Reduction-sensitive polymeric carrier for the targeted delivery of a quinazoline derivative for enhanced generation of reactive oxygen species against cancer.

Hepatocellular carcinoma (HCC) is one of the deadliest malignant tumors and the development of effective therapeutics against HCC is urgently needed. A novel quinazoline derivative 04NB-03 (Qd04) has been proved to be highly effective against HCC without obvious toxic side-effects. However, the poor water solubility and low bioavailability in vivo severely limit its clinical application. In addition, Qd04 kills tumor cells by inducing an accumulation of endogenous reactive oxygen species (ROS), which is highly impeded by the overexpression of glutathione (GSH) in tumor cells. Herein, we designed a disulfide cross-linked polyamino acid micelle to deliver Qd04 for HCC therapy. The disulfide linkage not only endowed a tumor-targeted delivery of Qd04 by responding to tumor cell GSH but also depleted GSH to achieve increased levels of ROS generation, which improved the therapeutic efficiency of Qd04. Both in vitro and in vivo results demonstrated that the synthesized nanodrug exerted good anti-hepatoma effects, which provided a potential application for HCC therapy in clinics.

A nanodrug simultaneously inhibits pancreatic stellate cell activation and regulatory T cell infiltration to promote the immunotherapy of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense extracellular matrix flooded with immune suppressive cells, resulting in extremely poor clinical response to immunotherapy. It has been revealed that the activation of pancreatic stellate cells (PSCs) makes considerable contributions to the immunological "cold" tumor microenvironment (TME). Herein, we developed a polyamino acid-based nanodrug incorporating the PSC activation inhibitor calcipotriol and anti-CXCL12 siRNA. The nanodrug was easily prepared with a small particle size and is capable of penetrating pancreatic tumors to inactivate PSCs and downregulate CXCL12. The in vivo results of orthotopic pancreatic tumor treatment demonstrated that codelivery of calcipotriol and anti-CXCL12 siRNA remodeled the PDAC TME with reduced extracellular matrix and decreased immunosuppressive T cells. Eventually, the infiltration of cytotoxic T cells was increased, thereby acting with immune checkpoint blockade (ICB) therapy for immunologically "cold" pancreatic tumors. In the present study, we propose a promising paradigm to improve the immunotherapy outcome of PDAC using nanodrugs that synchronously inhibit PSC activation and regulatory T-cell infiltration. STATEMENT OF SIGNIFICANCE: Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense extracellular matrix (ECM) that impedes the tumor infiltration of therapeutic agents and cytotoxic T lymphocytes, resulting in a poor clinical response to immunotherapy. In the present study, we proposed a promising approach for enhanced immunotherapy of pancreatic cancer. Specifically, a nanodrug incorporating calcipotriol and anti-CXCL12 siRNA was synthesized to synchronously inactivate matrix-producing pancreatic stellate cells and suppress the infiltration of regulatory T cells. The reduced ECM removed the pathological barrier, preventing nanodrug penetration and effector T-cell infiltration, leading to a conversion of the immunosuppressive "cold" microenvironment to a "hot" microenvironment, which eventually boosted the immunotherapy of anti-PD-1 antibodies in pancreatic cancer.