Clinical improvement may not reflect metabolic homeostasis normalization in subjects with and without Roux-En-Y bariatric surgery after 12 years: comparison of surgical subjects to a lean cohort.

Background: A 12-year study comparing clinical outcomes following Roux-en-Y bariatric surgery showed long-term weight loss with remission/prevention of type-2-diabetes (T2D), hypertension and dyslipidemia. However, it is unknown whether the underlying homeostatic metabolic processes involving hepatokines, adipokines and myokines also normalize. Using this 12-year study, we determined whether metabolic indices improved in post-surgical (BMI:34.4kg/m2) versus non-surgical comparator-subjects-with-obesity (BMI:43.8kg/m2) at 12-year follow-up (both cohorts with baseline diabetes), and if post-surgical subjects normalized their metabolic processes to those of a normal-weight cohort without diabetes. Methods: Cross-sectional design. Plasma from a cohort of Roux-en-Y bariatric surgery (n=50) and non-surgery (n=76) comparator-subjects-with-obesity (both cohorts at 12-year follow-up) plus a normal-weight cohort (n=39) was assayed by Luminex immunoassay or ELISA for hepatokines [angiopoietin-like proteins-(ANGPTL3; ANGPTL4; ANGPTL6); fibroblast growth factors-(FGF19; FGF21; FGF23)]; adipokines [adipsin; adiponectin; FGF19] and myonectin. Results: After age and gender adjustment, surgery versus comparator-subjects-with-obesity had lower BMI (34.4 ± 1.0 vs 43.8 ± 0.9kg/m2; p<0.0001), HbA1c (6.2 ± 0.3 vs 7.7 ± 0.2%; p<0.0001), insulin resistance (HOMA-IR, 2.0 ± 1.5 vs 10.8 ± 1.4; p<0.0001) fat mass (45.6 ± 2.2 vs 60.0 ± 2.0; p<0.0001), HDL-C (55.4 ± 2.6 vs 42.6 ± 2.3mg/dL; p<0.0001), triglycerides (130 ± 14 vs 187 ± 12mg/dL; p<0.0001) and higher adiponectin (25.9 ± 2.3 vs 15.7 ± 2.0µg/ml; p<0.001); Adipsin, ANGPTL3, ANGPTL4, ANGPTL6, FGF19, FGF21, FGF23 and myonectin did not differ. Surgery versus normal-weight group: higher ANGPTL4 (156 ± 6 vs 119 ± 7ng/mL; p<0.0001), higher FGF23 (96.4 ± 10.1 vs 50.9 ± 11.5pg/mL; p=0.007) and lower myonectin (744 ± 55 vs 969 ± 66ng/mL; p=0.002); adiponectin, adipsin ANGPTL3, ANGPTL6, FGF19, FGF21 did not differ. Non-surgery comparator-subjects-with-obesity versus normal-weight group: higher adipsin (1859 ± 94 vs 1314 ± 133ng/mL; p=0.0001), higher FGF23 (84.6 ± 8.5 vs 50.9 ± 11.5pg/mL; p<0.0001) and higher ANGPTL4 (171 ± 5 vs 119 ± 7ng/mL; p<0.0001); adiponectin ANGPTL3, ANGPTL6, FGF19, FGF21 and myonectin did not differ. Conclusion: Bariatric surgery markedly improved anthropometric and metabolic features versus comparator-subjects-with-obesity at 12-year follow-up, indicating benefit of weight loss. However, despite weight loss, these patients still had class-1 obesity, as reflected in the adipokine, hepatokine and myokine markers of body homeostasis that did not completely normalize to indicative values of normal-weight subjects, suggesting either that this is the new normal for these patients or that weight loss to a BMI<25kg/m2 is needed for normalization of these parameters.

Associations of ANGPTL6, DOCK6, FABP1, and PCSK9 single-nucleotide variants with hypercholesterolemia in the Polish population: a cross-sectional study.

INTRODUCTION: Hypercholesterolemia is a chronic noncommunicable disease predisposing to cardiovascular diseases. Genome­wide association studies have shown that more than 500 common nucleotide variants are associated with dyslipidemia. OBJECTIVES: We evaluated associations between selected nucleotide variants in ANGPTL6, DOCK6, FABP1, and PCSK9 genes and hypercholesterolemia in the Polish adult population sample. PATIENTS AND METHODS: The study included 109 patients with hypercholesterolemia and 251 individuals with no diagnosed lipid disorder. Genotyping of ANGPTL6 rs8112063, DOCK6 rs737337 and rs17699089, FABP1 rs2241883 and rs2919872, and PCSK9 rs562556 and rs11206510 was carried out using highresolution melting curve analysis. Serum concentrations of FABP1, PCSK9, ANGPTL6, and ANGPTL8 were determined in 51 individuals by enzyme­linked immunosorbent assay. RESULTS: Carriers of the FABP1 rs2919872 CC genotype were over 2.5­fold less likely to be diagnosed with hypercholesterolemia than carriers of the T allele (odds ratio [OR], 0.386; 95% CI, 0.203-0.735; P = 0.003; Pcorr = 0.006). There were no associations between rs2919872 and serum lipid concentrations. Carriers of the ANGPTL6 rs8112063 C allele had an almost 2­fold higher risk of developing hypercholesterolemia than carriers of the T allele (OR, 1.820; 95% CI, 1.053-3.144; P = 0.03; Pcorr = 0.046). Moreover, the carriers of the ANGPTL6 rs8112063 C allele had higher serum concentrations of high-density lipoprotein cholesterol than those with TT genotype (P = 0.009). There were no significant associations between the other tested variants and hypercholesterolemia. CONCLUSIONS: FABP1 rs2919872 and ANGPTL6 rs8112063 are associated with a risk of hypercholesterolemia in the Polish population.

Use of proteomics to identify mechanisms of hepatocellular carcinoma with the CYP2D6*10 polymorphism and identification of ANGPTL6 as a new diagnostic and prognostic biomarker.

BACKGROUND: Although an association between the cytochrome P4502D6 (CYP2D6) *10 (100C>T) polymorphism and hepatocellular carcinoma (HCC) is known, the mechanism remains unclear. Here we aimed to explore mechanisms of CYP2D6*10 (100C>T) polymorphism conferring to HCC, and screen markers for HCC. METHODS: Label-free global proteome profiling with 34 normal livers and peritumor tissue from 61 HCC patients was performed, and angiopoietin-like protein-6 (ANGPTL6) was evaluated in 2 liver samples validation cohorts and 2 blood specimens validation cohorts. RESULTS: We found a significantly decreased frequency of TT in HCC patients which reduced HCC susceptibility by 69.2% and was accompanied by lowered enzymatic activity for CYP2D6. Proteomic analysis revealed 1342 differentially expressed proteins (DEPs) that were associated with HCC and 88 DEPs were identified as 100 TT-related proteins, likely underlying the susceptibility to HCC. Twenty-two upregulated DEPs and 66 downregulated DEPs were mainly related to lipid metabolism and the extracellular matrix, respectively. High ANGPTL6 was associated with a higher risk to HCC and worse prognosis. ANGPTL6 was both an independent risk factor and an independent prognostic factor for HCC and exhibited strong potential for predicting HCC occurrence, with comparable AUC values and higher sensitivity compared with alpha-fetoprotein. CONCLUSIONS: The TT genotype-associated decreased risk of HCC appears to be related to lowered CYP2D6 activity and altered protein expression in the tumor microenvironment, and ANGPTL6 is a promising new diagnostic and prognostic biomarker for HCC. Our findings reveal new mechanistic insights for polymorphisms related to HCC risk and provide avenues for screening for HCC.

Effects of Bariatric Surgeries on Fetuin-A, Selenoprotein P, Angiopoietin-Like Protein 6, and Fibroblast Growth Factor 21 Concentration.

Obesity is a civilization disease representing a global health problem. Excessive body weight significantly reduces the quality of life. It is also associated with the leading causes of death, including type 2 diabetes mellitus, cardiovascular diseases, and numerous types of cancer. The mainstay of therapy is a dietary treatment. However, in morbidly obese patients, dietary treatment is often insufficient. In these patients, the most effective procedure is bariatric surgery, but it is still difficult to predict its outcome and metabolic changes. Hepatokines are proteins secreted by hepatocytes. Many of them, including fetuin-A, selenoprotein P, angiopoietin-like protein 6, and fibroblast growth factor 21, have been linked to metabolic dysfunctions. In this context, hepatokines may prove helpful. This review investigates the possible changes in hepatokine profiles after selected bariatric surgery protocols. In this regard, Roux-en-Y gastric bypass is the most studied type of surgery. The overall analysis of published research identified fetuin-A as a potential marker of metabolic alternations in patients after bariatric surgery.

Mining the role of angiopoietin-like protein family in gastric cancer and seeking potential therapeutic targets by integrative bioinformatics analysis.

BACKGROUND: The indistinctive effects of antiangiogenesis agents in gastric cancer (GC) can be attributed to multifaceted gene dysregulation associated with angiogenesis. Angiopoietin-like (ANGPTL) proteins are secreted proteins regulating angiogenesis. They are also involved in inflammation and metabolism. Emerging evidences have revealed their various roles in carcinogenesis and metastasis development. However, the mRNA expression profiles, prognostic values, and biological functions of ANGPTL proteins in GC are still elucidated. METHODS: We compared the transcriptional expression levels of ANGPTL proteins between GC and normal gastric tissues using ONCOMINE and TCGA-STAD. The prognostic values were evaluated by LinkedOmics and Kaplan-Meier Plotter, while the association of expression levels with clinicopathological features was generated through cBioPortal. We conducted the functional enrichment analysis with Metascape. RESULTS: The expression of ANGPTL1/3/6 was lower in GC tissues than in normal gastric tissues. High expression of ANGPTL1/2/4 was correlated with short overall survival and post-progression survival in GC patients. Upregulated ANGPTL1/2 was correlated with higher histological grade, non-intestinal Lauren classification, and advanced T stage, while ANGPTL4 exhibited high expression in early T stage, M1 stage, and non-intestinal Lauren classification. CONCLUSIONS: Integrative bioinformatics analysis suggests that ANGPTL1/2/4 may be potential therapeutic targets in GC patients. Among them, ANGPTL2 acts as a GC promoter, while ANGPTL1/4's role in GC is still uncertain.

Exome sequencing in 38 patients with intracranial aneurysms and subarachnoid hemorrhage.

OBJECTIVE: Genetic risk factors for unruptured intracranial aneurysms (UIA) and aneurysmal subarachnoid hemorrhage (aSAH) are poorly understood. We aimed to verify recently reported risk genes and to identify novel sequence variants involved in the etiology of UIA/aSAH. METHODS: We performed exome sequencing (ES) in 35 unrelated individuals and 3 family members, each with a history of UIA and/or aSAH. We searched for sequence variants with minor allele frequency (MAF) ≤ 5% in the reported risk genes ADAMTS15, ANGPTL6, ARHGEF17, LOXL2, PCNT, RNF213, THSD1 and TMEM132B. To identify novel putative risk genes we looked for unknown (MAF = 0) variants shared by the three relatives. RESULTS: We identified 20 variants with MAF ≤ 5% in 18 individuals: 9 variants in PCNT (9 patients), 4 in RNF213 (3 patients), 3 in THSD1 (6 patients), 2 in ANGPTL6 (3 patients), 1 in ADAMTS15 (1 patient) and 1 in TMEM132B (1 patient). In the affected family, prioritization of shared sequence variants yielded five novel putative risk genes. Based on predicted pathogenicity of identified variants, population genetics data and a high functional relevance for vascular biology, EDIL3 was selected as top candidate and screened in additional 37 individuals with UIA and/or aSAH: a further very rare EDIL3 sequence variant in two unrelated sporadic patients was identified. CONCLUSIONS: Our data support a role of sequence variants in PCNT, RNF213 and THSD1 as susceptibility factors for cerebrovascular disease. The documented function in vascular wall integrity, the crucial localization of affected amino acids and gene/variant association tests suggest EDIL3 as a further valid candidate disease gene for UIA/aSAH.

Serum Angiopoietin-like Protein 6, Risk of Type 2 Diabetes, and Response to Hyperglycemia: A Prospective Cohort Study.

CONTEXT: Angiopoietin-like protein 6 (ANGPTL6) is a hepatokine that improves insulin sensitivity in animals. However, serum ANGPTL6 concentration was found to be higher in human participants with diabetes or metabolic syndrome in cross-sectional studies, implying that ANGPTL6 may be induced to counteract hyperglycemia. OBJECTIVE: To investigate whether serum ANGPTL6 can predict incident diabetes and explore whether glucose or insulin can regulate ANGPTL6 expression and secretion. DESIGN: This cohort study included adults without diabetes at baseline who were followed every 2 years for incident diabetes. Serum ANGPTL6 concentrations were measured at baseline and during oral glucose tolerance tests (OGTTs). A hepatic cell line, HepG2, and diet-induced obesity mouse model were used to evaluate the response of ANGPTL6 expression and secretion to hyperglycemia and the metabolic syndrome. RESULTS: We recruited 1103 participants without diabetes at baseline. During the 4.22-year follow-up, 113 (10.2%) participants developed incident diabetes. Serum ANGPTL6 was negatively associated with the incidence of diabetes (adjusted hazard ratio, 0.77; P = 0.042). However, serum ANGPTL6 level was higher in participants with prediabetes (P = 0.018) and was elevated during OGTT. In HepG2 cells, treatment with glucose, but not insulin, induced ANGPTL6 expression. Hepatic ANGPTL6 expression and serum ANGPTL6 concentrations were significantly higher in mice fed with a high-fat diet than in those fed with a standard chow (both P < 0.05). CONCLUSION: A high serum ANGPTL6 level is associated with a low incidence of diabetes in humans. ANGPTL6 is expressed and secreted in response to hyperglycemia to maintain glucose homeostasis.

The association between dietary antioxidants and adipokines level among obese women.

AIM: Adipokines are associated with several oxidative stress-related diseases and pathologic conditions. We aimed to assess the association between antioxidants and adipokines in obese adults. METHODS AND MATERIALS: In this cross-sectional study, a total of 160 obese women were included. Body composition and anthropometric characteristics were measured. Dietary intakes were assessed by 3-day, 24-h dietary recall. Blood samples were obtained following an overnight fasting. Serum concentrations of adipokines including progranulin, retinol binding protein 4 (RBP4) and Angiopoietin-related growth factor 6 (ANGPTL6) was measured using an enzyme-linked immunosorbent assay. ANCOVA and the linear regression model analysis was performed to assess the relationship between Progranulin, RBP4, AnGPTL6, and antioxidants. RESULTS: Mean age of included women was 39.31 ±â€¯12.10. Mean and standard deviation for BMI was 35.05 ±â€¯4.26 in this obese population. There was a positive significant association between ANGPTL6 and vitamin D intake (p < 0.001). Also, there was a marginal association between RBP4 and vitamin A (p = 0.063) intake, but after adjustment age, and fat mass, we found a significant association (p = 0.008). However, the associations between dietary antioxidants, progranulin, and ANGPTL6 were not statistically significant. CONCLUSIONS: ANGPTL6 and RBP4 levels directly associated with dietary vitamins D and A intake, respectively. But, according to the results, the association between ANGPTL6 and vitamin D was bidirectional. The suggested associations probably can be useful in the development of interventional studies for management of chronic diseases.

ANGPTL6-mediated angiogenesis promotes alpha fetoprotein-producing gastric cancer progression.

Alpha-fetoprotein (AFP)-producing gastric cancer (AFPGC) is regarded as a rare but highly malignant gastric adenocarcinoma subtype and its clinic pathological presentation mimics hepatocellular carcinoma. However, the underlying mechanism of this disease remains elusive. The level of ANGPTL6 in AFPGC cell lines is much higher than that of common types of gastric cancer cells. A high level of ANGPTL6 confers a poor prognosis and is correlated with the expression of CD34 (an endothelial cell marker). ANGPTL6 promotes endothelial cell migration and tube formation, Moreover, ANGPTL6 knockdown inhibits cancer cell apoptosis and invasiveness. Mechanistically, ANGPTL6 activates the ERK1/2 and AKT pathways. Treatment of ERK1/2 or AKT inhibitor can attenuated cell migration and tube formation. ANGPTL6 loss results in tumor growth in vivo. Our study revealed that ANGPTL6 is an important driver gene of angiogenesis in AFPGC development. These findings provide not only an effective biomarker for diagnosis but also an attractive therapeutic target for use in AFPGC patients.

Angiopoietin-like protein 6 in patients with obesity, type 2 diabetes mellitus, and anorexia nervosa: The influence of very low-calorie diet, bariatric surgery, and partial realimentation.

AIM OF THE STUDY: Angiopoietin-like protein 6 (ANGPTL6) is a circulating protein with a potential role in energy homeostasis. The aim of the study was to explore the changes in ANGPTL6 levels in patients with obesity (Body mass index, BMI > 40 kg/m2) with and without type 2 diabetes mellitus (T2DM) undergoing dietary intervention (very low calorie diet - VLCD) and in a subgroup of T2DM patients after bariatric surgery. Additionally, we examined changes in ANGPTL6 in anorexia nervosa (AN) patients at baseline and after partial realimentation. We also explored the changes in ANGPTL6 mRNA expression in subcutaneous adipose tissue (SAT) of obese subjects. MATERIALS AND METHODS: The study included 23 non-diabetic obese patients, 40 obese patients with T2DM (27 underwent VLCD and 13 underwent bariatric surgery), 22 patients with AN, and 37 healthy control subjects. RESULTS: ANGPTL6 levels of AN patients were increased relative to the control group (68.6 ± 9.9 ng/ml) and decreased from 110.2 ± 13.3 to 73.6 ± 7.1 ng/ml (p = 0.004) after partial realimentation. Baseline ANGPTL6 levels in patients with obesity and T2DM did not differ from the control group. VLCD decreased ANGPTL6 levels only in obese patients with T2DM. Bariatric surgery induced a transient elevation of ANGPTL6 levels with a subsequent decrease to baseline levels. ANGPTL6 mRNA expression transiently increased after bariatric surgery and returned to baseline levels after 12 months. CONCLUSIONS: Collectively, our data suggest that serum ANGPTL6 levels and ANGPTL6 mRNA expression in SAT are affected by metabolic disorders and their treatment but do not appear to directly reflect nutritional status.

Upregulation of ANGPTL6 in mouse keratinocytes enhances susceptibility to psoriasis.

Psoriasis is a chronic inflammatory skin disease marked by aberrant tissue repair. Mutant mice modeling psoriasis skin characteristics have provided useful information relevant to molecular mechanisms and could serve to evaluate therapeutic strategies. Here, we found that epidermal ANGPTL6 expression was markedly induced during tissue repair in mice. Analysis of mice overexpressing ANGPTL6 in keratinocytes (K14-Angptl6 Tg mice) revealed that epidermal ANGPTL6 activity promotes aberrant epidermal barrier function due to hyperproliferation of prematurely differentiated keratinocytes. Moreover, skin tissues of K14-Angptl6 Tg mice showed aberrantly activated skin tissue inflammation seen in psoriasis. Levels of the proteins S100A9, recently proposed as therapeutic targets for psoriasis, also increased in skin tissue of K14-Angptl6 Tg mice, but psoriasis-like inflammatory phenotypes in those mice were not rescued by S100A9 deletion. This finding suggests that decreasing S100A9 levels may not ameliorate all cases of psoriasis and that diverse mechanisms underlie the condition. Finally, we observed enhanced levels of epidermal ANGPTL6 in tissue specimens from some psoriasis patients. We conclude that the K14-Angptl6 Tg mouse is useful to investigate psoriasis pathogenesis and for preclinical testing of new therapeutics. Our study also suggests that ANGPTL6 activation in keratinocytes enhances psoriasis susceptibility.

AGK-BRAF gene fusion is a recurrent event in sporadic pediatric thyroid carcinoma.

Thyroid cancer is the fastest increasing cancer worldwide in all age groups. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer in both adults and children. PTC genomic landscape has been extensively studied in adults, but information regarding sporadic pediatric patients is lacking. Although BRAF V600E mutation is highly prevalent in adults, this mutation is uncommon in pediatric cases. As adult and pediatric PTC is a mitogen-activated protein kinase-driven cancer, this altered pathway might be activated by different genetic events. The aim of this study was to investigate the occurrence of AGK-BRAF fusion gene, recently described in radiation-exposed pediatric PTC, in a cohort of exclusively sporadic pediatric PTC. The series consisted of 30 pediatric PTC younger than 18 years of age at the time of diagnosis and 15 matched lymph node metastases (LNM). Primary tumors and matched LNM were screened for the presence of the AGK-BRAF fusion transcript by RT-PCR. To confirm the identity of the amplified products, randomly selected samples positive for the presence of the fusion transcripts were sequenced. Moreover, BRAF dual-color, break-apart probes confirmed BRAF rearrangement. Overall, the AGK-BRAF fusion gene was detected in 10% (3/30) of primary tumors. For one of these cases, paired LNM was also available, which also shows the presence of AGK-BRAF fusion gene. This study described, for the first time, the presence of AGK-BRAF in sporadic pediatric PTC. Understanding the molecular events underlying pediatric PTC may improve preoperative diagnosis, allow molecular prognostication and define a therapeutic approach toward sporadic PTC patients.

Longitudinal Changes in Serum Levels of Angiopoietin-Like Protein 6 and Selenoprotein P After Gastric Bypass Surgery.

BACKGROUND: Bariatric surgery has beneficial effects on weight loss and metabolic profiles. Recent evidence suggests that liver-derived hepatokines play a role in the pathophysiology of metabolic diseases. However, few studies have reported longitudinal changes in hepatokines after gastric bypass surgery. We investigated changes in the serum levels of angiopoietin-like protein 6 (Angptl6) and selenoprotein P after gastric bypass surgery. METHODS: We followed 10 patients who were treated with gastric bypass for weight loss. We measured metabolic parameters and the serum levels of Angptl6 and selenoprotein P before, 1 month after, and 9 months after surgery. We investigated the changes in those hepatokines after surgery and the associations between changes in Angptl6 and selenoprotein P, respectively, and metabolic parameters. RESULTS: Body mass index decreased linearly. Levels of hemoglobin A1c (HbA1c), aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (GGT), total cholesterol, triglyceride, LDL cholesterol, and Angptl6 were significantly lower 1 and 9 months after surgery. Fasting plasma glucose was normal throughout the study. Fasting insulin decreased 1 month after surgery but increased 9 months post-surgery. Levels of selenoprotein P increased linearly. Significant correlations were detected between the levels of Angptl6 and LDL cholesterol and fasting insulin. Changes in Angptl6 levels were significantly correlated with changes in total cholesterol and LDL cholesterol. Selenoprotein P levels were inversely correlated with GGT, and changes in selenoprotein P were inversely correlated with changes in homeostasis model assessment for insulin resistance (HOMA-IR). CONCLUSIONS: Our results suggest that gastric bypass may alter the serum levels of hepatokines independent of weight loss, and these changes are related to certain hepatic metabolic changes.

Dynamic roles of angiopoietin-like proteins 1, 2, 3, 4, 6 and 7 in the survival and enhancement of ex vivo expansion of bone-marrow hematopoietic stem cells.

Recent advances in hematopoietic stem cells (HSCs) expansion by growth factors including angiopoietin-like proteins (Angptls) have opened up the possibility to use HSCs in regenerative medicine. However, the unavailability of true in vitro HSCs expansion by these growth factors has limited the understanding of the cellular and molecular mechanism of HSCs expansion. Here, we report the functional role of mouse Angptls 1, 2, 3, 4, 6 and 7 and growth factors SCF, TPO, IGF-2 and FGF-1 on purified mouse bone-marrow (BM) Lineage(-)Sca-1(+)(Lin-Sca-1(+)) HSCs. The recombinant retroviral transduced-CHO-S cells that secrete Angptls in serum-free medium were used alone or in combination with growth factors (SCF, TPO, IGF-2 and FGF-1). None of the Angptls stimulated HSC proliferation, enhanced or inhibited HSCs colony formation, but they did support the survival of HSCs. By contrast, any of the six Angptls together with saturating levels of growth factors dramatically stimulated a 3- to 4.5-fold net expansion of HSCs compared to stimulation with a combination of those growth factors alone. These findings lead to an understanding of the basic function of Angptls on signaling pathways for the survival as well as expansion of HSCs in the bone marrow niche.

A complex of α6 integrin and E-cadherin drives liver metastasis of colorectal cancer cells through hepatic angiopoietin-like 6.

Homing of colorectal cancer (CRC) cells to the liver is a non-random process driven by a crosstalk between tumour cells and components of the host tissue. Here we report the isolation of a liver metastasis-specific peptide ligand (CGIYRLRSC) that binds a complex of E-cadherin and α(6) integrin on the surface of CRC cells. We identify angiopoietin-like 6 protein as a peptide-mimicked natural ligand enriched in hepatic blood vessels of CRC patients. We demonstrate that an interaction between hepatic angiopoietin-like 6 and tumoural α(6) integrin/E-cadherin drives liver homing and colonization by CRC cells, and that CGIYRLRSC inhibits liver metastasis through interference with this ligand/receptor system. Our results indicate a mechanism for metastasis whereby a soluble factor accumulated in normal vessels functions as a specific ligand for circulating cancer cells. Consistently, we show that high amounts of coexpressed α(6) integrin and E-cadherin in primary tumours represent a poor prognostic factor for patients with advanced CRC.

Serum levels of angiopoietin-related growth factor (AGF) are increased in polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a frequent reproductive and metabolic disorder associated with insulin resistance. Recently, angiopoietins were identified in the systemic circulation and have been designated angiopoietinlike proteins (ANGPTL). More recently, it is shown that angiopoietin-related growth factor (AGF, also called ANGPTL6) directly regulate lipid, glucose, and energy metabolism independent of angiogenic effects in animal studies. The aim of this study was to determine whether there is an association between AGF and PCOS. METHODS: The study included 55 [corrected] patients with PCOS and 30 healthy control women. We analyzed serum levels of AGF and other biochemical and anthropometric markers in all the subjects. RESULTS: This study showed that serum AGF levels were significantly higher in the subjects with PCOS (102.28 ng/mL) than those in the healthy control group (63.08 ng/mL; P < 0.001). Body mass index (24.33 vs 22.11 kg/m; P = 0.017), free testosterone (2.81 vs 2.17 pmol/L; P = 0.009), androstenedione (3.28 vs 2.92 nmol/L; P = 0.033), 17-hydroxyprogesterone (2.72 vs 2.09 ng/mL; P = 0.039), homeostasis model of assessment-insulin resistance (2.65 vs 1.9; P = 0.016), and fasting glucose (107.09 vs 96.18 mmol/L; P = 0.001) were found significantly higher in PCOS group than in control group. But there was no correlation between AGF and these parameters in PCOS group. In addition, no correlation between the AGF and other distinctive features of PCOS was found. CONCLUSIONS: Serum AGF levels were paradoxically increased in patients with PCOS in comparison with data of animal experiments. Further studies are needed to better elucidate the physiologic significance of circulating AGF in human disease.

Serum angiopoietin-related growth factor (AGF) levels are elevated in gestational diabetes mellitus and associated with insulin resistance.

OBJECTIVE: Angiopoietin-related growth factor (AGF) is associated with angiogenesis but it can also affect glucose and energy metabolism. The aim of the study was to determine AGF levels in gestational diabetes mellitus (GDM). MATERIALS AND METHODS: The study included 44 patients with GDM (GDM group) and 33 non-diabetic, healthy women in the third trimester of pregnancy (control group). We analyzed serum levels of AGF and other biochemical and anthropometric markers in all subjects. RESULTS: The study revealed that serum AGF levels were significantly higher in patients with GDM (113.30 +/- 69.92 ng/ml) than in controls (52.30 +/- 35.59 ng/ml), (p-value<0.001). Fasting glucose (117.59 vs. 82.18), homeostasis model of assessment - insulin resistance (HOMA-IR), (2.91 vs. 1.75) diastolic (74.20 vs. 70.00) and mean (89.09 vs. 84.84) blood pressure were found to be significantly higher in the GDM group when compared to the control group (p-value<0.05). There was a significant positive association between AGF and HOMA-IR in the GDM group. CONCLUSIONS: Although gestational diabetes mellitus can be a predictor of serum AGF level, further studies are needed to explain the physiologic roles of AGF in glucose metabolism.

KRAS(G12V) enhances proliferation and initiates myelomonocytic differentiation in human stem/progenitor cells via intrinsic and extrinsic pathways.

In human hematopoietic malignancies, RAS mutations are frequently observed. Yet, little is known about signal transduction pathways that mediate KRAS-induced phenotypes in human CD34(+) stem/progenitor cells. When cultured on bone marrow stroma, we observed that KRAS(G12V)-transduced cord blood (CB) CD34(+) cells displayed a strong proliferative advantage over control cells, which coincided with increased early cobblestone (CAFC) formation and induction of myelomonocytic differentiation. However, the KRAS(G12V)-induced proliferative advantage was transient. By week three no progenitors remained in KRAS(G12V)-transduced cultures and cells were all terminally differentiated into monocytes/macrophages. In line with these results, LTC-IC frequencies were strongly reduced. Both the ERK and p38 MAPK pathways, but not JNK, were activated by KRAS(G12V) and we observed that proliferation and CAFC formation were mediated via ERK, while differentiation was predominantly mediated via p38. Interestingly, we observed that KRAS(G12V)-induced proliferation and CAFC formation, but not differentiation, were largely mediated via secreted factors, since these phenotypes could be recapitulated by treating non-transduced cells with conditioned medium harvested from KRAS(G12V)-transduced cultures. Multiplex cytokine arrays and genome-wide gene expression profiling were performed to gain further insight into the mechanisms by which oncogenic KRAS(G12V) can contribute to the process of leukemic transformation. Thus, angiopoietin-like 6 (ANGPTL6) was identified as an important factor in the KRAS(G12V) secretome that enhanced proliferation of human CB CD34(+) cells.

A novel adaptive method for the analysis of next-generation sequencing data to detect complex trait associations with rare variants due to gene main effects and interactions.

There is solid evidence that rare variants contribute to complex disease etiology. Next-generation sequencing technologies make it possible to uncover rare variants within candidate genes, exomes, and genomes. Working in a novel framework, the kernel-based adaptive cluster (KBAC) was developed to perform powerful gene/locus based rare variant association testing. The KBAC combines variant classification and association testing in a coherent framework. Covariates can also be incorporated in the analysis to control for potential confounders including age, sex, and population substructure. To evaluate the power of KBAC: 1) variant data was simulated using rigorous population genetic models for both Europeans and Africans, with parameters estimated from sequence data, and 2) phenotypes were generated using models motivated by complex diseases including breast cancer and Hirschsprung's disease. It is demonstrated that the KBAC has superior power compared to other rare variant analysis methods, such as the combined multivariate and collapsing and weight sum statistic. In the presence of variant misclassification and gene interaction, association testing using KBAC is particularly advantageous. The KBAC method was also applied to test for associations, using sequence data from the Dallas Heart Study, between energy metabolism traits and rare variants in ANGPTL 3,4,5 and 6 genes. A number of novel associations were identified, including the associations of high density lipoprotein and very low density lipoprotein with ANGPTL4. The KBAC method is implemented in a user-friendly R package.