Table 3 Summary of possible role and potential mechanism of miRs entered this study in bladder cancer.

From: MicroRNAs with prognostic significance in bladder cancer: a systematic review and meta-analysis

microRNA

Role

Mechanism

Reference

miR-155

Proto-oncogene

Zhang: miR-155 overexpression promotes some tumor cell growth via Wnt/β-catenin signaling activation which is also a vital pathway in bladder cancer tumorigenesis.

14, 19

  

Wang: Oncogenic properties of miR-155 are attributed to its antiapoptotic function through a blockade of caspase-3 activity or suppression of proapoptotic genes such as TP53BP1 and promote cell proliferation by down-regulating the SOCS1 gene, or activate PKB signaling via downregulation of tumor suppressors, including PTEN, PDCD4, and SHIP1.

 

miR-203

Tumor suppressor

miR-203 simultaneously suppressed antiapoptotic factors Bcl-w and Survivin.

15

miR-21

Proto-oncogene

Zhang: miR-21 functions through regulation of maspin and VEGF-C, suggesting a miR-21/maspin/VEGF-C pathway in bladder cancer.

16, 25

  

Zaravinos: miR-21 represses the tumor suppressors PTEN deleted on chromosome 10, tropomyosin 1 and the PDCD4.

 

miR-424

Tumor suppressor

miR-424 regulates multiple cellular biological behaviors, such as retarding growth, inducing apoptosis, and reducing invasion, by directly targeting EGFR in bladder cancer.

36

miR-214

Tumor suppressor

Wang: miR-214 could exert tumor-suppressive effects in bladder cancer by directly down-regulating oncogene PDRG1.

17, 24

  

Kim: miR-214 could be related to the inhibition of angiogenesis, to cell proliferation, and to tumor recurrence.

 

miR-152

Proto-oncogene

miR-152 acts through upregulation of DNA hypermethylation in bladder cancer.

30

miR-27a-3p

Tumor suppressor

miR-27a-3p as a target of mutant p53–273 H and uncovered a novel mutant p53–273 H/miR-27a-3p/EGFR pathway which played an important role in tumorigenesis.

30

miR-143

Tumor suppressor

miR-143 can suppress cell proliferation and migration as well as promote apoptosis in bladder cancer by inhibiting PI3K/Akt and MAPK signaling.

21

miR-224

Proto-oncogene

The upregulation of miR-224 levels has been observed to promote cell migration and tumor growth by targeting the tumor suppressors.

21

miR-34a

Tumor suppressor

miR-34a expression can inhibit cell migration and invasion by antagonizing Notch1 signaling.

39

miR-101

Tumor suppressor

Abnormal down-regulation of miR-101 could frequently lead to the overexpression of EZH2 in cancer, which increased cell proliferation in bladder cancer cells and retarded transition of G phase to S phase.

34

miR-222

Proto-oncogene

miR-222 decreased the tumor suppressor PTEN, which was considered to enhance angiogenesis, tumor cell proliferation, EMT and activation of metastasis in bladder cancer.

67

miR-26a

Tumor suppressor

miR-26a functions through regulation of HMGA1 in bladder cancer.

35

miR-29c

Tumor suppressor

miR-29c regulates the apoptotic protein MCL1 and thereby regulating apoptosis as well as DNA de novo methyltransferases DNMT3A and DNMT3B, key enzymes that are frequently up-regulated in cancer.

29

miR-210

Proto-oncogene

miR-210 over expression activates VEGF and leads to the formation of capillary structures under hypoxic conditions during the early steps of tumor development.

25

miR-200

Tumor suppressor

Higher levels of miR-200 might inhibit EMT and prevent non-muscle invasive bladder cancer recurrence through the silencing of various target genes.

26

miR-27a

Tumor suppressor

miR-27a functions through regulation of cystine/glutamate exchanger SLC7A11 in bladder cancer.

38

miR-129

Proto-oncogene

miR-129 simultaneously repressed the tumor suppressors SOX4 and GALNT1 in bladder cancer.

29

miR-29c*

Tumor suppressor

miR-29c* acts through downregulation of DNA methyltransferases as well as upregulation of demethylating genes to keep the normal methylation pattern.

37

miR-9

Proto-oncogene

miR-9 directly targeted the CDH-1 gene encoding E-cadherin, a regulator of EMT, considered to be an important initiating step for tumor metastasis.

23

  1. TP53BP1: tumor protein p53 binding protein 1; SOCS1: suppressor of cytokine signaling 1; PKB: protein kinase B; PTEN: phosphatase and tensin homolog; PDCD4: programmed cell death 4; VEGF-C: vascular endothelial growth factor-C; EGFR: epidermal growth factor receptor; PDRG1: p53 and DNA-damage regulated 1; EZH2: enhancer of zeste homologue 2; HMGA1: high mobility group AT-hook 1; MCL1: myeloid cell leukemia 1; DNMT3A: DNA-methyltransferase 3 alpha; DNMT3B: DNA-methyltransferase 3 beta; EMT: epithelial-to-mesenchymal transition; SLC7A11: solute carrier family 7 member 11; SOX4: SRY-box 4; GALNT1: polypeptide N-acetylgalactosaminyltransferase 1; CDH1: cadherin 1.