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: 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 ) IC 50 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; IC 50 , half-maximal inhibitory concentration.
Article Snippet: Primary antibodies were purchased from Cell Signaling Technology (Danvers, Massachusetts, USA) against the following: p-PLCγ1 (#14008), PLCγ1 (#2822), Cbl-b (#9498), p-MEK1/2 (#9154), MEK1/2 (#4694), p-ERK1/2 (#4370), ERK1/2 (#9102), p-PKCθ (#9377), PKCθ (#13643), p-IKKα/β (#2697), IKKα (#2682), IKKβ (#2370), p-IκBα (#9246), IκBα (#9242), p-MKK3/MKK6 (#9236), MKK3 (#8535), p-P38 MAPK (#9211), P38-MAPK (#9212), p-Akt (#13 038S), Akt (#4691), p-S6 (#4858), S6 (#2217), VAV1 (#4657), and JNK (#9252).
Techniques: Activity Assay, Activation Assay, HTRF Assay, Inhibition, Ubiquitin Proteomics, Concentration Assay, Western Blot, Expressing, Flow Cytometry, Fluorescence