PPM-3

PPM-3 potently inhibits ERK5 kinase activity with an IC₅₀ of 62.4 nM^[1].
When tested in a cell-free system, PPM-3 (0.5 μM) exhibits excellent kinase selectivity for ERK5 compared with more than 300 other kinases^[1].
PPM-3 effectively reduces ERK5 protein levels in an initial degradation activity comparison assay in A375 cells, with a DC₅₀ of approximately 17 nM, and exhibits the highest ERK5 degradation activity among PPM-3, PPM-4 and PPM-5^[1].
PPM-3 (6-500 nM; 12 h) selectively degrades ERK5 but does not degrade LRRK2, BRD4 or DCLK1 in A375 melanoma cells^[1].
PPM-3 (200 nM; 12 h) induces ERK5 degradation in A375 cells. Pre-incubation with MG132 (HY-13259) (1 μM) or MLN4924 (HY-70062) (1 μM) for 1 h blocks the downregulation of ERK5, supporting that PPM-3-mediated ERK5 degradation depends on the proteasome/E3 ubiquitination-related pathway^[1].

PPM-3 (12 h) is a potent ERK5 degrader active against six cancer cell lines, with DC₅₀ values ranging from 5.6 nM (HCT116) to 41.4 nM (A375) and a maximum degradation efficiency of 86.7-94.7%^[1].
PPM-3 (72 h) does not reduce the cell viability of H1975, HepG2, MDA-MB-231, PC-3, HCT116, or A375 cancer cells^[1].
PPM-3 (0.01-1 μM; 24 h) does not affect the migration of A375 or HCT116 cancer cells^[1].
PPM-3 (10-1000 nM; 24 h) does not reduce ERK5 mRNA levels in A375 cells, indicating that the decrease in ERK5 protein is not caused by the downregulation of ERK5 transcription^[1].
PPM-3 (6-500 nM; 12 h) selectively degrades ERK5 in A375 cells, with no significant effect on the protein levels of LRRK2, BRD4, and DCLK1^[1].
PPM-3 (200 nM) begins to induce ERK5 degradation in A375 cells within 2-4 h, reaches its maximum degradation effect at 12 h, and this effect is maintained for at least 72 h^[1].
PPM-3 (12 h) effectively degrades ERK5 in H1975, HepG2, MDA-MB-231, PC-3, HCT116, and A375 cells, with DC₅₀ values of 11.5, 13.7, 22.7, 23.5, 5.6, and 41.4 nM, and DC_max values of 94.7%, 92.7%, 86.7%, 89.4%, 88.9%, and 91.4%, respectively^[1].
PPM-3 (72 h) exhibits no significant direct antiproliferative effect within the concentration range that effectively degrades ERK5 in H1975, HepG2, MDA-MB-231, PC-3, HCT116, and A375 cells^[1].
Combined exposure to PPM-3 (200 nM; 72 h) with Dabrafenib (HY-14660), Vemurafenib (HY-12057), Trametinib (HY-10999), Mirdametinib (HY-10254), or GDC-0994 (HY-15947) does not significantly alter the effects of these RAF, MEK1/2, or ERK1/2 inhibitors on the viability of A375/HCT116 cells^[1].
PPM-3 (0.5 μM) exerts no significant effect on the colony formation of A375/HCT116 cells grown directly under normal culture conditions. However, conditioned medium from M0 or M2 macrophages treated with PPM-3 reduces tumor cell colony formation and attenuates the promoting effect of M2-conditioned medium on the colony growth of A375 and HCT116 cells^[1].

PPM-3 (0.5 μM; pre-incubation for 0.5 h followed by the addition of 1 μg/mL LPS (HY-D1056) for 24 h) consistently and effectively reduces ERK5 and decreases LPS-induced IL-6 and IL-10 release in THP-1 cells^[1].

PPM-3 (0.5 μM; 48 h) induces morphological changes in macrophages in PMA (HY-18739)-induced THP-1-derived macrophages, and reduces the proportion of CD206-positive macrophages from 53.4% in the control group to 41.3%, supporting its inhibitory effect on M2 macrophage differentiation^[1].