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// Mary Jo Fidler 1 , Casey Frankenberger 2 , Richard Seto 1 , Gabriela C. Lobato 3 , Cristina L. Fhied 2 , Selina Sayidine 2 , Sanjib Basu 4 , Mark Pool 2 , Reem Karmali 5, 6 , Marta Batus 1 , Wen-Rong Lie 7 , David Hayes 7 , Jehangir Mistry 7 , Philip Bonomi 1 and Jeffrey A. Borgia 2, 3 1 Section of Medical Oncology, Rush University Medical Center, Chicago, IL 60612, USA 2 Pathology, Rush University Medical Center, Chicago, IL 60612, USA 3 Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA 4 Preventative Medicine, Rush University Medical Center, Chicago, IL 60612, USA 5 Hematology, Oncology and Cell Therapy at Rush University Medical Center, Chicago, IL 60612, USA 6 Present address: Division of Hematology and Oncology, Northwestern University, Chicago, IL 60612, USA 7 EMD Millipore Corporation, St. Charles, MO 63304, USA Correspondence to: Jeffrey A. Borgia, email: Jeffrey_Borgia@Rush.edu Keywords: biomarker, non-small cell lung cancer (NSCLC), Luminex, erlotinib, epithelial-to-mesenchymal transition (EMT) Received: October 11, 2016 Accepted: February 06, 2017 Published: April 28, 2017 ABSTRACT Background: The objective of this study was to identify serum biomarkers capable of predicting clinical outcomes in previously-treated NSCLC patients with wild-type for EGFR activating mutations or insufficient tissue for mutation status determination. Methods: Sixty-six Luminex immunoassays representative of biological themes that emerged from a re-analysis of transcriptome data from the Cancer Genome Atlas (TCGA) were evaluate against pretreatment serum specimens from previously-treated advanced NSCLC patients received either cytotoxic chemotherapy (n=32) or erlotinib (n=79). Known EGFR mutation positive cases were excluded from analysis. Associations of biomarkers with outcome parameters and their differential interaction with treatment for survival outcomes were assessed using multivariate Cox PH analyses. Results: Our EMT-based transcriptomic analysis revealed a range of biological processes associated with angiogenesis, apoptosis, cachexia, inflammation, and metabolism emerging as those most highly associated with patient outcome. These processes were evaluated via surrogate serum biomarkers. A treatment-biomarker interaction analysis revealed that higher pretreatment levels of c-Met signaling biomarkers (i.e. HGF levels), pro-inflammatory/ pro-cachexia (e.g. IL-8, sIL-2Rα, FGF-2) processes and a pro-angiogenic (e.g. TGF-α, IL-8, VEGF) milieu were associated with inferior survival (HR=0.35, 0.29, 0.58, 0.50, 0.61, 0.45, respectively; all p

Biologics Higher Order Structure (HOS) is important to its safety and efficacy but difficult to define. A novel technology called Protein Conformational Array (PCA) was developed using antibody arrays to analyze monoclonal antibody Higher Order Structure. Protein Conformational Array (PCA) technology was developed based on the immunology epitope scanning principle. This technology offers systematic coverage toward the full amino acid sequence of the biologics with high sensitivity and accuracy. For the high volume analytical assays such as cell line selection, bioprocess and formulation development, more accurate and relatively high throughput methods will be more desirable. By using 34 different antibodies covering the whole mAb molecule and measuring the mAb surface epitope exposure, the mAb HOS can be precisely and systematically described. PCA is in two different formats, the ELISA format and magnetic beads-based Luminex format. The first few sections of this chapter will focus on the applications and findings from the ELISA-based PCA and the last two sections will discuss the Luminex system in elucidating detains of mAbs HOS under different stress conditions. Results will be discussed related to mAb HOS stability polymorphism, the multifaceted nature of the PCA technology and its applications in bioprocess and formulation development and comparability studies.

There is renewed interest in the Src family of protein tyrosine kinases (SFKs) as a result of their potential utility as molecular targets for cancer therapy. This protein family consists of 9 nonreceptor tyrosine kinases that, although implicated in a diverse array of cellular functions, possess a similar modular structure. Here we describe a simple and efficient multiplex microbead immunoassay (MMIA), based on Luminex xMAP technology, which allows for the simultaneous detection of 8 phosphorylated SFKs in a single assay. Microbead sets identifiable by unique fluorescence were individually coated with antibodies specific for an individual SFK member. Detection of phosphorylated SFKs was accomplished using a secondary antibody directed against phosphotyrosine. The assay requiresor = 10 microg of cell lysate or nanogram amounts of purified SFK. The use of a generic secondary antibody allows for the expansion of the assay to include any other tyrosine kinase for which a specific antibody exists. Using either mammalian cell lines or purified, recombinant kinases as the SFK source, we demonstrate the utility of the assay by evaluating the phosphorylation status of SFK members following several in vitro manipulations designed to modulate the phosphotyrosine content of the kinases. These results show that the SFK multiplex assay is a robust tool to investigate the function of SFKs in basic and potentially in clinical research.

Markers of myocardial injury have been vital in the assessment of patients with coronary heart disease. Pregnancy associated plasma protein A (PAPP)-A is an insulin-like growth factor (IGF) binding protein (IGFBP)-4 protease and a potential early indicator of unstable angina. We developed an ultrasensitive enzyme-linked immunosorbent assay (ELISA) for PAPP-A and measured serum PAPP-A in patients with biochemical evidence of acute coronary syndrome.Method development was based on pair-wise evaluation of a panel of antibodies and determination of PAPP-A specificity and sensitivity relative to those of a conventional method. Association of PAPP-A with myocardial damage was assessed in serum samples classified based on serum creatine kinase (CK)-MB or cardiac troponin-T levels.Serum PAPP-A was significantly higher in samples with elevated CK-MB or troponin-T than in samples with normal CK-MB (p0.001). Marker-association studies showed strong correlation between PAPP-A and troponin-T (r = 0.59, p0.001) in a subset of troponin-T positive samples. Indications for both parallel as well as divergence in the expression of PAPP-A and troponin-T was also evident when serial timed samples available from a number of patients were analyzed.The data are consistent with the conclusion that expression of PAPP-A is enhanced in patients with biochemical evidence of acute coronary syndrome and suggest strongly that demonstration of PAPP-A association with other cardiac markers might be influenced by their relative release dynamics (timing and duration). The availability of the ultrasensitive PAPP-A ELISA should facilitate systematic investigations of PAPP-A expression in this and other pathophysiological conditions that might involve altered expression of the IGF/PAPP-A system.

Immune checkpoint inhibitors have been proven to be an effective method in improving antitumor immune response. Many immune checkpoint proteins are expressed as soluble forms in circulation and in the tumor and tumor microenvironment. Here we report the development of bead-based Luminex multiplex assays for the quantitative profiling of co-inhibitory and co-stimulating immune checkpoint proteins CTLA-4, PD-1, TIM-3, LAG-3, HVEM. GITRL, BTLA, CD27, CD28, CD40, GITR, PD-L1, B7-1/CD80, B7-2/CD86, and ICOS. In order to explore the use of soluble immune checkpoint proteins as putative cancer biomarkers, we used these multiplex assays to measure checkpoint protein levels in serum samples from breast cancer patients, colon cancer patients, and a corresponding set of normal serum samples. Analysis of the soluble checkpoint protein signatures generated from this multiplex approach revealed a significantly elevated level of soluble TIM-3 protein in the breast cancer serum samples and in the colon cancer serum samples compared to the healthy serum controls (p Citation Format: Wen-Rong Lie, Jehangir Mistry. Quantitative multiplex analysis of immune checkpoint protein expression in circulation and in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2218. doi:10.1158/1538-7445.AM2017-2218

Recombinant ovine Ala-leptin (GenBank Accession No. U84247, of ovine leptin), previously prepared in our laboratory in prokaryotic expression plasmid pMON3401, was mutated using a mutagenesis kit to prepare plasmids encoding for bovine (GenBank Accession No. U50365) and porcine (GenBank Accession No. U59894) leptins and for porcine leptin analogue W4R/R5K. Escherichia coli cells transformed with these plasmids overexpressed large amounts of these proteins upon induction with nalidixic acid. The expressed proteins, found in inclusion bodies, were refolded and purified to homogeneity using subsequently anion- and cation-exchange chromatography. All three purified proteins showed a single band of the expected molecular mass of 16 kDa in SDS-PAGE in the presence of reducing agent and were composed of 90-100% monomers. Proper refolding was evidenced by comparing their CD spectra to those of previously prepared chicken and ovine leptins and to commercially available human leptin. The amino acid content of the purified proteins closely resembled the predicted composition. The biological activity of bovine leptin, porcine leptin, and porcine leptin analogue W4R/R5K was evidenced by their ability to stimulate proliferation of leptin-sensitive BAF/3 cells transfected with a long form of human leptin receptor. All three proteins, as well as ovine and chicken leptins, but not human leptin, exhibited a very high degree of cross-immunoreactivity against antiserum raised against ovine leptin in rabbits. In contrast, none or very low cross-immunoreactivity was observed against antiserum raised against ovine leptin in goats.

Measurements of insulin-like growth factor I(IGF-I), IGF-binding protein-3 (IGFBP-3), and the acid-labile subunit (ALS) are important in assessing the GH-IGF axis. As nearly all IGF-I, IGFBP-3, and ALS circulate in a GH-dependent ternary protein complex, direct determination of the complex may be of significant analytical and clinical importance. We evaluated a panel of monoclonal antibodies (mAb) to human IGFBP-3 and classified them into four groups (G-1 to G-4). G-1 antibodies recognized epitopes that mapped at or near IGFBP-3 ligand (IGF)-binding site. This region overlapped with the G-2 defined region, which, in turn, overlapped with G-3 epitopes defined by one antibody (mAb 3). Only G-1 and G-3 antibodies paired without interference. mAb 9 recognized a conformational epitope (G-4), and mAb 10 was nonreactive. In pairwise mixed antibody evaluation, mAbs in G-2 and G-3 showed simultaneous binding to serum IGFBP-3 complexes in combination with an anti-IGF-I or an anti-ALS antibody. On this basis, two novel enzyme-linked immunosorbent assays (ELISAs) involving IGFBP-3/IGF-I (ELISA-1) and IGFBP-3/ALS (ELISA-2) recognition partners were developed, both demonstrating acceptable analytical performance characteristics. IGFBP-3 complexes measured by ELISA-1 and -2 in samples from normal individuals and subjects with GH deficiency, acromegaly, and GH receptor deficiency more tightly correlated with IGF-I, IGFBP-3, and ALS than IGF-II. ELISA-1 determinations were comparatively more age dependent and, in comparison to ELISA-2, showed better discriminations among the various sample groups, particularly among GH receptor deficiency, normal, and GH deficiency subjects. The development of IGFBP-3 complex ELISAs may simplify diagnostic applications and facilitate investigations of the physiological relevance of the ternary complex formation.

Insulin‐like growth factors (IGFs) and IGF binding proteins (IGFBPs) play an important role in cell growth and differentiation. Clinical and epidemiological studies have indicated that measuring IGFs and IGFBPs in blood has potential implications in assessing growth‐related abnormalities and risks of certain types of cancer. To facilitate the application, we reported a large collection of reference ranges of IGFs and IGFBPs in normal population and evaluations of these molecules in serum and plasma as well as the impact of freeze‐thaw cycles on the measurement. IGF‐I, IGFBP‐3 and ALS showed a similar pattern of change associated with age. Levels of these molecules were low at birth and increased with age through puberty. After puberty the levels declined slowly with age. Overall, IGF‐I, IGFBP‐3 and ALS were slightly higher in females than in males. Free IGF‐I accounted for about 1% of the total IGF‐I and its variation with age was similar to total IGF‐I. IGF‐II levels were also increased with age from birth to puberty, but became stable after puberty. There was little difference in IGF‐II levels between genders. IGFBP‐2 levels declined with age from birth to puberty. Levels of IGFBP‐6 in contrast were increased with age. These IGF binding proteins were higher in males than in females. IGFs, IGFBP‐3 and ALS were 5‐10% higher in serum than in plasma. IGFBP‐2 and IGFBP‐6 differed substantially between serum and plasma. Freeze‐thaw treatment up to five cycles had little impact on plasma levels of IGFs and IGFBP‐3. Our observations suggest that levels of IGFs and their binding proteins are varied with age, gender, and types of specimen and that these variations need to be taken into consideration when IGFs and their binding proteins are utilized in clinic and research. J. Clin. Lab. Anal. 13:166–172, 1999. © 1999 Wiley‐Liss, Inc.

Circulating insulin-like growth factor-I (IGF-I) is predominantly bound in the trimeric complex comprised of IGF binding protein-3 (IGFBP-3) and acid-labile subunit (ALS). Circulating concentrations of IGF-I, IGFBP-3 and ALS are believed to reflect the GH secretory status, but the clinical use of ALS determination is not known. We therefore, determined the: 1) hepatosplanchnic release of ALS by liver vein catheterization (n=30); 2) 24-h diurnal variation of ALS (n=8); 3) normal age-related ranges of circulating ALS (n=1158); 4) diagnostic value of ALS in 108 patients with childhood-onset GH deficiency (GHD). We found: 1) no significant arteriovenous gradient over the liver ofALS, IGF-I, and IGFBP-3; 2) the diurnal variation of ALS was 12% (mean coefficient of variation percent); 3) ALS levels increased throughout childhood with maximal levels in puberty, with a subsequent decrease with age in adults; and 4) ALS levels were below -2 SD in 57 of 79 GHD patients (sensitivity 72%) and above 2 SD in 22 of 29 patients with normal GH response (specificity 76%), which was similar, compared with the diagnostic utility of IGF-I and IGFBP-3. Finally, our findings indicate that hepatic ALS production is not measurable by this approach or, alternatively, that the liver is not the primary source of circulating ALS, IGF-I, or IGFBP-3 in humans. In conclusion, we have provided extensive normal data for a novel ALS assay and found that circulating ALS levels exhibit minor diurnal variation. We suggest that ALS determination may be used in future classification of adults suspected of GHD.

We developed a specific, simple, and rapid RIA for the direct quantification of estrone sulfate (E1S) and established its performance characteristics. The assay has a dynamic range of 0.05–90 μg/L with a detection limit of 0.009 μg/L. Intraassay CVs were 9.2%, 4.5%, and 4.6% at 0.35, 9.0, and 60 μg/L, respectively. Interassay CVs were 8.8%, 5.1%, and 5.5% at 0.076, 0.5, and 12 μg/L, respectively. Linearity of dilution studies showed values of 80–105% of expected, and recovery of E1S added to serum samples ranged from 82% to 102%. Cross-reactivities with structurally related estrogens were

A novel multiplex immunoassay was developed for examining acquired resistance to Receptor Tyrosine Kinase (RTK) inhibitors. RTKs are transmembrane proteins which act as receptors for growth factors, neurotrophic factors and other extracellular signaling molecules. These cell-surface kinases are activated by extracellular ligands leading to receptor dimerization and tyrosine phosphorylation at specific residues in the cytoplasmic tails to initiate RTK-mediated signal transduction. Of the >500 known protein kinases in the human genome there are approximately 60 RTKs. They are central components of cell signaling networks and play crucial roles in normal physiological processes and disease processes ranging from diabetes to cancer. Many RTKs, such as EGFR, HER2, c-Kit, PDGFR and VEGFR, have been used as targets for drug development and RTK-targeted therapies have illustrated the utility of these treatments for selected cancers. However, in many cases, compensatory RTK signaling enables cancer cells to acquire resistance to RTK inhibitors that selectively target a single RTK. For example, some EGFR and HER2 inhibitors have led to resistance and are associated with increased expression of IGF1R. In order to understand the mechanisms of resistance to RTK inhibitors, we have developed a bead-based multiplex immunoassay capable of simultaneously detecting phosphorylation of 18 different RTKs. First we demonstrate detection of RTK phosphorylation in response to growth factor stimulation using various cell lines. Next we examined the specificity of two inhibitors targeting EGFR and HER2. These inhibitors specifically reduced growth factor-stimulated phosphorylation of EGFR and HER2, without inhibiting the activation of other RTKs. Although we did not observe compensatory activation of other RTKs in response to the two EGFR and HER2 inhibitors we tested, this study demonstrates the feasibility of using this novel 18-plex RTK panel for examining the mechanism of resistance to single RTK inhibitors. In summary, the RTK multiplex panel allowed for simultaneous detection of multiple tyrosine phosphorylated RTKs in a specific, sensitive, and reproducible manner. Citation Format: Lu Chen, Anthony J. Saporita, Wen-Rong Lie, Reeti Maheshwari, Melissa Schluter, Jehangir Mistry, Joseph Hwang. Analysis of resistance to RTK inhibitors using a novel RTK multiplex assay. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 205.

The serine/threonine protein kinase Akt is a key node in the PI3K pathway, one of the primary signaling cascades hyperactivated in human cancer. Emerging evidence demonstrates that the three Akt isoforms (Akt1, Akt2, and Akt3) may have unique, isoform-specific roles in key cellular processes such as differentiation and proliferation. We have developed 2-plex assays for each of the Akt isoforms in order to measure the relative levels of phospho- and total Akt1, Akt2, and Akt3. Differential regulation of Akt isoforms was characterized in multiple human cancer cell lines, including SH-SY5Y neuroblastoma cells and MCF-7 breast cancer cells. SH-SY5Y cells were used to study Akt phosphorylation in the context of differentiation. Briefly, SH-SY5Y cells were treated with retinoic acid (RA) for 3 days to induce neuronal differentiation before cells were collected, lysed, and evaluated by Luminex assay. RA-induced differentiation of SH-SY5Y cells stimulated phosphorylation of all three Akt isoforms, with Akt2 displaying the greatest induction. Multi-pathway analysis demonstrated co-induction of phospho-JNK in the RA-treated SH-SY5Y cells, consistent with the role of JNK in RA-mediated differentiation. To study differential regulation of the Akt isoforms in response to growth-stimulatory and growth-inhibitory signals, we used MCF-7 cells. In contrast to SH-SY5Y cells which express all three isoforms, MCF-7 cells only expressed Akt1 and Akt2. Serum-starved MCF-7 cells were cultured in the presence or absence of the PI3K inhibitor LY294002 prior to stimulation with insulin growth factor (IGF). Akt1 showed a greater induction of phosphorylation in response to IGF relative to Akt2. Similarly, whereas LY294002 pre-treatment reduced phospho-Akt1 to baseline levels, it only partially inhibited the IGF-dependent induction of phospho-Akt2. This suggests that Akt1 may be more sensitive to PI3K inhibition than Akt2 in certain human breast cancer cells. Collectively, our results demonstrate that Akt1, Akt2, and Akt3 are differentially regulated in human cancer cells at both the level of phosphorylation and of total protein expression. Citation Format: Anthony J. Saporita, Melissa Schluter, Debra MacIvor, Jehangir Mistry, Joseph Hwang. Interrogation of PI3K signaling via multiplex detection of differential phosphorylation of specific Akt isoforms. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4611.

Monitoring the expression levels of multiple pro- and anti-angiogenic factors in circulation and tumor microenvironment is crucial in examining the role of angiogenesis in cancer pathological processes or in identifying potential biomarkers for oncology drug development. The Luminex xMAP technology allows simultaneous detection of multiple proteins in a single sample and has been used widely in cancer biomarker discovery. Using the Luminex xMAP technology, we developed two Human Angiogenesis Panels (17-plex and 20-plex) and a Mouse Angiogenesis Panel (27-plex) for the simultaneous detection of multiple angiogenic biomarkers in less than 50 μL of human or mouse samples. We report here the protein biomarker profiles of these 37 human angiogenic factors in 1) serum samples, collected from breast cancer and colorectal cancer patients and normal donors, 2) tumor extracts, collected from breast tumor and colorectal tumor extracts and their matched adjacent normal tissue, 3) conditioned media in cultured tumor cells and stromal cells, and in addition, the protein biomarker profiles of 27 mouse angiogenic factors in the conditioned media of various mouse tumor cells and stromal cells. For example, of the 37 human angiogenesis serum protein markers tested, 16 biomarkers [angiopoietin-2 (ANGPT-2), EGF, endoglin, follistatin, G-CSF, HGF, PLGF, sAXL, PDGF-AB/BB, osteopontin (OPN), sHGFR/c-Met, suPAR, sTie-2, sHer2, soluble neuropilin-1 (sNRP-1), and tenascin-C] showed significant difference in expression levels between normal and breast cancer serum samples (p Citation Format: Wen-Rong Lie, Jehangir Mistry. Using multiplex immunoassays for profiling the circulating and tissue angiogenic biomarkers in mouse and human cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3378.

Background: Of the 3 circulating multimeric forms of adiponectin, the high–molecular-weight (HMW) form, as measured by size-exclusion and/or immunoblotting techniques, is a better index of insulin sensitivity for monitoring health and disease than is total adiponectin. We aimed to develop a simple ELISA to measure HMW adiponectin. Methods: We pretreated serum or plasma samples with digestion solution containing proteinase K (Millipore, ESDS). HMW (Millipore, EZHMWA-64K) and total adiponectin (Millipore, EZHADP-61K) concentrations were measured in treated and untreated samples, respectively, from 108 individuals and from 20 morbidly obese patients before and at 1, 3, 6, and 12 months after gastric-bypass surgery. Results: The ELISA has a dynamic range of 3–200 μg/L and a detection limit of 0.8 μg/L. Intraassay and interassay CVs were Conclusion: This simple, rapid ELISA for HMW adiponectin recognizes the HMW isoform, produces results closely correlated with those obtained with Western blotting, and appears to better distinguish BMI-, sex-, and weight loss–associated differences than assays for total adiponectin.

Objective: To use longitudinal profiling of plasma adipokines to distinguish diabetogenic vs. non-diabetogenic obesity syndrome in two new mouse models of polygenic obesity. Research Methods and Procedures: Male mice of the NONcNZO5 strain develop a polygenic obesity syndrome uncomplicated by diabetes, whereas NONcNZO10 males develop a comparable polygenic obesity that precipitates type 2 diabetes. A multiplex immunoassay for simultaneous measurement of insulin and a panel of mouse adipokines (leptin, resistin, adiponectin, interleukin-6, tumor necrosis factor α, macrophage chemoattractant protein-1, plasminogen activator inhibitor-1) were used to profile longitudinal changes in these strains between 4 and 16 weeks of age that might distinguish the non-diabetogenic vs. diabetogenic obesity (diabesity). Results: Both strains became adipose, with NONcNZO5 males attaining a higher mean body weight with a higher percentage fat content. Weight gain in NONcNZO5 was accompanied by a transient peak in plasma insulin (PI) at 8 weeks followed by a decline into normal range, with normoglycemia maintained throughout. In contrast, NONcNZO10 showed no early PI secretory response because both body weight and plasma glucose increased between 4 and 8 weeks. Only after 12 weeks, with hyperglycemia established, was a delayed PI secretory response observed. Neither plasma leptin nor adiponectin concentrations significantly differentiated the two syndromes over time. However, repeated measures ANOVA showed that NONcNZO10 males maintained significantly higher plasma concentrations of two adipokines, resistin and plasminogen activator inhibitor-1, and the pro-inflammatory cytokine/adipokine macrophage chemoattractant protein-1. Discussion: Longitudinal profiling of PI and adipokines in two new mouse models developing moderate obesity demonstrated that specific marker signatures differentiated a non-diabetogenic obesity from a diabetogenic obesity.

Tumors require neovascularization for growth. Consequently, the angiogenesis process is key to understanding tumor development and progression, as well as diagnosis and treatment. Measuring the levels of pro- and anti-angiogenic factors in plasma or serum in cancer patients may provide prognostic information concerning disease processes and mechanisms and the elucidation of potential biomarkers for epidemiological studies or clinical trials. The Luminex xMAP technology, a bead-based multiplex immunoassay for the simultaneous measurement of multiple analytes in a small sample size, has been widely used in cancer biomarker discoveries. We report here the use of two newly developed multiplex human angiogenesis panels to profile the circulating biomarkers commonly used in the angiogenesis pathway analysis. The two panels are 1) MILLIPLEX MAP Human Angiogenesis Panel 1, a 17-plex multiplex immunoassay for the simultaneous quantification of the following 17 angiogenesis biomarkers: Angiopoietin-2, BMP-9, EGF, Endoglin, Endothelin-1, FGF-1, FGF-2, Follistatin, G-CSF, HB-EGF, HGF, IL-8, Leptin, PLGF, VEGF-A, VEGF-C, and VEGF-D, and 2) MILLIPLX MAP Human Angiogenesis Panel 2, a 20-plex multiplex immunoassay for simultaneous quantitation of the following 20 human angiogenesis biomarkers: Angiostatin, soluble E-Selectin, Osteopontin, PDGF-AB/BB, PECAM-1/sCD31, Tenascin C, Thrombospondin-2 (TSP-2), soluble AXL, soluble c-Kit, soluble EGFR, soluble Her2/ErbB2, soluble Her3/ErbB3, soluble HGFR/c-Met, soluble IL-6Rα, soluble Neuropilin-1, soluble Tie-2, soluble urokinase receptor (suPAR), soluble VEGFR1, soluble VEGFR2, and soluble VEGFR3. In this study, we report the use of these 37 angiogenic, growth factor and soluble receptor biomarkers to profile serum samples and plasma samples from a panel of breast cancer and colon cancer patients, with a similar number of normal serum and plasma samples, as a corresponding set, to generate a tumor profile of angiogenic factors using the Luminex xMAP platform. The results of this study demonstrated the utility of these human angiogenesis panels in studying cancer development and cancer biomarker discovery, as well as its potential application in translational research. Citation Format: Wen-Rong Lie, Deborah Droll, Jehangir Mistry. Profiling of serum and plasma angiogenic biomarkers in breast cancer and colon cancer using Luminex xMAP technology-based human angiogenesis multiplex immunoassay panels. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr B01.

e13506 Background: Dysregulation of angiogenesis has been shown to be intimately associated with tumorigenesis and metastatic progression in multiple carcinomas. The objective of this study was to ...

Availability of methods for accurate and reproducible quantification of lepth in various biological fluids in humans and in animals has greatly facilitated research leading to the understanding of its role in various physiological and pathophysiological conditions. Immunoassay techniques provide a simple and robust tool for measurement of biomolecules. In this chapter, I describe the principles behind various types of immunoassay methods, features of several commercially available leptin and leptin receptor immunoassays, and factors that influence leptin measurement using immunoassays.

Development of an ELISA for human insulin that utilizes monoclonal antibodies (mAbs) produced in serum-free medium.Insulin mAbs were produced in vitro by hybridomas in serum-free medium. A two-step ELISA was developed to replace bovine insulin (standard) and bovine serum albumin (assay buffer) with non-animal reagents.The sensitivity of the insulin ELISA was 0.73 uU/mL with a dynamic range of 2-200 uU/mL. No cross-reactivity with either human C-peptide or human proinsulin was observed. The intra- and inter-assay CVs were7%. The mean recovery of insulin added to plasma samples was between 102.2% and 105.7%. The mean linearity of dilution was between 93% and 110% of undiluted plasma samples. The animal serum-free (ASF) insulin ELISA showed no marked degradation of any kit component when stored at 37 degrees C for up to 7 days. Significantly higher fasting insulin levels were observed in overweight or obese subjects (n=12) compared to lean subjects (n=10, p0.05). Feeding markedly increased fasting insulin levels in both lean (p0.02) and overweight or obese (p0.005) subjects. Excellent correlation was observed between insulin levels measured by ASF insulin ELISA and another CE marked insulin ELISA (y=1.06x-0.44, r=1.00, n=44).This novel insulin ELISA provides precision and reliability equal to methods currently used in clinical research and serves as a guide for the development of other serum-free immunoassays.

Polygenic mouse models for obesity-induced type 2 diabetes (T2D) more accurately reflect the most common manifestations of the human disease. Two inbred mouse strains (NON/Lt and NZO/HlLt) separately contributed T2D susceptibility- conferring quantitative trait loci to F1 males. Although chronic administration of rosiglitazone (Rosi) in diet (50 mg/kg) effectively suppressed F1 diabetes, hepatosteatosis was an undesired side effect. Three recombinant congenic strains (designated RCS1, -2, and -10) developed on the NON/Lt background carry variable numbers of these quantitative trait loci that elicit differential weight gain and male glucose intolerance syndromes of variable severity. We previously showed that RCS1 and -2 mice responded to chronic Rosi therapy without severe steatosis, whereas RCS10 males were moderately sensitive. In contrast, another recombinant congenic strain, RCS8, responded to Rosi therapy with the extreme hepatosteatosis observed in the F1. Longitudinal changes in multiple plasma analytes, including insulin, the adipokines leptin, resistin, and adiponectin, and plasminogen activator inhibitor-1 (PAI-1) allowed profiling of the differential Rosi responses in steatosis-exacerbated F1 and RCS8 males vs. the resistant RCS1 and RCS2 or moderately sensitive RCS10. Of these biomarkers, PAI-1 most effectively predicted adverse drug responses. Unexpectedly, mean resistin concentrations were higher in Rosi-treated RCS8 and RCS10. In summary, longitudinal profiling of multiple plasma analytes identified PAI-1 as a useful biomarker to monitor for differential pharmacogenetic responses to Rosi in these new mouse models of T2D.

Tumor and stromal cells secrete a variety of proteins acting as extracellular signals and creating a supportive microenvironment for tumor development, angiogenesis, and metastasis. We used the MILLIPLEX MAP cytokine/chemokine, cancer, angiogenesis, metastasis, MMP, bone metabolism, adipocyte, and cell signaling multi-pathway panels, based on the Luminex xMAP technology, to quantitatively evaluate the protein biomarker expression profiles on cultured mouse and human tumor cells and stromal cells as well as in vivo mouse and human tumor tissues. In the mouse system, biomarker profiling was performed to characterize secreted protein levels in Lewis Lung carcinoma (LLC) cells, B16.10 melanoma cells, b.End3 endothelial cells, and LLC tumors. The in vivo characterization, using primary tumors from mice bearing metastatic LLC, has identified differential expression of a panel of biomarkers, including amphiregulin (AREG), EGF, PECAM-1, KC, MCP-1, MIP-2, MMP-12, and resistin, between the high-fat (45% fat) and AIN-93G (15% fat) fed mice (p Citation Format: Wen-Rong Lie, Jonathan Lipsey, Tim Warmke, Lin Yan, Jehangir Mistry. Quantitative protein profiling of tumor angiogenesis and metastasis biomarkers in mouse and human models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3995. doi:10.1158/1538-7445.AM2014-3995

Multiplex bead-based assays using the Luminex® xMAP® technology allows the simultaneous quantitation of soluble mediators involved in adaptive immune responses. Here we report on the quantitative profiling of the immune secretome and cell signaling target proteins to uncover the characteristics of a CD40L/IFN-γ-activated mature dendritic cell (DC)-based vaccine and the characteristics of T-cell responses generated upon vaccination. Over 200 secreted proteins were evaluated using the Human MILLIPLEX® MAP magnetic bead panels (Cytokine/Chemokine Panels 1-3, High Sensitivity T Cell Panel, CD8 Panel, Th17 Panel, Soluble Cytokine Receptor Panel, Angiogenesis/Growth Factor Panel , MMP & TIMP Panels, IGFBP Panel, Sepsis Panels, Cancer Panels 1-4, CVD Panels 1-3, and others). Additionally, the activation status of a DC-vaccine was profiled using MILLIPLEX® MAP intracellular MAPK/SAPK Pathway multiplex panel. Representative heat maps indicated differences in secreted protein concentrations, biomarker signatures and phosphorylation status in GM-CSF/IL-4-derived immature DCs and CD40L/IFN-γ-activated mature DCs. Furthermore, vaccine-induced antigen-specific CD8+ T cells presented 2 distinct phenotypes based on secretome profiling, and these profiles correlated with clinical outcomes. Consequently, these data demonstrate the utility of MILLIPLEX® panels using the Luminex® xMAP® technology for the characterization of adaptive immune responses in vaccine/immunotherapy setting.

In view of evidence indicating significant involvement of the insulin-like growth factor (IGF) system in the pathogenesis of prostate cancer, we measured serum IGF-I and IGF-binding protein-3 (IGFBP-3) in men with benign prostatic hyperplasia (BPH; n = 75) or prostatic carcinoma (CaP; n = 84). The age-matched patient populations were selected to have circulating prostate-specific antigen (PSA), the most reliable predictor of CaP, in the overlapping diagnostic gray zone range of approximately 4--10 microg/L. Of particular interest was investigation of intact, fragment, and total IGFBP-3 levels in relation to PSA, which is also a well established IGFBP-3 protease. Among the key findings were significantly higher IGF-I and intact IGFBP-3 levels in CaP vs. BPH (P0.001), whereas changes in fragment and total IGFBP-3 were statistically insignificant. As expected, total PSA levels were similar in the two groups of patients (P = 0.173), whereas free PSA levels were significantly lower in those with CaP (P0.001). IGF-I and IGFBP-3 (intact and total) correlated significantly (P = 0.024 to0.001) and inversely (r = -0.26 to -0.35) with free PSA in BPH, but not in CaP, and no correlations were found in comparisons involving total PSA. Statistical analysis of the various markers and their combinations indicated enhanced performance of IGF-I/free PSA [receiver operating characteristics area under the curve (AUC) = 0.728] and intact IGFBP-3/free PSA (AUC = 0.737) ratios in discriminating between BPH and CaP compared with the currently used free/total PSA ratio (AUC = 0.689). Multivariate logistic regression models confirmed the observed relationships and identified IGF-I/free PSA and intact IGFBP-3/free PSA as independent factors in predicting the presence of CaP. We conclude that increases in IGF-I and intact IGFBP-3 levels are positively associated with the presence of CaP in this group of patients with low to moderately elevated PSA, and that their measurements in relation to PSA may help improve diagnostic discrimination between BPH and prostate cancer.

Posttranslational modifications, particularly proteolysis, may play a significant role in the regulation of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) physiology, and thus, measurement of modified variants of IGFBP-3 and/or their combination ratios may have important research and diagnostic relevance. Based on evaluation of a panel of monoclonal and polyclonal IGFBP-3 antibodies, we constructed three new enzyme-linked immunosorbent assays (ELISAs) using a common capture and polyclonal (ELISA-3) or monoclonal (ELISA-1 and -2) detection antibodies and evaluated them in a two-step colorimetric procedure. Evaluation of ELISA-1-3 demonstrated detection limit, dynamic range, overall precision, and recovery of the added IGFBP-3 to be generally less than 0.04 microg/L, 2-100 microg/L, less than 10%, and 91-113%, respectively. IGF-I and -II, and IGFBP-1, -2, -4, -5, and -6 did not interfere. In normal adult sera (n = 26), seminal plasma (n = 14), pregnancy sera (n = 30), and amniotic fluid (n = 30), ELISA-1-3 detected significantly different IGFBP-3 levels (by up to 6-fold, on the average), whereas levels in seminal plasma determined by ELISA-1 were undetectable. Comparison of the values obtained vs. corresponding levels by an established method (Diagnostic Systems Laboratories, Inc., active IGFBP-3 ELISA) were similarly sample dependent and, on the average, varied by up to 19-fold. Only ELISA-3 compared well with the Diagnostic Systems Laboratories, Inc., IGFBP-3 ELISA when samples from normal adults were analyzed. The observed variability could not be totally explained by 50% lower reactivity of ELISA-1-3 for glycosylated IGFBP-3 vs. the nonglycosylated form, and changes in phosphorylation had no effect on immunoreactivity. Evaluation of IGFBP-3 after proteolysis by seminal plasma, plasmin, or thrombin suggested recognition of intact IGFBP-3 by ELISA-1, whereas ELISA-3 appeared to measure intact and proteolyzed IGFBP-3 (total IGFBP-3) with similar potency. In contrast, levels determined by ELISA-2 increased severalfold, indicating preferential recognition of IGFBP-3 fragments. We propose that immunoassay capable of differential determination of IGFBP-3 variants may help better define the physiological importance and potential clinical value of IGFBP-3 measurements.

Background: Insulin-like growth factors (IGFs), in particular IGF-I and IGF-II, strongly stimulate the proliferation of a variety of cancer cells, including those from lung cancer. To examine the possible causal role of IGFs in lung cancer development, we compared plasma levels of IGF-I, IGF-II, and an IGF-binding protein (IGFBP-3) in patients with newly diagnosed lung cancer and in control subjects. Methods: From an ongoing hospital-based, case‐control study, we selected 204 consecutive patients with histologically confirmed, primary lung cancer and 218 control subjects who were matched to the case patients by age, sex, race, and smoking status. IGF-I, IGF-II, and IGFBP-3 plasma levels were measured by enzyme-linked immunosorbent assay and then divided into quartiles, based on their distribution in the control subjects. Associations between the IGF variables and lung cancer risk were estimated by use of odds ratios (ORs). Reported P values are two-sided. Results: IGF and IGFBP-3 levels were positively correlated (all r>.27; all P

To facilitate broader applications of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) analysis, we developed procedures for their measurements in extracts of whole blood dried on filter paper. A single 8-mm diameter filter paper disc containing about 13 microL blood was used. IGFBP-3 was efficiently extracted in a buffer within 1 h of incubation. IGF-I extraction involved incubation in buffer followed by acidification and neutralization steps. Blood spot assays showed intra- and interassay coefficients of variation (including interspot variations) of 5.4-16.7% for IGF-I and 6.6-11.7% for IGFBP-3; recoveries were 97 +/- 7.1% and 101 +/- 8.7%, respectively. Recoveries of IGF-I and IGFBP-3 in response to 4- to 8-fold variations in extraction buffer volume were 97 +/- 8.2% and 107 +/- 6.1%, respectively. Dried blood spot IGF-I and IGFBP-3 showed greater than 1-month stability at -20 C, 4 C, and room temperature and retained more than 65% of the immunoreactivity after approximately 1 month at 37 C. Both IGF-I and IGFBP-3 were contained within the plasma fraction of whole blood, and variations (mean +/- SD) in IGF-I (204 +/- 29 micrograms/L) and IGFBP-3 (4.4 +/- 0.48 mg/L) measured in extracts of dried blood spot with adjusted hematocrit of 0.2-0.62 were acceptable. IGF-I and IGFBP-3 in paired plasma and dried blood spot extracts of random samples (n = 46) showed excellent correlation (r0.94) with slopes of near unity. Compared to conventional methods, the filter paper procedures were equally effective in distinguishing IGF-I and IGFBP-3 levels in untreated GH receptor-deficient (n = 11) and age-matched normal controls (n = 16). We conclude that blood collected on filter paper is ideal for IGF-I and IGFBP-3 analysis and may find applications in pediatric and large scale infant screening programs.

Although the acid-labile subunit (ALS) of the approximately 150-kDa insulin-like growth factor (IGF)-binding protein (IGFBP) complex was described over a decade ago, details of ALS physiology have remained largely uncertain. We evaluated antibodies to synthetic human ALS and constructed a noncompetitive ALS enzyme-linked immunosorbent assay. Whereas uncomplexed ALS is directly measured, determination of total levels required sample pretreatment with SDS, which was found to optimally dissociate complexed ALS and significantly enhance ALS immunoreactivity. ALS in random adult sera was approximately 50% uncomplexed, and samples devoid of complexed ALS by immunoaffinity separation contained about 54% of the total levels. Serum ALS fractionated by gel filtration high performance liquid chromatography eluted in a single peak at approximately 150 kDa with IGF-I and IGFBP-3, but appeared at about 400-500 kDa after sample acidification and fractionation under acidic condition. The unexpected shift in ALS immunoreactivity remained unchanged when acid-neutralized or SDS-treated samples were fractionated under neutral pH and was reproducible when the 150-kDa complex was isolated, treated with acid or SDS, and rechromatographed. ALS in adult sera more tightly correlated with IGFBP-3 than IGF-I or IGF-II. The total levels (mean +/- SD) were 16.7 +/- 3.7 mg/L in 22 normal subjects, 28.3 +/- 8.1 mg/L in 20 acromegalic patients, and 9.5 +/- 3.8 in 32 GH-deficient adults. Little or no ALS was detectable in amniotic fluid, cerebrospinal fluid, seminal plasma, or milk, whereas high levels were present in synovial fluid. The development of ALS enzyme-linked immunosorbent assay should greatly facilitate further investigations of this unique glycoprotein.

Accurate measurement of insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is important for precise definition of its physiological roles and potential diagnostic values. Because altered phosphorylation results in altered IGFBP-1 immunoreactivity, current assays may significantly underestimate or fail to detect physiological changes in the IGFBP-1 concentrations. We developed three ELISAs (ELISA 1–3) using a common capture but three different detection antibodies. IGFBP-1 in serum, synovial fluid (SF), cerebrospinal fluid (CSF), and amniotic fluid (AF) were measured before and after treatment with alkaline phosphatase (ALP). Among the methods, only ELISA-1 was unaffected by IGFBP-1 phosphorylation and generated identical results before and after ALP treatment. The serum and SF values by ELISA-2 and -3 were lower by ∼4- to 10-fold, but increased after ALP treatment to within 66–98% of those by ELISA-1. The medians in AF, and to a lesser extent in CSF, by all methods were similar and did not change significantly after dephosphorylation. ELISA-1 showed excellent correlation with ELISA-2, ELISA-3, and a commercial IGFBP-1 IRMA only after ALP-treated samples were analyzed by the comparative methods. ELISA-1 is highly specific for IGFBP-1 and demonstrated acceptable analytical performance characteristics.

Metastasis is a major cause of death in cancer patients. We report here the use of a multiplex proteomic analysis approach to in vitro and in vivo identify biomarkers involved in melanoma invasion/metastasis. An in vitro quantitative profile of the secretome (>200 proteins) was done on non-metastatic melanoma cell lines (A375, LH, M14, DM.6, Lox, and WUmel19) and their metastatic RhoC-expressing counterparts (A375-RhoC, LH-RhoC, M14-RhoC, DM.6-RhoC, Lox-RhoC, and WUmel19-RhoC). A heat map cluster analysis was performed to characterize protein expression levels on metastatic vs. the non-metastatic melanoma cells and identify secreted markers with significantly altered expression that may be involved in tumor invasion, angiogenesis, and metastasis. An in vivo characterization, using an animal model of human melanoma pulmonary metastasis, has identified differential expression of tissue and circulating protein biomarkers in tumor and sera, respectively. Moreover, use of species-specific assays has allowed us to dissect the contribution of stroma (mouse) and tumor (human). Increased expression of a panel of markers, including IL-8, PLGF, FGF-2, follistatin, MMP-1, MMP-9, TIMP-1, TIMP-2, GDF15, NSE, OPN, and MIF was detected in vivo in both tumor and sera, indicating their roles in inducing angiogenesis, tumor invasion and metastasis. Cell signaling pathway multiplex analyses revealed the activation of PI3K/mTOR pathway in the tumor. Elevated levels of phosphorylated targets of PI3K/mTOR pathway, p70S6K (pT412), GSK3α (pS21), GSK3β (pS9), RPS6 (pS235/236), TSC2 (pS939) and mTOR (pS2448) were detected in the pulmonary tumor metastasis. Hence this human melanoma pulmonary metastasis model may prove to be a useful animal model for studying the actions of PI3K/mTOR inhibitors in melanoma metastasis. Altogether, these in vitro and in vivo studies using multiplex proteomic analysis may assist in the discovery of biomarkers and therapeutic targets for human melanoma interventions. Citation Format: Wen-Rong Lie, Michelle Becker-Hapak, Megan Chan, James Graham, Jehangir Mistry, Gerald Linette, Beatriz Carreno. In vitro and in vivo characterization of protein biomarkers of metastasis in melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 409. doi:10.1158/1538-7445.AM2013-409