Culture of Breast Cancer Cell Lines

Hec1A, AGS, and HCC1500 cells were acquired from ATCC. All other cell lines (HCC1806, SUM149, BT549, HCC1937, HCC70, BT20, MCF7, MDAMB453, EFM19, ZR75-1, and T47D) were acquired from the Brugge Lab at Harvard Medical School, and were authenticated by STR analysis. All cell lines were of female origin. Cell lines were regularly tested for mycoplasma using the MycoAlert Mycoplasma Detection Kit (Lonza). Cells were grown in human plasma-like medium according to the published formulation (Cantor et al., 2017 (link)) with 5% dialyzed FBS (Sigma) and Pen/Strep (Invitrogen) at 37 degrees C with 5% CO₂. Media was changed at least every two days. As needed, cells were incubated in RPMI media (R9010-01, US Biological Life Sciences) with or without serine and glycine with 5% dialyzed FBS and Pen/Strep. Cells were counted using a Z1 Coulter Particle Counter (Beckman Coulter) and growth rates were calculated using the following formula: growth rate = ln(final cell number/initial cell number)/time.