Germline rearrangements in families with strong family history of glioma and malignant melanoma, colon, and breast cancer

BACKGROUND

Although familial susceptibility to glioma is known, the genetic basis for this susceptibility remains unidentified in the majority of glioma-specific families. An alternative approach to identifying such genes is to examine cancer pedigrees, which include glioma as one of several cancer phenotypes, to determine whether common chromosomal modifications might account for the familial aggregation of glioma and other cancers.

METHODS

Germline rearrangements in 146 glioma families (from the Gliogene Consortium; http://www.gliogene.org/) were examined using multiplex ligation-dependent probe amplification. These families all had at least 2 verified glioma cases and a third reported or verified glioma case in the same family or 2 glioma cases in the family with at least one family member affected with melanoma, colon, or breast cancer.The genomic areas covering TP53, CDKN2A, MLH1, and MSH2 were selected because these genes have been previously reported to be associated with cancer pedigrees known to include glioma.

RESULTS

We detected a single structural rearrangement, a deletion of exons 1-6 in MSH2, in the proband of one family with 3 cases with glioma and one relative with colon cancer.

CONCLUSIONS

Large deletions and duplications are rare events in familial glioma cases, even in families with a strong family history of cancers that may be involved in known cancer syndromes.

Global H3K27 trimethylation and EZH2 abundance in breast tumor subtypes

Polycomb repressive complex 2 (PRC2) and its core member enhancer of zeste homolog 2 (EZH2) mediate the epigenetic gene silencing mark: trimethylation of lysine 27 on histone 3 (H3K27me3). H3K27me3 is characteristic of the chromatin at genes involved in developmental regulation in undifferentiated cells. Overexpression of EZH2 has been found in several cancer types such as breast, prostate, melanoma and bladder cancer. Moreover, overexpression is associated with highly proliferative and aggressive types of breast and prostate tumors. We have analyzed the abundance of EZH2 and H3K27me3 using immunohistochemistry in two large and well-characterized breast tumor data sets encompassing more than 400 tumors. The results have been analyzed in relation to the molecular subtypes of breast tumors (basal-like, luminal A, luminal B, HER2-enriched and normal-like), as well as in subtypes defined by clinical markers (triple negative, ER+/HER2-/Ki67low, ER+/HER2-/Ki67high and HER2+), and were validated in representative breast cancer cell lines by western blot. We found significantly different expression of both EZH2 and H3K27me3 across all subtypes with high abundance of EZH2 in basal-like, triple negative and HER2-enriched tumors, and high H3K27me3 in luminal A, HER2-enriched and normal-like tumors. Intriguingly, the two markers show an inverse correlation, particularly for the basal-like and triple negative tumors. Consequently, high expression of EZH2 was associated with poor distant disease-free survival whereas high expression of H3K27me3 was associated with better survival. Additionally, none of 182 breast tumors was found to carry a previously described EZH2 mutation affecting Tyr641. Our observation that increased expression of EZH2 does not necessarily correlate with increased abundance of H3K27me3 supports the idea that EZH2 can have effects beyond epigenetic silencing of target genes in breast cancer.

Phosphatidylethanol: normalization during detoxification, gender aspects and correlation with other biomarkers and self-reports

Phosphatidylethanol (PEth) is a direct ethanol metabolite, and has recently attracted attention as biomarker of ethanol intake. The aims of the current study are: (1) to characterize the normalization time of PEth in larger samples than previously conducted; (2) to elucidate potential gender differences; and (3) to report the correlation of PEth with other biomarkers and self-reported alcohol consumption. Fifty-seven alcohol-dependent patients (ICD 10 F 10.25; 9 females, 48 males) entering medical detoxification at three study sites were enrolled. The study sample was comprised of 48 males and 9 females, with mean age 43.5. Mean gamma glutamyl transpeptidase (GGT) was 209.61 U/l, average mean corpuscular volume (MCV) was 97.35 fl, mean carbohydrate deficient transferrin (%CDT) was 8.68, and mean total ethanol intake in the last 7 days was 1653 g. PEth was measured in heparinized whole blood with a high-pressure liquid chromatography method, while GGT, MCV and %CDT were measured using routine methods. PEth levels at day 1 of detoxification ranged between 0.63 and 26.95 micromol/l (6.22 mean, 4.70 median, SD 4.97). There were no false negatives at day 1. Sensitivities for the other biomarkers were 40.4% for MCV, 73.1% for GGT and 69.2% for %CDT, respectively. No gender differences were found for PEth levels at any time point. Our data suggest that PEth is (1) a suitable intermediate term marker of ethanol intake in both sexes; and (2) sensitivity is extraordinary high in alcohol dependent patients. The results add further evidence to the data that suggest that PEth has potential as a candidate for a sensitive and specific biomarker, which reflects longer-lasting intake of higher amounts of alcohol and seemingly has the above mentioned certain advantages over traditional biomarkers.

Phosphatidylethanol as a sensitive and specific biomarker: comparison with gamma-glutamyl transpeptidase, mean corpuscular volume and carbohydrate-deficient transferrin

Phosphatidylethanol (PEth), a direct ethanol metabolite, is detectable in blood for more than 2 weeks after sustained ethanol intake. Our aim was to assess the usefulness of PEth [comparing sensitivity, specificity and the area under the curve (AUC)] as compared with carbohydrate-deficient transferrin (CDT), gamma-glutamyl transpeptidase (GGT) and mean corpuscular volume (MCV), calculating the results from sober patients against those from alcohol-dependent patients during withdrawal. Fifty-six alcohol-dependent patients (ICD-10 F 10.25) in detoxification, age 43 years, GGT 81 U/l, MCV 96.4 fl, %CDT 4.2, 1400 g ethanol intake in the last 7 days (median), were included in the study. Over the time of 1 year, 52 samples from 35 sober forensic psychiatric addicted in-patients [age 34 years, GGT 16 U/l, MCV 91 fl, CDT 0.5 (median)] in a closed ward were drawn and used for comparison . PEth was measured in heparinized whole blood with a high-performance liquid chromatography method. GGT, MCV and %CDT were measured using routine methods. A receiver operating characteristic curve analysis was carried out, with 'current drinking status' (sober/drinking) as the state variable and PEth, MCV, GGT and CDT as test variables. The resulting AUC was 0.974 (P < 0.0001, confidence interval 0.932-1.016) for PEth. At a cut-off of 0.36 micromol/l, the sensitivity was 94.5% and specificity 100%. The AUC for CDT, GGT and MCV were 0.931, 0.894 and 0.883, respectively. A significant Spearman's rank correlation was found between PEth and GGT (r = 0.739), CDT (r = 0.643), MVC (r = 0.639) and grams of ethanol consumed in the last 7 days (r = 0.802). Our data suggest that PEth has potential to be a sensitive and specific biomarker, having been found in previous studies to indicate longer lasting intake of higher amounts of alcohol.

PHosphatidylethanol (PEth) concentrations in blood are correlated to reported alcohol intake in alcohol-dependent patients

AIMS

Phosphatidylethanol (PEth) is an abnormal phospholipid formed only in the presence of ethanol by the enzyme phospholipase D. PEth in blood is a promising new marker for ethanol abuse. None of the biological markers used at the present time is sensitive and specific enough for the diagnosis of alcoholism.

METHODS

The most frequently used alcohol markers [carbohydrate deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and mean corpuscular volume (MCV)] were studied together with PEth in actively drinking alcohol-dependent patients (inpatients and outpatients), with regard to correlation to ethanol intake and diagnostic sensitivity of the markers. The relation between the markers was also studied.

RESULTS

PEth, CDT, and GGT correlated to ethanol intake, with the strongest correlation found for PEth. The diagnostic sensitivity for PEth was 99%, and for other markers it varied between 40 and 77%. Only when CDT was combined with GGT was a sensitivity of 94% reached. PEth correlated to CDT and GGT but not to MCV. CDT did not correlate to GGT or MCV.

CONCLUSIONS

Blood concentrations of PEth are highly correlated to ethanol intake, and the present results indicate that its diagnostic sensitivity is higher than that for previously established alcohol markers.

Methodological modifications on quantification of phosphatidylethanol in blood from humans abusing alcohol, using high-performance liquid chromatography and evaporative light scattering detection

Background

Phosphatidylethanol (PEth) is an abnormal phospholipid formed slowly in cell membranes by a transphosphatidylation reaction from phosphatidylcholine in the presence of ethanol and catalyzed by the enzyme phospholipase D. PEth in blood is a promising new marker of ethanol abuse depending on the high specificity and sensitivity of this marker. None of the biological markers used in clinical routine at the present time are sensitive and specific enough for the diagnosis of alcohol abuse.

The method for PEth analysis includes lipid extraction of whole blood, a one-hour HPLC separation of lipids and ELSD (evaporative light scattering) detection of PEth.

Results

Methodological improvements are presented which comprise a simpler extraction procedure, the use of phosphatidylbutanol as internal standard and a new algorithm for evaluation of unknown samples. It is further demonstrated that equal test results are obtained with blood collected in standard test tubes with EDTA as with the previously used heparinized test tubes. The PEth content in blood samples is stable for three weeks in the refrigerator.

Conclusion

Methodological changes make the method more suitable for routine laboratory use, lower the limit of quantification (LOQ) and improve precision.

Emerging Biomarkers: New Directions and Clinical Applications

This article summarizes content proceedings of a symposium held at the 2004 Research Society on Alcoholism Scientific Annual Meeting in Vancouver, Canada. The chairs were Friedrich M. Wurst and Raye Litten. The presentations were (1) Introduction, by Raye Litten; (2) Direct Ethanol Metabolites--On the Threshold From Science to Routine Use, by Friedrich M. Wurst; (3) Sialic Acid Index of Plasma Apolipoprotein J (SIJ) as a Viable Marker for Chronic Alcohol Consumption, by Philippe Marmillot; (4) The Emergence of Ethyl Glucuronide (EtG) Testing as a Tool in Monitoring Healthcare Professionals, by Gregory E. Skipper; (5) Application of Biomarkers for Alcohol Use Disorders in Clinical Practice, by Tim Neumann; (6) Utility of Biomarkers in Assessing the Efficacy of Medications for Treating Alcoholism, by Marty Javors; and (7) Discussion, by Raye Litten.

Phosphatidylethanol in rat organs after ethanol exposure

BACKGROUND

Phosphatidylethanol (PEth) is an abnormal phospholipid formed in mammalian cells that have been exposed to ethanol. It has been suggested that PEth mediates some of the damaging effects of ethanol on cells. This study was performed to investigate the level of PEth in organs of rats after in vivo alcohol exposure.

METHODS

Three exposure models were studied: (1) acute, intraperitoneal injection of ethanol (n = 3 x 3); (2) chronic, forced ethanol drinking (n = 6); and (3) chronic, free choice of ethanol (n = 20). PEth was analyzed by high-performance liquid chromatography after lipid extraction of the organs.

RESULTS

One acute injection gave detectable PEth levels in most organs analyzed, with maximal levels reached after 2 hr. The highest levels were reached in intestines, stomach, and lung. No PEth was detected in skeletal muscle, pancreas, or testis. The two exposure models for oral intake of ethanol also gave detectable PEth levels in most organs. The highest levels were reached in stomach, lung, and spleen. PEth was detected in muscle only in animals with heavy total alcohol intake.

CONCLUSIONS

PEth is formed in most organs of rats exposed to ethanol acutely or chronically. Variations in PEth level and rates of PEth formation and PEth degradation are organ specific.

Regulation of phospholipase D activity in neuroblastoma cells

The regulation of phospholipase D was studied in human neuroblastoma cells using phosphatidylethanol as a marker of the enzyme activity. Carbachol induced phospholipase D activity in SH-SY5Y cells. Muscarinic antagonists inhibited the response with potencies suggesting that muscarinic M1 receptors are responsible for the activation. In permeabilized SH-SY5Y cells, both the carbachol- and GTP gamma S-induced Peth formation was inhibited by GDP beta S, indicating that both responses are mediated via a G-protein. The protein kinase C inhibitors, bisindolylmaleimide and staurosporine significantly inhibited the carbachol-induced Peth formation whereas H7 had no effect. Thus, the cholinergic activation of phospholipase D in SH-SY5Y cells is probably mediated via a direct receptor-G-protein coupling but an involvement of protein kinase C cannot be excluded. Calmidazolium, a calmodulin antagonist, induced an increase in phosphatidylethanol formation in both SH-SY5Y and IMR-32 cells. This effect was inhibited by genistein and tyrphostin, indicating a tyrosine kinase dependent pathway for phospholipase D activation in neuroblastoma cells.

Protein kinase C-mediated phospholipase D activity is increased by linolenic acid supplementation in NG 108-15 cells

Phospholipase D activation was studied in NG 108-15 cells after manipulation of the phospholipid fatty acid composition. Cultivation of cells in media containing different polyunsaturated fatty acids induced extensive and specific changes in the phospholipid fatty acid composition. General for all phospholipids was an increase in polyunsaturated fatty acids at the expense of monounsaturated fatty acids. To examine phospholipase D activation, cells were stimulated with phorbol esters in the presence of ethanol and the formation of phosphatidylethanol was analyzed. In cells cultured with linolenic acid, a significantly higher amount of phosphatidylethanol was formed compared to control cells. On the other hand, supplementation with linoleic, arachidonic or docosahexaenoic acids did not induce any changes in phospholipase D activity. The effect was not due to free fatty acids in the cell culture medium and thus probably induced by fatty acids incorporated into membrane phospholipids or fatty acid metabolites. The results indicate a specific effect of linolenic acid and/or its metabolites on protein kinase C-mediated phospholipase D activity.

Phosphatidylethanol formation and degradation in brains of acutely and repeatedly ethanol-treated rats

The formation of the abnormal phospholipid phosphatidylethanol (PEth) was studied in hippocampus, cerebellum and cerebrum of rat brain after intraperitoneal ethanol administration. Prior to analysis by high performance thin layer chromatography PEth was purified. After one injection, PEth levels reached a maximum after 2 h and remained detectable for 14-24 h in all three regions. Repeated injections led to additional accumulation. Maximum in vivo levels of 30-50 nmol/g wet wt. were reached.

Agonist-stimulated and basal phosphatidylethanol formation in neutrophils from alcoholics

Phospholipase D has been shown to be a key enzyme in the signal transduction systems involved in neutrophil activation. In the presence of ethanol, the enzyme catalyzes a transphosphatidylation reaction through which phosphatidylethanol is formed instead of the normal product phosphatidic acid. The effects of ethanol on the formation of phosphatidylethanol and phosphatidic acid was studied in neutrophils from human alcoholics in vitro. Neutrophils were isolated and cellular lipids were labeled with [3H]oleate, whereafter the cells were preincubated with cytochalasin B. Subsequently, cells were stimulated with the chemotactic peptide formyl-Met-Leu-Phe in the presence of ethanol concentration ranging from 0 to 200 mM. In the presence of ethanol, both neutrophils from alcoholics and controls produced phosphatidylethanol, with a concomitant reduction of the production of phosphatidic acid. The amounts of phosphatidyl-ethanol and phosphatidic acid formed were dependent on the concentration of ethanol. In neutrophils from alcoholics, a higher apparent Km for the phospholipase D-mediated transphosphatidylation reaction was noted (58 mM ethanol compared with 28 mM in controls). The in vivo mass of phosphatidylethanol in recently drinking alcoholics was also analyzed in neutrophils. Measurable phosphatidyl-ethanol levels (average 5.6 pmol/10(8) neutrophils) were found in alcoholics up to 23 hr after the last intake of ethanol. Thus, in addition to the ethanol-induced changes in the normal production of phosphatidic acid, phosphatidylethanol accumulated in vivo in alcoholics may be expected to influence neutrophil function.

Ethanol alters the transfer of arachidonic acid to ethanolamine plasmalogens in C-6 glioma cells

In this study, the effects of ethanol exposure on uptake and metabolism of arachidonic acid by C-6 glioma cells in culture was examined. Labeled arachidonic acid was effectively taken up by the phospholipids of these cells and radioactivity was initially incorporated into phosphatidylinositols and phosphatidylcholines, reaching a peak between 4 and 6 hours. However, the labeling of ethanolamine plasmalogens continued to show an increase with time after labeled arachidonic acid has been exhausted in the medium. Since over 90% of labeled arachidonic acid was already taken up by the cells after 4 hours of exposure, the continued increase in labeling of ethanolamine plasmalogens is attributed to a transacylation mechanism. Cells grown in 150 mM ethanol for 2 days did not show a change in the overall incorporation of labeled arachidonic acid into phospholipids but showed a significant increase in labeling of ethanolamine plasmalogens, which was marked by a concomitant decrease in labeling of phosphatidylcholines. Ethanol exposure also resulted in a significant increase in the transfer of labeled arachidonic acid to triacylglycerols. Changes in phospholipid and triacylglycerol labeling pattern positively correlated with increasing ethanol concentration from 75 to 300 mM. Besides, most ethanol effects were readily noticeable after 24 hours of exposure. These data suggest a specific effect of ethanol on promoting the transacylase process for biosynthesis of ethanolamine plasmalogens as well as the acyltransferase for biosynthesis of triacylglycerols.

Bradykinin effects on phospholipid metabolism and its relation to arachidonic acid turnover in neuroblastoma x glioma hybrid cells (NG 108-15)

In neuroblastoma x glioma hybrid cells (NG 108-15) labelled with [32P]-trisodium phosphate, [3H]-inositol and [14C]-arachidonic acid, bradykinin stimulated the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) while it had no effect on the release of [14C]-arachidonic acid (AA). The effect on PIP2 was time- and dose-dependent with a maximal effect on [3H]-inositol- and [32P]-labelled cells after 10-30 s of stimulation with 10(-6) M bradykinin. However, the hydrolysis of [14C]-AA labelled PIP2 was delayed compared to the effect on [3H]- and [14C]-PIP2 and was not detectable until after 60 s of stimulation. Bradykinin stimulation resulted in an increased formation of [3H]-inositol phosphates (IP) and [32P]- and [14C]-phosphatidic acid (PA) but the time course for PA formation did not follow the time-course for PIP2 hydrolysis. A reduced labelling of [32P]- and [14C]-phosphatidylcholine was also found in stimulated cells suggesting that PA may derive from other sources than PIP2. In conclusion, our results indicate that bradykinin activates phospholipase C, but not phospholipase A2, in NG 108-15 cells.