Figure 6. Albumin promotes spheroid viability in response to cystine deprivation.
(A) HT-1080N spheroids established over three days (day 0) prior to treatment for three days (Day 3). BSA: bovine serum albumin, 3% w/v. Scale bar = 100 µm. (B) Viability of HT-1080N spheroids as established and treated as in (A) determined using CellTiter-Glo. (C) mTOR pathway activity assessed by western blot following 24 h treatment. M: monolayer, S: spheroid. INK128: 1 µM. (D) Gliomaspheres (line: GS187) established over three days (day 0) prior to treatment for five days. BSA: 3% w/v. Scale bar = 100 µm. (E) Viability of GS187 spheroids as established and treated as in (D) determined using CellTiter-Glo. (F) mTOR pathway activity assessed by western blot in HT-1080N cells grown in monolayer (control) or GS187 cells grown as spheroids and treated ± INK128 (1 µM) for 24 h. In (A) and (D), images are representative of three independent experiments. In (B) and (E), data are mean ± SD from three independent experiments. In (C) and (F), blots are representative of three independent experiments. p-RPS6 is phosphorylated at Ser235/236. See also Figure S7.