Figure 1.

Quiescent cancer cells are resistant to chemotherapy. Experimental setup: FUCCI-expressing MKN45 cells (5×10⁶ cells/mouse) were injected subcutaneously into the left flanks of nude mice. When the tumors reached approximately 6 mm in diameter (tumor volume, 80–100 mm³), mice were intraperitoneally injected with cisplatinum (CDDP) (4 mg/kg), paclitaxel (PTX) (5 mg/kg) or doxorubicin (DOX) (6 mg/kg) for 3 cycles every 3 d. Representative images of cross-sections of FUCCI-expressing MKN45 subcutaneous tumor of control (A), treated with CDDP (B), PTX (C), or DOX (D) 7 d and 21 d after last treatments. Low-magnification image (left). High-magnification image (right). Superficial area image (upper right), deep area image (lower right of the upper and lower subpanels, respectively, in each panel). The cells in G₀/G₁, S, or G₂/M phases appear red, yellow, or green, respectively. (E, F) Histograms show cell-cycle phase of FUCCI-expressing MKN45 subcutaneous tumors of control (A); treated with CDDP (B); PTX (C); or DOX (D). Data are shown as means ± SD (n = 5). Scale bars, 500 μm.

Figure 1.

(Continued)