FIGURE 6.

PKM2 affects endothelial tube formation, migration, and extracellular matrix attachment. Shown are representative light microscopic images of endothelial tubers formed by HUVECs in the presence of rPKM2, rPKM2 + FBP, rPKM1, and buffer saline (A) or quantitative analyses of the branch points in the formed HUVEC tubes (B). The quantification was the mean of branch point counting of four randomly selected fields from each slide and with five repeating experiments (slides). C and D, cell proliferation (C) and migration (D) of HUVECs in the presence of rPKM2, rPKM2 + FBP, rPKM1, and buffer saline were analyzed by a commercial BrdU proliferation kit and Boyden chamber assay, respectively. The cell proliferation and migration assays are presented as relative proliferation (C) or relative migration (D) by defining the proliferation of buffer saline-treated cells as 100% and cell migration of rPKM2-treated cells as 100%. E and F, cell attachment of HUVECs to cell culture plates on which rPKM2, rPKM1, or BSA was coated (E) or fibronectin or vitronectin was coated, and the indicated proteins were added to the culture medium (F). The cell attachments are presented as relative attachment by defining the cell attachment in the plate on which rPKM2 was coated as 100% in E or buffer saline was added to the culture medium as 100% in F. In A–D, buffer saline is a control. The p values are presented by * (p ≤ 0.05), *** (p ≤ 0.005), or NS (statistically insignificant; p >0.05) and were calculated using unpaired two-tailed Student's t test. The error bars in B–F represent the S.D. from five repeating experiments.