Cystathionine β-Synthase in Physiology and Cancer

Association between CBS gene T833C, G919A and 844ins68 polymorphisms in the 8th exon region and coronary artery disease: a meta-analysis

BACKGROUND

Several studies indicate that the cystathionine β-synthase (CBS) gene T833C, G919A and 844ins68 polymorphisms in the 8th exon region may be correlated with coronary artery disease (CAD) susceptibility, but the results have been inconsistent and inconclusive. Thus, a meta-analysis was conducted to provide a comprehensive estimate of these associations.

METHODS

On the basis of searches in the PubMed, EMBASE, Cochrane Library, Wanfang, VIP, and CNKI databases, we selected 14 case - control studies including 2123 cases and 2368 controls for this meta-analysis. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated accordingly using a fixed-effect or random-effect model.

RESULTS

The results indicated an increased risk between the CBS T833C gene polymorphisms and susceptibility to CAD under the dominant model (CC+CT vs. TT: OR = 1.92, 95% CI: 1.11 ~ 3.32), recessive model (CC vs. CT+TT: OR = 1.88, 95% CI: 1.17 ~ 3.03), and homozygous model (CC vs. TT: OR = 2.46, 95% CI: 1.04 ~ 5.83). In these three genetic models, no significant association was identified for CBS G919A (AA+AG vs. GG: OR = 1.48, 95% CI: 0.45 ~ 4.82),(AA vs. AG+GG: OR = 1.58, 95% CI: 0.93 ~ 2.70),(AA vs. GG: OR = 1.66, 95% CI: 0.40 ~ 6.92) or CBS 844ins68 (II+ID vs. DD: OR = 1.04, 95% CI: 0.80 ~ 1.35),(II vs. ID+DD: OR = 1.09, 95% CI: 0.51 ~ 2.36),(II vs. DD: OR = 1.10, 95% CI: 0.51 ~ 2.39).

CONCLUSIONS

This meta-analysis suggests that the CBS T833C gene polymorphism is significantly associated with the risk of CAD and it shows a stronger association in Asian populations. Individuals with the C allele of the CBS gene T833C polymorphism might be particularly susceptible to CAD.

The role of nonesterified fatty acids in cancer biology: Focus on tryptophan and related metabolism

Plasma nonesterified fatty acids (NEFA) are elevated in cancer, because of decreased albumin levels and of fatty acid oxidation, and increased fatty acid synthesis and lipolysis. Albumin depletion and NEFA elevation maximally release albumin-bound tryptophan (Trp) and increase its flux down the kynurenine pathway, leading to increased production of proinflammatory kynurenine metabolites, which tumors use to undermine T-cell function and achieve immune escape. Activation of the aryl hydrocarbon receptor by kynurenic acid promotes extrahepatic Trp degradation by indoleamine 2,3-dioxygenase and leads to upregulation of poly (ADP-ribose) polymerase, activation of which and also of SIRT1 (silent mating type information regulation 2 homolog 1) could lead to depletion of NAD+ and ATP, resulting in cell death. NEFA also modulate heme synthesis and degradation, changes in which impact homocysteine metabolism and production of reduced glutathione and hydrogen sulphide. The significance of the interactions between heme and homocysteine metabolism in cancer biology has received little attention. Targeting Trp disposition in cancer to prevent the NEFA effects is suggested.

Emerging roles of hydrogen sulfide in colorectal cancer

Hydrogen sulfide (H2S), an endogenous gasotransmitter, plays a key role in several critical physiological and pathological processes in vivo, including vasodilation, anti-infection, anti-tumor, anti-inflammation, and angiogenesis. In colorectal cancer (CRC), aberrant overexpression of H2S-producing enzymes has been observed. Due to the important role of H2S in the proliferation, growth, and death of cancer cells, H2S can serve as a potential target for cancer therapy. In this review, we thoroughly analyzed the underlying mechanism of action of H2S in CRC from the following aspects: the synthesis and catabolism of H2S in CRC cells and its effect on cell signal transduction pathways; the inhibition effects of exogenous H2S donors with different concentrations on the growth of CRC cells and the underlying mechanism of H2S in garlic and other natural products. Furthermore, we elucidate the expression characteristics of H2S in CRC and construct a comprehensive H2S-related signaling pathway network, which has important basic and practical significance for promoting the clinical research of H2S-related drugs.

Cystathionine--synthase expression correlates with tumour progression and adverse prognosis in patients with colon cancer

OBJECTIVE

To investigate the levels of cystathionine-β-synthase (CBS) in colon cancer tissues compared with adjacent control tissues; and to examine the relationship between CBS level and clinical characteristics and prognosis.

METHODS

This retrospective study enrolled patients with primary colon cancer. Paraffin-embedded specimens were used to create pathological tissue microarrays. Immunohistochemistry was performed on the microarray to detect the levels of CBS in colon cancer tissues and normal adjacent tissues. Analyses were undertaken to examine the relationship between the level of CBS and clinical characteristics and prognosis.

RESULTS

A total of 216 patients (107 males and 109 females) were included in the study. The level of CBS in cancer tissues was found to be significantly increased compared with normal adjacent control tissues. There were significant differences in tumour location, tumour-node-metastasis stage and survival rate between the CBS-negative and CBS-positive groups. Positive CBS immunostaining was associated with decreased survival in colon cancer patients. The results of multivariate Cox regression analysis revealed that tumour location and positive CBS immunostaining were independent prognostic factors for survival.

CONCLUSION

Positive CBS immunostaining was closely associated with colon cancer and high levels of CBS might accelerate tumour development and affect patient prognosis in colon cancer.

Recent advances in the role of hydrogen sulfide in age-related diseases

In recent years, the impact of age-related diseases on human health has become increasingly severe, and developing effective drugs to deal with these diseases has become an urgent task. Considering the essential regulatory role of hydrogen sulfide (H2S) in these diseases, it is regarded as a promising target for treatment. H2S is a novel gaseous transmitter involved in many critical physiological activities, including anti-oxidation, anti-inflammation, and angiogenesis. H2S also regulates cell activities such as cell proliferation, migration, invasion, apoptosis, and autophagy. These regulatory effects of H2S contribute to relieving and treating age-related diseases. In this review, we mainly focus on the pathogenesis and treatment prospects of H2S in regulating age-related diseases.

Epigenetic repression of de novo cysteine synthetases induces intra-cellular accumulation of cysteine in hepatocarcinoma by up-regulating the cystine uptake transporter xCT

BACKGROUND

The metabolic reprogramming of amino acids is critical for cancer cell growth and survival. Notably, intracellular accumulation of cysteine is often observed in various cancers, suggesting its potential role in alleviating the oxidative stress associated with rapid proliferation. The liver is the primary organ for cysteine biosynthesis, but much remains unknown about the metabolic alterations of cysteine and their mechanisms in hepatocellular carcinoma cells.

METHODS

RNA-seq data from patients with hepatocarcinoma were analyzed using the TNMplot database. The underlying mechanism of the oncogenic alteration of cysteine metabolism was studied in mice implanted with BNL 1ME A.7 R.1 hepatocarcinoma.

RESULTS

Database analysis of patients with hepatocellular carcinoma revealed that the expression of enzymes involved in de novo cysteine synthesis was down-regulated accompanying with increased expression of the cystine uptake transporter xCT. Similar alterations in gene expression have also been observed in a syngeneic mouse model of hepatocarcinoma. The enhanced expression of DNA methyltransferase in murine hepatocarcinoma cells caused methylation of the upstream regions of cysteine synthesis genes, thereby repressing their expression. Conversely, suppression of de novo cysteine synthesis in healthy liver cells induced xCT expression by up-regulating the oxidative-stress response factor NRF2, indicating that reduced de novo cysteine synthesis repulsively increases cystine uptake via enhanced xCT expression, leading to intracellular cysteine accumulation. Furthermore, the pharmacological inhibition of xCT activity decreased intracellular cysteine levels and suppressed hepatocarcinoma tumor growth in mice.

CONCLUSIONS

Our findings indicate an underlying mechanism of the oncogenic alteration of cysteine metabolism in hepatocarcinoma and highlight the efficacy of alteration of cysteine metabolism as a viable therapeutic target in cancer.

Bridging the Gap in Cancer Research: Sulfur Metabolism of Leukemic Cells with a Focus on L-Cysteine Metabolism and Hydrogen Sulfide-Producing Enzymes

Leukemias are cancers of the blood-forming system, representing a significant challenge in medical science. The development of leukemia cells involves substantial disturbances within the cellular machinery, offering hope in the search for effective selective treatments that could improve the 5-year survival rate. Consequently, the pathophysiological processes within leukemia cells are the focus of critical research. Enzymes such as cystathionine beta-synthase and sulfurtransferases like thiosulfate sulfurtransferase, 3-mercaptopyruvate sulfurtransferase, and cystathionine gamma-lyase play a vital role in cellular sulfur metabolism. These enzymes are essential to maintaining cellular homeostasis, providing robust antioxidant defenses, and supporting cell division. Numerous studies have demonstrated that cancerous processes can alter the expression and activity of these enzymes, uncovering potential vulnerabilities or molecular targets for cancer therapy. Recent laboratory research has indicated that certain leukemia cell lines may exhibit significant changes in the expression patterns of these enzymes. Analysis of the scientific literature and online datasets has confirmed variations in sulfur enzyme function in specific leukemic cell lines compared to normal leukocytes. This comprehensive review collects and analyzes available information on sulfur enzymes in normal and leukemic cell lines, providing valuable insights and identifying new research pathways in this field.

Mutations in Genes Producing Nitric Oxide and Hydrogen Sulfide and Their Connection With Apoptotic Genes in Chronic Myeloid Leukemia

Background Despite advances in chronic myeloid leukemia (CML) genetics, the role of nitric oxide (NO) and hydrogen sulfide (H2S) gene mutations and their relationship to apoptotic genes is unclear. Therefore, this study investigated NO- and H2S-producing genes' mutations and their interactions with apoptotic genes using Sanger sequencing and next-generation sequencing (NGS). Methodology A complete blood count (CBC) was carried out to measure the total number of white blood cells, while IL-6 levels were assessed in both control and CML patients using an ELISA technique. Sanger sequencing was used to analyze mutations in the CTH and NOS3 genes, whereas NGS was applied to examine mutations on all chromosomes. Results White blood cell (WBC) and granulocyte counts were significantly higher in CML patients compared to controls (p<0.0001), and monocyte counts were similarly higher (p<0.05). Interleukin-6 (IL-6) levels were significantly elevated in CML patients than controls (p<0.0001), indicating a possible link to CML etiology or progression. Multiple mutations have been identified in both genes, notably in CTH exon 12 and the NOS3 genes VNTR, T786C, and G894T. This study also measured IL-6 concentrations using IL-6 assays, identifying its potential as a CML prognostic diagnostic. WBC counts, granulocyte counts, and mid-range absolute counts, or MID counts, were significantly higher in CML patients than in normal control individuals. NGS identified 1643 somatic and sex chromosomal abnormalities and 439 actively expressed genes in CML patients. The findings imply a genomic landscape beyond the BCR-ABL1 mutation in CML development compared to other databases. Conclusion In conclusion, this study advances the understanding of the genetic characteristics of CML by identifying mutations in the NO- and H2S-producing genes and their complex connections with genes involved in apoptosis. The comprehensive genetic profile obtained by Sanger sequencing and NGS provides possibilities for identifying novel targets for therapy and personalized treatments for CML, therefore contributing to developments in hematological diseases.

Architecture and regulation of filamentous human cystathionine beta-synthase

Cystathionine beta-synthase (CBS) is an essential metabolic enzyme across all domains of life for the production of glutathione, cysteine, and hydrogen sulfide. Appended to the conserved catalytic domain of human CBS is a regulatory domain that modulates activity by S-adenosyl-L-methionine (SAM) and promotes oligomerisation. Here we show using cryo-electron microscopy that full-length human CBS in the basal and SAM-bound activated states polymerises as filaments mediated by a conserved regulatory domain loop. In the basal state, CBS regulatory domains sterically block the catalytic domain active site, resulting in a low-activity filament with three CBS dimers per turn. This steric block is removed when in the activated state, one SAM molecule binds to the regulatory domain, forming a high-activity filament with two CBS dimers per turn. These large conformational changes result in a central filament of SAM-stabilised regulatory domains at the core, decorated with highly flexible catalytic domains. Polymerisation stabilises CBS and reduces thermal denaturation. In PC-3 cells, we observed nutrient-responsive CBS filamentation that disassembles when methionine is depleted and reversed in the presence of SAM. Together our findings extend our understanding of CBS enzyme regulation, and open new avenues for investigating the pathogenic mechanism and therapeutic opportunities for CBS-associated disorders.

The unfolded protein response-glutathione metabolism axis: A novel target of a cycloruthenated complexes bypassing tumor resistance mechanisms

Platinum-based drugs remain the reference treatment for gastric cancer (GC). However, the frequency of resistance, due to mutations in TP53 or alterations in the energy and redox metabolisms, impairs the efficacy of current treatments, highlighting the need for alternative therapeutic options. Here, we show that a cycloruthenated compound targeting the redox metabolism, RDC11, induces higher cytotoxicity than oxaliplatin in GC cells and is more potent in reducing tumor growth in vivo. Detailed investigations into the mode of action of RDC11 indicated that it targets the glutathione (GSH) metabolism, which is an important drug resistance mechanism. We demonstrate that cycloruthenated complexes regulate the expression of enzymes of the transsulfuration pathway via the Unfolded Protein Response (UPR) and its effector ATF4. Furthermore, RDC11 induces the expression of SLC7A11 encoding for the cystine/glutamate antiporter xCT. These effects lead to a lower cellular GSH content and elevated oxygen reactive species production, causing the activation of a caspase-independent apoptosis. Altogether, this study provides the first evidence that cycloruthenated complexes target the GSH metabolism, neutralizing thereby a major resistance mechanism towards platinum-based chemotherapies and anticancer immune response.

Activatable Probes for Ratiometric Imaging of Endogenous Biomarkers In Vivo

Dynamic variations in the concentration and abnormal distribution of endogenous biomarkers are strongly associated with multiple physiological and pathological states. Therefore, it is crucial to design imaging systems capable of real-time detection of dynamic changes in biomarkers for the accurate diagnosis and effective treatment of diseases. Recently, ratiometric imaging has emerged as a widely used technique for sensing and imaging of biomarkers due to its advantage of circumventing the limitations inherent to conventional intensity-dependent signal readout methods while also providing built-in self-calibration for signal correction. Here, the recent progress of ratiometric probes and their applications in sensing and imaging of biomarkers are outlined. Ratiometric probes are classified according to their imaging mechanisms, and ratiometric photoacoustic imaging, ratiometric optical imaging including photoluminescence imaging and self-luminescence imaging, ratiometric magnetic resonance imaging, and dual-modal ratiometric imaging are discussed. The applications of ratiometric probes in the sensing and imaging of biomarkers such as pH, reactive oxygen species (ROS), reactive nitrogen species (RNS), glutathione (GSH), gas molecules, enzymes, metal ions, and hypoxia are discussed in detail. Additionally, this Review presents an overview of challenges faced in this field along with future research directions.

Association of genes in hereditary metabolic diseases with diagnosis, prognosis, and treatment outcomes in gastric cancer

Background

Aberrant metabolism is a major hallmark of cancers and hereditary diseases. Genes associated with inborn metabolic errors may also play roles in cancer development. This study evaluated the overall impact of these genes on gastric cancer (GC).

Methods

In total, 162 genes involved in 203 hereditary metabolic diseases were identified in the Human Phenotype Ontology database. Clinical and multi-omic data were acquired from the GC cohort of the Affiliated Hospital of Jiangsu University and other published cohorts. A 4-gene and 32-gene signature was established for diagnosis and prognosis or therapeutic prediction, respectively, and corresponding abnormal metabolism scores (AMscores) were calculated.

Results

The diagnostic AMscore showed high sensitivity (0.88-1.00) and specificity (0.89-1.00) to distinguish between GC and paired normal tissues, with area under the receiver operating characteristic curve (AUC) ranging from 0.911 to 1.000 in four GC cohorts. The prognostic or predictive AMscore was an independent predictor of overall survival (OS) in five GC cohorts and a predictor of the OS and disease-free survival benefit of postoperative chemotherapy or chemoradiotherapy in one GC cohort with such data. The AMscore adversely impacts immune biomarkers, including tumor mutation burden, tumor neoantigen burden, microsatellite instability, programmed death-ligand 1 protein expression, tumor microenvironment score, T cell receptor clonality, and immune cell infiltration detected by multiplex immunofluorescence staining. The AUC of the AMscore for predicting immunotherapy response ranging from 0.780 to 0.964 in four cohorts involving GC, urothelial cancer, melanoma, and lung cancer. The objective response rates in the low and high AMscore subgroups were 78.6% and 3.2%, 40.4% and 7%, 52.6% and 0%, and 72.7% and 0%, respectively (all p<0.001). In cohorts with survival data, a high AMscore was hazardous for OS or progression-free survival, with hazard ratios ranged from 5.79 to 108.59 (all p<0.001). Importantly, the AMscore significantly improved the prediction of current immune biomarkers for both response and survival, thus redefining the advantaged and disadvantaged immunotherapy populations.

Conclusions

Signatures based on genes associated with hereditary metabolic diseases and their corresponding scores could be used to guide the diagnosis and treatment of GC. Therefore, further validation is required.

Protein-Protein Interfaces as Druggable Targets: A Common Motif of the Pyridoxal-5'-Phosphate-Dependent Enzymes to Receive the Coenzyme from Its Producers

Pyridoxal-5'-phosphate (PLP), a phosphorylated form of vitamin B6, acts as a coenzyme for numerous reactions, including those changed in cancer and/or associated with the disease prognosis. Since highly reactive PLP can modify cellular proteins, it is hypothesized to be directly transferred from its donors to acceptors. Our goal is to validate the hypothesis by finding common motif(s) in the multitude of PLP-dependent enzymes for binding the limited number of PLP donors, namely pyridoxal kinase (PdxK), pyridox(am)in-5'-phosphate oxidase (PNPO), and PLP-binding protein (PLPBP). Experimentally confirmed interactions between the PLP donors and acceptors reveal that PdxK and PNPO interact with the most abundant PLP acceptors belonging to structural folds I and II, while PLPBP - with those belonging to folds III and V. Aligning sequences and 3D structures of the identified interactors of PdxK and PNPO, we have identified a common motif in the PLP-dependent enzymes of folds I and II. The motif extends from the enzyme surface to the neighborhood of the PLP binding site, represented by an exposed alfa-helix, a partially buried beta-strand, and residual loops. Pathogenicity of mutations in the human PLP-dependent enzymes within or in the vicinity of the motif, but outside of the active sites, supports functional significance of the motif that may provide an interface for the direct transfer of PLP from the sites of its synthesis to those of coenzyme binding. The enzyme-specific amino acid residues of the common motif may be useful to develop selective inhibitors blocking PLP delivery to the PLP-dependent enzymes critical for proliferation of malignant cells.

The Role of Hydrogen Sulfide in Regulation of Cell Death following Neurotrauma and Related Neurodegenerative and Psychiatric Diseases

Injuries of the central (CNS) and peripheral nervous system (PNS) are a serious problem of the modern healthcare system. The situation is complicated by the lack of clinically effective neuroprotective drugs that can protect damaged neurons and glial cells from death. In addition, people who have undergone neurotrauma often develop mental disorders and neurodegenerative diseases that worsen the quality of life up to severe disability and death. Hydrogen sulfide (H₂S) is a gaseous signaling molecule that performs various cellular functions in normal and pathological conditions. However, the role of H₂S in neurotrauma and mental disorders remains unexplored and sometimes controversial. In this large-scale review study, we examined the various biological effects of H₂S associated with survival and cell death in trauma to the brain, spinal cord, and PNS, and the signaling mechanisms underlying the pathogenesis of mental illnesses, such as cognitive impairment, encephalopathy, depression and anxiety disorders, epilepsy and chronic pain. We also studied the role of H₂S in the pathogenesis of neurodegenerative diseases: Alzheimer's disease (AD) and Parkinson's disease (PD). In addition, we reviewed the current state of the art study of H₂S donors as neuroprotectors and the possibility of their therapeutic uses in medicine. Our study showed that H₂S has great neuroprotective potential. H₂S reduces oxidative stress, lipid peroxidation, and neuroinflammation; inhibits processes associated with apoptosis, autophagy, ferroptosis and pyroptosis; prevents the destruction of the blood-brain barrier; increases the expression of neurotrophic factors; and models the activity of Ca²⁺ channels in neurotrauma. In addition, H₂S activates neuroprotective signaling pathways in psychiatric and neurodegenerative diseases. However, high levels of H₂S can cause cytotoxic effects. Thus, the development of H₂S-associated neuroprotectors seems to be especially relevant. However, so far, all H₂S modulators are at the stage of preclinical trials. Nevertheless, many of them show a high neuroprotective effect in various animal models of neurotrauma and related disorders. Despite the fact that our review is very extensive and detailed, it is well structured right down to the conclusions, which will allow researchers to quickly find the proper information they are interested in.

Integrated transcriptomics and metabolomics analysis reveals the biomolecular mechanisms associated to the antitumoral potential of a novel silver-based core@shell nanosystem

A combination of omics techniques (transcriptomics and metabolomics) has been used to elucidate the mechanisms responsible for the antitumor action of a nanosystem based on a Ag core coated with mesoporous silica on which transferrin has been anchored as a targeting ligand against tumor cells (Ag@MSNs-Tf). Transcriptomics analysis has been carried out by gene microarrays and RT-qPCR, while high-resolution mass spectrometry has been used for metabolomics. This multi-omics strategy has enabled the discovery of the effect of this nanosystem on different key molecular pathways including the glycolysis, the pentose phosphate pathway, the oxidative phosphorylation and the synthesis of fatty acids, among others.

Identification and Characterization of Metabolic Subtypes of Endometrial Cancer Using a Systems-Level Approach

Endometrial cancer (EC) is the most common gynecological cancer worldwide. Understanding metabolic adaptation and its heterogeneity in tumor tissues may provide new insights and help in cancer diagnosis, prognosis, and treatment. In this study, we investigated metabolic alterations of EC to understand the variations in metabolism within tumor samples. Integration of transcriptomics data of EC (RNA-Seq) and the human genome-scale metabolic network was performed to identify the metabolic subtypes of EC and uncover the underlying dysregulated metabolic pathways and reporter metabolites in each subtype. The relationship between metabolic subtypes and clinical variables was explored. Further, we correlated the metabolic changes occurring at the transcriptome level with the genomic alterations. Based on metabolic profile, EC patients were stratified into two subtypes (metabolic subtype-1 and subtype-2) that significantly correlated to patient survival, tumor stages, mutation, and copy number variations. We observed the co-activation of the pentose phosphate pathway, one-carbon metabolism, and genes involved in controlling estrogen levels in metabolic subtype-2, which is linked to poor survival. PNMT and ERBB2 are also upregulated in metabolic subtype-2 samples and present on the same chromosome locus 17q12, which is amplified. PTEN and TP53 mutations show mutually exclusive behavior between subtypes and display a difference in survival. This work identifies metabolic subtypes with distinct characteristics at the transcriptome and genome levels, highlighting the metabolic heterogeneity within EC.

Reconstruction of reverse transsulfuration pathway enables cysteine biosynthesis and enhances resilience to oxidative stress in Chinese Hamster Ovary cells

Cysteine is a critically important amino acid necessary for mammalian cell culture, playing key roles in nutrient supply, disulfide bond formation, and as a precursor to antioxidant molecules controlling cellular redox. Unfortunately, its low stability and solubility in solution make it especially problematic as an essential medium component that must be added to Chinese hamster ovary and other mammalian cell cultures. Therefore, CHO cells have been engineered to include the capacity of endogenously synthesizing cysteine by overexpressing multiple enzymes, including cystathionine beta-synthase (CBS), cystathionine gamma-lyase (CTH) and glycine N-methyltransferase (GNMT) to reconstruct the reverse transsulfuration pathway and overcome a key metabolic bottleneck. Some limited cysteine biosynthesis was obtained by overexpressing CBS and CTH for converting homocysteine to cysteine but robust metabolic synthesis from methionine was only possibly after incorporating GNMT which likely represents a key bottleneck step in the cysteine biosynthesis pathway. CHO cells with the reconstructed pathway exhibit the strong capability to proliferate in cysteine-limited and cysteine-free batch and fed-batch cultures at levels comparable to wildtype cells with ample cysteine supplementation, providing a selectable marker for CHO cell engineering. GNMT overexpression led to the accumulation of sarcosine byproduct, but its accumulation did not affect cell growth. Furthermore, pathway reconstruction enhanced CHO cells' reduced and glutathione levels in cysteine-limited conditions compared to unmodified cells, and greatly enhanced survivability and maintenance of redox homeostasis under oxidative stress induced by addition of menadione in cysteine-deficient conditions. Such engineered CHO cell lines can potentially reduce or even eliminate the need to include cysteine in culture medium, which not only reduces the cost of mammalian media but also promises to transform media design by solving the challenges posed by low stability and solubility of cysteine and cystine in future mammalian biomanufacturing processes.

The Relationship between Elevated Homocysteine and Metabolic Syndrome in a Community-Dwelling Middle-Aged and Elderly Population in Taiwan

(1) Background: Metabolic syndrome has become a serious health problem in society. Homocysteine is a biomarker for cardiovascular disease. We investigated the relationship between homocysteine levels and metabolic syndrome. (2) Methods: A total of 398 middle-aged and elderly individuals were included in our study. First, we divided the participants into two groups: the metabolic syndrome group and the nonmetabolic syndrome group. Second, according to tertiles of homocysteine levels from low to high, the participants were divided into first, second, and third groups. Pearson's correlation was then calculated for homocysteine levels and metabolic factors. Scatterplots are presented. Finally, the risk of metabolic syndrome in the second and third groups compared with the first group was assessed by multivariate logistic regression. (3) Results: In our study, the metabolic syndrome group had higher homocysteine levels, and the participants in the third group were more likely to have metabolic syndrome. Multivariate logistic regression revealed that the third group, which had the highest homocysteine level, was associated with metabolic syndrome with an odds ratio of 2.32 compared with the first group after adjusting for risk factors. (4) Conclusions: We concluded that high plasma homocysteine levels were independently associated with MetS in our study population.

Dysregulated Polycomb Repressive Complex 2 contributes to chronic obstructive pulmonary disease by rewiring stem cell fate

Aberrant lung cell differentiation is a hallmark of many lung diseases including chronic obstructive pulmonary disease (COPD). The EZH2-containing Polycomb Repressive Complex 2 (PRC2) regulates embryonic lung stem cell fate, but its role in adult lung is obscure. Histological analysis of patient tissues revealed that loss of PRC2 activity was correlated with aberrant bronchiolar cell differentiation in COPD lung. Histological and single-cell RNA-sequencing analyses showed that loss of EZH2 in mouse lung organoids led to lowered self-renewal capability, increased squamous morphological development, and marked shifts in progenitor cell populations. Evaluation of in vivo models revealed that heterozygosity of Ezh2 in mice with ovalbumin-induced lung inflammation led to epithelial cell differentiation patterns similar to those in COPD lung. We also identified cystathionine-β-synthase as a possible upstream factor for PRC2 destabilization. Our findings suggest that PRC2 is integral to facilitating proper lung stem cell differentiation in humans and mice.

Methanolic Extract of Aerva javanica Leaves Prevents LPS-Induced Depressive Like Behavior in Experimental Mice

Aim

Depression is a chronic recurrent neuropsychiatric disorder associated with inflammation. This study explored the pharmacological activities of Aerva javanica leaves crude extract (Aj.Cr) on lipopolysaccharide (LPS)-induced depressive-like behavior in experimental mice.

Methods

Aj.Cr was evaluated for its phenolic and flavonoid contents, bioactive potential, amino acid profiling and enzyme inhibition assays using different analytical techniques followed by in-silico molecular docking was performed. In addition, three ligands identified in HPLC analysis and standard galantamine were docked to acetyl cholinesterase (AchE) enzyme to assess the ligand interaction along with their binding affinities. In in-vivo analysis, mice were given normal saline (10 mL/kg), imipramine (10 mg/kg) and Aj.Cr (100, 300, and 500 mg/kg) orally for 14-consecutive days. On the 14th day, respective treatment was given 30-minutes before intra-peritoneal administration of (0.83 mg/kg) LPS. Open field, forced swim and tail suspension tests were performed 24-hours after LPS injection, followed by a sucrose preference test 48-hours later. Serum corticosterone levels, as well as levels of nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), tumor necrosis factor-alpha (TNF-), interleukin-1β (IL-1β), interleukin-6 (IL-6), brain-derived neurotrophic factor (BDNF) and catecholamines were determined in brain tissues.

Results

In-vitro results revealed that crude extract of Aj.Cr possesses anti-depressant agents with solid antioxidant potential. In-vivo analysis showed that LPS significantly increased depressive-like behavior followed by alteration in serum and tissue biomarkers as compared to normal control (p < 0.001). While imipramine and Aj.Cr (100, 300, and 500 mg/kg) treated groups significantly (p<0.05) improved the depressive-like behavior and biomarkers when compared to the LPS group.

Conclusion

The mitigation of LPS-induced depressive-like behavior by Aj.Cr may be linked to the modulation of oxidative stress, neuro-inflammation and catecholamines due to the presence of potent bioactive compounds exerting anti-depressant effects.

Apolipoprotein C1 promotes glioblastoma tumorigenesis by reducing KEAP1/NRF2 and CBS-regulated ferroptosis

Glioblastoma (GBM), a malignant brain tumor, is a world-wide health problem because of its poor prognosis and high rates of recurrence and mortality. Apolipoprotein C1 (APOC1) is the smallest of apolipoproteins, implicated in many diseases. Recent studies have shown that APOC1 promotes tumorigenesis and development of several types of cancer. In this study we investigated the role of APOC1 in GBM tumorigenesis. Using in silico assays we showed that APOC1 was highly expressed in GBM tissues and its expression was closely related to GBM progression. We showed that APOC1 protein expression was markedly increased in four GBM cell lines (U251, U138, A172 and U87) compared to the normal brain glia cell lines (HEB, HA1800). In U251 cells, overexpression of APOC1 promoted cell proliferation, migration, invasion and colony information, which was reversed by APOC1 knockdown. APOC1 knockdown also markedly inhibited the growth of GBM xenografts in the ventricle of nude mice. We further demonstrated that APOC1 reduced ferroptosis by inhibiting KEAP1, promoting nuclear translocation of NRF2 and increasing expression of HO-1 and NQO1 in GBM cells. APOC1 also induced ferroptosis resistance by increasing cystathionine beta-synthase (CBS) expression, which promoted trans-sulfuration and increased GSH synthesis, ultimately leading to an increase in glutathione peroxidase-4 (GPX4). Thus, APOC1 plays a key role in GBM tumorigenesis, conferring resistance to ferroptosis, and may be a promising therapeutic target for GBM.

Metabolism of Selenium, Selenocysteine, and Selenoproteins in Ferroptosis in Solid Tumor Cancers

A potential target of precision nutrition in cancer therapeutics is the micronutrient selenium (Se). Se is metabolized and incorporated as the amino acid selenocysteine (Sec) into 25 human selenoproteins, including glutathione peroxidases (GPXs) and thioredoxin reductases (TXNRDs), among others. Both the processes of Se and Sec metabolism for the production of selenoproteins and the action of selenoproteins are utilized by cancer cells from solid tumors as a protective mechanism against oxidative damage and to resist ferroptosis, an iron-dependent cell death mechanism. Protection against ferroptosis in cancer cells requires sustained production of the selenoprotein GPX4, which involves increasing the uptake of Se, potentially activating Se metabolic pathways such as the trans-selenation pathway and the TXNRD1-dependent decomposition of inorganic selenocompounds to sustain GPX4 synthesis. Additionally, endoplasmic reticulum-resident selenoproteins also affect apoptotic responses in the presence of selenocompounds. Selenoproteins may also help cancer cells adapting against increased oxidative damage and the challenges of a modified nutrient metabolism that result from the Warburg switch. Finally, cancer cells may also rewire the selenoprotein hierarchy and use Se-related machinery to prioritize selenoproteins that are essential to the adaptations against ferroptosis and oxidative damage. In this review, we discuss both the evidence and the gaps in knowledge on how cancer cells from solid tumors use Se, Sec, selenoproteins, and the Se-related machinery to promote their survival particularly via resistance to ferroptosis.

Gasotransmitters in the tumor microenvironment: Impacts on cancer chemotherapy (Review)

Nitric oxide, carbon monoxide and hydrogen sulfide are three endogenous gasotransmitters that serve a role in regulating normal and pathological cellular activities. They can stimulate or inhibit cancer cell proliferation and invasion, as well as interfere with cancer cell responses to drug treatments. Understanding the molecular pathways governing the interactions between these gases and the tumor microenvironment can be utilized for the identification of a novel technique to disrupt cancer cell interactions and may contribute to the conception of effective and safe cancer therapy strategies. The present review discusses the effects of these gases in modulating the action of chemotherapies, as well as prospective pharmacological and therapeutic interfering approaches. A deeper knowledge of the mechanisms that underpin the cellular and pharmacological effects, as well as interactions, of each of the three gases could pave the way for therapeutic treatments and translational research.

Cystathionine-β-synthase is essential for AKT-induced senescence and suppresses the development of gastric cancers with PI3K/AKT activation

Hyperactivation of oncogenic pathways downstream of RAS and PI3K/AKT in normal cells induces a senescence-like phenotype that acts as a tumor-suppressive mechanism that must be overcome during transformation. We previously demonstrated that AKT-induced senescence (AIS) is associated with profound transcriptional and metabolic changes. Here, we demonstrate that human fibroblasts undergoing AIS display upregulated cystathionine-β-synthase (CBS) expression and enhanced uptake of exogenous cysteine, which lead to increased hydrogen sulfide (H2S) and glutathione (GSH) production, consequently protecting senescent cells from oxidative stress-induced cell death. CBS depletion allows AIS cells to escape senescence and re-enter the cell cycle, indicating the importance of CBS activity in maintaining AIS. Mechanistically, we show this restoration of proliferation is mediated through suppressing mitochondrial respiration and reactive oxygen species (ROS) production by reducing mitochondrial localized CBS while retaining antioxidant capacity of transsulfuration pathway. These findings implicate a potential tumor-suppressive role for CBS in cells with aberrant PI3K/AKT pathway activation. Consistent with this concept, in human gastric cancer cells with activated PI3K/AKT signaling, we demonstrate that CBS expression is suppressed due to promoter hypermethylation. CBS loss cooperates with activated PI3K/AKT signaling in promoting anchorage-independent growth of gastric epithelial cells, while CBS restoration suppresses the growth of gastric tumors in vivo. Taken together, we find that CBS is a novel regulator of AIS and a potential tumor suppressor in PI3K/AKT-driven gastric cancers, providing a new exploitable metabolic vulnerability in these cancers.

Hydrogen sulfide decreases photodynamic therapy outcome through the modulation of the cellular redox state

Photodynamic therapy (PDT) is a non-surgical treatment that has been approved for its human medical use in many cancers. PDT involves the interaction of a photosensitizer (PS) with light. The amino acid 5- aminolevulinic acid (ALA) can be used as a pro-PS, leading to the synthesis of Protoporphyrin IX. Hydrogen sulfide (H₂S) is an endogenously produced gas that belongs to the gasotransmitter family, which can diffuse through biological membranes and have relevant physiological effects such as cardiovascular functions, vasodilatation, inflammation, cell cycle and neuro-modulation. It was also proposed to have cytoprotective effects. We aimed to study the modulatory effects of H₂S on ALAPDT in the mammary adenocarcinoma cell line LM2. Exposure of the cells to NaHS (donor of H₂S) in concentrations up to 10 mM impaired the response to ALA-PDT in a dose-dependent manner. The addition of 3 doses of NaHS showed the highest effect. This decreased response to the photodynamic treatment was correlated to an increase in the GSH levels, catalase activity, a dose dependent reduction of PpIX and increased intracellular ALA, decreased levels of oxidized proteins and a decrease of PDT-induced ROS. NaHS also reduced the levels of singlet oxygen in an in vitro assay. H₂S also protected other cells of different origins against PDT mediated by ALA and other PSs. These results suggest that H₂S has a role in the modulation of the redox state of the cells, and thus impairs the response to ALA-PDT through multifactor pathways. These findings could contribute to developing new strategies to improve the effectiveness of PDT particularly mediated by ALA or other ROS-related treatments.

In silico functional and structural characterization revealed virulent proteins of Francisella tularensis strain SCHU4

Francisella tularensis is a pathogenic, aerobic gram-negative coccobacillus bacterium. It is the causative agent of tularemia, a rare infectious disease that can attack skin, lungs, eyes, and lymph nodes. The genome of F. tularensis has been sequenced, and ~16% of the proteome is still uncharacterized. Characterizations of these proteins are essential to find new drug targets for better therapeutics. In silico characterization of proteins has become an extremely important approach to determine the functionality of proteins as experimental functional elucidation is unable to keep pace with the current growth of the sequence database. Initially, we have annotated 577 Hypothetical Proteins (HPs) of F. tularensis strain SCHU4 with seven bioinformatics tools which characterized them based on the family, domain and motif. Out of 577 HPs, 119 HPs were annotated by five or more tools and are further screened to predict their virulence properties, subcellular localization, transmembrane helices as well as physicochemical parameters. VirulentPred predicted 66 HPs out of 119 as virulent. These virulent proteins were annotated to find the interacting partner using STRING, and proteins with high confidence interaction scores were used to predict their 3D structures using Phyre2. The three virulent proteins Q5NH99 (phosphoserine phosphatase), Q5NG42 (Cystathionine beta-synthase) and Q5NG83 (Rrf2-type helix turn helix domain) were predicted to involve in modulation of cytoskeletal and innate immunity of host, H2S (hydrogen sulfide) based antibiotic tolerance and nitrite and iron metabolism of bacteria. The above predicted virulent proteins can serve as novel drug targets in the era of antibiotic resistance.

Therapeutic implication of carbon monoxide in drug resistant cancers

Drug resistance is the major obstacle that undermines effective cancer treatment. Recently, the application of gas signaling molecules, e.g., carbon monoxide (CO), in overcoming drug resistance has gained significant attention. Growing evidence showed that CO could inhibit mitochondria respiratory effect and glycolysis, two major ATP production pathways in cancer cells, and suppress angiogenesis and inhibit the activity of cystathionine β-synthase that is important in regulating cancer cells homeostasis, leading to synergistic effects when combined with cisplatin, doxorubicin, or phototherapy, etc. in certain resistant cancer cells. In the current review, we attempted to have a summary of these research conducted in the past decade using CO in treating drug resistant cancers, and have a detailed interpretation of the underlying mechanisms. The critical challenges will be discussed and potential solutions will also be provided. The information collected in this work will hopefully evoke more effects in using CO for the treatment of drug resistant cancers.

Cystathionine β-synthase expression correlates with tumor development and poor prognosis in patients with adenocarcinoma of the gastroesophageal junction

OBJECTIVES

To reveal the expression level of cystathionine β-synthase (CBS) in adenocarcinoma of esophagogastric junction (AEG) and discuss the relationship between CBS expression level and tumor microvascular density (MVD), clinical features and prognosis.

METHODS

Paraffin samples from 214 patients with AEG were selected to make pathological microchips. Immunohistochemistry was performed based on the microchips to detect the expression level of CBS and microvascular density (MVD) in cancer tissues and adjacent control tissues. Relationships between expression level of CBS and MVD, clinical characteristics and prognosis were analyzed.

RESULTS

In total, 214 AEG cases were classified into three groups: CBS negative staining (n=26), low staining (n=44), and high staining (n=144). Quantitative alterations in CBS and CD31 expression were explored using immunohistochemistry. The 5-year recurrence rate of enrolled patients was followed up and found that CBS expression was significantly increased in tumor tissue compared with adjacent non-tumor tissue (P<0.0001). There were significant differences in microvascular density between the groups with negative and high CBS staining (P<0.0001), and between the groups with low and high CBS staining (P<0.0001). Univariate analysis revealed significant differences in tumor stage (P<0.0001), T stage (P=0.008), N stage (P=0.028), differentiation degree (P=0.037), and 5-year survival (P=0.0034) among the three groups. Multivariate logic regression analysis showed that increased CBS scores were associated with an increased probability of 5-year recurrence (P=0.018). Finally, different CBS expression levels were associated with disease-free survival in AEG patients.

CONCLUSIONS

CBS expression level is closely related to microvascular density and tumor stage in AEG. High level of CBS not only accelerates tumor angiogenesis but also affects patient's survival and prognosis.

CBS-H2S axis preserves the intestinal barrier function by inhibiting COX-2 through sulfhydrating human antigen R in colitis

INTRODUCTION

Lipopolysaccharide (LPS) causes lesions of the epithelial barrier, which allows translocation of pathogens from the intestinal lumen to the host's circulation. Hydrogen sulfide (H₂S) regulates multiple physiological and pathological processes in colonic epithelial tissue, and CBS-H₂S axis involved in multiple gastrointestinal disorder. However, the mechanism underlying the effect of the CBS-H₂S axis on the intestinal and systemic inflammation in colitis remains to be illustrated.

OBJECTIVES

To investigate the effect of CBS-H₂S axis on the intestinal and systematic inflammation related injuries in LPS induced colitis and the underlying mechanisms.

METHODS

Wild type and CBS^-/+ mice were used to evaluate the effect of endogenous and exogenous H₂S on LPS-induced colitis in vivo. Cytokine quantitative antibody array, western blot and real-time PCR were applied to detect the key cytokines in the mechanism of action. Biotin switch of S-sulfhydration, CRISPR/Cas9 mediated knockout, immunofluorescence and ActD chase assay were used in the in vitro experiment to further clarify the molecular mechanisms.

RESULTS

H₂S significantly alleviated the symptoms of LPS-induced colitis in vivo and attenuated the increase of COX-2 expression. The sulfhydrated HuR increased when CBS express normally or GYY4137 was administered. While after knocking kown CBS, the expression of COX-2 in mice colon increased significantly, and the sulfhydration level of HuR decreased. The results in vitro illustrated that HuR can increase the stability of COX-2 mRNA, and the decrease of COX-2 were due to increased sulfhydration of HuR rather than the reduction of total HuR levels.

CONCLUSION

These results indicated that CBS-H₂S axis played an important role in protecting intestinal barrier function in colitis. CBS-H₂S axis increases the sulfhydration level of HuR, by which reduces the binding of HuR with COX-2 mRNA and inhibited the expression of COX-2.

Overexpression of CBS/H2S inhibits proliferation and metastasis of colon cancer cells through downregulation of CD44

Background

The role of hydrogen sulfide (H₂S) in cancer biology is controversial, including colorectal cancer. The bell-shaped effect of H₂S refers to pro-cancer action at lower doses and anti-cancer effect at higher concentrations. We hypothesized that overexpression of cystathionine-beta-synthase (CBS)/H₂S exerts an inhibitory effect on colon cancer cell proliferation and metastasis.

Methods

Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8), clone-formation and sphere formation assay. Cell migration was evaluated by transwell migration assay. Intracellular H₂S was detected by H₂S probe. Chromatin immunoprecipitation (ChIP) analysis was carried out to examine DNA–protein interaction. Cell experiments also included western blotting, flow cytometry, immunohistochemistry (IHC) and immunofluorescence analysis. We further conducted in vivo experiments to confirm our conclusions.

Results

Overexpression of CBS and exogenous H₂S inhibited colon cancer cell proliferation and migration in vitro. In addition, overexpression of CBS attenuated tumor growth and liver metastasis in vivo. Furthermore, CD44 and the transcription factor SP-1 was probably involved in the inhibitory effect of CBS/H₂S axis on colon cancer cells.

Conclusions

Overexpression of CBS and exogenous provision of H₂S inhibited colon cancer cell proliferation and migration both in vivo and in vitro. Molecular mechanisms might involve the participation of CD44 and the transcription factor SP-1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02512-2.

Proteomic profiling of cisplatin-resistant and cisplatin-sensitive germ cell tumour cell lines using quantitative mass spectrometry

Purpose

Advanced testicular germ cell tumours (GCT) generally have a good prognosis owing to their unique sensitivity towards cisplatin-based chemotherapies. However, cisplatin-resistant GCT have a poor outcome. Further studies are mandatory to better understand resistance mechanisms and develop therapeutic strategies for refractory GCTs.

Methods

Protein levels in cisplatin-resistant GCT cell lines of NTERA-2, NCCIT and 2102EP were analyzed by quantitative proteomic mass spectrometry (MS) in combination with stable isotope labelling by amino acids in cell culture (SILAC). Differentially abundant protein markers of acquired cisplatin resistance were validated by Western blotting. Comprehensive bioinformatical annotation using gene set enrichment analyses (GSEA) and STRING interaction analysis were performed to identify commonly affected pathways in cisplatin resistance and the data were compared to the GCT cohort of the ‘The Cancer Genome Atlas’.

Results

A total of 4375 proteins were quantified by MS, 144 of which were found to be differentially abundant between isogenic resistant and sensitive cell line pairs (24 proteins for NTERA-2, 60 proteins for NCCIT, 75 proteins for 2102EP). Western blotting confirmed regulation of key resistance-associated proteins (CBS, ANXA1, LDHA, CTH, FDXR). GSEA revealed a statistically significant enrichment of DNA repair-associated proteins in all three resistant cell lines and specific additional processes for individual cell lines.

Conclusion

High resolution MS combined with SILAC is a powerful tool and 144 significantly deregulated proteins were found in cisplatin-resistant GCT cell lines. Our study provides the largest proteomic in vitro library for cisplatin resistance in GCT, yet, enabling further studies to develop new treatment options for patients with refractory GCT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-03936-1.

Central Taurine Attenuates Hyperthermia and Isolation Stress Behaviors Augmented by Corticotropin-Releasing Factor with Modifying Brain Amino Acid Metabolism in Neonatal Chicks

The objective of this study was to determine the effects of centrally administered taurine on rectal temperature, behavioral responses and brain amino acid metabolism under isolation stress and the presence of co-injected corticotropin-releasing factor (CRF). Neonatal chicks were centrally injected with saline, 2.1 pmol of CRF, 2.5 μmol of taurine or both taurine and CRF. The results showed that CRF-induced hyperthermia was attenuated by co-injection with taurine. Taurine, alone or with CRF, significantly decreased the number of distress vocalizations and the time spent in active wakefulness, as well as increased the time spent in the sleeping posture, compared with the saline- and CRF-injected chicks. An amino acid chromatographic analysis revealed that diencephalic leucine, isoleucine, tyrosine, glutamate, asparagine, alanine, β-alanine, cystathionine and 3-methylhistidine were decreased in response to taurine alone or in combination with CRF. Central taurine, alone and when co-administered with CRF, decreased isoleucine, phenylalanine, tyrosine and cysteine, but increased glycine concentrations in the brainstem, compared with saline and CRF groups. The results collectively indicate that central taurine attenuated CRF-induced hyperthermia and stress behaviors in neonatal chicks, and the mechanism likely involves the repartitioning of amino acids to different metabolic pathways. In particular, brain leucine, isoleucine, cysteine, glutamate and glycine may be mobilized to cope with acute stressors.

Vitamin B12 Attenuates Acute Pancreatitis by Suppressing Oxidative Stress and Improving Mitochondria Dysfunction via CBS/SIRT1 Pathway

Acute pancreatitis is an inflammatory disorder of the pancreas associated with substantial morbidity and mortality, which is characterized by a rapid depletion of glutathione (GSH). Cysthionine-β-synthase (CBS) is a key coenzyme in GSH synthesis, and its deficiency is related to a variety of clinical diseases. However, whether CBS is involved in the pathogenesis of acute pancreatitis remains unclear. First, we found that CBS was downregulated in both in vivo and in vitro AP models. The pancreatic damage and acinar cell necrosis related to CBS deficiency were significantly improved by VB 12, which stimulated clearance of reactive oxygen species (ROS) by conserving GSH. Furthermore, EX-527 (a specific inhibitor of SIRT1) exposure counteracted the protective effect of VB 12 by promoting oxidative stress and aggravating mitochondrial damage without influencing CBS, indicating that vitamin B₁₂ regulates SIRT1 to improve pancreatical damage by activating CBS. In conclusion, we found that VB 12 protected acute pancreatitis associated with oxidative stress via CBS/SIRT1 pathway.

Zinc oxide nanosphere for hydrogen sulfide scavenging and ferroptosis of colorectal cancer

Background

Colorectal cancer is a common malignancy occurring in the digestive system and ranks second in cancer mortality worldwide. In colorectal cancer, hydrogen sulfide (H₂S) is selectively upregulated, resulting in the further exacerbation of the disease. Therefore, the clearance of H₂S and the regulation of the enzymes on the H₂S pathways are of great significance for colorectal cancer therapy.

Methods

Here, we investigated the H₂S content in various clinical tumor tissues from patients and confirmed that overproduced concentration of H₂S in colorectal cancer. Accordingly, we developed an H₂S-responsive nanoplatform based on zinc oxide coated virus-like silica nanoparticles (VZnO) for the therapy of colorectal cancer.

Results

Owing to its excellent H₂S scavenging ability, VZnO could effectively reduce H₂S content in colorectal cancer to prohibit the growth of CT26 and HCT116 colorectal cancer cells. Moreover, the removal of H₂S in colorectal cancer also leads to tumor inhibition through activating ferroptosis, a non-apoptotic form of cell death. The biosafety-related toxicological and pathological analysis confirmed the low toxicity and high safety of VZnO in colorectal cancer treatment. Furthermore, as an H₂S-responsible nanosystem, VZnO appears to have no therapeutic effect on other non H₂S rich cancers, such as the 4T1 breast cancer model.

Conclusions

We anticipate that the H₂S-depletion-induced ferroptosis strategy using zinc oxide-based nanomaterials would provide insights in designing nanomedicines for colorectal cancer-target theranostics and may offer clinical promise.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01069-y.

Identifying a Ferroptosis-Related Gene Signature for Predicting Biochemical Recurrence of Prostate Cancer

Ferroptosis induced by lipid peroxidation is closely related to cancer biology. Prostate cancer (PCa) is not only a malignant tumor but also a lipid metabolic disease. Previous studies have identified ferroptosis as an important pathophysiological pathway in PCa development and treatment, but its role in the prognosis of PCa is less well known. In this study, we constructed a nine-ferroptosis-related gene risk model that demonstrated strong prognostic and therapeutic predictive power. The higher risk score calculated by the model was significantly associated with a higher ferroptosis potential index, higher Ki67 expression, higher immune infiltration, higher probability of biochemical recurrence, worse clinicopathological characteristics, and worse response to chemotherapy and antiandrogen therapy in PCa. The mechanisms identified by the gene set enrichment analysis suggested that this signature can accurately distinguish high- and low-risk populations, which is possibly closely related to variations in steroid hormone secretion, regulation of endocrine processes, positive regulation of humoral immune response, and androgen response. Results of this study were confirmed in two independent PCa cohorts, namely, The Cancer Genome Atlas cohort and the MSK-IMPACT Clinical Sequencing Cohort, which contributed to the body of scientific evidence for the prediction of biochemical recurrence in patients with PCa. In addition, as the main components of this signature, the effects of the AIFM2 and NFS1 genes on ferroptosis were evaluated and verified by in vivo and in vitro experiments, respectively. The above findings provided new insights and presented potential clinical applications of ferroptosis in PCa.

Hypoxia inducible lncRNA-CBSLR modulates ferroptosis through m6A-YTHDF2-dependent modulation of CBS in gastric cancer

•

1. The hypoxic microenvironment is a common hallmark of solid tumors and is strongly associated with therapy resistance and poor prognosis.

•

2. CBSLR, a long noncoding RNA transactivated by HIF-1α, is upregulated in GC and associated with poor prognosis.

•

3. CBSLR inhibition induces ferroptosis under hypoxic conditions and contributes to chemoresistance.

•

4. lncRNA-CBSLR recruits YTHDF2 protein and CBS mRNA to form CBSLR/ YTHDF2/CBS complex, which in turn decreases CBS mRNA stability in an m6A dependent manner.

•

5. CBSLR/CBS inhibits ferroptosis by modulating ACSL4 methylation to be polyubiquitinated.

Introduction

Tumors are usually refractory to anti-cancer therapeutics under hypoxic conditions. However, the underlying molecular mechanism remains to be elucidated.

Objectives

Our study intended to identify hypoxia inducible lncRNAs and their biological function in gastric cancer (GC).

Methods

Differentially expressed lncRNAs were determined by microarray analysis between GC cells exposed to hypoxia (1% O₂) and normoxia (21% O₂) for 24 h. The expression level of CBSLR was manipulated in several GC cell lines to perform molecular and biological analyses both in vitro and in vivo.

Results

We identified a hypoxia-induced lncRNA-CBSLR that protected GC cells from ferroptosis, leading to chem-resistance. Mechanically, CBSLR interacted with YTHDF2 to form a CBSLR/YTHDF2/CBS signaling axis that decreased the stability of CBS mRNA by enhancing the binding of YTHDF2 with the m6A-modified coding sequence (CDS) of CBS mRNA. Furthermore, under decreased CBS levels, the methylation of the ACSL4 protein was reduced, leading to protein polyubiquitination and degradation of ACSL4. This, in turn, decreased the pro-ferroptosis phosphatidylethanolamine (PE) (18:0/20:4) and PE (18:0/22:4) content and contributed to ferroptosis resistance. Notably, CBSLR is upregulated, whereas CBS is downregulated in GC tissues compared to matched normal tissues; and GC patients with high CBSLR/low CBS levels have a worse clinical outcome and a poorer response to chemotherapy.

Conclusion

Our study reveals a novel mechanism in how HIF1α/CBSLR modulates ferroptosis/chemoresistance in GC, illuminating potential therapeutic targets for refractory hypoxic tumors.

Ferroptosis-related gene signature associates with immunity and predicts prognosis accurately in patients with osteosarcoma

Osteosarcoma has been the most common malignant bone tumor in children and adolescents, while the 5‐y survival of osteosarcoma patients gained no significant improvement over the past decades. This study aimed to explore the role of ferroptosis‐related genes (FRGs) in the development and prognosis of osteosarcoma. The datasets of osteosarcoma patients including RNA sequencing data and clinical information were acquired from the TRGET and Gene Expression Omnibus (GEO) databases. The identification of molecular subgroups with different FRG expression patterns was achieved through nonnegative matrix factorization (NMF) clustering. The prognostic model was constructed using the least absolute shrinkage and selection operator (LASSO) algorithm and multivariate Cox regression analysis. The ESTIMATE algorithm was applied for determining the stromal score, immune score, ESTIMA score, and tumor purity of osteosarcoma patients. Functional analyses including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, Gene Set Enrichment Analysis (GSEA), and Gene Set Variation Analysis (GSVA) were conducted to explore the underlying mechanisms in the development and prognosis of osteosarcoma. Two molecular subgroups with different FRGs expression patterns were identified. The molecular subgroups with higher immune score and more active immune status showed better prognostic survival. On the basis of FRGs, a prognostic model and a nomogram integrating clinical characteristics were constructed and their prediction efficiency for osteosarcoma prognosis were well validated. Gene functional enrichment analysis showed that these differentially expressed FRGs were mainly enriched in immunity‐related signaling pathways, indicating that FRGs may affect the development and prognosis of osteosarcoma by regulating the immune microenvironment. The expression profiles of FRGs were closely related to the immunity status and prognostic survival of osteosarcoma patients. The interaction between ferroptosis and immunity in the development of osteosarcoma could provide a new insight into the exploration of molecular mechanisms and targeted therapies of osteosarcoma patients.

Low CBS expression can identify patients who benefit from adjuvant chemotherapy in gastric cancer

Aim: To explore the clinical significance of Cystathionine beta-synthase (CBS) expression in gastric cancer (GC).Research design and methods: CBS expression and clinicopathological/follow-up information of patients with gastric cancer undergoing operation were collected from The Cancer Genome Atlas (TCGA) database. The association of CBS expression with patients' overall survival (OS) was determined in the entire cohort and different subgroups. Validation was performed in two external cohorts from NCBI Gene Expression Omnibus (GEO) database. The estimated drug response of the tumors with different CBS expressions was characterized. The potential CBS-related cellular pathways in chemoresistance were explored.Results: High CBS was associated with poor OS in patients receiving adjuvant chemotherapy (ACT) but not those without ACT. And ACT was associated with favorable OS in patients with low CBS expression but not those with high CBS expression. The results were verified in two external cohorts. Drug response prediction suggested that patients with low CBS expression showed high sensitivity to 5-Fluorouracil. Gene Set Enrichment Analysis (GSEA) suggested that CBS might contribute to GC chemoresistance via modulating many cellular pathways, including down-regulating apoptosis and P53 pathways while up-regulating DNA repair pathway.Conclusion: Low CBS expression can predict the benefit from ACT in GC.

Research progress of hydrogen sulfide in Alzheimer's disease from laboratory to hospital: a narrative review

Alzheimer's disease is a neurodegenerative disease that mainly occurs in old age and early stages. Its main manifestations are memory impairment, aphasia, apraxia, loss of identity, abstract thinking and impairment of computing power, personality and behavior changes, etc. At present, the treatment of Alzheimer's disease only stays on reducing the disease and delaying the development, which is also a difficult problem to overcome in clinical practice. Hydrogen sulfide, as a third gaseous signal molecule after carbon monoxide and nitrogen monoxide, has become very popular in recent years. It shows very promising prospects in the Alzheimer's disease model. It can protect the nerve function and prevent the progress of the disease by affecting the amyloid precursor protein metabolism, anti-apoptosis, anti-inflammatory, and antioxidant pathways. Therefore, this article summarizes the relevant basic and clinical research of hydrogen sulfide in Alzheimer's disease, and discusses its progress and findings and mechanism characteristics.

The Role of H2S in the Gastrointestinal Tract and Microbiota

The pathways and mechanisms of the production of H₂S in the gastrointestinal tract are briefly described, including endogenous H₂S produced by the organism and H₂S from microorganisms in the gastrointestinal tract. In addition, the physiological regulatory functions of H₂S on gastrointestinal motility, sensation, secretion and absorption, endocrine system, proliferation and differentiation of stem cells, and the possible mechanisms involved are introduced. In view of the complexity of biosynthesis, physiological roles, and the mechanism of H₂S, this chapter focuses on the interactions and dynamic balance among H₂S, gastrointestinal microorganisms, and the host. Finally, we focus on some clinical gastrointestinal diseases, such as inflammatory bowel disease, colorectal cancer, functional gastrointestinal disease, which might occur or develop when the above balance is broken. Pharmacological regulation of H₂S or the intestinal microorganisms related to H₂S might provide new therapeutic approaches for some gastrointestinal diseases.

Proteomic profile of the effects of low-dose bisphenol A on zebrafish ovaries

Human exposure to bisphenol-A (BPA) is largely unavoidable because BPA is an environmental contaminant found in soil, water, food and indoor dust. The safety of authorized BPA amounts in consumer products is under question because new studies have reported adverse effects of BPA at doses far below that previously established by the NOAEL (50 μg/kg per day). To protect public health, the consequences of low-dose BPA exposure in different organs and organismal functions must be further studied to generate relevant data. This study attempted to investigate the effects and potential molecular mechanisms of short-term exposure to 1 μg/L BPA on zebrafish ovarian follicular development. We observed only minor changes at the histopathological level with a small (3 %) increase in follicular atresia. However, a shotgun proteomics approach indicated deep alterations in BPA-exposed ovarian cells, including induction of the oxidative stress response, metabolic shifts and degradome perturbations, which could drive oocytes towards premature maturation. Based on these results, it could be suggested that inadvertent exposure to small concentrations of BPA on a continuous basis causes alteration in biological processes that are essential for healthy reproduction.

Highly recurrent CBS epimutations in gastric cancer CpG island methylator phenotypes and inflammation

Background

CIMP (CpG island methylator phenotype) is an epigenetic molecular subtype, observed in multiple malignancies and associated with the epigenetic silencing of tumor suppressors. Currently, for most cancers including gastric cancer (GC), mechanisms underlying CIMP remain poorly understood. We sought to discover molecular contributors to CIMP in GC, by performing global DNA methylation, gene expression, and proteomics profiling across 14 gastric cell lines, followed by similar integrative analysis in 50 GC cell lines and 467 primary GCs.

Results

We identify the cystathionine beta-synthase enzyme (CBS) as a highly recurrent target of epigenetic silencing in CIMP GC. Likewise, we show that CBS epimutations are significantly associated with CIMP in various other cancers, occurring even in premalignant gastroesophageal conditions and longitudinally linked to clinical persistence. Of note, CRISPR deletion of CBS in normal gastric epithelial cells induces widespread DNA methylation changes that overlap with primary GC CIMP patterns. Reflecting its metabolic role as a gatekeeper interlinking the methionine and homocysteine cycles, CBS loss in vitro also causes reductions in the anti-inflammatory gasotransmitter hydrogen sulfide (H₂S), with concomitant increase in NF-κB activity. In a murine genetic model of CBS deficiency, preliminary data indicate upregulated immune-mediated transcriptional signatures in the stomach.

Conclusions

Our results implicate CBS as a bi-faceted modifier of aberrant DNA methylation and inflammation in GC and highlights H₂S donors as a potential new therapy for CBS-silenced lesions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13059-021-02375-2.

Letrozole-Induced Polycystic Ovary Syndrome Attenuates Cystathionine-β Synthase mRNA and Protein Abundance in the Ovaries of Female Sprague Dawley Rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects 10% of reproductive-aged women and leads to hyperandrogenism, anovulation, and infertility. PCOS has been associated with elevated serum homocysteine as well as altered methylation status; however, characterization of one-carbon metabolism (OCM) in PCOS remains incomplete.

OBJECTIVES

The aim of our research was to assess OCM in a letrozole-induced Sprague Dawley rat model of PCOS.

METHODS

Five-week-old female rats (n = 36) were randomly assigned to letrozole [0.9 mg/kg body weight (BW)] treatment or vehicle (carboxymethylcellulose) control that was administered via subcutaneously implanted slow-release pellets every 30 d. For both treatment groups, 12 rats were randomly assigned to be euthanized during proestrus at one of the following time points: 8, 16, or 24 wk of age. Daily BW was measured and estrous cyclicity was monitored during the last 30 d of the experimental period. Ovaries were collected to assess mRNA and protein abundance of OCM enzymes.

RESULTS

Letrozole-induced rats exhibited 1.9-fold higher cumulative BW gain compared with control rats across all age groups (P < 0.0001). Letrozole reduced the time spent at proestrus (P = 0.0001) and increased time in metestrus (P < 0.0001) of the estrous cycle. Cystathionine β-synthase (Cbs) mRNA abundance was reduced in the letrozole-induced rats at 16 (59%; P < 0.05) and 24 (77%; P < 0.01) wk of age. In addition, CBS protein abundance was 32% lower in 8-wk-old letrozole-induced rats (P = 0.02). Interestingly, betaine-homocysteine S-methyltransferase mRNA abundance increased as a function of age in letrozole-induced rats (P = 0.03).

CONCLUSION

These data demonstrate that letrozole-induced PCOS Sprague Dawley rats temporally decrease the ovarian abundance of Cbs mRNA and protein in the early stages of PCOS.

Hydrogen sulfide in longevity and pathologies: Inconsistency is malodorous

Hydrogen sulfide (H₂S) is one of the biologically active gases (gasotransmitters), which plays an important role in various physiological processes and aging. Its production in the course of methionine and cysteine catabolism and its degradation are finely balanced, and impairment of H₂S homeostasis is associated with various pathologies. Despite the strong geroprotective action of exogenous H₂S in C. elegans, there are controversial effects of hydrogen sulfide and its donors on longevity in other models, as well as on stress resistance, age-related pathologies and aging processes, including regulation of senescence-associated secretory phenotype (SASP) and senescent cell anti-apoptotic pathways (SCAPs). Here we discuss that the translation potential of H₂S as a geroprotective compound is influenced by a multiplicity of its molecular targets, pleiotropic biological effects, and the overlapping ranges of toxic and beneficial doses. We also consider the challenges of the targeted delivery of H₂S at the required dose. Along with this, the complexity of determining the natural levels of H₂S in animal and human organs and their ambiguous correlations with longevity are reviewed.

Moonlighting Metabolic Enzymes in Cancer: New Perspectives on the Redox Code

Significance: Metabolic reprogramming is considered to be a critical adaptive biological event that fulfills the energy and biomass demands for cancer cells. One hallmark of metabolic reprogramming is reduced oxidative phosphorylation and enhanced aerobic glycolysis. Such metabolic abnormalities contribute to the accumulation of reactive oxygen species (ROS), the by-products of metabolic pathways. Emerging evidence suggests that ROS can in turn directly or indirectly affect the expression, activity, or subcellular localization of metabolic enzymes, contributing to the moonlighting functions outside of their primary roles. This review summarizes the multifunctions of metabolic enzymes and the involved redox modification patterns, which further reveal the inherent connection between metabolism and cellular redox state. Recent Advances: These noncanonical functions of metabolic enzymes involve the regulation of epigenetic modifications, gene transcription, post-translational modification, cellular antioxidant capacity, and many other fundamental cellular events. The multifunctional properties of metabolic enzymes further expand the metabolic dependencies of cancer cells, and confer cancer cells with a means of adapting to diverse environmental stimuli. Critical Issues: Deciphering the redox-manipulated mechanisms with specific emphasis on the moonlighting function of metabolic enzymes is important for clarifying the pertinence between metabolism and redox processes. Future Directions: Investigation of the redox-regulated moonlighting functions of metabolic enzymes will shed new lights into the mechanism by which metabolic enzymes gain noncanonical functions, and yield new insights into the development of novel therapeutic strategies for cancer treatment by targeting metabolic-redox abnormalities. Antioxid. Redox Signal. 34, 979-1003.

Transcriptomic Analysis of the Mechanisms for Alleviating Psoriatic Dermatitis Using Taodan Granules in an Imiquimod-Induced Psoriasis-like Mouse Model

Taodan granules (TDGs) are clinically efficacious for treating psoriasis, buttheir specific mechanisms of action are unclear. In this study, we determined the concentrations of tanshinone IIA and curcumol using high-performance liquid chromatography (HPLC) to establish quality control parameters for assessing the mechanism of TDGs in treating psoriasis. Thereafter, a mouse model of psoriasis was treated with TDGs. TDGs attenuated imiquimod-induced typical erythema, scales, and thickening of the back and ear lesions in the psoriatic mouse model. Furthermore, PCNA and Ki67-positive cells were reduced in the epidermis of psoriatic lesions following TDG treatment. Finally, the sequencing results were verified using a multitude of methods, and the mechanism of action of TDGs against psoriasis was found to be via the upregulation of metabolic signaling pathways such as the Gly-Ser-Thr axis, the downregulation of immune and inflammatory pathways, and the decrease in Rac2 and Arhgdib concentrations. Overall, this study clarified the mechanism of TDG treatment for psoriasis and provided evidence for its clinical application.

Therapeutic potential of endogenous hydrogen sulfide inhibition in breast cancer (Review)

Hydrogen sulfide (H₂S), the third gas signal molecule, is associated with the modulation of various physiological and pathological processes. Recent studies have reevealed that endogenous H₂S may promote proliferation, induce angiogenesis and inhibit apoptosis, thereby stimulating oncogenesis. Conversely, decreased endogenous H₂S release suppresses growth of various tumors including breast cancer. This observation suggests an alternative tumor therapy strategy by inhibiting H₂S-producing enzymes to reduce the release of endogenous H₂S. Breast cancer is the most common type of cancer in women. Due to the lack of approved targeted therapy, its recurrence and metastasis still affect its clinical treatment. In recent years, significant progress has been made in the control of breast cancer by using inhibitors on H₂S-producing enzymes. This review summarized the roles of endogenous H₂S-producing enzymes in breast cancer and the effects of the enzyme inhibitors on anticancer and anti-metastasis, with the aim of providing new insights for the treatment of breast cancer.

Genetic and molecular biology of autism spectrum disorder among Middle East population: a review

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disease, characterized by impaired social communication, executive dysfunction, and abnormal perceptual processing. It is more frequent among males. All of these clinical manifestations are associated with atypical neural development. Various genetic and environmental risk factors are involved in the etiology of autism. Genetic assessment is essential for the early detection and intervention which can improve social communications and reduce abnormal behaviors. Although, there is a noticeable ASD incidence in Middle East countries, there is still a lack of knowledge about the genetic and molecular biology of ASD among this population to introduce efficient diagnostic and prognostic methods.

MAIN BODY

In the present review, we have summarized all of the genes which have been associated with ASD progression among Middle East population. We have also categorized the reported genes based on their cell and molecular functions.

CONCLUSIONS

This review clarifies the genetic and molecular biology of ASD among Middle East population and paves the way of introducing an efficient population based panel of genetic markers for the early detection and management of ASD in Middle East countries.