Demonstrating a Filter-Free Wavelength Sensor with Double-Well Structure and Its Application.

This study proposed a filter-free wavelength sensor with a double-well structure for detecting fluorescence without an optical filter. The impurity concentration was optimized and simulated to form a double-well-structured sensor, of which the result was consistent with the fabricated sensor. Furthermore, we proposed a novel wavelength detection method using the current ratio based on the silicon absorption coefficient. The results showed that the proposed method successfully detected single wavelengths in the 460-800 nm range. Additionally, we confirmed that quantification was possible using the current ratio of the sensor for a relatively wide band wavelength, such as fluorescence. Finally, the fluorescence that was emitted from the reagents ALEXA488, 594, and 680 was successfully identified and quantified. The proposed sensor can detect wavelengths without optical filters, which can be used in various applications in the biofield, such as POCT as a miniaturized wavelength detection sensor.

Selective Etching of Si versus Si1-xGex in Tetramethyl Ammonium Hydroxide Solutions with Surfactant.

We investigated the selective etching of Si versus Si1−xGex with various Ge concentrations (x = 0.13, 0.21, 0.30, 0.44) in tetramethyl ammonium hydroxide (TMAH) solution. Our results show that the Si1−xGex with a higher Ge concentration was etched slower due to the reduction in the Si(Ge)−OH bond. Owing to the difference in the etching rate, Si was selectively etched in the Si0.7Ge0.3/Si/Si0.7Ge0.3 multi-layer. The etching rate of Si depends on the Si surface orientation, as TMAH is an anisotropic etchant. The (111) and (010) facets were formed in TMAH, when Si was laterally etched in the <110> and <100> directions in the multi-layer, respectively. We also investigated the effect of the addition of Triton X-100 in TMAH on the wet etching process. Our results confirmed that the presence of 0.1 vol% Triton reduced the roughness of the etched Si and Si1−xGex surfaces. Moreover, the addition of Triton to TMAH could change the facet formation from (010) to (011) during Si etching in the <100>-direction. The facet change could reduce the lateral etching rate of Si and consequently reduce selectivity. The decrease in the layer thickness also reduced the lateral Si etching rate in the multi-layer.

A Multimodal Sensing Device for Simultaneous Measurement of Dissolved Oxygen and Hydrogen Ions by Monolithic Integration of FET-Based Sensors.

We examined the possibility of measuring dissolved oxygen by using a potentiometric solid-state semiconductor sensor. Thin films of tin (IV) oxide (SnO2) are widely used in oxygen gas sensors. However, their ability to detect dissolved oxygen (DO) in solutions is still unknown. In this paper, we present a method for investigating the dissolved oxygen-sensing properties of SnO2 thin films in solutions by fabricating a SnO2-gate field-effect transistor (FET). A similarly structured hydrogen ion-sensitive silicon nitride (Si3N4)-gate FET was fabricated using the same method. The transfer characteristics and sensitivities were experimentally obtained and compared. The transfer characteristics of the FET show a shift in threshold voltage in response to a decrease in DO concentration. The SnO2-gate FET exhibited a sensitivity of 4 mV/ppm, whereas the Si3N4-gate FET showed no response to DO. Although the SnO2-gate FET responds to pH changes in the solution, this sensitivity issue can be eliminated by using a Si3N4-gate FET, which is capable of selectively sensing hydrogen ions without DO sensitivity. The experimental results indicate the promising properties of SnO2 thin films for multimodal sensing applications.

Bio-Interface on Freestanding Nanosheet of Microelectromechanical System Optical Interferometric Immunosensor for Label-Free Attomolar Prostate Cancer Marker Detection.

Various biosensors that are based on microfabrication technology have been developed as point-of-care testing devices for disease screening. The Fabry-Pérot interferometric (FPI) surface-stress sensor was developed to improve detection sensitivity by performing label-free biomarker detection as a nanomechanical deflection of a freestanding membrane to adsorb the molecules. However, chemically functionalizing the freestanding nanosheet with excellent stress sensitivity for selective molecular detection may cause the surface chemical reaction to deteriorate the nanosheet quality. In this study, we developed a minimally invasive chemical functionalization technique to create a biosolid interface on the freestanding nanosheet of a microelectromechanical system optical interferometric surface-stress immunosensor. For receptor immobilization, glutaraldehyde cross-linking on the surface of the amino-functionalized parylene membrane reduced the shape variation of the freestanding nanosheet to 1/5-1/10 of the previous study and achieved a yield of 95%. In addition, the FPI surface-stress sensor demonstrated molecular selectivity and concentration dependence for prostate-specific antigen with a dynamic range of concentrations from 100 ag/mL to 1 µg/mL. In addition, the minimum limit of detection of the proposed sensor was 2,000,000 times lower than that of the conventional nanomechanical cantilevers.

CMOS-Based Redox-Type Label-Free ATP Image Sensor for In Vitro Sensitive Imaging of Extracellular ATP.

Adenosine 5'-triphosphate (ATP) plays a crucial role as an extracellular signaling molecule in the central nervous system and is closely related to various nerve diseases. Therefore, label-free imaging of extracellular ATP dynamics and spatiotemporal analysis is crucial for understanding brain function. To decrease the limit of detection (LOD) of imaging extracellular ATP, we fabricated a redox-type label-free ATP image sensor by immobilizing glycerol-kinase (GK), L-α-glycerophosphate oxidase (LGOx), and horseradish peroxidase (HRP) enzymes in a polymer film on a gold electrode-modified potentiometric sensor array with a 37.3 µm-pitch. Hydrogen peroxide (H2O2) is generated through the enzymatic reactions from GK to LGOx in the presence of ATP and glycerol, and ATP can be detected as changes in its concentration using an electron mediator. Using this approach, the LOD for ATP was 2.8 µM with a sensitivity of 77 ± 3.8 mV/dec., under 10 mM working buffers at physiological pH, such as in in vitro experiments, and the LOD was great superior 100 times than that of the hydrogen ion detection-based image sensor. This redox-type ATP image sensor may be successfully applied for in vitro sensitive imaging of extracellular ATP dynamics in brain nerve tissue or cells.

Label-free attomolar protein detection using a MEMS optical interferometric surface-stress immunosensor with a freestanding PMMA/parylene-C nanosheet.

We demonstrated an optical interferometer-based surface-stress immunosensor using freestanding polymethyl methacrylate (PMMA)/parylene-C nanosheet with high sensitivity for detection of biomolecules. PMMA/parylene-C nanosheets were transferred onto a silicon substrate with microcavities to fabricate freestanding submicron-thick membrane with a sealed cavity structure. The adhesive force between the transferred parylene-C and binder parylene-C layer was measured to be 1.06-2.4 N/10 mm by tape test. Evading Debye shielding, these nanomechanical sensors allow detection of the adsorption on the membrane surface through changes in surface stress transduced by the electric charge. We optimized the density of receptors and mode of immobilization for high sensitivity. To evaluate the selectivity of the sensor, membrane deflections induced by various proteins were measured and the spectral shifts showed high selectivity only for the target antigen. The minimum limit of detection (LOD) of the sensor for human serum albumin antigen was 0.1-1 fg/mL (1.5-15 aM), which was 20,000 times lower than that of the conventional micro-cantilever sensor.

A ppm Ethanol Sensor Based on Fabry-Perot Interferometric Surface Stress Transducer at Room Temperature.

Disease screening by exhaled breath diagnosis is less burdensome for patients, and various devices have been developed as promising diagnostic methods. We developed a microelectromechanical system (MEMS) optical interferometric surface stress sensor to detect volatile ethanol gas at room temperature (26~27 °C) with high sensitivity. A sub-micron air gap in the optical interferometric sensor reduces interference orders, leading to increased spectral response associated with nanomechanical deflection caused by ethanol adsorption. The sub-micron cavity was embedded in a substrate using a transfer technique of parylene-C nanosheet. The sensor with a 0.4 µm gap shows a linear stable reaction, with small standard deviations, even at low ethanol gas concentrations of 5-110 ppm and a reversible reaction to the gas concentration change. Furthermore, the possibility of detecting sub-ppm ethanol concentration by optimizing the diameter and thickness of the deformable membrane is suggested. Compared with conventional MEMS surface stress gas sensors, the proposed optical interferometric sensor demonstrated high-sensitivity gas detection with exceeding the detection limit by two orders of magnitude while reducing the sensing area.

Quasicrystalline phase-change memory.

Phase-change memory utilizing amorphous-to-crystalline phase-change processes for reset-to-set operation as a nonvolatile memory has been recently commercialized as a storage class memory. Unfortunately, designing new phase-change materials (PCMs) with low phase-change energy and sufficient thermal stability is difficult because phase-change energy and thermal stability decrease simultaneously as the amorphous phase destabilizes. This issue arising from the trade-off relationship between stability and energy consumption can be solved by reducing the entropic loss of phase-change energy as apparent in crystalline-to-crystalline phase-change process of a GeTe/Sb2Te3 superlattice structure. A paradigm shift in atomic crystallography has been recently produced using a quasi-crystal, which is a new type of atomic ordering symmetry without any linear translational symmetry. This paper introduces a novel class of PCMs based on a quasicrystalline-to-approximant crystalline phase-change process, whose phase-change energy and thermal stability are simultaneously enhanced compared to those of the GeTe/Sb2Te3 superlattice structure. This report includes a new concept that reduces entropic loss using a quasicrystalline state and takes the first step in the development of new PCMs with significantly low phase-change energy and considerably high thermal stability.

PIN1 transcript variant 2 acts as a long non-coding RNA that controls the HIF-1-driven hypoxic response.

The transcription factor HIF-1 induces the expression of genes that are essential for cell survival and oxygen homeostasis in hypoxic conditions. The prolyl isomerase Pin1 plays a role in the regulation of HIF-1α. However, the mechanism by which Pin1 controls HIF-1α remains controversial. Surprisingly, we here show that a PIN1 transcript downregulates HIF-1α as a long non-coding RNA. Pin1-silencing siRNAs augmented the hypoxia-induced expression of HIF-1α, thereby upregulating the expression of HIF-1 target genes. However, the overexpression of Pin1 protein did not inhibit the hypoxic expression of HIF-1α. Pin1 restoration in Pin1-depleted cells also failed to reverse the induction of HIF-1α by Pin1 knockdown. Unexpectedly, HIF-1α was found to be induced by both siRNAs for PIN1 transcript variants 1/2 and that for PIN1 transcript variants 2/3, indicating that the PIN1 transcript variant 2 (PIN1-v2) is responsible for HIF-1α induction. Mechanistically, PIN1-v2, which is classified as a long non-coding RNA due to early termination of translation, was evaluated to inhibit the transcription of HIF1A gene. In conclusion, PIN1-v2 may function in balancing the HIF-1-driven gene expression under hypoxia.

Spinal anesthesia and postoperative epidural analgesia in a patient with congenital central hypoventilation syndrome -a case report.

Background: Congenital central hypoventilation syndrome (CCHS) is a rare disorder characterized by alveolar hypoventilation and autonomic dysregulation. Patients with CCHS have adequate ventilation while awake but exhibit hypoventilation while asleep. More severely affected patients exhibit hypoventilation both when awake and when asleep. Case: Here, we report a case of successful spinal anesthesia and postoperative epidural analgesia in a patient with CCHS who underwent orthostatic surgery. Conclusions: In patients with CCHS, anesthesia is used with the goal of minimizing respiratory depression to avoid prolonged mechanical ventilation. Regional anesthesia should be considered where appropriate. Continuous oxygen saturation and end-tidal carbon dioxide monitoring must be available.

Diacetoxyscirpenol as a new anticancer agent to target hypoxia-inducible factor 1.

Hypoxia activates hypoxia-inducible factor 1, which promotes the progression of malignancy by stimulating angiogenesis and by augmenting the ability of tumors to survive. Thus, HIF-1 is one of the most compelling targets for treating cancers. The aim of this study was to find a small molecule that inhibits HIF-1 under hypoxia in cancer cells. 7,280 compounds in a chemical library were tested in a cancer cell line expressing luciferase HIF-dependently. Through three rounds of screening, we finally picked up a compound that originates from a marine bacterium parasitizing red alga. The antibiotic potently inhibited HIF-1 expression and its transcriptional activity in cancer cells exposed to hypoxia. Through two-step fractionation, diacetoxyscirpenol was purified and identified as a HIF-inhibiting ingredient. Mechanistically, diacetoxyscirpenol inhibits the synthesis of HIF-1α protein and also interferes with the dimerization of HIF-1α and ARNT. It attenuates HIF-mediated gene expression in cancer cells exposed to hypoxia, and by doing so reduces tumorigenic and angiogenic potentials of cancer cells. More importantly, diacetoxyscirpenol retarded tumor growth in mice, and reduced HIF-1α expression and vascular formation in the tumors. Overall, diacetoxyscirpenol is considered a potential drug deregulating the HIF-1 signaling pathway, and it could be beneficially employed for treating malignant tumors with hypoxic microenvironment.

Distinct effects of SIRT1 in cancer and stromal cells on tumor promotion.

The lysyl deacetylase SIRT1 acts as a metabolic sensor in adjusting metabolic imbalance. To explore the role of SIRT1 in tumor-stroma interplay, we designed an in vivo tumor model using SIRT1-transgenic mice. B16F10 mouse melanoma grew more quickly in SIRT1-transgenic mice than in wild-type mice, whereas SIRT1-overexpressing one grew slowly in both mice. Of human tumors, SIRT1 expression in stromal fibroblasts was found to correlate with poor prognosis in ovarian cancer. B16F10 and human ovarian cancer (SKOV3 and SNU840) cells were more proliferative in co-culture with SIRT1-overexpressiong fibroblasts. In contrast, SIRT1 within cancer cells has a negative effect on cell proliferation. In conditioned media from SIRT1-overexpressing fibroblasts, matrix metalloproteinase-3 (MMP3) was identified in cytokine arrays to be secreted from fibroblasts SIRT1-dependently. Fibroblast-derived MMP3 stimulated cancer cell proliferation, and such a role of MMP3 was also demonstrated in cancer/fibroblast co-grafts. In conclusion, SIRT1 plays differential roles in cancer and stromal cells. SIRT1 in stromal cells promotes cancer growth by producing MMP3, whereas SIRT1 in cancer cells inhibits growth via an intracellular event. The present study provides a basis for setting new anticancer strategies targeting SIRT1.

PRMT5 is essential for the eIF4E-mediated 5'-cap dependent translation.

It is becoming clear that PRMT5 plays essential roles in cell cycle progression, survival, and responses to external stresses. However, the precise mechanisms underlying such roles of PRMT5 have not been clearly understood. Previously, we have demonstrated that PRMT5 participates in cellular adaptation to hypoxia by ensuring 5'-cap dependent translation of HIF-1α. Given that c-Myc and cyclin D1 expressions are also tightly regulated in 5'-cap dependent manner, we here tested the possibility that PRMT5 promotes cell proliferation by increasing de novo syntheses of the oncoproteins. c-Myc and cyclin D1 were found to be noticeably downregulated by PRMT5 knock-down. A RNA immunoprecipitation analysis, which can identify RNA-protein interactions, showed that PRMT5 is required for the interaction among eIF4E and 5'-UTRs of HIF-1α, c-Myc and cyclin D1 mRNAs. In addition, PRMT5 knock-down inhibited cell proliferation by inducing cell cycle arrest at the G1 phase. More importantly, ectopic expression of eIF4E significantly rescued the cell cycle progression and cell proliferation even in PRMT5-deficeint condition. Based on these results, we propose that PRMT5 determines cell fate by regulating 5'-cap dependent translation of proteins essential for proliferation and survival.

Geldanamycin attenuates 3­nitropropionic acid­induced apoptosis and JNK activation through the expression of HSP 70 in striatal cells.

Although selective striatal cell death is a characteristic hallmark in the pathogenesis of Huntington's disease (HD), the underlying mechanism of striatal susceptibility remains to be clarified. Heat shock proteins (HSPs) have been reported to suppress the aggregate formation of mutant huntingtin and concurrent striatal cell death. In a previous study, we observed that heat shock transcription factor 1 (HSF1), a major transcription factor of HSPs, significantly attenuated 3­nitropropionic acid (3NP)­induced reactive oxygen species (ROS) production and apoptosis through the expression of HSP 70 in striatal cells. To investigate the differential roles of HSPs in 3NP­induced striatal cell death, the effect of geldanamycin (GA), an HSP 90 inhibitor, was examined in 3NP­stimulated striatal cells. GA significantly attenuated 3NP­induced striatal apoptosis and ROS production with an increased expression of HSP 70. Triptolide (TL), an HSP 70 inhibitor, abolished GA­mediated protective effects in 3NP­stimulated striatal cells. To understand the underlying mechanism by which GA­mediated HSP 70 protects striatal cells against 3NP stimulation, the involvement of various signaling pathways was examined. GA significantly attenuated 3NP­induced c­Jun N­terminal kinase (JNK) phosphorylation and subsequent c­Jun phosphorylation in striatal cells. Taken together, the present study demonstrated that GA exhibits protective properties against 3NP­induced apoptosis and JNK activation via the induction of HSP 70 in striatal cells, suggesting that expression of HSP 70 may be a valuable therapeutic target in the treatment of HD.

SIRT1 and AMPK mediate hypoxia-induced resistance of non-small cell lung cancers to cisplatin and doxorubicin.

SIRT1 is an NAD(+)-dependent protein deacetylase induced by metabolic stresses, such as nutrition or oxygen deprivation. Although SIRT1 contributes to aging and metabolic disorders, its role in cancer progression and therapeutic responses remains controversial. Because hypoxia occurs widely in solid tumors, where it provokes drug resistance, we investigated the involvement of SIRT1 in hypoxia-induced chemoresistance. SIRT1 was downregulated in a panel of non-small cell lung carcinoma (NSCLC) cells exposed to hypoxia for 48 hours. The master metabolic kinase AMP-activated protein kinase (AMPK) was inactivated under the same conditions, likely due to attenuation of the SIRT1/LKB1-mediated AMPK activation process. Notably, hypoxic inactivation of this SIRT1-AMPK pathway led to cisplatin and doxorubicin resistance. Mechanistic investigations suggested that this pathway supported the cytotoxic response to cisplatin and doxorubicin by licensing an apoptotic process controlled by mitochondria. We confirmed the involvement of this pathway in a mouse xenograft model of human NSCLC. Furthermore, we demonstrated that a SIRT1 activator SRT1720 augmented the antitumor effects of cisplatin, and these effects could be blocked by administration of an AMPK inhibitor compound C. Taken together, our results offer preclinical proof-of-concept to target the SIRT1-AMPK pathway as a strategy to overcome hypoxia-induced chemoresistance in NSCLC.

Disulfiram deregulates HIF-α subunits and blunts tumor adaptation to hypoxia in hepatoma cells.

AIM: Disulfiram is an aldehyde dehydrogenase inhibitor that was used to treat alcoholism and showed anticancer activity, but its anticancer mechanism remains unclear. The aim of this study was to investigate the effects of disulfiram on the hypoxia-inducible factor (HIF)-driven tumor adaptation to hypoxia in vitro. METHODS: Hep3B, Huh7 and HepG2 hepatoma cells were incubated under normoxic (20% O2) or hypoxic (1% O2) conditions for 16 h. The expression and activity of HIF-1α and HIF-2α proteins were evaluated using immunoblotting and luciferase reporter assay, respectively. Semi-quantitative RT-PCR was used to analyze HIF-mediated gene expression. Endothelial tubule formation assay was used to evaluate the anti-angiogenic effect. RESULTS: Hypoxia caused marked expression of HIF-1α and HIF-1α in the 3 hepatoma cell lines, dramatically increased HIF activity and induced the expression of HIF downstream genes (EPO, CA9, VEGF-A and PDK1) in Hep3B cells. HIF-2α expression was positively correlated with the induction of hypoxic genes (CA9, VEGF-A and PDK1). Moreover, hypoxia markedly increased VEGF production and angiogenic potential of Hep3B cells. Disulfiram (0.3 to 2 µmol/L) inhibited hypoxia-induced gene expression and HIF activity in a dose-dependent manner. Disulfiram more effectively suppressed the viability of Hep3B cells under hypoxia, but it did not affect the cell cycle. Overexpression of HIF-2α in Hep3B cells reversed the inhibitory effects of disulfiram on hypoxia-induced gene expression and cell survival under hypoxia. CONCLUSION: Disulfiram deregulates the HIF-mediated hypoxic signaling pathway in hepatoma cells, which may contribute to its anticancer effect. Thus, disulfiram could be used to treat solid tumors that grow in a HIF-dependent manner.

Heat shock transcription factor-1 suppresses apoptotic cell death and ROS generation in 3-nitropropionic acid-stimulated striatal cells.

Striatal neuronal cell death is one of the pathological features of Huntington's disease (HD). Overexpression of some heat shock proteins (HSPs) has been reported to suppress the aggregate formation of mutant huntingtin and concurrent cell death. Heat shock transcription factor-1 (HSF 1), a major transcription factor of HSPs, has also been reported to be increased in HD models. However, the exact role of HSF 1 in the pathogenesis of HD has not been clearly elucidated. 3-Nitropropionic acid (3NP), an irreversible inhibitor of the mitochondrial complex II, induces selective damage to the striatum in animals and produces clinical features of HD. To investigate roles of HSF 1 on 3NP-induced oxidative stress, HSF 1 was transiently overexpressed in striatal cells. Expression of HSF 1 significantly attenuated 3NP-induced apoptotic striatal cell death and resulted in increased expression of HSP 70. Furthermore, expression of HSF 1 significantly attenuated 3NP-induced intracellular reactive oxygen species (ROS) generation. Taken together, the present study clearly demonstrates that HSF 1 attenuates 3NP-induced apoptotic striatal cell death and ROS generation, possibly through HSP70 expression, suggesting that HSF 1 might be a valuable therapeutic target in the treatment of HD.

Protein arginine methyltransferase 5 is an essential component of the hypoxia-inducible factor 1 signaling pathway.

Protein arginine methyltransferase 5 (PRMT5) is an enzyme that transfers one or two methyl groups to the arginine residues of histones or non-histone proteins, and that plays critical roles in cellular processes as diverse as receptor signaling and gene expression. Furthermore, PRMT5 is highly expressed in tumors, where it may be associated with tumor growth. Although much research has been conducted on PRMT5, little is known regarding its role in adaption to hypoxia. As hypoxia-inducible factor 1 (HIF-1) is a key player in hypoxic response, we examined the possible involvement of PRMT5 in the HIF-1 signaling pathway. Of the siRNAs targeting PRMT1-8, only PRMT5 siRNA attenuated the hypoxic induction of HIF-1α in A549 cells, and this result was reproducible in all three cancer cell lines examined. PRMT5 knock-down also repressed the promoter activities and the transcript levels of HIF-1-governed genes. Mechanistically, de novo synthesis of HIF-1α protein was reduced in PRMT5-knocked-down A549 cells, and this was rescued by PRMT5 restoration. In contrast, HIF-1α transcription, RNA processing, and protein stability were unaffected by PRMT5 knock-down. Furthermore, PRMT5 was found to be essential for the HIF-1α translation initiated by the 5' UTR of HIF-1α mRNA. Given our results and previous reports, we believe that PRMT5 probably promotes tumor growth by stimulating cell proliferation and by participating in the construction of a tumor-favorable microenvironment via HIF-1 activation.

Suppression of aggregate formation of mutant huntingtin potentiates CREB-binding protein sequestration and apoptotic cell death.

Although aggregates of mutant huntingtin are a pathological hallmark of Huntington's disease (HD), the role of inclusions in the pathogenesis remains inconclusive. Sequestration of CBP into mutant huntingtin has been reported to play a significant role in the pathogenesis of HD. However, whether aggregate formation of mutant huntingtin is necessary for the sequestration of CBP is not fully elucidated. In the present study, YFP was linked into either N- or C-terminus of exon 1 huntingtin to modulate the aggregation propensity of huntingtin. Efficient aggregation was observed with C-terminally YFP-tagged huntingtin (MT-YFP) whereas N-terminally YFP-tagged mutant huntingtin (YFP-MT) exhibited significantly attenuated aggregation frequency. The sequestration of CBP and apoptosis were significantly increased with YFP-MT. Microarray study showed transcriptional changes favoring apoptosis. Furthermore, expression of PGC1-α was significantly decreased with YFP-MT. The data strongly demonstrate that microscopically non-aggregate form of mutant huntingtin might exert essential pathogenic role of mutant huntingtin in HD.

Thrombin-induced Migration and Matrix Metalloproteinase-9 Expression Are Regulated by MAPK and PI3K Pathways in C6 Glioma Cells.

Glioblastoma multiforme is one of the most common and aggressive tumors in central nervous system. It often possesses characteristic necrotic lesions with hemorrhages, which increase the chances of exposure to thrombin. Thrombin has been known as a regulator of MMP-9 expression and cancer cell migration. However, the effects of thrombin on glioma cells have not been clearly understood. In the present study, influences of thrombin on glioma cell migration were examined using Boyden chamber migration assay and thrombin-induced changes in MMP-9 expression were measured using zymography, semi-quantitative RT-PCR, and Western blotting. Furthermore, underlying signaling pathways by which thrombin induces MMP-9 expression were examined. Thrombin-induced migration and MMP-9 expression were significantly potentiated in the presence of wortmannin, a PI3K inhibitor, whereas MAPK inhibitors suppressed thrombin-induced migration and MMP-9 expression in C6 glioma cells. The present data strongly demonstrate that MAPK and PI3K pathways evidently regulate thrombin-induced migration and MMP-9 expression of C6 glioma cells. Therefore, the control of these pathways might be a beneficial therapeutic strategy for treatment of invasive glioblastoma multiforme.