Anti-proliferative and apoptosis-inducing effects of juvenile hormone analogue, fenoxycarb in the Sf21cell line

Abstract

The apprehension regarding the possible environmental effects of synthetic pesticides has led to the discovery and production of environmental friendly pesticides. Insect hormone mimics, mainly juvenile hormone analogues, like fenoxycarb have acquired attention due to their greater specificity than conventional broad-range insecticides as pest control agents. The study explored the effects of the insecticide juvenile hormone analogue (JHA), fenoxycarb, on the Sf21 cell line of Spodoptera frugiperda to illustrate the mode of action. Cytotoxicity assay was conducted at different concentrations of fenoxycarb ranging from 0.5 nM to 10 μM. The results showed the concentration-and time-dependent anti-proliferative effect of fenoxycarb. The median inhibitory concentration (IC50) was calculated as 28 nM at 48 h of exposure, and IC50 and IC25 concentrations were used for further cytotoxicity screening assays. Furthermore, the significant morphological changes of the cells after 48 h revealed the development of apoptotic bodies, membrane blebbing, cell size reduction, and irregular cell aggregation; additionally, enlarged cell spaces and widely diffused apoptotic bodies were observed after 72 h of insecticide exposure. In the confocal microscopic analysis of fenoxycarb treated cells, the nucleus was observed to condense and collapse into many fragments by Hoechst-33,342. Assessment of the relative potential of the cell cycle at two concentrations (IC50& IC25) reported the concentration-and time-dependent reduction of cells in the G1 phase with an upsurge in apoptotic cells. The percentage of cells that underwent apoptotic changes, such as loss of mitochondrial membrane potential (MMP), was strictly dependent on the fenoxycarb concentration and duration of exposure. The findings confirm the presence of fenoxycarb-mediated cell proliferation inhibition and apoptosis in Sf21 cell lines.