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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

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Bivalent chromatin accommodates survivin and BRG1/SWI complex to activate DNA damage response in CD4+ cells

Chandrasekaran, Venkataragavan; Andersson, Karin M. E.; Erlandsson, Malin; Li, Shuxiang; Olsson, Torbjörn Nur; Garcia-Bonete, Maria-Jose; Malmhäll-Bah, Eric; Johansson, Pegah; Katona, Gergely; Bokarewa, Maria I.
Cell Commun Signal.
Sep 2024
10.1186/s12964-024-01814-4
Background: Bivalent regions of chromatin (BvCR) are characterized by trimethylated lysine 4 (H3K4me3) and lysine 27 on histone H3 (H3K27me3) deposition which aid gene expression control during cell differentiation. The role of BvCR in post-transcriptional DNA damage response remains unidentified. Oncoprotein survivin binds chromatin and mediates IFNγ effects in CD4+ cells. In this study, we explored the role of BvCR in DNA damage response of autoimmune CD4+ cells in rheumatoid arthritis (RA). Methods: We performed deep sequencing of the chromatin bound to survivin, H3K4me3, H3K27me3, and H3K27ac, in human CD4+ cells and identified BvCR, which possessed all three histone H3 modifications. Protein partners of survivin on chromatin were predicted by integration of motif enrichment analysis, computational machine-learning, and structural modeling, and validated experimentally by mass spectrometry and peptide binding array. Survivin-dependent change in BvCR and transcription of genes controlled by the BvCR was studied in CD4+ cells treated with survivin inhibitor, which revealed survivin-dependent biological processes. Finally, the survivin-dependent processes were mapped to the transcriptome of CD4+ cells in blood and in synovial tissue of RA patients and the effect of modern immunomodulating drugs on these processes was explored. Results: We identified that BvCR dominated by H3K4me3 (H3K4me3-BvCR) accommodated survivin within cis-regulatory elements of the genes controlling DNA damage. Inhibition of survivin or JAK-STAT signaling enhanced H3K4me3-BvCR dominance, which improved DNA damage recognition and arrested cell cycle progression in cultured CD4+ cells. Specifically, BvCR accommodating survivin aided sequence-specific anchoring of the BRG1/SWI chromatin-remodeling complex coordinating DNA damage response. Mapping survivin interactome to BRG1/SWI complex demonstrated interaction of survivin with the subunits anchoring the complex to chromatin. Co-expression of BRG1, survivin and IFNγ in CD4+ cells rendered complete deregulation of DNA damage response in RA. Such cells possessed strong ability of homing to RA joints. Immunomodulating drugs inhibited the anchoring subunits of BRG1/SWI complex, which affected arthritogenic profile of CD4+ cells. Conclusions: BvCR execute DNA damage control to maintain genome fidelity in IFN-activated CD4+ cells. Survivin anchors the BRG1/SWI complex to BvCR to repress DNA damage response. These results offer a platform for therapeutic interventions targeting survivin and BRG1/SWI complex in autoimmunity.

Discovery of a novel highly specific, fully human PSCA antibody and its application as an antibody-drug conjugate in prostate cancer

Chu, Xiaojie; Shin, Seungmin; Baek, Du-San; Zhang, Liyong; Conard, Alex; Shi, Megan; Kim, Ye-Jin; Adams, Cynthia; Hines, Maggie; Liu, Xianglei; Chen, Chuan; Sun, Zehua; Jelev, Dontcho V.; Mellors, John W.; Dimitrov, Dimiter S.; Li, Wei
mAbs.
Aug 2024
10.1080/19420862.2024.2387240
Prostate stem cell antigen (PSCA) is expressed in all stages of prostate cancer, including in advanced androgen-independent tumors and bone metastasis. PSCA may associate with prostate carcinogenesis and lineage plasticity in prostate cancer. PSCA is also a promising theranostic marker for a variety of other solid tumors, including pancreatic adenocarcinoma and renal cell carcinoma. Here, we identified a novel fully human PSCA antibody using phage display methodology. The structure-based affinity maturation yielded a high-affinity binder, F12, which is highly specific and does not bind to 6,000 human membrane proteins based on a membrane proteome array assay. F12 targets PSCA amino acids 63–69 as tested by the peptide scanning microarray, and it cross-reacts with the murine PSCA. IgG1 F12 efficiently internalizes into PSCA-expressing tumor cells. The antimitotic reagent monomethyl auristatin E (MMAE)-conjugated IgG1 F12 (ADC, F12-MMAE) exhibits dose-dependent efficacy and specificity in a human prostate cancer PC-3-PSCA xenograft NSG mouse model. This is a first reported ADC based on a fully human PSCA antibody and MMAE that is characterized in a xenograft murine model, which warrants further optimizations and investigations in additional preclinical tumor models, including prostate and other solid tumors.

Binding epitope for recognition of human TRPM4 channel by monoclonal antibody M4M

Wei, Shunhui; Behn, Julian; Poore, Charlene Priscilla; Low, See Wee; Nilius, Bernd; Fan, Hao; Liao, Ping
Sci Rep.
Nov 2022
10.1038/s41598-022-22077-4
Abstract Mouse monoclonal antibody M4M was recently designed to block human TRPM4 channel. The polypeptide for generating M4M is composed of peptide A1 between the transmembrane segment 5 (S5) and the pore, and a second peptide A2 between the pore and the transmembrane segment 6 (S6). Using peptide microarray, a 4-amino acid sequence EPGF within the A2 was identified to be the binding epitope for M4M. Substitution of EPGF with other amino acids greatly reduced binding affinity. Structural analysis of human TRPM4 structure indicates that EPGF is located externally to the channel pore. A1 is close to the EPGF binding epitope in space, albeit separated by a 37-amino acid peptide. Electrophysiological study reveals that M4M could block human TRPM4, but with no effect on rodent TRPM4 which shares a different amino acid sequence ERGS for the binding motif. Our results demonstrate that M4M is a specific inhibitor for human TRPM4.

Targeting FLT3 by new-generation antibody-drug-conjugate in combination with kinase inhibitors for treatment of AML

Roas, Maike; Vick, Binje; Kasper, Marc-André; Able, Marina; Polzer, Harald; Gerlach, Marcus; Kremmer, Elisabeth; Hecker, Judith S.; Schmitt, Saskia; Stengl, Andreas; Waller, Verena; Hohmann, Natascha; Festini, Moreno; Ludwig, Alexander Edmund; Rohrbacher, Lisa; Herold, Tobias; Subklewe, Marion; Götze, Katharina S.; Hackenberger, Christian P.R.; Schumacher, Dominik; Helma-Smets, Jonas; Jeremias, Irmela; Leonhardt, Heinrich; Spiekermann, Karsten
Aug 2022
10.1182/blood.2021015246
Fms like tyrosine kinase 3 (FLT3) is often overexpressed or constitutively activated by internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutations in acute myeloid leukemia (AML). Despite the use of receptor tyrosine kinase inhibitors (TKI) in FLT3-ITD positive AML, the prognosis of patients is still poor and further improvement of therapy is required. Targeting FLT3 independent of mutations by antibody‑drug‑conjugates (ADCs) is a promising strategy for AML therapy. Here, we report the development and preclinical characterization of a novel FLT3‑targeting ADC, 20D9-ADC, which was generated by applying the innovative P5 conjugation technology. In vitro, 20D9‑ADC mediated potent cytotoxicity to Ba/F3 cells expressing transgenic FLT3 or FLT3-ITD, to AML cell lines and to FLT3-ITD positive patient derived xenograft AML cells. In vivo, 20D9‑ADC treatment led to a significant tumor reduction and even durable complete remission in AML xenograft models. Further, 20D9‑ADC demonstrated no severe hematotoxicity in in vitro colony formation assays using concentrations that were cytotoxic in AML cell line treatment. The combination of 20D9-ADC with the TKI midostaurin showed strong synergy in vitro and in vivo, leading to reduction of aggressive AML cells below the detection limit. Our data indicate that targeting FLT3 with an advanced new-generation ADC is a promising and potent antileukemic strategy, especially when combined with FLT3-TKI in FLT3‑ITD positive AML.

A heterotypic assembly mechanism regulates CHIP E3 ligase activity

Das, Aniruddha; Thapa, Pankaj; Santiago, Ulises; Shanmugam, Nilesh; Banasiak, Katarzyna; Dąbrowska, Katarzyna; Nolte, Hendrik; Szulc, Natalia A; Gathungu, Rose M; Cysewski, Dominik; Krüger, Marcus; Dadlez, Michał; Nowotny, Marcin; Camacho, Carlos J; Hoppe, Thorsten; Pokrzywa, Wojciech
The EMBO Journal.
Aug 2022
10.15252/embj.2021109566
CHIP (C‐terminus of Hsc70‐interacting protein) and its worm ortholog CHN‐1 are E3 ubiquitin ligases that link the chaperone system with the ubiquitin‐proteasome system (UPS). CHN‐1 can cooperate with UFD‐2, another E3 ligase, to accelerate ubiquitin chain formation; however, the basis for the high processivity of this E3s set has remained obscure. Here, we studied the molecular mechanism and function of the CHN‐1–UFD‐2 complex in Caenorhabditis elegans. Our data show that UFD‐2 binding promotes the cooperation between CHN‐1 and ubiquitin‐conjugating E2 enzymes by stabilizing the CHN‐1 U‐box dimer. However, HSP70/HSP‐1 chaperone outcompetes UFD‐2 for CHN‐1 binding, thereby promoting a shift to the autoinhibited CHN‐1 state by acting on a conserved residue in its U‐box domain. The interaction with UFD‐2 enables CHN‐1 to efficiently ubiquitylate and regulate S‐adenosylhomocysteinase (AHCY‐1), a key enzyme in the S‐adenosylmethionine (SAM) regeneration cycle, which is essential for SAM‐dependent methylation. Our results define the molecular mechanism underlying the synergistic cooperation of CHN‐1 and UFD‐2 in substrate ubiquitylation.

IFx-Hu2.0 phase I first in human study for unresectable melanoma for an intralesional “in-situ vaccine” approach.

Markowitz, Joseph; Shamblott, Michael; Brohl, Andrew Scott; Sarnaik, Amod; Eroglu, Zeynep; Khushalani, Nikhil I.; Chen, Pei-Ling; De-Aquino, Deanryan B.; Sondak, Vernon K.; Tarhini, Ahmad A.; Kim, Youngchul; Pilon-Thomas, Shari
Jun 2022
10.1200/JCO.2022.40.16_suppl.e21542
e21542 Background: Many melanoma patients do not respond to anti-PD1 therapy due to lack of antigen specific responses. IFx-Hu2.0 (plasmid DNA encoding the streptococcal membrane protein, Emm55, contained within a cationic polymer) primes innate and antigen dependent responses in murine/equine melanoma models to produce an environment needed for checkpoint inhibitor efficacy. We describe the first in human study utilizing IFx-Hu2.0 in unresectable melanoma – NCT03655756. Methods: Melanoma patients (unresectable stage III/IV) had cutaneous lesions injected with IFx-Hu2.0 to test safety and feasibility. Patients were refractory to standard of care (anti-PD1, BRAF/MEK) or did not wish these treatments. 1-3 lesions (> 3 mm – 0.1 mg/0.2 mL) were injected, pre/post treatment biopsies obtained, and the primary endpoint of 5/6 patients without dose limiting toxicity (DLT) was assessed at 28 days. Retreatment was permitted. ≥2 lesions were needed: one for injection and uninjected lesion for biopsy. Tissue samples were analyzed for mRNA profiles, antigen responses (PEPperPRINT assay), and multiplex immunofluorescence (markers: CD3, CD8, FOXP3, PD1, PDL1, SOX10, DAPI). Results: The primary endpoint was met in 6 evaluable patients out of 7 enrolled. Observed toxicities included: G1-2 Injection site reactions – 5/7; G1 Bleeding – 1/7; G1-2 Pain – 2/7, G1 Lymphopenia – 1/7, G1 Pruritis – 1/7; with no ≥ G3 toxicities related to study drug observed. One G5 toxicity (Clostridium septicum infection 20 days post injection) was deemed unlikely related to study drug. 5/6 patients received 1 cycle prior to post-protocol immune-based therapy. One treatment naïve patient retreated once with IFx-Hu2.0 required no additional therapy > 9 months. Available paired tissue and plasma sampling revealed increased T cell infiltration into treated lesions, increase in IgM and IgG epitope recognition to melanoma associated antigens in the plasma (detected by PEPperPRINT assay), an increase in mRNA associated with innate immune responses in the injected lesion (CXCL13, LAG3, CXCL11, CXCL10, ICOS) and an adaptive immune response (IL-12, HLA-DRB5, WNT4, CD3D, Arg I) in uninjected lesions associated with downregulation of known melanoma antigens. Of 4 anti-PD1 refractory patients, three patients had clinical benefit to post-protocol retreatment with anti-PD1 based therapy (Stable Disease (SD) lasting > 2 years followed by surgical resection, Partial Response (PR) lasting > 9 months, PR subsequently surgical resected and rendered no evidence of disease). Conclusions: In this pilot study, intralesional IFx-Hu2.0 demonstrated a favorable safety profile. These data support encouraging immunological correlative responses and further study of IFx-Hu2.0 as a priming agent to enhance or restore sensitivity to immune checkpoint inhibitor therapy in melanoma. Clinical trial information: NCT03655756.

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