ABSTRACT
We investigated the antineoplastic activities of a previously reported copper (II) coordination compound, [Cu(BMPA)Cl2]CH3OH (1), and a new compound, [Cu(HBPA)Cl2]H2O (2), where BMPA is bis(pyridin-2-ylmethyl)amine and HBPA is (2-hydroxybenzyl)(2-pyridylmethyl)amine, using various cellular models of human leukemia (THP-1, U937, HL60, Molt-4, JURKAT) and human colon cancer (COLO 205), as well as a murine highly metastatic melanoma (B16-F10) cell line. Compound (2) was characterized using several physical and chemical techniques, including X-ray diffraction studies. The IC50 values of the copper coordination complexes in the human leukemia cell lines ranged from 87.63 ± 1.02 to ≥400 µM at high cell concentrations and from 19.17 ± 1.06 to 97.67 ± 1.23 µM at low cell concentrations. Both compounds induced cell death, which was determined by cell cycle analyses and phosphatidylserine exposure studies. THP-1 cells released cytochrome c to the cytoplasm 12 h after treatment with 400 µM of compound (2). To evaluate the apoptosis pathway induced by compound (2), we measured the activities of initiator caspases 8 and 9 and executioner caspases 3 and 6. The results were suggestive of the activation of both intrinsic and extrinsic apoptosis pathways. To investigate the activities of the compounds in vivo, we selected two sensitive cell lines from leukemia (THP-1) and solid tumor (B16-F10) lineages. BALB/c nude bearing THP-1 tumors treated with 12 mg·kg(-1) of compound (2) showed a 92.4% inhibition of tumor growth compared with the control group.
