Theobromine suppresses NF-κB signaling and promotes apoptosis in lung cancer and osteosarcoma cells

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TERZİ E., ÖZDEMİR SANCI T.

International Journal of Medical Biochemistry, cilt.9, sa.2, ss.124-132, 2026 (Scopus, TRDizin)

Özet

Objectives: Theobromine has been reported to exhibit anti-inflammatory and antioxidant effects. However, its molecular impact on cancer-associated signaling pathways remains poorly understood. This research was undertaken to evaluate the pro-apoptotic signaling effects of Theobromine on A549 lung cancer and Saos-2 osteosarcoma cells, focusing on modulation of the NF-κB signaling pathway. Methods: A549 and Saos-2 cells were exposed to Theobromine and the reference NF-κB inhibitor sulfasalazine at their IC₅₀ concentrations. Cell viability and IC₅₀ values were determined using the WST-1 assay. Apoptosis was quantified by Annexin V-FITC/PI staining, and total and phosphorylated NF-κB and IKK protein levels were quantified by flow cytometry. Results: Data were analyzed using one-way analysis of variance (ANOVA). In A549 lung cancer cells, Theobromine significantly induced apoptosis (p<0.001 for late apoptotic cells). A significant reduction in both total and phosphorylated NF-κB and IKK protein levels was observed compared with controls (p<0.05 for p-NF-κB and IKK, p<0.001 for p-IKK). In Saos-2 osteosarcoma cells, similarly increased apoptotic cell populations were observed (p<0.001 for early and late apoptotic cells). The treatment also resulted in reduced total and phosphorylated NF-κB and IKK levels (p<0.05 for NFκB, p<0.001 for p-NF-κB, p<0.01 for IKK, and p<0.0001 for p-IKK). Conclusion: This study provides the first evidence that Theobromine suppresses the NF-κB/IKK signaling pathway and promotes apoptosis in A549 and Saos-2 cancer cells. These findings suggest that Theobromine may act as a safe, naturally derived NF-κB modulator with potential applications as an adjuvant or chemopreventive agent in cancer therapy.