Isoliquiritigenin induces HMOX1 and GPX4-mediated ferroptosis in gallbladder cancer cells.

BACKGROUND: Gallbladder cancer (GBC) is the most common malignant tumor of biliary tract. Isoliquiritigenin (ISL) is a natural compound with chalcone structure extracted from the roots of licorice and other plants. Relevant studies have shown that ISL has a strong anti-tumor ability in various types of tumors. However, the research of ISL against GBC has not been reported, which needs to be further investigated. METHODS: The effects of ISL against GBC cells in vitro and in vivo were characterized by cytotoxicity test, RNA-sequencing, quantitative real-time polymerase chain reaction, reactive oxygen species (ROS) detection, lipid peroxidation detection, ferrous ion detection, glutathione disulphide/glutathione (GSSG/GSH) detection, lentivirus transfection, nude mice tumorigenesis experiment and immunohistochemistry. RESULTS: ISL significantly inhibited the proliferation of GBC cells in vitro . The results of transcriptome sequencing and bioinformatics analysis showed that ferroptosis was the main pathway of ISL inhibiting the proliferation of GBC, and HMOX1 and GPX4 were the key molecules of ISL-induced ferroptosis. Knockdown of HMOX1 or overexpression of GPX4 can reduce the sensitivity of GBC cells to ISL-induced ferroptosis and significantly restore the viability of GBC cells. Moreover, ISL significantly reversed the iron content, ROS level, lipid peroxidation level and GSSG/GSH ratio of GBC cells. Finally, ISL significantly inhibited the growth of GBC in vivo and regulated the ferroptosis of GBC by mediating HMOX1 and GPX4 . CONCLUSION: ISL induced ferroptosis in GBC mainly by activating p62-Keap1-Nrf2-HMOX1 signaling pathway and down-regulating GPX4 in vitro and in vivo . This evidence may provide a new direction for the treatment of GBC.

Nicotinamide N -methyltransferase promotes M2 macrophage polarization by IL6 and MDSC conversion by GM-CSF in gallbladder carcinoma.

BACKGROUND AND AIMS: Nicotinamide N -methyltransferase (NNMT), an enzyme responsible for the methylation of nicotinamide, is involved in many metabolic pathways in adipose tissue and the liver. However, the role of NNMT in editing the tumor immune microenvironment is not well understood. APPROACH AND RESULTS: Here, we identified that NNMT can promote IL6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression by decreasing the tri-methyl-histone H3 levels on the promoters of IL6 and CSF2 (encoding GM-CSF) and CCAAT/Enhancer Binding Protein, an essential transcription factor for IL6 expression, thus promoting differentiation of macrophages into M2 type tumor-associated macrophages and generation of myeloid-derived suppressor cells from peripheral blood mononuclear cells. Treatment of xenografted tumor models overexpressing NNMT gallbladder carcinoma (GBC) cells with the NNMT inhibitor JBSNF-000088 resulted in compromised tumor development and decreased expression levels of IL6, GM-CSF, tumor-associated macrophage marker CD206, and myeloid-derived suppressor cell marker CD33 but increased expression levels of CD8. In addition, elevated expression of NNMT in tumors of patients with GBC was correlated with increased expression levels of CD206 and CD33 but with decreased levels of CD8 and survival of patients. CONCLUSIONS: These data highlight the critical role of NNMT in GBC progression. Inhibition of NNMT by JBSNF-000088 is a potential molecular target for GBC immunotherapy.

Fibrinogen promotes gallbladder cancer cell metastasis and extravasation by inducing ICAM1 expression.

Fibrinogen plays an important role in tumor progression. Here, we explored the role of fibrinogen in gallbladder cancer (GBC) metastasis. The plasma fibrinogen level in M1 GBC patients was higher than in M0 GBC patients, indicating that fibrinogen may participate in GBC metastasis. Treatment of GBC cell lines with fibrinogen promoted metastasis and induced the expression of intercellular adhesion molecule 1 (ICAM1). ICAM1 overexpression promoted metastasis and knockdown inhibited it. The cell adhesion and transendothelial migration of GBC cells were enhanced by fibrinogen treatment and ICAM1 overexpression. In addition, the medium of fibrinogen-treated and overexpression-ICAM1 NOZ cells exhibited enhanced macrophages recruitment. This may work in concert to promote angiogenesis. Immunohistochemistry results on clinical specimens showed that higher fibrinogen levels, higher ICAM1 expression, higher blood vessel density, and higher macrophage levels were present simultaneously. Collectively, this study indicates fibrinogen promotes metastasis and extravasation by inducing ICAM1 expression to enhance tumor cell migration, cell adhesion, transendothelial migration and promote angiogenesis and increase vascular endothelial permeability.

Lithocholic acid inhibits gallbladder cancer proliferation through interfering glutaminase-mediated glutamine metabolism.

Lithocholic acid (LCA), one of the most common metabolic products of bile acids (BAs), is originally synthesized in the liver, stored in the gallbladder, and released to the intestine, where it assists absorption of lipid-soluble nutrients. LCA has recently emerged as a powerful reagent to inhibit tumorigenesis; however, the anti-tumor activity and molecular mechanisms of LCA in gallbladder cancer (GBC) remain poorly acknowledged. Here, we analyzed serum levels of LCA in human GBC and found that LCA was significantly downregulated in these patients, and reduced LCA levels were associated with poor clinical outcomes. Treatment of xenografts with LCA impeded tumor growth. Furthermore, LCA treatment in GBC cell lines decreased glutaminase (GLS) expression, glutamine (Gln) consumption, and GSH/GSSG and NADPH/NADP+ ratios, leading to cellular ferroptosis. In contrast, GLS overexpression in tumor cells fully restored GBC proliferation and decreased ROS imbalance, thus suppressing ferroptosis. Our findings reveal that LCA functions as a tumor-suppressive factor in GBC by downregulating GLS-mediated glutamine metabolism and subsequently inducing ferroptosis. This study may offer a new therapeutic strategy tailored to improve the treatment of GBC.

Spin-orbit-enabled sorting of optical flows in plasmonic nanocircuits.

On-chip controlling of photon spin is essential in developing future integrated nanophotonics with complex functionalities. Here we propose and demonstrate a robust spin-sorting nanocircuit, which consists of a spin-orbit coupler (i.e., combined nanoring and nanodisk) and an L-shaped dielectric-loaded surface plasmon (DLSPs) waveguide. The nanocircuit with optimized geometric parameters is shown to be capable of unidirectionally exciting and routing a DLSP mode along an independent waveguide. We found experimentally that the proposed device possesses an average insertion loss (extinction ratio) of 0.13 dB (14.8 dB) under complete circularly polarized incidence with opposite spin, which is in good agreement with theoretical calculations. The proposed spin-selective scheme may pave the way for applications in the manipulation of chirality with a flexible degree of freedom.

Rac GTPase activating protein 1 promotes gallbladder cancer via binding DNA ligase 3 to reduce apoptosis.

Rac GTPase activating protein 1 (RACGAP1) has been characterized in the pathogenesis and progression of several malignancies, however, little is known regarding its role in the development of gallbladder cancer (GBC). This investigation seeks to describe the role of RACGAP1 and its associated molecular mechanisms in GBC. It was found that RACGAP1 was highly expressed in human GBC tissues, which was associated to poorer overall survival (OS). Gene knockdown of RACGAP1 hindered tumor cell proliferation and survival both in vitro and in vivo. We further identified that RACGAP1 was involved in DNA repair through its binding with DNA ligase 3 (LIG3), a crucial component of the alternative-non-homologous end joining (Alt-NHEJ) pathway. RACGAP1 regulated LIG3 expression independent of RhoA activity. RACGAP1 knockdown resulted in LIG3-dependent repair dysfunction, accumulated DNA damage and Poly(ADP-ribosyl) modification (PARylation) enhancement, leading to increased apoptosis and suppressed cell growth. We conclude that RACGAP1 exerts a tumor-promoting role via binding LIG3 to reduce apoptosis and facilitate cell growth in GBC, pointing to RACGAP1 as a potential therapeutic target for GBC.

Single-cell RNA-sequencing atlas reveals an MDK-dependent immunosuppressive environment in ErbB pathway-mutated gallbladder cancer.

BACKGROUND & AIMS: Our previous genomic whole-exome sequencing (WES) data identified the key ErbB pathway mutations that play an essential role in regulating the malignancy of gallbladder cancer (GBC). Herein, we tested the hypothesis that individual cellular components of the tumor microenvironment (TME) in GBC function differentially to participate in ErbB pathway mutation-dependent tumor progression. METHODS: We engaged single-cell RNA-sequencing to reveal transcriptomic heterogeneity and intercellular crosstalk from 13 human GBCs and adjacent normal tissues. In addition, we performed WES analysis to reveal the genomic variations related to tumor malignancy. A variety of bulk RNA-sequencing, immunohistochemical staining, immunofluorescence staining and functional experiments were employed to study the difference between tissues with or without ErbB pathway mutations. RESULTS: We identified 16 cell types from a total of 114,927 cells, in which epithelial cells, M2 macrophages, and regulatory T cells were predominant in tumors with ErbB pathway mutations. Furthermore, epithelial cell subtype 1, 2 and 3 were mainly found in adenocarcinoma and subtype 4 was present in adenosquamous carcinoma. The tumors with ErbB pathway mutations harbored larger populations of epithelial cell subtype 1 and 2, and expressed higher levels of secreted midkine (MDK) than tumors without ErbB pathway mutations. Increased MDK resulted in an interaction with its receptor LRP1, which is expressed by tumor-infiltrating macrophages, and promoted immunosuppressive macrophage differentiation. Moreover, the crosstalk between macrophage-secreted CXCL10 and its receptor CXCR3 on regulatory T cells was induced in GBC with ErbB pathway mutations. Elevated MDK was correlated with poor overall survival in patients with GBC. CONCLUSIONS: This study has provided valuable insights into transcriptomic heterogeneity and the global cellular network in the TME, which coordinately functions to promote the progression of GBC with ErbB pathway mutations; thus, unveiling novel cellular and molecular targets for cancer therapy. LAY SUMMARY: We employed single-cell RNA-sequencing and functional assays to uncover the transcriptomic heterogeneity and intercellular crosstalk present in gallbladder cancer. We found that ErbB pathway mutations reduced anti-cancer immunity and led to cancer development. ErbB pathway mutations resulted in immunosuppressive macrophage differentiation and regulatory T cell activation, explaining the reduced anti-cancer immunity and worse overall survival observed in patients with these mutations.

SIRT3 inhibits gallbladder cancer by induction of AKT-dependent ferroptosis and blockade of epithelial-mesenchymal transition.

Dysfunction of Sirtuin 3 (SIRT3), an NAD+-dependent histone deacetylase, impairs varied mitochondrial metabolic pathways in human cancer. Here, we explored suppressive activity of SIRT3 in the progression of gallbladder cancer (GBC). Expression levels of SIRT3 in patients with GBC were lower than those in the adjacent normal tissue. In addition, decreased expression of SIRT3 in these patients was correlated with poor overall survival. Knockdown of SIRT3 gene in GBC cell lines induced mitochondrial respiration and energy metabolism, but inhibited oxidative ROS. Silence of SIRT3 gene also suppressed AKT-dependent ferroptosis, an iron-dependent and lipid peroxide-mediated cell death. Blockade of AKT activity in sh-SIRT3 cells induced ACSL4 expression that drives ferroptosis, and inhibited epithelial-mesenchymal (EMT) markers and invasive activity. In contrast, overexpression of SIRT3 led to the opposite effects on mitochondrial metabolism and EMT. Finally, transplantation of sh-SIRT3 cells in nude mice resulted in rapid tumor growth and larger tumors that expressed lower E-cadherin and lipid peroxide 4-hydroxynonenal (4-HNE) than those observed in control tumors. Collectively, our studies indicate that SIRT3 functions to inhibit AKT-dependent mitochondrial metabolism and EMT, leading to ferroptosis and tumor suppression.

Role of Sciellin in gallbladder cancer proliferation and formation of neutrophil extracellular traps.

Apart from primary tumor development and metastasis, cancer-associated thrombosis is the second cause of cancer death in solid tumor malignancy. However, the mechanistic insight into the development of gallbladder cancer (GBC) and cancer-associated thrombosis remains unclear. This study aimed to investigate the mechanistic role of Sciellin (SCEL) in GBC cell proliferation and the development of venous thromboembolism. The expression level of SCEL was determined by immunohistochemical staining. Roles of SCEL in gallbladder cancer cell were determined by molecular and cell biology methods. SCEL was markedly upregulated in GBC and associated with advanced TNM stages and a poor prognosis. Furthermore, SCEL interacted with EGFR and stabilized EGFR expression that activates downstream PI3K and Akt pathway, leading to cell proliferation. In addition, SCEL induces tumor cell IL-8 production that stimulates the formation of neutrophil extracellular traps (NETs), accelerating thromboembolism. In xenografts, SCEL-expressing GBCs developed larger tumors and thrombosis compared with control cells. The present results indicate that SCEL promotes GBC cell proliferation and induces NET-associated thrombosis, thus serving as a potential therapeutic target.

Anthrax toxin receptor 1/tumor endothelial marker 8 promotes gastric cancer progression through activation of the PI3K/AKT/mTOR signaling pathway.

Anthrax toxin receptor 1 (ANTXR1), a type I transmembrane protein, is one of the receptors that facilitates the entrance of anthrax toxin into cells. Previous studies have confirmed the pivotal role of ANTXR1 in progression and tumorigenesis of diverse cancer types. However, the biological function of ANTXR1 in gastric cancer (GC) is still unknown. The present study aimed to investigate the role of ANTXR1 in GC and illuminate the potential molecular mechanisms. Bioinformatics analysis found that ANTXR1 expression was significantly upregulated in GC tissue and its overexpression was associated with poor prognosis of GC patients. Moreover, we confirmed the upregulation of ANTXR1 in GC cell lines and GC tissue by quantitative PCR, western blot analysis, and immunohistochemical analysis. Additionally, high protein expression level of ANTXR1 was positively associated with several clinicopathological parameters in GC patients. In our study, a series of in vitro and in vivo assays were undertaken through strategies of loss/gain-of-function and rescue assays. Consequently, our results indicated that ANTXR1 induced proliferation, cell cycle progression, invasion and migration, and tumorigenicity and induced suppressed apoptosis in GC. Mechanistic investigation indicated that ANTXR1 exerted its promoting effects on GC through activation of the PI3K/AKT/mTOR signaling pathway. In conclusion, our findings suggested that ANTXR1 plays a crucial role in the development and progression of GC and could serve as a novel prognostic biomarker and potential therapeutic target for GC.