EGFR, the Lazarus target for precision oncology in glioblastoma

Current status of precision oncology in adult glioblastoma

The concept of precision oncology, the application of targeted drugs based on comprehensive molecular profiling, has revolutionized treatment strategies in oncology. This review summarizes the current status of precision oncology in glioblastoma (GBM), the most common and aggressive primary brain tumor in adults with a median survival below 2 years. Targeted treatments without prior target verification have consistently failed. Patients with BRAF V600E-mutated GBM benefit from BRAF/MEK-inhibition, whereas targeting EGFR alterations was unsuccessful due to poor tumor penetration, tumor cell heterogeneity, and pathway redundancies. Systematic screening for actionable molecular alterations resulted in low rates (< 10%) of targeted treatments. Efficacy was observed in one-third and currently appears to be limited to BRAF-, VEGFR-, and mTOR-directed treatments. Advancing precision oncology for GBM requires consideration of pathways instead of single alterations, new trial concepts enabling rapid and adaptive drug evaluation, a focus on drugs with sufficient bioavailability in the CNS, and the extension of target discovery and validation to the tumor microenvironment, tumor cell networks, and their interaction with immune cells and neurons.

VGLL1 stabilization of cytoplasmic TAZ promotes EGFR expression and maintains tumor initiating cells in breast cancer independent of TEAD

Vestigial-like family member 1 (VGLL1) is one of the X-linked genes whose expression is elevated in basal-like breast cancer (BLBC) because of X-chromosome isodisomy. As an approach towards understanding its function, we performed correlation study using transcript data of breast cancer patients from cBioPortal for Cancer Genomics. Our analysis identified EGFR as the most correlated transcript with VGLL1. We demonstrate that VGLL1 promotes EGFR expression and increases the frequency of breast tumor initiating cells (CD44high/+CD24low/-). These findings are crucial because an elevated EGFR expression and high frequency of CD44high/+CD24low/- cells are defining features of BLBC, and we provide a new mechanistic insight into how their expressions are controlled. Importantly, VGLL1 regulation of EGFR and CD44high/+CD24low/- population is mediated by the hippo-transducer TAZ which exerts its oncogenic roles by binding and activating TEAD transcription factors. A crucial finding is that TEAD-binding domain of TAZ is dispensable for its regulation of EGFR and CD44high/+CD24low/- cells. Instead, VGLL1 stabilization of cytoplasmic TAZ is essential for these functions. Also, we show that VGLL1/TAZ restricts the surface expression of CD24 which contributes to the increased number of CD44high/+CD24low/- cells. In addition, we observed that VGLL1 represses AXL expression and suppresses claudin-low phenotype, and that is caused by the VGLL1 mediated nuclear expulsion of TAZ. Therefore, EGFR and AXL seem to represent two different breast tumor subtypes, and their differential expressions is controlled by VGLL1.

Signature reversion of three disease-associated gene signatures prioritizes cancer drug repurposing candidates

Drug repurposing is promising because approving a drug for a new indication requires fewer resources than approving a new drug. Signature reversion detects drug perturbations most inversely related to the disease-associated gene signature to identify drugs that may reverse that signature. We assessed the performance and biological relevance of three approaches for constructing disease-associated gene signatures (i.e., limma, DESeq2, and MultiPLIER) and prioritized the resulting drug repurposing candidates for four low-survival human cancers. Our results were enriched for candidates that had been used in clinical trials or performed well in the PRISM drug screen. Additionally, we found that pamidronate and nimodipine, drugs predicted to be efficacious against the brain tumor glioblastoma (GBM), inhibited the growth of a GBM cell line and cells isolated from a patient-derived xenograft (PDX). Our results demonstrate that by applying multiple disease-associated gene signature methods, we prioritized several drug repurposing candidates for low-survival cancers.

AGCM-22, a novel cetuximab-based EGFR-targeting antibody-drug-conjugate with highly selective anti-glioblastoma efficacy

The epidermal growth factor receptor (EGFR) has received significant attention as a potential target for glioblastoma (GBM) therapeutics in the past two decades. However, although cetuximab, an antibody that specifically targets EGFR, exhibits a high affinity for EGFR, it has not yet been applied in the treatment of GBM. Antibody-drug conjugates (ADCs) utilize tumor-targeting antibodies for the selective delivery of cytotoxic drugs, resulting in improved efficacy compared to conventional chemotherapy drugs. However, the effectiveness of cetuximab as a targeted antibody for ADCs in the treatment of GBM remains uncertain. In this study, we synthesized AGCM-22, an EGFR-targeted ADC derived from cetuximab, by conjugating it with the tubulin inhibitor monomethyl auristatin E (MMAE) using our Valine-Alanine Cathepsin B cleavable linker. In vitro experiments demonstrated that AGCM-22 effectively inhibited GBM cell proliferation through increased levels of apoptosis and autophagy-related cell death, whereas cetuximab alone had no anti-GBM effects. Additionally, both mouse and human orthotopic tumor models exhibited the selective tumor-targeting efficacy of AGCM-22, along with favorable metabolic properties and superior anti-GBM activity compared to temozolomide (TMZ). In summary, this study presents a novel ADC for GBM therapy that utilizes cetuximab as the tumor-targeting antibody, resulting in effective delivery of the cytotoxic drug payload.

Glioblastoma Therapy: Past, Present and Future

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

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.

Machine learning in onco-pharmacogenomics: a path to precision medicine with many challenges

Over the past two decades, Next-Generation Sequencing (NGS) has revolutionized the approach to cancer research. Applications of NGS include the identification of tumor specific alterations that can influence tumor pathobiology and also impact diagnosis, prognosis and therapeutic options. Pharmacogenomics (PGx) studies the role of inheritance of individual genetic patterns in drug response and has taken advantage of NGS technology as it provides access to high-throughput data that can, however, be difficult to manage. Machine learning (ML) has recently been used in the life sciences to discover hidden patterns from complex NGS data and to solve various PGx problems. In this review, we provide a comprehensive overview of the NGS approaches that can be employed and the different PGx studies implicating the use of NGS data. We also provide an excursus of the ML algorithms that can exert a role as fundamental strategies in the PGx field to improve personalized medicine in cancer.

From signalling pathways to targeted therapies: unravelling glioblastoma's secrets and harnessing two decades of progress

Glioblastoma, a rare, and highly lethal form of brain cancer, poses significant challenges in terms of therapeutic resistance, and poor survival rates for both adult and paediatric patients alike. Despite advancements in brain cancer research driven by a technological revolution, translating our understanding of glioblastoma pathogenesis into improved clinical outcomes remains a critical unmet need. This review emphasises the intricate role of receptor tyrosine kinase signalling pathways, epigenetic mechanisms, and metabolic functions in glioblastoma tumourigenesis and therapeutic resistance. We also discuss the extensive efforts over the past two decades that have explored targeted therapies against these pathways. Emerging therapeutic approaches, such as antibody-toxin conjugates or CAR T cell therapies, offer potential by specifically targeting proteins on the glioblastoma cell surface. Combination strategies incorporating protein-targeted therapy and immune-based therapies demonstrate great promise for future clinical research. Moreover, gaining insights into the role of cell-of-origin in glioblastoma treatment response holds the potential to advance precision medicine approaches. Addressing these challenges is crucial to improving outcomes for glioblastoma patients and moving towards more effective precision therapies.

Epigenomic perturbation of novel EGFR enhancers reduces the proliferative and invasive capacity of glioblastoma and increases sensitivity to temozolomide

BACKGROUND

Glioblastoma (GB) is the most aggressive of all primary brain tumours and due to its highly invasive nature, surgical resection is nearly impossible. Patients typically rely on radiotherapy with concurrent temozolomide (TMZ) treatment and face a median survival of ~ 14 months. Alterations in the Epidermal Growth Factor Receptor gene (EGFR) are common in GB tumours, but therapies targeting EGFR have not shown significant clinical efficacy.

METHODS

Here, we investigated the influence of the EGFR regulatory genome on GB cells and identified novel EGFR enhancers located near the GB-associated SNP rs723527. We used CRISPR/Cas9-based approaches to target the EGFR enhancer regions, generating multiple modified GB cell lines, which enabled us to study the functional response to enhancer perturbation.

RESULTS

Epigenomic perturbation of the EGFR regulatory region decreases EGFR expression and reduces the proliferative and invasive capacity of glioblastoma cells, which also undergo a metabolic reprogramming in favour of mitochondrial respiration and present increased apoptosis. Moreover, EGFR enhancer-perturbation increases the sensitivity of GB cells to TMZ, the first-choice chemotherapeutic agent to treat glioblastoma.

CONCLUSIONS

Our findings demonstrate how epigenomic perturbation of EGFR enhancers can ameliorate the aggressiveness of glioblastoma cells and enhance the efficacy of TMZ treatment. This study demonstrates how CRISPR/Cas9-based perturbation of enhancers can be used to modulate the expression of key cancer genes, which can help improve the effectiveness of existing cancer treatments and potentially the prognosis of difficult-to-treat cancers such as glioblastoma.

Neuroblastoma and Glioblastoma Cases With Amplified Oncogenes Have Reduced Numbers of Tumor-Resident Adaptive Immune Receptor Recombinations

PURPOSE

In certain cancers, oncogene amplification is correlated with an immunologically cold or noninflamed, tumor immune microenvironment (TIME) and a worse prognosis, for example, in the case of MYCN-amplified neuroblastoma (NBL). However, for other cancer types, the relationship between oncogene amplification and immune response is more complicated or unresolved. One such cancer is glioblastoma multiforme (GBM), in which the epidermal growth factor receptor (EGFR) oncogene is commonly amplified. Unlike MYCN-amplified NBL, EGFR-amplified GBM has not been shown to correlate with a distinct survival probability.

METHODS

Given this contrasting state for NBL and GBM, we sought to apply a genomics approach to evaluating the immune response for cases with gene amplification.

RESULTS

Our results confirmed and added further specificity to the cold TIME of MYCN-amplified NBL. Moreover, we demonstrated a novel state of immunologically cold EGFR-amplified GBM tumors.

CONCLUSION

This approach to using copy number variation and immune receptor recombination read recovery levels to assess gene amplification and TIME, respectively, may be particularly efficient for the rapid evaluation of many other cancer types.

Special Issue: Principal Challenges in the Adjuvant Treatment of Glioblastoma

Despite advances in local treatments, such as supramaximal resection (even in eloquent locations [...].

Personalized Medicine in Brain Gliomas: Targeted Therapy, Patient-Derived Tumor Models (Review)

Gliomas are the most common type of primary malignant brain tumors. The choice of treatments for these tumors was quite limited for many years, and therapy results generally remain still unsatisfactory. Recently, a significant breakthrough in the treatment of many forms of cancer occurred when personalized targeted therapies were introduced which inhibit tumor growth by affecting a specific molecular target. Another trend gaining popularity in oncology is the creation of patient-derived tumor models which can be used for drug screening to select the optimal therapy regimen. Molecular and genetic mechanisms of brain gliomas growth are considered, consisting of individual components which could potentially be exposed to targeted drugs. The results of the literature review show a higher efficacy of the personalized approach to the treatment of individual patients compared to the use of standard therapies. However, many unresolved issues remain in the area of predicting the effectiveness of a particular drug therapy regimen. The main hopes in solving this issue are set on the use of patient-derived tumor models, which can be used in one-stage testing of a wide range of antitumor drugs.

The Role of EGFR Amplification in Deep Venous Thrombosis Occurrence in IDH Wild-Type Glioblastoma

Introduction: Glioblastoma (GBM) patients have a 20-30 incidence of venous thromboembolic events. EGFR is a widely used prognostic marker for many cancers. Recent lung cancer studies have described relationships between EGFR amplification and an increased incidence of thromboembolic complications. We aim to explore this relationship in glioblastoma patients. Methods: Two hundred ninety-three consecutive patients with IDH wild-type GBM were included in the analysis. The amplification status of EGFR was measured using fluorescence in situ hybridization (FISH). Centromere 7 (CEP7) expression was recorded to calculate the EGFR-to-CEP7 ratio. All data were collected retrospectively through chart review. Molecular data were obtained through the surgical pathology report at the time of biopsy. Results: There were 112 subjects who were EGFR-amplified (38.2%) and 181 who were non-amplified (61.8%). EGFR amplification status was not significantly correlated with VTE risk overall (p = 0.2001). There was no statistically significant association between VTE and EGFR status after controlling for Bevacizumab therapy (p = 0.1626). EGFR non-amplified status was associated with an increased VTE risk in subjects greater than 60 years of age (p = 0.048). Conclusions: There was no significant difference in occurrence of VTE in patients with glioblastoma, regardless of EGFR amplification status. Patients older than 60 years of age with EGFR amplification experienced a lower rate of VTE, contrary to some reports on non-small-cell lung cancer linking EGFR amplification to VTE risk.