Noggin, impact on in vitro cell growth, expression pattern and the prognostic value in breast cancer.

Abstract

Abstract Abstract #2084 Background: Noggin, a BMP (bone morphogenetic proteins) antagonist, has been demonstrated to play critical roles in regulation of biological functions of BMPs, members of the TGF-β superfamily and known regulators of bone metastasis in solid tumours including breast cancer. We have recently reported that the presence of endogenous noggin in cancer cells is a pivotal factor that governs the cells response to stimulation by bone morphogenetic protein, for example BMP-7. However, the role of noggin in breast cancer remains unclear. We presently investigated the role of Noggin in breast cancer cells and the pattern of expression in clinical breast tumours.
 Methods: The expression of Noggin mRNA and presence of Noggin protein was examined in a cohort of human breast cancer specimens (normal, n=33; cancer, n=112), using both quantitative real time PCR and immunohitochemical staining, respectively. The full-length human Noggin was cloned into a mammalian expression plasmid vector (pEF/His TOPO TA plasmid vector). The constructed Noggin expressing constructs were then transfected into breast cancer cells (MDA-MB-231). The expression of Noggin in the transfected cells was determined using RT-PCR and western blot. The effect on growth of MDA-MB-231 cells by Noggin was investigated using an in vitro growth assay.
 Results: Immunohistochemical staining revealed that Noggin protein was abundant in the cytoplasmic region of normal epithelial cells. Reduced staining of Noggin in breast cancer cells was seen when compared to normal breast tissue. Quantitative real time PCR further demonstrated that the decreasing Noggin expression correlated to poor prognosis, in that patients who remained disease-free showed a higher levels of the transcript (11113±3612) compared with those who had a poor clinical outcome (with metastasis and mortality, 6420±2241). Kaplan-Meier survival analysis showed that patients with high Noggin level had a longer survival (134.4 (121.3-147.5 - 95%CI) months) that those with low levels (102.8 (80.8-124.8) months). The absorbance of MDA-MB-231 Noggin over-expressing (MDA-MB-231Nogginexp) cells of Day 5 is 1.07±0.13, p<0.01 vs both MDA-MB-231 wild type (MDA-MB-231WT, 1.54±0.08) and empty vector control (MDA-MB-231pEF/His, 1.72±0.17).
 Conclusions: Noggin inhibits the growth of breast cancer cells and has a pattern of expression in that decreased Noggin expression correlates to poor prognosis of breast cancer patients. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2084.