Blue Light Aminolevulinic Acid Photodynamic Therapy Downregulates Cell
Division and Proliferation Pathways in Cutaneous Squamous Cell Carcinoma
Abstract
5-Aminolevulinic (5-ALA) acid photodynamic therapy (PDT) is a treatment
for actinic keratosis and has been studied as a treatment for
non-invasive cutaneous squamous cell carcinoma (cSCC). PDT induces
apoptosis and necrosis in actinic keratosis and cSCC. 5-ALA blue light
PDT may modulate gene expression and pathways in surviving cells. In
this study, differential gene expression and pathway analysis of cSCC
and human dermal fibroblasts were compared before and after 5-ALA blue
light PDT using RNA-Sequencing. No genes were differentially expressed
after correcting for multiple testing (FDR <0.05). As a
result, transcription factor, gene enrichment, and pathway analysis were
performed with genes identified before multiple testing
(p<0.05). Pathways associated with proliferation and
carcinogenesis were downregulated. These findings using 5-ALA blue light
PDT are similar to previously published studies using
methyl-aminolevulinic and red light protocols, indicating that surviving
residual cells may undergo changes consistent with a less aggressive
cancerous phenotype.