title: Cholesterol-conjugated let-7a mimics: antitumor efficacy on hepatocellular carcinoma in vitro and in a preclinical orthotopic xenograft model of systemic therapy.
abstract: BACKGROUND
  A major challenge to the clinical utility of let-7 for hepatocellular carcinoma (HCC) therapy is the lack of an effective carrier to target tumours. We confirmed the high transfection efficiency of cholesterol-conjugated let-7a miRNA mimics (Chol-let-7a) in human HCC cells, as well as their high affinity for liver tissue in nude mice. However, their antitumor efficacy via systemic delivery remains unknown.
  
  
  METHODS
  We explored the effects of Chol-let-7a on HCC in vitro and in vivo. Cell viability and mobility, let-7a abundance and the target ras genes was measured. Live-cell image and cell ultrastructure was observed. Antitumor efficacy in vivo was analyzed by ultrasonography, hispatholgogy and transmission electronic microscopy in a preclinical model of HCC orthotopic xenografts with systemic therapy.
  
  
  RESULTS
  Chol-let-7a inhibited the viability and mobility of HCC cells. Chol-let-7a was primarily observed in the cytoplasm and induced organelle changes, including autophagy. Mild changes were observed in the cells treated with negative control miRNA. Chol-let-7a reached HCC orthotopic tumours, significantly inhibited tumour growth, and prevented local invasion and metastasis. Compared to control tumours, Chol-let-7a-treated tumours showed more necrosis. Tumour cells showed no significant atypia, and mitoses were very rare after systemic Chol-let-7a therapy. Furthermore, let-7a abundance in orthotopic xenografts was coincident with a reduction in the expression of 3 human ras mRNAs and RAS proteins.
  
  
  CONCLUSIONS
  Chol-let-7a exerted significant antitumor effects by down-regulating all human ras genes at the transcriptional and translational levels. Chol-let-7a inhibited cell proliferation, growth, and metastasis, and mainly functioned in the cytoplasm. Chol-let-7a represents a potential useful modified molecule for systemic HCC therapy.
authors.forename: Yang Ming
authors.initials: YM
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Xia
authors.forename: Wei
authors.initials: W
authors.lastname: Dai
authors.forename: Hua Ye
authors.initials: HY
authors.lastname: Han
authors.forename: Yu Xue
authors.initials: YX
authors.lastname: Dong
authors.forename: Jiong
authors.initials: J
authors.lastname: Cai
authors.forename: Xuan
authors.initials: X
authors.lastname: Zeng
authors.forename: Feng Yu
authors.initials: FY
authors.lastname: Luo
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Yuan Zhi
authors.initials: YZ
authors.lastname: Li
authors.affiliation: Department of Pathology, Peking Union Medical College (PUMC) Hospital, PUMC & Chinese Academy of Medical Sciences (CAMS), Beijing, China. xhblk@163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Guan
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000737:chemistry / Q000627:therapeutic use*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D009361:Neoplasm Invasiveness; D015854:Up-Regulation / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D035683:MicroRNAs; C542687:mirnlet7 microRNA, mouse; D002784:Cholesterol