U937 Cells Research Articles

Radiosensitizing Capacity of Fenofibrate in Glioblastoma Cells Depends on Lipid Metabolism

Despite advances in multimodal therapy approaches such as resection, chemotherapy and radiotherapy, the overall survival of patients with grade 4 glioblastoma (GBM) remains extremely poor (average survival time <2 years). Altered lipid metabolism, which increases fatty acid synthesis and thereby contributes to radioresistance in GBM, is a hallmark of cancer. Therefore, we explored the radiosensitizing effect of the clinically approved, lipid-lowering drug fenofibrate (FF) in different GBM cell lines (U87, LN18). Interestingly, FF (50 μM) significantly radiosensitizes U87 cells by inducing DNA double-strand breaks through oxidative stress and impairing mitochondrial membrane integrity, but radioprotects LN18 cells by reducing the production of reactive oxygen species (ROS) and stabilizing the mitochondrial membrane potential. A comparative protein and lipid analysis revealed striking differences in the two GBM cell lines: LN18 cells exhibited a significantly higher membrane expression density of the fatty acid (FA) cluster protein transporter CD36 than U87 cells, a higher expression of glycerol-3-phosphate acyltransferase 4 (GPAT4) which supports the production of large lipid droplets (LDs), and a lower expression of diacylglycerol O-acyltransferase 1 (DGAT1) which regulates the formation of small LDs. Consequently, large LDs are predominantly found in LN18 cells, whereas small LDs are found in U87 cells. After a combined treatment of FF and irradiation, the number of large LDs significantly increased in radioresistant LN18 cells, whereas the number of small LDs decreased in radiosensitive U87 cells. The radioprotective effect of FF in LN18 cells could be associated with the presence of large LDs, which act as a sink for the lipophilic drug FF. To prevent uptake of FF by large LDs and to ameliorate its function as a radiosensitizer, FF was encapsulated in biomimetic cell membrane extracellular lipid vesicles (CmEVs) which alter the intracellular trafficking of the drug. In contrast to the free drug, CmEV-encapsulated FF was predominantly enriched in the lysosomal compartment, causing necrosis by impairing lysosomal membrane integrity. Since the stability of plasma and lysosomal membranes is maintained by the presence of the stress-inducible heat shock protein 70 (Hsp70) which has a strong affinity to tumor-specific glycosphingolipids, necrosis occurs predominantly in LN18 cells having a lower membrane Hsp70 expression density than U87 cells.In summary, our findings indicate that the lipid metabolism of tumor cells can affect the radiosensitizing capacity of FF when encountered either as a free drug or as a drug loaded in biomimetic lipid vesicles.

Cepharanthine inhibits the proliferation of glioblastoma cells by blocking the autophagy–lysosomal pathway

Cepharanthine (CEP) is a Stephania cepharantha-derived bioactive alkaloid that can inhibit the progression of numerous tumors. However, the effects and specific mechanisms of CEP performance in glioblastoma (GBM) remain unclear. Thus, this study focused on exploring the effects of CEP on GBM and clarifying the underlying mechanisms. U251 and U87 cells were selected to estimate the anti-GBM effects of CEP, and the possible targets of CEP were analyzed using RNA sequencing (RNA-seq). Validation experiments based on RNA-seq data were performed to clarify the key pathway by which CEP mediates GBM cells response. Results showed that CEP administration successfully inhibited the proliferation and induced the cell cycle arrest and apoptosis of the GBM cells. RNA-seq analysis after CEP administration identified 386 differentially expressed genes, which were highly enriched in the autophagy–lysosomal pathway. Subsequent findings demonstrated that CEP exhibited the potential to curb GBM progression by causing lysosomal and autophagic dysfunction. Taken together, our results indicate that CEP is a potential drug candidate for GBM intervention.

Peimine induces apoptosis of glioblastoma cells through regulation of the PI3K/AKT signaling pathway.

Glioblastoma (GBM) is one of the most malignant forms of intracranial tumors, with high mortality rates and invariably poor prognosis, due to the limited clinical treatment strategies available. As a natural compound, peimine's favorable pharmacological activities have been widely revealed. However, potential inhibitory effects of peimine on GBM have not been explored. In the present study, both in vitro and in vivo experiments were performed to elucidate the effects of peimine on GBM and to further delineate the underlying molecular mechanism of action. Different doses (0, 25 and 50 µM) of peimine were added to U87 cells, before MTT, colony formation, wound healing, Transwell migration and invasion, reactive oxygen species and mitochondrial transmembrane potential assays were used to measure proliferation, migration, invasion and apoptosis. Furthermore, western blotting was used to examine the possible effects of peimine on the expression of proteins associated with apoptosis and the PI3K/AKT signaling pathway. Subsequently, a GBM mouse xenograft model was used to assess the effects of peimine in vivo. The findings showed that peimine inhibited GBM proliferation, migration and invasion in a dose-dependent manner, whilst also inducing apoptosis. Peimine also reduced tumor growth in vivo. Mechanistically, peimine downregulated the expression of Bcl-2 and Caspase 3, whilst upregulating the protein expression levels of p53, Bax and Cleaved-Caspase 3 in a dose-dependent manner. In addition, PI3K and AKT phosphorylation levels were found to be decreased by peimine in a dose-dependent manner. In conclusion, these findings suggest that peimine may limit GBM growth by regulating the PI3K/AKT signaling pathway both in vitro and in vivo. These findings may have promising clinical implications.

Novel Natural Inhibitors for Glioblastoma by Targeting Epidermal Growth Factor Receptor and Phosphoinositide 3-kinase.

Glioblastoma is an extensively malignant neoplasm of the brain that predominantly impacts the human population. To address the challenge of glioblastoma, herein, we have searched for new drug-like candidates by extensive computational and biochemical investigations. Approximately 950 compounds were virtually screened against the two most promising targets of glioblastoma, i.e., epidermal growth factor receptor (EGFR) and phosphoinositide 3-kinase (PI3K). Based on highly negative docking scores, excellent binding capabilities and good pharmacokinetic properties, eight and seven compounds were selected for EGFR and PI3K, respectively. Among those hits, four natural products (SBEH-40, QUER, QTME-12, and HCFR) exerted dual inhibitory effects on EGFR and PI3K in our in-silico analysis; therefore, their capacity to suppress the cell proliferation was assessed in U87 cell line (type of glioma cell line). The compounds SBEH-40, QUER, and QTME-12 exhibited significant anti-proliferative capability with IC50 values of 11.97 ± 0.73 μM, 28.27 ± 1.52 μM, and 22.93 ± 1.63 μM respectively, while HCFR displayed weak inhibitory potency (IC50 = 74.97 ± 2.30 μM). This study has identified novel natural products that inhibit the progression of glioblastoma; however, further examinations of these molecules are required in animal and tissue models to better understand their downstream targeting mechanisms.

Induction of neuronal differentiation in glioma cells by histone deacetylase inhibitors based on Connectivity Map discovery.

Neuron conversion leads to proliferation inhibition of glioma cells and may be an effective strategy to combat glioma and prevent recurrence. In this study, drug repositioning based on Connectivity Map (CMap) was conducted to discover drugs that could induce the differentiation of glioma cells into neuron-like cells, complemented by in vitro experimental validation. Downregulated neuronal genes in glioma were identified by the Human Protein Atlas database and the GeneCards database, and enrichment analysis and Gene Expression Profiling Interactive Analysis (GEPIA) were performed to ensure their reliability before they were uploaded to CMap for drug screening. The potential drug targets were screened through GEPIA and validated by the Chinese Glioma Genome Atlas database. Cell morphology, proliferation, and neuronal marker expression were detected to evaluate the differentiation-inducing effect of the selected drugs. The bioinformatics analysis identified histone deacetylase (HDAC) inhibitors as potential drugs. HDAC1/3/7 showed the relationship with neuronal genes, and HDAC1 showed the highest level of inverse correlation with neuronal gene expression and had the highest hazard ratio. In vitro study showed that both the pan-HDAC inhibitor belinostat, class I and class IIa HDAC inhibitor valproic acid, and selective HDAC1 inhibitor parthenolide induce morphology alteration, proliferation inhibition, expression of neuronal markers including microtubule-associated protein 2, neuronal nuclei antigen, and synaptophysin in U87 cells. This study suggests that the HDAC inhibitors belinostat, valproic acid, and parthenolide can induce glioma cells to differentiate into neuron-like cells, with HDAC1/3/7 being the likely drug targets and HDAC1 potentially playing an important role in this.

Development of a tumor organoid culture system with peptide-based hydrogels

Peptide-based hydrogel, the polymer materials with a special network structure, are widely used in various fields of biomedicine due to their stable properties and biocompatibility. Environment-responsive self-assembled peptide aqueous solutions can respond to environment changes by the self-assembly of peptides into nanofiber networks. Peptide-based hydrogels well simulate the extracellular matrix and cell growth microenvironment, being suitable for 3D cell culture and organoid culture. To establish a tumor organoid culture system with peptide-based hydrogels, we cultured Panc-1, U87, and H358 cells in a 3D spherical manner using CulX Ⅱ peptide-based hydrogels in 24-well plates for 15 days. The organoids showed a 3D spherical shape, and their sizes increased with the extension of the culture time, with a final diameter ranging from 150 to 300 μm. The organoids had a large number, varying sizes, good cell viability, clear edges, and a good shape, which indicated successful organoid construction. The tumor organoid culture system established in this study with CulX Ⅱ peptide-based hydrogels provides a model for studying tumor pathogenesis, drug development, and tumor suppression.

Preclinical Photodynamic Therapy Targeting Blood Vessels with AGuIX® Theranostic Nanoparticles

Background: Glioblastoma multiforme (GBM) is the most common highly aggressive, primary malignant brain tumor in adults. Current experimental strategies include photodynamic therapy (PDT) and new drug delivery technologies such as nanoparticles, which could play a key role in the treatment, diagnosis, and imaging of brain tumors. Objectives: The purpose of this study was to test the efficacy of PDT using AGuIX-TPP, a polysiloxane-based nanoparticle (AGuIX) that contains TPP (5,10,15,20-tetraphenyl-21H,23H-porphine), in biological models of glioblastoma multiforme and to investigate the vascular mechanisms of action at multiple complexity levels. Methods: PDT effects were studied in monolayer and spheroid cell culture, as well as tumors in chicken chorioallantoic membranes (CAMs) and in mice were studied. Results: Treatment was effective in both endothelial ECRF and glioma U87 cells, as well as in the inhibition of growth of the glioma spheroids. PDT using AGuIX-TPP inhibited U87 tumors growing in CAM and destroyed their vascularization. The U87 tumors were also grown in nude mice. Their vascular network, as well as oxygen partial pressure, were assessed using ultrasound and EPR oximetry. The treatment damaged tumor vessels and slightly decreased oxygen levels. Conclusions: PDT with AGuIX-TPP was effective against glioma cells, spheroids, and tumors; however, in mice, its efficacy appeared to be strongly related to the presence of blood vessels in the tumor before the treatment.

Antitubercular Activity of 7-Methyljuglone-Loaded Poly-(Lactide Co-Glycolide) Nanoparticles.

Loading of natural products into poly-(lactide-co-glycolic) acid (PLGA) nanoparticles as drug delivery systems for the treatment of diseases, such as tuberculosis (TB), has been widely explored. The current study investigated the use of PLGA nanoparticles with 7-methyljuglone (7-MJ), an active pure compound, isolated from the roots of Euclea natalensis A. DC. 7-MJ as well as its respective PLGA nanoparticles were tested for their antimycobacterial activity against Mycobacterium smegmatis (M. smegmatis), drug-susceptible Mycobacterium tuberculosis (M. tuberculosis) (H37Rv), and multi-drug-resistant M. tuberculosis (MDR11). The cytotoxicity of 7-MJ as well as its respective PLGA nanoparticles were tested for their cytotoxic effect against differentiated human histiocytic lymphoma (U937) cells. Engulfment studies were also conducted to determine whether the PLGA nanoparticles are taken up by differentiated U937 cells. 7-MJ has been shown to have a minimum inhibitory concentration (MIC) value of 1.6 µg/mL against M. smegmatis and multi-drug-resistant M. tuberculosis and 0.4 µg/mL against drug-susceptible M. tuberculosis. Whilst promising, 7-MJ was associated with cytotoxicity, with a fifty percent inhibition concentration (IC50) of 3.25 µg/mL on differentiated U937 cells. In order to lower the cytotoxic potential, 7-MJ was loaded into PLGA nanoparticles. The 7-MJ PLGA nanoparticles showed an 80-fold decrease in cytotoxic activity compared to free 7-MJ, and the loaded nanoparticles were successfully taken up by differentiated macrophage-like U937 cells. The results of this study suggested the possibility of improved delivery during TB therapy via the use of PLGA nanoparticles.

Ribosomal protein S3A (RPS3A), as a transcription regulator of colony-stimulating factor 1 (CSF1), promotes glioma progression through regulating the recruitment and autophagy-mediated M2 polarization of tumor-associated macrophages.

Dysregulated expression of ribosomal protein S3A (RPS3A) is associated with the tissue infiltration of immune-related cells in a variety of cancers. However, the role of RPS3A in immune cell infiltration in glioma remains unclear. This study aimed to explore the role of RPS3A in the glioma immune microenvironment.RPS3A expression was detected in tumor tissues from patients with glioma. U251 cells were transfected with RPS3A shRNA (sh-RPS3A) and overexpression vector (pcDNA-RPS3A) and then co-cultured with PMA-induced THP-1 cells. Cell viability, invasion, and apoptosis were detected by Edu staining, Transwell, and flow cytometry, respectively. The expression of tumor-associated macrophage (TAM) M1 and M2 markers was detected with RT-qPCR. Next, the interaction between RPS3A and E4 transcription factor 1 (E4F1) was verified by Co-IP analysis, and the binding of E4F1 to colony-stimulating factor 1 (CSF1) promoter was verified by ChIP analysis. Overexpression vectors of CSF1 and E4F1 were used to treat sh-RPS3A-transfected U251 cells for reversal experiments. Finally, U251 cells transfected with sh-RPS3A adenovirus vectors were subcutaneously injected into nude mice to construct a xenograft tumor model, and the growth and metastasis of glioma in vivo were monitored.RPS3A was significantly upregulated in glioma tissues. Overexpression of RPS3A promoted glioma cell proliferation and invasion and inhibited apoptosis. Moreover, overexpression of RPS3A promoted TAM proliferation, invasion, and M2 polarization. Silencing RPS3A had the opposite effect. Silencing RPS3A inhibited autophagy in U251 cells, whereas rapamycin, an activator of autophagy, reversed the inhibitory effect of RPS3A silencing on TAM M2 polarization. Meanwhile, RPS3A promoted its expression by interacting with E4F1, and E4F1 promoted CSF1 transcriptional activation. Overexpression of CSF1 promoted the proliferation and invasion of U251 cells and reversed the inhibitory effect of RPS3A silencing on TAM proliferation and invasion, but had no effect on TAM M2 polarization. The results of in vivo experiments showed that knockdown of RPS3A significantly inhibited glioma tumor growth and metastasis in vivo.This study revealed that RPS3A recruited TAMs by upregulating E4F1-mediated transcription activation of CSF1, and promoted the M2 polarization of TAMs through autophagy, promoting glioma cell malignant growth and tumor progression.

The calcium‐sensing receptor alleviates endothelial inflammation in atherosclerosis through regulation of integrin β1‐NLRP3 inflammasome

Atherosclerosis (AS) is a chronic inflammatory disease of arteries. Endothelial inflammation is key to the initiation and development of AS. The calcium‐sensing receptor (CaSR) is expressed in endothelial cells (ECs) but its role in endothelial inflammation during AS remains unclear. This study focused on the involvement of CaSR in regulating endothelial inflammation and its underlying mechanisms, providing novel insights for AS therapy. Here, we observed that CaSR agonist NPS‐R568 significantly reduced atherosclerotic lesions and aortic inflammation in high‐fat diet (HFD)‐fed ApoE−/− mice, while enhancing the expression of CaSR in aortic tissues. In vitro, human umbilical vein endothelial cells (HUVECs) exposed to oxidized low‐density lipoprotein (oxLDL) at 20 μg·mL−1 triggered inflammation, as indicated by the upregulation of vascular cell adhesion molecule‐1 (VCAM‐1), interleukin (IL)‐6, and IL‐1β expression, along with increased adherence of THP‐1 or U937 cells to the HUVECs. Additionally, treatment with 20 μg·mL−1 oxLDL led to downregulation of CaSR expression in HUVECs. The administration of CaSR agonist NPS‐R568 or overexpression of CaSR in HUVECs resulted in a significant reversal of inflammation induced by oxLDL. Mechanistically, CaSR was found to mitigate NLRP3 inflammasome activation by downregulating the protein level of integrin β1. In conclusion, our study elucidates the beneficial role of CaSR in reducing endothelial inflammation in AS through the regulation of integrin β1 and the subsequent NLRP3 inflammasome. CaSR emerges as a promising target for potential therapeutic interventions in AS.

4-Furanylvinylquinoline derivative as a new scaffold for the design of oxidative stress initiator and glucose transporter inhibitor drugs

In the present study, a detailed analysis of the effect of a substitution at the C4 position of the quinoline ring by styryl or furanylvinyl substituents on the structure-antitumour activity relationship was conducted. After analysing a library of derivatives from the styrylquinoline and furanylvinylquinoline groups, we selected the most active (IC50 below 100 nM) derivative 13, which contained the strongly electron-withdrawing nitro group in the furan substituent. The mechanism of action of this compound was studied on cell lines that differed in their p53 protein status. For this derivative, both cell cycle arrest (in G2/M phase in both HCT 116 cell lines and S phase for U-251 cell line) and the induction of apoptosis (up to 66% for U-251 cell line) were revealed. These studies were then confirmed by other methods at the gene and protein levels. Interestingly, we observed differences in the mechanism of action depending on the presence and mutation of the p53 protein, thus confirming its key role in cellular processes. Incubation with derivative 13 resulted in the induction of oxidative stress and triggered a cascade of cellular defence proteins that failed in the face of such an active compound. In addition, the results showed an inhibition of the GLUT-1 glucose transporter, which is extremely important in the context of anti-cancer activity.

Exploring the Effect of Resveratrol, Tyrosol, and Their Derivatives on Platelet-Activating Factor Biosynthesis in U937 Cells.

Platelet-activating factor (PAF) is a potent lipid mediator, involved in thrombosis, inflammation, and atherosclerosis. The protective effect of wine and olive oil against atherosclerotic diseases is largely attributed to their phenolic compounds and mostly to resveratrol and tyrosol. Both compounds have been reported to inhibit PAF biosynthesis in interleukin-1β (IL-1β)-stimulated monocytes and also to attenuate PAF biosynthesis in cell lysates. The aim of this study was to investigate the effects of resveratrol, tyrosol, and their derivatives on unstimulated U937 cells and to explore the intracellular messaging pathways that participate in the activation of PAF biosynthesis in the same cell line. Tyrosol and its derivatives did not exert any substantial effect on PAF biosynthesis. Resveratrol (50 and 100 μM), as well as its methoxy derivative (5-20 μM), caused a reduction in the PAF biosynthetic enzymes' activity by 20-43% after 24 h of incubation. On the other hand, lower resveratrol concentration (10 μM) and higher concentration of the methoxy derivative (50 μM) increased the Ca2+-dependent lyso-PAF acetyltransferase (LysoPAF-ATC) activity by 28-45% after half-hour incubation via p38 mitogen-activated protein kinase (p38-MAPK) action. IL-1β activated PAF biosynthetic pathways via different signaling pathways, with phospholipase C-β (PLC-β) being a key enzyme.

Abstract A021: HRI inhibition by hemin as a novel targeted therapy for glioblastoma via the integrated stress response

Abstract The treatment of glioblastoma (GBM), a highly malignant brain tumor, is critically hindered by the ineffectiveness of current modalities such as surgery, radiation, and chemotherapy. These traditional methods fail to completely remove the tumor mass and lack the ability to discriminate between cancerous and normal brain cells, often resulting in damage to healthy tissue and recurrence of the disease. This underscores an urgent necessity to develop novel therapeutic strategies that can target tumor cells with precision, offering hope for improved survival rates and quality of life for GBM patients. This study investigates targeted therapy, focusing on the Integrated Stress Response (ISR) that cancer cells harness to survive hypoxic stress. Specifically, it demonstrates that EIF2AK1, which encodes Heme-regulated eIF2α kinase (HRI), is activated under hypoxia and co-expressed with the glioma stem cell marker SOX2, which specifically happens in glioma cells, increasing the targeted accuracy of the repurposing drug. This correlation, indicating hypoxia-driven stemness, is confirmed at both the genetic level and through Gene Set Enrichment Analysis (GSEA). Furthermore, GSEA in Spatial Transcriptomics shows hypoxia-induced glycolysis, disrupting the tumor microenvironment and causing necrotic cell death. Stemness phenotype is induced in the peripheral cells due to the unfavorable hypoxic environment. Hemin, an HRI inhibitor, has been repurposed to inhibit ISR and mitigate hypoxia. Treatment with Hemin on the U87 cell line resulted in IC50 values of 23.50 µM and 52.46 µM at 24 and 48 hours, respectively, surpassing Temozolomide's efficacy. A decrease in HRI expression after the Hemin treatment suggests the and ISR activity and, potentially, hypoxia. This would reverse the unfavorable microenvironment so that the stemness phenotype doesn’t spread. Potentially, invasiveness and recurrences of GBM in clinic situation would decrease, thus potentially improving patient prognosis. The therapeutic potential of Hemin is enhanced by its ability to kill glioma cells directly and accurately in the glioma cell in original TME when cells are proliferating with adequate oxygen. Therefore, this study demonstrates the therapeutic potential of repurposing Hemin, an HRI inhibitor, to precisely target hypoxia-induced glioma stem cells in glioblastomas, disrupting the aggressive tumor microenvironment to potentially improve patient prognosis. Citation Format: Xingchuan Ma. HRI inhibition by hemin as a novel targeted therapy for glioblastoma via the integrated stress response [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A021.

Anticancer evaluation of Co(III) complex derived from 1-isonicotinoyl-4-(4-nitrophenyl)-3-thiosemicarbazide: Structural characterization, photophysical, and Hirshfeld studies

A new cationic complex, [Co((intph)(en)2]Cl, derived from the 1-isonicotinoyl-4-(4-nitrophenyl)-3-thiosemicarbazide (H2intph), is reported. The synthesized ligand and its corresponding Co(III) complex were successfully characterized by applying FT-IR and UV–visible spectroscopic techniques and single crystal ray diffraction data. Molecular geometries of the ligand and its Co(III) complex were accurately determined from their respective X-ray crystallographic analysis. The ligand and [Co((intph)(en)2]Cl crystallize in Triclinic and monoclinic systems with space groups P-1 and P 21/n, respectively. The crystal structures of H2intph and [Co((intph)(en)2]Cl are stabilized by weak C-H⋯O, N-H⋯O, and C-H⋯Cl hydrogen bonding interactions. Hirshfeld surface analysis was accomplished to investigate intermolecular hydrogen bonding interactions found in ligand H2intph and [Co((intph)(en)2]Cl. The cytotoxicity of the ligand and the complex [Co((intph)(en)2]Cl was assessed for their anticancer potential against human glioblastoma (U87) and Dalton lymphoma (DL) cell lines. The complex exhibited IC50 values of 100 μg/mL for U87 cells and 120 μg/mL for DL cells, indicating the concentration at which 50 % of cell viability was inhibited. In comparison, the ligand was less effective in the MTT assay against both U87 and DL cells. These results suggest that the complex [Co((intph)(en)2]Cl significantly reduces glioblastoma cell viability. Treatment with the complex induced cell death through both apoptotic and necrotic pathways, as evidenced by Hoechst/PI double staining. Additionally, there was an increase in intracellular reactive oxygen species (ROS), highlighting the role of oxidative stress in the anticancer activity of the [Co((intph)(en)2]Cl complex. Furthermore, fluorescence studies were carried out which revealed the order of fluorescence behaviors between the ligand and the Co(III) complex to be Co(III) complex > H2intph.

Discovery and structure-activity relationship study of nicotinamide derivatives as DNA demethylase ALKBH2 inhibitors

AlkB homolog 2 (ALKBH2) is a Fe (II) and 2-oxoglutarate (2OG)-dependent DNA demethylase. It has been reported to be highly expressed in many cancers including glioblastoma (GBM) and affected disease progression by regulating gene expression. Small molecule inhibitors of ALKBH2 might be used as disease intervention reagents or chemical tools for bio-functional studies of ALKBH2, but currently no potent and selective ALKBH2 inhibitors are reported. We herein disclose a new potent and selective ALKBH2 inhibitor (AH2-15c), which showed an IC50 value of 0.031 ± 0.001 μM in a fluorescence polarization (FP) assay and exhibited more than 200-fold selectivity towards ALKBH2 versus other AlkB subfamily members. Since AH2-15c showed very low cellular activity due to its poor cell membrane permeability originating from the carboxyl group, we investigated the un-hydrolyzed counterpart AH2-14c. AH2-14c could directly bind to ALKBH2 and increase the abundance of DNA N3-methylcytosine (3meC) modifications in GBM U87 cells, with a superior effect to AH2-15c. In addition, AH2-14c exhibited much better activities of anti-viability, anti-proliferation and anti-migration against U87 cells. Collectively, we discovered the first potent and selective ALKBH2 inhibitor, which could be taken as a foundation for future drug development and mechanism of action studies.

Non-Immune-Mediated, p27-Associated, Growth Inhibition of Glioblastoma by Class-II-Transactivator (CIITA).

Previous works have shown that the expression of Class-II-Transactivator (CIITA) in tumor cells reduces the growth of glioblastoma (GB) in animal models, but immune effects cannot solely explain this. Here, we searched for immune-independent effects of CIITA on the proliferation of GB. Murine GL261 and human U87, GM2 and GM3 malignant glioma cells were transfected with CIITA. NSG (immunodeficient) and nude (athymic) mice were injected in the striatum with GL261-wildtype (-WT) and -CIITA, and tumor growth was assessed by immunohistology and luminescence reporter genes. Clonogenic, sphere-formation, and 3D Matrigel-based in vitro growth assays were performed to compare the growth of WT versus CIITA-expressing murine and human cells. Bulk RNA sequencing and RT2 qRT-PCR profiler arrays were performed on these four cell lines to assess RNA expression changes following CIITA transfection. Western blot analysis on several proliferation-associated proteins was performed. The intracerebral growth of murine GL261-CIITA cells was drastically reduced both in immunodeficient and athymic mice. Tumor growth was reduced in vitro in three of the four cell types. RNA sequencing and RT2 profiler array experiments revealed a modulation of gene expression in the PI3-Akt, MAPK- and cell-cycle regulation pathways following CIITA overexpression. Western blot analysis showed an upregulation of p27 in the growth-inhibited cells following this treatment. PDGFR-beta was downregulated in all cells. We did not find consistent regulation of other proteins involved in GB proliferation. Proliferation is drastically reduced by CIITA in GB, both in vivo and in vitro, notably in association with p27-mediated inhibition of cell-cycle pathways.

Glioblastoma cells alter brain endothelial cell homeostasis and tight junction protein expression in vitro.

Glioblastoma (GBM) is an aggressive therapy-resistant brain tumour that may impacts the integrity of the blood-brain barrier (BBB). The BBB is a protective barrier of the central nervous system formed mainly by endothelial cells. This study aimed to investigate the in vitro effect of GBM cells on the BBB. Brain endothelial (bEnd.3) cells were used as a model of the BBB. Glioblastoma-conditioned media (CM) was extracted at the 48-h (h) time-point from the U87 GBM cells and diluted to 40% with fresh media. The effect of the U87-CM collected at 48h on bEnd.3 cell growth was evaluated following 48 and 72h of treatment using the xCELLigence system. Additionally, bEnd.3 cell growth was also investigated in a U87 and bEnd.3 co-culture model continuously for 48h using the xCELLigence system. The migration of bEnd.3 cells was assessed following 48 and 72h using the migration scratch assay. The barrier integrity was evaluated continuously for 1h using the transwell permeability, and the tight junction (TJ) protein expression was evaluated using Western blot assay following 48 and 72h. There was a significant decrease in bEnd.3 cell growth following 32h (p < 0.05), 40h (p < 0.01), and 48h (p < 0.001) of treatment with U87-CM, while co-culturing of bEnd.3 and U87 cells increased cell growth following 16h (p < 0.05), 24h (p < 0.001), 32h (p < 0.01), 40h (p < 0.001), and 48h (p < 0.001). The migration of bEnd.3 cells significantly increased following both 24 (p < 0.05) and 48h (p < 0.01) of treatment with U87-CM. The permeability of bEnd.3 cells co-cultured with U87 for 48h was significantly increased (p < 0.05) at the 15- and 30-min time points. Furthermore, the expression of ZO-1 and occludin was significantly increased (p < 0.05) in both bEnd.3 cells treated with U87-CM as well as bEnd.3 cells co-cultured with U87 cells. The current findings suggest that U87 cells alter the integrity of bEnd.3 cells possibly through the secretomes in the CM and through cell-cell interactions in co-culture models. This may assist in the understanding of the mechanisms by which GBM affects the BBB, which may aid in the management thereof.

Inulae Flos is a potential herbal medicine to treat glioma: a study based on gene expression profile analysis, network pharmacology and molecular docking

Inulae Flos is a promising herbal medicine; however, its underlying mechanism in treating glioma remains unclear. This study aimed to elucidate the potential active ingredients and mechanisms of Inulae Flos in glioma treatment. Differentially expressed genes (DEGs) associated with gliomas were identified by analyzing the GSE186057 dataset. The bioactive components of Inulae Flos were searched in the Traditional Chinese Medicine Systems Pharmacology database, and related targets were obtained from the Swiss Target Prediction database. A protein-protein interaction (PPI) network was constructed using the STRING database. Next, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) of these common targets were analyzed using the DAVID database. Finally, AutoDock Vina was used for molecular docking analysis. The tumor-suppressive properties of the crude extract of Inulae Flos (XFH) and britanin were then evaluated with in vitro and in vivo assays. Nineteen active ingredients were obtained from Inulae Flos, and 20 DEGs were identified as the targets of Inulae Flos in glioma treatment. Britanin, luteolin and 1-O-Acetylbritannilactone were identified as the key ingredients. PIK3R1, CDK2, CCNB1, MAPK1, MAPK8, CCNA2, and AR were considered to be the hub target genes of Inulae Flos in glioma treatment. Good binding affinity was observed between the key components and hub targets. In addition, in vitro studies showed that XFH and britanin, a key component of Inulae Flos, could inhibit the growth, migration and invasion glioma cell lines U87 and U138, and repress the tumorigenesis of U138 cells in nude mice. Inulae Flos is promising for glioma treatment, and it exerts its anti-tumor activities via multiple components, targets and pathways.

CSIG-23. CYTOMEGALOVIRUS-INFECTED HUMAN GLIOBLASTOMA CELL LINES SHOW AN AGGRESSIVE PHENOTYPE ASSOCIATED WITH UPREGULATION OF IL-6/STAT3 AND AKT SIGNALING

Abstract BACKGROUND Cytomegalovirus (CMV) has been implicated in glioblastoma (GBM) pathogenesis by affecting stemness, angiogenesis and immune pathways. Clinical trials targeting CMV in GBM patients have shown some early promise, and CMV seropositivity has been associated with poorer outcomes. However, the underlying mechanisms remain unclear. Here we investigated the effects of CMV infection on critical signaling pathways in GBM (IL6/STAT3, and Akt signaling) based on the hypothesis that CMV may contribute to poorer outcomes in GBM by increasing oncogenic signaling. MATERIALS AND METHODS Human U251 and LN229 GBM cell lines were infected with mCherry expressing human CMV TB40 strain at a multiplicity of infection (MOI) of 0.5. We performed basic phenotypic studies in vitro and investigated the status of IL6/STAT3, and Akt signaling by Western blotting. RESULTS Both LN229 and U251 cell lines were readily infectable by CMV. Infection of U251 cells was over 90% and in LN229 cells was approximately 60%. Interestingly expression of CMV was sustained over many passages in these cell lines. Infection was also verified by the presence of the CMV pp65 protein assessed by Western blotting. Measurement of cell proliferation indicated faster growth after CMV infection. Interrogation of key pro-oncogenic signaling pathways in GBM revealed a robust upregulation of IL6, as well as phospho(Tyr705)-STAT3 and phospho(Thr308)-Akt. This elevation of pro-oncogenic signaling pathways was observed in both cell lines compared with controls. CONCLUSIONS Here we show for the first time that infection of human GBM cell lines with CMV results in a more aggressive phenotype associated with upregulation of IL6/STAT3 signaling as well as a significant increase in phospho-Akt levels. We are currently studying sensitivity to standard therapies and additional molecular changes in these cells. These data support the hypothesis that CMV causes more aggressive disease and that CMV is a relevant therapeutic target in GBM.

DDEL-09. AS1411 APTAMER-CONJUGATED NANOSPHERES FOR TARGETING GLIOBLASTOMA THERAPY

Abstract Postoperative chemotherapy remains essential for treating glioblastoma (GBM), with nanocarrier-based drug delivery emerging as the most efficient method. However, non-specific delivery across the blood-brain barrier (BBB) can limit drug accumulation in tumors and cause damage to nearby tissues. As cancer progresses, angiogenic processes lead to the formation of an irregular blood-tumor barrier (BTB), necessitating nanodrug platforms for precise targeting and efficient drug delivery to cancer cells. In this study, we aimed to demonstrate targeted cancer therapy by selectively identifying tumor cells overexpressing nucleolin (NCL) protein using Dox-loaded AS1411 aptamer-conjugated nanospheres. Drug nanocarriers were synthesized from small molecules with sizes ranging from 100 to 300 nm to facilitate drug delivery. Selective drug delivery and cellular uptake were demonstrated for NCL-positive GBM cells (U87 and U251) compared to NCL-negative normal human astrocyte (NHA) cells. Flow cytometric analysis using FAM dye-labeled AS1411 aptamer-conjugated nanospheres confirmed that drug delivery to GBM U87 and U251 cells was actively targeted by specific AS1411-NCL interactions. Confocal laser scanning microscopy and cytotoxicity analysis confirmed that inoculation of Dox-loaded AS1411 aptamer-conjugated nanospheres induced selective internalization in GBM U87 and U251 cells. Moreover, to evaluate cytotoxicity and anti-tumor effects after treatment with PBS, Apt-Nanospheres, Free Dox, and Dox-Apt-Nanospheres, the results were analyzed through cell counting kit (CCK-8) analysis, evaluation of differences in 3D tumor sphere radii, and an in vivo GBM xenograft tumor model. The AS1411 aptamer-conjugated nanosphere drug delivery system was developed for dual-target treatment of GBM. AS1411-mediated specific recognition and drug accumulation significantly enhanced binding to NCL-positive U87 and U251 cells and improved cytotoxicity efficiency compared to Free Dox. Additionally, this study demonstrated that the active targeting model using aptamer-mediated drug delivery was more effective in improving drug penetration and retention in tumor cells than non-specific enhanced permeability and retention (EPR)-mediated delivery and passive drug delivery.