During carcinogenesis, NF-kappaB mediates processes associated with deregulation of the normal control of proliferation, angiogenesis, and metastasis. Thus, suppression of NF-kappaB has been linked with chemoprevention of cancer. Accumulating findings reveal that heat shock protein 90 (HSP90) is a molecular chaperone and a component of the IkappaB kinase (IKK) complex that plays a central role in NF-kappaB activation. HSP90 also stabilizes key proteins involved in cell cycle control and apoptosis signaling. We have determined whether the exogenous administration of isoflavone-deprived soy peptide prevents 7,12-dimethylbenz[alpha]anthracene (DMBA)-induced rat mammary tumorigenesis and investigated the mechanism of action. Dietary administration of soy peptide (3.3 g/rat/day) significantly reduced the incidence of ductal carcinomas (50%), the number of tumors per multiple tumor-bearing rats (49%; P < 0.05), and extended the latency period of tumor development (8.07 +/- 0.92 weeks) compared to control diet animals (10.80 +/- 1.30; P < 0.05). Our results have further demonstrated that soy peptide (1) dramatically inhibits the expression of HSP90, thereby suppressing signaling pathway leading to NF-kappaB activation; (2) induces expression of p21, p53, and caspase-3 proteins; and (3) inhibits expression of VEGF. In agreement with our in vivo data, soy peptide treatment inhibited the growth of human breast MCF-7 tumor cells in a dose-dependent manner and induced apoptosis. Taken together, our in vivo and in vitro results suggest chemopreventive and tumor suppressive functions of isoflavone-deprived soy peptide by inducing growth arrest and apoptosis.
9,10-Dimethyl-1,2-benzanthracene ; Adenocarcinoma/*prevention & control ; Animals ; Apoptosis/*drug effects ; Breast Neoplasms/chemically induced/pathology/*prevention & control ; Cell Line, Tumor ; Chemoprevention ; Female ; Gene Expression Regulation, Neoplastic ; HSP90 Heat-Shock Proteins/genetics/metabolism ; Humans ; Isoflavones/chemistry ; NF-kappa B/genetics/metabolism ; Peptides/chemistry/isolation & purification/therapeutic use ; Rats ; Rats, Sprague-Dawley ; Soybean Proteins/chemistry/*isolation & purification/*therapeutic use ; Soybeans/chemistry

Ovarian cancer is a leading cause of death in women. Early detection of ovarian cancer is essential to decrease mortality. However, the early diagnosis of ovarian cancer is difficult due to a lack of clinical symptoms and suitable molecular diagnostic markers. Thus, identification of meaningful tumor biomarkers with potential clinical application is clearly needed. To search for a biomarker for the early detection of ovarian cancer, we identified human anterior gradient 2 (AGR2) from our systematic analysis of paired normal and ovarian tumor tissue cDNA microarray. We noted a marked overexpression of AGR2 mRNA and protein in early stage mucinous ovarian tumors compared to normal ovarian tissues and serous type ovarian tumors by Western blot analysis and immunohistochemistry. To further elucidate the role of AGR2 in ovarian tumorigenesis, stable 2774 human ovarian cancer cell lines overexpressing AGR2 were established. Forced expression of AGR2 in 2774 cells enhanced the growth and migration of ovarian cancer cells. AGR2 protein was detected in the serum of mucinous ovarian cancer patients by Western blot and ELISA analysis. Thus, AGR2 is a potential biomarker for the diagnosis of mucinous ovarian cancer and an ELISA assay may facilitate the early detection of mucinous ovarian cancer using patient serum.
Cell Line, Tumor ; Cell Movement/physiology ; Cell Proliferation ; Female ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; HEK293 Cells ; Humans ; Ovarian Neoplasms/genetics/*metabolism/pathology ; Proteins/genetics/*metabolism ; Tumor Markers, Biological/blood/*metabolism