Effective inhibitory activity against MCF-7, A549 and HepG2 cancer cells by a phosphomolybdate based hybrid solid

A novel Strandberg type polyoxomolybdate based organic-inorganic hybrid solid, [{4,4'-H₂bpy}{4,4'-Hbpy}₂{H₂P₂Mo₅O₂₃}]·5H₂O (1) has been synthesized and structurally characterized by the single crystal X-ray diffraction technique. The structure consists of a discrete type phosphomolybdate cluster, [H₂P₂Mo₅O₂₃]^4-, connected with three protonated 4,4'-bipyridine molecules by strong hydrogen bonding interactions. The In vitro anti-tumoral activity of compound (1) was tested against human breast cancer (MCF-7), human lung cancer (A549) and human liver cancer (HepG2) cells. The Strandberg type cluster was used against the MCF-7 and A549 cancer cells for the first time hitherto. It shows considerable inhibitory effect with IC₅₀ values of 33.79 μmol L^-1, 25.17 μmol L^-1, and 32.11 μmol L^-1 against HepG2, A549 and MCF-7 respectively. The anti-tumoral activity of 1 was also found to be comparable with that of a routinely used chemotherapeutic agent, methotrexate (MTX), with an IC₅₀ value of 42.03 μmol L^-1 for HepG2, 26.93 μmol L^-1 for A549 and 49.79 μmol L^-1 for MCF-7. The anti-proliferation activity is mediated by the arrest of the A549 and HepG2 cells in the S phase and MCF-7 in the G2/M phase of the cell cycle as suggested by flow cytometry. Results suggest that apoptosis and necrosis pathways ultimately lead to the death of the cancer cells.