MMP9 and lung cancer: We previously reported that two polypyridyl Ru complexes, Ru-SC and Ru-bpy, having structures shown in Figure 1, are potent inhibitors of MMP2 and MMP9 and reduced MMP9 expression levels in lung cancer cells lysates [13,26], whereas Ru-bpy and Ru-NitroIm (structure shown in Figure 1) decreased the expression level of MMP9 mRNA under hypoxic conditions [10].