Blood-Based DNA Methylation Analysis by Multiplexed OBBPA-ddPCR to Verify Indications for Prostate Biopsies in Suspected Prostate Cancer Patients

Current prostate carcinoma (PCa) biomarkers, including total prostate-specific antigen (tPSA), have unsatisfactory diagnostic sensitivity and specificity resulting in overdiagnosis and overtreatment. Previously, we described an optimised bias-based preamplification-digital droplet PCR (OBBPA-ddPCR) technique, which detects tumour DNA in blood-derived cell-free DNA (cfDNA) of cancer patients. The current study investigated the performance of newly developed OBBPA-ddPCR-based biomarkers. Blood plasma samples from healthy individuals (n = 90, controls) and PCa (n = 39) and benign prostatic hyperplasia patients (BPH, n = 40) were analysed. PCa and BPH patients had tPSA values within a diagnostic grey area of 2-15 ng/mL, for whom further diagnostic validation is most crucial. Methylation levels of biomarkers RASSF1A, MIR129-2, NRIP3, and SOX8 were found significantly increased in PCa patients compared to controls. By combining classical PCa risk factors (percentage of free PSA compared to tPSA (QfPSA) and patient's age) with cfDNA-based biomarkers, we developed PCa risk scores with improved sensitivity and specificity compared to established tPSA and QfPSA single-marker analyses. The diagnostic specificity was increased to 70% with 100% sensitivity for clinically significant PCa patients. Thus, prostate biopsies could be avoided for 28 out of 40 BPH patients. In conclusion, the newly developed risk scores may help to confirm the clinical decision and prevent unnecessary prostate biopsy.

Macrophage inclusions in cerebrospinal fluid following treatment initiation with antisense oligonucleotide therapies in motor neuron diseases

5q-associated spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are two distinct neurological disorders leading to degeneration of lower motor neurons. The antisense oligonucleotides (ASOs) nusinersen and tofersen are novel disease-modifying agents for these diseases, respectively. In the context of ASO treatment, the cytological characteristics and composition of cerebrospinal fluid (CSF) have recently garnered particular interest. This report presents a case series of CSF cytology findings in two patients with SMA and ALS revealing comparable unspecified macrophage inclusions following treatment initiation with nusinersen and tofersen. Yet, the presence of these "asophages" in the treatment course of two different ASOs is of unclear significance. While both treatments have been well tolerated, this phenomenon warrants attention, given the long-term nature of these treatments.

Tumour catabolism independent of malnutrition and inflammation in upper GI cancer patients revealed by longitudinal metabolomics

BACKGROUND

The detrimental impact of malnutrition and cachexia in cancer patients subjected to surgical resection is well established. However, how systemic and local metabolic alterations in cancer patients impact the serum metabolite signature, thereby leading to cancer-specific differences, is poorly defined. In order to implement metabolomics as a potential tool in clinical diagnostics and disease follow-up, targeted metabolite profiling based on quantitative measurements is essential. We hypothesized that the quantitative metabolic profile assessed by ¹ H nuclear magnetic resonance (NMR) spectroscopy can be used to identify cancer-induced catabolism and potentially distinguish between specific tumour entities. Importantly, to prove tumour dependency and assess metabolic normalization, we additionally analysed the metabolome of patients' sera longitudinally post-surgery in order to assess metabolic normalization.

METHODS

Forty two metabolites in sera of patients with tumour entities known to cause malnutrition and cachexia, namely, upper gastrointestinal cancer and pancreatic cancer, as well as sera of healthy controls, were quantified by ¹ H NMR spectroscopy.

RESULTS

Comparing serum metabolites of patients with gastrointestinal cancer with healthy controls and pancreatic cancer patients, we identified at least 15 significantly changed metabolites in each comparison. Principal component and pathway analysis tools showed a catabolic signature in preoperative upper gastrointestinal cancer patients. The most specifically upregulated metabolite group in gastrointestinal cancer patients was ketone bodies (3-hydroxybutyrate, P < 0.0001; acetoacetate, P < 0.0001; acetone, P < 0.0001; false discovery rate [FDR] adjusted). Increased glycerol levels (P < 0.0001), increased concentration of the ketogenic amino acid lysine (P = 0.03) and a significant correlation of 3-hydroxybutyrate levels with branched-chained amino acids (leucine, P = 0.02; isoleucine, P = 0.04 [FDR adjusted]) suggested that ketone body synthesis was driven by lipolysis and amino acid breakdown. Interestingly, the catabolic signature was independent of the body mass index, clinically assessed malnutrition using the nutritional risk screening score, and systemic inflammation assessed by CRP and leukocyte count. Longitudinal measurements and principal component analyses revealed a quick normalization of key metabolic alterations seven days post-surgery, including ketosis.

CONCLUSIONS

Together, the quantitative metabolic profile obtained by ¹ H NMR spectroscopy identified a tumour-induced catabolic signature specific to upper gastrointestinal cancer patients and enabled monitoring restoration of metabolic homeostasis after surgery. This approach was critical to identify the obtained metabolic profile as an upper gastrointestinal cancer-specific signature independent of malnutrition and inflammation.

The crucial role of epigenetic regulation in breast cancer anti-estrogen resistance: Current findings and future perspectives

Breast cancer (BC) cell de-sensitization to Tamoxifen (TAM) or other selective estrogen receptor (ER) modulators (SERM) is a complex process associated with BC heterogeneity and the transformation of ER signalling. The most influential resistance-related mechanisms include modifications in ER expression and gene regulation patterns. During TAM/SERM treatment, epigenetic mechanisms can effectively silence ER expression and facilitate the development of endocrine resistance. ER status is efficiently regulated by specific epigenetic tools including hypermethylation of CpG islands within ER promoters, increased histone deacetylase activity in the ER promoter, and/or translational repression by miRNAs. Over-methylation of the ER α gene (ESR1) promoter by DNA methyltransferases was associated with poor prognosis and indicated the development of resistance. Moreover, BC progression and spreading were marked by transformed chromatin remodelling, post-translational histone modifications, and expression of specific miRNAs and/or long non-coding RNAs. Therefore, targeted inhibition of histone acetyltransferases (e.g. MYST3), deacetylases (e.g. HDAC1), and/or demethylases (e.g. lysine-specific demethylase LSD1) was shown to recover and increase BC sensitivity to anti-estrogens. Indicated as a powerful molecular instrument, the administration of epigenetic drugs can regain ER expression along with the activation of tumour suppressor genes, which can in turn prevent selection of resistant cells and cancer stem cell survival. This review examines recent advances in the epigenetic regulation of endocrine drug resistance and evaluates novel anti-resistance strategies. Underlying molecular mechanisms of epigenetic regulation will be discussed, emphasising the utilization of epigenetic enzymes and their inhibitors to re-program irresponsive BCs.

Increased Sensitivity of Detection of RASSF1A and GSTP1 DNA Fragments in Serum of Prostate Cancer Patients: Optimisation of Diagnostics Using OBBPA-ddPCR

Identification of aberrant DNA methylation is a promising tool in prostate cancer (PCa) diagnosis and treatment. In this study, we evaluated a two-step method named optimised bias-based preamplification followed by digital PCR (OBBPA-dPCR). The method was used to identify promoter hypermethylation of 2 tumour suppressor genes RASSF1A and GSTP1 in the circulating cell-free DNA (cfDNA) from serum samples of PCa patients (n = 75), benign prostatic hyperplasia (BPH, n = 58), and healthy individuals (controls, n = 155). The PCa cohort was further subdivided into subgroups comprising (I) patients with Gleason Scores (GS) ≤ 7 (n = 55), (II) GS ≥ 8 (n = 10), and (III) patients with metastatic PCa diagnosis (n = 10). We found that RASSF1A methylation levels were significantly increased in all 3 PCa subgroups compared to the controls and BPH cohorts (p < 0.01 for all comparisons). Fractional abundances of methylated GSTP1 DNA fragments were significantly increased in subgroup III of metastatic PCa patients (p < 0.001). RASSF1A methylation analysis was found to be beneficial as a complementary biomarker where further diagnostic validation is most crucial. In combination with free PSA, RASSF1A methylation status helps to identify PCa patients with GS ≥ 8 and grey-zone total PSA values between 2-10 ng/mL. In our study, PCR biases between 80-90% were sufficient to detect minute amounts of tumour DNA with high signal-to-noise ratios as well as high analytical sensitivity and specificity. Both RASSF1A and GSTP1 exhibited strongly increased DNA methylation levels in all metastatic PCa patients. Our data indicates a superior sensitivity of epigenetic biomarker analyses in early detection of PCa metastases that should also help to improve PCa therapy.

Methylation of the Phospholipase A2 Receptor 1 Promoter Region in Childhood B Cell Acute Lymphoblastic Leukaemia

Acute lymphoblastic leukaemia (ALL) is the most common form of paediatric cancer and epigenetic aberrations are determinants of leukaemogenesis. The aim of this study was to investigate the methylation degree of a distinct phospholipase A2 receptor 1 (PLA2R1) promoter region in paediatric ALL patients and to evaluate its relevance as new biomarker for monitoring treatment response and burden of residual disease. The impact of PLA2R1 re-expression on proliferative parameters was assessed in vitro in Jurkat cells with PLA2R1 naturally silenced by DNA methylation. Genomic DNA was isolated from bone marrow (BM) and peripheral blood (PB) of 44 paediatric ALL patients. PLA2R1 methylation was analysed using digital PCR and compared to 20 healthy controls. Transfected Jurkat cells were investigated using cell growth curve analysis and flow cytometry. PLA2R1 was found hypermethylated in BM and PB from pre-B and common ALL patients, and in patients with the disease relapse. PLA2R1 methylation decreased along with leukaemic blast cell reduction during ALL induction treatment. In vitro analysis revealed an anti-proliferative phenotype associated with PLA2R1 re-expression, suggesting a tumour-suppressive function of PLA2R1. Collected data indicates that PLA2R1 promoter methylation quantitation can be used as biomarker for ALL induction treatment control, risk stratification, and early detection of ALL relapse.

Sphingosine kinase and sphingosine-1-phosphate receptor signaling pathway in inflammatory gastrointestinal disease and cancers: A novel therapeutic target

Inflammatory gastrointestinal (GI) diseases and malignancies are associated with growing morbidity and cancer-related mortality worldwide. GI tumor and inflammatory cells contain activated sphingolipid-metabolizing enzymes, including sphingosine kinase 1 (SphK1) and SphK2, that generate sphingosine-1-phosphate (S1P), a highly bioactive compound. Many inflammatory responses, including lymphocyte trafficking, are directed by circulatory S1P, present in high concentrations in both the plasma and the lymph of cancer patients. High fat and sugar diet, disbalanced intestinal flora, and obesity have recently been linked to activation of inflammation and SphK/S1P/S1P receptor (S1PR) signaling in various GI pathologies, including cancer. SphK1 overexpression and activation facilitate and enhance the development and progression of esophageal, gastric, and colon cancers. SphK/S1P axis, a mediator of inflammation in the tumor microenvironment, has recently been defined as a target for the treatment of GI disease states, including inflammatory bowel disease and colitis. Several SphK1 inhibitors and S1PR antagonists have been developed as novel anti-inflammatory and anticancer agents. In this review, we analyze the mechanisms of SphK/S1P signaling in GI tissues and critically appraise recent studies on the role of SphK/S1P/S1PR in inflammatory GI disorders and cancers. The potential role of SphK/S1PR inhibitors in the prevention and treatment of inflammation-mediated GI diseases, including GI cancer, is also evaluated.

Current insights into functions of phospholipase A2 receptor in normal and cancer cells: More questions than answers

Lipid signaling network was proposed as a potential target for cancer prevention and treatment. Several recent studies revealed that phospholipid metabolising enzyme, phospholipase A2 (PLA₂), is a critical regulator of cancer accelerating pathologies and apoptosis in several types of cancers. In addition to functioning as an enzyme, PLA₂ can activate a phospholipase A2 receptor (PLA2R1) in plasma membrane. While the list of PLA₂ targets extends to glucose homeostasis, intracellular energy balance, adipocyte development, and hepatic lipogenesis, the PLA2R1 downstream effectors are few and scarcely investigated. Among the most addressed PLA2R1 effects are regulation of pro-inflammatory signaling, autoimmunity, apoptosis, and senescence. Localized in glomeruli podocytes, the receptor can be identified by circulating anti-PLA2R1 autoantibodies leading to development of membranous nephropathy, a strong autoimmune inflammatory cascade. PLA2R1 was shown to induce activation of Janus-kinase 2 (JAK2) and estrogen-related receptor α (ERRα)-controlled mitochondrial proteins, as well as increasing the accumulation of reactive oxygen species, thus leading to apoptosis and senescence. These findings indicate the potential role of PLA2R1 as tumor suppressor. Epigenetic investigations addressed the role of DNA methylation, histone modifications, and specific microRNAs in the regulation of PLA2R1 expression. However, involvement of PLA2R1 in suppression of malignant growth and metastasis remains controversial. In this review, we summarize the recent findings that highlight the role of PLA2R1 in the regulation of carcinogenesis-related intracellular signaling.

Identification of rare levels of methylated tumor DNA fragments using an optimized bias based pre-amplification-digital droplet PCR (OBBPA-ddPCR)

BACKGROUND

The analysis of aberrant DNA methylations is used for the diagnosis of cancer as significant changes in the gene methylation pattern are often detected during early carcinogenesis. In this study, we evaluated the performance of a two-step method that combines pre-amplification with ddPCR technique.

RESULTS

By using ddPCR, the dependence of amplification efficiency for methylated and unmethylated DNA fragments on the relevant MgCl₂ concentration and the annealing temperature was established in addition to the primer design. We found that the efficiency can be adjusted toward methylated sequences by using primers covering one to four CpG sites under appropriately selected MgCl₂ concentration and annealing temperature. Applying a PCR bias between 85% and 95%, five copies of methylated tumor DNA fragments were detected against a background of 700,000 copies of unmethylated DNA fragments with a high signal-to-noise ratio. The analysis of serum samples from patients with prostate cancer showed a significantly improved performance of the new method in comparison with the MS-HRM technique, ddPCR alone, or ddPCR in combination with an unbiased pre-amplification using methylation-independent primers.

CONCLUSIONS

We define this method as an optimized bias-based pre-amplification-digital droplet PCR (OBBPA-ddPCR) technique. This novel method is recommended for the early detection of cancer-specific DNA methylation biomarkers in the form of a liquid biopsy.

Diverse effects of phospholipase A2 receptor expression on LNCaP and PC-3 prostate cancer cell growth in vitro and in vivo

Physiological and pathophysiological functions of the phospholipase A2 receptor 1 (PLA2R1) are still not completely understood. To elucidate PLA2R1’s function in prostate carcinoma, the receptor was ectopically overexpressed in LNCaP with silenced PLA2R1, and diminished in PC-3 cells with constitutively increased PLA2R1 expression relative to normal prostate epithelial cells. LNCaP cells were transfected to overexpress PLA2R1 (LNCaP-PLA2R1) and compared to control vector transfected cells (LNCaP-Ctrl). Alternatively, a CRISPR/Cas9-knockdown of PLA2R1 was achieved in PC-3 cells (PC-3 KD) and compared to the corresponding control-transfected cells (PC-3 Ctrl). The impact of PLA2R1 expression on proliferative and metastatic parameters was analysed in vitro. A pilot in vivo study addressed the effects of PLA2R1 in mice xenografted with transfected LNCaP and PC-3 cells. Cell viability/proliferation and motility were significantly increased in LNCaP-PLA2R1 and PC-3 Ctrl compared to LNCaP-Ctrl and PC-3 KD cells, respectively. However, levels of apoptosis, clonogenicity and cell invasion were reduced in LNCaP-PLA2R1 and PC-3 Ctrl cells. Gene expression analysis revealed an up-regulation of fibronectin 1 (FN1), TWIST homolog 1 (TWIST1), and cyclin-dependent kinase 6 (CDK6) in LNCaP-PLA2R1. In LNCaP xenografts, PLA2R1-dependent regulation of clonogenicity appeared to outweigh the receptor’s pro-oncogenic properties, resulting in decreased tumour growth, supporting the tumour-suppressive role of PLA2R1. Alternatively, PC-3 Ctrl xenografts exhibited faster tumour growth compared to PC-3 KD cells, suggesting a pro-oncogenic effect of endogenous PLA2R1 expression. The differential growth-regulatory effects of PLA2R1 may be mediated by FN1, TWIST1, and CDK6 expression, although further investigation is required.

Identification and Quantification of Heterogeneously-methylated DNA Fragments Using Epiallele-sensitive Droplet Digital Polymerase Chain Reaction (EAST-ddPCR)

BACKGROUND/AIM

DNA methylation plays an important role in the initiation and propagation of carcinogenesis; however, the role of heterogeneously methylated epialleles is currently not well studied, also due to the lack of sensitive, unbiased and high throughput methods. Here, a newly developed droplet digital PCR (ddPCR)-based method was evaluated regarding its ability to quantify such heterogeneously methylated epialleles with sufficient analytical sensitivity and specificity.

MATERIALS AND METHODS

Genomic DNA from blood leukocytes and bone marrow aspirate of an 8-year old male with B-cell acute lymphoblastic leukemia (B-ALL) and from normal and malignant prostate cell lines were analysed using ddPCR.

RESULTS

By using these DNA samples, the specificity of an applied set of fluorescence-labeled probes was demonstrated as a proof of concept.

CONCLUSION

All individual heterogeneously-methylated epialleles were quantifiable by a set of fluorescence-labeled probes with complementary sequences to epialleles in a closed-tube and high-throughput manner. The new method named epiallele-sensitive droplet digital PCR (EAST-ddPCR) may give new insights in the generation and regulation of epialleles and may help in finding new biomarkers for the diagnosis of benign und malignant diseases.

Regulatory role of sphingosine kinase and sphingosine-1-phosphate receptor signaling in progenitor/stem cells

Balanced sphingolipid signaling is important for the maintenance of homeostasis. Sphingolipids were demonstrated to function as structural components, second messengers, and regulators of cell growth and survival in normal and disease-affected tissues. Particularly, sphingosine kinase 1 (SphK1) and its product sphingosine-1-phosphate (S1P) operate as mediators and facilitators of proliferation-linked signaling. Unlimited proliferation (self-renewal) within the regulated environment is a hallmark of progenitor/stem cells that was recently associated with the S1P signaling network in vasculature, nervous, muscular, and immune systems. S1P was shown to regulate progenitor-related characteristics in normal and cancer stem cells (CSCs) via G-protein coupled receptors S1Pn (n = 1 to 5). The SphK/S1P axis is crucially involved in the regulation of embryonic development of vasculature and the nervous system, hematopoietic stem cell migration, regeneration of skeletal muscle, and development of multiple sclerosis. The ratio of the S1P receptor expression, localization, and specific S1P receptor-activated downstream effectors influenced the rate of self-renewal and should be further explored as regeneration-related targets. Considering malignant transformation, it is essential to control the level of self-renewal capacity. Proliferation of the progenitor cell should be synchronized with differentiation to provide healthy lifelong function of blood, immune systems, and replacement of damaged or dead cells. The differentiation-related role of SphK/S1P remains poorly assessed. A few pioneering investigations explored pharmacological tools that target sphingolipid signaling and can potentially confine and direct self-renewal towards normal differentiation. Further investigation is required to test the role of the SphK/S1P axis in regulation of self-renewal and differentiation.

Identification of CpG Sites of SERPINA5 Promoter with Opposite Methylation Patterns in Benign and Malignant Prostate Cells

BACKGROUND/AIM

To date there has been no investigation into the epigenetic regulation of the serine protease inhibitor SERPINA5 in prostate cancer, where lack of this gene was considered to facilitate invasive growth patterns.

MATERIALS AND METHODS

Methylation degrees of eight CpG sites of SERPINA5 were analyzed in normal and malignant prostate cells using nucleotide sequencing, methylation-specific high resolution melting and digital droplet PCR techniques.

RESULTS

The methylation degree of five CpG sites significantly correlated with lower SERPINA5 expression levels. In contrast, two CpG sites (at -19 bp and -14 bp from the transcription start site) were hypermethylated in normal epithelial prostate cells, benign hyperplasic cells and low-invasive malignant LNCaP cells, whereas in aggressive DU-145 and PC-3 cell lines, these sites were essentially unmethylated.

CONCLUSION

Novel methylation patterns of two distinct CpG sites of the SERPINA5 promoter may be useful for differentiating benign from malignant prostate disease.

Methods for comparing multiple digital PCR experiments

The estimated mean copy per partition (λ) is the essential information from a digital PCR (dPCR) experiment because λ can be used to calculate the target concentration in a sample. However, little information is available how to statistically compare dPCR runs of multiple runs or reduplicates. The comparison of λ values from several runs is a multiple comparison problem, which can be solved using the binary structure of dPCR data. We propose and evaluate two novel methods based on Generalized Linear Models (GLM) and Multiple Ratio Tests (MRT) for comparison of digital PCR experiments. We enriched our MRT framework with computation of simultaneous confidence intervals suitable for comparing multiple dPCR runs. The evaluation of both statistical methods support that MRT is faster and more robust for dPCR experiments performed in large scale. Our theoretical results were confirmed by the analysis of dPCR measurements of dilution series.

Both methods were implemented in the dpcR package (v. 0.2) for the open source R statistical computing environment.

Epigenetic Mutation of the Succinate Dehydrogenase C Promoter in a Patient With Two Paragangliomas

CONTEXT

Mutational inactivation of the succinate dehydrogenase (SDH) complex is a well-described cause of tumor development in pheochromocytomas/paragangliomas (PPGLs) and gastrointestinal stromal tumors (GISTs). Epigenetic inactivation of the SDHC gene is a more recently discovered phenomenon, which so far has only been described in GISTs and PPGLs from patients with Carney triad syndrome.

CASE DESCRIPTION

A 33-year-old patient presented with two abdominal paragangliomas (PGLs) and an adrenocortical adenoma. Both PGLs showed high succinate:fumarate ratios indicative of SDHx mutations; however, no mutations in any of the known PPGL susceptibility genes were found in leucocyte or tumor DNA. We identified methylation of the SDHC promoter region in both PGLs, which coincided with decreased SDHC expression at mRNA and protein levels and a hypermethylated epigenomic signature (CpG island methylator phenotype). Low-level SDHC promoter methylation was also observed in the adenoma but not in normal adrenal tissue or blood, suggesting postzygotic somatic mosaicism for SDHC promoter methylation in the patient.

CONCLUSIONS

This report provides evidence that SDHC promoter methylation can cause PGLs due to SDHC inactivation, emphasizing the importance of considering epigenetic changes and functional readouts in the genetic evaluation of patients not only with GISTs and Carney triad but also with PPGL.

Epigenetic control of group V phospholipase A2 expression in human malignant cells

Secreted phospholipases A2 (sPLA2) are suggested to play an important role in inflammation and tumorigenesis. Different mechanisms of epigenetic regulation are involved in the control of group IIA, III and X sPLA2s expression in cancer cells, but group V sPLA2 (GV-PLA2) in this respect has not been studied. Here, we demonstrate the role of epigenetic mechanisms in regulation of GV-PLA2 expression in different cell lines originating from leukaemia and solid cancers. In blood leukocytes from leukaemic patients, levels of GV-PLA2 transcripts were significantly lower in comparison to those from healthy individuals. Similarly, in DU-145 and PC-3 prostate and CAL-51 and MCF-7 mammary cancer cell lines, levels of GV-PLA2 transcripts were significantly lower in relation to those found in normal epithelial cells of prostate or mammary. By sequencing and methylation-specific high-resolution melting (MS-HRM) analyses of bisulphite-modified DNA, distinct CpG sites in the GV-PLA2 promoter region were identified that were differentially methylated in cancer cells in comparison to normal epithelial and endothelial cells. Spearman rank order analysis revealed a significant negative correlation between the methylation degree and the cellular expression of GV-PLA2 (r = -0.697; p = 0.01). The effects of demethylating agent (5-aza-2'-deoxycytidine) and histone deacetylase inhibitor (trichostatin A) on GV-PLA2 transcription in the analysed cells confirmed the importance of DNA methylation and histone modification in the regulation of the GV-PLA2 gene expression in leukaemic, prostate and mammary cancer cell lines. The exposure of tumour cells to human recombinant GV-PLA2 resulted in a reduced colony forming activity of MCF-7, HepG2 and PC-3 cells, but not of DU-145 cells suggesting a cell-type-dependent effect of GV-PLA2 on cell growth. In conclusion, our results suggest that epigenetic mechanisms such as DNA methylation and histone modification play an important role in downregulation of GV-PLA2 expression in cancer cells.

Epigenetic control of phospholipase A2 receptor expression in mammary cancer cells

BACKGROUND

It has recently been proposed that the M-type phospholipase A2 receptor (PLA2R1) acts as a tumour suppressor in certain malignancies including mammary cancer. Considering that DNA methylation is an important regulator of gene transcription during carcinogenesis, in the current study we analyzed the PLA2R1 expression, PLA2R1 promoter methylation, and selected micro RNA (miRNA) levels in normal human mammary epithelial cells (HMEC) and cancer cell lines.

METHODS

Levels of PLA2R1 and DNA methyltransferases (DNMT) specific mRNA were determined using real-time RT-PCR. Methylation specific-high resolution melting (MS-HRM) analysis was utilized to quantify the methylation degree of selected CpG sites localized in the promoter region of the PLA2R1 gene. Expression of miRNA was tested using miScript Primer Assay system.

RESULTS

Nearly complete methylation of the analyzed PLA2R1 promoter region along with PLA2R1 gene silencing was identified in MDA-MB-453 mammary cancer cells. In MCF-7 and BT-474 mammary cancer cell lines, a higher DNA methylation degree and reduced PLA2R1 expression were found in comparison with those in normal HMEC. Synergistic effects of demethylating agent (5-aza-2'-deoxycytidine) and histone deacetylase inhibitor (trichostatin A) on PLA2R1 transcription in MDA-MB-453 cells confirmed the importance of DNA methylation and histone modification in the regulation of the PLA2R1 gene expression in mammary cells. Furthermore, significant positive correlation between the expression of DNMT1 and PLA2R1 gene methylation and negative correlation between the cellular levels of hsa-mir-141, -181b, and -181d-1 and the expression of PLA2R1 were identified in the analyzed cells. Analysis of combined z-score of miR-23b, -154 and -302d demonstrated a strong and significant positive correlation with PLA2R1 expression.

CONCLUSIONS

Our data indicate that (i) PLA2R1 expression in breast cancer cells is controlled by DNA methylation and histone modifications, (ii) hypermethylation of the PLA2R1 promoter region is associated with up-regulation of DNMT1, and (iii) hsa-miR-23b, -154, and -302d, as well as hsa-miR-141, -181b, and -181d-1 are potential candidates for post-transcriptional regulation of PLA2R1 expression in mammary cancer cells.

Opposing effects of HIF1α and HIF2α on chromaffin cell phenotypic features and tumor cell proliferation: Insights from MYC-associated factor X

Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing chromaffin cell tumors with diverse phenotypic features reflecting mutations in numerous genes, including MYC-associated factor X (MAX). To explore whether phenotypic differences among PPGLs reflect a MAX-mediated mechanism and opposing influences of hypoxia-inducible factor (HIF)s HIF2α and HIF1α, we combined observational investigations in PPGLs and gene-manipulation studies in two pheochromocytoma cell lines. Among PPGLs from 140 patients, tumors due to MAX mutations were characterized by gene expression profiles and intermediate phenotypic features that distinguished these tumors from other PPGLs, all of which fell into two expression clusters: one cluster with low expression of HIF2α and mature phenotypic features and the other with high expression of HIF2α and immature phenotypic features due to mutations stabilizing HIFs. Max-mutated tumors distributed to a distinct subcluster of the former group. In cell lines lacking Max, re-expression of the gene resulted in maturation of phenotypic features and decreased cell cycle progression. In cell lines lacking Hif2α, overexpression of the gene led to immature phenotypic features, failure of dexamethasone to induce differentiation and increased proliferation. HIF1α had opposing actions to HIF2α in both cell lines, supporting evolving evidence of their differential actions on tumorigenic processes via a MYC/MAX-related pathway. Requirement of a fully functional MYC/MAX complex to facilitate differentiation explains the intermediate phenotypic features in tumors due to MAX mutations. Overexpression of HIF2α in chromaffin cell tumors due to mutations affecting HIF stabilization explains their proliferative features and why the tumors fail to differentiate even when exposed locally to adrenal steroids.

Silibinin down-regulates expression of secreted phospholipase A2 enzymes in cancer cells

BACKGROUND

Silibinin, a naturally-occurring flavonoid produced by milk thistle, possesses antioxidant, anti-inflammatory and cancer-preventive activities. In the current study, we examined the effects of silibinin on the expression of secreted phospholipase A2 (sPLA2) enzymes, especially those of group IIA (hGIIA), which play a crucial role in inflammation and carcinogenesis.

MATERIALS AND METHODS

The effects of silibinin on sPLA2 expressions in human HepG2 hepatoma and PC-3 prostate cancer cells were analyzed using quantitative reverse transcription-polymerase chain reaction and enzyme linked immunosorbent assay technique.

RESULTS

Silibinin inhibited the expression of hGIIA in unstimulated and cytokine-primed HepG2 and PC-3 cells. The mRNA levels of sPLA2 of groups IB, III and V were also significantly decreased by silibinin. Analyses of transcription factor activation suggest that nuclear factor-κB, but not specificity protein 1 (SP1) is implicated in the silibinin-mediated down-regulation of hGIIA.

CONCLUSION

Silibinin exhibits inhibitory effects on basal and cytokine-induced expression of sPLA2s in cancer cells and therefore, may have the potential to protect against up-regulation of hGIIA and other sPLA2 isoforms during inflammation and cancer.

Novel parameters of extended complete blood cell count under fluorescence flow cytometry in patients with sepsis

BACKGROUND

We first describe a patient who developed urosepsis from an ordinary urinary tract infection. In this case, the new hematological parameters of immature leukocytes, that is, the high-fluorescence lymphocyte cell (HFLC) and immature granulocyte (IG) counts peaked early, whereas the established infection parameters, that is, C-reactive protein (CRP) and total white blood cell count showed less dynamic regarding infection and therapy.

METHODS

To investigate this phenomenon in greater detail, the novel parameters HFLC and IG counts are investigated retrospectively in a cohort of 38 patients who were admitted to the anesthesia intensive care unit. Three groups of patients have been analyzed and compared: patients without signs of infection, patients with limited infections, and patients with sepsis. Data were collected with a Sysmex XE-5000 hematological analyzer.

RESULTS

In patients (n = 22) without any signs of infection, both values are very low. In patients with limited local infections (n = 10), moderate elevations of the IG and HFLC counts are seen. In patients with sepsis (n = 6), the IG and HFLC counts are significantly higher.

CONCLUSION

The total IG count seems to be useful for distinguishing a septic patient from a nonseptic (P < 0.004). Hematological parameters have the advantage of being measured easily during routine blood cell analysis.

Deregulated expression of urokinase and its inhibitor type 1 in prostate cancer cells: role of epigenetic mechanisms

Plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator (uPA) play a crucial role in cancer progression. In the present study we examined the regulation of PAI-1 and uPA expressions in normal prostate epithelial cells (PrEC) and the prostate cancer cell lines LNCaP, DU-145, and PC-3. The antigen and mRNA levels of PAI-1 were down-regulated in cancer cells, especially in LNCaP and DU-145. In the presence of proinflammatory cytokines, an increase of PAI-1 mRNA levels was observed in PrEC, LNCaP and PC-3, but not in DU-145 cells. Treatment with demethylating agent, 5-aza-2'-deoxycytidine increased the level of PAI-1 transcript in DU-145 cells and restored the inducing effect of cytokines on PAI-1 expression. An aberrant methylation of PAI-1 promoter in DU-145 and LNCaP cells was shown by methylation-sensitive high resolution melting (MS-HRM) analysis. PAI-1 methylation was also significantly increased in tumor samples (23.2±1.7%) in comparison to adjacent non-tumor tissue (6.0±0.8%). Furthermore, the expression of uPA was increased in high invasive cell lines DU-145 and PC-3 in comparison to PrEC and low invasive LNCaP cells. MS-HRM analysis revealed aberrant methylation of uPA promoter in LNCaP cells, but not in PrEC, DU-145 and PC-3 cells, as well as in normal and prostate cancer tissue samples. In conclusion, the study shows that PAI-1 and uPA expressions were changed in opposite directions in high invasive prostate cancer cell lines resulting in a strong decrease of PAI-1/uPA ratio, which may indicate a shift towards proteolytic activities. Methylation of the PAI-1 gene is suggested as one of the molecular mechanisms involved in the cancer-associated down-regulation of the PAI-1 expression.

Double stable isotope ultra performance liquid chromatographic-tandem mass spectrometric quantification of tissue content and activity of phenylethanolamine N-methyltransferase, the crucial enzyme responsible for synthesis of epinephrine

Here, we describe a novel method utilizing double stable isotope ultra performance liquid chromatography-tandem mass spectrometry to measure tissue contents and activity of phenylethanolamine N-methyltransferase (PNMT), the enzyme responsible for synthesis of the stress hormone, epinephrine. The method is based on measurement of deuterium-labeled epinephrine produced from the reaction of norepinephrine with deuterium-labeled S-adenosyl-L-methionine as the methyl donor. In addition to enzyme activity, the method allows for determination of tissue contents of PNMT using human recombinant enzyme for calibration. The calibration curve for epinephrine was linear over the range of 0.1 to 5,000 pM, with 0.5 pM epinephrine representing the lower limit of quantification. The calibration curve relating PNMT to production of deuterium-labeled epinephrine was also linear from 0.01 to 100 ng PNMT. Intra- and inter-assay coefficients of variation were respectively 12.8 % (n = 10) and 10.9 to 13.6 % (n = 10). We established utility of the method by showing induction of the enzyme by dexamethasone in mouse pheochromocytoma cells and strong relationships to PNMT gene expression and tissue epinephrine levels in human pheochromocytomas. Development of this assay provides new possibilities for investigations focusing on regulation of PNMT, the crucial final enzyme responsible for synthesis of epinephrine, the primary fight-or-flight stress hormone.

Aberrant methylation of the M-type phospholipase A(2) receptor gene in leukemic cells

Background

The M-type phospholipase A2 receptor (PLA2R1) plays a crucial role in several signaling pathways and may act as tumor-suppressor. This study examined the expression and methylation of the PLA2R1 gene in Jurkat and U937 leukemic cell lines and its methylation in patients with myelodysplastic syndrome (MDS) or acute leukemia.

Methods

Sites of methylation of the PLA2R1 locus were identified by sequencing bisulfite-modified DNA fragments. Methylation specific-high resolution melting (MS-HRM) analysis was then carried out to quantify PLA2R1 methylation at 5`-CpG sites identified with differences in methylation between healthy control subjects and leukemic patients using sequencing of bisulfite-modified genomic DNA.

Results

Expression of PLA2R1 was found to be completely down-regulated in Jurkat and U937 cells, accompanied by complete methylation of PLA2R1 promoter and down-stream regions; PLA2R1 was re-expressed after exposure of cells to 5-aza-2´-deoxycytidine. MS-HRM analysis of the PLA2R1 locus in patients with different types of leukemia indicated an average methylation of 28.9% ± 17.8%, compared to less than 9% in control subjects. In MDS patients the extent of PLA2R1 methylation significantly increased with disease risk. Furthermore, measurements of PLA2R1 methylation appeared useful for predicting responsiveness to the methyltransferase inhibitor, azacitidine, as a pre-emptive treatment to avoid hematological relapse in patients with high-risk MDS or acute myeloid leukemia.

Conclusions

The study shows for the first time that PLA2R1 gene sequences are a target of hypermethylation in leukemia, which may have pathophysiological relevance for disease evolution in MDS and leukemogenesis.

Regulation of thrombomodulin expression in prostate cancer cells

In carcinomas the expression of thrombomodulin (TM) is inversely correlated with tumour progression and metastasis. In the present study a decreased TM expression in human prostate cancer cell lines, LNCaP, DU-145, and PC-3, in relation to normal prostate epithelial cells (PrEC) is shown. Sequencing and methylation-specific high resolution melting (MS-HRM) analyses of bisulphite-modified genomic DNA indicates a high degree of methylation in DU-145 cells and lesser degrees in PC-3 and LNCaP cells, whereas in PrEC the TM promoter is unmethylated. The expression of TM is negatively regulated by NF-κB- and GSK3-β-dependent signalling pathways and positively regulated by retinoic acid and transcription factor Sp1 in PrEC, LNCaP and PC-3 cells, but not in DU-145 cells. However, exposure of DU-145 cells to the demethylating agent, 5-aza-2'deoxycytidine, restores the TM expression and its control by retinoic acid, NF-κB- and GSK3-β-dependent signalling. In conclusion, the study establishes that in prostate cancer cell lines relative to PrEC the TM is down-regulated and that the TM promoter is hypermethylated, which seems to be responsible for the down-regulation and failed regulation of TM expression in DU-145 cells.

Abstract A159: Epigenetic silencing of the M-type phospholipase A2 receptor gene in leukemic cells

Background: The M-type phospholipase A2 receptor (PLA2R) plays a crucial role in a number of different signaling pathways and may act as tumor-suppressor. In the current study the expression and methylation of the PLA2R gene in the myeloid U937 cell line and blood leukocytes of patients with leukemia were analyzed. Methods. Expression of PLA2R in U937 cells was studied using RT-quantitative PCR. To determine methylation levels of the PLA2R locus, bisulfite-modified DNA fragments were sequenced. Identification of different 5′-CpG methylation sites in normal and leukemic patients was followed by methylation specific-high resolution melting (MS-HRM) analysis to quantify PLA2R methylations.

Results: Our data establish that expression of PLA2R is completely down-regulated in U937 cells. Simultaneously, a 100% methylation of PLA2R promoter and down-stream regions was found in this cell line; after exposure of the cells to 5-aza-2 -deoxycytidine, PLA2R was re-expressed. MS-HRM analyzes in 34 patients with different types of leukemia indicated an average PLA2R methylation of 30%±18%, whereas in 52 normal subjects methylation levels were below 10%. In a preliminary study of high-risk myelodysplastic syndrome patients (MDS), three patients had increased PLA2R methylations. In the course of treatment with azacitidine (Vidaza) as methyltransferase inhibitor, two of these patients were responders in contrast to one patient who was a non-responder with increased methylation levels in blood leukocytes during treatment. Another patient with minimal residual disease after treatment of AML underwent preemptive treatment with azacitidine to avoid hematological relapse (HR). After two azacitidine cycles a minor cell fraction with 100% methylated PLA2R was completely diminished. However, three weeks later methylation of the PLA2R promoter increased to 50%, with 9% blasts detectable in blood samples. After further azacitidine treatment cycle, blasts diminished in blood samples but the methylation of PLA2R in blood leukocytes remained at 35%. During the following seven weeks with no further azacitidine treatment blasts increased up to 44% suggesting that the treatment with azacitidine was effective but not efficient enough to prevent a HR in this patient.

Conclusions: The study shows for the first time that the PLA2R promoter and down-stream regions in leukemic cells are hypermethylated and that the determination of PLA2R methylation by MS-HRM may be useful as a biomarker in the diagnosis and therapeutic treatment of high-risk MDS and AML patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A159.

Regulation of endothelial protein C receptor shedding by cytokines is mediated through differential activation of MAP kinase signaling pathways

The endothelial protein C receptor (EPCR) plays a pivotal role in coagulation, inflammation, cell proliferation, and cancer, but its activity is markedly changed by ectodomain cleavage and release as the soluble protein (sEPCR). In this study we examined the mechanisms involved in the regulation of EPCR shedding in human umbilical endothelial cells (HUVEC). Interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), but not interferon-gamma and interleukin-6, suppressed EPCR mRNA transcription and cell-associated EPCR expression in HUVEC. The release of sEPCR induced by IL-1beta and TNF-alpha correlated with activation of p38 MAPK and c-Jun N-terminal kinase (JNK). EPCR shedding was also induced by phorbol 12-myristate 13-acetate, ionomycin, anisomycin, thiol oxidants or alkylators, thrombin, and disruptors of lipid rafts. Both basal and induced shedding of EPCR was blocked by the metalloproteinase inhibitors, TAPI-0 and GM6001, and by the reduced non-protein thiols, glutathione, dihydrolipoic acid, dithiothreitol, and N-acetyl-l-cysteine. Because other antioxidants and scavengers of reactive oxygen species failed to block the cleavage of EPCR, a direct suppression of metalloproteinase activity seems responsible for the observed effects of reduced thiols. In summary, the shedding of EPCR in HUVEC is effectively regulated by IL-1beta and TNF-alpha, and downstream by MAP kinase signaling pathways and metalloproteinases.

On interaction of activated protein C with human aortic smooth muscle cells attenuating the secretory group IIA phospholipase A2 expression

INTRODUCTION

Pharmacological restriction of secretory group IIA phospholipase A(2) (sPLA(2)-IIA) expression is thought to be beneficial in the treatment of inflammatory diseases such as sepsis and septic shock. In this study we investigated the effects of activated protein C (APC) on sPLA(2)-IIA expression, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, and on DNA-binding activities of nuclear factor-kappaB (NF-kappaB) and CCAAT box enhancer binding protein-beta (C/EBP-beta) in human aortic smooth muscle cells (HASMC).

MATERIALS AND METHODS

To achieve elevated sPLA(2)-IIA production as occurring during inflammation, HASMC were stimulated with interferon-gamma (IFN-gamma) alone and in combination with other inductors, thus modeling the strong sPLA(2)-IIA elevation by inflammation.

RESULTS AND CONCLUSIONS

APC inhibited the stimulated expression of sPLA(2)-IIA in HASMC dose-dependently (1-300 nM). At the same time, APC increased the phosphorylation of ERK 1/2 and decreased NF-kappaB and C/EBP-beta DNA-binding activities in these cells, as compared with respective stimulated controls. Reverse transcriptase-polymerase chain reaction and cell-based ELISA reveal an endothelial protein C receptor (EPCR) expression in HASMC. Application of antibodies against EPCR and protease-activated receptor-1 (PAR-1) reduced the APC-induced ERK 1/2 activation and the treatment of cells with a PAR-1 antagonist diminished the sPLA(2)-IIA inhibition. The obtained results show that APC effectively suppresses the up-regulated sPLA(2)-IIA expression, which might contribute to the reported beneficial effects of APC in the treatment of severe inflammatory disorders.

Mechanism of inhibition of human secretory phospholipase A2 by flavonoids: rationale for lead design

The human secretory phospholipase A2 group IIA (PLA2-IIA) is a lipolytic enzyme. Its inhibition leads to a decrease in eicosanoids levels and, thereby, to reduced inflammation. Therefore, PLA2-IIA is of high pharmacological interest in treatment of chronic diseases such as asthma and rheumatoid arthritis. Quercetin and naringenin, amongst other flavonoids, are known for their anti-inflammatory activity by modulation of enzymes of the arachidonic acid cascade. However, the mechanism by which flavonoids inhibit Phospholipase A2 (PLA2) remained unclear so far. Flavonoids are widely produced in plant tissues and, thereby, suitable targets for pharmaceutical extractions and chemical syntheses. Our work focuses on understanding the binding modes of flavonoids to PLA2, their inhibition mechanism and the rationale to modify them to obtain potent and specific inhibitors. Our computational and experimental studies focused on a set of 24 compounds including natural flavonoids and naringenin-based derivatives. Experimental results on PLA2-inhibition showed good inhibitory activity for quercetin, kaempferol, and galangin, but relatively poor for naringenin. Several naringenin derivatives were synthesized and tested for affinity and inhibitory activity improvement. 6-(1,1-dimethylallyl)naringenin revealed comparable PLA2 inhibition to quercetin-like compounds. We characterized the binding mode of these compounds and the determinants for their affinity, selectivity, and inhibitory potency. Based on our results, we suggest C(6) as the most promising position of the flavonoid scaffold to introduce chemical modifications to improve affinity, selectivity, and inhibition of PLA2-IIA by flavonoids.

Mice lacking the nuclear pore complex protein ALADIN show female infertility but fail to develop a phenotype resembling human triple A syndrome

Triple A syndrome is a human autosomal recessive disorder characterized by adrenal insufficiency, achalasia, alacrima, and neurological abnormalities affecting the central, peripheral, and autonomic nervous systems. In humans, this disease is caused by mutations in the AAAS gene, which encodes ALADIN, a protein that belongs to the family of WD-repeat proteins and localizes to nuclear pore complexes. To analyze the function of the gene in the context of the whole organism and in an attempt to obtain an animal model for human triple A syndrome, we generated mice lacking a functional Aaas gene. The Aaas-/- animals were found to be externally indistinguishable from their wild-type littermates, although their body weight was on the average lower than that of wild-type mice. Histological analysis of various tissues failed to reveal any differences between Aaas-/- and wild-type mice. Aaas-/- mice exhibit unexpectedly mild abnormal behavior and only minor neurological deficits. Our data show that the lack of ALADIN in mice does not lead to a triple A syndrome-like disease. Thus, in mice either the function of ALADIN differs from that in humans, its loss can be readily compensated for, or additional factors, such as environmental conditions or genetic modifiers, contribute to the disease.

Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases?

Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.

The relevance of the detection of troponins to the forensic diagnosis of cardiac contusion

The forensic diagnosis of cardiac contusion has hitherto been based mainly on anamnesis, concomitant thoracic injuries and the detection of macroscopic changes to the heart. Parallel histological and serological investigations of the heart-specific troponins have been conducted with varying results. This paper aims to show whether heart-specific troponins are suitable as a means of securing the diagnosis in proven cases of cardiac contusion and of determining which of the three heart-specific troponins cTnT, cTnI and cTnC are most significant in serology and histology for postmortem diagnosis. In the study, 25 cases of known cardiac contusion and 11 controls without vital myocardial trauma taken from autopsy material were prospectively investigated. Investigation of the venous serum revealed significant differences in the concentrations of the case and control groups for troponin T (mean value 5.5056 versus 0.4982; p=0.014), for troponin C (mean value 263.9280 versus 68.5640; p=0.001) and for troponin I (mean value 1404.0560 versus 36.1650; p=0.003). In histology there are also significantly different depletions between the groups investigated (cTnT: p=0.002; cTnC: p=0.003; cTnI: p<0.001) taking into account the autolysis time.

Impact of glucagon response on postprandial hyperglycemia in men with impaired glucose tolerance and type 2 diabetes mellitus

Glucagon is the physiological antagonist of insulin. Postprandial (pp) hyperglycemia in impaired glucose tolerance (IGT) and in type 2 diabetes mellitus (T2DM) may also depend on irregularities in glucagon secretion. This study investigated the glucagon excursion after a lipid-glucose-protein tolerance test in subjects with different stages of glucose intolerance. We also analyzed the relationship between pp glucagon secretion and hyperglycemias. A total of 64 men (27 healthy subjects with normal glucose tolerance [NGT], 15 with IGT, and 22 with T2DM) were examined. Plasma glucose (PG), insulin, proinsulin, free fatty acids, and triglycerides were measured in the fasting state and at 30 minutes and 2, 3, 4, and 6 hours after the intake of the test meal, which contained 126 g carbohydrates, 92 g fat, and 17 g protein. Postprandial concentrations of metabolic parameters were calculated as area under the curve (AUC). Glucagon was measured in the fasting state and at 30 minutes and 2 and 4 hours pp. Early glucagon increment was defined as glucagon at 30 minutes minus fasting glucagon. The insulin response was quantified as insulin increment divided by PG increment in the corresponding time. Insulin resistance was calculated using lomeostasis model assessment (HOMA). Fasting glucagon was significantly increased in IGT vs NGT (P<.05), and early glucagon increment was significantly higher in T2DM vs NGT and IGT (P<.05). The 2-hour glucagon concentration after the load (AUC) was increased in IGT and T2DM vs NGT (P<.05). Early glucagon increment and the 2-hour AUC of glucagon were strongly correlated to pp glycemia (r=0.494 and P=.001, and r=0.439 and P=.003, respectively). An inverse correlation was observed between early glucagon increment and insulin response at 30 minutes and 2 hours after the meal load (r=-0.287 and P=.026, and r=-0.435 and P=.001, respectively). The 2-hour AUC of glucagon was significantly associated with insulin resistance (r=0.354, P=.020). Multivariate analysis revealed 2-hour insulin response and early glucagon increment as significant independent determinants of the AUC of PG in IGT (R=0.787). In T2DM, 2-hour insulin response, insulin resistance, and early glucagon increment were significant determinants of the AUC of PG (R=0.867). Our study suggests an important role for the irregularities in glucagon response in the pp glucose excursion after a standardized oral mixed meal in IGT and in T2DM. According to our data, a bihormonal imbalance starts before diabetes is diagnosed. Prospective studies are needed to evaluate the impact of glucagon on the progression of glucose intolerance and the possible effects of medicinal suppression of glucagon increment to prevent the progression of glucose tolerance.

Statins potentiate the IFN-γ-induced upregulation of group IIA phospholipase A2 in human aortic smooth muscle cells and HepG2 hepatoma cells

The present study shows that the incubation of human aortic smooth muscle cells (HASMC) and HepG2 cells with atorvastatin and mevastatin as HMG-CoA reductase inhibitors potentiated the interferon-gamma (INF-gamma)-induced group IIA phospholipase A(2) (sPLA(2)-IIA) expression in a dose- and time-dependent manner. The effect of statins on sPLA(2)-IIA expression was reduced by mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate. Inversely, inhibitors of the farnesyl transferase and geranylgeranyl transferase-I mimicked the effects of statins. Clostridium difficile toxin B (TcdB), Y-27632 and H-1152, functioning as inhibitors of Rho proteins and Rho-associated kinase, also augmented the sPLA(2)-IIA expression in combination with IFN-gamma. The same effects were observed when inhibitors of mitogen-activated/extracellular response protein kinase kinase (MEK), PD98059 or U0126 were used. Further, the Janus kinase-2 (Jak2)-specific inhibitor, AG-490 and inhibitors of nuclear factor-kappaB (NFkappaB) abrogated the sPLA(2)-IIA elevating effects of statins, TcdB and PD98059 in the presence of IFN-gamma. This cytokine alone increased the NFkappaB p65 and CAAT-enhancer-binding protein-beta (C/EBP-beta) activity in HASMC nuclear extract, but only C/EBP-beta was further augmented when the cells were incubated in addition to IFN-gamma with atorvastatin, H-1152, PD98059 or U0126. Moreover, after the incubation of cells with atorvastatin and IFN-gamma the stability of sPLA-(2)IIA mRNA significantly increased in comparison to those after incubation with IFN-gamma alone. In conclusion, the obtained data suggest that (i) the expression of sPLA(2)-IIA is negatively regulated by RhoA/Rho-associated kinase and MEK/ERK signaling pathways and (ii) statins, because of their ability to down-regulate these pathways, can potentiate the IFN-gamma-induced sPLA(2)-II expression at transcriptional and post-transcriptional levels.

Glycogen synthase kinase-3beta negatively regulates group IIA phospholipase A2 expression in human aortic smooth muscle and HepG2 hepatoma cells

The present study shows that the IFN-gamma-mediated upregulation of secretory phospholipase A2 of group IIA (sPLA2-IIA) in HASMC and HepG2 cells is synergistically increased after simultaneous inhibition of glycogen synthase kinase-3beta (GSK-3beta) by indirubin-3'-monoxime, 5-iodo or AR-A014418. The effect of GSK-3beta inhibition was dose- and time-dependent and can be further augmented by its concomitant incubation with Clostridium difficile toxin B, an inhibitor of small Rho proteins, or H-1152, an inhibitor of Rho-associated kinase. Using AG-490 and caffeic acid phenethyl ester (CAPE), it is further demonstrated that the effect of GSK-3beta inhibition on sPLA2-IIA expression depends on Janus kinase-2 and NF-kappaB-signaling.

Increased hepatic cholesterol accumulation in transgenic mice overexpressing human secretory phospholipase A2 group IIA

It has been demonstrated in transgenic mice that the overexpression of human phospholipase A2 group IIA (sPLA2), an acute-phase reactant, is associated with depressed plasma cholesterol levels, altered lipoprotein compositions, and increased lipid depositions in aortic walls. It was the aim of the present study to investigate whether the reduced plasma cholesterol levels in sPLA2-transgenic mice may be due to an increased transfer of lipids from sPLA2-modified lipoproteins to the liver and/or other nonvascular tissues. Ten sPLA2-transgenic mice and an equal number of nontransgenic littermates were fed a cholesterol-enriched (1%) diet for 13 weeks. After autopsy, cholesterol and triglyceride concentrations were measured in homogenates of liver, spleen, kidney, and myocardial tissues. Compared to the nontransgenic controls, the sPLA2-transgenic mice exhibited significantly lower plasma cholesterol levels, which was due to a reduction in both HDL and beta-lipoprotein (LDL + beta-VLDL) cholesterol. Liver tissues from the transgenic mice were found to contain significantly increased concentrations of free and esterified cholesterol, which was not associated with increased triglyceride concentrations. Spleen, kidney, and heart tissues of the two animal groups showed no significant differences in cholesterol or triglyceride concentrations. The findings suggest that the overexpression of human secretory phospholipase A2 group IIA leads to an enhanced delivery of cholesterol from phospholipolysed lipoproteins to the liver. This mechanism is likely to contribute to the development of hypocholesterolemia observed in patients with inflammatory diseases.

Omega-3 fatty acids improve liver and pancreas function in postoperative cancer patients

Epidemiologic studies have indicated that high intake of saturated fat and/or animal fat increases the risk of colon and breast cancer. Omega-3 PUFAs in fish oil (FO) can inhibit the growth of human cancer cells in vitro and in vivo. These effects are related to the uptake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into the cellular substrate pool and their competitive metabolism with arachidonic acid (AA) at the cyclooxygenase and 5-lipoxygenase levels. The metabolites of EPA and DHA have less inflammatory and immunosuppressant potency than the substances derived from AA. Based on previous experimental data, we hypothesized that FO supplementation after major abdominal cancer surgery would improve hepatic and pancreatic function. Ours was a prospective, randomized, double-blinded clinical trial on 44 patients undergoing elective major abdominal surgery, randomly assigned to receive total parenteral nutrition (TPN) supplemented with either soybean oil (SO 1.0 g/kg body weight daily, n = 20) for 5 days or a combination of FO and SO (FO 0.2 + SO 0.8 g/kg body weight daily, n = 24). Compared to pure SO supplementation in the postoperative period, FO significantly reduced ASAT [0.8 +/- 0.1 vs. 0.5 +/- 0.1 mmol/(l. sec)], ALAT [0.9 +/- 0.1 vs. 0.6 +/- 0.1 mmol/(l. sec)], bilirubin (16.1 +/- 5.3 vs. 6.9 +/- 0.6 mmol/l), LDH (7.7 +/- 0.4 vs. 6.7 +/- 0.4 mmol/(l. sec) and lipase (0.6 +/- 0.1 vs. 0.4 +/- 0.1 micromol/(l. sec) in the postoperative course. Moreover, patients with increased risk of sepsis (IL-6/IL-10 ratio >8) showed a tendency to shorter ICU stay (18 hr) under omega-3 PUFA treatment. Weight loss as encountered after the SO emulsion of 1.1 +/- 2.2 kg was absent in the FO group. After major abdominal tumor surgery, FO supplementation improved liver and pancreas function, which might have contributed to the faster recovery of patients.

Adrenocortical hormones in survivors and nonsurvivors of severe sepsis: diverse time course of dehydroepiandrosterone, dehydroepiandrosterone-sulfate, and cortisol

OBJECTIVE

Activation and suppression of immune responses are crucial events during sepsis. Based on substantial new data, a complex picture of differential immune-enhancing and immunosuppressive actions of adrenocortical steroids is emerging. The adrenal androgen dehydroepiandrosterone and its precursor, dehydroepiandrosterone-sulfate, show a considerable decrease with increasing age and serve as functional antagonists to endogenous glucocorticoids. Therefore, we examined time-dependent changes in dehydroepiandrosterone, dehydroepiandrosterone-sulfate, cortisol, adrenocorticotropin, and inflammatory variables in surviving and nonsurviving patients with severe sepsis.

DESIGN

Prospective observational study in consecutive patients.

SETTING

Medical and interdisciplinary intensive care units in two university hospitals and one city hospital.

PATIENTS

Thirty nonsurgical patients (25 men and 5 women) with severe sepsis (American College of Chest Physicians/Society of Critical Care Medicine criteria); 15 survivors (mean age, 54 +/- 14 yrs; Acute Physiology and Chronic Health Evaluation III score, 59 +/- 35) and 15 nonsurvivors (mean age, 63 +/- 15 yrs; Acute Physiology and Chronic Health Evaluation III score, 67 +/- 24) were included. Hormones were compared individually and between survivors/nonsurvivors by sequential blood drawings from early sepsis till time of recovery/death.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During early sepsis, cortisol (nmol/L) was not significantly higher in survivors than nonsurvivors (750 +/- 121 vs. 454 +/- 92, p <.08) and decreased in survivors (p <.01) during late sepsis. During early sepsis, dehydroepiandrosterone-sulfate (percentage of age-matched normal levels) was higher in survivors than nonsurvivors (85 +/- 19 vs. 22 +/- 7, p <.01). Dehydroepiandrosterone-sulfate decreased in survivors (p =.0001) but remained low in nonsurvivors during late sepsis. Dehydroepiandrosterone (percentage of age-matched normal levels) was not significantly elevated in survivors compared to nonsurvivors during early sepsis (282 +/- 42 vs. 214 +/- 63, p <.08). Dehydroepiandrosterone decreased in survivors (p <.01) but not in nonsurvivors during late sepsis. Linear regression for dehydroepiandrosterone levels showed a reconstitution of age dependence only in survivors during recovery. Adrenocorticotropin levels did not change. The dehydroepiandrosterone-sulfate/cortisol ratio decreased significantly in both survivors and nonsurvivors, whereas dehydroepiandrosterone/cortisol ratio only decreased in survivors during course of sepsis.

CONCLUSIONS

During sepsis, adrenal androgens and glucocorticoids show a diverse time-dependent course in survivors and nonsurvivors.

Biological effects of secretory phospholipase A(2) group IIA on lipoproteins and in atherogenesis

Secretory phospholipase A(2) group IIA(sPLA(2) IIA) can be produced and secreted by various cell types either constitutionally or as an acute-phase reactant upon stimulation by proinflammatory cytokines. The enzyme prefers phosphatidylethanolamine and phosphatidylserine as substrates. One important biological function may be the hydrolytic destruction of bacterial membranes. It has been demonstrated, however, that sPLA(2) can also hydrolyse the phospholipid monolayers of high density lipoprotein (HDL) and low density lipoprotein (LDL) in vitro. Secretory phospholipase A(2)-modified LDL show increased affinity to glycosaminoglycans and proteoglycans, a tendency to aggregate, and an enhanced ability to deliver cholesterol to cells. Incubation of cultured macrophages with PLA(2)-treated LDL and HDL is associated with increased intracellular lipid accumulation, resulting in the formation of foam cells. Elevated sPLA(2)(IIA) activity in blood serum leads to an increased clearance of serum cholesterol. Secretory phospholipase A(2)(IIA) can also be detected in the intima, adventitia and media of the atherosclerotic wall not only in developed lesions but also in very early stages of atherosclerosis. The presence of DNA of Chlamydia pneumoniae, herpes simplex virus, and cytomegalovirus was found to be associated with sPLA(2)(IIA) expression and other signs of local inflammation. Thus, sPLA(2)(IIA) appears to be one important link between the lipid and the inflammation hypothesis of atherosclerosis.

Different effects of acarbose and glibenclamide on proinsulin and insulin profiles in people with Type 2 diabetes

AIM

In a double-blind, placebo-controlled study, we compared the effect of acarbose (A) and glibenclamide (G) on post-prandial (pp) and 24-h profiles of proinsulin and insulin.

METHODS

Twenty-seven patients with Type 2 diabetes mellitus insufficiently controlled with diet alone were randomised to receive acarbose, 100 mg thrice daily, glibenclamide, 1 mg thrice daily, or placebo. Before and after 16 weeks of treatment, 24-h profiles of proinsulin, insulin and glucose (fasting, 1 h after breakfast and every 3-h for a 24-h period) were measured under metabolic ward conditions with standardised meals.

RESULTS

With acarbose, a reduced 24-h level of proinsulin was observed compared with glibenclamide (AUC 1096 +/- 118 vs. 1604 +/- 174 pmol/l per h, P<0.05) at 16 weeks. The breakfast increment of proinsulin was lower with acarbose than glibenclamide (6.8 vs. 19.3 pmol/l, P<0.05) as was the level at that time (37.3 +/- 5.3 vs. 56.4 +/- 7.5 pmol/l, P<0.05). A lower AUC of insulin after treatment was also observed with acarbose than glibenclamide (7.9 +/- 0.9 vs. 14.8 +/- 4.5 nmol/l per h, P<0.05), as also for 1-h increment (81 +/- 26, vs. 380 +/- 120 pmol/l, P<0.01) and 1-h level (325 +/- 30 vs. 621 +/- 132 pmol/l, P<0.01). Acarbose reduced 1-h breakfast glucose increment (baseline 6.3 +/- 0.6, 16-week 3.5 +/- 0.6 mmol/l, P<0.01) and 1-h glucose level (18.1 +/- 1.1 and 14.5 +/- 1.3 mmol/l, P<0.01), whereas glibenclamide did not (6.6 +/- 0.7 vs. 5.4 +/- 0.6 mmol/l and 18.9 +/- 1.5 vs. 15.3 +/- 1.3 mmol/l).

CONCLUSIONS

Measurement of circadian excursions of proinsulin and insulin reveals distinct differences in meal-time proinsulin and insulin increment and level between acarbose and glibenclamide whereas fasting levels of these insulin fractions remained unaffected.

[Urinary concentration of collagen metabolites in endoprosthesis loosening]

Aseptic loosening is the most common long-term complication in arthroplasty. Loosening is in every case associated with bone resorption at the interface that leads to bone defects and complicates the revision. The diagnosis of aseptic loosening is based on clinical and radiological evaluation. Especially in clinically asymptomatic cases an early diagnosis with these methods is difficult. In our study we wanted to evaluate the diagnostic value of biochemical markers of the bone resorption in aseptic loosening. We compared 58 patients with proven implant loosening during surgery with 67 patients without clinical or radiological signs of loosening. We measured the crosslinks pyridinoline and hydroxypyridinoline in urine samples. In contrast to Schneider et al. [increased urinary crosslink levels in aseptic loosening of total hip arthroplasty, J. Arthroplasty 1995; 13 (6): 687-692] we found no significant differences between loose and asymptomatic hip or knee prosthesis. Also no correlation between the size of the acetabular defects of loose hip implants and the urinary crosslink excretion was measurable. Our results show no or only little diagnostic value of the urinary crosslinks pyridinoline and deoxypyridinoline in aseptic loosening of total hip and knee arthroplasty.

Impaired glucose tolerance (IGT) is not associated with disturbed homocysteine metabolism

Elevated plasma total homocysteine (tHcy) has been suggested to be an additional risk factor for cardiovascular disease in subjects with impaired glucose tolerance (IGT) and Type 2 diabetes (T2D). In order to investigate whether an insulin resistant/chronic hyperinsulinemic situation in male diabetic and prediabetic subjects directly influences the tHcy metabolism, fasting tHcy and post-methionine load tHcy plasma levels (PML-tHcy) were determined in 15 men with IGT, 13 men with newly diagnosed T2D, and 16 normoglycemic controls (NGT). Fasting tHcy (IGT, 13.1 +/- 4.6; T2D, 12.8 +/- 4.0; NGT, 10.7 +/- 4.4 micromol/L) and PML-tHcy (IGT, 46.5 +/-17.39; T2D, 41.1 +/- 6.8; NGT, 38.0 +/- 9.7 micromol/L) showed no differences between the groups. Fasting tHcy and PML-tHcy correlated with fasting proinsulin (r = 0.395, p < 0.05; r = 0.386, p< 0.05) and creatinine (r = 0.489, p < 0.01; r = 0.339, p < 0.05), resp. Multiple regression analysis showed only a relationship between fasting tHcy and creatinine. No relationships have been found between fasting tHcy and PML-tHcy, resp., and indicators of an insulin resistant state, e.g., insulin and proinsulin, as well as serum cobalamin and folate concentrations. In conclusion, our data suggest that the degree of glucose intolerance has no direct impact on the metabolism of homocysteine. However, tHcy levels tend to be elevated with the development of nephropathy, indicating an association between tHcy and renal function in these subjects.

In situ reverse transcriptase-nested polymerase chain reaction to identify intracellular nucleic acids without the necessity of DNAse pretreatment and hybridisation

In the present study a protocol of in situ reverse transcriptase-nested polymerase chain reaction (in situ RT-nested PCR) was examined based on the following modifications. (i) To exclude false positive signals caused by "DNA repair mechanisms" and "endogenous priming", a two-step PCR was applied after reverse transcription. The first step was performed in the presence of extrinsic primers and unlabeled nucleotides with a maximum of PCR cycles possible without destroying the cell morphology. The second step consisted of only one annealing/elongation reaction, the target sequence marked by addition of digoxigenin-labeled nucleotides and intrinsic primers. (ii) In order to prevent amplifications of genomic DNA nested primer pairs were applied crossing intron sequences. (iii) To minimize the diffusion of PCR products in cells, the extrinsic primers were extended with complementary 5(prime, variant)-tails. This approach results in the generation of high molecular weight concatamers during PCR cycles. By applying this protocol, immunostainings specific for phospholipase A2 of type IIA mRNA were exclusively detectable in the cytoplasm of HepG2 hepatoma cells, which were used as a model system, whereas the nuclei were unstained. Multiple control experiments yielded completely negative results. These data suggest that the in situ RT-nested PCR, which in comparison to the method of in situ RT-PCR-in situ-hybridisation is simpler and less time-consuming, can be used as an alternative approach to identify intracellular nucleic acids.

Interleukin-1, interleukin-6 and myocardial enzyme response after coronary artery bypass grafting - a prospective randomized comparison of the conventional and three minimally invasive surgical techniques

OBJECTIVE

In order to evaluate the traumatic effects of median sternotomy and cardiopulmonary bypass (CPB) in conventional and minimally invasive coronary artery bypass grafting, inflammatory response was studied in a prospective randomized trial in patients referred to single-vessel coronary artery bypass grafting.

METHODS

Four surgical techniques were compared: group 1, median sternotomy with CPB in ten patients (eight male, two female; aged 59.6+/-11.0 years (mean+/-SD)); group 2, median sternotomy and off-pump in ten patients (seven male, three female; aged 65.1+/-10.0 years); group 3, minithoracotomy with CPB in ten patients (seven male, three female, aged 61.2+/-10.4 years); group 4, minithoracotomy and off-pump in ten patients (nine male, one female, aged 62.9+/-9.8 years). All patients received a left internal mammary artery graft to the left anterior descending artery (LAD). Clinical data, perioperative values of cytokines and cardiac enzymes were monitored.

RESULTS

There were no major complications. Troponin-T and creatine kinase isoenzyme MB (CK-MB) levels were significantly higher in CPB procedures (P<0.0056; multivariate general linear model). Interleukin-6 (IL-6) levels were significantly higher in minithoracotomy procedures. Interleukin-1 (IL-1) was significantly increased in all patients compared with the preoperative values.

CONCLUSIONS

The use of CPB is combined with higher levels of troponin-T and CK-MB as signs of myocardial damage. Surgical access was identified as a trigger of inflammatory response, as minithoracotomy is related to higher levels of IL-6. IL-1 increased in all procedures and this occurred independently of the surgical access or the use of CPB, which points out a potential relationship between inflammatory response and anesthesia. Neither CPB nor surgical access influenced the clinical outcome in the treatment of coronary artery single-vessel bypass grafting.

Diagnostic significance of prostate-specific antigen velocity at intermediate PSA serum levels in relation to the standard deviation of different test systems

Serial prostate-specific antigen (PSA) measurements (PSA velocity) as an additional instrument to detect prostatic cancer was introduced in 1992. It has previously been reported that PSA increase per year differed in the last 5 years prior to diagnosis in patients with benign prostatic hyperplasia (0.18 ng/ml/year), locally confined (0.75 ng/ml/year) and metastasized (4.4 ng/ml/year) cancer of the prostate (CaP) in contrast to healthy men (0.04 ng/ml/year). The ability of PSA velocity to detect organ-confined CaP in patients with intermediate PSA serum values depends therefore on a reliable and reproducible PSA result. The present study comprised 85 men with PSA values between 3 and 8 ng/ml (Abbott IMx). PSA measurements were repeated with Abbott IMx (n = 85 patients) and Hybritech Tandem-E (n = 59 patients) assays. The PSA serum values differed from one examination to the other from 0.02 to 2.74 ng/ml with the Abbott IMx. Standard deviation amounted to 0.35 ng/ml with the Abbott IMx PSA assay. Using the Hybritech Tandem-E assay, mean standard deviation was 1.15 ng/ml and therefore higher than with the Abbott IMx assay. The difference from one test to the other ranged from 0.05 to 4.05 ng/ml with the Hybritech Tandem-E. Using the Abbott IMx assay, 10.6% of all repeat measurements exceeded 1 ng/ml whereas in the Hybritech Tandem-E assay 62.7% of the second measurements differed > 1 ng/ml from the first PSA result. An increase in PSA serum values may therefore be due to intratest variation, physiological day-to-day variation as well as prostatic disease. It is important to notice that the intra-assay variation may be greater than the PSA increase per year in a patient with CaP. Therefore, PSA velocity seems to be of limited value.

Expression of secretory group IIA phospholipase A(2) in relation to the presence of microbial agents, macrophage infiltrates, and transcripts of proinflammatory cytokines in human aortic tissues

Recent seroepidemiological and immunohistochemical studies have demonstrated an association between microbial infections and atherosclerosis. However, the mechanisms underlying this association are widely unknown. In the present study, arterial specimens obtained at autopsy after sudden death were analyzed concerning (1) the presence of Chlamydia pneumoniae, cytomegalovirus, herpes simplex virus, and Helicobacter pylori; (2) the expression of secretory group IIA phospholipase A(2) (sPLA(2)-IIA) and of proinflammatory cytokines; and (3) the stage of atherosclerosis. Genomic DNA of microbial pathogens was determined by the polymerase chain reaction technique. The expression of sPLA(2)-IIA was studied immunohistochemically by using monoclonal antibodies against human sPLA(2)-IIA. Transcripts specific for sPLA(2)-IIA, interleukin-1beta, tumor necrosis factor-alpha, and interferon-gamma were identified by reverse transcription-polymerase chain reaction. In 18 of 102 analyzed specimens, DNA of microbial pathogens was found. Thirteen sections were positive for C pneumoniae, whereas 2 specimens were positive either for cytomegalovirus or for herpes simplex virus. One section contained genomic DNA of all 3 pathogens simultaneously. None of the analyzed tissues exhibited nucleic acids specific for H pylori. In addition to macrophage infiltrates, the presence of microbial DNA was closely associated with the occurrence of transcripts specific for proinflammatory cytokines and sPLA(2)-IIA. Pathogens as well as sPLA(2)-IIA and cytokines were found to be present not only in advanced but also in early stages of atherosclerosis. In tissues negative for sPLA(2)-IIA and cytokine expression, none of the pathogens could be identified. Because macrophages exposed to phospholipase A(2)-treated lipoproteins are transformed into foam cells in vitro, the results of this study suggest an alternative mechanism by which microbial infections may act in a proatherogenic fashion in vessel walls.