Comparative Transcriptomic Analysis Unveils Divergent Effects of FLASH Versus Conventional Irradiation on Skin Cells.

Objectives: FLASH radiotherapy is garnering attention for its capacity to diminish skin toxicity without compromising tumoricidal efficacy, presenting a stark contrast to conventional (CONV) radiotherapy. Despite its promise, the underlying molecular mechanisms of FLASH irradiation (FLASH-IR) on skin are not yet fully elucidated.

Methods: This study investigated the transcriptomic responses of human foreskin fibroblast cells (HFF-1) via the FLASH-IR or CONV irradiation (CONV-IR), employing the next-generation RNA sequencing (RNA-seq) to capture the gene expression profiles. Our comparative analysis aimed to dissect the cellular and molecular pathways influenced by these two irradiation methods.

Results: We identified a spectrum of differentially expressed genes (DEGs), signaling pathways, and transcriptional networks that were either shared or divergent between FLASH-IR and CONV-IR. Particularly, transcription factor NR4A1 showed significant upregulation in response to FLASH-IR, while chromatin stability factor ELF3 was markedly downregulated following CONV-IR. The top 10 up-regulated DEGs were subjected to qPCR validation, confirming their differential expression in response to FLASH-IR and CONV-IR.

Conclusion: Collectively, our findings delineate unique regulatory landscapes of FLASH-IR and CONV-IR on skin cells, corroborating established effects and shedding new light on the molecular interplay within the context of ultra-high dose radiation.