Nano-Econazole Enhanced PD-L1 Checkpoint Blockade for Synergistic Antitumor Immunotherapy against Pancreatic Ductal Adenocarcinoma.

ABSTRACT

Insufficienct T lymphocyte infiltration and unresponsiveness to immune checkpoint blockade therapy are still major difficulties for the clinical treatment of pancreatic ductal adenocarcinoma (PDAC). Although econazole has shown promise in inhibiting PDAC growth, its poor bioavailability and water solubility limit its potential as a clinical therapy for PDAC. Furthermore, the synergistic role of econazole and biliverdin in immune checkpoint blockade therapy in PDAC remains elusive and challenging. Herein, a chemo-phototherapy nanoplatform is designed by which econazole and biliverdin can be co-assembled (defined as FBE NPs), which significantly improve the poor water solubility of econazole and enhance the efficacy of PD-L1 checkpoint blockade therapy against PDAC. Mechanistically, econazole and biliverdin are directly released into the acidic cancer microenvironment, to activate immunogenic cell death via biliverdin-induced PTT/PDT and boost the immunotherapeutic response of PD-L1 blockade. In addition, econazole simultaneously enhances PD-L1 expression to sensitize anti-PD-L1 therapy, leading to suppression of distant tumors, long-term immune memory effects, improved dendritic cell maturation, and tumor infiltration of CD8+ T lymphocytes. The combined FBE NPs and α-PDL1 show synergistic antitumor efficacy. Collectively, FBE NPs show excellent biosafety and antitumor efficacy by combining chemo-phototherapy with PD-L1 blockade, which has promising potential in a precision medicine approach as a PDAC treatment strategy.