Ru(II)-Photodynamic Therapy Suppresses Nonfunctioning Pituitary Adenoma Growth by Targeting PI3K/AKT/p53 Signaling

Aims Nonfunctioning pituitary adenomas (NFPAs) are a common intracranial tumor in clinical practice, and currently available treatments for NFPA include surgical resection and radiotherapy. However, this is due to the relatively high risk of recurrence and persistent side effects of these therapies. As a local treatment, photodynamic therapy (PDT) shows promise in solid tumors through spatiotemporally controlled cytotoxicity. The aim of this study was to investigate the mechanism of action of photosensitizer Ru2 in NFPA. Materials and methods [Ru(tpy)(tpy-Br)] (PF6)2 was synthesized from Ru(tpy)Cl3, and further synthesized into Ru2. Cell viability of Light+Ru2 or Dark+Ru2 was assayed using the CCK-8 assay and live-dead cell staining. RNA-seq of Light+Ru2-treated PDFS cells yielded differentially expressed genes. The expression of PI3K/ATK/P53 was detected using qPCR, Western blot. PI3K agonist 740Y-P and AKT agonist SC79 were added for further pathway validation. The effect of PDT on PDFS cell viability by 3D multicellular tumor spheroids (MCTSs) was evaluated. Key findings We untangle that Ru2-PDT specifically activates the p53 pathway and inhibits PI3K/AKT phosphorylation in PDFS cells. Under 595 nm illumination, Ru2 activates p53 and induces cell cycle arrest in the G0/G1 phase. Simultaneously, Ru2-PDT significantly suppressed the phosphorylation of the PI3K/AKT signaling pathway. Further investigation reveals that the PI3K/AKT agonist treatment partially inhibits p53 expression, alleviates Ru2-PDT-induced apoptosis, and reverses its inhibitory effects on PDFS cell migration and invasion. Significance This study, for the first time, elucidates the molecular mechanism of Ru2-PDT targeting the PI3K/AKT/p53 signaling axis, providing a theoretical basis for the clinical treatment of nonfunctioning pituitary adenomas.