Abstract 423: Suppression of endometrial cancer cell migration, invasion, and colony formation by the putative tumor suppressor gene MIIP

Abstract

Abstract Objective: Endometrial carcinoma (EC) is the leading cancer of the female genital tract in the United States and the fourth most common cancer among women after breast, lung, and colorectal cancer. Augmented cell motility, invasion, and proliferation are hallmarks of aggressive EC. We aim to determine whether the recently discovered migration and invasion inhibitory protein (MIIP) gene functions as an inhibitor for these hallmarks in endometrial cancer cells. Methods: We measured MIIP expression by Western blot and quantitative RT-PCR. The effect of MIIP on cell motility and invasion was measured by wound healing and Boyden Chamber transwell assay. The potential anti-tumor function of MIIP was measured by colony formation assay. Whole-genome transcriptome was determined in MIIP overexpressing cells and KEGG pathway analysis was done to determine the key pathways regulated by MIIP. Results: The levels of MIIP mRNA and protein expression were decreased in high-grade EC compared with normal EC tissues. MIIP protein is detectable at low level in the HEC1A cell line but undetectable in the AN3CA and HEC1B cell lines. Knockdown of MIIP expression with siRNA in HEC1A cells significantly increased cell migration when compared with control siRNA treated cells (71.17±3.82 vs. 30.12±1.94, P<0.01). Elevated expression of the MIIP significantly decreased cell migration in AN3CA and HEC1B cells compared with control empty vector-transfected cells (AN3CA: 26.67±1.86 vs. 69.83±2.93, P<0.01; HEC1B: 21.83±2.04 vs. 89.83±5.56, P<0.01). The invasion of the MIIP-knocked-down HEC1A cells was significantly increased compared with control (50.67±1.86 vs.5.83±1.47, P<0.01). Consistently, cell invasion was significantly decreased in MIIP overexpressed cells compared with control HEC1B cells (18.33±2.33 vs.43.17±4.07, P<0.01). Overexpression of MIIP in EC cell lines led to reduced levels of matrix metalloprotease 2 and 9. Further, transfection with the MIIP expression vector significantly reduced colony formation by 73.6% in HEC1A compared with empty vector-transfected cells (52.25±3.30 vs.13.75±2.87, P<0.01). Gene expression profiling of MIIP overexpressed AN3CA and HEC1B cells and their control cells followed by KEGG pathway analysis showed that MIIP expression regulates TP53 signaling, Jak-STAT signaling, and PI3K/Akt pathways. Conclusions: MIIP may function as a tumor suppressor gene for endometrial cancer and loss of MIIP expression may contribute to increased cell growth and migration/invasion activities in endometrial cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 423.