Fig. 1
Gene expression profiling of 4T1 sublines from primary and metastatic sites. 4T1-Luc sublines independently isolated from primary tumours (T1–T3), lungs (L1–L3), or brains (B1–B4) were subject to gene expression profiling. a Unsupervised hierarchical clustering (Euclidean distance, average linkage) estimating the relation of the independent 4T1 sublines based on 17,550 probes. b Volcano plots showing differentially expressed genes (p < 0.001) between L vs. T, B vs. L, and B vs. T. X axes, gene expression shown on Log2(fold-change) scale; Y-axes, significance shown on –Log10(p value) scale. c Heat map (Pearson, ward.D2) of 186 genes (with official mouse gene symbol) differentially expressed between B and T, between B and L, or between L and T sublines with an absolute fold change ≥ 2.0, p < 0.001. Sublines are in the same order as in Fig. 1a. Arrowheads indicate Id2 and Aldh3a1. See Additional file 1 (Figure S1) for a higher power image including gene names. d RT-qPCR analysis of Id2 and Aldh3a1 expression in sublines used in a, plus five or six independently isolated brain metastasis sublines. e,f Immunoblotting of (e) sublines used in a or (f) independently isolated 4T1-Luc T, L, and B sublines. Molecular size makers are in kDa. Arrows indicates the lower migrating Aldh3a1 protein. g 4T1-Luc-RFP cells were isolated from primary tumours, lungs, and brains of BALB/c mice inoculated subcutaneously, intravenously, or intracranially, respectively. Expression of Id2 and Aldh3a1 was analysed by RT-qPCR, n = 5 mice per group. Mean ± SEM. **p < 0.01, ***p < 0.001, one-way ANOVA. ns not significant