Quantitative and Targeted Regulation of Ferroptosis in Bladder Cancer: Preclinical Study

The activation of ferroptosis, a cell death mechanism driven by excessive ferrous ions (Fe²⁺) and lipid peroxides, has emerged as a promising target for cancer treatment. However, in the case of quantitative regulation of target genes, it remains uncertain whether ferroptosis can be induced in bladder cancer (BCa) cells without affecting normal ones. We investigated this using an innovative CRISPR-dCas9 system to upregulate and downregulate the ferroptosis-related gene BECN1 and OTUB1, respectively. We identified two genes that can affect and promote ferroptosis-related pathways, analysing their expression in bladder tissue through The Cancer Genome Atlas. Our unique CRISPR-dCas9 technology, under the control of an hTERT promoter, selectively adjusted BECN1 and OTUB1 expression exclusively in cancer cells. RT-qPCR and western blotting demonstrated significant alterations in the expression of GPX4 and SLC7A11, proteins strongly associated with ferroptosis, in BCa cells, while normal bladder cells remained unaffected. We developed a quantitative model based on synthetic biology principles to describe the regulatory relationships between the ferroptosis-related genes BECN1 and OTUB1 and their downstream targets GPX4 and SLC7A11 in bladder cancer cells. The model establishes a direct proportional relationship between BECN1 upregulation and decreased GPX4 expression, and between OTUB1 downregulation and decreased SLC7A11 expression. In vitro experiments revealed reduced viability, proliferation, migration, and invasion in UMUC-3 and T24 BCa cells. Importantly, Fer-1 and DFO rescued the viability loss, and C11-BODIPY staining confirmed increased lipid ROS accumulation, supporting ferroptosis-associated cell death following BECN1/OTUB1 regulation. In vivo xenograft experiments showed that BECN1 upregulation or OTUB1 downregulation suppressed tumour growth. Tumour-tissue immunofluorescence further showed reduced GPX4 expression in BECN1-upregulated tumours and reduced SLC7A11 expression in OTUB1-downregulated tumours, supporting suppression of the GPX4/SLC7A11 ferroptosis-protective axis in vivo. The quantitative equation derived from our data suggests that the induction of ferroptosis in bladder cancer cells can be effectively modulated by these two genes, and the experimental results also indicate our system can modulate these two genes to affect the function of BCa cells without affecting the normal cells, offering a promising new direction for the development of targeted therapy for bladder cancer.