Figure 7. FAVL elevation initiates growth advantages.

(A) Overexpression of FAVL promotes cell proliferation rate. A growth curve made from average cell number ± SEM, with n = 3, is shown. Cells overexpressing FAVL have a faster growth rate (pink line) than control cells (black line). Elevated FAVL leads to colony formation in soft agar. There was not a single colony (>50 cells) that could be scored from dishes plated with U2OS control cells carrying empty vector. Ten fields per one culture dish were viewed under a light microscope, at an original magnification of ×40. A pair of typical views was shown. (B) U2OS cells overexpressing FAVL form xenograft tumors in nude mice. The left side of the mouse was injected with U2OS cells, which had been pool selected and overexpressed FAVL, and the right side of the same mouse was injected with control U2OS cells, containing empty vector that had been subjected to the same selection process. One of four mice in the group is shown here, and the other mice and growth curves of xenograft tumors are shown in Supplemental Figure 7A. (C) U2OS xenograft tumors expressing high levels of FAVL are high-grade, poorly differentiated osteosarcomas. H&E images show a high number of mitotic figures (red arrows) and large areas of coagulative tumor cell necrosis (marked with yellow lines) and nuclear polymorphism. Morphologic differentiation is shown in Supplemental Figure 7C. Original magnification, ×400.