Until recently, the intrinsically high level of cross-talk between immune cells, the complexity of immune cell development, and the pleiotropic nature of cytokine signaling have hampered progress in understanding the mechanisms of immunosuppression by which tumor cells circumvent native and adaptive immune responses. One technology that has helped to shed light on this complex signaling network is the cytokine antibody array, which facilitates simultaneous screening of dozens to hundreds of secreted signal proteins in complex biological samples. The combined applications of traditional methods of molecular and cell biology with the high-content, high-throughput screening capabilities of cytokine antibody arrays and other multiplexed immunoassays have revealed a complex mechanism that involves multiple cytokine signals contributed not just by tumor cells but by stromal cells and a wide spectrum of immune cell types. This review will summarize the interactions among cancerous and immune cell types, as well as the key cytokine signals that are required for tumors to survive immunoediting in a dormant state or to grow and spread by escaping it. Additionally, it will present examples of how probing secreted cell-cell signal networks in the tumor microenvironment (TME) with cytokine screens have contributed to our current understanding of these processes and discuss the implications of this understanding to antitumor therapies.

Profiling protein expression on a global scale will have significant impact on biomedical research, particularly in the discovery and development of drugs and biomarkers. Through the years, several antibody array systems have been invented and developed for multiple protein detection. However, a reliable and high-content system for protein profiling from many biological samples has yet developed. To address this problem, we have developed a high density antibody array and used this technology to uncover the potential biomarkers of ovarian cancer. In this approach, biological samples are conjugated with biotin. Antibody arrays are then used to capture the biotinylated proteins. The presence of proteins captured by the antibody chip is detected using streptavidin-conjugated fluorescent dye (Cy3 equivalent) as a reporter. The signals, which are visualized by laser scanning, are normalized using positive, negative, and internal controls. Using this biotin-label-based antibody array technology, the expression levels of 507 human, 308 mouse, 90 rat target proteins can be simultaneously detected, including cytokines, chemokines, adipokines, growth factors, angiogenic factors, proteases, soluble receptors, soluble adhesion molecules, and other proteins in a variety of samples. Most proteins can be detected at pg/ml and ng/ml levels with a CV of less than 20%. Using human biotin-based antibody arrays, we screened the serum expression profiles of 507 proteins in 47 ovarian cancer patients and 39 normal subjects. A panel of protein expression showed significant difference between normal and cancer (P<0.05). By Classification Analysis and Split-Point Score Analysis of these two groups, a small group of proteins can be used to distinguish ovarian cancer patients from normal subjects and between ovarian cancer patients and normal subjects. Our results suggest the biotin label-based antibody arrays that we have developed have great potential in applications for biomarker discovery. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4625.

Allergy is inversely related to glioma risk. To determine whether prediagnostic allergy-related serum proteins are associated with glioma, we conducted a nested case-control study of seven cytokines (IL4, IL13, IL5, IL6, IL10, IFNG, TGFB2), two soluble cytokine receptors (sIL4RA, sIL13RA2) and three allergy-related transcription factors (FOXP3, STAT3, STAT6) using serum specimens from the Janus Serum Bank Cohort in Oslo, Norway. Blood donors subsequently diagnosed with glioma (n = 487) were matched to controls (n = 487) on age and date of blood draw and sex. We first estimated individual effects of the 12 serum proteins and then interactions between IL4 and IL13 and their receptors using conditional logistic regression. We next tested equality of case-control inter-correlations among the 12 serum proteins. We found that TGFB2 is inversely related to glioblastoma (Odds Ratio (OR) = 0.87, 95% Confidence Interval (CI)) = 0.76, 0.98). In addition, ≤ 5 years before diagnosis, we observed associations between IL4 (OR = 0.82, 95% CI = 0.66, 1.01), sIL4RA (OR = 0.80, 95% CI = 0.65, 1.00), their interaction (OR = 1.06, 95% CI = 1.01, 1.12) and glioblastoma. This interaction was apparent > 20 years before diagnosis (IL4-sIL4RA OR = 1.20, 95% CI = 1.05, 1.37). Findings for glioma were similar. Case correlations were different from control correlations stratified on time before diagnosis. Five years or less before diagnosis, correlations among case serum proteins were weaker than were those among controls. Our findings suggest that IL4 and sIL4RA reduce glioma risk long before diagnosis and early gliomagenesis affects circulating immune function proteins.

Many normal physiological and disease-related pathophysiological processes are regulated by the interactions of complex signaling networks of pro-and anti-inflammatory markers, growth factors, soluble receptors and extracellular matrix proteins, as well as other cell-cell signaling proteins, which we define collectively as cytokines. Because multiple cell-cell signaling factors may be involved in a single biological process, detection of expression of multiple cytokines is essential to unraveling the mechanisms and effects of many disease processes. Cytokine antibody arrays have been developed to meet this growing demand for multiplexed protein detection. In particular, discovery and validation of diseaserelated protein biomarkers require high-throughput detection of many proteins simultaneously. This review will address the complexity of cytokine biology, discuss current and future antibody array technologies and explore their applications in cytokine biomarker discovery and validation for variety of human diseases. Specific examples of these applications will be presented, including the search for cytokine biomarkers related to neurological and neurodegenerative diseases (such as autism and Alzheimer's), immunological disorders (including asthma), and various cancers.

Maple syrup urine disease (MSUD) is an autosomal recessive disorder caused by defective function of the mitochondrial branched chain alpha-ketoacid dehydrogenase (BCKD) complex. Mutations in both alleles of any of three genes for component proteins result in the clinical phenotype. Two discrete mutant alleles for the E1 beta subunit of the decarboxylase component in a proband with MSUD are defined and parental origin of each allele identified. The maternal mutation, an A to T transversion at nucleotide 526 in the coding sequence, potentiates an asparagine to tyrosine change at position 126 (N126Y). The paternal mutant allele contains a C to T transition at nucleotide 970 introducing a stop codon (R274 ). Western blot analysis revealed a 75% reduction in the E1 beta-N126Y protein and an absence of the R274* truncated protein in proband cells. Both mutant proteins could be synthesized, imported into mitochondria, and processed in vitro. Functional analysis of the mutant proteins provided new information on the role of E1 beta in the activity of BCKD. In vivo the E1 beta-N126Y protein associated into macromolecular complexes indistinguishable from those formed with the wild type E1 beta protein. However, catalytic activity of these complexes in proband cells was < 1% of wild type activity. Alignment comparisons with other thiamin pyrophosphate-requiring enzymes suggests the N126Y substitution could interfere with interactions of the protein with the cofactor causing inactivity. The truncated E1 beta-R274* protein is unstable and not found in mitochondria from the patient derived cells.