Advances in Targeting the Epidermal Growth Factor Receptor Pathway by Synthetic Products and Its Regulation by Epigenetic Modulators As a Therapy for Glioblastoma

Baicalein inhibits cell proliferation and induces apoptosis in brain glioma cells by downregulating the LGR4-EGFR pathway

Patients diagnosed with brain glioma have a poor prognosis and limited therapeutic options. LGR4 is overexpressed in brain glioma and involved in the tumorigenesis of many tumors. Baicalein (BAI) is a kind of flavonoid that has exhibited anti-tumor effects in various tumors. Nevertheless, the functions and associations of BAI and LGR4 in brain glioma remain unclear. In this study, Gene Expression Profiling Interactive Analysis and Human Protein Atlas databases were used to perform expression and survival analysis of LGR4 in brain glioma patients. Subsequently, the significance of LGR4-EGFR in brain glioma cells (HS683 and KNS89) and brain glioma animal models was explored by RNA interference and subcutaneous transplantation. Additionally, brain glioma cells were treated with BAI to explore the roles and mechanisms of BAI in brain glioma. The results showed that LGR4 was highly expressed in brain glioma and was related to a poor prognosis. LGR4 knockdown repressed the proliferation and EGFR phosphorylation but induced apoptosis in brain glioma cells. However, these effects were reversed by EGFR overexpression and CBL knockdown. In contrast, both in vitro and in vivo experiments revealed that LGR4 overexpression facilitated brain glioma cell malignant behavior and promoted tumor development, but these effects were rescued by BAI and an EGFR inhibitor. Furthermore, si-LGR4 accelerated EGFR protein degradation, while oe-LGR4 exhibited the opposite effect. Without affecting normal cellular viability, BAI inhibited malignant behavior, interacted with LGR4, and blocked the LGR4-EGFR pathway for brain glioma cells. In conclusion, our data suggested that BAI inhibited brain glioma cell proliferation and induced apoptosis by downregulating the LGR4-EGFR pathway, which provides a novel strategy and potential therapeutic targets to treat brain glioma.

Epidermal Growth Factor Receptor Inhibitors in Glioblastoma: Current Status and Future Possibilities

Glioblastoma, a grade 4 glioma as per the World Health Organization, poses a challenge in adult primary brain tumor management despite advanced surgical techniques and multimodal therapies. This review delves into the potential of targeting epidermal growth factor receptor (EGFR) with small-molecule inhibitors and antibodies as a treatment strategy. EGFR, a mutationally active receptor tyrosine kinase in over 50% of glioblastoma cases, features variants like EGFRvIII, EGFRvII and missense mutations, necessitating a deep understanding of their structures and signaling pathways. Although EGFR inhibitors have demonstrated efficacy in other cancers, their application in glioblastoma is hindered by blood-brain barrier penetration and intrinsic resistance. The evolving realm of nanodrugs and convection-enhanced delivery offers promise in ensuring precise drug delivery to the brain. Critical to success is the identification of glioblastoma patient populations that benefit from EGFR inhibitors. Tools like radiolabeled anti-EGFR antibody 806i facilitate the visualization of EGFR conformations, aiding in tailored treatment selection. Recognizing the synergistic potential of combination therapies with downstream targets like mTOR, PI3k, and HDACs is pivotal for enhancing EGFR inhibitor efficacy. In conclusion, the era of precision oncology holds promise for targeting EGFR in glioblastoma, contingent on tailored treatments, effective blood-brain barrier navigation, and the exploration of synergistic therapies.

Biomolecules to Biomarkers? U87MG Marker Evaluation on the Path towards Glioblastoma Multiforme Pathogenesis

The heterogeneity of the glioma subtype glioblastoma multiforme (GBM) challenges effective neuropathological treatment. The reliance on in vitro studies and xenografted animal models to simulate human GBM has proven ineffective. Currently, a dearth of knowledge exists regarding the applicability of cell line biomolecules to the realm of GBM pathogenesis. Our study's objectives were to address this preclinical issue and assess prominin-1, ICAM-1, PARTICLE and GAS5 as potential GBM diagnostic targets. The methodologies included haemoxylin and eosin staining, immunofluorescence, in situ hybridization and quantitative PCR. The findings identified that morphology correlates with malignancy in GBM patient pathology. Immunofluorescence confocal microscopy revealed prominin-1 in pseudo-palisades adjacent to necrotic foci in both animal and human GBM. Evidence is presented for an ICAM-1 association with degenerating vasculature. Significantly elevated nuclear PARTICLE expression from in situ hybridization and quantitative PCR reflected its role as a tumor activator. GAS5 identified within necrotic GBM validated this potential prognostic biomolecule with extended survival. Here we present evidence for the stem cell marker prominin-1 and the chemotherapeutic target ICAM-1 in a glioma animal model and GBM pathology sections from patients that elicited alternative responses to adjuvant chemotherapy. This foremost study introduces the long non-coding RNA PARTICLE into the context of human GBM pathogenesis while substantiating the role of GAS5 as a tumor suppressor. The validation of GBM biomarkers from cellular models contributes to the advancement towards superior detection, therapeutic responders and the ultimate attainment of promising prognoses for this currently incurable brain cancer.

Clinical Theranostics Trademark of Exosome in Glioblastoma Metastasis

Glioblastoma (GBM) is an aggressive type of cancer that has led to the death of a large population. The traditional approach fails to develop a solution for GBM's suffering life. Extensive research into tumor microenvironments (TME) indicates that TME extracellular vesicles (EVs) play a vital role in cancer development and progression. EVs are classified into microvacuoles, apoptotic bodies, and exosomes. Exosomes are the most highlighted domains in cancer research. GBM cell-derived exosomes participate in multiple cancer progression events such as immune suppression, angiogenesis, premetastatic niche formation (PMN), ECM (extracellular matrix), EMT (epithelial-to-mesenchymal transition), metastasis, cancer stem cell development and therapeutic and drug resistance. GBM exosomes also carry the signature of a glioblastoma-related status. The exosome-based GBM examination is part of the new generation of liquid biopsy. It also solved early diagnostic limitations in GBM. Traditional therapeutic approaches do not cross the blood-brain barrier (BBB). Exosomes are a game changer in GBM treatment and it is emerging as a potential platform for effective, efficient, and specific therapeutic development. In this review, we have explored the exosome-GBM interlink, the clinical impact of exosomes on GBM biomarkers, the therapeutics signature of exosomes in GBM, exosome-based research challenges, and future directions in GBM. Therefore, the GBM-derived exosomes offer unique therapeutic opportunities, which are currently under preclinical and clinical testing.

Transferrin receptor 1 targeted nanomedicine for brain tumor therapy

Achieving effective drug delivery to traverse the blood-brain barrier (BBB) and target tumor cells remains the greatest challenge for brain tumor therapy. Importantly, the overexpressed membrane receptors on the brain endothelial cells, especially transferrin receptor 1 (TfR1), which mediate their ligands/antibodies to overcome the BBB by transcytosis, have been emerging as promising targets for brain tumor therapy. By employing ligands (e.g., transferrin, H-ferritin), antibodies or targeting peptides of TfR1 or aptamers, various functional nano-formulations have been developed in the last decade. These agents showed great potential for the treatment of brain diseases due to their ideal size, high loading capacity, controlled drug release and suitable pharmacokinetics. Herein, we summarize the latest advances on TfR1-targeted nanomedicine for brain tumor therapy. Moreover, we also discuss the strategies of improving stability, targeting ability and accumulation of nano-formulations in brain tumors for better outcomes. In this review, we hope to provide inspiration for the rational design of TfR1-targeted nanomedicine against brain tumors.

Development of Glioblastoma from Stem Cells to a Full-Fledged Tumor

OBJECTIVE

IDH wild-type glioblastomas (GBM) are one of the most malignant and complex tumors for treatment. The urgent question of new therapeutic and diagnostic tools searching should be resolved based on cellular and molecular pathogenesis mechanisms, which remain insufficiently studied. In this study, we aimed to investigate GBM pathogenesis.

MATERIAL AND METHOD

/b > Using the isolation of different GBM cell populations and the cell cultures, animal models, and molecular genetic methods, we tried to clarify the picture of GBM pathogenesis by constructing a projection from different glioma stem cells types to an integral neoplasm.

RESULTS

We have shown a potential transformation pathway for both glioma stem cells and four definitive cell populations during gliomagenesis. Moreover, we have characterized each population, taking into account its place in the pathogenetic continuum, with a description of the most fundamental molecular and functional properties.

CONCLUSION

Finally, we have formed a complex holistic concept of the pathogenetic evolution of GBM at the cell-population level by integrating our results with the data of the world literature.

Latest updates on cellular and molecular biomarkers of gliomas

Gliomas are the most common central nervous system malignancies, compromising almost 80% of all brain tumors and is associated with significant mortality. The classification of gliomas has shifted from basic histological perspective to one that is based on molecular biomarkers. Treatment of this type of tumors consists currently of surgery, chemotherapy and radiation therapy. During the past years, there was a limited development of effective glioma diagnostics and therapeutics due to multiple factors including the presence of blood-brain barrier and the heterogeneity of this type of tumors. Currently, it is necessary to highlight the advantage of molecular diagnosis of gliomas to develop patient targeted therapies based on multiple oncogenic pathway. In this review, we will evaluate the development of cellular and molecular biomarkers for the diagnosis of gliomas and the impact of these diagnostic tools for better tailored and targeted therapies.

Molecular and Circulating Biomarkers in Patients with Glioblastoma

Glioblastoma is the most aggressive malignant tumor of the central nervous system with a low survival rate. The difficulty of obtaining this tumor material represents a major limitation, making the real-time monitoring of tumor progression difficult, especially in the events of recurrence or resistance to treatment. The identification of characteristic biomarkers is indispensable for an accurate diagnosis, the rigorous follow-up of patients, and the development of new personalized treatments. Liquid biopsy, as a minimally invasive procedure, holds promise in this regard. The purpose of this paper is to summarize the current literature regarding the identification of molecular and circulating glioblastoma biomarkers and the importance of their integration as a valuable tool to improve patient care.

Epigenetic Influences on Wound Healing and Hypertrophic-Keloid Scarring: A Review for Basic Scientists and Clinicians

Primary care physicians and dermatologists are challenged by patients affected by keloid or hypertrophic scarring resulting from accidental wounding, surgical incisions, tattooing, or “branding” procedures to demonstrate their association with a specific culture, fraternity, or cult. The dysregulated wound healing associated with keloids and hypertrophic scarring adversely affects genetically susceptible individuals, especially persons of color with Fitzpatrick Skin types IV-VI. Although the specific mechanisms of bulky hypertrophic/keloid scarring and its association with oxidative stress and inflammation remain unclear, the current knowledge base is sufficient to provide some guidance to health practitioners who must serve, treat, and counsel affected individuals. This review focuses on providing insight to healthcare professionals about the role of epigenetics, oxidative stress, poor local oxygenation, and its relationship to impaired wound healing. The goal is to promote further research on bulky hypertrophic and keloid scarring for its prevention and to develop evidence-based clinical guidelines for optimal treatment.

Design, synthesis, and in vitro antitumor activity of 6-aryloxyl substituted quinazoline derivatives

Quinazoline derivatives are a class of important antitumor drugs known as small molecule inhibitors that include epidermal growth factor receptor (EGFR) inhibitors. Based on the structure of poziotinib, a series of 6-aryloxyl substituted quinazoline derivatives were designed and synthesized. The in vitro antitumor activities of the compounds were evaluated by the 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) method using the human gastric cancer N87 (HER2), nonsmall-cell lung cancer H1975 (EGFRT790M/L858R), and A549 (EGFRWT) cell lines. The most promising compound 4m exhibited potent antitumoral activities with IC50 values of 6.3 nM and 7.5 nM for N87 and H1975 cell lines, respectively. Meanwhile, it was less potent against A549 cancer cells with an IC50 value of 29.9 μM. The molecular docking results suggested that compound 4m has different binding modes to the wild-type and mutated EGFR.

Quantitative Analysis of Serum Zinc Levels in Primary Brain Tumor Patients

Although the close relationships between most of the trace elements and tumor formation mechanisms are very well-defined, studies on some elements such as zinc are still ongoing. When examining studies on brain tumors, it was observed that studies investigating the role played by serum zinc levels on tumor etiology and prognosis have gained momentum. In this study, we investigate the relationship between different brain tumor types and serum zinc levels by quantitatively analyzing serum zinc levels in patients with primary brain tumors. In this study, we measured serum zinc levels of 33 brain tumor patients as well as 35 healthy individuals serving as a control group. Metal concentrations were measured using atomic absorption spectrophotometry. Serum zinc levels were lower in patients with primary brain tumors compared to control group (p < 0.05). Additionally, patients' serum zinc levels were significantly different according to their brain tumor types and also according to their age (p < 0.05). Our findings suggest that brain tumor patients' serum zinc levels may play a role in tumor etiology, typology, and prognosis.

Suppression of PI3K/Akt/mTOR pathway in chrysoeriol-induced apoptosis of rat C6 glioma cells

Chrysoeriol, a dietary methoxyflavonoid which is found in tropical medicinal plants, has been shown to have antioxidant, anti-inflammatory, and antineoplastic properties. The present study aimed to investigate the effects of chrysoeriol and its related mechanisms in rat C6 glioma cells. Cell viability in rat C6 glioma cells were measured by MTT assay. The protein expression levels of cleaved caspase-3, caspase-3, pro-apoptotic (Bax), anti-apoptotic protein (Bcl-2), and Annexin V were detected by Western blot analysis and immunocytochemical staining. Results showed that chrysoeriol significantly decreased cell viability and induced apoptosis in rat C6 glioma cells. Chrysoeriol significantly increased the levels of Bax/Bcl-2 ratio and cleaved caspase-3/caspase-3 ratio. Moreover, treatment with chrysoeriol significantly reduced the phosphorylation of PI3K, Akt, and mTOR expression in ratios. These results suggest that chrysoeriol promote apoptosis in rat C6 glioma cells via suppression of the PI3K/Akt/mTOR signaling pathway, thereby demonstrating the potential antineoplastic effects of chrysoeriol on glioma cells.

Unconventional non-amino acidic PET radiotracers for molecular imaging in gliomas

PURPOSE

The objective of this review was to explore the potential clinical application of unconventional non-amino acid PET radiopharmaceuticals in patients with gliomas.

METHODS

A comprehensive search strategy was used based on SCOPUS and PubMed databases using the following string: ("perfusion" OR "angiogenesis" OR "hypoxia" OR "neuroinflammation" OR proliferation OR invasiveness) AND ("brain tumor" OR "glioma") AND ("Positron Emission Tomography" OR PET). From all studies published in English, the most relevant articles were selected for this review, evaluating the mostly used PET radiopharmaceuticals in research centers, beyond amino acid radiotracers and 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG), for the assessment of different biological features, such as perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological characteristics in patients with glioma.

RESULTS

At present, the use of non-amino acid PET radiopharmaceuticals specifically designed to assess perfusion, angiogenesis, hypoxia, neuroinflammation, cell proliferation, tumor invasiveness, and other biological features in glioma is still limited.

CONCLUSION

The use of investigational PET radiopharmaceuticals should be further explored considering their promising potential and studies specifically designed to validate these preliminary findings are needed. In the clinical scenario, advancements in the development of new PET radiopharmaceuticals and new imaging technologies (e.g., PET/MR and the application of the artificial intelligence to medical images) might contribute to improve the clinical translation of these novel radiotracers in the assessment of gliomas.

Prognostic and Predictive Biomarkers in Gliomas

Gliomas are the most common central nervous system tumors. New technologies, including genetic research and advanced statistical methods, revolutionize the therapeutic approach to the patient and reveal new points of treatment options. Moreover, the 2021 World Health Organization Classification of Tumors of the Central Nervous System has fundamentally changed the classification of gliomas and incorporated many molecular biomarkers. Given the rapid progress in neuro-oncology, here we compile the latest research on prognostic and predictive biomarkers in gliomas. In adult patients, IDH mutations are positive prognostic markers and have the greatest prognostic significance. However, CDKN2A deletion, in IDH-mutant astrocytomas, is a marker of the highest malignancy grade. Moreover, the presence of TERT promoter mutations, EGFR alterations, or a combination of chromosome 7 gain and 10 loss upgrade IDH-wildtype astrocytoma to glioblastoma. In pediatric patients, H3F3A alterations are the most important markers which predict the worse outcome. MGMT promoter methylation has the greatest clinical significance in predicting responses to temozolomide (TMZ). Conversely, mismatch repair defects cause hypermutation phenotype predicting poor response to TMZ. Finally, we discussed liquid biopsies, which are promising diagnostic, prognostic, and predictive techniques, but further work is needed to implement these novel technologies in clinical practice.

A Rational Designed Novel Bispecific Antibody for the Treatment of GBM

Epidermal growth factor receptor variant III (EGFRvIII) is highly and specifically expressed in a subset of lethal glioblastoma (GBM), making the receptor a unique therapeutic target for GBM. Recently, bispecific antibodies (BsAbs) have shown exciting clinical benefits in cancer immunotherapy. Here, we report remarkable results for GBM treatment with a BsAb constructed by the "BAPTS" method. The BsAb was characterized through LC/MS, SEC-HPLC, and SPR. Furthermore, the BsAb was evaluated in vitro for bioactivities through FACS, antigen-dependent T-cell-mediated cytotoxicity, and a cytokine secretion assay, as well as in vivo for antitumor activity and pharmacokinetic (PK) parameters through immunodeficient NOD/SCID and BALB/c mouse models. The results indicated that the EGFRvIII-BsAb eliminated EGFRvIII-positive GBM cells by recruiting and stimulating effector T cells secreting cytotoxic cytokines that killed GBM cells in vitro. The results demonstrated the antitumor potential and long circulation time of EGFRvIII-BsAb in NOD/SCID mice bearing de2-7 subcutaneously heterotopic transplantation tumors and BALB/c mice. In conclusion, our experiments in both in vitro and in vivo have shown the remarkable antitumor activities of EGFRvIII-BsAb, highlighting its potential in clinical applications for the treatment of GBM. Additional merits, including a long circulation time and low immunogenicity, have also made the novel BsAb a promising therapeutic candidate.

Potential new targets and drugs related to histone modifications in glioma treatment

Glioma accounts for 40-50% of craniocerebral tumors, whose outcome rarely improves after standard treatment. The development of new therapeutic targets for glioma treatment has important clinical significance. With the deepening of research on gliomas, recent researchers have found that the occurrence and development of gliomas is closely associated with histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination. Additionally, evidence has confirmed the close relationship between histone modifications and temozolomide (TMZ) resistance. Therefore, histone modification-related proteins have been widely recognized as new therapeutic targets for glioma treatment. In this review, we summarize the potential histone modification-associated targets and related drugs for glioma treatment. We have further clarified how histone modifications regulate the pathogenesis of gliomas and the mechanism of drug action, providing novel insights for the current clinical glioma treatment. Herein, we have also highlighted the limitations of current clinical therapies and have suggested future research directions and expected advances in potential areas of disease prognosis. Due to the complicated glioma pathogenesis, in the present review, we have acknowledged the limitations of histone modification applications in the related clinical treatment.

Design, synthesis and biological evaluation of sulfamoylphenyl-quinazoline derivatives as potential EGFR/CAIX dual inhibitors

Multi-target, especially dual-target, drug design has become a popular research field for cancer treatment. Development of small molecule dual-target inhibitors through hybridization strategy can provide highly potent and selective anticancer agents. In this study, three series of quinazoline derivatives bearing a benzene-sulfonamide moiety were designed and synthesized as dual EGFR/CAIX inhibitors. All the synthesized compounds were evaluated against epidermoid carcinoma (A431) and non-small cell lung cancer (A549 and H1975) cell lines, which displayed weak to potent anticancer activity. In particular, compound 8v emerged as the most potent derivative against mutant-type H1975 cells, which exhibited comparable activity to osimertinib. Importantly, 8v exhibited stronger anti-proliferative activity than osimertinib against H1975 cells under hypoxic condition. Kinase inhibition studies indicated that 8v showed excellent inhibitory effect on EGFR^T790M enzyme, which was 41 times more effective than gefitinib and almost equal to osimertinib. Mechanism studies revealed that 8v exhibited remarkable CAIX inhibitory effect comparable to acetazolamide and significantly inhibited the expression of p-EGFR as well as its downstream p-AKT and p-ERK in H1975 cells. Notably, 8v was found to inhibit the expression of CAIX and its upstream HIF-1α in H1975 cells under hypoxic condition. Molecular docking was also performed to gain insights into the ligand-binding interactions of 8v inside EGFR^WT, EGFR^T790M and CAIX binding sites.

Glioblastoma Break-in; Try Something New

Context: Glioblastoma is the most invasive brain tumor with a poor prognosis and rapid progression. The standard therapy (surgical resection, adjuvant chemotherapy, and radiotherapy) ensures survival only up to 18 months. In this article, we focus on innovative types of radiotherapy, various combinations of temozolomide with novel substances, and methods of their administration and vector delivery to tumor cells. Evidence Acquisition: For a detailed study of the various options for chemotherapy and radiotherapy, Elsevier, NCBI MedLine, Scopus, Google Scholar, Embase, Web of Science, The Cochrane Library, EMBASE, Global Health, CyberLeninka, and RSCI databases were analyzed. Results: The most available method is oral or intravenous administration of temozolomide. More efficient is the combined chemotherapy of temozolomide with innovative drugs and substances such as lomustine, histone deacetylase inhibitors, and chloroquine, as well as olaparib. These combinations improve patient survival and are effective in the treatment of resistant tumors. Compared to standard fractionated radiotherapy (60 Gy, 30 fractions, 6 weeks), hypofractionated is more effective for elderly patients due to lack of toxicity; brachytherapy reduces the risk of glioblastoma recurrence, while radiosurgery with bevacizumab is more effective against recurrent or inoperable tumors. Currently, the most effective treatment is considered to be the intranasal administration of anti-Ephrin A3 (anti-EPHA3)-modified containing temozolomide butyl ester-loaded (TBE-loaded) poly lactide-co-glycolide nanoparticles (P-NPs) coated with N-trimethylated chitosan (TMC) to overcome nasociliary clearance. Conclusions: New radiotherapeutic methods significantly increase the survival rates of glioblastoma patients. With some improvement, it may lead to the elimination of all tumor cells leaving the healthy alive. New chemotherapeutic drugs show impressive results with adjuvant temozolomide. Anti-EPHA3-modified TBE-loaded P-NPs coated with TMC have high absorption specificity and kill glioblastoma cells effectively. A new “step forward” may become a medicine of the future, which reduces the specific accumulation of nanoparticles in the lungs, but simultaneously does not affect specific absorption by tumor cells.

Hybrid Quinazoline 1,3,5-Triazines as Epidermal Growth Factor Receptor (EGFR) Inhibitors with Anticancer Activity: Design, Synthesis, and Computational Study

We report a series of hybrid quinazoline-1,3,5-triazine derivatives as EGFR inhibitors, which were synthesised and tested by using a variety of in vitro, in silico, and in vivo techniques. The derivatives were found to be active against different cancer cell lines and nontoxic against normal ones, with compounds 7 c, 7 d, 7 e, and 7 j being the most potent ones. The derivatives were also evaluated for angiogenesis inhibition potency in chicken eggs, and molecular docking and dynamics simulation studies were carried out to elucidate the fundamental substituent groups essential for their bioactivity. Additionally, a SAR study of the derivatives was performed for future compound optimisation. These studies suggested that the derivatives have a high affinity towards EGFR with favourable pharmacological properties. The most active compound (7 e) was further evaluated for in vivo anticancer activity against DMBA-induced tumours in female Sprague-Dawley rats as well as its effects on plasma antioxidant status, biotransformation enzymes, and lipid profile. The study suggested that 7 e has lead properties against breast cancer and can serve as a starting compound for further development of anti-EGFR compounds.

The Roles of miRNA in Glioblastoma Tumor Cell Communication: Diplomatic and Aggressive Negotiations

Glioblastoma (GBM) consists of a heterogeneous collection of competing cellular clones which communicate with each other and with the tumor microenvironment (TME). MicroRNAs (miRNAs) present various exchange mechanisms: free miRNA, extracellular vesicles (EVs), or gap junctions (GJs). GBM cells transfer miR-4519 and miR-5096 to astrocytes through GJs. Oligodendrocytes located in the invasion front present high levels of miR-219-5p, miR-219-2-3p, and miR-338-3p, all related to their differentiation. There is a reciprocal exchange between GBM cells and endothelial cells (ECs) as miR-5096 promotes angiogenesis after being transferred into ECs, whereas miR-145-5p acts as a tumor suppressor. In glioma stem cells (GSCs), miR-1587 and miR-3620-5p increase the proliferation and miR-1587 inhibits the hormone receptor co-repressor-1 (NCOR1) after EVs transfers. GBM-derived EVs carry miR-21 and miR-451 that are up-taken by microglia and monocytes/macrophages, promoting their proliferation. Macrophages release EVs enriched in miR-21 that are transferred to glioma cells. This bidirectional miR-21 exchange increases STAT3 activity in GBM cells and macrophages, promoting invasion, proliferation, angiogenesis, and resistance to treatment. miR-1238 is upregulated in resistant GBM clones and their EVs, conferring resistance to adjacent cells via the CAV1/EGFR signaling pathway. Decrypting these mechanisms could lead to a better patient stratification and the development of novel target therapies.

Exploring Novel Molecular Targets for the Treatment of High-Grade Astrocytomas Using Peptide Therapeutics: An Overview

Diffuse astrocytomas are the most aggressive and lethal glial tumors of the central nervous system (CNS). Their high cellular heterogeneity and the presence of specific barriers, i.e., blood–brain barrier (BBB) and tumor barrier, make these cancers poorly responsive to all kinds of currently available therapies. Standard therapeutic approaches developed to prevent astrocytoma progression, such as chemotherapy and radiotherapy, do not improve the average survival of patients. However, the recent identification of key genetic alterations and molecular signatures specific for astrocytomas has allowed the advent of novel targeted therapies, potentially more efficient and characterized by fewer side effects. Among others, peptides have emerged as promising therapeutic agents, due to their numerous advantages when compared to standard chemotherapeutics. They can be employed as (i) pharmacologically active agents, which promote the reduction of tumor growth; or (ii) carriers, either to facilitate the translocation of drugs through brain, tumor, and cellular barriers, or to target tumor-specific receptors. Since several pathways are normally altered in malignant gliomas, better outcomes may result from combining multi-target strategies rather than targeting a single effector. In the last years, several preclinical studies with different types of peptides moved in this direction, providing promising results in murine models of disease and opening new perspectives for peptide applications in the treatment of high-grade brain tumors.

Discovery of Potent and Selective Epidermal Growth Factor Receptor (EGFR) Bifunctional Small-Molecule Degraders

Several epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have been developed and approved by Food and Drug Administration for the treatment of non-small-cell lung cancers, but their efficacy can be compromised by acquired drug resistance conferred by EGFR-mutant variants. Here, we described the discovery of a novel E3 ligase von Hippel-Lindau-recruiting EGFR degrader, MS39 (compound 6), and a first-in-class E3 ligase cereblon-recruiting EGFR degrader, MS154 (compound 10), using the proteolysis targeting chimera technology. These compounds potently induced the degradation of mutant but not wild-type EGFR in an E3 ligase-dependent manner in cancer cell lines and effectively suppressed the growth of lung cancer cells compared with the corresponding negative controls. The global proteomic analyses revealed that the compounds were highly selective for EGFR. Furthermore, both compounds were bioavailable in mouse pharmacokinetic studies, and compound 6 is the first EGFR degrader suitable for in vivo efficacy studies. Overall, we provide a set of well-characterized chemical tools to the research community.

Novel approaches for glioblastoma treatment: Focus on tumor heterogeneity, treatment resistance, and computational tools

BACKGROUND

Glioblastoma (GBM) is a highly aggressive primary brain tumor. Currently, the suggested line of action is the surgical resection followed by radiotherapy and treatment with the adjuvant temozolomide, a DNA alkylating agent. However, the ability of tumor cells to deeply infiltrate the surrounding tissue makes complete resection quite impossible, and, in consequence, the probability of tumor recurrence is high, and the prognosis is not positive. GBM is highly heterogeneous and adapts to treatment in most individuals. Nevertheless, these mechanisms of adaption are unknown.

RECENT FINDINGS

In this review, we will discuss the recent discoveries in molecular and cellular heterogeneity, mechanisms of therapeutic resistance, and new technological approaches to identify new treatments for GBM. The combination of biology and computer resources allow the use of algorithms to apply artificial intelligence and machine learning approaches to identify potential therapeutic pathways and to identify new drug candidates.

CONCLUSION

These new approaches will generate a better understanding of GBM pathogenesis and will result in novel treatments to reduce or block the devastating consequences of brain cancers.

MYST1/KAT8 contributes to tumor progression by activating EGFR signaling in glioblastoma cells

With short survival time, glioblastoma (GBM) is the most malignant tumor in the central nervous system. Recently, epigenetic enzymes play essential roles in the regulation of tumorigenesis and cancer development of GBM. However, little is known about MYST1/KAT8/MOF, a histone acetylation enzyme, in GBM. The present study shows that MYST1 promotes GBM progression through activating epidermal growth factor receptor (EGFR) signaling. MYST1 expression was increased in GBM and was negatively correlated with prognosis in patients with glioma and GBM. Knockdown of MYST1 reduced cell proliferation and BrdU incorporation in LN229, U87, and A172 GBM cells. Besides, MYST1 downregulation also induced cell cycle arrest at G2M phase, as well as the reduced expression of CDK1, Cyclin A, Cyclin B1, and increased expression of p21^CIP1/Waf1. Meanwhile, Self‐renewal capability in vitro and tumorigenecity in vivo were also impaired after MYST1 knockdown. Importantly, MYST1 expression was lowly expressed in mesenchymal subtype of GBM and was positively correlated with EGFR expression in a cohort from The Cancer Genome Atlas. Western blot subsequently confirmed that phosphorylation and activation of p‐Try1068 of EGFR, p‐Ser473 of AKT and p‐Thr202/Tyr204 of Erk1/2 were also decreased by MYST1 knockdown. Consistent with the results above, overexpression of MYST1 promoted GBM growth and activated EGFR signaling in vitro and in vivo. In addition, erlotinib, a US Food and Drug Administration approved cancer drug which targets EGFR, was able to rescue MYST1‐promoted cell proliferation and EGFR signaling pathway. Furthermore, the transcription of EGF, an EFGR ligand, was shown to be positively regulated by MYST1 possibly via H4K16 acetylation. Our findings elucidate MYST1 as a tumor promoter in GBM and an EGFR activator, and may be a potential drug target for GBM treatment.