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. 2012 Nov 30;7(11):e50860. doi: 10.1371/journal.pone.0050860

Figure 2. In vitro characterization of HS680 in hypoxic and normoxic tumor cells.

Figure 2

A, Binding of HS680 to hypoxic and normoxic HeLa cells was shown with fluorescence microcopy. Cells labeled with the control agent cultured under hypoxic conditions provided a negative control. Blocking of HS680 binding by pre-incubating the hypoxic cells with AZ is shown in lower right panel. The images of cells cultured with control agent and HS680 with AZ blocking under normoxic conditions were similar to the images of HS680 cultured at nomoxic conditions, and therefore they were not shown. B, Representative histograms of HS680 binding to normoxic and hypoxic HeLa cells by flow cytometry with AZ blocking in hypoxic cells. C, Flow cytometry quantifications of binding of HS680 and control agent to normoxic and hypoxic HT-29, HeLa, HCT-116, and MDA-MB-231 cells with or without AZ blocking in hypoxic cells. D, The disassociation constant (Kd) of HS680 was determined in HeLa cells by flow cytometry to be 8.3 nM.