Pyruvate Kinase M2 in Blood Circulation Facilitates Tumor Growth by Promoting Angiogenesis [Molecular Bases of Disease]

July 28th, 2014 by Li, L., Zhang, Y., Qiao, J., Yang, J. J., Liu, Z.-R.

It is long known that pyruvate kinase isoform M2 (PKM2) is released into the circulation of cancer patients. The PKM2 levels in patient circulation have been suggested as a diagnostic marker for many types of cancers. However, it is not known how the PKM2 is released to blood circulation, and whether the circulating PKM2 has any physiological function(s) in tumor progression. In this report, we demonstrate that PKM2 in the blood circulation facilitates tumor growth by promoting tumor angiogenesis. Our experiments show that PKM2 promotes tumor angiogenesis by increasing endothelial cell proliferation, migration, and cell-ECM adhesions. Only the dimeric PKM2 possess the activity in promoting tumor angiogenesis, which is consistent with the observations that the PKM2 in circulation of cancer patients is a dimer form.