Structure-Based Design of Dual-Acting Compounds Targeting Adenosine A2A Receptor and Histone Deacetylase as Novel Tumor Immunotherapeutic Agents

Adenosine is an immunosuppressive factor in the tumor microenvironment mainly through activation of the A(2A) adenosine receptor (A(2A)R), which is a mechanism hijacked by tumors to escape immune surveillance. Small-molecule A(2A)R antagonists are being evaluated in clinical trials as immunotherapeutic agents, but their efficacy is limited as standalone therapies. To enhance the antitumor effects of A(2A)R antagonists, dual-acting compounds incorporating A(2A)R antagonism and histone deacetylase (HDAC) inhibitory actions were designed and synthesized, based on co-crystal structures of A(2A)R. Compound 24e (IHCH-3064) exhibited potent binding to A(2A)R (K-i = 2.2 nM) and selective inhibition of HDAC1 (IC50 = 80.2 nM), with good antiproliferative activity against tumor cell lines in vitro. Intraperitoneal administration of 24e (60 mg/kg, bid) inhibited mouse MC38 tumor growth with a tumor growth inhibition rate of 95.3%. These results showed that dual-acting compounds targeting A(2A)R and HDAC are potentially immunotherapeutic agents that are worth further exploring.

Automated summary

Adenosine serves as an immunosuppressive factor in the tumor microenvironment by activating the A(2A) adenosine receptor. Dual-acting compounds targeting A(2A)R and HDAC are potentially effective immunotherapeutic agents that show promising antitumor activity in vitro and in vivo.