Electrosynthesis of Transition Metal Coordinated Polymers for Active and Stable Oxygen Evolution.

Transition metal coordination polymers (TM-CP) are promising inexpensive and flexible electrocatalysts for oxygen evolution reaction in water electrolysis, while their facile synthesis and controllable regulation remain challenging. Here we report an anodic oxidation-electrodeposition strategy for the growth of TM-CP (TM = Fe, Co, Ni, Cr, Mn; CP = polyaniline, polypyrrole) films on a variety of metal substrates that act as both catalyst supports and metal ion sources. An exemplified bimetallic NiFe-polypyrrole (NiFe-PPy) features superior mechanical stability in friction and exhibits high activity with long-term durability in alkaline seawater (over 2000 h) and anion exchange membrane electrolyzer devices at current density of 500 mA cm-2. Spectroscopic and microscopic analysis unravels the configurations with atomically distributed metal sites induced by d-π conjugation, which transforms into a mosaic structure with NiFe (oxy)hydroxides embedded in PPy matrix during oxygen evolution. The superior catalytic performance is ascribed to the anchoring effect of PPy that inhibits the metal dissolution, the strong substrate-to-catalyst interaction that ensures good adhesion, and the Fe/Ni-N coordination that modulates the electronic structures to facilitate the deprotonation of *OOH intermediate. This work provides a general strategy and mechanistic insight into building robust inorganic/polymer composite electrodes for oxygen electrocatalysis.

The potential role of CMC1 as an immunometabolic checkpoint in T cell immunity.

T cell immunity is critical for human defensive immune response. Exploring the key molecules during the process provides new targets for T cell-based immunotherapies. CMC1 is a mitochondrial electron transport chain (ETC) complex IV chaperon protein. By establishing in-vitro cell culture system and Cmc1 gene knock out mice, we evaluated the role of CMC1 in T cell activation and differentiation. The B16-OVA tumor model was used to test the possibility of targeting CMC1 for improving T cell anti-tumor immunity. We identified CMC1 as a positive regulator in CD8+T cells activation and terminal differentiation. Meanwhile, we found that CMC1 increasingly expressed in exhausted T (Tex) cells. Genetic lost of Cmc1 inhibits the development of CD8+T cell exhaustion in mice. Instead, deletion of Cmc1 in T cells prompts cells to differentiate into metabolically and functionally quiescent cells with increased memory-like features and tolerance to cell death upon repetitive or prolonged T cell receptor (TCR) stimulation. Further, the in-vitro mechanistic study revealed that environmental lactate enhances CMC1 expression by inducing USP7, mediated stabilization and de-ubiquitination of CMC1 protein, in which a mechanism we propose here that the lactate-enriched tumor microenvironment (TME) drives CD8+TILs dysfunction through CMC1 regulatory effects on T cells. Taken together, our study unraveled the novel role of CMC1 as a T cell regulator and its possibility to be utilized for anti-tumor immunotherapy.

PTEN deficiency potentiates HBV-associated liver cancer development through augmented GP73/GOLM1.

BACKGROUND: Although hepatitis B virus (HBV) infection is a major risk factor for hepatic cancer, the majority of HBV carriers do not develop this lethal disease. Additional molecular alterations are thus implicated in the process of liver tumorigenesis. Since phosphatase and tensin homolog (PTEN) is decreased in approximately half of liver cancers, we investigated the significance of PTEN deficiency in HBV-related hepatocarcinogenesis. METHODS: HBV-positive human liver cancer tissues were checked for PTEN expression. Transgenic HBV, Alb-Cre and Ptenfl/fl mice were inter-crossed to generate WT, HBV, Pten-/- and HBV; Pten-/- mice. Immunoblotting, histological analysis and qRT-PCR were used to study these livers. Gp73-/- mice were then mated with HBV; Pten-/- mice to illustrate the role of hepatic tumor biomarker golgi membrane protein 73 (GP73)/ golgi membrane protein 1 (GOLM1) in hepatic oncogenesis. RESULTS: Pten deletion and HBV transgene synergistically aggravated liver injury, inflammation, fibrosis and development of mixed hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). GP73 was augmented in HBV; Pten-/- livers. Knockout of GP73 blunted the synergistic effect of deficient Pten and transgenic HBV on liver injury, inflammation, fibrosis and cancer development. CONCLUSIONS: This mixed HCC-ICC mouse model mimics liver cancer patients harboring HBV infection and PTEN/AKT signaling pathway alteration. Targeting GP73 is a promising therapeutic strategy for cancer patients with HBV infection and PTEN alteration.

Deciphering the heterogeneity of neutrophil cells within circulation and the lung cancer microenvironment pre- and post-operation.

Neutrophils play a crucial role in the immune system within tumor microenvironment. At present, numerous studies have explored the changes of neutrophils' automatic killing effect and cellular communication with other immune cells under pathological conditions through single-cell sequencing. However, there remains a lack of definite conclusion about the identification criteria of neutrophil subgroups. Here, we collected tumor and para-carcinoma tissues, pre- and postoperative blood from patients with non-small cell lung cancer (NSCLC), and performed single-cell RNA (scRNA) sequencing to evaluate the distribution of neutrophil subgroups. We have developed a computational method of over expression rate (OER) to evaluate the specificity of neutrophil subgroups, in order to target gene panels with potential clinical application value. In addition, OER was used to evaluate specificity of neutrophil subsets in healthy people and patients with various diseases to further validate the feasibility of this evaluation system. As a result, we found the specificity of Neu_ c1_ IL1B and Neu_ c2_ cxcr4 (low) in postoperative blood has increased, while that of IL-7R + neutrophils has decreased, indicating that these groups of cells possibly differentiated or migrated to other subgroups in the state of lung cancer. In addition, seven gene panels (Neu_c3_CST7, RSAD2_Neu, S100A2/Pabpc1_Neu, ISG15/Ifit3_Neu, CD74_Neu, PTGS2/Actg1_Neu, SPP1_Neu) were high specific in all the four NSCLC-associated samples, meaning that changes in the percentage of these cell populations would have a high degree of confidence in assessing changes of disease status. In conclusion, combined consideration of the distribution characteristics of neutrophil subgroups could help evaluate the diagnosis and prognosis of NSCLC.

KAT8-catalyzed lactylation promotes eEF1A2-mediated protein synthesis and colorectal carcinogenesis.

Aberrant lysine lactylation (Kla) is associated with various diseases which are caused by excessive glycolysis metabolism. However, the regulatory molecules and downstream protein targets of Kla remain largely unclear. Here, we observed a global Kla abundance profile in colorectal cancer (CRC) that negatively correlates with prognosis. Among lactylated proteins detected in CRC, lactylation of eEF1A2K408 resulted in boosted translation elongation and enhanced protein synthesis which contributed to tumorigenesis. By screening eEF1A2 interacting proteins, we identified that KAT8, a lysine acetyltransferase that acted as a pan-Kla writer, was responsible for installing Kla on many protein substrates involving in diverse biological processes. Deletion of KAT8 inhibited CRC tumor growth, especially in a high-lactic tumor microenvironment. Therefore, the KAT8-eEF1A2 Kla axis is utilized to meet increased translational requirements for oncogenic adaptation. As a lactyltransferase, KAT8 may represent a potential therapeutic target for CRC.

Cancer-associated fibroblasts contributed to hepatocellular carcinoma recurrence and metastasis via CD36-mediated fatty-acid metabolic reprogramming.

Cancer-associated fibroblasts (CAFs) are the main components in the tumor microenvironment. Tumors activate fibroblasts from quiescent state into activated state by secreting cytokines, and activated CAFs may in turn promote tumor progression and metastasis. Therefore, studies targeting CAFs could enrich the therapeutic options for tumor treatment. In this study, we demonstrate that the content of lipid droplets and the expression of autophagosomes were higher in CAFs than in peri-tumor fibroblasts (PTFs), which was inhibited by 5-(tetradecyloxy)-2-furoic acid(TOFA). The expression of CD36 in CAFs was higher than that in PTFs at both mRNA and protein levels. Inhibition of CD36 activity using either the CD36 inhibitor SSO or siRNA had a significant negative impact on the proliferation and migration abilities of CAFs, which was associated with reduced levels of relevant activated genes (α-SMA, FAP, Vimentin) and cytokines (IL-6, TGF-ß and VEGF-α). SSO also inhibited HCC growth and tumorigenesis in nude mice orthotopically implanted with CAFs and HCC cells. Our data further show that CD36+CAFs affected the expression of PD-1 in CTLs leading to CTL exhaustion, and that patients with high CD36 expression in CAFs were correlated with shorter overall survival (OS). Together, our data demonstrate that CAFs were active in lipid metabolism with increased lipid content and lipophagy activity. CD36 may play a key role in the regulation of the biological behaviors of CAFs, which may influence the proliferation and migration of tumor cells by reprograming the lipid metabolism in tumor cells. Thus, CD36 could be an effective therapeutic target for the treatment of HCC.

Active AKT2 stimulation of SREBP1/SCD1-mediated lipid metabolism boosts hepatosteatosis and cancer.

Due to soared obesity population worldwide, hepatosteatosis is becoming a major risk factor for hepatocellular carcinoma (HCC). Undertaken molecular events during the progression of steatosis to liver cancer are thus under intensive investigation. In this study, we demonstrated that high-fat diet potentiated mouse liver AKT2. Hepatic AKT2 hyperactivation through gain-of-function mutation of Akt2 (Akt2E17K) caused spontaneous hepatosteatosis, injury, inflammation, fibrosis, and eventually HCC in mice. AKT2 activation also exacerbated lipopolysaccharide and D-galactosamine hydrochloride-induced injury/inflammation and N-Nitrosodiethylamine (DEN)-induced HCC. A positive correlation between AKT2 activity and SCD1 expression was observed in human HCC samples. Activated AKT2 enhanced the production of monounsaturated fatty acid which was dependent on SREBP1 upregulation of SCD1. Blockage of active SREBP1 and ablation of SCD1 reduced steatosis, inflammation, and tumor burden in DEN-treated Akt2E17K mice. Therefore, AKT2 activation is crucial for the development of steatosis-associated HCC which can be treated with blockage of AKT2-SREBP1-SCD1 signaling cascade.

Oncogenic ß-catenin-driven liver cancer is susceptible to methotrexate-mediated disruption of nucleotide synthesis.

BACKGROUND: Liver cancer is largely resistant to chemotherapy. This study aimed to identify the effective chemotherapeutics for ß-catenin-activated liver cancer which is caused by gain-of-function mutation of catenin beta 1 ( CTNNB1 ), the most frequently altered proto-oncogene in hepatic neoplasms. METHODS: Constitutive ß-catenin-activated mouse embryonic fibroblasts (MEFs) were established by deleting exon 3 ( ß-catenin Δ(ex3)/+ ), the most common mutation site in CTNNB1 gene. A screening of 12 widely used chemotherapy drugs was conducted for the ones that selectively inhibited ß-catenin Δ(ex3)/+ but not for wild-type MEFs. Untargeted metabolomics was carried out to examine the alterations of metabolites in nucleotide synthesis. The efficacy and selectivity of methotrexate (MTX) on ß-catenin-activated human liver cancer cells were determined in vitro . Immuno-deficient nude mice subcutaneously inoculated with ß-catenin wild-type or mutant liver cancer cells and hepatitis B virus ( HBV ); ß-catenin lox(ex3)/+ mice were used, respectively, to evaluate the efficacy of MTX in the treatment of ß-catenin mutant liver cancer. RESULTS: MTX was identified and validated as a preferential agent against the proliferation and tumor formation of ß-catenin-activated cells. Boosted nucleotide synthesis was the major metabolic aberration in ß-catenin-active cells, and this alteration was also the target of MTX. Moreover, MTX abrogated hepatocarcinogenesis of HBV ; ß-catenin lox(ex3)/+ mice, which stimulated concurrent Ctnnb1- activated mutation and HBV infection in liver cancer. CONCLUSION: MTX is a promising chemotherapeutic agent for ß-catenin hyperactive liver cancer. Since repurposing MTX has the advantages of lower risk, shorter timelines, and less investment in drug discovery and development, a clinical trial is warranted to test its efficacy in the treatment of ß-catenin mutant liver cancer.

Favoring CO Intermediate Stabilization and Protonation by Crown Ether for CO2 Electromethanation in Acidic Media.

The large-scale deployment of CO2 electroreduction is hampered by deficient carbon utilization in neutral and alkaline electrolytes due to CO2 loss into (bi)carbonates. Switching to acidic media mitigates carbonation, but suffers from low product selectivity because of hydrogen evolution. Here we report a crown ether decoration strategy on a Cu catalyst to enhance carbon utilization and selectivity of CO2 methanation under acidic conditions. Macrocyclic 18-Crown-6 is found to enrich potassium cations near the Cu electrode surface, simultaneously enhancing the interfacial electric field to stabilize the *CO intermediate and accelerate water dissociation to boost *CO protonation. Remarkably, the mixture of 18-Crown-6 and Cu nanoparticles affords a CH4 Faradaic efficiency of 51.2 % and a single pass carbon efficiency of 43.0 % toward CO2 electroreduction in electrolyte with pH=2. This study provides a facile strategy to promote CH4 selectivity and carbon utilization by modifying Cu catalysts with supramolecules.

Peripheral immune mapping and multi-omics analysis in Pd-1 inhibitor-induced myocarditis.

More immune-related adverse events (irAEs) have emerged along with increased immune checkpoint inhibitor (ICI) treatment. ICI-induced myocarditis is a rare type of irAE with early onset, rapid progression, and high mortality. Its specific pathophysiological mechanism is not fully understood. In total, 46 patients with tumors and 16 patients with ICI-induced myocarditis were included. We performed single-cell RNA sequencing on CD3 + T cells, flow cytometry, proteomics, and lipidomics to improve our understanding of the disease. First, we demonstrate the clinical features of patients with PD-1 inhibitor-induced myocarditis. We then identified 18 subsets of T cells using single-cell RNA sequencing and performed comparative analysis and further verification. The composition of T cells in the peripheral blood of patients has changed remarkably. Compared with non-irAE patients, effector T cells were increased in irAE patients, while naive T cells, γδ T cells, and mucosal-associated invariant T cell cluster cells were decreased. Besides, reduced γδ T cells characterized with effector functions, increased natural killer T cells with high levels of FCER1G in patients may suggest an association with disease development. Meanwhile, the peripheral inflammatory response was exacerbated in patients, accompanied by upregulation of exocytosis as well as increased levels of multiple lipids. We provide a comprehensive overview of the composition, gene profiles, and pathway signatures of CD3+ T cells driven by PD-1 inhibitor-induced myocarditis, as well as illustrate clinical features and multi-omic characteristics, providing a unique perspective on disease progression and therapy in clinical practice.

Enzyme activity- and chemometrics-assisted comprehensive two-dimensional liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry for the analysis of honeysuckle.

A unique and effective comprehensive two-dimensional liquid chromatography system was established and applied for the analysis of bioactive components in honeysuckle. Under the optimal conditions, Eclipse Plus C18 (2.1 × 100 mm, 3.5 µm, Agilent) and SB-C18 (4.6 × 50 mm, 1.8 µm, Agilent) columns were chosen for the first dimension (1D) and the second dimension (2D) separation. The optimal flow rates of 1D and 2D were 0.12 mL/min and 2.0 mL/min, respectively. Additionally, the proportion of organic solution was optimized to enhance orthogonality and integrated shift, and full gradient elution mode was adopted to improve chromatographic resolution. Furthermore, a total of 57 compounds were identified by molecular weight, retention time and collision cross-section value obtained from ion mobility mass spectrometry. Based on the data obtained from the principal component analysis, partial least squares discriminant analysis, and hierarchical cluster analysis, the categories of honeysuckle in different regions were significantly different. Moreover, the half maximal inhibitory concentration values of most samples were between 0.37 and 1.55 mg/mL, and most samples were potent α-glucosidase inhibitors, which is better for the evaluation of the quality of drugs from two aspects of substance content and activity.

The immune-metabolic crosstalk between CD3+C1q+TAM and CD8+T cells associated with relapse-free survival in HCC.

Introduction: Although multiple targeted treatments have appeared, hepatocellular carcinoma (HCC) is still one of the most common causes of cancer-related deaths. The immunosuppressive tumor microenvironment (TME) is a critical factor in the oncogenesis and progression of HCC. The emerging scRNA-seq makes it possible to explore the TME at a high resolution. This study was designed to reveal the immune-metabolic crosstalk between immune cells in HCC and provide novel strategies to regulate immunosuppressive TME. Method: In this study, we performed scRNA-seq on paired tumor and peri-tumor tissues of HCC. The composition and differentiation trajectory of the immune populations in TME were portrayed. Cellphone DB was utilized to calculate interactions between the identified clusters. Besides, flow cytometry, RT-PCR and seahorse experiments were implemented to explore potential metabolic and epigenetic mechanisms of the inter-cellular interaction. Result: A total of 19 immune cell clusters were identified and 7 were found closely related to HCC prognosis. Besides, differentiation trajectories of T cells were also presented. Moreover, a new population, CD3+C1q+ tumor-associated macrophages (TAM) were identified and found significantly interacted with CD8+ CCL4+T cells. Compared to the peri-tumor tissue, their interaction was attenuated in tumor. Additionally, the dynamic presence of this newly found cluster was also verified in the peripheral blood of patients with sepsis. Furthermore, we found that CD3+C1q+TAM affected T cell immunity through C1q signaling-induced metabolic and epigenetic reprogramming, thereby potentially affecting tumor prognosis. Conclusion: Our study revealed the interaction between CD3+C1q+TAM and CD8+ CCL4+T cells and may provide implications for tackling the immunosuppressive TME in HCC.

ß-catenin-IRP2-primed iron availability to mitochondrial metabolism is druggable for active ß-catenin-mediated cancer.

BACKGROUND: Although ß-catenin signaling cascade is frequently altered in human cancers, targeting this pathway has not been approved for cancer treatment. METHODS: High-throughput screening of an FDA-approved drug library was conducted to identify therapeutics that selectively inhibited the cells with activated ß-catenin. Efficacy of iron chelator and mitochondrial inhibitor was evaluated for suppression of cell proliferation and tumorigenesis. Cellular chelatable iron levels were measured to gain insight into the potential vulnerability of ß-catenin-activated cells to iron deprivation. Extracellular flux analysis of mitochondrial function was conducted to evaluate the downstream events of iron deprivation. Chromatin immunoprecipitation, real-time quantitative PCR and immunoblotting were performed to identify ß-catenin targets. Depletion of iron-regulatory protein 2 (IRP2), a key regulator of cellular iron homeostasis, was carried out to elucidate its significance in ß-catenin-activated cells. Online databases were analyzed for correlation between ß-catenin activity and IRP2-TfR1 axis in human cancers. RESULTS: Iron chelators were identified as selective inhibitors against ß-catenin-activated cells. Deferoxamine mesylate, an iron chelator, preferentially repressed ß-catenin-activated cell proliferation and tumor formation in mice. Mechanically, ß-catenin stimulated the transcription of IRP2 to increase labile iron level. Depletion of IRP2-sequered iron impaired ß-catenin-invigorated mitochondrial function. Moreover, mitochondrial inhibitor S-Gboxin selectively reduced ß-catenin-associated cell viability and tumor formation. CONCLUSIONS: ß-catenin/IRP2/iron stimulation of mitochondrial energetics is targetable vulnerability of ß-catenin-potentiated cancer.

A deficient MIF-CD74 signaling pathway may play an important role in immunotherapy-induced hyper-progressive disease.

BACKGROUND: With the advent of immune checkpoint inhibitors (ICIs) therapies, a major breakthrough has been made in cancer treatment. However, instead of good results, some patients experienced a deterioration of their disease. This unexpected result is termed as hyper-progressive disease (HPD). The biology of HPD is currently not fully understood. METHODS: Isolation of CD3+ cells from peripheral blood mononuclear cells (PBMC) in healthy control, tumor patients receiving immunotherapy with or without immunotherapy-induced HPD, then conducted single-cell RNA sequencing (scRNA-seq). RESULTS: By analyzing scRNA-seq data, we identified 15 cell clusters. We observed developed-exhausted CD4+ T cells and regulatory T cells (Tregs) increasingly enriched in HPD group. Meanwhile, some effector T cells were decreased in HPD. The imbalance potentially contributes to the occurrence of HPD and poor clinical prognosis. In addition, we analyzed ligand-receptor interactions between subsets. The ligand-receptor interaction "CD74-MIF" was absent in HPD. However, in vitro experiment, we found that CD74 regulated effector function of effector CD8+ T cells. Overall, the article provides a primary study of immune profile in HPD.

Hypoxia-Inducible Factor-1α Protects Against Intervertebral Disc Degeneration Through Antagonizing Mitochondrial Oxidative Stress.

Intervertebral disc degeneration (IVDD) demonstrates a gradually increased incidence and has developed into a major health problem worldwide. The nucleus pulposus is characterized by the hypoxic and avascular environment, in which hypoxia-inducible factor-1α (HIF-1α) has an important role through its participation in extracellular matrix synthesis, energy metabolism, cellular adaptation to stresses and genesis. In this study, the effects of HIF-1α on mouse primary nucleus pulposus cells (MNPCs) exposed to TNF-α were observed, the potential mechanism was explored and a rabbit IVDD model was established to verify the protective role of HIF-1α on IVDD. In vitro results demonstrated that HIF-1α could attenuate the inflammation, apoptosis and mitochondrial dysfunction induced by TNF-α in MNPCs; promote cellular anabolism; and inhibit cellular catabolism. In vivo results demonstrated that after establishment of IVDD model in rabbit, disc height and IVD extracellular matrix were decreased in a time-dependent manner, MRI analysis showed a tendency for decreased T2 values in a time-dependent manner and supplementation of HIF-1α improved histological and imaginative IVDD while downregulation of HIF-1α exacerbated this degeneration. In summary, HIF-1α protected against IVDD, possibly through reducing ROS production in the mitochondria and consequent inhibition of inflammation, metabolism disorders and apoptosis of MNPCs, which provided a potential therapeutic instrument for the treatment of IVDD diseases.

Overexpressed PKM2 promotes macrophage phagocytosis and atherosclerosis.

BACKGROUND: The expression of pyruvate kinase muscle 2 (PKM2) is augmented in macrophages of patients with atherosclerotic coronary artery disease. The role of PKM2 in atherosclerosis is to be determined. METHODS: Global and myeloid cell-specific PKM2 knock-in mice with ApoE-/- background (ApoE-/- , PKM2KI/KI and Lyz2-cre, ApoE-/- , and PKM2flox/flox ) were produced to evaluate the clinical significance of PKM2 in atherosclerosis development. Wild-type and PKM2 knock-in macrophages were isolated to assess the function of PKM2 in macrophage phagocytosis. Atherosclerotic mice were treated with PKM2 inhibitor shikonin (SKN) to evaluate the therapeutic potential of PKM2 suppression in atherosclerosis. RESULTS: Oxidized low-density lipoprotein (oxLDL) upregulated PKM2 in macrophages. PKM2 in return promoted the uptake of oxLDL by macrophages. Overexpressed PKM2 accelerated atherosclerosis in mice. SKN blocked the progress of mouse atherosclerosis. CONCLUSIONS: PKM2 accelerates macrophage phagocytosis and atherosclerosis. Targeting PKM2 is a potential therapy for atherosclerosis.

Oncogenic ß-catenin stimulation of AKT2-CAD-mediated pyrimidine synthesis is targetable vulnerability in liver cancer.

CTNNB1, encoding ß-catenin protein, is the most frequently altered proto-oncogene in hepatic neoplasms. In this study, we studied the significance and pathological mechanism of CTNNB1 gain-of-function mutations in hepatocarcinogenesis. Activated ß-catenin not only triggered hepatic tumorigenesis but also exacerbated Tp53 deletion or hepatitis B virus infection-mediated liver cancer development in mouse models. Using untargeted metabolomic profiling, we identified boosted de novo pyrimidine synthesis as the major metabolic aberration in ß-catenin mutant cell lines and livers. Oncogenic ß-catenin transcriptionally stimulated AKT2, which then phosphorylated the rate-limiting de novo pyrimidine synthesis enzyme CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, dihydroorotase) on S1406 and S1859 to potentiate nucleotide synthesis. Moreover, inhibition of ß-catenin/AKT2-stimulated pyrimidine synthesis axis preferentially repressed ß-catenin mutant cell proliferation and tumor formation. Therefore, ß-catenin active mutations are oncogenic in various preclinical liver cancer models. Stimulation of ß-catenin/AKT2/CAD signaling cascade on pyrimidine synthesis is an essential and druggable vulnerability for ß-catenin mutant liver cancer.

eIF4A1 Inhibitor Suppresses Hyperactive mTOR-Associated Tumors by Inducing Necroptosis and G2/M Arrest.

Aberrantly activated mechanistic target of rapamycin (mTOR) signaling pathway stimulates translation initiation/protein synthesis and eventually causes tumors. Targeting these processes thus holds potential for treating mTOR-associated diseases. We tested the potential of eFT226, a sequence-selective inhibitor of eIF4A-mediated translation, in the treatment of mTOR hyperactive cells caused by the deletion of tuberous sclerosis complex 1/2 (TSC1/2) or phosphatase and TENsin homology (PTEN). eFT226 preferentially inhibited the proliferation of Tsc2- and Pten-deficient cells by inducing necroptosis and G2/M phase arrest. In addition, eFT226 blocked the development of TSC2-deficient tumors. The translation initiation inhibitor is thus a promising regimen for the treatment of hyperactive mTOR-mediated tumors.

xCT contributes to colorectal cancer tumorigenesis through upregulation of the MELK oncogene and activation of the AKT/mTOR cascade.

Colorectal cancer (CRC) is one of the most commonly diagnosed and deadly malignant tumors globally, and its occurrence and progression are closely related to the poor histological features and complex molecular characteristics among patients. It is urgent to identify specific biomarkers for effective treatment of CRC. In this study, we performed comprehensive experiments to validate the role of xCT expression in CRC tumorigenesis and stemness and confirmed xCT knockdown significantly suppressed the proliferation, migration, and stemness of CRC cells in vitro and effectively inhibited CRC tumorigenesis and metastasis in vivo. In addition, bioinformatic analysis and luciferase assays were used to identify E2F1 as a critical upstream transcription factor of SLC7A11 (the gene encoding for xCT) that facilitated CRC progression and cell stemness. Subsequent RNA sequencing, western blotting, rescue assay, and immunofluorescence assays revealed MELK directly co-expressed with xCT in CRC cells, and its upregulation significantly attenuated E2F1/xCT-mediated tumorigenesis and stemness in CRC. Further molecular mechanism exploration confirmed that xCT knockdown may exert an antitumor effect by controlling the activation of MELK-mediated Akt/mTOR signaling. Erastin, a specific inhibitor of xCT, was also proven to effectively inhibit CRC tumorigenesis and cell stemness. Altogether, our study showed that E2F1/xCT is a promising therapeutic target of CRC that promotes tumorigenesis and cell stemness. Erastin is also an effective antitumoral agent for CRC.

A Potential Diagnostic and Prognostic Biomarker TMEM176B and Its Relationship With Immune Infiltration in Skin Cutaneous Melanoma.

Background: Melanoma is a highly malignant and aggressive tumor. The search for new and effective biomarkers facilitates early diagnosis and treatment, ultimately improving the prognosis of melanoma patients. Although the transmembrane protein TMEM176B has been linked to a number of cancers, its role in cancer immunity remains unknown. Methods: Expression levels of TMEM176B in normal tissues and several cancers, including Skin Cutaneous Melanoma (SKCM), were collected from TCGA and GTEx. We used Receiver operating characteristic and Kaplan-Meier survival curves and performed regression analysis to elucidate the link between TMEM176B and clinicopathological features of SKCM in order to determine the prognostic significance of TMEM176B in SKCM. We then used the GEPIA and STRING websites to search for proteins and associated top genes that may interact with TMEM176B and enriched them for analysis. The link between TMEM176B and immune cells infiltration was then investigated using TIMER, CIBERSORT algorithm and GSVA package of R (v3.6.3). Finally, animal tests were conducted to confirm the expression of Tmem176b and its influence on T-cell immune infiltration. Results: TMEM176B expression was considerably elevated in SKCM compared to normal tissues. Particularly, TMEM176B expression was also linked to pathological stage, tumor ulceration and radiation therapy. Patients with elevated TMEM176B expression had a better prognosis, according to the survival analysis. The majority of tumor infiltrating lymphocytes (TILs) especially T cells in SKCM was positively linked with TMEM176B expression. Our animal experiments also verified that the T-cell infiltration was significantly inhibited in local melanoma tissue of Tmem176b knockout mice. At the same time deleting Tmem176b accelerated tumor progress and impaired T cells effector function. Conclusion: Upregulated expression of TMEM176B in SKCM is associated with a better prognosis and it has the potential to serve as a diagnostic and prognostic marker for the disease. It may serve as a target for SKCM immunotherapy by regulating CD8+ T cells although it requires more evidence.