Human beta-defensin-1, a potential chromosome 8p tumor suppressor: control of transcription and induction of apoptosis in renal cell carcinoma

Human beta-defensin-1 (hBD-1) is a candidate tumor suppressor gene located on chromosome 8p23. Previously, we showed that cancer-specific loss of hBD-1 was found in 90% of renal clear cell carcinomas and in 82% of prostate cancers. To investigate the possible mechanisms of decreased gene expression and determine the function of hBD-1 protein in urological cancers, we sequenced hBD-1 gene coding regions in prostatic and renal cancer samples. We then analyzed the frequency distribution of promoter polymorphisms and determined the effect of these base changes on transcriptional activity of the hBD-1 promoter. A polymorphism at -688 bases upstream of the ATG start codon affects hBD-1 promoter activity, leading to a rate of reporter gene transcription that is 40% to 50% lower than the wild-type sequence when tested in either DU145 or TSU-Pr1 cell lines. In addition, a polymorphism at -44 bases was shown to enhance transcription up to 2.3 times more than the wild-type sequence in the same cell lines. In addition, three novel hBD-1 promoter mutations were found in renal and prostate cancer clinical samples. An iso-5-aza-2'-deoxycytidine treatment was effective in transcription up-regulation in DU145, suggesting a possible upstream methylation-dependent effect. Synthetic hBD-1 peptide inhibited bladder cancer cell TSU-Pr1 proliferation. Overexpression of the hBD-1 gene in renal cancer cells SW156 resulted in caspase-3-mediated apoptosis. These data support the hypothesis that hBD-1 is a potential tumor suppressor gene for urological cancers. Promoter point mutations may be responsible for cancer-specific loss of hDB-1 expression.

State-dependent inhibition of cystic fibrosis transmembrane conductance regulator chloride channels by a novel peptide toxin

Peptide toxins from animal venom have been used for many years for the identification and study of cation-permeable ion channels. However, no peptide toxins have been identified that interact with known anion-selective channels, including cystic fibrosis transmembrane conductance regulator (CFTR), the protein defective in cystic fibrosis and a member of the ABC transporter superfamily. Here, we describe the identification and initial characterization of a novel 3.7-kDa peptide toxin, GaTx1, which is a potent and reversible inhibitor of CFTR, acting from the cytoplasmic side of the membrane. Thus, GaTx1 is the first peptide toxin identified that inhibits a chloride channel of known molecular identity. GaTx1 exhibited high specificity, showing no effect on a panel of nine transport proteins, including Cl(-) and K(+) channels, and ABC transporters. GaTx1-mediated inhibition of CFTR channel activity is strongly state-dependent; both potency and efficacy are reduced under conditions of elevated [ATP], suggesting that GaTx1 may function as a non-competitive inhibitor of ATP-dependent channel gating. This tool will allow the application of new quantitative approaches to study CFTR structure and function, particularly with respect to the conformational changes that underlie transitions between open and closed states.

A fluorimetric method for determination of calcineurin activity

Calcineurin is a calcium-dependent, serine/threonine phosphatase that is involved in a variety of signaling pathways. Calcineurin is distinct among phosphatases because its activity requires calcium and is not sensitive to inhibition by compounds that block the related phosphatases PP1A and PP2A. Therefore, the most common methods to measure calcineurin activity rely on calcium-dependent dephosphorylation of a substrate derived from the RII subunit of protein kinase A in the presence of PP1A/PP2A inhibitors. However, current techniques quantify activity by measurement of released radioactive phosphate or detection of free phosphate with malachite green. Both methods involve technical challenges and have undesirable features. We report a new calcineurin fluorimetric assay that utilizes a fluorescently labeled phosphopeptide substrate and separation of dephosphorylated peptide product by titanium-oxide. The method is rapid, quantitative, involves no radioactivity and is suitable for high throughput assays. Furthermore, with the use of a standard curve, precise measurements of calcineurin activity can be obtained.

Comparison of computed virtual chromoendoscopy and conventional chromoendoscopy with acetic acid for detection of neoplasia in Barrett's esophagus

BACKGROUND AND STUDY AIMS

Computed virtual chromoendoscopy (CVC) is a new imaging technique that enhances mucosal surface contrast and highlights the vascular pattern without the need for dye-spraying as in conventional chromoendoscopy. The aim of this prospective randomized pilot study with a crossover design was to compare CVC with conventional chromoendoscopy with acetic acid (CAA) for the detection of high grade intraepithelial neoplasia (HGIN) or early cancer in patients with Barrett's esophagus.

PATIENTS AND METHODS

57 patients with Barrett's esophagus (mean length 3.8 cm) and a history of HGIN/early cancer or suspected HGIN/early cancer were randomly allocated to undergo either CAA or CVC. All patients were re-examined with the alternative procedure at 4 - 6 weeks after the initial endoscopy. The two procedures were performed by five endoscopists, who were blinded to the findings of the other examination. At each examination, targeted biopsies were taken from all detected lesions, followed by random four-quadrant biopsies.

RESULTS

In 24/57 patients, 30 lesions with HGIN/early cancer were detected. The sensitivity of targeted biopsies for HGIN/early cancer on a 'per lesion' basis was 87 % (26/30) for both CAA and CVC. The positive predictive value was 39 % (26/66) for CAA and 37 % (26/70) for CVC. In the 'per patient' analysis, sensitivity was 83 % (20/24) and 92 % (22/24) for CAA and CVC, respectively ( P = 0.617). Stepwise random four-quadrant biopsies identified only one patient with HGIN/early cancer that was missed by both, CAA and CVC.

CONCLUSIONS

Computed virtual chromoendoscopy is a helpful adjunct for surveillance of Barrett's esophagus and appears to be as accurate as conventional chromoendoscopy in the detection of HGIN/early cancer.

Comparison of computed virtual chromoendoscopy and conventional chromoendoscopy with acetic acid for detection of neoplasia in Barrett's esophagus

BACKGROUND AND STUDY AIMS

Computed virtual chromoendoscopy (CVC) is a new imaging technique that enhances mucosal surface contrast and highlights the vascular pattern without the need for dye-spraying as in conventional chromoendoscopy. The aim of this prospective randomized pilot study with a crossover design was to compare CVC with conventional chromoendoscopy with acetic acid (CAA) for the detection of high grade intraepithelial neoplasia (HGIN) or early cancer in patients with Barrett's esophagus.

PATIENTS AND METHODS

57 patients with Barrett's esophagus (mean length 3.8 cm) and a history of HGIN/early cancer or suspected HGIN/early cancer were randomly allocated to undergo either CAA or CVC. All patients were re-examined with the alternative procedure at 4 - 6 weeks after the initial endoscopy. The two procedures were performed by five endoscopists, who were blinded to the findings of the other examination. At each examination, targeted biopsies were taken from all detected lesions, followed by random four-quadrant biopsies.

RESULTS

In 24/57 patients, 30 lesions with HGIN/early cancer were detected. The sensitivity of targeted biopsies for HGIN/early cancer on a 'per lesion' basis was 87 % (26/30) for both CAA and CVC. The positive predictive value was 39 % (26/66) for CAA and 37 % (26/70) for CVC. In the 'per patient' analysis, sensitivity was 83 % (20/24) and 92 % (22/24) for CAA and CVC, respectively ( P = 0.617). Stepwise random four-quadrant biopsies identified only one patient with HGIN/early cancer that was missed by both, CAA and CVC.

CONCLUSIONS

Computed virtual chromoendoscopy is a helpful adjunct for surveillance of Barrett's esophagus and appears to be as accurate as conventional chromoendoscopy in the detection of HGIN/early cancer.

Alterations in cytoskeletal and immune function-related proteome profiles in whole rat lung following intratracheal instillation of heparin

Background

Heparin has been shown to modify fundamental biologic processes ranging from blood coagulation and cell proliferation to fibrogenesis and asthma. The goal of this study was to identify specific or broad biologic responses of the rat lung to intratracheal instillation of heparin by targeted proteomic analysis.

Methods

Rats were given either aerosolized 500 μg heparin in 250 μl saline or saline alone. Lungs were harvested at 0, 24, or 96 hours post-treatment and isolated proteins analyzed by two-dimensional gel electrophoresis. Proteins which increased and decreased significantly in treated groups above controls were then selected for identification by mass spectrometry.

Results

Although heparin treatments resulted in a general reduction in cytosolic protein expression, there were significant increases within members of discrete groups of proteins. At 24 hours, proteins which function in cytoskeletal organization and in calcium signaling were up-regulated between 2- and 27-fold above baseline and untreated controls. Increased proteins include annexins V and VI, septin 2, capping G protein, actin-related protein 3, moesin, RhoGDP dissociation inhibitor, and calcyclin. A group of proteins relating to immune response and tumor suppressor function were either up-regulated (tumor suppressor p30/hyaluronic acid binding protein-1, Parkinson disease protein 7, proteosome 28 subunit/interferon-γ inducible protein, and proteosome subunit macropain α-1) or strongly down-regulated (transgelin). At 96 hours, most proteins that had increased at 24 hours remained elevated but to a much lesser degree.

Conclusion

These cumulative observations demonstrate that whole lung heparin treatment results in significant up-regulation of selected groups of proteins, primarily those related to cytoskeletal reorganization and immune function, which may prove to be relevant biomarkers useful in analysis of lung exposures/treatments as well as in system biology studies.

Menstrual hemocidin HbB115-146 is an acidophilic antibacterial peptide potentiating the activity of human defensins, cathelicidin and lysozyme

PROBLEM

Our recent studies proved that menstrual discharge is exceptionally rich in bactericidal hemoglobin peptides (hemocidins). Of special interest is the behavior of hemocidins in low pH of the vagina, in different ionic strengths, and in the presence of other specialized antibacterial molecules acting in this organ.

METHODS OF STUDY

We studied the activity of a model representative of menstrual hemocidin: the peptide from human beta-globin, spanning residues 115-146 (HbB115-146). The bactericidal action of this peptide in different physicochemical conditions, as well as the evaluation of the synergistic effect of the peptide with mixtures of neutrophil alpha-defensin HNP-1, epithelial beta-defensin HBD-1, cathelicidin LL-37 and lysozyme were studied using the bacterial membrane permeability test.

RESULTS

The HbB115-146 is a salt-resistant antibiotic molecule strongly potentiating its activity in acidic conditions (pH 4.4-5.0), characteristic for the vagina. Hemocidin HbB115-146 is also an effective factor stimulating the activity of other antibacterial polypeptides present in the female urogenital tract. The observed synergistic effect is preserved or enhanced at lower pH and, with the exception of HBD-1, is observed also at physiological salt concentrations.

CONCLUSION

The results of this study clearly demonstrate that hemocidins are important polypeptide factors involved in maintaining vaginal immunity during normal menstrual bleedings.

Proteomic identification of biomarkers in the cerebrospinal fluid (CSF) of astrocytoma patients

The monitoring of changes in the protein composition of the cerebrospinal fluid (CSF) can be used as a sensitive indicator of central nervous system (CNS) pathology, yet its systematic application to analysis of CNS neoplasia has been limited. There is a pressing need for both a better understanding of gliomagenesis and the development of reliable biomarkers of the disease. In this report, we used two proteomic techniques, two-dimensional gel electrophoresis (2-DE), and cleavable Isotope-Coded Affinity Tag (cICAT) to compare CSF proteomes to identify tumor- and grade-specific biomarkers in patients bearing brain tumors of differing histologies and grades. Retrospective analyses were performed on 60 samples derived from astrocytomas WHO grade II, III, and IV, schwannomas, metastastic brain tumors, inflammatory samples, and non-neoplastic controls. We identified 103 potential tumor-specific markers of which 20 were high-grade astrocytoma-specific. These investigations allowed us to identify a spectrum of signature proteins that could be used to distinguish CSF derived from control patients versus those with low- (AII) or high-grade (AIV) astrocytoma. These proteins may represent new diagnostic, prognostic, and disease follow-up markers when used alone or in combination. These candidate biomarkers may also have functional properties that play a critical role in the development and malignant progression of human astrocytomas, thus possibly representing novel therapeutic targets for this highly lethal disease.

Proteomic analysis of cerebrospinal fluid discriminates malignant and nonmalignant disease of the central nervous system and identifies specific protein markers

CNS diseases are often accompanied by changes in the protein composition of cerebrospinal fluid (CSF). SELDI-TOF-MS provides an approach for identifying specific protein markers of disease in biological fluids. We compared the CSF proteomes from patients with neoplastic and reactive/inflammatory CNS diseases to identify potential biomarkers. SELDI-TOF-MS was performed on CSF derived from lumbar puncture of 32 patients, including 10 with CNS malignancies, 12 with inflammatory or reactive conditions, and 10 with unknown CNS disease. Using the SAX-2 (strong anionic exchange) chip, we uncovered three conserved protein peak ranges within each disease category. For neoplastic diseases, we identified conserved peaks at 7.5-8.0 kDa (9/10 samples), 15.1-15.9 kDa (8/10 samples), and 30.0-32.0 kDa (5/10 samples). In reactive/inflammatory diseases, conserved peaks were found at 6.7-7.1 kDa (10/12 samples), 11.5-11.9 kDa (12/12 samples), and 13.3-13.7 kDa (9/12 samples). A protein from the 30.0 to 32.0 kDa peak range found in neoplastic CSF was identified by MALDI analysis as carbonic anhydrase, a protein overexpressed in many malignancies including high-grade gliomas. Similarly, cystatin C was identified in the 13.3-13.7 kDa peak range in non-neoplastic CSF and was most prominent in inflammatory conditions. Our approach provides a rational basis for identifying biomarkers that could be used for detection, diagnosis, and monitoring of CNS diseases.

Identification of three novel peptides isolated from the venom of the neotropical social waspPolistes major major

Three novel peptides designated as PMM1, PMM2, and PMM3 were isolated and characterized from the venom of the social wasp Polistes major major, one of the most common wasps in the Dominican Republic. By Edman degradation, and MALDI-TOF and ESI-QTOF mass spectrometry, the primary sequences of these peptides were established as follows: PMM1, H-Lys-Arg-Arg-Pro-Pro-Gly-Phe-Thr-Pro-Phe-Arg-OH (1357.77 Da); PMM2, H-Ile-Asn-Trp-Lys-Lys-Ile-Ala-Ser-Ile-Gly-Lys-Glu-Val-Leu-Lys-Ala-Leu-NH2 (1909.19 Da); and PMM3, H-Phe-Leu-Ser-Ala-Leu-Leu-Gly-Met-Leu-Lys-Asn-Leu-NH2 (1317.78 Da). The suggested sequences were confirmed by MS analysis of peptide fragments obtained by enzymatic digestion. The peptide PMM1 is a lysyl-arginyl-Thr(6)-bradykinine that belongs to the wasp kinins group. The sequence of the PMM2 peptide is unique; it resembles somewhat the tetradecapeptide amides of the mastoparan group; however, the chain is extended by three additional amino acid residues. The sequence of PMM3 dodecapeptide is homologous to the peptides of the wasp chemotactic group.

Computed virtual chromoendoscopy: a new tool for enhancing tissue surface structures

We conducted a study of a newly developed "computed virtual chromoendoscopy" (CVC) system that enhances the contrast of the mucosal surface without the use of dyes. The CVC imaging technique is based on narrowing the bandwidth of the conventional endoscopic image arithmetically, using spectral estimation technology. Preliminary clinical tests comparing CVC-enhanced visualization of neoplastic and non-neoplastic lesions with images obtained by conventional endoscopy show that CVC enhances the vascular network as well as the pit pattern. CVC might therefore complement high-resolution endoscopy by facilitating the assessment of the nature and extent of gastrointestinal mucosal lesions.

ABRF ESRG 2005 study: identification of seven modified amino acids by Edman sequencing

Identification of modified amino acids can be a challenging part for Edman degradation sequence analysis, largely because they are not included among the commonly used phenylthiohydantion amino acid standards. Yet many can have unique retention times and can be assigned by an experienced researcher or through the use of a guide showing their typical chromatography characteristics. The Edman Sequencing Research Group (ESRG) 2005 study is a continuation of the 2004 study, in which the participating laboratories were provided a synthetic peptide and asked to identify the modified amino acids present in the sequence. The study sample provided an opportunity to sequence a peptide containing a variety of modified amino acids and note their retention times relative to the common amino acids. It also allowed the ESRG to compile the chromatographic properties and intensities from multiple instruments and tabulate an average elution position for these modified amino acids on commonly used instruments. Participating laboratories were given 2000 pmoles of a synthetic peptide, 18 amino acids long, containing the following modified amino acids: dimethyl- and trimethyl-lysine, 3-methyl-histidine, N-carbamyl-lysine, cystine, N-methyl-alanine, and isoaspartic acid. The modified amino acids were interspersed with standard amino acids to help in the assessment of initial and repetitive yields. In addition to filling in an assignment sheet, which included retention times and peak areas, participants were asked to provide specific details about the parameters used for the sequencing run. References for some of the modified amino acid elution characteristics were provided and the participants had the option of viewing a list of the modified amino acids present in the peptide at the ESRG Web site. The ABRF ESRG 2005 sample is the seventeenth in a series of studies designed to aid laboratories in evaluating their abilities to obtain and interpret amino acid sequence data.

Proteomic identification of the wt-p53-regulated tumor cell secretome

Tumor-stroma interactions play a major role in tumor development, maintenance and progression. Yet little is known on how the genetic alterations that underlie cell transformation elicit cell extrinsic changes modulating heterotypic cell interactions. We hypothesized that these events involve a modification in the complement of secreted proteins by the cell, acting as mediators of intercellular communication. To test this hypothesis, we examined the role of wt-p53, a major tumor suppressor, on the tumor microenvironment through its regulation of secreted factors. Using a combination of 2-DE and cICAT proteomic techniques, we found a total of 111 secreted proteins, 39 of which showed enhanced and 21 inhibited secretion in response to wt-p53 expression. The majority of these were not direct targets of p53 transcription factor activity, suggesting a novel role for wt-p53 in the control of intracellular protein trafficking and/or secreted protein stability. Evidence for p53-controlled post-translational modifications on nine secreted proteins was also found. These findings will enhance our understanding of wt-p53 modulated interactions of the tumor with its environment.

beta2-microglobulin is a signaling and growth-promoting factor for human prostate cancer bone metastasis

The protein factor beta2-microglobulin (beta2M), purified from the conditioned medium of human prostate cancer cell lines, stimulated growth and enhanced osteocalcin (OC) and bone sialoprotein (BSP) gene expression in human prostate cancer cells by activating a cyclic AMP (cAMP)-dependent protein kinase A signaling pathway. When beta2M was overexpressed in prostate cancer cells, it induced explosive tumor growth in mouse bone through increased phosphorylated cAMP-responsive element binding protein (CREB) and activated CREB target gene expression, including OC, BSP, cyclin A, cyclin D1, and vascular endothelial growth factor. Interrupting the beta2M downstream signaling pathway by injection of the beta2M small interfering RNA liposome complex produced an effective regression of previously established prostate tumors in mouse bone through increased apoptosis as shown by immunohistochemistry and activation of caspase-9, caspase-3, and cleavage of poly(ADP-ribose) polymerase. These results suggest that beta2M signaling is an attractive new therapeutic target for the treatment of lethal prostate cancer bone metastasis.

Comparison of amino acid compositions of peptides eluted from HLA-B27 molecules of healthy individuals and patients with ankylosing spondylitis

HLA-B27 is a relative risk factor for ankylosing spondylitis (AS) and is present in about 10% in European populations but in 95% of AS patients. Various data suggest that the HLA-B27 molecule itself could be the strongest risk factor, but there is no explanation for this association. To define differential antigen presenting features of HLA-B27 in healthy individuals and AS patients, a question that cannot be addressed by biochemical studies on cell lines, the HLA-B27 protein was purified from peripheral blood lymphocytes of AS patients and healthy controls and pool sequencing of the bound peptides was performed. Results show that peptides are rich in proline (Pro) and the content of arginine (Arg) is much lower in comparison with sequences listed in the register of peptides eluted from cell cultures. Statistically significant differences were detected in frequencies of a subset of amino acids, predominantly at positions in the middle of the peptides. The frequency of Glu was increased and Gln was decreased in peptides from AS patients. Detailed analysis of purity of the immunoisolated HLA molecules excluded that the peptides might originate from any co-purified HLA molecules other than B27. We conclude that statistically significant increase in the Glu/Gln ratio of peptides from AS patients, consistent with increased deamidation in vivo, may account for differential antigenicity of HLA-B27 in patients. Source protein(s) of deamidated peptides remain unknown.

Cationic polypeptides are required for anti-HIV-1 activity of human vaginal fluid

Mucosal surfaces of the vagina are the portals for heterosexual transmission of HIV-1 and therefore play a fundamental role in the pathogenesis of primary infection. In the search for direct biological evidence for the role of human vaginal fluid in innate host defense, we characterized the anti-HIV-1 function of cationic polypeptides within minimally manipulated vaginal fluid. In the current study we revealed that vaginal fluid confers intrinsic anti-HIV-1 properties against both X4 and R5 strains of HIV-1 and could protect against HIV-1 infection and reduce proviral genome integration in organotypic cultures of human cervicovaginal tissue. The majority of this activity was contained in the cationic polypeptide fraction, and the depletion of cationic polypeptides using a selective cation exchange resin ablated most of the intrinsic activity against HIV-1. By adding the cationic polypeptide fraction to depleted vaginal fluid, we were able to restore activity against HIV-1. Using a proteomic approach, we identified 18 cationic polypeptides within vaginal fluid, nearly all of which are either known antimicrobials or have other purported roles in host defense. Interestingly, physiologic concentrations of 13 of the cationic polypeptides were not active alone against HIV-1, yet in concert they partially restored the anti-HIV-1 activity of cation-depleted vaginal fluid. These results suggest that synergism between cationic polypeptides is complex, and full anti-HIV-1 activity probably involves the aggregate of the cationic peptides and proteins in vaginal fluid.

Distinct proteomic profiles of amphetamine self-administration transitional states

In the rat, continuous access to d-amphetamine (d-AMPH) leads to lengthy bouts of self-administration, voluntary abstinence, and relapse to self-administration. Previous studies have revealed that the progression from psychostimulant self-administration to abstinence to relapse is mediated in part by the ventral hippocampus. Stimulation of the ventral subiculum (vSub) during voluntary abstinence from d-AMPH self-administration reinstates self-administration and increases nucleus accumbens (NAc) dopamine efflux. Quantitative proteomic examination of the hippocampus from rats naive to amphetamine, during a self-administration session 'Binge', during voluntarily abstinence 'Abstinent', and after reinstatement of self-administration 'Relapse', revealed a differential proteomic state during abstinence. Actin- and cytoskeletal-related proteins were over-represented in the changes occurring during abstinence and suggest a decrease in actin filament polymerization. These changes may underlie alterations in neuronal tone during abstinence that could affect both neurotransmission and behavior. These data provide the first classification of addiction-related behaviors based on clustering of quantitative proteomic measurements. .

Chimeric epitopes delivered by polymeric synthetic linear peptides induce protective immunity to malaria

Polymeric linear peptide chimeras (LPCs) that incorporate Plasmodium vivax promiscuous T cell epitopes and the P. falciparum circumsporozoite protein B cell epitope have been shown to induce a high level of immunogenicity and overcome genetic restriction when tested as vaccine immunogens in BALB/c mice. The present study evaluates the biological relevance of several LPCs using a well characterized rodent malaria model. Polymeric peptide constructs based on P. berghei and P. yoelii sequences, and orthologous to the human malaria sequences included in the original LPCs, were designed and tested for immunogenicity in mice of different H-2 haplotypes. We demonstrate that robust immune responses are induced and that peptides containing the orthologous rodent Plasmodium sequences exhibited similar immunogenic capabilities. Unique to this report, we show that LPCs can also prime MHC class I-restricted cytotoxic T lymphocytes (CTLs) and, most relevantly, that a peptide construct prototype incorporating single B, T and CTL epitopes induced protection against an experimental challenge with P. berghei or P. yoelii sporozoites. Collectively, these results suggest that polymeric polypeptide chimeras can be used as a platform to deliver subunit vaccines.

Cytologic findings and protein expression profiles associated with ductal carcinoma of the breast in ductal lavage specimens using surface-enhanced laser desorption and ionization-time of flight mass spectrometry

BACKGROUND

Early detection of breast carcinoma enhances the chances for patient survival. The authors' work focused on an innovative technique that couples breast ductal lavage (DL) with surface-enhanced laser desorption and ionization-time of flight mass spectrometry (SELDI-TOF MS) to yield a highly sensitive and specific method of breast carcinoma detection.

METHODS

The study group included 16 women who had unilateral, biopsy-proven breast carcinoma. Studying paired DL specimens from each woman (the breast with and the breast without carcinoma), a cytologic investigation was performed on the cells present in the DL samples, and the protein content of the DL fluid was analyzed with the SELDI-TOF MS technique using the strong anionic exchange chip surface.

RESULTS

Only 5 of 16 DL specimens (31%) from breasts with biopsy-proven carcinoma contained malignant cells, whereas the remaining samples contained only histiocytes and clusters of benign ductal epithelium. In contrast, 12 of 16 DL specimens (75%) from breasts that contained carcinoma had a different protein peak pattern compared with the paired DL specimen from the same patient's contralateral, uninvolved breast. This finding was independent of the presence of neoplastic cells in the lavage fluid. In addition, specific protein peaks, which may represent potential biomarkers, were identified in the DL fluids from breasts with carcinoma. Some of these peaks were conserved between different patients.

CONCLUSIONS

The combination of breast DL with SELDI-TOF MS offers a unique and powerful technique for the detection and monitoring of breast carcinoma. This method has the potential to enhance the diagnostic utility of conventional DL cytology.

Cytochrome c oxidase subunit IV as a marker of protein kinase Cepsilon function in neonatal cardiac myocytes: implications for cytochrome c oxidase activity

We have previously demonstrated that low concentrations of phorbol esters stimulate the selective translocation of protein kinase C (PKC) alpha and epsilon from the cell soluble to the particulate fraction in NCMs (neonatal rat cardiac myocytes). We therefore determined if the in vitro phosphorylation of substrates in these fractions could be used as assays of PKCalpha or epsilon activation. Intact cell phorbol ester treatment caused a decline in the in vitro (32)P-incorporation into several proteins in the cell-soluble fraction. These declines occurred in the presence or absence of in vitro Ca(2+) and probably reflected the exit of PKC isoenzymes from the soluble fraction. In contrast, an approx. 18 kDa protein incorporated (32)P in particulate fractions isolated from 4beta-PMA-treated cells in a Ca(2+)-independent manner. Proteomic and immunoprecipitation analyses indicated that the protein is subunit IV of the cytochrome c oxidase complex (COIV). In vitro phosphorylation of COIV was attenuated by PKC pseudosubstrate peptides. Introduction of an PKCepsilon-selective translocation inhibitor [Johnson, Gray, Chen and Mochly-Rosen (1996) J. Biol. Chem. 271, 24962-24966] into NCMs before 4beta-PMA treatments also attenuated the in vitro phosphorylation of COIV. In mitochondrial extracts from 4beta-PMA-treated NCMs, the PKCepsilon isoenzyme coimmunoprecipitated with COIV, and cytochrome c oxidase activity was enhanced 2-fold. The in vitro phosphorylation of COIV reflects a novel approach for monitoring PKCepsilon function in NCMs. Furthermore, PKCepsilon probably interacts with COIV in NCM mitochondria to enhance electron-transport chain complex IV activity.

Severe rhabdomyolysis and renal failure triggered by a sauna visit in sickle cell trait: a case report

Sickle cell trait (SCT) is an usually asymptomatic hemoglobinopathy. Cases of sudden excertional deaths in individuals with SCT have been described. We here report an exceptional case of excessive rhabdomyolysis and acute renal failure triggered by a sauna visit in a 29 year-old African American with SCT.

Degradation of human antimicrobial peptide LL-37 by Staphylococcus aureus-derived proteinases

Cathelicidin LL-37 is one of the few human bactericidal peptides with potent antistaphylococcal activity. In this study we examined the susceptibility of LL-37 to proteolytic degradation by two major proteinases produced by Staphylococcus aureus, a metalloproteinase (aureolysin) and a glutamylendopeptidase (V8 protease). We found that aureolysin cleaved and inactivated LL-37 in a time- and concentration-dependent manner. Analysis of the generated fragments by mass spectroscopy revealed that the initial cleavage of LL-37 by aureolysin occurred between the Arg19-Ile20, Arg23-Ile24, and Leu31-Val32 peptide bonds, instantly annihilating the antibacterial activity of LL-37. In contrast, the V8 proteinase hydrolyzed efficiently only the Glu16-Phe17 peptide bond, rendering the C-terminal fragment refractory to further degradation. This fragment (termed LL-17-37) displayed antibacterial activity against S. aureus at a molar level similar to that of the full-length LL-37 peptide, indicating that the antibacterial activity of LL-37 resides in the C-terminal region. In keeping with LL-37 degradation by aureolysin, S. aureus strains that produce significant amounts of this metalloprotease were found to be less susceptible to LL-17-37 than strains expressing no aureolysin activity. Taken together, these data suggest that aureolysin production by S. aureus contributes to the resistance of this pathogen to the innate immune system of humans mediated by LL-37.

Phosphoregulation of mixed-lineage kinase 1 activity by multiple phosphorylation in the activation loop

Mixed-lineage kinase 1 (MLK1) is a mitogen-activated protein kinase kinase kinase capable of activating the c-Jun NH(2)-terminal kinase (JNK) pathway. Full-length MLK1 has 1104 amino acids and a domain structure identical to MLK2 and MLK3. Immunoblot and mass spectrometry show that MLK1 is threonine (and possibly serine) phosphorylated in or near the activation loop. A kinase-dead mutant is not, consistent with autophosphorylation. Mutation to alanine of any of the four serine or threonine residues in the activation loop reduces both the activity of the recombinant kinase domain and JNK pathway activation driven by full-length MLK1 expressed in mammalian cells. Furthermore, the gel mobility of the mutant MLK1s is closer to that of the kinase-dead than wild type, consistent with reduced phosphorylation. Thr312 is the key residue: MLK1[T312A] retains only basal activity (about 1-2% of wild type), and its gel mobility is indistinguishable from kinase-dead. Thr312 does not suffice, however; phosphorylation of multiple sites is necessary for full activation of MLK1. An activation mechanism consistent with these data involves phosphorylation of multiple sites in the activation loop, with phosphorylation of Thr312 required for full phosphorylation. This mechanism is broadly similar to that previously reported for MLK3 [Leung, I. W., and Lassam, N. (2001) J. Biol. Chem. 276, 1961-1967], but the key residue differs.

Purification and characterization of two forms of endo-?-1,4-mannanase from a thermotolerant fungus, IMI 385708 (formerly IMI 158749)

Two extracellular endo-beta-1,4-mannanases, MAN I (major form) and MAN II (minor form), were purified to electrophoretic homogeneity from a locust bean gum-spent culture fluid of Aspergillus fumigatus IMI 385708 (formerly Thermomyces lanuginosus IMI 158749). Molecular weights of MAN I and MAN II estimated by SDS-PAGE were 60 and 63 kDa, respectively. IEF afforded several glycoprotein bands with pI values in the range of 4.9-5.2 for MAN I and 4.75-4.9 for MAN II, each exhibiting enzyme activity. MAN I as well as MAN II showed highest activity at pH 4.5 and 60 degrees C and were stable in the pH range 4.5-8.5 and up to 55 degrees C. In accordance with the ability of the enzymes to catalyze transglycosylation reactions, 1H NMR spectroscopy of reaction products generated from mannopentaitol confirmed the retaining character of both enzymes. Both MAN I and MAN II exhibited essentially identical kinetic parameters for polysaccharides and a similar hydrolysis pattern of various oligomeric and polymeric substrates. Both beta-mannanases contained identical internal amino acid sequence corresponding to glycoside hydrolase family 5 and also a cellulose-binding module. These data suggested that both MAN I and MAN II are products of the same gene differing in posttranslational modification. Indeed, the corresponding gene was identified within the recently sequenced Aspergillus fumigatus genome (http://sanger.ac.uk/Projects/A_fumigatus/).