Impaired angiogenesis and tumor development by inhibition of the mitotic kinesin Eg5

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• Kinesin motor proteins are crucial for eukaryotic cellular functions, including mitosis, migration, and intracellular transport.
• Inhibitors of the mitotic kinesin KIF11/Eg5 show promise as anti-cancer agents.
• Vascular endothelial growth factor-A (VEGF-A) stimulates angiogenesis, a process vital for tumor growth.

Purpose of the Study:

• To investigate the role of mitotic kinesins, including Eg5 and KIF20A/Mklp2, in VEGF-A-induced angiogenesis.
• To evaluate the therapeutic potential of targeting these kinesins in cancer by examining their effects on endothelial cells and tumor angiogenesis.

Main Methods:

• Expression analysis of kinesin genes in response to VEGF-A stimulation.
• In vitro assays to assess the impact of Eg5 inhibition on endothelial cell proliferation and migration.
• Inhibition studies in aortic ring cultures and in vivo models (zebrafish, chick embryos, and experimental tumors) to evaluate vascular outgrowth and tumor angiogenesis.

Main Results:

• VEGF-A stimulation induced Eg5 and KIF20A/Mklp2 expression, particularly in lymphoblasts and endothelial cells.
• Chemical blockade of Eg5 inhibited endothelial cell proliferation and migration in vitro.
• Eg5 and Mklp2 inhibition impaired mitosis-independent vascular outgrowth in aortic ring cultures.
• Interference with KIF11/Eg5 function led to developmental and vascular defects in embryos and potent inhibition of tumor angiogenesis in vivo.

Conclusions:

• Kinesin inhibitors targeting Eg5 and Mklp2 represent a novel therapeutic strategy for cancer by disrupting tumor angiogenesis.
• Impairing endothelial cell function is a key mechanism of action for these kinesin inhibitors, complementing their effects on tumor cell proliferation.