Breast cancer cell line MCF7 escapes from G1/S arrest induced by proteasome inhibition through a GSK-3β dependent mechanism.
Targeting the ubiquitin proteasome pathway has emerged as a rational approach in the treatment of human cancers. Autophagy has been described as a cytoprotective mechanism to increase tumor cell survival under stress conditions. Here, we have focused on the role of proteasome inhibition in cell cycle progression and the role of autophagy in the proliferation recovery. The study was performed in the breast cancer cell line MCF7 compared to the normal mammary cell line MCF10A. We found that the proteasome inhibitor MG132 induced G1/S arrest in MCF10A, but G2/M arrest in MCF7 cells. The effect of MG132 on MCF7 was reproduced on MCF10A cells in the presence of the glycogen synthase kinase 3β (GSK-3β) inhibitor VII. Similarly, MCF7 cells overexpressing constitutively active GSK-3β behaved like MCF10A cells. On the other hand, MCF10A cells remained arrested after MG132 removal while MCF7 recovered the proliferative capacity. Importantly, this recovery was abolished in the presence of the autophagy inhibitor 3-methyladenine (3-MA). Thus, our results support the relevance of GSK-3β and autophagy as two targets for controlling cell cycle progression and proliferative capacity in MCF7, highlighting the co-treatment of breast cancer cells with 3-MA to synergize the effect of the proteasome inhibition.
1] Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocío, Universidad de Sevilla, Sevilla, Spain [2] Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.
Elena
E
Gavilán
Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, Sevilla, Spain.
Servando
S
Giráldez
Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, Sevilla, Spain.
Inmaculada
I
Sánchez-Aguayo
Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, Sevilla, Spain.
Francisco
F
Romero
1] Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocío, Universidad de Sevilla, Sevilla, Spain [2] Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.
Diego
D
Ruano
Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes 6, Sevilla, Spain.
Paula
P
Daza
D001343:Autophagy; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D049109:Cell Proliferation; D059585:G1 Phase Cell Cycle Checkpoints; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D061986:MCF-7 Cells; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D059807:S Phase Cell Cycle Checkpoints; D015398:Signal Transduction
C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D046988:Proteasome Endopeptidase Complex