Anticancer activity of asiatic acid in cisplatin-resistant human neuroblastoma SH-SY5Y and its unaffected effect on human neural stem cells.

OBJECTIVE

To investigate the anticancer effects of asiatic acid (AA) and asiaticoside (AS) in cisplatin (Cis)-resistant neuroblastoma SH-SY5Y and neural stem cells derived from human stem cells from apical papilla (NSCs-hSCAPs).

METHODS

An MTT cell viability assay was performed to determine Cis toxicity and assess the cytotoxic effect of AA or AS on Cis-treated SH-SY5Y and the effect on NSCs-hSCAPs. Subsequently, the combination index (CI) was calculated to observe occurring interactions between the compound and Cis. For mechanistic exploration, flow cytometry using annexin V and PI staining and a caspase-3 activity assay were done to quantify apoptotic cell death. qRT-PCR was used to measure apoptotic and antioxidant mRNA levels. Additionally, the protein levels were analyzed by using the Western blot technique. Finally, to illustrate the putative interactions between the compound and its target, molecular docking was trialled.

RESULTS

MTT results revealed that AS did not affect both cells. However, 20 µM AA in combination with 2.5 µM Cis could significantly reduce SH-SY5Y cell viability with a CI value of 0.41, indicating their synergistic effect. Moreover, the effective concentration of AA did not affect Cis-treated NSCs-hSCAPs, suggesting its low toxicity. Considering SH-SY5Y, AA alone or its combination dramatically increased % apoptotic cells, which showed a minimal increment in Cis alone. Importantly, the combination treatment significantly increased caspase-3 activity. Mechanistically, BAX levels were elevated, whereas BCL2, SOD-1, and HO-1 levels were downregulated by AA alone or in combination. These results were also consistent with Western blot analysis. Interestingly, an inhibition of GSK3β was observed in the combination treatment, suggesting that these outcomes may be related.The molecular docking illustrated that AA interacted with GSK3β and BCL-2 through multiple residues, indicating their potential binding interactions.

CONCLUSION

AA and Cis treatment suppressed SH-SY5Y cell viability by enhancing apoptosis, reducing antioxidant gene expression, and potentially inhibiting GSK3β.