Cold atmospheric plasma prevents and treats oral squamous cell carcinoma via disruption of oncogenic pathways

Oral squamous cell carcinoma (OSCC), which develops through a multistep carcinogenic process, is a major threat to public health. Intercepting OSCC at its early stages or controlling established neoplasms continues to pose a significant clinical challenge. Our previous study demonstrated that cold atmospheric plasma (CAP) represents a promising therapeutic strategy for OSCC. In this study, we further investigated the preventive efficacy of CAP against oral carcinogenesis and characterized the molecular alterations associated with its counteracting effects, using murine cell lines and various in vivo models. In the 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis model, CAP irradiation markedly reduced epithelial thickening and suppressed the expression of tumor markers induced by 4-NQO, especially p63 and SOX2. In syngeneic orthotopic transplants of MOC-L1 and MTCQ1 murine OSCC cell lines, CAP treatment significantly inhibited tumor growth. Notably, residual tumor tissues after treatment remained in a growth-arrested but viable state for up to six weeks. These “resistance-like” tumors exhibited downregulation of oncogenic miRNAs, consistent with findings in human OSCC. Transcriptomic profiling and validation experiments revealed activation of pathways related to epithelial-mesenchymal transition, redox regulation, UV-responses and adipogenesis in these persistent tumors. Similarly, CAP-resistant cell subclones displayed molecular signatures paralleling those of resistant tumors, while targeted abrogation of key effector genes enhanced CAP sensitivity. In summary, CAP exerts a preventive effect in early oral neoplastic progression and suppresses OSCC tumorigenesis. Furthermore, combined inhibition of resistance-associated effectors can potentiate CAP-mediated tumor control. The findings provide mechanistic insight into CAP's preventive and therapeutic potential as a novel strategy for OSCC interception.