Hcc1806

4T1, E0771, HCC1806, and RAW 264.7 cells were purchased from the American Type Culture Collection (ATCC, USA; CRL-2539 for 4T1, CRL-3461 for E0771, CRL-2335 for HCC1806, TIB-71 for RAW 264.7). HCC 1806 and 4T1 cells were cultured in RPMI 1640 medium with 10% FBS, 1% penicillin and 1% streptomycin (Invitrogen). E0771 and RAW 264.7 cells were cultured in DMEM medium with 10% FBS, 1% penicillin, 1% streptomycin, and 20 mM HEPES. Cell passage was done every 3–5 days. The cells were cultured at 37 °C in a humidified incubator with 5% CO₂.

The human triple negative breast cancer cell lines MDA-MB-231 (Cellosaurus: CVCL_0062) and HCC-1806 (CVCL_1258) were obtained from ATCC (Manassas, VA, USA). SUM-159 (CVCL_5423) cells were a kind gift from Andreas Trumpp (DKFZ, Heidelberg, Germany). All cell lines were authenticated using Multiplex Cell Authentication by Multiplexion (Heidelberg, Germany) as previously described [14 (link)]. The SNP profiles matched the expected ones. All cell lines were routinely tested for potential contamination with mycoplasma. MDA-MB-231 cells were cultured in Leibovitz-L15 medium (Gibco, Thermo Fisher Scientific) supplemented with 10% fetal calf serum (Gibco) and 3 g/l of sodium bicarbonate. HCC-1806 cells were cultured in RPMI-1640 (Gibco), supplemented with 10% fetal calf serum (Gibco). SUM-159 cells were cultured in Ham’s F12 (Gibco), supplemented with 5% fetal calf serum (Gibco), 10 mM Hepes (Gibco), 10 μg/ml Hydrocortisone (Sigma, Merck KGaA, Germany), and 5 μg/ml human recombinant Insulin (Sigma). All cell lines were cultured in incubators maintained at 37 °C and 5% CO₂.

The established human breast cancer cell lines MCF7, BT-474, HCC1806, HCC1937 (ATCC, Manassas, VA), SUM-229PE (Asterand, San Francisco, CA), and a primary cell culture generated from invasive ductal breast carcinoma (IDC) [19 (link)], were maintained under standard cell culture conditions. For experiments, cells were incubated in the presence of different calcitriol concentrations (0.1–1000 nM, Sigma-Aldrich, St Louis, MO) or its vehicle (0.1 % ethanol) during 24 h. Afterwards, cells were used for RNA isolation. Characterization of the cells was performed by immunocytochemistry in order to analyze the expression of particular molecular markers.

Breast cancer cell lines [MCF-7 (RRID:CVCL_0031), SK-BR-3 (RRID:CVCL_0033), HCC1806 (RRID:CVCL_1258), MDA-MB-468 (RRID:CVCL_0419)] were obtained from ATCC in 2011. Cell lines have not been authenticated since purchase from the manufacturer. Mycoplasma testing was performed PCR in October of 2019 prior to freeze-back. Cell lines were passaged for at least one month prior to the experiments described here. All cell lines were cultured in DMEM (Hyclone) with 10% FBS (Invitrogen), 2 mmol/L glutamine (Hyclone), 0.1 mmol/L nonessential amino acids (Hyclone), 1 mmol/L sodium pyruvate (Hyclone), and 2 μg/mL gentamicin (Invitrogen). 8-chloroadenosine and 8-azaadenosine were purchased from Tocis (catalog numbers: 4436 and 6868).

All cell lines used in this study, including HCC1806, HCC1937, and HEK293T cells, were purchased from ATCC (American Type Culture Collection, Manassas, VA, USA) and validated by STR (short tandem repeat) analysis and these cell lines tested negative for mycoplasma contamination. HCC1806 and HCC1937 cells were cultured in RPMI 1640 medium supplemented with 5% fetal bovine serum (FBS). HEK293T cells were cultured in DMEM (Thermo Fisher, Grand Island, USA) with 5% FBS at 37°C with 5% CO₂. Epirubicin (EPI) (Cat#HY-13624A), cisplatin (DDP) (Cat#HY-17394), talazoparib (BMN) (Cat#HY-16106), and olaparib (AZD) (Cat#HY-10162) were purchased from MCE (New Jersey, USA).

TNBC cell line CAL-51 was grown in DMEM (Gibco) supplemented with 20% fetal bovine serum (FBS, Serana), 1% penicillin-streptomycin (P/S, Gibco) and 2mM L-glutamine (Gibco). TNBC cell line CAL-120 was grown in DMEM supplemented with 10% FBS, 1% P/S and 2 mM L-glutamine. TNBC cell line HCC1806, lung cancer cell lines A549 and H2122, colon cancer cell lines DLD-1 and RKO were grown in RPMI (Gibco) supplemented with 10% FBS, 1% P/S and 2 mM L-glutamine. TNBC cell line SUM159 was grown in DMEM/F12 (Gibco) supplemented with 10% FBS, 1% P/S, 5 μg/ml insulin (Sigma-Aldrich) and 1μg/ml hydrocortisone (Sigma-Aldrich).
HCC1806, A549, RKO, H2122 and DLD-1 were purchased from ATCC. SUM159 was a gift from Metello Innocenti (NKI, Amsterdam). CAL-51 and CAL-120 were obtained from DSMZ. All cell lines were regularly tested for mycoplasma contamination using a PCR assay and STR profiled (Eurofins).