Potential Efficacy of Luteolin in Cutaneous Squamous Cell Carcinoma: A Combined In Vitro and In Vivo Study

Cutaneous squamous cell carcinoma (cSCC) is a common malignant skin tumor with invasive potential and risk of recurrence. This study investigated the anti-cSCC effects of luteolin in vitro and in vivo and explored the associated molecular mechanisms. The effects of luteolin on A431 cell viability were assessed by CCK-8 assay, and apoptosis was analyzed by Annexin V-FITC/propidium iodide (PI) double staining. qRT-PCR and Western blot analyses were performed to evaluate apoptosis-related factors and the EGFR/PI3K/AKT signaling pathway. Molecular docking was further conducted to explore the potential interactions of luteolin with EGFR/PI3K/AKT signaling-related proteins and apoptosis-associated proteins. In vivo, a two-stage skin carcinogenesis model induced by 7,12-dimethylbenz[a]anthracene (DMBA) and croton oil was used to evaluate the antitumor activity of luteolin. Luteolin significantly inhibited A431 cell viability and promoted apoptosis in a concentration-dependent manner. Moreover, luteolin increased Bax expression and decreased Bcl-2 expression at both the mRNA and protein levels. Mechanistically, luteolin suppressed the phosphorylation of EGFR, PI3K, and AKT. Molecular docking suggested that luteolin could interact with EGFR, PIK3CA, AKT, Bax, and Bcl-2, providing supportive in silico evidence for its potential modulation of EGFR/PI3K/AKT signaling and apoptosis-related proteins. In vivo, luteolin alleviated body weight loss, achieved a tumor nodule inhibition rate of 45.28%, significantly improved spleen and thymus indices (p < 0.05), and ameliorated histopathological damage in skin tissues. In addition, immunohistochemical analysis showed that luteolin reduced Ki-67 expression. These results indicate that luteolin exerts anti-cSCC effects in vitro and in vivo, possibly through modulation of the EGFR/PI3K/AKT signaling pathway and apoptosis-related proteins.