Cancer & Metabolism最新文献

Background: Leptomeningeal metastasis (LM) is a devastating complication of cancer that is difficult to treat. Thus, early diagnosis is essential for LM patients. However, cerebrospinal fluid (CSF) cytology has low sensitivity, and imaging approaches are ineffective. We explored targeted CSF metabolic profiling to discriminate among LM and other conditions affecting the central nervous system (CNS).

Methods: We quantitatively measured amino acids, biogenic amines, hexoses, acylcarnitines (AC), cholesteryl esters (CE), glycerides, phosphatidylcholines (PC), lysophosphatidylcholines (LPC), sphingomyelins (SM), and ceramides (Cer) in 117 CSF samples from various groups of healthy controls (HC, n = 10), patients with LM (LM, n = 47), parenchymal brain tumor (PBT, n = 45), and inflammatory disease (ID, n = 13) with internal standards using the Absolute IDQ- p400^® targeted mass spectrometry kit. Metabolites detected in > 90% of samples or showing a difference in proportional level between groups ≥ 75% were used in logistic regression models when there was no single metabolite with AUC = 1 for the groups of comparison.

Results: PC and SM had higher levels in LM than in PBT or HC, whereas LPC had lower level in PBT than the other groups. Glycerides and Cer levels were higher in PBT and LM than in HC. Long-chain AC level in PBT was lower than in LM or HC. A regression model including Ala, PC (42:7), PC (30:3), PC (37:0), and Tyr achieved complete discrimination (AUC = 1.0) between LM and HC. In comparison of PBT and HC, twenty-six individual metabolites allowed complete discrimination between two groups, and between ID and HC fourty-six individual lipid metabolites allowed complete discrimination. Twenty-one individual metabolites (18 ACs and 3 PCs) allowed complete discrimination between LM and PBT.

Conclusions: Using a commercial targeted liquid chromatography-mass spectrometry (LC-MS) metabolomics kit, we were able to differentiate LM from HC and PBT. Most of the discriminative metabolites among different diseases were lipid metabolites, for which their CNS distribution and quantification in different cell types are largely unknown, whereas amino acids, biogenic amines, and hexoses failed to show significant differences. Future validation studies with larger, controlled cohorts should be performed, and hopefully, the kit may expand its metabolite coverage for unique cancer cell glucose metabolism.

Invasiveness of pituitary adenoma is the main cause of its poor prognosis, mechanism of which remains largely unknown. In this study, the differential proteins between invasive and non-invasive pituitary tumors (IPA and NIPA) were identified by TMT labeled quantitative proteomics. The differential metabolites in venous bloods from patients with IPA and NIPA were analyzed by untargeted metabolomics. Proteomic data showed that the top five up-regulated proteins were AD021, C2orf15, PLCXD3, HIST3H2BB and POU1F1, and the top five down-regulated proteins were AIPL1, CALB2, GLUD2, SLC4A10 and GTF2I. Metabolomic data showed that phosphatidylinositol (PI) was most remarkably up-regulated and melibiose was most obviously down-regulated. Further investigation demonstrated that PI stimulation increased the expression of PITPNM1, POU1F1, C2orf15 and LDHA as well as the phosphorylation of AKT and ERK, and promoted the proliferation, migration and invasion of GH3 cells, which were blocked by PITPNM1knockdown. Inhibiting AKT phosphorylation reduced the expression of POU1F1, C2orf15 and LDHA in PI-stimulated cells while activating AKT increased their expression in PITPNM1-silencing cells, which was similar to the function of ERK. POU1F1 silence suppressed the expression of LDHA and C2orf15. Luciferase report assay and ChIP assay demonstrated that POU1F1 positively regulated the transcription of LDHA and C2orf15. In addition, PI propelled the metastasis of GH3 cells in vivo, and elevated the expression of PITPNM1, POU1F1, C2orf15 and LDHA. These results suggested that elevated serum PI might contribute to the proliferation and invasion of pituitary adenoma by regulating the expression of PITPNM1/AKT/ERK/POU1F1 axis.

Background: Six-transmembrane epithelial antigen of prostate 3 (STEAP3), an essential constituent of the STEAP family protein, plays a notable role in promoting cancer proliferation and metastasis. Despite the importance of the STEAP gene family in tumor progression, the function of STEAP3 in cervical cancer (CC) remains unclear.

Materials and methods: The expression of STEAP3 protein in CC tissues and cell lines was identified using immunohistochemistry. The Reduced Representation Bisulfite Sequencing (RRBS) was used to detect global gene DNA methylation in CC tissues and paracancerous tissues. Cell viability, proliferation, migration, and invasion, were evaluated using the Cell Counting Kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU), wound repair assay, and transwell assay, respectively. RNA sequencing was applied to explore STEAP3-related signaling pathways. Western blotting was performed to detect the expression of related proteins, including epithelial-mesenchymal transition (EMT) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling markers.

Results: Herein, STEAP3 was strongly expressed in CC tissues and associated with poor prognosis. CC samples exhibited lower levels of STEAP3 methylation than normal samples, and the methylation levels of CpG islands in STEAP3 were association with prognosis. In contrast to control group, STEAP3 knockdown suppressed the proliferation and invasion of CC cells and enhanced sensitivity to oxaliplatin. Silencing of STEAP3 led to reduced N-cadherin and vimentin levels and increased E-cadherin expression. RNA sequencing analysis suggested that STEAP3 mediated the activation of the JAK STAT3 signaling pathway. Additionally, inhibition of STEAP3 decreased the phosphorylation of JAK2 and STAT3. Interestingly, colivelin (a STAT3 activator) modified STEAP3-induced cell proliferation, invasion, and expression of related proteins in the EMT and JAK/STAT3 signaling pathway.

Conclusion: STEAP3 was significantly associated with CC progression mediated via the JAK/STAT3 signaling pathway and may serve as an effective therapeutic target.

Heterozygosity for loss-of-function alleles of the genes encoding the four subunits of succinate dehydrogenase (SDHA, SDHB, SDHC, SDHD), as well as the SDHAF2 assembly factor predispose affected individuals to pheochromocytoma and paraganglioma (PPGL), two rare neuroendocrine tumors that arise from neural crest-derived paraganglia. Tumorigenesis results from loss of the remaining functional SDHx gene copy, leading to a cell with no functional SDH and a defective tricarboxylic acid (TCA) cycle. It is believed that the subsequent accumulation of succinate competitively inhibits multiple dioxygenase enzymes that normally suppress hypoxic signaling and demethylate histones and DNA, ultimately leading to increased expression of genes involved in angiogenesis and cell proliferation. Why SDH loss is selectively tumorigenic in neuroendocrine cells remains poorly understood. In the absence of SDH-loss tumor-derived cell models, the cellular burden of SDH loss and succinate accumulation have been investigated through conditional knockouts of SDH subunits in pre-existing murine or human cell lines with varying degrees of clinical relevance. Here we characterize two available murine SDH-loss cell lines, immortalized adrenally-derived premature chromaffin cells vs. immortalized fibroblasts, at a level of detail beyond that currently reported in the literature and with the intention of laying the foundation for future investigations into adaptive pathways and vulnerabilities in SDH-loss cells. We report different mechanistic and phenotypic manifestations of SDH subunit loss in the presented cellular contexts. These findings highlight similarities and differences in the cellular response to SDH loss between the two cell models. We show that adrenally-derived cells display more severe morphological cellular and mitochondrial alterations, yet are unique in preserving residual Complex I function, perhaps allowing them to better tolerate SDH loss, thus making them a closer model to SDH-loss PPGL relative to fibroblasts.(281 words).

Background: Amino acids are critical to tumor survival. Tumors can acquire amino acids from the surrounding microenvironment, including the serum. Limiting dietary amino acids is suggested to influence their serum levels. Further, a plant-based diet is reported to contain fewer amino acids than an animal-based diet. The extent to which a plant-based diet lowers the serum levels of amino acids in patients with cancer is unclear.

Methods: Patients with metastatic breast cancer (n = 17) were enrolled in a clinical trial with an ad libitum whole food, plant-based diet for 8 weeks without calorie or portion restriction. Dietary changes by participants were monitored using a three-day food record. Serum was collected from participants at baseline and 8 weeks. Food records and serum were analyzed for metabolic changes.

Results: We found that a whole food, plant-based diet resulted in a lower intake of calories, fat, and amino acids and higher levels of fiber. Additionally, body weight, serum insulin, and IGF were reduced in participants. The diet contained lower levels of essential and non-essential amino acids, except for arginine (glutamine and asparagine were not measured). Importantly, the lowered dietary intake of amino acids translated to reduced serum levels of amino acids in participants (5/9 essential amino acids; 4/11 non-essential amino acids).

Conclusions: These findings provide a tractable approach to limiting amino acid levels in persons with cancer. This data lays a foundation for studying the relationship between amino acids in patients and tumor progression. Further, a whole-food, plant-based diet has the potential to synergize with cancer therapies that exploit metabolic vulnerabilities.

Trial registration: The clinical trial was registered with ClinicalTrials.gov identifier NCT03045289 on 2017-02-07.

Background: The efficacy of tyrosine kinase inhibitors (TKIs) targeting the EGFR is limited due to the persistence of drug-tolerant cell populations, leading to therapy resistance. Non-genetic mechanisms, such as metabolic rewiring, play a significant role in driving lung cancer cells into the drug-tolerant state, allowing them to persist under continuous drug treatment.

Methods: Our study employed a comprehensive approach to examine the impact of the glycolytic regulator 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB3) on the adaptivity of lung cancer cells to EGFR TKI therapies. We conducted metabolomics to trace glucose rerouting in response to PFKFB3 inhibition during TKI treatment. Live cell imaging and DCFDA oxidation were used to quantify levels of oxidation stress. Immunocytochemistry and Neutral Comet assay were employed to evaluate DNA integrity in response to therapy-driven oxidative stress.

Results: Our metabolic profiling revealed that PFKFB3 inhibition significantly alters the metabolic profile of TKI-treated cells. It limited glucose utilization in the polyol pathway, glycolysis, and TCA cycle, leading to a depletion of ATP levels. Furthermore, pharmacological inhibition of PFKFB3 overcome TKI-driven redox capacity by diminishing the expression of glutathione peroxidase 4 (GPX4), thereby exacerbating oxidative stress. Our study also unveiled a novel role of PFKFB3 in DNA oxidation and damage by controlling the expression of DNA-glycosylases involved in base excision repair. Consequently, PFKFB3 inhibition improved the cytotoxicity of EGFR-TKIs by facilitating ROS-dependent cell death.

Conclusions: Our results suggest that PFKFB3 inhibition reduces glucose utilization and DNA damage repair, limiting the adaptivity of the cells to therapy-driven oxidative stress and DNA integrity insults. Inhibiting PFKFB3 can be an effective strategy to eradicate cancer cells surviving under EGFR TKI therapy before they enter the drug-resistant state. These findings may have potential implications in the development of new therapies for drug-resistant cancer treatment.

Introduction: Benzo[a]pyrene (BaP) is a toxic polycyclic aromatic hydrocarbon known as an exogenous AhR ligand. This study investigates the role of BaP in inducing immune checkpoint expression in lung adenocarcinoma (LUAD) and the underlying mechanisms involving the aryl hydrocarbon receptor (AhR) and tryptophan (Trp) metabolism.

Methods: We assessed the expression of immune checkpoint molecules, including PD-L1 and ICOSL, in lung epithelial cell lines (BEAS-2B and H1975) exposed to BaP. The involvement of AhR in BaP-induced immune checkpoint expression was examined using AhR silencing (siAhR). Additionally, the role of Trp metabolism in BaP-mediated immune evasion was explored through culturing in Trp (-/+) condition media, treatments with the inhibitors of rate-limiting enzymes in Trp metabolism (TDO2 and IDO1) and analyses of Trp-catabolizing enzymes. The therapeutic potential of targeting Trp metabolism, specifically TDO2, was evaluated in vivo using C57BL/6 mice orthotopically inoculated with LUAD cells.

Results: BaP exposure significantly upregulated the mRNA and surface expression of PD-L1 and ICOSL, with AhR playing a crucial role in this induction. Trp metabolism was found to enhance BaP-mediated immune evasion, as indicated by stronger induction of immune checkpoints in Trp (+) media and the upregulation of Trp-catabolizing enzymes. TDO2 inhibition markedly suppressed the surface expression of PD-L1 and ICOSL, demonstrating the importance of Trp metabolism in BaP-induced immune evasion. Further analysis confirmed the high TDO2 expression in lung adenocarcinoma and its association with poor patient survival. Using an orthotopic implantation mouse model, we demonstrated the inhibitory effect of two different TDO2 inhibitors on tumorigenesis, immune checkpoints, and tryptophan metabolism.

Conclusions: This study highlights the key mechanisms behind BaP-induced immune evasion in LUAD, particularly through the TDO2/AhR axis. It reveals how TDO2 inhibitors can counteract immune checkpoint activation and boost anti-tumor immunity, suggesting new paths for targeted lung cancer immunotherapy. The findings significantly improve our understanding of immune evasion in LUAD and underscore the therapeutic promise of TDO2 inhibition.

Background: Glioblastoma is an aggressive cancer that originates from abnormal cell growth in the brain and requires metabolic reprogramming to support tumor growth. Metabolic reprogramming involves the upregulation of various metabolic pathways. Although the activation of specific metabolic pathways in glioblastoma cell lines has been documented, the comprehensive profile of metabolic reprogramming and the role of each pathway in glioblastoma tissues in patients remain elusive.

Methods: We analyzed 38 glioblastoma tissues. As a test set, we examined 20 tissues from Kyushu University Hospital, focusing on proteins related to several metabolic pathways, including glycolysis, the one-carbon cycle, glutaminolysis, and the mitochondrial tricarboxylic acid cycle. Subsequently, we analyzed an additional 18 glioblastoma tissues from Kagoshima University Hospital as a validation set. We also validated our findings using six cell lines, including U87, LN229, U373, T98G, and two patient-derived cells.

Results: The levels of mitochondria-related proteins (COX1, COX2, and DRP1) were correlated with each other and with glutaminolysis-related proteins (GLDH and GLS1). Conversely, their expression was inversely correlated with that of glycolytic proteins. Notably, inhibiting the glutaminolysis pathway in cell lines with high GLDH and GLS1 expression proved effective in suppressing tumor growth.

Conclusions: Our findings confirm that glioblastoma tissues can be categorized into glycolytic-dominant and mitochondrial-dominant types, as previously reported. The mitochondrial-dominant type is also glutaminolysis-dominant. Therefore, inhibiting the glutaminolysis pathway may be an effective treatment for mitochondrial-dominant glioblastoma.

Background: The metabolic pathway of de novo lipogenesis (DNL) is upregulated in fatty liver disease and liver cancer. Inhibitors of DNL are in development for the treatment of these disorders; however, our previous study showed that blocking DNL unexpectedly exacerbated liver tumorigenesis when liver acetyl-CoA carboxylase (ACC) 1 and 2 enzymes were deleted in mice treated with diethylnitrosamine (DEN) and fed high fat diet. Herein, we used 3 new approaches including ACC1 vs. ACC2 isotype-selective inhibition, delaying ACC inhibition until after carcinogen treatment, and feeding mice normal chow diet to better understand the impact of ACC inhibition on liver tumorigenesis.

Methods: Six genotypes of female C57BL/6J mice with floxed ACC1 and/or ACC2 alleles were injected with DEN at 2 weeks of age followed by liver-specific knockout of ACC genes at 9 weeks. Mice were fed a normal chow diet and evaluated at 52 weeks for liver tumours.

Results: Compared to the wildtype control group, no genotype decreased tumour multiplicity or burden; however, mice completely lacking liver ACC1 and ACC2 had > 5-fold increases in liver tumour multiplicity and burden.

Conclusion: ACC inhibition exacerbated DEN-induced liver tumorigenesis only when both ACC isotypes were completely inhibited. The pro-tumour phenotype of ACC inhibition was strongly reproducible irrespective of chow or high fat feeding, and irrespective of ACC inhibition prior to or after DEN treatment. Retaining partial ACC activity at either isotype prevented tumour exacerbation in mice at risk for developing liver tumours.

Chemoresistance remains a major challenge in the effective treatment of colorectal cancer (CRC), contributing to poor patient outcomes. While the molecular mechanisms underlying chemoresistance are complex and multifaceted, emerging evidence suggests that altered mitochondrial function and hormone signaling play crucial roles. In this study, we investigated the role of CYP19A1, a key enzyme in estrogen biosynthesis, in regulating chemoresistance in CRC. Using a combination of in vitro functional assays, transcriptomic analysis, and clinical data mining, we demonstrate that CYP19A1 expression is significantly upregulated in CRC cells and patient-derived samples compared to normal controls. Mechanistically, we found that CYP19A1 regulates chemoresistance through modulation of mitochondrial function and complex I activity, which is mediated by CYP19A1-dependent estrogen biosynthesis. Notably, targeted inhibition of CYP19A1 and complex I using specific inhibitors effectively reversed the chemoresistance of CRC cells to chemotherapeutic drugs. Moreover, analysis of the TCGA CRC dataset revealed that high CYP19A1 expression correlates with poor overall survival in chemotherapy-treated patients. Taken together, our findings uncover a novel role for CYP19A1 in regulating chemoresistance in CRC through modulation of mitochondrial function and estrogen signaling, and highlight the potential of targeting the CYP19A1/estrogen/complex I axis as a therapeutic strategy to overcome chemoresistance and improve patient outcomes.