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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

CR-LAAO causes genotoxic damage in HepG2 tumor cells by oxidative stress

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Costa, Tassia R. [1] ; Amstalden, Martin K. [1] ; Ribeiro, Diego L. [2] ; Menaldo, Danilo L. [1] ; Sartim, Marco A. [1] ; Aissa, Alexandre F. [1] ; Antunes, Lusania M. G. [1] ; Sampaio, V, Suely
Total Authors: 8
[1] V, Univ Sao Paulo, Dept Clin Anal Toxicol & Food Sci, Sch Pharmaceut Sci Ribeirao Preto, Ave Cafe S-No, BR-14040903 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Dept Genet, Ribeirao Preto Med Sch, Ave Bandeirantes 3900, BR-14049900 Ribeirao Preto, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Toxicology; v. 404, p. 42-48, JUL 1 2018.
Web of Science Citations: 2

Snake venom L-amino acid oxidases (SV-LAAOs) are enzymes of great interest in research due to their many biological effects with therapeutic potential. CR-LAAO, an L-amino acid oxidase from Calloselasma rhodostoma snake venom, is a well described SV-LAAO with immunomodulatory, antiparasitic, microbicidal, and antitumor effects. In this study, we evaluated the genotoxic potential of this enzyme in human peripheral blood mononuclear cells (PBMC) and HepG2 tumor cells, as well as its interaction with these cells, its impact on the expression of DNA repair and antioxidant pathway genes, and reactive oxygen species (ROS)-induced intracellular production. Flow cytometry analysis of FITC-labelled CR-LAAO showed higher specificity of interaction with HepG2 cells than PBMC. Moreover, CR-LAAO significantly increased intracellular levels of ROS only in HepG2 tumor cells, as assessed by fluorescence. CR-LAAO also induced genotoxicity in HepG2 cells and PBMC after 4 h of stimulus, with DNA damages persisting in HepG2 cells after 24 h. To investigate the molecular basis underlying the genotoxicity attributed to CR-LAAO, we analyzed the expression profile (mRNA levels) of 44 genes involved in DNA repair and antioxidant pathways in HepG2 cells by RT2 Profiler polymerase chain reaction array. CR-LAAO altered the tumor cell expression of DNA repair genes, with two downregulated (XRCC4 and TOPBPI) and three upregulated (ERCC6, RAD52 and CDKN1) genes. In addition, two genes of the antioxidant pathway were upregulated (GPX3 and MPO), probably in an attempt to protect tumor cells from oxidative damage. In conclusion, our data suggest that CR-LAAO possesses higher binding affinity to HepG2 tumor cells than to PBMC, its genotoxic mechanism is possibly caused by the oxidative stress related to the production of H2O2 , and is also capable of modulating genes related to the DNA repair system and antioxidant pathways. (AU)

FAPESP's process: 15/00847-9 - Evaluation of genotoxic potential of an isolated L-amino acid oxidase from Calloselasma rhodostoma (CR-LAAO) venom on human cell lines
Grantee:Martin Krahenbuhl Amstalden
Support type: Scholarships in Brazil - Scientific Initiation
FAPESP's process: 15/00740-0 - Therapeutic potential evaluation of L-amino acid oxidases isolated from snake venoms as antitumor: genotoxicity and gene expression studies
Grantee:Tássia Rafaella Costa
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 11/23236-4 - Native and recombinant animal toxins: functional, structural and molecular analysis
Grantee:Suely Vilela
Support type: Research Projects - Thematic Grants