Glioblastoma Tumor Microenvironment: An Important Modulator for Tumoral Progression and Therapy Resistance.

The race to find an effective treatment for glioblastoma (GBM) remains a critical topic, because of its high aggressivity and impact on survival and the quality of life. Currently, due to GBM's high heterogeneity, the conventional treatment success rate and response to therapy are relatively low, with a median survival rate of less than 20 months. A new point of view can be provided by the comprehension of the tumor microenvironment (TME) in pursuance of the development of new therapeutic strategies to aim for a longer survival rate with an improved quality of life and longer disease-free interval (DFI). The main components of the GBM TME are represented by the extracellular matrix (ECM), glioma cells and glioma stem cells (GSCs), immune cells (microglia, macrophages, neutrophils, lymphocytes), neuronal cells, all of them having dynamic interactions and being able to influence the tumoral growth, progression, and drug resistance thus being a potential therapeutic target. This paper will review the latest research on the GBM TME and the potential therapeutic targets to form an up-to-date strategy.

Evaluation of Single and Combined Temozolomide and Doxorubicin Treatment Responses in Low- and High-Grade Glioma In Vitro.

BACKGROUND: Astrocytoma, the most common type of glioma, can histologically be low or high grade. Treatment recommendations for astrocytic tumors are based on the histopathological and molecular phenotype. For grade 2 astrocytoma, the combination of radiotherapy and adjuvant chemotherapy with procarbazine, lomustine, and vincristine (PCV) is better than radiotherapy alone. Temozolomide (TMZ) is being increasingly recognized as a replacement for PCV in brain tumor therapy, due to the lower myelotoxicity. TMZ is currently a well-established first-line treatment for grade 3 astrocytoma, grade 4 astrocytoma, and glioblastoma and it is also sporadically used for grade 2 astrocytoma. However, TMZ faces multiple challenges such as adverse effects and drug resistance. METHODS: In this study, we compared the cytotoxic effect induced by TMZ and doxorubicin (DOXO), alone and in combination, on a low-grade astrocytoma cell line (AC1B) and a high-grade glioma cell line (GB1B). RESULTS: We found that TMZ and DOXO, each produced a cytotoxic effect in monotherapy. GB1B cell line was more sensitive to the treatment than AC1B cells, at a 7- and 10-day exposure to the DOXO. However, when the duration of the treatment was extended to 14 days, GB1B cells became more resistant to DOXO treatment, compared to AC1B cells. Regarding the treatment with TMZ, GB1B exhibited greater resistance to TMZ compared to AC1B, across all studied intervals and the resistance to treatment of GB1B increased with longer exposure time. However, in combined therapy, the drugs did not exert a synergistic effect on any astrocytic cell line. CONCLUSIONS: The current data suggest that both TMZ and DOXO exhibit efficient therapeutic effects on low- and high-grade glioma cells. However, no synergistic effect was observed for combined therapy.

Combined Statistical Analysis of Glioblastoma Outcomes-A Neurosurgical Single-Institution Retrospective Study.

Background and Objectives: Notwithstanding the major progress in the management of cancerous diseases in the last few decades, glioblastoma (GBM) remains the most aggressive brain malignancy, with a dismal prognosis, mainly due to treatment resistance and tumoral recurrence. In order to diagnose this disease and establish the optimal therapeutic approach to it, a standard tissue biopsy or a liquid biopsy can be performed, although the latter is currently less common. To date, both tissue and liquid biopsy have yielded numerous biomarkers that predict the evolution and response to treatment in GBM. However, despite all such efforts, GBM has the shortest recorded survival rates of all the primary brain malignancies. Materials and Methods: We retrospectively reviewed patients with a confirmed histopathological diagnosis of glioblastoma between June 2011 and June 2023. All the patients were treated in the Third Neurosurgical Department of the Clinical Emergency Hospital "Bagdasar-Arseni" in Bucharest, and their outcomes were analyzed and presented accordingly. Results: Out of 518 patients in our study, 222 (42.8%) were women and 296 (57.14%) were men. The most common clinical manifestations were headaches and limb paralysis, while the most frequent tumor locations were the frontal and temporal lobes. The survival rates were prolonged in patients younger than 60 years of age, in patients with gross total tumoral resection and less than 30% tumoral necrosis, as well as in those who underwent adjuvant radiotherapy. Conclusions: Despite significant advancements in relation to cancer diseases, GBM is still a field of great interest for research and in great need of new therapeutic approaches. Although the multimodal therapeutic approach can improve the prognosis, the survival rates are still short and the recurrences are constant.

A Synopsis of Biomarkers in Glioblastoma: Past and Present.

Accounting for 48% of malignant brain tumors in adults, glioblastoma has been of great interest in the last decades, especially in the biomolecular and neurosurgical fields, due to its incurable nature and notable neurological morbidity. The major advancements in neurosurgical technologies have positively influenced the extent of safe tumoral resection, while the latest progress in the biomolecular field of GBM has uncovered new potential therapeutical targets. Although GBM currently has no curative therapy, recent progress has been made in the management of this disease, both from surgical and molecular perspectives. The main current therapeutic approach is multimodal and consists of neurosurgical intervention, radiotherapy, and chemotherapy, mostly with temozolomide. Although most patients will develop treatment resistance and tumor recurrence after surgical removal, biomolecular advancements regarding GBM have contributed to a better understanding of this pathology and its therapeutic management. Over the past few decades, specific biomarkers have been discovered that have helped predict prognosis and treatment responses and contributed to improvements in survival rates.

A Neurosurgical Perspective on Brain Metastases from Renal Cell Carcinoma: Multi-Institutional, Retrospective Analysis.

BACKGROUND: While acknowledging the generally poor prognostic features of brain metastases from renal cell carcinoma (BM RCC), it is important to be aware of the fact that neurosurgery still plays a vital role in managing this disease, even though we have entered an era of targeted therapies. Notwithstanding their initial high effectiveness, these agents often fail, as tumors develop resistance or relapse. METHODS: The authors of this study aimed to evaluate patients presenting with BM RCC and their outcomes after being treated in the Neurosurgical Department of Clinical Emergency Hospital "Bagdasar-Arseni", and the Neurosurgical Department of the National Institute of Neurology and Neurovascular Diseases, Bucharest, Romania. The study is based on a thorough appraisal of the patient's demographic and clinicopathological data and is focused on the strategic role of neurosurgery in BM RCC. RESULTS: A total of 24 patients were identified with BM RCC, of whom 91.6% had clear-cell RCC (ccRCC) and 37.5% had a prior nephrectomy. Only 29.1% of patients harbored extracranial metastases, while 83.3% had a single BM RCC. A total of 29.1% of patients were given systemic therapy. Neurosurgical resection of the BM was performed in 23 out of 24 patients. Survival rates were prolonged in patients who underwent nephrectomy, in patients who received systemic therapy, and in patients with a single BM RCC. Furthermore, higher levels of hemoglobin were associated in our study with a higher number of BMs. CONCLUSION: Neurosurgery is still a cornerstone in the treatment of symptomatic BM RCC. Among the numerous advantages of neurosurgical intervention, the most important is represented by the quick reversal of neurological manifestations, which in most cases can be life-saving.

An Overview of Systemic Targeted Therapy in Renal Cell Carcinoma, with a Focus on Metastatic Renal Cell Carcinoma and Brain Metastases.

The most commonly diagnosed malignancy of the urinary system is represented by renal cell carcinoma. Various subvariants of RCC were described, with a clear-cell type prevailing in about 85% of all RCC tumors. Patients with metastases from renal cell carcinoma did not have many effective therapies until the end of the 1980s, as long as hormonal therapy and chemotherapy were the only options available. The outcomes were unsatisfactory due to the poor effectiveness of the available therapeutic options, but then interferon-alpha and interleukin-2 showed treatment effectiveness, providing benefits but only for less than half of the patients. However, it was not until 2004 that targeted therapies emerged, prolonging the survival rate. Currently, new technologies and strategies are being developed to improve the actual efficacy of available treatments and their prognostic aspects. This article summarizes the mechanisms of action, importance, benefits, adverse events of special interest, and efficacy of immunotherapy in metastatic renal cell carcinoma, with a focus on brain metastases.

An Overview of EGFR Mechanisms and Their Implications in Targeted Therapies for Glioblastoma.

Despite all of the progress in understanding its molecular biology and pathogenesis, glioblastoma (GBM) is one of the most aggressive types of cancers, and without an efficient treatment modality at the moment, it remains largely incurable. Nowadays, one of the most frequently studied molecules with important implications in the pathogenesis of the classical subtype of GBM is the epidermal growth factor receptor (EGFR). Although many clinical trials aiming to study EGFR targeted therapies have been performed, none of them have reported promising clinical results when used in glioma patients. The resistance of GBM to these therapies was proven to be both acquired and innate, and it seems to be influenced by a cumulus of factors such as ineffective blood-brain barrier penetration, mutations, heterogeneity and compensatory signaling pathways. Recently, it was shown that EGFR possesses kinase-independent (KID) pro-survival functions in cancer cells. It seems imperative to understand how the EGFR signaling pathways function and how they interconnect with other pathways. Furthermore, it is important to identify the mechanisms of drug resistance and to develop better tailored therapeutic agents.

The effect of Azo-dyes on glioblastoma cells in vitro.

Despite the multidisciplinary standard treatment of glioblastoma (GB) consisting of maximal surgical resection, followed by radiotherapy (RT) plus concomitant chemotherapy with temozolomide (TMZ), the majority of patients experience tumor progression and almost universal mortality. In recent years, efforts have been made to create new agents for GB treatment, of which azo-dyes proved to be potential candidates, showing antiproliferative effects by inducing apoptosis and by inhibiting different signaling pathways. In this study we evaluated the antiproliferative the effect of six azo-dyes and TMZ on a low passage human GB cell line using MTT assay. We found that all compounds proved antiproliferative properties on GB cells. At equimolar concentrations azo-dyes induced more cytotoxic effect than TMZ. We found that Methyl Orange required the lowest IC50 for 3 days of treatment (26.4684 µM), whilst for 7 days of treatment, two azo dyes proved to have the highest potency: Methyl Orange IC50 = 13.8808 µM and Sudan I IC50 = 12.4829 µM. The highest IC50 was determined for TMZ under both experimental situations. Conclusions: Our research represents a novelty, by offering unique valuable data regarding the azo-dye cyototoxic effects in high grade brain tumors. This study may focus the attention on azo-dye agents that may represent an insufficient exploited source of agents for cancer treatment.

Intracellular Pathways and Mechanisms of Colored Secondary Metabolites in Cancer Therapy.

Despite the great advancements made in cancer treatment, there are still many unsatisfied aspects, such as the wide palette of side effects and the drug resistance. There is an obvious increasing scientific attention towards nature and what it can offer the human race. Natural products can be used to treat many diseases, of which some plant products are currently used to treat cancer. Plants produce secondary metabolites for their signaling mechanisms and natural defense. A variety of plant-derived products have shown promising anticancer properties in vitro and in vivo. Rather than recreating the natural production environment, ongoing studies are currently setting various strategies to significantly manipulate the quantity of anticancer molecules in plants. This review focuses on the recently studied secondary metabolite agents that have shown promising anticancer activity, outlining their potential mechanisms of action and pathways.

Oncogenic Signalling of Growth Factor Receptors in Cancer: Mechanisms and Therapeutic Opportunities.

Cancer is a common name for several distinct diseases caused by uncontrolled cell growth and proliferation [...].

Glioblastoma Stem Cells-Useful Tools in the Battle against Cancer.

Glioblastoma stem cells (GSCs) are cells with a self-renewal ability and capacity to initiate tumors upon serial transplantation that have been linked to tumor cell heterogeneity. Most standard treatments fail to completely eradicate GSCs, causing the recurrence of the disease. GSCs could represent one reason for the low efficacy of cancer therapy and for the short relapse time. Nonetheless, experimental data suggest that the presence of therapy-resistant GSCs could explain tumor recurrence. Therefore, to effectively target GSCs, a comprehensive understanding of their biology and the survival and developing mechanisms during treatment is mandatory. This review provides an overview of the molecular features, microenvironment, detection, and targeting strategies of GSCs, an essential information required for an efficient therapy. Despite the outstanding results in oncology, researchers are still developing novel strategies, of which one could be targeting the GSCs present in the hypoxic regions and invasive edge of the glioblastoma.

Combined Effects of Doxorubicin and Temozolomide in Cultured Glioblastoma Cells.

The oncological field benefits of extensive medical research and various types of cancer notice improvements, however glioblastoma multiforme remains one of the deadliest cancers in humans with virtually no advance in survival and clinical outcome. Temozolomide, the FDA approved drug for glioblastoma, faces numerous challenges such as resistance and side effects. To overcome these challenges, many combination therapies are currently studied. The present study analyses the effects of temozolomide in combination with doxorubicin on a glioblastoma cell line. Our results showed that both drugs displayed a cytotoxic effect on the studied cells in single administration (55% for 100µM temozolomide at 14 days, 53% for 100µM doxorubicin at 14 days), but without a synergistic effect in dual therapy. Although the results failed to produce the expected effect, they propose new research perspectives in the future.

The Effect of Β-Arrestin2 Overexpression Regarding Viability and Temozolomide Treatment in High-Grade Glioma Cells.

The ß-arrestins (ß-arr) family are proteins that regulate the signaling and trafficking of various G protein-coupled receptors. Out of the four members, ß-arr 1 and 2 have been proven as essential actors behind different processes that lead to the progression of cancer as cell proliferation, migration, invasion and metastasis. In addition to this, these proteins are also capable of transmitting anti-apoptotic signals, influence tumor growth rate and drug resistance. Several studies have demonstrated that ß-arr 2 overexpression corelates with an impaired overall survival and also showed that it may mediate multidrug resistance in certain types of cancer. In the current study we analyzed the effect of ß-arr 2 overexpression on proliferation and how it affects Temozolomide (TMZ) response on the CL2:6 High Grade Glioma (HGG) cell line. We observed contradictory results after transfection, with ß-arr 2 overexpressing cells having a superior proliferation rate after 24 and 48h, when compared to untransfected cells, while the opposite was noted after 72h. In terms of response to TMZ, we observed a similar contradictory pattern with modest differences between doses being observed at 24h, while the smallest and largest doses in our experiment produced opposite effects after 48h and 72h. This further underscores the scarcity of information regarding the exact roles and the importance of ß-arrs in the intrinsic mechanisms which govern cancer cells.

Transcriptomic Crosstalk between Gliomas and Telencephalic Neural Stem and Progenitor Cells for Defining Heterogeneity and Targeted Signaling Pathways.

Recent studies have begun to reveal surprising levels of cell diversity in the human brain, both in adults and during development. Distinctive cellular phenotypes point to complex molecular profiles, cellular hierarchies and signaling pathways in neural stem cells, progenitor cells, neuronal and glial cells. Several recent reports have suggested that neural stem and progenitor cell types found in the developing and adult brain share several properties and phenotypes with cells from brain primary tumors, such as gliomas. This transcriptomic crosstalk may help us to better understand the cell hierarchies and signaling pathways in both gliomas and the normal brain, and, by clarifying the phenotypes of cells at the origin of the tumor, to therapeutically address their most relevant signaling pathways.

Glioblastoma pharmacotherapy: A multifaceted perspective of conventional and emerging treatments (Review).

Due to its localisation, rapid onset, high relapse rate and resistance to most currently available treatment methods, glioblastoma multiforme (GBM) is considered to be the deadliest type of all gliomas. Although surgical resection, chemotherapy and radiotherapy are among the therapeutic strategies used for the treatment of GBM, the survival rates achieved are not satisfactory, and there is an urgent need for novel effective therapeutic options. In addition to single-target therapy, multi-target therapies are currently under development. Furthermore, drugs are being optimised to improve their ability to cross the blood-brain barrier. In the present review, the main strategies applied for GBM treatment in terms of the most recent therapeutic agents and approaches that are currently under pre-clinical and clinical testing were discussed. In addition, the most recently reported experimental data following the testing of novel therapies, including stem cell therapy, immunotherapy, gene therapy, genomic correction and precision medicine, were reviewed, and their advantages and drawbacks were also summarised.

ELTD1-An Emerging Silent Actor in Cancer Drama Play.

The epidermal growth factor, latrophilin, and seven transmembrane domain-containing protein 1 (ELTD1), is a member of the G-protein coupled receptors (GPCRs) superfamily. Although discovered in 2001, ELTD1 has been investigated only by a few research groups, and important data about its role in normal and tumor cells is still missing. Even though its functions and structure are not yet fully understood, recent studies show that ELTD1 has a role in both physiological and pathological angiogenesis, and it appears to be a very important biomarker and a molecular target in cancer diseases. Upregulation of ELTD1 in malignant cells has been reported, and correlated with poor cancer prognosis. This review article aims to compile the existing data and to discuss the current knowledge on ELTD1 structure and signaling, and its role in physiological and neoplastic conditions.

The Interference between SARS-CoV-2 and Tyrosine Kinase Receptor Signaling in Cancer.

Cancer and viruses have a long history that has evolved over many decades. Much information about the interplay between viruses and cell proliferation and metabolism has come from the history of clinical cases of patients infected with virus-induced cancer. In addition, information from viruses used to treat some types of cancer is valuable. Now, since the global coronavirus pandemic erupted almost a year ago, the scientific community has invested countless time and resources to slow down the infection rate and diminish the number of casualties produced by this highly infectious pathogen. A large percentage of cancer cases diagnosed are strongly related to dysregulations of the tyrosine kinase receptor (TKR) family and its downstream signaling pathways. As such, many therapeutic agents have been developed to strategically target these structures in order to hinder certain mechanisms pertaining to the phenotypic characteristics of cancer cells such as division, invasion or metastatic potential. Interestingly, several authors have pointed out that a correlation between coronaviruses such as the SARS-CoV-1 and -2 or MERS viruses and dysregulations of signaling pathways activated by TKRs can be established. This information may help to accelerate the repurposing of clinically developed anti-TKR cancer drugs in COVID-19 management. Because the need for treatment is critical, drug repurposing may be an advantageous choice in the search for new and efficient therapeutic compounds. This approach would be advantageous from a financial point of view as well, given that the resources used for research and development would no longer be required and can be potentially redirected towards other key projects. This review aims to provide an overview of how SARS-CoV-2 interacts with different TKRs and their respective downstream signaling pathway and how several therapeutic agents targeted against these receptors can interfere with the viral infection. Additionally, this review aims to identify if SARS-CoV-2 can be repurposed to be a potential viral vector against different cancer types.

The Potential of Helianthin Loaded Into Magnetic Nanoparticles to Induce Cytotoxicity in Glioblastoma Cells.

The central nervous system tumors are the most common solid tumors in adults.. Unlike other types of cancers, brain cancer is much difficult to treat because of the blood-brain barrier (BBB) that prevents drug substances from crossing it and accessing the brain. Different types of methods to overcome BBB have been used in vivo and in vitro, of which the use of nanoparticle-mediated delivery of therapeutic drugs is particularly promising. In the present study, we used iron oxide magnetic nanoparticles (NPs) as carrier system for helianthin (He/NPs) to treat cancer cells derived from glioblastoma. An early passage cell cultures (GB1B), established in our laboratory from tissue obtained from a patient diagnosed with glioblastoma, was used. The cells were treated with different concentrations of NPs or HeNPs and then cell proliferation was measured at 24, 48 and 72 hours. Our results showed that the treatment with NPs was well tolerated by glioblastoma cells, the viability of the cells increased very slightly after the treatment. Furthermore, we demonstrated that helianthin loaded Fe3O4 magnetic nanoparticles induced cytotoxicity in human glioblastoma cells. The treatment with HeNPs induced dose and time dependent.

The effect of temozolomide in combination with doxorubicin in glioblastoma cells in vitro.

BACKGROUND: Prior to 2000, the DNA alkylating agents nitrosoureas were used as standard treatment of glioblastoma. Current treatments for glioblastoma patients consist of surgery followed by radiation in combination with temozolomide. Despite therapeutic advances, the prognosis for glioblastoma patients remains grim, with a five-year overall survival below 15%. In this study, our team analyzed the interaction between temozolomide and doxorubicin in a glioblastoma cell line, in vitro. MATERIALS AND METHOD: The cell line, established from a patient who underwent surgery at the "Bagdasar Arseni Emergency Hospital", was exposed to 10 µM and 100 µM of temozolomide and 10 nM and 100 nM of doxorubicin, respectively, over a period of 7, 10 and 14 days, in monotherapy and in combination. RESULTS: The results showed that both temozolomide (66.5% cytotoxicity for the 10 µM dose at 14 days) de and doxorubicin (66.8% cytotoxicity for the 10 nM dose after 14 days) were very effective in killing cancer cells in monotherapy, but failed to produce a synergistic effect when used in combination. CONCLUSION: While the results may be discouraging, they present an interesting prospect into how certain drug interactions can impact treatment response.

ß-arrestin 1 transfection induced cell death in high grade glioma in vitro.

The best known functions of ß-arrestins (ß-arr) are to regulate G protein-coupled receptors (GPCR) signaling through receptor desensitization and internalization. Many reports also suggest that ß-arrs play important role in immune regulation and inflammatory responses, under physiological and pathological conditions. Recent studies have shown that ß-arr 1 silencing halts proliferation and increases temozolomide (TMZ) response in glioblastoma (GBM) cells. The focus of this paper is to analyze the role of ß-arr 1 overexpression in the 18 high grade glioma (HGG) cell line in terms of viability and their response to TMZ treatment. For this reason, the cell line was transfected with ß-arr 1 and the effect was analyzed after 24 h, 48 h and 72 h in terms of proliferation and treatment response. We observed that ß-arr 1 overexpression induced a time and dose dependant inhibition in the HGG cells. Unexpectedly, ß-arr transfection resulted in a very mild increase in TMZ toxicity after 24 h, becoming non-statistically significant at 72 h. In conclusion, we showed that ß-arr 1 overexpression inhibits cell proliferation in the 18 cell line but only has a very modest effect on treatment response with the alkylating agent TMZ.