TGF beta1 and related-Smads contribute to pulmonary metastasis of hepatocellular carcinoma in mice model

Background: Recent studies indicate that Transforming Growth Factor beta (TGF beta) correlated with pulmonary metastasis of cancers. However, the correlation between TGF beta and pulmonary metastasis of hepatocellular carcinoma (HCC) is till unknown. Methods: We detected the in vitro and in vivo expression levels of TGF beta 1/Smads by Real-time PCR and Western blot in MHCC97-H and MHCC97-L cell lines, which are HCC cell lines and have higher and lower pulmonary metastatic potential respectively. Results: TGF beta 1 mRNA level in MHCC97-L tumors were higher than that in MHCC97-H tumors, (2.81 +/- 1.61 vs. 1.24 +/- 0.96, P=0.002), TGF beta 1 protein level in MHCC97-L tumors were also higher than that in MHCC97-H tumors (1.37 +/- 0.95 vs. 0.32 +/- 0.22, P<0.001). In addition, the TGF beta 1 mRNA level positively correlated with pulmonary metastasis, and the relations between TGF beta 1 and Smads were also found (R-2=0.12 and 0.40, respectively). Conclusions: Our results suggest that TGF beta/Smads promote pulmonary metastasis of HCC.