Hepatic glucokinase regulatory protein and carbohydrate response element binding protein attenuation reduce de novo lipogenesis but do not mitigate intrahepatic triglyceride accumulation in Aldob deficiency.

OBJECTIVE: Stable isotope studies have shown that hepatic de novo lipogenesis (DNL) plays an important role in the pathogenesis of intrahepatic lipid (IHL) deposition. Furthermore, previous research has demonstrated that fructose 1-phosphate (F1P) not only serves as a substrate for DNL, but also acts as a signalling metabolite that stimulates DNL from glucose. The aim of this study was to elucidate the mediators of F1P-stimulated DNL, with special focus on two key regulators of intrahepatic glucose metabolism, i.e., glucokinase regulatory protein (GKRP) and carbohydrate response element binding protein (ChREBP). METHODS: Aldolase B deficient mice (Aldob-/-), characterized by hepatocellular F1P accumulation, enhanced DNL, and hepatic steatosis, were either crossed with GKRP deficient mice (Gckr-/-) or treated with short hairpin RNAs directed against hepatic ChREBP. RESULTS: Aldob-/- mice showed higher rates of de novo palmitate synthesis from glucose when compared to wildtype mice (p < 0.001). Gckr knockout reduced de novo palmitate synthesis in Aldob-/- mice (p = 0.017), without affecting the hepatic mRNA expression of enzymes involved in DNL. In contrast, hepatic ChREBP knockdown normalized the hepatic mRNA expression levels of enzymes involved in DNL and reduced fractional DNL in Aldob-/- mice (p < 0.05). Of interest, despite downregulation of DNL in response to Gckr and ChREBP attenuation, no reduction in intrahepatic triglyceride levels was observed. CONCLUSIONS: Both GKRP and ChREBP mediate F1P-stimulated DNL in aldolase B deficient mice. Further studies are needed to unravel the role of GKRP and hepatic ChREBP in regulating IHL accumulation in aldolase B deficiency.

A Case Study of a Rare Disease (Fructosemia) Diagnosed in a Patient with Abdominal Pain.

Hereditary fructose intolerance is a rare genetic disorder that is inherited in an autosomal recessive manner, with mutations sometimes occurring spontaneously. Consuming fructose triggers biochemical abnormalities, disrupting liver processes like glycogenolysis and gluconeogenesis. Recent studies have revealed elevated intrahepatic fat levels in affected individuals. Symptoms include aversion to fructose-containing foods, hypoglycemia, liver and kidney dysfunction, and growth delays, with severe cases leading to liver enlargement, fatty liver disease, kidney failure, and life-threatening hypoglycemia. In this case study, we present a 20-month-old child with symptoms including difficulty passing stool, abdominal rigidity, abdominal pain with bloating and hypoglycemia. Initial clinical findings revealed elevated liver enzymes, a mildly enlarged hyperechoic liver, hypercholesterolemia, and borderline alpha-fetoprotein values. Diagnostic assessments identified hereditary fructose intolerance (HFI) with pathogenic variants in the ALDOB gene, along with a diagnosis of celiac disease. Genetic testing of the parents revealed carrier status for pathological aldolase B genes. This case underscores the importance of comprehensive clinical evaluation and genetic testing in pediatric patients with complex metabolic presentations.

Associations between ALDOB polymorphisms and intrahepatic cholestasis of pregnancy susceptibility in the Chinese Han population.

OBJECTIVES: To research the associations between fructose-bisphosphate aldolase B (ALDOB) gene polymorphisms and intrahepatic cholestasis of pregnancy (ICP) risk. MATERIAL AND METHODS: Whole-genome sequencing (WGS) was performed to detect ALDOB polymorphisms. Five web-available tools were employed to predict the effect of the site variant on the protein. Protein structure comparisons between the reference and ALDOB-modified samples were performed by SWISS-MODEL and Chimera 1.14rc, respectively. RESULTS: We identified 28 genetic variants in the ALDOB gene. When the cut-off value of minor allele frequency (MAF) of loci was 0.001 in four databases, five missense variants, including rs747604233, rs759204107, rs758242037, rs371526091 and rs77718928, were reserved for subsequent analysis. These variants were absent from the 1029 control individuals. The influence of all five variants on protein function was predicted to be damaging by the abovementioned five prediction software programs. Bioinformatics analysis demonstrated that these five missense variants were highly conserved among vertebrates. Compared to the wild-type protein structure, all five mutated protein structures showed a slight change in the chemical bond lengths of the enzyme activity domains. The combined clinical data indicate that the variant group had a significantly older age (p = 0.038), a higher level of indirect bilirubin (IDBIL, p = 0.033), and lower counts of white blood cells (WBCs, p = 7.38E-05) and platelets (PLTs, p = 0.018) than the wild-type group. CONCLUSIONS: This is the first study to examine the associations between ALDOB polymorphisms and ICP disease in 249 Chinese patients with ICP. Our present study expands the understanding of the pathogenesis of ICP.

Endogenous Fructose Production and Metabolism Drive Metabolic Dysregulation and Liver Disease in Mice with Hereditary Fructose Intolerance.

Excessive intake of sugar, and particularly fructose, is closely associated with the development and progression of metabolic syndrome in humans and animal models. However, genetic disorders in fructose metabolism have very different consequences. While the deficiency of fructokinase, the first enzyme involved in fructose metabolism, is benign and somewhat desirable, missense mutations in the second enzyme, aldolase B, causes a very dramatic and sometimes lethal condition known as hereditary fructose intolerance (HFI). To date, there is no cure for HFI, and treatment is limited to avoiding fructose and sugar. Because of this, for subjects with HFI, glucose is their sole source of carbohydrates in the diet. However, clinical symptoms still occur, suggesting that either low amounts of fructose are still being consumed or, alternatively, fructose is being produced endogenously in the body. Here, we demonstrate that as a consequence of consuming high glycemic foods, the polyol pathway, a metabolic route in which fructose is produced from glucose, is activated, triggering a deleterious mechanism whereby glucose, sorbitol and alcohol induce severe liver disease and growth retardation in aldolase B knockout mice. We show that generically and pharmacologically blocking this pathway significantly improves metabolic dysfunction and thriving and increases the tolerance of aldolase B knockout mice to dietary triggers of endogenous fructose production.

ALDOB represents a potential prognostic biomarker for patients with clear cell renal cell carcinoma.

Background: Previous studies have shown that aldolase B (ALDOB) might play controversial roles in multiple types of cancer, which could act as a cancer-promoting factor or a cancer-inhibiting factor depending on the subtype of the cancer. However, the role of ALDOB in clear cell renal cell carcinoma (ccRCC) patients has not been clearly elucidated. Therefore, this study aimed to comprehensively explore the expression level, prognostic value, functional enrichment, immune infiltration, and N6-methyladenosine (m6A) modification of ALDOB in ccRCC patients. Methods: A total of 1,070 ccRCC tissues and 409 normal tissues from the Gene Expression Omnibus (GEO) database, The Cancer Genome Atlas (TCGA) database, and the ArrayExpress database were enrolled to evaluate the expression level and prognostic value of ALDOB in ccRCC. The Kaplan-Meier survival curves and the Log-Rank test were performed to assess the prognostic value. The univariate and multivariate Cox regression analysis were used to identify the independent prognostic predictors in ccRCC patients. In addition, R version 4.2.0 with its suitable packages were used to perform the functional enrichment analysis, immune infiltration analysis, and m6A methylation analysis. Statistical significance was set at the P value <0.05. Results: The expression level of ALDOB was significantly down-regulated in ccRCC compared to normal tissue, and the ALDOB expression level was noticeably correlated with T stage, M stage, and histologic grade of patients with ccRCC. The survival analysis revealed that ALODB was the independent predictor of overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS) of ccRCC patients. In addition, the functional enrichment analysis showed that ALDOB and its related genes were mainly involved in the metabolism and metabolic pathways of multiple substances, including glycolysis, gluconeogenesis, and fatty acid degradation. Finally, the immune infiltration analysis and the m6A methylation analysis suggested that ALDOB was closely correlated with the infiltration abundance of immune cells and stromal cells in the tumor microenvironment and several types of m6A regulators in ccRCC. Conclusions: As a potential prognostic biomarker for patients with ccRCC, downregulation of ALDOB was closely associated with the clinicopathological features, poor prognosis, immune infiltration, and m6A modification in ccRCC patients.

Recent Progress on Fructose Metabolism-Chrebp, Fructolysis, and Polyol Pathway.

Excess fructose intake is associated with obesity, fatty liver, tooth decay, cancer, and cardiovascular diseases. Even after the ingestion of fructose, fructose concentration in the portal blood is never high; fructose is further metabolized in the liver, and the blood fructose concentration is 1/100th of the glucose concentration. It was previously thought that fructose was metabolized in the liver and not in the small intestine, but it has been reported that metabolism in the small intestine also plays an important role in fructose metabolism. Glut5 knockout mice exhibit poor fructose absorption. In addition, endogenous fructose production via the polyol pathway has also received attention; gene deletion of aldose reductase (Ar), ketohexokinase (Khk), and triokinase (Tkfc) has been found to prevent the development of fructose-induced liver lipidosis. Carbohydrate response element-binding protein (Chrebp) regulates the expression of Glut5, Khk, aldolase b, and Tkfc. We review fructose metabolism with a focus on the roles of the glucose-activating transcription factor Chrebp, fructolysis, and the polyol pathway.

Identification and evaluation of fructose-bisphosphate aldolase B as a potential diagnostic biomarker in choledochal cysts patients: a quantitative proteomic analysis.

BACKGROUND: Choledochal cyst (CC) is a congenital bile duct malformation, with a higher incidence in minors. Patients with CCs are at risk of pancreatitis and ascending cholangitis. The main forms of treatments aim to avoid any possible hepatic, pancreatic, or biliary complications. Since early diagnosis is of great importance for CC treatment and prognosis, this investigation was designed to screen and identify potential biomarkers from the serum samples of CC patients for CC early diagnosis. METHODS: Quantitative label free proteomic analysis was used to identify differentially expressed proteins in serum samples from CC patients and normal healthy children. The expression levels of biomarker candidates were further confirmed using quantitative polymerase chain reaction (Q-PCR), Western blot analysis, and immunohistochemistry in the choledochal tissues. RESULTS: The quantitative label free proteomic analysis identified 47 differentially expressed proteins in the serum samples from the CC patients and the normal children, including 14 up-regulated proteins and 33 down-regulated proteins. The expression profile of eight biomarker candidates in CC patients, namely, insulin-like growth factor binding protein 2 (IGFBP2), tropomyosin (TPM3), fructose-bisphosphate aldolase B (ALDOB), fumarylacetoacetate hydrolase (FAH), superoxide dismutase 3 (SOD3), secreted protein acidic and cysteine rich (SPARC), apolipoprotein E (APOE), and retinol binding protein 4 (RBP4), were selected for further examination in choledochal tissues, showing that ALDOB was significantly increased. CONCLUSIONS: The results demonstrated that the ALDOB protein increased significantly in choledochal tissues and the serum samples of CC patients, which may serve as an effective predictor for early diagnosis of CC.

Nectar-feeding bats and birds show parallel molecular adaptations in sugar metabolism enzymes.

In most vertebrates, the demand for glucose as the primary substrate for cellular respiration is met by the breakdown of complex carbohydrates, or energy is obtained by protein and lipid catabolism. In contrast, a few bat and bird species have convergently evolved to subsist on nectar, a sugar-rich mixture of glucose, fructose, and sucrose.1-4 How these nectar-feeders have adapted to cope with life-long high sugar intake while avoiding the onset of metabolic syndrome and diabetes5-7 is not understood. We analyzed gene sequences obtained from 127 taxa, including 22 nectar-feeding bat and bird genera that collectively encompass four independent origins of nectarivory. We show these divergent taxa have undergone pervasive molecular adaptation in sugar catabolism pathways, including parallel selection in key glycolytic and fructolytic enzymes. We also uncover convergent amino acid substitutions in the otherwise evolutionarily conserved aldolase B (ALDOB), which catalyzes rate-limiting steps in fructolysis and glycolysis, and the mitochondrial gatekeeper pyruvate dehydrogenase (PDH), which links glycolysis and the tricarboxylic acid cycle. Metabolomic profile and enzyme functional assays are consistent with increased respiratory flux in nectar-feeding bats and help explain how these taxa can both sustain hovering flight and efficiently clear simple sugars. Taken together, our results indicate that nectar-feeding bats and birds have undergone metabolic adaptations that have enabled them to exploit a unique energy-rich dietary niche among vertebrates.

Transferrin Isoforms, Old but New Biomarkers in Hereditary Fructose Intolerance.

Hereditary Fructose Intolerance (HFI) is an autosomal recessive inborn error of metabolism characterised by the deficiency of the hepatic enzyme aldolase B. Its treatment consists in adopting a fructose-, sucrose-, and sorbitol (FSS)-restrictive diet for life. Untreated HFI patients present an abnormal transferrin (Tf) glycosylation pattern due to the inhibition of mannose-6-phosphate isomerase by fructose-1-phosphate. Hence, elevated serum carbohydrate-deficient Tf (CDT) may allow the prompt detection of HFI. The CDT values improve when an FSS-restrictive diet is followed; however, previous data on CDT and fructose intake correlation are inconsistent. Therefore, we examined the complete serum sialoTf profile and correlated it with FSS dietary intake and with hepatic parameters in a cohort of paediatric and adult fructosemic patients. To do so, the profiles of serum sialoTf from genetically diagnosed HFI patients on an FSS-restricted diet (n = 37) and their age-, sex- and body mass index-paired controls (n = 32) were analysed by capillary zone electrophoresis. We found that in HFI patients, asialoTf correlated with dietary intake of sucrose (R = 0.575, p < 0.001) and FSS (R = 0.475, p = 0.008), and that pentasialoTf+hexasialoTf negatively correlated with dietary intake of fructose (R = -0.386, p = 0.024) and FSS (R = -0.400, p = 0.019). In addition, the tetrasialoTf/disialoTf ratio truthfully differentiated treated HFI patients from healthy controls, with an area under the ROC curve (AUROC) of 0.97, 92% sensitivity, 94% specificity and 93% accuracy.

Chronic systemic exposure to IL6 leads to deregulation of glycolysis and fat accumulation in the zebrafish liver.

Inflammation is a constant in Non-Alcoholic Fatty Liver Disease (NAFLD), although their relationship is unclear. In a transgenic zebrafish system with chronic systemic overexpression of human IL6 (IL6-OE) we show that inflammation can cause intra-hepatic accumulation of triglycerides. Transcriptomics and proteomics analysis of the IL6-OE liver revealed a deregulation of glycolysis/gluconeogenesis pathway, especially a striking down regulation of the glycolytic enzyme aldolase b. Metabolomics analysis by mass spectrometry showed accumulation of hexose monophosphates and their derivatives, which can act as precursors for triglyceride synthesis. Our results suggest that IL6-driven repression of glycolysis/gluconeogenesis, specifically aldolase b, may be a novel mechanism for fatty liver. This mechanism may be relevant for NAFLD in lean individuals, an emerging class of NAFLD prevalent more in Asian Indian populations.

Hereditary Fructose Intolerance Diagnosed in Adulthood.

Hereditary fructose intolerance (HFI) is an autosomal recessive disorder caused by a mutation in the aldolase B gene. HFI patients exhibit nausea, vomiting, abdominal pain, hypoglycemia, and elevated liver enzymes after dietary fructose exposure. Chronic exposure might lead to failure to thrive, liver failure, renal failure, and, eventually, death. HFI usually manifests in infants when they are being weaned off of breastmilk. Because HFI has an excellent prognosis when patients maintain a strict restrictive diet, some patients remain undiagnosed due to the voluntary avoidance of sweet foods. In the past, HFI was diagnosed using a fructose tolerance test, liver enzyme assays or intestinal biopsy specimens. Currently, HFI is diagnosed through the analysis of aldolase B mutations. Here, HFI was diagnosed in a 41-year-old woman who complained of sweating, nausea, and vomiting after consuming sweets. She had a compound heterozygous mutation in the aldolase B gene; gene analysis revealed pathogenic nonsense (c.178C>T, p.Arg60Ter) and frameshift (c.360_363delCAAA, p.Asn120LysfsTer32) variants. This is the first report of a Korean HFI patient diagnosed in adulthood.

Kidney and vascular function in adult patients with hereditary fructose intolerance.

Objective: Previous studies have shown that patients with hereditary fructose intolerance (HFI) are characterized by a greater intrahepatic triglyceride content, despite a fructose-restricted diet. The present study aimed to examine the long-term consequences of HFI on other aldolase-B-expressing organs, i.e. the kidney and vascular endothelium. Methods: Fifteen adult HFI patients were compared to healthy control individuals matched for age, sex and body mass index. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (cf-PWV) and endothelial function by peripheral arterial tonometry, skin laser doppler flowmetry and the endothelial function biomarkers soluble E-selectin [sE-selectin] and von Willebrand factor. Serum creatinine and cystatin C were measured to estimate the glomerular filtration rate (eGFR). Urinary glucose and amino acid excretion and the ratio of tubular maximum reabsorption of phosphate to GFR (TmP/GFR) were determined as measures of proximal tubular function. Results: Median systolic blood pressure was significantly higher in HFI patients (127 versus 122 mmHg, p = .045). Pulse pressure and cf-PWV did not differ between the groups (p = .37 and p = .49, respectively). Of all endothelial function markers, only sE-selectin was significantly higher in HFI patients (p = .004). eGFR was significantly higher in HFI patients than healthy controls (119 versus 104 ml/min/1.73m2, p = .001, respectively). All measurements of proximal tubular function did not differ significantly between the groups. Conclusions: Adult HFI patients treated with a fructose-restricted diet are characterized by a higher sE-selectin level and slightly higher systolic blood pressure, which in time could contribute to a greater cardiovascular risk. The exact cause and, hence, clinical consequences of the higher eGFR in HFI patients, deserves further study.

Aldolase triggers metabolic reprogramming in colorectal cancer in hypoxia and stiff desmoplastic microenvironments.

Colorectal cancer (CRC) progression is highly associated with desmoplasia. Aerobic glycolysis is another distinct feature that appears during the CRC phase of the adenoma-carcinoma sequence. However, the interconnections between the desmoplastic microenvironment and metabolic reprogramming remain largely unexplored. In our in vitro model, we investigated the compounding influences of hypoxia and substrate stiffness, two critical physical features of desmoplasia, on the CRC metabolic shift by using engineered polyacrylamide gels. Unexpectedly, we found that compared to cells on a soft gel (approximately 1.5 kPa, normal tissue), cells on a stiff gel (approximately 8.7 kPa, desmoplastic tissue) exhibited reduced glucose uptake and glycolysis under both normoxia and hypoxia. In addition, the increasing substrate stiffness activated focal adhesion kinase (FAK)/phosphoinositide 3-kinase signaling, but not the mitochondrial respiratory inhibitor HIF-1α. However, the presence of aldolase B (ALDOB) reversed the CRC metabolic response to mechanosignaling; enhanced glucose uptake (approximately 1.5-fold) and aerobic glycolysis (approximately 2- to 3--fold) with significantly decreased mitochondrial oxidative phosphorylation. ALDOB also changed the response of CRC traction force, which is related to tumor metastasis, under hypoxia/normoxia. In summary, our data suggest a counter influence of hypoxia and substrate stiffness on glucose uptake, and ALDOB upregulation can reverse this, which drives hypoxia and stiff substrate to enhance the CRC aerobic glycolysis synergistically. The results not only highlight the potential impacts on metabolic reprogramming led by physical alterations in the microenvironment, but also extend our understanding of the essential role of ALDOB in CRC progression from a biophysical perspective.

Aldolase B impairs DNA mismatch repair and induces apoptosis in colon adenocarcinoma.

Evidence suggests that DNA repair capacity manifested by intact functional base excision repair and mismatch repair (MMR) pathways is related to the prognosis of multiple cancer types. Aldolase B (ALDOB) is well known for its role in metabolism and glycolysis. The expression of ALDOB in colon adenocarcinoma and the relationship between its expression and colon adenocarcinoma prognosis remain controversial; in addition, the potential role of ALDOB in DNA MMR has not yet been reported. In this study, we identified a cluster of DNA repair-related proteins that interact with ALDOB in the colon adenocarcinoma cell line HCT116. Expression analysis of colon adenocarcinoma data from the Cancer Genome Atlas (TCGA-COAD data, n = 551) indicated that ALDOB mRNA expression was significantly higher in specimens with microsatellite instability (MSI) than in specimens with microsatellite stability (MSS). Regarding prognosis, colon adenocarcinoma patients with high ALDOB mRNA expression had longer overall survival (OS). Higher expression of ALDOB protein was significantly correlated with MMR deficiency (d-MMR) in formalin-fixed paraffin-embedded (FFPE) patient specimens. The expression of ALDOB was significantly elevated in colon adenocarcinoma cell lines. Further evidence indicated that rather than affecting proliferation, ALDOB overexpression induced the functional loss of MMR proteins and in turn caused irreversible DNA damage via disrupting EZH2-Rad51 expression and then caused apoptosis by ERK inactivation. Overall, our study demonstrates that high ALDOB expression impairs DNA MMR and induces apoptosis in colon adenocarcinoma. ALDOB may be a new biomarker associated with d-MMR and an independent prognostic factor for colon adenocarcinoma.

Daily Fructose Traces Intake and Liver Injury in Children with Hereditary Fructose Intolerance.

BACKGROUND: Hereditary fructose intolerance (HFI) is a rare genetic disorder of fructose metabolism due to aldolase B enzyme deficiency. Treatment consists of fructose, sorbitol, and sucrose (FSS)-free diet. We explore possible correlations between daily fructose traces intake and liver injury biomarkers on a long-term period, in a cohort of young patients affected by HFI. METHODS: Patients' clinical data and fructose daily intake were retrospectively collected. Correlations among fructose intake, serum alanine aminotransferase (ALT) level, carbohydrate-deficient transferrin (CDT) percentage, liver ultrasonography, genotype were analyzed. RESULTS: We included 48 patients whose mean follow-up was 10.3 ± 5.6 years and fructose intake 169 ± 145.4 mg/day. Eighteen patients had persistently high ALT level, nine had abnormal CDT profile, 45 had signs of liver steatosis. Fructose intake did not correlate with ALT level nor with steatosis severity, whereas it correlated with disialotransferrin percentage (R2 0.7, p < 0.0001) and tetrasialotransferrin/disialotransferrin ratio (R2 0.5, p = 0.0001). p.A150P homozygous patients had lower ALT values at diagnosis than p.A175D variant homozygotes cases (58 ± 55 IU/L vs. 143 ± 90 IU/L, p = 0.01). CONCLUSION: A group of HFI patients on FSS-free diet presented persistent mild hypertransaminasemia which did not correlate with fructose intake. Genotypes may influence serum liver enzyme levels. CDT profile represents a good marker to assess FSS intake.

Gluconeogenic Enzymes in ß-Cells: Pharmacological Targets for Improving Insulin Secretion.

Pancreatic ß-cells express the gluconeogenic enzymes glucose 6-phosphatase (G6Pase), fructose 1,6-bisphosphatase (FBP), and phosphoenolpyruvate (PEP) carboxykinase (PCK), which modulate glucose-stimulated insulin secretion (GSIS) through their ability to reverse otherwise irreversible glycolytic steps. Here, we review current knowledge about the expression and regulation of these enzymes in the context of manipulating them to improve insulin secretion in diabetics. Because the regulation of gluconeogenic enzymes in ß-cells is so poorly understood, we propose novel research avenues to study these enzymes as modulators of insulin secretion and ß-cell dysfunction, with especial attention to FBP, which constitutes an attractive target with an inhibitor under clinical evaluation at present.

Fructosuria and recurrent hypoglycemia in a patient with a novel c.1693T>A variant in the 3' untranslated region of the aldolase B gene.

Hereditary fructose intolerance, caused by mutations in the ALDOB gene, is an unusual cause of hypoglycemia. ALDOB encodes the enzyme aldolase B, responsible for the hydrolysis of fructose 1-phosphate in the liver. Here, we report the case of a 33-year-old female patient who consulted due to repetitive episodes of weakness, dizziness and headache after food ingestion. An ambulatory 72-h continuous glucose monitoring revealed multiple short hypoglycemic episodes over the day. After biochemical exclusion of other endocrine causes of hypoglycemia, hereditary fructose intolerance seemed a plausible diagnosis. Repeated measurements of urinary fructose revealed pathologic fructosuria, but genetic testing for the three most common mutations in ALDOB resulted negative. We decided to perform complete Sanger sequencing of the ALDOB gene and encountered a variant consisting of a T>A substitution in position 1963 of the ALDOB transcript (c.1693T>A). This position is located within the 3' untranslated region of exon 9, 515 nucleotides downstream the stop codon. After complete withdrawal of dietary fructose and sucrose, the patient presented no new hypoglycemic episodes.

Aldolase B-Mediated Fructose Metabolism Drives Metabolic Reprogramming of Colon Cancer Liver Metastasis.

Cancer metastasis accounts for the majority of cancer-related deaths and remains a clinical challenge. Metastatic cancer cells generally resemble cells of the primary cancer, but they may be influenced by the milieu of the organs they colonize. Here, we show that colorectal cancer cells undergo metabolic reprogramming after they metastasize and colonize the liver, a key metabolic organ. In particular, via GATA6, metastatic cells in the liver upregulate the enzyme aldolase B (ALDOB), which enhances fructose metabolism and provides fuel for major pathways of central carbon metabolism during tumor cell proliferation. Targeting ALDOB or reducing dietary fructose significantly reduces liver metastatic growth but has little effect on the primary tumor. Our findings suggest that metastatic cells can take advantage of reprogrammed metabolism in their new microenvironment, especially in a metabolically active organ such as the liver. Manipulation of involved pathways may affect the course of metastatic growth.

Functions of the Heterologous Intron-Derived Fragments Intra and Extra Factor IX-cDNA Coding Region on the Human Factor IX Expression in HepG2 and Hek-293T Cells.

BACKGROUND: Human FIX (hFIX) gene transfer into hepatocytes has provided a novel approach for treatment of hemophilia B. To obtain an improved expression of hFIX, the functional hFIX-expressing plasmids with appropriate intron-derived fragments which facilitate transcription and promote an efficient 3'-end formation of mRNAs are required. OBJECTIVES: We aim to evaluate the functions of the heterologous intron-derived fragments intra and extra hFIX-cDNA coding region with respect to the hFIX expression in the hepatocytes and kidney cells. MATERIALS AND METHODS: HepG2 cells as differentiated hepatocytes and Hek-293T cells as embryonic kidney cells were transfected with the different hFIX-expressing plasmids containing various combinations of the two human beta-globin (hBG) introns within the hFIX-cDNA and Kozak sequence. In the next stage, as a hepatocyte-specific sequence, the rat aldolase B intronic enhancer sequence (rABE), was isolated from the first intron of the rat aldoase B gene and inserted within the upstream CMV promoter (CMVp) and efficacies of the engineered vectors were investigated in the stably-transfected HepG2 cells. RESULTS: Our data indicate that the intron-less construct and hBG intron-I containing construct are more effective with regard to hFIX expression compared to other constructs in Hek-293 cells. In HepG2 cells, the rABE in combination with CMVp in context of intron-less plasmid induced an increase in total expression of hFIX protein dramatically; ranging from 2.3 to 40 folds increase compared to other constructs. The rABE in combination with CMVp in the hBG intron-I, hBG intron-II, and hBG intron-I,II containing plasmids induced 3.7, 2, and 1.6-fold increase in the total expression of hFIX protein, respectively. The presence of both hBG intronic sequences within the hFIX-cDNA induced a higher secretion level of hFIX than either intron-I or II alone and provided correctly spliced hFIX transcripts in HepG2 and kidney cell lines. The intron-less construct with or without rABE induced the highest hFIX mRNA levels in HepG2 and Hek-293T cells respectively compared to other constructs. CONCLUSIONS: The embryonic kidney cells in addition to the differentiated hepatic cell lines could be successfully targeted by plasmid vectors. The intron-less and hBG intron-I containing plasmids represent a particular interest in producing recombinant hFIX in Hek-293T cells. The synergistic function on the hFIX expression that was achieved by combining the CMVp with the liver-specific rABE would be a useful approach for future designing of the expression cassettes for hepatocyte-mediated gene expression in hemophilia B.

High Expression of Aldolase B Confers a Poor Prognosis for Rectal Cancer Patients Receiving Neoadjuvant Chemoradiotherapy.

Background : Colorectal cancer is the third most common cancer in both sex worldwide and it is also the fourth most common cause of cancer mortality. For rectal cancer, neoadjuvant concurrent chemoradiotherapy (CCRT) followed by radical proctectomy is gold standard treatment for patients with stage II/III rectal cancer. By data mining a documented database of rectal cancer transcriptome (GSE35452) from Gene Expression Omnibus, National Center of Biotechnology Information, we recognized that ALDOB was the most significantly up-regulated transcript among those related to glycolysis (GO: 0006096). Hence, we analyzed the clinicopathological correlation and prognostic effect of ALDOB protein (Aldolase B), which encoded by ALDOB gene. Methods : ALDOB immunostain was performed in 172 rectal adenocarcinomas treated with preoperative chemoradiotherapy followed by radical surgery, which were divided into high- and low-expression groups. Furthermore, statistical analyses were examined to correlate the relationship between ALDOB immunoreactivity and important clinical and pathological characteristics, as well as three survival indices: disease-specific survival (DSS), local recurrence-free survival (LRFS) and metastasis-free survival (MeFS). Results : ALDOB (Aldolase B) over-expression was significantly associated with pre-CCRT and post-CCRT tumor advancement, lymphovascular invasion, perineural invasion and poor response to CCRT (all P ≤ .023). In addition, ALDOB high expression was linked to adverse DSS, LRFS and MeFS in univariate analysis (P ≤ .0075) and also served as an independent prognosticator indicating dismal DSS and MeFS in multivariate analysis (hazard ratio (HR) = 3.462, 95% confidence interval (CI): 1.263-9.495; HR = 2.846, 95% CI: 1.190-6.808, respectively). Conclusion : ALDOB (Aldolase B) may play an imperative role in rectal cancer progression and responsiveness to neoadjuvant CCRT, and serve as a novel prognostic biomarker. Additional researches to clarify the molecular and biochemical pathways are essential for developing promising ALDOB-targeted therapies for patients with rectal cancers.