Discovery of 9-arylamino-2,3-dihydro-[1,4]dioxino[2,3-g]quinoline-8-carbonitriles: Potent inducers of immunogenic cell death via colchicine site-targeted microtubule polymerization inhibition.

A series of microtubule polymerization inhibitors that target the colchicine site on the basis of a new scaffold have been developed. Among them, compound 17 exhibited outstanding comprehensive antitumor efficacy against a panel of cancer cell lines (with an average IC50 value of 17.7 nM). Paclitaxel resistance was successfully overcome in a xenograft model in which paclitaxel-resistant A549/TxR cells were used in BALB/c nude mice, as expected. Moreover, the outstanding antitumor efficacy of compound 17 is attributed not only to its chemical toxicity but also to its ability to induce immunogenic cell death (ICD). In vitro, compound 17 potently induced immunogenic cell death in A549 cells at 80 nM, outperforming the reference drug doxorubicin at 200 nM. In the C57BL/6 mouse LLC model, compound 17 achieved a remarkable 81.6% tumor growth inhibition rate and effectively promoted the infiltration of CD4+ and CD8+ T cells into the tumor microenvironment and increased the levels of multiple serum immune factors. These results highlight 17 as a promising candidate for the development of novel chemoimmunotherapy strategies.