Abstract 1031: Single-cell analysis reveals a possibility of epithelial to circulating tumor cell transition (ECT) when tumor cells enter into the bloodstream

Abstract

Tumor cells face the enviormental changes when leave tumor tissue enter into bloodstream. The environmental changes stimulate tumor cells to adapt the new enviorments with cell functional changes. Epithelial to mesenchymal transition (EMT) is well known and it explains the changes relatively in a portion of the circuating tumor cells (CTC) and in the relative later stage. We use the single-cell molecular analysis on house keeping genes, apoptosis genes, metabolism genes, Epithelial genes, EMT genes, metastasis genes, stem cell genes, and proliferation genes. The results reveal that less than half of individual CTCs express normal level of house keeping genes; apoptosis genes are not expressed at the normal level (reduced or not detectable) in the CTCs without house keeping genes expression; the expression of metabolism genes are relatively low especially in the CTCs without GAPDH expression; the expression level of Epithelial genes are low and the EpCAM and KRT7 are undetectable in most CTCs, but KRT8/18/19 are remaining high expression in the CTCs with GAPDH expressed; EMT genes of VIM, Twist1, MMP-2, TGFB1 are highly expressed in CTCs with GAPDH expressed but no or low expression in the CTCs without GAPDH expression; the expression of metastasis genes are relatively high in the CTCs with GAPDH expressed, but not in the CTCs without the expression of GAPDH; the expression of CD44, CD24, Bmi1, Oct-4, CXCR4, CD9, CXCL2, MAPK14 are highly expressed in the CTCs with GAPDH expressed but not in the CTCs without GAPDH expression; CD44 expressed in some CTCs with higher level than CD24, but much more individual CTCs (with GAPDH expressed) showed higher expression of CD24 than that of CD44 per single-cell level; the expression of proliferation genes are reduced in the CTCs with GAPDH expressed and not detectable in the CTCs without GAPDH expression. Based on the results, we hypthesize Epithelial to circulating transition (ECT) at the early stage after the tumor cells enter into bloodstream and followed by CMT (circulating to mesenchymal transition and then MEC (mesenchymal to epithelial transition) . The ECT may includes the cell changes related to surviving, metabolism level, remaining the characteristics of metastatsis, stem cell signatures, Epithelial related genes and EMT related genes, proliferation genes and others. Studying the early changes of tumor cells enter into bloodstream maybe very improtant for gaining the understanding of the characteristics of survival cells and metastatic tumor cells and also important for basic research and clinical applications. Note: This abstract was not presented at the meeting. Citation Format: Glenn Deng, Stefanie Jeffrey. Single-cell analysis reveals a possibility of epithelial to circulating tumor cell transition (ECT) when tumor cells enter into the bloodstream [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 1031.