Hypoxia Promotes Invasion And Metastasis Of Hypopharyngeal Squamous Cell Carcinoma Through An HIF-1?-fascin-1 Loop

Part ?Fascin-1 promotes invasion and metastasis of hypopharyngeal squamous cell carcinomaObjective:Fascin-1 is an actin-bundling protein,which specifically interacts with F-actin to form parallel actin bundles and participates in the regulation of cell adhesion,interactions and migration.However,the expression of fascin-1 in HSCC and the regulatory mechanism of fascin-1 in HSCC are still poorly understood.In the present study,we investigated the effects of fascin-1 on invasion and metastasis of HSCC,and further explored the underlying molecular mechanism of fascin-1 promoting invasion and metastasis of HSCC.Methods:To validate fascin-1 expression levels in HSCC and further analyze the relationships between fascin-1 expression and clinicopathological characteristics and prognosis,immunohistochemistry were used in a cohort of 96 patients with HSCCs.To identify the effects of fascin-1 in FaDu cells,fascin-1 knockdown and over-expression was used.Western blot analysis was used to determine the transfection efficiency of fascin-1 siRNA and expression plasmids in FaDu cells.The fluorescently labeled phalloidin staining of F-actin was performed to observe alterations in cell morphology.Wound-healing and Transwell assays were performed to further determine the effects of fascin-1 on cell migration and invasion.The expression of proteins associated with invasion,metastasis and epithelial-mesenchymal transition,including MMP-2,MMP-9,E-cadherin and vimentin were examined by western blotting to determine whether fascin-1 influenced cell invasion and migration at the molecular level.Results:Our results showed that fascin-1 is overexpressed and correlated with lymph node metastasis and tumor-node-metastasis(TNM)stage in HSCC tissues,but fascin-1 expression was not associated with 3-year survival.Further study revealed that fascin-1 promoted cell morphology polarized to increase the motility ability of FaDu cells and fascin-1 significantly promoted migration and invasion of FaDu cells in wound-healing assay and Transwell assays.At the molecular level,fascin-1 promoted cell invasion and metastasis by up-regulating matrix metalloproteinase-2(MMP-2)expression in FaDu cells.Conclusions:Fascin-1 involved in invasion and metastasis of HSCC and may play a vital role in invasion and metastasis of HSCC.Fascin-1 led to cell morphological changes and increased the migration and invasion ability of FaDu cells.Fascin-1 promoted the invasion of FaDu cells through up-regulating the expression of MMP-2.Part ?Hypoxia promotes invasion and metastasis of hypopharyngeal squamous cell carcinoma through an HIF-1?-fascin-1 positive feedback loopObjective:Hypoxia is one of the most common microenvironment stresses in solid tumors,which plays key roles in tumor invasion and metastasis.HIF-la is a key regulator of the cellular response to hypoxia and controls the expression of target genes associated with tumor invasion and metastasis.Fascin-1 is a globular actin cross-linking protein,which is found to be associated with tumor cell invasion and metastasis in various types of cancers.A previous study reported that fascin expression is colocalized with HIF-1? and is significantly correlated with HIF-1?expression in pancreatic ductal adenocarcinoma tissues.Thereby,in the present study,we have mainly investigated the colocalization and the correlation between fascin-1 and HIF-1? expression in consecutive sections of HSCC tissues,and further explored the underlying mechanism of fascin-1 involved in invasion and metastasis of HSCC under hypoxia.Methods:To investigated the colocalization and the correlation between fascin-1 and HIF-1? expression in consecutive sections of HSCC tissues,immunohistochemistry were used in consecutive sections of HSCC tissues.To mimic hypoxia microenvironment,the hypoxia model was established by Cobalt chloride(CoCl2)treatment.To understand the role of hypoxia in invasion and metastasis of HSCC,wound-healing assay,Transwell assays and western blotting assay were performed.HIF-1? knockdown was used to identify HIF-1? involved in invasion and metastasis of HSCC under hypoxia and fascin-1 knockdown was used to identify fascin-1 involved in invasion and metastasis of HSCC under hypoxia.Furthermore,the overexpression or knockdown of HIF-1? and fascin-1 were used to explore the relationship between HIF-1? and fascin-1 through Western blotting assayResults:Immunohistochemical results showed that fascin-1 expression co-localized with HIF-la expression in consecutive sections of HSCC tissues,and the correlation between fascin-1 and HIF-1? expression was significant in HSCC tissues.Hypoxia induced by CoCl2 in HSCC led to significant increase in cell migration,invasion and MMP-2 activity.In addition,hypoxia induced by CoCl2 in HSCC up-regulated the expression of HIF-1? and fascin-1 and hypoxia promoted invasion and metastasis of HSCC through HIF-1? and fascin-1.our results also revealed that there is positive mutual regulation between HIF-1? and fascin-1 in HSCC.Conclusions:our results indicated that fascin-1 expression was significantly correlated with HIF-1? and HIF-1? may be involved in fascin-1 overexpression in HSCC tissues.Furthermore,there is positive mutual regulation between HIF-1? and fascin-1 in HSCC and hypoxia promotes invasion and metastasis of HSCC through an HIF-1?-fascin-1 positive feedback loop.The HIF-1?-fascin-1 loop may provide a potentially target for the therapy of invasion and metastasis in HSCC.