Background:
The use of animal venoms and their toxins as material sources for
biotechnological applications has received much attention from the
pharmaceutical industry. L-amino acid oxidases from snake venoms (SV-LAAOs)
have demonstrated innumerous biological effects and pharmacological
potential against different cancer types. Hepatocellular carcinoma has
increased worldwide, and the aberrant DNA methylation of liver cells is a
common mechanism to promote hepatic tumorigenesis. Moreover, tumor
microenvironment plays a major role in neoplastic transformation. To
elucidate the molecular mechanisms responsible for the cytotoxic effects of
SV-LAAO in human cancer cells, this study aimed to evaluate the cytotoxicity
and the alterations in DNA methylation profiler in the promoter regions of
cell-cycle genes induced by BjussuLAAO-II, an LAAO from
Bothrops
jaracussu
venom, in human hepatocellular carcinoma (HepG2)
cells in monoculture and co-culture with endothelial (HUVEC) cells.
Methods:
BjussuLAAO-II concentrations were 0.25, 0.50, 1.00 and 5.00 μg/mL. Cell
viability was assessed by MTT assay and DNA methylation of the promoter
regions of 22 cell-cycle genes by EpiTect Methyl II PCR array.
Results:
BjussuLAAO-II decreased the cell viability of HepG2 cells in monoculture at
all concentrations tested. In co-culture, 1.00 and 5.00 μg/mL induced
cytotoxicity (
p
< 0.05). BjussuLAAO-II increased the
methylation of
CCND1
and decreased the methylation of
CDKN1A
in monoculture and
GADD45A
in
both cell-culture models (
p
< 0.05).
Conclusion:
Data showed BjussuLAAO-II induced cytotoxicity and altered DNA methylation of
the promoter regions of cell-cycle genes in HepG2 cells in monoculture and
co-culture models. We suggested the analysis of DNA methylation profile of
GADD45A
as a potential biomarker of the cell cycle
effects of BjussuLAAO-II in cancer cells. The tumor microenvironment should
be considered to comprise part of biotechnological strategies during the
development of snake-toxin-based novel drugs.