Novel di-n-butyltin(IV) derivatives: Synthesis, high levels of cytotoxicity in tumor cells and the induction of apoptosis in KB cancer cells.

Two classes of dibutyltin(IV) hydroxamates complexes, formulated as the mononuclear mixed-ligand diorganotin(IV) complex [(n)Bu(2)Sn(HL)Cl] a and the tetranuclear (n)Bu(4)Sn(2)(HL)(2)(L)b were fully characterized. X-ray diffraction analyses were also carried out for the representative complexes (n)Bu(2)Sn(2,6-F(2)C(6)H(3)C(O)NHO)Cl and (n)Bu(4)Sn(2){3-BrC(6)H(4)C(O)NHO}(2){3-BrC(6)H(4)C(NO)O}. The cytotoxicity of all compounds was tested by MTT and SRB assays against three human tumor cell lines HL-60, BGC-823 and KB. 1b and 4a have been shown to be more potent antitumor agents than other compounds and cisplatin. Annexin V FITC-PI assay was consistent with the MTT results. Cell cycle assay results indicated that KB cells displayed an arrest in the G(0)/G(1) phase and a decrease of S phase of the cell cycle at the low concentrations of 1b, 4a.