Figure 5.
Decreased TGF-β responsiveness does not affect primary tumorigenesis but suppresses metastasis in the high-grade breast carcinoma line M-IV. (a) Tumor growth kinetics in vivo. Nude mice were inoculated subcutaneously on each hind flank with retrovirally transduced M-IV cells (2 × 105 cells/site). For M-IV CON, n = 11 sites injected; M-IV DNR, n = 11. Untransduced parental M-IV cells gave essential identical results to M-IV CON (n = 4, not shown). (b) Lung metastases. Metastatic efficiency was determined by quantitation of histologically detectable lung metastases 8 weeks after injection of 106 retrovirally transduced cells into the tail vein of nude mice. Results are the mean ± SD for n = 5 (M-IV CON) and n = 10 (M-IV DNR). CON, cells transduced with pLPCX; DNR, cells transduced with pLPC-DNR.