Cancer Stem Cell Reprogramming Research Articles

STEM-22. TARGETING PYRIMIDINE SYNTHESIS ACCENTUATES MOLECULAR THERAPY RESPONSE IN GLIOBLASTOMA STEM CELLS

Abstract Glioblastoma stem cells (GSCs) reprogram glucose metabolism by hijacking high-affinity glucose uptake to survive in a nutritionally dynamic microenvironment. Here, we trace metabolic aberrations in GSCs to link core genetic mutations in glioblastoma to dependency on de novo pyrimidine synthesis. Targeting the pyrimidine synthetic rate-limiting step enzyme carbamoyl-phosphate synthetase 2, aspartate transcarbamyolase, dihydroorotase (CAD) or the critical downstream enzyme, dihydroorotate dehydrogenase (DHODH) inhibited GSC survival, self-renewal, and in vivo tumor initiation through the depletion of the pyrimidine nucleotide supply in rodent models. Mutations in EGFR or PTEN generated distinct CAD phosphorylation patterns to activate carbon influx through pyrimidine synthesis. Simultaneous abrogation of tumor-specific driver mutations and DHODH activity with clinically approved inhibitors demonstrated sustained inhibition of metabolic activity of pyrimidine synthesis and GSC tumorigenic capacity. Higher expression of pyrimidine synthesis genes portend poor prognosis of glioblastoma patients. Collectively, our results demonstrate a therapeutic approach of precision medicine through targeting the nexus between driver mutations and metabolic reprogramming in cancer stem cells.

Absence of an embryonic stem cell DNA methylation signature in human cancer

BackgroundDifferentiated cells that arise from stem cells in early development contain DNA methylation features that provide a memory trace of their fetal cell origin (FCO). The FCO signature was developed to estimate the proportion of cells in a mixture of cell types that are of fetal origin and are reminiscent of embryonic stem cell lineage. Here we implemented the FCO signature estimation method to compare the fraction of cells with the FCO signature in tumor tissues and their corresponding nontumor normal tissues.MethodsWe applied our FCO algorithm to discovery data sets obtained from The Cancer Genome Atlas (TCGA) and replication data sets obtained from the Gene Expression Omnibus (GEO) data repository. Wilcoxon rank sum tests, linear regression models with adjustments for potential confounders and non-parametric randomization-based tests were used to test the association of FCO proportion between tumor tissues and nontumor normal tissues. P-values of < 0.05 were considered statistically significant.ResultsAcross 20 different tumor types we observed a consistently lower FCO signature in tumor tissues compared with nontumor normal tissues, with 18 observed to have significantly lower FCO fractions in tumor tissue (total n = 6,795 tumor, n = 922 nontumor, P < 0.05). We replicated our findings in 15 tumor types using data from independent subjects in 15 publicly available data sets (total n = 740 tumor, n = 424 nontumor, P < 0.05).ConclusionsThe results suggest that cancer development itself is substantially devoid of recapitulation of normal embryologic processes. Our results emphasize the distinction between DNA methylation in normal tightly regulated stem cell driven differentiation and cancer stem cell reprogramming that involves altered methylation in the service of great cell heterogeneity and plasticity.

Reprogramming of cancer stem cells into non-tumorigenic cells using stem cell exosomes for cancer therapy

Cancer stem cells (CSCs) are a small population of cells with stem cell-like properties found in tumors. CSCs are closely associated with tumor heterogeneity, which influences tumor progress, metastasis, and drug resistance. Here, we propose a concept to enhance efficacy of cancer therapy through CSC reprogramming into non-tumorigenic cells using stem cell-derived exosomes with osteoinductive potential. We hypothesized that exosomes derived from osteogenic differentiating human adipose-derived stem cells (OD-EXOs) contain specific cargos capable of inducing osteogenic differentiation of CSCs. Quantitative RT-PCR analysis revealed that OD-EXOs enhanced the expression of osteogenic-related genes, such as alkaline phosphatase (ALPL), osteocalcin (BGLAP), and runt-related transcription factor 2 (RUNX2). In addition, expression of drug-resistance genes such as ATP binding cassette (ABC) transporter, the breast cancer gene family (BCRA1 and BCRA2), and the ErbB gene family were significantly decreased in OD-EXO-treated CSCs. Our findings suggest that OD-EXOs function as a biochemical cue for CSC reprogramming and contribute to overcoming therapeutic resistance.

The role of bone morphogenetic protein 2 in the reprogramming of cancer stem cells

Bone morphogenetic protein 2 (BMP-2) is a family member of the transforming growth factor-beta (TGF-?) superfamily and firstly recognized in early embryonic and postnatal development. BMP-2 has been reported to have crucial role in bone and cartilage formation, tissues and organs development, regulate cell differentiation, proliferation, angiogenesis, morphogenesis, chemotaxis, cellular survival and apoptosis. The BMPs are also identified as factors in tumor development and propagation; distinctly associated to diverse sides of carcinogenesis. The theory of cancer stem cells (CSCs) hypothesized that only a small hierarchical organization of cells is assisting tumorigenesis and inheriting cellular heterogeneity throughout long-life primary tumor. Reprogramming of CSCs using induced pluripotent stem cell (iPSC) approach possibly benefits in identifying the CSCs-related oncogenes, tumor-suppressor genes, and interactions between CSCs-related genes and the cancer microenvironment. Moreover, the reprogramming technology may provide crucial information related to cancer initiation and progression. This review will be focusing on BMP-2 signaling in modulating normal cells, human diseases, and cancer progression and suppression. Furthermore, this review will provide summary of updated reports on the role of BMP-2 in the developments of CSCs and its possible role as therapy through reprogramming technology by BMP-2 as an important regulatory factor in modulating the proliferation and aggressive properties of CSCs

PO-292 Breast cancer stem cell reprogramming: deciphering the impact of glucose and the contribute of tumour microenvironment

IntroductionDiabetes-associated hyperglycemia is linked to poorer prognosis and survival in breast cancer (BC). Indeed, glucose can affect both tumour and tumour-surrounding cells. BC cells are embedded in an adipocyte-rich microenvironment, which, beside adipocytes, contains Stromal-Vascular Fraction Cells (SVFCs). In this scenario, epithelial and stromal compartments communicate through the release of soluble factors and establish an intricate crosstalk. Here, we analysed whether glucose could directly affect the phenotype of ER+ MCF7 BC cells and interfere with their interaction with adipose-derived SVFCs, thereby promoting tumour progression.Material and methodsMCF7 cell stemness markers were measured by qReal-Time PCR. Adipose-derived (Ad-)SVFCs were obtained by mammary adipose tissue specimens of women undergoing plastic surgery. The trascriptome of MCF7 exposed to either low (LG-5.5 mM) or high glucose concentration (HG-25 mM) was obtained by RNA-Sequencing (Illumina HiSeq3000).Results and discussionsHG exposure of MCF7 determined a significant increase of SOX2 mRNA levels as compared to LG, suggesting the induction of stemness programming. Co-culture with Ad-SVFCs in HG increased SOX2, NANOG and OCT4 mRNA levels in MCF7, as compared to isolated culture, indicating the involvement of SVF-produced soluble factors in BC stem cell reprogramming. Moreover, in presence of Ad-SVFCs and HG, MCF7 produced a higher number of mammospheres, which also displayed larger size. However, both in LG and in HG, conditioned media (CM) obtained from Ad-SVFCs produced no relevant effect on MCF7 stemness. Nevertheless, when Ad-SVFCs were pre-incubated with CM obtained from HG-treated MCF7, their CM very effectively increased OCT4, NANOG and SOX2 mRNA levels in MCF7. Thus, HG likely perturbs MCF7, which produce soluble factors leading Ad-SVFCs to release, in turn, reprogramming factors for BC cell stemness. In this regard, we have observed that HG modification of MCF7 transcriptome includes deregulation of 17 genes (pval=0.05) encoding for secreted proteins involved in cancer progression-related pathways, which may potentially play a role in tumour-stroma interactions.ConclusionGlucose affects BC stem cell reprogramming both directly and through Ad-SVFCs. Deciphering the mechanisms that govern this intricate crosstalk will pave the way to new targeted strategies to improve BC control in conditions of metabolic derangement.

Cytokeratin 19 (KRT19) has a Role in the Reprogramming of Cancer Stem Cell-Like Cells to Less Aggressive and More Drug-Sensitive Cells.

Cytokeratin 19 (KRT19) is a cytoplasmic intermediate filament protein, which is responsible for structural rigidity and multipurpose scaffolds. In several cancers, KRT19 is overexpressed and may play a crucial role in tumorigenic transformation. In our previous study, we revealed the role of KRT19 as signaling component which mediated Wnt/NOTCH crosstalk through NUMB transcription in breast cancer. Here, we investigated the function of KRT19 in cancer reprogramming and drug resistance in breast cancer cells. We found that expression of KRT19 was attenuated in several patients-derived breast cancer tissues and patients with a low expression of KRT19 were significantly correlated with poor prognosis in breast cancer patients. Consistently, highly aggressive and drug-resistant breast cancer patient-derived cancer stem cell-like cells (konkuk university-cancer stem cell-like cell (KU-CSLCs)) displayed higher expression of cancer stem cell (CSC) markers, including ALDH1, CXCR4, and CD133, but a much lower expression of KRT19 than that is seen in highly aggressive triple negative breast cancer MDA-MB231 cells. Moreover, we revealed that the knockdown of KRT19 in MDA-MB231 cells led to an enhancement of cancer properties, such as cell proliferation, sphere formation, migration, and drug resistance, while the overexpression of KRT19 in KU-CSLCs resulted in the significant attenuation of cancer properties. KRT19 regulated cancer stem cell reprogramming by modulating the expression of cancer stem cell markers (ALDH1, CXCR4, and CD133), as well as the phosphorylation of Src and GSK3β (Tyr216). Therefore, our data may imply that the modulation of KRT19 expression could be involved in cancer stem cell reprogramming and drug sensitivity, which might have clinical implications for cancer or cancer stem cell treatment.

Abstract 66: c-Fos: A new player in promotion of cancer stem-like cell properties in head and neck squamous cell carcinoma

Abstract Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. We have shown that c-Fos was highly up-regulated in the HNSCC sphere forming cells. However, upregulation of c-Fos for the biology of HNSCC-CSCs remains unknown. In this study, we investigated the role of c-Fos in renewal of stemness of HNSCC and tumor growth. We demonstrated that c-Fos overexpression enhanced the epithelial-mesenchymal transition (EMT) state and expression of CSC markers (Nanog, c-Myc, Sox2 and Notch1). Ectopic expression of c-Fos in HNSCC cells also display increased number of sphere formation. We further observed that overexpression of c-Fos increased the expression of pERK and cyclin D1 in HNSCC cells. Knockdown of c-Fos in Cal27 cells impaired sphere formation. Next we examine the effect of c-Fos expression in vivo. For this, we established stable HNSCC cell line (MDA1386Tu cells) where c-Fos gene is ectopically expressed. Our results demonstrated that exogenous expression of c-Fos in non-tumorigenic MDA1386Tu cells makes these cells tumorigenic in nude mice. Further, subcutaneous transplantation of c-Fos overexpressing Cal27 cells (tumorigenic) into immunocompromised mice enhanced tumor growth as compared to parental cells. Taken together, our results strongly demonstrated a novel role of c-Fos as a regulator of EMT and cancer stem cell reprogramming in HNSCC cells. Collectively, our results offer that c-Fos may be a new target for developing therapeutic strategies against HNSCC. Citation Format: Ratna B. Ray. c-Fos: A new player in promotion of cancer stem-like cell properties in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 66.

Glycolysis gatekeeper PDK1 reprograms breast cancer stem cells under hypoxia

Glycolysis is critical for cancer stem cell reprogramming; however, the underlying regulatory mechanisms remain elusive. Here, we show that pyruvate dehydrogenase kinase 1 (PDK1) is enriched in breast cancer stem cells (BCSCs), whereas depletion of PDK1 remarkably diminishes ALDH+ subpopulations, decreases stemness-related transcriptional factor expression, and inhibits sphere-formation ability and tumor growth. Conversely, high levels of PDK1 enhance BCSC properties and are correlated with poor overall survival. In mouse xenograft tumor, PDK1 is accumulated in hypoxic regions and activates glycolysis to promote stem-like traits. Moreover, through screening hypoxia-related long non-coding RNAs (lncRNAs) in PDK1-positive tissue, we find that lncRNA H19 is responsible for glycolysis and BCSC maintenance. Furthermore, H19 knockdown decreases PDK1 expression in hypoxia, and ablation of PDK1 counteracts H19-mediated glycolysis and self-renewal ability in vitro and in vivo. Accordingly, H19 and PDK1 expression exhibits strong correlations in primary breast carcinomas. H19 acting as a competitive endogenous RNA sequesters miRNA let-7 to release Hypoxia-inducible factor 1α, leading to an increase in PDK1 expression. Lastly, aspirin markedly attenuates glycolysis and cancer stem-like characteristics by suppressing both H19 and PDK1. Thus, these novel findings demonstrate that the glycolysis gatekeeper PDK1 has a critical role in BCSC reprogramming and provides a potential therapeutic strategy for breast malignancy.

Abstract 5761: C-Fos drives non-tumorigenic head and neck squamous cell carcinoma cells to tumorigenic by promoting cancer stem cells like properties

Abstract Purposes of the study: Head and neck squamous cell carcinoma (HNSCC) is the sixth most widespread cancer and leading cause of cancer related death world widely. Regardless of the advancement in treatment processes the overall survival rate of patients having this cancer has not substantially improved in the past few decades. Development of tumor and its progression exclusively resides in a small population of cancer cells, termed as cancer stem cells (CSCs). This population of cells can self-renew and re-form the ordered organization of tumors. CSCs contribute to HNSCC and may offer prominent therapeutic strategy for the management of HNSCC. We previously observed that c-Fos was highly up-regulated in the HNSCC sphere forming cells. In the present study, we explored the role of c-Fos in the tumor initiation in relation with cancer stemness and EMT. Experimental procedures: We examined whether overexpression of c-Fos has an effect on tumorigenicity and stemness. For this, c-Fos was overexpressed in non-tumorigenic HNSCC cell lines and tumor growth was investigated. We also examined the expression of different CSC marker genes expression by Western blot analysis. Summary: Our results demonstrated that exogenous expression of c-Fos in non-tumorigenic MDA1386Tu cells makes the cells tumorigenic in nude mice. Mechanistic investigations showed that c-Fos overexpression in MDA1386Tu cells enhanced epithelial-mesenchymal transition (EMT)/CSC properties and increased numbers of oralspheres when grown in ultra-low binding plate. Conclusions: Collectively, our data strongly demonstrate that c-Fos plays a critical role in the modulation of EMT and cancer stem cell reprogramming in HNSCC cells and enhance tumor growth. Note: This abstract was not presented at the meeting. Citation Format: Naoshad Muhammad, Sourav Bhattacharya, Robert Steele, Nancy Phillips, Ratna B. Ray. C-Fos drives non-tumorigenic head and neck squamous cell carcinoma cells to tumorigenic by promoting cancer stem cells like properties [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 5761. doi:10.1158/1538-7445.AM2017-5761

Involvement of c-Fos in the Promotion of Cancer Stem-like Cell Properties in Head and Neck Squamous Cell Carcinoma.

Purpose: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Although improvements in surgical techniques, chemotherapy and radiation delivery, and supportive care have improved quality of life for patients with HNSCC, regional and distant recurrence remain common. Recent evidence suggests that cancer stem-like cells (CSC) play a significant role in recurrence and chemoresistance. We previously observed that c-Fos was highly upregulated in the HNSCC sphere-forming cells. Consequences of c-Fos upregulation for the biology of HNSCC-CSCs are poorly understood. In this study, we investigated the role of c-Fos in renewal of stemness of HNSCC and tumor growth.Experimental Design and Results: We generated stable HNSCC cell lines ectopically expressing the c-Fos gene. Exogenous expression of c-Fos in nontumorigenic MDA1386Tu cells makes these cells tumorigenic in nude mice. Furthermore, subcutaneous transplantation of c-Fos-overexpressing Cal27 cells (tumorigenic) into immunocompromised mice enhanced tumor growth as compared with parental cells. Mechanistic investigations demonstrated that c-Fos overexpression enhanced the epithelial-mesenchymal transition (EMT) state and expression of CSC markers (Nanog, c-Myc, Sox2, and Notch1). Ectopic expression of c-Fos in HNSCC cells also displays increased sphere formation. We further observed that overexpression of c-Fos increased the expression of pERK and cyclin D1 in HNSCC cells.Conclusions: Together, our results strongly suggest a novel role of c-Fos as a regulator of EMT and cancer stem cell reprogramming in HNSCC cells, which may hold potential as a CSC-directed therapeutic approach to improve HNSCC treatment. Clin Cancer Res; 23(12); 3120-8. ©2016 AACR.

Cancer stem cell heterogeneity: origin and new perspectives on CSC targeting.

Most of the cancers are still incurable human diseases. According to recent findings, especially targeting cancer stem cells (CSCs) is the most promising therapeutic strategy. CSCs take charge of a cancer hierarchy, harboring stem cell-like properties involving self-renewal and aberrant differentiation potential. Most of all, the presence of CSCs is closely associated with tumorigenesis and therapeutic resistance. Despite the numerous efforts to target CSCs, current anti-cancer therapies are still impeded by CSC-derived cancer malignancies; increased metastases, tumor recurrence, and even acquired resistance against the anti-CSC therapies developed in experimental models. One of the most forceful underlying reasons is a “cancer heterogeneity” due to “CSC plasticity” A comprehensive understanding of CSC-derived heterogeneity will provide novel insights into the establishment of efficient targeting strategies to eliminate CSCs. Here, we introduce findings on mechanisms of CSC reprogramming and CSC plasticity, which give rise to phenotypically varied CSCs. Also, we suggest concepts to improve CSC-targeted therapy in order to overcome therapeutic resistance caused by CSC plasticity and heterogeneity.

Getting to the heart of the matter in cancer: Novel approaches to targeting cancer stem cells.

Cancer is one of the leading causes of deaths worldwide. While cancers may initially show good response to chemotherapy or radiotherapy, it is not uncommon for them to recur at a later date. This phenomenon may be explained by the existence of a small population of cancer stem cells, which are inherently resistant to anti-cancer treatment as well as being capable of self-renewal. Therefore, while most of the tumour bulk consisting of cells that are not cancer stem cells respond to treatment, the cancer stem cells remain, leading to disease recurrence. Following this logic, the effective targeting of cancer stem cells holds promise for providing long-term cure in individuals with cancer. Cancer stem cells, like normal stem cells are endowed with mechanisms to protect themselves against a wide range of insults including anti-cancer treatments, such as the enhancement of the DNA damage response and the ability to extrude drugs. It is therefore important to develop new strategies if cancer stem cells are to be eradicated. In this review, we describe the strategies that we have developed to target cancer stem cells. These strategies include the targeting of the histone demethylase jumonji, AT rich interactive domain 1B (JARID1B), which we found to be functionally significant in the maintenance of cancer stem cells. Other strategies being pursued include reprogramming of cancer stem cells and the targeting of a functional cell surface marker of liver cancer stem cells, the aminopeptidase CD13.

P3.01-062 Profiling DNA Methylation and Gene Expression on Cancer Stemness Reprogramming in Lung Adenocarcinoma: Topic: Stem Cells in Lung Cancer

The cancer stemness niche that could promote and induce the reprogramming of cancer stem cells (CSCs), is considered as one of the key factors in cancer metastasis, tumor recurrence and drug resistance. The behavior of this specific tumorous microenvironment may correlate with poor prognosis of the disease. However, the contribution of the cancer stemness niche on regulating the differentiation or de-differentiation of CSCs remains unclear. To investigate the mystery of the niche and to discover the genetic and epigenetic machineries along the reprogramming process; here, using the lung CSC/stromal cells co-culture model, integrating with both genome-wide transcriptome and DNA methylome, the gene expression and DNA methylation patterns were analyzed in lung CSCs and the differentiated clones. We found that the stromal cells-incubated lung CSCs (StriCLS1) were significantly characterized as the CSC enriched population; with highly expressed stemness makers, nanog, oct3/4, sox2, and klf4, and showed relatively higher percentages of side population, ALDH activity and tumorigeniety than differentiated cells in both in vitro tumor sphere forming ability and in vivo xenograft model (only 10 StriCLS1 cells could generate tumor formation in NSG mice). We found that these stemness characteristics diminished as removing the feeder stroma cells and could be restored after re-co-culture with the tumorous stroma cells. Although the whole exon-seq data showed the comparability of StriCLS1 and differentiated CLS1 CSCs on the DNA sequences; the gene expression and DNA methylation patterns revealed significantly changes. The results showed that stemness and its reprogramming were related to paracrine/autocrine networks (IGFBPs, WNTs/Hedgehog, HGF/Met, LIF/LIFR), metabolism shift (PDKs and LDHs), and other drug-resistance or stress-response signaling (ABCG2 and AKTs), indicating that these key factors were regulated via the niche which may be affected by the DNA methylation patterning. We conclude that the cancer stemness reprogramming is a well-regulatory process via the paracrine/autocrine connective networks in the tumor microenvironment. This process may contribute to cancer progression, and assist the tumor growth and evolution under different stresses. This study provides new insight into the importance of crosstalk between CSCs and the cancerous microenvironment that could be targeted as potential genetic/epigenetic signaling regulators for anticancer therapy.

Nuclear reprogramming of cancer stem cells: Corrupting the epigenetic code of cell identity with oncometabolites

ABSTRACTGeneration of cancer stem cell (CSC)-like cells might occur through metabolic corruption of the epigenetic codes that govern cell identity. We recently identified how archetypal oncometabolites, without altering the baseline expression of endogenous stem cell maintenance genes but endowing cells with epigenetic states refractory to differentiation, considerably enhance the global kinetic efficiency of nuclear reprogramming processes that generate CSC-like states de novo. This study highlights that metabolo-epigenetic axes of communication can direct the development and maintenance of CSCs during the natural history of cancer diseases.

A new insight into cancer stem cell markers: Could local and circulating cancer stem cell markers correlate in colorectal cancer?

Cancer stem cell (CSC) markers could serve as potential prognostic procedure. This study is aimed to investigate the local expression of doublecortin-like kinase 1 (DCLK1) and Lgr5 in colorectal cancer tissues (CRC) at both protein and messenger RNA (mRNA) level, followed by providing a comparison of the local and circulating expression pattern of these markers, based on our present and previous study. The mRNA expression level of DCLK1 and Lgr5 was evaluated using comparative real-time PCR method applying 58 fresh tumor tissues and their correspondent normal margins. Immunohistochemistry was applied to analyze the protein expression level of DCLK1 and Lgr5 in paraffin-embedded CRC tissues. The correlation of DCLK1 and Lgr5 expression pattern with clinicopathological characteristics was assessed. A higher mRNA expression level of DCLK1 (3.28-fold change, p < 0.001) and Lgr5 (2.29-fold change, p < 0.001) was observed in CRC fresh tissues compared to the normal adjacent margins, and the expression level was higher in patients with higher grade and stages of disease and patients who underwent neoadjuvant chemoradiotherapy (CRT). The protein expression level of DCLK1 and Lgr5 was also increased significantly in tumor tissues compared to normal colon tissues which were positively correlated to tumor stage and grade and neoadjuvant CRT. Taken together, the results of protein analysis were in accordance with mRNA assessment. The local expression pattern of DCLK1 and Lgr5 was also in accordance with their expression level in circulation. However, some minor inconsistencies were observed which may be attributed to several factors including the possible effect of CRT on CSC reprogramming.

In vivo epigenetic reprogramming of primary human colon cancer cells enhances metastases.

How metastases develop is not well understood and no genetic mutations have been reported as specific metastatic drivers. Here we have addressed the idea that epigenetic reprogramming by GLI-regulated pluripotent stemness factors promotes metastases. Using primary human colon cancer cells engrafted in mice, we find that transient expression of OCT4, SOX2, KLF4 +/− cMYC establishes an enhanced pro-metastatic state in the primary tumor that is stable through sequential engraftments and is transmitted through clonogenic cancer stem cells. Metastatic reprogramming alters NANOG methylation and stably boosts NANOG and NANOGP8 expression. Metastases and reprogrammed EMT-like phenotypes require endogenous NANOG, but enhanced NANOG is not sufficient to induce these phenotypes. Finally, reprogrammed tumors enhance GLI2, and we show that GLI2high and AXIN2low, which are markers of the metastatic transition of colon cancers, are prognostic of poor disease outcome in patients. We propose that metastases arise through epigenetic reprogramming of cancer stem cells within primary tumors.

An RNA editing fingerprint of cancer stem cell reprogramming.

BackgroundDeregulation of RNA editing by adenosine deaminases acting on dsRNA (ADARs) has been implicated in the progression of diverse human cancers including hematopoietic malignancies such as chronic myeloid leukemia (CML). Inflammation-associated activation of ADAR1 occurs in leukemia stem cells specifically in the advanced, often drug-resistant stage of CML known as blast crisis. However, detection of cancer stem cell-associated RNA editing by RNA sequencing in these rare cell populations can be technically challenging, costly and requires PCR validation. The objectives of this study were to validate RNA editing of a subset of cancer stem cell-associated transcripts, and to develop a quantitative RNA editing fingerprint assay for rapid detection of aberrant RNA editing in human malignancies.MethodsTo facilitate quantification of cancer stem cell-associated RNA editing in exons and intronic or 3'UTR primate-specific Alu sequences using a sensitive, cost-effective method, we established an in vitro RNA editing model and developed a sensitive RNA editing fingerprint assay that employs a site-specific quantitative PCR (RESSq-PCR) strategy. This assay was validated in a stably-transduced human leukemia cell line, lentiviral-ADAR1 transduced primary hematopoietic stem and progenitor cells, and in primary human chronic myeloid leukemia stem cells.ResultsIn lentiviral ADAR1-expressing cells, increased RNA editing of MDM2, APOBEC3D, GLI1 and AZIN1 transcripts was detected by RESSq-PCR with improved sensitivity over sequencing chromatogram analysis. This method accurately detected cancer stem cell-associated RNA editing in primary chronic myeloid leukemia samples, establishing a cancer stem cell-specific RNA editing fingerprint of leukemic transformation that will support clinical development of novel diagnostic tools to predict and prevent cancer progression.ConclusionsRNA editing quantification enables rapid detection of malignant progenitors signifying cancer progression and therapeutic resistance, and will aid future RNA editing inhibitor development efforts.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-014-0370-3) contains supplementary material, which is available to authorized users.

Resveratrol Impedes the Stemness, Epithelial-Mesenchymal Transition, and Metabolic Reprogramming of Cancer Stem Cells in Nasopharyngeal Carcinoma through p53 Activation

Cancer stem cells (CSCs) are able to self-renew and are refractory to cancer treatment. To investigate the effects of resveratrol on CSCs of nasopharyngeal carcinoma (NPC), we employed a behavior selection strategy to isolate CSCs based on radioresistance, chemoresistance, and tumor sphere formation ability. These NPC CSCs displayed stem cell properties and underwent metabolic shift to predominately rely on glycolysis for energy supply. Intriguingly, we found that resveratrol turned off the metabolic switch, increased the reactive oxygen species (ROS) level, and depolarized mitochondrial membranes. These alterations in metabolism occurred concomitantly with the suppression of CSC properties including resistance to therapy, self-renewal capacity, tumor initiation capacity, and metastatic potential in NPC CSCs. We found that resveratrol impeded CSC properties through the activation of p53 and this effect could be reversed by knockdown of p53. Furthermore, resveratrol suppressed the stemness and EMT through reactivating p53 and inducing miR-145 and miR-200c, which were downregulated in NPC CSCs. In conclusion, we demonstrated that resveratrol employed the p53 pathway in regulating stemness, EMT, and metabolic reprogramming. Further investigation of the molecular mechanism of p53 activation by resveratrol may provide useful information for the development of novel therapies for cancer treatment through targeting to CSCs.

Dynamic modeling of genes controlling cancer stem cell proliferation.

The growing evidence that cancer originates from stem cells (SC) holds a great promise to eliminate this disease by designing specific drug therapies for removing cancer SC. Translation of this knowledge into predictive tests for the clinic is hampered due to the lack of methods to discriminate cancer SC from non-cancer SC. Here, we address this issue by describing a conceptual strategy for identifying the genetic origins of cancer SC. The strategy incorporates a high-dimensional group of differential equations that characterizes the proliferation, differentiation, and reprogramming of cancer SC in a dynamic cellular and molecular system. The deployment of robust mathematical models will help uncover and explain many still unknown aspects of cell behavior, tissue function, and network organization related to the formation and division of cancer SC. The statistical method developed allows biologically meaningful hypotheses about the genetic control mechanisms of carcinogenesis and metastasis to be tested in a quantitative manner.