title: Evaluate the Antigenotoxicity and Anticancer Role of β-Sitosterol by Determining Oxidative DNA Damage and the Expression of Phosphorylated Mitogen-activated Protein Kinases', C-fos, C-jun, and Endothelial Growth Factor Receptor.
abstract: BACKGROUND
  Plant sterols are the major source of micronutrients and have not shown any obvious side effects in human. β-sitosterol is one of the most prevalent phytosterols which have been recorded in ancient medicinal history for its use in the treatment of many chronic diseases, especially cancer. The modulations of mitogen-activated protein kinases' (MAPKs') play a crucial role in the development of human renal cell carcinoma.
  
  
  OBJECTIVE
  The aim of the current study is to evaluate the antigenotoxic and anticancer role of β-sitosterol against renal carcinogen.
  
  
  METHODS
  The extent of DNA damage was assessed by the comet assay. The status of p-p38 MAPK, p-c-Jun N-terminal kinase, p-extracellular-signal regulating kinase (ERK), c-fos, c-jun, and endothelial growth factor receptor (EGFR) were analyzed by western blot and polymerase chain reaction techniques. To further confirm the inhibition of ERK-2 by β-sitosterol, molecular docking study was performed.
  
  
  RESULTS
  Extensive DNA damage in acute study and a significant increase in levels of p-MAPKs', c-fos, c-jun, and EGFR was observed in N-diethylnitrosamine (200 mg/kg bw) and ferric nitrilotriacetate (9 mg/kg bw) alone treated rats. Rats which are pretreated with 20 mg/kg bw of β-sitosterol reduced the DNA damage and restored the elevated levels of above-mentioned markers (p< 0.05). The binding free energy obtained for β-sitosterol for ERK-2 was found to be-5.578.
  
  
  CONCLUSIONS
  Therefore, it has been concluded that β-sitosterol has a strong potential against genotoxic as well as suppress neoplastic transformation in experimental renal cancer.
  
  
  CONCLUSIONS
  Alterations of EGFR system and MAPKs' play a major role in the development and progression of RCC. In the present study, the blockade of the Fe-NTA promoted EGFR signaling and sustained ERK activity with β-sitosterol leads to impede tumor promotion and maintenance.Rats which are pre-treated with 20 mg/kg bw of β-sitosterol significantly reduced the elevated expression of p-p38 MAPK, p-JNK, p-ERK, c-fos and c-jun in carcinogen induced rats, which suggest that β-sitosterol might protect renal tissue from neoplastic transformation. The interaction of β-sitosterol with the ATP binding site of ERK-2 by molecular docking studies also validates the inhibitory effect of β-sitosterol on ERK-2. The results of the present study reveal that β-sitosterol inhibit oncogenic MAPK signaling, to abrogate hyper cell proliferation, angiogenesis, and to induce apoptosis thereby prevent DEN and Fe-NTA induced renal carcinogenesis. Thus,β-sitosterol that modulates signal transduction pathways and their downstream events may serve as a potential cancer chemopreventive and therapeutic agent.Abbreviation used:AP-1: Activator protein-1,DEPC: Diethyl pyrocarbonate,EDTA: Ethylenediaminetetraacetic acid,EGFR: Endothelial growth factor receptor,ERK: Extracellular-signal regulating kinase,Fe-NTA: Ferric nitrilotriacetate,GAPDH: Glyceraldehyde-3-phosphate dehydrogenase,HBSS: Hank's balanced salt solution,JNK: c-Jun N-terminal kinase,MAPK: Mitogen-activated protein kinase,DEN: N-diethylnitrosamine,RCC: Renal cell carcinoma,SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis.
authors.affiliation: Department of Biochemistry and Biotechnology, Annamalai University, Tamil Nadu, India.
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Sharmila
authors.affiliation: Department of Biochemistry and Biotechnology, Annamalai University, Tamil Nadu, India.
authors.forename: Ganapathy
authors.initials: G
authors.lastname: Sindhu
keywords: DNA damage; endothelial growth factor receptor (EGFR); mitogen-activated protein kinases'; renal carcinogenesis; β-sitosterol