Glioblastoma stem cells are regulated by interleukin-8 signaling in a tumoral perivascular niche

Vascularised organoids: Recent advances and applications in cancer research

Organoids are three-dimensional (3D) cellular models designed to replicate human tissues and organs while preserving their physiological complexity and functionality. Among these, vascularised organoids represent a groundbreaking advancement in 3D tissue engineering, incorporating vascular networks into engineered tissues to more accurately mimic the in vivo tumour microenvironment. These models offer significantly improved physiological relevance compared to conventional two-dimensional cultures or animal models, positioning them as invaluable tools in cancer research. Despite their potential, the rapid proliferation of techniques and materials for developing vascularised organoids presents challenges for researchers navigating this dynamic field. This systematic review provides a comprehensive examination of methodologies for fabricating vascularised organoids, with a focus on strategies that enhance vascularisation and support organoid growth. It critically evaluates the materials used, emphasising those that effectively mimic the extracellular matrix and facilitate vascular network formation. Key advancements in engineered organoids models are highlighted, emphasising their potential for studying interactions between vasculature and cancer cells, conducting drug screening, and understanding cytokine regulation. In summary, this review provides an in-depth overview of the current landscape of vascularised organoid fabrication and functionality, addressing challenges and opportunities within the field. A detailed understanding of the scope and future trajectories is essential for advancing organoid development and expanding their applications in both basic cancer research and clinical practice. KEY POINTS: Comparative analysis: Evaluation of organoids, animal models, and 2D models, highlighting their respective strengths and limitations in replicating physiological conditions and studying disease processes. Vascularisation techniques: Comparative evaluation of vascularised organoid fabrication methods, emphasising their efficiency, scalability and ability to replicate physiological vascular networks. Material selection: Thorough evaluation of materials for vascularised organoid culture system, focusing on those that effectively mimic the extracellular matrix and support vascular network formation. Applications: Overview of organoid applications in basic cancer research and clinical settings, with an emphasis on their potential in drug discovery, disease modelling and exploring complex biological processes.

EZH2 functional dichotomy in reactive oxygen species-stratified glioblastoma

BACKGROUND

Enhancer of zeste homolog 2 (EZH2), well known for its canonical methyltransferase activity in transcriptional repression in many cancers including glioblastoma (GBM), has an understudied noncanonical function critical for sustained tumor growth. Recent GBM consortial efforts reveal complex molecular heterogeneity for which therapeutic vulnerabilities correlated with subtype stratification remain relatively unexplored. Current enzymatic EZH2 inhibitors (EZH2inh) targeting its canonical su(var)3-9, enhancer-of-zeste and trithorax domain show limited efficacy and lack durable response, suggesting that underlying differences in the noncanonical pathway may yield new knowledge. Here, we unveiled dual roles of the EZH2 CXC domain in therapeutically distinct, reactive oxygen species (ROS)-stratified tumors.

METHODS

We analyzed differentially expressed genes between ROS classes by examining cis-regulatory elements as well as clustering of activities and pathways to identify EZH2 as the key mediator in ROS-stratified cohorts. Pull-down assays and CRISPR knockout of EZH2 domains were used to dissect the distinct functions of EZH2 in ROS-stratified GBM cells. The efficacy of NF-κB-inducing kinase inhibitor (NIKinh) and standard-of-care temozolomide was evaluated using orthotopic patient-derived GBM xenografts.

RESULTS

In ROS(+) tumors, CXC-mediated co-interaction with RelB drives constitutive activation of noncanonical NF-κB2 signaling, sustaining the ROS(+) chemoresistant phenotype. In contrast, in ROS(-) subtypes, Polycomb Repressive Complex 2 methyltransferase activity represses canonical NF-κB. Addressing the lack of EZH2inh targeting its nonmethyltransferase roles, we utilized a brain-penetrant NIKinh that disrupts EZH2-RelB binding, consequently prolonging survival in orthotopic ROS(+)-implanted mice.

CONCLUSIONS

Our findings highlight the functional dichotomy of the EZH2 CXC domain in governing ROS-stratified therapeutic resistance, thereby advocating for the development of therapeutic approaches targeting its noncanonical activities and underscoring the significance of patient stratification methodologies.

Patient-based multilevel transcriptome exploration highlights relevant chemokines and chemokine receptor axes in glioblastoma

Chemokines and their receptors form a complex interaction network, crucial for precise leukocyte positioning and trafficking. In cancer, they promote malignant cell proliferation and survival but are also critical for immune cell infiltration in the tumor microenvironment. Glioblastoma (GBM) is the most common and lethal brain tumor, characterized by an immunosuppressive TME, with restricted immune cell infiltration. A better understanding of chemokine-receptor interactions is therefore essential for improving tumor immunogenicity. In this study, we assessed the expression of all human chemokines in adult-type diffuse gliomas, with particular focus on GBM, based on patient-derived samples. Publicly available bulk RNA sequencing datasets allowed us to identify the chemokines most abundantly expressed in GBM, with regard to disease severity and across different tumor subregions. To gain insight into the chemokines-receptor network at the single cell resolution, we explored GBmap, a curated resource integrating multiple scRNAseq datasets from different published studies. Our study constitutes the first patient-based handbook highlighting the relevant chemokine-receptor crosstalks, which are of significant interest in the perspective of a therapeutic modulation of the TME in GBM.

Targeting IL-8 and Its Receptors in Prostate Cancer: Inflammation, Stress Response, and Treatment Resistance

This review delves into the intricate roles of interleukin-8 (IL-8) and its receptors, CXCR1 and CXCR2, in prostate cancer (PCa), particularly in castration-resistant (CRPC) and metastatic CRPC (mCRPC). This review emphasizes the crucial role of the tumour microenvironment (TME) and inflammatory cytokines in promoting tumour progression and response to tumour cell targeting agents. IL-8, acting through C-X-C chemokine receptor type 1 (CXCR1) and type 2 (CXCR2), modulates multiple signalling pathways, enhancing the angiogenesis, proliferation, and migration of cancer cells. This review highlights the shift in PCa research focus from solely tumour cells to the non-cancer-cell components, including vascular endothelial cells, the extracellular matrix, immune cells, and the dynamic interactions within the TME. The immunosuppressive nature of the PCa TME significantly influences tumour progression and resistance to emerging therapies. Current treatment modalities, including androgen deprivation therapy and chemotherapeutics, encounter persistent resistance and are complicated by prostate cancer's notably "immune-cold" nature, which limits immune system response to the tumour. These challenges underscore the critical need for novel approaches that both overcome resistance and enhance immune engagement within the TME. The therapeutic potential of inhibiting IL-8 signalling is explored, with studies showing enhanced sensitivity of PCa cells to treatments, including radiation and androgen receptor inhibitors. Clinical trials, such as the ACE trial, demonstrate the efficacy of combining CXCR2 inhibitors with existing treatments, offering significant benefits, especially for patients with resistant PCa. This review also addresses the challenges in targeting cytokines and chemokines, noting the complexity of the TME and the need for precision in therapeutic targeting to avoid side effects and optimize outcomes.

Advancing precision medicine in gliomas through single-cell sequencing: unveiling the complex tumor microenvironment

Glioblastoma (GBM) displays an infiltrative growth characteristic that recruits neighboring normal cells to facilitate tumor growth, maintenance, and invasion into the brain. While the blood-brain barrier serves as a critical natural defense mechanism for the central nervous system, GBM disrupts this barrier, resulting in the infiltration of macrophages from the peripheral bone marrow and the activation of resident microglia. Recent advancements in single-cell transcriptomics and spatial transcriptomics have refined the categorization of cells within the tumor microenvironment for precise identification. The intricate interactions and influences on cell growth within the tumor microenvironment under multi-omics conditions are succinctly outlined. The factors and mechanisms involving microglia, macrophages, endothelial cells, and T cells that impact the growth of GBM are individually examined. The collaborative mechanisms of tumor cell-immune cell interactions within the tumor microenvironment synergistically promote the growth, infiltration, and metastasis of gliomas, while also influencing the immune status and therapeutic response of the tumor microenvironment. As immunotherapy continues to progress, targeting the cells within the inter-tumor microenvironment emerges as a promising novel therapeutic approach for GBM. By comprehensively understanding and intervening in the intricate cellular interactions within the tumor microenvironment, novel therapeutic modalities may be developed to enhance treatment outcomes for patients with GBM.

Directing B7-H3 chimeric antigen receptor T cell homing through IL-8 induces potent antitumor activity against pediatric sarcoma

BACKGROUND

Advances in pediatric oncology have occurred for some cancers; however, new therapies for sarcoma have been inadequate. Cellular immunotherapy using chimeric antigen receptor (CAR) T cells has shown dramatic benefits in leukemia, lymphoma, and multiple myeloma but has been far less successful in pediatric solid tumors such as rhabdomyosarcoma (RMS) and osteosarcoma (OS). Balancing issues of "on-target, off-tumor toxicity", investigators have identified B7-H3 as a broadly expressed tumor antigen with otherwise restricted expression on normal tissues. We hypothesized that rapid homing via a chemokine receptor and CAR engagement through B7-H3 would enhance CAR T cell efficacy in solid tumors.

METHODS

We generated B7-H3 CAR T cells that also express the Interleukin-8 (IL-8) receptor, CXCR2. Cytokine production, flow cytometry, Seahorse assays and RNA sequencing were used to compare the B7-H3 CXCR2 (BC2) CAR T cells with B7-H3 CAR T cells. We developed an IL-8 overexpressing human RMS mouse model to test homing and cytotoxicity in vivo.

RESULTS

We demonstrate that IL-8 is expressed by RMS and OS and expression significantly increases after radiation. Overexpression of an IL-8 receptor, CXCR2, on B7-H3 CAR T cells enhances homing into IL-8 expressing tumors, augments T cell metabolism and leads to significant tumor regression.

CONCLUSION

These findings warrant further investigation into the use of BC2 CAR T cells as a treatment for patients with RMS, OS and other B7-H3-expressing, IL-8 producing solid tumors.

Interleukin-8/CXCR1 Signaling Contributes to the Progression of Pulmonary Adenocarcinoma Resulting in Malignant Pleural Effusion

Pulmonary adenocarcinoma (PADC) treatment limited efficacy in preventing tumor progression, often resulting in malignant pleural effusion (MPE). MPE is filled with various mediators, especially interleukin-8 (IL-8). However, the role of IL-8 and its signaling mechanism within the fluid microenvironment (FME) implicated in tumor progression warrants further investigation. Primary cultured cells from samples of patients with MPE from PADC, along with a commonly utilized lung cancer cell line, were employed to examine the role of IL-8 and its receptor, CXCR1, through comparative analysis. Our study primarily assessed migration and invasion capabilities, epithelial-mesenchymal transition (EMT), and cancer stem cell (CSC) properties. Additionally, IL-8 levels in MPE fluid versus serum, along with immunohistochemical expression of IL-8/CXCR1 signaling in tumor tissue and cell blocks were analyzed. IL-8/CXCR1 overexpression enhanced EMT and CSC properties. Furthermore, the immunocytochemical examination of 17 cell blocks from patients with PADC and MPE corroborated the significant correlation between upregulated IL-8 and CXCR1 expression and the co-expression of IL-8 and CXCR1 in MPE with distant metastasis. In summary, the IL-8/ CXCR1 axis in FME is pivotal to tumor promotion via paracrine and autocrine signaling. Our study provides a therapeutic avenue for improving the prognosis of PADC patients with MPE.

Vasorin promotes endothelial differentiation of glioma stem cells via stimulating the transcription of VEGFR2

Gliomas are highly vascularized malignancies, but current anti-angiogenic treatments have not demonstrated practical improvements in patient survival. Studies have suggested that glioma-derived endothelial cell (GdEC) formed by glioma stem cell (GSC) differentiation may contribute to the failure of this treatment. However, the molecular mechanisms involved in GSC endothelial differentiation remain poorly understood. We previously reported that vasorin (VASN) is highly expressed in glioma and promotes angiogenesis. Here, we show that VASN expression positively correlates with GdEC signatures in glioma patients. VASN promotes the endothelial differentiation capacity of GSC in vitro and participates in the formation of GSC-derived vessels in vivo. Mechanistically, vascular endothelial growth factor receptor 2 (VEGFR2) is a critical factor that mediates the regulation of VASN on GSC endothelial differentiation. Separation of cell chromatin fractionation and chromatin immunoprecipitation-sequencing analysis show that VASN interacts with Notch1 and co-translocates into the cell nuclei, where VASN binds to the VEGFR2 gene promoter to stimulate its transcription during the progression of GSC differentiation into GdEC. Together, these findings elucidate the role and mechanisms of VASN in promoting the endothelial differentiation of GSC and suggest VASN as a potential target for anti-angiogenic therapy based on intervention in GdEC formation in gliomas.

IL-8 Instructs Macrophage Identity in Lateral Ventricle Contacting Glioblastoma

Adult IDH-wildtype glioblastoma (GBM) is a highly aggressive brain tumor with no established immunotherapy or targeted therapy. Recently, CD32+ HLA-DRhi macrophages were shown to have displaced resident microglia in GBM tumors that contact the lateral ventricle stem cell niche. Since these lateral ventricle contacting GBM tumors have especially poor outcomes, identifying the origin and role of these CD32+ macrophages is likely critical to developing successful GBM immunotherapies. Here, we identify these CD32+ cells as M_IL-8 macrophages and establish that IL-8 is sufficient and necessary for tumor cells to instruct healthy macrophages into CD32+ M_IL-8 M2 macrophages. In ex vivo experiments with conditioned medium from primary human tumor cells, inhibitory antibodies to IL-8 blocked the generation of CD32+ M_IL-8 cells. Finally, using a set of 73 GBM tumors, IL-8 protein is shown to be present in GBM tumor cells in vivo and especially common in tumors contacting the lateral ventricle. These results provide a mechanistic origin for CD32+ macrophages that predominate in the microenvironment of the most aggressive GBM tumors. IL-8 and CD32+ macrophages should now be explored as targets in combination with GBM immunotherapies, especially for patients whose tumors present with radiographic contact with the ventricular-subventricular zone stem cell niche.

Deciphering Glioblastoma: Fundamental and Novel Insights into the Biology and Therapeutic Strategies of Gliomas

Gliomas constitute a diverse and complex array of tumors within the central nervous system (CNS), characterized by a wide range of prognostic outcomes and responses to therapeutic interventions. This literature review endeavors to conduct a thorough investigation of gliomas, with a particular emphasis on glioblastoma (GBM), beginning with their classification and epidemiological characteristics, evaluating their relative importance within the CNS tumor spectrum. We examine the immunological context of gliomas, unveiling the intricate immune environment and its ramifications for disease progression and therapeutic strategies. Moreover, we accentuate critical developments in understanding tumor behavior, focusing on recent research breakthroughs in treatment responses and the elucidation of cellular signaling pathways. Analyzing the most novel transcriptomic studies, we investigate the variations in gene expression patterns in glioma cells, assessing the prognostic and therapeutic implications of these genetic alterations. Furthermore, the role of epigenetic modifications in the pathogenesis of gliomas is underscored, suggesting that such changes are fundamental to tumor evolution and possible therapeutic advancements. In the end, this comparative oncological analysis situates GBM within the wider context of neoplasms, delineating both distinct and shared characteristics with other types of tumors.

Intrinsic and Microenvironmental Drivers of Glioblastoma Invasion

Gliomas are diffusely infiltrating brain tumors whose prognosis is strongly influenced by their extent of invasion into the surrounding brain tissue. While lower-grade gliomas present more circumscribed borders, high-grade gliomas are aggressive tumors with widespread brain infiltration and dissemination. Glioblastoma (GBM) is known for its high invasiveness and association with poor prognosis. Its low survival rate is due to the certainty of its recurrence, caused by microscopic brain infiltration which makes surgical eradication unattainable. New insights into GBM biology at the single-cell level have enabled the identification of mechanisms exploited by glioma cells for brain invasion. In this review, we explore the current understanding of several molecular pathways and mechanisms used by tumor cells to invade normal brain tissue. We address the intrinsic biological drivers of tumor cell invasion, by tackling how tumor cells interact with each other and with the tumor microenvironment (TME). We focus on the recently discovered neuronal niche in the TME, including local as well as distant neurons, contributing to glioma growth and invasion. We then address the mechanisms of invasion promoted by astrocytes and immune cells. Finally, we review the current literature on the therapeutic targeting of the molecular mechanisms of invasion.

Huaier suppresses cisplatin resistance in non-small cell lung cancer by inhibiting the JNK/JUN/IL-8 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huaier (Trametes robiniophila Murr), a traditional Chinese medicinal fungus, possesses potent anticancer efficacy and has been used as an adjuvant medication for liver, breast, gastric, intestinal, and non-small cell lung cancer (NSCLC). However, the potential regulatory functions and underlying molecular mechanisms of Huaier in cisplatin resistance of NSCLC remain unknown.

AIM

To evaluate the potential regulatory functions and underlying molecular mechanisms of Huaier in cisplatin resistance of NSCLC.

MATERIALS AND METHODS

In vitro and in vivo experiments were employed to evaluate the regulatory functions of Huaier in cisplatin-resistant NSCLC cells. Transcriptome sequencing and validation analyses was undertaken to identify the downstream targets of Huaier. Network pharmacology, ultra-performance liquid chromatography-mass spectroscopy, and in vitro and in vivo experiments were performed to identify key small molecule drug candidates in Huaier and the regulatory mechanisms these employ to suppress cisplatin resistance in NSCLC.

RESULTS

Huaier suppressed cisplatin resistance and cancer cell stemness in cisplatin-resistant NSCLC cells, both in vitro and in vivo. Mechanistically, Huaier could suppress expression of interleuken-8 (IL-8) through inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activator protein-1 (AP-1), two key transcription factors responsible for the activation of IL-8 transcription. Kaempferol was identified as one of the key small molecule compounds in Huaier that could suppress cisplatin resistance by inhibiting the phosphorylation and nuclear translocation of proto-oncogene c-Jun (JUN) by binding and inhibiting the kinase activity of c-Jun N-terminal protein kinase (JNK).

CONCLUSIONS

Huaier suppressed cisplatin resistance of NSCLC cells by inhibiting the JNK/JUN/IL-8 signaling pathway.

The Inhibition of Vessel Co-Option as an Emerging Strategy for Cancer Therapy

Vessel co-option (VCO) is a non-angiogenic mechanism of vascularization that has been associated to anti-angiogenic therapy. In VCO, cancer cells hijack the pre-existing blood vessels and use them to obtain oxygen and nutrients and invade adjacent tissue. Multiple primary tumors and metastases undergo VCO in highly vascularized tissues such as the lungs, liver or brain. VCO has been associated with a worse prognosis. The cellular and molecular mechanisms that undergo VCO are poorly understood. Recent studies have demonstrated that co-opted vessels show a quiescent phenotype in contrast to angiogenic tumor blood vessels. On the other hand, it is believed that during VCO, cancer cells are adhered to basement membrane from pre-existing blood vessels by using integrins, show enhanced motility and a mesenchymal phenotype. Other components of the tumor microenvironment (TME) such as extracellular matrix, immune cells or extracellular vesicles play important roles in vessel co-option maintenance. There are no strategies to inhibit VCO, and thus, to eliminate resistance to anti-angiogenic therapy. This review summarizes all the molecular mechanisms involved in vessel co-option analyzing the possible therapeutic strategies to inhibit this process.

The origin of brain malignancies at the blood-brain barrier

Despite improvements in extracranial therapy, survival rate for patients suffering from brain metastases remains very poor. This is coupled with the incidence of brain metastases continuing to rise. In this review, we focus on core contributions of the blood-brain barrier to the origin of brain metastases. We first provide an overview of the structure and function of the blood-brain barrier under physiological conditions. Next, we discuss the emerging idea of a pre-metastatic niche, namely that secreted factors and extracellular vesicles from a primary tumor site are able to travel through the circulation and prime the neurovasculature for metastatic invasion. We then consider the neurotropic mechanisms that circulating tumor cells possess or develop that facilitate disruption of the blood-brain barrier and survival in the brain's parenchyma. Finally, we compare and contrast brain metastases at the blood-brain barrier to the primary brain tumor, glioma, examining the process of vessel co-option that favors the survival and outgrowth of brain malignancies.

Investigating Trans-differentiation of Glioblastoma Cells in an In Vitro 3D Model of the Perivascular Niche

Glioblastoma multiforme (GBM) is the deadliest form of brain cancer, responsible for over 50% of adult brain tumors. A specific region within the GBM environment is known as the perivascular niche (PVN). This area is defined as within approximately 100 μm of vasculature and plays an important role in the interactions between endothelial cells (ECs), astrocytes, GBM cells, and stem cells. We have designed a 3D in vitro model of the PVN comprising either collagen Type 1 or HyStem-C, human umbilical vein ECs (HUVECs), and LN229 (GBM) cells. HUVECs were encapsulated within the hydrogels to form vascular networks. After 7 days, LN229 cells were co-cultured to investigate changes in both cell types. Over a 14 day culture period, we measured alterations in HUVEC networks, the contraction of the hydrogels, trans-differentiation of LN229 cells, and the concentrations of two chemokines; CXCL12 and TGF-β. Increased cellular proliferation ranging from 10- to 16-fold was exhibited in co-cultures from days 8 to 14. This was accompanied with a decrease in the height of hydrogels of up to 68%. These changes in the biomaterial scaffold indicate that LN229-HUVEC interactions promote changes to the matrix. TGF-β and CXCL12 secretion increased approximately 2-2.6-fold each from day 8 to 14 in all co-cultures. The expression of CXCL12 correlated with cell colocalization, indicating a chemotactic role in enabling the migration of LN229 cells toward HUVECs in co-cultures. von Willebrand factor (vWF) was co-expressed with glial fibrillary acidic protein (GFAP) in up to 15% of LN229 cells after 24 h in co-culture. Additionally, when LN229 cells were co-cultured with human brain microvascular ECs, the percentages of GFAP⁺/vWF⁺ cells were up to 20% higher than that in co-cultures with HUVECs in collagen (2.2 mg/mL) and HyStem-C gels on day 14. The expression of vWF indicates the early stages of trans-differentiation of LN229 cells to an EC phenotype. Designing in vitro models of trans-differentiation may provide additional insights into how vasculature and cellular phenotypes are altered in GBM.

Dedifferentiated cells obtained from glioblastoma cell lines are an easy and robust model for mesenchymal glioblastoma stem cells studies

Glioblastoma is an aggressive brain tumor with a poor prognosis. Glioblastoma Stem Cells (GSC) are involved in glioblastoma resistance and relapse. Effective glioblastoma treatment must include GSC targeting strategy. Robust and well defined in vitroGSC models are required for new therapies evaluation. In this study, we extensively characterized 4 GSC models obtained by dedifferentiation of commercially available glioblastoma cell lines and compared them to 2 established patient derived GSC lines (Brain Tumor Initiating Cells). Dedifferentiated cells formed gliospheres, typical for GSC, with self-renewal ability. Gene expression and protein analysis revealed an increased expression of several stemness associated markers such as A2B5, integrin α6, Nestin, SOX2 and NANOG. Cells were oriented toward a mesenchymal GSC phenotype as shown by elevated levels of mesenchymal and EMT related markers (CD44, FN1, integrin α5). Dedifferentiated GSC were similar to BTIC in terms of size and heterogeneity. The characterization study also revealed that CXCR4 pathway was activated by dedifferentiation, emphasizing its role as a potential therapeutic target. The expression of resistance-associated markers and the phenotypic diversity of the 4 GSC models obtained by dedifferentiation make them relevant to challenge future GSC targeting therapies.

Shaping the brain vasculature in development and disease in the single-cell era

The CNS critically relies on the formation and proper function of its vasculature during development, adult homeostasis and disease. Angiogenesis - the formation of new blood vessels - is highly active during brain development, enters almost complete quiescence in the healthy adult brain and is reactivated in vascular-dependent brain pathologies such as brain vascular malformations and brain tumours. Despite major advances in the understanding of the cellular and molecular mechanisms driving angiogenesis in peripheral tissues, developmental signalling pathways orchestrating angiogenic processes in the healthy and the diseased CNS remain incompletely understood. Molecular signalling pathways of the 'neurovascular link' defining common mechanisms of nerve and vessel wiring have emerged as crucial regulators of peripheral vascular growth, but their relevance for angiogenesis in brain development and disease remains largely unexplored. Here we review the current knowledge of general and CNS-specific mechanisms of angiogenesis during brain development and in brain vascular malformations and brain tumours, including how key molecular signalling pathways are reactivated in vascular-dependent diseases. We also discuss how these topics can be studied in the single-cell multi-omics era.

Human Forebrain Organoid-Derived Extracellular Vesicle Labeling with Iron Oxides for In Vitro Magnetic Resonance Imaging

The significant roles of extracellular vesicles (EVs) as intracellular mediators, disease biomarkers, and therapeutic agents, make them a scientific hotspot. In particular, EVs secreted by human stem cells show significance in treating neurological disorders, such as Alzheimer’s disease and ischemic stroke. However, the clinical applications of EVs are limited due to their poor targeting capabilities and low therapeutic efficacies after intravenous administration. Superparamagnetic iron oxide (SPIO) nanoparticles are biocompatible and have been shown to improve the targeting ability of EVs. In particular, ultrasmall SPIO (USPIO, <50 nm) are more suitable for labeling nanoscale EVs due to their small size. In this study, induced forebrain neural progenitor cortical organoids (iNPCo) were differentiated from human induced pluripotent stem cells (iPSCs), and the iNPCo expressed FOXG1, Nkx2.1, α-catenin, as well as β-tubulin III. EVs were isolated from iNPCo media, then loaded with USPIOs by sonication. Size and concentration of EV particles were measured by nanoparticle tracking analysis, and no significant changes were observed in size distribution before and after sonication, but the concentration decreased after labeling. miR-21 and miR-133b decreased after sonication. Magnetic resonance imaging (MRI) demonstrated contrast visualized for the USPIO labeled EVs embedded in agarose gel phantoms. Upon calculation, USPIO labeled EVs exhibited considerably shorter relaxation times, quantified as T2 and T2* values, reducing the signal intensity and generating higher MRI contrast compared to unlabeled EVs and gel only. Our study demonstrated that USPIO labeling was a feasible approach for in vitro tracking of brain organoid-derived EVs, which paves the way for further in vivo examination.

Perivascular Stromal Cells Instruct Glioblastoma Invasion, Proliferation, and Therapeutic Response within an Engineered Brain Perivascular Niche Model

Glioblastoma (GBM) tumor cells are found in the perivascular niche microenvironment and are believed to associate closely with the brain microvasculature. However, it is largely unknown how the resident cells of the perivascular niche, such as endothelial cells, pericytes, and astrocytes, influence GBM tumor cell behavior and disease progression. A 3D in vitro model of the brain perivascular niche developed by encapsulating brain-derived endothelial cells, pericytes, and astrocytes in a gelatin hydrogel is described. It is shown that brain perivascular stromal cells, namely pericytes and astrocytes, contribute to vascular architecture and maturation. Cocultures of patient-derived GBM tumor cells with brain microvascular cells are used to identify a role for pericytes and astrocytes in establishing a perivascular niche environment that modulates GBM cell invasion, proliferation, and therapeutic response. Engineered models provide unique insight regarding the spatial patterning of GBM cell phenotypes in response to a multicellular model of the perivascular niche. Critically, it is shown that engineered perivascular models provide an important resource to evaluate mechanisms by which intercellular interactions modulate GBM tumor cell behavior, drug response, and provide a framework to consider patient-specific disease phenotypes.

PDCD10 promotes the aggressive behaviors of pituitary adenomas by up-regulating CXCR2 and activating downstream AKT/ERK signaling

As the second most common primary intracranial neoplasms, about 40% of pituitary adenomas (PAs) exhibit aggressive behaviors and resulting in poor patient prognosis. The molecular mechanisms underlying the aggressive behaviors of PAs are not yet fully understood. Biochemical studies have reported that programmed cell death 10 (PDCD10) is a component of the striatin-interacting phosphatase and kinase (STRIPAK) complex and plays a dual role in cancers in a tissue- or disease-specific manner. In the present study, we report for the first time that the role of PDCD10 in PAs. Cell proliferation, migration and invasion were either enhanced by overexpressing or inhibited by silencing PDCD10 in PA cells. Moreover, PDCD10 significantly promoted epithelial–mesenchymal transition (EMT) of pituitary adenoma cells. Mechanistically, we showed that the expression of CXCR2, together with phosphorylation levels of AKT and ERK1/2 were regulated by PDCD10. Activation of CXCR2 inversed inactivation of AKT/ERK signal pathways and the tumor-suppressive effects induced by PDCD10 silencing. Finally, the pro-oncogenic effect of PDCD10 was confirmed by in vivo tumor grafting. Taken together, we demonstrate for the first time that PDCD10 can induce aggressive behaviors of PAs by promoting cellular proliferation, migration, invasion and EMT through CXCR2-AKT/ERK signaling axis.

Dynamic Interactions between Tumor Cells and Brain Microvascular Endothelial Cells in Glioblastoma

GBM is the most aggressive brain tumor among adults. It is characterized by extensive vascularization, and its further growth and recurrence depend on the formation of new blood vessels. In GBM, tumor angiogenesis is a multi-step process involving the proliferation, migration and differentiation of BMECs under the stimulation of specific signals derived from the cancer cells through a wide variety of communication routes. In this review, we discuss the dynamic interaction between BMECs and tumor cells by providing evidence of how tumor cells hijack the BMECs for the formation of new vessels. Tumor cell-BMECs interplay involves multiple routes of communication, including soluble factors, such as chemokines and cytokines, direct cell-cell contact and extracellular vesicles that participate in and fuel this cooperation. We also describe how this interaction is able to modify the BMECs structure, metabolism and physiology in a way that favors tumor growth and invasiveness. Finally, we briefly reviewed the recent advances and the potential future implications of some high-throughput 3D models to better understanding the complexity of BMECs-tumor cell interaction.

The Role and Mechanism of the Vascular Endothelial Niche in Diseases: A Review

Vascular endothelial cells, forming the inner wall of the blood vessels, participate in the body’s pathological and physiological processes of immunity, tumors, and infection. In response to an external stimulus or internal pathological changes, vascular endothelial cells can reshape their microenvironment, forming a “niche”. Current research on the vascular endothelial niche is a rapidly growing field in vascular biology. Endothelial niches not only respond to stimulation by external information but are also decisive factors that act on neighboring tissues and circulating cells. Intervention through the vascular niche is meaningful for improving the treatment of several diseases. This review aimed to summarize reported diseases affected by endothelial niches and signal molecular alterations or release within endothelial niches. We look forward to contributing knowledge to increase the understanding the signaling and mechanisms of the vascular endothelial niche in multiple diseases.

CXCR2 Small-Molecule Antagonist Combats Chemoresistance and Enhances Immunotherapy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer as the absence of cell surface receptors renders it more difficult to be therapeutically targeted. Chemokine receptor 2 (CXCR2) has been suggested not only to promote therapy resistance and suppress immunotherapy but it also to possess a positive cross-talk with the multifunctional cytokine transforming growth factor beta (TGF-β). Here, we showed that CXCR2 and TGF-β signaling were both upregulated in human TNBC biopsies. CXCR2 inhibition abrogated doxorubicin-mediated TGF-β upregulation in 3D in vitro TNBC coculture with PBMCs and eliminated drug resistance in TNBC mammospheres, suggesting a vital role for CXCR2 in TNBC doxorubicin-resistance via TGF-β signaling regulation. Moreover, CXCR2 inhibition improved the efficacy of the immunotherapeutic drug "atezolizumab" where the combined inhibition of CXCR2 and PDL1 in TNBC in vitro coculture showed an additive effect in cytotoxicity. Altogether, the current study suggests CXCR2 inhibitors as a promising approach to improve TNBC treatment if used in combination with chemotherapy and/or immunotherapy.

Investigating Cancerous Exosomes’ Effects on CD8+ T-Cell IL-2 Production in a 3D Unidirectional Flow Bioreactor Using 3D Printed, RGD-Functionalized PLLA Scaffolds

Exosomes from cancer cells are implicated in cancer progression and metastasis, carrying immunosuppressive factors that limit the antitumor abilities of immune cells. The development of a real-time, 3D cell/scaffold construct flow perfusion system has been explored as a novel tool in the study of T-cells and exosomes from cancer cells. Exosomes from human lung cancer (H1299 and A549) cells were co-cultured in a unidirectional flow bioreactor with CD8+ T-cells immobilized onto 3D-printed RGD-functionalized poly(L-lactic) acid (PLLA) scaffolds and assessed for IL-2 production. The IL-2 production was investigated for a wide range of T-cell to exosome ratios. With the successful incorporation of the RGD binding motif onto the PLLA surface at controllable densities, CD8+ T-cells were successfully attached onto 2D disks and 3D printed porous PLLA scaffolds. T-cell attachment increased with increasing RGD surface density. The diameter of the attached T-cells was 7.2 ± 0.2 µm for RGD densities below 0.5 nmoles/mm2 but dropped to 5.1 ± 0.3 µm when the RGD density was 2 nmoles/mm2 due to overcrowding. The higher the number of cancer exosomes, the less the IL-2 production by the surface-attached T-cells. In 2D disks, the IL-2 production was silenced for T-cell to exosome ratios higher than 1:10 in static conditions. IL-2 production silencing in static 3D porous scaffolds required ratios higher than 1:20. The incorporation of flow resulted in moderate to significant T-cell detachment. The portions of T-cells retained on the 3D scaffolds after exposure for 4 h to 0.15 or 1.5 mL/min of perfusion flow were 89 ± 11% and 30 ± 8%, respectively. On 3D scaffolds and in the presence of flow at 0.15 ml/min, both H1299 and A549 cancerous exosomes significantly suppressed IL-2 production for T-cell to exosome ratios of 1:1000. The much higher level of exosomes needed to silence the IL-2 production from T-cells cultured under unidirectional flow, compared to static conditions, denotes the importance of the culturing conditions and the hydrodynamic environment, on the interactions between CD8+ T-cells and cancer exosomes.

The Subventricular Zone in Glioblastoma: Genesis, Maintenance, and Modeling

Glioblastoma (GBM) is a malignant tumor with a median survival rate of 15-16 months with standard care; however, cases of successful treatment offer hope that an enhanced understanding of the pathology will improve the prognosis. The cell of origin in GBM remains controversial. Recent evidence has implicated stem cells as cells of origin in many cancers. Neural stem/precursor cells (NSCs) are being evaluated as potential initiators of GBM tumorigenesis. The NSCs in the subventricular zone (SVZ) have demonstrated similar molecular profiles and share several distinctive characteristics to proliferative glioblastoma stem cells (GSCs) in GBM. Genomic and proteomic studies comparing the SVZ and GBM support the hypothesis that the tumor cells and SVZ cells are related. Animal models corroborate this connection, demonstrating migratory patterns from the SVZ to the tumor. Along with laboratory and animal research, clinical studies have demonstrated improved progression-free survival in patients with GBM after radiation to the ipsilateral SVZ. Additionally, key genetic mutations in GBM for the most part carry regulatory roles in the SVZ as well. An exciting avenue towards SVZ modeling and determining its role in gliomagenesis in the human context is human brain organoids. Here we comprehensively discuss and review the role of the SVZ in GBM genesis, maintenance, and modeling.

Enhanced expression of pentraxin-3 in glioblastoma cells correlates with increased invasion and IL8-VEGF signaling axis

Glioblastoma (GB) is highly invasive and resistant to multimodal treatment partly due to distorted vasculature and exacerbated inflammation. The aggressiveness of brain tumors may be attributed to the dysregulated release of angiogenic and inflammatory factors. The glycoprotein pentraxin-3 (PTX3) is correlated with the severity of some cancers. However, the mechanism responsible for the invasive oncogenic role of PTX3 in GB malignancy remains unclear. In this study, we examined the role of PTX3 in GB growth, angiogenesis, and invasion using in vitro and in vivo GB models, proteomic profiling, molecular and biochemical approaches. Under in vitro conditions, PTX3 over-expression in U87 cells correlated with cell cycle progression, increased migratory potential, and proliferation under hypoxic conditions. Conditioned media containing PTX3 enhanced the angiogenic potential of endothelial cells. While silencing of PTX3 by siRNA decreased the proliferation, migration, and angiogenic potential of U87 cells in vitro. Importantly, PTX3 over-expression increased tumor growth, angiogenesis, and invasion in an orthotopic mouse model. Higher levels of PTX3 in these tumors were associated with the upregulation of inflammatory and angiogenic markers including interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF), but decreased levels of thrombospondin-1, an anti-angiogenic factor. Mechanistically, exogenous production of PTX3 triggered an IKK/NFκB signaling pathway that enhances the expression of the motility genes AHGEF7 and Rac1. Taken together, PTX3 expression is dysregulated in GB. PTX3 may augment invasion through enhanced angiogenesis in the GB microenvironment through the IL8-VEGF axis. Thus, PTX3 may represent a potential therapeutic target to mitigate the aggressive behavior of gliomas.

The microenvironment of brain metastases from solid tumors

Brain metastasis (BrM) is an area of unmet medical need that poses unique therapeutic challenges and heralds a dismal prognosis. The intracranial tumor microenvironment (TME) presents several challenges, including the therapy-resistant blood-brain barrier, a unique immune milieu, distinct intercellular interactions, and specific metabolic conditions, that are responsible for treatment failures and poor clinical outcomes. There is a complex interplay between malignant cells that metastasize to the central nervous system (CNS) and the native TME. Cancer cells take advantage of vascular, neuronal, immune, and anatomical vulnerabilities to proliferate with mechanisms specific to the CNS. In this review, we discuss unique aspects of the TME in the context of brain metastases and pathways through which the TME may hold the key to the discovery of new and effective therapies for patients with BrM.

Modulation of the blood-tumor barrier to enhance drug delivery and efficacy for brain metastases

The blood-brain barrier is the selectively permeable vasculature of the brain vital for maintaining homeostasis and neurological function. Low permeability is beneficial in the presence of toxins and pathogens in the blood. However, in the presence of metastatic brain tumors, it is a challenge for drug delivery. Although the blood-tumor barrier is slightly leaky, it still is not permissive enough to allow the accumulation of therapeutic drug concentrations in brain metastases. Herein, we discuss the differences between primary brain tumors and metastatic brain tumors vasculature, effects of therapeutics on the blood-tumor barrier, and characteristics to be manipulated for more effective drug delivery.

Stem Cells and Cancer Stem Cells: The Jekyll and Hyde Scenario and Their Implications in Stem Cell Therapy

"Jekyll and Hyde" refers to persons with an unpredictably dual personality, who are battling between good and evil within themselves In this regard, even cells consist of good and evil counterparts. Normal stem cells (NSCs) and cancer stem cells (CSCs) are two types of cells that share some similar characteristics but have distinct functions that play a major role in physiological and pathophysiological development. In reality, NSCs such as the adult and embryonic stem cells, are the good cells and the ultimate treatment used in cell therapy. CSCs are the corrupted cells that are a subpopulation of cancer cells within the cancer microenvironment that grow into a massive tumour or malignancy that needs to be treated. Hence, understanding the connection between NSCs and CSCs is important not just in cancer development but also in their therapeutic implication, which is the focus of this review.

Environmental interplay: Stromal cells and biomaterial composition influence in the glioblastoma microenvironment

Glioblastoma multiforme (GBM) is the most deadly form of brain cancer. Recurrence is common, and established therapies have not been able to significantly extend overall patient survival. One platform through which GBM research can progress is to design biomimetic systems for discovery and investigation into the mechanisms of invasion, cellular properties, as well as the efficacy of therapies. In this review, 2D and 3D GBM in vitro cultures will be discussed. We focus on the effects of biomaterial properties, interactions between stromal cells, and vascular influence on cancer cell survival and progression. This review will summarize critical findings in each of these areas and how they have led to a more comprehensive scientific understanding of GBM. STATEMENT OF SIGNIFICANCE: Glioblastoma multiforme (GBM) is the most deadly form of brain cancer. Recurrence is common, and established therapies have not been able to significantly extend overall patient survival. One platform through which GBM research can progress is to design biomimetic systems for discovery and investigation into the mechanisms of invasion, cellular properties, as well as the efficacy of therapies. In this review, 2D and 3D GBM in vitro cultures will be discussed. We focus on the effects of biomaterial properties, interactions between stromal cells and vascular influence on cancer cell survival and progression. This review will summarize critical findings in each of these areas and how they have lead to a more comprehensive scientific understanding of GBM.

DNAM-1/CD226 is functionally expressed on acute myeloid leukemia (AML) cells and is associated with favorable prognosis

DNAM-1 is reportedly expressed on cytotoxic T and NK cells and, upon interaction with its ligands CD112 and CD155, plays an important role in tumor immunosurveillance. It has also been reported to be functionally expressed by myeloid cells, but expression and function on malignant cells of the myeloid lineage have not been studied so far. Here we analyzed expression of DNAM-1 in leukemic cells of acute myeloid leukemia (AML) patients. We found substantial levels of DNAM-1 to be expressed on leukemic blasts in 48 of 62 (> 75%) patients. Interaction of DNAM-1 with its ligands CD112 and CD155 induced release of the immunomodulatory cytokines IL-6, IL-8 IL-10 and TNF-α by AML cells and DNAM-1 expression correlated with a more differentiated phenotype. Multivariate analysis did not show any association of DNAM-1 positivity with established risk factors, but expression was significantly associated with clinical disease course: patients with high DNAM-1 surface levels had significantly longer progression-free and overall survival compared to DNAM-1^low patients, independently whether patients had undergone allogenic stem cell transplantation or not. Together, our findings unravel a functional role of DNAM-1 in AML pathophysiology and identify DNAM-1 as a potential novel prognostic maker in AML.

Engineering strategies to capture the biological and biophysical tumor microenvironment in vitro

Despite decades of research and advancements in diagnostic and treatment modalities, cancer remains a major global healthcare challenge. This is due in part to a lack of model systems that allow investigating the mechanisms underlying tumor development, progression, and therapy resistance under relevant conditions in vitro. Tumor cell interactions with their surroundings influence all stages of tumorigenesis and are shaped by both biological and biophysical cues including cell-cell and cell-extracellular matrix (ECM) interactions, tissue architecture and mechanics, and mass transport. Engineered tumor models provide promising platforms to elucidate the individual and combined contributions of these cues to tumor malignancy under controlled and physiologically relevant conditions. This review will summarize current knowledge of the biological and biophysical microenvironmental cues that influence tumor development and progression, present examples of in vitro model systems that are presently used to study these interactions and highlight advancements in tumor engineering approaches to further improve these technologies.

Peripheral Blood-Based Biomarkers for Immune Checkpoint Inhibitors

As cancer immunotherapy using immune checkpoint inhibitors (ICIs) is rapidly evolving in clinical practice, it is necessary to identify biomarkers that will allow the selection of cancer patients who will benefit most or least from ICIs and to longitudinally monitor patients' immune responses during treatment. Various peripheral blood-based immune biomarkers are being identified with recent advances in high-throughput multiplexed analytical technologies. The identification of these biomarkers, which can be easily detected in blood samples using non-invasive and repeatable methods, will contribute to overcoming the limitations of previously used tissue-based biomarkers. Here, we discuss the potential of circulating immune cells, soluble immune and inflammatory molecules, circulating tumor cells and DNA, exosomes, and the blood-based tumor mutational burden, as biomarkers for the prediction of immune responses and clinical benefit from ICI treatment in patients with advanced cancer.

Multidimensional hydrogel models reveal endothelial network angiocrine signals increase glioblastoma cell number, invasion, and temozolomide resistance

Glioblastoma (GBM) is the most common primary malignant brain tumor. The tissue microenvironment adjacent to vasculature, termed the perivascular niche, has been implicated in promoting biological processes involved in glioblastoma progression such as invasion, proliferation, and therapeutic resistance. However, the exact nature of the cues that support tumor cell aggression in this niche is largely unknown. Soluble angiocrine factors secreted by tumor-associated vasculature have been shown to support such behaviors in other cancer types. Here, we exploit macroscopic and microfluidic gelatin hydrogel platforms to profile angiocrine factors secreted by self-assembled endothelial networks and evaluate their relevance to glioblastoma biology. Aggregate angiocrine factors support increases in U87-MG cell number, migration, and therapeutic resistance to temozolomide. We also identify a novel role for TIMP1 in facilitating glioblastoma tumor cell migration. Overall, this work highlights the use of multidimensional hydrogel models to evaluate the role of angiocrine signals in glioblastoma progression.

Hydrogel-Based Spheroid Models of Glioblastoma for Drug Screening Applications

Glioblastoma multiforme (GBM) is the most aggressive brain tumor, with median patient survival of 12-15 months even after treatment. To facilitate basic research as well as treatment development, bioengineered GBM models that adequately recapitulate aspects of the in vivo tumor microenvironment are greatly needed. Multicellular spheroids are a well-accepted model in tumor biology as well as drug screening because they recapitulate many of the solid tumor characteristics, such as hypoxic core and cell-cell communication. There are multiple approaches for growing GBM cells into tumor spheroids - non-adherent plastic dishes, hanging drop, bioreactors, and hydrogels, amongst others. Suspension spheroid models offer ease of growth, uniformity, and overall lower cost, but neglect the cell-matrix interactions, while hydrogel-based spheroids capture cell-matrix interactions and allow co-cultures with stromal cells. In this review, we summarize various approaches to fabricate GBM spheroid models as well as GBM spheroid characteristics and chemotherapeutic responsiveness as a function of hydrogel matrix encapsulation and properties, in order to advance therapies.

Inhibition of CXCR2 plays a pivotal role in re-sensitizing ovarian cancer to cisplatin treatment

cDNA microarray data conducted by our group revealed overexpression of CXCL2 and CXCL8 in ovarian cancer (OC) microenvironment. Herein, we have proven that the chemokine receptor, CXCR2, is a pivotal molecule in re-sensitizing OC to cisplatin, and its inhibition decreases cell proliferation, viability, tumor size in cisplatin-resistant cells, as well as reversed the overexpression of mesenchymal epithelium transition markers. Altogether, our study indicates a central effect of CXCR2 in preventing tumor progression, due to acquisition of cisplatin chemoresistant phenotype by tumor cells, and patients' high lethality rate. We found that the overexpression of CXCR2 by OC cells is persistent and anomalously confined to the cellular nuclei, thus pointing to an urge in developing highly lipophilic molecules that promptly permeate cells, bind to and inhibit nuclear CXCR2 to fight OC, instead of relying on the high-cost genetic engineered cells.

Residual Disease in Glioma Recurrence: A Dangerous Liaison with Senescence

With a dismally low median survival of less than two years after diagnosis, Glioblastoma (GBM) is the most lethal type of brain cancer. The standard-of-care of surgical resection, followed by DNA-damaging chemo-/radiotherapy, is often non-curative. In part, this is because individual cells close to the resection border remain alive and eventually undergo renewed proliferation. These residual, therapy-resistant cells lead to rapid recurrence, against which no effective treatment exists to date. Thus, new experimental approaches need to be developed against residual disease to prevent GBM survival and recurrence. Cellular senescence is an attractive area for the development of such new approaches. Senescence can occur in healthy cells when they are irreparably damaged. Senescent cells develop a chronic secretory phenotype that is generally considered pro-tumorigenic and pro-migratory. Age is a negative prognostic factor for GBM stage, and, with age, senescence steadily increases. Moreover, chemo-/radiotherapy can provide an additional increase in senescence close to the tumor. In light of this, we will review the importance of senescence in the tumor-supportive brain parenchyma, focusing on the invasion and growth of GBM in residual disease. We will propose a future direction on the application of anti-senescence therapies against recurrent GBM.

Macrophages and microglia: the cerberus of glioblastoma

Glioblastoma (GBM) is the most aggressive and deadliest of the primary brain tumors, characterized by malignant growth, invasion into the brain parenchyma, and resistance to therapy. GBM is a heterogeneous disease characterized by high degrees of both inter- and intra-tumor heterogeneity. Another layer of complexity arises from the unique brain microenvironment in which GBM develops and grows. The GBM microenvironment consists of neoplastic and non-neoplastic cells. The most abundant non-neoplastic cells are those of the innate immune system, called tumor-associated macrophages (TAMs). TAMs constitute up to 40% of the tumor mass and consist of both brain-resident microglia and bone marrow-derived myeloid cells from the periphery. Although genetically stable, TAMs can change their expression profiles based upon the signals that they receive from tumor cells; therefore, heterogeneity in GBM creates heterogeneity in TAMs. By interacting with tumor cells and with the other non-neoplastic cells in the tumor microenvironment, TAMs promote tumor progression. Here, we review the origin, heterogeneity, and functional roles of TAMs. In addition, we discuss the prospects of therapeutically targeting TAMs alone or in combination with standard or newly-emerging GBM targeting therapies.

Identification of Hub Genes and Key Pathways Associated with Anti-VEGF Resistant Glioblastoma Using Gene Expression Data Analysis

Anti-VEGF therapy is considered to be a useful therapeutic approach in many tumors, but the low efficacy and drug resistance limit its therapeutic potential and promote tumor growth through alternative mechanisms. We reanalyzed the gene expression data of xenografts of tumors of bevacizumab-resistant glioblastoma multiforme (GBM) patients, using bioinformatics tools, to understand the molecular mechanisms of this resistance. An analysis of the gene set data from three generations of xenografts, identified as 646, 873 and 1220, differentially expressed genes (DEGs) in the first, fourth and ninth generations, respectively, of the anti-VEGF-resistant GBM cells. Gene Ontology (GO) and pathway enrichment analyses demonstrated that the DEGs were significantly enriched in biological processes such as angiogenesis, cell proliferation, cell migration, and apoptosis. The protein–protein interaction network and module analysis revealed 21 hub genes, which were enriched in cancer pathways, the cell cycle, the HIF1 signaling pathway, and microRNAs in cancer. The VEGF pathway analysis revealed nine upregulated (IL6, EGFR, VEGFA, SRC, CXCL8, PTGS2, IDH1, APP, and SQSTM1) and five downregulated hub genes (POLR2H, RPS3, UBA52, CCNB1, and UBE2C) linked with several of the VEGF signaling pathway components. The survival analysis showed that three upregulated hub genes (CXCL8, VEGFA, and IDH1) were associated with poor survival. The results predict that these hub genes associated with the GBM resistance to bevacizumab may be potential therapeutic targets or can be biomarkers of the anti-VEGF resistance of GBM.

A vasculature-centric approach to developing novel treatment options for glioblastoma

Introduction: Glioblastoma is invariably deadly and is characterized by extensive vascularization and macrophage-dominant immunosuppression; nevertheless, anti-angiogenesis has so far failed to prolong overall survival of patients. Regardless of the problems in clinical development, the rationale for the application of anti-angiogenics in glioblastoma remains.Areas covered: Resistance to anti-angiogenics is discussed, including vessel co-option and amplification of hypoxic signaling in response to vessel destruction. The modulation of GSC and tumor-associated macrophages by dysfunctional tumor vessels and by hypoxia are outlined. Pharmacologic approaches to sensitizing glioblastomas to anti-angiogenics and evidence for the cooperation of anti-angiogenics with immunotherapies are summarized. Database search: https://pubmed.ncbi.nlm.nih.gov prior to December 12, 2020.Expert opinion: Despite drawbacks in the clinical development of vascular endothelial growth factor A (VEGF)-targeted agents, there is still rationale for the use of anti-angiogenics. The better understanding of vascular co-option and adverse effects of blood vessel destruction guides to improve strategies for vascular targeting. The pivotal role of the vasculature and of angiogenic factors such as VEGF for the induction and maintenance of immunosuppression in glioblastoma supports the use of anti-angiogenics in combination with immunotherapy. Proinflammatory repolarization of perivascular and perinecrotic tumor-associated macrophages is probably paramount for overcoming treatment resistance to virtually any treatment.

Short review of SEC, a potential dexamethasone-sparing regimen for glioblastoma: Spironolactone, ecallantide, clotrimazole

This paper presents a short review of data supporting a dexamethasone sparing regimen, SEC, to reduce glioblastoma related brain edema. The conclusion of the reviewed data is that the rationale and risk/benefit ratio favors a pilot study to determine if the three drug regimen of SEC can reduce need for corticosteroid use during the course of glioblastoma. Details of how selected pathophysiological aspects of brain edema occurring during the course of glioblastoma and its treatment intersect with the established action of the three old drugs of SEC indicate that they can be repurposed to reduce that edema. Current first-line treatment of this edema is dexamethasone or related corticosteroids. There are multiple negative prognostic implications of both the edema itself and of dexamethasone, prime among them shortened survival, making a dexamethasone sparing regimen highly desirable. SEC uses spironolactone, an antihypertensive potassium-sparing diuretic acting by mineralocorticoid receptor inhibition, ecallantide acting to inhibit kallikrein activation marketed to treat hereditary angioedema, and clotrimazole, an old antifungal drug that inhibits intermediate conductance Ca++ activated K+ channel (KCa3.1). These three old drugs are well known to most clinicians, have a well-tolerated safety history, and have a robust preclinical database showing their potential to reduce the specific edema of glioblastoma. Additionally, these three drugs were chosen by virtue of each having preclinical evidence of glioblastoma growth and/or migration inhibition independent of their edema reduction action. A clinical study of SEC is being planned.

Engineered Microsystems for Spheroid and Organoid Studies

3D in vitro model systems such as spheroids and organoids provide an opportunity to extend the physiological understanding using recapitulated tissues that mimic physiological characteristics of in vivo microenvironments. Unlike 2D systems, 3D in vitro systems can bridge the gap between inadequate 2D cultures and the in vivo environments, providing novel insights on complex physiological mechanisms at various scales of organization, ranging from the cellular, tissue-, to organ-levels. To satisfy the ever-increasing need for highly complex and sophisticated systems, many 3D in vitro models with advanced microengineering techniques have been developed to answer diverse physiological questions. This review summarizes recent advances in engineered microsystems for the development of 3D in vitro model systems. The relationship between the underlying physics behind the microengineering techniques, and their ability to recapitulate distinct 3D cellular structures and functions of diverse types of tissues and organs are highlighted and discussed in detail. A number of 3D in vitro models and their engineering principles are also introduced. Finally, current limitations are summarized, and perspectives for future directions in guiding the development of 3D in vitro model systems using microengineering techniques are provided.

Satellitosis, a Crosstalk between Neurons, Vascular Structures and Neoplastic Cells in Brain Tumours; Early Manifestation of Invasive Behaviour

The secondary structures of Scherer commonly known as perineuronal and perivascular satellitosis have been identified as a histopathological hallmark of diffuse, invasive, high-grade gliomas. They are recognised as perineuronal satellitosis when clusters of neoplastic glial cells surround neurons cell bodies and perivascular satellitosis when such tumour cells surround blood vessels infiltrating Virchow-Robin spaces. In this review, we provide an overview of emerging knowledge regarding how interactions between neurons and glioma cells can modulate tumour evolution and how neurons play a key role in glioma growth and progression, as well as the role of perivascular satellitosis into mechanisms of glioma cells spread. At the same time, we review the current knowledge about the role of perineuronal satellitosis and perivascular satellitosis within the tumour microenvironment (TME), in order to highlight critical knowledge gaps in research space.

Cerebral organoids: emerging ex vivo humanoid models of glioblastoma

Glioblastoma is an aggressive form of brain cancer that has seen only marginal improvements in its bleak survival outlook of 12-15 months over the last forty years. There is therefore an urgent need for the development of advanced drug screening platforms and systems that can better recapitulate glioblastoma's infiltrative biology, a process largely responsible for its relentless propensity for recurrence and progression. Recent advances in stem cell biology have allowed the generation of artificial tridimensional brain-like tissue termed cerebral organoids. In addition to their potential to model brain development, these reagents are providing much needed synthetic humanoid scaffolds to model glioblastoma's infiltrative capacity in a faithful and scalable manner. Here, we highlight and review the early breakthroughs in this growing field and discuss its potential future role for glioblastoma research.

Extracellular vesicles from organoids and 3D culture systems

When discovered, extracellular vesicles (EVs) such as exosomes were thought of as junk carriers and a means by which the cell disposed of its waste material. Over the years, the role of EVs in cell communication has become apparent with the discovery that the nano-scale vesicles also transport RNA, DNA, and other bioactive components to and from the cells. These findings were originally made in EVs from body fluids of organisms and from in vitro two-dimensional (2D) cell culture models. Recently, organoids and other 3D multicellular in vitro models are being used to study EVs in the context of both physiologic and pathological states. However, standard, reproducible methods are lacking for EV analysis using these models. As a step toward understanding the implications of these platforms, this review provides a comprehensive picture of the progress using 3D in vitro culture models for EV analysis. Translational efforts and regulatory considerations for EV therapeutics are also briefly overviewed to understand what is needed for scale-up and, ultimately, commercialization.

Angiogenic biomaterials to promote therapeutic regeneration and investigate disease progression

The vasculature is a key component of the tissue microenvironment. Traditionally known for its role in providing nutrients and oxygen to surrounding cells, the vasculature is now also acknowledged to provide signaling cues that influence biological outcomes in regeneration and disease. These cues come from the cells that comprise vasculature, as well as the dynamic biophysical and biochemical properties of the surrounding extracellular matrix that accompany vascular development and remodeling. In this review, we illustrate the larger role of the vasculature in the context of regenerative biology and cancer progression. We describe cellular, biophysical, biochemical, and metabolic components of vascularized microenvironments. Moreover, we provide an overview of multidimensional angiogenic biomaterials that have been developed to promote therapeutic vascularization and regeneration, as well as to mimic elements of vascularized microenvironments as a means to uncover mechanisms by which vasculature influences cancer progression and therapy.

Elevated plasma 20S proteasome chymotrypsin-like activity is correlated with IL-8 levels and associated with an increased risk of death in glial brain tumor patients

INTRODUCTION

In cancer treatment an attempt has been made to pharmacologically regulate the proteasome functions, thus the aim was to test whether 20S proteasome chymotrypsin-like (ChT-L) activity has a role in glial brain tumors. Furthermore, we analyzed the correlation between proteasome activity and IL-8, CCL2, NF-κB1 and NF-κB2 concentrations, which impact on brain tumors has already been indicated.

METHODS

Plasma 20S proteasome ChT-L activity was assayed using the fluorogenic peptide substrate Suc-Leu-Leu-Val-Tyr-AMC in the presence of SDS. IL-8, CCL2, NF-κB1 and NF-κB2 concentration was analyzed with the use of ELISA method. Immunohistochemistry for IDH1-R132H was done on 5-microns-thick formalin-fixed, paraffin-embedded tumor sections with the use of antibody specific for the mutant IDH1-R132H protein. Labelled streptavidin biotin kit was used as a detection system.

RESULTS

Brain tumor patients had statistically higher 20S proteasome ChT-L activity (0.649 U/mg) compared to non-tumoral individuals (0.430 U/mg). IDH1 wild-type patients had statistically higher 20S proteasome ChT-L activity (1.025 U/mg) compared to IDH1 mutants (0.549 U/mg). 20S proteasome ChT-L activity in brain tumor patients who died as the consequence of a tumor (0.649) in the following 2 years was statistically higher compared to brain tumor patients who lived (0.430 U/mg). In brain tumor patients the 20S proteasome ChT-L activity positively correlated with IL-8 concentration.

CONCLUSIONS

Elevated 20S proteasome ChT-L activity was related to the increased risk of death in glial brain tumor patients. A positive correlation between 20S proteasome ChT-L activity and IL-8 concentration may indicate the molecular mechanisms regulating glial tumor biology. Thus research on proteasomes may be important and should be carried out to verify if this protein complexes may represent a potential therapeutic target to limit brain tumor invasion.

Characterization of Hen's Egg White To Use It as a Novel Platform To Culture Three-Dimensional Multicellular Tumor Spheroids

We are standardizing protocols to develop egg white (EW) as a cost-effective platform for culture of three-dimensional (3-D) multicellular tumor spheroids for application in understanding tumor microenvironments and drug screening. In this article, we describe several physical and physiological characteristics of EW to use it as 3-D cell culture platform. Field emission scanning electron microscopy revealed the presence of different microstructures. Hydrodynamic size distribution data indicated nano- and micron-sized particles. Rheological measurements revealed the viscosity and viscoelastic behavior appropriate for maintaining cell viability and supporting 3-D cell growth under high-sheer conditions. It was found that thereis no autofluorescence, a requirement for imparting transparency and for microscopic observations of the spheroids. The EW facilitated the development of 3-D tumor spheroids, with an emphasis of difference in cell proliferation and intercellular cytoskeletal organization between two-dimensional and 3-D spheroid cultures. Put together, EW proves to be a cost-affordable and simple platform for 3-D culture of tumor spheroids.

NAC1 attenuates BCL6 negative autoregulation and functions as a BCL6 coactivator of FOXQ1 transcription in cancer cells

Background: Nucleus accumbens-associated protein 1 (NAC1) has multifaceted roles in cancer pathogenesis and progression, including the development of drug resistance, promotion of cytokinesis, and maintenance of “stem cell-like” phenotypes. NAC1 is a transcriptional co-regulator belonging to the bric-a-brac tramtrack broad (BTB) family of proteins, although it lacks the characteristic DNA binding motif of the BTB family. The formation of higher-order transcription complexes likely depends on its interaction with other DNA-binding co-factors.

Results: NAC1 interacts with BCL6 via its C-terminal BEN domain and forms a complex that binds the promoter region and activates transcription of the NAC1 target gene, FOXQ1. NAC1 and BCL6 were coordinately upregulated. Our analysis also identified a novel function of NAC1 in attenuating BCL6 auto-downregulation in ovarian cancer. Lastly, we found a significant overlap among NAC1- and BCL6-regulated genes in tumor cells, suggesting that NAC1 and BCL6 coordinately control transcription in cancer.

Conclusions: The results of this study provide a novel mechanistic insight into the oncogenic roles of NAC1 and underline the importance of developing the NAC1/BCL6-targeted cancer therapy.

Methods: Using the Cistrome database and Chromatin Immunoprecipitation (ChIP) analyses, we identified BCL6 as a potential NAC1- interacting molecule. Co-immunoprecipitation (Co-IP), luciferase reporter assay, immunohistochemistry and microarray analysis were performed to analyze the interaction between NAC1 and BCL6 and the mechanisms by which they regulate the downstream genes including FOXQ1.