The tumor-stroma interaction contributes to the aggressive and resistance nature of pancreatic ductal adenocarcinoma (PDAC), leading to treatment failure. Cancer-associated fibroblasts (CAFs), a key cell type in the stroma, produce abundant extracellular matrix (ECM) and exhibit crosstalk with cancer cells inducing chemoresistance. In this study, we designed a cyclic peptide (cyAV3.3) targeting integrin α5 (ITGA5) to disrupt CAF-induced desmoplasia and crosstalk with cancer cells. In vitro, cyAV3.3 inhibited the differentiation of pancreatic stellate cells into CAFs and reduced ECM production. In 3D co-cultured human spheroid models, the peptide decreased markers of resistance (ABCG1, BCL2, CXCR4), stemness (WNT1, CD44) and ECM remodeling (COL1A1, MMP2/9, LOX) and enhanced gemcitabine efficacy. In vivo, radiolabeled cyAV3.3 exhibited high tumor accumulation and retention following parenteral injections in a co-injection xenograft tumor model. Intriguingly, combination of cyAV3.3 with gemcitabine resulted in improved therapeutic efficacy of gemcitabine in co-injection xenograft and genetically engineered LSL-KrasG¹²D/⁺ LSL-Trp53R¹⁷²H/⁺ Pdx1-Cre (KPC) PDAC models. These effects were attributed to reduced desmoplasia, vasculature compression and enhanced infiltration of cytotoxic T cells and apoptosis. This study presents a novel cyclic peptide inhibiting ITGA5-mediated tumor-stroma interaction and thereby reduce desmoplasia and resistance, ultimately enhancing chemotherapy efficacy in PDAC.

Pancreatic stellate cells  /  Cancer-associated fibroblasts  /  Pancreatic cancer  /  Tumor microenvironment  /  ITGA5  /  Fibronectin  /  Peptide  /  cyAV3.3