CircUBA2 promotes the cancer stem cell-like properties of gastric cancer through upregulating STC1 via sponging miR-144-5p.

BACKGROUND: Cancer stem cells (CSCs) are critical factors that limit the effectiveness of gastric cancer (GC) therapy. Circular RNAs (circRNAs) are confirmed as important regulators of many cancers. However, their role in regulating CSC-like properties of GC remains largely unknown. Our study aimed to investigate the role of circUBA2 in CSC maintenance and the underlying mechanisms. METHODS: We identified circUBA2 as an upregulated gene using circRNA microarray analysis. qRT-PCR was used to examine the circUBA2 levels in normal and GC tissues. In vitro and in vivo functional assays were performed to validate the role of circUBA2 in proliferation, migration, metastasis and CSC-like properties of GC cell. The relationship between circUBA2, miR-144-5p and STC1 was characterised using bioinformatics analysis, a dual fluorescence reporter system, FISH, and RIP assays. RESULTS: CircUBA2 expression was significantly increased in GC tissues, and patients with GC with high circUBA2 expression had a poor prognosis. CircUBA2 enhances CSC-like properties of GC, thereby promoting cell proliferation, migration, and metastasis. Mechanistically, circUBA2 promoted GC malignancy and CSC-like properties by acting as a sponge for miR-144-5p to upregulate STC1 expression and further activate the IL-6/JAK2/STAT3 signaling pathway. More importantly, the ability of circUBA2 to enhance CSC-like properties was inhibited by tocilizumab, a humanised Interleukin-6 receptor (IL-6R) antibody. Thus, circUBA2 knockdown and tocilizumab synergistically inhibited CSC-like properties. CONCLUSIONS: Our study demonstrated the critical role of circUBA2 in regulating CSC-like properties in GC. CircUBA2 may be a promising prognostic biomarker for GC.

Cystathionine γ-lyase inhibits mitochondrial oxidative stress by releasing H2S nearby through the AKT/NRF2 signaling pathway.

Cystathionine γ-lyase (CSE) is a major enzyme that produces hydrogen sulfide (H2S). Herein, we report how CSE plays a previously unknown role in regulating the antioxidant effects of the mitochondria in human umbilical vein endothelial cells by releasing H2S nearby under stress conditions. We found that H2S partially promoted angiogenesis in the endothelial cells through the AKT/nuclear factor erythroid 2-related factor 2 (AKT/NRF2) signaling pathway. H2S improved mitochondrial function by altering the expressions of the mitofusin2 and dynamin-1-like mitochondrial fission proteins to inhibit oxidative stress and enhance NRF2 nuclear translocation. CSE is located only in the cytoplasm and not in the mitochondria, but it is transported to the vicinity of the mitochondria to produce H2S, which plays an antioxidant role in human umbilical vein endothelial cells under stress. The CSE mutant (with mutated CSE activity center: CSED187A) partially decreased the effects on promoting angiogenesis, resisting oxidative stress, and entering the mitochondria. These results show that CSE translocation is a unique mechanism that promotes H2S production inside the mitochondria under stress stimulation. Therefore, the CSE mutant site (CSED187A) may be a potential target for drug therapy.

Serum Metabolomic Profile in Hypoxia-Induced Pulmonary Hypertension Mice after C75 Treatment.

BACKGROUND: Inhibition of fatty acid synthase (FAS) plays a crucial protective role in pulmonary hypertension (PH). Our aim was to identify novel metabolites in mice with hypoxia-induced PH after treatment with C75 (FAS inhibitor) and to confirm the presence of these metabolites in paediatric patients with PH. METHODS: The PH mouse model was built by chronic hypoxia and ovalbumin (OVA) assistance. Untargeted metabolomics was used to analyse mouse serum. Six children with PH and six relative controls (patients without lung and heart disease) were selected in Shanghai Children's Hospital and they all performed blood tandem mass spectrometry during hospitalization. RESULTS: First, a total of 29 differential metabolites, including lipid metabolites, polyamine, and glutamine were identified as differential metabolites in the hypoxia group compared with the control group. After C75 treatment, symptoms were partially relieved in the PH mouse, and 15 differential metabolites, including lipid metabolites, polyamine, and glutamine were identified in the hypoxia + C75 group compared with the hypoxia group. These differential metabolites were enriched in arginine and glycerolipid metabolism through metabolite set enrichment analyses and were involved in excessive cell proliferation, which was a characteristic of PH. Second, glutamine and caproyl carnitine levels were increased in paediatric patients with PH. CONCLUSIONS: FAS may be a potential PH therapeutic target. Lipid metabolites, polyamine, and glutamine, are closely related to PH. Putrescine and glutamine might be biomarkers for PH.

Tumor Immunophenotyping-Derived Signature Identifies Prognosis and Neoadjuvant Immunotherapeutic Responsiveness in Gastric Cancer.

The effectiveness of neoadjuvant immune checkpoint inhibitor (ICI) therapy is confirmed in clinical trials; however, the patients suitable for receiving this therapy remain unspecified. Previous studies have demonstrated that the tumor microenvironment (TME) dominates immunotherapy; therefore, an effective TME classification strategy is required. In this study, five crucial immunophenotype-related molecules (WARS, UBE2L6, GZMB, BATF2, and LAG-3) in the TME are determined in five public gastric cancer (GC) datasets (n = 1426) and an in-house sequencing dataset (n = 79). Based on this, a GC immunophenotypic score (IPS) is constructed using the least absolute shrinkage and selection operator (LASSO) Cox, and randomSurvivalForest. IPSLow is characterized as immune-activated, and IPSHigh is immune-silenced. Data from seven centers (n = 1144) indicate that the IPS is a robust and independent biomarker for GC and superior to the AJCC stage. Furthermore, patients with an IPSLow and a combined positive score of ≥5 are likely to benefit from neoadjuvant anti-PD-1 therapy. In summary, the IPS can be a useful quantitative tool for immunophenotyping to improve clinical outcomes and provide a practical reference for implementing neoadjuvant ICI therapy for patients with GC.

Comparative transcription profiling of mRNA and lncRNA in pulmonary arterial hypertension after C75 treatment.

OBJECTIVES: To investigate mRNA and long non-coding RNA (lncRNA) expression profiles in monocrotaline (MCT)- mice. MATERIALS AND METHODS: Lung tissues (Control-Vehicle, MCT-Vehicle, and MCT-C75) were examined by high-throughput sequencing (HTS). Aberrantly expressed mRNAs and lncRNAs were analyzed by bioinformatics. Cell proliferation and cell cycle analysis were performed to detect the potential protective effects of C75, an inhibitor of fatty acid synthase. The signaling pathways associated with inflammatory responses were verified by real time-PCR. RESULTS: RNA sequencing data reveals 285 differentially expressed genes (DEGs) and 147 lncRNAs in the MCT-Vehicle group compared to the control. After five-week of C75 treatment, 514 DEGs and 84 lncRNAs are aberrant compared to the MCT-Vehicle group. Analysis of DEGs and lncRNA target genes reveals that they were enriched in pathways related to cell cycle, cell division, and vascular smooth muscle contraction that contributes to the PAH pathological process. Subsequently, the expression of eight DEGs and three lncRNAs is verified using RT-PCR. Differentially expressed lncRNAs (ENSMUSG00000110393.2, Gm38850, ENSMUSG00000100465.1, ENSMUSG00000110399.1) may associate in PAH pathogenesis as suggested by co-expression network analysis. C75 can protect against MCT-induced PAH through its anti-inflammatory and anti-proliferation. CONCLUSIONS: These DEGs and lncRNAs can be considered as novel candidate regulators of PAH pathogenesis. We propose that C75 treatment can partially reverse PAH pathogenesis through modulating cell cycle, cell proliferation, and anti-inflammatory.

An immunosuppressive scoring system to predict recurrence and assist in decision regarding postoperative adjuvant treatment in gastric cancer.

Inhibition of the immune microenvironment is the main cause of tumor recurrence after surgery in patients with gastric cancer (GC). In this study, immunohistochemistry and multiple immunofluorescence staining were used to evaluate immunosuppressive indicators and immune biomarkers in 825 patients with gastric cancer from three centers. We constructed an immunosuppressive recurrence score (IRS) using LASSO Cox regression based on the expression of six immunosuppressive indicators and found that the IRS and IRS-based nomogram were significantly accurate and reliable in predicting recurrence. Moreover, an elevated IRS was associated with locoregional recurrence and postoperative adjuvant chemotherapy failure. Furthermore, an increase in IRS indicated inhibition of the antitumor effect of CD8+ tumor-infiltrating lymphocytes in the invasive margin. Thus, we propose that the IRS can predict the recurrence outcome of patients with GC by distinguishing the immunosuppressive status, which is helpful in the selection of individualized adjuvant treatment plans.

m6A methylation mediates LHPP acetylation as a tumour aerobic glycolysis suppressor to improve the prognosis of gastric cancer.

LHPP, a histidine phosphatase, has been implicated in tumour progression. However, its role, underlying mechanisms, and prognostic significance in human gastric cancer (GC) are elusive. Here, we obtained GC tissues and corresponding normal tissues from 48 patients and identified LHPP as a downregulated gene via RNA-seq. qRT-PCR and western blotting were applied to examine LHPP levels in normal and GC tissues. The prognostic value of LHPP was elucidated using tissue microarray and IHC analyses in two independent GC cohorts. The functional roles and mechanistic insights of LHPP in GC growth and metastasis were evaluated in vitro and in vivo. The results showed that LHPP expression was significantly decreased in GC tissues at both the mRNA and protein levels. Multivariate Cox regression analysis revealed that LHPP was an independent prognostic factor and effective predictor in patients with GC. The low expression of LHPP was significantly related to the poor prognosis and chemotherapy sensitivity of gastric cancer patients. Moreover, elevated LHPP expression effectively suppressed GC growth and metastasis in vitro and in vivo. Mechanistically, the m6A modification of LHPP mRNA by METTL14 represses its expression; LHPP inhibits the phosphorylation of GSK3b through acetylation and mediates HIF1A to inhibit glycolysis, proliferation, invasion and metastasis of gastric cancer cells. Together, our findings suggest that LHPP is regulated by m6A methylation and regulates the metabolism of GC by changing the acetylation level. Thus, LHPP is a potential predictive biomarker and therapeutic target for GC.

TECRL deficiency results in aberrant mitochondrial function in cardiomyocytes.

Sudden cardiac death (SCD) caused by ventricular arrhythmias is the leading cause of mortality of cardiovascular disease. Mutation in TECRL, an endoplasmic reticulum protein, was first reported in catecholaminergic polymorphic ventricular tachycardia during which a patient succumbed to SCD. Using loss- and gain-of-function approaches, we investigated the role of TECRL in murine and human cardiomyocytes. Tecrl (knockout, KO) mouse shows significantly aggravated cardiac dysfunction, evidenced by the decrease of ejection fraction and fractional shortening. Mechanistically, TECRL deficiency impairs mitochondrial respiration, which is characterized by reduced adenosine triphosphate production, increased fatty acid synthase (FAS) and reactive oxygen species production, along with decreased MFN2, p-AKT (Ser473), and NRF2 expressions. Overexpression of TECRL induces mitochondrial respiration, in PI3K/AKT dependent manner. TECRL regulates mitochondrial function mainly through PI3K/AKT signaling and the mitochondrial fusion protein MFN2. Apoptosis inducing factor (AIF) and cytochrome C (Cyc) is released from the mitochondria into the cytoplasm after siTECRL infection, as demonstrated by immunofluorescent staining and western blotting. Herein, we propose a previously unrecognized TECRL mechanism in regulating CPVT and may provide possible support for therapeutic target in CPVT.

Generation of an induced pluripotent stem cell line from a Chinese Han infant with floating-harbor syndrome accompanied with dilated cardiomyopathy.

Floating-harbor syndrome, are mainly caused by heterozygous truncating mutations in SRCAP. To our best knowledge, the mutation (c.452_453del) located in the fifth exon of SRCAP, has not been reported yet. Herein, an induced pluripotent stem cell (iPSC) line was generated from the peripheral blood mononuclear cells of an infant with floating-harbor syndrome accompanied with dilated cardiomyopathy through Sendaivirus-mediated reprogramming. These iPSCs have excellent cellular features, including stable amplification, pluripotent markers expression, and spontaneous differentiation into three germ layers, and a normal karyotype. These iPSCs provide a suitable cell model to study the mechanism of Floating-harbor syndrome.