MicroRNAs (miRNAs), noncoding RNAs 21-25 nucleotides in length, regulate gene expression primarily at the posttranscriptional level. Growing evidence suggests that miRNAs are aberrantly expressed in many human cancers, and that they play significant roles in carcinogenesis and cancer progression. A search for miRNAs with a tumor-suppressive function in esophageal squamous cell carcinoma (ESCC) was performed using the miRNA expression signatures obtained from ESCC clinical specimens. A subset of 15 miRNAs was significantly downregulated in ESCC. A comparison of miRNA signatures from ESCC and our previous report identified 4 miRNAs that are downregulated in common (miR-145, miR-30a-3p, miR-133a and miR-133b), suggesting that these miRNAs are candidate tumor suppressors. Gain-of-function analysis revealed that 3 transfectants (miR-145, miR-133a and miR-133b) inhibit cell proliferation and cell invasion in ESCC cells. These miRNAs (miR-145, miR-133a and miR-133b), which have conserved sequences in the 3 0 UTR of FSCN1 (actin-binding protein, Fascin homolog 1), inhibited FSCN1 expression. The signal from a luciferase reporter assay was significantly decreased at 2 miR-145 target sites and 1 miR-133a/b site, suggesting both miRNAs directly regulate FSCN1. An FSCN1 loss-of-function assay found significant cell growth and invasion inhibition, implying an FSCN1 is associated with ESCC carcinogenesis. The identification of tumor-suppressive miRNAs, miR-145, miR-133a and miR-133b, directly control oncogenic FSCN1 gene. These signal pathways of ESCC could provide new insights into potential mechanisms of ESCC carcinogenesis.Human esophageal cancer occurs worldwide with a variable geographic distribution. The disease ranks eighth in order of occurrence and sixth as the leading cause of cancer mortality, affecting men more than women. 1 There are 2 main forms, each with distinct etiologic and pathologic characteristics: esophageal squamous cell carcinoma (ESCC) and adenocarcinoma. ESCC is the most frequent subtype of esophageal cancer, although the incidence of adenocarcinoma in the western world is increasing faster than other malignancies. ESCC is one of the most aggressive and lethal malignancies in eastern Asia. Because most cases of ESCC are not diagnosed until the disease is at an advanced stage, the overall 5-year survival rate is very poor.2-4 Recently, the combination of chemotherapy and radiotherapy, alone or as an adjunct to surgery, has improved the prognosis of ESCC patients. 5,6 Research over the last 20 years has identified a number of oncogenic and tumor-suppressor proteins that are associated with the induction of ESCC. 7,8 However, molecular indicators of the origin of cellular deregulation in ESCC have not been identified. Elucidation of the molecular pathways involved in ESCC carcinogenesis could lead to improvements in disease diagnosis and therapy.MicroRNAs (miRNAs) are a class of naturally occurring small (21-25 nucleotides) noncoding RNAs. Mature miRNAs play important regulatory roles in cell growth, p...

Background:Recent studies have demonstrated that microRNAs (miRNAs) are stably detectable in blood and can serve as useful biomarkers for cancer.Methods:We performed an miRNA array using serum samples obtained from oesophageal squamous cell carcinoma (ESCC) patients or healthy controls. MiR-1246 was the most markedly elevated in ESCC patients. Therefore, miR-1246 was selected as a candidate for further analysis. The serum miR-1246 level in 46 healthy controls and 101 ESCC patients was evaluated and compared among various clinicopathological characteristics. MiR-1246 expressions in tissue, exosomal, and cellular samples were also examined.Results:Serum miR-1246 alone yielded an receiver-operating characteristic curve area of 0.754, with 71.3% sensitivity and 73.9% specificity for distinguishing ESCC patients from healthy controls. Serum miR-1246 was significantly correlated with the TNM stage and showed to be the strongest independent risk factor for poor survival (HR, 4.032; P=0.017). Unlike the tendency shown in previous reports, miR-1246 was not upregulated in ESCC tissue samples. Furthermore, exosomal miR-1246 did not reflect the abundance in the cell of origin.Conclusion:These data support our contention that serum miR-1246 has strong potential as a novel diagnostic and prognostic biomarker in ESCC, and its releasing mechanism is selective and independent of tissue miRNA abundance.

SummaryKeratin filaments form cytoskeletal networks in epithelial cells. Dynamic rearrangement of keratin filament networks is required for epithelial cells to perform cellular processes such as cell migration and polarization; however, the mechanism governing keratin filament rearrangement remains unclear. Here, we describe a novel mechanism of keratin cytoskeleton organization mediated by casein kinase Ia (CK-1a) and a newly identified keratin-associated protein, FAM83H. Knockdown of FAM83H induces keratin filament bundling, whereas overexpression of FAM83H disassembles keratin filaments, suggesting that FAM83H regulates the filamentous state of keratins. Intriguingly, keratin filament bundling is concomitant with the dissociation of CK-1a from keratin filaments, whereas aberrant speckle-like localization of CK-1a is observed concomitantly with keratin filament disassembly. Furthermore, CK-1a inhibition, similar to FAM83H knockdown, causes keratin filament bundling and reverses keratin filament disassembly induced by FAM83H overexpression, suggesting that CK-1a mediates FAM83H-dependent reorganization of keratin filaments. Because the N-terminal region of FAM83H interacts with CK-1a and the C-terminal region interacts with keratins, FAM83H might tether CK-1a to keratins. Colorectal cancer tissue also shows keratin filament disassembly accompanied with FAM83H overexpression and aberrant CK-1a localization, and FAM83H-overexpressing cancer cells exhibit loss or alteration of epithelial cell polarity. Importantly, knockdown of FAM83H inhibits cell migration accompanied by keratin cytoskeleton rearrangement in colorectal cancer cells. These results suggest that keratin cytoskeleton organization is regulated by FAM83H-mediated recruitment of CK-1a to keratins, and that keratin filament disassembly caused by overexpression of FAM83H and aberrant localization of CK-1a could contribute to the progression of colorectal cancer.

Our study provides a precise assessment of the comprehensive risk of metastasis and feasible predictive markers for T1 ESCC.

Background:FSCN1 and matrix metalloproteinase 14 (MMP14) are both invadopodia-related proteins. We herein elucidate the tumourigenicity of these proteins and identify novel therapeutic agents in esophageal squamous cell carcinoma (ESCC).Methods:FSCN1 and MMP14 were evaluated by immunohistochemistry and quantitative PCR, and microRNA (miR)-133a was also evaluated by PCR in surgical ESCC specimens. The roles of FSCN1, MMP14 and miR-133a were established in ESCC cells.Results:The expression of FSCN1 or MMP14 was an independent poor prognostic factor according to a multivariate analysis of immunohistochemistry, and their co-expression correlated with the poorest overall survival (OS) out of all the examined factors. Additionally, their mRNAs significantly correlated and both inversely correlated with miR-133a in surgical specimens. Transfection of a miR-133a mimic decreased the mRNA and protein levels of both FSCN1 and MMP14 in ESCC cells. The knockdown of FSCN1 or MMP14 and transfection of a miR-133a mimic inhibited the proliferation and invasion of ESCC cells. Patients with a lower miR-133a expression have a significantly poorer OS than those with a higher expression.Conclusion:The combined expression of FSCN1 and MMP14 is associated with a poor prognosis, and miR-133a, which regulates their mRNAs, can serve as a strong tumour suppressor of ESCC.