title: Deep Proteomics of Breast Cancer Cells Reveals that Metformin Rewires Signaling Networks Away from a Pro-growth State.
abstract: Metformin is the most frequently prescribed drug for type 2 diabetes. In addition to its hypoglycemic effects, metformin also lowers cancer incidence. This anti-cancer activity is incompletely understood. Here, we profiled the metformin-dependent changes in the proteome and phosphoproteome of breast cancer cells using high-resolution mass spectrometry. In total, we quantified changes of 7,875 proteins and 15,813 phosphosites after metformin changes. To interpret these datasets, we developed a generally applicable strategy that overlays metformin-dependent changes in the proteome and phosphoproteome onto a literature-derived network. This approach suggested that metformin treatment makes cancer cells more sensitive to apoptotic stimuli and less sensitive to pro-growth stimuli. These hypotheses were tested in vivo; as a proof-of-principle, we demonstrated that metformin inhibits the p70S6K-rpS6 axis in a PP2A-phosphatase dependent manner. In conclusion, analysis of deep proteomics reveals both detailed and global mechanisms that contribute to the anti-cancer activity of metformin.
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy; Department Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany.
authors.forename: Francesca
authors.initials: F
authors.lastname: Sacco
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Silvestri
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Posca
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pirrò
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
authors.forename: Pier Federico
authors.initials: PF
authors.lastname: Gherardini
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Castagnoli
authors.affiliation: Department Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany. Electronic address: mmann@biochem.mpg.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Mann
authors.affiliation: Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy; Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, Italy. Electronic address: cesareni@uniroma2.it.
authors.forename: Gianni
authors.initials: G
authors.lastname: Cesareni
mesh_terms: D001943:Breast Neoplasms; D003924:Diabetes Mellitus, Type 2; D006801:Humans; D007004:Hypoglycemic Agents; D008687:Metformin; D040901:Proteomics
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin