Figure 4: Myc regulates metastasis by enhancing tumor cell intravasation.
A. Bar graph showing Myc mRNA levels in cell lines derived from MetHigh and MetLow tumors, normalized to Gapdh (n=6 MetHigh and n=5 MetLow cell lines).
B. Western blot showing corresponding MYC protein levels in cell lines derived from MetHigh and MetLow tumors shown in (A).
C. Representative fluorescent images of primary tumors and associated liver and lung metastases following orthotopic transplantation of the cell lines in (A) and (B) into NOD.SCID mice. The bar graph shows the total number of metastases (liver and lung) counted following orthotopic transplantation of 5 MetLow cell lines or 5 MetHigh cell lines (pooled data from n=49 mice in total).
D. Representative fluorescent images of primary tumors, liver, and lung metastases following orthotopic transplantation of MetLow cell lines that were stably transduced with either a Myc overexpression construct (Myc_OE) or empty vector (EV). The bar graph shows the total number of metastases (liver and lung) counted following orthotopic transplantations of Myc_OE or EV cells. Data were pooled from 4 independent MetLow lines transduced with either the Myc_OE or EV construct transplanted into 12 NOD.SCID (for the Myc_OE cells) or 10 NOD.SCID mice (for the EV cells).
E. Quantification of circulating tumor cells (CTCs) in arterial blood derived from the orthotopic tumors depicted in (c) (n=27 mice examined) and (D) (n=12 mice examined).
F. Representative fluorescent images of lung metastases following tail vein injection of cell lines derived from the MetLow and MetHigh primary tumor clones. The bar graph shows the total number of lung metastases counted following tail vein injection of 5 MetLow cell lines or 5 MetHigh cell lines (pooled data from n=36 mice in total).
Statistical analysis by Student’s unpaired t-test with significance indicated (*, p=0.0152; **, p = 0.013; ***, p= 0.0008; **** p < 0.0001; ns, not significant). Error bars indicate SEM (C-F). Scale bar = 1 mm (C-D,F).