Abstract 2864: MAEA (macrophage erythroblast attacher) suppresses migration, invasion and enhances chemosensitivity in colorectal cancer cell lines
Authors: Lo Jae Ho , Soni Shivani , Tokunaga Ryuma , Battaglin Francesca , Naseem Madiha , Puccini Alberto , Arai Hiroyuki , Ning Tricia , Berger Martin D. , Cao Shu , Zhang Wu , Millstein Josh , Lenz Heinz-Josef 
Published: August 2019

Abstract
Purpose: MAEA, also known as Emp (Erythroblast Macrophage protein), plays an important role in actin cytoskeleton rearrangement in macrophages and erythroid cells. A recent study indicated that down-regulation of MAEA in mouse monocyte macrophage results in abnormal cell motility and higher expression of mitogen-activated protein kinase 1 (MAPK 1) and thymoma viral proto-oncogene 1 (Akt 1). However, the precise mechanism of MAEA in cancer remains unclear. In this study, we examined the role of MAEA in cell motility, invasion and chemosensitivity in colorectal cancer (CRC) cell lines.
Experimental Procedure: CRC cell lines were selected based on MSI/MSS status. MAEA was overexpressed in HCT116, SW480, LoVo, SW626 cell lines using vector pRP[Exp]-EGFP/Puro-CMV&gt;hMAEA[ORF013172]. MAEA expression was quantified by qRT-PCR and immunoblotting. To determine the role of MAEA in migration and invasion, wound closure and transwell invasion assays were performed. Immunofluorescent staining was carried out to study actin cytoskeletal remodeling. The effect of MAEA on chemosensitivity was evaluated by using MTS assay after treatment with 5-FU, oxaliplatin and irinotecan. Both cell motility and DNA repair related genes expression profile were analyzed by human RT2 Profiler PCR array.
Result: Our results showed that up-regulation of MAEA significantly suppressed migration and invasion in HCT116 cell line (MSI, RAS mutant, BRAF wild type, APC wild type). Furthermore, immunofluorescence staining indicated actin cytoskeleton projections were disrupted with up-regulation of MAEA. In MTS assay, MAEA overexpressed HCT116 demonstrated enhanced chemo sensitivity to 5-FU, oxaliplatin, and irrinotecan (35%, 40%, and 40% respectively). PCR array analysis showed significant downregulation of cell motility related genes AKT1, BCAR1, HGF, ITGA4, ITGB3, MAPK1, RHOB, SRC (2.4, 2.4, 50, 9.1, 2.0, 1.56, 2.38, and 2.38 folds respectively). Similarly, DNA repair related genes DMC1, ERCC1, ERCC2, ERCC3, ERCC4, RAD51D, RAD52 were downregulated (1.63, 1.64, 1.56, 1.66, 1.66, 2.0, 1.75 folds respectively).
Conclusion: Our findings show MAEA suppresses migration, invasion and enhances chemo sensitivity to first-line of treatment in colorectal cancer cell lines. Downregulation of both MAPK1 and AKT1 suggests that MAEA may be involved in PI3K-ATK and/or RAS-ERK pathways regulating cell motility and invasion. Downregulation of DNA repair related genes can be a plausible reason for enhanced chemosensitivity in MSI-high CRC cell lines.
Citation Format: Jae Ho Lo, Shivani Soni, Ryuma Tokunaga, Francesca Battaglin, Madiha Naseem, Alberto Puccini, Hiroyuki Arai, Tricia Ning, Martin D. Berger, Shu Cao, Wu Zhang, Josh Millstein, Heinz-Josef Lenz. MAEA (macrophage erythroblast attacher) suppresses migration, invasion and enhances chemosensitivity in colorectal cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2864.