Induction of fascin spikes in breast cancer cells by activation of the insulin-like growth factor-I receptor

The crucial role of fascin-1 in the pathogenesis, metastasis, and chemotherapeutic resistance of breast cancer

Breast cancer (BC) is the most common type of cancer in women to be diagnosed, and it is also the second leading cause of cancer death in women globally. It is the disease that causes the most life years adjusted for disability lost among women, making it a serious worldwide health issue. Understanding and interpreting carcinogenesis and metastatic pathways is critical for curing malignancy. Fascin-1 was recognized as an actin-bundling protein with parallel, rigid bundles as a result of the cross-linking of F-actin microfilaments. Increasing levels of fascin-1 have been associated with bad prognostic profiles, aggressiveness of clinical courses, and poor survival outcomes in a variety of human malignancies. Cancer cells that overexpress fascin-1 have higher capabilities for proliferation, invasion, migration, and metastasis. Fascin-1 is being considered as a potential target for therapy as well as a potential biomarker for diagnostics in a variety of cancer types. This review aims to provide an overview of the FSCN1 gene and its protein structure, elucidate its physiological and pathological roles, and throw light on its involvement in the initiation, development, and chemotherapeutic resistance of BC.

Fascin-1: Updated biological functions and therapeutic implications in cancer biology

Filopodia are cellular protrusions that respond to a variety of stimuli. Filopodia are formed when actin is bound to the protein Fascin, which may play a crucial role in cellular interactions and motility during cancer metastasis. Significantly, the noncanonical features of Fascin-1 are gradually being clarified, including the related molecular network contributing to metabolic reprogramming, chemotherapy resistance, stemness ac-tivity, and tumor microenvironment events. However, the relationship between biological characteristics and pathological features to identify effective therapeutic strategies needs to be studied further. The pur-pose of this review article is to provide a broad overview of the latest molecular networks and multiomics research regarding fascins and cancer. It also highlights their direct and indirect effects on available cancer treatments. With this multidisciplinary approach, researchers and clinicians can gain the most relevant in-formation on the function of fascins in cancer progression, which may facilitate clinical applications in the future.

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.

MiR-145 suppresses embryo-epithelial juxtacrine communication at implantation by modulating maternal IGF1R

Successful implantation requires the synchronization of viable embryonic development with endometrial receptivity. The mechanisms allowing for the initiation of crosstalk between the embryo and the endometrium remain elusive; however, recent studies have revealed that there are alterations in endometrial microRNAs (miRs) in women suffering repeated implantation failure and that one of the altered miRs is miR-145. We assessed the role of miR-145 and its target IGF1R, in early implantation. miR-145 overexpression and IGF1R knockdown were achieved in Ishikawa endometrial cells. Quantitative PCR, western blotting and 3'UTR luciferase reporter assays confirmed that IGF1R is a direct target of miR-145 in the endometrium. Attachment of mouse embryos or IGF1-coated beads to endometrial epithelial cells was used to study the effects of altered miR-145 and/or IGF1R expression on early implantation events. miR-145 overexpression or specific reduction of IGF1R impaired attachment in both cases. An IGF1R target protector prevented the miR-145-mediated reduction in IGF1R and reversed the effect of miR-145 overexpression on attachment. The data demonstrate that miR-145 influences embryo attachment by reducing the level of IGF1R in endometrium.

The small GTPase Rap1 promotes cell movement rather than stabilizes adhesion in epithelial cells responding to insulin-like growth factor I

The Ras-related GTPase Rap1 promotes cell adhesion and migration. Although the significance of Rap1 contribution to cell migration is increasingly being recognized, little is known about the biochemical mechanisms driving this process. In the present study, we discovered a previously unidentified regulatory role of insulin-like growth factor type I (IGF-I) receptor (IGF-IR) in CRK Src homology 3 (SH3)-binding guanine-nucleotide-releasing protein (C3G)-Rap1-fascin-actin axis promoting cell movement. We demonstrate that a burst of Rap1 activity, rather than presumed hyperactivation, is imperative for the onset of cell movement. We show that while autophosphorylated IGF-IR signals to C3G to activate Rap1, subsequent IGF-IR internalization promotes gradual inactivation of Rap1 by putative Rap1 GTPase-activating protein (GAP). Additionally, IGF-IR signalling recruits active Rap1 at sites of cell motile protrusions. C3G depletion prevents IGF-I-induced fascin accumulation at actin microspikes and blocks protrusions. In the absence of IGF-IR activity, the wild-type (WT) Rap1 and the constitutively active V12Rap1 mutant remain in cell-cell contacts. Forced inactivation of Rap1 signalling by overexpressing dominant negative N17Rap1, Rap1GAP or by silencing C3G has a detrimental effect on filamentous (F)-actin and cell adhesion irrespective of IGF-IR signalling. We conclude that the basal levels of Rap1 activity holds up cell adhesion, whereas sequential regulation of C3G and GAP by IGF-IR reverses the labile Rap1 function from supporting adhesion to promoting migration.

Strong association of fascin expression with triple negative breast cancer and basal-like phenotype in African-American women

BACKGROUND

Fascin, an actin bundling protein, plays a critical role in cell motility due to formation of actin rich protrusions called filopodia, important in cell migration, invasion and metastatic spread. Fascin overexpression has been associated with epithelial to mesenchymal transition and correlates with progression and unfavourable prognosis in breast carcinoma.

OBJECTIVE

To evaluate fascin expression by immunohistochemistry and correlate the expression pattern with clinicopathological parameters in breast cancer in African-American (AA) women, in whom triple negative breast cancer (TNBC), an aggressive subtype, is more prevalent.

METHODS

Tissue microarrays were constructed from formalin-fixed, paraffin-embedded blocks of tumour tissue from primary breast carcinomas in 202 AA women. Immunohistochemical detection of fascin was correlated with four major subtypes of breast carcinoma (luminal A, luminal B, human epidermal growth factor receptor 2 and triple negative (TN)) and other clinicopathological factors, including age, grade, tumour size, stage, regional lymph node status and survival.

RESULTS

We observed a significant association between fascin expression and TN subtype, oestrogen receptor (ER) negativity, progesterone receptor (PR) negativity, Elston-Nottingham (EN) grade 3 and decreased overall survival. There was also a significant association between expression of CK 5/6, a marker of basal-like phenotype, and fascin expression.

CONCLUSION

These results suggest that fascin is a marker for TN subtype having a basal-like phenotype and decreased overall survival. Fascin may represent a target for therapy in TNBC in AA women.

MicroRNA-451 regulates AMPK/mTORC1 signaling and fascin1 expression in HT-29 colorectal cancer

The earlier studies have shown that Fascin1 (FSCN1), the actin bundling protein, is over-expressed in colorectal cancers, and is associated with cancer cell progression. Here, we aimed to understand the molecular mechanisms regulating FSCN1 expression by focusing on mammalian target of rapamycin (mTOR) signaling and its regulator microRNA-451. We found that microRNA-451 was over-expressed in multiple colorectal cancer tissues, and its expression was correlated with mTOR complex 1 (mTORC1) activity and FSCN1 expression. In cultured colorectal cancer HT-29 cells, knockdown of FSCN1 by RNAi inhibited cell migration and proliferation. Activation of mTORC1 was required for FSCN1 expression, HT-29 cell migration and proliferation, as RAD001 and rapamycin, two mTORC1 inhibitors, suppressed FSCN1 expression, HT-29 cell migration and proliferation. Meanwhile, forced activation of AMP-activated protein kinase (AMPK), the negative regulator of mTORC1, by its activators or by the genetic mutation, inhibited mTORC1 activation, FSCN1 expression, cell migration and proliferation. In HT-29 cells, we found that over-expression of microRNA-451 inhibited AMPK activation, causing mTORC1 over-activation and FSCN1 up-regulation, cells were with high migration ability and proliferation rate. Significantly, these effects by microRNA-451 were largely inhibited by mTORC1 inhibitors or the AMPK activator AICAR. On the other hand, knockdown of miRNA-451 by the treatment of HT-29 cells with miRNA-451 antagomir inhibited mTORC1 activation and FSCN1 expression. The proliferation and migration of HT-29 cells after miRNA-45 knockdown were also inhibited. Our results suggested that the over-expressed microRNA-451 in colon cancer cells might inhibit AMPK to activate mTORC1, which mediates FSCN1 expression and cancer cell progression.

Fascin regulates the migration of subventricular zone-derived neuroblasts in the postnatal brain

After birth, stem cells in the subventricular zone (SVZ) generate neuroblasts that migrate along the rostral migratory stream (RMS) to become interneurons in the olfactory bulb (OB). This migration is a fundamental event controlling the proper integration of new neurons in a pre-existing synaptic network. Many regulators of neuroblast migration have been identified; however, still very little is known about the intracellular molecular mechanisms controlling this process. Here, we show that the actin-bundling protein fascin is highly upregulated in mouse SVZ-derived migratory neuroblasts. Fascin-1ko mice display an abnormal RMS and a smaller OB. Bromodeoxyuridine labeling experiments show that lack of fascin significantly impairs neuroblast migration, but does not appear to affect cell proliferation. Moreover, fascin depletion substantially alters the polarized morphology of rat neuroblasts. Protein kinase C (PKC)-dependent phosphorylation of fascin on Ser39 regulates its actin-bundling activity. In vivo postnatal electroporation of phosphomimetic (S39D) or nonphosphorylatable (S39A) fascin variants followed by time-lapse imaging of brain slices demonstrates that the phospho-dependent modulation of fascin activity ensures efficient neuroblast migration. Finally, fluorescence lifetime imaging microscopy studies in rat neuroblasts reveal that the interaction between fascin and PKC can be modulated by cannabinoid signaling, which controls neuroblast migration in vivo. We conclude that fascin, whose upregulation appears to mark the transition to the migratory neuroblast stage, is a crucial regulator of neuroblast motility. We propose that a tightly regulated phospho/dephospho-fascin cycle modulated by extracellular signals is required for the polarized morphology and migration in neuroblasts, thus contributing to efficient neurogenesis.

IL-6 augmented motility of airway epithelial cell BEAS-2B via Akt/GSK-3β signaling pathway

Cell migration plays a pivotal role in airway repair and remodeling involved in respiratory diseases such as asthma. Interleukin-6 (IL-6) and fascin-1 are involved in cell migration upon stimulation; however, the roles of IL-6 and fascin-1 in migration of airway epithelial cell remain sketchy. The present study was aimed to investigate influence of IL-6 on cell motility with emphasis on the association with fascin-1. Wound healing assay and transmigration assay were performed to examine effect of IL-6 on migration and invasiveness of human bronchial epithelial cell BEAS-2B. Level of mRNA expression was determined by RT-PCR and quantitative real-time RT-PCR (Q-PCR). Involvement of kinase and transcription factor signaling in IL-6-induced cell migration was investigated using immunoblot and specific inhibitors. IL-6 significantly augmented cell migration and invasiveness in parallel with elevated fascin-1 expression. Further investigation showed that IL-6 dose-dependently upregulated fascin-1 expression in both mRNA and protein levels. We showed that IL-6 activated Akt and inhibited glycogen synthase kinase-3β (GSK-3β), highly associating with fascin-1 mRNA expression. Additionally, IL-6-induced migration was significantly diminished by phosphatidyl inositol 3-phosphate kinase (PI3K) inhibitor (wortamannin) and β-catenin inhibitor FH535. Moreover, LiCl and SB216763, inhibitors of GSK-3β augmented cell migration as well as fascin-1 mRNA expression. Conclusively, these findings reveal that IL-6-induced migration of BEAS-2B cell may be attributed to activation of Akt, inhibition of GSK-3β, and the associated increase of β-catenin and fascin-1 expression, indicating an important role of Akt/GSK-3β signaling and β-catenin/fascin-1 in IL-6 associated airway remodeling.

Actin binding proteins: their ups and downs in metastatic life

In order to metastasize away from the primary tumor site and migrate into adjacent tissues, cancer cells will stimulate cellular motility through the regulation of their cytoskeletal structures. Through the coordinated polymerization of actin filaments, these cells will control the geometry of distinct structures, namely lamella, lamellipodia and filopodia, as well as the more recently characterized invadopodia. Because actin binding proteins play fundamental functions in regulating the dynamics of actin polymerization, they have been at the forefront of cancer research. This review focuses on a subset of actin binding proteins involved in the regulation of these cellular structures and protrusions, and presents some general principles summarizing how these proteins may remodel the structure of actin. The main body of this review aims to provide new insights into how the expression of these actin binding proteins is regulated during carcinogenesis and highlights new mechanisms that may be initiated by the metastatic cells to induce aberrant expression of such proteins.

Fascin: a key regulator of cytoskeletal dynamics

Fascin is a 55 kDa actin-bundling protein and is an important regulatory element in the maintenance and stability of parallel bundles of filamentous actin in a variety of cellular contexts. Regulation of fascin function is under the control of a number of different signalling pathways that act in concert to spatially regulate the actin-binding properties of this protein. The ability of fascin to bind and bundle actin plays a central role in the regulation of cell adhesion, migration and invasion. Fascin has received considerable attention recently as an emerging key prognostic marker of metastatic disease. Studies are now underway to better understand the precise regulation of this protein in the context of tumour progression and to investigate fascin as a potential therapeutic target for a number of forms of cancer.

Motile membrane protrusions regulate cell-cell adhesion and migration of olfactory ensheathing glia

Olfactory ensheathing cells (OECs) are candidates for therapeutic approaches for neural regeneration due to their ability to assist axon regrowth in central nervous system lesion models. However, little is understood about the processes and mechanisms underlying migration of these cells. We report here that novel lamellipodial protrusions, termed lamellipodial waves, are integral to OEC migration. Time-lapse imaging of migrating OECs revealed that these highly dynamic waves progress along the shaft of the cells and are crucial for mediating cell-cell adhesion. Without these waves, cell-cell adhesion does not occur and migrational rates decline. The activity of waves is modulated by both glial cell line-derived neurotrophic factor and inhibitors of the JNK and SRC kinases. Furthermore, the activity of lamellipodial waves can be modulated by Mek1, independently of leading edge activity. The ability to selectively regulate cell migration via lamellipodial waves has implications for manipulating the migratory behavior of OECs during neural repair.

Expression of fascin in oral and oropharyngeal squamous cell carcinomas has prognostic significance - a tissue microarray study of 129 cases

AIMS

To elucidate the role of fascin in oral and oropharyngeal squamous cell carcinoma (OSCC) by correlation with clinical parameters.

METHODS AND RESULTS

Paraffin sections using tissue microarrays of 129 patients with OSCC were investigated immunohistochemically. Fascin protein was overexpressed in OSCC cells compared with their non-neoplastic epithelial counterparts. For evaluating the intensity of fascin, 39 (30.2%) were classified as weakly immunoreactive, 76 (58.9%) as moderate reactive and 14 (10.9%) as intensely reactive. For evaluating the distribution of fascin, 64 (49.6%) were classified as < 55% and 65 (50.4%) were classified as >/= 55%. Fascin protein expression was correlated with size or extent of the tumour (P < 0.001), positive lymph node metastasis (P < 0.001), distant metastasis (P = 0.014) and clinical staging (P < 0.001). The immunoreactivity scores of fascin in OSCC were variable but showed significant correlation with histological grade, clinical TNM system and stage.

CONCLUSION

Expression of fascin protein may play an important role in progression of OSCC. Overexpression of fascin contributes to a more aggressive clinical course and suggests the potential of fascin as a new molecular target for therapeutic intervention.

Effects of Body Weight and Nutrition on Mammary Protein Expression Profiles in Holstein Heifers

A proteomics approach was used to characterize biochemical and cellular mechanisms governing effects of peripubertal feeding on heifer mammary development. Mammary parenchymal tissue from 24 Holstein heifers randomly assigned to treatments arranged in a 2 x 2 factorial design was used to generate 2-dimensional protein maps of mammary tissue extracts. Heifers were reared on 1 of 2 dietary treatments, restricted (650 g/ d of daily gain) or elevated (950 g/d of daily gain) and killed at 1 of 2 body weights (BW, 200 or 350 kg). Cytosolic mammary gland extracts were prepared from frozen mammary parenchyma. Proteome maps of extracts were constructed using PDQuest software. Densities of 820 protein spots were analyzed using the MIXED procedure of SAS. Protein spots were characterized by changes in profiles of expression in response to increased BW, dietary treatment, or both. Dietary treatment influenced the expression of 131 protein spots, whereas heifer BW influenced the expression of 108 spots. The 22 most highly influenced (statistically) spots were excised and submitted for mass spectrometric analyses. Returned protein names and accession numbers were used in National Center for Biotechnology Information database searches to obtain information on the identified proteins. For example, one of the proteins that differed by dietary treatment, transferrin, a binding protein of insulin-like growth factor binding protein-3, was identified via these methods. Possible roles of this and other proteins in mammary development are described. We concluded that a proteomic approach is an effective tool for identifying the proteins involved in bovine mammary development.

Prognostic significance of fascin expression in advanced colorectal cancer: an immunohistochemical study of colorectal adenomas and adenocarcinomas

Background

Fascin is an actin bundling protein with roles in the formation of cell protrusions and motility of mesenchymal and neuronal cells. Fascin is normally low or absent from epithelia, but is upregulated in several epithelial neoplasms where it may contribute to an invasive phenotype. Here, we report on the prevalence and potential clinical significance of fascin expression in relation to the progression of colorectal adenocarcinoma and to tumor cell proliferation as measured by Ki67 index.

Methods

Conventional tissue sections of 107 colorectal adenomas and 35 adenocarcinomas were analyzed by immunohistochemistry for fascin and Ki67 expression.

Fascin expression and Ki67 proliferation index were also investigated by use of a tissue microarray containing cores from a further 158 colorectal adenocarcinomas and 15 adenomas linked to a CCF, IRB-approved database with a mean of 38 months of clinical follow-up. Survival analysis was carried out by the Kaplan-Meier and Cox regression methods.

Results

Fascin was not expressed by the normal colonic epithelium. In conventional sections, 16% of adenomas and 26% of adenocarcinomas showed fascin expression in greater than 10% of the tumor cells. In the clinically-annotated tumors, fascin immunoreactivity was more common in tumors located in the proximal colon (p = 0.009), but was not associated with age, gender, or TNM stage. Patients with stage III/IV adenocarcinomas (n = 62) with strong fascin immunoreactivity had a worse prognosis than patients with low or absent fascin, (3-year overall survival of 11% versus 43% for fascin-negative patients; p = 0.023). In adenomas, fascin and Ki67 tended to be inversely correlated at the cellular level; this trend was less apparent in adenocarcinomas.

Conclusion

Fascin is upregulated in a proportion of adenomas, where its expression is often focal. Strong and diffuse expression was seen in a subset of advanced colorectal adenocarcinomas that correlated with shorter survival in stage III and IV patients. Fascin may have prognostic value as an early biomarker for more aggressive colorectal adenocarcinomas.

Roles of fascin in human carcinoma motility and signaling: prospects for a novel biomarker?

Fascin is a globular actin cross-linking protein that has a major function in forming parallel actin bundles in cell protrusions that are key specialisations of the plasma membrane for environmental guidance and cell migration. Fascin is widely expressed in mesenchymal tissues and the nervous system and is low or absent in adult epithelia. Recent data from a number of laboratories have highlighted that fascin is up-regulated in many human carcinomas and, in individual tissues, correlates with the clinical aggressiveness of tumours and poor patient survival. In cell culture, over-expression or depletion of fascin modulates cell migration and alters cytoskeletal organisation. The identification of biomarkers to provide more effective early diagnosis of potentially aggressive tumours, or identify tumours susceptible to targeted therapies, is an important goal in clinical research. Here, we discuss the evidence that fascin is upregulated in carcinomas, its contributions to carcinoma cell behaviour and its potential as a candidate novel biomarker or therapeutic target.

Fascin-1 expression in papillary and invasive urothelial carcinomas of the urinary bladder

Fascin-1 is an actin-bundling protein that plays an important role in cell motility and adhesion. The level of fascin-1 is low or undetectable in normal epithelial cells. However, overexpression is reported in transformed epithelial cells and in several common types of carcinomas [Bioessays. 2002;24:359-361]. Up-regulation of fascin-1 is associated with higher grades and with aggressive tumors with poorer prognoses. We found no report on the role or the protein expression of fascin-1 in urothelial carcinomas (UCs) of the urinary bladder. In this study, we examined by immunohistochemistry the expression of fascin-1 in the normal human transitional epithelium, benign vesical lesions, and different types of UCs. We found no detectable fascin-1 in the normal transitional epithelium. There was no increase of fascin-1 expression in cystitis cystica, cystitis glandularis, nephrogenic adenoma (n = 10), inverted papilloma (n = 5), and classic exophytic papilloma (n = 4) or in adjacent transitional epithelia associated with these conditions. Patchy or diffusely weak fascin-1 expression was observed in 42% (5/12) of superficial papillary UCs (Ta), and 95% (19/20) of invasive UCs (T2 or higher) demonstrated diffuse strong staining for fascin-1. The microinvasive foci in the lamina propria of UC (T1, n = 8) were also positive for fascin-1, although they were not as strongly stained as in the deeply invasive tumors. Interestingly, the neoplastic cells in the tips of microinvasive carcinomas were distinctly positive for fascin-1. There were significant numbers of fascin-1-positive cells (>50% of the neoplastic cells) in UCs in situ (n = 10). These findings suggest an association between increased fascin-1 expression and increased invasiveness of carcinomas in the urinary bladder.

Prognostic significance of fascin overexpression in human esophageal squamous cell carcinoma

PURPOSE

Fascin, an actin bundling protein, induces membrane protrusions and increased cell motility in various transformed cells. The expression of fascin in epithelial neoplasms has been described only recently, and the role of fascin in esophageal squamous cell carcinoma (ESCC) is still unknown.

EXPERIMENTAL DESIGN

Paraffin sections of 200 patients with ESCC were immunohistochemically investigated. The expression levels of fascin mRNA in 20 ESCC tissues were compared with that in corresponding normal esophageal epithelium by semiquantitative reverse transcription-PCR. We also examined fascin protein expression in 33 ESCC cell lines. The role of fascin in cell motility and invasiveness in ESCC cells was assessed by the vector-based small interfering RNA.

RESULTS

In immunohistochemical study, the intensity of fascin expression was usually increased in the tumor compared with that in normal epithelium. Fascin overexpression was significantly associated with a poor prognosis (immunoreactive rate, P = 0.033; immunoreactive intensity, P = 0.031). The fascin immunoreactive rate was associated with extent of the tumor (P = 0.002) and lymph node metastasis (P = 0.003). Multivariate analysis showed that fascin expression intensity was an independent prognostic factor, but the immunoreactive rate was not. In addition, up-regulation of fascin mRNA was found in 60% (12 of 20) of patients. In vitro study revealed that all 33 ESCC cell lines expressed fascin protein at a certain level. KYSE170, one of the fascin-overexpressed cells, decreased its motile and invasive properties after down-regulation of fascin expression.

CONCLUSION

Our findings suggest that fascin overexpression may play an important role in the progression of ESCC.

Expression of fascin-1, the gene encoding the actin-bundling protein fascin-1, during mouse embryogenesis

Fascin-1 is an actin-bundling protein that contributes to the architecture and function of cell protrusions and microfilaments in cell adhesion, interactions and motility. Fascin-1 has been studied in cultured cells and by biophysical methods, but little is known about its distribution and functions in vertebrate development. As a first step to understanding the role of fascin-1 in embryogenesis, we have characterised the expression pattern of fascin-1 by in situ hybridisation on whole-mount and sectioned mouse embryos from embryonic day (E)8.0-E16.5. Fascin-1 was widely expressed throughout the embryo and the developing nervous system and mesenchymal tissues represented major sites of expression. Intense signals were observed in different regions of the brain, in the spinal cord and retina, and the cranial and dorsal root ganglia (DRG) appeared strongly positive. This neural expression remained strong throughout development. Fascin-1 was also present in the developing somites. High expression was detected in branchial arches and limb bud mesenchyme. At later stages, fascin-1 was expressed in different muscles of the face, skeletal muscles of the body, and in smooth muscle layers of several organs. Limb tendons appeared strongly positive. There was weak expression in heart ventricles. These results show that fascin-1 is principally expressed in neural and mesenchymal derivatives during embryonic development.

Roles of fascin in cell adhesion and motility

Many cell interactions depend on the assembly of cell protrusions; these include cell attachment and migration in the extracellular matrix, cell-cell communication, and the ability of cells to sense their local environment. Cell protrusions are extensions of the plasma membrane that are supported internally by actin-based structures that impart mechanical stiffness. Fascin is a small, globular actin-bundling protein that has emerging roles in diverse forms of cell protrusions and in cytoplasmic actin bundles. The fascin-actin interaction is under complex regulation from the extracellular matrix, peptide factors and other actin-binding proteins. Recent developments advance our understanding of the multifaceted regulation of fascin and the roles of fascin-containing structures in cell adhesion, motility and invasion in the life of vertebrate organisms.

Fascin protrusions in cell interactions

Cell protrusions are outward extensions of the plasma membrane of individual cells that function in sensing the cell environment and in making initial, dynamic adhesions to extracellular matrix and other cells. Cell protrusions can be grouped into two major categories on the basis of morphology: localized, finger-like structures of highly defined shape and various lengths; or broad, irregular extensions of the plasma membrane. A key requirement of all cell protrusions is the need for a rigid cytoskeleton to support the localized extension of the plasma membrane. This is achieved either by a core unipolar bundle of actin microfilaments in finger-like protrusions, or by a combination of radial, rib-like, actin bundles integrated with a dendritic meshwork of microfilaments in the broad, lamellipodial protrusions. From studies of multiple cell types in vertebrates and invertebrates, fascin-1 has emerged as an actin-bundling protein of general importance for a diverse set of cell protrusions with functions in cell adhesion, cell interactions, and cell migration. This review discusses current knowledge of the molecular and cellular properties and functions of fascin, the roles of fascin-based protrusions in the cardiovascular system in health and disease, and areas of future interest.

Mystique is a new insulin-like growth factor-I-regulated PDZ-LIM domain protein that promotes cell attachment and migration and suppresses Anchorage-independent growth

By comparing differential gene expression in the insulin-like growth factor (IGF)-IR null cell fibroblast cell line (R- cells) with cells overexpressing the IGF-IR (R+ cells), we identified the Mystique gene expressed as alternatively spliced variants. The human homologue of Mystique is located on chromosome 8p21.2 and encodes a PDZ LIM domain protein (PDLIM2). GFP-Mystique was colocalized at cytoskeleton focal contacts with alpha-actinin and beta1-integrin. Only one isoform of endogenous human Mystique protein, Mystique 2, was detected in cell lines. Mystique 2 was more abundant in nontransformed MCF10A breast epithelial cells than in MCF-7 breast carcinoma cells and was induced by IGF-I and cell adhesion. Overexpression of Mystique 2 in MCF-7 cells suppressed colony formation in soft agarose and enhanced cell adhesion to collagen and fibronectin. Point mutation of either the PDZ or LIM domain was sufficient to reverse suppression of colony formation, but mutation of the PDZ domain alone was sufficient to abolish enhanced adhesion. Knockdown of Mystique 2 with small interfering RNA abrogated both adhesion and migration in MCF10A and MCF-7 cells. The data indicate that Mystique is an IGF-IR-regulated adapter protein located at the actin cytoskeleton that is necessary for the migratory capacity of epithelial cells.

The Expression of Fascin, an Actin-Bundling Motility Protein, Correlates with Hormone Receptor–Negative Breast Cancer and a More Aggressive Clinical Course

The invasion and metastasis of tumor cells is a major cause of mortality in cancer patients. In the current study, we investigated the expression of fascin, an actin-bundling motility-associated protein, in 210 invasive breast carcinomas with corresponding 5-year clinical follow-up. Fascin expression was compared with hormone receptor (ER/PR) status, HER2 status, cancer grade, cancer stage, metastasis pattern, disease-free survival, and overall survival. Fascin expression was seen in 16% (33/210) of the cases and correlated with ER negativity (22/33, P &lt; 0.001), PR negativity (21/33, P &lt; 0.001), Bloom-Richardson grade 3 (19/29, P &lt; 0.001), and advanced stage (stage 3 or 4, P=0.04).There was no correlation between fascin expression and HER2 status or pattern of metastases. Patients whose tumors were positive for fascin showed both a decreased mean disease-free survival (74.44 versus 100.52 months, P = 0.002) and mean overall survival (77.58 versus 98.98 months, P = 0.002), independent of tumor stage and HER2 status, but not independent of ER/PR status or cancer grade. Given fascin's role in altering cell motility, overexpression may contribute to a more aggressive clinical course in ER/PR-negative breast cancers. If so, then fascin may represent a new molecular target for therapeutic intervention in patients with ER-negative breast cancer.

The prognostic relevance of fascin expression in human gastric carcinoma

OBJECTIVE

Fascin, an actin-bundling protein that is found in membrane ruffles, microspikes, and stress fibers, induces membrane protrusions and increases cell motility in various transformed cells. The expression of fascin in epithelial neoplasms has been described only recently, and its role in gastric cancer is still unknown.

METHODS

Paraffin sections of gastric carcinoma from 214 patients were immunohistochemically investigated using monoclonal antifascin antibody. Staining more than 5% of tumor cells was recorded as positive immunoreactivity.

RESULTS

Overall, fascin immunoreactivity was detected in 54 out of a total of 214 patients (25%). 26 patients were classified as 1+ (5-25% immunoreactive tumor cells) and 28 were 2+ (>25%). In these patients, 7 tumors showed high (>75%) fascin immunoreactivity. Increased immunoreactivity of fascin was sometimes seen at the edge of the tumor. Fascin immunoreactivity was increased according to the extent of primary tumor (p = 0.026). Fascin expression was correlated with age (p = 0.005), serosal invasion (p = 0.013), positive lymph node metastasis (p = 0.006), histopathological grading (p = 0.019), TNM stage (p = 0.003) and recurrence (p = 0.006); however, it was not correlated with distant metastasis (p = 0.108), Lauren's type (p = 0.205), or R classification (p = 0.056). Among 166 patients with T1, T2, T3 or T4, those with fascin-positive tumors had a significantly poorer prognosis than those with fascin-negative tumors (p = 0.029). Multivariate analysis showed that fascin expression was not an independent poor prognostic factor.

CONCLUSION

Our findings suggest that the immunohistochemical detection of fascin could provide useful information as one of the prognostic factors in gastric cancer patients.

Overexpression of profilin reduces the migration of invasive breast cancer cells

The exact role profilin plays in cell migration is not clear. In this study, we have evaluated the effect of overexpression of profilin on the migration of breast cancer cells. Overexpression was carried out by stably expressing GFP-profilin in BT474 cells. It was observed that even a moderate level of overexpression of profilin significantly impaired the ability of BT474 cells to spread on fibronectin-coated substrate and migrate in response to EGF. GFP-profilin expressing cells also showed increased resistance to detachment in response to trypsin and increased tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin compared to the parental and GFP-expressing (control) cell lines. These results suggest that perturbation of profilin levels may offer a good strategy for controlling the metastatic potential of breast cancer cells.

Expression of fascin, an actin-bundling protein, in astrocytomas of varying grades

Malignant astrocytomas are highly infiltrative neoplasms that invade readily into regions of normal brain. On a cellular basis, the motility and invasiveness of human cancers can be ascribed in part to complex rearrangements of the actin cytoskeleton that are governed by several actinbinding proteins. One such actin-binding protein that has been linked to the invasive behavior of carcinomas is fascin, which serves to aggregate F actin into bundles. In this study, we examined the expression of fascin in a series of human malignant astrocytomas (WHO grades I-IV). Five grade I, 5 grade II, 10 grade III, and 26 grade IV human astrocytomas were examined for fascin and glial fibrillary acidic protein (GFAP) expression by double immunofluorescence confocal microscopy. Expression of fascin and GFAP was also determined by Western blot analysis. Fascin expression increased with increasing WHO grade of astrocytoma. This is in marked contrast to GFAP expression, which decreased with increasing WHO grade. In grades I and II neoplasms, and within non-neoplastic brain, fascin and GFAP were expressed diffusely within regions examined. However, in the higher-grade astrocytomas (grades III and IV), fascin and GFAP were expressed regionally in distinctly separate tumor cell populations. This is the first study to demonstrate the expression of fascin in human astrocytic neoplasms. The role that fascin plays in contributing to the invasive phenotype of anaplastic astrocytomas awaits further study and investigation.

Independent value of fascin immunoreactivity for predicting lymph node metastases in typical and atypical pulmonary carcinoids

Immunoreactivity for fascin, an actin-bundling protein related to cell motility, has been reported in breast, ovary, pancreas, skin, and non-small cell carcinomas, and associated with more advanced disease stage and poorer prognosis. Data on pulmonary neuroendocrine (NE) tumors, however, are lacking. We evaluated the expression of fascin by immunohistochemistry--using two different monoclonal antibodies--in surgical specimens of pulmonary NE tumors of all the diverse histological types from 128 consecutive patients recruited between 1987 and 2001, and investigated its relationship with the presence of lymph node metastases. Overall, fascin immunoreactivity was detected in 5% of 38 typical carcinoids (TC), 35% of 23 atypical carcinoids (AC), 83% of 40 large-cell neuroendocrine carcinomas (LCNEC), and 100% of 27 small-cell lung carcinomas (SCLC) (P<0.001), Normal NE cells or hyperplastic NE tumorlets were consistently unreactive. No statistically significant differences in fascin immunoreactivity were found between the two antibodies. In TC and AC but not high-grade NE tumors, fascin immunoreactivity closely correlated with the occurrence of lymph node metastases, the pN class and the number of involved lymph nodes (P<0.001). It was also significantly associated with an increased proliferative activity (Ki-67 labeling index >5%) (P=0.020), and with either down-regulation or altered subcellular compartmentalization of E-cadherin (P<0.001) and CD99 (P=0.030), two cell adhesion complexes in pulmonary NE tumors. At multivariate analysis, only fascin emerged as an independent predictor of lymph node metastases in this tumor group (HR 30.28; 95% confidence intervals: 1.59-574.49; P=0.023). This study indicates that fascin immunoreactivity may identify subsets of pulmonary carcinoid patients with different metastatic potential to regional lymph nodes. Targeting the fascin pathway could be a novel therapeutic strategy of pulmonary carcinoids.

Sustained induction of ERK, protein kinase B, and p70 S6 kinase regulates cell spreading and formation of F-actin microspikes upon ligation of integrins by galectin-8, a mammalian lectin

Galectin-8, a member of the galectin family of mammalian lectins, is a secreted protein that promotes cell adhesion and migration upon binding to a subset of integrins through sugar-protein interactions. Ligation of integrins by galectin-8 triggers a distinct pattern of cytoskeletal organization, including formation of F-actin-containing microspikes. This is associated with activation of integrin-mediated signaling cascades (ERK and phosphatidylinositol 3 kinase (PI3K)) that are much more robust and are of longer duration than those induced upon cell adhesion to fibronectin. Indeed, formation of microspikes is enhanced 40% in cells that overexpress protein kinase B, the downstream effector of PI3K. Inhibition of PI3K activity induced by wortmannin partially inhibits cell adhesion and spreading while largely inhibiting microspike formation in cells adherent to galectin-8. Furthermore, the inhibitory effects of wortmannin are markedly accentuated in cells overexpressing PKB or p70S6K (CHO(PKB) and CHO(p70S6K) cells), whose adhesion and spreading on galectin-8 (but not on fibronectin) is inhibited approximately 25-35% in the presence of wortmannin. The above results suggest that galectin-8 is an extracellular matrix protein that triggers a unique repertoire of integrin-mediated signals, which leads to a distinctive cytoskeletal organization and microspike formation. They further suggest that downstream effectors of PI3K, including PKB and p70 S6 kinase, in part mediate cell adhesion, spreading, and microspike formation induced by galectin-8.

Independent prognostic value of fascin immunoreactivity in stage I nonsmall cell lung cancer

Fascin-1, the most expressed form of fascin in vertebrate tissues, is an actin-bundling protein that induces cell membrane protrusions and increases motility of normal and transformed epithelial cells. Very few data are available on the role of this protein in nonsmall cell lung cancer (NSCLC). Two hundred and twenty patients with stage I NSCLC and long-term follow-up were evaluated immunocytochemically for fascin expression. Overall, variable fascin immunoreactivity was detected in 98% of 116 squamous cell carcinomas, in 78% of 96 adenocarcinomas, in 83% of six large cell carcinomas, and in the two adenosquamous carcinomas under study. Neoplastic emboli were commonly decorated by the antifascin antibody (P<0.001), also when the surrounding invasive carcinoma was unreactive. Fascin immunoreactivity correlated with high tumour grade (P=0.017) and, in adenocarcinomas, with high Ki-67 labelling index (P=0.021). Adenocarcinomas with a prevalent bronchiolo-alveolar in situ component were less commonly immunoreactive for fascin than invasive tumours (P=0.005). Contralateral thoracic or distant metastases were associated significantly with diffuse (>60% immunoreactive tumour cells) fascin expression in adenocarcinomas (P=0.043), and marginally with strong fascin immunostaining in squamous cell carcinomas (P=0.13). No associations were noted with any other clinicopathological variables tested. Patients with tumours showing diffuse (>60% immunoreactive neoplastic cells) and/or strong immunoreactivity for fascin had a shorter survival (P=0.006 for adenocarcinomas and P=0.026 for squamous cell carcinomas), even after multivariate analysis (P=0.014 and 0.050, respectively). The current study documents for the first time that fascin is upregulated in invasive and more aggressive NSCLC, being an independent prognostic predictor of unfavourable clinical course of the disease. Targetting the fascin pathway could be a novel therapeutic strategy of NSCLC.

Fascin, an actin-bundling protein, modulates colonic epithelial cell invasiveness and differentiation in vitro

In epithelial tissue, cell-matrix and cell-cell adhesive interactions have important roles in the normal organization and stabilization of the cell layer. The malignant conversion of epithelial cells involves alterations in the expression and function of these adhesion systems that enable a switch to a migratory phenotype in tumor invasion and metastasis. Fascin is an actin-crosslinking protein that is found in the core actin bundles of cell-surface spikes and projections that are implicated in cell motility. We demonstrate that fascin is not detectable in normal colonic epithelium, but is dramatically up-regulated in colorectal adenocarcinoma. To test the hypothesis that fascin could participate in tumor invasive behavior, we developed a cell culture model to examine the effect of fascin expression on the adhesive interactions, invasiveness, and differentiation of colonic epithelial cells. We report marked effects on the organization of cell-surface protrusions, actin cytoskeleton, and focal adhesions in the absence of alterations in the protein levels of the major components of these structures. These effects correlate with alterations in cell movements on two-dimensional matrix, and increased invasiveness in three-dimensional matrix. The cells also show increased proliferation and decreased capacity for normal glandular differentiation in collagen gels. We propose that up-regulation of fascin, by promoting the formation of protrusive, actin-based, cell-motility structures, could be a significant component in the acquisition of invasive phenotype in colonic carcinoma.

Inflammatory breast cancer: relationship between growth factor signaling and motility in aggressive cancers

A variety of phenotypic characteristics are required for a cancer cell to successfully complete the metastatic cascade. Acquisition of a motile and invasive phenotype is one requirement for a cell to become metastatically competent. The Rho (Ras homology) GTPases are a subfamily of small GTP-binding proteins, which are related to the Ras oncogene. All aspects of cellular motility and invasion are controlled by the Rho GTPases and are closely linked to signals from the extracellular environment, particularly in response to growth factors. Dysregulation of Rho activation through aberrant growth-factor signaling, loss of function of key Rho-regulatory proteins or overexpression of Rho mRNA could result in increased Rho activity and cellular motility. Therefore, the importance of the Rho GTPases in the progression of aggressive cancers, is becoming more appreciated.

Functional role of alpha-actinin, PI 3-kinase and MEK1/2 in insulin-like growth factor I receptor kinase regulated motility of human breast carcinoma cells

Within epithelial tissue, cells are held together by specialized lateral junctions. At particular stages of development and in pathological processes such as metastasis, cells break down the intercellular junctions, separate from the epithelial sheet and migrate individually. Despite the importance of these processes, little is understood about the regulatory mechanisms of active cell separation. In view of the effects of insulin-like growth factor I (IGF-I) on mammary gland development and cancer, we developed a model using MCF-7 human breast cancer cells in which the process of cell separation can be induced by IGF-I. The separation was enhanced in MCF-7 cells overexpressing the IGF-IR and blocked in the cells expressing a dead-kinase mutant of this receptor. Activation of the IGF-IR resulted in a rapid formation of motile actin microspikes at the regions of cell-cell contacts, disorganization of mature adherens junctions and the onset of cell migration. In cell separation, the signaling between the IGF-IR kinase and actin required phosphatidylinositol 3 (PI 3)-kinase-generated phospholipids but not MAP kinases and was mediated by alpha-actinin. The activity of MEK1/2 kinases was needed for consecutive cell migration. This work also defined a new function for alpha-actinin. Upon IGF-IR activation, green fluorescence protein (GFP)-labeled alpha-actinin concentrated at the base of actin microspikes. Deletion of the N-terminal actin-binding domain of alpha-actinin prevented this redistribution, indicating that this domain is necessary. Detection of the C-terminal tail of alpha-actinin reduced the number of microspikes, showing that alpha-actinin has a role in the development of microspikes and is not passively reorganized with filamentous actin. We suggest that the signaling pathway from the IGF-IR kinase through the PI-3 kinase to alpha-actinin participates in the rapid organization of actin into microspikes at the cell-cell junctions and leads to active cell separation, whereas signaling through ERK1/2 MAP kinases controls cell migration following cell separation.

Fascins, and their roles in cell structure and function

The fascins are a structurally unique and evolutionarily conserved group of actin cross-linking proteins. Fascins function in the organisation of two major forms of actin-based structures: dynamic, cortical cell protrusions and cytoplasmic microfilament bundles. The cortical structures, which include filopodia, spikes, lamellipodial ribs, oocyte microvilli and the dendrites of dendritic cells, have roles in cell-matrix adhesion, cell interactions and cell migration, whereas the cytoplasmic actin bundles appear to participate in cell architecture. We discuss the current understanding of the cellular mechanisms that regulate the binding of fascin to actin and how these processes contribute to the organisation or disassembly of cell protrusions. Although the in vivo roles of fascin have been studied principally in Drosophila, several human diseases are associated with inherited or acquired alterations in the expression of fascins. Strategies to modulate fascin-containing protrusions and thereby cell adhesive and migratory behaviour could have potential for therapeutic intervention in these conditions. The supplementary material referred to in this section can be found at http://www.interscience.wiley.com/jpages/0265-9247/suppmat/2002/v24.350.html