Fig. 4.

Reduction of integrin β3 enhances IGFBP-4 and reduces tumor growth and angiogenesis in vivo. Expression of β3 integrin was reduced in M21 cells by transfection with a β3-specific shRNA. a Western blot analysis of β3 protein in M21Cont and M21β3-KD cells. b Quantification of IGFBP-4 mRNA in M21Cont and M21β3-KD cells by real-time RT-PCR. c M21 tumor cell variants were injected in nude mice and allowed to grow for 17 days. Top panel Quantification of growth of M21Cont and M21β3-KD cells in nude mice. Data bars represent mean tumor volumes ± SE from 10 mice per condition. Bottom panel Example of tumor tissues from each tumor variant stained by H&E. Experiments were repeated twice with similar results. d. Quantification of the mean tumor vessels from each tumor variant. Data bars represent mean vessel counts ± SE per ×100 microscope fields (n = 5) for each of three independent tumors from each condition. e Total vascular volume was quantified from M21 tumor variants using lCT scanning of tumors injected with microfil. Top panels example of vascular networks from each tumor type. Bottom panel quantification of mean vascular volume ± SE from entire three-dimensional tumor mass from six tumors from each variant corrected for tumor size. *Indicates P values <0.05