Investigation of the efficacy of doxorubicin combined with increased expression of caspase 9 on SH-SY5Y neuroblastoma cell line

SH-SY5Y is a neuroblastoma cell line which used as a cancer and neurodegenerative disorders model and its neuro-experimental studies. The different diseases cause by a defect in apoptosis pathway. Disruption of apoptotic proteins has an effect on the treatment process and response to drugs. In nerve cells, due to the high expression of apoptosis inhibitory proteins, the efficacy of drugs is low. Combination therapy is one of the developing treatment methods. The aim of this research is to evaluate the effectiveness of doxorubicin drug on apoptosis in SH-SY5Y cells under the conditions of high expression of caspase9. Caspase9 is a key enzyme in intrinsic apoptosis. First, cell viability was obtained through MTT assay under the different drug concentrations. Then, caspase9 gene was transfected in cells and affected by the concentration lower than IC50 of drug, and cell energy level and cell death were checked by different methods. ATP assay showed that the expression of caspase9 with drug lead to ATP decreases. Caspase3/7 activity indicated an increase in cell death by drug and caspase. Propidium staining to hoechst showed that the expression of caspase9 in combination with doxorubicin induce more death. To ensure the expression levels of protein that induces cell death, the amount of caspase3 protein was checked by western blotting, which showed a significant increase in combination of caspase9 and drug. Our findings showed that the induction of caspase9 expression intensifies the effect of drug and the combined treatment may be effective on the responsiveness of neuronal diseases.