Temozolomide is additive with cytotoxic effect of irradiation in canine glioma cell lines

BACKGROUND

Similar to human glioblastoma patients, glial tumours in dogs have high treatment resistance and a guarded prognosis. In human medicine, the addition of temozolomide to radiotherapy leads to a favourable outcome in vivo as well as a higher antiproliferative effect on tumour cells in vitro.

OBJECTIVES

The aim of the study was to determine the radio- and temozolomide-sensitivity of three canine glial tumour cell lines and to investigate a potential additive cytotoxic effect in combined treatment. Additionally, we wanted to detect the level of MGMT promoter methylation in these cell lines and to investigate a potential association between MGMT promoter methylation and treatment resistance.

METHODS

Cells were treated with various concentrations of temozolomide and/or irradiated with 4 and 8 Gy. Radiosensitization by temozolomide was evaluated using proliferation assay and clonogenic assay, and MGMT DNA methylation was investigated using bisulfite next-generation sequencing.

RESULTS

In all tested canine cell lines, clonogenicity was inhibited significantly in combined treatment compared to radiation alone. All canine glial cell lines tested in this study were found to have high methylation levels of MGMT promoter.

CONCLUSIONS

Hence, an additive effect of combined treatment in MGMT negative canine glial tumour cell lines in vitro was detected. This motivates to further investigate the association between treatment resistance and MGMT, such as MGMT promoter methylation status.

Apigenin increases radiosensitivity of glioma stem cells by attenuating HIF-1α-mediated glycolysis

Apigenin, a natural flavonoid compound present in a variety of edible plants and health foods, has an anti-tumor effect and inhibits hypoxia inducible factor-lα (HIF-1α) expression in hypertrophic cardiac tissues. However, whether or not apigenin has a radiosensitization effect on glioma stem cells (GSCs) is unknown. Our present study aimed to investigate the effect of apigenin and its possible mechanisms. The human GSCs SU3 and its radioresistance line SU3-5R were treated with apigenin, radiation, or their combination, and the cell proliferation, migration, colony formation, and intracellular lactic acid and glycolytic related protein expressions were determined. Additionally, a cell model with hypoxia-induced HIF-1α expression was used and treated with apigenin. The current results displayed that the combination of apigenin and radiation could synergically reduce the viability, colony formation, and migration of the both GSCs. Moreover, this combination could also decrease the radiation-induced increments of glycolytic production lactic acid in the both GSCs and related protein expressions, including HIF-1α, glucose transporter (GLUT)-1/3, nuclear factor kappa B (NF-κB) p65, and pyruvate kinase isozyme type M2 (PKM2). Further study confirmed that after treatment of hypoxia-cultured SU3 or SU3-5R cells with apigenin, the expression levels of HIF-1α, GLUT-1/3, NF-κB p65, and PKM2 proteins were reduced. These results demonstrated that apigenin could increase the radiosensitivity of GSCs and its radiosensitization mechanisms were attributable to the attenuation of glycolysis, which might result from the inhibition of HIF-1α expression and subsequent reductions of GLUT-1/3, NF-κB, and PKM2 expressions.

Precision Radiotherapy for Gliomas: Implementing Novel Imaging Biomarkers to Improve Outcomes With Patient-Specific Therapy

ABSTRACT

Gliomas are the most common primary brain cancer, yet are extraordinarily challenging to treat because they can be aggressive and infiltrative, locally recurrent, and resistant to standard treatments. Furthermore, the treatments themselves, including radiation therapy, can affect patients' neurocognitive function and quality of life. Noninvasive imaging is the standard of care for primary brain tumors, including diagnosis, treatment planning, and monitoring for treatment response. This article explores the ways in which advanced imaging has and will continue to transform radiation treatment for patients with gliomas, with a focus on cognitive preservation and novel biomarkers, as well as precision radiotherapy and treatment adaptation. Advances in novel imaging techniques continue to push the field forward, to more precisely guided treatment planning, radiation dose escalation, measurement of therapeutic response, and understanding of radiation-associated injury.

Radiotherapy of High-Grade Gliomas: First Half of 2021 Update with Special Reference to Radiosensitization Studies

Albeit the effort to develop targeted therapies for patients with high-grade gliomas (WHO grades III and IV) is evidenced by hundreds of current clinical trials, radiation remains one of the few effective therapeutic options for them. This review article analyzes the updates on the topic "radiotherapy of high-grade gliomas" during the period 1 January 2021-30 June 2021. The high number of articles retrieved in PubMed using the search terms ("gliom* and radio*") and manually selected for relevance indicates the feverish research currently ongoing on the subject. During the last semester, significant advances were provided in both the preclinical and clinical settings concerning the diagnosis and prognosis of high-grade gliomas, their radioresistance, and the inevitable side effects of their treatment with radiation. The novel information concerning tumor radiosensitization was of special interest in terms of therapeutic perspective and was discussed in detail.

Therapeutic Potential of Berberine in the Treatment of Glioma: Insights into Its Regulatory Mechanisms

Glioma is known as one of the most common primary intracranial tumors accounting for four-fifths of malignant brain tumors. There are several biological pathways that play a synergistic, pathophysiological role in glioma, including apoptosis, autophagy, oxidative stress, and cell cycle arrest. According to previous rese arches, the drugs used in the treatment of glioma have been associated with significant limitations. Therefore, improved and/or new therapeutic platforms are required. In this regard, multiple flavonoids and alkaloids have been extensively studied in the treatment of glioma. Berberine is a protoberberine alkaloid with wide range of pharmacological activities, applicable to various pathological conditions. Few studies have reported beneficial roles of berberine in glioma. Berberine exerts its pharmacological functions in glioma by controlling different molecular and cellular pathways. We reviewed the existing knowledge supporting the use of berberine in the treatment of glioma and its effects on molecular and cellular mechanisms.

Effects of triptolide on radiosensitivity of human glioma cells and its mechanism

PURPOSE

To study the effect of triptolide (TP) on radiosensitivity of human glioma U251 cells and its mechanism, so as to provide new ideas and methods for the radiotherapy of glioma.

METHODS

U251 cells were treated with 10, 50, 100 nmol/L TP at different concentrations and irradiated with 0, 2, 4, 6, 8 Gy X-ray. The radiosensitivity of cells in each group were detected by MTT. U251 cells were then divided into control group, 10 nmol/L TP group, 4 Gy radiation group, 10 nmol/L TP + 4 Gy radiation group. The formation ability of U251 cells in each group was detected by colony formation assay. Flow cytometry was used to detect cell cycle and apoptosis in each group. Western blot was used to detect the changes of PI3K/Akt signal pathway in each group.

RESULTS

When 10, 50, 100 nmol/L TP were combined with 2, 4, 6, 8 Gy X-ray, the proliferation inhibition rate of U251 cells in each group increased significantly (p<0.05); compared with 10 nmol/L TP alone group and 4 Gy radiation alone group, the colony formation ability rate of U251 cells in 10 nmol/L TP + 4Gy radiation combined group decreased significantly (p<0.05), the cell cycle was blocked in G1 phase, and the apoptosis rate was significantly reduced (p<0.05). The level of p-pi3k and p-Akt decreased significantly (p<0.05).

CONCLUSION

Triptolide could significantly increase the radiosensitivity of human glioma U251 cells and play a role by inhibiting the PI3K/Akt signal pathway.

Adjuvant and concurrent temozolomide for 1p/19q non-co-deleted anaplastic glioma (CATNON; EORTC study 26053-22054): second interim analysis of a randomised, open-label, phase 3 study

BACKGROUND

The CATNON trial investigated the addition of concurrent, adjuvant, and both current and adjuvant temozolomide to radiotherapy in adults with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas. The benefit of concurrent temozolomide chemotherapy and relevance of mutations in the IDH1 and IDH2 genes remain unclear.

METHODS

This randomised, open-label, phase 3 study done in 137 institutions across Australia, Europe, and North America included patients aged 18 years or older with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas and a WHO performance status of 0-2. Patients were randomly assigned (1:1:1:1) centrally using a minimisation technique to radiotherapy alone (59·4 Gy in 33 fractions; three-dimensional conformal radiotherapy or intensity-modulated radiotherapy), radiotherapy with concurrent oral temozolomide (75 mg/m2 per day), radiotherapy with adjuvant oral temozolomide (12 4-week cycles of 150-200 mg/m2 temozolomide given on days 1-5), or radiotherapy with both concurrent and adjuvant temozolomide. Patients were stratified by institution, WHO performance status score, age, 1p loss of heterozygosity, the presence of oligodendroglial elements on microscopy, and MGMT promoter methylation status. The primary endpoint was overall survival adjusted by stratification factors at randomisation in the intention-to-treat population. A second interim analysis requested by the independent data monitoring committee was planned when two-thirds of total required events were observed to test superiority or futility of concurrent temozolomide. This study is registered with ClinicalTrials.gov, NCT00626990.

FINDINGS

Between Dec 4, 2007, and Sept 11, 2015, 751 patients were randomly assigned (189 to radiotherapy alone, 188 to radiotherapy with concurrent temozolomide, 186 to radiotherapy and adjuvant temozolomide, and 188 to radiotherapy with concurrent and adjuvant temozolomide). Median follow-up was 55·7 months (IQR 41·0-77·3). The second interim analysis declared futility of concurrent temozolomide (median overall survival was 66·9 months [95% CI 45·7-82·3] with concurrent temozolomide vs 60·4 months [45·7-71·5] without concurrent temozolomide; hazard ratio [HR] 0·97 [99·1% CI 0·73-1·28], p=0·76). By contrast, adjuvant temozolomide improved overall survival compared with no adjuvant temozolomide (median overall survival 82·3 months [95% CI 67·2-116·6] vs 46·9 months [37·9-56·9]; HR 0·64 [95% CI 0·52-0·79], p<0·0001). The most frequent grade 3 and 4 toxicities were haematological, occurring in no patients in the radiotherapy only group, 16 (9%) of 185 patients in the concurrent temozolomide group, and 55 (15%) of 368 patients in both groups with adjuvant temozolomide. No treatment-related deaths were reported.

INTERPRETATION

Adjuvant temozolomide chemotherapy, but not concurrent temozolomide chemotherapy, was associated with a survival benefit in patients with 1p/19q non-co-deleted anaplastic glioma. Clinical benefit was dependent on IDH1 and IDH2 mutational status.

FUNDING

Merck Sharpe & Dohme.

Model-based evaluation of image-guided fractionated whole-brain radiation therapy in pediatric diffuse intrinsic pontine glioma xenografts

Radiation therapy (RT) is currently the standard treatment for diffuse intrinsic pontine glioma (DIPG), the most common cause of death in children with brain cancer. A pharmacodynamic model was developed to describe the radiation-induced tumor shrinkage and overall survival in mice bearing DIPG. CD1-nude mice were implanted in the brain cortex with luciferase-labeled patient-derived orthotopic xenografts of DIPG (SJDIPGx7 H3F3AWT / K27 M and SJDIPGx37 H3F3AK27M / K27M ). Mice were treated with image-guided whole-brain RT at 1 or 2 Gy/fraction 5-days-on 2-days-off for a cumulative dose of 20 or 54 Gy. Tumor progression was monitored with bioluminescent imaging (BLI). A mathematical model describing BLI and overall survival was developed with data from mice receiving 2 Gy/fraction and validated using data from mice receiving 1 Gy/fraction. BLI data were adequately fitted with a logistic tumor growth function and a signal distribution model with linear radiation-induced killing effect. A higher tumor growth rate in SJDIPGx37 versus SJDIPGx7 xenografts and a killing effect decreasing with higher tumor baseline (p < 0.0001) were identified. Cumulative radiation dose was suggested to inhibit the tumor growth rate according to a Hill function. Survival distribution was best described with a Weibull hazard function in which the hazard baseline was a continuous function of tumor BLI. Significant differences were further identified between DIPG cell lines and untreated versus treated mice. The model was adequately validated with mice receiving 1 Gy/fraction and will be useful in guiding future preclinical trials incorporating radiation and to support systemic combination therapies with RT.

γ-Glutamyl transpeptidase-activatable near-infrared nanoassembly for tumor fluorescence imaging-guided photothermal therapy

Rationale: Precise treatment of tumors is attracting increasing attention. Molecular probes simultaneously demonstrating the diagnostic signal and pharmacological effect in response to tumor microenvironment are highly desired. γ-glutamyl transpeptidase (GGT) is a biomarker with significantly up-regulated expression in the tumor area. We developed a GGT responsive near-infrared (NIR) nanoassembly for tumor-specific fluorescence imaging-guided photothermal therapy. Methods: The GGT responsive NIR probe was constructed by conjugating GGT-specific substrate γ-glutamic acid (γ-Glu) with cyanine fluorophore (NRh-NH2) via amide reaction. The resulting NRh-G spontaneously assembled into nanoparticles (NRh-G-NPs) around 50 nm. The NPs were characterized and the properties evaluated in the presence or absence of GGT. Subsequently, we studied fluorescence imaging and photothermal therapy of NRh-G-NPs in vitro and in vivo. Results: NRh-G-NPs, upon specific reaction with GGT, turned into NRh-NH2-NPs, showing a ~180-fold fluorescence enhancement and excellent photothermal effect recovery. NRh-G-NPs could selectively light up U87MG tumor cells while their fluorescence was weak in L02 human normal liver cells. The NPs also showed excellent tumor cell ablation upon laser irradiation. After intravenous injection into tumor-bearing mice, NRh-G-NPs could arrive in the tumor area and specifically light up the tumor. Following laser irradiation, the tumor could be completely erased with no tumor reoccurrence for up to 40 days. Conclusions: NRh-G-NPs were specifically responsive to GGT overexpressed in U87MG tumor cells and selectively lit up the tumor for imaging-guided therapy. Besides, the recovery of photothermal property in the tumor area could improve cancer therapy precision and decreased side effects in normal tissues.

Temozolomide chemotherapy combined with radiotherapy versus radiotherapy alone after surgery in patients with high-risk low-grade gliomas

PURPOSE

The purpose of this study was to compare the clinical efficacy and safety of temozolomide (TMZ) combined with three-dimensional conformal radiotherapy (3D-CRT) and radiotherapy alone after surgery in patients with high-risk low-grade gliomas (LGGs).

METHODS

Patients (N=110) with LGGs were enrolled. Patients receiving TMZ chemotherapy combined with radiotherapy were considered as combination group (n=55), while those treated with radiotherapy alone were regarded as control group (n=55). The patients were followed up, and the overall survival (OS) and progression-free survival (PFS) were recorded. Finally, factors possibly affecting prognosis were analyzed.

RESULTS

The follow-up results exhibited median OS [(67.4±8.8) months vs. (63.9±8.6) months] and median PFS [(51.1±7.6) months vs. (46.8±6.9) months] as well as three-year OS rate and three-year PFS rate in combination group and control group. Log-rank test indicated that the difference in OS was not statistically significant between the two groups of patients, and PFS in combination group was significantly superior to that in control group. The results of univariate and multivariate analysis displayed that age <40 years old and complete tumor resection were independent factors affecting the three-year OS of patients with high-risk LGGs. Besides, age <40 years old, complete tumor resection and TMZ chemotherapy combined with radiotherapy after surgery were independent factors affecting the three-year PFS of patients with high-risk LGGs.

CONCLUSION

TMZ chemotherapy combined with radiotherapy after surgery in patients with high-risk LGGs can prominently improve clinical efficacy, prolong PFS, and facilitate tolerance to adverse reactions, but not prolong the OS of patients. The OS is notably prolonged in patients aged <40 years old and receiving complete tumor resection.

Proton re-irradiation of unresectable recurrent brain gliomas: clinical outcomes and toxicity

PURPOSE

To assess the efficacy and tolerance of proton re-irradiation in patients with unresectable recurrence of previously irradiated brain gliomas.

METHODS

Between February 2016 and December 2019, 44 patients with in-field recurrence after prior irradiation of brain gliomas were irradiated with intensity-modulated proton therapy. Seven patients (15.9%) originally had low-grade (WHO grade I-II) gliomas, nine patients (20.4%) had anaplastic astrocytoma (WHO grade III), and 28 patients (63.7%) had glioblastoma (WHO grade IV). All tumors were unresectable due to their localization. After a median time from the prior irradiation of 28.0 months [range, 12 to 173], patients received PT with 2.0 and 3.0 GyRBE per fraction, with median proton EQD2 (/=10) to a tumor of 55.0 GyRBE [range, 46.0 to 61.75]. Adjuvant chemotherapy (Temozolomide, or Procarbazine, Lomustine and vincristine, or Bevacizumab with Irinotecan) received 86.9% of the patients (n=40). Treatment-related toxicity was reported following CTCAE.

RESULTS

The median survival time was 12 months, with 1-year and 2-years overall survival (OS) amounting to 49.6% and 35.1%, respectively. The median progression-free survival (PFS) was 9 months, with 1- and 2-years PFS of 30.5% and 10.2%, respectively. Twenty-six patients died by the time of analysis; among them were 5 non-cancer deaths (19.2%), and 4 patients (15.4%) died of chemotherapy-associated severe toxicity. The incidence rate of radiation-induced necrosis was 6.8% (3 events).

CONCLUSIONS

Based on our results, we suggest re-irradiation of recurrent brain gliomas with proton therapy is able to achieve reasonable tumor control. Low adverse events rate and promising outcomes make it a safe treatment option with curative intent, even in unresectable cases.

Feasibility and Therapeutic Potential of Peptide Receptor Radionuclide Therapy for High-Grade Gliomas

PURPOSE

This pilot study tested the principle that 177Lu-DOTATATE may be applied to patients with high-grade gliomas (HGGs) that are either inoperable or refractory to the standard conventional treatments and also assessed whether this approach could be a viable therapeutic plan in this dilemma.

METHODS

In this prospective study, 16 subjects experiencing HGGs that were either inoperable or refractory to the standard conventional treatments were included. All the patients checked for somatostatin receptor expression on the tumors. The patients were treated with 1 to 4 cycles of IV 177Lu-DOTATATE. The primary end point was radiological response after peptide receptor radionuclide therapy, and the secondary end point was improved quality of life using Karnofsky Performance Score and Eastern Cooperative Oncology Group score.

RESULTS

In total, 16 subjects (10 males and 6 females) with a mean age of 55.68 ± 13.17 years (26-73 years) participated in the study. Of them, 8 patients were new HGG cases, and 8 patients had recurrent tumors. The participants' responses to treatments were complete remission in 12.5% of (n = 2), partial remission in 31.25% (n = 5), disease stability in 18.7% (n = 3), and disease progression in 37.5% (n = 6). In total, pretreatment and posttreatment Karnofsky Performance Score and Eastern Cooperative Oncology Group scores did not improved (P > 0.05). The patients were followed up from 1 month to 26 months (median, 3 months).

CONCLUSIONS

This preliminary result suggests that peptide receptor radionuclide therapy using 177Lu-DOTATATE may be associated with positive effects in patients with HGGs (grade III-IV). However, this approach should be evaluated in a more homogeneous group of patients with more favorable performance status.

Oncolytic HSV-1 G207 Immunovirotherapy for Pediatric High-Grade Gliomas

BACKGROUND

Outcomes in children and adolescents with recurrent or progressive high-grade glioma are poor, with a historical median overall survival of 5.6 months. Pediatric high-grade gliomas are largely immunologically silent or "cold," with few tumor-infiltrating lymphocytes. Preclinically, pediatric brain tumors are highly sensitive to oncolytic virotherapy with genetically engineered herpes simplex virus type 1 (HSV-1) G207, which lacks genes essential for replication in normal brain tissue.

METHODS

We conducted a phase 1 trial of G207, which used a 3+3 design with four dose cohorts of children and adolescents with biopsy-confirmed recurrent or progressive supratentorial brain tumors. Patients underwent stereotactic placement of up to four intratumoral catheters. The following day, they received G207 (10⁷ or 10⁸ plaque-forming units) by controlled-rate infusion over a period of 6 hours. Cohorts 3 and 4 received radiation (5 Gy) to the gross tumor volume within 24 hours after G207 administration. Viral shedding from saliva, conjunctiva, and blood was assessed by culture and polymerase-chain-reaction assay. Matched pre- and post-treatment tissue samples were examined for tumor-infiltrating lymphocytes by immunohistologic analysis.

RESULTS

Twelve patients 7 to 18 years of age with high-grade glioma received G207. No dose-limiting toxic effects or serious adverse events were attributed to G207 by the investigators. Twenty grade 1 adverse events were possibly related to G207. No virus shedding was detected. Radiographic, neuropathological, or clinical responses were seen in 11 patients. The median overall survival was 12.2 months (95% confidence interval, 8.0 to 16.4); as of June 5, 2020, a total of 4 of 11 patients were still alive 18 months after G207 treatment. G207 markedly increased the number of tumor-infiltrating lymphocytes.

CONCLUSIONS

Intratumoral G207 alone and with radiation had an acceptable adverse-event profile with evidence of responses in patients with recurrent or progressive pediatric high-grade glioma. G207 converted immunologically "cold" tumors to "hot." (Supported by the Food and Drug Administration and others; ClinicalTrials.gov number, NCT02457845.).

Increasing the accumulation of aptamer AS1411 and verapamil conjugated silver nanoparticles in tumor cells to enhance the radiosensitivity of glioma

Radioresistance significantly decreases the efficacy of radiotherapy, which can ultimately lead to tumor recurrence and metastasis. As a novel type of nano-radiosensitizer, silver nanoparticles (AgNPs) have shown promising radiosensitizing properties in the radiotherapy of glioma, but their ability to efficiently enter and accumulate in tumor cells needs to be improved. In the current study, AS1411 and verapamil (VRP) conjugated bovine serum albumin (BSA) coated AgNPs (AgNPs@BSA-AS-VRP) were synthesized and characterized. Dark-field imaging and inductively coupled plasma mass spectrometry were applied to investigate the accumulation of AgNPs@BSA-AS and AgNPs@BSA-AS-VRP mixed in different ratios in U251 glioma cells. To assess the influences of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP on the P-glycoprotein (P-gp) efflux activity, rhodamine 123 accumulation assay was carried out. Colony formation assay and tumor-bearing nude mice model were employed to examine the radiosensitizing potential of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP. Thioredoxin Reductase (TrxR) Assay Kit was used to detect the TrxR activity in cells treated with different functionally modified AgNPs. Characterization results revealed that AgNPs@BSA-AS-VRP were successfully constructed. When AgNPs@BSA-AS and AgNPs@BSA-AS-VRP were mixed in a ratio of 19:1, the amount of intracellular nanoparticles increased greatly through AS1411-mediated active targeting and inhibition of P-gp activity. In vitro and in vivo experiments clearly showed that the radiosensitization efficacy of 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP was much stronger than that of AgNPs@BSA and AgNPs@BSA-AS. It was also found that 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP significantly inhibited intracellular TrxR activity. These results indicate that 19:1 mixed AgNPs@BSA-AS and AgNPs@BSA-AS-VRP can effectively accumulate in tumor cells and have great potential as high-efficiency nano-radiosensitizers in the radiotherapy of glioma.

Clinical experience of convection-enhanced delivery (CED) of carboplatin and sodium valproate into the pons for the treatment of diffuse intrinsic pontine glioma (DIPG) in children and young adults after radiotherapy

PURPOSE

Effective treatment of diffuse intrinsic pontine glioma (DIPG) remains a formidable challenge due to inadequate penetration of the blood-brain barrier (BBB) by systemically administered chemotherapies. The BBB can be overcome by directly infusing drugs into pons using method of convection-enhanced delivery (CED). We describe our clinical experience and what we have learned about the safety and feasibility of treating DIPG with intermittent CED of carboplatin and sodium valproate to the pons through the Renishaw Drug Delivery System (RDDS).

METHODS

Retrospective review (2017-2020) of children with DIPG, who following radiotherapy, received compassionate treatment commencing 3.3-10 months post-diagnosis (median 4.9 months). They received up to 7 cycles of 3-6 weekly pontine infusions of carboplatin (0.12-0.18 mg/ml) and sodium valproate (14.4-28.8 mg/ml).

RESULTS

13 children 3-19 years (mean 6.9 years) were treated. There were no surgical complications. With the exception of infusion channels blocking in one device, there were no adverse device effects. Two patients developed persistent 6th nerve palsies, which led to drug concentration reduction in the combination therapy. Subsequently infusion/ drug-related toxicities were transient. Tumour was controlled in pons in 10/13 patients. Median progression-free survival (PFS) was 13.0 months, while median overall survival (OS) was 15.3 months.

CONCLUSIONS

Use of the RDDS was safe and well tolerated in all 13 patients. Treatment improved control of pontine disease resulting in longer PFS and OS and merits further evaluation in a clinical trial.

The Prognostic Impact of Radiotherapy in Conjunction with Temozolomide in Diffuse Intrinsic Pontine Glioma: A Systematic Review and Meta-Analysis

OBJECTIVE

Diffuse intrinsic pontine glioma (DIPG) is a rare and devastating brainstem glioma that occurs predominately in children. To date, the prognostic impact of radiotherapy (RT) in conjunction with temozolomide (TMZ) in DIPG has not been thoroughly analyzed. The aim of this meta-analysis was to analyze the effectiveness of RT quantitatively and precisely in conjunction with TMZ in improving the prognosis of DIPG.

METHODS

A systematic search of 8 electronic databases was conducted. Articles mainly discussing the prognostic impact of RT in conjunction with TMZ in DIPG were selected. The pooled 1- and 2-year overall survival (OS) and progression-free survival (PFS) were calculated.

RESULTS

A total of 14 studies fulfilled our inclusion criteria, involving 283 cases of patients with DIPG who were treated with RT in conjunction with TMZ. The pooled 1- and 2-year OS of this treatment was 43% and 11%, respectively. The pooled 1- and 2-year PFS was 20% and 2%, respectively. Subgroup analysis revealed that the heterogeneity remained almost the same in all stratum. Egger's test demonstrated that the possibility of publication bias was low.

CONCLUSIONS

Requirements of up-to-date evidence on evaluating the prognostic impact of this therapy are urgent.

Tumor genotype dictates radiosensitization after Atm deletion in primary brainstem glioma models

Diffuse intrinsic pontine glioma (DIPG) kills more children than any other type of brain tumor. Despite clinical trials testing many chemotherapeutic agents, palliative radiotherapy remains the standard treatment. Here, we utilized Cre/loxP technology to show that deleting Ataxia telangiectasia mutated (Atm) in primary mouse models of DIPG can enhance tumor radiosensitivity. Genetic deletion of Atm improved survival of mice with p53-deficient but not p53 wild-type gliomas after radiotherapy. Similar to patients with DIPG, mice with p53 wild-type tumors had improved survival after radiotherapy independent of Atm deletion. Primary p53 wild-type tumor cell lines induced proapoptotic genes after radiation and repressed the NRF2 target, NAD(P)H quinone dehydrogenase 1 (Nqo1). Tumors lacking p53 and Ink4a/Arf expressed the highest level of Nqo1 and were most resistant to radiation, but deletion of Atm enhanced the radiation response. These results suggest that tumor genotype may determine whether inhibition of ATM during radiotherapy will be an effective clinical approach to treat DIPGs.

Knockdown of circ_0008344 contributes to radiosensitization in glioma via miR-433-3p/RNF2 axis

Numerous studies have identified that circular RNAs (circRNAs) functioned as important regulators in tumor initiation, carcinogenesis, drug or radiation resistance. This study aims to reveal the function of circ_0008344 on radiosensitivity in glioma. The quantitative real-time polymerase chain reaction (qRT-PCR) was implemented for detecting the circ_0008344 and microRNA-433-3p (miR-433-3p) levels. Cell survival intensity and apoptosis were analyzed through colony formation assay and flow cytometry respectively. The protein levels were examined via Western blot. Dual-luciferase reporter assay was exploited for the analysis of target combination. Xenograft models were established in mice for circ_0008344 research in vivo. Our data showed that circ_0008344 level was signally increased in radioresistant glioma tissues and its down-regulation facilitated the susceptibility of glioma cells to radiation. Additionally, we found that circ_0008344 could interact with miR-433-3p and regulated radiosensitivity of glioma cells via sponging miR-433-3p. Ring finger protein 2 (RNF2) was proved to be a target of miR-433-3p and it was regulated by circ_0008344/miR-433-3p axis. The promotion of circ_0008344 knockdown on radiosensitivity was counteracted by RNF2 overexpression in glioma cells. Further experiment in vivo indicated that circ_0008344 down-regulation inhibited glioma growth and acted on miR-433-3p/RNF2 axis to enhance the radiosensitivity in glioma. These evidences manifested that knockdown of circ_0008344 exerted the radiosensitivity-promoting effect on glioma via the miR-433-3p-mediated RNF2 down-regulation, identifying circ_0008344 as a novel diagnostic biomarker of radioresistance and therapeutic target in glioma radiotherapy.

NAD+ depletion radiosensitizes 2-DG-treated glioma cells by abolishing metabolic adaptation

Two-deoxy-d-glucose (2-DG) mediated glucose restriction (GR) has been applied as a potential therapeutic strategy for tumor clinical treatments. However, increasing evidences have indicated that 2-DG alone is inefficient in killing tumor cells, and the effect of 2-DG on modifying tumor radio-responses also remains controversial. In this study, we found that 2-DG triggered metabolic adaption in U87 glioma cells by up-regulating nicotinamide phosphoribosyltransferase (NAMPT) and cellular NAD+ content, which abolished 2-DG-induced potential radiosensitizing effect in glioma cells. Strikingly, NAD+ depletion evoked notable oxidative stress by NADPH reduction and hence re-radiosensitized 2-DG-treated glioma cells. Furthermore, isocitrate dehydrogenase-1 (IDH1) mutant U87 glioma cells with deficiency in the rate-limiting enzyme of Preiss-Handler pathway nicotinate phosphoribosyltransferase (Naprt1) revealed notable 2-DG-induced oxidative stress and radiosensitization. Our findings implied that targeting NAD+ could radiosensitize gliomas with GR, and 2-DG administration could be benefit for tumor patients with IDH1 mutation.

Therapeutic effect of thalidomide combined with temozolomide and three-dimensional conformal radiotherapy for patients with high-grade gliomas after operation

PURPOSE

To explore the efficacy and safety of 125 I radioactive seed implantation combined with intermittent hormonal therapy (IHT) in the clinical treatment of moderate- and high-risk non-metastatic prostate cancer.

METHODS

A total of 136 patients were divided into the observation group (n=68) and the control group (n=68). In the observation group, 125I radioactive seed implantation was performed, bicalutamide capsules were taken orally immediately after operation, and leuprorelin was injected from 1 week after operation. In the control group, IHT alone was administered. The level of serum prostate specific antigen (PSA), maximum urine flow rate (Q max ) and international prostate symptom scale (IPSS) score were compared between the two groups before and after treatment. Moreover, the overall survival (OS), tumor-specific survival (TSS), distant metastasis-free survival (DMFS) and progression-free survival (PFS) of patients were recorded.

RESULTS

There were no statistically significant differences in the PSA level, Q max and IPSS score between the two groups before treatment (p>0.05). At 6, 12 and 24 months after treatment, the level of PSA in the observation group was significantly lower than in the control group (p=0.005, p<0.001, p<0.001). At 24 months after treatment, Q max in the observation group was significantly higher than in the control group (p=0.025). At 12 and 24 months after treatment, the IPSS score in the observation group was significantly lower than that in the control group (p=0.013, p=0.002). During the follow-up period, the intermission time of hormonal therapy and PFS time in the observation group were obviously longer than those in control group (p<0.001). In the two groups, OS was 97.1% and 94.1%, TSS was 95.6% and 92.6%, DMFS was 82.4% and 66.2%, and PFS was 72.1% and 51.5%, respectively. It can be seen that OS and TSS had no statistically significant differences between the two groups (p=0.405, p=0.496), while DMFS and PFS in the observation group were remarkably superior to those in the control group (p=0.037, p=0.022).

CONCLUSIONS

125 I seed implantation combined with IHT is safe and effective in the clinical treatment of patients with moderate- and high-risk non-metastatic prostate cancer. Compared with the IHT alone, the combination therapy can significantly prolong the intermission time of hormonal therapy and effectively control the progression of disease.

Evaluation of perfusion MRI value for tumor progression assessment after glioma radiotherapy: A systematic review and meta-analysis

OBJECTIVES

This study aimed to evaluate the diagnostic performance of magnetic resonance perfusion-weighted imaging (PWI) as a noninvasive method to assess post-treatment radiation effect and tumor progression in patients with glioma.

METHODS

A systematic literature search was performed in the PubMed, Cochrane Library, and Embase databases up to March 2020. The quality of the included studies was assessed by the quality assessment of diagnostic accuracy studies 2. Data were extracted to calculate sensitivity, specificity, and diagnostic odds ratio (DOR), 95% Confidence interval (CI) and analyze the heterogeneity of the studies (Spearman correlation coefficient, I2 test). We performed meta-regression and subgroup analyses to identify the impact of study heterogeneity.

RESULTS

Twenty studies were included, with available data for analysis on 939 patients and 968 lesions. All included studies used dynamic susceptibility contrast (DSC) PWI, four also used dynamic contrast-enhanced PWI, and three also used arterial spin marker imaging PWI. When DSC was considered, the pooled sensitivity and specificity were 0.83 (95% CI, 0.79 to 0.86) and 0.83 (95% CI, 0.78 to 0.87), respectively; pooled DOR, 21.31 (95% CI, 13.07 to 34.73); area under the curve (AUC), 0.887; Q∗, 0.8176. In studies using dynamic contrast-enhanced, the pooled sensitivity and specificity were 0.73 (95% CI, 0.66 to 0.80) and 0.80 (95% CI, 0.69 to 0.88), respectively; pooled DOR, 10.83 (95% CI, 2.01 to 58.43); AUC, 0.9416; Q∗, 0.8795. In studies using arterial spin labeling, the pooled sensitivity and specificity were 0.79 (95% CI, 0.69 to 0.87) and 0.78 (95% CI, 0.67 to 0.87), respectively; pooled DOR, 15.63 (95% CI, 4.61 to 53.02); AUC, 0.8786; Q∗, 0.809.

CONCLUSIONS

Perfusion magnetic resonance imaging displays moderate overall accuracy in identifying post-treatment radiation effect and tumor progression in patients with glioma. Based on the current evidence, DSC-PWI is a relatively reliable option for assessing tumor progression after glioma radiotherapy.

Long-term outcome of stereotactic brachytherapy with temporary Iodine-125 seeds in patients with WHO grade II gliomas

BACKGROUND

This long-term retrospective analysis aimed to investigate the outcome and toxicity profile of stereotactic brachytherapy (SBT) in selected low-grade gliomas WHO grade II (LGGII) in a large patient series.

METHODS

This analysis comprised 106 consecutive patients who received SBT with temporary Iodine-125 seeds for histologically verified LGGII at the University of Munich between March 1997 and July 2011. Investigation included clinical characteristics, technical aspects of SBT, the application of other treatments, outcome analyses including malignization rates, and prognostic factors with special focus on molecular biomarkers.

RESULTS

For the entire study population, the 5- and 10-years overall survival (OS) rates were 79% and 62%, respectively, with a median follow-up of 115.9 months. No prognostic factors could be identified. Interstitial radiotherapy was applied in 51 cases as first-line treatment with a median number of two seeds (range 1-5), and a median total implanted activity of 21.8 mCi (range 4.2-43.4). The reference dose average was 54.0 Gy. Five- and ten-years OS and progression-free survival rates after SBT were 72% and 43%, and 40% and 23%, respectively, with a median follow-up of 86.7 months. The procedure-related mortality rate was zero, although an overall complication rate of 16% was registered. Patients with complications had a significantly larger tumor volume (p = 0.029).

CONCLUSION

SBT is a minimally invasive treatment modality with a favorable outcome and toxicity profile. It is both an alternative primary treatment method as well as an adjunct to open tumor resection in selected low-grade gliomas.

Therapeutic effect of thalidomide combined with temozolomide and three-dimensional conformal radiotherapy for patients with high-grade gliomas after operation

PURPOSE

Purpose: To investigate the clinical therapeutic effect and safety of thalidomide combined with temozolomide (TMZ) and three-dimensional conformal radiotherapy for patients with high-grade gliomas after operation.

METHODS

Methods: The clinical data of 108 patients with high-grade gliomas undergoing operation in our hospital from September 2014 to December 2016 were retrospectively analyzed, of which 54 received thalidomide combined with TMZ and three-dimensional conformal radiotherapy (thalidomide group) and 54 received TMZ combined with three-dimensional conformal radiotherapy (control group). The clinical data of all patients were collected, and the short-term therapeutic effect, adverse reactions after treatment and quality of life scores were compared between the two groups of patients. Thereafter, the level of serum immune factors of the patients was recorded, and the overall survival (OS) rate and progression-free survival (PFS) rate of the patients were followed up and recorded.

RESULTS

Results: The therapeutic effect was evaluated in all the patients at 1 month after treatment. It was found that the overall response rate (ORR) in thalidomide group [68.5% (37/54)] was markedly higher than that in control group [44.4% (24/54)] (p=0.012), but the difference in the disease control rate (DCR) between thalidomide group [92.6% (50/54)] and control group [83.3% (45/54)] was not statistically significant (p=0.139). After treatment, the scores of 36-Item Short Form Health Survey (SF-36) evaluating the quality of life in thalidomide group were higher than that in control group, in which the physical function score was statistically significantly different between the two groups (p=0.028), whereas the scores of the other items did not statistically significantly differ between the two groups (p>0.05). Following treatment, the levels of serum hepatocyte growth factor (HGF), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-17, vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) were remarkably reduced in the two groups of patients, and these indexes in thalidomide group were lower than those in control group after treatment. Among them, HGF (p=0.069), TNF-α (p=0.076), IL-6 (p=0.149) and IL-17 (p=0.114) showed no statistically significant differences, but VEGF and EGF were statistically significantly different between the two groups (p<0.001). Moreover, adverse reactions were mainly manifested as myelosuppression, nausea and vomiting, constipation, liver function injury, drowsiness and neurotoxicity (grade I-II in most cases), which returned to normal after symptomatic treatment. Besides, the incidence rate of drowsiness of the patients in thalidomide group was notably lower than that in control group (p=0.029), but the difference in the incidence rate of other manifestations was not statistically significant (p>0.05). Additionally, the follow-up results manifested that the median OS was (16.1±3.6) months, (12.8±3.9) months, respectively, and the median PFS was (9.0±3.2) months and (12.3±3.4) months, respectively, in thalidomide group and control group. Furthermore, log-rank test revealed that the patients in thalidomide group had longer OS (p=0.025) and PFS (p=0.040) than those in control group.

CONCLUSIONS

Conclusions: The application of thalidomide combined with TMZ and three-dimensional conformal radiotherapy for high-grade glioma patients after operation can prominently enhance the clinical therapeutic effect, improve patient quality of life, prolong survival, and produce tolerable adverse reactions.

The Change of Soluble Programmed Cell Death-Ligand 1 in Glioma Patients Receiving Radiotherapy and Its Impact on Clinical Outcomes

Background

The programmed cell death ligand 1 (PD-L1) plays a key role in glioma development. However, due to the specificity of glioma's anatomical position, the role of its expression as a tumor biomarker is limited. It has been proven that the levels of soluble programmed death-ligand 1 (sPD-L1) are associated with prognosis in many malignancies including glioma. However, the expression of sPD-L1 in glioma patients receiving radiotherapy (RT) remains unclear. The purpose of this study was to evaluate the concentration of sPD-L1 in the plasma of glioma patients before and after RT and to explore its relationship with clinical outcomes.

Methods

Between October 2017 and September 2018, glioma patients treated with RT (30 ± 10 Gy, 2 Gy/f) were enrolled, and blood samples were collected before and after RT. We quantified the sPD-L1 levels by enzyme-linked immunosorbent assay (ELISA). The isocitrate dehydrogenase-1 (IDH-1) mutational status and Ki-67 expression of tumors were evaluated by immunohistochemistry. Glioma murine model were used to address whether circulating sPD-L1 molecules are directly targeted by an anti-PD-L1 antibody. The associations between sPD-L1 and clinical features were assessed with Pearson's or Spearman's correlation analysis. The progression-free survival (PFS) and overall survival (OS) were determined by the Kaplan-Meier method.

Results

Sixty glioma patients were included, with a median age of 52 years. The proportions of grade I, II, III, and IV gliomas were 6.7%, 23.3%, 28.4%, and 41.6%, respectively. The baseline sPD-L1 levels were significantly associated with tumor grade, IDH-1 mutation status and Ki-67 expression. Using 14.35 pg/ml as the cutoff, significantly worse PFS and OS were both observed in patients with higher baseline levels of sPD-L1 (P = 0.027 and 0.008, respectively). RT significantly increased the mean level of sPD-L1 (P < 0.001). Further analysis showed that the level of sPD-L1 in IDH-1 mutation patients was higher than that in wild-type patients. Furthermore, an analysis of glioma murine model indicated that anti-PD-L1 antibody combine with RT can be a potentially powerful cancer therapy.

Conclusion

This study reported that sPD-L1 might be a potential biomarker to predict the outcome in glioma patients receiving RT. The elevated level of sPD-L1 after RT suggested that the strategy of a combination of immune checkpoint inhibitors and RT might be promising for glioma patients, especially for those with IDH-1 mutations.