Fig. 2
From: Hypoxia-reprogrammed tricarboxylic acid cycle promotes the growth of human breast tumorigenic cells
Hypoxia promotes the growth of human breast cancer TRCs. a ALDH1high and ALDH1low tumor cells were sorted from breast tumor tissue by Aldefluor assay and then were seeded (400 cells per group) into 90 Pa soft 3D fibrin gels in 1% O2 culture incubator. The colony number was calculated. b, c 1.25 × 103 MCF-7 (b), BT474 or MDA-MB-468 (c) cells were seeded into 90 Pa soft 3D fibrin gels under 21% O2 (normoxia) or 1% O2 (hypoxia) for 6 days, then the colony size was calculated. d, e Primary tumor cells isolated from three human breast cancer samples were seeded into 90 Pa soft 3D fibrin gels in normoxia or hypoxia for 6 days, the colony size of TRCs was analyzed. f 8 × 103 MCF-7 cells were seeded into 90 Pa soft 3D fibrin gels for 5 days under normoxic or hypoxic conditions, cells were collected and the cell cycle was analyzed by BrdU and 7AAD staining as described in methods. g MCF-7 cells (2 × 104) were cultured in rigid dish under normoxic or hypoxic conditions, the cell number was counted each day. h MCF-7 TRCs were cultured under normoxic or hypoxic condition for 5 days and apoptosis was analyzed by annexin V and PI staining. i Aldh1a1, Sox2, Oct3/4, Klf4, and CD133 mRNA levels in normoxic and hypoxic MCF-7 TRCs were analyzed by real-time PCR. j Hypoxic or normoxic MCF-7 TRCs were subcutaneously inoculated into NOD-SCID mice with different cell counts, and tumor incidence was analyzed. Data shown are representative of three independent experiments and error bars represent mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. NS, no significance. Scale bar, 20 μm
