Abstract 80: Differential expression of NILCO reveals pathogenesis of human breast cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Introduction: Notch, IL-1 and leptin are known pro-angiogenic factors linked to breast cancer (BC) development, aggressiveness and poor prognosis. We have recently reported leptin as an inducer of IL-1 and Notch in BC cells. Furthermore, we have unveiled a novel signaling crosstalk between these factors: NILCO (Notch, IL-1, leptin crosstalk outcome). Our data show NILCO impacts on VEGF/VEGFR2 levels in BC cells. Objective: In this investigation, we aim to elucidate differences in NILCO relationships to the pathogenesis of triple negative breast cancer (TNBC) as compared to ER positive BC. We hypothesize that the expression of NILCO components correlates to TNBC etiology. Methods: Expression levels of Notch 1, 4, Jagged 1, DLL4, VEGF/VEGFR2 (FLK-1), Ob, Ob-R and IL-1R tI were examined by immunohistochemistry (IHC) in tissue microarrays (n=75/duplicate from Pantomics, Inc.) BC samples included normal/hyperplastic specimens (n=3), fibroadenomas (n=2), invasive ductal carcinomas (n=62; 13 were TNBC: ER-, PR- and HER2/neu-), ductal carcinomas in situ (n=2) and Paget's disease (n=1). IHC evaluations were conducted by two independent observers using semi-quantitative analysis of staining [HSCORE = ∑pi (i + 1), where “i’” is the intensity of staining with a value of 1, 2 or 3 (weak, moderate or strong, respectively) and ‘pi’ is the percentage of stained cells for each intensity]. The following cell lines: TNBC (MDA-MB231 and HCC1806) and ER+ (T47D and MCF-7) were treated with increasing doses of human leptin; leptin peptide receptor antagonist, LPrA2 and a γ-secretase inhibitor (DAPT: Notch pathway inhibitor). After treatments, NILCO and targets were determined by western blot (WB) and ELISA. Results: Data from BC tissue array showed NILCO components were present in the majority of samples. However, lower expression of Notch1, leptin and IL-1R tI was found in non-malignant tissues. In general, TNBC overexpressed Notch1/leptin as compared to ER positive BC. ELISA and WB analysis of cell lysates revealed that leptin increased NILCO component/activation and targets in a dose-dependent manner. Both DAPT and LPrA2 reduced leptin's effects on NILCO. Conclusions: These results support the hypothesis that NILCO may play an important role in BC pathogenesis. [This work was supported in part by NIH/NCI1SC1CA138658-03; NIH/ARRA/3SC1CA138658-02S1 and the Georgia Cancer Coalition Distinguished Cancer Scholar Award (to RRGP); CREDO (MSCR) 2R25RR017694-06A1 to L.S.C; the Morehouse School of Medicine (MSM) MBRS RISE Program (NIH/NIGMS 506 GM08248) to T.Z.M; Blacksone Academy, NIH/NIDDK Step-up HS Research Program: Short-Term Education Program for Underrepresented Persons to K.W. and facilities and support services at Morehouse School of Medicine (NIH RR03034 and 1C06 RR18386)]. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 80. doi:1538-7445.AM2012-80