A hybrid nanopharmaceutical for specific-amplifying oxidative stress to initiate a cascade of catalytic therapy for pancreatic cancer

Abstract

Background Oxidative stress (OS) induced by an imbalance of oxidants and antioxidants is an important aspect in anticancer therapy, however, as an adaptive response, excessive glutathione (GSH) in the tumor microenvironment (TME) acts as an antioxidant against high reactive oxygen species (ROS) levels and prevents OS damage to maintain redox homoeostasis, suppressing the clinical efficacy of OS-induced anticancer therapies. Results A naturally occurring ROS-activating drug, galangin (GAL), is introduced into a Fenton-like catalyst (SiO2@MnO2) to form a TME stimulus-responsive hybrid nanopharmaceutical (SiO2-GAL@MnO2, denoted SG@M) for enhancing oxidative stress. Once exposed to TME, as MnO2 responds and consumes GSH, the released Mn2+ converts endogenous hydrogen peroxide (H2O2) into hydroxyl radicals (·OH), which together with the subsequent release of GAL from SiO2 increases ROS. The “overwhelming” ROS cause OS-mediated mitochondrial malfunction with a decrease in mitochondrial membrane potential (MMP), which releases cytochrome c from mitochondria, activates the Caspase 9/Caspase 3 apoptotic cascade pathway. Downregulation of JAK2 and STAT3 phosphorylation levels blocks the JAK2/STAT3 cell proliferation pathway, whereas downregulation of Cyclin B1 protein levels arrest the cell cycle in the G2/M phase. During 18 days of in vivo treatment observation, tumor growth inhibition was found to be 62.7%, inhibiting the progression of pancreatic cancer. Additionally, the O2 and Mn2+ released during this cascade catalytic effect improve ultrasound imaging (USI) and magnetic resonance imaging (MRI), respectively. Conclusion This hybrid nanopharmaceutical based on oxidative stress amplification provides a strategy for multifunctional integrated therapy of malignant tumors and image-visualized pharmaceutical delivery. Graphical Abstract

Trace elements in pancreatic cancer

“…introduced galangin into a Fenton‐like catalyst (SiO2@MnO2) to form hybrid nanomedical drugs in response to TME stimulation and confirmed in vivo and in vitro that the nanomedical drug can stimulate intracellular ROS concentrations and inhibit the JAK2/STAT3 cell proliferation pathway to exert APCA effects. 118 The present study showed that manganese plays an APCA role mainly by inducing ferroptosis and inhibiting the cell proliferation pathway, and additional studies are needed to uncover the APCA mechanism of manganese.…”