MAO A/HSP90-IN-2 (compound 4-C) is a dual inhibitor of HSP90and MAO A with the IC₅₀ values of 0.016 and 4.58 μM, respectively. MAO A/HSP90-IN-2 increases HSP70 expression and reduces HER2 and phospho-Akt expression, and decreases IFN-γ induced PD-L1 expression in GL26 cells. MAO A/HSP90-IN-2 inhibits the growth of Temozolomide (HY-17364) -sensitive and -resistant GBM cells, colon cancer, leukemia, non-small cell lung and other cancers, and has potential to inhibit tumor immune escape^[1].