Transcription factor PRRX1-activated ANXA6 facilitates EGFR-PKCα complex formation and enhances cisplatin sensitivity in bladder cancer

Abstract

BackgroundTumor resistance to cisplatin represents a major clinical challenge, particularly in bladder cancer (BC). ANXA6 is a member of annexin family, and its role in cisplatin resistance remains unclear. This study explores ANXA6's role in promoting cisplatin sensitivity. MethodsBioinformatics analyses and clinical specimen verifications assessed the correlation between ANXA6 and cisplatin treatment. A series of assays, including CCK-8, clone formation assay, flow cytometry assays for reactive oxygen species (ROS) and apoptosis, and comet assays, were used to confirm ANXA6's role in enhancing cisplatin sensitivity and re-sensitizing resistant BC cells. Mass spectrometry, immunofluorescence, and co-immunoprecipitation experiments elucidated ANXA6's role in enhancing PKCα/EGFR complex formation and inhibiting the EGFR pathway. ChIP-PCR and dual-luciferase assays determined PRRX1's regulatory role on ANXA6 transcription. Finally, the impact of ANXA6 in vivo was evaluated using xenograft models. ResultsBioinformatics analyses showed a significant correlation between ANXA6 expression and cisplatin sensitivity. In vitro and in vivo experiments confirmed that ANXA6 was a new target for cisplatin treatment. ANXA6 overexpression not only enhanced cell viability inhibition, DNA damage and apoptosis caused by cisplatin, but also re-sensitized cisplatin-resistant cells. Mechanistically, ANXA6 promotes PKCα/EGFR complex formation, inhibiting EGFR phosphorylation and downstream AKT and ERK1/2. Moreover, PRRX1 was identified as a transcription factor promoting ANXA6 expression, thereby augmenting the cytotoxic effects of cisplatin. ConclusionOur study reveals the mechanism by which ANXA6 enhances cisplatin sensitivity and re-sensitizes resistant cells. The roles of PRRX1 and ANXA6 in cisplatin resistance offer new therapeutic targets to overcome cisplatin resistance in clinical practice.