ZT55 (JAK inhibitor ZT55) is a novel potent, highly-selective tyrosine kinase JAK2 inhibitor with IC50 of 31 nM.
ZT55 displays no significant activity against JAK1/3 (IC50>10 uM).
ZT55 exhibits potent effects on the cellular JAK-STAT pathway, inhibiting tyrosine phosphorylation in JAK2V617F and downstream STAT3/5 transcription factors.
ZT55 inhibits the proliferation of the JAK2V617F-expressing HEL cell line, leading to cell cycle arrest at the G2/M phase and induction of caspase-dependent apoptosis.
ZT55 significantly suppressed the growth of HEL xenograft tumors in vivo, blocks erythroid colony formation of peripheral blood hematopoietic progenitors from patients carrying the JAK2V617F mutation.
