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miR-122-mediated translational repression of PEG10 and its suppression in human hepatocellular carcinoma.

Shyu YC, Lee TL, Lu MJ, Chen JR, Chien RN, Chen HY, Lin JF, Tsou AP, Chen YH, Hsieh CW, Huang TS - J Transl Med (2016)

Bottom Line: Several studies have found an association between downregulation of miR-122, a liver-specific miRNA, and upregulation of paternally expressed gene 10 (PEG10) in HCC; however, the correlation between low miR-122 and high PEG10 levels still remains to be defined and require more investigations to evaluate their performance as an effective prognostic biomarker for HCC.In miR-122 knockout mice and HCC patients, the deficiency of miR-122 was associated with HCC progression.The expression of PEG10 was increased in 57.3 % of HCC as compared to paired non-cancerous tissue samples.

View Article: PubMed Central - PubMed

Affiliation: Community Medicine Research Center, Keelung Chang Gung Memorial Hospital, Keelung 204, Taiwan.

ABSTRACT

Background: Hepatocellular carcinoma (HCC), a primary liver malignancy, is the most common cancer in males and fourth common cancer in females in Taiwan. HCC patients usually have a poor prognosis due to late diagnosis. It has been classified as a complex disease because of the heterogeneous phenotypic and genetic traits of the patients and a wide range of risk factors. Micro (mi)RNAs regulate oncogenes and tumor suppressor genes that are known to be dysregulated in HCC. Several studies have found an association between downregulation of miR-122, a liver-specific miRNA, and upregulation of paternally expressed gene 10 (PEG10) in HCC; however, the correlation between low miR-122 and high PEG10 levels still remains to be defined and require more investigations to evaluate their performance as an effective prognostic biomarker for HCC.

Methods: An in silico approach was used to isolate PEG10, a potential miR-122 target implicated in HCC development. miR-122S binding sites in the PEG10 promoter were evaluated with a reporter assay. The regulation of PEG10 by miR-122S overexpression was examined by quantitative RT-PCR, western blotting, and immunohistochemistry in miR-122 knockout mice and liver tissue from HCC patients. The relationship between PEG10 expression and clinicopathologic features of HCC patients was also evaluated.

Results: miR-122 downregulated the expression of PEG10 protein through binding to 3'-untranslated region (UTR) of the PEG10 transcript. In miR-122 knockout mice and HCC patients, the deficiency of miR-122 was associated with HCC progression. The expression of PEG10 was increased in 57.3 % of HCC as compared to paired non-cancerous tissue samples. However, significant upregulation was detected in 56.5 % of patients and was correlated with Okuda stage (P = 0.05) and histological grade (P = 0.001).

Conclusions: miR-122 suppresses PEG10 expression via direct binding to the 3'-UTR of the PEG10 transcript. Therefore, while PEG10 could not be an ideal diagnostic biomarker for HCC but its upregulation in HCC tissue still has predictive value for HCC prognosis.

No MeSH data available.


Related in: MedlinePlus

PEG10 is regulated by miR-122 at the post-transcriptional level in 293T and HepG2 cells. a PEG10 mRNA levels were detected by qRT-PCR and normalized to that of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in 293T cells. b Western blot analysis of PEG10 expression in 293T and HepG2 cells transfected with miR-122S and miR-122AS. Tubulin was used as the loading control. c Overexpression of miR-122 upon HepG2 cells transfection with miR-122S and miR-122AS, as determined by qRT-PCR
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Fig1: PEG10 is regulated by miR-122 at the post-transcriptional level in 293T and HepG2 cells. a PEG10 mRNA levels were detected by qRT-PCR and normalized to that of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in 293T cells. b Western blot analysis of PEG10 expression in 293T and HepG2 cells transfected with miR-122S and miR-122AS. Tubulin was used as the loading control. c Overexpression of miR-122 upon HepG2 cells transfection with miR-122S and miR-122AS, as determined by qRT-PCR

Mentions: To investigate the relationship between miR-122 and PEG10, pre-miR-122 was overexpressed in 293T and HepG2 cells and determined the mRNA and protein expression levels of PEG10 by qRT-PCR and western blotting, respectively. The effect of miR-122 on PEG10 mRNA levels was examined by quantifying the mRNA levels of PEG10 as well as miR-122S and miR-122AS in cells transiently transfected with pSM-miR-122S or pSM-miR-122AS constructs (Fig. 1). The mRNA level of PEG10 was unaltered upon miR-122 or miR-122AS overexpression in 293T cells (Fig. 1a). The protein level of PEG10 was only significantly decreased when miR-122 overexpressed but not miR-122AS in both 293T and HepG2 cells (Fig. 1b, c).Fig. 1


miR-122-mediated translational repression of PEG10 and its suppression in human hepatocellular carcinoma.

Shyu YC, Lee TL, Lu MJ, Chen JR, Chien RN, Chen HY, Lin JF, Tsou AP, Chen YH, Hsieh CW, Huang TS - J Transl Med (2016)

PEG10 is regulated by miR-122 at the post-transcriptional level in 293T and HepG2 cells. a PEG10 mRNA levels were detected by qRT-PCR and normalized to that of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in 293T cells. b Western blot analysis of PEG10 expression in 293T and HepG2 cells transfected with miR-122S and miR-122AS. Tubulin was used as the loading control. c Overexpression of miR-122 upon HepG2 cells transfection with miR-122S and miR-122AS, as determined by qRT-PCR
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4930569&req=5

Fig1: PEG10 is regulated by miR-122 at the post-transcriptional level in 293T and HepG2 cells. a PEG10 mRNA levels were detected by qRT-PCR and normalized to that of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in 293T cells. b Western blot analysis of PEG10 expression in 293T and HepG2 cells transfected with miR-122S and miR-122AS. Tubulin was used as the loading control. c Overexpression of miR-122 upon HepG2 cells transfection with miR-122S and miR-122AS, as determined by qRT-PCR
Mentions: To investigate the relationship between miR-122 and PEG10, pre-miR-122 was overexpressed in 293T and HepG2 cells and determined the mRNA and protein expression levels of PEG10 by qRT-PCR and western blotting, respectively. The effect of miR-122 on PEG10 mRNA levels was examined by quantifying the mRNA levels of PEG10 as well as miR-122S and miR-122AS in cells transiently transfected with pSM-miR-122S or pSM-miR-122AS constructs (Fig. 1). The mRNA level of PEG10 was unaltered upon miR-122 or miR-122AS overexpression in 293T cells (Fig. 1a). The protein level of PEG10 was only significantly decreased when miR-122 overexpressed but not miR-122AS in both 293T and HepG2 cells (Fig. 1b, c).Fig. 1

Bottom Line: Several studies have found an association between downregulation of miR-122, a liver-specific miRNA, and upregulation of paternally expressed gene 10 (PEG10) in HCC; however, the correlation between low miR-122 and high PEG10 levels still remains to be defined and require more investigations to evaluate their performance as an effective prognostic biomarker for HCC.In miR-122 knockout mice and HCC patients, the deficiency of miR-122 was associated with HCC progression.The expression of PEG10 was increased in 57.3 % of HCC as compared to paired non-cancerous tissue samples.

View Article: PubMed Central - PubMed

Affiliation: Community Medicine Research Center, Keelung Chang Gung Memorial Hospital, Keelung 204, Taiwan.

ABSTRACT

Background: Hepatocellular carcinoma (HCC), a primary liver malignancy, is the most common cancer in males and fourth common cancer in females in Taiwan. HCC patients usually have a poor prognosis due to late diagnosis. It has been classified as a complex disease because of the heterogeneous phenotypic and genetic traits of the patients and a wide range of risk factors. Micro (mi)RNAs regulate oncogenes and tumor suppressor genes that are known to be dysregulated in HCC. Several studies have found an association between downregulation of miR-122, a liver-specific miRNA, and upregulation of paternally expressed gene 10 (PEG10) in HCC; however, the correlation between low miR-122 and high PEG10 levels still remains to be defined and require more investigations to evaluate their performance as an effective prognostic biomarker for HCC.

Methods: An in silico approach was used to isolate PEG10, a potential miR-122 target implicated in HCC development. miR-122S binding sites in the PEG10 promoter were evaluated with a reporter assay. The regulation of PEG10 by miR-122S overexpression was examined by quantitative RT-PCR, western blotting, and immunohistochemistry in miR-122 knockout mice and liver tissue from HCC patients. The relationship between PEG10 expression and clinicopathologic features of HCC patients was also evaluated.

Results: miR-122 downregulated the expression of PEG10 protein through binding to 3'-untranslated region (UTR) of the PEG10 transcript. In miR-122 knockout mice and HCC patients, the deficiency of miR-122 was associated with HCC progression. The expression of PEG10 was increased in 57.3 % of HCC as compared to paired non-cancerous tissue samples. However, significant upregulation was detected in 56.5 % of patients and was correlated with Okuda stage (P = 0.05) and histological grade (P = 0.001).

Conclusions: miR-122 suppresses PEG10 expression via direct binding to the 3'-UTR of the PEG10 transcript. Therefore, while PEG10 could not be an ideal diagnostic biomarker for HCC but its upregulation in HCC tissue still has predictive value for HCC prognosis.

No MeSH data available.


Related in: MedlinePlus