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MicroRNA-21 regulates hTERT via PTEN in hypertrophic scar fibroblasts.

Zhu HY, Li C, Bai WD, Su LL, Liu JQ, Li Y, Shi JH, Cai WX, Bai XZ, Jia YH, Zhao B, Wu X, Li J, Hu DH - PLoS ONE (2014)

Bottom Line: As an important oncogenic miRNA, microRNA-21 (miR-21) is associated with various malignant diseases.Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation.In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN.

View Article: PubMed Central - PubMed

Affiliation: Department of Burns and Cutaneous Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China.

ABSTRACT

Background: As an important oncogenic miRNA, microRNA-21 (miR-21) is associated with various malignant diseases. However, the precise biological function of miR-21 and its molecular mechanism in hypertrophic scar fibroblast cells has not been fully elucidated.

Methodology/principal findings: Quantitative Real-Time PCR (qRT-PCR) analysis revealed significant upregulation of miR-21 in hypertrophic scar fibroblast cells compared with that in normal skin fibroblast cells. The effects of miR-21 were then assessed in MTT and apoptosis assays through in vitro transfection with a miR-21 mimic or inhibitor. Next, PTEN (phosphatase and tensin homologue deleted on chromosome ten) was identified as a target gene of miR-21 in hypertrophic scar fibroblast cells. Furthermore, Western-blot and qRT-PCR analyses revealed that miR-21 increased the expression of human telomerase reverse transcriptase (hTERT) via the PTEN/PI3K/AKT pathway. Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation. In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN. Finally, miR-21 and PTEN RNA expression levels in hypertrophic scar tissue samples were examined. Immunohistochemistry assays revealed an inverse correlation between PTEN and hTERT levels in high miR-21 RNA expressing-hypertrophic scar tissues.

Conclusions/significance: These data indicate that miR-21 regulates hTERT expression via the PTEN/PI3K/AKT signaling pathway by directly targeting PTEN, therefore controlling hypertrophic scar fibroblast cell growth. MiR-21 may be a potential novel molecular target for the treatment of hypertrophic scarring.

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Related in: MedlinePlus

Correlation between miR-21, PTEN and hTERT.A, Inverse correlation of miR-21 and PTEN expression of in HS tissues. B, Immunohistochemical staining of NS tissue; PTEN-positive (black) cells in which miR-21 is expressed at low levels; C, hTERT-positive cells (red) were slightly more prevalent than PTEN-positive cells in HS tissue that express miR-21 at moderate to high levels; D, the number of hTERT-positive cells was extremely high in the high-expressing miR-21 but low-expressing PTEN HS tissue.
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pone-0097114-g006: Correlation between miR-21, PTEN and hTERT.A, Inverse correlation of miR-21 and PTEN expression of in HS tissues. B, Immunohistochemical staining of NS tissue; PTEN-positive (black) cells in which miR-21 is expressed at low levels; C, hTERT-positive cells (red) were slightly more prevalent than PTEN-positive cells in HS tissue that express miR-21 at moderate to high levels; D, the number of hTERT-positive cells was extremely high in the high-expressing miR-21 but low-expressing PTEN HS tissue.

Mentions: It has previously been reported that miR-21 is frequently overexpressed in several types of cancer, including skin tumors [41]. In light of our observation that overexpression of miR-21 led to the downregulation of PTEN mRNA in HSBFs, we postulated an inverse correlation between miR-21 expression and PTEN mRNA expression in HS tissues. To validate this hypothesis, the PTEN mRNA and mature miR-21 expression levels were analyzed in 16 human hypertrophic scar tissue samples by qRT-PCR. As shown in Figure 6A, the expression levels of endogenous miR-21 correlated negatively with the expression levels of PTEN mRNA (Pearson's correlation coefficient  = −0.585; p = 0.017). These data provide further evidence of a functional link between miR-21 and PTEN in HS tissues.


MicroRNA-21 regulates hTERT via PTEN in hypertrophic scar fibroblasts.

Zhu HY, Li C, Bai WD, Su LL, Liu JQ, Li Y, Shi JH, Cai WX, Bai XZ, Jia YH, Zhao B, Wu X, Li J, Hu DH - PLoS ONE (2014)

Correlation between miR-21, PTEN and hTERT.A, Inverse correlation of miR-21 and PTEN expression of in HS tissues. B, Immunohistochemical staining of NS tissue; PTEN-positive (black) cells in which miR-21 is expressed at low levels; C, hTERT-positive cells (red) were slightly more prevalent than PTEN-positive cells in HS tissue that express miR-21 at moderate to high levels; D, the number of hTERT-positive cells was extremely high in the high-expressing miR-21 but low-expressing PTEN HS tissue.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016251&req=5

pone-0097114-g006: Correlation between miR-21, PTEN and hTERT.A, Inverse correlation of miR-21 and PTEN expression of in HS tissues. B, Immunohistochemical staining of NS tissue; PTEN-positive (black) cells in which miR-21 is expressed at low levels; C, hTERT-positive cells (red) were slightly more prevalent than PTEN-positive cells in HS tissue that express miR-21 at moderate to high levels; D, the number of hTERT-positive cells was extremely high in the high-expressing miR-21 but low-expressing PTEN HS tissue.
Mentions: It has previously been reported that miR-21 is frequently overexpressed in several types of cancer, including skin tumors [41]. In light of our observation that overexpression of miR-21 led to the downregulation of PTEN mRNA in HSBFs, we postulated an inverse correlation between miR-21 expression and PTEN mRNA expression in HS tissues. To validate this hypothesis, the PTEN mRNA and mature miR-21 expression levels were analyzed in 16 human hypertrophic scar tissue samples by qRT-PCR. As shown in Figure 6A, the expression levels of endogenous miR-21 correlated negatively with the expression levels of PTEN mRNA (Pearson's correlation coefficient  = −0.585; p = 0.017). These data provide further evidence of a functional link between miR-21 and PTEN in HS tissues.

Bottom Line: As an important oncogenic miRNA, microRNA-21 (miR-21) is associated with various malignant diseases.Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation.In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN.

View Article: PubMed Central - PubMed

Affiliation: Department of Burns and Cutaneous Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China.

ABSTRACT

Background: As an important oncogenic miRNA, microRNA-21 (miR-21) is associated with various malignant diseases. However, the precise biological function of miR-21 and its molecular mechanism in hypertrophic scar fibroblast cells has not been fully elucidated.

Methodology/principal findings: Quantitative Real-Time PCR (qRT-PCR) analysis revealed significant upregulation of miR-21 in hypertrophic scar fibroblast cells compared with that in normal skin fibroblast cells. The effects of miR-21 were then assessed in MTT and apoptosis assays through in vitro transfection with a miR-21 mimic or inhibitor. Next, PTEN (phosphatase and tensin homologue deleted on chromosome ten) was identified as a target gene of miR-21 in hypertrophic scar fibroblast cells. Furthermore, Western-blot and qRT-PCR analyses revealed that miR-21 increased the expression of human telomerase reverse transcriptase (hTERT) via the PTEN/PI3K/AKT pathway. Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation. In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN. Finally, miR-21 and PTEN RNA expression levels in hypertrophic scar tissue samples were examined. Immunohistochemistry assays revealed an inverse correlation between PTEN and hTERT levels in high miR-21 RNA expressing-hypertrophic scar tissues.

Conclusions/significance: These data indicate that miR-21 regulates hTERT expression via the PTEN/PI3K/AKT signaling pathway by directly targeting PTEN, therefore controlling hypertrophic scar fibroblast cell growth. MiR-21 may be a potential novel molecular target for the treatment of hypertrophic scarring.

Show MeSH
Related in: MedlinePlus