Action of copper(II) complex with β-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death

Abstract

This work reports the biological evaluation of a copper complex of the type [Cu(O–O)(N–N)ClO4], in which O–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N–N = 1,10-phenanthroline (phen), whose generic name is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation was determined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression was detected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively, Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactive oxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumor activity with IC50s values of 7.4 μM against Sarcoma 180 and 26.4 against murine myoblast cells, displaying selectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) generation was observed, which may be related to the action mechanism of the complex. The complex CBP-01 may induce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not able to recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagy dysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcoming the drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtained with CBP-01 show promising effects on cancer cells.

Keywords

• Copper complex
• Cytotoxicity
• Apoptosis
• Cell cycle
• ROS