Figure 2.

Mouse lung cancer cells exposed to intermittent hypoxia (IH) had greater stem cell potential and stronger proliferation and differentiation ability. (A) Lung cancer cell lines (PC-9, A549) were exposed to IH. (i) Colony formation of lung cancer cell lines. CSCs measured at 0 h, 24 h, and 48 h after exposure to IH. (ii) Immunohistochemistry of CSCs (PC-9, A549). (iii) Immunofluorescence staining of CSCs (PC-9, A549) (75). (B) Lung carcinoma cell lines (A549, SPCA1) were exposed to IH. (i) After exposure of A549 or SPCA1 to normal oxygen (Nor) or chronic intermittent hypoxia (CIH) for 48 h, cell proliferation was assessed with EDU and DAPI staining. (ii) Colony formation analysis shows that IH could promote the proliferation of CSCs (A549, SPCA1). (iii) Comparison of EDU staining positive ratio in CSCs (A549, SPCA1) between Nor and CIH (left) and comparison of CSC (A549, SPCA1) colonies between Nor and CIH (right) (76). Reprinted with permission from Ref (75, 76).