Identification Of Cancer Stem Cells Research Articles

Optimized Dosing Schedule Based on Circadian Dynamics of Mouse Breast Cancer Stem Cells Improves the Antitumor Effects of Aldehyde Dehydrogenase Inhibitor.

Although malignant phenotypes of triple-negative breast cancer (TNBC) are subject to circadian alterations, the role of cancer stem cells (CSC) in defining this circadian change remains unclear. CSC are often characterized by high aldehyde dehydrogenase (ALDH) activity, which is associated with the malignancy of cancer cells and is used for identification and isolation of CSC. Here, we show that the population of ALDH-positive cells in a mouse 4T1 breast tumor model exhibits pronounced circadian alterations. Alterations in the number of ALDH-positive cells were generated by time-dependent increases and decreases in the expression of Aldh3a1 Importantly, circadian clock genes were rhythmically expressed in ALDH-negative cells, but not in ALDH-positive cells. Circadian expression of Aldh3a1 in ALDH-positive cells was dependent on the time-dependent release of Wingless-type mmtv integration site family 10a (WNT10a) from ALDH-negative cells. Furthermore, antitumor and antimetastatic effects of ALDH inhibitor N,N-diethylaminobenzaldehyde were enhanced by administration at the time of day when ALDH activity was increased in 4T1 tumor cells. Our findings reveal a new role for the circadian clock within the tumor microenvironment in regulating the circadian dynamics of CSC. These results should enable the development of novel therapeutic strategies for treatment of TNBC with ALDH inhibitors.Significance: This seminal report reveals that circadian dynamics of CSC are regulated by the tumor microenvironment and provides a proof of principle of its implication for chronotherapy in TNBC. Cancer Res; 78(13); 3698-708. ©2018 AACR.

Curcumin attenuates resistance to irinotecan via induction of apoptosis of cancer stem cells in chemoresistant colon cancer cells.

Resistance to conventional chemotherapeutic agents, including irinotecan (CPT‑11), 5-fluorouracil and capecitabine is a major cause for therapeutic failure in patients with colorectal cancer (CRC). Increasing evidence has demonstrated that cancer cells exhibiting stem cell-like characteristics are associated with the development of resistance to chemotherapeutic agents. As a plant polyphenol, curcumin has been demonstrated to have the ability to ameliorate resistance of CRC to chemotherapeutic agents, but the associations among curcumin, cancer stem cells (CSCs) and chemoresistance of CRC remain unclear. The present study established a CPT‑11-resistant colon cancer cell line, LoVo/CPT‑11 cells, and detected the expression levels of CSC identification markers [cluster of differentiation (CD)44, CD133, epithelial cell adhesion molecule (EpCAM) and CD24] in parental cells and CPT‑11-resistant cells. It was revealed that the expression levels of the colon CSC markers in LoVo/CPT‑11 cells were significantly higher compared those in parental cells at the mRNA and protein level. The effect of curcumin on the chemoresistance to CPT‑11 and the expression levels of CSC identification markers in LoVo/CPT‑11 cells separately treated with curcumin and CPT‑11 were further investigated. The results revealed that curcumin significantly attenuated chemoresistance to CPT‑11, and treatment with curcumin resulted in a significant reduction of the expression levels of CSC identification markers. Furthermore, a tumor sphere formation assay was used to enrich colon CSCs from LoVo/CPT‑11 cells, and demonstrated that curcumin efficiently diminished the traits of colon CSCs, as evidenced by the inability to form tumor spheres, the reduction in the expression of CSC identification markers, and apoptosis-induced effects on sphere-forming cells treated with curcumin alone or in combination with CPT‑11. Altogether, the present data demonstrated that curcumin attenuated resistance to chemotherapeutic drugs through induction of apoptosis of CSCs among colon cancer cells. These findings may provide novel evidence for the therapeutic application of curcumin in CRC intervention.

Assessing stemness and proliferation properties of the newly established colon cancer 'stem' cell line, CSC480 and novel approaches to identify dormant cancer cells.

To date two questions that remain unanswered regarding cancer are the following: i)how is it initiated, and ii)what is the role that cancer stem cells (CSCs) play in the disease process? Understanding the biology of CSCs and how they are generated is pivotal for the development of successful treatment regimens. To date, the lack of a representative cell model has prevented the successful identification and eradication of CSCs invivo. The current methods of CSC identification are dependent on the protocol used to generate these cells, which has introduced variation and made the identification process more complicated. Furthermore, the list of possible markers is increasing in complexity. This is further confounded by the fact that there is insufficient information to determine whether the cells these markers detect are truly self‑renewing stem cells or, instead, progenitor cells. In the present study, we investigated a novel cell line model, CSC480, which can be employed to assess CSC markers and for testing novel therapeutic regimens. CSC480 cells have been revealed to express markers of CSCs such as CD44, ALDH1 and Sox2, that have lower expression in the SW480 cell line. CSC480 cells also expressed higher levels of the cancer resistance marker, ABCG2 and had higher proliferative and growth capacity than SW480 cells. In the present study, we also evaluated a novel approach to identify different cell types present in heterogeneous cancer cell populations according to their proliferative ability using the proliferation marker 5‑ethynyl‑2'‑deoxyuridine (EdU). Furthermore, using EdU, we identified dormant cells with a modified label‑retaining cell (LRC) protocol. Through this novel LRC method, we assessed newly discovered markers of stemness to ascertain their capability to identify quiescent from dividing CSCs. In conclusion, the CSC480 cell line was an important model to be used in unravelling the underlying mechanisms that control fast‑dividing and partially self‑renewing stem cells (SCs) that may give rise to cancer.

PDE5 inhibition eliminates cancer stem cells via induction of PKA signaling

Cancer stem cells (CSCs) are involved in metastasis and resistance development, thus affecting anticancer therapy efficacy. The underlying pathways required for CSC maintenance and survival are not fully understood and only a limited number of treatment strategies to specifically target CSCs have been identified. To identify novel CSC targeting compounds, we here set-up an aldehyde dehydrogenase (ALDH)-based phenotypic screening system that allows for an automated and standardized identification of CSCs. By staining cancer cells for ALDH activity and applying high-content-based single-cell population analysis, the proportion of a potential CSC subpopulation with significantly higher ALDH activity (ALDHhigh) can be quantified in a heterogeneous cell population. We confirmed high ALDH activity as surrogate marker for the CSC subpopulation in vitro and validated Wnt signaling as an essential factor for the maintenance of CSCs in SUM149 breast cancer cells. In a small molecule screen, we identified phosphodiesterase type 5 (PDE5) inhibition as potential strategy to target CSC maintenance and survival in multiple cancer cell lines. CSC elimination by PDE5 inhibition was not dependent on PKG signaling, and we suggest a novel mechanism in which PDE5 inhibition leads to elevated cGMP levels that stimulate cAMP/PKA signaling to eliminate CSCs.

In vitro and in vivo characterization of stem-like cells from canine osteosarcoma and assessment of drug sensitivity

Cancer stem cell (CSC) self-renewing and drug resistance cause treatment failure and tumor recurrence. Osteosarcoma is an aggressive bone tumor characterized by biological and molecular heterogeneity, possibly dependent on CSCs. CSC identification in osteosarcoma and their efficient targeting are still open questions. Spontaneous canine osteosarcoma shares clinical and biological features with the human tumors, representing a model for translational studies. We characterized three CSC-enriched canine osteosarcoma cultures. In serum-free conditions, these CSC cultures grow as anchorage-independent spheroids, show mesenchymal-like properties and in vivo tumorigenicity, recapitulating the heterogeneity of the original osteosarcoma. Osteosarcoma CSCs express stem-related factors (Sox2, Oct4, CD133) and chemokine receptors and ligands (CXCR4, CXCL12) involved in tumor proliferation and self-renewal. Standard drugs for osteosarcoma treatment (doxorubicin and cisplatin) affected CSC-enriched and parental primary cultures, showing different efficacy within tumors. Moreover, metformin, a type-2 diabetes drug, significantly inhibits osteosarcoma CSC viability, migration and self-renewal and, in co-treatment with doxorubicin and cisplatin, enhances drug cytotoxicity. Collectively, we demonstrate that canine osteosarcoma primary cultures contain CSCs exhibiting distinctive sensitivity to anticancer agents, as a reliable experimental model to assay drug efficacy. We also provide proof-of-principle of metformin efficacy, alone or in combination, as pharmacological strategy to target osteosarcoma CSCs.

Identification of Cancer Stem Cells in Esophageal Adenocarcinoma.

Cancer stem cells (CSCs) are a subpopulation of cancer cells that have the ability to self-renew and to generate differentiated cells of various lineages. Due to their specific morphological and biological features, they are often resistant to therapy and in turn lead to metastasis and cancer recurrence. Because of their crucial roles in carcinogenesis and patient prognosis, identification and isolation of CSCs have become an important part of improved cancer management regime. Isolation, characterization, and development of targeted therapy against CSCs have potential efficacy in treating esophageal cancer. In addition, CSCs can act as a predictive tool for chemoradiotherapy response in esophageal adenocarcinoma. Different methods including functional assays, cell sorting using various intracellular, and cell surface markers and xenotransplantation techniques are used for the identification and separation of CSCs in different cancers. None of these methods solely can guarantee complete isolation of CSC population, thus a combination of methods could be used for reliable detection and isolation of CSCs. Here, we describe the identification and isolation of CSCs from esophageal adenocarcinoma cells by cell sorting after Hoechst 33342 staining followed by in vitro functional assays, and in vivo xenograft techniques.

Lung cancer stem cells – the role in pathogenesis and progressive growth of cancer

Lung cancer is the main cause of cancer death worldwide. Rapid accurate diagnosis, recognition of risk factors and improvement of treatment efficacy represent the main challenges. An advanced stage of the disease at the time of diagnosis, observed in the majority of cases, makes the introduction of radical treatment impossible or ineffective. Immunotherapy was a breakthrough in achieving long-term survival in recent years. The reason for developing this type of treatment is to know the interaction between the host cells and tumor cells. Cancer stem cells theory is increasingly gaining greater significance in the world. The biological heterogeneity of lung cancer may be due to the presence of a small percentage of cancer stem cells (CSCs). CSCs are the results of genetic and epigenetic changes in normal stem cells, progenitor cells or differentiated cells. CSCs are functionally defined by their unlimited self-renewal capacity, multiple differentiation and their ability to imitate tumors. It is believed that CSCs determine unrestricted growth of tumors and their different morphology. Their ability to self-renew can be the cause of relapses even after long periods of remission. CSCs reside in niches, where they receive signals for differentiation and proliferation process. The identification of CSCs is based on the presence of specific molecules (CD133, CD44, CD90, ALDH, EpCAM). An important feature of CSCs is their resistance to conventional cancer treatment: radio therapy and chemotherapy. Presumably, CSCs are responsible for the synthesis of immunosuppressive particles, and recruiting other molecules, which have immunosuppressive properties. The paper presents the current state of knowledge on CSCs in lung cancer detailing adenocarcinoma.

Tracing and targeting cancer stem cells: New venture for personalized molecular cancer therapy.

Tumors consist of a mixture of heterogeneous cell types. Cancer stem cells (CSCs) are a minor sub-population within the bulk cancer fraction which has been found to reconstitute and propagate the disease and to be frequently resistant to chemotherapy, irradiation, cytotoxic drugs and probably also against immune attack. CSCs are considered as the seeds of tumor recurrence, driving force of tumorigenesis and metastases. This underlines the urgent need for innovative methods to identify and target CSCs. However, the role and existence of CSCs in therapy resistance and cancer recurrence remains a topic of intense debate. The underlying biological properties of the tumor stem cells are extremely dependent on numerous signals, and the targeted inhibition of these stem cell signaling pathways is one of the promising approaches of the new antitumor therapy approaches. This perspective review article summarizes the novel methods of tracing CSCs and discusses the hallmarks of CSC identification influenced by the microenvironment or by having imperfect detection markers. In addition, explains the known molecular mechanisms of therapy resistance in CSCs as reliable and clinically predictive markers that could enable the use of new targeted antitumor therapy in the sense of personalized medicine.

Membrane-bound full-length Sonic Hedgehog identifies cancer stem cells in human non-small cell lung cancer.

The mechanism of Sonic Hedgehog (Shh) pathway activation in non-small cell lung cancer (NSCLC) is poorly described. Using an antibody against the Shh C-terminal domain, we found a small population of Shh-positive (Shh+) cells in NSCLC cells. The objective of this study was to characterize these Shh+ cells. Shh+ and Shh- cells were sorted by using Fluorescence Activated Cell Sorting (FACS) on 12 commercial NSCLC cell lines. Functional analyses on sorted cells were performed with gene expression assays (qRT-PCR and microarray) and cells were treated with cytotoxic chemotherapy and a targeted inhibitor of Shh signaling (GDC0449). We used in vivo models of nude mice inoculated with Shh+ and Shh- sorted cells and drug-treated cells. Finally, we confirmed our results in fresh human NSCLC samples (n=48) paired with normal lung tissue. We found that Shh+ cells produced an uncleaved, full-length Shh protein detected on the membranes of these cells. Shh+ cells exerted a paracrine effect on Shh- cells, inducing their proliferation and migration. Shh+ cells were chemo-resistant and showed features of cancer stem cells (CSCs) in vitro and in vivo. Pharmacological inhibition of the Shh pathway suppressed their CSC features. A high percentage of Shh+ cells was associated with poor prognosis in early-stage NSCLC patients. In conclusion, we describe for the first time the presence of an abnormal membrane-bound full-length Shh protein in human cancer cells that allows the identification of CSCs in vitro and in vivo.

Evaluation and Isolation of Cancer Stem Cells Using ALDH Activity Assay.

The aldehyde dehydrogenase (ALDH) is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids. In this chapter, it is described the role of ALDH in the identification of cancer stem cells (CSCs), having been shown that stem cells express high levels of ALDH. Here, we present a method called ALDEFLUOR assay used for the identification, evaluation, and isolation of normal, cancer stem and progenitor cells.

Surface Markers for the Identification of Cancer Stem Cells.

Cancer stem cells have genetic and functional characteristics that can turn them resistant to standard cancer therapeutic targets. Identification of these cells is challenging and is mostly done by detecting the expression of their antigens in a group of stem cells. Currently, there are a significant number of surface markers available which can detect the cancer stem cells by directly targeting their specific antigens present in cells. These markers possess differential expression patterns and sub-localizations in cancer stem cells when compared to non-neoplastic stem cells and somatic cells. In addition to molecular markers, multiple analytical methods and techniques including functional assays, cell sorting, filtration approaches, and xenotransplantation methods are used to identify cancer stem cells. This chapter will overview the functional significance of cancer stem cells, its biological correlations, specific markers, and detection methods.

ID:3004 Lung cancer stem cell and its therapeutic potential

Cancer stem cells (CSCs), a subpopulation of cancer cells with the ability to self-renew and giving rise to differentiated cancer cells, are thought to play a crucial role in tumour development, invasion, metastasis and recurrence. Treatments for lung cancer remain a challenging due to ineffectiveness of current available therapies to eradicate the quiescent and therapy-resistance of CSCs. Therefore, new treatment regime specifically targeting CSCs are needed to improve the effectiveness of lung cancer treatment. However the identification of lung CSCs especially in non-small cell lung cancer (NSCLC) remains challenging due to highly heterogeneous cell population and no standard markers to distinguish the lung CSCs from their cancer origins. The use of cell surface markers in isolation, identification and characterization of CSCs is one of the important tools as to understand the basic molecular composition and properties of CSCs and the pathways that of these heterogeneous population of cells are involved for future targeted therapy. Our group has identified, isolated and characterized putative lung CSCs from NSCLC cell line based on expression of combination CSCs markers, the CD166/CD44 and CD166/EpCAM using fluorescence activated cell sorting (FACS). The putative lung CSCs, the CD166+CD44+ CD166+EpCAM+ were characterized for multipotent and self-renewal capability using differentiation, clonogenic and spheroid assays. Following microarray gene expression study and bioinformatics analysis, our data has shown that the NF-κB was consistently expressed and shown to play a significant role in maintaining tumorigenicity of CSCs. In order to proof the role of NF-κB, the cells were treated with different concentrations of BMS-345541 (an inhibitor of NF-κB molecule) and the effectiveness of the treatments were evaluated through its ability to reduce self-renewal, expression of stemness genes (Sox2, Oct4, Klf4, Nanog and Sca-1), migration and epithelial to mesenchymal transition process (EMT) activities. The effectiveness of curcumin as drug sensitizer for effective therapy in treating chemoresistance of CSCs, was also investigated. The capability of CD166+/CD44+ and CD166+/EpCAM+ to differentiate into multipotent cell lineages (adipocytes and osteocyte), to form colony and to anchorage independent spheres and expressed stemness genes were shown in this study. The inhibition of NF-κB molecule using BMS-345441 has reduced the sphere forming capability, expression of stemness genes (Sox2, Nanog and Oct4), migration and expression of EMT genes in lung CSCs. Meanwhile, curcumin was found to reduce the cells proliferation activity and induced apoptosis of the cells. In addition, curcumin was also able to sensitize cisplatin, to supress the migration ability and inhibiting self-renewal capability of lung CSCs. Besides, the mRNA level of Sox2, Klf4, Nanog and Oct4 were down-regulated in lung CSCs after treatment with combination of both curcumin and cisplatin. Our findings suggest that NF-κB could be used as a potential targeted gene for lung cancer gene modification whereas curcumin could be used as potential natural compound that was able to sensitize the chemotherapy drug for effective cancer therapy.

Diagnostic and prognostic value of cancer stem cell marker CD44 and soluble CD44 in the peripheral Blood of patients with oral Squamous cell carcinoma

BackgroundHead and neck cancer is a major health problem. Recent studies on the pathobiology of oral squamous cell carcinoma (OSCC) have led to the discovery of a small population of cancer cells with a consistent behavior with the features of cancer stem cells (CSCs). CSCs are required and responsible for initiation, maintenance and recurrence of disease. Molecular markers are commonly used for the identification of CSCs. CD44 is the most reported CSC marker in OSCC.The aim of the study was to evaluate and correlate the expression of CD44 in different histopathological grades of OSCC, as well as to assess the diagnostic and prognostic value of soluble CD44 (CD44sol) in peripheral blood of patients.Materials and methodsFifteen patients with OSCC were included; biopsies were histologically evaluated using haematoxylin and eosin. Serial sections were immunohistochemically stained by monoclonal antibody to CD44. The intensity of immunostaining of CD44 was calculated. Enzyme-linked immunosorbent assay (ELISA) method was used to determine the concentration of CD44sol in the blood serum.ResultsAll grades of OSCC showed membranous immunosignaling of CD44. The well, moderately and poorly differentiated OSCC cases showed weak, moderate and intense positive membranous immunosignaling of CD44 respectively.CD44sol levels were significantly higher in OSCC patients than they were in control groups. Soluble CD44 serum levels were significantly higher in poorly differentiated than they were in moderately and well differentiated.ConclusionCSCs detection in fixed human tissue and CD44sol detection in peripheral blood using ELISA seemed to be a promising method and may have a diagnostic and prognostic value in management of OSCC.

Flt-1-positive cells are cancer-stem like cells in colorectal carcinoma.

Recent evidence demonstrates an essential role of cancer stem cells (CSCs) in cancer initiation, progression, migration, metastasis as well as chemo-resistance. Nevertheless, identification of CSCs in different cancers has not been succeeded, since such CSCs are typically lack of a specific and unique marker. Therefore, the current strategy is basically using one or several markers to enrich CSCs, or to isolate CSC-like cells. Here, we showed that in clinically obtained colorectal carcinoma (CRC) specimens, Flt-1, the type 1 receptor for vascular endothelial growth factor A, was significantly upregulated. Moreover, more distal metastasis and poorer patient survival were detected in Flt-1high CRC, compared to Flt1low subjects. Two CRC cell lines were then labeled with both luciferase and red fluorescent protein (RFP) reporters. We found that in both lines, compared to Flt-1- CRC cells, Flt-1+ CRC cells generated significantly more tumor spheres in culture, appeared to be more resistant to fluorouracil-induced apoptosis, were more detectable in the circulation after subcutaneous transplantation, and had a higher chances to generate tumor after serial adoptive transplantation. Thus, we conclude that Flt-1 may be used as a surface marker to enrich CSC in CRC. Selective elimination of Flt-1+ CRC cells may improve the therapeutic outcome.

Abstract 745: Interleukin-13 conjugated quantum dots to identify glioma initiating cells and exosomes

Abstract High grade brain tumors like glioblastoma multiforme (GBM) and certain other brain metastatic cancers possess high tumor invasive and infiltrating properties making them harder to detect. Identification of cancer stem cells and exosomes secreted by them in the biofluids like cerebrospinal fluid (CSF) will be an ideal way of detecting the presence of residual cancer after therapy. In the current approach, a ligand conjugated quantum dot (QD) was utilized to specifically label the cancer stem cells and exosomes to identify the presence of IL13Rα2 a tumor invasive marker. Human glioma initiating cells were cultured in adherent form and were exposed to interleukin-13 conjugated quantum dots (IL13QD), which binds the glioma initiating cells expressing IL13Rα2 receptor. Similarly the exosomes isolated from cancer stem cell condition media and CSF was briefly incubated with IL13QD, before analyzing their complexing pattern. Exosomes that were isolated from glioma stem cells and patients CSF were demonstrated to express IL13Rα2 receptor. Fluorescent microscopy, transmission electron microscopy and flow cytometry were performed on the exosomes after complexing with IL13QD. IL13QD was demonstrated to specifically bind glioma stem cells both in the monolayer and spheroid culture. The binding affinity of the exosomes to the quantum dots were quantitatively and qualitatively confirmed by atomic force microscopy (AFM). The morphology and size of exosomes before and after complexing with exosomes were confirmed by electron microscopy and AFM. The density plot from the flow cytometry experiments with IL13QD-exosomes complex indicates a possibility to identify the tumor associated exosomes. Our experiment infers that tumor targeted quantum dots can selectively bind with glioma stem cells and extracellular vesicles (exosomes) that are secreted by cancer cells. This binding profile could be utilized to identify the expression of certain tumor promoting receptors and antigens on the surface of exosomes present in the CSF and cancer stem cells from the glioma patients. Experiments are in progress to identify the tumor initiating cells in an orthotopic mouse glioma tumor model after intravenous administration of wild type IL13 and certain high affinity mutated IL13 conjugated quantum dots, by non-invasive way. Citation Format: Achuthamangalam B. Madhankumar, Oliver Mrowczynski, Brad Zacharia, Michael Glantz, Lichong Xu, Becky Webb, Christopher Siedlecki, Akiva Mintz, James R. Connor. Interleukin-13 conjugated quantum dots to identify glioma initiating cells and exosomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 745. doi:10.1158/1538-7445.AM2017-745

Harnessing the DNA Dye-triggered Side Population Phenotype to Detect and Purify Cancer Stem Cells from Biological Samples.

Cancer is a stem cell-driven disease and eradication of these cells has become a major therapeutic goal. Deciphering vulnerabilities of Cancer Stem Cells (CSCs) and identifying suitable molecular targets relies on methods that allow their specific discrimination in heterogeneous samples such as cell lines and ex vivo tumor tissue. Flow cytometry/FACS is a powerful technology to multi-parametrically dissect biological samples at the single cell level and is to date the method of choice to recover live cells for downstream analyses. Surface markers such as CD44 and CD133 as well as detection of aldehyde dehydrogenase enzymatic activity have often been used to define and sort out CSCs from tumor samples by FACS. A complementary approach, depicted here in methodological detail, makes use of functional dye extrusion by ABC drug transporters, which identifies a distinct population of fluorescence-dim cells commonly referred to as side population (SP). SPcancer cells exhibit canonical stem cell characteristics and can be abrogated and functionally confirmed using agents that inhibit the dye-extruding drug transporter (most frequently ABCB1/P-glycoprotein/MDR1/CD243 and ABCG2/Bcrp1/CD338). Moreover, the SPassay is compatible with other flow cytometric evaluations such as staining of surface antigens, aldehyde dehydrogenase detection and dead cell discrimination (e.g., with 7-AAD or propidium iodide (PI)). Thus, we describe a valuable and broadly applicable method for CSC identification, isolation and sub-characterization mechanistically based on a functional, rather than a phenotypic parameter. Although originally performed with Hoechst 33342 as triggering dye, we here focus on the more recent Violet dye-based SP phenotype that is resolvable on any flow cytometer equipped with a violet laser source.

DKK3 attenuates the cytotoxic effect of natural killer cells on CD133+ gastric cancer cells.

Cancer stem cell (CSCs) has started a new era in cancer research. CD133 is a widely used marker for identification of CSCs. More and more studies showed that NK cells preferentially target cancer stem-like cells. However, the deeper mechanism of the susceptibility of cancer stem cells to NK cells remains unclear. In this study, we isolated CD133 positive population of a gastric cancer cell line, BGC823 cells, and cultured with NK cells. We found that CD133 could efficiently active NK cells in an NKG2D-dependent manner. DKK3 has been demonstrated as a suppressor in many cancers. Interestingly, we found that DKK3 suppressed CD133-induced activation in NK cells by inhibiting Erk pathway and immunological synapse (IS) formation. NK cells-based CSCs immunotherapy may be a novel approach for cancer therapy.

Impact of Environmental Pollutant Cadmium on the Establishment of a Cancer Stem Cell Population in Breast and Hepatic Cancer.

Cadmium, a heavy metal pollutant, causes cancer. The existence of cancer stem cells (CSCs) in tumors is widely considered to be the reason for the recurrence and treatment failure of cancer. Increasing evidence has confirmed that under certain conditions non-CSCs could be converted into CSCs. The impact of cadmium on the development of CSC lineage in the bulk tumor cell population is not yet studied. The aim of this study was to evaluate the effect of cadmium on the conversion of non-CSCs to CSCs and the identification of CSCs based on the concurrent monitoring of multiple CSC markers. High-content monitoring of molecular markers was performed using quantum dot (QD) nanoprobes and an acousto-optical tunable filter (AOTF)-based imaging device. Cadmium treatment significantly increased the CSC population in MCF-7 and HepG2 cell lines. The cadmium-induced CSCs were identified by a concurrent analysis of stem-cell markers, namely, CD44, CD24, CD133, and ALDH1. Moreover, increased m-RNA expression of CD44, ALDH1, and CD133 and protein expression of p-Ras, p-Raf-1, p-MEK-1, and p-ERK-1 were observed in the cadmium-treated MCF-7 and HepG2 cells. This study demonstrates that cadmium induces the gene expression of CSC markers in the breast and liver cancer cell lineage and promotes the conversion of non-CSCs to CSCs.

Expression of the cancer stem cell markers ABCG2 and OCT-4 in right-sided colon cancer predicts recurrence and poor outcomes.

Right-sided colon cancer (RCC) has a poorer prognosis and a higher relapse rate than left-sided colon cancer (LCC). Like cancer stem cells (CSCs), RCC cells cannot be fully eradicated and are often involved in relapse or metastasis. Because CSCs may be linked with poor outcomes, CSC markers may have prognostic value in RCC. ATP-binding cassette sub-family G member 2 (ABCG2) and OCT-4 (also known as POU5F1) are among the most useful markers for CSC identification. We therefore examined the malignant behavior of ABCG2 and OCT-4 in vitro and in vivo, and their expression was assessed in pathology tissues obtained from clinicopathologically recurrent and non-recurrent cases. Our survey suggested associations between ABCG2 and OCT-4 expression and RCC clinicopathological variables. No correlations were detected between ABCG2 or OCT-4 expression and age, gender, tumor size, or tumor shape, but ABCG2 expression correlated with TNM stage, tumor differentiation, and lymphovascular invasion. Additionally, expression of both ABCG2 and OCT-4 correlated with RCC recurrence and poor outcomes.

Cancer stem cell molecular markers verified in vivo

This systematic review was aimed at identification of cancer stem cells (CSC) molecular markers, which was validated in experiments on transplantation of tumor subpopulations with different phenotypes to immunodeficient animals. After careful examination of available papers, we selected 97 reports, fully consistent with the objectives of the study. The results of their analysis show that markers commonly used for CSC isolation include: CD133, СD44, ALDH, CD34, CD24, and EpCAM. The review also contains description of molecular features of some CSC markers; it also considers modern approaches to cancer treatment by targeting this population and evaluates perspectives of further development of the CSC theory.