Nicotinamide

The human GPR44-expressing Chinese hamster ovarian (CHO-K1) stable cell line was purchased from PerkinElmer and was cultured, according to the provider’s recommendations, in Ham’s F-12 (Gibco) supplemented with 10% FBS (Gibco), 0.4 mg/mL G418 (Corning), 1% Penicillin/Streptomycin (PEST) (Gibco) and 2 nM L-Glutamine (Gibco). Non-transfected CHO-K1 cells used as negative control were purchased from ATCC and cultured in Ham’s F-12 (Gibco) supplemented with 10% FBS (Gibco) and 1% PEST (Gibco).
The human beta-cell line EndoC-BH1 was obtained from Endocells and cultured according to the provider’s indications in DMEM low glucose supplemented with 2% Bovine Serum Albumin (BSA) (Roche Diagnostics), 50 µM 2-mercaptoethanol (Sigma-Aldrich), 10 mM nicotinamide (VWR Life Science), 5.5 µg/mL transferrin and 6.7 ng/mL sodium selenite.

INS1(832/13) pancreatic β cells⁶⁰ (link) were cultured in RPMI medium (11 mM glucose) supplemented with 10% (v/v) fetal calf serum, 20 mM HEPES, 50 μM beta-mercaptoethanol plus penicillin (100 units/mL) and streptomycin (0.1 mg/mL) at 37°C in an atmosphere of humidified air (95%) and CO₂ (5%). EndoC-βH1 cells were kindly provided by Dr. Philippe Ravassard (CRICM CNRS UMR 7225, Paris, France) and grown in serum-free DMEM (Life Technology) containing low glucose (1 g/L), 2% (w/v) albumin from bovine serum fraction V (Roche Diagnostics), 50 μM β-mercaptoethanol, 10 mM nicotinamide (VWR), 5.5 μg/mL transferrin (Sigma-Aldrich), 6.7 ng/mL sodium selenite (Sigma-Aldrich), penicillin (100 units/mL), and streptomycin (100 μg/mL).