The central role of Src in
tumor progression and
metastasis has validated it as an attractive therapeutic target for the treatment of human
breast cancer. The aim of this study was to identify potential
Src kinase inhibitor, explore its activity, and mechanism of action in human
breast cancer. A strategy integrating focused combinatorial library design, virtual screening, chemical synthesis, and high-throughput screening was adopted and a novel 6-hydrazinopurine-based inhibitor of
c-Src kinase PH006 was obtained. The
kinase enzymatic activities were measured by
enzyme-linked
immunosorbent assay. The binding mode between PH006 and Src was profiled by surface plasmon resonance approach and molecular simulation. The anti-proliferative activity was evaluated by Sulforhodamin B (SRB) and Colony formation. The anti-invasion and anti-migration activities were assessed by trans-well and wound healing assay. Results indicated that PH006 was an
ATP-competitive Src inhibitor, which selectively inhibited c-Src with an IC₅₀ of 0.38 μM among a panel of 14 diverse
tyrosine kinases. PH006 potently inhibited c-Src phosphorylation and c-Src-dependent signal transduction, resulting in inhibition of cell proliferation, migration, and invasion in human
breast cancer MDA-MB-231 cells. Further study demonstrated that the anti-proliferative activity of PH006 was ascribed to its capability to arrest cells in G1 phase, while its anti-motility activity was related to suppression of MMP2/9 and HGF secretion. Moreover, PH006 exhibited potent activity against
tumor growth as well as
metastasis of human
breast cancer MDA-MB-435 xenograft beard in nude mice, which was accompanied with reduced Src/FAK signaling in
tumor tissue. Taken together, PH006 is a novel selective inhibitor of c-Src and possesses potent activity against
breast cancer growth and
metastasis, which could be potentially developed as a lead candidate against breast
cancers with elevated
Src tyrosine kinase activity.