Ibrutinib inactivates BMX-STAT3 in glioma stem cells to impair malignant growth and radioresistance

Local delivery of ibrutinib by folate receptor-mediated targeting PLGA-PEG nanoparticles to glioblastoma multiform: in vitro and in vivo studies

Glioblastoma multiforme (GBM) is a widespread and life-threatening kind of brain cancer, which has a high mortality rate. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, irreversibly adheres to a conserved cysteine residue of two enzymes BTK and BMX, inhibiting their kinase activities, which leads to suppression of the growth of glioma cells. This study synthesised PLGA-PEG-folate (PPF) polymer and subsequently encapsulated ibrutinib within PPF nanoparticles (IBT-PPF-NPs). H NMR spectra confirmed the synthesis of PPF polymer. The efficiency of IBT-PPF-NPs was 97 ± 2.26% with 8.8 ± 0.2% drug loading. The particle size was 208 ± 4.8 nm. The IC50 value of free ibrutinib, IB-PPF-NPs and ibrutinib encapsulated in PLGA NPs (IB-P-NPs) was 10.2, 7.6 and 10.13 µM in C6 cell lines, whereas in U-87 MG cells was 24.4, 16 and 25.2 µM, respectively. The cellular uptake of FITC-PPF-NPs increased from 47.6% to 90.3% in C6 cells and from 55% to 97.3% in U-87 MG cells compared to FITC-P-NPs. The in vivo results indicate a significant reduction in tumour size in treatment groups in comparison to control groups, while the group that received the intratumoural injection of IB-PPF-NPs exhibited a greater reduction. The folate-targeting agent enhances the nanoparticles' effectiveness by promoting their uptake through the endocytosis pathway.

Discovery of IHMT-15130 as a Highly Potent Irreversible BMX Inhibitor for the Treatment of Myocardial Hypertrophy and Remodeling

Cardiac hypertrophy is usually accompanied by many forms of heart disease, including hypertension, vascular disease, ischemic disease, and heart failure, and thus effectively predicts the increased cardiovascular morbidity and mortality. Bone marrow kinase in chromosome X (BMX) has been reported to be the major signaling transduction protein in cardiac arterial endothelial cells and is thought to be involved in the pathology of cardiac hypertrophy. We report here the discovery of a potent irreversible BMX kinase inhibitor, IHMT-15130, which covalently targets cysteine 496 of BMX and exhibits potent inhibitory activity against BMX kinase (IC50: 1.47 ± 0.07 nM). Compared to recently approved BTK/BMX dual inhibitor Ibrutinib, IHMT-15130 displayed selectivity over CSK kinase (IC50 > 25,000 nM), targeting of which may cause severe atrial fibrillation and bleeding. IHMT-15130 effectively reduced the secretion of inflammatory cytokines, inhibited the inflammatory signaling pathway in vitro and in vivo, and alleviated angiotensin II (Ang II)-induced myocardial hypertrophy in a murine model. This study provides further experimental evidence for the application of BMX kinase inhibitors in the treatment of cardiac hypertrophy.

Lactylation-driven USP4-mediated ANXA2 stabilization and activation promotes maintenance and radioresistance of glioblastoma stem cells

Glioblastoma (GBM) is the most primary lethal brain cancer, characterized by the presence of glioblastoma stem cells (GSCs) that initiate and sustain tumor growth and induce radioresistance. Annexin A2 (ANXA2) has been reported to contribute to glioblastoma progression and impart stem cell-like properties to GSCs, however, its post-translational modifications and mechanisms in GSCs maintenance remain poorly understood. Here, we identify that USP4 is preferentially expressed by GSCs in GBM, USP4/ANXA2 supports GSCs maintenance and radioresistance. Specifically, USP4 interacts with ANXA2, stabilizing its protein by deubiquitinating ANXA2, which mediates its proteasomal degradation and Y24 phosphorylation. USP4 directly cleaves Lys48- and Lys63-linked polyubiquitin chains of ANXA2, with the Lys63-linked polyubiquitin chains of ANXA2 K28 mediating its Y24 phosphorylation. Moreover, K10 acetylation of ANXA2 enhances its interaction with USP4. Importantly, USP4/ANXA2 promotes GSCs maintenance and radioresistance by activating BMX-mediated STAT3 activation. H3K18 lactylation is responsible for the upregulation of USP4 in GSCs. Our studies reveal that USP4/ANXA2 plays critical roles in maintaining GSCs and therapeutic resistance, highlighting the importance of lactylation, acetylation, ubiquitination, and phosphorylation as critical post-translational modifications for USP4-mediated stabilization and activity of ANXA2.

Design, Synthesis, and Mechanism Study of Novel BMX Inhibitors Based on the Core of 1,3,5-Triazin-2-Amine for the Treatment of Gastric Carcinoma

BMX, a member of the Tec family of kinases, plays a pivotal role in the occurrence and progression of cancers and multiple chronic inflammations. However, there are rarely BMX inhibitors reported, and the signaling pathways mediated by BMX are still poorly understood. In this study, a series of novel BMX inhibitors bearing the core of 1,3,5-triazin-2-amine were designed and synthesized by structural modifications from the lead compound B1c. Among them, compound B6a irreversibly and selectively inhibited BMX (IC50 = 12 nM) and displayed good antiproliferative activities in various cancer cell lines. A mechanism study in gastric carcinoma HGC-27 and MGC-803 cells revealed that B6a promoted cell cycle arrest and apoptosis, triggered protective autophagy, and suppressed the BMX/AKT/mTOR pathway. Notably, although B6a's bioavailability was extremely low, it still exhibited excellent antitumor potency in the HGC-27 xenograft model with high safety, demonstrating that B6a was a promising BMX inhibitor and worth further exploration.

Inhibition of proteolytic and ATPase activities of the proteasome by the BTK inhibitor CGI-1746

Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, has been shown to synergize in vitro with proteasome inhibitors (PIs) in reducing the viability of cells derived from B cell malignancies, but the mechanism is not known. We report here that an off-target effect of ibrutinib causes synergy because not all BTK inhibitors exhibited the synergistic effect, and those that synergized did so even in cells that do not express BTK. The allosteric BTK inhibitor CGI-1746 showed the strongest synergy. Co-treatment of cells with CGI-1746 increased PI-induced accumulation of ubiquitin conjugates and expression of heat shock proteins and NOXA and decreased a ratio of reduced to oxidized glutathione. CGI-1746, but not other BTK inhibitors, inhibited ATPase activity and all three peptidase activities of the 26S proteasome. The effect demonstrates a conceptually novel mode of proteasome inhibition that may aid the development of more potent PIs.

Brain targeted biomimetic siRNA nanoparticles for drug resistance glioblastoma treatment

Glioblastoma multiforme (GBM), the most aggressive intracranial neoplasm, remains incurable at present, primarily due to drug resistance, which significantly contributes to elevated recurrence rates and dismal prognosis. Signal transducer and activator of transcription 3 (STAT3) is a critical gene closely associated with GBM drug resistance and the progression of GBM stem cells (GSCs), making it a promising therapeutic target. In this study, we developed cancer cell membrane-cloaked biomimetic nanoparticles to deliver STAT3 siRNA to reverse drug resistance in homologous GBM. These biomimetic nanoparticles leverage homotypic targeting, rapid endosome escape, and fast siRNA release, leading to efficient in vitro STAT3 knockdown in both temozolomide-resistant U251-TR cells and X01 GSCs. Moreover, benefited from the membrane functionalization, significant prolonged blood circulation, improved blood brain barrier (BBB) penetration and GBM tumor accumulation are achieved by these siRNA biomimetic nanoparticles. Importantly, these nanoparticles effectively inhibit tumor proliferation, significantly extending median survival time in orthotopic U251-TR (43.5 d versus 20 d for PBS control) and X01 GSC-bearing mouse xenografts (52 d versus 19.5 d for PBS control). Altogether, this biomimetic siRNA platform offers a promising strategy for gene therapy targeting drug-resistant GBM.

Ibrutinib as treatment for Bing-Neel syndrome reclassified as glioblastoma: a case report

BACKGROUND

Glioblastoma is a highly malignant disease with limited treatment options. Ibrutinib, a covalent Bruton tyrosine kinase inhibitor, is an oral agent with manageable side effects used for hematological diseases including Waldenström macroglobulinemia. We present the case of a 69-year-old Caucasian male patient treated with ibrutinib for suspected Bing-Neel syndrome (BNS), which following a biopsy, was reclassified as glioblastoma.

CASE PRESENTATION

In December 2018, a 69-year-old Caucasian male patient was diagnosed with Waldenström macroglobulinemia. As the patient was asymptomatic, without bone marrow failure or high M-component count, watchful waiting was initiated. Due to increasing neurological symptoms, the patient, based on magnetic resonance imaging, was diagnosed with Bing-Neel syndrome in May 2019. The patient received different treatments before starting ibrutinib monotherapy in August 2019 due to disease progression, both on magnetic resonance imaging and clinically. The patient remained clinically stable for 7 months. In March 2020, the patient developed headaches, and both magnetic resonance imaging and a biopsy revealed glioblastoma IDH-wildtype. Treatment was changed in line with the new diagnosis, but the patient died at the end of 2020.

CONCLUSION

We present a case in which a patient with glioblastoma IDH-wildtype remained clinically stable for 7 months when treated with ibrutinib monotherapy, which is similar to what would be expected for the standard treatment for glioblastoma. To our knowledge, this is the first patient receiving ibrutinib for a glioblastoma IDH-wildtype with a meaningful clinical outcome. Our case may therefore support previous nonclinical findings, indicating a therapeutic value of ibrutinib in patients with glioblastoma and support for further investigation of ibrutinib as a possible treatment for glioblastoma.

Lactoferrin/CD133 antibody conjugated nanostructured lipid carriers for dual targeting of blood-brain-barrier and glioblastoma stem cells

The main reasons for the difficulty in curing and high recurrence rate of glioblastoma multiforme (GBM) include: 1. The difficulty of chemotherapy drugs in penetrating the blood-brain barrier (BBB) to target tumor cells; 2. The presence of glioma stem cells (GSCs) leading to chemotherapy resistance. Therefore, breaking through the limitations of the BBB and overcoming the drug resistance caused by GSCs are the main strategies to address this problem. This study presents our results on the development of lactoferrin (Lf)/CD133 antibody conjugated nanostructured lipid carriers (Lf/CD133-NLCS) for simultaneously targeting BBB and GSCs. Temozolomide (TMZ) loaded Lf/CD133-NLCS (Lf/CD133-NLCS-TMZ) exhibited high-efficiencyin vitroanti-tumor effects toward malignant glioma cells (U87-MG) and GSCs, while demonstrating no significant toxicity to normal cells at concentrations lower than 200 μg ml-1. The results of thein vitrotargeting GBM study revealed a notably higher cellular uptake of Lf/CD133-NLCS-TMZ in U87-MG cells and GSCs in comparison to Lf/CD133 unconjugated counterpart (NLCS-TMZ). In addition, increased BBB permeability were confirmed for Lf/CD133-NLCS-TMZ compared to NLCS-TMZ bothin vitroandin vivo. Taking together, Lf/CD133-NLCS-TMZ show great potential for dual targeting of BBB and GSCs, as well as GBM therapy based on this strategy.

Preclinical spheroid models identify BMX as a therapeutic target for metastatic MYCN nonamplified neuroblastoma

The development of targeted therapies offers new hope for patients affected by incurable cancer. However, multiple challenges persist, notably in controlling tumor cell plasticity in patients with refractory and metastatic illness. Neuroblastoma (NB) is an aggressive pediatric malignancy originating from defective differentiation of neural crest-derived progenitors with oncogenic activity due to genetic and epigenetic alterations and remains a clinical challenge for high-risk patients. To identify critical genes driving NB aggressiveness, we performed combined chromatin and transcriptome analyses on matched patient-derived xenografts (PDXs), spheroids, and differentiated adherent cultures derived from metastatic MYCN nonamplified tumors. Bone marrow kinase on chromosome X (BMX) was identified among the most differentially regulated genes in PDXs and spheroids versus adherent models. BMX expression correlated with high tumor stage and poor patient survival and was crucial to the maintenance of the self-renewal and tumorigenic potential of NB spheroids. Moreover, BMX expression positively correlated with the mesenchymal NB cell phenotype, previously associated with increased chemoresistance. Finally, BMX inhibitors readily reversed this cellular state, increased the sensitivity of NB spheroids toward chemotherapy, and partially reduced tumor growth in a preclinical NB model. Altogether, our study identifies BMX as a promising innovative therapeutic target for patients with high-risk MYCN nonamplified NB.

Glioma Stem Cells as Promoter of Glioma Progression: A Systematic Review of Molecular Pathways and Targeted Therapies

Gliomas' aggressive nature and resistance to therapy make them a major problem in oncology. Gliomas continue to have dismal prognoses despite significant advancements in medical science, and traditional treatments like surgery, radiation (RT), and chemotherapy (CT) frequently prove to be ineffective. After glioma stem cells (GSCs) were discovered, the traditional view of gliomas as homogeneous masses changed. GSCs are essential for tumor growth, treatment resistance, and recurrence. These cells' distinct capacities for differentiation and self-renewal are changing our knowledge of the biology of gliomas. This systematic literature review aims to uncover the molecular mechanisms driving glioma progression associated with GSCs. The systematic review adhered to PRISMA guidelines, with a thorough literature search conducted on PubMed, Ovid MED-LINE, and Ovid EMBASE. The first literature search was performed on 1 March 2024, and the search was updated on 15 May 2024. Employing MeSH terms and Boolean operators, the search focused on molecular mechanisms associated with GCSs-mediated glioma progression. Inclusion criteria encompassed English language studies, preclinical studies, and clinical trials. A number of 957 papers were initially identified, of which 65 studies spanning from 2005 to 2024 were finally included in the review. The main GSC model distribution is arranged in decreasing order of frequency: U87: 20 studies (32.0%); U251: 13 studies (20.0%); A172: 4 studies (6.2%); and T98G: 2 studies (3.17%). From most to least frequent, the distribution of the primary GSC pathway is as follows: Notch: 8 studies (12.3%); STAT3: 6 studies (9.2%); Wnt/β-catenin: 6 studies (9.2%); HIF: 5 studies (7.7%); and PI3K/AKT: 4 studies (6.2%). The distribution of molecular effects, from most to least common, is as follows: inhibition of differentiation: 22 studies (33.8%); increased proliferation: 18 studies (27.7%); enhanced invasive ability: 15 studies (23.1%); increased self-renewal: 5 studies (7.7%); and inhibition of apoptosis: 3 studies (4.6%). This work highlights GSC heterogeneity and the dynamic interplay within the glioblastoma microenvironment, underscoring the need for a tailored approach. A few key pathways influencing GSC behavior are JAK/STAT3, PI3K/AKT, Wnt/β-catenin, and Notch. Therapy may target these pathways. This research urges more study to fill in knowledge gaps in the biology of GSCs and translate findings into useful treatment approaches that could improve GBM patient outcomes.

MicroRNAs as the pivotal regulators of Temozolomide resistance in glioblastoma

Glioblastoma (GBM) is an aggressive nervous system tumor with a poor prognosis. Although, surgery, radiation therapy, and chemotherapy are the current standard protocol for GBM patients, there is still a poor prognosis in these patients. Temozolomide (TMZ) as a first-line therapeutic agent in GBM can easily cross from the blood-brain barrier to inhibit tumor cell proliferation. However, there is a high rate of TMZ resistance in GBM patients. Since, there are limited therapeutic choices for GBM patients who develop TMZ resistance; it is required to clarify the molecular mechanisms of chemo resistance to introduce the novel therapeutic targets. MicroRNAs (miRNAs) regulate chemo resistance through regulation of drug metabolism, absorption, DNA repair, apoptosis, and cell cycle. In the present review we discussed the role of miRNAs in TMZ response of GBM cells. It has been reported that miRNAs mainly induced TMZ sensitivity by regulation of signaling pathways and autophagy in GBM cells. Therefore, miRNAs can be used as the reliable diagnostic/prognostic markers in GBM patients. They can also be used as the therapeutic targets to improve the TMZ response in GBM cells.

Identification of hypoxic macrophages in glioblastoma with therapeutic potential for vasculature normalization

Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart a spatially resolved transcriptional landscape of Mo-TAMs across 51 patients with isocitrate dehydrogenase (IDH)-wild-type glioblastomas or IDH-mutant gliomas. We characterize a Mo-TAM subset that is localized to the peri-necrotic niche and skewed by hypoxic niche cues to acquire a hypoxia response signature. Hypoxia-TAM destabilizes endothelial adherens junctions by activating adrenomedullin paracrine signaling, thereby stimulating a hyperpermeable neovasculature that hampers drug delivery in glioblastoma xenografts. Accordingly, genetic ablation or pharmacological blockade of adrenomedullin produced by Hypoxia-TAM restores vascular integrity, improves intratumoral concentration of the anti-tumor agent dabrafenib, and achieves combinatorial therapeutic benefits. Increased proportion of Hypoxia-TAM or adrenomedullin expression is predictive of tumor vessel hyperpermeability and a worse prognosis of glioblastoma. Our findings highlight Mo-TAM diversity and spatial niche-steered Mo-TAM reprogramming in diffuse gliomas and indicate potential therapeutics targeting Hypoxia-TAM to normalize tumor vasculature.

A review on potential heterocycles for the treatment of glioblastoma targeting receptor tyrosine kinases

Glioblastoma, the most aggressive form of brain tumor, poses significant challenges in terms of treatment success and patient survival. Current treatment modalities for glioblastoma include radiation therapy, surgical intervention, and chemotherapy. Unfortunately, the median survival rate remains dishearteningly low at 12-15 months. One of the major obstacles in treating glioblastoma is the recurrence of tumors, making chemotherapy the primary approach for secondary glioma patients. However, the efficacy of drugs is hampered by the presence of the blood-brain barrier and multidrug resistance mechanisms. Consequently, considerable research efforts have been directed toward understanding the underlying signaling pathways involved in glioma and developing targeted drugs. To tackle glioma, numerous studies have examined kinase-downstream signaling pathways such as RAS-RAF-MEK-ERK-MPAK. By targeting specific signaling pathways, heterocyclic compounds have demonstrated efficacy in glioma therapeutics. Additionally, key kinases including phosphatidylinositol 3-kinase (PI3K), serine/threonine kinase, cytoplasmic tyrosine kinase (CTK), receptor tyrosine kinase (RTK) and lipid kinase (LK) have been considered for investigation. These pathways play crucial roles in drug effectiveness in glioma treatment. Heterocyclic compounds, encompassing pyrimidine, thiazole, quinazoline, imidazole, indole, acridone, triazine, and other derivatives, have shown promising results in targeting these pathways. As part of this review, we propose exploring novel structures with low toxicity and high potency for glioma treatment. The development of these compounds should strive to overcome multidrug resistance mechanisms and efficiently penetrate the blood-brain barrier. By optimizing the chemical properties and designing compounds with enhanced drug-like characteristics, we can maximize their therapeutic value and minimize adverse effects. Considering the complex nature of glioblastoma, these novel structures should be rigorously tested and evaluated for their efficacy and safety profiles.

Ibrutinib disrupts blood-tumor barrier integrity and prolongs survival in rodent glioma model

In malignant glioma, cytotoxic drugs are often inhibited from accessing the tumor site due to the blood-tumor barrier (BTB). Ibrutinib, FDA-approved lymphoma agent, inhibits Bruton tyrosine kinase (BTK) and has previously been shown to independently impair aortic endothelial adhesion and increase rodent glioma model survival in combination with cytotoxic therapy. Yet additional research is required to understand ibrutinib's effect on BTB function. In this study, we detail baseline BTK expression in glioma cells and its surrounding vasculature, then measure endothelial junctional expression/function changes with varied ibrutinib doses in vitro. Rat glioma cells and rodent glioma models were treated with ibrutinib alone (1-10 µM and 25 mg/kg) and in combination with doxil (10-100 µM and 3 mg/kg) to assess additive effects on viability, drug concentrations, tumor volume, endothelial junctional expression and survival. We found that ibrutinib, in a dose-dependent manner, decreased brain endothelial cell-cell adhesion over 24 h, without affecting endothelial cell viability (p < 0.005). Expression of tight junction gene and protein expression was decreased maximally 4 h after administration, along with inhibition of efflux transporter, ABCB1, activity. We demonstrated an additive effect of ibrutinib with doxil on rat glioma cells, as seen by a significant reduction in cell viability (p < 0.001) and increased CNS doxil concentration in the brain (56 ng/mL doxil alone vs. 74.6 ng/mL combination, p < 0.05). Finally, Ibrutinib, combined with doxil, prolonged median survival in rodent glioma models (27 vs. 16 days, p < 0.0001) with brain imaging showing a - 53% versus - 75% volume change with doxil alone versus combination therapy (p < 0.05). These findings indicate ibrutinib's ability to increase brain endothelial permeability via junctional disruption and efflux inhibition, to increase BTB drug entry and prolong rodent glioma model survival. Our results motivate the need to identify other BTB modifiers, all with the intent of improving survival and reducing systemic toxicities.

Reactivating PTEN to impair glioma stem cells by inhibiting cytosolic iron-sulfur assembly

Glioblastoma, the most lethal primary brain tumor, harbors glioma stem cells (GSCs) that not only initiate and maintain malignant phenotypes but also enhance therapeutic resistance. Although frequently mutated in glioblastomas, the function and regulation of PTEN in PTEN-intact GSCs are unknown. Here, we found that PTEN directly interacted with MMS19 and competitively disrupted MMS19-based cytosolic iron-sulfur (Fe-S) cluster assembly (CIA) machinery in differentiated glioma cells. PTEN was specifically succinated at cysteine (C) 211 in GSCs compared with matched differentiated glioma cells. Isotope tracing coupled with mass spectrometry analysis confirmed that fumarate, generated by adenylosuccinate lyase (ADSL) in the de novo purine synthesis pathway that is highly activated in GSCs, promoted PTEN C211 succination. This modification abrogated the interaction between PTEN and MMS19, reactivating the CIA machinery pathway in GSCs. Functionally, inhibiting PTEN C211 succination by reexpressing a PTEN C211S mutant, depleting ADSL by shRNAs, or consuming fumarate by the US Food and Drug Administration-approved prescription drug N-acetylcysteine (NAC) impaired GSC maintenance. Reexpressing PTEN C211S or treating with NAC sensitized GSC-derived brain tumors to temozolomide and irradiation, the standard-of-care treatments for patients with glioblastoma, by slowing CIA machinery-mediated DNA damage repair. These findings reveal an immediately practicable strategy to target GSCs to treat glioblastoma by combination therapy with repurposed NAC.

BMX deletion mitigates neuroinflammation induced by retinal ischemia/reperfusion through modulation of the AKT/ERK/STAT3 signaling cascade

Aims

Retinal ischemia/reperfusion (I/R) injury is implicated in the etiology of various ocular disorders. Prior research has demonstrated that bone marrow tyrosine kinase on chromosome X (BMX) contributes to the advancement of ischemic disease and inflammatory reactions. Consequently, the current investigation aims to evaluate BMX's impact on retinal I/R injury and clarify its implied mechanism of action.

Main methods

This study utilized male and female systemic BMX knockout (BMX-/-) mice to conduct experiments. The utilization of Western blot assay and immunofluorescence labeling techniques was employed to investigate variations in the expression of protein and tissue localization. Histomorphological changes were observed through H&E staining and SD-OCT examination. Visual function changes were assessed through electrophysiological experiments. Furthermore, apoptosis in the retina was identified using the TUNEL assay, as well as the ELISA technique, which has been utilized to determine the inflammatory factors level.

Key findings

Our investigation results revealed that the knockdown of BMX did not yield a significant effect on mouse retina. In mice, BMX knockdown mitigated the negative impact of I/R injury on retinal tissue structure and visual function. BMX knockdown effectively reduced apoptosis, suppressed inflammatory responses, and decreased inflammatory factors subsequent to I/R injury. The outcomes of the current investigation revealed that BMX knockdown partially protected the retina through downregulating phosphorylation of AKT/ERK/STAT3 pathway.

Significance

Our investigation showed that BMX-/- reduces AKT, ERK, and STAT3 phosphorylation, reducing apoptosis and inflammation. Thus, this strategy protected the retina from structural and functional damage after I/R injury.

Gliomas: a reflection of temporal gliogenic principles

The hijacking of early developmental programs is a canonical feature of gliomas where neoplastic cells resemble neurodevelopmental lineages and possess mechanisms of stem cell resilience. Given these parallels, uncovering how and when in developmental time gliomagenesis intersects with normal trajectories can greatly inform our understanding of tumor biology. Here, we review how elapsing time impacts the developmental principles of astrocyte (AS) and oligodendrocyte (OL) lineages, and how these same temporal programs are replicated, distorted, or circumvented in pathological settings such as gliomas. Additionally, we discuss how normal gliogenic processes can inform our understanding of the temporal progression of gliomagenesis, including when in developmental time gliomas originate, thrive, and can be pushed towards upon therapeutic coercion.

Stabilization of Pin1 by USP34 promotes Ubc9 isomerization and protein sumoylation in glioma stem cells

The peptidyl-prolyl cis-trans isomerase Pin1 is a pivotal therapeutic target in cancers, but the regulation of Pin1 protein stability is largely unknown. High Pin1 expression is associated with SUMO1-modified protein hypersumoylation in glioma stem cells (GSCs), but the underlying mechanisms remain elusive. Here we demonstrate that Pin1 is deubiquitinated and stabilized by USP34, which promotes isomerization of the sole SUMO E2 enzyme Ubc9, leading to SUMO1-modified hypersumoylation to support GSC maintenance. Pin1 interacts with USP34, a deubiquitinase with preferential expression and oncogenic function in GSCs. Such interaction is facilitated by Plk1-mediated phosphorylation of Pin1. Disruption of USP34 or inhibition of Plk1 promotes poly-ubiquitination and degradation of Pin1. Furthermore, Pin1 isomerizes Ubc9 to upregulate Ubc9 thioester formation with SUMO1, which requires CDK1-mediated phosphorylation of Ubc9. Combined inhibition of Pin1 and CDK1 with sulfopin and RO3306 most effectively suppresses orthotopic tumor growth. Our findings provide multiple molecular targets to induce Pin1 degradation and suppress hypersumoylation for cancer treatment.

The role of m6A-modified CircEPHB4 in glioma pathogenesis: Insights into cancer stemness metastasis

OBJECTIVE

While existing literature has provided insights into involvement of circEPHB4, SOX2 in glioma, their precise molecular mechanisms and synergistic implications in glioma pathogenesis still dim. This study aims to investigate significance and underlying mechanism of m6A-modified circEPHB4 in regulating SOX2/PHLDB2 axis in gliomas.

METHODS

The mRNA and protein expression were tested by qRT-PCR and Western blot, respectively. ChIP assay was performed to detect SOX2 enrichment on the PHLDB2 promoter. Cell sphere-forming assay to detect self-renewal ability, flow cytometry to determine positivity of CD133 expressions, Malignant behavior of glioma cells were detected by CCK-8, plate colony formation, scratch, and transwell assays. Glioma xenograft models were constructed to investigate effects of CircEPHB4 in tumor development in vivo.

RESULTS

Methyltransferase MELLT3 upregulated m6A modification of CircEPHB4, and YTHDC1 promoted cytoplasmic localization of m6A-modified CircEPHB4. Overexpression of wild-type CircEPHB4 enhanced glioma cells' stemness, metastasis, and proliferation. Cytoplasmic CircEPHB4 increased SOX2 mRNA stability by binding to IGF2BP2, and the effects observed by SOX2 knockdown were reversed by CircEPHB4 in glioma cells. SOX2 promoted transcriptional expression of PHLDB2 by enriching the PHLDB2 promoter region. SOX2 reversed the inhibition of PHLDB2 knockdown on stemness of glioma, cell proliferation, and metastasis. In vivo experiments also revealed that CircEPHB4 upregulated PHLDB2 expression by stabilizing SOX2 mRNA, which promoted in vivo tumor growth and accelerated stemness of glioma cells and metastasis.

CONCLUSION

This study reveals functional interaction and molecular mechanisms of m6A-modified circEPHB4 in regulating SOX2/PHLDB2 axis, highlighting their importance in glioma pathogenesis and potential as therapeutic targets.

Kunitz-type protease inhibitor TFPI2 remodels stemness and immunosuppressive tumor microenvironment in glioblastoma

Glioblastoma (GBM) tumors consist of multiple cell populations, including self-renewing glioblastoma stem cells (GSCs) and immunosuppressive microglia. Here we identified Kunitz-type protease inhibitor TFPI2 as a critical factor connecting these cell populations and their associated GBM hallmarks of stemness and immunosuppression. TFPI2 promotes GSC self-renewal and tumor growth via activation of the c-Jun N-terminal kinase-signal transducer and activator of transcription (STAT)3 pathway. Secreted TFPI2 interacts with its functional receptor CD51 on microglia to trigger the infiltration and immunosuppressive polarization of microglia through activation of STAT6 signaling. Inhibition of the TFPI2-CD51-STAT6 signaling axis activates T cells and synergizes with anti-PD1 therapy in GBM mouse models. In human GBM, TFPI2 correlates positively with stemness, microglia abundance, immunosuppression and poor prognosis. Our study identifies a function for TFPI2 and supports therapeutic targeting of TFPI2 as an effective strategy for GBM.

Repurposing Clemastine to Target Glioblastoma Cell Stemness

Brain tumor-initiating cells (BTICs) and tumor cell plasticity promote glioblastoma (GBM) progression. Here, we demonstrate that clemastine, an over-the-counter drug for treating hay fever and allergy symptoms, effectively attenuated the stemness and suppressed the propagation of primary BTIC cultures bearing PDGFRA amplification. These effects on BTICs were accompanied by altered gene expression profiling indicative of their more differentiated states, resonating with the activity of clemastine in promoting the differentiation of normal oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes. Functional assays for pharmacological targets of clemastine revealed that the Emopamil Binding Protein (EBP), an enzyme in the cholesterol biosynthesis pathway, is essential for BTIC propagation and a target that mediates the suppressive effects of clemastine. Finally, we showed that a neural stem cell-derived mouse glioma model displaying predominantly proneural features was similarly susceptible to clemastine treatment. Collectively, these results identify pathways essential for maintaining the stemness and progenitor features of GBMs, uncover BTIC dependency on EBP, and suggest that non-oncology, low-toxicity drugs with OPC differentiation-promoting activity can be repurposed to target GBM stemness and aid in their treatment.

CD44+ lung cancer stem cell-derived pericyte-like cells cause brain metastases through GPR124-enhanced trans-endothelial migration

Brain metastasis of lung cancer causes high mortality, but the exact mechanisms underlying the metastasis remain unclear. Here we report that vascular pericytes derived from CD44+ lung cancer stem cells (CSCs) in lung adenocarcinoma (ADC) potently cause brain metastases through the G-protein-coupled receptor 124 (GPR124)-enhanced trans-endothelial migration (TEM). CD44+ CSCs in perivascular niches generate the majority of vascular pericytes in lung ADC. CSC-derived pericyte-like cells (Cd-pericytes) exhibit remarkable TEM capacity to effectively intravasate into the vessel lumina, survive in the circulation, extravasate into the brain parenchyma, and then de-differentiate into tumorigenic CSCs to form metastases. Cd-pericytes uniquely express GPR124 that activates Wnt7-β-catenin signaling to enhance TEM capacity of Cd-pericytes for intravasation and extravasation, two critical steps during tumor metastasis. Furthermore, selective disruption of Cd-pericytes, GPR124, or the Wnt7-β-catenin signaling markedly reduces brain and liver metastases of lung ADC. Our findings uncover an unappreciated cellular and molecular paradigm driving tumor metastasis.

FIBP interacts with transcription factor STAT3 to induce EME1 expression and drive radioresistance in lung adenocarcinoma

Cancer cells inevitably develop radioresistance during lung adenocarcinoma radiotherapy. However, the mechanisms are incompletely clarified. In this study, we show that FIBP protein expression in lung adenocarcinoma tissues is upregulated and associated with worse overall survival. Functionally, we find that depletion of FIBP inhibits lung adenocarcinoma progression and radioresistance in vitro and in vivo. Moreover, we uncover that FIBP interacts with STAT3 to enhance its transcriptional activity, thereby inducing the expression of the downstream target gene EME1. Importantly, we demonstrate that the biological effects of FIBP are partially dependent on EME1 in lung adenocarcinoma. Our work reveals that FIBP modulates the STAT3/EME1 axis to drive lung cancer progression and radioresistance, indicating that targeting FIBP may be a novel intervention strategy for lung adenocarcinoma radiotherapy.

METTL3-mediated m6A modification of LINC00839 maintains glioma stem cells and radiation resistance by activating Wnt/β-catenin signaling

Long noncoding RNAs (lncRNAs) are involved in glioma initiation and progression. Glioma stem cells (GSCs) are essential for tumor initiation, maintenance, and therapeutic resistance. However, the biological functions and underlying mechanisms of lncRNAs in GSCs remain poorly understood. Here, we identified that LINC00839 was overexpressed in GSCs. A high level of LINC00839 was associated with GBM progression and radiation resistance. METTL3-mediated m6A modification on LINC00839 enhanced its expression in a YTHDF2-dependent manner. Mechanistically, LINC00839 functioned as a scaffold promoting c-Src-mediated phosphorylation of β-catenin, thereby inducing Wnt/β-catenin activation. Combinational use of celecoxib, an inhibitor of Wnt/β-catenin signaling, greatly sensitized GSCs to radiation. Taken together, our results showed that LINC00839, modified by METTL3-mediated m6A, exerts tumor progression and radiation resistance by activating Wnt/β-catenin signaling.

Glioma-derived small extracellular vesicles induce pericyte-phenotype transition of glioma stem cells under hypoxic conditions

BACKGROUND

Glioblastoma (GBM) is the most common and lethal primary brain tumor characterized by extensive vascularization. Anti-angiogenic therapy for this cancer offers the possibility of universal efficacy. However, preclinical and clinical studies suggest that anti-VEGF drug such as Bevacizumab actively promotes tumor invasion, which ultimately leads to a therapy-resistant and recurrent phenotype of GBMs. Whether Bevacizumab can improve survival over chemotherapy alone remains debated. Herein, we emphasized the importance of small extracellular vesicles (sEVs) internalization by glioma stem cells (GSCs) in giving rise to the failure of anti-angiogenic therapy in the treatment of GBMs and discovered a specific therapeutic target for this damaging disease.

METHODS

To experimentally prove that hypoxia condition promotes the release of GBM cells-derived sEVs, which could be taken up by the surrounding GSCs, we used an ultracentrifugation strategy to isolate GBM-derived sEVs under hypoxic or normoxic conditions, performed bioinformatics analysis and multidimensional molecular biology experiments, and established a xenograft mouse model.

RESULTS

The internalization of sEVs by GSCs was proved to promote tumor growth and angiogenesis through the pericyte-phenotype transition. Hypoxia-derived sEVs could efficiently deliver TGF-β1 to GSCs, thus resulting in the activation of the TGF-β signaling pathway and the consequent pericyte-phenotype transition. Specifically targeting GSC-derived pericyte using Ibrutinib can reverse the effects of GBM-derived sEVs and enhance the tumor-eradicating effects when combined with Bevacizumab.

CONCLUSION

This present study provides a new interpretation of the failure of anti-angiogenic therapy in the non-operative treatment of GBMs and discovers a promising therapeutic target for this intractable disease.

Xihuang Pill-destabilized CD133/EGFR/Akt/mTOR cascade reduces stemness enrichment of glioblastoma via the down-regulation of SOX2

BACKGROUND

Our previous study found that XHP could induce GBM cells to undergo apoptosis. A lot of evidence suggests that glioma stem-like cells (GSCs) are key factors that contribute to disease progression and poor prognosis of glioblastoma multiforme (GBM). Traditional Chinese medicine has been applied in clinical practice as a complementary and alternative therapy for glioma.

PURPOSE

To evaluate the effect and the potential molecular mechanism of Xihuang pill (XHP) on GSCs.

METHODS

UPLC-QTOF-MS analysis was used for constituent analysis of XHP. Using network pharmacology and bioinformatics methods, a molecular network targeting GSCs by the active ingredients in XHP was constructed. Cell viability, self-renewal ability, apoptosis, and GSC markers were detected by CCK-8 assay, tumor sphere formation assay and flow cytometry, respectively. The interrelationship between GSC markers (CD133 and SOX2) and key proteins of the EGFR/Akt/mTOR signaling pathway was evaluated using GEPIA and verified by western blot. A GBM cell line stably overexpressing Akt was constructed using lentivirus to evaluate the role of Akt signaling in the regulation of glioma stemness. The effect of XHP on glioma growth was analyzed by a subcutaneously transplanted glioma cell model in nude mice, hematoxylin-eosin staining was used to examine pathological changes, TUNEL staining was used to detect apoptosis in tumor tissues, and the expression of GSC markers in tumor tissues was identified by western blot and immunofluorescence.

RESULTS

Bioinformatics analysis showed that 55 matched targets were related to XHP targets and glioma stem cell targets. In addition to causing apoptosis, XHP could diminish the number of GBM 3D spheroids, the proportion of CD133-positive cells and the expression level of GSC markers (CD133 and SOX2) in vitro. Furthermore, XHP could attenuate the expression of CD133, EGFR, p-Akt, p-mTOR and SOX2 in GBM spheres. Overexpression of Akt significantly increased the expression level of SOX2, which was prohibited in the presence of XHP. XHP reduced GSC markers including CD133 and SOX2, and impeded the development of glioma growth in xenograft mouse models in vivo.

CONCLUSION

We demonstrate for the first time that XHP down-regulates stemness, restrains self-renewal and induces apoptosis in GSCs and impedes glioma growth by down-regulating SOX2 through destabilizing the CD133/EGFR/Akt/mTOR cascade.

Sitagliptin inhibits the survival, stemness and autophagy of glioma cells, and enhances temozolomide cytotoxicity

The standard regimen treatment has improved GBM outcomes, but the survival rate of patients is still unsatisfactory. Temozolomide (TMZ) resistance is one of main reasons limiting the therapeutic efficacy of GBM. However, there are currently no TMZ-sensitizing drugs available in the clinic. Here we aimed to study whether the antidiabetic drug Sitagliptin can inhibit the survival, stemness and autophagy of GBM cells, and thus enhance TMZ cytotoxicity. We used CCK-8, EdU, colony formation, TUNEL and flow cytometry assays to assess cell proliferation and apoptosis; sphere formation and limiting dilution assays to measure self-renewal and stemness of glioma stem cells (GSCs); Western blot, qRT-PCR or immunohistochemical analysis to measure the expression of proliferation or stem cell markers; Western blot/fluorescent analysis of LC3 and other molecules to evaluate autophagy formation and degradation in glioma cells. We found that Sitagliptin inhibited proliferation and induced apoptosis in GBM cells and suppressed self-renewal and stemness of GSCs. The in vitro findings were further confirmed in glioma intracranial xenograft models. Sitagliptin administration prolonged the survival time of tumor-bearing mice. Sitagliptin could inhibit TMZ-induced protective autophagy and enhance the cytotoxicity of TMZ in glioma cells. In addition, Sitagliptin acted as a dipeptidyl peptidase 4 inhibitor in glioma as well as in diabetes, but it did not affect the blood glucose level and body weight of mice. These findings suggest that Sitagliptin with established pharmacologic and safety profiles could be repurposed as an antiglioma drug to overcome TMZ resistance, providing a new option for GBM therapy.

Radiation-Induced Bystander Effect on the Genome of Bone Marrow Mesenchymal Stem Cells in Lung Cancer

Aims: Radiation by-radiation effect (RIBE) can induce the genomic instability of bone marrow mesenchymal stem cells (BMSCs) adjacent to lung cancer, and this effect not only exists in the short-term, but also accompanies it in the long-term, but its specific mechanism is not clear. Our goal is to explore the similarities and differences in the mechanism of genomic damage in tumor-associated BMSCs induced by short-term and long-term RIBE, and to provide a theoretical basis for adjuvant drugs for protection against RIBE at different clinical time periods. Results: We found that both short- and long-term RIBE induced genomic instability. We could show a high expression of TGF-β1, TNF-α, and HIF-1α in tumor-associated BMSCs after short-term RIBE whereas only TNF-α and HIF-1α expression was increased in long-term RIBE. We further confirmed that genomic instability is associated with the activation of the HIF-1α pathway and that this is mediated by TNF-α and TGF-β1. In addition, we found differences in the mechanisms of genomic instability in the considered RIBE windows of analysis. In short-term RIBE, both TNF-α and TGF-β1 play a role, whereas only TNF-α plays a decisive role in long-term RIBE. In addition, there were differences in BMSC recruitment and genomic instability of different tissues with a more pronounced expression in tumor and bone marrow than compared to lung. Innovation and Conclusion: We could show dynamic changes in the expression of the cytokines TGF-β1 and TNF-α during short- and long-term RIBE. The differential expression of the two is the key to causing the genomic damage of tumor-associated BMSCs in the considered windows of analysis. Therefore, these results may serve as a guideline for the administration of radiation protection adjuvant drugs at different clinical stages. Antioxid. Redox Signal. 38, 747-767.

Anticancer effect of zanubrutinib in HER2-positive breast cancer cell lines

Small molecule Bruton's tyrosine kinase (BTK) inhibitors have been developed for the treatment of various haemato-oncological diseases, and ibrutinib was approved as the first BTK inhibitor for anticancer therapy in 2013. Previous reports proved the receptor kinase human epidermal growth factor receptor 2 (HER2) to be a valid off-target kinase of ibrutinib and potentially other irreversible BTK inhibitors, as it possesses a druggable cysteine residue in the active site of the enzyme. These findings suggest ibrutinib as a candidate drug for repositioning in HER2-positive breast cancer (BCa). This subtype of breast cancer belongs to one of the most common classes of breast tumours, and its prognosis is characterized by a high rate of recurrence and tumour invasiveness. Based on their similar kinase selectivity profiles, we investigated the anticancer effect of zanubrutinib, evobrutinib, tirabrutinib and acalabrutinib in different BCa cell lines and sought to determine whether it is linked with targeting the epidermal growth factor receptor family (ERBB) pathway. We found that zanubrutinib is a potential inhibitor of the HER2 signalling pathway, displaying an antiproliferative effect in HER2-positive BCa cell lines. Zanubrutinib effectively inhibits the phosphorylation of proteins in the ERBB signalling cascade, including the downstream kinases Akt and ERK, which mediate key signals ensuring the survival and proliferation of cancer cells. We thus propose zanubrutinib as another suitable candidate for repurposing in HER2-amplified solid tumours.

SERPINF1 Mediates Tumor Progression and Stemness in Glioma

Serpin family F member 1 (SERPINF1) reportedly plays multiple roles in various tumors; however, its clinical significance and molecular functions in glioma have been largely understudied. In the present study, we analyzed the prognostic value of SERPINF1 in three independent glioma datasets. Next, we explored the molecular functions and transcriptional regulation of SERPINF1 at the single-cell level. Moreover, in vitro experiments were conducted to evaluate the roles of SERPINF1 in the proliferation, invasion, migration, and stemness of glioma cells. Our results showed that a higher expression of SERPINF1 correlated with a poor overall survival rate in glioma patients (hazard ratio: 4.061 in TCGA, 2.017 in CGGA, and 1.675 in GSE16011, p < 0.001). Besides, SERPINF1 knockdown could suppress the proliferation, invasion, and migration of glioma cells in vitro. In addition, SERPINF1 expression was significantly upregulated in glioma stem cells (GSCs) compared to parental glioma cells. Knocking down SERPINF1 impaired the sphere formation of GSC-A172 and GSC-LN18. Bioinformatics analysis revealed that Notch signaling activation was closely associated with high SERPINF1 expression at the single-cell level. Furthermore, STAT1, CREM, and NR2F2 may participate in the transcriptional regulation of SERPINF1 in glioma. Overall, our results suggest that SERPINF1 may be a candidate prognostic predictor and potential therapeutic target for glioma.

M2 tumor-associated macrophage mediates the maintenance of stemness to promote cisplatin resistance by secreting TGF-β1 in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a deadly gastrointestinal malignancy, and chemotherapy resistance is a key factor leading to its poor prognosis. M2 tumor-associated macrophages (M2-TAMs) may be an important cause of chemoresistance in ESCC, but its exact mechanism is still unclear.

METHODS

In order to study the role of M2-TAMs in ESCC chemoresistance, CCK-8, clone formation assay, flow cytometric apoptosis assay, qRT-PCR, western blotting, and serum-free sphere formation assays were used. In vivo animal experiments and human ESCC tissues were used to confirm the findings.

RESULTS

In vitro and in vivo animal experiments, M2-TAMs reduced the sensitivity of ESCC cells to cisplatin. Mechanistically, M2-TAMs highly secreted TGF-β1 which activated the TGFβR1-smad2/3 pathway to promote and maintain the stemness characteristic of ESCC cells, which could inhibit the sensitivity to cisplatin. Using TGFβ signaling inhibitor SB431542 or knockdown of TGFβR1 could reverse the cisplatin resistance of ESCC cells. In 92 cases of human ESCC tissues, individuals with a high density of M2-TAMs had considerably higher levels of TGF-β1. These patients also had worse prognoses and richer stemness markers.

CONCLUSION

TGF-β1 secreted from M2-TAMs promoted and maintained the stemness characteristic to induce cisplatin resistance in ESCC by activating the TGFβ1-Smad2/3 pathway.

Cancer-associated fibroblasts induce growth and radioresistance of breast cancer cells through paracrine IL-6

In breast cancer, the most numerous stromal cells are cancer-associated fibroblasts (CAFs), which are associated with disease progression and chemoresistance. However, few studies have explored the function of CAFs in breast cancer cell radiosensitivity. Here, CAF-derived conditioned media was observed to induce breast cancer cell growth and radioresistance. CAFs secrete interleukin 6 (IL-6) which activates signal transducer and activator of transcription 3 (STAT3) signaling pathway, thus promoting the growth and radioresistance of breast cancer cells. Treatment with an inhibitor of STAT3 or an IL-6 neutralizing antibody blocked the growth and radioresistance induced by CAFs. In in vivo mouse models, tocilizumab (an IL-6 receptor monoclonal antibody) abrogated CAF-induced growth and radioresistance. Moreover, in breast cancer, a poor response to radiotherapy was associated with IL-6 and p-STAT3 expression. These results indicated that IL-6 mediates cross-talk between breast cancer cells and CAFs in the tumor microenvironment. Our results identified the IL-6/STAT3 signaling pathway as an important therapeutic target in breast cancer radiotherapy.

PTN-PTPRZ1 signaling axis blocking mediates tumor microenvironment remodeling for enhanced glioblastoma treatment

Glioblastoma (GBM) is a malignant brain tumor with a poor prognosis that is highly heterogeneous and invasive. One of the most major challenges of GBM treatment in the clinic is the blood-brain barrier (BBB). Additionally, the tumor microenvironment (TME) is highly enriched with immunosuppressed M2-like tumor-associated macrophages (M2 TAMs) and glioblastoma stem cells (GSCs), which promoted the malignancy of GBM through the PTN-PTPRZ1 signaling axis. Here, we developed a self-assembled dual-targeted hybrid micelle (DT-GM1) as a nanocarrier to deliver the chemotherapeutic agent doxorubicin (DOX). We demonstrated that this DT-GM1/DOX can cross the BBB using in vitro and in vivo GBM models, and that M2pep and PTPRZ1 antibodies allow it to precisely target the tumor microenvironment where M2 TAMs and GSCs are enriched, increasing intracellular drug accumulation via multiple internalization pathways. Additionally, simultaneous elimination of M2 TAMs and GSCs blocked the PTN-PTPRZ1 signaling axis, resulting in less M2 TAM infiltration and increased polarization to the M1 phenotype, reshaping the immune microenvironment. Overall, we have established a nanocarrier that can penetrate the BBB and target the TME while also synergizing with GBM chemotherapeutic agents, providing a promising new strategy for GBM treatment.

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

OBJECTIVE

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

MATERIAL AND METHOD

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

RESULTS

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

CONCLUSION

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

Roles of STAT3 in the pathogenesis and treatment of glioblastoma

Glioblastoma (GBM) is the most malignant of astrocytomas mainly involving the cerebral hemispheres and the cerebral cortex. It is one of the fatal and refractory solid tumors, with a 5-year survival rate of merely 5% among the adults. IL6/JAK/STAT3 is an important signaling pathway involved in the pathogenesis and progression of GBM. The expression of STAT3 in GBM tissues is substantially higher than that of normal brain cells. The abnormal activation of STAT3 renders the tumor microenvironment of GBM immunosuppression. Besides, blocking the STAT3 pathway can effectively inhibit the growth and metastasis of GBM. On this basis, inhibition of STAT3 may be a new therapeutic approach for GBM, and the combination of STAT3 targeted therapy and conventional therapies may improve the current status of GBM treatment. This review summarized the roles of STAT3 in the pathogenesis of GBM and the feasibility of STAT3 for GBM target therapy.

Co-delivery of ibrutinib and hydroxychloroquine by albumin nanoparticles for enhanced chemotherapy of glioma

Ibrutinib (IBR) is an oral covalent inhibitor of Bruton's tyrosine kinase (BTK) that has been approved for the treatment of hematological malignancies. It was reported that IBR exhibited great therapeutic potential for glioma. However, the poor water solubility and high hepatic first-pass effect restrict its anti-glioma application. Meanwhile, IBR induces cytoprotective autophagy through Akt/mTOR signaling pathway, thus leading to a compromised antitumor effect. Herein, we aimed to develop a human serum albumin (HSA) based co-delivery system (IBR&HCQ HSA NPs) encapsulating IBR and hydroxychloroquine (HCQ). The bioavailability of IBR was largely improved, and enhanced sensitivity of glioma to IBR was achieved due to inhibition effect of HCQ on IBR-induced pro-survival autophagy. The physicochemical properties of IBR&HCQ HSA NPs were characterized to optimize the formulation. Biodistribution investigation revealed that HSA NPs (20 mg/kg, i.v.) dramatically increased the accumulation of IBR in glioma, which was 5.59 times higher than that of free IBR (100 mg/kg, i.g.). CCK-8 and apoptosis assays demonstrated that IBR&HCQ HSA NPs showed maximal cytotoxicity to C6 cells. In vivo studies indicated that the survival time was significantly prolonged in IBR&HCQ HSA NPs treated mice compared to those treated with IBR HSA NPs. Taken together, the HSA-based drug delivery system of IBR and HCQ opens a new avenue for efficient treatment of glioma.

Transcription factor NFE2L3 promotes the proliferation of esophageal squamous cell carcinoma cells and causes radiotherapy resistance by regulating IL-6

OBJECTIVE

To scrutinize the impact of overexpression and interference of NFE2L3 on radiosensitivity of esophageal squamous cell carcinoma cells (ESCC) and its downstream mechanism and to assess whether NFE2L3 expression alters in vivo radiosensitivity of ESCC by developing a subcutaneous tumor model in mice.

METHODS

Through RNA-Seq, we compared the differentially expressed genes between the ECA-109R cell line and its parent ECA-109 cell line. The differentially expressed genes were selected and verified by qRT-PCR. Transfection of ESCC cell lines with NFE2L3 inhibitor or mimic lentivirus constructs was done to study the activity of NFE2L3. To assess the effect of NFE2L3 on cellular growth and proliferation, clonogenic survival assay, EdU incorporation assay, and CCK-8 assay were done after irradiation. To probe how many irradiated DNA double-strand breaks were produced, the corresponding intensity of γ-H2AX foci were detected by immunofluorescence. Apoptotic cells were assayed by flow cytometry assay after irradiation; To investigate the downstream genes of NFE2L3, we knocked NFE2L3, and RNA-Seq was used to find out the downstream genes. qRT-PCR and western blot ensued to score associated protein profiles. The in vivo ESCC cell radiosensitivity was scrutinized by nude mouse xenograft models.

RESULTS

The differential genes between ECA-109R cells and its parent ECA-109 cells were compared by qRT-PCR to unveil a significant increase in NFE2L3 expression. Functional analysis indicated that NFE2L3 increased radioresistance in ESCC cells. Then, through high-throughput sequencing and bioinformatics analysis, IL-6 was found to be a hub gene that played a role downstream of NFE2L3 and was verified by qRT-PCR, western blot, and double luciferase reporter gene experiment. NFE2L3 could regulate ESCC cell radiosensitivity via the IL-6-STAT3 signaling pathway, and downregulation of IL-6 expression could reverse the effects of highly expressed NFE2L3. In vivo tumor xenograft experiments confirmed that NFE2L3 affects the sensitivity to radiation therapy.

CONCLUSION

NFE2L3 can affect the radiosensitivity of ESCC cells through IL-6 transcription and IL-6/STAT3 signaling pathway. This makes NFE2L3 a putative target to regulate ESCC cell radiosensitivity.

Current progress of nanomedicine for prostate cancer diagnosis and treatment

Prostate cancer (PCa) is the most common new cancer case and the second most fatal malignancy in men. Surgery, endocrine therapy, radiotherapy and chemotherapy are the main clinical treatment options for PCa. However, most prostate cancers can develop into castration-resistant prostate cancer (CRPC), and due to the invasiveness of prostate cancer cells, they become resistant to different treatments and activate tumor-promoting signaling pathways, thereby inducing chemoresistance, radioresistance, ADT resistance, and immune resistance. Nanotechnology, which can combine treatment with diagnostic imaging tools, is emerging as a promising treatment modality in prostate cancer therapy. Nanoparticles can not only promote their accumulation at the pathological site through passive targeting techniques for enhanced permeability and retention (EPR), but also provide additional advantages for active targeting using different ligands. This property results in a reduced drug dose to achieve the desired effect, a longer duration of action within the tumor and fewer side effects on healthy tissues. In addition, nanotechnology can create good synergy with radiotherapy, chemotherapy, thermotherapy, photodynamic therapy and gene therapy to enhance their therapeutic effects with greater scope, and reduce the resistance of prostate cancer. In this article, we intend to review and discuss the latest technologies regarding the use of nanomaterials as therapeutic and diagnostic tools for prostate cancer.

The Interplay of Tumor Vessels and Immune Cells Affects Immunotherapy of Glioblastoma

Immunotherapies with immune checkpoint inhibitors or adoptive cell transfer have become powerful tools to treat cancer. These treatments act via overcoming or alleviating tumor-induced immunosuppression, thereby enabling effective tumor clearance. Glioblastoma (GBM) represents the most aggressive, primary brain tumor that remains refractory to the benefits of immunotherapy. The immunosuppressive immune tumor microenvironment (TME), genetic and cellular heterogeneity, and disorganized vasculature hinder drug delivery and block effector immune cell trafficking and activation, consequently rendering immunotherapy ineffective. Within the TME, the mutual interactions between tumor, immune and endothelial cells result in the generation of positive feedback loops, which intensify immunosuppression and support tumor progression. We focus here on the role of aberrant tumor vasculature and how it can mediate hypoxia and immunosuppression. We discuss how immune cells use immunosuppressive signaling for tumor progression and contribute to the development of resistance to immunotherapy. Finally, we assess how a positive feedback loop between vascular normalization and immune cells, including myeloid cells, could be targeted by combinatorial therapies with immune checkpoint blockers and sensitize the tumor to immunotherapy.

The E3 ubiquitin ligase HUWE1 acts through the N-Myc-DLL1-NOTCH1 signaling axis to suppress glioblastoma progression

BACKGROUND

Elucidation of the post-transcriptional modification has led to novel strategies to treat intractable tumors, especially glioblastoma (GBM). The ubiquitin-proteasome system (UPS) mediates a reversible, stringent and stepwise post-translational modification which is closely associated with malignant processes of GBM. To this end, developing novel therapeutic approaches to target the UPS may contribute to the treatment of this disease. This study aimed to screen the vital and aberrantly regulated component of the UPS in GBM. Based on the molecular identification, functional characterization, and mechanism investigation, we sought to elaborate a novel therapeutic strategy to target this vital factor to combat GBM.

METHODS

We combined glioma datasets and human patient samples to screen and identify aberrantly regulated E3 ubiquitin ligase. Multidimensional database analysis and molecular and functional experiments in vivo and in vitro were used to evaluate the roles of HECT, UBA and WWE domain-containing E3 ubiquitin ligase 1 (HUWE1) in GBM. dCas9 synergistic activation mediator system and recombinant adeno-associated virus (rAAV) were used to endogenously overexpress full-length HUWE1 in vitro and in glioma orthotopic xenografts.

RESULTS

Low expression of HUWE1 was closely associated with worse prognosis of GBM patients. The ubiquitination and subsequent degradation of N-Myc mediated by HUWE1, leading to the inactivation of downstream Delta-like 1 (DLL1)-NOTCH1 signaling pathways, inhibited the proliferation, invasion, and migration of GBM cells in vitro and in vivo. A rAAV dual-vector system for packaging and delivery of dCas9-VP64 was used to augment endogenous HUWE1 expression in vivo and showed an antitumor activity in glioma orthotopic xenografts.

CONCLUSIONS

The E3 ubiquitin ligase HUWE1 acts through the N-Myc-DLL1-NOTCH1 signaling axis to suppress GBM progression. Antitumor activity of rAAV dual-vector delivering dCas9-HUWE1 system uncovers a promising therapeutic strategy for GBM.

Effects of STAT3 Inhibitor BP-1-102 on The Proliferation, Invasiveness, Apoptosis and Neurosphere Formation of Glioma Cells in Vitro

Malignant glioma, especially glioblastoma (GBM), has historically been associated with a low survival rate. The hyperactivation of STAT3 played a key role in GBM initiation and resistance to therapy; thus, there is an urgent requirement for novel STAT3 inhibitors. BP-1-102 was recently reported as a biochemical inhibitor of STAT3, but its roles and mechanism in biological behavior of glioma cells were still unclear. In this study, the effects of BP-1-102 on proliferation, apoptosis, invasion and neurosphere formation of glioma cell were investigated. Our results indicated that BP-1-102 inhibited the proliferation of U251 and A172 cells, and their IC50 values were 10.51 and 8.534 μM, respectively. Furthermore, BP-1-102 inhibited the invasion and migration abilities of U251 and A172 cells by decreasing the expression of matrix metallopeptidase 9, and induced glioma cell apoptosis by decreasing the expression of B-cell lymphoma-2. BP-1-102 also inhibited the formation of neurosphere. Mechanically, BP-1-102 reduced the phosphorylation of STAT3 and the p-STAT3's nuclear translocation in glioma cells. Thus, this study herein provided a potential drug for glioma therapy.

Molecular Pathways and Genomic Landscape of Glioblastoma Stem Cells: Opportunities for Targeted Therapy

Glioblastoma (GBM) is an aggressive tumor of the central nervous system categorized by the World Health Organization as a Grade 4 astrocytoma. Despite treatment with surgical resection, adjuvant chemotherapy, and radiation therapy, outcomes remain poor, with a median survival of only 14-16 months. Although tumor regression is often observed initially after treatment, long-term recurrence or progression invariably occurs. Tumor growth, invasion, and recurrence is mediated by a unique population of glioblastoma stem cells (GSCs). Their high mutation rate and dysregulated transcriptional landscape augment their resistance to conventional chemotherapy and radiation therapy, explaining the poor outcomes observed in patients. Consequently, GSCs have emerged as targets of interest in new treatment paradigms. Here, we review the unique properties of GSCs, including their interactions with the hypoxic microenvironment that drives their proliferation. We discuss vital signaling pathways in GSCs that mediate stemness, self-renewal, proliferation, and invasion, including the Notch, epidermal growth factor receptor, phosphatidylinositol 3-kinase/Akt, sonic hedgehog, transforming growth factor beta, Wnt, signal transducer and activator of transcription 3, and inhibitors of differentiation pathways. We also review epigenomic changes in GSCs that influence their transcriptional state, including DNA methylation, histone methylation and acetylation, and miRNA expression. The constituent molecular components of the signaling pathways and epigenomic regulators represent potential sites for targeted therapy, and representative examples of inhibitory molecules and pharmaceuticals are discussed. Continued investigation into the molecular pathways of GSCs and candidate therapeutics is needed to discover new effective treatments for GBM and improve survival.

Drug Repurposing, a Fast-Track Approach to Develop Effective Treatments for Glioblastoma

Glioblastoma (GBM) remains one of the most difficult tumors to treat. The mean overall survival rate of 15 months and the 5-year survival rate of 5% have not significantly changed for almost 2 decades. Despite progress in understanding the pathophysiology of the disease, no new effective treatments to combine with radiation therapy after surgical tumor debulking have become available since the introduction of temozolomide in 1999. One of the main reasons for this is the scarcity of compounds that cross the blood-brain barrier (BBB) and reach the brain tumor tissue in therapeutically effective concentrations. In this review, we focus on the role of the BBB and its importance in developing brain tumor treatments. Moreover, we discuss drug repurposing, a drug discovery approach to identify potential effective candidates with optimal pharmacokinetic profiles for central nervous system (CNS) penetration and that allows rapid implementation in clinical trials. Additionally, we provide an overview of repurposed candidate drug currently being investigated in GBM at the preclinical and clinical levels. Finally, we highlight the importance of phase 0 trials to confirm tumor drug exposure and we discuss emerging drug delivery technologies as an alternative route to maximize therapeutic efficacy of repurposed candidate drug.

The Network of Tumor Microtubes: An Improperly Reactivated Neural Cell Network With Stemness Feature for Resistance and Recurrence in Gliomas

Gliomas are known as an incurable brain tumor for the poor prognosis and robust recurrence. In recent years, a cellular subpopulation with tumor microtubes (TMs) was identified in brain tumors, which may provide a new angle to explain the invasion, resistance, recurrence, and heterogeneity of gliomas. Recently, it was demonstrated that the cell subpopulation also expresses neural stem cell markers and shares a lot of features with both immature neurons and cancer stem cells and may be seen as an improperly reactivated neural cell network with a stemness feature at later time points of life. TMs may also provide a new angle to understand the resistance and recurrence mechanisms of glioma stem cells. In this review, we innovatively focus on the common features between TMs and sprouting axons in morphology, formation, and function. Additionally, we summarized the recent progress in the resistance and recurrence mechanisms of gliomas with TMs and explained the incurability and heterogeneity in gliomas with TMs. Moreover, we discussed the recently discovered overlap between cancer stem cells and TM-positive glioma cells, which may contribute to the understanding of resistant glioma cell subpopulation and the exploration of the new potential therapeutic target for gliomas.

Dicer deficiency impairs proliferation but potentiates anti-tumoral effect of macrophages in glioblastoma

Glioblastoma is a lethal primary brain tumor with abundant immune-suppressive glioblastoma-associated macrophage (GAM) infiltration. Skewing immune suppressive GAMs towards an immune-activating phenotype represents a promising immunotherapeutic strategy against glioblastoma. Herein, we reported that genetic deletion of miRNA-processing enzyme Dicer in macrophages inhibited the growth of GL261 murine glioblastoma xenografts and prolonged survival of tumor-bearing mice. Single cell RNA sequencing (scRNA-seq) of the tumor-infiltrating immune cells revealed that Dicer deletion in macrophages reduced the proportion of cell-cycling GAM cluster and reprogramed the remaining GAMs towards a proinflammatory activation state (enhanced phagocytotic and IFN-producing signature). Dicer-deficient GAMs showed reduced level of cyclin-dependent kinases (CDK1 and CDK2) and increased expression of CDK inhibitor p27 Kip1, thus manifesting impaired proliferation. Dicer knockout enhanced phagocytotic activity of GAMs to eliminate GL261 tumor cells. Increased proinflammatory GAM clusters in macrophage Dicer-deficient mice actively interacted with tumor-infiltrating T cells and NK cells through TNF paracrine signaling to create a pro-inflammatory immune microenvironment for tumor cell elimination. Our work identifies the role of Dicer deletion in macrophages in generating an immune-activating microenvironment, which could be further developed as a potential immunotherapeutic strategy against glioblastoma.

Targeting Glioblastoma Stem Cells to Overcome Chemoresistance: An Overview of Current Therapeutic Strategies

Glioblastoma (GBM) is the most malignant primary brain tumor. The current standard approach in GBM is surgery, followed by treatment with radiation and temozolomide (TMZ); however, GBM is highly resistant to current therapies, and the standard of care has not been revised over the last two decades, indicating an unmet need for new therapies. GBM stem cells (GSCs) are a major cause of chemoresistance due to their ability to confer heterogeneity and tumorigenic capacity. To improve patient outcomes and survival, it is necessary to understand the properties and mechanisms underlying GSC chemoresistance. In this review, we describe the current knowledge on various resistance mechanisms of GBM to therapeutic agents, with a special focus on TMZ, and summarize the recent findings on the intrinsic and extrinsic mechanisms of chemoresistance in GSCs. We also discuss novel therapeutic strategies, including molecular targeting, autophagy inhibition, oncolytic viral therapy, drug repositioning, and targeting of GSC niches, to eliminate GSCs, from basic research findings to ongoing clinical trials. Although the development of effective therapies for GBM is still challenging, this review provides a better understanding of GSCs and offers future directions for successful GBM therapy.

Expression Modulation of Immune Checkpoint Molecules by Ibrutinib and Everolimus Through STAT3 in MCF-7 Breast Cancer Cells

Tumor-targeted therapy with small-molecule inhibitors (SMIs) has been demonstrated to be a highly effective therapeutic strategy for various cancers. However, their possible associations with immune evasion mechanisms remain unknown. This study examined the association of inhibitors of the protein kinase B (AKT), mammalian target of rapamycin (mTOR), and Bruton’s tyrosine kinase (BTK) signaling pathways with the expression of immune checkpoint ligands programmed death-ligand 1 (PD-L1), CD155, and galectin-9 (Gal-9) in a breast cancer cell line. MCF-7 cells were treated with everolimus, MK-2206, and ibrutinib. An MTT assay was used to determine the optimal dose for all drugs. A real-time polymerase chain reaction was utilized to measure the mRNA expression of PD-L1, CD155, and Gal-9. The western blot technique was also employed to evaluate the protein expression of the phosphorylated signal transducer and activator of transcription 3 (STAT3). The optimal doses of everolimus, MK-2206, and ibrutinib were observed to be 200, 320, and 2000 nM, respectively. The PD-L1 and CD155 mRNA expression was significantly decreased following the treatment with everolimus and ibrutinib, but not with MK-2206. There were no differences in Gal-9 expression between the single-treated and control groups; however, combined treatment with everolimus and ibrutinib increased its mRNA expression. Everolimus and ibrutinib both inhibited constitutive STAT3 phosphorylation in MCF-7, which was more pronounced in combination treatment. The findings regarding the modulation of PD-L1, CD155, and Gal-9 molecules by SMIs emphasize the crosstalk between the expression of these immune checkpoint molecules and AKT/mTOR/BTK signaling pathways through STAT3 as a critical transcription factor.

Evolving Insights Into the Biological Function and Clinical Significance of Long Noncoding RNA in Glioblastoma

Glioblastoma (GBM) is one of the most prevalent and aggressive cancers worldwide. The overall survival period of GBM patients is only 15 months even with standard combination therapy. The absence of validated biomarkers for early diagnosis mainly accounts for worse clinical outcomes of GBM patients. Thus, there is an urgent requirement to characterize more biomarkers for the early diagnosis of GBM patients. In addition, the detailed molecular basis during GBM pathogenesis and oncogenesis is not fully understood, highlighting that it is of great significance to elucidate the molecular mechanisms of GBM initiation and development. Recently, accumulated pieces of evidence have revealed the central roles of long noncoding RNAs (lncRNAs) in the tumorigenesis and progression of GBM by binding with DNA, RNA, or protein. Targeting those oncogenic lncRNAs in GBM may be promising to develop more effective therapeutics. Furthermore, a better understanding of the biological function and underlying molecular basis of dysregulated lncRNAs in GBM initiation and development will offer new insights into GBM early diagnosis and develop novel treatments for GBM patients. Herein, this review builds on previous studies to summarize the dysregulated lncRNAs in GBM and their unique biological functions during GBM tumorigenesis and progression. In addition, new insights and challenges of lncRNA-based diagnostic and therapeutic potentials for GBM patients were also introduced.

Ibrutinib Inhibits BMX-Dependent Endothelial VCAM-1 Expression In Vitro and Pro-Atherosclerotic Endothelial Activation and Platelet Adhesion In Vivo

Introduction

Inflammatory activation of the vascular endothelium leads to overexpression of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), contributing to the pro-thrombotic state underpinning atherogenesis. While the role of TEC family kinases (TFKs) in mediating inflammatory cell and platelet activation is well defined, the role of TFKs in vascular endothelial activation remains unclear. We investigated the role of TFKs in endothelial cell activation in vitro and in a nonhuman primate model of diet-induced atherosclerosis in vivo.

Methods and Results

In vitro, we found that ibrutinib blocked activation of the TFK member, BMX, by vascular endothelial growth factors (VEGF)-A in human aortic endothelial cells (HAECs). Blockade of BMX activation with ibrutinib or pharmacologically distinct BMX inhibitors eliminated the ability of VEGF-A to stimulate VCAM-1 expression in HAECs. We validated that treatment with ibrutinib inhibited TFK-mediated platelet activation and aggregation in both human and primate samples as measured using flow cytometry and light transmission aggregometry. We utilized contrast-enhanced ultrasound molecular imaging to measure platelet GPIbα and endothelial VCAM-1 expression in atherosclerosis-prone carotid arteries of obese nonhuman primates. We observed that the TFK inhibitor, ibrutinib, inhibited platelet deposition and endothelial cell activation in vivo.

Conclusion

Herein we found that VEGF-A signals through BMX to induce VCAM-1 expression in endothelial cells, and that VCAM-1 expression is sensitive to ibrutinib in vitro and in atherosclerosis-prone carotid arteries in vivo. These findings suggest that TFKs may contribute to the pathogenesis of atherosclerosis and could represent a novel therapeutic target.