Antitumor activity of the novel BTK inhibitor TG-1701 is associated with disruption of Ikaros signaling in patients with B-cell non-Hodgkin lymphoma.Clin Cancer Res 2 Dec 2021, . Epub 22 Sep 2021
Purpose: Despite the remarkable activity of BTK inhibitors (BTKi) in relapsed B-cell non-Hodgkin lymphoma (B-NHL), no clinically-relevant biomarker has been associated to these agents so far. The relevance of phosphoproteomic profiling for the early identification of BTKi responders remains underexplored.
Experimental design: A set of six clinical samples from an ongoing phase 1 trial dosing chronic lymphocytic leukemia (CLL) patients with TG-1701, a novel irreversible and highly specific BTKi, were characterized by phosphoproteomic and RNA-seq analysis. The activity of TG-1701 was evaluated in a panel of eleven B-NHL cell lines and mouse xenografts, including two NFκB- and BTKC481S-driven BTKi resistant models. Biomarker validation and signal transduction analysis were conducted through real-time PCR, western blot, immunostaining and gene knock-out (KO) experiments.
Results: A non-supervised, phosphoproteomic-based clustering did match the early clinical outcomes of CLL patients and separated a group of "early-responders" from a group of "late-responders". This clustering was based on a selected list of 96 phosphosites with Ikaros-pSer442/445 as a potential biomarker for TG-1701 efficacy. TG-1701 treatment was further shown to blunt Ikaros gene signature, including YES1 and MYC, in early-responder patients as well as in BTKi-sensitive B-NHL cell lines and xenografts. In contrast, Ikaros nuclear activity and signaling remained unaffected by the drug in vitro and in vivo, in late-responder patients and in BTKC481S, BTKKO and non-canonical NFκB models.
Conclusions: These data validate phosphoproteomic as a valuable tool for the early detection of response to BTK inhibition in the clinic, and for the determination of drug mechanism of action.More information
JAK2-STAT Epigenetically Regulates Tolerized Genes in Monocytes in the First Encounter With Gram-Negative Bacterial Endotoxins in SepsisFront. Immunol. 12:734652. https://doi.org/10.3389/fimmu.2021.734652 17 Nov 2021, . Epub 17 Nov 2021
Microbial challenges, such as widespread bacterial infection in sepsis, induce endotoxin tolerance, a state of hyporesponsiveness to subsequent infections. The participation of DNA methylation in this process is poorly known. In this study, we perform integrated analysis of DNA methylation and transcriptional changes following in vitro exposure to gram-negative bacterial lipopolysaccharide, together with analysis of ex vivo monocytes from septic patients. We identify TET2-mediated demethylation and transcriptional activation of inflammation-related genes that is specific to toll-like receptor stimulation.
Changes also involve phosphorylation of STAT1, STAT3 and STAT5, elements of the JAK2 pathway. JAK2 pathway inhibition impairs the activation of tolerized genes on the first encounter with lipopolysaccharide. We then confirm the implication of the JAK2-STAT pathway in the aberrant DNA methylome of patients with sepsis caused by gram-negative bacteria. Finally, JAK2 inhibition in monocytes partially recapitulates the expression changes produced in the immunosuppressive cellular state acquired by monocytes from gram-negative sepsis, as described by single cell-RNA-sequencing. Our study evidences both the crucial role the JAK2-STAT pathway in epigenetic regulation and initial response of the tolerized genes to gram-negative bacterial endotoxins and provides a pharmacological target to prevent exacerbated responses.
Mixed-Up Sugars: Glycosyltransferase Cross-Reactivity in Cancerous Tissues and Their Therapeutic Targeting.Chembiochem 2 Nov 2021, . Epub 2 Nov 2021
The main categories of glycan changes in cancer are: (1) decreased expression of histo-blood group A and/or B antigens and increased Lewis-related antigens, (2) appearance of cryptic antigens, such as Tn and T, (3) emergence of genetically incompatible glycans, such as A antigen expressed in tumors of individuals of group B or O and heterophilic expression of Forssman antigen (FORS1), and (4) appearance of neoglycans. This review focuses on the expression of genetically incompatible A/B/FORS1 antigens in cancer. Several possible molecular mechanisms are exemplified, including missense mutations that alter the sugar specificity of A and B glycosyltransferases (AT and BT, respectively), restoration of the correct codon reading frame of O alleles, and modification of acceptor specificity of AT to synthesize the FORS1 antigen by missense mutations and/or altered splicing. Taking advantage of pre-existing natural immunity, the potential uses of these glycans for immunotherapeutic targeting will also be discussed.More information
The transcribed ultraconserved region uc.160+ enhances processing and A-to-I editing of the miR-376 cluster: hypermethylation improves glioma prognosis.Mol Oncol 19 Oct 2021, . Epub 19 Oct 2021
Transcribed ultraconserved regions (T-UCRs) are noncoding RNAs derived from DNA sequences that are entirely conserved across species. Their expression is altered in many tumor types, and, although a role for T-UCRs as regulators of gene expression has been proposed, their functions remain largely unknown. Herein, we describe the epigenetic silencing of the uc.160+ T-UCR in gliomas and mechanistically define a novel RNA-RNA regulatory network in which uc.160+ modulates the biogenesis of several members of the miR-376 cluster. This includes the positive regulation of primary microRNA (pri-miRNA) cleavage and an enhanced A-to-I editing on its mature sequence. As a consequence, the expression of uc.160+ affects the downstream, miR-376-regulated genes, including the transcriptional coregulators RING1 and YY1-binding protein (RYBP) and forkhead box P2 (FOXP2). Finally, we elucidate the clinical impact of our findings, showing that hypermethylation of the uc.160+ CpG island is an independent prognostic factor associated with better overall survival in lower-grade gliomas, highlighting the importance of T-UCRs in cancer pathophysiology.More information