Fish oil prevents colon cancer by modulation of structure and function of mitochondria

Biomed Pharmacother. 2016 Aug;82:90-7. doi: 10.1016/j.biopha.2016.04.045. Epub 2016 May 7.

Abstract

Cancer cells are more susceptible to metabolic perturbations due to impaired electron transport chain (ETC) that promote uncontrolled proliferation. Mitochondria play a pivotal role in bioenergetics and apoptosis, hence are considered as a promising target in tumor cell eradication. Therefore, the present study is designed to elucidate chemopreventive action of fish oil (FO) in combination with corn oil (CO) on mitochondria in colorectal cancer (CRC). Male Wistar rats were divided into groups depending on dietary regimen-Control group, FO+CO(1:1) and FO+CO(2.5:1). These groups were further subdivided depending on whether these received a weekly intraperitoneal injection of ethylenediamine tetra-acetic acid (EDTA) or N,N-dimethylhydrazine dihydrochloride (DMH) for a period of 4 weeks. The animals sacrificed 48h and 16 weeks after EDTA/DMH treatment constituted initiation and post-initiation phase respectively. The structural and functional alterations in mitochondria were evaluated using transmission electron microscopy (TEM) and by assaying electron transport chain (ETC) enzymes. Mitochondrial lipid composition and cholesterol levels were also assessed. DMH treatment led to mitochondrial degeneration, disrupted cristae and a significant decrease in ETC complexes suggestive of metabolic reprogramming. Moreover, an increase in cholesterol and cardiolipin (CL) levels in post-initiation phase led to evasion of apoptosis. FO in both the ratios resulted in stabilization and increase in number of mitochondria, however, FO+CO(2.5:1)+DMH group also exhibited mitophagy and crystolysis alongwith altered dynamics in ETC which facilitated apoptosis. It also decreased cholesterol and CL levels to increase apoptosis. Fish oil targets mitochondria in a dose dependent manner that augments apoptosis and hence attenuates carcinogenesis.

Keywords: Colorectal cancer (CRC); Corn oil (CO); Fish oil (FO); N,N-Dimethylhydrazine dihydrochloride (DMH); n-3 and n-6 PUFAs (polyunsaturated fatty acids).

MeSH terms

  • Animals
  • Cardiolipins / metabolism
  • Cell Separation
  • Cell Survival / drug effects
  • Cholesterol / metabolism
  • Colonic Neoplasms / prevention & control*
  • Corn Oil / pharmacology
  • Electron Transport / drug effects
  • Enterocytes / drug effects
  • Enterocytes / pathology
  • Fish Oils / pharmacology
  • Fish Oils / therapeutic use*
  • Male
  • Mitochondria / drug effects
  • Mitochondria / metabolism*
  • Mitochondria / ultrastructure*
  • Rats, Wistar

Substances

  • Cardiolipins
  • Fish Oils
  • Corn Oil
  • Cholesterol