title: The scorpion venom peptide BmKn2 induces apoptosis in cancerous but not in normal human oral cells.
abstract: OBJECTIVE
  This study aimed to investigate the mechanism of the induction of apoptosis of human oral cancer cells by the scorpion venom peptide BmKn2.
  
  
  METHODS
  Human oral squamous carcinoma cells (HSC4), mouth epidermoid carcinoma cells (KB), human normal gingival cells (HGC) and dental pulp cells (DPC) were treated with BmKn-2 peptide for 24h. Cell viability was determined by the MTT assay. Apoptosis was assessed using phase contrast microscopy, by propidium iodide (PI) staining to assess nuclear morphology and by Annexin V staining. Apoptotic signaling pathways were investigated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and Western blotting.
  
  
  RESULTS
  BmKn-2 showed potent cytotoxic effects towards both HSC4 and KB cells with the associated induction of apoptosis. The cells showed distinct morphological changes, nuclear disintegration and an increase in the number of Annexin V-positive cells. Interestingly, at concentrations which kill cancerous cells, BmKn-2 did not affect cell viability or mediate the induction of apoptosis in normal HGC or DPC. Induction of apoptosis by BmKn-2 in HSC4 and KB cells was associated with the activation of tumor suppress p53. Pro-apoptotic BAX expression was increased, whereas antiapoptotic BCL-2 expression was decreased in BmKn-2 exposed HSC4 and KB cells. BmKn-2 treated-oral cancer cells showed distinct upregulation of initiator caspase-9, with no effect on caspase-8 expression. Increased expression levels of executor caspases-3 and -7 were also found in treated cells for both oral cancers.
  
  
  CONCLUSIONS
  This study has suggested for the first time that BmKn-2 exerts selective cytotoxic effects on human oral cancer cells by inducting apoptosis via a p53-dependent intrinsic apoptotic pathway. BmKn-2 peptide originally derived from a natural source shows great promise as a candidate treatment for oral cancer, with minimal effects on healthy tissue.
authors: Department of Biotechnology, Faculty of Applied Science, King Mongkut's University of Technology of North Bangkok, Bangkok, 10140, Thailand.
authors: Saranya
authors: S
authors: Satitmanwiwat
authors: Reproductive Biology Group, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand.
authors: Chinarat
authors: C
authors: Changsangfa
authors: Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand.
authors: Anuson
authors: A
authors: Khanuengthong
authors: Reproductive Biology Group, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand.
authors: Kornkanok
authors: K
authors: Promthep
authors: Genome Institute, National Center for Genetic Engineering and Biotechnology, Pathumthani 12120, Thailand.
authors: Sittiruk
authors: S
authors: Roytrakul
authors: Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand.
authors: Teerakul
authors: T
authors: Arpornsuwan
authors: Reproductive Biology Group, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand.
authors: Kulnasan
authors: K
authors: Saikhun
authors: Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand. Electronic address: hathaitip.sri@mahidol.ac.th.
authors: Hathaitip
authors: H
authors: Sritanaudomchai
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D060829:Arthropod Proteins / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009062:Mouth Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012604:Scorpion Venoms / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D060829:Arthropod Proteins; C000614097:BmKn2 peptide, Mesobuthus martensii; D012604:Scorpion Venoms
keywords: Apoptosis; BmKn-2 peptide; Chemotherapeutic agent; Intrinsic apoptotic pathway; Oral cancer; Scorpion venom peptide