MiR-15 suppressed the progression of bladder cancer by targeting BMI1 oncogene via PI3K/AKT signaling pathway.OBJECTIVE
 To investigate the role of microRNA-15 (miR-15) in the progression of bladder cancer (BC) cell and its underlying mechanism.


 Furthermore, the luciferase reporter assay was used to verify the target gene of miR-15.  Besides, Xenograft tumor formation assay was performed to confirm the effect of miR-15 on tumor growth.


 A low expression of miR-15 was detected by qRT-PCR, whereas the high expression of B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) was detected by immunocytochemical assay in BC tissues.  Moreover, miR-15 expression and BMI1 expression were significantly associated with the overall survival of BC patients.  MTT and transwell assay results stated that the up-regulation of miR-15 inhibited BC cell proliferation, migration, and invasion.  BMI-1 was verified as a direct target of miR-15 in BC using Luciferase reporter assay.  Besides, miR-15 regulated epithelial-mesenchymal transition (EMT)-related makers, protein kinase B (AKT), and the phosphorylation of AKT protein levels in BC using the Western blot assay.  Xenograft tumor formation assay indicated that the over-expression of miR-15 inhibited the tumor growth.


 We stated that miR-15 suppressed BC cell progression by targeting BMI1 through the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, which provided a potential target for BC treatment.
MiR-15
MiR-15 suppressed the progression of bladder cancer by targeting BMI1 oncogene via PI3K/AKT signaling pathway.OBJECTIVE
 A low expression of miR-15 was detected by qRT-PCR, whereas the high expression of B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) was detected by immunocytochemical assay in BC tissues.  Moreover, miR-15 expression and BMI1 expression were significantly associated with the overall survival of BC patients.  We stated that miR-15 suppressed BC cell progression by targeting BMI1 through the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, which provided a potential target for BC treatment.
BMI1
MiR-15 suppressed the progression of bladder cancer by targeting BMI1 oncogene via PI3K/AKT signaling pathway.OBJECTIVE

PI3K/AKT signaling pathway
The abilities of cell proliferation and invasion were detected by Methyl thiazolyl tetrazolium (MTT) and transwell assay, respectively. 
Methyl thiazolyl tetrazolium (MTT)
The abilities of cell proliferation and invasion were detected by Methyl thiazolyl tetrazolium (MTT) and transwell assay, respectively.  MTT and transwell assay results stated that the up-regulation of miR-15 inhibited BC cell proliferation, migration, and invasion. 
transwell assay
Additionally, the relevant mRNA and protein expressions were measured by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blot and immunohistochemistry, respectively.  A low expression of miR-15 was detected by qRT-PCR, whereas the high expression of B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) was detected by immunocytochemical assay in BC tissues. 
qRT-PCR
Additionally, the relevant mRNA and protein expressions were measured by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blot and immunohistochemistry, respectively.  Besides, miR-15 regulated epithelial-mesenchymal transition (EMT)-related makers, protein kinase B (AKT), and the phosphorylation of AKT protein levels in BC using the Western blot assay. 
Western blot
Additionally, the relevant mRNA and protein expressions were measured by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blot and immunohistochemistry, respectively. 
immunohistochemistry
Furthermore, the luciferase reporter assay was used to verify the target gene of miR-15.  BMI-1 was verified as a direct target of miR-15 in BC using Luciferase reporter assay. 
luciferase reporter assay
Besides, Xenograft tumor formation assay was performed to confirm the effect of miR-15 on tumor growth.


 Xenograft tumor formation assay indicated that the over-expression of miR-15 inhibited the tumor growth.



Xenograft tumor formation assay