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Background MicroRNAs (miRNAs) are small non-coding RNAs that silence their cognate target genes by specifically binding and cleaving messenger RNAs or inhibiting their translation. In this study, we explored whether miRNA-141 and miRNA-200b are involved in regulation of the invasive ability and epithelial–mesenchymal transition (EMT) of bladder cancer cells in vitro. We also evaluated their potential as biomarkers for deciding the extent of pelvic lymph node dissection (PLND) required during radical cystectomy. Methods Pri- and anti-miR cell lines were constructed. The invasive capacity of the cells was tested using a cell invasion assay. The MMP-2, MMP-9 and EMT-related markers were validated through Western blotting analysis. Seventy-eight urine samples from patients undergoing cystectomy and super-extended lymph node dissection were evaluated by qRT-PCR. Results Loss of expression of miRNA-141 and miRNA-200b was associated with increased invasion and migration ability, upregulated MMP-2, MMP-9, vimentin and N-cadherin expression, and downregulated E-cadherin expression in bladder cancer cell lines. Urine miRNA-141 and miRNA-200b levels could discriminate patients with lymph node metastasis from those who were lymph node negative (AUC: 0.704 and 0.674, respectively). Conclusion MiRNA-141 and miRNA-200b play important roles in the invasive ability and EMT phenotype of bladder cancer. Detection of miRNA-141 and miRNA-200b can help to identify patients undergoing cystectomy who are likely to have lymph node metastasis, and therefore those who may benefit from super-extended PLND. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1110-7) contains supplementary material, which is available to authorized users.

Background Cytoplasmic linker-associated protein 2 (CLASP2) belongs to a family of microtubule plus-end tracking proteins that localizes to the distal ends of microtubules and regulate microtubule dynamics. We speculated that it might be involved in the epithelial-mesenchymal transition (EMT) and progression of bladder cancer (BC). Methods Western blotting and RT-PCR were used to detect the changes at protein and mRNA levels in BC cell lines. Cell proliferation, clonogenic formation, wound healing and chamber invasion assay were used to investigate the abilities of cellular proliferation, migration and invasion. The data of BC patients treated with transurethral resection of the bladder tumor (TURBT) was collected and analyzed. The levels of mRNA of CLASP2 and EMT-related markers in tumor and urine samples were tested by RT-PCR. Results Expressions of CLASP2 varied in four BC cell lines. Manipulation of CLASP2 expression changed EMT-related markers. CLASP2 could promote proliferation, migration and invasion in BC cell lines. The combination (CLASP2 + E-cadherin mRNA in urine) could better discriminate the patients with or without 2-years progression compared with tumor grade after TURBT. Conclusion CLASP2 is involved in the EMT and progression of bladder urothelial cancer. Simultaneous urine-based detection of CLASP2 and E-cadherin mRNA can efficiently discriminate patients with or without 2-years progression after TURBT.