U87MG Glioma Research Articles

Combination of Caffeic Acid Phenethyl Ester and Crocin Realign Potential Molecular Markers in U87-MG Glioma Cells

Glial tumors are the most common primary malignant central nervous system tumors. They are hard to treat, not only because of the deregulation in multiple pathways but also because they are not contained in a well-defined mass with clear borders. The use of a single therapeutic agent to target gliomas has yielded unsatisfactory results. A combination of molecules targeting multiple pathways may prove to be a better alternative. The effect of caffeic acid phenethyl ester and crocin on the proliferation and death of U87-MG cells over a concentration range was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays. A colony formation assay was used to measure the effect of caffeic acid phenethyl ester and crocin on contact inhibition and anchorage independence ability of U87-MG cells. Furthermore, apoptosis in U87-MG cells was analyzed by propidium iodide assay. Real-time polymerase chain reaction and Western blotting were performed to determine the expression level of p53, epidermal growth factor receptor, and proliferating cell nuclear antigen. Caffeic acid phenethyl ester and crocin when used in combination present an anticancer potential for glioma. These molecules, in combination, inhibit proliferation and induce apoptosis in U87-MG glioma cells. Our results provide evidence that combination treatment realigns the expression paradigm of p53, epidermal growth factor receptor, and proliferating cell nuclear antigen in cotreated U87-MG cells. The combination of caffeic acid phenethyl ester and crocin led to inhibition in glioma cell proliferation and might prove to be an effective adjunct to the therapies in vogue.

Abstract 1234: Untargeted Lipidomics in U87-MG Glioma Cells

Abstract 1234: Untargeted Lipidomics in U87-MG Glioma Cells

Synthesis and anticancer activity evaluation of substituted carbazole bearing thiosemicarbazide derivatives against human glioma U87 MG cell line

Both carbazole and thiosemicarbazide scaffold showed various potential biological activities in medicinal chemistry. In this research work, we synthesized a series of carbazole bearing thiosemicarbazide derivatives (17-28) and evaluated thier in vitro cytotoxicity (IC50) profile on the U87 MG cell line using MTT assay. All target compounds were well characterized by NMR and HRMS mass spectroscopy. In series, six compounds (17, 20, 21, 22, 23, 28) found better in vitro cytotoxicity (IC50) values were 26.50 µM, 34.0 µM, 39 µM, 80 µM, 62 µM, 50 µM respectively compare to standard drug Temozolomide (IC50 = 100 µM). The SAR study of all final compounds (17-28) were also analyzed on the basis of different substituents on 6th position of carbazole scaffold bearing thiosemicarbazide derivatives against U87 MG cell line. All of the above studies showed that carbazole bearing thiosemicarbazide derivatives (17-28) showed anticipated anticancer activity against U87 MG glioma cell line.

Synthesis and anticancer activity evaluation of substituted carbazole bearing thiosemicarbazide derivatives against human glioma U87 MG cell line

Synthesis and anticancer activity evaluation of substituted carbazole bearing thiosemicarbazide derivatives against human glioma U87 MG cell line

Carnitine octanoyltransferase is important for the assimilation of exogenous acetyl-L-carnitine into acetyl-CoA in mammalian cells

In eukaryotes, carnitine is best known for its ability to shuttle esterified fatty acids across mitochondrial membranes for β-oxidation. It also returns to the cytoplasm, in the form of acetyl-L-carnitine (LAC), some of the resulting acetyl groups for posttranslational protein modification and lipid biosynthesis. While dietary LAC supplementation has been clinically investigated, its effects on cellular metabolism are not well understood. To explain how exogenous LAC influences mammalian cell metabolism, we synthesized isotope-labeled forms of LAC and its analogs. In cultures of glucose-limited U87MG glioma cells, exogenous LAC contributed more robustly to intracellular acetyl-CoA pools than did β-hydroxybutyrate, the predominant circulating ketone body in mammals. The fact that most LAC-derived acetyl-CoA is cytosolic is evident from strong labeling of fatty acids in U87MGcells by exogenous 13C2-acetyl-L-carnitine. We found that the addition of d3-acetyl-L-carnitine increases the supply of acetyl-CoA for cytosolic posttranslational modifications due to its strong kinetic isotope effect on acetyl-CoA carboxylase, the first committed step in fatty acid biosynthesis. Surprisingly, whereas cytosolic carnitine acetyltransferase is believed to catalyze acetyl group transfer from LAC to coenzyme A, CRAT-/- U87MGcells were unimpaired in their ability to assimilate exogenous LAC into acetyl-CoA. We identified carnitine octanoyltransferase as the key enzyme in this process, implicating a role for peroxisomes in efficient LAC utilization. Our work has opened the door to further biochemical investigations of a new pathway for supplying acetyl-CoA to certain glucose-starved cells.

Design, synthesis and antitumor activity of novel thiophene- triazine derivatives bearing arylurea unit as potent PI3K/mTOR inhibitorss

In this article, we designed and synthesized a series of novel thiophene-triazine derivatives bearing arylurea unit as potent dual PI3K/mTOR inhibitors. The cytotoxicity of all the target compounds were evaluated against nine cancer cell lines (breast cancer cell line MCF-7, lung cancer cell lines A549, NCI-H460, H2228 and H1975, cervical cancer cell lines Hela and Hela-MDR, ovarian cancer cell lines Ovcar-2 and glioma U87MG) and the kinase inhibitory activity against PI3K/mTOR kinases was also tested. The results demonstrated that most of the target compounds exhibited moderate to excellent activity and high selectivity against one or more cancer cell lines. Among them, seven compounds displayed better activity than lead compound GDC-0941. The inhibitory activity of the most promising compound on nine cancer cell lines was 302.5 times better than that of GDC-0941 with the IC50 values as low as 0.008 ± 0.002 μM, and the inhibitory activity against PI3Kα and mTOR kinase was excellent, with the IC50 values of 177.41 and 12.24 nM, respectively, indicating that it was a potential dual PI3Kα/mTOR inhibitor. The Structure-Activity Relationships (SARs) indicated that the introduction of the arylurea group significantly improved the cellular and kinase activities of the target compounds. Moreover, the results of toxicity and hemolysis experiments demonstrated that the most promising compound had low toxicity and good safety. The results of PCR assay and molecular docking modes showed that it was a potential PI3K/mTOR inhibitor, which was worthy of further study.

Controlling Disassembly of Paramagnetic Prodrug and Photosensitizer Nanoassemblies for On-Demand Orthotopic Glioma Theranostics

Controlling delivery and release of therapeutic agents to accomplish on-demand synergistic therapy of orthotopic gliomas is desired but challenging. Here, we report a glioma targeting and redox activatable theranostic nanoprobe (Co-NP-RGD1/1) for magnetic resonance (MR) and fluorescence (FL) bimodal imaging-guided on-demand synergistic chemotherapy/photodynamic therapy (Chemo-PDT) of orthotopic gliomas. Co-NP-RGD1/1 is formed via molecular coassembly of two paramagnetic and fluorogenic small-molecule probes CPT-RGD and PPa-RGD at an optimized molar ratio of 1/1, which shows a high longitudinal relaxivity (r1 = 17.0 ± 0.6 mM-1 s-1, 0.5 T) but weak FL emissions and low Chemo-PDT activity. Upon reduction by endogenous glutathione (GSH), Co-NP-RGD1/1 disassemble and release small molecules 2-RGD, chemodrug camptothecin (CPT), and near-infrared (NIR) photosensitizer (PS) PPa-SH that further binds to endogenous albumin to form PPa-SH-albumin complex, allowing to turn on FL, chemotherapeutic efficacy, and PDT activity for synergistic Chemo-PDT of orthotopic U87MG or U251 gliomas in living mice. Moreover, Co-NP-RGD1/1 can also allow noninvasive detection and monitoring of orthotopic brain tumor growth via FL and MR imaging. Findings suggest the potential of cascade coassembly and stimuli-controlled intracellular disassembly strategy for constructing targeted and activatable nanoagents for improving combinational cancer theranostics.

COX-2 Acts as a Key Mediator of Trifluoperazine-induced Cell Death in U87MG Glioma Cells

Glioblastoma multiforme (GBM) is one of the most common brain tumors with a poor prognosis. Previously, we reported that trifluoperazine (TFP), a well-known antipsychotic, has anti-glioma activity through the modulation of intracellular calcium levels. The present study aimed to investigate the anti-cancer mechanism of action of TFP on glioma cells. The effect of TFP on U87MG cells was examined using a viability assay, flow cytometry, enzyme-linked immunosorbent assay, quantitative real-time PCR, western blot analysis, colony formation, and immunocytochemistry. TFP treatment decreased cell viability. To test the possible involvement of COX-2 in the anticancer activity of TFP on U87MG cells, a COX-2 inhibitor was applied. COX-2 inhibitor pretreatment restored TFP-induced reduction in viability to the control level. Additionally, TFP-induced changes in the apoptotic cell population, production of prostaglandins (PGE2, PGD2, 15d-PGJ2), and nuclear translocation of peroxisome proliferator-activated receptor γ (PPARγ) were ameliorated by COX-2 inhibitor pretreatment. TFP suppressed the proliferation of U87MG glioma cell in a COX-2/PPARγ-dependent manner.

CSIG-02. FOSL1 PROMOTES GLIOMA STEM CELLS TRAITS THROUGH INTERACTING WITH ITS BINDING PROTEIN PHOSPHORYLATED STAT3

Abstract BACKGROUND Glioma stem cells (GSCs) have key roles in tumorigenesis, progression, and resistance to conventional treatments for glioblastoma. We reported that TRPM7 channels, which fused with C-terminal kinase, endow glioma cells with stem cell-like capacities of self-renewal. Here, we investigated the role of TRPM7 downstream target gene FOSL1’s post transcription in glioma stemness. METHODS 1) The immunohistochemical staining for FOSL1 was performed using the rabbit polyclonal anti-FOSL1 antibody in glioma tissue arrays from 76 Chinese patients and 10 normal individuals. The staining intensity of cells in TMA was evaluated in three different fields (≥100 cells/field). The semi-quantitative HSCORE was calculated for FOSL1. 2) Upon suppression of FOSL1 by siRNA FOSL1, GSC markers, CD133 expression was evaluated by flow cytometry using PE anti-human CD133 antibody, while ALDH1 enzymatic activity was assessed using an Aldefluor kit, in A172 and U87MG glioma cell lines and patient-derived xenoline PDX-L14 of proneural subtype. 3) To assay FOSL1 gene promoter activity, the 5’-flanking region of the human FOSL1 gene (1201bp) was inserted into the firefly luciferase reporter vector pGL3-Basic between MluI and BglII sites. For mutant construct, STAT3 binding sites were mutated using Q5 site-directed mutagenesis kit. RESULTS 1) Quantification of the IHC results showed that FOSL1’s positive nuclear staining was significantly higher in GBM (n=13, p=0.0005), grade III (n=12, p=0.0116), and grade II astrocytoma (n=51, p=0.0485) compared to that of normal brain tissue (n=10). 2) GSC markers CD133 and ALDH1 were positively associated with FOSL1 in glioma. 3) Phosphorylated STAT3 directly binds to the FOSL1 promoter and the activation levels of STAT3 have a positive effect on the transcriptional activity of FOSL1. CONCLUSION Our results demonstrated the role of TRPM7-regulated STAT3 activation directly regulated FOSL1 gene transcription, which shed new light on TRPM7/FOSL1-directed therapeutics in glioma. (This study was supported by NIH NIGMS GM121230)

A feasible strategy of fabricating camptothecin (SN38)-loaded holmium ferrite nanocarrier delivery for glioma treatment

Malignant gliomas are the most prevalent and deadly primary brain tumors. The life expectancy of people with gliomas only slightly increases through surgical procedures, radiation, and chemotherapy. Magnetic nanocarriers must be developed to enable drug delivery using a magnetic field. A utilized to fabricate holmium ferrite nanoparticles is described herein. β-Cyclodextrin-polyethylene glycol (PEG) conjugate is used as a coat for the holmium ferrite nanoparticles. X-ray diffraction, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy are all used to study the nanoparticles. This size range of nanoparticles is optimal for efficient drug delivery. The in vitro cytotoxicity of the fabricated nanoparticles was examined using U87MG and LN229 glioma cancer cells. The acridine orange/ethidium bromide and nuclear staining methods examined the morphological changes in the U87MG and LN229 glioma cells. The mode of cell death mechanism was investigated by Annexin V-FITC/PI flow cytometry methods. The possibility for successful SN38 delivery for the treatment of glioma cancer exists with the SN38@HF-β-CD-PEG.

New Hygrocins K-U and Streptophenylpropanamide A and Bioactive Compounds from the Marine-Associated Streptomyces sp. ZZ1956.

Marine-derived Streptomyces actinomycetes are one of the most important sources for the discovery of novel bioactive natural products. This study characterized the isolation, structural elucidation and biological activity evaluation of thirty compounds, including twelve previously undescribed compounds, namely hygrocins K-U (5-13, 17 and 18) and streptophenylpropanamide A (23), from the marine-associated actinomycete Streptomyces sp. ZZ1956. Structures of the isolated compounds were determined by a combination of extensive NMR spectroscopic analyses, HRESIMS data, the Mosher's method, ECD calculations, single crystal X-ray diffraction and comparison with reported data. Hygrocins C (1), D (2), F (4), N (8), Q (11) and R (12), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), echoside C (27), echoside A (28) and 11,11'-O-dimethylelaiophylin (30) had antiproliferative activity (IC50: 0.16-19.39 μM) against both human glioma U87MG and U251 cells with hygrocin C as the strongest active compound (IC50: 0.16 and 0.35 μM, respectively). The analysis of the structure-activity relationship indicated that a small change in the structures of the naphthalenic ansamycins had significant influence on their antiglioma activities. Hygrocins N (8), O (9), R (12), T (17) and U (18), 2-amino-6-hydroxy-7-methyl-1,4-naphthoquinone (21), 2-acetamide-6-hydroxy-7-methyl-1,4-naphthoquinone (22), 3'-methoxy(1,1',4',1″-terphenyl)-2',6'-diol (26), echoside C (27) and echoside A (28) showed antibacterial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli with MIC values of 3-48 μg/mL.

Three new compounds with their anti-glioma effects from the roots of Arnebia guttata Bunge

Three new compounds, arneatas A-C (1–3), together with three known compounds (4–6) were isolated from the roots of Arnebia guttata Bunge. The structures were established on the basis of extensive spectroscopic data including NMR and HRESIMS. All the new compounds (1–3) were tested for their cytotoxic activity against two glioma cell lines (U118-MG and U373-MG) in vitro after treatment for 48 h. Compound 1 exhibited moderate cytotoxic activity against U118-MG and U373-MG glioma cell lines, with IC50 values of 10.4 and 17.5 µM, respectively.

Hypericin, a potential new BH3 mimetic.

Many types of cancer such as prostate cancer, myeloid leukemia, breast cancer, glioblastoma display strong chemo resistance, which is supported by enhanced expression of multiple anti-apoptotic Bcl-2, Bcl-XL and Mcl-1 proteins. The viable anti-cancer strategies are based on developing anti-apoptotic Bcl-2 proteins inhibitors, BH3 mimetics. Our focus in past years has been on the investigating a new potential BH3 mimetic, Hypericin (Hyp). Hyp is a naturally occurring photosensitive compound used in photodynamic therapy and diagnosis. We have demonstrated that Hyp can cause substantial effects in cellular ultrastructure, mitochondria function and metabolism, and distribution of Bcl2 proteins in malignant and non-malignant cells. One of the possible mechanisms of Hyp action could be the direct interactions between Bcl-2 proteins and Hyp. We investigated this assumption by in silico computer modelling and in vitro fluorescent spectroscopy experiments with the small Bcl2 peptide segments designed to correspond to Bcl2 BH3 and BH1 domains. We show here that Hyp interacts with BH3 and BH1 peptides in concentration dependent manner, and shows the stronger interactions than known BH3 mimetics, Gossypol (Goss) and ABT-263. In addition, interactions of Hyp, Goss and ABT263, with whole purified proteins Bcl-2 and Mcl-1 by fluorescence spectroscopy show that Hyp interacts stronger with the Bcl-2 and less with Mcl-1 protein than Goss or ABT-263. This suggest that Hyp is comparable to other BH3 mimetics and could be explore as such. Hyp cytotoxicity was low in human U87 MG glioma, similar to that of ABT263, where Goss exerted sufficient cytotoxicity, suggesting that Hyp acts primarily on Bcl-2, but not on Mcl-1 protein. In combination therapy, low doses of Hyp with Goss effectively decreased U87 MG viability, suggesting a possible synergy effect. Overall, we can conclude that Hyp as BH3 mimetic acts primarily on Bcl-2 protein and can be explored to target cells with Bcl-2 over-expression, or in combination with other BH3 mimetics, that target Mcl-1 or Bcl-XL proteins, in dual therapy.

Elevated expression of cholesterol transporter LRP-1 is crucially implicated in the pathobiology of glioblastoma.

Glioblastoma (GBM) is the most common primary malignant brain tumor with a grave prognosis. The present study evaluated the expression of Cholesterol transporter [importer -Lipoprotein Receptor-related Protein-1 (LRP-1) and exporter -ATP-binding cassette transporters-1 (ABCA-1)] in GBM and their implications in tumor-biology, clinical outcome and therapeutic potentials. The mRNA and protein expression was assessed by qRT-PCR and immunohistochemistry, respectively, in 85 GBMs. For comparison, 25 lower-grade astrocytomas (IDH-mutant, grade-2/3) [LGA] 16 cases of high-grade astrocytomas (IDH-mutant, grade-4) [HGA] were also evaluated. In-vitro analysis was performed on U87MG and LN229 glioma cell line. The expression of LRP-1 (mRNA and protein) was significantly higher in GBM than LGA, HGA and normal brain (NB) [p-values 0.007, 0.003 and <0.001 for mRNA; 0.024, <0.001 and <0.001 for immunohistochemistry]. Majority of the GBMs (82.4%) showed strong immunoreactivity for LRP-1, and all tumor cases were positive while the normal brain was negative. LRP-1 immunoreactivity positively correlated with the MIB-1 labeling index (p-value-0.013). LRP-1 knockdown in-vitro was associated with decreased cell survival, proliferation, migration, invasion, and increased apoptosis. Similar effect was also demonstrated by Receptor Associated Protein (RAP), a LRP-1 inhibitory drug. The silencing of LRP-1 was also associated with decreased cholesterol level. The ABCA-1 expression was higher in GBM than LGA and NB (p-value 0.011 and <0.001), however there was no significant association with other parameters. LRP-1 showed a positive correlation with ABCA-1 and associated with decreased expression with LRP-1 knock-down in-vitro. The expression of LRP-1 and ABCA-1 didn't correlate with overall survival in GBMs. Hence, LRP-1 is crucial for the tumor cells' survival and aggressive biological behavior which is maintain through the regulation of high intracellular cholesterol import. Its expression is significantly higher in GBMs and also implicated in the regulation of ABCA-1 expression. Considering its immune-positivity only in the neoplastic cell and strong positivity in GBM it may be a useful adjunct to the diagnosis. For the first time, the present study emphasized its role as a potential therapeutic target in the form of RAP which is presently being used in other neurological diseases under clinical trials.

Development of Brain-Tumor-Targeted Benzothiazole-Based Boron Complex for Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) is a precision treatment technology that ideally damages only boron-accumulating cells. The effectiveness of BNCT depends on the amount of boron in the tumor cells and the concentration ratio between normal and tumor tissues. Therefore, for successful brain-tumor treatment using BNCT, it is essential to develop a drug with high blood-brain barrier (BBB) permeability and high tumor accumulation. The benzothiazole-based boron complex 4-(benzo[d]thiazol-2-yl)phenylboronic acid (BTPB) is a hydrophobic, low-molecular-weight compound that has shown high BBB permeability and brain accumulation. The highest boron concentration of BTPB is 36.11 ± 2.73 μg/g (at 1 h post-injection) in the brain, and the highest brain/blood ratio is 3.94 ± 0.46 (at 2 h post-injection), which is sufficient for the BNCT drug condition. In addition, BTPB showed good tumor-targeting ability in vivo in a U87MG glioma tumor model. In this study, we conducted a biological evaluation of BTPB compared to boronophenylalanine as a novel drug for BNCT.

Extraction, purification and anti-cancer activity of curcumin

Turmeric has long been used as a strong anti-inflammatory in Indian drug systems. Turmeric is rich in curcuminoids that have different chemical, physico-chemical properties. Current work reports exraction of curcuminoids, curcumin using the Soxhlet extractor. Purification and quantification of curcumin is performed by chromatography. The yield percentage of curcumin reported 4.09% by the Soxhlet extraction method. Different solvent were used for extraction, among them acetone extract was with high yield of curcumin. Individual curcumin extract analysed using UV-VIS Spectroscopy and HPLC. Our results showed that the Salem turmeric contains highest percentage of curcumin. The in vitroMTT assay on the U87MG glioma cell line demanstrated anti-cancer activity of isolated curcumin.

Targeted Alpha Therapy of Glioma Using 211At-Labeled Heterodimeric Peptide Targeting Both VEGFR and Integrins.

Targeted radionuclide therapy based on α-emitters plays an increasingly important role in cancer treatment. In this study, we proposed to apply a heterodimeric peptide (iRGD-C6-lys-C6-DA7R) targeting both VEGFR and integrins as a new vector for 211At radiolabeling to obtain high-performance radiopharmaceuticals with potential in targeted alpha therapy (TAT). An astatinated peptide, iRGD-C6-lys(211At-ATE)-C6-DA7R, was prepared with a radiochemical yield of ∼45% and high radiochemical purity of >95% via an electrophilic radioastatodestannylation reaction. iRGD-C6-lys(211At-ATE)-C6-DA7R showed good stability in vitro and high binding ability to U87MG (glioma) cells. Systematic in vitro antitumor investigations involving cytotoxicity, apoptosis, distribution of the cell cycle, and reactive oxygen species (ROS) clearly demonstrated that 211At-labeled heterodimeric peptides could significantly inhibit cell viability, induce cell apoptosis, arrest the cell cycle in G2/M phase, and increase intracellular ROS levels in a dose-dependent manner. Biodistribution revealed that iRGD-C6-lys(211At-ATE)-C6-DA7R had rapid tumor accumulation and fast normal tissue/organ clearance, which was mainly excreted through the kidneys. Moreover, in vivo therapeutic evaluation indicated that iRGD-C6-lys(211At-ATE)-C6-DA7R was able to obviously inhibit tumor growth and prolong the survival of mice bearing glioma xenografts without notable toxicity to normal organs. All these results suggest that TAT mediated by iRGD-C6-lys(211At-ATE)-C6-DA7R can provide an effective and promising strategy for the treatment of glioma and some other tumors.

Reduced PTCH2 expression is associated with glioma development through its regulation of the PTEN/AKT signaling pathway

Mutations in the human protein patched homolog (PTCH) gene have been demonstrated to be associated with cancer development in several types of malignancy. However, the underlying mechanism of PTCH-associated cancer development remains poorly understood, to the best of our knowledge. In the present study, the expression of PTCH2 in glioma tumor tissues from The Cancer Genome Atlas (TCGA) database and clinical patients with glioma were measured. Reduced expression levels of PTCH2 were observed in patients with glioma with poor prognose. In vitro, overexpression of PTCH2 significantly suppressed the proliferation and invasion of the glioma cell lines, LN229 and U87-MG. Mechanistically, PTCH2 upregulated the expression of tumor suppressor PTEN, thereby leading to the suppression of pro-survival AKT signals in glioma. Reduced expression of PTEN and enhanced expression of AKT promoted glioma development in vitro and in vivo. Blockade of PTCH2/AKT signals efficiently strengthened the anticancer effects of chemotherapy and prolonged the survival time in tumor-bearing mice, which provided a novel insight into potential treatment strategies for glioma in the clinic.

Anti-Proliferative Potential of Quercetin Loaded Polymeric Mixed Micelles on Rat C6 and Human U87MG Glioma Cells.

Quercetin (Qu) is a natural flavonoid present in many commonly consumed food items and is also identified as a potential anticancer agent. The present study evaluates the Qu-loaded polymeric mixed micelles (Qu-PMMs) against C6 and U87MG glioma cell lines. The Box–Behnken Design (BBD) was employed to study the influence of independent variables such as Soluplus, Vitamin-E polyethyleneglycol-1000 succinate (E-TPGS), and poloxamer 407 concentrations on dependent variables including particle size (PS), polydispersity index (PDI), and percentage entrapment efficiency (%EE) of the prepared Qu-PMMs. The Qu-PMMs were further characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and were assessed for in vitro drug release, effect on cell viability, migration, cellular uptake, and apoptosis assays. The PS, PDI, and % EE of the optimized PMMs were 107.16 ± 1.06 nm, 0.236 ± 0.053, and 77.46 ± 1.94%, respectively. The FTIR and XRD revealed that the Qu was completely entrapped inside the PMMs. The SEM analysis confirmed the spherical shape of micelles. The in vitro cell viability study showed that the Qu-PMMs had 1.7 times higher cytotoxicity against C6 and U87MG cells than Qu pure drug (Qu-PD). Furthermore, Qu-PMMs demonstrated superior cellular uptake, inhibited migration, and induced apoptosis when tested against C6 and U87MG cells than pure Qu. Thus, the polymeric mixed micelle (PMMs) enhanced the therapeutic effect of Qu and can be considered an effective therapeutic strategy to treat Glioma.

Directed cell migration towards softer environments.

How cells sense tissue stiffness to guide cell migration is a fundamental question in development, fibrosis and cancer. Although durotaxis-cell migration towards increasing substrate stiffness-is well established, it remains unknown whether individual cells can migrate towards softer environments. Here, using microfabricated stiffness gradients, we describe the directed migration of U-251MG glioma cells towards less stiff regions. This 'negative durotaxis' does not coincide with changes in canonical mechanosensitive signalling or actomyosin contractility. Instead, as predicted by the motor-clutch-based model, migration occurs towards areas of 'optimal stiffness', where cells can generate maximal traction. In agreement with this model, negative durotaxis is selectively disrupted and even reversed by the partial inhibition of actomyosin contractility. Conversely, positive durotaxis can be switched to negative by lowering the optimal stiffness by the downregulation of talin-a key clutch component. Our results identify the molecular mechanism driving context-dependent positive or negative durotaxis, determined by a cell's contractile and adhesive machinery.