Genomic Profiling of MicroRNAs in Bladder Cancer: miR-129 Is Associated with Poor Outcome and Promotes Cell Death In vitro

Abstract

microRNAs (miRNA) are involved in cancer development and progression, acting as tumor suppressors or oncogenes. Here, we profiled the expression of 290 unique human miRNAs in 11 normal and 106 bladder tumor samples using spotted locked nucleic acid-based oligonucleotide microarrays. We identified several differentially expressed miRNAs between normal urothelium and cancer and between the different disease stages. miR-145 was found to be the most down-regulated in cancer compared with normal, and miR-21 was the most upregulated in cancer. Furthermore, we identified miRNAs that significantly correlated to the presence of concomitant carcinoma in situ. We identified several miRNAs with prognostic potential for predicting disease progression (e.g., miR-129, miR-133b, and miR-518c*). We localized the expression of miR-145, miR-21, and miR-129 to urothelium by in situ hybridization. We then focused on miR-129 that exerted significant growth inhibition and induced cell death upon transfection with a miR-129 precursor in bladder carcinoma cell lines T24 and SW780 cells. Microarray analysis of T24 cells after transfection showed significant miR-129 target downregulation (P = 0.0002) and pathway analysis indicated that targets were involved in cell death processes. By analyzing gene expression data from clinical tumor samples, we identified significant expression changes of target mRNA molecules related to the miRNA expression. Using luciferase assays, we documented a direct link between miR-129 and the two putative targets GALNT1 and SOX4. The findings reported here indicate that several miRNAs are differentially regulated in bladder cancer and may form a basis for clinical development of new biomarkers for bladder cancer. [Cancer Res 2009;69(11):4851-60]

The MicroRNA Profile of Prostate Carcinoma Obtained by Deep Sequencing

“…This phenomenon has been noticed in several occasions. Although it has been shown that miR-200c is consistently upregulated in prostate cancer (20), the opposite has been reported for bladder cancer (27). We conclude that the role of an individual miRNA in tumor initiation or growth is organ or cell type specific so that differences in its deregulation between different tumor entities are not a contradiction, but rather reflect different roles of its target gene or genes in different tumor types.…”

miR-145 induces caspase-dependent and -independent cell death in urothelial cancer cell lines with targeting of an expression signature present in Ta bladder tumors

“…The downregulation of miR-145 ( Figure 1a) in bladder cancer specimens and urothelial cell lines, as compared with normal biopsies (Figures 1b and c) (Dyrskjot et al, 2009), prompted us to investigate whether the differences in miRNA levels measured may reflect tissue heterogeneity and/or an altered ratio of different cell types to the tumor mass, rather than tumor cell-specific expression changes. We performed ISH analysis to identify which cell type(s) expressed miR-145 (Figure 2).…”

“…In accordance, miRNAs have been shown to influence gene regulatory processes in, for example, development, differentiation, and disease, such as cancer (Calin and Croce, 2006;Esquela-Kerscher and Slack, 2006), in which specific miRNA signatures have been associated with different clinical outcomes (Nakajima et al, 2006;Rajewsky, 2006;Yanaihara et al, 2006;Sempere et al, 2007;Tavazoie et al, 2008;Dyrskjot et al, 2009). Approximately 50% of the known miRNAs are located within regions of genomic instability that are amplified or deleted in cancer (Calin et al, 2004), which may in part explain the aberrant expression observed.…”

“…We recently identified miR-145 as the most significantly downregulated miRNA (P ¼ 2.1EÀ08) in an miRNA profiling study on bladder cancer comprising 106 clinical samples of bladder cancer and 11 normal bladder biopsies (Dyrskjot et al, 2009). Bladder cancer is the fourth most common cancer among men and can be pathologically classified into discrete stages; Ta are benign papillary tumors, T1 are lamina propriainvasive tumors, carcinoma in situ (CIS) are small in situ lesions of high-grade atypia, and T2-T4 are muscleinvasive tumors.…”

MiR-129-5p is down-regulated and involved in migration and invasion of gastric cancer cells by targeting interleukin-8

“…MiR-129-5p, one of the mature forms of miR-129-1 and miR-129-2, has been reported to be involved in various neoplastic processes, including GC [7][8][9]. It has been demonstrated that miR-129-5p serves as an important tumor suppressor, and overexpression of miR-129-5p could significantly decrease the cell proliferation activity of multiple tumor cell lines, such as endometrial tumor cells, lung adenocarcinoma cell lines, bladder cancer cells, and GC cells [7,[10][11][12]. Another mature form of miR-129-1 and miR-129-2, miR-129-3p, has been suggested as a diagnostic and prognostic biomarker for renal cell carcinoma (RCC), and could regulate cell migration and invasion by downregulating multiple metastasis-related genes [13].…”