Avermectin induces toxic effects in insect nontarget cells involves DNA damage and its associated programmed cell death

Abstract

Avermectin (AVM), is widely applied in the fields of agriculture, possess activities against mites and insects. AVM is generally thought to keep the GABA-related chloride channels open in insect cells. However, AVM induces cytotoxicity in non-neural cells still ambiguous. Here we evaluate the cytotoxicity and other mode of action of AVM in Spodoptera frugiperda (Sf9) cells. Our results showed that AVM suppressed the activity of Sf9 cells and induced programmed cell death. DNA damage of Sf9 cells was detected by alkaline comet assay and PARP. The cleavage of poly ADP-ribose polymerase (PARP) and DNA double-strand breaks demonstrated AVM induced DNA damage in Sf9 cells. In addition, a series of established cytotoxicity tests were conducted to explore the mechanism of AVM toxicity in Sf9 cells. Typical apoptosis changes were occurred including increasing the expression of Bax/Bcl-2 and the activation of caspase-9/-3. Subsequently, Western blotting was used to detected autophagy related proteins including LC3, Beclin1 and p62. We found that AVM upregulated LC3, Beclin1 expression and downregulated p62 expressions. Moreover, we found that AVM induced autophagy may through AMPK/mTOR-mediated autophagy pathway. These results showed that AVM-induced DNA damage and programmed cell death in Sf9 cells.