Automated approach for the evaluation of glutathione-S-transferase P1-1 inhibition by organometallic anticancer compounds

Abstract

A novel automated method based on sequential injection analysis (SIA), a non-segmented flow injection technique, was developed to evaluate glutathione S-transferase P1-1 (GST P1-1) activity in the presence of organometallic complexes with putative anticancer activity. The assay is based on the reaction of L-glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB) in the presence of GST P1-1 to afford the GS-DNB conjugate and the reaction may be monitored by an increase in absorbance at 340 nm. A series of ruthenium, iron, osmium and iridium complexes were evaluated as GST P1-1 inhibitors by evaluating their half-maximal inhibitory concentration (IC₅₀). An iridium compound displays the lowest IC₅₀ value of 6.7 ± 0.7 µM and an iron compound displays the highest IC₅₀ value of 275 ± 9 µM. The SIA method is simple to use, robust, reliable, and efficient and uses fewer reagents than batch methods and each analysis takes only 5 minutes.

Graphical Abstract

Keywords:

• Sequential injection analysis (SIA)
• glutathione S-transferase P1-1
• enzyme inhibition assays
• anticancer metal complexes

Acknowledgments

This work received support and help from UIDB/50006/2020 and UIDP/50006/2020with funding from FCT/MCT ES through national funds. Sarah A. P. Pereira acknowledged FCT for her Ph.D. Grant (SFRH/BD/138835/2018).

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This work received financial support from the project with reference PTDC/QUIQAN/ 30163/2017 - Tailored NanoGumbos: The green key to wound infections chemosensing, supported by national funds by FCT/MCTES and co-supported by Fundo Europeu de Desenvolvimento Regional (FEDER) through the Operational Competitiveness Program (COMPETE)–reference number P OCI-01-0145-FEDER-030163.