Objective To investigate the mechanism by which crocin (CRO) induces immunogenic cell death (ICD) in nasopharyngeal carcinoma (NPC) cells via the CASP8/TNFAIP3 axis.
Methods CCK-8, Transwell, and TUNEL assays were used to detect the effects of CRO on CNE-1 viability, invasion, and apoptosis. Immunofluorescence staining and ELISA were performed to examine the expression levels of ICD markers (CRT, HMGB1, ATP, HSP70, and HSP90). Transwell co-culture combined with qRT-PCR was utilized to detect the expression of the DC surface markers CD80 and CD1a. Western blot analysis and Co-IP were employed to analyze CASP8–TNFAIP3 interaction. Functional rescue experiments applied siRNA knockdown and plasmid overexpression.
Results CRO dose-dependently inhibited CNE-1 viability and invasion; induced apoptosis; and promoted CRT exposure and HMGB1, ATP, HSP70, and HSP90 secretion (all P<0.05). DC-CNE-1 co-culture experiments showed that CRO reversed the inhibition of DC maturation by CNE-1, upregulating CD80 and CD1a expression (all P<0.05). CRO upregulated the expression of CASP8 and TNFAIP3 in CNE-1 cells; CASP8 knockdown reversed the anti-tumor effects of CRO and suppressed ICD and DC maturation; and TNFAIP3 overexpression reversed the phenotypic changes caused by CASP8 knockdown, including increased cell viability and invasion and decreased apoptosis and ICD marker levels (all P<0.05). Co-IP experiments confirmed CASP8–TNFAIP3 interactions.
Conclusion CRO induces ICD in NPC cells via CASP8/TNFAIP3 activation, promoting DC maturation and providing a novel target for NPC immunotherapy.
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