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

Fascin actin-bundling protein 1 regulates non-small cell lung cancer progression by influencing the transcription and splicing of tumorigenesis-related genes

Background

High mortality rates are prevalent among patients with non-small-cell lung cancer (NSCLC), and effective therapeutic targets are key prognostic factors. Fascin actin-bundling protein 1 (FSCN1) promotes NSCLC; however, its role as an RNA-binding protein in NSCLC remains unexplored. Therefore, we aimed to explore FSCN1 expression and function in A549 cells.

Method

We screened for alternative-splicing events and differentially expressed genes (DEGs) after FSCN1 silence via RNA-sequencing (RNA-seq). FSCN1 immunoprecipitation followed by RNA-seq were used to identify target genes whose mRNA expression and pre-mRNA alternative-splicing levels might be influenced by FSCN1.

Results

Silencing FSCN1 in A549 cells affected malignant phenotypes; it inhibited proliferation, migration, and invasion, and promoted apoptosis. RNA-seq analysis revealed 2,851 DEGs and 3,057 alternatively spliced genes. Gene ontology-based functional enrichment analysis showed that downregulated DEGs and alternatively splicing genes were enriched for the cell-cycle. FSCN1 promoted the alternative splicing of cell-cycle-related mRNAs involved in tumorigenesis (i.e., BCCIP, DLGAP5, PRC1, RECQL5, WTAP, and SGO1). Combined analysis of FSCN1 RNA-binding targets and RNA-seq data suggested that FSCN1 might affect ACTG1, KRT7, and PDE3A expression by modulating the pre-mRNA alternative-splicing levels of NME4, NCOR2, and EEF1D, that were bound to long non-coding RNA transcripts (RNASNHG20, NEAT1, NSD2, and FTH1), which were highly abundant. Overall, extensive transcriptome analysis of gene alternative splicing and expression levels was performed in cells transfected with FSCN1 short-interfering RNA. Our data provide global insights into the regulatory mechanisms associated with the roles of FSCN1 and its target genes in lung cancer.

Visual analysis of lung neuroendocrine tumors based on CiteSpace knowledge graph

Objective

The relevant literatures in the field of pulmonary neuroendocrine tumor were analyzed to understand the lineage, hot spots and development trends of research in this tumor.

Method

The Web of Science core collection was searched for English-language literature about neuroendocrine tumors of the lung published between 2000 and 2022. CiteSpace software was imported for visualization analysis of countries, institutions, co-cited authors and co-cited journals and sorting of high-frequency keywords, as well as co-cited references and keyword co-occurrence, clustering and bursting display.

Results

A total of 594 publications on neuroendocrine tumours of the lung were available, from 2000 to 2022, with an overall upward trend of annual publications in the literature. Authors or institutions from the United States, Italy, Japan and China were more active in this field, but there was little cooperation among the major countries. Co-cited references and keyword co-occurrence and cluster analysis showed that research on diagnostic instruments, pathogenesis, ectopic ACTH signs, staging and prognosis and treatment was a current research hotspot. The keyword bursts suggested that therapeutic approaches might be a key focus of future research into the field for pulmonary neuroendocrine tumors.

Conclusion

Over these 20 years, research related to neuroendocrine tumors of the lung has increased in fervour, with research on diagnostic instruments, pathogenesis, ectopic ACTH signs, staging and prognosis, and treatment being the main focus of research. Therapeutic treatments may be the future research trend in this field.

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.

MiRNA-145 and Its Direct Downstream Targets in Digestive System Cancers: A Promising Therapeutic Target

MicroRNAs (miRNAs) play a vital role in the onset and development of many diseases, including cancers. Emerging evidence shows that numerous miRNAs have the potential to be used as diagnostic biomarkers for cancers, and miRNA-based therapy may be a promising therapy for the treatment of malignant neoplasm. MicroRNA-145 (miR-145) has been considered to play certain roles in various cellular processes, such as proliferation, differentiation and apoptosis, via modulating the expression of direct target genes. Recent reports show that miR-145 participates in the progression of digestive system cancers, and plays crucial and novel roles in cancer treatment. In this review, we summarize the recent knowledge concerning the function of miR-145 and its direct targets in digestive system cancers. We discuss the potential role of miR-145 as a valuable biomarker for digestive system cancers and how miR-145 regulates these digestive system cancers via different targets to explore the potential strategy of targeting miR-145.

Fascin Inhibitors Decrease Cell Migration and Adhesion While Increase Overall Survival of Mice Bearing Bladder Cancers

Simple Summary

Fascin is an actin-bundling protein, and is highly expressed in metastatic tumor cells. Small molecule fascin inhibitors have been recently developed to block tumor cell migration, invasion, and metastasis. Here we have tested a new fascin inhibitor on bladder cancer cells, and showed the inhibitory effects of the fascin inhibitor on bladder cancer cell migration, adhesion, and primary tumor growth. Therefore, fascin inhibitors might provide clinical benefits to bladder cancer patients.

Abstract

Bladder cancer is one of the most common cancers in the world. Early stage bladder tumors can be surgically removed, but these patients usually have relapses. When bladder cancer becomes metastatic, survival is very low. There is an urgent need for new treatments for metastatic bladder cancers. Here, we report that a new fascin inhibitor decreases the migration and adhesion of bladder cancer cells. Furthermore, this inhibitor decreases the primary tumor growth and increases the overall survival of mice bearing bladder cancers, alone, as well as in combination with the chemotherapy medication, cisplatin, or the immune checkpoint inhibitor, anti-PD-1 antibody. These data suggest that fascin inhibitors can be explored as a new treatment for bladder cancers.

Lung carcinoid tumors with Diffuse Idiopathic Pulmonary NeuroEndocrine Cell Hyperplasia (DIPNECH) exhibit pejorative pathological features

INTRODUCTION

Diffuse Idiopathic Pulmonary NeuroEndocrine Cell Hyperplasia (DIPNECH) is a rare disease often associated with carcinoid tumors. We aimed at evaluating the impact of DIPNECH on characteristics and prognosis of patients who underwent radical treatment of pulmonary carcinoid tumors.

MATERIAL AND METHODS

We reviewed all patients operated on for curative-intent resection of carcinoid tumor in our department from 2001 to 2020. Cases exhibiting both pathological and radiological features of DIPNECH, as assessed by respective thoracic expert physicians, were analyzed separately.

RESULTS

172 cases of resected carcinoid tumors were identified, including 25 (14.5 %) harboring pathological criteria of DIPNECH and radiologic features like mosaic attenuation (92.0 %), multiple nodules < 5 mm (76.0 %), and mucoid impactions (32 %). In DIPNECH patients, major pulmonary resections were usually performed (92.0 %) and resected tumors were mostly classified as pT1 (92 %). Mean Ki67 staining was 3.7 ± 5.2 %. The early postoperative period was mostly uneventful (96.0 %) and 5-year survival was 92.9 ± 6.9 %. Compared to non-DIPNECH cases, we found that patients were older (mean 65.6 ± 9.3 versus 54.1 ± 17.9, p = 0.002), more frequently female (84.0 % versus 56.5 %, p = 0.009), and exhibiting diabetes mellitus (45.8 % versus 18.5 %, p < 0.001) or hypertension (45.8 % versus 24.1 %, p = 0.039). The rate of atypical carcinoid tumors was significantly higher in DIPNECH patients (40.0 % versus 19.9 %, p = 0.027), as well as rate of mediastinal lymph-nodes involvement (pN2+) (36.0 % versus 4.1 %, p < 0.001). At multivariate analysis, only DIPNECH pattern and atypical histology were independent factors of pN2 invasion which was the only predictor of poorer prognosis on Log-Rank test.

CONCLUSION

Carcinoid tumors with proven DIPNECH are associated with negative pathological features and may deserve a dedicated perioperative management.

Large Cell Neuro-Endocrine Carcinoma of the Lung: Current Treatment Options and Potential Future Opportunities

Large-cell neuroendocrine carcinomas of the lung (LCNECs) are rare tumors representing 1-3% of all primary lung cancers. Patients with LCNEC are predominantly male, older, and heavy smokers. Histologically, these tumors are characterized by large cells with abundant cytoplasm, high mitotic rate, and neuroendocrine immunohistochemistry-detected markers (chromogranin-A, synaptophysin, and CD56). In 2015 the World Health Organization classified LCNEC as a distinct subtype of pulmonary large-cell carcinoma and, therefore, as a subtype of non-small cell lung carcinoma (NSCLC). Because of the small-sized tissue samples and the likeness to other neuroendocrine tumors, the histological diagnosis of LCNEC remains difficult. Clinically, the prognosis of metastatic LCNECs is poor, with high rates of recurrence after surgery alone and overall survival of approximately 35% at 5 years, even for patients with early stage disease that is dramatically shorter compared with other NSCLC subtypes. First-line treatment options have been largely discussed but with limited data based on phase II studies with small sample sizes, and there are no second-line well defined treatments. To date, no standard treatment regimen has been developed, and how to treat LCNEC is still on debate. In the immunotherapy and targeted therapy era, in which NSCLC treatment strategies have been radically reshaped, a few data are available regarding these opportunities in LCNEC. Due to lack of knowledge in this field, many efforts have been done for a deeper understanding of the biological and molecular characteristics of LCNEC. Next generation sequencing analyses have identified subtypes of LCNEC that may be relevant for prognosis and response to therapy, but further studies are needed to better define the clinical impact of these results. Moreover, scarce data exist about PD-L1 expression in LCNEC and its predictive value in this histotype with regard to immunotherapy efficacy. In the literature some cases are reported concerning LCNEC metastatic patients carrying driver mutations, especially EGFR alterations, showing targeted therapy efficacy in this setting of disease. Due to the rarity and the challenging understanding of LCNEC, in this review we aim to summarize the management options currently available for treatment of LCNEC.

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.

Inhibition of the proliferation, migration, and invasion of human breast cancer cells by leucine aminopeptidase 3 inhibitors derived from natural marine products

Leucine aminopeptidase 3 is involved in the progression and metastasis of several cancers. This study aimed to screen anti-tumor lead compounds targeting leucine aminopeptidase 3. The compounds' suppression effect on enzyme activity and anti-tumor activity were evaluated through a series of assays. Leucine aminopeptidase 3 overexpression K562 cells were used as an enzyme source to screen 43 natural marine compounds. Compounds 5 and 6 exhibited high suppression effect on leucine aminopeptidase 3 activity. Cell activity tests indicated that both compounds have an anti-proliferative effect on triple-negative breast cancer cells. Wound healing assay and transwell invasion assay showed that both compounds could inhibit the migration and invasion of breast cancer cells. Immunoblot analysis exhibited that both compounds could downregulate the expression of metastasis-related proteins fascin and matrix metalloproteinase-2/9. A molecular dynamic simulation process was applied to discover the key features of compounds 5 and 6 in binding to leucine aminopeptidase 3 active site. This study described the anti-tumor effects of two leucine aminopeptidase 3 small molecule inhibitors. Taken together, compounds 5 and 6 could be used as anti-tumor lead compounds targeting leucine aminopeptidase 3.

Anti-Metastasis Fascin Inhibitors Decrease the Growth of Specific Subtypes of Cancers

Fascin is an actin-bundling protein that is critical for filopodial formation and other cellular cytoskeletal structures. An elevated expression of fascin has been observed in tumor cells and is correlated with a shorter survival of cancer patients. Given its roles in tumor cell migration and invasion, we have developed small-molecule fascin inhibitors to prevent and delay tumor metastasis. Here we report the characterization of a new fascin inhibitor in mice. In addition to its inhibitory effects on tumor metastasis, we also report that fascin inhibitors can decrease the growth of specific subtypes of cancers, including epidermal growth factor receptor (EGFR)-high triple-negative breast cancer, and activated B-cell subtypes of diffuse large B-cell lymphoma. Hence, fascin inhibitors can be used to not only inhibit tumor metastasis, but also decrease the tumor growth of specific cancer types.

How does fascin promote cancer metastasis?

Fascin is an F-actin-bundling protein that cross-links individual actin filaments into straight and stiff bundles. Fascin overexpression in cancer is strongly associated with poor prognosis and metastatic progression across different cancer types. It is well established that fascin plays a causative role in promoting metastatic progression. We will review the recent progress in our understanding of mechanisms underlying fascin-mediated cancer metastasis. This review will cover the biochemical basis for fascin-bundling activity, the mechanisms by which cancer cells upregulate fascin expression and the mechanism underlying fascin-mediated cancer cell migration, invasion, and metastatic colonization. We propose that fascin has broad roles in both metastatic dissemination and metastatic colonization. Understanding these mechanisms will be crucial to the development of anti-metastasis therapeutics targeting fascin.

The use of Ki-67 labeling index to grade pulmonary well-differentiated neuroendocrine neoplasms: current best evidence

Although Ki-67 labeling index (Ki-67%) is not a diagnostic or grading criterion in the World Health Organization classification of pulmonary carcinoid tumor, oncologists often request this test. A survey was administered at a North American Society for Neuroendocrine Tumors meeting to understand how Ki-67% is used in oncologic practices. A systematic literature review was performed to gather best evidence regarding the use of Ki-67%. Consecutive pulmonary carcinoids were stratified into pulmonary typical carcinoids with Ki-67% <5% (group A, n = 187), typical carcinoids with Ki-67% ≥5% (group B, n = 38) and atypical carcinoids irrespective of Ki-67% (group C, n = 31). Overall survival, progression-free survival, recurrence proportions and time to recurrence were compared, by group, using the log-rank test, chi-square statistics and ANOVA, respectively. Our survey confirmed that Ki-67% is frequently used by specialists caring for these patients. Ki-67% of 1-7% significantly correlated with overall survival in the literature but we found no information about Ki-67% cut-off values that would accurately distinguish pulmonary typical from atypical carcinoids or estimate the prognosis of patients stratified by World Health Organization diagnosis and Ki-67% cut-off. Overall survival was significantly different in our 3 patient groups (p < 0.001), with survival probabilities decreasing from groups A to C. Progression-free survival was significantly longer in group A than B (p < 0.007). Our results support the concept that by combining World Health Organization diagnosis and Ki-67%, pulmonary carcinoids can be stratified into 3 grades: G1 (typical carcinoids with Ki-67% <5), G2 (typical carcinoids with Ki-67% ≥5%) and G3 (atypical carcinoids) with different prognoses.

Structural Insights into the Induced-fit Inhibition of Fascin by a Small-Molecule Inhibitor

Tumor metastasis is responsible for ~90% of all cancer deaths. One of the key steps of tumor metastasis is tumor cell migration and invasion. Filopodia are cell surface extensions that are critical for tumor cell migration. Fascin protein is the main actin-bundling protein in filopodia. Small-molecule fascin inhibitors block tumor cell migration, invasion, and metastasis. Here we present the structural basis for the mechanism of action of these small-molecule fascin inhibitors. X-ray crystal structural analysis of a complex of fascin and a fascin inhibitor shows that binding of the fascin inhibitor to the hydrophobic cleft between the domains 1 and 2 of fascin induces a ~35^o rotation of domain 1, leading to the distortion of both the actin-binding sites 1 and 2 on fascin. Furthermore, the crystal structures of an inhibitor alone indicate that the conformations of the small-molecule inhibitors are dynamic. Mutations of the inhibitor-interacting residues decrease the sensitivity of fascin to the inhibitors. Our studies provide structural insights into the molecular mechanism of fascin protein function as well as the action of small-molecule fascin inhibitors.

Classification of pulmonary neuroendocrine tumors: new insights

Neuroendocrine tumors of the lung (Lu-NETs) embrace a heterogeneous family of neoplasms classified into four histological variants, namely typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC). Defining criteria on resection specimens include mitotic count in 2 mm2 and the presence or absence of necrosis, alongside a constellation of cytological and histological traits including cell size and shape, nuclear features and overall architecture. Clinically, TC are low-grade malignant tumors, AC intermediate-grade malignant tumors and SCLC/LCNEC high-grade malignant full-blown carcinomas with no significant differences in survival between them. Homologous tumors arise in the thymus that occasionally have some difficulties in differentiating from the lung counterparts when presented with large unresectable or metastatic lesions. Immunohistochemistry (IHC) helps refine NE diagnosis at various anatomical sites, particularly on small-sized tissue material, in which only TC and small cell carcinoma categories can be recognized easily on hematoxylin & eosin stain, while AC and LCNEC can only be suggested on such material. The Ki-67 labeling index effectively separates carcinoids from small cell carcinoma and may prove useful for the clinical management of a metastatic disease to help the therapeutic decision-making process. Although carcinoids and high-grade neuroendocrine carcinomas in the lung and elsewhere make up separate tumor categories on molecular grounds, emerging data supports the concept of secondary high-grade NETs arising in the preexisting carcinoids, whose clinical and biological relevance will have to be placed into the proper context for the optimal management of these patients. In this review, we will discuss the selected, recent literature with a focus on current issues regarding Lu-NET nosology, i.e., classification, derivation and tumor evolution.

Distinctive pathological and clinical features of lung carcinoids with high proliferation index

Typical (TCs) and atypical carcinoids (ACs) are defined based on morphological criteria, and no grading system is currently accepted to further stratify these entities. The 2015 WHO classification restricts the Ki-67 role to biopsy or cytology samples, rather than for prognostic prediction. We aimed to investigate whether values and patterns of Ki-67 alone would allow for a clinically meaningful stratification of lung carcinoids, regardless of histological typing. Ki-67 proliferation index and pattern (homogeneous versus heterogeneous expression) were assessed in a cohort of 171 TCs and 68 ACs. Cases were subdivided into three Ki-67 ranges (<4/4–9/≥10%). Correlations with clinicopathological data, univariate and multivariate survival analyses were performed. The majority of cases (61.5%) belonged to the <4% Ki-67 range; 25.1 and 13.4% had a proliferation index of 4–9% and ≥10%, respectively. The <4% Ki-67 subgroup was significantly enriched for TCs (83%, p < 0.0001); ACs were more frequent in the subgroup showing Ki-67 ≥ 10% (75%, p < 0.0001). A heterogeneous Ki-67 pattern was preferentially seen in carcinoids with a Ki-67 ≥10% (38%, p < 0.02). Mean Ki-67 values ≥4 and ≥10% identified categories of poor prognosis both in terms of disease-free and overall survival (p = 0.003 and <0.0001). At multivariate analysis, the two thresholds did not retain statistical significance; however, a Ki-67 ≥ 10% identified a subgroup of dismal prognosis even within ACs (p = 0.03) at univariate analysis. Here, we describe a subgroup of lung carcinoids showing brisk proliferation activity within the necrosis and/or mitotic count-based categories. These patients were associated with specific clinicopathological characteristics, to some extent regardless of histological subtyping.

Fascin phosphorylation sites combine to regulate esophageal squamous cancer cell behavior

Filopodia are dynamic membrane extensions generated by F-actin bundling and are involved in cancer cell migration, invasion and metastasis. Fascin is the crucial actin-bundling protein in filopodia, with phosphorylation at fascin serine 39 being well characterized to regulate fascin-mediated actin bundling in filopodia. However, increasing evidence indicates that fascin is phosphorylated at a number of sites. Whether phosphorylation at other sites also regulates fascin function is unknown. In this study, we show that four potential phosphorylation sites in fascin, specifically tyrosine 23, serine 38, serine 39 and serine 274, regulate cell behavior and filopodia formation in esophageal squamous cancer cells. Expression of non-phosphorylatable mutations at each of the four sites promoted anchorage-independent growth, cell motility and filopodia formation, whereas phosphomimetic mutations at each of these sites inhibited these cell behaviors, implying that fascin function in esophageal squamous cancer is regulated by fascin phosphorylation at multiple sites. Furthermore, phosphorylation at S38 and S39 cooperatively regulated cell behavior and filopodia formation, with dual dephosphorylation at both S38 and S39 residues maximally enhancing cell proliferation, migration and filopodia formation, and phosphorylation at any of the two phosphorylatable sites resulting in reduced enhancement. Taken together, our results reveal that phosphorylation at fascin amino acids Y23, S38, S39 and S274, in combination, downregulates the extent of anchorage-independent growth, cell migration and filopodia formation in esophageal squamous cancer cells.

Ki-67 labeling index of neuroendocrine tumors of the lung has a high level of correspondence between biopsy samples and surgical specimens when strict counting guidelines are applied

Optimal histopathological analysis of biopsies from metastases of neuroendocrine tumor (NET) of the lung requires more than morphology only. Additional parameters such as Ki-67 labeling index are required for adequate diagnosis, but few studies have compared reproducibility of different counting protocols and modalities of reporting on biopsies of lung NET. We compared the results of four different manual counting techniques to establish Ki-67 LI. On 47 paired biopsies and surgical specimens from 22 typical carcinoids (TCs), 14 atypical carcinoids (ACs), six large cell neuroendocrine carcinomas (LCNECs), and five small cell carcinomas (SCCs) immunohistochemical staining of Ki-67 antigen was performed. We counted, in regions of highest nuclear staining (HSR), a full ×40-high-power field (diameter = 0.55 mm), 500 or 2000 cells, or 2 mm² surface area, including the HSR or the entire biopsy fragment(s). Mitoses and necrosis were evaluated in an area of 2 mm² or the entire biopsy fragment(s). Between the four counting methods, no differences in Ki-67 LI were observed. However, a Ki-67 LI higher than 5% was found in only four cases when in an HSR, 500 cells were counted (18%), five (23%) when in an HSR 2000 cells were counted, four (18%) when 2 mm² were counted, and one (5%) TC case when the entire biopsy was counted. A 20% cutoff distinguished TC and AC from LCNEC and SCC with 100% specificity and sensitivity, while mitoses and necrosis failed to a large extent. Ki-67 LI in biopsy samples was concordant with that in resection specimens when 2000 cells, 2 mm², or the entire biopsy fragment(s) were counted. Our results are important for clinical management of patients with metastases of a lung NET.

Monoubiquitination Inhibits the Actin Bundling Activity of Fascin

Fascin is an actin bundling protein that cross-links individual actin filaments into straight, compact, and stiff bundles, which are crucial for the formation of filopodia, stereocillia, and other finger-like membrane protrusions. The dysregulation of fascin has been implicated in cancer metastasis, hearing loss, and blindness. Here we identified monoubiquitination as a novel mechanism that regulates fascin bundling activity and dynamics. The monoubiquitination sites were identified to be Lys²⁴⁷ and Lys²⁵⁰, two residues located in a positive charge patch at the actin binding site 2 of fascin. Using a chemical ubiquitination method, we synthesized chemically monoubiquitinated fascin and determined the effects of monoubiquitination on fascin bundling activity and dynamics. Our data demonstrated that monoubiquitination decreased the fascin bundling EC₅₀, delayed the initiation of bundle assembly, and accelerated the disassembly of existing bundles. By analyzing the electrostatic properties on the solvent-accessible surface of fascin, we proposed that monoubiquitination introduced steric hindrance to interfere with the interaction between actin filaments and the positively charged patch at actin binding site 2. We also identified Smurf1 as a E3 ligase regulating the monoubiquitination of fascin. Our findings revealed a previously unidentified regulatory mechanism for fascin, which will have important implications for the understanding of actin bundle regulation under physiological and pathological conditions.

Improving fascin inhibitors to block tumor cell migration and metastasis

Tumor metastasis is the major cause of mortality of cancer patients, being responsible for ∼90% of all cancer deaths. One of the key steps during tumor metastasis is tumor cell migration which requires actin cytoskeletal reorganization. Among the critical actin cytoskeletal protrusion structures are antenna-like filopodia. Fascin protein is the main actin-bundling protein in filopodia. Here we report the development of fascin-specific small-molecules that inhibit the interaction between fascin and actin. These inhibitors block the in vitro actin-binding and actin-bundling activities of fascin, tumor cell migration and tumor metastasis in mouse models. Mechanistically, these inhibitors likely occupy one of the actin-binding sites, reduce the binding of actin filaments, and thus lead to the inhibition of the bundling activity of fascin. At the cellular level, these inhibitors impair actin cytoskeletal reorganization. Our data indicate that target-specific anti-fascin agents will have great potential for treating metastatic tumors.

Fascin1 in carcinomas: Its regulation and prognostic value

Previous cell biological studies demonstrate that the actin bundling protein fascin1 regulates cell motility, migration and invasion. Human studies demonstrate that fascin1 is upregulated in many epithelial cancers. This review gives a brief overview of the role of fascin1 in cell migration and invasion, but focuses mainly on the regulation and clinical relevance of fascin1 in epithelial cancers. Here, we propose fascin1 as a potent prognostic biomarker for breast, colorectal, esophageal cancers and head and neck squamous cell carcinomas. Fascin1 may also be an attractive drug target against these carcinomas in the future, but more studies are needed.

What clinicians are asking pathologists when dealing with lung neuroendocrine neoplasms?

Lung neuroendocrine tumors (NET) are currently classified in resection specimens according to four histological categories, namely typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Diagnostic criteria have remained unchanged in the 2015 WHO classification, which has ratified the wide acceptance and popularity of such terminology in the pathologists׳ and clinicians׳ community. A unifying umbrella of NE morphology and differentiation has been recognized in lung NET, which has pushed to enter an unique box of invasive tumors along with diffuse idiopathic pulmonary NE cell hyperplasia (DIPNECH) as a pre-invasive lesion with a potential toward the development of carcinoids. However, uncertainties remain in the terminology of lung NET upon small samples, where Ki-67 antigen could play some role to avoid misdiagnosing carcinoids as high-grade NE tumors. Epidemiologic, clinical and genetic traits support a biological three-tier over a pathology four-tier model, according to which TC are low malignancy tumors, AC intermediate malignancy tumors and LCNEC/SCC high malignancy tumors with no significant differences in survival among them. Inconsistencies in diagnostic reproducibility, troubles in the therapy of AC and LCNEC, and limitations to histology within the same tumor category argue in favor of a global re-thinking of lung NET where a grading system could play a role. This review outlines three main key questions in the field of lung NET: (A) unbiased diagnoses, (B) the role of Ki-67 and tumor grading, and (C) management of predictive markers. Answers are still inconclusive, thus additional research is required to improve our understanding on lung NET.

Expression of Fascin-1 on human lung cancer and paracarcinoma tissue and its relation to clinicopathological characteristics in patients with lung cancer

BACKGROUND

Lung cancer poses a severe threat to human life. Biomarkers of cancers are helpful in the diagnosis and treatment of patients with cancers. Biomarkers of lung cancers are rare, and thus deserve further research.

OBJECTIVE

The objective of the present study was to explore the expression of Fascin-1 in human lung cancer and paracarcinoma tissue, its correlation with clinicopathological characteristics in patients with lung cancer, and study the possible relationship between Fascin-1 expression and clinical-biological behavior of lung cancer.

METHOD

This study used the MaxVision two-step immunohistochemical detection method to detect Fascin-1 expression in 84 of lung cancer and paracarcinoma tissues. This study set the expression of Fascin-1 in vascular endothelial cells as the positive control, and used phosphate buffered saline (replacing the primary antibodies) as negative control.

RESULT

Of all the 84 lung cancer tissues and paracarcinoma tissues, positive expression of the Fascin-1 protein were detected in 78 cases (92.9%) and 27 cases (32.1%), respectively, and the difference was statistically significant (P<0.05). Differences in Fascin-1 expression between different age groups, clinical stages, and lymph node metastases were statistically significant (P<0.05), while differences in Fascin-1 expression between sexes, tumor stages, and pathological types demonstrated no statistical significance (P>0.05). The survival times of the patients with different Fascin-1 protein-positive expressions in lung cancer tissues were statistically significant (P>0.05), while the survival times of the patients with different Fascin-1 protein-positive expressions in paracarcinoma tissues were not statistically significant (P>0.05).

CONCLUSION

In lung cancer, Fascin-1 expression was closely related to tumor invasion and metastasis, and the difference in expression of Fascin-1 had a significant effect on the survival time of the lung cancer patients. Therefore, Fascin-1 might be expected to serve as a possible potential biomarker of lung cancer.

Targeted inhibition of fascin function blocks tumour invasion and metastatic colonization

One of the key steps during tumour metastasis is tumour cell migration and invasion, which require actin cytoskeletal reorganization. Among the critical actin cytoskeletal protrusion structures are the filopodia, which act like cell sensory organs to communicate with the extracellular microenvironment and participate in fundamental cell functions such as cell adhesion, spreading and migration in the three-dimensional environment. Fascin is the main actin-bundling protein in filopodia. Using high-throughput screening, here we identify and characterize small molecules that inhibit the actin-bundling activity of fascin. Focusing on one such inhibitor, we demonstrate that it specifically blocks filopodial formation, tumour cell migration and invasion in vitro, and metastasis in vivo. Hence, target-specific anti-fascin agents have a therapeutic potential for cancer treatment.

Ki-67 antigen in lung neuroendocrine tumors: unraveling a role in clinical practice

Classification of lung neuroendocrine (NE) tumors is a step-wise process with four tumor categories being identified by morphology, namely typical carcinoid (TC), atypical carcinoid, large-cell NE carcinoma, and small-cell lung carcinoma (SCLC). Ki-67 antigen or protein (henceforth simply Ki-67) has been largely studied in these tumors, but the clinical implications are so far not clear. A well-defined role has regarded the diagnostic use in the separation of TC and AC from SCLC in nonsurgical specimens, with monoclonal antibody MIB-1 resulting in the most used reagent after antigen retrieval procedures. Uncertainties, however, have arisen in its assessment, usually expressed as Ki-67 labeling index, because of some variability in obtaining either value of the fraction. A diagnostic role is currently lacking, even though there are significant differences in most cases between TC and AC, less so between large-cell NE carcinoma and SCLC. In addition, the prognostic role of Ki-67 is debated, likely due to methodological and biological reasons. The last challenge would be to identify an effective lung-specific grading system based on Ki-67 labeling index. In this review article, five relevant issues to Ki-67 have been addressed by using a question-answer methodology, with relevant key points discussing major interpretation issues. The conclusion is that Ki-67 is a feasible and potentially meaningful marker in lung NE tumors, but more data are needed to determine its ideal function in this setting of tumors.

Conditional expression of fascin increases tumor progression in a mouse model of intestinal cancer

While absent from normal epithelia, an actin bundling protein, fascin, becomes expressed in invasive carcinoma of different origins. It is highly enriched at the tumors' invasive front suggesting that it could play a role in cancer invasion. Multiple studies have shown that fascin, through its role in formation of cellular protrusions such as filopodia and invadopodia, enhances cancer cell migration and invasion in vitro. However, the role of fascin in vivo remains unknown. We have generated a compound transgenic mouse model that allows expression of fascin in the intestinal epithelium in the Apc-mutated background. Conditional expression of fascin led to decrease in mice survival and increase in tumor burden compared to control animals. Induction of fascin expression in adult tumor-bearing animals accelerated tumor progression and led to formation of invasive adenocarcinoma. Altogether, our study shows that fascin can promote tumor progression in vivo, but also unravels an unexpected role of fascin in tumor initiation.

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.

Association of fascin-1 with mortality, disease progression and metastasis in carcinomas: a systematic review and meta-analysis

BACKGROUND

Fascin-1 is an actin-bundling protein expressed in many human carcinomas, although absent from most normal epithelia. Fascin-1 promotes filopodia formation, migration and invasion in carcinoma cells; in mouse xenograft tumor models it contributes to metastasis. Fascin-1 is an interesting candidate biomarker for aggressive, metastatic carcinomas but data from individual studies of human tumors have not yet been pooled systematically.

METHODS

This systematic review was conducted in accordance with PRISMA guidelines, using fixed and random effects models, as appropriate, to undertake meta-analysis.

RESULTS

A total of 26 immunohistochemical studies of 5 prevalent human carcinomas were identified for meta-analysis. Fascin-1 was associated with increased risk of mortality for breast (pooled hazard ratio, (HR) = 2.58; 95% confidence interval (CI) 1.48 to 4.52; P = 0.001), colorectal (HR = 1.60 (1.37 to 1.86; P <0.001) and esophageal carcinomas (HR = 1.35; CI 1.13 to 1.60; P = 0.001). There was no evidence of association of fascin-1 with mortality in gastric and lung carcinomas. Fascin-1 was associated with increased risk of disease progression in breast (HR = 2.48; CI 1.38 to 4.46; P = 0.002) and colorectal carcinomas (HR = 2.12; CI 1.00 to 4.47; P = 0.05), but not with progression of lung carcinomas (HR = 0.95; CI 0.49 to 1.85; P = 0.9). Fascin-1 was associated with increased risk of lymph node metastasis in colorectal (pooled risk ratio (RR) = 1.47; CI 1.26 to 1.71; P <0.001) and gastric carcinomas (RR = 1.43; CI 1.21 to 1.70; P <0.001). There was no evidence of association of fascin-1 with lymph node metastasis in lung or esophageal carcinomas. Fascin-1 was associated with increased risk of distant metastasis in colorectal (RR = 1.70; CI 1.18 to 2.45; P = 0.004) and gastric carcinomas (RR = 1.93; CI 1.21 to 3.33; P = 0.02). No association with distant metastasis in esophageal carcinomas was observed. Pooling across all the carcinomas provided strong evidence for association of fascin-1 with increased risk of mortality (HR = 1.44; CI 1.24 to 1.68; P <0.001; n = 3,645), lymph node metastasis (RR = 1.36; CI 1.18 to 1.55; P <0.001; n = 2,906) and distant metastasis (1.76; 1.34 to 2.32; P <0.001; n = 1,514).

CONCLUSIONS

Fascin-1 is associated consistently with increased risk of mortality in breast, colorectal and esophageal carcinomas and with metastasis in colorectal and gastric carcinomas. The results were stable to various sensitivity analyses and did not vary by predefined subgroups. These data will assist rational decision making for focusing investigations of fascin-1 as a biomarker or therapeutic target onto the most relevant carcinomas.

Molecular mechanism of fascin function in filopodial formation

Filopodia are cell surface protrusions that are essential for cell migration. This finger-like structure is supported by rigid tightly bundled actin filaments. The protein responsible for actin bundling in filopodia is fascin. However, the mechanism by which fascin functions in filopodial formation is not clear. Here we provide biochemical, cryo-electron tomographic, and x-ray crystal structural data demonstrating the unique structural characteristics of fascin. Systematic mutagenesis studies on 100 mutants of fascin indicate that there are two major actin-binding sites on fascin. Crystal structures of four fascin mutants reveal concerted conformational changes in fascin from inactive to active states in the process of actin bundling. Mutations in any one of the actin-binding sites impair the cellular function of fascin in filopodial formation. Altogether, our data reveal the molecular mechanism of fascin function in filopodial formation.

Limited role of Ki-67 proliferative index in predicting overall short-term survival in patients with typical and atypical pulmonary carcinoid tumors

Pulmonary carcinoid tumors are currently classified as typical or atypical based on the mitotic index (2 per 10 hpf) and/or the presence of necrosis. Following incorporation of the Ki-67 index into the classification of GI carcinoid tumors, our oncologists have also been requesting this test as part of the work-up of pulmonary carcinoid tumors although there are currently no established criteria for interpreting Ki-67 index in these neoplasms. We utilized the Ariol(®) SL50 Image Analyzer system to measure the Ki-67 index in 101 pulmonary carcinoid tumors (78 typical and 23 atypical) and then correlated the Ki-67 index and the histological diagnoses in univariate and multivariable analysis with overall survival. The mean Ki-67 indices for the typical carcinoids (3.7 s.d.± 4.0) and the atypical carcinoids (18.8 s.d.± 17.1) were significantly different (P<0.001) although the frequency distributions of Ki-67 indices in the two groups overlapped considerably. Receiver operating characteristic curve analysis showed that a Ki-67 index cutoff value of 5% provided the best fit for specificity and sensitivity in predicting overall survival. Histological diagnosis and the Ki-67 index cutoff of 5% were each independently strong predictors of survival (P<0.001 and P=0.003, respectively). When considered together in multivariable analysis, histological diagnosis was the stronger predictor of overall survival and a Ki-67 index cutoff of 5% did not provide additional significant predictive survival information within either the typical carcinoid or the atypical carcinoid patient group. A few typical carcinoid patients with Ki-67 indices of 5% appeared to have worse survival after 5 years than those with Ki-67 indices <5%, but the data set was insufficiently powered to further analyze this. These findings do not provide best evidence for the routine use of Ki-67 index to prognosticate overall short-term survival in patients with pulmonary carcinoid tumors.

Molecular and cellular biology of neuroendocrine lung tumors: evidence for separate biological entities

Pulmonary neuroendocrine tumors (NETs) are traditionally described as comprising a spectrum of neoplasms, ranging from low grade typical carcinoids (TCs) via the intermediate grade atypical carcinoids (ACs) to the highly malignant small cell lung cancers (SCLCs) and large cell neuroendocrine carcinomas (LCNECs). Recent data, however, suggests that two categories can be distinguished on basis of molecular and clinical data, i.e. the high grade neuroendocrine (NE) carcinomas and the carcinoid tumors. Bronchial carcinoids and SCLCs may originate from the same pulmonary NE precursor cells, but a precursor lesion has only been observed in association with carcinoids, termed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. The occurrence of mixed tumors exclusively comprising high grade NE carcinomas also supports a different carcinogenesis for these two groups. Histopathologically, high grade NE lung tumors are characterized by high mitotic and proliferative indices, while carcinoids are defined by maximally 10 mitoses per 2mm(2) (10 high-power fields) and rarely have Ki67-proliferative indices over 10%. High grade NE carcinomas are chemosensitive tumors, although they usually relapse. Surgery is often not an option due to extensive disease at presentation and early metastasis, especially in SCLC. Conversely, carcinoids are often insensitive to chemo- and radiation therapy, but cure can usually be achieved by surgery. A meta-analysis of comparative genomic hybridization studies performed for this review, as well as gene expression profiling data indicates separate clustering of carcinoids and carcinomas. Chromosomal aberrations are much more frequent in carcinomas, except for deletion of 11q, which is involved in the whole spectrum of NE lung tumors. Deletions of chromosome 3p are rare in carcinoids but are a hallmark of the high grade pulmonary NE carcinomas. On the contrary, mutations of the multiple endocrine neoplasia type 1 (MEN1) gene are restricted to carcinoid tumors. Many of the differences between carcinoids and high grade lung NETs can be ascribed to tobacco consumption, which is strongly linked to the occurrence of high grade NE carcinomas. Smoking causes p53 mutations, very frequently present in SCLCs and LCNECs, but rarely in carcinoids. It further results in other early genetic events in SCLCs and LCNECs, such as 3p and 17p deletions. Smoking induces downregulation of E-cadherin and associated epithelial to mesenchymal transition. Also, high grade lung NETs display higher frequencies of aberrations of the Rb pathway, and of the intrinsic and extrinsic apoptotic routes. Carcinoid biology on the other hand is not depending on cigarette smoke intake but rather characterized by aberrations of other specific genetic events, probably including Menin or its targets and interaction partners. This results in a gradual evolution, most likely from proliferating pulmonary NE cells via hyperplasia and tumorlets towards classical carcinoid tumors. We conclude that carcinoids and high grade NE lung carcinomas are separate biological entities and do not comprise one spectrum of pulmonary NETs. This implies the need to reconsider both diagnostic as well as therapeutic approaches for these different groups of malignancies.

The cluster of miR-143 and miR-145 affects the risk for esophageal squamous cell carcinoma through co-regulating fascin homolog 1

MicroRNAs (miRNAs), 18–24 nt non-coding RNAs, are thought to play important roles in cell proliferation, differentiation, apoptosis, and development. Recent studies suggest that some of the known microRNAs map to a single genomic locale within a single polycistronic transcript. But the roles of the cluster remain to be known. In order to understand the role and mechanism of a cluster of miR-143 and miR-145 in esophageal squamous cell carcinoma (ESCC), the association of mature miR-143 and miR-145 expression with the risk for esophageal cancer was evaluated in ESCC patients with a case-control study, and target protein regulated by mature miRNA was analyzed in ESCC cell lines with 3′UTR luciferase reporter assay. The expression levels of miR-143 and miR-145 were determined in 110 pairs of esophageal cancer tissues and adjacent normal tissues using real-time reverse transcription PCR. The relative expression of miR-143 and miR-145 were statistically different between cancer tissues and matched controls. The combined expression of miR-143 and miR-145 was significantly associated with the risk for esophageal cancer. Meanwhile, the reduced expression of two miRNAs in tumor patient was supposed to have a trend of lymph node metastases. The co-expression pattern of miR-143 and miR-145 was analyzed with Pearson correlation. It showed a significant correlation between these two miRNAs expression both in tissues and tumor cell lines. 3′UTR luciferase reporter assay indicated that Fascin Homolog 1 (FSCN1) could be co-regulated by miR-143 and miR-145. The protein level of FSCN1 showed no significant linear correlation with miR-143 and miR-145 expression in ESCC cell lines with Western blotting analysis. In conclusion, since miR-143 and miR-145 could regulate oncogenic FSCN1 and take part in the modulation of metastases, the result suggested the combination variable of miR-143 and miR-145 as a potential biomarker for earlier diagnosis and prognosis of esophageal cancer.

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.

Fascin overexpression promotes neoplastic progression in oral squamous cell carcinoma

BACKGROUND

Fascin is a globular actin cross-linking protein, which plays a major role in forming parallel actin bundles in cell protrusions and is found to be associated with tumor cell invasion and metastasis in various type of cancers including oral squamous cell carcinoma (OSCC). Previously, we have demonstrated that fascin regulates actin polymerization and thereby promotes cell motility in K8-depleted OSCC cells. In the present study we have investigated the role of fascin in tumor progression of OSCC.

METHODS

To understand the role of fascin in OSCC development and/or progression, fascin was overexpressed along with vector control in OSCC derived cells AW13516. The phenotype was studied using wound healing, Boyden chamber, cell adhesion, Hanging drop, soft agar and tumorigenicity assays. Further, fascin expression was examined in human OSCC samples (N = 131) using immunohistochemistry and level of its expression was correlated with clinico-pathological parameters of the patients.

RESULTS

Fascin overexpression in OSCC derived cells led to significant increase in cell migration, cell invasion and MMP-2 activity. In addition these cells demonstrated increased levels of phosphorylated AKT, ERK1/2 and JNK1/2. Our in vitro results were consistent with correlative studies of fascin expression with the clinico-pathological parameters of the OSCC patients. Fascin expression in OSCC showed statistically significant correlation with increased tumor stage (P = 0.041), increased lymph node metastasis (P = 0.001), less differentiation (P = 0.005), increased recurrence (P = 0.038) and shorter survival (P = 0.004) of the patients.

CONCLUSION

In conclusion, our results indicate that fascin promotes tumor progression and activates AKT and MAPK pathways in OSCC-derived cells. Further, our correlative studies of fascin expression in OSCC with clinico-pathological parameters of the patients indicate that fascin may prove to be useful in prognostication and treatment of OSCC.

Differential protein expression profiles in estrogen receptor-positive and -negative breast cancer tissues using label-free quantitative proteomics

Identification of the proteins that are associated with estrogen receptor (ER) status is a first step towards better understanding of the hormone-dependent nature of breast carcinogenesis. Although a number of gene expression analyses have been conducted, protein complement has not been systematically investigated to date. Because proteins are primary targets of therapeutic drugs, in this study, we have attempted to identify proteomic signatures that demarcate ER-positive and -negative breast cancers. Using highly enriched breast tumor cells, replicate analyses from 3 ERα+ and 3 ERα- human breast tumors resulted in the identification of 2,995 unique proteins with ≥2 peptides. Among these, a number of receptor tyrosine kinases and intracellular kinases that are abundantly expressed in ERα+ and ERα- breast cancer tissues were identified. Further, label-free quantitative proteome analysis revealed that 236 proteins were differentially expressed in ERα+ and ERα- breast tumors. Among these, 141 proteins were selectively up-regulated in ERα+, and 95 proteins were selectively up-regulated in ERα- breast tumors. Comparison of differentially expressed proteins with a breast cancer database revealed 98 among these have been previously reported to be involved in breast cancer. By Gene Ontology molecular function, dehydrogenase, reductase, cytoskeletal proteins, extracellular matrix, hydrolase, and lyase categories were significantly enriched in ERα+, whereas selected calcium-binding protein, membrane traffic protein, and cytoskeletal protein were enriched in ERα- breast tumors. Biological process and pathway analysis revealed that up-regulated proteins of ERα+ were overrepresented by proteins involved in amino acid metabolism, proteasome, and fatty acid metabolism, while up-regulated proteins of ERα- were overrepresented by proteins involved in glycolysis pathway. The presence and relative abundance of 4 selected differentially abundant proteins (liprin-α1, fascin, DAP5, and β-arrestin-1) were quantified and validated by immunohistochemistry. In conclusion, unlike in vitro cell culture models, the in vivo signaling proteins and pathways that we have identified directly from human breast cancer tissues may serve as relevant therapeutic targets for the pharmacological intervention of breast cancer.

Fascin, an actin-bundling protein, promotes breast cancer progression in vitro

Fascin, an actin-cross-linking protein, is up-regulated in breast cancer and correlates with a more aggressive disease. This study was conducted to elucidate the effects of manipulating fascin in breast cancer cells on the metastasis-associated events, including proliferation, adhesion, invasion, epithelial-mesenchymal transition (EMT) and enrichment of a CD44(+) /CD24(-) subpopulation that show some stem/progenitor cell properties. Western blot analysis of a panel of breast cancer cell lines revealed high expression of fascin in MDA-MB-435 and MDA-MB-231 cells but revealed no or low expression in MDA-MB-453, Her-18 and T47D. Gain-of-function and loss-of-function studies in breast cancer cells demonstrated that forced expression of fascin promoted cell proliferation assessed by the MTT assay, decreased cellular adhesion to fibronectin and potentiated the invasive capacity in the Transwell chamber invasion assay. Conversely, down-regulation of fascin via small interfering RNA increased cell adhesion and facilitated cell proliferation and invasion. In addition, fascin participated in the EMT and modulated the proportion of the CD44(+) /CD24(-) subpopulation in breast cancer cells. In conclusion, our data highlight an important role for fascin in breast cancer progression in vitro through orchestrating a variety of cellular events associated with metastasis, and thus, targeting this gene might have therapeutic implications.

Fascin protein is critical for transforming growth factor β protein-induced invasion and filopodia formation in spindle-shaped tumor cells

Fascin, an actin-bundling protein overexpressed in all carcinomas, has been associated with poor prognosis, shorter survival, and more metastatic diseases. It is believed that fascin facilitates tumor metastasis by promoting the formation of invasive membrane protrusions. However, the mechanisms by which fascin is overexpressed in tumors are not clear. TGFβ is a cytokine secreted by tumor and mesenchymal cells and promotes metastasis in many late stage tumors. The pro-metastasis mechanisms of TGFβ remain to be fully elucidated. Here we demonstrated that TGFβ induced fascin expression in spindle-shaped tumor cells through the canonical Smad-dependent pathway. Fascin was critical for TGFβ-promoted filopodia formation, migration, and invasion in spindle tumor cells. More importantly, fascin expression significantly correlates with TGFβ1 and TGFβ receptor I levels in a cohort of primary breast tumor samples. Our results indicate that elevated TGFβ level in the tumor microenvironment may be responsible for fascin overexpression in some of the metastatic tumors. Our data also suggest that fascin could play a central role in TGFβ-promoted tumor metastasis.

Prognostic impact of fascin-1 expression is more significant in advanced colorectal cancer

BACKGROUND

Fascin-1 is not expressed in normal colorectal epithelium, but is up-regulated in colorectal cancer. However, its exact biological mechanism remains unknown. The purpose of this study was to investigate the relationship of fascin-1 expression with the clinicopathologic parameters and its prognostic impact in advanced colorectal cancer.

MATERIALS AND METHODS

The immunohistochemical stainings for fascin-1, β-catenin, and Ki-67 labeling index were performed with 126 stage III colorectal cancer specimens.

RESULTS

Fascin-1 was found to be expressed in 74 (58.7%) of the 126 colorectal cancer specimens. Five-year survival rate was significantly low, whereas the distant recurrence rate was significantly high in patients with fascin-positive stage III colorectal cancer. There was no significant correlation between fascin-1 expression and clinicopathologic factors such as tumor size, nodal metastasis, pathologic stage, β-catenin expression, and Ki-67 labeling index. However, fascin-1 expression was an independent prognostic factor in multivariate analysis. Patients with N1 showed no significant difference in 5-y DFS and OS according to the fascin-1 expression (79.0% versus 60.5%, P = 0.113; 86.5% versus 78.8%, P = 0.566). Patients with N2 showed marginal difference in 5-y DFS and significant difference in 5-y OS according to the fascin-1 expression (59.4% versus 32.4%, P = 0.088; 81.2% versus 39.5%, P = 0.002).

CONCLUSIONS

This study suggests that fascin-1 expression in colorectal cancer may be clinically useful in predicting distant metastasis and poor survival, and we demonstrated that fascin-1 expression and N stage are significant independent prognostic factors for survival of colorectal cancer patients.

Effects of small interfering RNAs targeting fascin on human esophageal squamous cell carcinoma cell lines

BACKGROUND

Fascin induces membrane protrusions and cell motility. Fascin overexpression was associated with poor prognosis, and its downregulation reduces cell motility and invasiveness in esophageal squamous cell carcinoma (ESCC). Using a stable knockdown cell line, we revealed the effect of fascin on cell growth, cell adhesion and tumor formation.

METHODS

We examined whether fascin is a potential target in ESCC using in vitro and in vivo studies utilizing a specific siRNA. We established a stable transfectant with downregulated fascin from KYSE170 cell line.

RESULTS

The fascin downregulated cell lines showed a slower growth pattern by 40.3% (p < 0.01) and detachment from collagen-coated plates by 53.6% (p < 0.01), compared to mock cells, suggesting that fascin plays a role in cell growth by maintaining cell adhesion to the extracellular matrix. In vivo, the tumor size was significantly smaller in the tumor with fascin knockdown cells than in mock cells by 95% at 30 days after inoculation.

CONCLUSIONS

These findings suggest that fascin overexpression plays a role in tumor growth and progression in ESCC and that cell death caused by its downregulation might be induced by cell adhesion loss. This indicates that targeting fascin pathway could be a novel therapeutic strategy for the human ESCC.

Fascin expression predicts survival after potentially curative resection of node-positive colon cancer

Fascin, an actin-bundling protein, is expressed in many neoplasms including colorectal cancer. It is considered to be a mediator of tumor cell invasion and an indicator of aggressive phenotype; however, there are few reports on the association between fascin and prognosis in colorectal cancer. The aims of this study were to: (a) investigate the expression of fascin in the central part of the tumor and at the invasive front in patients who had a potentially curative resection for node-positive colonic carcinoma; (b) examine the method of scoring fascin expression; and (c) investigate the association between fascin expression and overall survival and other clinicopathologic features. Fascin expression was assessed by immunostaining of microarrays from archived tissue of 470 patients who were followed for a minimum of 5 years after resection. Other clinicopathologic data had been recorded prospectively according to a standardized protocol. Analysis of overall survival was by the Kaplan-Meier method and Cox regression. For both central tumor tissue and the invasive front, it was found that the percentage of stained cells was a sufficient measure of fascin expression in relation to survival, with staining intensity providing no significant additional information. At both levels, there was a significant independent association between high fascin expression and diminished survival, although this association was much stronger in the central region (adjusted hazard ratio 1.6, P<0.001) than at the invasive front (adjusted hazard ratio 1.1, P=0.044). Fascin expression predicted overall survival but did not displace other routinely collected clinicopathologic predictors.

Migrastatin analogues target fascin to block tumour metastasis

Tumour metastasis is the primary cause of death of cancer patients. Development of new therapeutics preventing tumour metastasis is urgently needed. Migrastatin is a natural product secreted by Streptomyces, and synthesized migrastatin analogues such as macroketone are potent inhibitors of metastatic tumour cell migration, invasion and metastasis. Here we show that these migrastatin analogues target the actin-bundling protein fascin to inhibit its activity. X-ray crystal structural studies reveal that migrastatin analogues bind to one of the actin-binding sites on fascin. Our data demonstrate that actin cytoskeletal proteins such as fascin can be explored as new molecular targets for cancer treatment, in a similar manner to the microtubule protein tubulin.

Knockdown of fascin1 expression suppresses the proliferation and metastasis of gastric cancer cells

AIMS

Our current investigation attempts to study the role of the fascin1 gene in growth and metastasis of gastric cancer cell line MKN45.

METHODS

Small interfering RNA (siRNA) was used to inhibit fascin1 expression in the human gastric cancer cell line MKN45. Expression of fascin1 in fascin1 siRNA transfected cells (sifascin1), non-transfected cells (NT) and non-specific fascin1 siRNA cells (CON) were examined by Western blotting and reverse transcription polymerase chain reaction (RT-PCR). Cell growth ability in vitro was evaluated by MTT and clone formation assays. Cell mobility in vitro was examined by the Boyden chamber assay. Nude mice metastasis models were established by abdominal cavity transfer method. Tumour growth was evaluated by immunohistochemistry with proliferating cell nuclear antigen (PCNA).

RESULTS

Knockdown of fascin1 expression in MKN45 cells resulted in decreased cellular proliferative and migratory abilities. In vitro, the cloning efficiency of siFascin1 cells (34.2%) was significantly lower compared to that in NT (78.5%) (p < 0.05). The migration rate in siFascin1 cells was significantly decreased (33.7%) compared with NT cells (89.4%) (p < 0.05). In vivo, the cell proliferation rate was lower in siFascin1 cells (25.8%) compared to that in NT (75.0%) (p < 0.05). The number of tumour clones in the liver was significantly lower in siFascin1 cells (2.0 +/- 1.1) compared to that in NT (5.1 +/- 1.6) (p < 0.05).

CONCLUSIONS

Our study demonstrates that down-regulation of fascin1 suppresses the proliferation and migration of gastric cancer cells MKN45, suggesting that fascin1 siRNA may offer a novel potential gene therapy approach for human gastric cancer with fascin1 over-expression.

Fascin expression in colorectal carcinomas

PURPOSE

The purpose of this study was to investigate the significance of fascin expression in colorectal carcinoma.

METHODS

This is a retrospective study of 167 consecutive, well-documented cases of primary colorectal adenocarcinoma for which archival material of surgical specimens from primary tumor resections were available. We chose a representative tissue sample block and examined fascin expression by immunohistochemistry using a primary antibody against "fascin". We calculated the "immunohistochemical score (IHS)" of fascin for each case, which was calculated from the multiplication of scores for the percentage of stained cells and the staining intensity.

RESULTS

Fascin immunoreactivity was observed in 59 (35.3%) of all cases with strong reactivity in 24 (14.4%), moderate reactivity in 25 (14.9%) and weak reactivity in 10 (6.0%) cases. Strong/moderate immunoreactivities were mostly observed in invasive fronts of the tumors or in both invasive and other areas. Fascin immunoreactivity scores were significantly higher in tumors with lymph node metastasis (p:0.002) and advanced stage presentation (p:0.007). There was no relation between fascin expression and age, gender, depth of invasion, distant metastasis or histological grade (p>0.05). There was a higher and statistically significant correlation between fascin immunoreactivity in the invasive borders of tumors and lymph node metastasis (r:0.747, p:0.005). In stage III/IV tumors, two-year survival was 92.2% in tumors without fascin immunoreactivity, and only 60.0% in tumors with a fascin IHS>10 (p:0.003).

CONCLUSION

These findings suggest that fascin is heterogeneously expressed in approximately one third of colorectal carcinomas with a significant association with lymph node metastasis, tumor stage and location. Moreover, these results indicate that fascin may have a role in the lymph node metastasis of colorectal carcinomas.

Fascin expression in progression and prognosis of hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

Fascin is an actin-bundling protein and induces membrane protrusions and cell motility after the formation of lamellipodia or filopodia. Fascin expression has been reported to be associated with progression or prognosis in various neoplasms, but the role of fascin in hepatocellular carcinoma (HCC) remains unknown. The aim of this study was to investigate the clinicopathological and prognostic relevance of fascin by immunohistochemistry.

METHODS

A total of 137 patients with HCC were stained with anti-fascin antibody. The tumor cells having unequivocal cytoplasmic and/or membranous fascin immunoreactivity were defined as fascin-positive.

RESULTS

Immunohistochemically, 23 (16.8%) HCCs having unequivocal fascin immunoreactivity were found. Tumors showing fascin expression were larger and less differentiated than those showing no fascin expression (P = 0.0239 and 0.0018, respectively). Portal venous invasion, bile duct invasion, and intrahepatic metastasis were detected significantly more frequently in fascin-positive group (P = 0.0029, 0.0333, and 0.0403, respectively). In addition, high alpha-fetoprotein (AFP) levels were significantly associated with the fascin expression in HCC (P = 0.0116). Fascin-positive group had significantly poorer outcomes than fascin-negative group and was an independent prognostic factor for disease-free survival.

CONCLUSIONS

Fascin might become a novel marker of progression in HCC and a significant indicator of a poor prognosis for patients with HCC.

TGF-beta promotes invasion and metastasis of gastric cancer cells by increasing fascin1 expression via ERK and JNK signal pathways

Transforming growth factor-beta (TGF-beta) is involved in actin cytoskeleton reorganization and tumor progression. Fascin1, an actin-binding protein, increases cell invasiveness and motility in various transformed cells. To determine whether fascin1 is an important mediator of the tumor response to TGF-beta, we applied the small interfering RNA (siRNA) technique to silence fascin1 in gastric cancer (GC) cells MKN45. Results showed that the effects of TGF-beta1 on GC cells invasion and metastasis were mediated by tumor production of fascin1; furthermore, it was found that TGF-beta1- induced fascin1 expression was suppressed by the specific inhibitors of JNK and ERK pathways, SP6001125 and PD98059, respectively, but not by transient transfection of Smad2 and Smad4 siRNA. Our data for the first time demonstrated that fascin1 is an important mediator of TGF-beta1-induced invasion and metastasis of GC cells, which involves JNK and ERK signaling pathways.

The expression of six biomarkers in the four most common ovarian cancers: correlation with clinicopathological parameters

This study aimed to evaluate the relationship of fascin-1, matrix metalloproteinase (MMP)-2, MMP-9, cortactin, survivin, and epidermal growth factor receptor (EGFR) expression with clinicopathological parameters for the four most common ovarian surface epithelial carcinomas. Six biomarkers were investigated immunohistochemically using tissue microarrays of 185 specimens including 79 serous cystadenocarcinomas, 47 mucinous cystadenocarcinomas, 45 endometrioid adenocarcinomas, and 14 clear cell carcinomas. The four most common ovarian carcinomas showed significant expression of fascin-1, cortactin, survivin, and EGFR, but not of MMP-2 and MMP-9. In addition, higher immunostaining scores for fascin-1 in mucinous cystadenocarcinomas correlated with T stage, N stage, American Joint Committee on Cancer AJCC clinical stage, and a poorer survival rate; for cortactin in serous cystadenocarcinomas correlated with T stage; for cortactin in clear cell carcinomas correlated with T and clinical AJCC stages; and for survivin in clear cell carcinomas correlated with T stage and AJCC clinical stage. In addition, higher immunostaining scores for fascin-1, cortactin, and survivin correlated with poorer tumor differentiation in serous, mucinous, and endometrioid adenocarcinomas. Thus, the expression of fascin-1, cortactin, and survivin may be helpful in evaluating the aggressiveness of ovarian mucinous, serous, and clear cell adenocarcinoma. Additionally, the expression of fascin-1 may be an independent prognostic risk factor in mucinous cystadenocarcinoma.