Previ ously, we identified the loss selleck compound of membranous B catenin in LM8 murine osteosarcoma cells, which possess ex tremely high metastatic potential to the lung. Hugh et al. reported that loss of membranous B catenin occurred commonly in primary colorectal can cers with metastatic potential and in the corresponding colorectal liver metastases. Thus, loss of B catenin at the cell surface seems to be associated with tumor metasta sis. However, the association of the level of cytoplasmic B catenin with the metastatic potential of tumor cells re mains unclear. Genistein is an isoflavone found in dried and green soybeans and soy products, such as soy sauce, miso, and tofu. Experi mental studies have shown that genistein inhibits the growth, invasion, and metastasis of tumors in vivo and in vitro.

Previously, we found that treatment of LM8 cells with genistein inhibited cell proliferation, de creased the expression and secretion of matrix metallo proteinase 2, which plays a pivotal role in tumor growth, invasion and metastasis, and de creased cell invasive and motile potential. Moreover, this treatment induced morphological changes, markedly decreased the formation of multilayer masses, and in creased the level of osteocalcin mRNA. Thus, genistein may induce the differentiation of LM8 cells. These findings raise the question of whether genistein treated LM8 cells have the potential to metastasize to the lung in vivo. To explore the above question, untreated and genistein treated LM8 cells were subcutaneously inoculated into the backs of nude mice, and whether they developed meta static tumors in the lung was histochemically examined.

The main purpose of this study is to investigate the associ ation of the expression of cytoplasmic B catenin in pri mary tumor cells with metastatic potential. Therefore, the expression of B catenin within the primary tumor was immunohistochemically examined. In addition, whether the metastatic potential of primary tumor cells is associ ated with the expression of MMP 2 was also examined. Results The expression of B catenin in untreated and genistein treated LM8 cells LM8 cells were treated for 3 days without or with 50 uM genistein and fixed with ethanol. The expression of B catenin in untreated and genistein treated LM8 cells was immunohistochemically examined.

In untreated LM8 cells, positive B catenin immunostaining was observed in the cytoplasm and/or nucleus, and the intensity of immunostaining in the cytoplasm GSK-3 was weak. In genistein treated LM8 cells, positive B catenin immu nostaining was predominantly observed in the cytoplasm, and the intensity of immunostaining was stronger than that observed in untreated LM8 cells. These findings indicate that genistein treated LM8 cells expressed higher levels of cytoplasmic B catenin than untreated LM8 cells.