A novel thienopyrimidine analog, tph104, mediates immunogenic cell death in triple-negative breast cancer cells

Enhancing the tumor immunogenic microenvironment has been suggested to circumvent triple-negative breast cancer (TNBC) resistance and increase the efficacy of conventional chemo-therapy. Here, we report a novel chemotherapeutic compound, TPH104, which induces immuno-genic cell death in the TNBC cell line MDA-MB-231, by increasing the stimulatory capacity of dendritic cells (DCs), with an IC50 value of 140 nM. TPH104 (5 µM) significantly increased ATP levels in the supernatant and mobilized intracellular calreticulin to the plasma membrane in MDA-MB-231 cells, compared to cells incubated with the vehicle. Incubating MDA-MB-231 cells for 12 h with TPH104 (1–5 µM) significantly increased TNFα mRNA levels. The supernatants of dying MDAMB-231 cells incubated with TPH104 increased mouse bone marrow-derived DC maturation, the expression of MHCII and CD86 and the mRNA expression of TNFα, IL6 and IL12. Overall, these re-sults indicate that TPH104 induces immunogenic cell death in TNBC cells, in part, by activating DCs.