title: PA28gamma emerges as a novel functional target of tumour suppressor microRNA-7 in non-small-cell lung cancer.
abstract: BACKGROUND
  MicroRNA-7 (miR-7) has been reported to be a tumour suppressor gene. However, whether it has a role in the growth of non-small-cell lung cancer (NSCLC) and what is its target involved in the tumour growth is still under investigation.
  
  
  METHODS
  NSCLC tissue sample, NSCLC cell lines and tissue microarray were investigated in this study. Total RNA, miRNA and protein were used for RT-PCR and western blot analysis. Immunohistochemistry was performed in tissues microarray. Cell culture and intervention experiments were performed in vitro and in vivo. Bioinformatics prediction, western blot and luciferase assay were identified the target of miR-7.
  
  
  RESULTS
  In this study, we found that the expression of miR-7 was significantly downregulated not only in NSCLC cell lines, but also in human NSCLC tissues compared with the matched adjacent tissues. Restoration of its expression through miR-7 mimics in A549 and H1299 NSCLC cells inhibited cell proliferation, colony formation, and cell-cycle progression in vitro. More importantly, the tumorigenicity in nude mice was reduced after administration of miR-7 in vivo. In advance, through bioinformatic analysis, luciferase assay and western blot, we identified a novel target of miR-7, PA28gamma (a proteasome activator) to be enrolled in the regulation with tumour. PA28gamma mRNA and protein levels are markedly upregulated in NSCLC cell lines and tumour samples, exhibiting a strong inverse relation with that of miR-7. In addition, knockdown of PA28gamma induced similar effects as overexpression of miR-7 in NSCLC cells. Furthermore, miR-7 overexpression or silencing of PA28gamma reduced the cyclinD1 expression at mRNA and protein level in NSCLC cell lines.
  
  
  CONCLUSIONS
  All these findings strongly imply that the overexpression of PA28gamma resulted from miR-7 downexpression in NSCLC has an important role in promoting cancer cell progress and consequently results in NSCLC growth. Thus, strategies targeting PA28gamma and/or miR-7 may become promising molecular therapies in NSCLC treatment.
authors.affiliation: 1] Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China [2] Biotherapy Research Center of Fudan University, Shanghai, People's Republic of China [3] Department of Hematology/Oncology, The Second Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.
authors.forename: S
authors.initials: S
authors.lastname: Xiong
authors.affiliation: 1] Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China [2] Biotherapy Research Center of Fudan University, Shanghai, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: P
authors.initials: P
authors.lastname: Jiang
authors.affiliation: 1] Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China [2] Biotherapy Research Center of Fudan University, Shanghai, People's Republic of China.
authors.forename: R
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: J
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
authors.forename: J
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Chang
authors.affiliation: Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
authors.forename: D
authors.initials: D
authors.lastname: Ge
authors.affiliation: 1] Department of Immunology and Key Laboratory of Molecular Medicine of Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China [2] Biotherapy Research Center of Fudan University, Shanghai, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chu
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D063646:Carcinogenesis / Q000235:genetics / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D057809:HEK293 Cells; D064593:Heterografts; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D058990:Molecular Targeted Therapy; D046988:Proteasome Endopeptidase Complex / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D001324:Autoantigens; D019938:Cyclin D1; D035683:MicroRNAs; D046988:Proteasome Endopeptidase Complex; C099558:Ki antigen; C549242:MIRN7-1 microRNA, human; C549243:MIRN7 microRNA, mouse