Figure 4.

Hypoxic tumor cell distribution relative to blood vessels. (A) Representative images of CD31 antibody staining for blood vessel endothelium in GFP-MDA-MB-231-5HREODD-mCherry tumor frozen sections showing the hypoxic cells are found both away from and adjacent to blood vessels. Green=GFP hypoxia reporter in normoxia; Red=mCherry hypoxia reporter in hypoxia, Gray=CD31. (B and C) Representative images of tumor frozen sections (B) and ex vivo imaging (C) to show perfused blood vessels (green) relative to hypoxic cell distribution (red) in MDA-MB-231-5HREODD-mCherry derived tumors that were IV injected with lectin (green) before sacrificing. In areas of flowing blood vessels the hypoxic tumor cells are closely associated with a subset of blood vessels. Yellow boxes indicate regions shown at high magnification. In this tumor, tumor cell does not express the GFP volume marker so as to prevent overlap with FITC lectin signal. For B and C, Green =FITC lectin stained blood vessels, red = mCherry hypoxia, Gray=DAPI.