title: l-Amino acid oxidase isolated from Calloselasma rhodostoma snake venom induces cytotoxicity and apoptosis in JAK2V617F-positive cell lines.
abstract: BACKGROUND
  Myeloproliferative neoplasms are Philadelphia chromosome-negative diseases characterized by hyperproliferation of mature myeloid cells, associated or not with the Janus kinase 2 tyrosine kinase mutation, JAK2V617F. As there is no curative therapy, researchers have been investigating new drugs to treat myeloproliferative neoplasms, including l-amino acid oxidase from Calloselasma rhodostoma snake venom (CR-LAAO), which is a toxin capable of eliciting apoptosis in several tumor cell lines.
  
  
  OBJECTIVE
  To evaluate the effects of l-amino acid oxidase from C. rhodostoma snake venom in the apoptotic machinery of JAK2-mutated cell lines.
  
  
  METHODS
  The HEL 92.1.7 and SET-2 cell lines were cultured with l-amino acid oxidase and catalase for 12h at 37°C in 5% carbon dioxide. The cell viability was assessed by the multi-table tournament method, the level of apoptosis was measured by ﬂow cytometry, and the expression of cysteine-dependent aspartate-specific proteases and cleaved Poly(ADP-ribose) polymerase were analyzed by Western blotting.
  
  
  RESULTS
  l-Amino acid oxidase from C. rhodostoma snake venom was cytotoxic to HEL 92.1.7 and SET-2 cells (50% inhibitory concentration=0.15μg/mL and 1.5μg/mL, respectively) and induced apoptosis in a concentration-dependent manner. Cell treatment with catalase mitigated the l-amino acid oxidase toxicity, indicating that hydrogen peroxide is a key component of its cytotoxic effect.The activated caspases 3 and 8 expression and cleaved PARP in HEL 92.1.7 and SET-2 cells confirmed the apoptosis activation by CR-LAAO.
  
  
  CONCLUSIONS
  l-Amino acid oxidase from C. rhodostoma snake venom is a potential antineoplastic agent against HEL 92.1.7 and SET-2 JAK2V617F-positive cells as it activates the extrinsic apoptosis pathway.
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Cristiane
authors.initials: C
authors.lastname: Tavares
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Thaís
authors.initials: T
authors.lastname: Maciel
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Sandra
authors.initials: S
authors.lastname: Burin
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Ambrósio
authors.affiliation: Universität Konstanz, Konstanz, Germany.
authors.forename: Sandro
authors.initials: S
authors.lastname: Ghisla
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Suely
authors.initials: S
authors.lastname: Sampaio
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil. Electronic address: castrofa@fcfrp.usp.br.
authors.forename: Fabíola
authors.initials: F
authors.lastname: Castro
keywords: Apoptosis; Calloselasma rhodostoma; Janus kinase 2 mutation; Myeloproliferative neoplasms; l-Amino acid oxidase