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

INTRODUCTION: Theobromine has been reported to exhibit anti-inflammatory and antioxidant effects. However, its molec-ular impact on cancer-associated signaling pathways remains poorly understood. This research was undertaken to eval-uate 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 An-nexin 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 sig-nificantly 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 NF-κB, p<0.001 for p-NF-κB, p<0.01 for IKK, and p<0.0001 for p-IKK).
DISCUSSION AND 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, natu-rally derived NF-κB modulator with potential applications as an adjuvant or chemopreventive agent in cancer therapy.

Keywords: Lung cancer, osteosarcoma, theobromine