ROS/pH dual-sensitive emodin-chlorambucil co-loaded micelles enhance anti-tumor effect through combining oxidative damage and chemotherapy

The high level of reactive oxygen species (ROS) at the tumor site has been widely used in the tumor targeted delivery. However, the ROS stimulus-responsive vector itself is also a ROS consumer, and the consumption of endogenous ROS may not be sufficient to maintain sustained drug release. In this study, we designed and synthesized ROS/pH dual-sensitive polymer micelles for the co-delivery of emodin (EMD) and chlorambucil (CLB). The release of quinone methides (QM) can consume glutathione (GSH), on the one hand, it can enhance the chemotoxicity of phenylbutyrate nitrogen mustard, on the other hand, emodin can induce oxidative damage of tumor cells and maintain the sustained targeted release of drugs.

Enhanced Chemodynamic Therapy and Chemotherapy via Delivery of a Dual Threat ArtePt and Iodo-Click Reaction Mediated Glutathione Consumption

Cisplatin has been used as standard regimen for hepatocellular carcinoma (HCC), but its therapeutic efficacy is greatly limited by the drug resistance. Cisplatin alone cannot achieve an ideal therapeutic outcome. Herein, a dual threat hybrid artemisinin platinum (ArtePt) is synthesized to combine chemodynamic therapy (CDT) with chemotherapy. On the one hand, artesunate can react with intracellular ferrous ion to generate reactive oxygen species (ROS) via Fenton reaction for CDT. On the other hand, cisplatin can target DNA for chemotherapy. However, GSH in cancer cells can effectively consume free radicals and detoxify cisplatin simultaneously, which compromised the efficacy of CDT and chemotherapy. Hence, an amphiphilic polymer with an iodine atom in the side chain is designed and encapsulated ArtePt to form NP(ArtePt). This iodine containing polymer NP(ArtePt) can effectively deplete intracellular GSH via an Iodo-Click reaction, thereby enhancing the effect of CDT as well as chemotherapy. Thereafter, a patient-derived xenograft model of hepatic carcinoma (PDX^HCC ) is established to evaluate the therapeutic effect of NP(ArtePt), and a significant antitumor effect is achieved with NP(ArtePt). Overall, this study provides an effective strategy to combine CDT with chemotherapy to enhance the efficacy of cisplatin via Iodo-Click reaction, opening a new avenue for the cancer treatment.

Functionalized Tumor-Targeting Nanosheets Exhibiting Fe(II) Overloading and GSH Consumption for Ferroptosis Activation in Liver Tumor

Liver tumor is difficult to cure for its high degree of malignancy and rapid progression characteristics. Ferroptosis as a new model of inducing cell death is expected to break the treatment bottleneck of liver tumors. Here, a strategy to induce ferroptosis in HepG2 cells with acid-degradable tumor targeted nanosheets Cu-Hemin-PEG-Lactose acid (Cu-Hemin-PEG-LA) is proposed. After highly ingested by HepG2 cells, Cu-Hemin-PEG-LA nanosheets are degraded by weak acid and release Cu(II) and hemin, which consuming intracellular glutathione (GSH) content and increasing the expression of heme oxygenase 1 (HMOX1) protein, respectively. Furthermore, the expression of glutathione peroxidase 4 protein (GPX4) is down-regulated by consumption intracellular GSH content via converting GSH into glutathione oxidized (GSSG), which is named the classical mode. The intracellular Fe²⁺ content is overloaded by the significant up-regulation of HMOX1 expression, which is denoted as nonclassical mode. The synergistic effect of classical and nonclassical mode increased the intracellular lipid reactive oxide species, induced the occurrence of ferroptosis and up-regulated the expression of BH3 interacting domain death agonist (BID), apoptosis-inducing factor (AIF), and endonuclease G proteins (EndoG). The synergistic strategy demonstrate the excellent ferroptosis induction ability and antitumor efficacy in vivo, which provides great potential for the clinical transformation of ferroptosis.