miR-145, miR-133a and miR-133b: Tumor-suppressive miRNAs target FSCN1 in esophageal squamous cell carcinoma.

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'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.

Kano M ，Seki N ，Kikkawa N ，Fujimura L ，Hoshino I ，Akutsu Y ，Chiyomaru T ，Enokida H ，Nakagawa M ，Matsubara H ... -  《-》

Restoration of miR-145 expression suppresses cell proliferation, migration and invasion in prostate cancer by targeting FSCN1.

Fuse M ，Nohata N ，Kojima S ，Sakamoto S ，Chiyomaru T ，Kawakami K ，Enokida H ，Nakagawa M ，Naya Y ，Ichikawa T ，Seki N ... -  《-》

miR-145 and miR-133a function as tumour suppressors and directly regulate FSCN1 expression in bladder cancer.

Chiyomaru T ，Enokida H ，Tatarano S ，Kawahara K ，Uchida Y ，Nishiyama K ，Fujimura L ，Kikkawa N ，Seki N ，Nakagawa M ... -  《-》

Functional role of LASP1 in cell viability and its regulation by microRNAs in bladder cancer.

Our previous study demonstrated that fascin homolog 1 (FSCN1) might have an oncogenic function in bladder cancer (BC) and that its expression was regulated by specific microRNAs (miRNAs). Recently, LIM and SH3 protein 1 (LASP1) as well as FSCN1 have been reported as actin filament bundling proteins in the same complexes attached to the inner surfaces of cell membranes. We hypothesize that LASP1 as well as FSCN1 have an oncogenic function and that is regulated by miRNAs targeting LASP1 mRNA. The expression levels of LASP1 mRNA in 86 clinical samples were evaluated by real-time RT-PCR. LASP1-knockdown BC cell lines were transfected by siRNA in order to examine cellular viability by XTT assay, wound healing assay, and matrigel invasion assay. We employed web-based software in order to search for candidate miRNAs targeting LASP1 mRNA, and we focused on miR-1, miR-133a, miR-145, and miR-218. The luciferase reporter assay was used to confirm the actual binding sites between the miRNAs and LASP1 mRNA. Real-time RT-PCR showed that LASP1 mRNA expression was higher in 76 clinical BC specimens than in 10 normal bladder epitheliums (P < 0.05). Loss-of-function studies using si-LASP1-transfected BC cell lines demonstrated significant cell viability inhibition (P < 0.0005), cell migration inhibition (P < 0.0001), and a decrease in the number of invading cells (P < 0.005) in the transfectants compared with the controls. Transient transfection of three miRNAs (miR-1, miR-133a, and miR-218), which were predicted as the miRNAs targeting LASP1 mRNA, repressed the expression levels of mRNA and protein levels of LASP1. The luciferase reporter assay demonstrated that the luminescence intensity was significantly decreased in miR-1, miR-133a, and miR-218 transfectants (P < 0.05), suggesting that these miRNAs have actual target sites in the 3' untranslated region of LASP1 mRNA. Furthermore, significant cell viability inhibitions occurred in miR-218, miR-1, and miR-133a transfectants (P < 0.001). Our data indicate that LASP1 may have an oncogenic function and that it might be regulated by miR-1, miR-133a, and miR-218, which may function as tumor suppressive miRNAs in BC.

Chiyomaru T ，Enokida H ，Kawakami K ，Tatarano S ，Uchida Y ，Kawahara K ，Nishiyama K ，Seki N ，Nakagawa M ... -  《-》

Downregulation of miR-138 sustains NF-κB activation and promotes lipid raft formation in esophageal squamous cell carcinoma.

Constitutive activation of NF-κB signaling plays vital roles in esophageal squamous cell carcinoma (ESCC) progression. The aim of this study was to evaluate the effect of miR-138 on NF-κB activation and ESCC progression. Expression of miR-138 in ESCC cell lines, ESCC tissues, and 205 archived ESSC specimens was determined using real-time PCR analysis. Anchorage-independent growth, chicken chorioallantoic membrane, Transwell matrix invasion and Annexin V-binding assays, and a xenograft tumor model were used to determine the role of miR-138 in ESCC progression. The effect of miR-138 on NF-κB activation was investigated using IKK in vitro kinase, electrophoretic mobility shift, lipid raft isolation, and luciferase reporter assays. miR-138 was downregulated and inversely correlated with tumor progression and patient survival in ESCCs. Downregulation of miR-138 enhanced, whereas upregulation of miR-138 reduced, the aggressive phenotype of ESCC cells both in vitro and in vivo. Silencing miR-138 promoted K63-linked polyubiquitination of the NF-κB signaling intermediaries TRAF2 and RIP1 and sustained NF-κB activation. Furthermore, downregulation of miR-138 induced lipid raft formation via upregulating multiple components of lipid rafts, including FLOT1, FLOT2, and caveolin-1. Importantly, the in vitro analysis was consistent with a significant inverse correlation between miR-138 expression and NF-κB hyperactivation in a cohort of human ESCC specimens. Our results show that miR-138 functions as a tumor-suppressive miRNA and that downregulation of miR-138 contributes to constitutive NF-κB activation and ESCC progression.

Gong H ，Song L ，Lin C ，Liu A ，Lin X ，Wu J ，Li M ，Li J ... -  《-》