title: miR-143 overexpression impairs growth of human colon carcinoma xenografts in mice with induction of apoptosis and inhibition of proliferation.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are aberrantly expressed in human cancer and involved in the (dys)regulation of cell survival, proliferation, differentiation and death. Specifically, miRNA-143 (miR-143) is down-regulated in human colon cancer. In the present study, we evaluated the role of miR-143 overexpression on the growth of human colon carcinoma cells xenografted in nude mice (immunodeficient mouse strain: N: NIH(s) II-nu/nu).
  
  
  RESULTS
  HCT116 cells with stable miR-143 overexpression (Over-143) and control (Empty) cells were subcutaneously injected into the flanks of nude mice, and tumor growth was evaluated over time. Tumors arose ∼ 14 days after tumor cell implantation, and the experiment was ended at 40 days after implantation. miR-143 was confirmed to be significantly overexpressed in Over-143 versus Empty xenografts, by TaqMan® Real-time PCR (p<0.05). Importantly, Over-143 xenografts displayed slower tumor growth compared to Empty xenografts from 23 until 40 days in vivo (p<0.05), with final volumes of 928±338 and 2512±387 mm(3), respectively. Evaluation of apoptotic proteins showed that Over-143 versus Empty xenografts displayed reduced Bcl-2 levels, and increased caspase-3 activation and PARP cleavage (p<0.05). In addition, the incidence of apoptotic tumor cells, assessed by TUNEL, was increased in Over-143 versus Empty xenografts (p<0.01). Finally, Over-143 versus Empty xenografts displayed significantly reduced NF-κB activation and ERK5 levels and activation (p<0.05), as well as reduced proliferative index, evaluated by Ki-67 immunohistochemistry (p<0.01).
  
  
  CONCLUSIONS
  Our results suggest that reduced tumor volume in Over-143 versus Empty xenografts may result from increased apoptosis and decreased proliferation induced by miR-143. This reinforces the relevance of miR-143 in colon cancer, indicating an important role in the control of in vivo tumor progression, and suggesting that miR-143 may constitute a putative novel therapeutic tool for colon cancer treatment that warrants further investigation.
authors: Research Institute for Medicines and Pharmaceutical Sciences-iMed.UL, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors: Pedro M
authors: PM
authors: Borralho
authors: André E S
authors: AE
authors: Simões
authors: Sofia E
authors: SE
authors: Gomes
authors: Raquel T
authors: RT
authors: Lima
authors: Tânia
authors: T
authors: Carvalho
authors: Duarte M S
authors: DM
authors: Ferreira
authors: Maria H
authors: MH
authors: Vasconcelos
authors: Rui E
authors: RE
authors: Castro
authors: Cecília M P
authors: CM
authors: Rodrigues
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D045325:HCT116 Cells; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: C542359:MIRN143 microRNA, human; D035683:MicroRNAs