Synthesis, crystal structures, and antiglioma activity evaluation of two novel Ho(III) metal-organic complexes

Two new 3-D metal-organic frameworks, {[Ho(H2O)((CO2)(3)C24H15)]center dot 7H(2)O}(n) (1) and {[Ho-3(H2O)(3)((CO2)(3)C18H12N)(3)]center dot 7H(2)O}(n) (2), have been prepared under solvothermal or hydrothermal conditions by using two C-3-symmetrical organic ligands 4,4 ',4 "-benzene-1,3,5-triyl-tri-benzoic acid (H3BTB) and 4,4 ',4 "-nitrilotribenzoic acid (H3NTB). The in vitro anticancer activities of 1 and 2 were detected on human glioma cell line U251. The MTT assay and the IC50 values indicated that, even though both of these two compounds have anticancer ability, 1 shows a stronger inhibitory effect on cancer proliferation. The Annexin V-FITC/PI assay confirmed that 1 inhibits U251 cells proliferation via apoptosis. This apoptotic effect was mediated by increased ROS and activation of caspase-3 and caspase-8, which is determined by flow cytometer and western blot. We then verified that the anticancer effect of the two new synthesized compounds could be abolished by ROS inhibitor NAC. [GRAPHICS] .