MicroRNA-375 targets AEG-1 in hepatocellular carcinoma and suppresses liver cancer cell growth in vitro and in vivo

Abstract

MicroRNAs (miRNAs) are believed to have fundamental roles in tumorigenesis and have great potential for the diagnosis and treatment of cancer. However, the roles of miRNAs in hepatocellular carcinogenesis are still not fully elucidated. We investigated the aberrantly expressed miRNAs involved in hepatoma by comparison of miRNA expression profiles in cancerous hepatocytes with normal primary human hepatocytes, and 37 dysregulated miRNAs were screened out by twofold change with a significant difference (Po0.05). Clustering analysis based on 13 miRNAs with changes over 15-folds showed that the miRNA expression patterns between the cancerous and normal hepatocytes were clearly different. Among the 13 miRNAs, we found that miR-375 was significantly downregulated in hepatocellular carcinoma (HCC) tissues and cell lines. Overexpression of miR-375 in liver cancer cells decreased cell proliferation, clonogenicity, migration/ invasion and also induced G1 arrest and apoptosis. To unveil the molecular mechanism of miR-375-mediated phenotype in hepatoma cells described above, we examined the putative targets using bioinformatics tools and found that astrocyte elevated gene-1 (AEG-1) was a potential target of miR-375. Then we demonstrated that miR-375 bound directly to the 3 0 -untranslated region of AEG-1 and inhibited the expression of AEG-1. TaqMan quantitative reverse transcriptase-PCR and western blot analysis showed that miR-375 expression was inversely correlated with AEG-1 expression in HCC tissues. Knockdown of AEG-1 by RNAi in HCC cells, similar to miR-375 overexpression, suppressed tumor properties. Ectopic expression of AEG-1, conversely, could partially reverse the antitumor effects of miR-375. In a mouse model, therapeutic administration of cholesterol-conjugated 2 0 -O-methyl-modified miR-375 mimics (Chol-miR-375) could significantly suppress the growth of hepatoma xenografts in nude mice. In conclusion, our findings indicate that miR-375 targets AEG-1 in HCC and suppresses liver cancer cell growth in vitro and in vivo, and highlight the therapeutic potential of miR-375 in HCC treatment.

Identification of microRNA expression profile related to lymph node status in women with early-stage grade 1–2 endometrial cancer

“…Finally, a recent review by Yan et al emphasized the emerging role of miR-375 in cancer and specified that miR-375 is frequently downregulated in multiple types of cancer, especially in hepatocarcinoma, 42 esophagus cancer, 43 osteosarcoma, 44 lung cancer, 45 and acts as a tumor suppressor by repressing many critical oncogenes such as PDK1, JAK2, IGF1R, 46 AEG-1, 42 and suppressing the PI3K/Akt pathway. 44 Furthermore, miR-375 might be used as a diagnostic and prognostic biomarker in various cancers.…”

The emerging role of astrocyte-elevated gene-1 in hepatocellular carcinoma (Review)

“…Based on the Barcelona Clinic Liver Cancer (BCLC) staging system, the expression of AEG-1 is gradually increased with stages from I to IV, and a statistically significant correlation (P<0.0001) was obtained between the AEG-1 expression level and the stage of HCC (16). Our research team also found that AEG-1 was upregulated in HCC tissues among 60 pairs of HCC samples (41).…”

The functional significance of microRNA-375 in human squamous cell carcinoma: aberrant expression and effects on cancer pathways

“…27 In hepatocellular carcinoma, it was reported that restoration of miR-375 in cancer cells decreased cell proliferation, clonogenicity, migration and invasion, and induced G1 arrest and apoptosis. 30 Interestingly, this report demonstrated that MTDH was directly regulated by miR-375, as it is in HNSCC. 16 Functional significance of miR-375 in human cancer T Kinoshita et al…”

“…16,17,[23][24][25][26][27][28][29][30][31][39][40][41][42] Downregulation of miR-375 has been reported for gastric cancer, cervical cancer, pancreatic ductal adenocarcinoma and hepatocellular carcinoma. 26,27,29,30,[43][44][45] In gastric cancer, ectopic expression of miR-375 in cancer cells reduced cell viability and induced apoptosis by targeting PDK1 and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein z (YWHAZ). 26 Overexpression of miR-375 suppressed gastric cancer cell proliferation in vitro and in vivo by targeting Janus kinase 2.…”

“…16,17 Other research groups also showed downregulation of miR-375 in HNSCC and ESCC and other types of human cancers. [18][19][20][21][22][23][24][25][26][27][28][29][30][31] In this review, we focus on HNSCC and ESCC and describe the aberrant expression of miRNAs in these cancers and the cancer pathways they may regulate in these diseases.…”