Ginsenoside compound K induces ferroptosis via the FOXO pathway in liver cancer cells.

Liver cancer is a common malignant tumor worldwide, traditional Chinese medicine is one of the treatment measures for liver cancer because of its good anti-tumor effects and fewer toxic side effects. Ginsenoside CK (CK) is an active component of ginseng. This study explored the mechanism by which CK induced ferroptosis in liver cancer cells. We found that CK inhibited the proliferation of HepG2 and SK-Hep-1 cells, induced ferroptosis of cells. Ferrostatin-1, an ferroptosis inhibitor, was used to verify the role of CK in inducing ferroptosis of liver cancer cells. Network pharmacological analysis identified the FOXO pathway as a potential mechanism of CK, and western blot showed that CK inhibited p-FOXO1. In cells treated with the FOXO1 inhibitor AS1842856, further verify the involvement of the FOXO pathway in regulating CK-induced ferroptosis in HepG2 and SK-Hep-1 cells. A HepG2 cell-transplanted tumor model was established in nude mice, and CK inhibited the growth of transplanted tumors in nude mice, p-FOXO1 was decreased in tumor tissues, and SLC7A11 and GPX4 expressions were also down-regulated after CK treatment. These findings suggested that CK induces ferroptosis in liver cancer cells by inhibiting FOXO1 phosphorylation and activating the FOXO signaling pathway, thus playing an antitumor role.

Biomimetic Responsive Nanoconverters with Immune Checkpoint Blockade Plus Antiangiogenesis for Advanced Hepatocellular Carcinoma Treatment.

The first-line treatment for advanced hepatocellular carcinoma (HCC) combines immune checkpoint inhibitors and antiangiogenesis agents to prolong patient survival. Nonetheless, this approach has several limitations, including stringent inclusion criteria and suboptimal response rates that stem from the severe off-tumor side effects and the unfavorable pharmacodynamics and pharmacokinetics of different drugs delivered systemically. Herein, we propose a single-agent smart nanomedicine-based approach that mimics the therapeutic schedule in a targeted and biocompatible manner to elicit robust antitumor immunity in advanced HCC. Our strategy employed pH-responsive carriers, poly(ethylene glycol)-poly(ß-amino esters) amphiphilic block copolymer (PEG-PAEs), for delivering apatinib (an angiogenesis inhibitor), that were surface-coated with plasma membrane derived from engineered cells overexpressing PD-1 proteins (an immune checkpoint inhibitor to block PD-L1). In an advanced HCC mouse model with metastasis, these biomimetic responsive nanoconverters induced significant tumor regression (5/9), liver function recovery, and complete suppression of lung metastasis. Examination of the tumor microenvironment revealed an increased infiltration of immune effector cells (CD8+ and CD4+ T cells) and reduced immunosuppressive cells (myeloid-derived suppressor cells and T regulatory cells) in treated tumors. Importantly, our nanomedicine selectively accumulated in both small and large HCC occupying >50% of the liver volume to exert therapeutic effects with minimal systemic side effects. Overall, these findings highlight the potential of such multifunctional nanoconverters to effectively reshape the tumor microenvironment for advanced HCC treatment.

A target-triggered fluorescence-SERS dual-signal nano-system for real-time imaging of intracellular telomerase activity.

Telomerase (TE) is a promising diagnostic and prognostic biomarker for many cancers. Quantification of TE activity in living cells is of great significance in biomedical and clinical research. Conventional fluorescence-based sensors for quantification of intracellular TE may suffer from problems of fast photobleaching and auto-fluorescence of some endogenous molecules, and hence are liable to produce false negative or positive results. To address this issue, a fluorescence-SERS dual-signal nano-system for real-time imaging of intracellular TE was designed by functionalizing a bimetallic Au@Ag nanostructure with 4-p-mercaptobenzoic acid (internal standard SERS tag) and a DNA hybrid complex consisted of a telomerase primer strand and its partially complimentary strand modified with Rhodamine 6G. The bimetallic Au@Ag nanostructure serves as an excellent SERS-enhancing and fluorescence-quenching substrate. Intracellular TE will trigger the extension of the primer strand and cause the shedding of Rhodamine 6G-modified complimentary strand from the nano-system through intramolecular DNA strand displacement, resulting in the recovery of the fluorescence of Rhodamine 6G and decrease in its SERS signal. Both the fluorescence of R6G and the ratio between the SERS signals of 4-p-mercaptobenzoic acid and Rhodamine 6G can be used for in situ imaging of intracellular TE. Experimental results showed that the proposed nano-system was featured with low background, excellent cell internalization efficiency, good biocompatibility, high sensitivity, good selectivity, and robustness to false positive results. It can be used to distinguish cancer cells from normal ones, identify different types of cancer cells, as well as perform absolute quantification of intracellular TE, which endows it with great potential in clinical diagnosis, target therapy and prognosis of cancer patients.

Telomerase-initiated three-dimensional DNAzyme motor for monitoring of telomerase activity in living cells.

Telomerase (TE) is recognized as a potential biomarker for early diagnosis, monitoring and treatment of cancer. At present, most of the methods for TE detection are only applicable to in vitro assays, and unsuitable for in vivo applications. Though a few intracellular probes have been reported to have good specificity for TE, they do not involve signal amplification, which hinders their applicability in scenarios requiring high sensitivity. It is rather challenging to develop highly sensitive biosensors for intracellular TE detection due to the difficulty in design TE probes with both high specificity and compatibility with signal amplification in living cells. Herein, a highly sensitive and selective three-dimensional DNAzyme motor for monitoring of TE activity in living cells was developed by innovatively integrating TE-mediated chain replacement reaction with a three-dimensional DNA walker. Specifically, the DNAzyme motor was constructed by assembling both DNAzyme substrates and swing arms made up of a hairpin-structured DNAzyme and a telomeric primer onto gold nanoparticles. TE in cells can activate the DNAzyme motor to carry out continuous chain replacement and substrate cutting reactions, and hence realize signal amplification in living cells. The DNAzyme motor was successfully utilized to monitor the dynamic changes of TE activity in four types of cells. Due to the advantages of simple synthesis, good biocompatibility and high sensitivity and specificity for TE, the proposed DNAzyme motor is expected to have great application potential in the early diagnosis of cancer.

AuNPs@MIL-101 (Cr) as a SERS-Active Substrate for Sensitive Detection of VOCs.

Surface-enhanced Raman scattering (SERS) is an important and powerful analytical technique in chemical and biochemical analyses. Metal-organic frameworks (MOFs) can effectively capture volatile organic compounds (VOCs) with high adsorption capacity and fast kinetics, and the local surface plasmon resonance characteristics of gold nanoparticles can quickly and effectively distinguish different VOCs by SERS. Combining both, we designed a novel SERS substrate based on embedding gold nanoparticles (AuNPs) within MIL-101(Cr) for the recognition of various VOCs in the gaseous phase. Occupying of AuNPs inside MIL-101(Cr) increased the micropore-specific surface area of AuNPs@MIL-101(Cr), which enabled AuNPs@MIL-101(Cr) to absorb more toluene molecules and consequently realized its high detection sensitivity. The detection limits for toluene, 4-ethylbenzaldehyde, and formaldehyde were down to 6, 5, and 75, ppm respectively. Moreover, this substrate could be used for detecting different VOCs simultaneously. Finally, we discussed the enhancement of AuNPs outside and inside MIL-101(Cr) on the Raman signal.

SERS-Active MIL-100(Fe) Sensory Array for Ultrasensitive and Multiplex Detection of VOCs.

The application of metal-organic frameworks (MOFs) as SERS-active platforms in multiplex volatile organic compounds (VOCs) detection is still unexplored. Herein, we demonstrate that MIL-100 (Fe) serves as an ideal SERS substrate for the detection of VOCs. The limit of detection (LOD) of MIL-100(Fe) for toluene sensing can reach 2.5 ppm, and can be even further decreased to 0.48 ppb level when "hot spots" in between Au nanoparticles are employed onto MIL-100 (Fe) substrate, resulting in an enhancement factor of 1010 . Additionally, we show that MIL-100(Fe) substrate has a unique "sensor array" property allowing multiplex VOCs detection, with great modifiability and expandability by doping with foreign metal elements. Finally, the MIL-100(Fe) platform is utilized to simultaneously detect the different gaseous indicators of lung cancer with a ppm detection limit, demonstrating its high potential for early diagnosis of lung cancer in vivo.