Novel versatile europium and terbium complexes as bioprobes and anticancer agents

abstract

Focusing on the pertinent research on dual activity (as probes and cancer inhibitors), two novel Eu and Tb lanthanide complexes were prepared in this work alongside their binuclear counterparts holding Cu as the secondary metal. Complexes that did not contain copper were found to be less effective in promoting cancer cell death, in contrast to their bimetallic counterparts, which could function as inhibiting molecules while sequestering Cu from the tumoral environment. The ANOVA test results showed that, for A549 cells, the Eu complexes didn't present relevant differences, whereas the results for their Tb counterparts were confirmed as being different. All complexes were structurally characterized by using high-resolution mass spectrometry, vibrational, electronic and fluorescence spectroscopy. TD-DFT calculations were carried out to assess the nature of the electronic transitions and ANOVA test to evaluate whether each pair of complexes was similar concerning their activity on the cell lines (null hypothesis). Data showed that the mononuclear Eu and Tb complexes had, as expected, fluorescent properties while their binuclear counterparts (holding Cu) did not. The mononuclear complexes were titrated with Cu2+ confirming their ability to sequester the latter in a tumor microenvironment. All synthesized compounds were pH responsive, although they maintained their structures in the physiological pH range and were investigated in cell viability tests with HeLa (breast) and A549 (lung adenocarcinoma) cancer cell lines towards assessing how they induce cell death. Overall, this work showed that these complexes could play an important role as bioprobes as well as anticancer agents.

keywords

LUMINESCENT LANTHANIDE COMPLEXES; AB-INITIO PSEUDOPOTENTIALS; BETA-DIKETONATE COMPLEX; EU-III COMPLEXES; PROTEASOME INHIBITORS; NONCONJUGATED COPOLYMERS; EXCITATION-ENERGIES; APOPTOSIS INDUCERS; MCM-41; APPROXIMATION

subject category

Chemistry

authors

Felicio, MR; Vaz, PD; Nunes, CD; Nolasco, MM

Groups

G6 - Virtual Materials and Artificial Intelligence

Projects

Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was supported by FundacAo para a Ciencia e Tecnologia - Ministerio da Ciencia e Tecnologia e Ensino Superior (FCT-MCTES, Portugal), projects PTDC/CTN-NAN/112168/2009, LA/P/0056/2020 and UIDB/00100/2020, UIDP/00100/2020. CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). This research is also sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade-and by national funds through the FCT under the project UID/EMS/00285/2020. MRF acknowledges FCT-MCTES for a fellowship BI/UI89/6092/2012. Computing resources provided by STFC Scientific Computing Department's SCARF cluster are also acknowledged.