Fig. 6

Id2 expression protects against apoptosis. a 5 × 10⁴ 4T1-Luc cells expressing vector alone (Vec) or with ectopic expression of Id2 were cultured in six-well low-adherence plates in 2% FBS for 24 h before annexin V/PI staining. Data shown as percent of healthy cells (annexin V^–, PI^–) remaining, n = 3. Mean ± SEM. **p < 0.01, Student’s t test. b Parental 4T1-Luc cells cultured in suspension as described in a in the presence of absence of bone morphogenetic protein (BMP)7 (300 ng/mL) for 24 h prior to annexin V/PI staining. Data shown as percent of healthy cells (annexin V^–, PI^–) remaining, three samples per condition. Mean ± SEM. **p < 0.01, Student’s t test. c 750 parental 4T1-Luc cells (4T1) or 4T1-Luc cells transduced with empty vector (Vec) or with ectopic expression of Id2, or 4T1-Luc cells transduced with non-targeting control short hairpin RNA (shNTC) or shRNA targeting Id2 (shId2) were sorted into low-adherence 96-well U-bottomed plates in DMEM plus 2% FBS and cultured in the presence or absence of BMP7 (300 ng/mL) for 7 days before viability was monitored by CellTiter-Glo. Data from n = 5 wells/sample. *p < 0.05, **p < 0.01, ***p < 0.001, two-way ANOVA with Tukey’s post-test. ns not significant