Montmorillonite‐loaded magnesium alloy with photothermal and drug‐enhanced anti‐tumor and regulation of immune microenvironment for SVCS interventional therapy

Abstract

Abstract Superior vena cava syndrome (SVCS) caused by lung cancer accounts for 75% of patients with SVCS, which is one of the common complications of tumors. Interventional therapy is currently the most effective approach to relieve obstruction, but existing stents cannot inhibit or eliminate tumors, requiring postoperative radiotherapy and chemotherapy that may lead to secondary obstruction. Based on the characteristics of the tumor microenvironment and the interlayer ion replaceable properties of the layered material‐montmorillonite (MMT), the composite coating (MMT/Em/PDA) of emodin (Em)‐loaded MMT and dopamine was constructed on the magnesium alloy by liquid phase ion exchange technology and hydrothermal technology. The in vitro and in vivo results showed that the modified samples showed excellent corrosion resistance, the drug loading through adsorption and complexation with Zn 2+ between MMT layers, and the drug‐loaded samples possessed good pH and near‐infrared response‐controlled release drug performances. The MMT/Em/PDA sample exhibited an excellent photothermal conversion performance. Photothermal (PTT) synergistic drug therapy of samples could significantly promote the production of ROS in lung cancer cells damage mitochondria, and further inhibit cell adhesion, proliferation, and invasion by down‐regulating PI3K‐AKT and EMT signaling pathways, thereby causing tumor cell death. Furthermore, the multimodal therapies of samples promoted the repolarization of tumor‐associated macrophages into the M1 phenotype to re‐activate tumor immunity through activating the AKT‐NF‐κB signaling pathway. In normal tissues, they can significantly promote the M2 phenotype polarization to promote vascular tissue repair by inhibiting the AKT‐NF‐κB signaling pathway. This work helps to provide a new insight into designing the modified magnesium alloy.