KDM6A deficiency promotes 5-aminolevulinic acid-mediated photodynamic therapy resistance in bladder cancer by suppressing ROS accumulation.

BACKGROUND

Non-muscle invasive bladder cancer (NMIBC) frequently recurs after transurethral resection of bladder tumors, necessitating a novel therapeutic approach. 5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) has emerged as a minimally invasive therapeutic approach; however, its long-term efficacy remains limited, and the mechanisms underlying ALA-PDT resistance are unclear. Lysine-specific demethylase (KDM) 6A, a tumor suppressor frequently mutated in NMIBC, has been implicated in cancer stemness and therapy resistance.

OBJECTIVE

This study aimed to investigate the role of KDM6A deficiency in modulating ALA-PDT efficacy in bladder cancer.

METHODS

KDM6A-knockout (KO) bladder cancer cell lines were established using CRISPR/Cas9-based gene editing. Cancer stemness was evaluated via sphere formation assays and expression of stem cell markers, while the cytotoxic effects of ALA-PDT were assessed through cell viability analysis. Protoporphyrin IX (PpIX) accumulation and reactive oxygen species (ROS) generation were examined using fluorescence microscopy and flow cytometry.

RESULTS

KDM6A-KO cells exhibited significantly increased sphere-forming ability, enhanced stem cell marker expression, and greater resistance to ALA-PDT-induced cytotoxicity. Despite elevated PpIX accumulation in KDM6A-KO cells, ROS levels following ALA-PDT were significantly reduced. A negative correlation between KDM6A expression and ROS-scavenging enzymes expression, particularly SOD2 and GPX1, was confirmed both in public database analyses and in KDM6A-deficient cells.

CONCLUSIONS

These findings indicate that KDM6A deficiency promotes cancer stemness and confers resistance to ALA-PDT in bladder cancer cells by suppressing ROS generation despite increased PpIX levels. This study provides new insights into the role of KDM6A in ALA-PDT resistance and may contribute to developing novel therapeutic and diagnostic strategies for NMIBC.