Mevalonate pathway promotes liver cancer by suppressing ferroptosis through CoQ10 production and selenocysteine-tRNA modification.

Hepatocellular carcinoma (HCC) is the prevalent form of primary liver cancer with a high rate of morbidity and death. Ferroptosis is a kind of regulatory cell death mode that depends on iron. Small ubiquitin-like modifier 2 (SUMO2) is linked to HCC progression; however, its role in ferroptosis within HCC remains unclear. Our goal was to evaluate the regulatory effects and molecular mechanisms of SUMO2 in HCC ferroptosis. SUMO2 was screened by bioinformatics analysis, and its expression was verified in HCC tissues. Stable SUMO2 knockdown and overexpression cell lines were created. The downstream target protein acyl-CoA synthetase long-chain family member 3 (ACSL3) of SUMO2 was screened to assessed the mechanism of SUMO2 regulating ferroptosis in HCC cells. In HCC tissues, SUMO2 expression was higher and linked to a worse prognosis for patients. SUMO2 overexpression reduced malondialdehyde content, prevented mitochondrial crest loss, and increased glutathione level under ferroptotic stimuli. Meanwhile, overexpression of SUMO2 lowered the expression of molecules that promote ferroptosis and raised the expression of molecules that prevent it. SUMO2 knockdown produced the opposite effects. Mechanistically, SUMO2 elevated ACSL3 protein level by inhibiting its entry into the ubiquitin–proteasome degradation pathway and enhanced its protein stability. The inhibitory effects of SUMO2 on ferroptosis in HCC cells were reversed by ACSL3 knockdown in SUMO2-overexpressing cells. In summary, SUMO2 binds to ACSL3, preventing its protein degradation, thereby increasing its protein stability and level, which in turn negatively regulates ferroptosis in HCC cells. These results point to interesting targets and therapeutic approaches for HCC.

The MicroRNA miR-139 Suppresses Metastasis and Progression of Hepatocellular Carcinoma by Down-regulating Rho-Kinase 2

Ferroptosis is a form of programmed cell death characterized by iron-dependent lipid peroxidation. Targeting ferroptosis is considered a novel strategy for cancer treatment. The benefits of using natural products to treat tumors have drawn more attention. Emodin, a natural anthraquinone derivative, has been shown to exert anti-tumor effects by promoting the generation and accumulation of reactive oxygen species (ROS), inducing apoptosis, autophagy, and cell cycle arrest. The molecular processes behind Emodin-mediated ferroptosis in hepatocellular carcinoma (HCC) cells were examined in our work. Emodin caused ferroptosis and suppressed growth in HCC cells in vitro. Emodin could increase ROS and lipid peroxidation, meanwhile decreasing glutathione (GSH), mitochondrial membrane potential, glutathione peroxidase 4 (GPX4), and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) expression, these effects could be reversed by Ferostatin-1 (Fer-1, an inhibitor of ferroptosis) and NFE2-like bZIP transcription factor 3 (NFE2L3). Mechanistically, Emodin enhances the expression of miR-4465, thereby suppressing NFE2L3 expression. The interaction between NFE2L3 and the HMGCR promoter is diminished, which subsequently downregulates GPX4 expression via the mevalonate pathway, leading to ferroptosis. Overexpression of NFE2L3 could alleviate Emodin-induced ferroptosis in HCC cells. Moreover, NFE2L3 knockout markedly reduced the expression of HMGCR and GPX4 in the Nfe2l3−/−mouse model. Emodin also caused ferroptosis and inhibited tumor development in a xenograft mice model. In conclusion, these results suggested that Emodin induces ferroptosis by inactivating the NFE2L3/HMGCR/GPX4 pathway in HCC cells. Emodin may be a promising candidate for the development of anticancer drugs and offers new strategies for cancer therapy.

BackgroundSorafenib is a commonly used first-line kinase-targeted drug for advanced hepatocellular carcinoma (HCC) patients suffering from limited efficacy. Emerging evidence indicates that sorafenib exerts anti-cancer activity through the induction of ferroptosis in HCC cells, but the underlying mechanism is still unclear.MethodsThe whole transcriptome sequencing and bioinformatics analysis were used to screen for target genes. The expression and subcellular localization of regulatory factor X1 (RFX1) were determined through immunohistochemistry, immunofluorescence, PCR and western blot analyses. The impact of RFX1 on HCC cell growth was assessed using CCK8, colony formation assays, cell death assays, and animal experiments. Glutathione measurement, iron assay and lipid peroxidation detection assays were performed to investigate ferroptosis of HCC cells. The regulatory mechanism of RFX1 in HCC was investigated by sgRFX1, co-IP, ChIP and luciferase experiments. Immunohistochemical and survival analyses were performed to examine the prognostic significance of RFX1 in HCC.ResultsIn this study, we found that RFX1 promote ferroptosis in HCC cells. Further, we showed that sorafenib induces cell death through RFX1-mediated ferroptosis in HCC cells. The enhancing effect of RFX1 on HCC cell ferroptosis is largely dependent on inhibition of cystine/glutamate antiporter (system Xc-) activity through the BECN-SLC7A11 axis, where RFX1 directly binds to the promoter region of BECN1 and upregulates BECN1 expression. In addition, a STAT3-RFX1-BECN1 signalling loop was found to promote RFX1 expression in HCC cells.ConclusionsOur study reveals a novel mechanism underlying sorafenib-induced HCC cell death.Graphical abstractSchematic representation of the role of RFX1 in the regulation of ferroptosis in human HCC cells

USP11 is involved in the sensitivity of liver cancer cells to ferroptosis and taxanes through the regulation of NRF2 ubiquitin-mediated degradation

Hepatocellular carcinoma (HCC) ranks among the most pervasive forms of cancer worldwide. In our study, we observed a notable overexpression of SNAPIN in human HCC tissues, which was linked closely to patient prognosis. Our experiments demonstrated that SNAPIN enhances the proliferative capacity of HCC cells. The knockdown of SNAPIN induces ferroptosis in HCC cells, whereas its overexpression partially resists the effects of ferroptosis inducers. As suggested by the above experimental findings, SNAPIN facilitates HCC progression by hindering HCC cell ferroptosis. Mechanistically, SNAPIN directly binds to KEAP1, facilitating its degradation via the autophago-lysosomal pathway, thereby undermining its stability. Consequently, NRF2 and its downstream target gene, GPX4, are upregulated. These alterations effectively mitigate lipid peroxidation damage, and ultimately impede HCC cell ferroptosis, potentially aiding in the progression of HCC. In conclusion, SNAPIN can negatively regulate the stability of KEAP1 protein, thereby initiating the NRF2/GPX4 pathway to hinder ferroptosis in HCC cells, ultimately facilitating HCC progression. Our results substantiate the pivotal function of SNAPIN in promoting HCC development, and this discovery is expected to provide an innovative therapeutic target for clinically managing HCC.

ZNF382 inhibits hepatocellular carcinoma (HCC) cell proliferation and motility and induces apoptosis by up-regulating SOX11

Objectives CDGSH iron sulfur domain 2 (CISD2) is essential to maintain iron (Fe) and reactive oxygen species (ROS) homeostasis, and ferroptosis suppressor protein 1 (FSP1) can protect cells from ferroptosis by inhibiting lipid peroxidation. Here, we investigate the role and potential mechanism of CISD2 and FSP1 in ferroptosis of hepatocellular carcinoma (HCC). Methods Human HCC cells were exposed to ferroptosis inducer Erastin, and the expression changes of CISD2 and FSP1 during ferroptosis were detected. Subsequently, we investigated the effect of overexpression of CISD2 on ferroptosis and FSP1 expression in HCC cells. Finally, we also investigated the effect of overexpression of FSP1 on ferroptosis in HCC cells. Results Erastin induced ferroptosis in hepatoma cells, and HepG2 cells were sensitive to Erastin. In addition, it was found that the expression of CISD2 was significantly upregulated and the expression of FSP1 was significantly downregulated in Erastin treated HepG2 cells. Subsequently, CISD2 was found to be highly expressed in HCC tissues, and overexpression of CISD2 reversed ferroptosis induced by Erastin in HepG2 cells and upregulated the expression of FSP1. Meanwhile, FSP1 showed a low expression level in HCC tissues and cells, and overexpression of FSP1 could reverse the ferroptosis induced by Erastin in HepG2 cells. Conclusion CISD2 and FSP1 are involved in the ferroptosis process of HCC induced by Erastin. CISD2 protects against the ferroptosis of HCC induced by Erastin by upregulating the expression of FSP1.

Ceruloplasmin suppresses ferroptosis by regulating iron homeostasis in hepatocellular carcinoma cells

BackgroundIncreasing evidence has demonstrated that long noncoding RNAs (lncRNAs) have regulatory functions in hepatocellular carcinoma (HCC). The link between lincSCRG1 and HCC remains unclear.MethodsTo explore the lincSCRG1 regulation axis, bioinformatics, RIP and luciferase reporter assay were performed. The expressions of lincSCRG1-miR26a-SKP2 were detected in HCC tissues and cell lines through qPCR and western blot. The functions of HCC cells were investigated through in vitro assays (MTT, colony formation, transwell and flow cytometry) and the inner effect of lincSCRG1-miR26a in vivo was evaluated by xenografts and liver metatstatic nude mice models.ResultsLincSCRG1 was found to be strongly elevated in human HCC tissues and cell lines. MiR26a and S phase kinase-related protein 2 (SKP2) were predicted as the target miRNA for lincSCRG1 and the target gene for miR26a with direct binding sites, respectively. LincSCRG1 was verified as a competing endogenous RNA (ceRNA) via negative regulation of miR26a and derepression of SKP2 in HCC cells. Both overexpression of lincSCRG1 (ov-lincSCRG1) and inhibition of miR26a (in-miR26a) obviously stimulated cellular viability, colony formation, migration and proliferation of S phase cells and also significantly increased the protein levels of cyclinD1, CDK4, MMP2/3/9, Vimentin, and N-cadherin or inhibited the protein level of E-cadherin of HCC cells, while knockdown of lincSCRG1 (sh-lincSCRG1) and upregulation of miR26a (mi-miR26a) had the opposite effects on HCC cells. Cotransfection of in-miR26a or overexpression of SKP2 (ov-SKP2) with sh-lincSCRG1 could rescue the anticancer functions of sh-lincSCRG1, including suppressing proliferation and migration of HCC cells. Additionally, sh-lincSCRG1 could effectively inhibit the growth of subcutaneous xenograft tumours and lung metastasis, while the anticancer effect of sh-lincSCRG1 could be reversed by cotransfection of in-miR26a.ConclusionsLincSCRG1 acts as a ceRNA of miR26a to restrict its ability to derepress SKP2, thereby inducing the proliferation and migration of HCC cells in vitro and in vivo. Depletion of lincSCRG1 could be used as a potential therapeutic approach in HCC.

The natural product auraptene can influence tumor cell proliferation and invasion, but its effect on hepatocellular carcinoma (HCC) cells is unknown. Here, we report that auraptene can exert anti-tumor effects in HCC cells via inhibition of cell proliferation and ferroptosis induction. Auraptene treatment induces total ROS and lipid ROS production in HCC cells to initiate ferroptosis. The cell death or cell growth inhibition of HCC cells induced by auraptene can be eliminated by the ROS scavenger NAC or GSH and ferroptosis inhibitor ferrostatin-1 or Deferoxamine Mesylate (DFO). Mechanistically, the key ferroptosis defense protein SLC7A11 is targeted for ubiquitin-proteasomal degradation by auraptene, resulting in ferroptosis of HCC cells. Importantly, low doses of auraptene can sensitize HCC cells to ferroptosis induced by RSL3 and cystine deprivation. These findings demonstrate a critical mechanism by which auraptene exhibits anti-HCC effects via ferroptosis induction and provides a possible therapeutic strategy for HCC by using auraptene or in combination with other ferroptosis inducers.

Tumor-Associated Macrophages Produce Interleukin 6 and Signal via STAT3 to Promote Expansion of Human Hepatocellular Carcinoma Stem Cells

Ferroptosis Suppressor Protein 1 Inhibition Promotes Tumor Ferroptosis and Anti-tumor Immune Responses in Liver Cancer

Hepatocellular carcinoma, HCC, is one of the commonest malignant cancers in human liver. The prognosis of HCC patients is extremely poor mainly because of late symptom presentation and absence of effective therapy. Liver is the metabolic engine that maintains the homeostasis of various nutrients; nevertheless, how the metabolic reprogramming of HCC cells benefits tumor progression remains largely unknown. Understanding the metabolic machinery of HCC is important for the development of new therapeutic approaches for HCC. Increased glucose intermediates through glycolysis and the pentose phosphate pathway (PPP) is a metabolic signature of cancer. The PPP works collaboratively with glycolysis to support rapid tumor growth by producing NADPH, the major antioxidant in the cells, and ribose-5-phosphate, the backbone of RNA. One of the key enzymes that connect PPP with glycolysis is the transketolase family (TK). The TK family comprises 3 members namely transketolase (TKT), TKT-like 1 (TKTL1) and TKTL2. Many studies have indicated that strong TKTL1 protein expression was correlated with invasive features and poor clinical outcome in other cancers. However, our transcriptome sequencing data from 16 pairs of human HCC and non-tumorous liver (NT) tissues revealed that (1) the TKT is the predominant TK member in the liver and HCC; (2) TKT, but not other TK family members, is overexpressed in HCC. In an expanded HCC cohort consisting of 60 human HCC cases, we confirmed that TKT is significantly overexpressed and is closely associated with aggressive HCC clinicopathological features including tumor microsatellite formation (P = 0.04), venous invasion (P = 0.01), and large tumor size (P = 0.04). Stable knockdown of TKT by various short hairpin RNA (shRNA) sequences in multiple HCC cell lines (MHCC97L, SMMC-7721, and BEL-7402) consistently suppressed cell growth, elevated intracellular ROS level (CM-H2DCFDA staining), and decreased glucose uptake (2-NBDG staining). In line with the in vitro observations, stable knockdown of TKT drastically impeded HCC growth in orthotropic and subcutaneous tumor models. More interestingly, pharmacological inhibition and genetic knockdown of TKT by oxythiamine (OT) and shRNA, respectively, sensitized HCC cells to the treatment of 2-deoxyglucose (2-DG), a glycolysis inhibitor. Inhibition of PPP and glycolysis by co-treatment of OT and 2-DG completely suppressed HCC growth. Taken together, our present data suggested that TKT overexpression strongly favors HCC cell growth in vitro and in vivo. Our data also showed that TKT is a critical component of the metabolic machinery of HCC and therefore an attractive therapeutic target. Citation Format: Mingjing Xu, Carmen Chak-Lui Wong, Irene Oi-Lin Ng. Transketolase (TKT) is a critical component of the metabolic machinery of hepatocellular carcinoma (HCC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2453. doi:10.1158/1538-7445.AM2014-2453

Primary hepatocellular carcinoma (HCC), a leading variant of primary liver cancer, holds significant global prevalence with strong implications for morbidity, mortality, and prognosis. Prevention and treatment paradigms are perpetually evolving in response to this malignancy. Ferroptosis, an iron and reactive oxygen species (ROS) dependant mode of cellular death, is catalyzed by an overabundance of lipid peroxidation, subsequently causing plasma membrane rupture. There is a unique interest in the relationship of ferroptosis with HCC development and progression, as compared to the interplay of apoptosis, autophagy, and necroptosis. Recent discoveries underscore the implications of ferroptosis in HCC evolution. Moreover, Traditional Chinese Medicine (TCM) and its respective active components display anti-HCC properties, a mechanism thought to be primarily attributed to the induction of ferroptosis in HCC cells. In support of preventive and therapeutic strategies for HCC, this manuscript provides a comprehensive review of the role of ferroptosis in HCC, its regulatory network, and the cutting-edge research focused on the treatment of HCC via ferroptosis modulation using TCM.