The absence of Peroxiredoxin-1 in human pancreatic ductal adenocarcinoma (PDAC) markedly reduces cell survival and tumor growth when coupled with the inhibition of Ref-1 redox signaling.

Pancreatic ductal adenocarcinoma (PDAC) remains highly resistant to therapy, surviving despite hypoxia, oxidative stress, and nutrient deprivation. Redox effector factor-1 (Ref-1) regulates several oncogenic transcription factors (TFs) and is controlled by peroxiredoxins (PRDX). We investigated how Ref-1 inhibition by APX2014, combined with PRDX expression, affects pancreatic cancer cells from multiple patient lines. Silencing or CRISPR/Cas9 knockout of PRDX1-but not PRDX2-6-sensitized PDAC cell lines to APX2014 both in vitro and in vivo without affecting Ref-1's DNA repair function of apurinic/apyrimidinic endonuclease. The combination of PRDX1 loss and APX2014 treatment increased apoptosis and decreased TF activity (NF-κB, HIF-1α) and their downstream targets, TNFAIP2, Survivin, and CA9. A 3D co-culture with PRDX1-null tumor spheroids and cancer-associated fibroblasts (CAFs) showed that (i) Ref-1 inhibition impaired PRDX1-null tumor growth, and (ii) PRDX1 loss reduced CAF viability, highlighting redox crosstalk within the tumor microenvironment (TME). In a PDAC xenograft model, PRDX1-knockout tumors treated with APX2014 had smaller volumes, lighter weights, lower Ref-1, and decreased Ki-67, with improved animal survival. Patient microarrays indicated increased Ref-1 and PRDX1 levels versus normal tissue, emphasizing their clinical relevance. Overall, these data identify PRDX1 as a key factor for PDAC's susceptibility to Ref-1 blockade, suggesting dual targeting could disrupt TME redox signaling, limit tumor progression, and improve APX therapy. These findings support dual targeting of Ref-1 and PRDX1 as a promising therapeutic approach in PDAC and other redox-driven cancers.