Sequential cryoablation enhances chemotherapeutic efficacy in pancreatic cancer by downregulating TGF-β mediated fibrosis in the sub-lethal zone

Cryoablation remodels desmoplastic TME in pancreatic cancer. • Sub-lethal freezing inhibits TGF-β/Smad signaling pathway. • Cryoablation preceding chemotherapy yields superior efficacy. • Disruption of fibrotic barriers sensitizes PDAC to chemotherapy. Cryoablation is effective for solid tumors but is often constrained by limited thermal efficiency and incomplete ablation. Conventional strategies prioritize expanding lethal isotherms to minimize the sub-lethal zone, a practice that increases the risk of collateral injury to adjacent critical structures. This study proposes a novel strategy utilizing the sub-lethal zone to remodel the tumor microenvironment for enhanced therapeutic efficacy. Using pancreatic cancer and stellate cell co-cultured spheroids and subcutaneous tumor models, we investigated fibrotic tumor microenvironment changes induced by the cryoablation sub-lethal zone combined with gemcitabine plus nab-paclitaxel. Results demonstrated that cryoablation significantly disrupted collagen structures and downregulated TGF-β1, p-Smad3, α-SMA, and Collagen I expression. This modulation is associated with the mitigation of fibrotic barriers, thereby potentially improving the accessibility of chemotherapy drugs within the sub-lethal zone. In vivo, cryoablation followed by chemotherapy yielded optimal efficacy compared to reverse sequencing or monotherapy, significantly inhibiting angiogenesis and promoting mitochondrial apoptosis via upregulated Bax and Caspase-3 levels. In conclusion, cryoablation functions as a potent tumor microenvironment remodeler. By downregulating TGF-β/Smad signaling, it sensitizes pancreatic ductal adenocarcinoma to subsequent chemotherapy, offering a superior sequential strategy to effectively inhibit the growth of residual tumor cells, offering an approach to improve local tumor control in PDAC.