A novel ruthenium complex with 5-fluorouracil suppresses colorectal cancer stem cells by inhibiting Akt/mTOR signaling

Valdenizia R Silva; Luciano de S Santos; Maria V L de Castro; Rosane B Dias; Ludmila de F Valverde; Clarissa A G Rocha; Milena B P Soares; Claudio A Quadros; Rodrigo S Correa; Alzir A Batista; Daniel P Bezerra

doi:10.1038/s41420-023-01759-6

A novel ruthenium complex with 5-fluorouracil suppresses colorectal cancer stem cells by inhibiting Akt/mTOR signaling

Cell Death Discov. 2023 Dec 16;9(1):460. doi: 10.1038/s41420-023-01759-6.

Authors

Affiliations

¹ Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Bahia, 40296-710, Brazil.
² Department of Propedeutics, School of Dentistry of the Federal University of Bahia, Salvador, Bahia, 40110-909, Brazil.
³ SENAI Institute of Innovation (ISI) in Health Advanced Systems, University Center SENAI/CIMATEC, Salvador, Bahia, 41650-010, Brazil.
⁴ São Rafael Hospital, Rede D'Or/São Luiz, Salvador, Bahia, 41253-190, Brazil.
⁵ Bahia State University, Salvador, Bahia, 41150-000, Brazil.
⁶ Department of Chemistry, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil.
⁷ Department of Chemistry, Federal University of São Carlos, São Carlos, São Paulo, 13561-901, Brazil.
⁸ Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Bahia, 40296-710, Brazil. daniel.bezerra@fiocruz.br.

Abstract

[Ru(5-FU)(PPh₃)₂(bipy)]PF₆ (Ru/5-FU) is a novel ruthenium complex with 5-fluorouracil with promising potential against colorectal cancer (CRC). In the present study, we investigated the molecular mechanism of Ru/5-FU action in HCT116 CRC cells. Ru/5-FU exhibited potent cytotoxicity on a panel of cancer cell lines and on primary cancer cells and induced apoptosis in HCT116 CRC cells. Ru/5-FU reduced AKT1 gene transcripts, as well as the expression of Akt1 and Akt (pS473) and downstream Akt proteins mTOR (pS2448), S6 (pS235/pS236), 4EBP1 (pT36/pT45), GSK-3β (pS9) and NF-κB p65 (pS529), but not Akt upstream proteins Hsp90 and PI3K p85/p55 (pT458/pT199), indicating an inhibitory action of Akt/mTOR signaling. Ru/5-FU increased LC3B expression and reduced p62/SQSTM1 levels, indicating autophagy induction. Curiously, the autophagy inhibitors 3-methyladenine and chloroquine increased Ru/5-FU-induced cell death, indicating an induction of cytoprotective autophagy by this compound. Ru/5-FU also reduced clonogenic survival, as well as the percentage of CD133+ cells and colonosphere formation, indicating that Ru/5-FU can suppress stem cells in HCT116 cells. Ru/5-FU inhibited cell migration and invasion in wound healing assays and Transwell cell invasion assays, along with a reduction in vimentin expression and an increase in E-cadherin levels, indicating that Ru/5-FU can interfere with epithelial-mesenchymal transition. Ru/5-FU also inhibited in vivo HCT116 cell development and experimental lung metastases in mouse xenograft models. Altogether, these results indicate that Ru/5-FU is an anti-CRC chemotherapy drug candidate with the ability to suppress stemness in CRC cells by inhibiting Akt/mTOR signaling.

Abstract

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