Supplementary Methods, Table S1, Figures S1-7. Methods for quantitative multiplex proteomics imaging (QMPI) Clinical studies: Statistical plan Table S1. Clinical Validation Study. Comparison of Predictive Value of the 8-Biomarker Assay for Favorable Pathology with D'Amico Risk Categories. Figure S1. Outline of all four quantitative multiplex immunofluorescence triplex assay formats Figure S2. Clinical validation study, full cohort (N=276): performance for "GS 6" pathology (surgical Gleason =3+3 and localized {less than or equal to}T3a). A) Sensitivity (P[risk score> threshold| "non-GS 6" pathology]) of the assay, as a function of medical decision level. Figure S3. Clinical validation study, full cohort (N=274): performance for prediction of favorable pathology (surgical Gleason {less than or equal to}3+4 and organ-confined {less than or equal to}T2). Figure S4. Clinical validation study, Subset of validation cohort that contained sufficient annotation for National Comprehensive Cancer Network (NCCN) and D'Amico categorization (N=256) Figure S5. Clinical validation study: performance for prediction of favorable pathology. Figure S6. Net Reclassification Index analysis illustrates how biomarker assay categories of favorable (risk score {less than or equal to}0·33) and non-favorable (risk score >0·8) may supplement NCCN Figure S7. Decision Curve Analysis provides another method for characterizing performance of different risk systems and at different cut points.

Autoimmune diseases vary in the magnitude and diversity of autoantibody profiles, and these differences may be a consequence of different types of breaks in tolerance. Here, we compared the disparate autoimmune diseases autoimmune polyendocrinopathy–candidiasis–ecto-dermal dystrophy (APECED), systemic lupus erythematosus (SLE), and Sjogren’s syndrome (SjS) to gain insight into the etiology of breaks in tolerance triggering autoimmunity. APECED was chosen as a prototypical monogenic disease with organ-specific pathology while SjS and SLE represent polygenic autoimmunity with focal or systemic disease. Using protein microarrays for autoantibody profiling, we found that APECED patients develop a focused but highly reactive set of shared mostly anti-cytokine antibodies, while SLE patients develop broad and less expanded autoantibody repertoires against mostly intracellular autoantigens. SjS patients had few autoantibody specificities with the highest shared reactivities observed against Ro-52 and La. RNA-seq B-cell receptor analysis revealed that APECED samples have fewer, but highly expanded, clonotypes compared with SLE samples containing a diverse, but less clonally expanded, B-cell receptor repertoire. Based on these data, we propose a model whereby the presence of autoreactive T-cells in APECED allows T-dependent B-cell responses against autoantigens, while SLE is driven by breaks in peripheral B-cell tolerance and extrafollicular B-cell activation. These results highlight differences in the autoimmunity observed in several monogenic and polygenic disorders and may be generalizable to other autoimmune diseases.

Abstract Purpose: Prostate cancer aggressiveness and appropriate therapy are routinely determined following biopsy sampling. Current clinical and pathologic parameters are insufficient for accurate risk prediction leading primarily to overtreatment and also missed opportunities for curative therapy. Experimental Design: An 8-biomarker proteomic assay for intact tissue biopsies predictive of prostate pathology was defined in a study of 381 patient biopsies with matched prostatectomy specimens. A second blinded study of 276 cases validated this assay's ability to distinguish “favorable” versus “nonfavorable” pathology independently and relative to current risk classification systems National Comprehensive Cancer Network (NCCN and D'Amico). Results: A favorable biomarker risk score of ≤0.33, and a nonfavorable risk score of >0.80 (possible range between 0 and 1) were defined on “false-negative” and “false-positive” rates of 10% and 5%, respectively. At a risk score ≤0.33, predictive values for favorable pathology in very low-risk and low-risk NCCN and low-risk D'Amico groups were 95%, 81.5%, and 87.2%, respectively, higher than for these current risk classification groups themselves (80.3%, 63.8%, and 70.6%, respectively). The predictive value for nonfavorable pathology was 76.9% at biomarker risk scores >0.8 across all risk groups. Increased biomarker risk scores correlated with decreased frequency of favorable cases across all risk groups. The validation study met its two coprimary endpoints, separating favorable from nonfavorable pathology (AUC, 0.68; P < 0.0001; OR, 20.9) and GS-6 versus non–GS-6 pathology (AUC, 0.65; P < 0.0001; OR, 12.95). Conclusions: The 8-biomarker assay provided individualized, independent prognostic information relative to current risk stratification systems, and may improve the precision of clinical decision making following prostate biopsy. Clin Cancer Res; 21(11); 2591–600. ©2015 AACR.

88 Background: Standard clinical and pathological parameters derived from diagnostic biopsy are insufficient to accurately assess final prostate tumor pathology of patients with biopsy Gleason grades 3+3 or 3+4. We developed a novel assay (ProMark) that performs quantitative measurements of 8 protein markers from prostate biopsy FFPE sections. In the validation study, assay risk scores were strongly predictive of final prostate tumor pathology with a C-stat of 0.69 (95%CI = 0.63 – 0.76) (p<0.0001). By design, the train-test (N=381) and validation (N=274) studies were enrichment studies, with a higher % of aggressive disease than in the intended use population. Here we study 293 needle biopsy cases that have come to our CLIA lab for ProMark testing over a four month period. The objective of this study is to establish the ProMark score distribution for these ‘real world’ clinical use patients, and to confirm that this distribution matches our clinical validation study. Methods: To establish prevalence of aggressive disease in the intended use population, we used the Institutional Urology Prostate Cancer Database at Johns Hopkins. Among 9,305 men with biopsy Gleason 3+3 or 3+4 and prostatectomy from 2004-2014 the distribution of favorable (GS<4+3 & organ confined) and unfavorable (GS≥4+3 or non-organ confined) based on surgical pathology is 73.1% vs. 26.9%. The adjusted risk score distribution from the validation trial (N=274) is then compared to the CLIA lab samples (N=293), based on cumulative distributions and binomial confidence intervals. Results: Comparison of the risk score distribution of early clinical data with the population-adjusted validation score distribution shows good agreement based on 95% CIs. Table shows expected and measured frequencies in Low, Intermediate and High risk categories. The K-S test for comparison of distributions has p-value=0.44, supporting equivalence of distribution. Conclusions: The results of our study show that early clinical practice closely matches expectations from controlled clinical studies. [Table: see text]

Activating mutations of FMS-like tyrosine kinase-3 (FLT3) are found in approximately 30% of patients with acute myeloid leukemia (AML). FLT3 is therefore an attractive drug target. However, the molecular mechanisms by which FLT3 mutations lead to cell transformation in AML remain unclear. To develop a better understanding of FLT3 signaling as well as its downstream effectors, we performed detailed phosphoproteomic analysis of FLT3 signaling in human leukemia cells. We identified over 1000 tyrosine phosphorylation sites from about 750 proteins in both AML (wild type and mutant FLT3) and B cell acute lymphoblastic leukemia (normal and amplification of FLT3) cell lines. Furthermore, using stable isotope labeling by amino acids in cell culture (SILAC), we were able to quantified over 400 phosphorylation sites (pTyr, pSer, and pThr) that were responsive to FLT3 inhibition in FLT3 driven human leukemia cell lines. We also extended this phosphoproteomic analysis on bone marrow from primary AML patient samples, and identify over 200 tyrosine and 800 serine/threonine phosphorylation sites in vivo. This study showed that oncogenic FLT3 regulates proteins involving diverse cellular processes and affects multiple signaling pathways in human leukemia that we previously appreciated, such as Fc epsilon RI-mediated signaling, BCR, and CD40 signaling pathways. It provides a valuable resource for investigation of oncogenic FLT3 signaling in human leukemia.

TET family enzymes convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. Here, we show that Tet1 and Tet2 are Oct4-regulated enzymes that together sustain 5hmC in mouse embryonic stem cells (ESCs) and are induced concomitantly with 5hmC during reprogramming of fibroblasts to induced pluripotent stem cells. ESCs depleted of Tet1 by RNAi show diminished expression of the Nodal antagonist Lefty1 and display hyperactive Nodal signaling and skewed differentiation into the endoderm-mesoderm lineage in embryoid bodies in vitro. In Fgf4- and heparin-supplemented culture conditions, Tet1-depleted ESCs activate the trophoblast stem cell lineage determinant Elf5 and can colonize the placenta in midgestation embryo chimeras. Consistent with these findings, Tet1-depleted ESCs form aggressive hemorrhagic teratomas with increased endoderm, reduced neuroectoderm, and ectopic appearance of trophoblastic giant cells. Thus, 5hmC is an epigenetic modification associated with the pluripotent state, and Tet1 functions to regulate the lineage differentiation potential of ESCs.

Cholangiocarcinoma, also known as bile duct cancer, is the second most common primary hepatic carcinoma with a median survival of less than 2 years. The molecular mechanisms underlying the development of this disease are not clear. To survey activated tyrosine kinases signaling in cholangiocarcinoma, we employed immunoaffinity profiling coupled to mass spectrometry and identified DDR1, EPHA2, EGFR, and ROS tyrosine kinases, along with over 1,000 tyrosine phosphorylation sites from about 750 different proteins in primary cholangiocarcinoma patients. Furthermore, we confirmed the presence of ROS kinase fusions in 8.7% (2 out of 23) of cholangiocarcinoma patients. Expression of the ROS fusions in 3T3 cells confers transforming ability both in vitro and in vivo, and is responsive to its kinase inhibitor. Our data demonstrate that ROS kinase is a promising candidate for a therapeutic target and for a diagnostic molecular marker in cholangiocarcinoma. The identification of ROS tyrosine kinase fusions in cholangiocarcinoma, along with the presence of other ROS kinase fusions in lung cancer and glioblastoma, suggests that a more broadly based screen for activated ROS kinase in cancer is warranted.

Anaplastic large cell lymphoma represents a subset of neoplasms caused by translocations that juxtapose the anaplastic lymphoma kinase (ALK) to dimerization partners. The constitutive activation of ALK fusion proteins leads to cellular transformation through a complex signaling network. To elucidate the ALK pathways sustaining lymphomagenesis and tumor maintenance, we analyzed the tyrosine-kinase protein profiles of ALK-positive cell lines using 2 complementary proteomic-based approaches, taking advantage of a specific ALK RNA interference (RNAi) or cell-permeable inhibitors. A well-defined set of ALK-associated tyrosine phosphopeptides, including metabolic enzymes, kinases, ribosomal and cytoskeletal proteins, was identified. Validation studies confirmed that vasodilator-stimulated phosphoprotein and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/inosine monophosphate cyclohydrolase (ATIC) associated with nucleophosmin (NPM)-ALK, and their phosphorylation required ALK activity. ATIC phosphorylation was documented in cell lines and primary tumors carrying ALK proteins and other tyrosine kinases, including TPR-Met and wild type c-Met. Functional analyses revealed that ALK-mediated ATIC phosphorylation enhanced its enzymatic activity, dampening the methotrexate-mediated transformylase activity inhibition. These findings demonstrate that proteomic approaches in well-controlled experimental settings allow the definition of informative proteomic profiles and the discovery of novel ALK downstream players that contribute to the maintenance of the neoplastic phenotype. Prediction of tumor responses to methotrexate may justify specific molecular-based chemotherapy.

A major question regarding the sensitivity of solid tumors to targeted kinase inhibitors is why some tumors respond and others do not. The observation that many tumors express EGF receptor (EGFR), yet only a small subset with EGFR-activating mutations respond clinically to EGFR inhibitors (EGFRIs), suggests that responsive tumors uniquely depend on EGFR signaling for their survival. The nature of this dependence is not understood. Here, we investigate dependence on EGFR signaling by comparing non-small-cell lung cancer cell lines driven by EGFR-activating mutations and genomic amplifications using a global proteomic analysis of phospho-tyrosine signaling. We identify an extensive receptor tyrosine kinase signaling network established in cells expressing mutated and activated EGFR or expressing amplified c-Met. We show that in drug sensitive cells the targeted tyrosine kinase drives other RTKs and an extensive network of downstream signaling that collapse with drug treatment. Comparison of the signaling networks in EGFR and c-Met-dependent cells identify a “core network” of ≈50 proteins that participate in pathways mediating drug response.

3134 Activating mutations of FMS-like tyrosine kinase-3 (FLT3) are found in approximately one third of patients with acute myeloid leukemia (AML) and are an attractive drug target. Recently, FLT3 has been implicated in the pathogenesis of infant and childhood ALL. There is substantial experimental evidence, both in vitro and in vivo, to support the notion that these mutations play an important role in the initiation and/or maintenance of AML in a subset of patients. However, the molecular mechanisms by which FLT3 mutations lead to transformation of hematopoietic stem cells remain unclear. To develop a better understanding of FLT3 signaling as well as its downstream mediators, we performed detailed phoshoproteomic analysis of FLT3 signaling in leukemia cells. Using immunoaffinity purification of phospho-tyrosine peptides (PhosphoScan®) followed by tandem mass spectrometry, we identified over 1000 tyrosine phosphorylation sites from approximately 20 AML (FLT3-ITD and wild type) and B-ALL (normal and amplification of FLT3) cell lines. Not only did we identify novel tyrosine phosphorylation sites in FLT3, but also we identified many phosphosites unique to FLT3-ITD AML cell lines. In addition, we investigated which of these phosphosites were responsive to FLT3 inhibitors. To further investigate the FLT3 signaling pathway, we employed stable isotopic amino acids in cell culture (SILAC) to differentially label proteins in FLT3 inhibited versus uninhibited leukemia cell lines. Quantitative SILAC experiment identified over 200 phosphorylation sites, whose tyrosine phosphorylation status is regulated by FLT3. Finally, for the first time, we performed phosphoproteomic analysis from AML patient samples. This study provided the most comprehensive tyrosine phosphorylation signaling profile reported for activated FLT3 to date These studies have important implications for the design of novel therapeutic approaches and for the identification of biomarkers for leukemia with activated FLT3.

To ensure survival in the face of genomic insult, cells have evolved complex mechanisms to respond to DNA damage, termed the DNA damage checkpoint. The serine/threonine kinases ataxia telangiectasia-mutated (ATM) and ATM and Rad3-related (ATR) activate checkpoint signaling by phosphorylating substrate proteins at SQ/TQ motifs. Although some ATM/ATR substrates (Chk1, p53) have been identified, the lack of a more complete list of substrates limits current understanding of checkpoint pathways. Here, we use immunoaffinity phosphopeptide isolation coupled with mass spectrometry to identify 570 sites phosphorylated in UV-damaged cells, 498 of which are previously undescribed. Semiquantitative analysis yielded 24 known and 192 previously uncharacterized sites differentially phosphorylated upon UV damage, some of which were confirmed by SILAC, Western blotting, and immunoprecipitation/Western blotting. ATR-specific phosphorylation was investigated by using a Seckel syndrome (ATR mutant) cell line. Together, these results provide a rich resource for further deciphering ATM/ATR signaling and the pathways mediating the DNA damage response.

Despite the success of tyrosine kinase-based cancer therapeutics, for most solid tumors the tyrosine kinases that drive disease remain unknown, limiting our ability to identify drug targets and predict response. Here we present the first large-scale survey of tyrosine kinase activity in lung cancer. Using a phosphoproteomic approach, we characterize tyrosine kinase signaling across 41 non-small cell lung cancer (NSCLC) cell lines and over 150 NSCLC tumors. Profiles of phosphotyrosine signaling are generated and analyzed to identify known oncogenic kinases such as EGFR and c-Met as well as novel ALK and ROS fusion proteins. Other activated tyrosine kinases such as PDGFRalpha and DDR1 not previously implicated in the genesis of NSCLC are also identified. By focusing on activated cell circuitry, the approach outlined here provides insight into cancer biology not available at the chromosomal and transcriptional levels and can be applied broadly across all human cancers.

STAT5 is constitutively phosphorylated in leukemic cells in approximately 70% of acute myeloid leukemia (AML) patients. To identify kinase candidates potentially responsible for STAT5 phosphorylation, we used liquid chromatography–tandem mass spectrometry (LC–MS/MS) mass spectrometry to detect phosphoproteins in AML cell lines. We established TEL-ARG and BCR-ABL fusion proteins as the mechanism underlying STAT5 phosphorylation in HT-93 and KBM-3 cells, respectively. In addition, we identified a JAK2 pseudokinase domain mutation in HEL cells and using siRNA downregulation, established JAK2 as the kinase responsible for phosphorylating STAT5. This study illustrates the benefit of LC–MS/MS mass spectrometry and siRNA for the identification of novel targets and mutations.

Forkhead transcription factors are key participants in development and immune regulation. Here we demonstrate that absence of the gene encoding the forkhead transcription factor Foxp1 resulted in a profound defect in early B cell development. Foxp1 deficiency was associated with decreased expression of all B lineage genes in B220+ fetal liver cells as well as with a block in the transition from pro–B cell to pre–B cell involving diminished expression of recombination-activating genes 1 and 2. Foxp1 bound to the Erag enhancer and was involved in controlling variable-(diversity)-joining recombination of the gene encoding immunoglobulin heavy chain in a B cell lineage–specific way. Our results identify Foxp1 as an essential participant in the transcriptional regulatory network of B lymphopoiesis.

The NFAT family of Ca-regulated transcription factors has a critical role in vertebrate development and function. In resting cells, NFAT proteins are heavily phosphorylated and reside in the cytoplasm; upon stimulation they are dephosphorylated by the calmodulindependent phosphatase calcineurin and translocate to the nucleus. NFAT proteins are not represented in invertebrates, but the pathways regulating their subcellular localization -Ca homeostasis, Ca influx, calcineurin and NFAT kinases -are strongly conserved across species. Using a genome-wide RNAi screen in Drosophila, we have identified several previously unsuspected modulators of NFAT function: Drosophila and human STIM proteins which are powerful regulators of Ca influx in response to depletion of Ca stores; DYRK, a kinase that directly phosphorylates a conserved motif in the NFAT regulatory domain and deactivates NFAT; and other candidates that affect diverse aspects of Ca signalling and NFAT regulation. Thus genome-wide RNAi screening in Drosophila can be successfully used to cross evolutionary boundaries and identify novel regulators of a transcription factor that is expressed only in vertebrates.

Tyrosine kinases are aberrantly activated in numerous malignancies, including acute myeloid leukemia (AML). To identify tyrosine kinases activated in AML, we developed a screening strategy that rapidly identifies tyrosine-phosphorylated proteins using mass spectrometry. This allowed the identification of an activating mutation (A572V) in the JAK3 pseudokinase domain in the acute megakaryoblastic leukemia (AMKL) cell line CMK. Subsequent analysis identified two additional JAK3 alleles, V722I and P132T, in AMKL patients. JAK3A572V, JAK3V722I, and JAK3P132T each transform Ba/F3 cells to factor-independent growth, and JAK3A572V confers features of megakaryoblastic leukemia in a murine model. These findings illustrate the biological importance of gain-of-function JAK3 mutations in leukemogenesis and demonstrate the utility of proteomic approaches to identifying clinically relevant mutations.