L glutamine solution

The HNSCC cells line, CAL27, derived from squamous carcinoma of the oral tongue, was kindly gifted by the laboratory of Experimental Radiotherapy, Leuven, Belgium. The cells were propagated in culture in Dulbecco’s Modified Eagle Medium (DMEM) high glucose, supplemented with 10% heat-inactivated fetal bovine serum, 1% L-glutamine solution 200 mM, and 1% penicillin/streptomycin solution 100 U mL⁻¹ (all supplied by Euroclone, Pero, Italy). The cells were cultured in incubator at 37 °C in a 5% CO₂ humidified atmosphere. To maintain exponential growth, the cells were trypsinized using the cell dissociation solution, Versene (Merck, Darmstadt, Germany), before reaching 80% confluence.

Porcine jejunal epithelial cells (IPEC-J2, IZSLER Cell Bank code BS CL 205) were grown in a mixture (1:1) of Dulbecco’s Modified Eagle (DMEM) (Euroclone, Milan, Italy) and Nutrient Mixture F-12 (F12) (Euroclone, Milan, Italy) enriched with 10% Fetal Bovine Serum (FBS, GIBCO^TM, Thermofisher Scientific, Milan, Italy), 1% L-glutamine solution (Euroclone, Milan, Italy) and 1% penicillin/streptomycin solution (Euroclone, Milan, Italy) and kept in culture at 37 °C under 5% CO_2.

HNSCC cells lines CAL27, derived from squamous carcinoma of the oral tongue, and SQD9, from laryngeal squamous carcinoma, were kindly gifted by the laboratory of Experimental Radiotherapy, Leuven, Belgium. Cells were propagated in culture in DMEM high glucose cell medium, supplemented with 10% heat-inactivated fetal bovine serum, 1% L-glutamine solution 200 mM, and 1% penicillin/streptomycin solution 100 U mL⁻¹ (all provided by Euroclone, Pero, Italy). Cells were cultured at 37 °C in a 5% CO₂ humidified incubator. To maintain exponential growth, cells were trypsinized before reaching 80% confluence using the cells dissociation solution Versene (Merck, Sigma-Aldrich, Darmstadt, Germany).