Proinvasive and 'bone metastasis signature' gene expression patterns in cell lines with variable CD44+/CD24- subpopulation. (a) A representative Northern analysis of bone metastasis signature genes and proinvasive genes is shown. CD44+/CD24- status and ER-α expression pattern in cell lines are indicated. RT-PCR results of IL-8 and the control 36B4 are shown on the right. (b) CD44 and CD24 expression patterns in CD44+/CD24- and CD44+/CD24+ subpopulations of TMD-436 sorted by flow cytometry. Expression in pre-sorted and post-sorted cells is shown. (c) Expression of IL-8, IL-6, MMP-1, and UPA in CD44+/CD24- and CD44+/CD24+ subpopulations of TMD-436 cells, as determined by Northern blot analysis. ER, estrogen receptor; MMP, matrix metalloproteinase; UPA, urokinase plasminogen activator.