CBF1 is clinically prognostic and serves as a target to block cellular invasion and chemoresistance of EMT-like glioblastoma cells

STAT3 phosphorylation inhibitor Bt354 exhibits anti-neoplastic activity in glioblastoma multiforme cells

The high mortality rate of glioblastoma multiforme (GBM), a lethal primary brain tumor, is attributable to postsurgical recurrence. STAT3, an oncogenic protein, is a signal transducer and transcription activator encourages cancer cell migration and proliferation, which results in resistance to therapy. STAT3 inhibition reduces cancer metastasis and improves patient prognosis. Bt354, a small molecule STAT inhibitor, exhibits significant cytotoxic and anti-proliferative activities against certain cancer types. Here, we demonstrated that exposure of GBM cells (U87 MG) to Bt354 had a significant, concentration-dependent growth suppression. Bt354 also induced apoptosis and downregulated the expression of the epithelial-mesenchymal transition genes. Therefore, this study suggests the potential of Bt354 for treating GBM owing to its ability to induce cytotoxicity.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

The Impact of A3AR Antagonism on the Differential Expression of Chemoresistance-Related Genes in Glioblastoma Stem-like Cells

Glioblastoma (GB) is the most aggressive and common primary malignant tumor of the brain and central nervous system. Without treatment, the average patient survival time is about six months, which can be extended to fifteen months with multimodal therapies. The chemoresistance observed in GB is, in part, attributed to the presence of a subpopulation of glioblastoma-like stem cells (GSCs) that are characterized by heightened tumorigenic capacity and chemoresistance. GSCs are situated in hypoxic tumor niches, where they sustain and promote the stem-like phenotype and have also been correlated with high chemoresistance. GSCs have the particularity of generating high levels of extracellular adenosine (ADO), which causes the activation of the A3 adenosine receptor (A3AR) with a consequent increase in the expression and activity of genes related to chemoresistance. Therefore, targeting its components is a promising alternative for treating GB. This analysis determined genes that were up- and downregulated due to A3AR blockades under both normoxic and hypoxic conditions. In addition, possible candidates associated with chemoresistance that were positively regulated by hypoxia and negatively regulated by A3AR blockades in the same condition were analyzed. We detected three potential candidate genes that were regulated by the A3AR antagonist MRS1220 under hypoxic conditions: LIMD1, TRIB2, and TGFB1. Finally, the selected markers were correlated with hypoxia-inducible genes and with the expression of adenosine-producing ectonucleotidases. In conclusion, we detected that hypoxic conditions generate extensive differential gene expression in GSCs, increasing the expression of genes associated with chemoresistance. Furthermore, we observed that MRS1220 could regulate the expression of LIMD1, TRIB2, and TGFB1, which are involved in chemoresistance and correlate with a poor prognosis, hypoxia, and purinergic signaling.

Biosensor-Enhanced Organ-on-a-Chip Models for Investigating Glioblastoma Tumor Microenvironment Dynamics

Glioblastoma, an aggressive primary brain tumor, poses a significant challenge owing to its dynamic and intricate tumor microenvironment. This review investigates the innovative integration of biosensor-enhanced organ-on-a-chip (OOC) models as a novel strategy for an in-depth exploration of glioblastoma tumor microenvironment dynamics. In recent years, the transformative approach of incorporating biosensors into OOC platforms has enabled real-time monitoring and analysis of cellular behaviors within a controlled microenvironment. Conventional in vitro and in vivo models exhibit inherent limitations in accurately replicating the complex nature of glioblastoma progression. This review addresses the existing research gap by pioneering the integration of biosensor-enhanced OOC models, providing a comprehensive platform for investigating glioblastoma tumor microenvironment dynamics. The applications of this combined approach in studying glioblastoma dynamics are critically scrutinized, emphasizing its potential to bridge the gap between simplistic models and the intricate in vivo conditions. Furthermore, the article discusses the implications of biosensor-enhanced OOC models in elucidating the dynamic features of the tumor microenvironment, encompassing cell migration, proliferation, and interactions. By furnishing real-time insights, these models significantly contribute to unraveling the complex biology of glioblastoma, thereby influencing the development of more accurate diagnostic and therapeutic strategies.

Mechanism of Notch Signaling Pathway in Malignant Progression of Glioblastoma and Targeted Therapy

Glioblastoma multiforme (GBM) is the most aggressive form of glioma and the most common primary tumor of the central nervous system. Despite significant advances in clinical management strategies and diagnostic techniques for GBM in recent years, it remains a fatal disease. The current standard of care includes surgery, radiation, and chemotherapy, but the five-year survival rate for patients is less than 5%. The search for a more precise diagnosis and earlier intervention remains a critical and urgent challenge in clinical practice. The Notch signaling pathway is a critical signaling system that has been extensively studied in the malignant progression of glioblastoma. This highly conserved signaling cascade is central to a variety of biological processes, including growth, proliferation, self-renewal, migration, apoptosis, and metabolism. In GBM, accumulating data suggest that the Notch signaling pathway is hyperactive and contributes to GBM initiation, progression, and treatment resistance. This review summarizes the biological functions and molecular mechanisms of the Notch signaling pathway in GBM, as well as some clinical advances targeting the Notch signaling pathway in cancer and glioblastoma, highlighting its potential as a focus for novel therapeutic strategies.

PTX3 activates POSTN and promotes the progression of glioblastoma via the MAPK/ERK signalling axis

BACKGROUND

Intrinsic brain tumours such as glioblastoma (GBM) are believed to develop from neuroglial stem or progenitor cells. GBM accounts for approximately half of gliomas. GBM has a poor prognosis and a low 5-year survival rate. Pentraxin 3 (PTX3) is overexpressed in GBM, but the potential mechanism is unclear.

METHODS

Glioblastoma data from the TCGA and CGGA databases were used to analyse PTX3 expression. Subsequently, in vivo and in vitro experiments were conducted to verify the effect of PTX3 silencing in glioma cells on EMT like process and GSC maintenance. The JASPAR database was used to predict the downstream genes of PTX3. POSTN is a novel target gene of PTX3 in gliomas, and this finding was validated using a luciferase reporter gene assay. Western blotting and KEGG enrichment analysis were used to predict the downstream pathway of POSTN, and it was found that the MAPK/ERK pathway might be related to the function of POSTN.

RESULTS

GBM tissues have higher levels of PTX3 expression than normal brain tissues (NBTs). In functional tests, PTX3 promoted the EMT like process of GBM cells while maintaining the stem cell characteristics of GBM stem cells and enhancing their self-renewal. Moreover, we performed a dual luciferase reporter experiment to confirm that PTX3 binds to the POSTN promoter region. In addition, the expression of key proteins in the MAPK/ERK signalling pathway was increased after PTX3 overexpression.

CONCLUSION

POSTN is a direct target of PTX3 that promotes GBM growth via the MAPK/ERK signalling pathway.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

The Role of Hypoxia and Cancer Stem Cells in Development of Glioblastoma

Glioblastoma multiform (GBM) is recognized as the most malignant brain tumor with a high level of hypoxia, containing a small population of glioblastoma stem like cells (GSCs). These GSCs have the capacity of self-renewal, proliferation, invasion and recapitulating the parent tumor, and are major causes of radio-and chemoresistance of GBM. Upregulated expression of hypoxia inducible factors (HIFs) in hypoxia fundamentally contributes to maintenance and progression of GSCs. Therefore, we thoroughly reviewed the currently acknowledged roles of hypoxia-associated GSCs in development of GBM. In detail, we recapitulated general features of GBM, especially GSC-related features, and delineated essential responses resulted from interactions between GSC and hypoxia, including hypoxia-induced signatures, genes and pathways, and hypoxia-regulated metabolic alterations. Five hypothesized GSC niches are discussed and integrated into one comprehensive concept: hypoxic peri-arteriolar niche of GSCs. Autophagy, another protective mechanism against chemotherapy, is also closely related to hypoxia and is a potential therapeutic target for GBM. In addition, potential causes of therapeutic resistance (chemo-, radio-, surgical-, immuno-), and chemotherapeutic agents which can improve the therapeutic effects of chemo-, radio-, or immunotherapy are introduced and discussed. At last, as a potential approach to reverse the hypoxic microenvironment in GBM, hyperbaric oxygen therapy (HBOT) might be an adjuvant therapy to chemo-and radiotherapy after surgery. In conclusion, we focus on demonstrating the important role of hypoxia on development of GBM, especially by affecting the function of GSCs. Important advantages have been made to understand the complicated responses induced by hypoxia in GBM. Further exploration of targeting hypoxia and GSCs can help to develop novel therapeutic strategies to improve the survival of GBM patients.

Nanomedicines Targeting Glioma Stem Cells

Glioblastoma (GBM), classified as a grade IV glioma, is a rapidly growing, aggressive, and most commonly occurring tumor of the central nervous system. Despite the therapeutic advances, it carries an ominous prognosis, with a median survival of 14.6 months after diagnosis. Accumulating evidence suggests that cancer stem cells in GBM, termed glioma stem cells (GSCs), play a crucial role in tumor propagation, treatment resistance, and tumor recurrence. GSCs, possessing the capacity for self-renewal and multilineage differentiation, are responsible for tumor growth and heterogeneity, leading to primary obstacles to current cancer therapy. In this respect, increasing efforts have been devoted to the development of anti-GSC strategies based on targeting GSC surface markers, blockage of essential signaling pathways of GSCs, and manipulating the tumor microenvironment (GSC niches). In this review, we will discuss the research knowledge regarding GSC-based therapy and the underlying mechanisms for the treatment of GBM. Given the rapid progression in nanotechnology, innovative nanomedicines developed for GSC targeting will also be highlighted from the perspective of rationale, advantages, and limitations. The goal of this review is to provide broader understanding and key considerations toward the future direction of GSC-based nanotheranostics to fight against GBM.

The role of the ZEB1–neuroinflammation axis in CNS disorders

Zinc finger E-box binding homeobox 1 (ZEB1) is a master modulator of the epithelial–mesenchymal transition (EMT), a process whereby epithelial cells undergo a series of molecular changes and express certain characteristics of mesenchymal cells. ZEB1, in association with other EMT transcription factors, promotes neuroinflammation through changes in the production of inflammatory mediators, the morphology and function of immune cells, and multiple signaling pathways that mediate the inflammatory response. The ZEB1–neuroinflammation axis plays a pivotal role in the pathogenesis of different CNS disorders, such as brain tumors, multiple sclerosis, cerebrovascular diseases, and neuropathic pain, by promoting tumor cell proliferation and invasiveness, formation of the hostile inflammatory micromilieu surrounding neuronal tissues, dysfunction of microglia and astrocytes, impairment of angiogenesis, and dysfunction of the blood–brain barrier. Future studies are needed to elucidate whether the ZEB1–neuroinflammation axis could serve as a diagnostic, prognostic, and/or therapeutic target for CNS disorders.

Thermal stress involved in TRPV2 promotes tumorigenesis through the pathways of HSP70/27 and PI3K/Akt/mTOR in esophageal squamous cell carcinoma

BACKGROUND

The transient receptor potential vanilloid receptor 2 (TRPV2) has been found to participate in the pathogenesis of various types of cancers, however, its role(s) in the tumorigenesis of ESCC remain poorly understood.

METHODS

Western blotting and immunohistochemistry were performed to determine the expression profiles of TRPV2 in the ESCC patient tissues. A series of in vitro and in vivo experiments were conducted to reveal the role of TRPV2 in the tumorigenesis of ESCC.

RESULTS

Our study first uncovered that the activation of TRPV2 by recurrent acute thermal stress (54 °C) or O1821 (20 μM) promoted cancerous behaviours in ESCC cells. The pro-angiogenic capacity of the ESCC cells was found to be enhanced profoundly and both tumour formation and metastasis that originated from the cells were substantially promoted in nude mouse models upon the activation of TRPV2. These effects were inhibited significantly by tranilast (120 μM) and abolished by TRPV2 knockout. Conversely, overexpression of TRPV2 could switch the cells to tumorigenesis upon activation of TRPV2. Mechanistically, the driving role of TRPV2 in the progression of ESCC is mainly regulated by the HSP70/27 and PI3K/Akt/mTOR signalling pathways.

CONCLUSIONS

We revealed that TRPV2-PI3K/Akt/mTOR is a novel and promising target for the prevention and treatment of ESCC.

Current Understanding of Hypoxia in Glioblastoma Multiforme and Its Response to Immunotherapy

Simple Summary

Glioblastoma multiforme (GBM) is the most aggressive tumor type in the central nervous system. Hypoxia, defined as a lack of sufficient oxygen in tissues, is the most detrimental factor for the survival of GBM patients, promoting drug resistance, and invasion and inhibition of immune responses. Traditionally, tumor hypoxia has been studied from a narrow viewpoint, excluding the immune system and focusing primarily on the effect of hypoxia on blood vessels and tumor cells. More recently, however, evidence highlighting the important role of immunosurveillance has been uncovered for multiple tumors, including GBM. Thus, connecting the knowledge gained from traditional hypoxia studies with findings from recent immunological studies is urgently needed to better understand the role of hypoxia in cancer.

Abstract

Hypoxia is a hallmark of glioblastoma multiforme (GBM), the most aggressive cancer of the central nervous system, and is associated with multiple aspects of tumor pathogenesis. For example, hypoxia induces resistance to conventional cancer therapies and inhibits antitumor immune responses. Thus, targeting hypoxia is an attractive strategy for GBM therapy. However, traditional studies on hypoxia have largely excluded the immune system. Recently, the critical role of the immune system in the defense against multiple tumors has become apparent, leading to the development of effective immunotherapies targeting numerous cancer types. Critically, however, GBM is classified as a “cold tumor” due to poor immune responses. Thus, to improve GBM responsiveness against immunotherapies, an improved understanding of both immune function in GBM and the role of hypoxia in mediating immune responses within the GBM microenvironment is needed. In this review, we discuss the role of hypoxia in GBM from a clinical, pathological, and immunological perspective.

Recent Development in NKT-Based Immunotherapy of Glioblastoma: From Bench to Bedside

Glioblastoma multiforme (GBM) is an aggressive and dismal disease with a median overall survival of around 15 months and a 5-year survival rate of 7.2%. Owing to genetic mutations, drug resistance, disruption to the blood–brain barrier (BBB)/blood–brain tumor barrier (BBTB), and the complexity of the immunosuppressive environment, the therapeutic approaches to GBM represent still major challenges. Conventional therapies, including surgery, radiotherapy, and standard chemotherapy with temozolomide, have not resulted in satisfactory improvements in the overall survival of GBM patients. Among cancer immunotherapeutic approaches, we propose that adjuvant NKT immunotherapy with invariant NKT (iNKT) and cytokine-induced killer (CIK) cells may improve the clinical scenario of this devastating disease. Considering this, herein, we discuss the current strategies of NKT therapy for GBM based primarily on in vitro/in vivo experiments, clinical trials, and the combinatorial approaches with future therapeutic potential.

Colon cancer cells secreted CXCL11 via RBP-Jκ to facilitated tumour-associated macrophage-induced cancer metastasis

Metastasis is the main cause of colon cancer‐related deaths. RBP‐Jκ is involved in colon cancer development, but its function in colon cancer metastasis is still unclear. Tumour‐associated macrophages are the main cell components in tumour microenvironments. Here, we aimed to determine the function of RBP‐Jκ in colon cancer metastasis and its underlying mechanisms for modulating interactions between colon cancer cell and tumour‐associated macrophages. Through bioinformation analysis, we found that RBP‐Jκ was overexpressed in colon cancer tissues and associated with advanced colon cancer phenotypes, macrophage infiltration and shorter survival overall as confirmed by our patients’ data. And our patients’ data show that RBP‐Jκ expression and tumour‐associated macrophages infiltration are associated with colon cancer metastasis and are independent prognostic factors for colon cancer patients. Tumour‐associated macrophages induced colon cancer cell migration, invasion and epithelial‐mesenchymal transition through secreting TGF‐β1. Colon cancer cells with high RBP‐Jκ expression induced the expression of TGF‐β1 in tumour‐associated macrophages by secreting CXCL11. Our research revealed that colon cancer cells secreted CXCL11 via overexpression of RBP‐Jκ to enhance the expression of TGF‐β1 in tumour‐associated macrophages to further promote metastasis of colon cancer cells.

Bioengineered Models to Study Microenvironmental Regulation of Glioblastoma Metabolism

Despite extensive research and aggressive therapies, glioblastoma (GBM) remains a central nervous system malignancy with poor prognosis. The varied histopathology of GBM suggests a landscape of differing microenvironments and clonal expansions, which may influence metabolism, driving tumor progression. Indeed, GBM metabolic plasticity in response to differing nutrient supply within these microenvironments has emerged as a key driver of aggressiveness. Additionally, emergent biophysical and biochemical interactions in the tumor microenvironment (TME) are offering new perspectives on GBM metabolism. Perivascular and hypoxic niches exert crucial roles in tumor maintenance and progression, facilitating metabolic relationships between stromal and tumor cells. Alterations in extracellular matrix and its biophysical characteristics, such as rigidity and topography, regulate GBM metabolism through mechanotransductive mechanisms. This review highlights insights gained from deployment of bioengineering models, including engineered cell culture and mathematical models, to study the microenvironmental regulation of GBM metabolism. Bioengineered approaches building upon histopathology measurements may uncover potential therapeutic strategies that target both TME-dependent mechanotransductive and biomolecular drivers of metabolism to tackle this challenging disease. Longer term, a concerted effort integrating in vitro and in silico models predictive of patient therapy response may offer a powerful advance toward tailoring of treatment to patient-specific GBM characteristics.

Elevated RBP-Jκ and CXCL11 Expression in Colon Cancer is Associated with an Unfavorable Clinical Outcome

Introduction

This study aims at exploring the expression and significance of recombination signal-binding protein for immunoglobulin kappa J region (RBP-Jκ) and C-X-C motif chemokine 11 (CXCL11) in human colon cancer tissues.

Methods

The RBP-Jκ and CXCL11 expression levels were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) in patients with colon cancer, and their prognostic significance was evaluated.

Results

Through analyzing 342 samples of colon cancer patients treated at our institution, increased expression of RBP-Jκ and CXCL11 was found in human colon cancer specimens compared with matched paratumorous normal specimens (P<0.001). A positive correlation was found between RBP-Jκ expression and CXCL11 expression (P<0.001). High RBP-Jκ expression was significantly associated with poorly differentiated tumors (P=0.005), invasion beyond propria muscularis (P=0.025), lymph node metastases (P=0.005), distant metastasis (P<0.001), advanced tumor-node-metastasis (TNM) stage (P=0.004), and a shorter overall survival (P<0.001). An increase in CXCL11 protein expression was associated with poorly differentiated tumors (P=0.015), invasion beyond propria muscularis (P=0.029), lymph node metastases (P=0.031), distant metastasis (P=0.045), advanced TNM stage (P=0.026), and a shorter overall survival of patients (P<0.001). In multivariate Cox regression analysis, RBP-Jκ protein expression (P=0.036), CXCL11 protein expression (P=0.001), differentiation (P<0.001), depth of invasion (P=0.009), distant metastasis (P<0.001), and TNM stage (P<0.001) were independent prognostic indicators of colon cancer.

Conclusion

High expression of RBP-Jκ is closely associated with high CXCL11 expression, which represents a risk factor for the poor overall survival of colon cancer patients.

WNK3 promotes the invasiveness of glioma cell lines under hypoxia by inducing the epithelial-to-mesenchymal transition

Background

The primary features of malignant glioma include high rates of mortality and recurrence, uncontrollable invasiveness, strong angiogenesis, and widespread hypoxia. The hypoxic microenvironment is an important factor affecting the malignant progression of glioma. However, the molecular mechanisms underlying glioma adaption in hypoxic microenvironments are poorly understood.

Objective

The work presented in this paper focuses on the role of WNK3 gene in glioma invasion under hypoxic conditions. Furthermore, we aim to explore its role in epithelial-to-mesenchymal transition (EMT).

Methods

ShRNA targeting WNK3 transfection was used to knockdown the WNK3 expression in U87 cells. We used western blot analysis to detect the relative expression of proteins in U87 cells. The effect of WNK3 on cell migration was explored using a transwell assay in the U87 cell line. We also evaluated WNK3 expression levels in glioma samples by immunohistochemistry analysis.

Results

WNK3 expression was significantly higher in high-grade (III and IV) gliomas than in low-grade (I and II) gliomas. WNK3 expression was up-regulated in U87 cells when cultured in a hypoxic environment in addition; WNK3 knockdown inhibited the invasion of U87 glioma cells by regulating the EMT, especially under hypoxic conditions.

Conclusion

These findings suggested that WNK3 plays an important role in the hypoxic microenvironment of glioma and might also be a candidate for therapeutic application in the treatment of glioma.

Glioma stem cells and their roles within the hypoxic tumor microenvironment

Tumor microenvironments are the result of cellular alterations in cancer that support unrestricted growth and proliferation and result in further modifications in cell behavior, which are critical for tumor progression. Angiogenesis and therapeutic resistance are known to be modulated by hypoxia and other tumor microenvironments, such as acidic stress, both of which are core features of the glioblastoma microenvironment. Hypoxia has also been shown to promote a stem-like state in both non-neoplastic and tumor cells. In glial tumors, glioma stem cells (GSCs) are central in tumor growth, angiogenesis, and therapeutic resistance, and further investigation of the interplay between tumor microenvironments and GSCs is critical to the search for better treatment options for glioblastoma. Accordingly, we summarize the impact of hypoxia and acidic stress on GSC signaling and biologic phenotypes, and potential methods to inhibit these pathways.

RBPJ contributes to the malignancy of glioblastoma and induction of proneural-mesenchymal transition via IL-6-STAT3 pathway

Notch signaling plays a pivotal role in many cancers, including glioblastoma (GBM). Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) is a key transcription factor of the Notch signaling pathway. Here, we interrogated the function of RBPJ in GBM. Firstly, RBPJ expression of GBM samples was examined. Then, we knocked down RBPJ expression in 2 GBM cell lines (U251 and T98) and 4 glioblastoma (GBM) stem-like cell lines derived from surgical samples of GBM (KGS01, KGS07, KGS10 and KGS15) to investigate the effect on cell proliferation, invasion, stemness, and tumor formation ability. Expression of possible downstream targets of RBPJ was also assessed. RBPJ was overexpressed in the GBM samples, downregulation of RBPJ reduced cell proliferation and the invasion ability of U251 and T98 cells and cell proliferation ability and stemness of glioblastoma stem-like cells (GSC) lines. These were accompanied by reduced IL-6 expression, reduced activation of STAT3, and inhibited proneural-mesenchymal transition (PMT). Tumor formation and PMT were also impaired by RBPJ knockdown in vivo. In conclusion, RBPJ promotes cell proliferation, invasion, stemness, and tumor initiation ability in GBM cells through enhanced activation of IL-6-STAT3 pathway and PMT, inhibition of RBPJ may constitute a prospective treatment for GBM.

Galangin (GLN) Suppresses Proliferation, Migration, and Invasion of Human Glioblastoma Cells by Targeting Skp2-Induced Epithelial-Mesenchymal Transition (EMT)

Background

Galangin (GLN), a pure natural flavonoid compound found in plants, has been shown to exert anti-cancer effects against multiple cancer types, including glioma. However, its underlying molecular mechanism remains unclear. Epithelial-to-mesenchymal transition (EMT) performs an important function in the genesis and development of cancer. Skp2, a pivotal component of SCF^Skp2 E3 ubiquitin ligase, has been shown to function as an oncogene in GBM invasion that contributes to the EMT process. Thus, we explored whether GLN inhibited Skp2-mediated EMT and the mechanism underlying the Skp2 degradation pathway.

Methods

CCK-8 assay, wound healing assay and transwell assay were used to examine cell proliferation, migration, and invasion after treatment with or without GLN. RT-PCR and Western blotting analysis were performed to evaluate mRNA and protein expression, respectively. Co-immunoprecipitation was conducted to detect ubiquitinated Skp2 levels in vitro and in vivo after GLN treatment. Bioluminescence imaging was performed to examine the intracranial tumor size of U87 xenograft mice. Microscale thermophoresis (MST) experiment was used to detect interactions between Skp2 and GLN.

Results

GLN suppressed GBM cell growth, migration, and invasion, and also downregulated the expression of Skp2 and mesenchymal markers (Zeb1, N-cadherin, snail, vimentin) in vitro. Moreover, the overexpression of Skp2 in GBM cells decreased the effect of GLN on EMT. Furthermore, we demonstrated that GLN degraded skp2 protein through the ubiquitination proteasome pathway and directly interacted with skp2 protein, as shown through the MST assay.

Conclusion

This study is the first to identify Skp2 as a novel target of GLN for the treatment of GBM and report of Skp2 protein degradation in a ubiquitination proteasome pathway. Results from our study indicated the potential of GLN for the treatment of GBM through ubiquitin-mediated degradation of Skp2.

Inhibition of Notch1 reverses EMT and chemoresistance to cisplatin via direct downregulation of MCAM in triple-negative breast cancer cells

Resistance to chemotherapy continues to be a critical issue in the clinical therapy of triple-negative breast cancer (TNBC). Epithelial-mesenchymal transition (EMT) is thought to contribute to chemoresistance in several cancer types, including breast cancer. Identification of the key signaling pathway that regulates the EMT program and contributes to chemoresistance in TNBC will provide a novel strategy to overcome chemoresistance in this subtype of cancer. Herein, we demonstrate that Notch1 positively associates with melanoma cell adhesion molecule (MCAM), a unique EMT activator, in TNBC tissue samples both at mRNA and protein levels. High expression of Notch1 and MCAM both predicts a poor survival in basal-like/TNBC patients, particularly in those treated with chemotherapy. The expression of Notch1 and MCAM in MDA-MB-231 cells gradually increases in a time-dependent manner when exposing to low dose cisplatin. Moreover, the expressions of Notch1 and MCAM in cisplatin-resistant MDA-MB-231 cells are significantly higher than wild-type counterparts. Notch1 promotes EMT and chemoresistance, as well as invasion and proliferation of TNBC cells via direct activating MCAM promoter. Inhibition of Notch1 significantly downregulates MCAM expression, resulting in the reversion of EMT and chemoresistance to cisplatin in TNBC cells. Our study reveals the regulatory mechanism of the Notch1 pathway and MCAM in TNBC and suggesting that targeting the Notch1/MCAM axis, in conjunction with conventional chemotherapies, might be a potential avenue to enhance the therapeutic efficacy for patients with TNBC.

Hypoxia in solid tumors: a key promoter of cancer stem cell (CSC) resistance

PURPOSE

Cancer stem cells (CSCs) are highly tumorigenic cell types that reside within specific areas of tumor microenvironment (TME), and are endowed with self-renewal and resistance properties. Here, we aimed to discuss mechanisms involved in hypoxia-derived CSC resistance and targeting for effective cancer therapy.

RESULTS

Preferential localization within hypoxic niches would help CSCs develop adaptive mechanisms, mediated through the modification of responses to various stressors and, as a result, show a more aggressive behavior.

CONCLUSION

Hypoxia, in fact, serves as a multi-tasking strategy to nurture CSCs with this adaptive capacity, complexing targeted therapies.

FOX-A1 contributes to acquisition of chemoresistance in human lung adenocarcinoma via transactivation of SOX5

Background

Chemoresistance is a major obstacle for the effective treatment of lung adenocarcinoma (LAD). Forkhead box (FOX) proteins have been demonstrated to play critical roles in promoting epithelial-mesenchymal transition (EMT) and chemoresistance. However, whether FOX proteins contribute to the acquisition of EMT and chemoresistance in LAD remains largely unknown.

Methods

FOX-A1 expression was measured in LAD cells and tissues by qRT-PCR. The expression levels of EMT markers were detected by western blotting and immunofluorescence assay. The interaction between Sex determining region Y-box protein 5 (SOX5) and FOX-A1 was validated by chromatin immunoprecipitation sequence (ChIP-seq) and Chromatin immunoprecipitation (ChIP) assay. Kaplan-Meier analysis and multivariate Cox regression analysis were performed to analyze the significance of FOX-A1 and SOX5 expression in the prognosis of LAD patients.

Findings

FOX-A1 was upregulated in docetaxel-resistant LAD cells. High FOX-A1 expression was closely associated with a worse prognosis. Upregulation of FOX-A1 in LAD samples indicated short progression-free survival (PFS) and overall survival (OS). SOX5 is a new and direct target of FOX-A1 and was positively regulated by FOX-A1 in LAD cell lines. Knockdown of FOX-A1 or SOX5 reversed the chemoresistance of docetaxel-resistant LAD cells by suppressing cell proliferation, migration and EMT progress.

Interpretation

These data elucidated an original FOX-A1/SOX5 pathway that represents a promising therapeutic target for chemosensitizing LAD and provides predictive biomarkers for evaluating the efficacy of chemotherapies.

Role of Notch Signaling Pathway in Glioblastoma Pathogenesis

Notch signaling is an evolutionarily conserved pathway that regulates important biological processes, such as cell proliferation, apoptosis, migration, self-renewal, and differentiation. In mammals, Notch signaling is composed of four receptors (Notch1–4) and five ligands (Dll1-3–4, Jagged1–2) that mainly contribute to the development and maintenance of the central nervous system (CNS). Neural stem cells (NSCs) are the starting point for neurogenesis and other neurological functions, representing an essential aspect for the homeostasis of the CNS. Therefore, genetic and functional alterations to NSCs can lead to the development of brain tumors, including glioblastoma. Glioblastoma remains an incurable disease, and the reason for the failure of current therapies and tumor relapse is the presence of a small subpopulation of tumor cells known as glioma stem cells (GSCs), characterized by their stem cell-like properties and aggressive phenotype. Growing evidence reveals that Notch signaling is highly active in GSCs, where it suppresses differentiation and maintains stem-like properties, contributing to Glioblastoma tumorigenesis and conventional-treatment resistance. In this review, we try to give a comprehensive view of the contribution of Notch signaling to Glioblastoma and its possible implication as a target for new therapeutic approaches.

NEO212, a conjugate of temozolomide and perillyl alcohol, blocks the endothelial-to-mesenchymal transition in tumor-associated brain endothelial cells in glioblastoma

As the endothelial-to-mesenchymal transition (EndMT) supports the pro-angiogenic and invasive characteristics of glioblastoma multiforme (GBM), blocking this process would be a promising approach to inhibit tumor progression and recurrence. Here, we demonstrate that glioma stem cells (GSC) induce EndMT in brain endothelial cells (BEC). TGF-β signaling is necessary, but not sufficient to induce this EndMT process. Cell-to-cell contact and the contribution of Notch signaling are also required. NEO212, a conjugate of temozolomide and perillyl alcohol, blocks EndMT induction and reverts the mesenchymal phenotype of tumor-associated BEC (TuBEC) by blocking TGF-β and Notch pathways. Consequently, NEO212 reduces the invasiveness and pro-angiogenic properties associated with TuBEC, without affecting control BEC. Intracranial co-implantation of BEC and GSC in athymic mice showed that EndMT occurs in vivo, and can be blocked by NEO212, supporting the potential clinical value of NEO212 for the treatment of GBM.

Ars2 promotes cell proliferation and tumorigenicity in glioblastoma through regulating miR-6798-3p

Arsenic resistance protein 2 (Ars2) is a component of the nuclear RNA cap-binding complex (CBC) that is important for some microRNA biogenesis and it is critical for cell proliferation and tumorigenicity. However, mechanism of Ars2-regulated cellular proliferation and tumorigenicity in glioblastoma has not been fully understood. Western blotting was used to detect the expressions of Ars2, p53, p21, and cleavage/activation of caspases-3 (C-Caspase 3). Microarray and Quantitative Real-time PCR (qRT-PCR) were performed to identify the Ars2-regulated microRNAs. Apoptosis assessed by flow cytometry analysis was used to evaluate the role of Ars2 in cells proliferation. The lentivirus-mediated gene knockdown approach was conducted to determine the function of Ars2. The orthotopic glioblastoma xenograft was used to demonstrate the role of Ars2 in glioblastoma growth in vivo. The high expression of Ars2 was observed in several glioblastoma cell lines and was significantly associated with poorer overall survival. Importantly, the overexpression of Ars2 promoted cell proliferation and colony formation in glioblastoma cells, whereas the depletion of Ars2 inhibited cell proliferation, colony formation, and tumor growth. Mechanistic study revealed that knockdown of Ars2 reduced the expression levels of miR-6798-3p, which was responsible for the up-regulation of p53 and p21, leading to apoptosis. Furthermore, the knockdown of Ars2 suppressed tumor growth in orthotopic glioblastoma xenograft model and significantly prolonged the survival time of the tumor-bearing mice. These findings identify a critical role for Ars2 in regulation of proliferation and tumorigenicity in glioblastoma and suggest that Ars2 could be a critical therapeutic target for glioblastoma intervention.

Targeting the Notch1 oncogene by miR-139-5p inhibits glioma metastasis and epithelial-mesenchymal transition (EMT)

BACKGROUND

Glioma metastasis, invasion, epithelial-mesenchymal transition (EMT) and chemoresistance indicate poor prognosis. Accumulating evidence reveals that Notch1 is an important factor in tumour progression. However, the role of Notch1 in glioma EMT and associated microRNAs (miRNAs) with the Notch pathway remain controversial.

METHODS

Utilizing cBioPortal database to examine the gene signature of NOTCH1 (encoding Notch1), CDH2 (encoding N-cadherin) and SNAI1 (encoding Snail-1) in disease-free survival (DFS) and overall survival (OS). We analyzed the Notch1 expression from Oncomine. We used Western blot (WB), immunohistochemistry (IHC) and immunofluorescence to determine protein levels. Transcription was evaluated by quantitative real-time (qRT)-PCR. siRNA and lentivirus were used to knock down Notch1 and overexpress miR-139-5p, respectively. The migration and invasion of glioma cells were assessed by wound healing and transwell assays. Luciferase reporter assays were utilized to verify the relationship between Notch1 and miR-139-5p. A U87-implanted intracranial model was used to study the effect of miR-139-5p on tumour growth and Notch1 suppression efficacy or EMT reversion.

RESULTS

It revealed the association of NOTCH1, CDH2, SNAI1 genomic alterations with decreases in DFS and OS. Notch1 was upregulated in classical and proneural subtypes of GBM, and associated with tumour grade. Notch1 inhibition suppressed the biological behaviours of metastasis, invasion and EMT. Notch1 was identified as a novel direct target of miR-139-5p. MiR-139-5p overexpression partially phenocopied Notch1 siRNA, whereas the forced expression of Notch1 reversed the effects of miR-139-5p on the invasion of glioma. Moreover, intracranial tumourigenicity and EMT behaviours were reduced by the introduction of miR-139-5p and partially mediated by the decreased Notch1 expression.

CONCLUSIONS

miR-139-5p was identified as a tumour suppressor by negatively targeting Notch1, and this work suggests a possible molecular mechanism of the miR-139/Notch1/EMT axis for glioma treatment.

Molecular mechanism of Notch signaling with special emphasis on microRNAs: Implications for glioma

Glioma is the most aggressive primary brain tumor and is notorious for resistance to chemoradiotherapy. Although its associated mechanisms are still not completely understood, Notch signaling, an evolutionarily conserved pathway, appears to be the key processes involved. Nevertheless, its mechanisms are sophisticated, due to a variety of targets and signal pathways, especially microRNA. MicroRNAs, which are small noncoding regulatory RNA molecules, have been proposed as one of the key mechanisms in glioma pathogenesis. Among the known glioma associated microRNA, microRNA-129, microRNA-34 family, and microRNA-326 have been shown to influence the progress of glioma through Notch signaling. Evidence also indicates that recurrence is due to development or persistence of the glioma stem-like cells and active angiogenesis, which are tightly regulated by a variety of factors, including Notch signaling. In this review, we summarize the recent progress regarding the functional roles of Notch signaling in glioma, including Notch ligand, microRNA, intracellular crosstalk, glioma stem-like cells and active angiogenesis and explore their clinical implications as diagnostic or prognostic biomarkers and molecular therapeutic targets for glioma.

The Role of Hypoxia in Glioblastoma Invasion

Glioblastoma multiforme (GBM), a grade IV astrocytoma, is the most common and deadly type of primary malignant brain tumor, with a patient's median survival rate ranging from 15 to 17 months. The current treatment for GBM involves tumor resection surgery based on MRI image analysis, followed by radiotherapy and treatment with temozolomide. However, the gradual development of tumor resistance to temozolomide is frequent in GBM patients leading to subsequent tumor regrowth/relapse. For this reason, the development of more effective therapeutic approaches for GBM is of critical importance. Low tumor oxygenation, also known as hypoxia, constitutes a major concern for GBM patients, since it promotes cancer cell spreading (invasion) into the healthy brain tissue in order to evade this adverse microenvironment. Tumor invasion not only constitutes a major obstacle to surgery, radiotherapy, and chemotherapy, but it is also the main cause of death in GBM patients. Understanding how hypoxia triggers the GBM cells to become invasive is paramount to developing novel and more effective therapies against this devastating disease. In this review, we will present a comprehensive examination of the available literature focused on investigating how GBM hypoxia triggers an invasive cancer cell phenotype and the role of these invasive proteins in GBM progression.

Overexpression of COX7A2 is associated with a good prognosis in patients with glioma

Cytochrome c oxidase subunit 7A2 (COX7A2) is a nuclear-encoded polypeptide involved in assembly and regulation of cytochrome c oxidase (COX). Changes in the respiratory chain as big complex are known to be associated with cancer, but little research has been performed to discover COX7A2 as a prognostic marker in glioma. In the present study, we investigated COX7A2 expression and its prognostic significance in glioma. Glioma surgical tissue samples were taken from 126 patients who had been followed up from 4 to 51 months. Immunohistochemistry were used to test COX7A2 expression in the 126 tumor samples. Eighty-six of 126 (68.3%) paraffin-embedded glioma biopsies showed high expression of COX7A2. Statistical analysis displayed that there was significant difference of COX7A2 expression level in patients categorized according to WHO classification. Kaplan-Meier survival analysis revealed that patients with higher COX7A2 expression had longer overall survival time and better prognosis. R2: microarray analysis based on Tumor Glioma French 284 database, Tumor Glioblastoma TCGA 540 database, and Tumor Glioma Kawaguchi 50 database testified that high expression of COX7A2 is associated with a good prognosis in patients with glioma. Multivariate analysis showed that COX7A2 high expression was an independent prognostic indicator for survival. Our results suggest that COX7A2 could be served as a valuable prognostic marker of glioma.