Extended Data Figure 7: Overexpression of Serpine2 and Slpi in parental 4T1 and clonal cell lines.

a, Images of HUVECs, parental 4T1, 4T1-L, 4T1-I, 4T1-E and 4T1-T cells grown on Matrigel to assess tube formation ability. b, Number of tubular structures identified per ×5 microscopic field when 4T1-T cells had been infected with a non-targeting shRNA or shRNAs targeting Serpine2 or Slpi and grown on Matrigel (P < 0.0002, Wilcoxon rank-sum, n = 8 fields). c, Number of tubular structures identified per ×5 microscopic image when non-intravasating 4T1 clonal lines had been infected with an empty retroviral vector or vectors for overexpression of Serpine2 or Slpi (P < 0.03, Wilcoxon rank-sum, with the exception of 4T1-B overexpressing Slpi, n = 4 fields). d, Relative CTC proportions of the cells described in c after they had been pooled with the remaining clonal lines and orthotopically injected (P < 0.05, Wilcoxon rank-sum, with the exception of 4T1-F and 4T1-B Slpi, n = 10 mice). e, PAS⁺/CD31⁻ channels in primary tumours resulting from orthotopic injection of parental 4T1 cells infected with an empty retroviral vector or vectors for overexpression of Serpine2 or Slpi (P < 0.01, Wilcoxon rank-sum, n = 10 fields). f, Quantification of the number of lung metastatic nodules resulting from the tumours described in e after 18 days (n = 4 mice). g, Quantification of the number of lung metastatic nodules resulting from the tumours described in e after 24 days (P < 0.05, Friedman, n = 10 mice). For all box plots, the edges of the box are the twenty-fifth and seventy-fifth percentiles. The error bars extend to the values q3 + w(q3 − q1), and q1 − w(q3 − q1), in which w is 1.5 and q1 and q3 are the twenty-fifth and seventy-fifth percentiles.