Superior anti-DLBCL efficacy of novel organic arsenical Z2-A-Z2 through ROS-mediated apoptosis and critical NF-κB/IκBα signaling pathway inhibition

Abstract Objective Diffuse large B-cell lymphoma (DLBCL) often resists therapy due to aberrant activation of NF-κB signaling pathway. We synthesized and evaluated Z2-A-Z2, a novel organic arsenical, hypothesized to target this survival pathway, aiming to assess its efficacy and mechanism against DLBCL. Materials and methods The novel compound Z2-A-Z2 was synthesized and verified by 1 H CMR, 13 C CMR, and high-resolution mass spectrometry. Its anti-proliferative activity was assessed in GCB- and ABC-subtype DLBCL cell lines and normal peripheral blood mononuclear cells (PBMCs) using CCK-8 assays. Mechanisms were elucidated through flow cytometry (apoptosis, ROS, ΔΨm), Western blot (apoptotic and NF-κB pathway proteins), and enzyme activity assays. The causal role of ROS was confirmed by N-Acetylcysteine rescue (NAC) experiments, and the criticality of NF-κB inhibition was validated using p65 overexpression and pharmacological inhibition. Efficacy and safety were ultimately verified in SU-DHL-6 and U2932 xenograft model. Results Z2-A-Z2 demonstrated potent and selective anti-proliferative activity against DLBCL cell lines, achieving an average IC₅₀ of approximately 1.1 µM. This efficacy was 3- to 6-fold superior to arsenic trioxide (ATO), while exhibiting minimal cytotoxicity toward normal PBMCs and B cells. Mechanistically, Z2-A-Z2 induced profound mitochondrial-mediated apoptosis and G2/M cell cycle arrest through a unique dual action of simultaneously triggering catastrophic oxidative stress and critically suppressing the pro-survival NF-κB/IκBα signaling axis. Further investigation revealed a bidirectional regulation where ROS acts upstream to suppress p65 activity, while p65 in turn modulates drug-induced ROS generation. In vivo studies further validated these findings, showing that Z2-A-Z2 resulted in a robust suppression of tumor growth in a xenograft model, accompanied by diminished NF-κB/IκBα activity and increased apoptosis, alongside an excellent safety profile. Conclusion Z2-A-Z2 is a promising organic arsenical with superior efficacy and safety over ATO. Its unique dual-action strategy of simultaneously inducing oxidative stress and critically inhibiting the NF-κB/IκBα signaling axis, positioning it as a strong clinical candidate for effectively treating DLBCL.