Mohan, Chandra

Abstract Given the morbidity and mortality associated with colorectal cancer, novel biomarkers are clearly warranted, especially for early detection, particularly for advanced adenomas. An earlier 1317-plex aptamer-based proteomic screen of stool proteins revealed 92 proteins to be significantly elevated in CRC stool, with the most discriminatory proteins being MMP9, haptoglobin, myeloperoxidase, fibrinogen, and adiponectin (PMID: 34117903). Results from a recent 2000-plex proteomic screen of CRC stools are detailed below, while a 11,000-plex aptamer based proteomic screen is in progress. Comprehensive proteomic screening revealed 116 proteins to be differentially expressed in CRC stool compared to control stool, with 45 being elevated 2-fold or higher. 37 of these proteins were ELISA validated in 3 independent cohorts. Stool MMP-8, MMP-9, Hemoglobin, PGRP-S, Haptoglobin, Myeloperoxidase and Fibrinogen emerged as being most discriminatory for distinguishing CRC from healthy controls (AUC: 0.91-0.95), while Stool Fibrinogen, MMP-9, Hemoglobin, MMP-8, and PGRP-S best distinguished advanced adenoma from healthy control (HC) stool, with stool Fibrinogen topping the list with an ROC AUC value of 0.86, as detailed in Table 1. Functional pathway analysis revealed a significant over-representation of pathways related to anti-oxidant activity, integrin/receptor binding, cytokines, blood coagulation, and lipoprotein biosynthesis in patients with CRC compared to HC. Nuclear Factor IC (NFIC) and IKZF2 were identified as key regulators of the molecular cascades over-represented in CRC. Stool Fibrinogen, MMP-8, MMP-9, PGRP-S, Haptoglobin, and Myeloperoxidase emerge as promising biomarkers for distinguishing CRC/advanced adenomas/healthy stools, outperforming Hemoglobin. Thus, comprehensive proteomics and independent ELISA validation have uncovered novel stool biomarkers for identifying CRC and advanced adenomas, that warrant further head to head comparison against current diagnostic tests. Citation Format: Chandra Mohan, Kamala Vanarsa, Jessica Castillo, Robert Bresalier, Nicholas Chia. 11,000-plex aptamer based proteomics of colorectal cancer stools for the discovery of novel disease biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1845.

AbstractObjectiveTo discover a novel peptoid antagonist that targets the interleukin‐15 (IL‐15) receptor and to evaluate its therapeutic efficacy in the treatment of inflammation and arthritis.MethodsA new compound (IFRA3, interleukin‐15 receptor antagonist 3) was discovered using a unique on‐bead two‐colour combinatorial cell screening of a peptoid library. The interaction of IFRA3 with IL‐15 receptor was assessed by in vitro pull‐down and thermal shift assays. The efficacy of IFRA3 in treating inflammation and arthritis was evaluated in mouse models.ResultsIFRA3Q1 (a tetrameric derivative of IFRA3) inhibited the activity of IL‐15 and suppressed CTLL‐2 cell proliferation (which depends on IL‐15 activity). IFRA3Q1 exhibited strong in vivo anti‐inflammatory activity in carrageenan‐induced inflammation in mice. Furthermore, IFRA3Q1 inhibited collagen‐induced arthritis in DBA/1J mice.ConclusionBy binding to and inhibiting the function of IL‐15 receptor, IFRA3Q1 exhibited significant anti‐arthritis activity. Our findings suggest that IFRA3Q1 represents a new paradigm for arthritis therapy by targeting IL‐15 signalling.

SummaryNuclear factor (NF)-κB is a transcription factor implicated in the pathogenesis of autoimmune disorders such as rheumatoid arthritis (RA). Here we have examined the effect of intra-articular administration of the IKK inhibitor, NEMO-binding domain peptide (NBD), on the severity of collagen-induced arthritis (CIA). NBD peptides were injected intra-articularly into the knee joints of DBA/1J mice after the onset of disease. Collagen-injected mice given a scrambled peptide served as controls. Arthritis severity was determined by visual examination of paws. Intra-articular NBD injection reduced the arthritis score and ameliorated morphological signs of bone destruction compared to the controls. Serum levels of type-II collagen-specific immunoglobulin (Ig)G2a antibodies were lower in NBD-treated mice versus the control mice, whereas the levels of type-II collagen-specific IgG1 antibodies were increased by NBD treatment. NBD treatment diminished the proinflammatory cytokines interleukin (IL)-17 and interferon (IFN)-γ in serum, but increased the regulatory cytokine IL-10. NBD-treated CIA mice exhibited significantly higher percentages and numbers of forkhead box protein 3 (FoxP3+)CD4+CD25+ regulatory T cells than controls. Immunofluorescence analysis of NBD-treated mice revealed that FoxP3 and Ym1, a marker of alternatively activated macrophages, were juxtaposed to each other within draining inguinal lymph nodes. Intra-articular administration of NBD peptide is effective as an experimental therapy in a murine model of RA. Nevertheless, the intra-articular treatment modality is still associated with systemic effects on the immune system.