The anti-cancer activity of clotam derivatives against high-risk neuroblastoma cell lines

Purpose: Neuroblastoma (NB) is the most common extracranial cancer diagnosed in infants and young children. High Risk Neuroblastoma (HRNB) is more aggressive with (40-50%) 5-year survival rates. Our laboratory is testing combination treatments using less toxic agents to sensitize HRNB cells to chemotherapy. The anti-cancer activity of a Non-Steroidal Anti-Inflammatory Drug, tolfenamic acid (TA), against HRNB cells has been shown. TA inhibits Specificity protein 1 (Sp1) and survivin, markers that are associated with aggressive cancer cell growth and resistance to chemo/radiation therapies. The objective of this study is to evaluate the effectiveness of TA and Copper-TA (Cu-TA) to inhibit HRNB cell growth alongside chemotherapy agent Vincristine (VCR). Methods: Anti-proliferative activity of TA or Cu-TA and/or (VCR) against HRNB cell lines, LA-155n and SMS-KCNR, and non-malignant cells, cardiomyocytes was evaluated using CellTiterGlo kit. Dose curves were plotted, and IC50 values were determined by Sigma-Plot software. The expression of Sp1 and survivin was determined by Western bot analysis. Results: When compared to TA, Cu-TA's IC50 values were about 50% less. TA and Cu-TA didn't affect cell viability of cardiomyocytes at IC50 doses. Cu-TA inhibited the expression of Sp1 and survivin in HRNB cells. The combination of Cu-TA and VCR showed higher efficiency for inhibiting HRNB cells. Conclusions: In conclusion, Cu-TA may effectively sensitize certain HRNB cells and induce the response of chemotherapy. Studies to understand the mechanism of action of Cu-TA are underway.