Clinical relevance of glycerophospholipid,sphingomyelin and glutathione metabolism in the pathogenesis of pharyngolaryngeal cancer in smokers: the Korean Cancer Prevention Study-II

Introduction

Although smoking is a major risk factor for pharyngolaryngeal cancer, most smokers do not develop pharyngolaryngeal cancer.

Objectives

In the prospective Korean Cancer Prevention Study-II (KCPS-II), we investigated the application of metabolomics to differentiate smokers with incident pharyngolaryngeal cancer (pharyngolaryngeal cancer group) from smokers who remained free from cancer (controls) during a mean follow-up period of 7 years and aimed to discover valuable early biomarkers of pharyngolaryngeal cancer.

Methods

We used baseline serum samples from 30 smoking men with incident pharyngolaryngeal cancer and 59 age-matched cancer-free smoking men. Metabolic alterations associated with the incidence of pharyngolaryngeal cancer were investigated by performing metabolomics on baseline serum samples using ultra-performance liquid chromatography-linear-trap quadrupole-Orbitrap mass spectrometry.

Results

Compared to the control group, the pharyngolaryngeal cancer group showed significantly higher oxidized LDL levels. Seventeen metabolites were differentially abundant between the two groups. At baseline, compared to controls, smokers with incident pharyngolaryngeal cancer during follow-up showed significantly higher levels of pyroglutamic acid (glutathione metabolism) but lower levels of lysophosphatidylcholines (lysoPCs) C14:0, C15:0, C16:0, C17:0, C18:0, and C20:5; glycerophosphocholine; PC C36:5; lysoPEs C16:0, C20:1, and C22:0 (glycerophospholipid metabolism); SM (d18:0/16:1); and SM (d18:1/18:1) (sphingomyelin metabolism). Furthermore, smokers with incident pharyngolaryngeal cancer showed significantly higher levels of oleamide and lower levels of tryptophan and linoleyl carnitine at baseline than cancer-free smokers.

Conclusion

This prospective study showed the clinical relevance of dysregulated metabolism of glutathione, glycerophospholipids and sphingolipids to the pathogenesis of pharyngolaryngeal cancer among smokers. These data suggest that the dysregulation of these metabolic processes may be a key mechanism underlying pharyngolaryngeal cancer progression and development.

     

Body composition and breast cancer in postmenopausal women: a Danish prospective cohort study

Objective: To assess the importance of body fat mass (BFM) and fat free mass (FFM) for the established positive association between BMI and breast cancer among post‐menopausal women. Research Methods and Procedures: A prospective cohort of 23,788 postmenopausal women included in the Danish study Diet, Cancer, and Health during 1993 to 1997 was linked to the Danish Cancer Registry to identify all cases of breast cancer occurring during 1993 to 2002. Breast cancer incidence rate ratios for anthropometric measurements with adjustment for known risk factors for breast cancer were calculated by Cox regression analyses. Results: Among the most commonly used anthropometric measurements, BMI was positively associated with breast cancer among never users of hormone replacement therapy (HRT). By splitting BMI into two indices, BFM index and FFM index, we found that the incidence rate ratio with each 1 kg/m² among never users of HRT was 0.98 (95% confidence interval, 0.93 to 1.03) for BFM index and 1.12 (95% confidence interval, 1.00 to 1.26) for FFM index after mutual adjustment. Discussion: The finding for BMI was in accordance with previous findings. Our results indicate that the FFM component of BMI may play a role for development of breast cancer among never users of HRT.     

Estradiol stimulates the biosynthetic pathways of breast cancer cells: detection by metabolic flux analysis

Selective estrogen receptor (ER) modulators are highly successful breast cancer therapies, but they are not effective in patients with ER negative and selective estrogen receptor modulator (SERM)-resistant tumors. Understanding the mechanisms of estrogen-stimulated proliferation may provide a route to design estrogen-independent therapies that would be effective in these patients. In this study, metabolic flux analysis was used to determine the intracellular fluxes that are significantly affected by estradiol stimulation in MCF-7 breast cancer cells. Intracellular fluxes were calculated from nuclear magnetic resonance (NMR)-generated isotope enrichment data and extracellular metabolite fluxes, using a specific flux analysis algorithm. The metabolic pathway model used by the algorithm includes glycolysis, the tricarboxylic acid cycle (TCA cycle), the pentose phosphate pathway, glutamine catabolism, pyruvate carboxylase, and malic enzyme. The pathway model also incorporates mitochondrial compartmentalization and reversible trans-mitochondrial membrane reactions to more accurately describe the role of mitochondria in cancer cell proliferation. Flux results indicate that estradiol significantly increases carbon flow through the pentose phosphate pathway and increases glutamine consumption. In addition, intra-mitochondrial malic enzyme was found to be inactive and the malate-aspartate shuttle (MAS) was only minimally active. The inactivity of these enzymes indicates that glutamine is not oxidized within mitochondria, but is consumed primarily to provide biosynthetic precursors. The excretion of glutamine carbons from the mitochondria has the secondary effect of limiting nicotinamide adenine dinucleotide (NADH) recycle, resulting in NADH buildup in the cytosol and the excretion of lactate. The observed dependence of breast cancer cells on pentose phosphate pathway activity and glutamine consumption for estradiol-stimulated biosynthesis suggests that these pathways may be targets for estrogen-independent breast cancer therapies.     

Incidence of breast cancer in Norway and Sweden during introduction of nationwide screening: prospective cohort study

Objective To determine whether any increase in the incidence of breast cancer in women detected by mammography is compensated for by a drop in the incidence after age 69, years when women are no longer invited for screening.Design Population based cohort study of incidence of breast cancer during the introduction of nationwide screening programmes.Setting Norway and Sweden.Participants All women aged above 30 years (1.4 and 2.9 million, respectively, in 2000).Main outcome measures Changes in age specific incidence rates of invasive breast cancer associated with the introduction of the screening programmes.Results As a result of screening the recorded incidence of breast cancer in women aged 50-69 years increased by 54% in Norway and 45% in Sweden. There was no corresponding decline in incidence after the age of 69 years.Conclusions Without screening one third of all invasive breast cancers in the age group 50-69 years would not have been detected in the patients'' lifetime. This level of overdiagnosis is larger than previously reported.     

Steady-state modelling of metabolic pathways: A guide for the prospective simulator

Steady-state modelling and control analysis by means of computersimulation provides valuable insight into the behaviour of metabolicpathways. This review, which is aimed at the newcomer to thisfield, discusses the objectives of steady-state modelling andthe steady-state properties of the four basic metabolic structures,namely linear and branched chains, loops and cycles It is shownhow the model definition in terms of stoichiometric reactionsand rate equations leads to a set of balance equations fromwhich the conservation constraints and flux relationships canbe deduced, either informally or through a rigourous analysisof the stoichiometnc matrix The initial analysis of a steady-statemetabolic model is summarized in an algorithm. Key referencesto the literature on metabolic modelling are given.     

Alterations of metabolic genes and metabolites in cancer

Altered metabolic regulation has long been observed in human cancer and broadly used in the clinic for tumor detection. Two recent findings--the direct regulation of metabolic enzymes by frequently mutated cancer genes and frequent mutations of several metabolic enzymes themselves in cancer--have renewed interest in cancer metabolism. Supporting a causative role of altered metabolic enzymes in tumorigenesis, abnormal levels of several metabolites have been found to play a direct role in cancer development. The alteration of metabolic genes and metabolites offer not only new biomarkers for diagnosis and prognosis, but also potential new targets for cancer therapy.     

Cancer cachexia: mediators, signaling, and metabolic pathways

Cancer cachexia is characterized by a significant reduction in body weight resulting predominantly from loss of adipose tissue and skeletal muscle. Cachexia causes reduced cancer treatment tolerance and reduced quality and length of life, and remains an unmet medical need. Therapeutic progress has been impeded, in part, by the marked heterogeneity of mediators, signaling, and metabolic pathways both within and between model systems and the clinical syndrome. Recent progress in understanding conserved, molecular mechanisms of skeletal muscle atrophy/hypertrophy has provided a downstream platform for circumventing the variations and redundancy in upstream mediators and may ultimately translate into new targeted therapies.     

Multiple steroid metabolic pathways in ZR-75-1 human breast cancer cells

In order to characterize the main enzymatic systems involved in androgen and estrogen formation as well as metabolism in ZR-75-1 human breast cancer cells, incubation of intact cells was performed for 12 or 24 h at 37 degrees C with tritiated estradiol (E2), estrone (E1), androst-5-ene-3 beta, 17 beta-diol (5-ene-diol), dehydroepiandrosterone (DHEA), testosterone (T), androstenedione (4-ene-dione), dihydrotestosterone (DHT) or androsterone (ADT). The extra- and intracellular steroids were extracted, separated into free steroids, sulfates and non-polar derivatives (FAE) and identified by HPLC coupled to a Berthold radioactivity monitor. Following incubation with E2, 5-ene-diol or T, E1, DHEA and 4-ene-dione were the main products, respectively, thus indicating high levels of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD). When 4-ene-dione was used, on the other hand, a high level of transformation into 5 alpha-androstane-3,17-dione (A-dione), Epi-ADT and ADT was found, thus indicating the presence of high levels of 5 alpha-reductase as well as 3 alpha- and 3 beta-hydroxysteroid dehydrogenase. Moreover, some T was formed, due to oxidation by 17 beta-HSD. No estrogen was detected with the androgen precursors T or 4-ene-dione, thus indicating the absence of significant aromatase activity. Moreover, significant amounts of sulfates and non-polar derivatives were found with all the above-mentioned substrates. The present study shows that ZR-75-1 human breast cancer cells possess most of the enzymatic systems involved in androgen and estrogen formation and metabolism, thus offering an excellent model for studies of the control of sex steroid formation and action in breast cancer tissue.     

First-borns carry a higher metabolic risk in early adulthood: evidence from a prospective cohort study

Background

Birth order has been associated with early growth variability and subsequent increased adiposity, but the consequent effects of increased fat mass on metabolic risk during adulthood have not been assessed. We aimed to quantify the metabolic risk in young adulthood of being first-born relative to those born second or subsequently.

Methodology and Principal Findings

Body composition and metabolic risk were assessed in 2,249 men, aged 17–19 years, from a birth cohort in southern Brazil. Metabolic risk was assessed using a composite z-score integrating standardized measurements of blood pressure, total cholesterol, high density lipoprotein, triglycerides and fat mass. First-borns had lower birth weight z-score (Δ = −0.25, 95%CI −0.35, −0.15,p<0.001) but showed greater weight gain during infancy (change in weight z-score from birth to 20 months: Δ = 0.39, 95%CI 0.28–0.50, p<0.0001) and had greater mean height (Δ = 1.2 cm, 95%CI: 0.7–1.6, p<0.0001) and weight (Δ = 0.34 kg, 95%CI: 0.13–0.55, p<0.002) at 43 months. This greater weight and height tracked into early adulthood, with first-borns being significantly taller, heavier and with significantly higher fat mass than later-borns. The metabolic risk z-score was significantly higher in first-borns.

Conclusions/Significance

First-born status is associated with significantly elevated adiposity and metabolic risk in young adult men in Brazil. Our results, linking cardiovascular risk with life history variables, suggest that metabolic risk may be associated with the worldwide trend to smaller family size and it may interact with changes in behavioural or environmental risk factors.     

Stress and survival after cancer: a prospective study of a Finnish population-based cohort

Stress has been suggested to reduce survival after cancer, but the results of previous studies have been contradictory. We investigated the hypothesis in a national cohort of adults in Finland. Of those who completed the Stressful Life Events scale and the Stress of Daily Activities scale, 1470 and 1882, respectively, later had cancer and were included in the analysis, covering 23 years of follow-up between 1982 and 2004. In Cox regression analysis, the multivariate hazard ratio (HR) was 0.99 (95% confidence interval [CI], 0.96-1.01) for total number of life events and the HR for the life change score was 0.99 (95% CI, 0.95-1.03). Further, the HR was 0.92 (95% CI, 0.69-1.22) for severe daily stress. Overall, the results of the current study do not support the hypothesis that stress reduces cancer survival.     

Active cigarette smoking and the risk of breast cancer: a cohort study

BackgroundTobacco use has been implicated in the etiology of a large number of cancers, and there exists substantial biological plausibility that it could also be involved in breast carcinogenesis. Despite this, epidemiological evidence to date is inconsistent. The aim of this study was to investigate the role of active smoking and the risk of incident, invasive breast cancer using a prospective cohort of women from the Canadian Study of Diet, Lifestyle and Health.MethodsUsing a case-cohort design, an age-stratified subcohort of 3314 women was created from 39,532 female participants who returned completed self-administered lifestyle and dietary questionnaires at baseline. A total of 1096 breast cancer cases were identified in the entire cohort (including 141 cases from the subcohort) by linkage to the Canadian Cancer Registry. Cox regression models were used to estimate hazard ratios for the association between the different smoking exposures and the risk of breast cancer, using a modification for the case-cohort design.ResultsAfter carefully considering early-life exposures and potential confounders, we found no association between any smoking exposure and risk of breast cancer in this study (Hazard ratio = 1.00, 95% confidence interval = 0.87–1.17 for ever vs never smokers).ConclusionsAlthough these results cannot rule out an association between smoking and breast cancer, they do agree with the current literature suggesting that, if an association does exist, it is relatively weak.     

Prognostic significance of sealed-off perforation in colon cancer: a prospective cohort study

Background

Perforated colon cancer is a rare complication, but has a high risk of recurrence. However, most studies have not distinguished sealed-off perforation from free perforation, and the prognosis is unclear. The aim of this study was to evaluate the oncologic outcome of colon cancer with sealed-off perforation.

Methods

Eighty-six consecutive patients who underwent resection for colon cancer with sealed-off or free perforation were included. We defined sealed-off perforation as a colon perforation with localized abscess identified on operative, computed tomography, or pathologic findings, with no evidence of free perforation, including fecal contamination and dirty fluid collection in the peritoneal cavity. Oncologic outcomes were compared between patients with colon cancer with sealed-off perforation and free perforation using a log-rank test and Cox regression analysis.

Results

The sealed-off perforation group included 62 patients, and 24 patients were in the free perforation group. TNM stage and lymphatic, venous, and perineural invasion were similar between the groups. The median follow-up period was 28.9?months (range 0–159). The sealed-off perforation group had better prognosis compared with the free perforation group in terms of progression-free survival (PFS) and overall survival (OS), although there were no statistically significant differences in PFS (5-year PFS 53.7% vs. 40.5%, p?=?0.148; 5-year OS 53.6% vs. 22.9%, p?=?0.001). However, in multivariable analysis using the Cox progression test, sealed-off perforation did not show a significant effect on cancer progression (p =?0.138) and OS (p =?0.727).

Conclusions

Colon cancer with sealed-off perforation showed no difference in prognosis compared with free perforation.

     

Quantification of metabolites in the indole alkaloid pathways of catharanthus roseus: implications for metabolic engineering

In this article, we present a review of the current state of metabolic engineering in Catharanthus roseus. A significant amount of research has contributed to characterization of several individual steps in the biosynthetic pathway of medicinally valuable alkaloids. However, knowledge of the regulation of these pathways is still sparse. Using hairy root cultures, we studied the responses of alkaloid metabolism to environmental stimulation such as light and elicitation. Through precursor feeding studies, the putative rate-limiting steps of the terpenoid pathway in hairy root cultures also have been examined. Relating this knowledge to specific events at the molecular level, and the cloning of corresponding genes are the next key steps in metabolic engineering of the C. roseus alkaloids. Copyright 1998 John Wiley & Sons, Inc.     

Signaling pathways in breast cancer: Therapeutic targeting of the microenvironment

Breast cancer is the most common cancer in women worldwide. Understanding the biology of this malignant disease is a prerequisite for selecting an appropriate treatment. Cell cycle alterations are seen in many cancers, including breast cancer. Newly popular targeted agents in breast cancer include cyclin dependent kinase inhibitors (CDKIs) which are agents inhibiting the function of cyclin dependent kinases (CDKs) and agents targeting proto-oncogenic signaling pathways like Notch, Wnt, and SHH (Sonic hedgehog). CDKIs are categorized as selective and non-selective inhibitors of CDK. CDKIs have been tried as monotherapy and combination therapy. The CDKI Palbocyclib is now a promising therapeutic in breast cancer. This drug recently entered phase III trial for estrogen receptor (ER) positive breast cancer after showing encouraging results in progression free survival in a phase II trials.The tumor microenvironment is now recognized as a significant factor in cancer treatment response. The tumor microenvironment is increasingly considered as a target for combination therapy of breast cancer. Recent findings in the signaling pathways in breast cancer are herein summarized and discussed. Furthermore, the therapeutic targeting of the microenvironment in breast cancer is also considered.     

Antifungal compounds redirect metabolic pathways in yeasts: metabolites as indicators of modes of action

Aims: Metabolic pathways, e.g. biosynthesis of ergosterol or carbohydrate metabolism including respiration, are well‐known targets of several fungicides. With our study we wanted to prove that metabolite profiles can be used to classify fungicides according to their mode of action and that concentrations of key metabolites are changed even without detectable reduced growth rates. Methods and Results: We exposed the yeasts Candida albicans and Saccharomyces cerevisiae to inhibitors of the electron transport chain and to compounds known to interact with osmotic stress defence pathways. Glycerol and ethanol were chosen as key metabolites of branches of glucose catabolism. Increased glycerol concentrations were observed not only when the osmotic stress response was activated, but also as response to the inhibition of the electron transfer chain, whereas elevated ethanol levels were observed only when the respiratory pathways were blocked. Conclusions: The treatment of the yeasts Candida albicans and Saccharomyces cerevisiae with antimycotic compounds led to a redirection of metabolic pathways, which could be followed by the quantification of both the metabolites ethanol and glycerol. Only the combination of both concentration profiles allowed the clear distinction between inhibitors of the respiratory chain and effects on the osmotic stress response pathway. Impact of Study: The extension of the number of metabolites to a comprehensive quantitative metabolic profile of compound‐treated test organisms can be an additional tool in fungicide research allowing the detection of compounds which act on fungi and, moreover, the elucidation of modes of action.     

Genetic polymorphisms and cancer susceptibility of breast cancer in Korean women

Breast cancer is the most prevalent cancer among women in Western countries, and its prevalence is also increasing in Asia. The major risk factor for breast cancer can be traced to reproductive events that influence the lifetime levels of hormones. However, a large percentage of breast cancer cases cannot, be explained by these risk factors. The identification of susceptibility factors that predispose individuals to breast cancer (for instance, if they are exposed to particular environmental agents) could possibly give further insight into the etiology of this malignancy and provide targets for the future development of therapeutics. The most interesting candidate genes include those that mediate a range of functions. These include carcinogen metabolism, DNA repair, steroid hormone metabolism, signal transduction, and cell cycle control. we conducted a hospital-based case-control study on South Korea to evaluate the potential modifying role of the genetic pollymprphisms of selected low penetrance gens that are involved carcinogen metabolisms (i.e., CYP1A1, CYP2E1, GSTM1/T1/P1, NAT1/2, etc.), estrogen synthesis and metabolism (i.e., CYP19, CYP17, CYP1B1, COMT, ER-alpha, etc.), DNA repair (i.e., XRCC1/3, ERCC2/4, ATM, AGT, etc.), and signal transduction as well as others (i.e., TGF- beta, IGF-1, TNF- beta, IL-1B, IL-1RN, etc.). We also took into account the potential interaction between these and the known risk factors of breast cancer. The results of selected genes will be presented in this mini-review.     

定量监控大肠杆菌主代谢目标蛋白质及中间代谢物

摘要:【目的】监控大肠杆菌(Escherichia coli)主代谢通路上蛋白表达状况及中间代谢物变化,为代谢工程改造提供基础性数据及检测方法。【方法】利用Skyline软件靶向设计主代谢(糖酵解途径、磷酸戊糖途径、三羧酸循环、混合酸发酵途径及脂肪酸合成途径)目标蛋白质label-free (MRM)方法对其相对定量监控;在相同质谱平台(Triple Quad 4500)上利用LC-MS/MS(MRM)方法对目标中间代谢物绝对定量监控。【结果】实验表明不同生长时期内(对数生长期、稳定期及衰亡期)大肠杆菌主代谢蛋白质表达表现出4种不同的变化现象,某一代谢通路上的单一蛋白不能反映该通路的表达状态;磷酸戊糖途径、混合酸发酵途径以及三羧酸循环途径中较多的蛋白质在衰亡期表达量最高,但几种目标中间代谢产物(ATP、ADP、AMP、NAD+、NADH、NADP+、NADPH、CoA、acetyl-CoA)的积累量与对数生长期相比,稳定期及衰亡期都相应减少(除了acetyl-CoA以外)。【结论】该文中使用的检测方法可以有效地反映大肠杆菌体内代谢的基本状况。     

Overexpression of hypoxia-inducible factor and metabolic pathways: possible targets of cancer

Cancer, the main cause of human deaths in the modern world is a group of diseases. Anticancer drug discovery is a challenge for scientists because of involvement of multiple survival pathways of cancer cells. An extensive study on the regulation of each step of these pathways may help find a potential cancer target. Up-regulated HIF-1 expression and altered metabolic pathways are two classical characteristics of cancer. Oxygen-dependent (through pVHL, PHDs, calcium-mediated) and independent (through growth factor signaling pathway, mdm2 pathway, HSP90) regulation of HIF-1α leads to angiogenesis, metastasis, and cell survival. The two subunits of HIF-1 regulates in the same fashion through different mechanisms. HIF-1α translation upregulates via mammalian target of rapamycin and mitogen-activated protein kinase signaling pathways, whereas HIF-1β through calmodulin kinase. Further, the stabilized interactions of these two subunits are important for proper functioning. Also, metabolic pathways crucial for the formation of building blocks (pentose phosphate pathway) and energy generation (glycolysis, TCA cycle and catabolism of glutamine) are altered in cancer cells to protect them from oxidative stress and to meet the reduced oxygen and nutrient supply. Up-regulated anaerobic metabolism occurs through enhanced expression of hexokinase, phosphofructokinase, triosephosphate isomerase, glucose 6-phosphate dehydrogenase and down-regulation of aerobic metabolism via pyruvate dehydrogenase kinase and lactate dehydrogenase which compensate energy requirements along with high glucose intake. Controlled expression of these two pathways through their common intermediate may serve as potent cancer target in future.