Six
complexes with the general formula [Cu(acylthioureato)(PPh3)2] were synthesized and characterized using spectroscopic
techniques (IR, UV/visible, and 1D and 2D NMR), mass spectrometry,
elemental analysis, and X-ray diffraction. Interpretation of the in vitro cytotoxicity data of Cu(I) complexes took into
account their stability in cell culture medium. DFT calculations showed
that NMR properties, such as the shielding of carbon atoms, are affected
by relativistic effects, supported by the ZORA Hamiltonian in the
theoretical calculations. Additionally, the calculation of the energies
of the frontier molecular orbitals predicted that the structural changes
of the acylthiourea ligands did not cause marked changes in the reactivity
descriptors. All complexes were cytotoxic to the evaluated tumor cell
lines [MDA-MB-231 (triple-negative breast cancer, TNBC), MCF-7 (breast
cancer), and A549 (lung cancer)]. In the MDA-MB-231 cell line, complex 1 significantly altered the cytoskeleton of the cells, reducing
the density and promoting the condensation of F-actin filaments. In
addition, the compound caused an increase in the percentage of cells
in the fragmented DNA region (sub-G0) and induced cell death via the
apoptotic pathway starting at the IC50 concentration. Taken
together, the results show that complex 1 has cytotoxic
and apoptotic effects on TNBC cells, which is a cell line originating
from an aggressive, difficult-to-treat breast cancer.