STAT3 Inhibitors

Another therapy approach described to target the protection functions of the metastatic niche are STAT3 inhibitors. STAT3 is a transcription factor involved in cellular immunity, proliferation, apoptosis, and differentiation. In brain metastasis, the STAT3 inhibitor Legasil (Silibinin) reduced the immunosuppressive effect of astrocytes (Priego et al. 2018). Legasil prevents the activation these astrocytes which allows for CD8+ T cells to kill cancerous cells, a function previously suppressed by these cells allowing them to evade the immune response. With this STAT3 inhibitor activity, the protective function of the metastatic niche is eliminated. This therapy is systemic as STAT3 is a transcription factor prevalent throughout the body and inhibiting this transcription factor may affect healthy cells as well as cancerous ones. This treatment may also be better functioning within a more specific treatment targeted at solely tumor cells.