MiR-126 regulates proliferation and invasion in the bladder cancer BLS cell line by targeting the <em>PIK3R2</em>-mediated PI3K/Akt signaling pathway

Abstract

ObjectiveTo assess whether microRNA-126 (miR-126) targets phosphatidylinositol 3-kinase regulatory subunit beta (PIK3R2) and to determine the potential roles of miR-126 in regulating proliferation and invasion via the PIK3R2-mediated phosphatidylinositol 3 kinase (PI3K)-protein kinase B (Akt) signaling pathway in the human bladder BLS cell line.Materials and methodsA recombinant lentivirus (Lv) vector expressing miR-216 (Lv-miR-126) was successfully constructed, and Lv-miR-126 and Lv vector were transfected into the BLS cell line. A direct regulatory relationship between miR-126 and the PIK3R2 gene was demonstrated by luciferase reporter assays. To determine whether PIK3R2 directly participates in the miR-126-induced effects in BLS cells, anti-miR-126 and a PIK3R2 small interfering RNA (siRNA) were transfected into the BLS cells. Quantitative real-time polymerase chain reaction was used to measure miR-126 and PIK3R2 expressions. 5-Ethynyl-2′-deoxyuridine and colony formation assays to assess cell proliferation, flow cytometry for cell apoptosis and cell cycle analysis, Transwell assays for cell migration and invasion, and Western blots for PIK3R2, PI3K, phosphorylated PI3K (p-PI3K), Akt, and phosphorylated Akt (p-Akt) protein expressions were performed.ResultsLv-miR-126 significantly enhanced the relative expression of miR-126 in the BLS cells after infection (P<0.0001). MiR-126 overexpression inhibited the proliferation, cloning, migration, and invasion of BLS cells, promoted cell apoptosis, and induced S phase arrest (all P<0.05). PIK3R2, p-PI3K, and p-Akt protein expressions were significantly decreased in the BLS cells infected with Lv-miR-126. Luciferase assays showed that miR-126 significantly inhibited the PIK3R2 3′ untranslated region (3′UTR) luciferase reporter activity (P<0.05). The anti-miR-126 + PIK3R2 siRNA group had significantly decreased PIK3R2, p-PI3K, and p-Akt expressions compared with those of anti-miR-126 alone, as well as significantly decreased proliferation, invasion, and metastasis and increased apoptosis compared with the anti-miR-126 group (all P<0.05). Additionally, proliferation, invasion, and metastasis were significantly increased, and cell apoptosis was decreased compared with the PIK3R2 siRNA group (all P<0.05).ConclusionOverexpression of miR-126 negatively regulated the target gene PIK3R2 and further inhibited the PI3K/Akt signaling pathway, thereby inhibiting proliferation, migration, and invasion and promoting apoptosis in BLS cells.

Resveratrol, curcumin, paclitaxel and miRNAs mediated regulation of PI3K/Akt/mTOR pathway: go four better to treat bladder cancer

“…Some microRNAs have tumor-suppressing role in cancers and their expression is down-regulated in most types of cancers including BC. miR-126 is one these microRNAs whose decreased expression in BC is associated with increased cell proliferation, migration and invasiveness [ 71 ]. Multiple targets of miR-126 have been discovered until now and their modulation by miR-126 has negative effects on BC cell viability.…”

“…Multiple targets of miR-126 have been discovered until now and their modulation by miR-126 has negative effects on BC cell viability. For instance, down-regulation of ADAM-9 mRNA causes inhibition of cell invasiveness [ 72 ] and by targeting PIK3R2 gene it modulates PI3K/Akt pathway and has a negative impacton cell’s proliferation [ 71 ]. MiR-125b-5p is another tumor suppressive miRNA.…”

“…KRAS is another target of miR-126 and its down-regulation by lncRNA ATB induces elevation in KRAS expression which activates AKT/mTOR signaling pathway by promoting phosphorylation-activation of PI3K, AKT and mTOR [ 56 ]. Re-expression of miR-126 by the transfection of recombinant-lentivirus vector in BLS cells facilitated apoptosis and suppressed tumor proliferation and migration [ 71 ]. This suggests the possible therapeutic importance of miR-126 in BC.…”

Na+/H+ exchanger regulatory factor 1 overexpression suppresses the malignant phenotype of MIAPaCa-2 pancreatic adenocarcinoma cells by downregulating Akt phosphorylation

“…Components of the PI3K/Akt/mTOR signaling pathway are commonly upregulated in malignant tumors, and increased Akt phosphorylation is commonly observed ( 19 ). The activation of Akt signaling is associated with cell proliferation, migration and invasion ( 20 ). Notably, it has been reported that NHERF1 inhibits the migration and invasion of human breast cancer cells via the PI3K/Akt signaling pathway ( 13 ).…”

Comparison of microRNA expression profiles in K562-cells-derived microvesicles and parental cells, and analysis of their roles in leukemia

“…For example, miR-27b, miR-24, miR-23b and miR-126* are known to be encoded by the chromosome 9 (59–61). In the present study, a considerable number of co-expressed microRNAs in MVs and K562 cells (including hsa-let-7a, hsa-let-7f, miR-126, miR-126*, miR-23b, miR-24, miR-27b and miR-7) were mapped to chromosome 9, while let-7b, miR-1249, miR-130b and miR-185 were mapped to chromosome 22.…”