Antineoplastic Activity of Terpenes and Mannich Bases in Neuroblastoma SH-SY5Y Cells: Targeting PS3 Pathway

Abstract

Neuroblastoma is one of the most common childhood cancers arising from neural crest cells. It mainly affects sympathetic nervous system but can metastasize to other organs of the body. Therapeutic approaches for neuroblastoma range from multi modal therapy to surgery. Most effective treatment is combinational approach which includes induction of remission using chemotherapeutic drugs followed by consolidation phase using stem cell approach or radiotherapy and then maintenance phase to inhibit relapse of neuroblastoma. Still, with recent researches and advancement in therapy, mortality rate of neuroblastoma is high. Resistance and adverse effects of chemotherapeutic drugs limit their use. Keeping this in mind there is a need of newer molecules that can effectively work against neuroblastoma with less toxicity. Here we study novel molecules belonging to terpenoids and mannich bases for their potential antineoplastic activity against SH-SY5Y neuroblastoma cells. Inhibition of growth was assessed by using MTT assay which presented all the test compounds possessed ability to halt the growth of neuroblastoma cells. PGEA-AN, PGEA-4FAN, 3FB3FA8H and 3NBOABA8H showed IC50 dose of 12.5 µM, 8.5 µM, 3.5 µM and 5 µM respectively. The test compounds were compared to cisplatin which showed the IC50 of 17 µM. Apoptosis is considered more favorable mode of death in cancer cells, we checked for apoptotic involvement in growth inhibition of test compounds. Cells treated with test compounds showed morphological signs of apoptosis and nuclear condensation was evident on microscopy which was also shown by decrease in NAF of cells. Annexin V staining confirmed that apoptosis is induced by our test compounds. On molecular level, test compounds are found to enhance the expression of P53 gene. Increase in the level of BAX gene is also observed with no significant alteration of BCL2. This leads BAX/BCL2 ratio to shift towards pro-apoptotic BAX. Cleaved caspase 3 protein is also observed to be increased which might be consequence of BAX/BCL2 shift. Involvement of P53 pathway is augmented by increase in mitochondrial membrane permeability and reactive oxygen species generation. IX

Thus, based on the results of the present study, we conclude that the test compounds modulate P53 gene and induce apoptosis in SH-SY5Y neuroblastoma cell. Therefore, further exploration on these compounds at pre-clinical and clinical levels might give us opportunities to develop of novel potent anticancer agents for treatment against neuroblastoma.