• Humans
• Female
• Proto-Oncogene Proteins c-myc/genetics
• Proto-Oncogene Proteins c-myc/metabolism
• Prognosis
• Biomarkers, Tumor/genetics
• Biomarkers, Tumor/metabolism
• Breast Neoplasms/genetics
• Breast Neoplasms/mortality
• Breast Neoplasms/pathology
• AC133 Antigen/genetics
• Alternative Splicing
• RNA, Messenger/metabolism
• RNA, Messenger/genetics
• Gene Expression Regulation, Neoplastic
• Triple Negative Breast Neoplasms/genetics
• Triple Negative Breast Neoplasms/mortality
• Protein Isoforms
• RNA Isoforms/genetics

• decitabine
• glioblastoma
• hypomethylating agent
• immunotherapy
• temozolomide

• CD133
• Cancer
• Cancer stem cell
• Cell signaling
• Cilium
• Exosome
• Lipid raft
• Microvillus
• Prominin-1
• Stem cell

• National Institute for Cancer Research (Programme EXCELES Ministerstvo Školství, Mládeže a Tělovýchovy
• ID Project No. LX22NPO5102) Ministerstvo Školství, Mládeže a Tělovýchovy
• NU20J-07-00004 Ministerstvo Zdravotnictví Ceské Republiky
• MUNI/A/1325/2021 Masarykova Univerzita

• CD133
• Cancer stem cell
• Stemness associated markers
• Tumor microenvironment

• Phosphatidylinositol 3-Kinases/metabolism
• Signal Transduction/genetics
• Neoplastic Stem Cells/metabolism
• Cell Self Renewal

• DGAPA-UNAM IV200220 Universidad Nacional Autónoma de México
• IN229420 Universidad Nacional Autónoma de México

• CD133
• prostate cancer stem cells

Glioma‐initiating cells (GICs), a major source of glioblastoma recurrence, are characterized by the expression of neural stem cell markers and the ability to grow by forming nonadherent spheres under serum‐free conditions. Bone morphogenetic proteins (BMPs), members of the transforming growth factor‐β family, induce differentiation of GICs and suppress their tumorigenicity. However, the mechanisms underlying the BMP‐induced loss of GIC stemness have not been fully elucidated. Here, we show that paired related homeobox 1 (PRRX1) induced by BMPs decreases the CD133‐positive GIC population and inhibits tumorigenic activity of GICs in vivo. Of the two splice isoforms of PRRX1, the longer isoform, pmx‐1b, but not the shorter isoform, pmx‐1a, induces GIC differentiation. Upon BMP stimulation, pmx‐1b interacts with the DNA methyltransferase DNMT3A and induces promoter methylation of the PROM1 gene encoding CD133. Silencing DNMT3A maintains PROM1 expression and increases the CD133‐positive GIC population. Thus, pmx‐1b promotes loss of stem cell‐like properties of GICs through region‐specific epigenetic regulation of CD133 expression by recruiting DNMT3A, which is associated with decreased tumorigenicity of GICs.

• BMP
• CD133
• DNA methyltransferase
• PRRX1
• cancer-initiating cell
• glioblastoma

• Astrocytes
• GLI1
• Glioma
• Transformation
• p27(KIP1)

• Animals
• Astrocytes/metabolism
• Astrocytes/pathology
• Brain Neoplasms/genetics
• Brain Neoplasms/metabolism
• Brain Neoplasms/pathology
• Cell Line, Transformed
• Cell Line, Tumor
• Cell Proliferation
• Cell Transformation, Neoplastic/genetics
• Cell Transformation, Neoplastic/metabolism
• Cell Transformation, Neoplastic/pathology
• Cyclin-Dependent Kinase Inhibitor p27/genetics
• Cyclin-Dependent Kinase Inhibitor p27/metabolism
• Gene Expression Regulation, Neoplastic
• Glioma/genetics
• Glioma/metabolism
• Glioma/pathology
• Humans
• Mice, Inbred BALB C
• Mice, Nude
• Proto-Oncogene Proteins p21(ras)/genetics
• Proto-Oncogene Proteins p21(ras)/metabolism
• Tumor Burden
• Zinc Finger Protein GLI1/genetics
• Zinc Finger Protein GLI1/metabolism
• Mice

• ABC transporters
• cancer stem cells
• clinical trials
• drug resistance
• epithelial to mesenchymal transition
• hypoxia
• metastasis
• tumor microenvironment

• ATP-Binding Cassette Transporters/metabolism
• Cell Differentiation/drug effects
• Drug Resistance, Neoplasm
• Epithelial-Mesenchymal Transition
• Humans
• Immunotherapy/methods
• MicroRNAs/therapeutic use
• Molecular Targeted Therapy/methods
• Neoplasms/metabolism
• Neoplasms/therapy
• Neoplastic Stem Cells/metabolism
• Signal Transduction/drug effects
• Tumor Microenvironment

Glioblastoma (GBM) is a malignant brain tumor associated with high mortality. Long non-coding RNAs (lncRNAs) are increasingly being recognized as its modulators. However, it remains mostly unexplored how lncRNAs are mediated by DNA methylation in GBM. The present study integrated multi-omics data to analyze the epigenetic dysregulation of lncRNAs in GBM. Widely aberrant methylation in the lncRNA promoters was observed, and the lncRNA promoters exhibited a more hypomethylated pattern in GBM. By combining transcriptional datasets, it was possible identify the lncRNAs whose transcriptional changes might be associated with the aberrant promoter methylation. Then, a methylation-mediated lncRNA regulatory network and functional enrichment analysis of aberrantly methylated lncRNAs showed that lncRNAs with different methylation patterns were involved in diverse GBM progression-related biological functions and pathways. Specifically, four lncRNAs whose increased expression may be regulated by the corresponding promoter hypomethylation were evaluated to have an excellent diagnostic effect and clinical prognostic value. Finally, through the construction of drug-target association networks, the present study identified potential therapeutic targets and small-molecule drugs for GBM treatment. The present study provides novel insights for understanding the regulation of lncRNAs by DNA methylation and developing cancer biomarkers in GBM.

• cd133
• diagnosis
• hnscc
• methylation
• prognosis
• prom1

• AC133 Antigen/genetics
• Asian People
• Biomarkers, Tumor/genetics
• China/epidemiology
• Data Mining
• Disease-Free Survival
• Female
• Gene Expression Regulation, Neoplastic
• Genetic Predisposition to Disease
• Head and Neck Neoplasms/genetics
• Head and Neck Neoplasms/mortality
• Humans
• Male
• Middle Aged
• Neoplasm Recurrence, Local/genetics
• Neoplasm Recurrence, Local/mortality
• Predictive Value of Tests
• Prognosis
• Proportional Hazards Models
• Squamous Cell Carcinoma of Head and Neck/genetics
• Squamous Cell Carcinoma of Head and Neck/mortality
• Survival Analysis

The recent discovery of cancer cell plasticity, i.e. their ability to reprogram into cancer stem cells (CSCs) either naturally or under chemotherapy and/or radiotherapy, has changed, once again, the way we consider cancer treatment. If cancer stemness is a reversible epigenetic state rather than a genetic identity, opportunities will arise for therapeutic strategies that remodel epigenetic landscapes of CSCs. However, the systematic use of DNA methyltransferase and histone deacetylase inhibitors, alone or in combination, in advanced solid tumors including colorectal cancers, regardless of their molecular subtypes, does not seem to be the best strategy. In this review, we first summarize the knowledge researchers have gathered on the epigenetic signatures of CSCs with the difficulty of isolating rare populations of cells. We raise questions about the relevant use of currently available epigenetic inhibitors (epidrugs) while the expression of numerous cancer stem cell markers are often repressed by epigenetic mechanisms. These markers include the three cluster of differentiation CD133, CD44 and CD166 that have been extensively used for the isolation of colon CSCs.and . Finally, we describe current treatment strategies using epidrugs, and we hypothesize that, using correlation tools comparing associations of relevant CSC markers with chromatin modifier expression, we could identify better candidates for epienzyme targeting.

• Cancer stem cells
• Colon cancer
• Epigenetics
• Chromatin modifying enzymes
• CD44
• CD133
• CD166

• CD133
• cancer stem cells
• chemoresistance
• colorectal cancer
• targeted therapy

The existence of radio- and chemotherapy-surviving cancer stem cells is currently believed to explain the inefficacy of anti-glioblastoma (GBM) therapies. The aim of this study was to determine if a therapeutic strategy specifically targeting GBM stem cells (GSC) would completely eradicate a GBM tumor. In both the in vitro and the in vivo models, ganciclovir therapy targeting proliferating GSC promotes the survival of a quiescent, stem-like cell pool capable of reproducing the tumor upon release of the therapeutic pressure. Images of small niches of therapy-surviving tumor cells show organized networks of vascular-like structures formed by tumor cells expressing CD133 or OCT4/SOX2. These results prompted the investigation of tumor cells differentiated to endothelial and pericytic lineages as a potential reservoir of tumor-initiating capacity. Isolated tumor cells with pericyte and endothelial cell lineage characteristics, grown under tumorsphere forming conditions and were able to reproduce tumors after implantation in mice.

• mtap deletion
• glioblastoma
• cancer stem cells
• epigenetics
• methylation

• Animals
• Apoptosis
• Biomarkers, Tumor/genetics
• Biomarkers, Tumor/metabolism
• Cell Proliferation
• Gene Expression Regulation, Neoplastic
• Glioblastoma/genetics
• Glioblastoma/metabolism
• Glioblastoma/pathology
• Humans
• Mice
• Neoplastic Stem Cells/metabolism
• Neoplastic Stem Cells/pathology
• Prognosis
• Purine-Nucleoside Phosphorylase/genetics
• Purine-Nucleoside Phosphorylase/metabolism
• Purines/metabolism
• Survival Rate
• Tumor Cells, Cultured
• Xenograft Model Antitumor Assays

• P50 CA190991 NCI NIH HHS
• R35 CA197264 NCI NIH HHS
• F30 CA206336 NCI NIH HHS
• R01 NS101074 NINDS NIH HHS
• P30 CA014236 NCI NIH HHS
• T32 GM007171 NIGMS NIH HHS

• Epigenetic modifications
• RNA epigenetic
• anticancer drugs
• cancer stem cells

• Cancer
• CpG islands
• DNA methylation

• Alternative Splicing
• Animals
• Biomarkers, Tumor/genetics
• CpG Islands/genetics
• DNA Methylation
• Gene Silencing
• Genes, Tumor Suppressor
• Genomic Imprinting
• Humans
• Models, Chemical
• Neoplasms/diagnosis
• Neoplasms/genetics
• Neoplasms/pathology
• Promoter Regions, Genetic
• Transcription, Genetic

Malignant glioma is the second leading cause of cancer-related death worldwide, and is known to exhibit a high degree of heterogeneity in its deregulation of different oncogenic pathways. The molecular subclasses of human glioma are not well known. Thus, it is crucial to identify vital oncogenic pathways in glioma with significant relationships to patient survival.

In this study, we devised a bioinformatics strategy to map patterns of oncogenic pathway activation in glioma, from the Gene Expression Omnibus (GEO). Bioinformatics analysis revealed that 749 genes were differentially expressed and classified into different glioma grades.

Using gene expression signatures, we identified three oncogenic pathways (MAPK signaling pathway, Wnt signaling pathway, and ErbB signaling pathway) deregulated in the majority of human glioma. Following gene microarray analysis, the gene expression profile in the differential grade glioma was further validated by bioinformatic analyses, with coexpression network construction. Furthermore, we found that cytochrome c oxidase subunit Vb (COX5B), the terminal enzyme of the electron transport chain, was the central gene in a coexpression network that transfers electrons from reduced cytochrome c to oxygen and, in the process, generates an electrochemical gradient across the mitochondrial inner membrane. The expression level of COX5B was then detected in 87 glioma tissues as well as adjacent normal tissues using immunohistochemistry. We found that COX5B was significantly upregulated in 67 of 87 (77.0%) glioma and glioblastoma tissues, compared with adjacent tissue (p<0.01). Furthermore, statistical analysis showed the COX5B expression level was significantly associated with clinical stage and lymph node status, while there were no correlations between COX5B expression and age or tumor size.

These data indicate that COX5B may be implicated in glioma pathogenesis and as a biomarker for identification of the pathological grade of glioma.

• COX5B
• bioinformatics
• biomarker
• glioblastoma

• DNA methylation
• cancer stem cells
• epigenetics
• histone modification
• luminal breast cancer
• microRNA
• tamoxifen resistance

Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC) and histone acetyltransferases (HAT). HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

• anti-angiogenic effect
• apoptosis
• autophagy
• cancer
• cell cycle arrest
• drug combinations
• histone deacetylase inhibitors
• histone deacetylases

• CD133
• DNA Methylation
• Expression
• GIST
• Immunohistochemistry
• Prominin 1

• AC133 Antigen/biosynthesis
• AC133 Antigen/genetics
• Adult
• Aged
• Aged, 80 and over
• Biomarkers, Tumor/analysis
• Biomarkers, Tumor/genetics
• DNA Methylation/genetics
• Disease-Free Survival
• Epigenesis, Genetic/genetics
• Female
• Gastrointestinal Neoplasms/genetics
• Gastrointestinal Stromal Tumors/genetics
• Gastrointestinal Stromal Tumors/mortality
• Gastrointestinal Stromal Tumors/pathology
• Gene Expression Regulation, Neoplastic/genetics
• Humans
• Immunohistochemistry
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Neoplastic Stem Cells/pathology
• Polymerase Chain Reaction
• Tissue Array Analysis

Pilocytic astrocytomas (PAs) are the most common pediatric central nervous system neoplasms. In the majority of cases these tumors are benign and receive favorable prognosis following gross total surgical resection. In patients with progressive or symptomatic tumors, aggressive surgical resection is generally not feasible, thus radiation or chemotherapy are accepted initial or adjuvant interventions. Due to serious long-lasting side-effects, radiation is limited in young children; therefore, chemotherapy is widely practiced as an adjuvant treatment for these patients. However, chemotherapy can promote the emergence of multidrug resistant tumor cells that are more malignant than those of the original tumor. CD133, a putative stem cell marker in normal tissue and malignant brain tumors, enhances multidrug resistant gene 1 (MDR1) expression following chemotherapy in adult malignant glioblastomas. This study examines the relationship between CD133 and MDR1 in pediatric PAs exposed to chemotherapy, with the goal of identifying therapeutic targets that manifest as a result of chemotherapy.

Slides were obtained for 15 recurrent PAs, seven of which had received chemotherapy prior to surgical treatment for the recurrent tumor. These samples, as well as primary tumor tissue slides from the same patients were used to investigate CD133 and MDR1 expression via immunofluorescence. Archived frozen tissue samples from the same patients were used to examine CD133, MDR1 and PI3K-Akt-NF-κB signaling mediators, via western blot. Two drug resistant pediatric PA cell lines Res186 and Res199 were also used to evaluate the role of CD133 on cell response to cytotoxic therapy.

CD133 and MDR1 were co-expressed and their expression was elevated in recurrent PAs from patients that had received chemotherapy, compared to patients that had not received chemotherapy. PI3K-Akt-NF-κB signaling mediator expression was also elevated in recurrent, chemotherapy-treated PA. Suppressing CD133 expression with siCD133 decreased levels of PI3K-Akt-NF-κB signaling mediators and MDR1, while increasing cell chemosensitivity, as indicated by quantification of apoptotic cells following chemotherapy.

CD133 contributes to multidrug resistance by regulating MDR1 levels via the PI3K-Akt-NF-κB signal pathway not only in adult glioblastomas, but also in pediatric PAs. Targeting CD133, adjuvant to conventional chemotherapy may improve outcomes for children with recurrent PA.

The online version of this article (doi:10.1186/s12943-017-0593-z) contains supplementary material, which is available to authorized users.

• CD133
• Chemotherapy
• MDR1
• Pediatric pilocytic astrocytoma

The pentaspan membrane glycoprotein prominin-1 (CD133) is widely used in medicine as a cell surface marker of stem and cancer stem cells. It has opened new avenues in stem cell-based regenerative therapy and oncology. This molecule is largely used with human samples or the mouse model, and consequently most biological tools including antibodies are directed against human and murine prominin-1. Although the general structure of prominin-1 including its membrane topology is conserved throughout the animal kingdom, its primary sequence is poorly conserved. Thus, it is unclear if anti-human and -mouse prominin-1 antibodies cross-react with their orthologs in other species, especially dog. Answering this issue is imperative in light of the growing number of studies using canine prominin-1 as an antigenic marker. Here, we address this issue by cloning the canine prominin-1 and use its overexpression as a green fluorescent protein fusion protein in Madin-Darby canine kidney cells to determine its immunoreactivity with antibodies against human or mouse prominin-1. We used immunocytochemistry, flow cytometry and immunoblotting techniques and surprisingly found no cross-species immunoreactivity. These results raise some caution in data interpretation when anti-prominin-1 antibodies are used in interspecies studies.

• AC133 Antigen/genetics
• AC133 Antigen/immunology
• Animals
• Antibodies, Monoclonal/metabolism
• Caco-2 Cells
• Cloning, Molecular/methods
• Dogs
• Humans
• Madin Darby Canine Kidney Cells
• Mice
• Species Specificity

• Deutsche Forschungsgemeinschaft
• Bundesministerium für Bildung und Forschung
• Sächsisches Staatsministerium für Wissenschaft und Kunst

Skin squamous-cell-carcinoma (SCC), is the main complication in long-term kidney-transplant recipients, and it can include donor-derived cells. Preclinical models demonstrated the involvement of epithelial mesenchymal transition (EMT) in the progression of skin SCC, and the role of Snail, an EMT transcription factor, in cancer stem-cell survival and expansion.

Here, we studied stem-cells and EMT expression in SCCs and concomitant actinic keratoses (AK) in kidney-transplant recipients.

In SCC and AK in 3 female recipients of male kidney-transplants, donor-derived Y chromosome in epidermal stem cells was assessed using combined XY-FISH/CD133 immunostaining, and digital-droplet-PCR on laser-microdissected CD133 expressing epidermal cells.

For EMT study, double immunostainings of CD133 with vimentin or snail and slug, electron microscopy and immunostainings of keratinocytes junctions were performed. Digital droplet PCR was used to check CDH1 (E-cadherin) expression level in laser-microdissected cells co-expressing CD133 and vimentin or snail and slug.

The numbers of Y-chromosome were assessed using digital droplet PCR in laser-microdissected cells co-expressing CD133 and vimentin, or snail and slug, and in CD133 positive cells not expressing any EMT maker.

We identified donor-derived stem-cells in basal layers and invasive areas in all skin SCCs and in concomitant AKs, but not in surrounding normal skin.

The donor-derived stem-cells expressed the EMT markers, vimentin, snail and slug in SCCs but not in AKs. The expression of the EMT transcription factor, SNAI1, was higher in stem-cells when they expressed vimentin. They were located in invasive areas of SCCs. In these areas, the expressions of claudin-1 and desmoglein 1 were reduced or absent, and within the basal layer there were features of basal membrane disappearance.

Donor-derived stem cells were in larger numbers in stem cells co-expressing vimentin or snail and slug than in stem cells not expressing any EMT marker.

We identified here donor-derived stem cells within skin SCC in kidney-transplant recipients. They were located in invasive areas of SCC and had EMT characteristics.

• Pathology Section
• chimerism
• epithelial mesenchymal transition
• kidney transplant
• squamous cell carcinoma
• stem-cell

Cluster of differentiation (CD)133 is an important cell surface marker of glioma stem cells (GSCs). The transcription of the CD133 gene is controlled by five alternative promoters (P1, P2, P3, P4 and P5), which are expressed in a tissue-specific manner. In the present study, gene recombination technology was used to construct two types of gene expression vectors that contained the P1 promoter of the CD133 gene, which regulated either the neomycin-resistance gene or the herpes simplex virus thymidine kinase (HSV-TK) gene. Following the stable transfection of U251 glioblastoma cells with these two gene vectors, the cells expressing the P1 promoter that regulated the neomycin-resistance gene were named CD133 (+) cells, while the cells expressing the P1 promoter regulating the HSV-TK gene were called CD133 (−) cells. The expression of CD133 was detected by flow cytometry and reverse transcription-quantitative polymerase chain reaction. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to assess cell proliferation ability, while the cell cycle was analyzed by flow cytometry, and a clone formation test was performed to evaluate the invasive capability of the cells. The results demonstrated that, due to CD133 expression, the cell proliferation ability and the invasive capability of CD133 (+) cells were significantly higher than those of CD133 (−) cells. In conclusion, the present study successfully established a novel method of screening GSCs in U251 cells based on the P1 promoter of the CD133 gene.

• CD133
• P1 promoter
• U251 cells
• glioma stem cells
• screening

CD133 has played a pivotal role in the identification and isolation of brain tumor stem cells. The correlation between CD133 expression in tumor tissues with patients survival is still controversial. CD133 expression is determinated by methylation status of the promoter region 1–3. Aberrant methylation of CD133 was observed in glioblastoma. To date, a direct link between CD133 methylation and patient outcome has not been established.To address this question, we studied CD133 expression and promoter methylation in a series of 170 gliomas of various grade and histology, and investigated the correlation of CD133 expression and promoter methylation with patient outcome.We detected five CD133 promoter methylation patterns in 170 glioma samples: methylation only (M+, U−), unmethylation only (M−, U+), both methylation and unmethylation equally (M+, U+), high methylation and low unmethylation (M+, Ul), and low methylation and high unmethylation (Ml, U+). By multivariate survival analysis, we found CD133 promoter methylation status was significant (P < 0.01) prognostic factors for adverse progression-free survival and overall survival independent of tumor grade, extent of resection, or patient age. CD133 immunostaining showed considerable variability among tumors. While, there was lack of correlation between CD133 protein expression and patient’s survival. Furthermore, no correlation between CD133 protein expression and CD133 promoter methylation status was observed (Kw = −0.165).CD133 promoter methylation status in glioma is closely correlated with patient survival, which suggest CD133 promoter methylaiton pattern is a promising tool for diagnostic purposes.

• Brain tumor stem cells
• CD133
• Gliomas
• Patient outcome
• Promoter methylation

• Adult
• Aged
• Cell Line, Tumor
• Colorectal Neoplasms/diagnosis
• Colorectal Neoplasms/genetics
• Colorectal Neoplasms/mortality
• DNA Methylation
• Female
• Gene Knockdown Techniques
• Humans
• Male
• Middle Aged
• Neoplasm Grading
• Neoplasm Metastasis
• Neoplasm Staging
• Neoplastic Stem Cells/metabolism
• Neoplastic Stem Cells/pathology
• Prognosis
• Promoter Regions, Genetic
• Receptors, G-Protein-Coupled/genetics

Novel therapeutic strategies are needed to overcome cancer recurrence, metastasis, and resistance to chemo- and radiotherapy. Cancer stem cells (CSCs) are major contributors to the malignant transformation of cells due to their capacity for self-renewal. Although various CSC markers have been identified in several types of tumors, they are primarily used as cancer-prediction markers and for the isolation of CSC populations. CD133, one of the best-characterized CSC markers in distinct solid tumor types, was shown to be correlated with CSC tumor-initiating capacity; however, the regulation of CD133 expression and its function in cancer are poorly understood. Here, we show that CD133 expression is negatively regulated by direct binding of the p53 tumor suppressor protein to a noncanonical p53-binding sequence in the CD133 promoter. Binding of p53 recruits Histone Deacetylase 1 (HDAC1) to the CD133 promoter and subsequently suppresses CD133 expression by reducing histone H3 acetylation. Furthermore, CD133 depletion suppresses tumor cell proliferation, colony formation, and the expression of core stemness transcription factors including NANOG, octamer-binding transcription factor 4 (OCT4), SOX2, and c-MYC. Critically, the anti-proliferative effects of p53 are antagonized by rescue of CD133 expression in a p53 overexpressing cell line, indicating that the tumor suppressive activity of p53 might be mediated by CD133 suppression. Taken together, our results suggest that p53-mediated transcriptional regulation of CD133 is a key underlying mechanism for controlling the growth and tumor-initiating capacity of CSCs and provide a novel perspective on targeting CSCs for cancer therapy.

Subtelomeric regions dynamically change their epigenetic pattern during development and progression of several malignancies and degenerative disorders. However, DNA methylation of human subtelomeres and their correlation to telomere length (TL) remain undetermined in glioma.

Herein, we report on the selective changes in subtelomeric DNA methylation at the end of five chromosomes (Chr.) (7q, 8q. 18p, 21q, and XpYp) and ascertain their correlation with TL in patients with glioma. Subtelomeric methylation level was invariably higher in glioma patients compared to the control group, irrespective of their age and tumor grade. In particular, a significant increase in methylation was observed at the subtelomeric CpG sites of Chr. 8q, 21q, and XpYp in tissues, obtained from the brain tumor of glioma patients. In contrast, no significant change in methylation was observed at the subtelomere of Chr. 7q and 18p. Selective changes in the subtelomeric methylation level, however, did not show any significant correlation to the global TL. This observed phenomenon was validated in vitro by inducing demethylation in a glioblastoma cell line (SF-767) using 5-azacytidine (AZA) treatment. AZA treatment caused significant changes in the subtelomeric methylation pattern but did not alter the TL, which supports our hypothesis.

DNA methylation level dramatically increased at the subtelomere of Chr.8q, 21q, and XpYp in malignant glioma, which could be used as an early epigenetic diagnostic biomarker of the disease. Alterations in subtelomeric methylation, however, have no effects on the TL.

The online version of this article (doi:10.1186/s13148-015-0140-y) contains supplementary material, which is available to authorized users.

• Epigenetic biomarker
• Glioma
• Subtelomeric DNA methylation
• Telomere length

While genome-wide differential DNA methylation regions (DMRs) have been extensively identified, the comprehensive prioritization of their functional importance is still poorly explored. Here, we aggregated multiple data resources rooted in the genome, epigenome and transcriptome to systematically prioritize functional DMRs (fDMRs) in colorectal cancer (CRC). As demonstrated, the top-ranked fDMRs from all of the data resources showed a strong enrichment for known methylated genes. Additionally, we analyzed those top 5% DMR-coupled coding genes using functional enrichment, which resulted in significant disease-related biological functions in contrast to the tail 5% genes. To further confirm the functional importance of the top-ranked fDMRs, we applied chromatin modification alterations of CRC cell lines to characterize their functional regulation. Specifically, we extended the utility of the top-ranked DMR-coupled genes to serve as classification and survival biomarkers, which showed a robust performance across diverse independent data sets. Collectively, our results established an integrative framework to prioritize fDMRs, which could help characterize aberrant DNA methylation-induced potential mechanisms underlying tumorigenesis and uncover epigenome-based biomarkers for clinical diagnosis and prognosis.

• breast cancer
• epigenetic modifications
• estrogen receptors
• progesterone receptors

• Cancer stem cell
• Chemo-resistance
• Chemotherapy
• Chromatin remodelling
• DNA methylation
• Epigenetic reprogramming

• cancer stem cells
• dnmt1
• microenvironment
• reprogramming
• hcc

Glioblastoma are the most frequent and malignant human brain tumors, having a very poor prognosis. The enhanced radio- and chemoresistance of glioblastoma and the glioblastoma stem cells might be the main reason why conventional therapies fail. The second messenger cyclic AMP (cAMP) controls cell proliferation, differentiation, and apoptosis. Downregulation of cAMP sensitizes tumor cells for anti-cancer treatment. Opioid receptor agonists triggering opioid receptors can activate inhibitory G_i proteins, which, in turn, block adenylyl cyclase activity reducing cAMP. In this study, we show that downregulation of cAMP by opioid receptor activation improves the effectiveness of anti-cancer drugs in treatment of glioblastoma. The µ-opioid receptor agonist D,L-methadone sensitizes glioblastoma as well as the untreatable glioblastoma stem cells for doxorubicin-induced apoptosis and activation of apoptosis pathways by reversing deficient caspase activation and deficient downregulation of XIAP and Bcl-x_L, playing critical roles in glioblastomas’ resistance. Blocking opioid receptors using the opioid receptor antagonist naloxone or increasing intracellular cAMP by 3-isobutyl-1-methylxanthine (IBMX) strongly reduced opioid receptor agonist-induced sensitization for doxorubicin. In addition, the opioid receptor agonist D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux, whereas doxorubicin increased opioid receptor expression in glioblastomas. Furthermore, opioid receptor activation using D,L-methadone inhibited tumor growth significantly in vivo. Our findings suggest that opioid receptor activation triggering downregulation of cAMP is a promising strategy to inhibit tumor growth and to improve the effectiveness of anti-cancer drugs in treatment of glioblastoma and in killing glioblastoma stem cells.

• D,L-methadone
• apoptosis
• cAMP
• chemoresistance
• chemotherapy
• glioblastoma
• glioblastoma stem cells
• opioid receptor

PROM1 is the gene encoding prominin-1 or CD133, an important cell surface marker for the isolation of both normal and cancer stem cells. PROM1 transcripts initiate at a range of transcription start sites (TSS) associated with distinct tissue and cancer expression profiles. Using high resolution Cap Analysis of Gene Expression (CAGE) sequencing we characterize TSS utilization across a broad range of normal and developmental tissues. We identify a novel proximal promoter (P6) within CD133⁺ melanoma cell lines and stem cells. Additional exon array sampling finds P6 to be active in populations enriched for mesenchyme, neural stem cells and within CD133⁺ enriched Ewing sarcomas. The P6 promoter is enriched with respect to previously characterized PROM1 promoters for a HMGI/Y (HMGA1) family transcription factor binding site motif and exhibits different epigenetic modifications relative to the canonical promoter region of PROM1.

• AC133 antigen
• PROM1 protein
• cancer stem cells
• genetic
• human
• melanoma
• promoter regions
• transcription start site

• AC133
• CD133
• RNA interference
• high-throughput screening
• membrane proteins
• short hairpin RNA

CD133 is a cellular surface protein that has been reported to be a cancer stem cell marker, and thus it is considered to be a potential target for cancer treatment. However, the mechanism regulating CD133 expression is not yet understood. In this study, we analyzed the activity of five putative promoters (P1–P5) of CD133 in human embryonic kidney (HEK) 293 cells and colon cancer cell line WiDr, and found that the activity of promoters, particularly of P5, is elevated by overexpression of hypoxia-inducible factors (HIF-1α and HIF-2α). Deletion and mutation analysis identified one of the two E-twenty six (ETS) binding sites (EBSs) in the P5 region as being essential for its promoter activity induced by HIF-1α and HIF-2α. In addition, a chromatin imunoprecipitation assay demonstrated that HIF-1α and HIF-2α bind to the proximal P5 promoter at the EBSs. The immunoprecipitation assay showed that HIF-1α physically interacts with Elk1; however, HIF-2α did not bind to Elk1 or ETS1. Furthermore, knockdown of both HIF-1α and HIF-2α resulted in a reduction of CD133 expression in WiDr. Taken together, our results revealed that HIF-1α and HIF-2α activate CD133 promoter through ETS proteins.

• AC133 Antigen
• Antigens, CD/genetics
• Antigens, CD/metabolism
• Basic Helix-Loop-Helix Transcription Factors/physiology
• Binding Sites
• Cell Hypoxia
• Cell Line, Tumor
• Gene Expression
• Gene Knockdown Techniques
• Glycoproteins/genetics
• Glycoproteins/metabolism
• HEK293 Cells
• Humans
• Hypoxia-Inducible Factor 1, alpha Subunit/physiology
• Peptides/genetics
• Peptides/metabolism
• Promoter Regions, Genetic
• Protein Binding
• Proto-Oncogene Protein c-ets-1/physiology
• Transcriptional Activation
• Up-Regulation
• ets-Domain Protein Elk-1/physiology

According to the cancer stem cell (CSC) model, higher CD133 expression in tumor tissue is associated with metastasis and poor prognosis in colon cancer. As such, the CD133-positive (CD133⁺) subpopulation of cancer cells is believed to play a central role in tumor development and metastatic progression. Although CD133⁺ cells are believed to display more CSC-like behavior and be solely responsible for tumor colonization, recent research indicates that CD133⁻ cells from metastatic colon tumors not only also possess colonization capacity but also promote the growth of larger tumors in a mouse model than CD133⁺ cells, suggesting that an alternative mechanism of metastasis exists. This study investigated this possibility by examining the cell viability, tumorigenicity, and proliferation and growth capacity of the CD133⁺ and CD133⁻ subpopulations of the SW620 cell line, a human metastatic colon cancer cell line, in both an in vitro cell model and an in vivo mouse model. While both SW620 ^CD133− and SW620^CD133+ cells were found to engage in bidirectional cell-type switching in reaction to exposure to environmental stressors, including hypoxia, a cell adhesion-free environment, and extracellular matrix stimulation, both in vitro and in vivo, CD133⁻ cells were found to have a growth advantage during early colonization due to their greater resistance to proliferation inhibition. Based on these findings, a hypothetical model in which colon cancer cells engage in cell-type switching in reaction to exposure to environmental stressors is proposed. Such switching may provide a survival advantage during early colonization, as well as that explain previous conflicting observations.

Cancer stem cells (CSCs) are notorious for their capacity of tumor progression, metastasis or resistance to chemo-radiotherapy. However, the undisputed role of cancer stem marker, CD133, in colorectal cancers (CRCs) is not clear yet.

We assessed 271 surgically-resected stage II and III primary CRCs with (171) and without (100) adjuvant therapy after surgery. CD133 expression was analyzed by immunohistochemical (IHC) staining and real-time RT-PCR. CD133 promoter methylation was quantified by pyrosequencing.

The CD133 IHC expression was significantly correlated with mRNA expression (p=0.0257) and inversely correlated with the promoter methylation (p=0.0001). CD133 was expressed more frequently in rectal cancer (p=0.0035), and in moderately differentiated tumors (p=0.0378). In survival analysis, CD133 expression was not significantly correlated with overall survival (OS) (p=0.9689) as well as disease-free survival (DFS) (p=0.2103). However, CD133+ tumors were significantly associated with better OS in patients with adjuvant therapy compared to those without adjuvant therapy (p<0.0001, HR 0.125, 95% CI 0.052-0.299). But the patients with CD133- tumors did not show any significant difference of survival according to adjuvant therapy (p=0.055, HR 0.500, 95% CI 0.247-1.015).

In stage II and III CRCs, CD133 IHC expression may signify the benefit for adjuvant therapy although it is not an independent prognostic factor.

• Basic Helix-Loop-Helix Transcription Factors/genetics
• Cell Line, Tumor
• DNA Methylation
• Drug Resistance, Neoplasm
• Fluorouracil/therapeutic use
• Gene Expression Regulation, Neoplastic
• Humans
• Promoter Regions, Genetic
• Stomach Neoplasms/drug therapy
• Stomach Neoplasms/genetics
• Stomach Neoplasms/mortality
• Up-Regulation

• AC133 Antigen
• Animals
• Antibodies, Monoclonal/pharmacology
• Antibodies, Monoclonal/toxicity
• Antigens, CD/genetics
• Antigens, CD/immunology
• Antigens, CD/metabolism
• Apoptosis/drug effects
• Autophagy/drug effects
• Carcinoma, Hepatocellular/genetics
• Carcinoma, Hepatocellular/metabolism
• Cell Line, Tumor
• Cell Survival
• Glucose/metabolism
• Glycoproteins/genetics
• Glycoproteins/immunology
• Glycoproteins/metabolism
• Humans
• Liver Neoplasms/genetics
• Liver Neoplasms/metabolism
• Lysosomes/metabolism
• Male
• Mice
• Peptides/genetics
• Peptides/immunology
• Peptides/metabolism
• Phagosomes/metabolism
• Transplantation, Heterologous