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Per capita fructose consumption has increased 100-fold over the last century1. Epidemiological studies suggest that excessive fructose consumption, and especially consumption of sweet drinks, is associated with hyperlipidaemia, non-alcoholic fatty liver disease, obesity and diabetes2–7. Fructose metabolism begins with its phosphorylation by the enzyme ketohexokinase (KHK), which exists in two alternatively spliced forms8. The more active isozyme, KHK-C, is expressed most strongly in the liver, but also substantially in the small intestine9,10 where it drives dietary fructose absorption and conversion into other metabolites before fructose reaches the liver11–13. It is unclear whether intestinal fructose metabolism prevents or contributes to fructose-induced lipogenesis and liver pathology. Here we show that intestinal fructose catabolism mitigates fructose-induced hepatic lipogenesis. In mice, intestine-specific KHK-C deletion increases dietary fructose transit to the liver and gut microbiota and sensitizes mice to fructose’s hyperlipidaemic effects and hepatic steatosis. In contrast, intestine-specific KHK-C overexpression promotes intestinal fructose clearance and decreases fructose-induced lipogenesis. Thus, intestinal fructose clearance capacity controls the rate at which fructose can be safely ingested. Consistent with this, we show that the same amount of fructose is more strongly lipogenic when drunk than eaten, or when administered as a single gavage, as opposed to multiple doses spread over 45 min. Collectively, these data demonstrate that fructose induces lipogenesis when its dietary intake rate exceeds the intestinal clearance capacity. In the modern context of ready food availability, the resulting fructose spillover drives metabolic syndrome. Slower fructose intake, tailored to intestinal capacity, can mitigate these consequences. Modulating the capacity of the intestinal epithelium to catabolize fructose is shown to alter fructose-induced lipogenesis in the mouse liver, suggesting that fructose clearance in the small intestine protects from steatosis.

To compare the survival benefit between preoperative and postoperative radiotherapy for stage I–III non-inflammatory breast cancer patients, we conducted a retrospective cohort study using surveillance, epidemiology and end results databases. Our study recruited patients who had been diagnosed with stage I–III breast cancer and underwent surgery and radiotherapy. The overall survival was calculated by Kaplan–Meier method. Cox risk model was used to determine the impact of radiotherapy according to stage, molecular subtype and other risk factors. Propensity score matching was used to balance measurable confounding factors. Of all the 411,279 enrolled patients varying from 1975 to 2016, 1712 patients received preoperative radiotherapy, and 409,567 patients received postoperative radiotherapy. Compared with the postoperative radiotherapy group, the preoperative radiotherapy group showed significantly higher risks of overall mortality and breast cancer-specific mortality. Survival differences in treatment sequences were correlated with stage, molecular subtypes and other risk factors. According to the results of this study, preoperative radiotherapy did not show a survival advantage, and postoperative radiotherapy is still the primary treatment. However, preoperative radiotherapy also has some theoretical advantages, such as phase reduction and recurrence reduction. Therefore, it is still worthy of further exploration.

Background: The optimal therapeutic strategy in locally advanced esophageal squamous cell carcinoma (ESCC) primarily treated by surgery remains unknown. This study was designed to evaluate the impact of postoperative chemoradiotherapy and postoperative sequential chemoradiotherapy on survival in this population. Methods: The study included a total of 228 consecutive patients who underwent radical esophagectomy and were confirmed to have stage pT3–4 or pN+ ESCC from September 2011 to September 2017 at our institution. All patients received postoperative radiotherapy with or without concurrent or sequential chemotherapy after esophagectomy. Univariate and multivariate analyses were used to compare the survival of patients with postoperative radiotherapy, postoperative concurrent chemoradiotherapy, and postoperative sequential chemoradiotherapy. Results: After a median follow-up of 52 months, the 3- and 5-year overall survival (OS) rates were 70.2% [95% confidence interval (CI), 63.7–76.7%] and 62.2% (95% CI, 54.6–69.8%), respectively. The disease-free survival (DFS) rates at 3 and 5 years were 65.2% (95% CI, 58.7–71.7%) and 55.2% (95% CI, 47.6–62.8%), respectively. The 3- and 5-year locoregional recurrence-free survival (LRFS) rates were 65.1% (95% CI, 58.4–71.8%) and 55.5% (95% CI, 47.7–63.3%). Of the 228 patients, 38 (16.7%) had distant metastases. Subgroup analysis showed that being male and having a higher T stage were independent poor prognostic factors for OS and DFS in patients with pN+ or stage III + IVA ESCC. The results also showed that in patients with stage III + IVA ESCC, the DFS of the patients in the concurrent chemotherapy (CCT) group was improved compared with that in the no CCT group [hazard ratio (HR), 0.551; 95% CI, 0.323–0.938; P=0.028]. Multivariate analysis showed that sequential chemoradiotherapy was associated with poor LRFS (HR, 2.312; 95% CI, 1.078–4.959; P=0.031), especially in stage T3–4 patients, and it was also related to the poor DFS (HR, 1.781; 95% CI, 1.086–2.921; P=0.022) in patients with stage T3–4 ESCC. Conclusions: In patients with locally advanced ESCC, those who underwent sequential chemoradiotherapy had a worse LRFS. Postoperative concurrent chemoradiotherapy was the most effective adjuvant therapy for resected stage III–IVA ESCC. In addition, being male, having a higher T stage, and being node-positive were independent poor prognostic factors for OS and DFS.

Contralateral axillary lymph node metastasis (CAM) in breast cancer is rare, and the reason is unclear. CAM may be found at the time of primary breast cancer diagnosis or following primary tumor treatment. CAM staging and treatment methods are controversial. Hence, we summarized the features of CAM patients and explored the therapeutic options. We report the case of an 82-year-old woman with right breast cancer accompanied by CAM. The records of breast cancer patients with CAM in PubMed (January 2000-May 2020) were also reviewed. After undergoing comprehensive treatments (neoadjuvant chemotherapy, surgery, radiotherapy, endocrine therapy, and targeted therapy), no signs of recurrence and metastasis were noted during the 25-month follow-up. Overall, 17 studies (36 patients) were selected for the review, of which 15 had synchronous CAM and 21 had metachronous CAM. Nineteen of 22 patients had histologic grade 3. Forty percent (12/30) had ≥4 positive lymph nodes. Among these 36 patients, 9 had triple-negative breast cancers, and 9 were human epidermal growth factor receptor 2 positive. Among the 30 patients staged, 6 (20%) were in stage I; 7 (23.33%), stage II; and 17 (56.67%), stage III. Two patients received systemic therapy, while one received an unknown treatment. The remaining 33 patients all received local treatment (surgery or radiotherapy). The survival time of synchronous and metachronous CAM patients was 12-72 months with the death rate of 1/7 and 12-144 months with that of 3/12, respectively. CAM may be a regional manifestation rather than a distant metastasis. Comprehensive treatment, including surgery and radiotherapy, may provide better control.

Background To determine the diagnostic accuracy of preoperative T/N stage with magnetic resonance imaging (MRI) in lower and middle rectal cancer patients and the impacts on clinical decision‐making. Patients and methods A total of 211 patients were recruited from October 2015 to March 2017 in this retrospective study. High‐resolution MRI was performed within 2 weeks before surgery. Histopathologic results were evaluated for the postoperative T/N stage and the diagnostic accuracy of MRI was assessed according to the postoperative histopathologic results. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value were evaluated for T/N staging and κ values were used to evaluate MRI consistent analysis compared with postoperative histopathologic staging. Results The overall MRI diagnostic accuracy was 79.62% for T1‐4 staging and 54.50% for N0‐2 staging. The κ values were 0.619 and 0.255 for T1‐4 and N0‐2 staging, respectively. The diagnostic accuracy of MRI for treatment decision‐making was 80.57%. Conclusion MRI allows a highly accurate preoperative assessment of T stage but only a fairly accurate preoperative assessment of N stage for rectal cancer. The diagnostic accuracy of MRI for treatment decision‐making is promising, but additional studies are needed to validate these findings in a larger sample size from multiple centers.

NADH provides electrons for aerobic ATP production. In cells deprived of oxygen or with impaired electron transport chain activity, NADH accumulation can be toxic. To minimize such toxicity, elevated NADH inhibits the classical NADH producing pathways: glucose, glutamine, and fat oxidation. Here, through deuterium tracing studies in cultured cells and mice, we show that folate-dependent serine catabolism also produces substantial NADH. Strikingly, when respiration is impaired, serine catabolism through methylene tetrahydrofolate dehydrogenase (MTHFD2) becomes a major NADH source. In cells whose respiration is slowed by hypoxia, metformin, or genetic lesions, mitochondrial serine catabolism inhibition partially normalizes NADH levels and facilitates cell growth. In mice with engineered mitochondrial complex I deficiency (NDUSF4-/-), serine’s contribution to NADH is elevated and progression of spasticity is modestly slowed by pharmacological blockade of serine degradation. Thus, when respiration is impaired, serine catabolism contributes to toxic NADH accumulation.

Background Endometrial cancer (UCEC) is a complex malignant tumor characterized by both genetic level and clinical trial. Patients with UCEC exhibit the similar clinical features, however, they have distinct outcomes due to molecular heterogeneity. The aim of this study was to access the prognostic value of long non-coding RNAs (lncRNAs) in UCEC patients and to identify potential lncRNA signature for predicting patients’ survival and improving patient-tailored treatment. Methods We performed a comprehensive genome-wide analysis of lncRNA expression profiles and clinical data in a large cohort of 301 UCEC patients. UCEC patients were randomly divided into the discovery cohort (n = 150) and validation cohort (n = 151). A novel lncRNA-focus expression signature was identified in the discovery cohort, and independently accessed in the validation cohort. Additionally, the lncRNA signature was evaluated by multivariable Cox regression and stratification analysis as well as functional enrichment analysis. Results We detected a novel lncRNA-focus expression signature (LFES) consisting of 11 lncRNAs that were associated with survival based on risk scoring strategy in UCEC. The risk score based on the LFES was able to separate patients of discovery cohort into high-risk and low-risk groups with significantly different overall survival and progression-free survival, and has been successfully confirmed in the validation cohort. Furthermore, the LFES is an independent prognostic predictor of survival and demonstrates superior prognostic performance compared with the clinical covariates for predicting 5-year survival (AUC = 0.887). Functional analysis has linked the expression of prognostic lncRNAs to well-known tumor suppressor or ontogenetic pathways in endometrial carcinogenesis. Conclusions Our study revealed a novel 11-lncRNA signature to predict survival of UCEC patient. This lncRNA signature may be a valuable and alternative marker for risk evaluation to aid patient-tailored treatment and improve the outcome of patients with UCEC. Electronic supplementary material The online version of this article (10.1186/s12885-017-3983-0) contains supplementary material, which is available to authorized users.

Chemical de-caging has emerged as an attractive strategy for gain-of-function study of proteins via small-molecule reagents. The previously reported chemical de-caging reactions have been largely centered on liberating the side chain of lysine on a given protein. Herein, we developed an allene-based caging moiety and the corresponding palladium de-caging reagents for chemical rescue of tyrosine (Tyr) activity on intracellular proteins. This bioorthogonal de-caging pair has been successfully applied to unmask enzymatic Tyr sites (e.g., Y671 on Taq polymerase and Y728 on Anthrax lethal factor) as well as the post-translational Tyr modification site (Y416 on Src kinase) in vitro and in living cells. Our strategy provides a general platform for chemical rescue of Tyr-dependent protein activity inside cells.

NADPH donates high-energy electrons for antioxidant defence and reductive biosynthesis. Cytosolic NADP is recycled to NADPH by the oxidative pentose-phosphate pathway (oxPPP), malic enzyme 1 (ME1) and isocitrate dehydrogenase 1 (IDH1). Here we show that any one of these routes can support cell growth, but the oxPPP is uniquely required to maintain a normal NADPH/NADP ratio, mammalian dihydrofolate reductase (DHFR) activity and folate metabolism. These findings are based on CRISPR deletions of glucose-6-phosphate dehydrogenase (G6PD, the committed oxPPP enzyme), ME1, IDH1 and combinations thereof in HCT116 colon cancer cells. Loss of G6PD results in high NADP, which induces compensatory increases in ME1 and IDH1 flux. But the high NADP inhibits DHFR, resulting in impaired folate-mediated biosynthesis, which is reversed by recombinant expression of Escherichia coli DHFR. Across different cancer cell lines, G6PD deletion produced consistent changes in folate-related metabolites, suggesting a general requirement for the oxPPP to support folate metabolism. The oxidative pentose-phosphate pathway (oxPPP) is a major NADPH producer. Here the authors show that malic enzyme or isocitrate dehydrogenase can support the growth of cells lacking the oxPPP, but the oxPPP is necessary to maintain a normal NADPH/NADP ratio, DHFR activity and folate metabolism.

Background To determine the diagnostic accuracy of preoperative T/N stage using MRI in lower and middle rectal cancer patients and the impacts on clinical decision-making. Patients and methods There were 354 patients recruited from May 2017 to February 2019. MRI was performed within 2 weeks before surgery. Histopathologic results were evaluated for the postoperative T/N stage and MRI diagnostic accuracy was assessed based on the postoperative histopathologic results. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and Kappa values were used to evaluate MRI diagnostic accuracy and analysis consistency compared with postoperative histopathologic staging. Results Overall MRI diagnostic accuracy was 78.2% and 56.8% for T1–4 and N0–2 staging. The Kappa values were 0.625 and 0.323 for T1–4 and N0–2 staging, respectively. After combination, MRI diagnostic accuracy was 85% and 69.5% for T and N staging. The Kappa values were 0.693 and 0.4 for T and N staging. The diagnostic accuracy of MRI for treatment decision-making was 79.1%. Conclusion MRI enables a highly accurate preoperative assessment of T stage but only a fairly accurate preoperative assessment of the N stage for rectal cancer with surgery. The diagnostic accuracy of MRI for treatment decision-making is promising.

Much understanding of metabolism is based on monitoring chemical reactions in cells with isotope tracers. For this purpose, 13C is well suited due to its stable incorporation into bio-molecules and minimal kinetic isotope effect. For redox reactions, however, deuterium tracing can provide valuable additional information. To date, studies examining NADPH production with deuterated carbon sources have failed to account for roughly half of NADPH’s redox active hydrogen. Here we show that the missing hydrogen is the result of enzyme-catalyzed H-D exchange between water and NADPH. While isolated NADPH does not undergo H-D exchange with water, such exchange is catalyzed by Flavin enzymes and occurs rapidly in cells. Correction for H-D exchange is required for accurate assessment of the biological sources of NADPH’s high energy electrons. Deuterated water (D2O) is frequently used to monitor fat synthesis in vivo, but the chemical pathway of the deuteron into fat remains unclear. We show that D2O labels fatty acids primarily via NADPH. Knowledge of this labeling route enables calculation, without any fitting parameters, of the mass isotope distributions of fatty acids from cells grown in D2O. Thus, knowledge of enzyme-catalyzed H-D exchange between water and NADPH enables chemically accurate interpretation of deuterium tracing studies of redox cofactor and fatty acid metabolism.

Recent studies have demonstrated the utility and superiority of long non-coding RNAs (lncRNAs) as novel biomarkers for cancer diagnosis, prognosis, and therapy. In the present study, the prognostic value of lncRNAs in glioblastoma multiforme was systematically investigated by performing a genome-wide analysis of lncRNA expression profiles in 419 glioblastoma patients from The Cancer Genome Atlas (TCGA) project. Using survival analysis and Cox regression model, we identified a set of six lncRNAs (AC005013.5, UBE2R2-AS1, ENTPD1-AS1, RP11-89C21.2, AC073115.6, and XLOC_004803) demonstrating an ability to stratify patients into high- and low-risk groups with significantly different survival (median 0.899 vs. 1.611 years, p = 3.87e−09, log-rank test) in the training cohort. The six-lncRNA signature was successfully validated on independent test cohort of 219 patients with glioblastoma, and it revealed superior performance for risk stratification with respect to existing lncRNA-related signatures. Multivariate Cox and stratification analysis indicated that the six-lncRNA signature was an independent prognostic factor after adjusting for other clinical covariates. Further in silico functional analysis suggested that the six-lncRNA signature may be involved in the immune-related biological processes and pathways which are very well known in the context of glioblastoma tumorigenesis. The identified lncRNA signature had important clinical implication for improving outcome prediction and guiding the tailored therapy for glioblastoma patients with further prospective validation.

Deregulation of long non-coding RNAs (lncRNAs) expression has been proven to be involved in the development and progression of cancer. However, expression pattern and prognostic value of lncRNAs in breast cancer recurrence remain unclear. Here, we analyzed lncRNA expression profiles of breast cancer patients who did or did not develop recurrence by repurposing existing microarray datasets from the Gene Expression Omnibus database, and identified 12 differentially expressed lncRNAs that were closely associated with tumor recurrence of breast cancer patients. We constructed a lncRNA-focus molecular signature by the risk scoring method based on the expression levels of 12 relapse-related lncRNAs from the discovery cohort, which classified patients into high-risk and low-risk groups with significantly different recurrence-free survival (HR = 2.72, 95% confidence interval 2.07–3.57; p = 4.8e-13). The 12-lncRNA signature also represented similar prognostic value in two out of three independent validation cohorts. Furthermore, the prognostic power of the 12-lncRNA signature was independent of known clinical prognostic factors in at least two cohorts. Functional analysis suggested that the predicted relapse-related lncRNAs may be involved in known breast cancer-related biological processes and pathways. Our results highlighted the potential of lncRNAs as novel candidate biomarkers to identify breast cancer patients at high risk of tumor recurrence.

Long non-coding RNAs (lncRNAs) represent an emerging layer of cancer biology and have been implicated in the development and progression of cancers. However, the prognostic significance of lncRNAs in diffuse large-B-cell lymphoma (DLBCL) remains unclear and needs to be systematically investigated. In this study, we obtained and analyzed lncRNA expression profiles in three cohorts of 1043 DLBCL patients by repurposing the publicly available microarray datasets from the Gene Expression Omnibus (GEO) database. In the discovery series of 207 patients, we identified a set of six lncRNAs that was significantly associated with patients’ overall survival (OS) using univariate Cox regression analysis. The six prognostic lncRNAs were combined to form an expression-based six-lncRNA signature which classified patients of the discovery series into the high-risk group and low-risk group with significantly different survival outcome (HR = 2.31, 95% CI = 1.8 to 2.965, p

We herein report a chemical decaging strategy for the in situ generation of neuramic acid (Neu), a unique type of sialic acid, on live cells by the use of a palladium-mediated bioorthogonal elimination reaction. Palladium nanoparticles (Pd NPs) were found to be a highly efficient and biocompatible depropargylation catalyst for the direct conversion of metabolically incorporated N-(propargyloxycarbonyl)neuramic acid (Neu5Proc) into Neu on cell-surface glycans. This conversion chemically mimics the enzymatic de-N-acetylation of N-acetylneuramic acid (Neu5Ac), a proposed mechanism for the natural occurrence of Neu on cell-surface glycans. The bioorthogonal elimination was also exploited for the manipulation of cell-surface charge by unmasking the free amine at C5 to neutralize the negatively charged carboxyl group at C1 of sialic acids.

The INK4b-ARF-INK4a gene cluster encodes three tumor suppressors: p15(INK4b), p14(ARF), and p16(INK4a). Antisense non-coding RNA in the INK4 locus (ANRIL) is transcribed in the opposite direction from this gene cluster. Recent studies suggest that ANRIL represses the expression of p15(INK4b), p14(ARF), and p16(INK4a); however, the underlying mechanism is unclear. In this study, the expressions of ANRIL in human esophageal squamous cell carcinoma (ESCC) tissues and matched adjacent non-tumor tissues were examined by quantitative real-time polymerase chain reaction. Compared with matched adjacent non-tumor tissues, the expression levels of ANRIL in ESCC tissues were significantly increased. Furthermore, inhibition of ANRIL was found to increase the expression of p15(INK4b) and transforming growth factor β1 (TGFβ1) and depletion of ANRIL in ESCC cell lines may inhibit cellular proliferation. Thus, our findings suggest a significant role of ANRIL in the occurrence and development of ESCC through TGFβ1 signaling pathways.

Glucose is catabolized by two fundamental pathways, glycolysis to make ATP and the oxidative pentose phosphate pathway to make reduced nicotinamide adenine dinucleotide phosphate (NADPH). The first step of the oxidative pentose phosphate pathway is catalyzed by the enzyme glucose-6-phosphate dehydrogenase (G6PD). Here we develop metabolite reporter and deuterium tracer assays to monitor cellular G6PD activity. Using these, we show that the most widely cited G6PD antagonist, dehydroepiandosterone, does not robustly inhibit G6PD in cells. We then identify a small molecule (G6PDi-1) that more effectively inhibits G6PD. Across a range of cultured cells, G6PDi-1 depletes NADPH most strongly in lymphocytes. In T cells but not macrophages, G6PDi-1 markedly decreases inflammatory cytokine production. In neutrophils, it suppresses respiratory burst. Thus, we provide a cell-active small molecule tool for oxidative pentose phosphate pathway inhibition, and use it to identify G6PD as a pharmacological target for modulating immune response.