Cells were collected by gentle scraping in PBS, washed once, and pelleted for subsequent R-loop profiling. A2780  cells were treated with cisplatin (25 µM) for 6 hours, , or vehicle control in biological replicates. Following treatment, cells were collected and washed  in PBS. Genome-wide mapping of R-loops was performed using the CUT&Tag-IT R-loop Assay Kit (Active Motif, 53167) according to the manufacturer's instructions, Sequencing libraries were prepared using the reagents provided in the kit, following the manufacturer's instructions. Libraries were amplified using Q5 polymerase. Final libraries were eluted in 20 µL of elution buffer, quantified by Qubit fluorometry, and assessed for quality by TapeStation D1000 High Sensitivity assay. Pooled libraries were sequenced on an Illumina platform to generate paired-end 150-bp reads, with a sequencing depth of ~50 million reads per sample.