduction The immunotherapeutic targeting of New York-esophageal squamous cell carcinoma (NY-ESO-1) and other cancer/testis antigens (CTA) is an appealing strategy for the treatment of malignant gliomas because CTA are not expressed in most normal adult tissues and their expression can be induced in tumors for targeting by T-cells. Basally, NY-ESO-1 is often poorly expressed in glioblastoma (GBM), presumably through promoter methylation. Mechanisms governing the expression of CTA have been explored in other cancers; however, neither the prevalence of NY-ESO-1 downregulation in GBM patient tumors nor the presumed mechanism of downregulation by promoter methylation in GBM has been formally established. Methods We characterized baseline CpG methylation of NY-ESO-1 in 30 bulk patient GBM samples, 10 patient-derived gliomaspheres, and three established tumor cell lines using bisulfite sequencing. We induced NY-ESO-1 expression in vitro in U251 human GBM cells using the hypomethylating agent decitabine (DAC). We investigated the epigenetic response of DAC-treated U251 with bisulfite sequencing and NY-ESO-1 expression with quantitative real-time PCR. Lastly, we performed single-cell RNA sequencing on DAC-treated GBM U251 to evaluate tumor subpopulations that upregulate NY-ESO-1 and other co-expressed CTA after DAC treatment. Results Baseline NY-ESO-1 expression is associated with promoter methylation in the majority of GBM. Treatment of cells with 1 µM DAC every day for 4 days explicitly demethylated the promoter region of NY-ESO-1 and resulted in a 1000-fold increase in mRNA expression. DAC treatment upregulates NY-ESO-1 coordinately with other cancer/testis antigens CTAG2 and MAGEA4 as demonstrated by single-cell RNA sequencing. Conclusion Exposure of U251 to DAC results in promoter demethylation in NY-ESO-1 and increased expression of CTA. DAC treatment may therefore render GBM susceptible to targeting of these antigens by T-cells, revealing a feasible strategy of NY-ESO-1 and co-expressed CTA promoter demethylation to sensitize GBM to immunotherapy.

Abstract 1948: Investigation of the effect of LLLT on glioblastoma multiforme

Abstract Low-level Laser Treatment (LLLT) has a potential to alter tumor behavior such as proliferation in addition to therapeutic effects such as wound healing, inflammation reduction. Studies indicate that, different tumor cells respond distinctly to LLLT based on laser dose (J/sq. cm). GBM is an aggressive and invasive primary brain tumor which is heterogenic in nature and any treatment that could have a potential to kill or change tumor behavior or tumor microenvironment by making GBM sensitive to available treatments can help improve the survival rate. In this study, we investigated the effect of LLLT on human malignant glioma (U251) cells using He-Ne Laser (632.8 nm). The He-Ne laser parameters used for the treatment are power (14.87±0.3 mW), beam diameter (0.68 cm), and varying laser exposure times of 5 mins and 10 mins leading to variable doses of 12.28 J/sq.cm and 24.56 J/sq. cm respectively. The dose response of LLLT on U251 cells revealed that the dose 12.28 J/sq. cm lead to cell death of 17%, 24 hrs post treatment while the dose 24.56 J/sq. cm achieved cell death of 30%, 6 hrs post treatment along with some morphological changes such as vacuole formation in the heterogenic malignant glioma. Also, a biphasic response was observed post treatment with the dose of 24.56 J/sq. cm, as we observed increase in cell viability 18hrs post treatment along with neurite formation. Western analysis suggests the involvement of PARP and caspase 9 in killing LLL treated U251 cells. Thus, upon further study, LLLT could have a potential to be used as an adjunctive treatment when used with conventional treatments for malignant glioma. Citation Format: Rohini Atluri, Parsa Afkhami, Tae-Youl Choi, Denise P. Simmons. Investigation of the effect of LLLT on glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1948.

Role of Polymeric Local Drug Delivery in Multimodal Treatment of Malignant Glioma: A Review.

Malignant gliomas (MGs) are the most common and devastating primary brain tumor. At present, surgical interventions, radiotherapy, and chemotherapy are only marginally effective in prolonging the life expectancy of patients with MGs. Inherent heterogeneity, aggressive invasion and infiltration, intact physical barriers, and the numerous mechanisms underlying chemotherapy and radiotherapy resistance contribute to the poor prognosis for patients with MGs. Various studies have investigated methods to overcome these obstacles in MG treatment. In this review, we address difficulties in MG treatment and focus on promising polymeric local drug delivery systems. In contrast to most local delivery systems, which are directly implanted into the residual cavity after intratumoral injection or the surgical removal of a tumor, some rapidly developing and promising nanotechnological methods—including surface-decorated nanoparticles, magnetic nanoparticles, and focused ultrasound assist transport—are administered through (systemic) intravascular injection. We also discuss further synergistic and multimodal strategies for heightening therapeutic efficacy. Finally, we outline the challenges and therapeutic potential of these polymeric drug delivery systems.

Radiation-induced YAP activation confers glioma radioresistance via promoting FGF2 transcription and DNA damage repair

Although radiotherapy is a well-known effective non-surgical treatment for malignant gliomas, the therapeutic efficacy is severely limited due to the radioresistance of tumor cells. Previously, we demonstrated that Yes-associated protein (YAP) promotes glioma malignant progression. However, whether YAP plays a role in radioresistance and its potential value in cancer treatment are still unclear. In this study, we found that high YAP expression is associated with poor prognosis in malignant glioma patients undergoing radiotherapy. Research in immortalized cell lines and primary cells from GBM patients revealed that YAP exhibited a radioresistant effect on gliomas via promoting DNA damage repair. Mechanistically, after radiation, YAP was translocated into the nucleus, where it promoted the expression and secretion of FGF2, leading to MAPK–ERK pathway activation. FGF2 is a novel target gene of YAP. Inhibition of YAP–FGF2–MAPK signaling sensitizes gliomas to radiotherapy and prolongs the survival of intracranial cell-derived and patient-derived xenograft models. These results suggest that YAP–FGF2–MAPK is a key mechanism of radioresistance and is an actionable target for improving radiotherapy efficacy.

Evaluation of surgical resection combined with interstitial sustained-release chemotherapy in the treatment of recurrent malignant gliomas.

article: Evaluation of surgical resection combined with interstitial sustained-release chemotherapy in the treatment of recurrent malignant gliomas - Panminerva Medica 2021 Jun 11 - Minerva Medica - Journals

Effect of temozolomide combined with radiotherapy on survival and MGMT protein expression in recurrent malignant glioma patients

Purpose: To investigate the effect of temozolomide (TMZ) combined with radiotherapy (RT) on O-6- methylguanine-DNA methyltransferase (MGMT) protein and survival of recurrent malignant glioma patients.&#x0D; Methods: Ninety-two patients with malignant glioma in our hospital from January 2014 to January 2015 were assigned to study and control groups using the random table method. Subjects in the control group received radiotherapy (total dose in the range of 60 – 75 Gy), while those in the study group were given TMZ orally (75 mg/m2) daily in addition to radiotherapy, as well as TMZ at 150 – 200 mg/m2. After treatment, clinical effectiveness was compared for the two groups. Changes in methylation of MGMT gene were determined in the two groups. The patients were followed up for 3 years, and the degrees of survival and recurrence were recorded.&#x0D; Results: Total effectiveness of clinical treatment was markedly higher in the study group (76.09 %) than in the control group (45.65 %; p &lt; 0.05). One month after radiotherapy, significant decrease in MGMT gene methylation was seen in patients in the study group, relative to control patients (p &lt; 0.05). Patients in the study group had lower median recurrence but higher degree of survival in the 2nd and 3rd years, relative to control patients (p &lt; 0.05).&#x0D; Conclusion: The combination of temozolomide and radiotherapy is more effective than radiotherapy in the treatment of recurrent malignant glioma. The combined treatment significantly inhibits tumor recurrence in patients, and improves their prognosis and standard of life.

Chemotherapy for Glioma

Chemotherapeutic treatment of malignant gliomas is extremely challenging. Tumor accumulation of systemically-administrated chemotherapy is always hindered by the blood-brain barrier(BBB). Although temozolomide administered orally or intravenously represents the standard of care for malignant gliomas, its efficacy is unsatisfactory. Local chemotherapy bypasses the BBB and, therefore, achieves a high drug concentration at the site the drug is administered. Carmustine wafers are clinically available local chemotherapeutic agents. However, their efficacy is limited because of limited drug penetration into the tumor. Combined with the highly chemoresistant features of glioma itself, ongoing chemotherapy is far from satisfactory in terms of efficacy. This review covers several important issues regarding temozolomide chemotherapy, including the reactivation of hepatitis B virus, assessment of MGMT promoter methylation, and pseudo-progression. Local chemotherapy for newly diagnosed resectable glioblastoma cases using carmustine wafers is currently under investigation with a randomized phase 3 trial (JCOG 1703), which will also be discussed. In addition, recent progress in convection-enhanced delivery of chemotherapeutics against gliomas has also been reported. Development of an alternative strategy to effectively deliver drugs to the tumor site may improve the efficacy of chemotherapy against gliomas in the near future.

Targeting the Complement Pathway in Malignant Glioma Microenvironments

Malignant glioma is a highly fatal type of brain tumor, and its reoccurrence is largely due to the ordered interactions among the components present in the complex microenvironment. Besides its role in immune surveillance and clearance under physiological conditions, the complement system is expressed in a variety of tumor types and mediates the interactions within the tumor microenvironments. Recent studies have uncovered the broad expression spectrum of complement signaling molecules in the tumor microenvironment and various tumor cells, in particular, malignant glioma cells. Involvement of the complement system in tumor growth, immunosuppression and phenotype transition have also been elucidated. In this review, we enumerate the expression and function of complement molecules in multiple tumor types reported. Moreover, we elaborate the complement pathways in glioma cells and various components of malignant glioma microenvironments. Finally, we summarize the possibility of the complement molecules as prognostic factors and therapeutic targets in the treatment of malignant glioma. Specific targeting of the complement system maybe of great significance and value in the future treatment of multi-type tumors including malignant glioma.

Inflammatory tumor microenvironment responsive neutrophil exosomes-based drug delivery system for targeted glioma therapy

Clinical treatment of malignant glioma remains a major challenge due to high infiltrative growth and chemotherapeutic resistance of tumors and the presence of the blood brain barrier (BBB). Advanced nanoplatforms that can efficiently cross the BBB and target to brain tumor are urgently needed. Encouraged by the intrinsic inflammatory chemotaxis and excellent BBB-crossing capability of neutrophils, a bioinspired neutrophil-exosomes (NEs-Exos) system for delivering loaded doxorubicin (DOX) drug for glioma treatment is proposed and systematically investigated. In vivo zebrafish and C6-Luc glioma-bearing mice models show that NEs-Exos carrying the drug rapidly penetrate the BBB and migrate into the brain. Additionally, a transwell BBB model and mouse brain inflammatory study show that NEs-Exos can respond chemotactically to inflammatory stimuli and target infiltrating tumor cells in inflamed brain tumors. Moreover, intravenous injection of NEs-Exos/DOX efficiently suppress tumor growth and prolong survival time in a glioma mouse model. On the basis of these results, NEs-Exos are confirmed to have neutrophil-like chemotactic function and BBB penetration. This novel NEs-Exos/DOX delivery platform represents a promising chemotherapeutic approach for clinical treatment of glioma and other solid tumor or brain diseases.