Discovery of Small Molecules as Multi-Toll-like Receptor Agonists with Proinflammatory and Anticancer Activities

Therapies based on activation of multiple Toll-like receptors (TLRs) may offer superior therapeutic profiles than that of single TLR activation. To discover new small molecules that could activate multiple TLRs, we performed a cell-based high-throughput screening of a small-molecule library based on TLR3-mediated NF-κB activation. Subsequent structural optimization and counterscreening of other TLRs produced the first small molecule 17e (CU-CPT17e) capable of simultaneously activating TLRs 3, 8, and 9. Biochemical studies demonstrated that 17e could induce a strong immune response via the production of various cytokines in human monocytic THP-1 cells. Furthermore, 17e inhibited the proliferation of HeLa cancer cells by triggering apoptosis and arresting the cell cycle at the S phase. These results showcase potential therapeutic applications of 17e in both vaccine adjuvants and anticancer therapies based on multi-TLR activation.