Nanomicelles for GLUT1-targeting hepatocellular carcinoma therapy based on NADPH depletion

Hepatocellular carcinoma (HCC) is a malignant tumor leading cancer-associated high mortality worldwide. Unfortunately, the most commonly used drug therapeutics not only lack of target ability and efficiency, but also exhibit severe systemic toxicity to normal tissues. Thus, effective and targeted nanodrug of HCC therapy is emerging as a more important issue. Here, we design and develop the novel nanomicelles, namely Mannose-polyethylene glycol 600-Nitroimidazole (Man-NIT). This micelle compound with high purity comprise two parts, which can self-assemble into nanoscale micelle. The outer shell is selected mannose as hydrophilic moiety, while the inner core is nitroimidazole as hydrophobic moiety. In the cell experiment, Man-NIT was more cellular uptake by HCCLM3 cells due to the mannose modification. Mannose as a kind of glucose transporter 1 (GLUT1) substrate, can specifically recognize and bind to over-expressed GLUT1 on carcinoma cytomembrane. The nitroimidazole moiety of Man-NIT was reduced by the over-expressed nitroreductase with reduced nicotinamide adenine dinucleotide phosphate (NADPH) as the cofactor, resulting in transient deletion of NADPH and glutathione (GSH). The increase of reactive oxygen species (ROS) in HCCLM3 cells disturbed the balance of redox, and finally caused the death of tumor cells. Additional in vivo experiment was conducted using twenty-four male BALB/c nude mice to build the tumor model. The results showed that nanomicelles were accumulated in the liver of mice. The tumor size and pathological features were obviously improved after nanomicelles treatment. It indicates that namomicelles have a tumor inhibition effect, especially Man-NIT, which may be a potential nanodrug of chemotherapeutics for HCC therapy.

Self-adaptive nanoassembly enabling turn-on hypoxia illumination and periphery/center closed-loop tumor eradication

Solid tumors are regarded as complex evolving systems rather than simple diseases. Self-adaptive synthetic therapeutics are required to cope with the challenges of entire tumors; however, limitations in accurate positioning and destruction of hypoxic niches seriously hinder complete tumor eradication. In this study, we engineer a molecular nanoassembly of sorafenib and a hypoxia-sensitive cyanine probe (CNO) to facilitate periphery/center synergistic cancer therapies. The self-adaptive nanoassembly with cascade drug release features not only effectively kills the peripheral tumor cells in normoxic rims but precisely illuminates hypoxic niches following the reduction of CNO by nitroreductase. More important, CNO is found to synergistically induce tumor ferroptosis with sorafenib via nicotinamide adenine dinucleotide phosphate (NADPH) depletion in hypoxic niches. As expected, the engineered nanoassembly demonstrates self-adaptive hypoxic illumination and periphery/center synergetic tumor eradication in colon and breast cancer BALB/c mouse xenograft models. This study advances turn-on hypoxia illumination and chemo-ferroptosis toward clinical applicability.

Effect of Malt-PEG-Abz@RSL3 micelles on HepG2 cells based on NADPH depletion and GPX4 inhibition in ferroptosis

Ferroptosis is a regulated cell death pathway which depends on iron. Ferroptosis can be induced by limiting intracellular glutathione (GSH) synthesis, or inhibiting the activity of GPX4, or increasing intracellular accumulation of PE-AA-OOH, all of which involve NADPH. Therefore, NADPH depletion, excessive PE-AA-OOH, and GPX4 deficiency are generally considered to be the main characteristics of ferroptosis. In this research, the novel self-assembly nanomicelles modified by maltose ligand (Malt-PEG-Abz@RSL3) with superior nano characteristics were designed and fabricated. Malt-PEG-Abz@RSL3 micelles achieved active targeted drug delivery due to the high expression of glucose transporter (GLUT) and high uptake by HepG2 cells. Maltose-polyethylene glycol broke to release RSL3 for inhibiting GPX4 activity when Malt-PEG-Abz@RSL3 micelles entered the cells. Meanwhile, key coenzyme NADPH that participated in synthesis of GSH and Trx(SH)₂ was depleted by azobenzene moiety, resulting in decreasing GSH and Trx(SH)₂, which dually induced ferroptosis in tumour cells and promoted cell apoptosis.