Dmem 4.5 g l d glucose

MCF7 and U2OS cells were cultured in DMEM
medium, supplemented with 10% fetal bovine serum, 1% sodium pyruvate,
and 1% nonessential amino acids at 37 °C. The MCF7 medium was
further supplemented with 10 μg/mL insulin. Generation of the
inducible Flp-In T-Rex 293 cell system expressing GFP, GFP-PRMT5,
GFP-RioK1, and GFP-pICln was carried out according to the manufacturer′s
instructions (Invitrogen, Thermo Fisher Scientific) and has been described
previously.^{29 (link),30 (link)} All Flp-In T-Rex 293 cells were
cultured in DMEM (4.5 g/L d-glucose; Gibco, Thermo Fisher
Scientific) supplemented with 10% (v/v) FCS (Biochrom, Merck), 100
U/mL penicillin, and 100 μg/mL streptomycin (Gibco, Thermo Fisher
Scientific) under a 5% CO₂ humidified atmosphere at 37
°C. For induction of GFP, GFP-PRMT5, GFP-RioK1, and GFP-pICln
expression, Flp-In T-Rex 293 cell lines were stimulated with 0.1 μg/mL
doxycycline (Clontech) for 18 h.

NSCLC cell lines were obtained from American Type Culture Collection (ATCC, LGC Standards, Wesel, Germany). A549 cells were cultured in high glucose F-12 K (Kaighn’s Modification of Ham’s F-12 Medium) mixture (GIBCO-BRL Co, NY, USA), supplemented with 10% fetal bovine serum (FBS) (GIBCO-BRL) and 1% penicillin/streptomycin (P/S) (GIBCO-BRL). The H1975 cell culture medium was D-MEM 4.5 g/L D-glucose (GIBCO-BRL) with 10% FBS/ 1% P/S. SKMES-1 cells were cultured in MEMα (GIBCO-BRL) medium supplemented with 10% FBS/1% P/S. Cells were maintained in a humidified atmosphere of 5% CO₂⁻ 95% air at 37 °C, and sub-cultivation was performed using ethylenediaminetetraacetic acid (EDTA)/Trypsin 0.25% (GIBCO-BRL).
Cytospins of H1975 cells and interferon gamma (IFN-γ)-treated A549 cells were also prepared to serve as controls for the optimization of the immunofluorescence stainings.

For cytotoxic analysis, the powder of the apatite samples was formed into round pellets (12 mm diameter and 1 mm thickness) using unixial pressing (130 mg/pellet) and the pellets were sterilized using gamma irradiation (BBF GmbH, Kernen-Rommelshausen, Germany). For the apatite pellets, 160 μL of an isotonic NaCl solution (0.9% NaCl) were added for 30 min. After that, the system was incubated for 24 h at 37 °C and 5% CO₂ with 500 μL cell culture media (DMEM, 4.5 g/L D-glucose, + L-glutamine, Gibco by Life Technologies). This was supplemented with 2 mM glutamine (Stock 200 mM), 100 U/mL penicillin + 100 μg/mL streptomycin (Stock: 10,000 U/mL Pen, 10,000 μg/mL Strep), 1% insulin, transferrin and selenium (Stock: 100x ITS-G), and 10% fetal calf serum. All the supplements were also provided by Gibco by Life Technologies.