Journal: Journal for immunotherapy of cancer
Article Title: Cbl-b inhibitor NX-1607 activates MAPK/ERK signaling pathway and enhances T-cell activation.
doi: 10.1136/jitc-2024-011180
Figure Lengend Snippet: Figure 1 Impact of NX-1607 on Cbl-b activity and T-cell activation/proliferation. (a) The chemical structure of the Cbl-b inhibitor NX-1607. (b) Illustration of the HTRF assay showing Cbl-b activity inhibition by a Cbl-b inhibitor, involving SRC, UBE1 (E1), UbcH5b (E2), Cbl-b (E3), ubiquitin, and ATP. Image was created with BioRender.com, with permission. (c) IC50 values of NX-1607 for inhibiting Cbl-b activity were determined using HTRF assays, with data from two biological replicates presented as mean±SEM. (d) NX-1607 increases p-PLCγ1-Y783 and p-HCLS1-Y397 in Jurkat T cells in a concentration-dependent manner. Cells were treated with NX-1607 or plate-bound anti-CD3 for 6 hours, followed by western blot analysis. (e) Histograms showing CD69 expression in Jurkat T and human primary CD3+ T cells after NX-1607 treatment, with or without CD3 stimulation. Cells were left untreated or pretreated with 2 μM NX-1607 for 1 hour, then exposed to plate-bound anti-CD3 for an additional 24 hours and analyzed by flow cytometry. (f) Mean fluorescence intensity quantification of CD69 in T cells in (e), based on three independent experiments, presented as mean±SD, with one-way analysis of variance analysis (***p<0.001). (g) IL2 and IFNG messenger RNA levels in primary human CD3+ T cells after 2 μM NX-1607 treatment, with or without anti-CD3 stimulation (2 µg/ mL) for 48 hours. Data from three independent experiments, presented as mean±SD, with t-test analysis (***p<0.001, **p<0.01). (h) The proliferative effects of NX-1607 were assessed in primary human CD3+, CD4+, and CD8+ T cells, with or without anti-CD3 stimulation (2 µg/mL) for 72 hours. The upper panel presents OD450 readings from primary human CD3+, CD4+, and CD8+ T- cell populations, while the lower panel illustrates the corresponding cell counts for each T-cell subset. Data obtained from three independent experiments (mean±SD, t-test) (*p<0.05, **p<0.01, ***p<0.001). Cbl-b, casitas B lymphoma-b; HTRF, homogeneous time-resolved fluorescence; IC50, half-maximal inhibitory concentration.
Article Snippet: Detection of phosphoPLCγ1 was performed by incubating the samples with a rabbit antibody specific to phospho- PLCγ1 (#14008, CST) for 2 hours at room temperature, followed by a 1- hour incubation with Goat anti- Rabbit Alexa Fluor 488 (#A11008, Invitrogen) at room temperature.
Techniques: Activity Assay, Activation Assay, HTRF Assay, Inhibition, Ubiquitin Proteomics, Concentration Assay, Western Blot, Expressing, Flow Cytometry, Fluorescence