Gunjal Pranesh, Pedziwiatr Daniel, Ismail Ahmed A, Kakar Sham S, Ratajczak Mariusz Z
Stem Cell Institute at James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA.
J Cancer Stem Cell Res. 2015;3. doi: 10.14343/jcscr.2015.3e1004. Epub 2015 Feb 27.
It has been proposed that established cell lines contain populations of cancer stem cells (CSCs), which are responsible for expansion of these cell lines and their metastatic potential. To address this issue better, we employed a human ovarian cancer cell line, A2780, and sorted cells according to the postulated highly mestatatic cancer stem cell phenotype, CD24CD44, and the less-metastatic CD24CD44 and CD24CD44 phenotypes. These cells were employed in chemotaxis assays to migrate in response to conditioned media harvested from bone marrow or liver cells damaged by irradiation and in assays to grow tumors after injection into immunodeficient mice. We also sorted single cells expressing all three phenotypes by FACS and expanded them to grow clones. We found that the CD24CD44 cells are a highly migratory population compared with CD24CD44 and CD24CD44 cells and were seeded in higher numbers in murine bone marrow and liver after intravenous injection. Most importantly, we observed that singly sorted cells efficiently expanded ex vivo into cell populations that represented all phenotypes of the parental cell line. Thus, our data indicate that cells expressing a certain set of markers, e.g., CD24, have at any given moment a higher potential to migrate and metastasize. However, cells that are CD24-negative, if expanded from a singly sorted cell, may give rise to cells containing all of the markers, including CD24. Based on this finding, we propose that the CSC phenotype in cell lines fluctuates with cell expansion.
有人提出，已建立的细胞系包含癌症干细胞（CSC）群体，这些细胞系的扩增及其转移潜能都由它们负责。为了更好地解决这个问题，我们使用了一种人卵巢癌细胞系A2780，并根据假定的高转移癌症干细胞表型CD24⁻CD44⁺以及低转移的CD24⁺CD44⁺和CD24⁺CD44⁻表型对细胞进行分选。这些细胞被用于趋化性分析，以响应从受辐射损伤的骨髓或肝细胞收获的条件培养基进行迁移，并用于在注射到免疫缺陷小鼠后进行肿瘤生长分析。我们还通过荧光激活细胞分选术（FACS）对表达所有三种表型的单细胞进行分选，并将它们扩增以形成克隆。我们发现，与CD24⁺CD44⁺和CD24⁺CD44⁻细胞相比，CD24⁻CD44⁺细胞是一个高度迁移的群体，静脉注射后在小鼠骨髓和肝脏中接种的数量更多。最重要的是，我们观察到单个分选的细胞在体外能有效地扩增为代表亲代细胞系所有表型的细胞群体。因此，我们的数据表明，表达一组特定标志物（例如CD24）的细胞在任何给定时刻都具有更高的迁移和转移潜能。然而，如果从单个分选的细胞扩增而来，CD24阴性的细胞可能会产生包含所有标志物（包括CD24）的细胞。基于这一发现，我们提出细胞系中的CSC表型会随着细胞扩增而波动。
