Combination of 13 cis-retinoic acid and tolfenamic acid induces apoptosis and effectively inhibits high-risk neuroblastoma cell proliferation.

Abstract Chemotherapeutic regimens used for the treatment of Neuroblastoma (NB) cause long-term side effects in pediatric patients. NB arises in immature sympathetic nerve cells and primarily affects infants and children. A high rate of relapse in high-risk neuroblastoma (HRNB) necessitates the development of alternative strategies for effective treatment. This study investigated the efficacy of a small molecule, tolfenamic acid (TA), for enhancing the anti-proliferative effect of 13 cis -retinoic acid (RA) in HRNB cell lines. LA1-55n and SH-SY5Y cells were treated with TA (30 μM) or RA (20 μM) or both (optimized doses, derived from dose curves) for 48 h and tested the effect on cell viability, apoptosis and selected molecular markers (Sp1, survivin, AKT and ERK1/2). Cell viability and caspase activity were measured using the CellTiter-Glo and Caspase-Glo kits. The apoptotic cell population was determined by flow cytometry with Annexin-V staining. The expression of Sp1, survivin, AKT, ERK1/2 and c-PARP was evaluated by Western blots. The combination therapy of TA and RA resulted in significant inhibition of cell viability ( p