Yoshihiro Hayakawa

Dihydrocapsaicin Enhances Tumor Necrosis Factor-α-Induced Apoptosis and G1 Cell Cycle Arrest in Human Cervical Cancer Cells Through TAK1-Mediated NF-κB and EGFR Pathways

Dihydrocapsaicin (DHC), a prominent capsaicinoid derived from red chili peppers, has shown cytotoxic effects against various cancer cell types. However, its role in modulating cytokine-induced survival and apoptotic signaling in cancer cells remains unclear. In this study, we investigated the effects of DHC on tumor necrosis factor-α (TNF-α)-induced cell cycle arrest and apoptosis in HeLa human cervical cancer cells. Our results demonstrate that DHC significantly enhances TNF-α-induced G1 phase cell cycle arrest and apoptosis by targeting the transforming growth factor-β-activated kinase 1 (TAK1)-mediated prosurvival pathways. DHC inhibited the phosphorylation of TAK1 and downstream effectors including IKKα, NF-κB p65, MAPKs (p38, JNK, ERK), Akt, and EGFR, thereby disrupting key signaling networks that typically confer resistance to TNF-α-induced cytotoxicity. Additionally, DHC suppressed the TNF-α-induced phosphorylation of EGFR at Ser-1046/1047 and Thr-669, sites critical for survival signaling. Co-treatment with DHC and TNF-α led to enhanced apoptotic features, including increased PARP-1 cleavage. These findings suggest that DHC sensitizes cervical cancer cells to cytokine-induced cell death by interfering with TAK1/NF-κB and EGFR signaling axes. Our study positions DHC as a promising candidate for combination therapies aimed at overcoming resistance in cancers with aberrant inflammatory and survival signaling.