L quisqualate

Riluzole (#0768), L-quisqualate (#0188), Sulfasalazine (#4935), S-4-carboxy-phenylglycine (S-4-CPG) (#0322) were purchased from Tocris Bioscience (Minneapolis, MN, USA). G418 (#11811031) was purchased from Gibco (Invitrogen, Carlsbad, CA, USA). Anti-xCT antibody (1:1000, #PA1–16893) antibody was purchased from Pierce Biotechnology (Rockford, IL, USA). Anti-Flag tag antibody was purchased from Origene (1:1000, #TA100011). Anti-GAPDH (1:1000, #5174) and anti-β-actin (1:1000, #4970) antibodies were obtained from Cell Signaling Technology (Danvers, MA, USA).

The MCF10A series of cell lines were originally developed at the Michigan Cancer Foundation (the institutional precursor to the Karmanos Cancer Institute) and are available to us from original stocks at low passage [28] (link), [31] (link)–[33] (link). MCF10A series cell lines were cultured in DMEM/F12 (1∶1) media (Life Technologies, Carlsbad, CA) supplemented with 5% horse serum, 10 µg/ml insulin, 20 µg/ml EGF, 0.5 µg/ml hydrocortisone and 100 ng/ml cholera toxin plus antibiotics at 37°C, 5% CO₂. MCF10A and MCF10AT1 transduced with pLenti-GRM1 or control LacZ were grown with 5 to 8 µg/ml blasticidin (Life Technologies, Carlsbad, CA); MCF10DCIS.com and MCF10CA1d transduced with lentiviral GIPZ shGRM1 or non-silencing control were maintained in 2 µg/ml puromycin (Life Technologies, Carlsbad, CA). The noncompetitive mGluR1 inhibitor BAY36-7620 [(3aS,6aS)-6a-naphtalen-2-ylmethyl-5-methyliden-hexahydro-cyclopental [c]-furan-1-on], competitive mGluR1 inhibitor LY367385 [(S)-(+)-α-Amino-4-carboxy-2-methylbenzeneacetic acid], and mGluR1 agonist L-quisqualate [(L)-(+)-a-amino-3,5-dioxo-1,2,4-oxadiazolidine-2-propanoic acid] were purchased from Tocris Bioscience (Ellisville, MO, USA).