The role of fascin in the migration and invasiveness of malignant glioma cells

The in vitro anti-cancer synergy of neurokinin-1 receptor antagonist, aprepitant, and 5-aminolevulinic acid in glioblastoma

Glioblastoma multiforme (GBM) is the most malignant type of cerebral neoplasm in adults with a poor prognosis. Currently, combination therapy with different anti-cancer agents is at the forefront of GBM research. Hence, this study aims to evaluate the potential anti-cancer synergy of a clinically approved neurokinin-1 receptor antagonist, aprepitant, and 5-aminolevulinic acid (5-ALA), a prodrug that elicits fluorescent porphyrins in gliomas on U-87 human GBM cells. We found that aprepitant and 5-ALA effectively inhibited GBM cell viability. The combinatorial treatment of these drugs exerted potent synergistic growth inhibitory effects on GBM cells. Moreover, aprepitant and 5-ALA induced apoptosis and altered the levels of apoptotic genes (up-regulation of Bax and P53 along with downregulation of Bcl-2). Furthermore, aprepitant and 5-ALA increased the accumulation of protoporphyrin IX, a highly pro-apoptotic and fluorescent photosensitizer. Aprepitant and 5-ALA significantly inhibited GBM cell migration and reduced matrix metalloproteinases (MMP-2 and MMP-9) activities. Importantly, all these effects were more prominent following aprepitant-5-ALA combination treatment than either drug alone. Collectively, the combination of aprepitant and 5-ALA leads to considerable synergistic anti-proliferative, pro-apoptotic, and anti-migratory effects on GBM cells and provides a firm basis for further evaluation of this combination as a novel therapeutic approach for GBM.

A computational modeling of invadopodia protrusion into an extracellular matrix fiber network

Invadopodia are dynamic actin-rich membrane protrusions that have been implicated in cancer cell invasion and metastasis. In addition, invasiveness of cancer cells is strongly correlated with invadopodia formation, which are observed during extravasation and colonization of metastatic cancer cells at secondary sites. However, quantitative understanding of the interaction of invadopodia with extracellular matrix (ECM) is lacking, and how invadopodia protrusion speed is associated with the frequency of protrusion-retraction cycles remains unknown. Here, we present a computational framework for the characterization of invadopodia protrusions which allows two way interactions between intracellular branched actin network and ECM fibers network. We have applied this approach to predicting the invasiveness of cancer cells by computationally knocking out actin-crosslinking molecules, such as α-actinin, filamin and fascin. The resulting simulations reveal distinct invadopodia dynamics with cycles of protrusion and retraction. Specifically, we found that (1) increasing accumulation of MT1-MMP at tips of invadopodia as the duration of protrusive phase is increased, and (2) the movement of nucleus toward the leading edge of the cell becomes unstable as duration of the retractile phase (or myosin turnover time) is longer than 1 min.

Treatment of kidney clear cell carcinoma, lung adenocarcinoma and glioblastoma cell lines with hydrogels made of DNA nanostars

Overcoming the systemic administration of chemotherapy to reduce drug toxicity and the application of personalised medicine are two of the major challenges in the treatment of cancer. To this aim,...

Effect of Cadherin-11 Expression on the Prognosis of a Newly Diagnosed Primary Glioblastoma

Background

Cadherin-11, a cell-to-cell adhesion molecule, is associated with higher tumor grade and decreased patient survival. The purpose of this study was to investigate the clinical significance of cadherin-11 expression in the progression and prognosis of a newly diagnosed primary glioblastoma (GBL).

Methods

Between 2007 and 2016, 52 out of 178 patients diagnosed with a GBL and satisfied the following criteria: 1) a new primary GBL, 2) gross-total resection, 3) immunohistochemically-available tissue, and 4) standardized adjuvant treatment.

Results

In terms of staining intensity, the low-intensity cadherin-11 group showed longer progression-free survival (PFS) than the high-intensity cadherin-11 group (median PFS, 12.0 months [95% CI, 11.1–12.9] vs. median PFS, 6.0 months [95% CI, 3.7–8.3]; p<0.001). The low-intensity cadherin-11 group revealed longer overall survival (OS) than the high-intensity cadherin-11 group (median OS, 20.0 months [95% CI, 11.8–16.6] vs. median OS, 15.0 months [95% CI, 11.8–18.2]; p=0.003). The staining intensity of cadherin-11 was a statistically significant factor in PFS and OS in terms of univariate and multivariate analyses (univariate analysis: p<0.001 and p=0.005; multivariate analysis: p<0.001 and p=0.005).

Conclusion

Our clinical study demonstrates high cadherin-11 expression may be associated with poor PFS and OS for a newly diagnosed primary GBL.

Adaptive mechanoproperties mediated by the formin FMN1 characterize glioblastoma fitness for invasion

Glioblastoma are heterogeneous tumors composed of highly invasive and highly proliferative clones. Heterogeneity in invasiveness could emerge from discrete biophysical properties linked to specific molecular expression. We identified clones of patient-derived glioma propagating cells that were either highly proliferative or highly invasive and compared their cellular architecture, migratory, and biophysical properties. We discovered that invasiveness was linked to cellular fitness. The most invasive cells were stiffer, developed higher mechanical forces on the substrate, and moved stochastically. The mechano-chemical-induced expression of the formin FMN1 conferred invasive strength that was confirmed in patient samples. Moreover, FMN1 expression was also linked to motility in other cancer and normal cell lines, and its ectopic expression increased fitness parameters. Mechanistically, FMN1 acts from the microtubule lattice and promotes a robust mechanical cohesion, leading to highly invasive motility.

Probing mechanobiological role of filamin A in migration and invasion of human U87 glioblastoma cells using submicron soft pillars

Filamin A (FLNa) belongs to an actin-binding protein family in binding and cross-linking actin filaments into a three-dimensional structure. However, little attention has been given to its mechanobiological role in cancer cells. Here, we quantitatively investigated the role of FLNa by analyzing the following parameters in negative control (NC) and FLNa-knockdown (KD) U87 glioma cells using submicron pillars (900 nm diameter and 2 μm height): traction force (TF), rigidity sensing ability, cell aspect ratio, migration speed, and invasiveness. During the initial phase of cell adhesion (< 1 h), FLNa-KD cells polarized more slowly than did NC cells, which can be explained by the loss of rigidity sensing in FLNa-KD cells. The higher motility of FLNa-KD cells relative to NC cells can be explained by the high TF exerted by FLNa-KD cells when compared to NC cells, while the higher invasiveness of FLNa-KD cells relative to NC cells can be explained by a greater number of filopodia in FLNa-KD cells than in NC cells. Our results suggest that FLNa plays important roles in suppressing motility and invasiveness of U87 cells.

Fascin actin-bundling protein 1 in human cancer: promising biomarker or therapeutic target?

Fascin actin-bundling protein 1 (FSCN1) is a highly conserved actin-bundling protein that cross links F-actin microfilaments into tight, parallel bundles. Elevated FSCN1 levels have been reported in many types of human cancers and have been correlated with aggressive clinical progression, poor prognosis, and survival outcomes. The overexpression of FSCN1 in cancer cells has been associated with tumor growth, migration, invasion, and metastasis. Currently, FSCN1 is recognized as a candidate biomarker for multiple cancer types and as a potential therapeutic target. The aim of this study was to provide a brief overview of the FSCN1 gene and protein structure and elucidate on its actin-bundling activity and physiological functions. The main focus was on the role of FSCN1 and its upregulatory mechanisms and significance in cancer cells. Up-to-date studies on FSCN1 as a novel biomarker and therapeutic target for human cancers are reviewed. It is shown that FSCN1 is an unusual biomarker and a potential therapeutic target for cancer.

The Role and Therapeutic Targeting of JAK/STAT Signaling in Glioblastoma

Glioblastoma remains one of the deadliest and treatment-refractory human malignancies in large part due to its diffusely infiltrative nature, molecular heterogeneity, and capacity for immune escape. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway contributes substantively to a wide variety of protumorigenic functions, including proliferation, anti-apoptosis, angiogenesis, stem cell maintenance, and immune suppression. We review the current state of knowledge regarding the biological role of JAK/STAT signaling in glioblastoma, therapeutic strategies, and future directions for the field.

Novel facets of glioma invasion

Malignant gliomas including Glioblastoma (GBM) are characterized by extensive diffuse tumor cell infiltration throughout the brain, which represents a major challenge in clinical disease management. While surgical resection is beneficial for patient outcome, it is well recognized that tumor cells at the invasive front or beyond stay behind and constitute a major source of tumor recurrence. Invasive glioma cells also represent a difficult therapeutic target since they are localized within normal functional brain areas with an intact blood brain barrier (BBB), thereby excluding most systemic drug treatments. Cell movement is mediated via the actin cytoskeleton where corresponding membrane protrusions play essential roles. This review provides an overview of the various paths of glioma cell invasion and underlines the specific aspects of the brain microenvironment. We highlight recent insight into tumor microtubes, neuro-glioma synapses and tumor metabolism which can regulate collective invasion processes. We also focus on the deregulation of actin cytoskeleton-related components in the context of glioma invasion, a deregulation that may be controlled by genomic alterations in tumor cells as well as by various external factors, including extracellular matrix (ECM) components and non-malignant stromal cells. Finally we critically assess the challenges and opportunities for therapeutically targeting glioma cell invasion.

Naringenin Sensitizes Resistant C6 Glioma Cells with a Repressive Impact on the Migrating Ability

Background:

Glioma, the most common form of a malignant brain tumour is characterised by a poor prognosis, which is attributable to its resistance against current therapeutic approaches. Temozolomide (TMZ), a DNA alkylating agent, is the first-line drug for glioma treatment. Long-term treatment using TMZ was reported to culminate in the development of resistance with overexpression of multidrug resistance 1 gene coded protein P-glycoprotein, which in turn releases the drugs from the tumour cells.

Purpose:

Thus, to circumvent such resistance issues, the current study attempted to explore the effect of naringenin (a flavanone) with proven antiglial tumour potential, in mitigating the features of TMZ resistance.

Methods:

Colony-forming assay, invasion assay and scratch wound assay were performed among the groups, namely tumour control (C6), vehicle control (V), naringenin (NGEN)-treated, drug-resistant tumour cells (C6R), and drug resistance cells added with NGEN (C6R+NGEN), to examine the impact of NGEN on migration and invasion. The effect of NGEN on filopodia length and density during cell migration was also studied in addition to the matrix metalloproteinases (MMP-2 and MMP-9) and p-ERK levels.

Results and Conclusion:

NGEN and C6R+NGEN groups had shown significant reduction (P < .01) in length and density of filopodia, colony formation, invasion and wound healing. Further, NGEN could also modify the assessed protein levels (P < .001), which were involved in migration and invasion in sensitive and resistant cells. Our study had provided the first evidence on NGEN-induced enhanced sensitivity against TMZ resistance with profound influence as an antimigratory and anti-invasive agent.

microRNA-605 directly targets SOX9 to alleviate the aggressive phenotypes of glioblastoma multiforme cell lines by deactivating the PI3K/Akt pathway

Background

Aberrant microRNA (miRNA) expression has been widely reported to play a crucial role in the progression and development of glioblastoma (GBM). miR-605 has been identified as a tumor-suppressing miRNA in several types of human cancers. Nevertheless, the expression profile and detailed roles of miR-605 in GBM remain unclear and need to be further elucidated.

Materials and methods

RT-qPCR analysis was utilized for the determination of miR-605 expression in GBM tissues and cell lines. In addition, CCK-8 assay, transwell migration and invasion assays, as well as sub-cutaneous xenograft mouse models were utilized to evaluate the effects of miR-605 upregulation in GBM cells. Notably, the potential mechanisms underlying the activity of miR-605 in the malignant phenotypes of GBM were explored.

Results

We observed that expression of miR-605 was reduced in GBM tissues and cell lines. Decreased miR-605 expression exhibited significant correlation with KPS score. The overall survival rate in GBM patients with low miR-605 expression was lower than that of patients with high miR-605 expression. Increased miR-605 expression suppressed the proliferation, migration, and invasion of U251 and T98 cells. In addition, miR-605 upregulation impaired tumor growth in vivo. Furthermore, SRY-Box 9 (SOX9) was identified as a direct target gene of miR-605 in U251 and T98 cells. SOX9 expression was shown to exhibit an inverse correlation with miR-605 expression in GBM tissues. Moreover, silencing of SOX9 expression mimicked the tumor-suppressing roles of miR-605 in U251 and T98 cells, while SOX9 restoration rescued the suppressive effects of miR-605 overexpression in the same. Notably, miR-605 suppressed the PI3K/Akt pathway in GBM in vitro and in vivo.

Conclusion

These results demonstrated that miR-605 acts as a tumor suppressor in the development of GBM by directly targeting SOX9 and inhibiting the activation of the PI3K/Akt pathway, suggesting its potential role as a therapeutic target for GBM.

The Cytoskeleton-A Complex Interacting Meshwork

The cytoskeleton of animal cells is one of the most complicated and functionally versatile structures, involved in processes such as endocytosis, cell division, intra-cellular transport, motility, force transmission, reaction to external forces, adhesion and preservation, and adaptation of cell shape. These functions are mediated by three classical cytoskeletal filament types, as follows: Actin, microtubules, and intermediate filaments. The named filaments form a network that is highly structured and dynamic, responding to external and internal cues with a quick reorganization that is orchestrated on the time scale of minutes and has to be tightly regulated. Especially in brain tumors, the cytoskeleton plays an important role in spreading and migration of tumor cells. As the cytoskeletal organization and regulation is complex and many-faceted, this review aims to summarize the findings about cytoskeletal filament types, including substructures formed by them, such as lamellipodia, stress fibers, and interactions between intermediate filaments, microtubules and actin. Additionally, crucial regulatory aspects of the cytoskeletal filaments and the formed substructures are discussed and integrated into the concepts of cell motility. Even though little is known about the impact of cytoskeletal alterations on the progress of glioma, a final point discussed will be the impact of established cytoskeletal alterations in the cellular behavior and invasion of glioma.

Human papilloma virus infection and fascin over-expression in squamous cell carcinoma of the cervix

Background: Human papilloma virus (HPV) is involved in development of almost all cervical cancers, mainly through the subversion of cellular mechanisms of growth control. Fascin plays central role in subsequent cell transformation events. Fascin mediates stabilization of parallel actin bundles where cellular protrusions are formed; this represents primary stages of cell migration and metastasis. Immunohistochemical assays have shown up-regulation of fascin expression in many epithelial and non-epithelial neoplasms. Therefore, the aim of this study was to investigate HPV infection and fascin expression in samples of cervical cancer.

Methods: Of 66 patients with confirmed SCC, formalin-fixed specimens, embedded in paraffin blocks were evaluated for HPV infection with nested multiplex polymerase chain reaction (NM-PCR) and for fascin expression with immunohistochemical assays. Statistical analysis was performed using Wilcoxon rank-sum test and SPSS software. A p<0.05 was considered for statistical significance.

Results: Of 66 samples, 52 (78.7%) were found positive for HPV infection and fascin over-expression was shown in all squamous cell carcinoma samples.

Conclusion: This study showed fascin overexpression in squamous cell carcinoma of the cervix which might be involved in metastasis of cancers induced by some types of HPV, hypothetically through attenuation of inter-cellular adhesions, and induction of cell motility

Behaviors of Glioblastoma Cells in in Vitro Microenvironments

Glioblastoma (GBM) is the most malignant and highly aggressive brain tumor. In this study, four types of typical GBM cell lines (LN229, SNB19, U87, U251) were cultured in a microfabricated 3-D model to study their in vitro behaviors. The 3-D in vitro model provides hollow micro-chamber arrays containing a natural collagen interface and thus allows the GBM cells to grow in the 3-D chambers. The GBM cells in this model showed specific properties on the aspects of cell morphology, proliferation, migration, and invasion, some of which were rarely observed before. Furthermore, how the cells invaded into the surrounding ECM and the corresponding specific invasion patterns were observed in details, implying that the four types of cells have different features during their development in cancer. This complex in vitro model, if applied to patient derived cells, possesses the potential of becoming a clinically relevant predictive model.

Long noncoding RNA OIP5-AS1 targets Wnt-7b to affect glioma progression via modulation of miR-410

The present study was undertaken to investigate the underlying mechanisms of long noncoding RNA OIP5-AS1 via regulating miR-410 to modulate Wnt-7b in the progression of glioma. To address this problem, we measured the expression of OIP5-AS1 and miR-410 in glioma tissues by qRT-PCR. Glioma U87 cells were transfected with OIP5-AS1 siRNA or miR-410 inhibitors. The targeting relationships among miR-410, OIP5-AS1 and Wnt-7b were verified by luciferase reporter assays. Western blotting was employed to determine the expression of Wnt-7b/β-catenin pathway-related proteins, while MTT, flow cytometry, Transwell assays and wound-healing assays were used to measure the biological characteristics of glioma cells. The results showed that OIP5-AS1 expression was higher and miR-410 was lower in glioma tissues. Luciferase reporter assays confirmed a targeting relationship between OIP5-AS1 and miR-410, as well as between miR-410 and Wnt-7b. Silencing OIP5-AS1 reduced cell proliferation, invasion and migration of glioma U87 cells and led to depressed expression levels of miR-410, Wnt-7b, p-β-catenin, GSK-3β-pS9, c-Myc and cyclin D1. Furthermore, down-regulation of OIP5-AS1 induced G0/G1 phase cell cycle arrest and apoptosis of glioma cells. Inhibitors of miR-410 abolished the biological effects of OIP5-AS1 siRNA in glioma cells. In vivo, OIP5-AS1 knockdown also inhibited tumor growth. Taken together, this research suggested that silencing OIP5-AS1 may specifically block the Wnt-7b/β-catenin pathway via targeted up-regulating miR-410, thereby inhibiting growth, invasion and migration while promoting apoptosis in glioma cells.

Inhibition of glioblastoma cell invasion by hsa-miR-145-5p and hsa-miR-31-5p co-overexpression in human mesenchymal stem cells

OBJECTIVE

Human bone marrow–derived mesenchymal stem cells (hMSCs) show tropism for brain tumors and may be a useful vehicle for drug or gene delivery to malignant gliomas. Recently, some microRNAs (miRNAs) have been shown to suppress the invasiveness of malignant gliomas.

METHODS

To test their potential to become vehicles for the delivery of miRNA to malignant gliomas, hMSCs were engineered so that hMSC secretion of miRNAs that inhibit glioma cell invasion was enabled without altering the hMSC tropism for glioma cells.

RESULTS

In coculture, hMSCs cotransfected with hsa-miR-145-5p and -31-5p miRNAs showed markedly reduced invasion by U87 glioma cells in a contact-dependent manner both in vitro and ex vivo, with invasion of hMSCs cotransfected with these 2 miRNAs by the U87 cells reduced to 60.7% compared with control cells. According to a Matrigel invasion assay, the tropism of the hMSCs for U87 cells was not affected. In glioma cell lines U251 and LN229, hMSCs exhibited tropism in vivo, and invasion of hMSCs cotransfected with hsa-miR-145-5p and -31-5p was also significantly less than that of control cells. When U87 cells were coimplanted into the striatum of organotypic rat brain slices with hMSCs cotransfected with hsa-miR-145 and -31-5p, the relative invasive area decreased by 37.1%; interestingly, these U87 cells showed a change to a rounded morphology that was apparent at the invasion front. Whole-genome microarray analysis of the expression levels of 58,341 genes revealed that the co-overexpression of hsa-miR-145-5p and -31-5p downregulated FSCN1 expression in U87 cells.

CONCLUSIONS

This study demonstrates that miRNA overexpression in hMSCs can alter the function of glioma cells via contact-dependent transfer. Co-overexpression of multiple miRNAs may be a useful and novel therapeutic strategy. The study results suggest that hMSCs can be applied as a delivery vehicle for miRNAs.

Anti-Migration and Anti-Invasion Effects of Curcumin via Suppression of Fascin Expression in Glioblastoma Cells

Background

The natural compound curcumin was known to inhibit migration and invasion of glioblastoma (GBM) cells. Fascin, a kind of actin-binding proteins, is correlated with migration and invasion of GBM cells. The purpose of this study was to investigate anti-migration and anti-invasion effects of curcumin via suppression of fascin expression in GBM cells.

Methods

U87 cell line was used as an experimental model of GBM. Fascin was quantified by Western blot analysis. And, the signal transducer and activator of transcription 3 (STAT3), known to play an important role in migration and invasion of tumor cells, were analyzed by sandwich-ELISA. Migration and invasion capacities were assessed by attachment, migration and invasion assays. Cellular morphology was demonstrated by immunofluorescence.

Results

At various concentrations of curcumin and exposure times, fascin expression decreased. After temporarily exposure to 10 µM/L curcumin during 6 hours as less invasive concentration and time, fascin expression temporarily decreased at 12 hours (18.4%, p=0.024), and since then recovered. And, the change of phosphrylated STAT3 level also reflected the temporarily decreased pattern of fascin expression at 12 hours (19.7%, p=0.010). Attachment, migration, and invasion capacities consistently decreased at 6, 12, and 24 hours. And, immunofluorescence showed the change of shape and the reduction of filopodia formation in cells.

Conclusion

Curcumin is likely to suppress the fascin expression in GBM cells, and this might be a possible mechanism for anti-migration and anti-invasion effects of Curcumin via inhibition of STAT3 phosphorylation.

Robo1 and vimentin regulate radiation-induced motility of human glioblastoma cells

Glioblastoma is a primary brain tumor with a poor prognosis despite of many treatment regimens. Radiotherapy significantly prolongs patient survival and remains the most common treatment. Slit2 and Robo1 are evolutionarily conserved proteins involved in axon guidance, migration, and branching of neuronal cells. New studies have shown that Slit2 and Robo1 could play important roles in leukocyte chemotaxis and glioblastoma cell migration. Therefore, we investigated whether the Slit2/Robo1 complex has an impact on the motility of glioblastoma cells and whether irradiation with therapeutic doses modulates this effect. Our results indicate that photon irradiation increases the migration of glioblastoma cells in vitro. qPCR and immunoblotting experiments in two different glioblastoma cell lines (U-373 MG and U-87 MG) with different malignancy revealed that both Slit2 and Robo1 are significantly lower expressed in the cell populations with the highest motility and that the expression was reduced after irradiation. Overexpression of Robo1 significantly decreased the motility of glioblastoma cells and inhibited the accelerated migration of wild-type cells after irradiation. Immunoblotting analysis of migration-associated proteins (fascin and focal adhesion kinase) and of the epithelial-mesenchymal-transition-related protein vimentin showed that irradiation affected the migration of glioblastoma cells by increasing vimentin expression, which can be reversed by the overexpression of Slit2 and Robo1. Our findings suggest that Robo1 expression might counteract migration and also radiation-induced migration of glioblastoma cells, a process that might be connected to mesenchymal-epithelial transition.

Modulation of the inwardly rectifying potassium channel Kir4.1 by the pro-invasive miR-5096 in glioblastoma cells

Inwardly rectifying potassium channels (Kir), and especially the barium-sensitive Kir4.1 encoded by KCNJ10, are key regulators of glial functions. A lower expression or mislocation of Kir4.1 is detected in human brain tumors. MicroRNAs participate in the regulation of ionic channels and associated neurologic disorders. Here, we analyze effects of miR-5096 on the Kir4.1 expression and function in two glioblastoma cell lines, U87 and U251. Using whole-cell patch-clamp and western-blot analysis, we show that cell loading with miR-5096 decreases the Kir4.1 protein level and associated K⁺ current. Cell treatment with barium, a Kir4.1 blocker, or cell loading of miR-5096 both increase the outgrowth of filopodia in glioma cells, as observed by time-lapse microscopy. Knocking-down Kir4.1 expression by siRNA transfection similarly increased both filopodia formation and invasiveness of glioma cells as observed in Boyden chamber assay. MiR-5096 also promotes the release of extracellular vesicles by which it increases its own transfer to surrounding cells, in a Kir4.1-dependent manner in U251 but not in U87. Altogether, our results validate Kir4.1 as a miR-5096 target to promote invasion of glioblastoma cells. Our data highlight the complexity of microRNA effects and the role of K⁺ channels in cancer.

Fascin2 regulates cisplatin-induced apoptosis in NRK-52E cells

Previous studies have shown that the aging kidney has a marked loss of α(E)-catenin in proximal tubular epithelium. α-Catenin, a key regulator of the actin cytoskeleton, interacts with a variety of actin-binding proteins. Cisplatin-induced loss of fascin2, an actin bundling protein, was observed in cells with a stable knockdown of α(E)-catenin (C2 cells), as well as in aging (24 mon), but not young (4 mon), kidney. Fascin2 co-localized with α-catenin and the actin cytoskeleton in NRK-52E cells. Knockdown of fascin2 increased the susceptibility of tubular epithelial cells to cisplatin-induced injury. Overexpression of fascin2 in C2 cells restored actin stress fibers and attenuated the increased sensitivity of C2 cells to cisplatin-induced apoptosis. Interestingly, fascin2 overexpression attenuated cisplatin-induced mitochondrial dysfunction and oxidative stress in C2 cells. These data demonstrate that fascin2, a putative target of α(E)-catenin, may play important role in preventing cisplatin-induced acute kidney injury.

Deregulation of focal adhesion formation and cytoskeletal tension due to loss of A-type lamins

The nuclear lamina mechanically integrates the nucleus with the cytoskeleton and extracellular environment and regulates gene expression. These functions are exerted through direct and indirect interactions with the lamina's major constituent proteins, the A-type lamins, which are encoded by the LMNA gene. Using quantitative stable isotope labeling-based shotgun proteomics we have analyzed the proteome of human dermal fibroblasts in which we have depleted A-type lamins by means of a sustained siRNA-mediated LMNA knockdown. Gene ontology analysis revealed that the largest fraction of differentially produced proteins was involved in actin cytoskeleton organization, in particular proteins involved in focal adhesion dynamics, such as actin-related protein 2 and 3 (ACTR2/3), subunits of the ARP2/3 complex, and fascin actin-bundling protein 1 (FSCN1). Functional validation using quantitative immunofluorescence showed a significant reduction in the size of focal adhesion points in A-type lamin depleted cells, which correlated with a reduction in early cell adhesion capacity and an increased cell motility. At the same time, loss of A-type lamins led to more pronounced stress fibers and higher traction forces. This phenotype could not be mimicked or reversed by experimental modulation of the STAT3-IL6 pathway, but it was partly recapitulated by chemical inhibition of the ARP2/3 complex. Thus, our data suggest that the loss of A-type lamins perturbs the balance between focal adhesions and cytoskeletal tension. This imbalance may contribute to mechanosensing defects observed in certain laminopathies.

MicroRNA-133b inhibits the migration and invasion of non small cell lung cancer cells via targeting FSCN1

MicroRNA (miR)-133b has been reported to act as a tumor suppressor in multiple types of human cancers, including non small cell lung cancer (NSCLC). However, the underlying mechanism by which miR-133b inhibits NSCLC metastasis remains largely unclear. In the present study, reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect messenger RNA and protein expression. A wound healing assay and transwell assay were used to examine the cell migration and invasion. The expression level of miR-133b was found to be significantly downregulated in NSCLC cell lines compared with normal lung epithelial BEAS-2B cells. Further investigation identified fascin1 (FSCN1) as a direct target of miR-133b in NSCLC cells. The expression of FSCN1 was significantly increased in NSCLC cell lines compared with BEAS-2B cells, and its protein expression was negatively regulated by miR-133b in NSCLC A549 cells. Further investigation showed that the upregulation of miR-133b notably inhibited NSCLC cell migration and invasion, while the overexpression of FSCN1 significantly promoted NSCLC cell migration and invasion. Furthermore, the overexpression of FSCN1 reversed the suppressive effect of miR-133b overexpression on NSCLC cell migration and invasion. Accordingly, the present study suggests that miR-133b inhibits the migration and invasion of NSCLC cells via directly targeting FSCN1, and thus may be used for the treatment of NSCLC metastasis.

Temozolomide induces the expression of the glioma Big Potassium (gBK) ion channel, while inhibiting fascin-1 expression: possible targets for glioma therapy

OBJECTIVE

Temozolomide (TMZ) improves Glioblastoma Multiforme (GBM) patient survival. The invasive behavior of the glioma cells is the cause of GBM relapse. The glioma BK ion channel (gBK) may provide glioma cells with a mechanism to invade surrounding tissue. gBK contains epitopes that cytolytic T lymphocytes (CTLs) can recognize and kill glioma cells. Fascin-1 is an actin crosslinking molecule that supports microvilli; these membrane protrusions provide a physical defense against CTLs. TMZ was investigated to determine its effect on gBK and fascin-1 expression.

RESEARCH DESIGN AND METHODS

Human glioma cells cultured in TMZ were analyzed for their altered mRNA and gBK protein levels by using quantitative real time PCR, immunostaining and cellular functional assays.

RESULTS

TMZ slowed glioma cell growth and inhibited their transmigratory properties due to loss of fascin-1. TMZ induced increased gBK and HLA expression and allowed these TMZ-treated cells to become better targets for gBK-specific CTLs.

CONCLUSIONS

Besides its traditional chemotherapeutic effect, TMZ can have four other targeted pathways: 1) slowed glioma cell growth; 2) inhibited glioma cell transmigration; 3) increased HLA-A2 and gBK tumor antigen production; 4) increased CTL-mediated cytolysis of the TMZ treated glioma cells due to the loss of their defensive membrane protrusions supported by fascin-1.

The clinical significance of fascin expression in a newly diagnosed primary glioblastoma

The actin-binding protein fascin has been associated with clinically aggressive tumors and poor prognosis. The purpose of this study was to investigate possibility of fascin expression as a prognostic factor in a newly diagnosed primary glioblastoma (GBM). Between July 2007 and December 2013, 37 out of 126 patients diagnosed with GBM satisfied the following inclusion criteria: (1) the presence of immunohistochemically-available tissue, (2) a new primary GBM, (3) gross-total resection, and (4) standardized adjuvant treatment, known as the Stupp regimen. The median follow-up period was 18 months (range 5-95). According to the staining intensity of fascin, progression-free survival (PFS) in the low-intensity fascin group (median PFS 9.0 months; 95 % CI 6.0-12.0) was longer than PFS in the high-intensity fascin group (median PFS 7.0 months; 95 % CI 5.6-10.4; p = 0.024). Overall survival (OS) in the low-intensity fascin group (median OS 20.0 months; 95 % CI 17.7-22.4) was longer than OS in the high-intensity fascin group (median OS 13.0 months; 95 % CI 8.2-17.8; p = 0.031). And, the staining intensity of fascin was a statistically significant factor in PFS and OS according to univariate and multivariate analyses (univariate analysis p = 0.043 and p = 0.043; multivariate analysis p = 0.041 and p = 0.044). Our clinical study showed that fascin expression intensity may be correlated with clinical outcomes of a newly diagnosed primary GBM, especially with regard to PFS and OS.

miR-200b inhibits migration and invasion in non-small cell lung cancer cells via targeting FSCN1

Distant metastasis of non-small cell lung cancer (NSCLC) leads to high postoperative recurrence and low long‑term survival rates. Deregulation of microRNA (miR)-200b has been demonstrated to be associated with NSCLC metastasis. However, the underlying molecular mechanism of miR‑200b in mediating NSCLC cell migration and invasion remains to be fully elucidated. In the current study, reverse transcription‑quantitative polymerase chain reaction data indicated that miR‑200b was significantly downregulated in several NSCLC cell lines, including A549, L78, H1229, H358 and H1650, compared with a normal human lung epithelial cell line, BEAS‑2B. Overexpression of miR‑200b significantly inhibited NSCLC cell migration and invasion. Bioinformatics analysis and a luciferase reporter assay were additionally conducted, which identified fascin actin‑bundling protein 1 (FSCN1) as a novel target of miR‑200b. In addition, miR‑200b negatively mediated the protein expression of FSCN1 in NSCLC H1229 cells. siRNA‑mediated FSCN1 inhibition also significantly inhibited the migration and invasion of H1229 cells. In addition, overexpression of FSCN1 effectively reversed the suppressive effect of miR‑200b overexpression on NSCLC cell migration and invasion. Accordingly, it is suggested that miR‑200b is able to inhibit the migration and invasion of NSCLC cells, partly at least, via targeting FSCN1. The current study provides novel insight into miR‑200 regulation in NSCLC metastasis.

Mechanical confinement triggers glioma linear migration dependent on formin FHOD3

Glioblastomas are extremely aggressive brain tumors with highly invasive properties. Brain linear tracks such as blood vessel walls constitute their main invasive routes. Here we analyze rat C6 and patient-derived glioma cell motility in vitro using micropatterned linear tracks to mimic blood vessels. On laminin-coated tracks (3-10 μm), these cells used an efficient saltatory mode of migration similar to their in vivo migration. This saltatory migration was also observed on larger tracks (50-400 μm in width) at high cell densities. In these cases, the mechanical constraints imposed by neighboring cells triggered this efficient mode of migration, resulting in the formation of remarkable antiparallel streams of cells along the tracks. This motility involved microtubule-dependent polarization, contractile actin bundles and dynamic paxillin-containing adhesions in the leading process and in the tail. Glioma linear migration was dramatically reduced by inhibiting formins but, surprisingly, accelerated by inhibiting Arp2/3. Protein expression and phenotypic analysis indicated that the formin FHOD3 played a role in this motility but not mDia1 or mDia2. We propose that glioma migration under confinement on laminin relies on formins, including FHOD3, but not Arp2/3 and that the low level of adhesion allows rapid antiparallel migration.

The role of FSCN1 in migration and invasion of pituitary adenomas

The prediction of invasion or malignant behavior in PAs remains challenging. FSCN1, an actin-bundling protein, is associated with increased risk of mortality and metastasis in various cancer types. The objective of the study was to evaluate the expression of FSCN1 in 312 PAs cases, and to analyze its association with clinicopathologic features and invasion of PAs, thus serving as a promoter of cancer invasion. In non-function PAs (NFPA), FSCN1 nuclear-positive cases were 53/97 in the invasive group (IPA), and 21/115 in the noninvasive group (nIPA) (ⅹ(2) = 30.65, p = 0.004). FSCN1 cytoplasm-positive cases were 36/97 in IPA, and 8/107 in nIPA (ⅹ(2) = 29.09, p = 0.000). In growth hormone adenomas (GHomas), FSCN1 nuclear-positive were 10/13 in IPA, and 3/37 in nIPA (ⅹ(2) = 23.67, p = 0.000). FSCN1 cytoplasm-positive were 8/13 in IPA, and 2/37 in nIPA (Table 3 ⅹ(2) = 18.94, p = 0.000). Overall, a significant difference was found between FSCN1 expression and tumor size (ⅹ(2) = 46.21, p = 0.000), not age (ⅹ(2) = 2.09, p = 0.148). In the high FSCN1 expression group, 27/137 cases (19.7%) had tumor recurrence, and 10/175 cases (5.7%) in low FSCN1 level (ⅹ(2) = 14.40 p = 0.000). Reduction of FSCN1 suppressed the invasion level of GH3 cells through transwells test. In addition, reduction of FSCN1 can obviously down-regulate the level of Notch1 and DLL3. Our data may help in deciding whether FSCN1 can be a predictor for invasion and recurrence of PAs.

The retinoic acid-metabolizing enzyme CYP26A1 upregulates fascin and promotes the malignant behavior of breast carcinoma cells

The retinoic acid (RA)-metabolizing enzyme CYP26A1 has been shown to efficiently enhance the oncogenic potential of breast cancer, suggesting a potential oncogenic function. We previously demonstrated that CYP26A1 confers unique cell survival properties by modulating the expression of a variety of genes and identified a number of genes that drive the cells into the oncogenic state. Accumulating evidence suggested that fascin is overexpressed in various types of cancer, primarily leading to increased cell motility. Therefore, in the present study, we examined fascin, an actin-bundling protein, using immunohistochemical and SA-β-gal staining as well as TUNEL and colony forming assays. The results of the present study showed that the expression levels of fascin increased significantly in response to CYP26A1 overexpression and, conversely, treatment with all-trans RA downregulated the expression of fascin. In addition, primary breast carcinoma samples, particularly hormone receptor-negative carcinomas and CYP26A1-overexpressing cancers, expressed elevated levels of fascin. Notably, fascin contributed to the ability of breast carcinoma cells to escape premature senescence and exhibit enhanced cell apoptotic resistance, promoting anchorage-independent growth properties. Fascin also promoted cell motility and the invasiveness of CYP26A1-expressing breast carcinoma cells. These data suggest that fascin expression is modulated by the intracellular RA status regulated by the expression of CYP26A1 and plays a significant role in the malignant behavior of CYP26A1-expressing breast carcinoma cells. CYP26A1 exerts oncogenic functions during breast carcinogenesis. Therefore, CYP26A1-mediated oncogenic characteristics may be partially responsible for the elevated expression of fascin.

LS. Dynamics of Circulating γδ T Cell Activity in an Immunocompetent Mouse Model of High-Grade Glioma

Human γδ T cells are potent effectors against glioma cell lines in vitro and in human/mouse xenograft models of glioblastoma, however, this effect has not been investigated in an immunocompetent mouse model. In this report, we established GL261 intracranial gliomas in syngeneic WT C57BL/6 mice and measured circulating γδ T cell count, phenotype, Vγ/Vδ repertoire, tumor histopathology, NKG2D ligands expression, and T cell invasion at day 10-12 post-injection and at end stage. Circulating γδ T cells transiently increased and upregulated Annexin V expression at post-tumor day 10-12 followed by a dramatic decline in γδ T cell count at end stage. T cell receptor repertoire showed no changes in Vγ1, Vγ4, Vγ7 or Vδ1 subsets from controls at post-tumor day 10-12 or at end stage except for an end-stage increase in the Vδ4 population. Approximately 12% of γδ T cells produced IFN-γ. IL-17 and IL-4 producing γδ T cells were not detected. Tumor progression was the same in TCRδ-/- C57BL/6 mice as that observed in WT mice, suggesting that γδ T cells exerted neither a regulatory nor a sustainable cytotoxic effect on the tumor. WT mice that received an intracranial injection of γδ T cells 15m following tumor placement showed evidence of local tumor growth inhibition but this was insufficient to confer a survival advantage over untreated controls. Taken together, our findings suggest that an early nonspecific proliferation of γδ T cells followed by their depletion occurs in mice implanted with syngeneic GL261 gliomas. The mechanism by which γδ T cell expansion occurs remains a subject for further investigation of the mechanisms responsible for this immune response in the setting of high-grade glioma.

Fascin Overexpression Promotes Cholangiocarcinoma RBE Cell Proliferation, Migration, and Invasion

Fascin is overexpressed in various tumor tissues and is closely related to tumor metastasis and invasion. However, the role of fascin in cholangiocarcinoma RBE cells has not been clearly reported. This study aimed to establish a cholangiocarcinoma cell line with stable and high expression of fascin to observe the effect of fascin on cell proliferation, migration, and invasion. A fascin overexpression vector, pcDNA3.1-Fascin, was constructed and transfected into the human cholangiocarcinoma RBE cell line. The results of real-time polymerase chain reaction, Western blot, and immunofluorescence indicated that fascin was steadily and highly expressed in RBE cells. The results of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and colony formation assay indicated that upregulated fascin expression could enhance cholangiocarcinoma cell proliferation. The results of wound healing assay and transwell assay indicated that fascin could promote cholangiocarcinoma cell migration and invasion, and a further study found that the nuclear factor-κB signaling pathway was activated after upregulation of fascin, whereas E-cadherin expression in these cells was significantly decreased. Additionally, E-cadherin expression was significantly increased after inhibiting nuclear factor-κB activity using inhibitor or small interfering RNA, and E-cadherin expression was decreased by fascin overexpression after nuclear factor-κB inhibition, suggesting that nuclear factor-κB signaling pathway was not involved in the regulation of E-cadherin by fascin. In summary, the results of this study demonstrated that fascin effectively promoted cholangiocarcinoma RBE cell proliferation, migration, and invasion. This study provides evidence for fascin as a potential target in the treatment of cholangiocarcinoma.

Fascin-1 knock-down of human glioma cells reduces their microvilli/filopodia while improving their susceptibility to lymphocyte-mediated cytotoxicity

Cancer cells derived from Glioblastoma multiforme possess membranous protrusions allowing these cells to infiltrate surrounding tissue, while resisting lymphocyte cytotoxicity. Microvilli and filopodia are supported by actin filaments cross-linked by fascin. Fascin-1 was genetically silenced within human U251 glioma cells; these knock-down glioma cells lost their microvilli/filopodia. The doubling time of these fascin-1 knock-down cells was doubled that of shRNA control U251 cells. Fascin-1 knock-down cells lost their transmigratory ability responding to interleukin-6 or insulin-like growth factor-1. Fascin-1 silenced U251 cells were more easily killed by cytolytic lymphocytes. Fascin-1 knock-down provides unique opportunities to augment glioma immunotherapy by simultaneously targeting several key glioma functions: like cell transmigration, cell division and resisting immune responses.

Radial mobility and cytotoxic function of retroviral replicating vector transduced, non-adherent alloresponsive T lymphocytes

We report a novel adaptation of the Radial Monolayer Cell Migration assay, first reported to measure the radial migration of adherent tumor cells on extracellular matrix proteins, for measuring the motility of fluorescently-labeled, non-adherent human or murine effector immune cells. This technique employs a stainless steel manifold and 10-well Teflon slide to focally deposit non-adherent T cells into wells prepared with either confluent tumor cell monolayers or extracellular matrix proteins. Light and/or multi-channel fluorescence microscopy is used to track the movement and behavior of the effector cells over time. Fluorescent dyes and/or viral vectors that code for fluorescent transgenes are used to differentially label the cell types for imaging. This method is distinct from similar-type in vitro assays that track horizontal or vertical migration/invasion utilizing slide chambers, agar or transwell plates. The assay allows detailed imaging data to be collected with different cell types distinguished by specific fluorescent markers; even specific subpopulations of cells (i.e., transduced/nontransduced) can be monitored. Surface intensity fluorescence plots are generated using specific fluorescence channels that correspond to the migrating cell type. This allows for better visualization of the non-adherent immune cell mobility at specific times. It is possible to gather evidence of other effector cell functions, such as cytotoxicity or transfer of viral vectors from effector to target cells, as well. Thus, the method allows researchers to microscopically document cell-to-cell interactions of differentially-labeled, non-adherent with adherent cells of various types. Such information may be especially relevant in the assessment of biologically-manipulated or activated immune cell types, where visual proof of functionality is desired with tumor target cells before their use for cancer therapy.

In vivo evidence for mTORC2-mediated actin cytoskeleton rearrangement in neurons

The mammalian target of rapamycin (mTOR) assembles into two distinct multi-protein complexes called mTORC1 and mTORC2. While mTORC1 controls the signaling pathways important for cell growth, the physiological function of mTORC2 is only partially known. Here we comment on recent work on gene-targeted mice lacking mTORC2 in the cerebellum or the hippocampus that provided strong evidence that mTORC2 plays an important role in neuron morphology and synapse function. We discuss that this phenotype might be based on the perturbed regulation of the actin cytoskeleton and the lack of activation of several PKC isoforms. The fact that PKC isoforms and their targets have been implicated in neurological disease including spinocerebellar ataxia and that they have been shown to affect learning and memory, suggests that aberration of mTORC2 signaling might be involved in diseases of the brain.

Modification and biological evaluation of thiazole derivatives as novel inhibitors of metastatic cancer cell migration and invasion

Fascin has recently emerged as a potential therapeutic target, as its expression in cancer cells is closely associated with tumor progression and metastasis. Following the initial discovery of a series of thiazole derivatives that demonstrated potent antimigration and antiinvasion activities via possible inhibition of fascin function, we report here the design and synthesis of 63 new thiazole derivatives by further structural modifications in search of more potent fascin inhibitors. The 5 series of analogues with longer alkyl chain substitutions on the thiazole nitrogen exhibited greater antimigration activities than those with other structural motifs. The most potent analogue, 5p, inhibited 50% of cell migration at 24 nM. Moreover, the thiazole analogues showed strong antiangiogenesis activity, blocking new blood vessel formation in a chicken embryo membrane assay. Finally, a functional study was conducted to investigate the mechanism of action via interaction with the F-actin bundling protein fascin.

3-Hydroxy-3',4'-dimethoxyflavone suppresses Bcl-w-induced invasive potentials and stemness in glioblastoma multiforme

3-Hydroxy-3',4'-dimethoxyflavone (HDMF) is a natural chemical product that is not currently regarded as a drug. In our study, we employed glioblastoma cells and cell biology and biochemistry approaches to investigate the potential of HDMF as a natural anticancer therapy option. FACS analysis showed that treatment concentration of HDMF does not exert cytotoxicity on U251 cells. Wound-healing and invasion assays showed that HDMF dose-dependently decreased the migratory and invasive potentials of these cells, likely by indirectly inhibiting MMP-3 activity as a result of the inhibition of p38 and ERK signaling proteins - an effect of HDMF also shown by Western blotting. HDMF inhibits Bcl-w-induced neurosphere formation and the expression of glioma stem cell markers, such as Musashi, Sox-2 and c-myc. These results indicate that HDMF suppresses migratory or invasive potentials and stemness and functions as a negative agent against the aggressiveness of glioblastoma cells. We propose that HDMF has potential as anticancer drug for inhibiting the aggressiveness of glioblastoma multiforme (GBM).

AJAP1 is dysregulated at an early stage of gliomagenesis and suppresses invasion through cytoskeleton reorganization

AIMS

Down-regulation of AJAP1 in glioblastoma multiforme (GBM) has been reported. However, the expression profiles of AJAP1 in gliomas and the underlying mechanisms of AJAP1 function on invasion are still poorly understood.

METHODS

The gene profiles of AJAP1 in glioma patients were studied among four independent cohorts. Confocal imaging was used to analyze the AJAP1 localization. After AJAP1 overexpression in GBM cell lines, cellular polarity, cytoskeleton distribution, and antitumor effect were investigated in vitro and in vivo.

RESULTS

AJAP1 expression was significantly decreased in gliomas compared with normal brain in REMBRANDT and CGCA cohorts. Additionally, low AJAP1 expression was associated with worse survival in GBMs in REMBRANDT and TCGA U133A cohorts and was significantly associated with classical and mesenchymal subtypes of GBMs among four cohorts. Confocal imaging indicated AJAP1 localized in cell membranes in low-grade gliomas and AJAP1-overexpressing GBM cells, but difficult to assess in high-grade gliomas due to its absence. AJAP1 overexpression altered the cytoskeleton and cellular polarity in vitro and inhibited the tumor growth in vivo.

CONCLUSIONS

AJAP1 is dysregulated at an early stage of gliomagenesis and may suppress glioma cell invasion and proliferation, which suggests that AJAP1 may be a potential diagnostic and prognostic marker for gliomas.

Stratifying fascin and cortactin function in invadopodium formation using inhibitory nanobodies and targeted subcellular delocalization

Invadopodia are actin-rich protrusions arising through the orchestrated regulation of precursor assembly, stabilization, and maturation, endowing cancer cells with invasive properties. Using nanobodies (antigen-binding domains of Camelid heavy-chain antibodies) as perturbators of intracellular functions and/or protein domains at the level of the endogenous protein, we examined the specific contribution of fascin and cortactin during invadopodium formation in MDA-MB-231 breast and PC-3 prostate cancer cells. A nanobody (K(d)~35 nM, 1:1 stoichiometry) that disrupts fascin F-actin bundling emphasizes the importance of stable actin bundles in invadopodium array organization and turnover, matrix degradation, and cancer cell invasion. Cortactin-SH3 dependent WIP recruitment toward the plasma membrane was specifically inhibited by a cortactin nanobody (K(d)~75 nM, 1:1 stoichiometry). This functional domain is shown to be important for formation of properly organized invadopodia, MMP-9 secretion, matrix degradation, and cancer cell invasion. Notably, using a subcellular delocalization strategy to trigger protein loss of function, we uncovered a fascin-bundling-independent role in MMP-9 secretion. Hence, we demonstrate that nanobodies enable high resolution protein function mapping in cells.

Systematic review of protein biomarkers of invasive behavior in glioblastoma

Glioblastoma (GBM) is an aggressive and incurable brain tumor with a grave prognosis. Recurrence is inevitable even with maximal surgical resection, in large part because GBM is a highly invasive tumor. Invasiveness also contributes to the failure of multiple cornerstones of GBM therapy, including radiotherapy, temozolomide chemotherapy, and vascular endothelial growth factor blockade. In recent years there has been significant progress in the identification of protein biomarkers of invasive phenotype in GBM. In this article, we comprehensively review the literature and survey a broad spectrum of biomarkers, including proteolytic enzymes, extracellular matrix proteins, cell adhesion molecules, neurodevelopmental factors, cell signaling and transcription factors, angiogenic effectors, metabolic proteins, membrane channels, and cytokines and chemokines. In light of the marked variation seen in outcomes in GBM patients, the systematic use of these biomarkers could be used to form a framework for better prediction, prognostication, and treatment selection, as well as the identification of molecular targets for further laboratory investigation and development of nascent, directed therapies.

Candidate biomarker discovery for angiogenesis by automatic integration of Orbitrap MS1 spectral- and X!Tandem MS2 sequencing information

Candidate protein biomarker discovery by full automatic integration of Orbitrap full MS1 spectral peptide profiling and X!Tandem MS2 peptide sequencing is investigated by analyzing mass spectra from brain tumor samples using Peptrix. Potential protein candidate biomarkers found for angiogenesis are compared with those previously reported in the literature and obtained from previous Fourier transform ion cyclotron resonance (FT-ICR) peptide profiling. Lower mass accuracy of peptide masses measured by Orbitrap compared to those measured by FT-ICR is compensated by the larger number of detected masses separated by liquid chromatography (LC), which can be directly linked to protein identifications. The number of peptide sequences divided by the number of unique sequences is 9248/6911 ≈ 1.3. Peptide sequences appear 1.3 times redundant per up-regulated protein on average in the peptide profile matrix, and do not seem always up-regulated due to tailing in LC retention time (40%), modifications (40%) and mass determination errors (20%). Significantly up-regulated proteins found by integration of X!Tandem are described in the literature as tumor markers and some are linked to angiogenesis. New potential biomarkers are found, but need to be validated independently. Eventually more proteins could be found by actively involving MS2 sequence information in the creation of the MS1 peptide profile matrix.

Overexpression of CD99 Increases the Migration and Invasiveness of Human Malignant Glioma Cells

The malignant glioma is the most common primary human brain tumor, and its migration and invasiveness away from the primary tumor mass are considered a leading cause of tumor recurrence and treatment failure. Recently, gene expression profiling revealed that the transmembrane glycoprotein CD99 is more highly expressed in malignant glioma than in normal brain. Although its function is not completely understood, CD99 is implicated in cell adhesion and migration in a variety of different cell types. CD99 has wild-type and splice variant isoforms. Previous studies have shown that wild-type CD99 may be an oncosuppressor in some tumors, distinct from the role of the splice variant isoform. In this study, our data reveal that only wild-type CD99 is expressed in human glioma cells and tissues. Using a tissue microarray, we validated that gliomas demonstrate higher expression of CD99 compared with nonneoplastic brain. To assess the role of CD99 in glioma migration and invasion, we inhibited CD99 expression by siRNA and demonstrated decreased glioma migration and invasion. In contrast, when CD99 was overexpressed in glioma cells, we observed enhancement of cell migration and invasiveness. An orthotopic brain tumor model demonstrates that CD99 overexpression significantly increases invasiveness and decreases survival rate. Interestingly, Rac activity was decreased and Rho activity was increased in CD99 overexpressing glioma cells, and the proportion of amoeboid cells to mesenchymal cells was significantly increased. Taken together, our findings suggest that CD99 may play an important role in the migration and invasion of human gliomas independent of Akt, ERK, or JNK signaling pathways. Moreover, CD99 might be involved in amoeboid-mesenchymal transition in glioma migration. CD99 may be an important future target to inhibit migration and invasion, especially in CD99-expressing gliomas.

The role of fascin in migration and invasion of urothelial carcinoma of the bladder

INTRODUCTION

To investigate the roles of fascin in migration and invasiveness in bladder urothelial carcinoma.

MATERIALS AND METHODS

Immunohistochemical detection of fascin in urothelial carcinoma samples and inhibition the expression of fascin in the urothelial carcinoma cell line were performed, then the differences in cell behaviors before and after silencing of the fascin gene were tested.

RESULTS

In our study, we found that overexpression of fascin was more frequent in urothelial carcinoma tissues (p < 0.001). Fascin expression was positively correlated with histological grade (p = 0.024) and pT stage (p < 0.001). After transfection of fascin shRNA, the expressions of fascin in 5637 cells and BIU87 cells were efficiently decreased according to real-time RT-PCR and Western blot analysis. When fascin was inhibited, a significant decrease in migration and invasion, and increase in adhesion were observed in 5637 cells and BIU87 cells. However, there was no significant change in the proliferation of 5637 cells or BIU87 cells with or without inhibition of the fascin gene.

CONCLUSIONS

Fascin expression can be used as a predictor for transformation and progression of urothelial carcinoma, and reduction of fascin levels may represent a novel therapeutic strategy for urothelial carcinoma of the bladder.

The role of drebrin in glioma migration and invasion

Glioblastoma (GBM) is the most common primary brain tumor in adults. Despite current advances in therapy consisting of surgery followed by chemotherapy and radiation, the overall survival rate still remains poor. Therapeutic failures are partly attributable to the highly infiltrative nature of tumor adjacent to normal brain parenchyma. Recently, evidence is mounting to suggest that actin cytoskeleton dynamics are critical components of the cell invasion process. Drebrin is an actin-binding protein involved in the regulation of actin filament organization, and plays a significant role in cell motility; however, the role of drebrin in glioma cell invasiveness has not yet been fully elucidated. Therefore, this study was aimed to clarify the role of drebrin in glioma cell morphology and cell motility. Here we show that drebrin is expressed in glioma cell lines and in operative specimens of GBM. We demonstrate that stable overexpression of drebrin in U87 cells leads to alterations in cell morphology, and induces increased invasiveness in vitro while knockdown of drebrin in U87 cells by small interfering RNA (siRNA) decreases invasion and migration. In addition, we show that depletion of drebrin by siRNA alters glioma cell morphology in A172 GBM cell line. Our results suggest that drebrin contributes to the maintenance of cell shape, and may play an important role in glioma cell motility.

Differential effects of low- and high-dose GW2974, a dual epidermal growth factor receptor and HER2 kinase inhibitor, on glioblastoma multiforme invasion

Aberrant expression of epidermal growth factor receptor (EGFR; ErbB1) and HER2 (ErbB2) tyrosine kinases frequently occurs in glioblastoma multiforme (GBM) patients and is considered to be associated with tumor malignancy and poor patient prognosis. In the present study, a dual EGFR and HER2 inhibitor (GW2974) was evaluated for its effects in GBM in vitro and in vivo. Results showed that low-concentration GW2974 inhibited GBM cell invasion, whereas a high concentration of the same compound counteracted this effect. Similar results were observed in an intracranial GBM xenograft model, in which, although both doses of GW2974 slowed tumor growth, no improvement in survival was observed in mice treated with high-dose GW2974, presumably because of the augmentation of tumor invasion. By protein microarray and Western blot analyses, the p38 mitogen-activated protein kinase (MAPK) pathway was found to be activated in GBM cells under high-concentration GW2974. Additionally, blockage of the p38 MAPK pathway reproduced the inhibitory effect of low-concentration GW2974 on cell invasion. These data suggest that the p38 MAPK pathway might contribute to the differential regulation of cell invasion by GW2974. Taken together, our results indicate that GW2974 exerts different effects in GBM depending on drug dosage. This offers a new perspective on the role of GW2974 in tumor progression, providing a potential strategy for GBM treatment based on precise prescription.

Drosophila Fascin is a novel downstream target of prostaglandin signaling during actin remodeling

Prostaglandins (PGs) regulate the actin cytoskeleton. However, their mechanisms of action are unknown. Use of Drosophila oogenesis—specifically nurse cell dumping—as a model shows that PGs regulate the actin bundler Fascin to control parallel actin filament bundle formation and cortical actin integrity.

Although prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin cytoskeletal dynamics, their mechanisms of action are unknown. We previously established Drosophila oogenesis, in particular nurse cell dumping, as a new model to determine how PGs regulate actin remodeling. PGs, and thus the Drosophila COX-like enzyme Pxt, are required for both the parallel actin filament bundle formation and the cortical actin strengthening required for dumping. Here we provide the first link between Fascin (Drosophila Singed, Sn), an actin-bundling protein, and PGs. Loss of either pxt or fascin results in similar actin defects. Fascin interacts, both pharmacologically and genetically, with PGs, as reduced Fascin levels enhance the effects of COX inhibition and synergize with reduced Pxt levels to cause both parallel bundle and cortical actin defects. Conversely, overexpression of Fascin in the germline suppresses the effects of COX inhibition and genetic loss of Pxt. These data lead to the conclusion that PGs regulate Fascin to control actin remodeling. This novel interaction has implications beyond Drosophila, as both PGs and Fascin-1, in mammalian systems, contribute to cancer cell migration and invasion.

A cell-based fascin bioassay identifies compounds with potential anti-metastasis or cognition-enhancing functions

The actin-bundling protein fascin is a key mediator of tumor invasion and metastasis and its activity drives filopodia formation, cell-shape changes and cell migration. Small-molecule inhibitors of fascin block tumor metastasis in animal models. Conversely, fascin deficiency might underlie the pathogenesis of some developmental brain disorders. To identify fascin-pathway modulators we devised a cell-based assay for fascin function and used it in a bidirectional drug screen. The screen utilized cultured fascin-deficient mutant Drosophila neurons, whose neurite arbors manifest the 'filagree' phenotype. Taking a repurposing approach, we screened a library of 1040 known compounds, many of them FDA-approved drugs, for filagree modifiers. Based on scaffold distribution, molecular-fingerprint similarities, and chemical-space distribution, this library has high structural diversity, supporting its utility as a screening tool. We identified 34 fascin-pathway blockers (with potential anti-metastasis activity) and 48 fascin-pathway enhancers (with potential cognitive-enhancer activity). The structural diversity of the active compounds suggests multiple molecular targets. Comparisons of active and inactive compounds provided preliminary structure-activity relationship information. The screen also revealed diverse neurotoxic effects of other drugs, notably the 'beads-on-a-string' defect, which is induced solely by statins. Statin-induced neurotoxicity is enhanced by fascin deficiency. In summary, we provide evidence that primary neuron culture using a genetic model organism can be valuable for early-stage drug discovery and developmental neurotoxicity testing. Furthermore, we propose that, given an appropriate assay for target-pathway function, bidirectional screening for brain-development disorders and invasive cancers represents an efficient, multipurpose strategy for drug discovery.

Migfilin protein promotes migration and invasion in human glioma through epidermal growth factor receptor-mediated phospholipase C-γ and STAT3 protein signaling pathways

Migfilin is critical for cell shape and motile regulation. However, its pathological role in glioma is unknown. Using an immunohistochemical staining assay, we demonstrate that there is a significant correlation between expression of Migfilin and pathological tumor grade in 217 clinical glioma samples. High Migfilin expression is associated with poor prognosis for patients with glioma. Investigation of the molecular mechanism shows that Migfilin promotes migration and invasion in glioma cells. Moreover, Migfilin positively modulates the expression and activity of epidermal growth factor receptor, and Migfilin-mediated migration and invasion depend on epidermal growth factor receptor-induced PLC-γ and STAT3-signaling pathways. Our results may provide significant clinical application, including use of Migfilin as a molecular marker in glioma for early diagnosis and as an indicator of prognosis.

Tunneling nanotubes provide a unique conduit for intercellular transfer of cellular contents in human malignant pleural mesothelioma

Tunneling nanotubes are long, non-adherent F-actin-based cytoplasmic extensions which connect proximal or distant cells and facilitate intercellular transfer. The identification of nanotubes has been limited to cell lines, and their role in cancer remains unclear. We detected tunneling nanotubes in mesothelioma cell lines and primary human mesothelioma cells. Using a low serum, hyperglycemic, acidic growth medium, we stimulated nanotube formation and bidirectional transfer of vesicles, proteins, and mitochondria between cells. Notably, nanotubes developed between malignant cells or between normal mesothelial cells, but not between malignant and normal cells. Immunofluorescent staining revealed their actin-based assembly and structure. Metformin and an mTor inhibitor, Everolimus, effectively suppressed nanotube formation. Confocal microscopy with 3-dimensional reconstructions of sectioned surgical specimens demonstrated for the first time the presence of nanotubes in human mesothelioma and lung adenocarcinoma tumor specimens. We provide the first evidence of tunneling nanotubes in human primary tumors and cancer cells and propose that these structures play an important role in cancer cell pathogenesis and invasion.

An immunohistochemical analysis-based decision tree model for estimating the risk of lymphatic metastasis in pN0 squamous cell carcinomas of the lung

AIMS

Lung cancer patients within the pN0 category have a significantly different outcome. The aim of this study was to develop a mathematical model to assist in predicting the prognosis of pN0 lung squamous cell carcinoma (SCC).

METHODS AND RESULTS

Twenty-three proteins were examined by immunohistochemical (IHC) analysis on primary tumour tissues from 319 lung SCC patients. In a training group, using IHC data, a recursive partitioning decision tree (RP-DT) was used to build a model for estimating the risk for lymphatic metastasis. This model was then validated in a test cohort. Of 23 proteins, 8 (matrix metallopeptidase 1, metalloproteinase inhibitor 1, Ras GTPase-activating-like protein IQGAP1, targeting protein for Xklp2, urokinase-type plasminogen activator, cathepsin D, fascin, polymeric immunoglobulin receptor/secretory component) were selected, and generated a tree model in a training group of 255 patients to classify them as at high or low risk of lymphatic invasion, with accuracy of 78.0% (compared to histopathological diagnosis), sensitivity of 83.0% and specificity of 70.3%. When the tree model was applied to the test group, the accuracy, sensitivity and specificity were 76.6%, 76.0% and 76.9%, respectively. The performance of this mathematical model was substantiated further in 34 'problematic' stage I/pN0 patients by survival analysis.

CONCLUSIONS

The RP-DT model, constructed with eight protein markers for estimating lymphatic metastasis risk in pN0 lung SCC, is clinically feasible and practical, using IHC data from the primary tumour.