Sphingolipid metabolism in cancer signalling and therapy

SPHK1/S1PR1/PPAR-α axis restores TJs between uroepithelium providing new ideas for IC/BPS treatment

Interstitial cystitis/bladder pain syndrome (IC/BPS) represents a chronic, aseptic inflammatory bladder condition with an unclear etiology and few therapeutic options. A composite barrier structure composed of the uroepithelium and glycosaminoglycan layer forms on the bladder's inner surface to block urine and other harmful substances. Dysfunction of this barrier may initiate the pathogenesis of IC/BPS. Sphingosine-1-phosphate (S1P) plays a crucial role in forming tight junctions. Perfusion of S1P into the bladder restored uroepithelial tight junctions in mice with cyclophosphamide-induced acute cystitis and ameliorated symptoms of the lower urinary tract. Mice lacking sphingosine kinase 1 (SHPK1) exhibited more severe bladder injuries and dysfunction. Concurrent in vitro experiments elucidated S1P's protective effects and its role as a primary messenger through SPHK1 and S1P receptor 1 (S1PR1) knockdown. This study identifies a novel mechanism whereby S1P binding to S1PR1 activates the PPAR-α pathway, thereby enhancing cholesterol transport and restoring tight junctions between uroepithelial cells. These findings elucidate the regulatory role of S1P in the bladder epithelial barrier and highlight a promising therapeutic target for IC/BPS.

The fruit of Rosa odorata sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils attenuates chronic atrophic gastritis induced by MNNG and its potential mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Rosa odorata Sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils is a commonly utilized traditional medicine among the Yi nationality, also known as "Gugongguo", for the treatment of gastrointestinal disorders. Previous studies have indicated that the extract of Rosa odorata sweet var. gigantea (FOE) fruit has demonstrated a protective effect on the stomach; however, its impact on chronic atrophic gastritis (CAG) with severe disease remains unknown.

AIM OF THE STUDY

This study aimed to investigate the impact of FOE on CAG and its underlying mechanisms both in vitro and in vivo.

MATERIALS AND METHODS

By employing Ultra Performance Liquid Chromatography/Quadrupole-Time of Flight Mass Spectrometry (UPLC-QTOF-MS/MS) and network pharmacology, the primary active compounds and action targets of FOE were identified. In vitro, the impact of FOE on CAG was investigated through scratch, migration, and invasion assays. Subsequently, guided by network pharmacology, EMT and TGF-β signaling pathway-related proteins were assessed using Western blot and immunofluorescence experiments. Additionally, an in vivo CAG rat model was established to validate the effects of FOE and confirm its mechanism of action through hematoxylin-eosin (H&E), immunohistochemistry, Western blot, as well as untargeted metabolomics analysis of rat serum. It was observed that FOE inhibited scratch healing abilities, migration, invasion capabilities, as well as the expression of EMT-related proteins (E-cadherin, N-cadherin, Snail, Vimentin) in CAG model cells (MC cells), providing initial evidence for its efficacy.

RESULTS

Through the analysis of UPLC-QTOF-MS/MS, a total of 51 major compounds were identified in the FOE. Subsequent network pharmacological analysis suggested that FOE may regulate Epithelial mesenchymal transition (EMT) through the transforming growth factor β (TGF-β) pathway. Furthermore, experimental verification demonstrated that FOE inhibited the protein expression of TGF-β1 and its downstream protein Smad2/3 in vitro. In vivo findings also indicated similar mechanisms in MC cells, suggesting a reversal of the CAG process and significant inhibition of EMT and TGF-β signaling pathways. Additionally, untargeted metabolomics of rat serum confirmed the therapeutic effect of FOE on CAG and predicted its potential involvement in the arachidonic acid metabolic pathway.

CONCLUSION

This study initially demonstrated that FOE effectively reverses the process of EMT through the TGF-β1/Smad2/3 signaling pathway, thereby providing a therapeutic benefit for CAG.

Metabolomics Signatures of Exposure to Ambient Air Pollution: A Large-Scale Metabolome-Wide Association Study in the Cancer Prevention Study-II Nutrition Cohort

Existing air pollution metabolomics studies showed inconsistent results, often limited by small sample size and individual air pollutants effects. We conducted a metabolome-wide association study among 1096 women (68.2 ± 5.7 years) who provided blood samples (1998-2001) within the Cancer Prevention Study-II Nutrition Cohort. Annual average individual exposures to particulate matter, nitrogen dioxide, ozone, sulfur dioxide, and carbon monoxide in the year of blood draw were used. Metabolomics profiling was conducted on serum samples by Metabolon. We evaluated the individual air pollutants effects using multiple linear regression and the mixture effect using quantile g-computation, adjusting for confounders and false discovery rate (FDR). Ninety-five metabolites were significantly associated with at least one air pollutant or mixture (FDR < 0.05). These metabolites were enriched in pathways related to oxidative stress, systemic inflammation, energy metabolism, signals transduction, nucleic acid damage and repair, and xenobiotics. Sixty metabolites were confirmed with level 1 or 2 evidence, among which 21 have been previously linked to air pollution exposure, including taurine, creatinine, and sebacate. Overall, our results replicate prior findings in a large sample and provide novel insights into biological responses to long-term air pollution exposure using mixture analysis.

The roles of KRAS in cancer metabolism, tumor microenvironment and clinical therapy

KRAS is one of the most mutated genes, driving alternations in metabolic pathways that include enhanced nutrient uptaking, increased glycolysis, elevated glutaminolysis, and heightened synthesis of fatty acids and nucleotides. However, the beyond mechanisms of KRAS-modulated cancer metabolisms remain incompletely understood. In this review, we aim to summarize current knowledge on KRAS-related metabolic alterations in cancer cells and explore the prevalence and significance of KRAS mutation in shaping the tumor microenvironment and influencing epigenetic modification via various molecular activities. Given that cancer cells rely on these metabolic changes to sustain cell growth and survival, targeting these processes may represent a promising therapeutic strategy for KRAS-driven cancers.

Bisphenol A exacerbates colorectal cancer progression through enhancing ceramide synthesis

Bisphenol A (BPA) is a typical environmental endocrine disruptor which have been broadly confirmed to be associated with malignant tumors, including colorectal cancer (CRC). Lipid metabolism reprogramming performed important biological effects in cancer progression. While the role of lipid metabolism in CRC progression upon BPA exposure remain elusive. Here, we found that BPA exposure enhanced de novo ceramide synthesis in vitro, along with upregulated ceramide synthase in high-BPA tumor tissue of CRC patients. Simultaneously, we demonstrated that BPA exposure exacerbated tumor biological behavior and epithelial mesenchymal transition (EMT), concurrent with elevated EMT expression of CRC tissue in high BPA group. Subsequently, the inhibition of ceramide synthase and pharmacological stimulation experiments revealed that ceramide accumulation activated EMT and exacerbated CRC progression, including Cer (d18:1/16:0) and Cer (d18:1/24:1). Collectively our findings elucidated the pathogenesis of ceramide accumulation escalating tumor progression under environmental BPA exposure, providing a strong basis for further investigation of dysregulated ceramide metabolism to boost tumor development and avoid metastatic relapse.

Serum and Plasma Sphingolipids as Biomarkers of Anthracycline-Induced Cardiotoxicity

Although effective as a chemotherapy, the utility of Doxorubicin (Dox) is hampered by cardiotoxicity. Despite this, the ability to predict and guide monitoring of patients receiving Dox or other anthracyclines is hampered by a lack of effective biomarkers to identify susceptible patients, and to detect early signs of subclinical cardiotoxicity. Based on their well-established roles in the response to Dox and other chemotherapies, we performed a retrospective analysis of serum and plasma sphingolipids (SLs) from patients undergoing anthracycline-containing therapy, correlating with cardiac parameters assessed by echocardiography. Results showed there were substantial changes in both plasma and serum SL species during therapy including ceramide (Cer), deoxydihydroCer, and dihydrosphingosine with reversion towards baseline following treatment. Linear mixed-effects model analysis revealed that at baseline, a number of SLs correlated with adverse cardiac outcomes with serum sphingosine-1-phosphate (S1P) and dihydroS1P, and plasma Cer performing comparably to the prognostic value of pro-NT-BNP, an established biomarker of cardiotoxicity. Intriguingly, while pro-NT-BNP had no predictive value at mid- and post-therapy timepoints, serum S1P and dhS1P and plasma Cer levels showed correlation with adverse outcomes, particularly at the post-therapy timepoint. Finally, analysis of plasma and serum C16:C24- Cer ratios - previously reported as predictive of adverse cardiac outcomes - showed no correlation in the context of anthracycline treatment. Taken together, this pilot study provides supporting evidence that plasma and serum SLs may have benefit as both prognostic and diagnostic biomarkers for patients undergoing anthracycline-containing therapy. This suggests that diagnostic SL measurements - recently implemented for metabolic-associated cardiac disorders - could have wider utility.

Serum metabolomic profiling for predicting therapeutic response and toxicity in breast cancer neoadjuvant chemotherapy: a retrospective longitudinal study

BACKGROUND

Neoadjuvant chemotherapy (NACT) is the standard-of-care treatment for patients with locally advanced breast cancer (LABC), providing crucial benefits in tumor downstaging. Clinical parameters, such as molecular subtypes, influence the therapeutic impact of NACT. Moreover, severe adverse events delay the treatment process and reduce the effectiveness of therapy. Although metabolic changes during cancer treatment are crucial determinant factors in therapeutic responses and toxicities, related clinical research remains limited.

METHODS

One hundred paired blood samples were collected from 50 patients with LABC before and after a complete NACT treatment cycle. Untargeted metabolomics was used by liquid chromatography-mass spectrometry (LC-MS) to investigate the relationship between dynamically changing metabolites in serum and the responses and toxicities of NACT.

RESULTS

Firstly, we observed significant alterations in serum metabolite levels pre- and post-NACT, with a predominant enrichment in the sphingolipid and amino acid metabolism pathways. Second, pre-treatment serum metabolites successfully predicted the therapeutic response and hematotoxicities during NACT. In particular, molecular subtype variations in favorable treatment responses are linked to acyl carnitine levels. Finally, we discovered that the therapeutic effects of NACT could be attributed to essential amino acid metabolism.

CONCLUSION

This study elucidated the dynamic changes in metabolism during NACT treatment, providing a possibility for developing responsive metabolic signatures for personalized NACT treatment.

Anti-ceramide antibody and sphingosine-1-phosphate as potential biomarkers of unresectable non-small cell lung cancer

Objectives

Spingosine-1-phosphate (S1P) and ceramides are bioactive sphingolipids that influence cancer cell fate. Anti-ceramide antibodies might inhibit the effects of ceramide. The aim of this study was to assess the potential role of circulating S1P and anti-ceramide antibody as biomarkers in non-small cell lung cancer (NSCLC).

Methods

We recruited 66 subjects (34 controls and 32 patients with NSCLC). Patient history and clinical variables were taken from all participants. Venous blood samples were collected to evaluate plasma biomarkers. If bronchoscopy was performed, bronchial washing fluid (BWF) was also analyzed. We measured the levels of S1P and anti-ceramide antibody with ELISA.

Results

S1P levels were significantly higher in the NSCLC group (3770.99 ± 762.29 ng/mL vs. 366.53 ± 249.38 ng/mL, patients with NSCLC vs. controls, respectively, p < 0.001). Anti-ceramide antibody levels were significantly elevated in the NSCLC group (278.70 ± 19.26 ng/mL vs. 178.60 ± 18 ng/mL, patients with NSCLC vs. controls, respectively, p = 0.007). Age or BMI had no significant effect on anti-ceramide antibody or S1P levels. BWF samples had higher levels of anti-ceramide antibody (155.29 ± 27.58 ng/mL vs. 105.87 ± 9.99 ng/mL, patients with NSCLC vs. controls, respectively, p < 0.001). Overall survival (OS) was 13.36 months. OS was not affected by anti-ceramide antibody or S1P levels.

Conclusion

Higher levels of S1P and anti-ceramide antibody were associated with active cancer. These results suggest that sphingolipid alterations might be important features of NSCLC.

UV-aging process of titanium dioxide nanoparticles aggravates enterohepatic toxicity of bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate to zebrafish

The physicochemical characteristics of titanium dioxide nanoparticles (n-TiO2) may change during the aging process once discharged into aquatic environment. However, how the aging process affects their interactions with co-existing pollutants, as well as the joint toxicity has not been explored. This study investigated how UV-aging impacts n-TiO2 in aquatic environments and their interactions with bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), focusing on their joint toxicity in adult female zebrafish. UV-aging process significantly increased the specific area and hydrophobicity of n-TiO2, promoting the adsorption of TBPH. In vivo experiments revealed that aged n-TiO2 enhanced the bioaccumulation of TBPH in the liver and intestine, worsening hepatic steatosis and intestinal barrier damage. A combined analysis of hepatic lipidomic profiling and intestinal microbiota 16S rRNA sequencing revealed that co-exposure of aged n-TiO2 and TBPH altered gut microbial composition and abundances, facilitating the circulation of lipopolysaccharides (LPS) through the gut-liver axis. Subsequentially, the elevated LPS level in the liver activated the sphingolipid metabolic pathway, resulting in severer lipid metabolism disorders and hepatotoxicity. This study found that UV-aging increases the hydrophobicity and surface area of n-TiO2, enhancing their interaction with the TBPH, which leads to greater bioaccumulation and hepatoxicity through mechanisms involving changes in gut microbiomes and sphingolipid metabolism.

Machine learning approach in canine mammary tumour classification using rapid evaporative ionization mass spectrometry

Rapid evaporative ionization mass spectrometry (REIMS) coupled with a monopolar handpiece used for surgical resection and combined with chemometrics has been previously explored by our research group (Mangraviti et al. in Int J Mol Sci 23(18):10562, 2022) to identify several mammary gland pathologies. Here, the increased sample size allowed the construction of three statistical models to distinguish between benign and malignant canine mammary tumours (CMTs), facilitating a more in-depth investigation of changes in cellular metabolic phenotype during neoplastic transformation and biological behaviour. The results demonstrate that REIMS is effective in identifying neoplastic tissues with an accuracy of 97%, with differences in MS spectra characterized by the relative abundance of phospholipids compared to triglycerides more commonly identified in normal mammary glands. The increased rate of phospholipid synthesis represents an informative feature for tumour recognition, with phosphatidylcholine and phosphatidylethanolamine, the two major phospholipid species identified here together with sphingolipids, playing a crucial role in carcinogenesis. REIMS technology allowed the classification of different histotypes of benign CMTs with an accuracy score of 95%, distinguishing them from normal glands based on the increase in sphingolipids, glycolipids, phospholipids, and arachidonic acid, demonstrating the close association between cancer and inflammation. Finally, dysregulation of fatty acid metabolism with increased signalling for saturated, mono- and polyunsaturated fatty acids characterized the metabolic phenotype of neoplastic cells and their malignant transformation, supporting the increased formation of new organelles for cell division. Further investigations on a more significant number of tumour histotypes will allow for the creation of a more extensive database and lay the basis for how understanding metabolic alterations in the tumour microenvironment can improve surgical precision.

The influence of endothelial metabolic reprogramming on the tumor microenvironment

Endothelial cells (ECs) that line blood vessels act as gatekeepers and shape the metabolic environment of every organ system. In normal conditions, endothelial cells are relatively quiescent with organ-specific expression signatures and metabolic profiles. In cancer, ECs are metabolically reprogrammed to promote the formation of new blood vessels to fuel tumor growth and metastasis. In addition to EC's role on tumor cells, the tortuous tumor vasculature contributes to an immunosuppressive environment by limiting T lymphocyte infiltration and activity while also promoting the recruitment of other accessory pro-angiogenic immune cells. These elements aid in the metastatic spreading of cancer cells and contribute to therapeutic resistance. The concept of restoring a more stabilized vasculature in concert with cancer immunotherapy is emerging as a potential approach to overcoming barriers in cancer treatment. This review summarizes the metabolism of endothelial cells, their regulation of nutrient uptake and delivery, and their impact in shaping the tumor microenvironment and anti-tumor immunity. We highlight new therapeutic approaches that target the tumor vasculature and harness the immune response. Appreciating the integration of metabolic state and nutrient levels and the crosstalk among immune cells, tumor cells, and ECs in the TME may provide new avenues for therapeutic intervention.

Sphingosine-1-phosphate alleviates Sjögren's syndrome-like symptoms via inducing autophagy and regulating status of Treg cells in NOD mice

BACKGROUND

Sjögren' s syndrome (SS) is a chronic autoimmune disease that causes multiple lesions. Regulatory T (Treg) cells play an important role in the maintenance of immune homeostasis. Weakened Treg-cell-mediated immunosuppression may aggravate SS symptoms by inducing lymphocyte infiltration into the salivary glands. Although Treg cell egress from such glands requires sphingosine-1-phosphate (S1P), the specific effects of S1P on SS-like symptoms remain unclear.

AIMS

To examine the effect of S1P on SS-like symptoms and the crosstalk between such symptoms and autophagy in non-obese diabetic (NOD) mice.

METHODS

NOD mice were taken as SS model mice. Balb/c mice served as controls. Serum anti-SSA and anti-SSB antibodies were quantitated via ELISA. Submandibular gland tissues were subjected to haematoxylin-and-eosin staining, and extracts thereof to reverse transcription-polymerase chain reaction. The numbers of Treg cells; and the levels of cytokines, LC3, and SPHK1 were measured via flow cytometry (FCM). The Treg immunosuppression capacity was assessed in co-culture experiments.

RESULT

Compared to untreated NOD mice, mice treated with S1P exhibited milder disease, and higher numbers of functional Treg cells. FCM revealed that S1P restored LC3 expression in Treg cells, but had little effect on the LC3 levels of Teff cells. RT-PCR showed that S1P increased the expression levels of mRNAs encoding Foxp-3, SPHK1, S1PR1, and LC3 in submandibular glands (SMGs). After administration of PF-543, the disease became aggravated; lymphocyte infiltration into SMGs increased and LC3 expression fell.

CONCLUSION

S1P therapy alleviated SS-like symptoms in NOD mice by increasing the number of Treg cells, by restoring Treg cell function, and by positively regulating autophagy via crosstalk. Such therapy may be a new and valuable SS treatment option.

Loss of SUR2 alters the composition of ceramides and shortens chronological lifespan of Saccharomyces cerevisiae

Sphingolipids are crucial components of cell membranes and serve as important signaling molecules. Ceramide, as the central hub of sphingolipid metabolism, plays a significant role in various biological processes, including the cell cycle, apoptosis, and cellular aging. Alterations in sphingolipid metabolism are implicated in cellular aging, however, the specific sphingolipid components and intrinsic mechanisms that mediate this process remain largely uncharacterized. In this study, we established a targeted sphingolipidomics approach and employed LC-MS/MS to quantitatively analyze changes in ceramide levels during chronological aging and in sur2Δ strains, aiming to elucidate the role of ceramides in regulating chronological lifespan. Our study revealed that in Saccharomyces cerevisiae, the C4 hydroxylase Sur2 and its product, phytoceramide, increase during chronological aging. While the loss of SUR2 function leads to a near-complete loss of phytoceramides and an accumulation of dihydroceramides, resulting in a significant reduction of total ceramide content to about half of that in wild-type cells. This ceramide profile alteration impairs both mitochondrial morphology and function, ultimately shortening the chronological lifespan. The knockout of SIT4 restores mitochondrial morphology and function, and rescues the chronological lifespan of SUR2-deficient yeast. Our findings highlight the critical role of dihydroceramide and phytoceramide in chronological aging in yeast and suggest that an imbalance between these two metabolites may trigger downstream ceramide signaling pathways. These insights could help elucidate potential mechanisms through which ceramide imbalance contributes to disease development in higher organisms.

Structure Revision of Halisphingosine A via Total Synthesis and Bioactivity Studies

Sphingoid bases are important bioactive lipids found in a variety of organisms, serving as the backbone of sphingolipids, which regulate essential physiological processes. Here we describe the total synthesis and structure revision of halisphingosine A, a sphingoid base initially isolated from marine sponges. To address inconsistencies in the NMR interpretation of this natural product, we developed a synthetic route involving a late-stage enantioselective Henry reaction that allows access to multiple stereoisomers of the proposed halisphingosine A core structure. Our library of 32 fully characterized synthetic stereoisomers enabled us to rectify the structure of halisphingosine A as (2R,3R,8R,Z)-2-aminooctadec-9-ene-1,3,8-triol, and to pursue further structure-activity relation (SAR) studies regarding their antimicrobial and cytotoxic potential. In summary, our study offers a yet unreported compound library along with validated analytical datasets of marine sphingoid base derivatives, which significantly affects future ecometabolomic marine research and will facilitate the identification of inhibitors of sphingolipid metabolism or antagonists of sphingolipid base-sensing receptors.

The palmitoyl-CoA ligase Fum16 is part of a Fusarium verticillioides fumonisin subcluster involved in self-protection

Fusarium verticillioides produces the mycotoxin fumonisin B1 (FB1), which disrupts sphingolipid biosynthesis by inhibiting ceramide synthase and affects the health of plants, animals, and humans. The means by which F. verticillioides protects itself from its own mycotoxin are not completely understood. Some fumonisin (FUM) cluster genes do not contribute to the biosynthesis of the compound, but their function has remained enigmatic. Recently, we showed that FUM17, FUM18, and FUM19 encode two ceramide synthases and an ATP-binding cassette transporter, respectively, which play a role in antagonizing the toxicity mediated by FB1. In the present work, we uncovered functions of two adjacent genes, FUM15 and FUM16. Using homologous and heterologous expression systems, in F. verticillioides and Saccharomyces cerevisiae, respectively, we provide evidence that both contribute to protection against FB1. Our data indicate a potential role for the P450 monooxygenase Fum15 in the modification and detoxification of FB1 since the deletion and overexpression of the respective gene affected extracellular FB1 levels in both hosts. Furthermore, relative quantification of ceramide intermediates and an in vitro enzyme assay revealed that Fum16 is a functional palmitoyl-CoA ligase. It co-localizes together with the ceramide synthase Fum18 to the endoplasmic reticulum, where they contribute to sphingolipid biosynthesis. Thereby, FUM15-19 constitute a subcluster within the FUM biosynthetic gene cluster dedicated to the fungal self-protection against FB1.IMPORTANCEThe study identifies a five-gene FUM subcluster (FUM15-19) in Fusarium verticillioides involved in self-protection against FB1. FUM16 (palmitoyl-CoA ligase), FUM17, and FUM18 (ceramide synthases) enzymatically supplement ceramide biosynthesis, while FUM19 (ATP-binding cassette transporter) acts as a repressor of the FUM cluster. The evolutionary conservation of FUM15 (P450 monooxygenase) in Fusarium and Aspergillus FUM clusters is discussed, and its effect on extracellular FB1 levels in both native (F. verticillioides) and heterologous (Saccharomyces cerevisiae) hosts is highlighted. These findings enhance our understanding of mycotoxin self-protection mechanisms and could inform strategies for predicting biological activity of unknown secondary metabolites, managing mycotoxin contamination, and developing resistant crop cultivars.

Bile molecular landscape provides pathological insight and classifies signatures predictive of carcinoma of the gall bladder

Carcinoma of the gall bladder (CAGB) has a poor prognosis. Molecular analysis of bile could classify indicators of CAGB. Bile samples (n = 87; training cohort) were screened for proteomics and metabolomics signatures of cancer detection. In bile, CAGB showed distinct proteomic (217 upregulated, 258 downregulated) and metabolomic phenotypes (111 upregulated, 505 downregulated, p < 0.05, fold change > 1.5, false discovery rate <0.01) linked to significantly increased inflammation (coagulation, arachidonic acid, bile acid) and alternate energy pathways (pentose-phosphate pathway, amino acids, lipid metabolism); and decreased glycolysis, cholesterol metabolism, PPAR, RAS, and RAP1 signaling, oxidative phosphorylation, and others compared to gallstone or healthy controls (p < 0.05). Bile proteins/metabolites signatures showed significant correlation (r 2  > 0.5, p < 0.05) with clinical parameters. Metabolite/protein signature-based probability of detection for CAGB (cancer) was >90% (p < 0.05), with area under the receiver operating characteristic curve >0.94. Validation of the top four metabolites-toluene, 5,6-DHET, creatine, and phenylacetaldehyde-in separate cohorts (n = 80; bile [T1] and paired plasma [T2]) showed accuracy (99%) and sensitivity/specificity (>98%) for CAGB detection. Tissue validation showed bile 5,6-DHET positively correlated with tissue PCNA (proliferation), and caspase-3 linked to cancer development (r 2 >0.5, p < 0.05). In conclusion, the bile molecular landscape provides critical molecular understanding and outlines metabolomic indicator panels for early CAGB detection.

Szabo B, Kothalawala RC, Szekelyhidi V, Nagy P, Varga Z, Panyi G, Zakany F. Inhibition of the HV1 voltage-gated proton channel compromises the viability of human polarized macrophages in a polarization- and ceramide-dependent manner

The human voltage-gated proton channel (HV1) provides an efficient proton extrusion pathway from the cytoplasm contributing to the intracellular pH regulation and the oxidative burst. Although its pharmacological inhibition was previously shown to induce cell death in various cell types, no such effects have been examined in polarized macrophages albeit HV1 was suggested to play important roles in these cells. This study highlights that 5-chloro-2-guanidinobenzimidazole (ClGBI), the most widely applied HV1 inhibitor, reduces the viability of human THP-1-derived polarized macrophages at biologically relevant doses with M1 macrophages being the most, and M2 cells the least sensitive to this compound. ClGBI may exert this effect principally by blocking HV1 since the sensitivity of polarized macrophages correlates well with their HV1 expression levels; inhibitors of other macrophage ion channels that may be susceptible for off-target ClGBI effects cause no viability reductions; and Zn2+, another non-specific HV1 blocker, exerts similar effects. As a potential mechanism behind the ClGBI-induced cell death, we identify a complex pH dysregulation involving acidification of the cytoplasm and alkalinization of the lysosomes, which eventually result in membrane ceramide accumulation. Furthermore, ClGBI effects are alleviated by ARC39, a selective acid sphingomyelinase inhibitor supporting the unequivocal significance of ceramide accumulation in the process. Altogether, our results suggest that HV1 inhibition leads to cellular toxicity in polarized macrophages in a polarization-dependent manner, which occurs due to a pH dysregulation and concomitant ceramide overproduction mainly depending on the activity of acid sphingomyelinase. The reduced macrophage viability and plausible concomitant changes in homeostatic M1-M2 balance could contribute to both the therapeutic and potential side effects of HV1 inhibitors that show great promise in the treatment of neuroinflammation and malignant diseases.

The role of sphingolipid rheostat in the adult-type diffuse glioma pathogenesis

Gliomas are highly aggressive primary brain tumors, with glioblastoma multiforme being the most severe and the most common one. Aberrations in sphingolipid metabolism are a hallmark of glioma cells. The sphingolipid rheostat represents the balance between the pro-apoptotic ceramide and pro-survival sphingosine-1-phosphate (S1P), and in gliomas it is shifted toward cell survival and proliferation, promoting gliomas' aggressiveness, cellular migration, metastasis, and invasiveness. The sphingolipid rheostat can be altered by targeting enzymes that directly or indirectly affect the ratio of ceramide to S1P, leading to increased ceramide or decreased S1P levels. Targeting the sphingolipid rheostat offers a potential therapeutic pathway for glioma treatment which can be considered through reducing S1P levels or modulating S1P receptors to reduce cell proliferation, as well as through increasing ceramide levels to induce apoptosis in glioma cells. Although the practical translation into clinical therapy is still missing, sphingolipid rheostat targeting in gliomas has been of great research interest in recent years with several interesting achievements in the glioma therapy approach, offering hope for patients suffering from these vicious malignancies.

A stimulus responsive microneedle-based drug delivery system for cancer therapy

The intricate nature of the tumor microenvironment (TME) results in the inefficient delivery of anticancer drugs within tumor tissues, significantly compromising the therapeutic effect of cancer treatment. To address this issue, transdermal drug delivery microneedles (MNs) with high mechanical strength have emerged. Such MNs penetrate the skin barrier, enabling efficient drug delivery to tumor tissues. This approach enhances drug bioavailability, while also mitigating concerns such as liver and kidney toxicity associated with intravenous and oral drug administration. Notably, stimulus responsive MNs designed for drug delivery have the capacity to respond to various biological signals and pathological changes. This adaptability enables them to exert therapeutic effects within the TME, exploiting biochemical variations and tailoring treatment strategies to suit tumor characteristics. The present review surveys recent advancements in responsive MN systems. This comprehensive analysis serves as a valuable reference for the prospective application of smart MN drug delivery systems in cancer therapy.

The serine palmitoyltransferase core subunit StLcb2 regulates sphingolipid metabolism and promotes Setosphaeria turcica pathogenicity by modulating appressorium development

The fungal pathogen Setosphaeria turcica (S. turcica) causes northern corn leaf blight (NCLB), resulting in significant yield and economic losses in maize. To elucidate the metabolic pathways essential for its pathogenicity, we investigated the metabolome of S. turcica during appressorium development, a critical stage for host infection. Our analysis indicated a substantial enrichment of sphingosine and related compounds during this phase. The application of chemical inhibitors to disrupt sphingolipid metabolism confirmed their pivotal role in appressorium formation and pathogenicity. Additionally, silencing of the serine palmitoyl transferase (Spt) core subunit gene StLCB2 led to significant alterations in fungal morphology and growth, accompanied by changes in cell membrane integrity, surface hydrophobicity, melanin, and sphingosine synthesis. These findings underscore the importance of sphingolipids in the pathogenicity of S. turcica and suggest that targeting specific components of the sphingolipid pathway could aid in developing novel fungicides or genetically engineered maize varieties with increased resistance to NCLB.

Identifying genes associated with disease outcomes using joint sparse canonical correlation analysis-An application in renal clear cell carcinoma

Somatic changes like copy number aberrations (CNAs) and epigenetic alterations like methylation have pivotal effects on disease outcomes and prognosis in cancer, by regulating gene expressions, that drive critical biological processes. To identify potential biomarkers and molecular targets and understand how they impact disease outcomes, it is important to identify key groups of CNAs, the associated methylation, and the gene expressions they impact, through a joint integrative analysis. Here, we propose a novel analysis pipeline, the joint sparse canonical correlation analysis (jsCCA), an extension of sCCA, to effectively identify an ensemble of CNAs, methylation sites and gene (expression) components in the context of disease endpoints, especially tumor characteristics. Our approach detects potentially orthogonal gene components that are highly correlated with sets of methylation sites which in turn are correlated with sets of CNA sites. It then identifies the genes within these components that are associated with the outcome. Further, we aggregate the effect of each gene expression set on tumor stage by constructing "gene component scores" and test its interaction with traditional risk factors. Analyzing clinical and genomic data on 515 renal clear cell carcinoma (ccRCC) patients from the TCGA-KIRC, we found eight gene components to be associated with methylation sites, regulated by groups of proximally located CNA sites. Association analysis with tumor stage at diagnosis identified a novel association of expression of ASAH1 gene trans-regulated by methylation of several genes including SIX5 and by CNAs in the 10q25 region including TCF7L2. Further analysis to quantify the overall effect of gene sets on tumor stage, revealed that two of the eight gene components have significant interaction with smoking in relation to tumor stage. These gene components represent distinct biological functions including immune function, inflammatory responses, and hypoxia-regulated pathways. Our findings suggest that jsCCA analysis can identify interpretable and important genes, regulatory structures, and clinically consequential pathways. Such methods are warranted for comprehensive analysis of multimodal data especially in cancer genomics.

Integration of network pharmacology, metabolomics and lipidomics for clarifying the role of sphingolipid metabolism in the treatment of liver cancer by regorafenib

AIMS

Regorafenib, an FDA-approved drug for advanced primary liver cancer (PLC), could provide survival benefits for patients. However, markers for its therapeutic sensitivity are lacking. This study seeks to identify sensitive targets of regorafenib in PLC from the perspective of small molecular metabolites.

MATERIALS AND METHODS

Initiated with network pharmacology (NP) to map regorafenib's target landscape and metabolic regulatory network in liver cancer. Subsequently, regorafenib's impact on hepatoma cells was evaluated by flow cytometry, western blotting (WB) and cell viability assay. Advanced metabolomics and lipidomics were employed to elucidate regorafenib's metabolic reprogramming effects in liver cancer. Metabolic enzyme expression was assessed by WB, immunohistochemical and immunofluorescence assays. Ultimately, mendelian randomization (MR) analysis was utilized to investigate the potential causality of sphingolipid metabolism in hepatic cancer.

KEY FINDINGS

Regorafenib was observed to inhibit hepatoma cell proliferation and cell cycle progression at G0/G1 phase, resulting in significant alterations in sphingolipid levels. It promoted the significant accumulation of 16:0 dihydroceramide (16:0 dhCer) by upregulating ceramide synthase 6 (CERS6) expression and inhibiting dihydroceramide desaturase 1 (DEGS1) activity. The MR analysis revealed that DEGS1 was a risk factor for the development and progression of liver cancer, while cumulative 16:0 dhCer was a protective factor.

SIGNIFICANCE

Sphingolipids, particularly dhCer and regulatory enzymes, may be potential sensitive markers of regorafenib in the treatment of liver cancer, providing new insights for enhancing the treated efficacy of regorafenib in liver cancer.

Long non-coding RNAs-sphingolipid metabolism nexus: Potential targets for cancer treatment

Long non-coding RNAs (lncRNAs) have emerged as pivotal regulators of cancer pathogenesis, influencing various cellular processes and contributing to tumorigenesis. Sphingolipid metabolism has garnered interest as a potential target for cancer therapy owing to its considerable diagnostic and prognostic value. Recent studies have demonstrated that lncRNAs regulate tumor-associated metabolic reprogramming via sphingolipid metabolism. However, the precise nature of the interactions between lncRNAs and sphingolipid metabolism remains unclear. This review summarizes the key roles of lncRNAs and sphingolipid metabolism in tumorigenesis. We emphasize that the interaction between lncRNAs and sphingolipid metabolism influences their impact on both cancer prognosis and drug resistance. These findings suggest that lncRNA-sphingolipid metabolism interaction holds great potential as a newl target for cancer treatment.

Sphingolipid metabolism and regulated cell death in malignant melanoma

Malignant melanoma (MM) is a highly invasive and therapeutically resistant skin malignancy, posing a significant clinical challenge in its treatment. Programmed cell death plays a crucial role in the occurrence and progression of MM. Sphingolipids (SP), as a class of bioactive lipids, may be associated with many kinds of diseases. SPs regulate various forms of programmed cell death in tumors, including apoptosis, necroptosis, ferroptosis, and more. This review will delve into the mechanisms by which different types of SPs modulate various forms of programmed cell death in MM, such as their regulation of cell membrane permeability and signaling pathways, and how they influence the survival and death fate of MM cells. An in-depth exploration of the role of SPs in programmed cell death in MM aids in unraveling the molecular mechanisms of melanoma development and holds significant importance in developing novel therapeutic strategies.

Evaluation of glucocorticoid-related genes reveals GPD1 as a therapeutic target and regulator of sphingosine 1-phosphate metabolism in CRPC

Prostate cancer (PCa) is an androgen-dependent disease, with castration-resistant prostate cancer (CRPC) being an advanced stage that no longer responds to androgen deprivation therapy (ADT). Mounting evidence suggests that glucocorticoid receptors (GR) confer resistance to ADT in CRPC patients by bypassing androgen receptor (AR) blockade. GR, as a novel therapeutic target in CRPC, has attracted substantial attention worldwide. This study utilized bioinformatic analysis of publicly available CRPC single-cell data to develop a consensus glucocorticoid-related signature (Glu-sig) that can serve as an independent predictor for relapse-free survival. Our results revealed that the signature demonstrated consistent and robust performance across seven publicly accessible datasets and an internal cohort. Furthermore, our findings demonstrated that glycerol-3-phosphate dehydrogenase 1 (GPD1) in Glu-sig can significantly promote CRPC progression by mediating the cell cycle pathway. Additionally, GPD1 was shown to be regulated by GR, with the GR antagonist mifepristone enhancing the anti-tumorigenic effects of GPD1 in CRPC cells. Mechanistically, targeting GPD1 induced the production of sphingosine 1-phosphate (S1P) and enhanced histone acetylation, thereby inducing the transcription of p21 that involved in cell cycle regulation. In conclusion, Glu-sig could serve as a robust and promising tool to improve the clinical outcomes of PCa patients, and modulating the GR/GPD1 axis that promotes tumor growth may be a promising approach for delaying CRPC progression.

Comprehensive profiling of serum glycosphingolipids to discover the diagnostic biomarkers of lung cancer and uncover the variation of glycosphingolipid networks in different lung cancer subtypes

Glycosphingolipids are glycolipid complexes formed by an oligosaccharide chain covalently linked to a ceramide backbone and play important roles in the occurrence and metastasis of lung cancer. In this study, an UHPLC-HRMS method was developed for the comprehensive profiling of glycosphingolipids, with an in-house library constructed for data interpretation. Serum glycosphingolipids were profiled in 31 healthy controls (HCs) and 92 lung cancer patients with different pathologic subtypes. Over 1700 glycosphingolipids were detected in human serum based on the novel method. A total of 567 differential glycosphingolipids (adjusted P < 0.05, and fold change > 2) were found between lung cancer patients and HCs. Glycosphingolipids can be used as potential biomarkers for lung cancer diagnosis, with sensitivity much higher than that of traditional serum tumor markers. The levels of most glycosphingolipids in squamous cell carcinoma (Squa) were significantly lower than those in small cell lung cancer (SCLC) and adenocarcinoma (Aden). The highest Cer1P abundance in SCLC patients among the three different subtypes of lung cancer was thought to be related to the high malignancy and metastasis of SCLC. An artificial neural network (ANN) model was constructed for the discrimination of the three different subtypes of lung cancer, with accuracy higher than 93%. Beyond providing biomarkers and statistical models for the diagnosis of lung cancer and discrimination of lung cancer subtypes, this study uncovered the variation of glycosphingolipid networks in different subtypes of lung cancer and thereby provided a novel insight to study the pathogenesis of lung cancer and explore therapeutic targets.

Glycosylation of ceramide synthase 6 is required for its activity

Sphingolipids play key roles in membrane structure and cellular signaling. Ceramide synthase (CerS)-generated ceramide is implicated in cellular stress responses and induction of apoptosis. Ceramide and other sphingolipids are linked to the induction of ER stress response pathways. However, the mechanisms by which ceramide modulates ER stress signaling are not well understood. Here, we show that the ER stress inducer brefeldin A (BFA) causes increased glycosylation of CerS6, and that treatment with BFA causes increased endogenous ceramide accumulation. To our surprise, we found that CerS6 activity was not affected by BFA-induced glycosylation. Instead, our data show that basal glycosylation of CerS6 at Asn18 is required for CerS6 activity. We used a robust HCT116 CRISPR-Cas9 CerS6 KO with reintroduction of either WT CerS6 or a mutant CerS6 with a point mutation at asparagine-18 to an alanine (N18A) which abrogated glycosylation at that residue. Our data show that cells stably expressing the N18A mutant CerS6 had significantly lower activity in vitro and in situ as compared to WT CerS6 expressing cells. Further, the defective CerS6 with N18A mutation also had defects in GSK3β, AKT, JNK, and STAT3 signaling. Despite being required for CerS6 activity, Asn18 glycosylation did not influence ER stress response pathways. Overall, our study provides vital insight into the regulation of CerS6 activity by posttranslational modification at Asn18 and identifies glycosylation of CerS6 to be important for ceramide generation and regulation of downstream cellular signaling pathways.

Bio-Inspired Polymeric Solid Lipid Nanoparticles for siRNA Delivery: Cytotoxicity and Cellular Uptake In Vitro

Nanomedicine has introduced strategies that provide precise diagnosis and treatment with fewer side effects than traditional therapies. Treatments for neurodegenerative disorders, including Parkinson's disease, are palliative, necessitating an innovative delivery system with a curative function. This study investigated a solid lipid nanoparticle (SLNP) system's ability to bind and safely deliver siRNA in vitro. SLNPS were formulated using sphingomyelin and cholesterol, with Ginkgo biloba leaf extract (GBE) incorporated to enhance biocompatibility and neuroprotection. Poly-L-lysine (PLL) functionalization ensured successful siRNA binding, safe transport, and protection from nuclease degradation. SLNPs were physicochemically characterized, with binding and protection of siRNA assessed using agarose gels. Cytotoxicity, apoptotic induction, and cellular uptake studies were undertaken in the human neuroblastoma (SH-SY5Y) and embryonic kidney (HEK293) cells. The GBE-PLL-SLNPs had an average size of 93.2 nm and demonstrated enhanced binding and protection of the siRNA from enzyme digestion, with minimal cytotoxicity in HEK293 (<10%) and SH-SY5Y cells (<15%). Caspase 3/7 activity was significantly reduced in both cells, while efficient cellular uptake was noted. The present study provided a solid basis as a proof of principle study for future applications of the potential therapeutic in vitro, promising to address the unmet medical needs of patients with neurological disorders.

UGT8 mediated sulfatide synthesis modulates BAX localization and dictates apoptosis sensitivity of colorectal cancer

Elevated de novo lipid synthesis is a remarkable adaptation of cancer cells that can be exploited for therapy. However, the role of altered lipid metabolism in the regulation of apoptosis is still poorly understood. Using thermal proteome profiling, we identified Manidipine-2HCl, targeting UGT8, a key enzyme in the synthesis of sulfatides. In agreement, lipidomic analysis indicated that sulfatides are strongly reduced in colorectal cancer cells upon treatment with Manidipine-2HCl. Intriguingly, this reduction led to severe mitochondrial swelling and a strong synergism with BH3 mimetics targeting BCL-XL, leading to the activation of mitochondria-dependent apoptosis. Mechanistically, Manidipine-2HCl enhanced mitochondrial BAX localization in a sulfatide-dependent fashion, facilitating its activation by BH3 mimetics. In conclusion, our data indicates that UGT8 mediated synthesis of sulfatides controls mitochondrial homeostasis and BAX localization, dictating apoptosis sensitivity of colorectal cancer cells.

The role of ACER2 in intestinal sphingolipid metabolism and gastrointestinal cancers

Sphingolipids, particularly sphingosine-1-phosphate (S1P), are bioactive lipids involved in regulating cellular processes such as proliferation, apoptosis, inflammation, and tumor progression. Alkaline ceramidase 2 (ACER2) plays a critical role in sphingolipid metabolism by catalyzing the hydrolysis of ceramide to sphingosine, which is subsequently converted to S1P. Dysregulation of ACER2 has been implicated in various gastrointestinal cancers, including colorectal cancer, gastric cancer, and hepatocellular carcinoma. ACER2-mediated sphingolipid signaling, particularly through the SphK/S1P pathway, influences cancer development by modulating immune responses, inflammation, and the balance between cell survival and death. This review examines the physiological functions of ACER2, and its role in sphingolipid metabolism, and its contribution to the pathogenesis of gastrointestinal cancers. Understanding the mechanisms by which ACER2 regulates tumor progression and immune modulation may open new avenues for targeted therapies in gastrointestinal malignancies.

Sparstolonin B Reduces Estrogen-Dependent Proliferation in Cancer Cells: Possible Role of Ceramide and PI3K/AKT/mTOR Inhibition

Background: The aim of this study was to determine the effect of Sparstolonin B (SsnB) on cell proliferation and apoptosis in human breast cancer (MCF-7) and human ovarian epithelial cancer (OVCAR-3) cell lines in the presence and absence of estradiol hemihydrate (ES). Phosphoinositol-3 kinase (PI3K), phosphorylated protein kinase B alpha (p-AKT), phosphorylated mTOR (mechanistic target of rapamycin) signaling proteins, and sphingomyelin/ceramide metabolites were also measured within the scope of the study. Methods: The anti-proliferative effects of SsnB therapy were evaluated over a range of times and concentrations. Cell proliferation was determined by measuring the Proliferating Cell Nuclear Antigen (PCNA). PCNA was quantified by ELISA and cell distribution was assessed by immunofluorescence microscopy. MTT analysis was used to test the vitality of the cells, while LC-MS/MS was used to analyze the amounts of ceramides (CERs), sphingosine-1-phosphate (S1P), and sphingomyelins (SMs). TUNEL labeling was used to assess apoptosis, while immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA) were used to measure the levels of PI3K, p-AKT, and p-mTOR proteins. Results: Sparstolonin B administration significantly decreased cell viability in MCF-7 and OVCAR-3 cells both in the presence and absence of ES, while it did not cause toxicity in healthy human fibroblasts. In comparison to controls, cancer cells treated with SsnB showed a significant drop in the levels of S1P, PI3K, p-AKT, and p-mTOR. In cancer cells cultured with SsnB, a significant increase in intracellular concentrations of C16-C24 CERs and apoptosis was observed. Conclusions: SsnB downregulated the levels of S1P, PI3K, p-AKT, and p-mTOR while reducing cell proliferation and promoting ceramide buildup and apoptosis.

Label-Free Prediction of Tumor Metastatic Potential via Ramanome

Assessing metastatic potential is crucial for cancer treatment strategies. However, current methods are time-consuming, labor-intensive, and have limited sample accessibility. Therefore, this study aims to investigate the urgent need for rapid and accurate approaches by proposing a Ramanome-based metastasis index (RMI) using machine learning of single-cell Raman spectra to rapidly and accurately assess tumor cell metastatic potential. Validation with various cultured tumor cells and a mouse orthotopic model of pancreatic ductal adenocarcinoma show a Kendall rank correlation coefficient of 1 compared to Transwell experiments and histopathological assessments. Significantly, lipid-related Raman peaks are most influential in determining RMI. The lipidomic analysis confirmed strong correlations between metastatic potential and phosphatidylcholine, phosphatidylethanolamine, cholesteryl ester, ceramide, and bis(monoacylglycero)phosphate, crucial in cell membrane composition or signal transduction. Therefore, RMI is a valuable tool for predicting tumor metastatic potential and providing insights into metastasis mechanisms.

A First-in-Human Phase I Study of BXQ-350, a First-in-Class Sphingolipid Metabolism Regulator, in Patients with Advanced/Recurrent Solid Tumors or High-Grade Gliomas

PURPOSE

BXQ-350, a nanovesicle formulation of saposin C, is an allosteric sphingolipid metabolism regulator that increases proapoptotic ceramide and decreases oncogenic sphingosine-1-phosphate levels. We conducted a first-in-human phase I study of BXQ-350.

PATIENTS AND METHODS

Adults (≥18 years old) with advanced/recurrent, treatment-refractory solid tumors or high-grade gliomas received BXQ-350 intravenously in five dose cohorts (0.7-2.4 mg/kg) in a 3+3 dose escalation and expansion design. The primary endpoints during dose escalation were dose-limiting toxicities and maximum tolerated dose; the primary objective in expansion parts was assessment of antitumor activity (RECIST v1.1/Response Assessment in Neuro-Oncology criteria).

RESULTS

Eighty-six patients were enrolled. Dose-limiting toxicities were not observed during dose escalation (n = 18), and a maximum tolerated dose was not identified. An additional 68 patients received the 2.4 mg/kg dose. Nine patients (10%) discontinued due to adverse events. The most common treatment-related adverse events were nausea (24%) and fatigue (23%). Eight patients had a progression-free survival of ≥6 months. Two of these achieved a partial response, and six had stable disease, among whom three had a reduction in ≥1 target lesion. Of those with progression-free survival of ≥6 months, seven remained on study for >12 months, five for >24 months, and after 7 years, two remained on study without disease progression.

CONCLUSIONS

BXQ-350 was well-tolerated as monotherapy at doses up to 2.4 mg/kg. It provided some lasting clinical benefit in patients with recurrent solid malignancies across several tumor types, consistent with a decreased systemic sphingosine-1-phosphate/ceramide metabolic rheostat. BXQ-350 warrants further clinical investigation alone and combined with standard of care for advanced solid tumors.

Highly sensitive microfluidic sensor using integrated optical fiber and real-time single-cell Raman spectroscopy for diagnosis of pancreatic cancer

Pancreatic cancer is notoriously lethal due to its late diagnosis and poor patient response to treatments, posing a significant clinical challenge. This study introduced a novel approach that combines a single-cell capturing platform, tumor-targeted silver (Ag) nanoprobes, and precisely docking tapered fiber integrated with Raman spectroscopy. This approach focuses on early detection and progression monitoring of pancreatic cancer. Utilizing tumor-targeted Ag nanoparticles and tapered multimode fibers enhances Raman signals, minimizes light loss, and reduces background noise. This advanced Raman system allows for detailed molecular spectroscopic examination of individual cells, offering more practical information and enabling earlier detection and accurate staging of pancreatic cancer compared to conventional multicellular Raman spectroscopy. Transcriptomic analysis using high-throughput gene screening and transcriptomic databases confirmed the ability and accuracy of this method to identify molecular changes in normal, early, and metastatic pancreatic cancer cells. Key findings revealed that cell adhesion, migration, and the extracellular matrix are closely related to single-cell Raman spectroscopy (SCRS) results, highlighting components such as collagen, phospholipids, and carotene. Therefore, the SCRS approach provides a comprehensive view of the molecular composition, biological function, and material changes in cells, offering a novel, accurate, reliable, rapid, and efficient method for diagnosing and monitoring pancreatic cancer.

Tumor suppressor ACER1 correlates with prognosis and Immune Infiltration in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is notorious for poor prognoses, and effective biomarkers are urgently needed for early diagnosis of HNSCC patients. We investigate the role of alkaline ceramidase 1 (ACER1) and its relationship with immune infiltration in HNSCC. The differential expression and clinical prognostic significance of ACER1 in HNSCC patients are explored using bioinformatics methods and verified in human HNSCC samples. Genetic mutation, DNA methylation and drug sensitivity linked with ACER1 are examined. The potential biological function of ACER1 co-expression genes is assessed, and a series of functional assays are performed on ACER1in vitro. The results comprehensively reveal a relationship between ACER1 and immune infiltration in HNSCC patients. ACER1 expression is significantly downregulated in HNSCC tissues and closely correlated with better prognoses for HNSCC patients, and this prognostic significance is determined by distinct clinical characteristics. Genetic alteration and promoter hypomethylation of ACER1 are involved in progression of HNSCC, and ACER1 expression is significantly related to several drug sensitivities. Functional analysis shows that ACER1 co-expression genes are mainly enriched in the sphingolipid signaling pathway associated with inhibition of tumorigenesis, leading to better prognoses for HNSCC patients. In vitro, ACER1 overexpression inhibits proliferation and migration, induces apoptosis, and promotes adhesion of Fadu and SCC9 cells. In addition, high ACER1 expression is closely linked with infiltration levels of immune cells, and strongly associated with biomarkers of immune cells in HNSCC, suggesting the important role of ACER1 in regulating tumor immunity in HNSCC patients. In summary, ACER1 may be a useful indicator for diagnosis and prognosis, and may regulate immune infiltration in HNSCC patients, thus promising targeted immunotherapy for HNSCC.

Urothelial Urinary Bladder Cancer Is Characterized by Stage-Dependent Aberrations in Metabolism of Bioactive Sphingolipids

Although dysregulated sphingolipid metabolism was observed in many malignant tumors, bladder cancer has not yet been examined in this regard. This study aims to investigate the metabolism of bioactive sphingolipids across different stages of urothelial urinary bladder cancer (UBC). Forty-eight patients with UBC were included in this study. The neoplasms were classified as either non-muscle-invasive (NMIBC, n = 24) or muscle-invasive (MIBC, n = 24). Samples of the healthy bladder tissue were taken from the patients who underwent radical cystectomy. The content of sphingolipids was measured using an HPLC method, and the mRNA expression of sphingolipid transporters and metabolizing enzymes was evaluated using RT-PCR. Compared to the healthy bladder tissue, the UBC, regardless of the stage, showed an elevated expression of SphK1, Spns2, and ABCC1. The changes in the level of bioactive sphingolipids were strongly stage-dependent. MIBC showed accumulation of sphingosine-1-phosphate (S1P) and ceramide, whereas the content of these sphingolipids in the NMIBC tumor was not different from that of healthy tissue. Moreover, MIBC, compared to NMIBC, was characterized by higher levels of sphingosine and dihydroceramide. We conclude that profound alterations in sphingolipid metabolism develop upon UBC transition from non-muscle-invasive to muscle-invasive. They include the accumulation of S1P, resulting from the increased availability of sphingosine generated from ceramide, which also builds up due to a further activation of its de novo synthesis. We hypothesize that the dysregulation of S1P metabolism leading to the accumulation of this tumor-promoting sphingolipid contributes to the progression of UBC.

Integrated bulk and single-cell profiling characterize sphingolipid metabolism in pancreatic cancer

BACKGROUND

Abnormal sphingolipid metabolism (SM) is closely linked to the incidence of cancers. However, the role of SM in pancreatic cancer (PC) remains unclear. This study aims to explore the significance of SM in the prognosis, immune microenvironment, and treatment of PC.

METHODS

Single-cell and bulk transcriptome data of PC were acquired via TCGA and GEO databases. SM-related genes (SMRGs) were obtained via MSigDB database. Consensus clustering was utilized to construct SM-related molecular subtypes. LASSO and Cox regression were utilized to build SM-related prognostic signature. ESTIMATE and CIBERSORT algorithms were employed to assess the tumour immune microenvironment. OncoPredict package was used to predict drug sensitivity. CCK-8, scratch, and transwell experiments were performed to analyze the function of ANKRD22 in PC cell line PANC-1 and BxPC-3.

RESULTS

A total of 153 SMRGs were acquired, of which 48 were linked to PC patients' prognosis. Two SM-related subtypes (SMRGcluster A and B) were identified in PC. SMRGcluster A had a poorer outcome and more active SM process compared to SMRGcluster B. Immune analysis revealed that SMRGcluster B had higher immune and stromal scores and CD8 + T cell abundance, while SMRGcluster A had a higher tumour purity score and M0 macrophages and activated dendritic cell abundance. PC with SMRGcluster B was more susceptible to gemcitabine, paclitaxel, and oxaliplatin. Then SM-related prognostic model (including ANLN, ANKRD22, and DKK1) was built, which had a very good predictive performance. Single-cell analysis revealed that in PC microenvironment, macrophages, epithelial cells, and endothelial cells had relatively higher SM activity. ANKRD22, DKK1, and ANLN have relatively higher expression levels in epithelial cells. Cell subpopulations with high expression of ANKRD22, DKK1, and ANLN had more active SM activity. In vitro experiments showed that ANKRD22 knockdown can inhibit the proliferation, migration, and invasion of PC cells.

CONCLUSION

This study revealed the important significance of SM in PC and identified SM-associated molecular subtypes and prognostic model, which provided novel perspectives on the stratification, prognostic prediction, and precision treatment of PC patients.

Protective Role of Sphingosine-1-Phosphate During Radiation-Induced Testicular Injury

The impact of ionizing radiation on the male reproductive system is gaining increasing attention, particularly when it comes to testicular damage, which may result in decreased sperm quality and hormonal imbalances. Finding effective protective measures to mitigate testicular damage caused by radiation has become a focal point in the biomedical field. S1P, an essential biological signaling molecule, has garnered significant interest due to its multiple roles in regulating cellular functions and its protective effects against radiation-induced testicular injury. S1P not only effectively reduces the generation of ROS induced by radiation but also alleviates oxidative stress by enhancing the activity of antioxidant enzymes. Furthermore, S1P inhibits radiation-induced cell apoptosis by regulating the expression of anti-apoptotic and pro-apoptotic proteins. Additionally, S1P alleviates radiation-induced inflammation by inhibiting the production of inflammatory factors, thereby further protecting testicular tissue. In summary, S1P effectively reduces radiation-induced testicular damage through multiple mechanisms, offering a promising therapeutic approach to safeguard male reproductive health. Future research should explore the specific mechanisms of action and clinical application potential of S1P, aiming to contribute significantly to the prevention and treatment of radiation damage.

Targeting sphingosine 1-phosphate and sphingosine kinases in pancreatic cancer: mechanisms and therapeutic potential

Pancreatic cancer is known to be the most lethal cancer. Fewer new treatments are being developed for pancreatic cancer as compared to other cancers. The bioactive lipid S1P, which is mainly regulated by sphingosine kinase 1 (SK1) and sphingosine kinase 2 (SK2) enzymes, plays significant roles in pancreatic cancer initiation and exacerbation. S1P controls many signaling pathways to modulate the progression of pancreatic cancer through the G-coupled receptor S1PR1-5. Several papers reporting amelioration of pancreatic cancer via modulation of S1P levels or downstream signaling pathways have previously been published. In this paper, for the first time, we have reviewed the results of previous studies to understand how S1P and its receptors contribute to the development of pancreatic cancer, and whether S1P can be a therapeutic target. In addition, we have also reviewed papers dealing with the effects of SK1 and SK2, which are kinases that regulate the level of S1P, on the pathogenesis of pancreatic cancer. We have also listed available drugs that particularly focus on S1P, S1PRs, SK1, and SK2 for the treatment of pancreatic cancer. Through this review, we would like to suggest that the SK/S1P/S1PR signaling system can be an important target for treating pancreatic cancer, where a new treatment target is desperately warranted.

Esophageal cancer risk is influenced by genetically determined blood metabolites

It remains unclear what causes esophageal cancer (EC), but blood metabolites have been connected to it. Our study performed a Mendelian randomization (MR) analysis to assess the causality from genetically proxied 1400 blood metabolites to EC level. A two-sample MR analysis was employed to evaluate the causal relationship between 1400 blood metabolites and EC. Initially, the EC genome-wide association study (GWAS) data (from Jiang L et al) were examined, leading to the identification of certain metabolites. Subsequently, another set of EC GWAS data from FINNGEN was utilized to validate the findings. Causality was primarily determined through inverse variance weighting, with additional support from the MR-Egger, weighted median, and MR-PRESSO models. Heterogeneity was assessed using the MR Cochran Q test. The MR-Egger intercept and MR-PRESSO global methods were employed to detect multicollinearity. In this study, Bonferroni corrected P value was used for significance threshold. We found 2 metabolites with overlaps, which are lipids. Docosatrienoate (22:3n3) was found to be causally associated with a decreased risk of EC, as evidenced by the EC GWAS data (from Jiang et al) (odds ratio [OR] = 0.620, 95% confidence interval [CI] = 0.390-0.986, P = .044) and the EC GWAS data (from FINNGEN) (OR = 0.77, 95% CI = 0.6-0.99, P = .042), these results were consistent across both data sets. Another overlapping metabolite, glycosyl-N-(2-hydroxyneuramoyl)-sphingosine, was associated with the risk of ES, with EC GWAS data (from Jiang L et al) (OR = 1.536, 95% CI = 1.000-2.360, P = .049), while EC GWAS data (from FINNGEN) (OR = 0.733, 95% CI = 0.574-0.937, P = .013), the 2 data had opposite conclusions. The findings of this study indicate a potential association between lipid metabolites (Docosatrienoate (22:3n3) and glycosyl-N-(2-hydroxynervonoyl)-sphingosine (d18:1/24:1 (2OH))) and the risk of esophageal carcinogenesis.

Metabolic biomarkers of neonatal sepsis: identification using metabolomics combined with machine learning

Background

Sepsis is a common disease associated with neonatal and infant mortality, and for diagnosis, blood culture is currently the gold standard method, but it has a low positivity rate and requires more than 2 days to develop. Meanwhile, unfortunately, the specific biomarkers for the early and timely diagnosis of sepsis in infants and for the determination of the severity of this disease are lacking in clinical practice.

Methods

Samples from 18 sepsis infants with comorbidities, 25 sepsis infants without comorbidities, and 25 infants with noninfectious diseases were evaluated using a serum metabolomics approach based on liquid chromatography‒mass spectrometry (LC‒MS) technology. Differentially abundant metabolites were screened via multivariate statistical analysis. In addition, least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) analyses were conducted to identify the key metabolites in infants with sepsis and without infections. The random forest algorithm was applied to determine key differentially abundant metabolites between sepsis infants with and without comorbidities. Receiver operating characteristic (ROC) curves were generated for biomarker value testing. Finally, a metabolic pathway analysis was conducted to explore the metabolic and signaling pathways associated with the identified differentially abundant metabolites.

Results

A total of 189 metabolites exhibited significant differences between infectious infants and noninfectious infants, while 137 distinct metabolites exhibited differences between septic infants with and without comorbidities. After screening for the key differentially abundant metabolites using LASSO and SVM-RFE analyses, hexylamine, psychosine sulfate, LysoPC (18:1 (9Z)/0:0), 2,4,6-tribromophenol, and 25-cinnamoyl-vulgaroside were retained for the diagnosis of infant sepsis. ROC curve analysis revealed that the area under the curve (AUC) was 0.9200 for hexylamine, 0.9749 for psychosine sulfate, 0.9684 for LysoPC (18:1 (9Z)/0:0), 0.7405 for 2,4,6-tribromophenol, 0.8893 for 25-cinnamoyl-vulgaroside, and 1.000 for the combination of all metabolites. When the septic infants with comorbidities were compared to those without comorbidities, four endogenous metabolites with the greatest importance were identified using the random forest algorithm, namely, 12-oxo-20-trihydroxy-leukotriene B4, dihydrovaltrate, PA (8:0/12:0), and 2-heptanethiol. The ROC curve analysis of these four key differentially abundant metabolites revealed that the AUC was 1 for all four metabolites. Pathway analysis indicated that phenylalanine, tyrosine, and tryptophan biosynthesis, phenylalanine metabolism, and porphyrin metabolism play important roles in infant sepsis.

Conclusion

Serum metabolite profiles were identified, and machine learning was applied to identify the key differentially abundant metabolites in septic infants with comorbidities, septic infants without comorbidities, and infants without infectious diseases. The findings obtained are expected to facilitate the early diagnosis of sepsis in infants and determine the severity of the disease.

Machine learning models to identify lead compound and substitution optimization to have derived energetics and conformational stability through docking and MD simulations for sphingosine kinase 1

Sphingosine kinases (SphKs) are a group of important enzymes that circulate at low micromolar concentrations in mammals and have received considerable attention due to the roles they play in a broad array of biological processes including apoptosis, mutagenesis, lymphocyte migration, radio- and chemo-sensitization, and angiogenesis. In the present study, we constructed three classification models by four machine learning (ML) algorithms including naive bayes (NB), support vector machine (SVM), logistic regression, and random forest from 395 compounds. The generated ML models were validated by fivefold cross validation. Five different scaffold hit fragments resulted from SVM model-based virtual screening and docking results indicate that all the five fragments exhibit common hydrogen bond interaction a catalytic residue of SphK1. Further, molecular dynamics (MD) simulations and binding free energy calculation had been carried out with the identified five fragment leads and three cocrystal inhibitors. The best 15 fragments were selected. Molecular dynamics (MD) simulations showed that among these compounds, 7 compounds have favorable binding energy compared with cocrystal inhibitors. Hence, the study showed that the present lead fragments could act as potential inhibitors against therapeutic target of cancers and neurodegenerative disorders.

A sphingolipid rheostat controls apoptosis versus apical cell extrusion as alternative tumour-suppressive mechanisms

Evasion of cell death is a hallmark of cancer, and consequently the induction of cell death is a common strategy in cancer treatment. However, the molecular mechanisms regulating different types of cell death are poorly understood. We have formerly shown that in the epidermis of hypomorphic zebrafish hai1a mutant embryos, pre-neoplastic transformations of keratinocytes caused by unrestrained activity of the type II transmembrane serine protease Matriptase-1 heal spontaneously. This healing is driven by Matriptase-dependent increased sphingosine kinase (SphK) activity and sphingosine-1-phosphate (S1P)-mediated keratinocyte loss via apical cell extrusion. In contrast, amorphic hai1afr26 mutants with even higher Matriptase-1 and SphK activity die within a few days. Here we show that this lethality is not due to epidermal carcinogenesis, but to aberrant tp53-independent apoptosis of keratinocytes caused by increased levels of pro-apoptotic C16 ceramides, sphingolipid counterparts to S1P within the sphingolipid rheostat, which severely compromises the epidermal barrier. Mathematical modelling of sphingolipid rheostat homeostasis, combined with in vivo manipulations of components of the rheostat or the ceramide de novo synthesis pathway, indicate that this unexpected overproduction of ceramides is caused by a negative feedback loop sensing ceramide levels and controlling ceramide replenishment via de novo synthesis. Therefore, despite their initial decrease due to increased conversion to S1P, ceramides eventually reach cell death-inducing levels, making transformed pre-neoplastic keratinocytes die even before they are extruded, thereby abrogating the normally barrier-preserving mode of apical live cell extrusion. Our results offer an in vivo perspective of the dynamics of sphingolipid homeostasis and its relevance for epithelial cell survival versus cell death, linking apical cell extrusion and apoptosis. Implications for human carcinomas and their treatments are discussed.

Detection and Validation of Organic Metabolites in Urine for Clear Cell Renal Cell Carcinoma Diagnosis

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) comprises the majority, approximately 70-80%, of renal cancer cases and often remains asymptomatic until incidentally detected during unrelated abdominal imaging or at advanced stages. Currently, standardized screening tests for renal cancer are lacking, which presents challenges in disease management and improving patient outcomes. This study aimed to identify ccRCC-specific volatile organic compounds (VOCs) in the urine of ccRCC-positive patients and develop a urinary VOC-based diagnostic model.

METHODS

This study involved 233 pretreatment ccRCC patients and 43 healthy individuals. VOC analysis utilized stir-bar sorptive extraction coupled with thermal desorption gas chromatography/mass spectrometry (SBSE-TD-GC/MS). A ccRCC diagnostic model was established via logistic regression, trained on 163 ccRCC cases versus 31 controls, and validated with 70 ccRCC cases versus 12 controls, resulting in a ccRCC diagnostic model involving 24 VOC markers.

RESULTS

The findings demonstrated promising diagnostic efficacy, with an Area Under the Curve (AUC) of 0.94, 86% sensitivity, and 92% specificity.

CONCLUSIONS

This study highlights the feasibility of using urine as a reliable biospecimen for identifying VOC biomarkers in ccRCC. While further validation in larger cohorts is necessary, this study's capability to differentiate between ccRCC and control groups, despite sample size limitations, holds significant promise.

Multi-omics analysis unveils the predictive value of IGF2BP3/SPHK1 signaling in cancer stem cells for prognosis and immunotherapeutic response in muscle-invasive bladder cancer

BACKGROUND

Muscle invasive bladder cancer (MIBC) is a life-threatening malignant tumor characterized by high metastasis rates, poor prognosis, and limited treatment options. Immune checkpoint inhibitors (ICIs) targeting PD-1 and PD-L1 represent an emerging treatment for MIBC immunotherapy. However, the characteristics of patients likely to benefit from immunotherapy remain unclear.

METHODS

We performed single-cell mass cytometry (CyTOF) analysis of 179,483 single cells to characterize potential immunotherapy-related cancer stem cells (CSCs)-like populations in the tumor microenvironment of 38 MIBC tissues. The upregulated expression of IGF2BP3 in CD274 + ALDH + CSC-like cells, which was associated with poor clinical prognosis, was analyzed by bulk RNA-sequencing data from an in-house cohort. The functional role of IGF2BP3 was determined through cell proliferation, colony formation, cell apoptosis and sphere formation assays. The regulation of SPHK1 expression by IGF2BP3 was  investigated using methylated RNA immunoprecipitation sequencing (MeRIP-seq) and bulk RNA-sequencing (bulk RNA-seq). We further utilized single-nucleus RNA sequencing (snRNA-seq) data from 67,988 cells of 25 MIBC tissues and single-cell RNA sequencing (scRNA-seq) data from MIBC patient-derived organoids to characterize the molecular features of bladder cancer cells co-expressing IGF2BP3 and SPHK1. Spatial transcriptomics (ST) and co-detection by indexing (CODEX) analysis were used to describe the spatial distribution and interactions of IGF2BP3 + SPHK1 + bladder cancer cells and immune cells.

RESULTS

A subset of CD274 + ALDH + CSC-like cells was identified, associating with immunosuppression and low survival rates in MIBC patients. IGF2BP3, an m6A reader gene, was found to be upregulated in the CD274 + ALDH + CSC-like cell population and linked to poor clinical prognosis in MIBC. Knockout of IGF2BP3 dramatically promoted cell apoptosis and reduced cell proliferation in T24 cells. By integrating MeRIP-seq and bulk RNA-seq analyses, we identified SPHK1 served as a substrate for IGF2BP3 in an m6A-dependent manner. Further snRNA-seq, scRNA-seq, ST, and CODEX analysis revealed a closer topographical distance between IGF2BP3 + SPHK1 + bladder cancer cells and exhausted CD8 + T cells, providing one explanation for the superior response to immunotherapy in IGF2BP3 + SPHK1 + bladder cancer cells-enriched patients. Finally, an ICI-associated signature was developed based on the enriched genes of IGF2BP3 + SPHK1 + bladder cancer cells, and its potential ability to predict the response to immunotherapy was validated in two independent immunotherapy cohort.

CONCLUSIONS

Our study highlighted the critical involvement of the IGF2BP3/SPHK1 signaling in maintaining the stemness of CSCs and promoting MIBC progression. Additionally, these findings suggested that the IGF2BP3/SPHK1 signaling might serve as a biomarker for prognosis and immunotherapy response in MIBC.

Alterations of Ceramides, Acylcarnitines, GlyceroLPLs, and Amines in NSCLC Tissues

Abnormal lipid metabolism plays an important role in cancer development. In this study, nontargeted lipidomic study on 230 tissue specimens from 79 nonsmall cell lung cancer (NSCLC) patients was conducted using ultraperformance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). Downregulation of sphingosine and medium-long-chain ceramides and short-medium-chain acylcarnitine, upregulation of long-chain acylcarnitine C20:0, and enhanced histamine methylation were revealed in NSCLC tissues. Compared with paired noncancerous tissues, adenocarcinoma (AC) tissues had significantly decreased levels of sphingosine, medium-long-chain ceramides (Cer d18:1/12:0 and Cer d16:1/14:0, Cer d18:0/16:0, Cer d18:1/16:0, Cer d18:2/16:0, Cer d18:2/18:0), short-medium-chain (C2-C16) acylcarnitines, LPC 20:0 and LPC 22:1, and significantly increased levels of the long-chain acylcarnitine C20:0, LPC 16:0, LPC P-16:0, LPC 20:1, LPC 20:2, glyceroPC, LPE 16:0, and LPE 18:2. In squamous cell carcinoma (SCC) tissues, sphingosine, Cer d18:2/16:0 and Cer d18:2/18:0, and short-medium-chain acylcarnitines had significantly lower levels, while long-chain acylcarnitines (C20:0, and C22:0 or C22:0 M), LPC 20:1, LPC 20:2, and N1,N12-diacetylspermine had significantly higher levels compared to controls. In AC and SCC tissues, the levels of LPG 18:0, LPG 18:1, and LPS 18:1 were significantly decreased, while the levels of ceramide-1-phosphate (C1P) d18:0/3:0 or LPE P-16:0, N1-acetylspermidine, and 1-methylhistamine were significantly increased than controls. Furthermore, an orthogonal partial least-squares-discriminant analysis (OPLS-DA) model based on a 4-lipid panel was established, showing good discrimination ability between cancerous and noncancerous tissues.

The sphingosine kinase 2 inhibitors ABC294640 and K145 elevate (dihydro)sphingosine 1-phosphate levels in various cells

Sphingosine kinases (SphKs), enzymes that produce the bioactive lipids dihydrosphingosine 1-phosphate (dhS1P) and sphingosine 1-phosphate (S1P), are associated with various diseases, including cancer and infections. For this reason, a number of SphK inhibitors have been developed. Although off-target effects have been described for selected agents, SphK inhibitors are mostly used in research without monitoring the effects on the sphingolipidome. We have now investigated the effects of seven commonly used SphK inhibitors (5c, ABC294640 (opaganib), N,N-dimethylsphingosine, K145, PF-543, SLM6031434, and SKI-II) on profiles of selected sphingolipids in Chang, HepG2, and human umbilical vein endothelial cells. While we observed the expected (dh)S1P reduction for N,N-dimethylsphingosine, PF-543, SKI-II, and SLM6031434, 5c showed hardly any effect. Remarkably, for K145 and ABC294640, both reported to be specific for SphK2, we observed dose-dependent strong increases in dhS1P and S1P across cell lines. Compensatory effects of SphK1 could be excluded, as this observation was also made in SphK1-deficient HK-2 cells. Furthermore, we observed effects on dihydroceramide desaturase activity for all inhibitors tested, as has been previously noted for ABC294640 and SKI-II. In additional mechanistic studies, we investigated the massive increase of dhS1P and S1P after short-term cell treatment with ABC294640 and K145 in more detail. We found that both compounds affect sphingolipid de novo synthesis, with 3-ketodihydrosphingosine reductase and dihydroceramide desaturase as their targets. Our study indicates that none of the seven SphK inhibitors tested was free of unexpected on-target and/or off-target effects. Therefore, it is important to monitor cellular sphingolipid profiles when SphK inhibitors are used in mechanistic studies.

Targeting SNAI1-Mediated Colorectal Cancer Chemoresistance and Stemness by Sphingosine Kinase 2 Inhibition

Background

Epithelial-to-mesenchymal transition (EMT), cancer stem cells (CSCs), and colorectal cancer (CRC) therapy resistance are closely associated. Prior reports have demonstrated that sphingosine-1-phosphate (S1P) supports stem cells and maintains the CSC phenotype. We hypothesized that the EMT inducer SNAI1 drives S1P signaling to amplify CSC self-renewal capacity and chemoresistance.

Methods

CRC cell lines with or without ectopic expression of SNAI1 were used to study the role of S1P signaling as mediators of cancer stemness and 5-fluorouracil (5FU) chemoresistance. The therapeutic ability of sphingosine kinase 2 (SPHK2) was assessed using siRNA and ABC294640, a SPHK2 inhibitor. CSCs were isolated from patient-derived xenografts (PDXs) and assessed for SPHK2 and SNAI1 expression.

Results

Ectopic SNAI1 expressing cell lines demonstrated elevated SPHK2 expression and increased SPHK2 promoter activity. SPHK2 inhibition with siRNA or ABC294640 ablated in vitro self-renewal and sensitized cells to 5FU. CSCs isolated from CRC PDXs express increased SPHK2 relative to the non-CSC population. Combination ABC294640/5FU therapy significantly inhibited tumor growth in mice and enhanced 5FU response in therapy-resistant CRC patient-derived tumor organoids (PDTOs).

Conclusions

SNAI1/SPHK2 signaling mediates cancer stemness and 5FU resistance, implicating S1P as a therapeutic target for CRC. The S1P inhibitor ABC294640 holds potential as a therapeutic agent to target CSCs in therapy refractory CRC.

Lipid droplet accumulation mediates macrophage survival and Treg recruitment via the CCL20/CCR6 axis in human hepatocellular carcinoma

Metabolic changes play a crucial role in determining the status and function of macrophages, but how lipid reprogramming in macrophages contributes to tumor progression is not yet fully understood. Here, we investigated the phenotype, contribution, and regulatory mechanisms of lipid droplet (LD)-laden macrophages (LLMs) in hepatocellular carcinoma (HCC). Enriched LLMs were found in tumor tissues and were associated with disease progression in HCC patients. The LLMs displayed immunosuppressive phenotypes (with extensive expression of TREM2, PD-L1, CD206, and CD163) and attenuated the antitumor activities of CD8+ T cells. Mechanistically, tumor-induced reshuffling of cellular lipids and TNFα-mediated uptake of tumoral fatty acids contribute to the generation of triglycerides and LDs in macrophages. LDs prolong LLM survival and promote CCL20 secretion, which further recruits CCR6+ Tregs to HCC tissue. Inhibiting LLM formation by targeting DGAT1 and DGAT2, which catalyze the synthesis of triglycerides, significantly reduced Treg recruitment, and delayed tumor growth in a mouse hepatic tumor model. Our results reveal the suppressive phenotypes and mechanisms of LLM enrichment in HCC and suggest the therapeutic potential of targeting LLMs for HCC patients.

Huperzine A targets Apolipoprotein E: A potential therapeutic drug for diabetic nephropathy based on omics analysis

AIMS

Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) without curative interventions currently. Huperzine A (Hup A), a natural alkaloid, has demonstrated significant hypoglycemic and anti-inflammatory effects. We aim to investigate the protective effects of Hup A on DN and explore the underlying mechanisms METHODS: We applied STZ induced diabetic rats as DN model and leveraged combination analysis of the transcriptome, metabolome, microbiome, and network pharmacology (NP). The total effect of Hup A on DN was detected (i.e. urine protein, renal tissue structure) and the differential genes were further verified at the level of diabetic patients, db/db mice and cells. Clinical data and small interfering RNA (siRNA)-Apoe were adopted.

RESULTS

Hup A alleviated kidney injury in DN rats. Transcriptomics data and Western blot indicated that the improvement in DN was primarily associated with Apoe and Apoc2. Additionally, metabolomics data demonstrated that DN-induced lipid metabolism disruption was regulated by Hup A, potentially involving sphingosine. Hup A also enriched microbial diversity and ameliorated DN-induced microbiota imbalance. Spearman's correlation analysis demonstrated significant associations among the transcriptome, metabolome, and microbiome. Apoe level was positively correlated with clinical biomarkers in DN patients. Si-Apoe also played protective role in podocytes. NP analysis also suggested that Hup A may treat DN by modulating lipid metabolism, microbial homeostasis, and apoptosis, further validating our findings.

CONCLUSIONS

Collectively, we provide the first evidence of the therapeutic effect of Hup A on DN, indicating that Hup A is a potential drug for the prevention and treatment of DN.