title: Preclinical analysis of the anti-tumor and anti-metastatic effects of Raf265 on colon cancer cells and CD26(+) cancer stem cells in colorectal carcinoma.
abstract: BACKGROUND
  In colorectal carcinoma (CRC), activation of the Raf/MEK/ERK signaling pathway is commonly observed. In addition, the commonly used 5FU-based chemotherapy in patients with metastatic CRC was found to enrich a subpopulation of CD26(+) cancer stem cells (CSCs). As activation of the Raf/MEK/ERK signaling pathway was also found in the CD26(+) CSCs and therefore, we hypothesized that an ATP-competitive pan-Raf inhibitor, Raf265, is effective in eliminating the cancer cells and the CD26(+) CSCs in CRC patients.
  
  
  METHODS
  HT29 and HCT116 cells were treated with various concentrations of Raf265 to study the anti-proliferative and apoptotic effects of Raf265. Anti-tumor effect was also demonstrated using a xenograft model. Cells were also treated with Raf265 in combination with 5FU to demonstrate the anti-migratory and invasive effects by targeting on the CD26(+) CSCs and the anti-metastatic effect of the combined treatment was shown in an orthotopic CRC model.
  
  
  RESULTS
  Raf265 was found to be highly effective in inhibiting cell proliferation and tumor growth through the inhibition of the RAF/MEK/ERK signaling pathway. In addition, anti-migratory and invasive effect was found with Raf265 treatment in combination with 5FU by targeting on the CD26(+) cells. Finally, the anti-tumor and anti-metastatic effect of Raf265 in combination with 5FU was also demonstrated.
  
  
  CONCLUSIONS
  This preclinical study demonstrates the anti-tumor and anti-metastatic activity of Raf265 in CRC, providing the basis for exploiting its potential use and combination therapy with 5FU in the clinical treatment of CRC.
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. chowakm@hku.hk.
authors.forename: Ariel K M
authors.initials: AK
authors.lastname: Chow
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. nathanc@hku.hk.
authors.forename: Nathan S M
authors.initials: NS
authors.lastname: Cheng
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. colin88@hku.hk.
authors.forename: Colin S C
authors.initials: CS
authors.lastname: Lam
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. luing@hku.hk.
authors.forename: Lui
authors.initials: L
authors.lastname: Ng
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. h0994148@hku.hk.
authors.forename: Sunny K M
authors.initials: SK
authors.lastname: Wong
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. u3002375@hku.hk.
authors.forename: Timothy M H
authors.initials: TM
authors.lastname: Wan
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. johnnyb@hku.hk.
authors.forename: Johnny H W
authors.initials: JH
authors.lastname: Man
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. cheung_hokwan@hotmail.com.
authors.forename: Alvin H K
authors.initials: AH
authors.lastname: Cheung
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. the@netvigator.com.
authors.forename: Thomas C C
authors.initials: TC
authors.lastname: Yau
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. jensenpoon@gmail.com.
authors.forename: Jensen T C
authors.initials: JT
authors.lastname: Poon
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. lawwl@hku.hk.
authors.forename: Wai-Lun
authors.initials: WL
authors.lastname: Law
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, Hong Kong. robertap@hku.hk.
authors.forename: Roberta W C
authors.initials: RW
authors.lastname: Pang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D000066673:Cell Self Renewal; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D004353:Drug Evaluation, Preclinical; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005472:Fluorouracil / Q000494:pharmacology; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism*; D048493:Proto-Oncogene Proteins B-raf / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D007093:Imidazoles; D011725:Pyridines; C559019:RAF265; D048493:Proto-Oncogene Proteins B-raf; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D005472:Fluorouracil