Niacin Ester Derivative of Brefeldin A as a Potential Dual-Target Arf1/BMX Inhibitor for Bladder Cancer

Bladder cancer is a common malignancy known for its high recurrence rate and poor survival rate. New strategies are urgently needed to reduce recurrence and improve prognosis. Arf1 and BMX are potential targets associated with the prognosis of bladder cancer. In this study, niacin ester derivatives of brefeldin A were synthesized by introducing nicotinic acid moieties at the 4-OH and 7-OH positions. Notably, the 4-monoester derivative, CHNQD-01228 (2), could significantly inhibit the proliferation of T24 cells (IC₅₀ = 0.22 μM) in a time-dependent manner. Furthermore, it dose-dependently inhibited T24 cell migration and colony formation, induced G1 phase arrest, and triggered apoptosis. Based on molecular modeling, CHNQD-01228 was evaluated to exhibit high binding affinity toward both Arf1 and BMX proteins. Further verification was conducted using cellular thermal shift assays and drug affinity responsive target stability assays. It suppressed the AKT/p-AKT and STAT3/p-STAT3 signaling pathways by targeting BMX in T24 cells, eliminated bladder cancer stem cells, and activated antitumor immunity via Arf1 inhibition. In vivo data further demonstrated that the dual-target inhibitor exhibited a potential antitumor efficacy against MB49 allograft tumors (TGI = 51.0%) and thus represents a promising therapeutic strategy for bladder cancer.