Abstract 3055: Wnt inhibitory factor 1 inhibits cervical cancer cell growth in vitro

Abstract

Abstract Background and Purpose: Cervical cancer is one of the most common malignancies and major causes of death in women worldwide. Aberrant activation of Wnt/β-catenin pathway is associated with various cancers including cervical cancer. Mutations within intracellular components of the Wnt pathway are rare in cervical cancer. We hypothesize that alterations in secreted Wnt antagonists might play a major role in Wnt activation. Here we characterize the status of the Wnt inhibitory factor 1 (WIF1) in cervical cancer cell lines and determined the in vitro effects of WIF1 on cervical cancer cells. Methods: Three cervical cancer cell lines (HeLa, C33A and CC1) were treated with the demethylating agent 5-aza-2′-deoxycytidine (DAC) for 4 days, total RNA was isolated and real-time RT-PCR was performed to determine WIF1 mRNA expression. HeLa cells were transfected simultaneously with either pCI blast (empty vector) or pCI blast-WIF1 using LipoD293 transfection reagent and assessed for cell proliferation and apoptosis. Cell proliferation was determined at different time intervals (24, 48, 72 and 96 h) by hexosaminidase assay. Cell cycle analysis was performed after 72 h by flow cytometry using FACSCalibur analyzer. Caspase 3/7 activity was measured using the Apo-one Homogeneous Caspase-3/7 Assay kit. Results: We demonstrated that WIF1 is down-regulated in cervical cancer cells. Treatment with DAC caused a significant increase in WIF1 mRNA expression in all the cell lines tested compared with vehicle treatment. Furthermore, transfection with a plasmid expressing WIF1 significantly inhibited cervical cancer cell proliferation at all time points studied. To probe the possible mechanisms involved in WIF1 cell growth inhibition, we performed cell cycle analysis and caspase 3/7 assay. Interestingly, cell cycle analysis demonstrated that transfection with WIF1 significantly increased the G2-M cell population and the number of apoptotic cells. In addition, WIF1 significantly induced caspase 3/7 activity suggesting that WIF1 induced apoptosis is mediated through caspase 3/7 activation. Conclusions: Our data suggests that WIF1 is silenced in cervical cancer cells and WIF1 restoration inhibits cervical cancer cell growth by inducing G2-M arrest and apoptosis. This study emphasizes the importance of WIF1 as a potential therapeutic strategy in the treatment of cervical cancer. 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 3055.