Figure 2.

Tamoxifen-induced deletion of Mekk3 in Mekk3^flox/− Cre-ER mice results in decreased vessel formation and tumor growth in vivo. BM cells and heart (A) were obtained from Mekk3^flox/+ Cre-ER and Mekk3^flox/− Cre-ER mice 2 wk after tamoxifen administration. The resulting Mekk3^Δflox/+ and Mekk3^Δflox/− cells were assessed for Mekk3 expression by Western blot. B, following tamoxifen treatment, mice were injected with Matrigel. The Matrigel plugs were excised 2 wk later and assessed by immunohistochemistry using CD31. The average number of CD31⁺ vessels was calculated by counting five random high-power microscopic fields from different Matrigel plug sections. C, 3LL cells were injected into the Mekk3^Δflox/+ and Mekk3^Δflox/− mice 2 wk after tamoxifen administration. Tumor growth was assessed 3 wk after tumor cell injection. Error bars represent SD.