A simple enzyme-linked immunosorbent assay (ELISA) for the neuron-specific gamma isozyme of human enolase (NSE) using monoclonal antibodies raised against synthetic peptides corresponding to isozyme sequence differences

Highly sensitive photoelectrochemical neuron specific enolase analysis based on cerium and silver Co-Doped Sb2WO6

A signal-enhanced photoelectrochemical immunoassay technique for detecting neuron specific enolase (NSE) was proposed. As a photoactive matrix, (Ce,Ag):Sb₂WO₆ was firstly investigated via doping Ce and Ag into Sb₂WO₆. It could be found that the presence of Ce and Ag not only had enormous variation on the morphology of Sb₂WO₆, but also showed excellent PEC behavior. In order to further improve the visible light utilization rate of (Ce,Ag):Sb₂WO₆, In₂S₃ was modified onto the surface of (Ce,Ag):Sb₂WO₆ to enhance visible light absorption. In addition, the CdS/PDA was served as a secondary antibody marker to further amplify signal. Especially, PDA as an electron donor could effectively remove photogenerated holes. Meanwhile, the good matching cascade band-edge levels between CdS and Sb₂WO₆ could promote photoelectron migration, improve the PEC response, and achieve sensitive detection of NSE. Under the selected excellent conditions, the photocurrent can linearly increase with the increase of NSE concentration in the operating range from 0.1 pg/mL to 50 ng/mL, and the limit of detection is 1.57 fg/mL. The constructed immunosensor also exhibits satisfactory stability, selectivity, and reproducibility, and it creates conditions for the detection of other biomolecules.

The differential expression of omega-3 and omega-6 fatty acid metabolising enzymes in colorectal cancer and its prognostic significance

Background:

Colorectal cancer is a common malignancy and one of the leading causes of cancer-related deaths. The metabolism of omega fatty acids has been implicated in tumour growth and metastasis.

Methods:

This study has characterised the expression of omega fatty acid metabolising enzymes CYP4A11, CYP4F11, CYP4V2 and CYP4Z1 using monoclonal antibodies we have developed. Immunohistochemistry was performed on a tissue microarray containing 650 primary colorectal cancers, 285 lymph node metastasis and 50 normal colonic mucosa.

Results:

The differential expression of CYP4A11 and CYP4F11 showed a strong association with survival in both the whole patient cohort (hazard ratio (HR)=1.203, 95% CI=1.092–1.324, χ²=14.968, P=0.001) and in mismatch repair-proficient tumours (HR=1.276, 95% CI=1.095–1.488, χ²=9.988, P=0.007). Multivariate analysis revealed that the differential expression of CYP4A11 and CYP4F11 was independently prognostic in both the whole patient cohort (P=0.019) and in mismatch repair proficient tumours (P=0.046).

Conclusions:

A significant and independent association has been identified between overall survival and the differential expression of CYP4A11 and CYP4F11 in the whole patient cohort and in mismatch repair-proficient tumours.

Integrative analysis of the colorectal cancer proteome: potential clinical impact

INTRODUCTION

Colorectal cancer (CRC) is one of the common types of cancer that affects a significant proportion of the population and is a major contributor to cancer related mortality. The relatively poor survival rate of CRC could be improved through the identification of clinically useful biomarkers. Areas covered: This review highlights the need for biomarkers and discusses recent proteomics discoveries in the aspects of CRC clinical practice including diagnosis, prognosis, therapy, screening and molecular pathological epidemiology (MPE). Studies have been evaluated in relation to biomarker target, methodology, sample selection, limitations, and potential impact. Finally, the progress in proteomic approaches is briefly discussed and the main difficulties facing the translation of proteomics biomarkers into the clinical practice are highlighted. Expert commentary: The establishment of specific guidelines, best practice recommendations and the improvement in proteomic strategies will significantly improve the prospects for developing clinically useful biomarkers.

Performance characteristics of seven neuron-specific enolase assays

BACKGROUND/AIMS

The determination of neuron-specific enolase (NSE) is relatively frequently requested in the differential diagnosis of small-cell lung carcinoma and non-small-cell lung carcinoma. The individual results of different immunoassays are often not comparable, which has been confirmed by long-term external quality assessments. In this study, we assessed the possible sources of these differences.

METHODS

More than 3,000 NSE analyses were performed using seven different immunoassays: DELFIA (PerkinElmer), Elecsys 2010 or Modular Analytics E 170 (Roche), Kryptor (B.R.A.H.M.S.), the enzyme-linked immunosorbent assay DRG and three assays based on immunoradiometric assays (DiaSorin, Immunotech and Schering-CIS). The following parameters were evaluated: precision profile of the individual methods, linearity on dilution and modified recovery, comparability and discrimination of immunoassays, sensitivity, and specificity.

RESULTS

There were differences in the correlation of values of certain low-concentration specimens. Some assays correlate well while others do not (up to fivefold difference), especially in the case of controls prepared synthetically. Therefore, the current non-standardized preparation of controls is questionable in our opinion. In the cutoff range, the difference in the results of native samples did not exceed its double value. The variation in values >100 microg/l obtained with different assays is <40%.

CONCLUSION

Our results confirmed expected matrix interferences especially in the range of normal and cutoff NSE concentrations. Another source of discrepancies can be attributed to different antibody affinity to alphagamma- and gammagamma-enolase isoenzymes. Finally, improper settings of cutoff values also contribute to the different discrimination of the methods.

Interferon-gamma-induced suppression of S100A4 transcription is mediated by the class II transactivator

We have previously shown that interferon-gamma (IFN-gamma) inhibits expression of the metastasis-promoting protein S100A4. In the present study, we further explore the mechanism behind the IFN-gamma-mediated effects on the human S100A4 promoter and demonstrate that IFN-gamma represses S100A4 promoter activity through induction of the class II transactivator (CIITA). The acidic domain in the N-terminal part of CIITA was crucial for the observed IFN-gamma-induced inhibition of S100A4 promoter activity, probably by binding the histone acetyltransferase CBP/p300. Importantly, overexpression of CIITA significantly reduced the expression of endogenous S100A4. Our data suggest a model where CIITA represses S100A4 transcription through sequestering of CBP/p300, thereby reducing the level of CBP/p300 at the S100A4 promoter, which in turn leads to inhibition of S100A4 transcription.

Immunohistochemical localization of cytochrome P450 CYP1B1 in breast cancer with monoclonal antibodies specific for CYP1B1

Cytochrome P450 CYP1B1 is a recently identified member of the CYP1 P450 family. We have shown that this P450 displays increased expression in several types of human cancer, indicating that CYP1B1 is a potential tumor biomarker. In this study we developed monoclonal antibodies (MAbs) to CYP1B1 that are effective on formalin-fixed, paraffin-embedded tissue sections and investigated the presence of CYP1B1 in a series of primary breast cancers. The MAbs were generated using a synthetic peptide coupled to carrier protein as the immunogen. The MAbs specifically recognized CYP1B1 and did not recognize either CYP1A1 or CYP1A2, related CYP1 forms. The MAbs were tested by immunohistochemistry and were found to be effective on formalin-fixed, paraffin-embedded tissue sections. The majority of breast cancers showed positive immunoreactivity for CYP1B1, and in each case CYP1B1 was specifically localized to tumor cells. The presence of CYP1B1 in breast cancer cells is likely to contribute to their metabolism of estradiol because CYP1B1 is a specific estradiol hydroxylase. (J Histochem Cytochem 47:1457-1464, 1999)

Matrix metalloproteinase-1 is associated with poor prognosis in oesophageal cancer

The matrix metalloproteinases (MMPs) are a family of closely related proteolytic enzymes which are involved in the degradation of different components of the extracellular matrix. There is increasing evidence to indicate that individual MMPs have an important role in tumour invasion and tumour spread. Monoclonal antibodies specific for MMP-1, MMP-2, or MMP-9 have been produced, using as immunogens peptides selected from the amino acid sequences of individual MMPs. The presence of MMP-1, MMP-2, and MMP-9 in oesophageal cancer was investigated by immunohistochemistry on formalin-fixed, wax-embedded sections of oesophageal cancers. The relationship of individual MMPs to prognosis and survival was determined. MMP-1 was present in 24 per cent of oesophageal cancers, while MMP-2 and MMP-9 were present in 78 and 70 per cent of tumours, respectively. The presence of MMP-1 was associated with a particularly poor prognosis (log rank test 8.46, P < 0.004) and was an independent prognostic factor (P = 0.02). The identification of individual MMPs in oesophageal cancer provides a rational basis for use in the treatment of oesophageal cancer of MMP inhibitors which are currently undergoing clinical trial.

Matrix metalloproteinase-1 is associated with poor prognosis in colorectal cancer

Colorectal cancer is one of the commonest malignant tumors and has a relatively poor prognosis. The outcome depends on the extent of local and particularly metastatic tumor spread. The matrix metalloproteinases (MMPs) are a family of closely related enzymes that degrade the extracellular matrix and are considered to be important in facilitating tumor invasion and spread (1-3). Using immunohistochemistry we have investigated the occurrence in colorectal cancer of MMP-1 (interstitial collagenase). Our monoclonal antibody was prepared against a synthetic peptide corresponding to an amino acid sequence specific for MMP-1 and was selected to react in formalin-fixed wax-embedded sections, thus allowing use in diagnostic histopathology and also enabling access to archival material. We found that the presence of MMP-1 in colorectal cancer is associated with a poor prognosis (P = 0.006) and has prognostic value independent of Dukes stage. One MMP inhibitor that strongly inhibits MMP-1 has already been shown to inhibit growth of human colon cancer xenografts in nude mice (4). Our results suggest that treatment of those individuals whose colon tumors produce MMP-1 with MMP inhibitors is a therapeutic strategy worth pursuing.

PC12 cells show immunoreactivity to a number of proteins and peptides, including vasostatin

N-terminal chromogranin A (CGA) contains peptides with vasoinhibitory properties, called vasostatin I (VST) and II [CGA (1-76) and (1-113) in human and bovine; (1-128) in rat]. Three fragments of VST were synthesized and antisera raised: human CGA (68-76) (VST I) rat CGA (121-128) (VST II fragment 2), and bovine/human CGA (83-91) (VST II, fragment 3). Strong immunoreactivity was observed in PC12 cells with antisera to VST II, fragment 3, VST I, and neuron-specific enolase. Little or no immunoreactivity was observed using antisera to synaptophysin, whole molecule CGA, pancreastatin, protein gene product 9.5, somatostatin, pancreatic polypeptide, or with antibodies 875 and 876 to VST II, fragment 2. Most of the VST antisera cross-reacted, with a species of molecular weight, 61 kDa but one, 874, cross-reacted with two species of molecular weights, 7.2 and 12 kDa. Our results show the presence of N-terminally processed CGA in PC12 cells.

Sensitive detection of hantaviruses by biotin-streptavidin enhanced immunoassays based on bank vole monoclonal antibodies

Antigen capture enzyme-linked immunosorbent assays (ELISAs) based on detection of the viral nucleocapsid protein (N) were designed for rapid diagnosis of hantavirus infections. Several combinations of bank vole (Clethrionomys glareolus) monoclonal antibodies with various N-epitope specificities were used for the development of two double-antibody sandwich forms of ELISA; PUU virus AG-ELISA for an exclusive detection of Puumala-related viruses, and Hantavirus AG-ELISA for a more extensive detection of all serotypes of hemorrhagic fever with renal syndrome (HFRS) viruses. The biotin-streptavidin system, in combination with horseradish peroxidase, rendered the assays' sensitivities similar to or even higher than immunoblotting. Calculated detection limits for the PUU virus and the Hantavirus AG-ELISAs were 405 and 50 focus forming units or 80 and 10 infected Vero E6 cells, respectively. The assays were evaluated and found to be suitable for convenient and routine detection of hantaviruses in cell cultures and in infected animal tissue.

Immunohistochemistry of neurone specific enolase with gamma subunit specific anti-peptide monoclonal antibodies

AIMS

To investigate the application in immunohistochemistry of gamma-subunit specific anti-peptide monoclonal antibodies to human neurone specific enolase (NSE); and to determine their reactivity with formalin fixed, wax embedded sections of normal tissue and neuroendocrine tumours.

METHODS

Immunohistochemical staining was performed on sections of formalin fixed, wax embedded tissue with two monoclonal antibodies (NSE-P1 and NSE-P2) raised against different synthetic peptides specific for the gamma subunit of human enolase (neurone specific enolase).

RESULTS

Both antibodies gave strong immunostaining in normal tissues and cells known to contain NSE. There was no immunoreactivity in tissues containing either the alpha alpha or beta beta isozymes of enolase. The reactivity of the antibodies with a range of neuroendocrine tumours was also studied and both antibodies gave strong immunostaining of tumour cells in the different tumours.

CONCLUSIONS

The use of synthetic peptides from defined regions of a molecule as immunogenes provides antibodies of high specificity. These monoclonal antibodies to NSE are ideally suited for immunohistochemical studies and they should be particularly useful in histopathology as they react with epitopes which are resistant to formalin fixation and wax embedding.