Figure 2. G-1 arrests cell cycle progression of breast cancer cells in the prophase of mitosis.

A) Representative images showing morphology of MDA-MB-231 cells incubated for 8 h in the absence (CTRL) or presence of G-1 (2 μM) for 8 h. Microtubules were stained with β-tubulin antibody (red) and the nuclei were stained with DAPI (blue). Phosphorylated histone H3 (S10) was used as cell cycle progression marker (green). Cells in different stages of cell cycle were indicated by white arrows. Scale bar: 20 μm. B) Representative high-resolution confocal microscopy images showing detailed morphology of microtubules of MDA-MB-231 breast cancer cells incubated in the absence (top panel) or presence (lower panel) of G-1 (2 μM) for 8 h. Scale bar: 20 μm. Microtubules were stained with β-tubulin antibody (red) and the nuclei were stained with DAPI (blue). Phosphorylated histone H3 (S10) was used as cell cycle progression marker (green). I: interphase; P: prophase; M: metaphase; A: anaphase; T&C: telophase and cytokinesis. C) A representative high-resolution image showing the microtubule asters formed in MDA-MB-231 cells after G-1 treatment for 8 h. Microtubules were stained with β-tubulin antibody (red) and the nuclei were stained with DAPI (blue). Phosphorylated histone H3 (S10) was used as cell cycle progression marker (green). White arrowheads point to spindle-like microtubule asters. Scale bar: 20 μm.