Receptor tyrosine kinase (RTK) targeting in pediatric high-grade glioma and diffuse midline glioma: Pre-clinical models and precision medicine

Radiotherapy plus temozolomide with or without anlotinib in H3K27M-mutant diffuse midline glioma: A retrospective cohort study

BACKGROUND

Besides the hallmark of H3K27M mutation, aberrant amplifications of receptor tyrosine kinases (RTKs) are commonly observed in diffuse midline glioma (DMG), a highly malignant brain tumor with dismal prognosis. Here, we intended to evaluate the efficacy and safety of a multitarget RTK inhibitor anlotinib in patients with H3K27M-DMG.

METHODS

A total of 40 newly diagnosed H3K27M-DMG patients including 15 with anlotinib and 25 without anlotinib treatment were retrospectively enrolled in this cohort. Progression-free survival (PFS), overall survival (OS), and toxicities were assessed and compared.

RESULTS

The median PFS and OS of all patients in this cohort were 8.5 months (95% CI, 6.5-11.3) and 15.5 months (95% CI, 12.6-17.1), respectively. According to the Response Assessment in Neuro-Oncology (RANO) criteria, the disease control rate in the anlotinib group [93.3%, 95% confidence interval (CI), 70.2-98.8] was significantly higher than those without anlotinib (64%, 95% CI: 40.5-79.8, p = 0.039). The median PFS of patients with and without anlotinib was 11.6 months (95% CI, 7.8-14.3) and 6.4 months (95% CI, 4.3-10.3), respectively. Both the median PFS and OS of DMG patients treated with anlotinib were longer than those without anlotinib in the infratentorial patients (PFS: 10.3 vs. 5.4 months, p = 0.006; OS: 16.6 vs. 8.7 months, p = 0.016). Multivariate analysis also indicated anlotinib (HR: 0.243, 95% CI: 0.066-0.896, p = 0.034) was an independent prognosticator for longer OS in the infratentorial subgroup. In addition, the adverse events of anlotinib administration were tolerable in the whole cohort.

CONCLUSIONS

This study first reported that anlotinib combined with Stupp regimen is a safe and feasible regimen for newly diagnosed patients with H3K27M-DMG. Further, anlotinib showed significant efficacy for H3K27M-DMG located in the infratentorial region.

Elucidation and Pharmacologic Targeting of Master Regulator Dependencies in Coexisting Diffuse Midline Glioma Subpopulations

Diffuse Midline Gliomas (DMGs) are universally fatal, primarily pediatric malignancies affecting the midline structures of the central nervous system. Despite decades of clinical trials, treatment remains limited to palliative radiation therapy. A major challenge is the coexistence of molecularly distinct malignant cell states with potentially orthogonal drug sensitivities. To address this challenge, we leveraged established network-based methodologies to elucidate Master Regulator (MR) proteins representing mechanistic, non-oncogene dependencies of seven coexisting subpopulations identified by single-cell analysis-whose enrichment in essential genes was validated by pooled CRISPR/Cas9 screens. Perturbational profiles of 372 clinically relevant drugs helped identify those able to invert the activity of subpopulation-specific MRs for follow-up in vivo validation. While individual drugs predicted to target individual subpopulations-including avapritinib, larotrectinib, and ruxolitinib-produced only modest tumor growth reduction in orthotopic models, systemic co-administration induced significant survival extension, making this approach a valuable contribution to the rational design of combination therapy.

Feasibility and antitumour activity of the FGFR inhibitor erdafitnib in three paediatric CNS tumour patients

Alterations of the fibroblast growth factor (FGF) signalling pathway are increasingly recognized as frequent oncogenic drivers of paediatric brain tumours. We report on three patients treated with the selective FGFR1-4 inhibitor erdafitinib. Two patients were diagnosed with a posterior fossa ependymoma group A (PFA EPN) and one with a low-grade glioma (LGG), harbouring FGFR3/FGFR1 overexpression and an FGFR1 internal tandem duplication (ITD), respectively. While both EPN patients did not respond to erdafitinib treatment, the FGFR1-ITD-harbouring tumour showed a significant decrease in tumour volume and contrast enhancement throughout treatment. The tumour remained stable 6 months after treatment discontinuation.

Clinicopathological analysis of BRAF and non-BRAF MAPK pathway-altered gliomas in paediatric and adult patients: a single-institution study of 40 patients

AIMS

Mitogen-activated protein kinase (MAPK) pathway alteration is a major oncogenic driver in paediatric low-grade gliomas (LGG) and some adult gliomas, encompassing BRAF (most common) and non-BRAF alterations. The aim was to determine the frequency, molecular spectrum and clinicopathological features of MAPK-altered gliomas in paediatric and adult patients at our neuropathology site in Kuwait.

METHODS

We retrospectively searched the data of molecularly sequenced gliomas between 2018 and 2023 for MAPK alterations, revised the pathology in view of the 2021 WHO classification and evaluated the clinicopathological data for possible correlations.

RESULTS

Of 272 gliomas, 40 (15%) harboured a MAPK pathway alteration in 19 paediatric (median 9.6 years; 1.2-17.6) and 21 adult patients (median 37 years; 18.9-89.2), comprising 42% and 9% of paediatric and adult cases, respectively. Pilocytic astrocytoma and glioblastoma were the most frequent diagnoses in children (47%) and adults (43%), respectively. BRAF V600E (n=17, 43%) showed a wide distribution across age groups, locations and pathological diagnoses while KIAA1549::BRAF fusion (n=8, 20%) was spatially and histologically restricted to cerebellar paediatric LGGs. Non-V600E variants and BRAF amplifications accompanied other molecular aberrations in high-grade tumours. Non-BRAF MAPK alterations (n=8) included mutations and gene fusions involving FGFR1, NTRK2, NF1, ROS1 and MYB. Fusions included KANK1::NTRK2, GOPC::ROS1 (both infant hemispheric gliomas), FGFR1::TACC1 (diffuse LGG), MYB::QKI (angiocentric glioma) and BCR::NTRK2 (glioblastoma). Paradoxical H3 K27M/MAPK co-mutations were observed in two LGGs.

CONCLUSION

The study provided insights into MAPK-altered gliomas in Kuwait highlighting the differences among paediatric and adult patients and providing a framework for planning therapeutic polices.

The Spectrum of Molecular Pathways in Gliomas-An Up-to-Date Review

During the last 20 years, molecular alterations have gained increasing significance in the diagnosis and biological assessment of tumors. Gliomas represent the largest group of tumors of the central nervous system, and the main aim of this review is to present the current knowledge on molecular pathways and their alterations in gliomas. A wide range of new insights has been gained, including evidence for the involvement of the WNT pathway or the hippo pathway in the pathobiology of gliomas, indicating a broad involvement of different pathways formerly not considered to play a central role in gliomas. Even new aspects of angiogenic, apoptotic, and metabolic pathways are presented, as well as the rapidly growing field of epigenetic processes, including non-coding RNAs. The two major conclusions drawn from the present review are the distinct interconnectivity of the whole spectrum of molecular pathways and the prominent role of non-coding RNAs, especially circular RNAs, in the regulation of specific targets. All these new insights are discussed, even considering the topic of the resistance to therapy of gliomas, along with aspects that are still incompletely understood, like the role of hydroxymethylation, or even ferroptosis, in the pathobiology of gliomas.

[Neuropathology of pediatric brain tumors : Implications of the 5th edition of the WHO classification of central nervous system tumors]

BACKGROUND

Already with the update of the 4th edition of the World Health Organization (WHO) classification of tumors of the central nervous system, it was pointed out that pediatric diffuse glioma do not follow the same molecular mechanisms used to characterize adult diffuse glioma.

OBJECTIVES

What changes result from the update of the classification of tumors of the central nervous system?

METHODS

With the 5th edition of the WHO classification of tumors of the central nervous system, a second level of information containing molecular changes besides the histological characterization and grading of tumors was established.

RESULTS

A new classification of diffuse pediatric brain tumors based on molecular tumor pathways was established. The most important tumor pathways, considered for the new classification, were the activation of receptor tyrosine kinases and histone H3 alterations that cause epigenetic changes.

CONCLUSIONS

Increasingly better understanding of mechanisms in the development of pediatric brain tumors gives hope for more specific therapeutic approaches.

Gene Therapy for High Grade Glioma: The Clinical Experience

INTRODUCTION

High-grade gliomas (HGG) are the most common malignant primary brain tumors in adults, with a median survival of ~18 months. The standard of care (SOC) is maximal safe surgical resection, and radiation therapy with concurrent and adjuvant temozolomide. This protocol remains unchanged since 2005, even though HGG median survival has marginally improved.

AREAS COVERED

Gene therapy was developed as a promising approach to treat HGG. Here, we review completed and ongoing clinical trials employing viral and non-viral vectors for adult and pediatric HGG, as well as the key supporting preclinical data.

EXPERT OPINION

These therapies have proven safe, and pre- and post-treatment tissue analyses demonstrated tumor cell lysis, increased immune cell infiltration, and increased systemic immune function. Although viral therapy in clinical trials has not yet significantly extended the survival of HGG, promising strategies are being tested. Oncolytic HSV vectors have shown promising results for both adult and pediatric HGG. A recently published study demonstrated that HG47Δ improved survival in recurrent HGG. Likewise, PVSRIPO has shown survival improvement compared to historical controls. It is likely that further analysis of these trials will stimulate the development of new administration protocols, and new therapeutic combinations that will improve HGG prognosis.

New natural compound inhibitors of PDGFRA (platelet-derived growth factor receptor α) based on computational study for high-grade glioma therapy

Background

High-grade glioma (HGG) is a malignant brain tumor that is common and aggressive in children and adults. In the current medical paradigm, surgery and radiotherapy are the standard treatments for HGG patients. Despite this, the overall prognosis is still very bleak. Studies have shown that platelet-derived growth factor receptor α (PDGFRA) is an essential target to treat tumors and inhibiting the activity of PDGFRA can improve the prognosis of HGG. Thus, PDGFRA inhibitors are critical to developing drugs and cancer treatment.

Objective

The purpose of this study was to screen lead compounds and candidate drugs with potential inhibitors against platelet-derived growth factor receptor α (PDGFRA) from the drug library (ZINC database) in order to improve the prognosis of patients with high-grade glioma (HGG).

Materials and methods

In our study, we selected Imatinib as the reference drug. A series of computer-aided technologies, such as Discovery Studio 2019 and Schrodinger, were used to screen and assess potential inhibitors of PDGFRA. The first step was to calculate the LibDock scores and then analyze the pharmacological and toxicological properties. Following this, we docked the small molecules selected in the previous steps with PDGFRA to study their docking mechanism and affinity. In addition, molecular dynamics simulation was used to determine whether the ligand-PDGFRA complex was stable in nature.

Results

Two novel natural compounds 1 and 2 (ZINC000008829785 and ZINC000013377891) from the ZINC database were found binding to PDGFRA with more favorable interaction energy. Also, they were predicted with less Ames mutagenicity, rodent carcinogenicity, non-developmental toxic potential, and tolerant with cytochrome P450 2D6 (CYP2D6). The dynamic simulation analysis demonstrated that ZINC000008829785-PDGFRA and ZINC000013377891-PDGFRA dimer complex had more favorable potential energy compared with Imatinib, and they can exist in natural environments stably.

Conclusion

ZINC000008829785 and ZINC000013377891 might provide a solid foundation for drugs that inhibit PDGFRA in HGG. In addition to being safe drug candidates, these compounds had important implications for improving drugs targeting PDGFRA.