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. 2015 Jun 23;10(6):e0130124.
doi: 10.1371/journal.pone.0130124. eCollection 2015.

MicroRNA-137 Contributes to Dampened Tumorigenesis in Human Gastric Cancer by Targeting AKT2

Liping Wu  1 , Jingtao Chen  1 , Chunsheng Ding  1 , Shutang Wei  1 , Yanhong Zhu  1 , Wenyi Yang  1 , Xiaoyang Zhang  1 , Xuejv Wei  1 , Dazheng Han  1
Affiliations

MicroRNA-137 Contributes to Dampened Tumorigenesis in Human Gastric Cancer by Targeting AKT2

Liping Wu et al. PLoS One. .

Retraction in

Abstract

MiRNAs play important roles in tumorigenesis. This study focused on exploring the effects and regulation mechanism of miRNA-137 on the biological behaviors of gastric cancer. Total RNA was extracted from tissues of 100 patients with gastric cancer and from four gastric cancer cell lines. Expression of miR-137 was detected by real-time PCR from 100 patients. The effects of miR-137 overexpression on gastric cancer cells' proliferation, apoptosis, migration and invasion ability were investigated in vitro and in vivo. The target gene of miR-137 was predicted by Targetscan on line software, screened by dual luciferase reporter gene assay and demonstrated by western blot. As a result, the expression of miR-137 was significant reduced in gastric cancer cell line HGC-27, HGC-803, SGC-7901 and MKN-45 as well as in gastric cancer tissues compared with GES-1 cell or matched adjacent non-neoplastic tissues (p<0.001). The re-introduction of miR-137 into gastric cancer cells was able to inhibit cell proliferation, migration and invasion. The in vivo experiments demonstrated that the miR-137 overexpression can reduce the gastric cancer cell proliferation and metastasis. Bioinformatic and western blot analysis indicated that the miR-137 acted as tumor suppressor roles on gastric cancer cells through targeting AKT2 and further affecting the Bad and GSK-3β. In conclusion, the miR-137 which is frequently down-regulated in gastric cancer is potentially involved in gastric cancer tumorigenesis and metastasis by regulating AKT2 related signal pathways.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. MiR-137 expression in gastric cancer cells and clinical samples.
A. MiR-137 expression ingastric cancer cell lines (HGC-27, SGC-7901, SGC-7901 and MKN-45) and gastric epithelial cell (GES-1). B. Four patients diagnosed as gastric cancer by H&E staining (original magnification, x100). C/D. MiR-137 expression in 100 clinical patients. E. Expression levelsof miR-137 in I–II stages (n = 38) versusIII–IV stages (n = 62) of the gastric cancer patients.
Fig 2
Fig 2. Overexpression of miR-137 inhibits gastric cancer cell proliferation.
A. Real-time PCR was performed to detect the miR-137 expression in HGC-27 and SGC-7901 cells treated with miR-137 mimic or scramble mimic. B. Growth of HGC-27 and SGC-7901 cells was shown after transfection with miR-137 mimic or scramble mimic or no transfection. The growth index was assessed at 0, 1, 2, 3 and 4 days. The bars represent the mean ± SD of three independent experiments (*** means P< 0.001). C. HGC-27and SGC-7901 cells were stained with PE Annexin V and 7-AAD 72 h after treatment with miR-137mimics or scramble. Early apoptotic cells are shown in the right quadrant. D. Representative figure of in vivo experiments. The tumor in miR-137 overexpression group is much smaller than the scramble. E. HE staining of mice tumor. F/G. Tumor volume and weight were calculated and all data are shown as mean ± SD. These results showed that both the tumor volume and weight was significantly reduced by miR-137 overexpression. These result verified that the miR-137 overexpression can suppress tumor growth in vivo (*: p<0.05;**: p<0.01; ***:p<0.001).
Fig 3
Fig 3. Overexpression of miR-137 inhibits gastric cancer cell migration and invasion.
A. SGC-7901 and HGC-27 cells were not transfected or transfected with miR-137 mimics or scramble for 24 hours, and wounds were made. The relative ratio of wound closure per field is shown. As a result, cells transfected with miR-137 showed a significantly higher migrate speed compared to the control. B. HGC-27 and SGC-7901 cells were not transfected or transfected with miR-137 mimics or scramble for 24 hours, and transwell invasion assay was performed. The relative ratio of invasive cells per field is shown. Magnification for identification of migration is ×400 and invasion is ×40. This result demonstrated that the migration ability of lung cancer cells can be inhibited by miR-137 overexpression. C. Bioluminescentimaging (left) and the number of lung metastasis per mice (middle) showed that the miR-137 can suppress metastasis in vivo. The HE staining showed that the metastasis in mice lung (right).
Fig 4
Fig 4. AKT2 is experimentally validated as a direct target of miR-137.
A. Sequence of the miR-137 binding sites within the human AKT2 3’-UTR and a schematic diagram of the reporter constructs showing the entire AKT2 3’-UTR sequence (AKT2_WT) and the mutated AKT2 3’-UTR sequence (M1, M2). B. Luciferase activity of the AKT2_WT reporter and the AKT2_MUT reporter in the presence of 10 nmol/L of miR-137 mimic or scramble. C. Relative expression of AKT2 in HGC-27 and SGC-7901 cells not transfected or transfected with miR-137 mimics or scramble 24 hours. D. Immunoblotting of AKT2 in HGC-27 and SGC-7901 cells not transfected or transfected with miR-137 mimic or scramble. All data are shown as mean ± SD. E. Immunoblotting of Bad, GSK-3β, p-Bad and p-GSK-β.fWestern blot analysis of AKT2 protein level in 12 GC patients in whom miR-137 was down regulatedin their GC tissues.
Fig 5
Fig 5. miR-137 active cell apoptosis and negatively regulate cell invasion by targeting AKT2.
A. AKT2 protein level was assessed in GC cells treated by overexpression of miR-137 and/ or AKT2. B. AKT2 restoration leads to a suppression of apoptosis in GC cells while miR-137 promotes apoptosis. C. AKT2 restoration actives the apoptosis and invasion of GC cells while miR-137 showed opposite effects. Representative images are shown. The normalized ratio of invasive cells is shown in the bottom panels. In Fig 5, “miR-137” represents the cells transfected by miR-137 and pcDNA 3.1 empty vector. “AKT2_oe” represents the cells transfected by AKT2 overexpression vector. “miR-137 +AKT2_oe” represents the cells co-transfected by miR-137 and AKT2 overexpression vector. “Scr” represents the cells transfected with mimic negative control and pcDNA 3.1 empty vector.
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References

    1. Mathers CD, Shibuya K, Boschi-Pinto C, Lopez AD, Murray CJ. (2002) Global and regional estimates of cancer mortality and incidence by site: I. Application of regional cancer survival model to estimate cancer mortality distribution by site. BMC Cancer 2:36 - PMC - PubMed
    1. Krol J, Loedige I, Filipowicz W. (2010) The widespread regulation of microRNA biogenesis, function and decay. Nat Rev Genet 11(9):597–610. 10.1038/nrg2843 - DOI - PubMed
    1. Herranz H, Cohen SM. (2010) MicroRNAs and gene regulatory networks: managing the impact of noise in biological systems. Genes Dev 24(13):1339–1344. 10.1101/gad.1937010 - DOI - PMC - PubMed
    1. Zhang T, Wang Q, Zhao D, Cui Y, Cao B, Guo L et al. (2011) The oncogenetic role of microRNA-31 as a potential biomarker in oesophageal squamous cell carcinoma. Clin Sci (Lond) 121(10):437–447. 10.1042/CS20110207 - DOI - PubMed
    1. Wang R, Wang ZX, Yang JS, Pan X, De W, Chen LB. (2011) MicroRNA-451 functions as a tumor suppressor in human non-small cell lung cancer by targeting ras-related protein 14 (RAB14). Oncogene 30(23):2644–2658. 10.1038/onc.2010.642 - DOI - PubMed

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Grants and funding

This work was supported by Medical science and technology research projects of Henan province, China (2011030004).