Prokaryotic Arsenate Reductase Enhances Arsenate Resistance In Mammalian Cells

It is known that arsenate reductase ArsC plays a crucial role in the process of arsenic detoxification in prokaryotes, but there is only one identified eukaryotic arsenate reductase in S. cerevisiae and no mammalian arsenate reductase has been identified so far. In the present study, mammalian HepG2cell lines were cultured and transfected with pEGFP-Nl-ArsC and pCI-neo-ArsC vectors. Twenty four hours after transfection, the expression and intracellular localization of pEGFP-Nl-ArsC were detected by laser confocal microscopy. For stably transfected cells, total RNA was extracted and the expression level of ArsC in HepG2cell lines were assayed by real-time quantification PCR. The viability of As3+-or As5+-exposed HepG2-pCI-ArsC cells were comparied to those of HepG2-pCI cells by MTT assay. The result of qRT-PCR revealed that ArsC derived from bacteria was expressed in HepG2cells and the expression was upregulated by As-induction. MTT analysis indicated that ArsC improved the viability of HepG2cells in As5+, but not in As3+. The formation of trivalent arsenic was also found increased in HepG2-pCI-ArsC cells. These results demonstrated that prokaryotic arsenic-resistant gene participated in eukaryotic expressing system and arsenic detoxification pathway. It would further help understand how ArsC functions during arsenic detoxification processes.