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miR-93 promotes cell proliferation in gliomas through activation of PI3K/Akt signaling pathway.

Jiang L, Wang C, Lei F, Zhang L, Zhang X, Liu A, Wu G, Zhu J, Song L - Oncotarget (2015)

Bottom Line: Multiple regulators, such as phosphatase and tensin homolog (PTEN) and PH domain leucine rich repeat protein phosphatases (PHLPP), have also found to be involved in suppression of the PI3K/Akt signaling pathway.Furthermore, we found that overexpressing miR-93 promoted, but inhibition of miR-93 reduced, glioma cell proliferation and cell-cycle progression.Therefore, our results suggest that miR-93 might play an important role in glioma progression and uncover a novel mechanism for constitutive PI3K/Akt activation in gliomas.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathophysiology, Guangzhou Medical University, Guangzhou 510182, China.

ABSTRACT
The PI3K/Akt signaling pathway is frequently activated in various human cancer types and plays essential roles in development and progression of cancers. Multiple regulators, such as phosphatase and tensin homolog (PTEN) and PH domain leucine rich repeat protein phosphatases (PHLPP), have also found to be involved in suppression of the PI3K/Akt signaling pathway. However, how suppressive effects mediated by these regulators are concomitantly disrupted in cancers, which display constitutively activated PI3K/Akt signaling, remains puzzling. In the present study, we reported that the expression of miR-93 was markedly upregulated in glioma cell lines and clinical glioma tissues. Statistical analysis revealed that miR-93 levels significantly correlated with clinicopathologic grade and overall survival in gliomas. Furthermore, we found that overexpressing miR-93 promoted, but inhibition of miR-93 reduced, glioma cell proliferation and cell-cycle progression. We demonstrated that miR-93 activated PI3K/Akt signaling through directly suppressing PTEN, PHLPP2 and FOXO3 expression via targeting their 3'UTRs. Therefore, our results suggest that miR-93 might play an important role in glioma progression and uncover a novel mechanism for constitutive PI3K/Akt activation in gliomas.

No MeSH data available.


Related in: MedlinePlus

Suppression of PHLPP2, FOXO3, and PTEN by miR-93 is essential for glioma cell proliferation(A) Western blotting analysis of the protein levels of PTEN, PHLPP2 and FOXO3 in indicated cells transfected with specific siRNA, respectively. (B) The mRNA expression levels of Cyclin D1 and p27Kip1, determined by real-time PCR analysis. (C) Quantification of colonies determined by colony formation assay in indicated glioma cell lines. (D) Quantification of colonies determined by anchorage-independent growth ability assay in indicated glioma cell lines. (E) Quantification of BrdUrd incorporating-cells in indicated glioma cell lines. Experiments were repeated at least 3 times with similar results, and error bars represent ± SD. *P < 0.05.
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Figure 5: Suppression of PHLPP2, FOXO3, and PTEN by miR-93 is essential for glioma cell proliferation(A) Western blotting analysis of the protein levels of PTEN, PHLPP2 and FOXO3 in indicated cells transfected with specific siRNA, respectively. (B) The mRNA expression levels of Cyclin D1 and p27Kip1, determined by real-time PCR analysis. (C) Quantification of colonies determined by colony formation assay in indicated glioma cell lines. (D) Quantification of colonies determined by anchorage-independent growth ability assay in indicated glioma cell lines. (E) Quantification of BrdUrd incorporating-cells in indicated glioma cell lines. Experiments were repeated at least 3 times with similar results, and error bars represent ± SD. *P < 0.05.

Mentions: To evaluate the effects of PTEN, PHLPP2 and FOXO3 on miR-93-induced glioma progression, we suppressed endogenous PTEN, PHLPP2 or FOXO3 expression with specific siRNAs (Figure 5A). As shown Figure 5B, silencing PTEN, PHLPP2 or FOXO3 in miR-93 inhibitor transfected cells increased the expression level of Cyclin D1 and decreased the expression of p27Kip. The colony formation assay indicated that silencing PTEN, PHLPP2 or FOXO3 in miR-93 inhibitor transfected cells increased proliferation of glioma cells (Figure 5C). The anchorage-independent growth assay and BrdUrd incorporation assay both showed the similar results (Figure 5D and 5E). These results suggested that silencing PTEN, PHLPP2 or FOXO3 expression in miR-93-repressed cells could reverse the inhibitory effect of the miR-93 inhibitor on glioma cell proliferation and tumorigenesis.


miR-93 promotes cell proliferation in gliomas through activation of PI3K/Akt signaling pathway.

Jiang L, Wang C, Lei F, Zhang L, Zhang X, Liu A, Wu G, Zhu J, Song L - Oncotarget (2015)

Suppression of PHLPP2, FOXO3, and PTEN by miR-93 is essential for glioma cell proliferation(A) Western blotting analysis of the protein levels of PTEN, PHLPP2 and FOXO3 in indicated cells transfected with specific siRNA, respectively. (B) The mRNA expression levels of Cyclin D1 and p27Kip1, determined by real-time PCR analysis. (C) Quantification of colonies determined by colony formation assay in indicated glioma cell lines. (D) Quantification of colonies determined by anchorage-independent growth ability assay in indicated glioma cell lines. (E) Quantification of BrdUrd incorporating-cells in indicated glioma cell lines. Experiments were repeated at least 3 times with similar results, and error bars represent ± SD. *P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4480752&req=5

Figure 5: Suppression of PHLPP2, FOXO3, and PTEN by miR-93 is essential for glioma cell proliferation(A) Western blotting analysis of the protein levels of PTEN, PHLPP2 and FOXO3 in indicated cells transfected with specific siRNA, respectively. (B) The mRNA expression levels of Cyclin D1 and p27Kip1, determined by real-time PCR analysis. (C) Quantification of colonies determined by colony formation assay in indicated glioma cell lines. (D) Quantification of colonies determined by anchorage-independent growth ability assay in indicated glioma cell lines. (E) Quantification of BrdUrd incorporating-cells in indicated glioma cell lines. Experiments were repeated at least 3 times with similar results, and error bars represent ± SD. *P < 0.05.
Mentions: To evaluate the effects of PTEN, PHLPP2 and FOXO3 on miR-93-induced glioma progression, we suppressed endogenous PTEN, PHLPP2 or FOXO3 expression with specific siRNAs (Figure 5A). As shown Figure 5B, silencing PTEN, PHLPP2 or FOXO3 in miR-93 inhibitor transfected cells increased the expression level of Cyclin D1 and decreased the expression of p27Kip. The colony formation assay indicated that silencing PTEN, PHLPP2 or FOXO3 in miR-93 inhibitor transfected cells increased proliferation of glioma cells (Figure 5C). The anchorage-independent growth assay and BrdUrd incorporation assay both showed the similar results (Figure 5D and 5E). These results suggested that silencing PTEN, PHLPP2 or FOXO3 expression in miR-93-repressed cells could reverse the inhibitory effect of the miR-93 inhibitor on glioma cell proliferation and tumorigenesis.

Bottom Line: Multiple regulators, such as phosphatase and tensin homolog (PTEN) and PH domain leucine rich repeat protein phosphatases (PHLPP), have also found to be involved in suppression of the PI3K/Akt signaling pathway.Furthermore, we found that overexpressing miR-93 promoted, but inhibition of miR-93 reduced, glioma cell proliferation and cell-cycle progression.Therefore, our results suggest that miR-93 might play an important role in glioma progression and uncover a novel mechanism for constitutive PI3K/Akt activation in gliomas.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathophysiology, Guangzhou Medical University, Guangzhou 510182, China.

ABSTRACT
The PI3K/Akt signaling pathway is frequently activated in various human cancer types and plays essential roles in development and progression of cancers. Multiple regulators, such as phosphatase and tensin homolog (PTEN) and PH domain leucine rich repeat protein phosphatases (PHLPP), have also found to be involved in suppression of the PI3K/Akt signaling pathway. However, how suppressive effects mediated by these regulators are concomitantly disrupted in cancers, which display constitutively activated PI3K/Akt signaling, remains puzzling. In the present study, we reported that the expression of miR-93 was markedly upregulated in glioma cell lines and clinical glioma tissues. Statistical analysis revealed that miR-93 levels significantly correlated with clinicopathologic grade and overall survival in gliomas. Furthermore, we found that overexpressing miR-93 promoted, but inhibition of miR-93 reduced, glioma cell proliferation and cell-cycle progression. We demonstrated that miR-93 activated PI3K/Akt signaling through directly suppressing PTEN, PHLPP2 and FOXO3 expression via targeting their 3'UTRs. Therefore, our results suggest that miR-93 might play an important role in glioma progression and uncover a novel mechanism for constitutive PI3K/Akt activation in gliomas.

No MeSH data available.


Related in: MedlinePlus