title: Krill oil extract suppresses cell growth and induces apoptosis of human colorectal cancer cells.
abstract: BACKGROUND
  Colorectal cancer (CRC) is the third most common cancer in the world. The current available treatments for CRC include surgery, chemotherapy and radiotherapy. However, surgery is only useful when the disease is diagnosed at the earlier stage. Chemotherapy and radiotherapy are associated with numerous side effects that decrease the patients' quality of life. Safer, effective alternatives, such as natural compounds, to chemotherapy are desirable. This study assessed the efficacy of free fatty acid (FFA) extract of krill oil on three human CRC cells lines.
  
  
  METHODS
  HCT-15, SW-480 and Caco-2 cells were treated with the FFA extracts of krill oil and fish oil for 48 h while treatments with the bioactive omega-3 polyunsaturated fatty acids (LC n-3 PUFA) of these marine oils, eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) in comparison with a n-6 PUFA, arachnoid acid (AA, C20:4n-6) were up to 72 h at the concentrations of 50, 100, 150 and 200 μM. Effects of all the treatments on cell proliferation were assessed using a water-soluble tetrazolium-1 (WST-1) assay kit at 24, 48 and 72 h. Effects of FFA extract of krill oil and EPA on apoptosis and mitochondrial membrane potential were determined using commercial kits after 48 h of treatment.
  
  
  RESULTS
  Krill oil extract inhibited cell proliferation of all three cell lines in the similar manner as fish oil extract. A significant cell apoptosis and increase in mitochondrial membrane potential were observed after the treatment with krill oil extract. EPA at the concentration of 200 μM reduced significantly the proliferation of HCT-15 and SW-480 at 24, 48 and 72 h. In addition, EPA treatment (100 and 200 μM) resulted in significant cell apoptosis in all three cell lines. No significant changes were observed after treatment with DHA and AA.
  
  
  CONCLUSIONS
  Our results indicate that the FFA extract of krill oil maybe an effective chemotherapeutic agent to suppress proliferation and induce apoptosis in CRC cells through its bioactive constitute EPA. Although the exact mechanism of the pro-apoptotic properties of krill oil extract is unclear, mitochondrial pathway seems to be implicated.
authors: Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, P.O. Box 14428, Melbourne, VIC, 8001, Australia.
authors: Abilasha Gayani
authors: AG
authors: Jayathilake
authors: Melbourne Medical School Western Campus, Western Centre for Health Research and Education, Sunshine Hospital, St Albans, VIC, 3021, Australia.
authors: Paul Vincent
authors: PV
authors: Senior
authors: Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, P.O. Box 14428, Melbourne, VIC, 8001, Australia. xiao.su@vu.edu.au.
authors: Xiao Qun
authors: XQ
authors: Su
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology*; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D015179:Colorectal Neoplasms; D004281:Docosahexaenoic Acids / Q000737:chemistry / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000737:chemistry / Q000494:pharmacology; D033201:Euphausiacea / Q000737:chemistry*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D001688:Biological Products; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
keywords: Docosahexaenoic acid; Eicosapentaenoic acid; Human colorectal cancer cells; Krill oil extract