Runx3/Pebp2alphaC null mouse gastric mucosa exhibits hyperplasias due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to growth-inhibitory and apoptosis-inducing action of TGF-beta, indicating that Runx3 is a major growth regulator of gastric epithelial cells. Between 45% and 60% of human gastric cancer cells do not significantly express RUNX3 due to hemizygous deletion and hypermethylation of the RUNX3 promoter region. Tumorigenicity of human gastric cancer cell lines in nude mice was inversely related to their level of RUNX3 expression, and a mutation (R122C) occurring within the conserved Runt domain abolished the tumor-suppressive effect of RUNX3, suggesting that a lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer.

Loss of E-cadherin (E-cad) triggers invasion, metastasis, and dedifferentiation in various epithelial carcinomas. Recently, it has been reported that two transcription factors, Snail and SIP1 (Smad interacting protein 1), directly repress transcription of the E-cad gene by binding E-box on E-cad promoter. Our aim is to solve the molecular mechanism of Snail and SIP1 in hepatocellular carcinoma (HCC). We first showed an inverse correlation between E-cad and Snail/SIP 1 expression among five HCC lines with different phenotypes. The result indicated that undifferentiated, but not differentiated type expressed Snail/SIP1. Then, we established transfectants stably expressing Snail and SIP1 in two differentiated cells with E-cad expression. Suppressed expression of E-cad, morphologic change into fibroblastoid feature, and remarkable acceleration of invasion activity were observed in the transfectants. In reverse transcriptionpolymerase chain reaction series of genes relating to motility and invasion, we demonstrated striking evidence that matrix metalloproteinase (MMP-1), MMP-2, MMP-7, and MT1-MMP expressions were strongly upregulated by Snail. On the other hand, MMP-1, MMP-2, and MT1-MMP expressions were enhanced by SIP1 transfection, however, the intensity was weaker than that in Snail transfection. In conclusion, Snail or SIP1 expression may be induced during HCC progression, where Snail/SIP1 directly represses E-cad gene transcription and activates cancer invasion via the upregulation of the MMP gene family.

No abstract

No abstract

No abstract

No abstract

The in situ tissue-engineered esophagus can successfully replace the intrathoracic esophagus, and this procedure may offer a promising surgical approach to esophageal diseases.

No abstract