Exposure to TDCPP does not significantly affect cell viability until at concentration >68 μg/mL. HCECs show a 16% cell viability loss after exposing to 136 μg/mL TDCPP. Moreover, TDCPP induces a sharp decrease in viable cells (87%) after exposing to ≥272 μg/mL TDCPP. Based on cell viability, the LC
50
value for TDCPP is 202 μg/mL using a nonlinear regression. Compare to controls, TDCPP-exposed cells exhibit a concentration-dependent increase in apoptosis. Anti-apoptotic Bcl-2 protein expression is increased to 1.4 fold after exposing to 2 μg/mL TDCPP, 1.2-folds at 20 μg/mL but dynamically decreased to 0.4 fold at 200 μg/mL compare to control. The caspase-3 activity is increased to 2.1 folds of the control at 200 μg/mL TDCPP. TDCPP inhibits cell growth at lower concentrations (IC
50
of 27 μM), while cell viability and toxicity are affected at higher concentrations (IC
50
of 171 μM and 168 μM, respectively).
