Esophageal Cancer Stem Cells Research Articles

Quiescence and attenuated DNA damage response promote survival of esophageal cancer stem cells

Accumulating evidence indicates cancer stem cells (CSCs) possess the capability to resist DNA-damage induced cell death, whereas the mechanism is largely unknown. Here we show that cell cycle status and DNA damage response (DDR) in CSCs probably contribute to their survival in genotoxic insults. In this study, we isolated esophageal cancer stem cells (ECSCs) from esophageal cancer cell line EC9706 by side-population (SP) phenotype through flow cytometry and found that ECSCs preferentially stay quiescent as compared to the non-ECSCs and are more resistant to DNA damage agents. Further study revealed that ECSCs express a lower level of EGFR, phosphoralated Stat3, and c-Myc, yet abnormally upregulated p27. More interestingly, different from non-ECSCs, when suffering DNA damage agents, ECSCs showed attenuated DDR, as well as declined DNA repair potential. These data indicated ECSCs probably employed an impaired DDR to handle severe genomic insults. Conclusively, we infer that the damage-resistance ability of ECSCs is likely attributed to their slow-cycling status and avoidance of apoptosis or senescence triggered by an excessive DDR.

Identification and characterization of stemlike cells in human esophageal adenocarcinoma and normal epithelial cell lines

Recent studies have suggested that human solid tumors may contain subpopulations of cancer stem cells with the capacity for self-renewal and the potential to initiate and maintain tumor growth. The aim of this study was to use human esophageal cell lines to identify and characterize putative esophageal cancer stem cell populations. To enrich stemlike cells, Het-1A (derived from immortalized normal esophageal epithelium), OE33, and JH-EsoAd1 (each derived from primary esophageal adenocarcinomas) were cultured using serum-free media to form spheres. A comprehensive analysis of parent and spheroid cells was performed by flow cytometry, Western blot analysis, immunohistochemistry and polymerase chain reaction array to study cancer stem cell-related genes, colony formation assays to assess clonogenicity, xenotransplantation to assess tumorigenicity, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays to assess chemosensitivity to 5-fluorouracil and cisplatin. For all cell lines, clonogenicity, tumorigenicity, and chemoresistance to 5-fluorouracil and cisplatin were significantly higher than for spheroid cells compared with parent cells. Spheroids exhibited an increased frequency of cells expressing integrin α6(bri)/CD71(dim), and Achaete-scute complex homolog 2 messenger RNA and protein were also significantly overexpressed in spheroid cells compared with parent cells. The higher clonogenicity, tumorigenicity, and drug resistance exhibited by spheroids derived from Het-1A, OE33, and JH-EsoAd1 reflects an enrichment of stemlike cell populations within each esophageal cell line. Esophageal cells enriched for integrin α6(bri)/CD71(dim) and/or overexpressing Achaete-scute complex homolog 2 would appear to represent at least a subpopulation of stemlike cells in Het-1A, OE33, and JH-EsoAd1.

Abstract 2140: Assessment of curcumin-induced apoptosis and detection of cancer stem cell-like subpopulations in human esophageal cancer cell lines

Abstract Curcumin, the major active ingredient of turmeric, has been shown to kill several types of malignant cells while it has little or no effect on normal cells, suggesting that it may be an effective therapeutic agent. Although some studies have investigated curcumin effects on esophageal cancer cell lines, no studies have characterized the curcumin-surviving cells, an important population that might show resistance to curcumin. There is increasing evidence that many cancers contain subpopulations that display stem cell characteristics. Cancer stem cells (CSCs) appear to play a central role in tumorigenesis, recurrence, metastasis, and resistance to cancer therapy. The aims of the current study were to assess curcumin-induced cell death and detect CSC subpopulations in six human esophageal cancer cell lines (TE-1, TE-8, KY-5, KY-10, YES-1, and YES-2). Aldehyde dehydrogenase-1A1 (ALDH1A1) expression was used as one marker for CSCs. To evaluate curcumin effects, the cell lines were exposed to 20-80 µM of curcumin for 30 hrs. In all six lines, cell death increased continuously with increasing dosage of curcumin based on a standard crystal violet assay. No cells survived at 80 µM, and the range of cell death across the six cell lines was 66 to 89% at 60 µM. To characterize the progeny of cells that survived curcumin, 1×105 cells from each line were exposed to 40-60 µM curcumin for 30 hours, and the colonies that formed from surviving cells were counted. The number of colonies present after 60 µM treatment varied between the cell lines (ranging from 8 to more than one hundred). The Yes-2 cell line did not survive at 60 µM, but produced 15 colonies after 40 µM treatment. Staining with an antibody against ALDH1A1 was used to compare CSC-like subpopulations within and among the original cells lines as well as cell lines established from the curcumin-treated lines. All cell lines were heterogeneous with respect to ALDH1A1 staining, revealing two subpopulations within each line. The intensity of staining was at least two times higher in the population considered to be CSCs. Interestingly, the curcumin-surviving cell lines showed a significant loss in the high-staining population compared to the untreated cells (T-test, p<0.05), suggesting that curcumin not only can kill cancer cells but also CSCs. Thus, esophageal CSCs appear to be highly sensitive to curcumin. Therefore, curcumin may be a more effective compound for esophageal cancer therapy than other chemotherapeutic agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2140. doi:10.1158/1538-7445.AM2011-2140

* LNA-Modified oligonucleotides targeting mRNA of dicer in pegylated colloidal nanoparticles with linked ABS against CD44 eradicate esophageal cancer stem cells (ECSC) by induction of PCD after inhibition of oncomir machinery

IntroductionMetastatic oesophageal squamous cell Ca (ESCC) is incurable due to chemoresistance caused by cancer stem cells due to overexpression of oncomirs which upregulate oncogenes and hypermethylation in CpG islands which...

Cancer Stem Cell Radioresistance and Enrichment: Where Frontline Radiation Therapy May Fail in Lung and Esophageal Cancers

Many studies have highlighted the role cancer stem cells (CSC) play in the development and progression of various types of cancer including lung and esophageal cancer. More recently, it has been proposed that the presence of CSCs affects treatment efficacy and patient prognosis. In reviewing this new area of cancer biology, we will give an overview of the current literature regarding lung and esophageal CSCs and radioresistance of CSC, and discuss the potential therapeutic applications of these findings.