Abstract 3380: Comparison proteome analysis of scirrhous gastric carcinoma stem cell-like SP and hypoxia-resistant cell lines

Abstract

Abstract Intro Cancer stem cells (CSCs) are considered to be responsible for cancer metastasis, and hypoxia is supposed to be an important regulator of CSCs differentiation. Furthermore, tumor hypoxia was reported to be associated with more aggressive tumor phenotypes such as high metastatic ability and resistance to various anti-cancer therapies which may lead to a poorer prognosis. This raises the question of whether there might be proteins representing similar alterations which are responsible for the correlation between hypoxic and CSCs phenotypes. We have established a diffuse-type of gastric carcinoma cell line (OCUM-12), and a hypoxia-resistant cancer cell line (OCUM-12/Hypo) cloned from parent OCUM-12 cells by continuous exposure to 1% oxygen. The side population (SP), as evaluated by a flow cytometric analysis using Hoechst 33342, has been known as CSC-rich population. To investigate and compare the proteomes of the hypoxic (OCUM-12/Hypo), stem cell (OCUM-12SP) and parent OCUM-12 diffuse-type gastric carcinoma cell lines, protein lysates from those cell lines were analyzed using QSTAR Elite LC MS/MS. Method Triplicate pooled samples (10 ug protein each) from stomach cancer cell lines were prepared and labeled with iTRAQ reagents. MS/MS data were searched against the Swiss Protein database (HUMAN) using ProteinPilot™ 2.0 software (AB Sciex). The Ingenuity Pathway analysis program was utilized, to assign biological significance, and to identify networks of interacting differentially expressed proteins, functional groups and pathways. Result In both OCUM-12SP and OCUM-12/Hypo cells, significant overexpression of Wnt signaling pathway was obvious. Furthermore, elevation of MTHFD1, a protein controlling histidine and purine nucleotide metabolism, cytokeratins 18 (CK18), and 19 (CK19) regulating cell cycle, apoptosis and angiogenesis, transcriptional regulator ANP32A, and cellular chaperones heat shock proteins A9 and STIP was observed as compared to the parent OCUM-12 cell line. Furthermore, anterior gradient homolog 2 (AGR2)was down-regulated in both cell lines. Conclusion Wnt signal, MTHFD1, CK18, CK19, ANP32A, HSPA9 and STIP, AGR2 might be responsible for the stem-like phenotype, hypoxia resistance and higher invasiveness of gastric cancer. 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 3380. doi:1538-7445.AM2012-3380