Figure 3.

Constituative Notch3 activity is anti-proliferative and induces expression of quiescence-associated genes. (A) Overexpression of Notch3 intracellular domain (N3^ICD) by adenoviral infection of HC11 cells. β-actin as loading control. (B) overexpression of N3^ICD activates Notch signaling. Relative luciferase activity from CBF-luc reporter following GFP or N3^ICD overexpression. (C) N3^ICD suppresses HC11 proliferation similar to ΔNp63α. HC11 cells were trypsinized and counted every 12 h following plating and infection with adenoviral N3^ICD or GFP. (D and E) N3^ICD induces mRNA of canonical Notch signaling targets and quiescence-mediating genes. Overexpression of N3^ICD increases mRNA of the canonical Notch signaling target and regulator of quiescence, Hes1 (C) and the c-myc-regulating mediator of quiescence, Mxi1 (D) as assessed by qPCR (p < 0.05).