GPX4 transcriptionally promotes liver cancer metastasis via GRHL3/PTEN/PI3K/AKT axis.

Hepatocellular carcinoma (HCC) is among the most fatal types of malignancy, with a high prevalence of relapse and limited treatment options. As a critical regulator of ferroptosis and redox homeostasis, glutathione peroxidase 4 (GPX4) is commonly upregulated in HCC and is hypothesized to facilitate cancer metastasis, but this has not been fully explored in HCC. Here, we report that up-regulated GPX4 expression in HCC is strongly associated with tumor metastasis. FACS-based in vivo and in vitro analysis revealed that a cell subpopulation featuring lower cellular reactive oxygen species levels and ferroptosis resistance were involved in GPX4-mediated HCC metastasis. Mechanistically, GPX4 overexpressed in HCC tumor cells was enriched in the nucleus and transcriptionally silenced GRHL3 expression, thereby activating PTEN/PI3K/AKT signaling and promoting HCC metastasis. Functional studies demonstrated that GPX4 amino acids 110-145 are a binding site that interacts with the GRHL3 promoter. As AKT is a downstream target of GPX4, we combined the AKT inhibitor, AKT-IN3, with lenvatinib to effectively inhibit HCC tumor cell metastasis. Overall, these results indicate that the GPX4/GRHL3/PTEN/PI3K/AKT axis controls HCC cell metastasis and lenvatinib combined with AKT-IN3 represents a potential therapeutic strategy for patients with metastatic HCC.

A redox probe screens MTHFD1 as a determinant of gemcitabine chemoresistance in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a type of solid tumor derived from the bile duct epithelium that features universal gemcitabine resistance. Here, we utilized a gene-encoded ROS biosensor probe (HyPer3 probe) to sort subpopulations with different redox statuses from CCA cells. The isolated HyPer-low subpopulation CCA cells, which exhibited relatively lower cellular ROS levels, exhibited higher chemoresistance to gemcitabine than HyPer-high subpopulation CCA cells in vitro and in vivo. Mechanistically, increased expression of MTHFD1 was found in HyPer-low cells. Knocking down MTHFD1 in HyPer-low cells enhanced cellular ROS and restored sensitivity to gemcitabine. Furthermore, the MTHFD1 inhibitor antifolate compound methotrexate (MTX) increased cellular ROS, and combining gemcitabine with MTX effectively suppressed cholangiocarcinoma cell growth. In summary, the MTHFD1 level mediated the heterogeneous cellular redox status in CCA, which resulted in chemoresistance to gemcitabine. Our data suggest a novel strategy for CCA chemotherapy.

Calcipotriol Inhibits NLRP3 Signal Through YAP1 Activation to Alleviate Cholestatic Liver Injury and Fibrosis.

Cholestasis is common in multiple clinical circumstances. The NOD-like receptor protein 3 (NLRP3) inflammasome pathway has been demonstrated to play an important role in liver injury and fibrosis induced by cholestasis. We previously proved that MCC950, a selective NLRP3 inhibitor, alleviates liver fibrosis and injury in experimental liver cholestasis induced by bile-duct ligation (BDL) in mice. Herein, we investigate the role of calcipotriol, a potent vitamin D receptor agonist, in experimental liver cholestasis, test its therapeutic efficacy, and explore its potential protective mechanism. C57BL/6 mice were made to undergo BDL or fed the 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet to establish two classic cholestatic models. Calcipotriol was administered intraperitoneally to these mice daily. Serum makers of liver damage and integrity, liver histological changes, levels of liver pro-fibrotic markers, bile acid synthetases and transporters were measured in vivo. The underlying mechanism by which calcipotriol alleviates cholestatic liver injury and fibrosis was further investigated. The results of the current study demonstrated that calcipotriol supplement significantly alleviate cholestatic liver injury and fibrosis. Moreover, calcipotriol supplement markedly inhibited NLRP3 inflammasome pathway activation to alleviate liver injury and fibrosis in vivo and inhibit hepatic stellate cell (HSC) activation in vitro. In addition, VDR agonist calcipotriol exert inhibitory effect on NLRP3 inflammasome activation through activating yes-associated protein 1 (YAP1). In conclusion, our findings proved that calcipotriol suppressed the NLRP3 signal by activating YAP1 to alleviate liver injury and retard fibrogenesis in cholestasis.