Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs.
AC133 Antigen/genetics/metabolism ; Animals ; Antineoplastic Agents/pharmacology/therapeutic use ; Cell Differentiation/*drug effects ; Cell Line, Tumor ; Cell Survival/drug effects ; Chromones/pharmacology/therapeutic use ; Colorectal Neoplasms/drug therapy/metabolism/pathology ; Humans ; Imidazoles/pharmacology/therapeutic use ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Morpholines/pharmacology/therapeutic use ; Neoplastic Stem Cells/cytology/drug effects/metabolism ; Paclitaxel/pharmacology/therapeutic use ; Phosphatidylinositol 3-Kinases/*antagonists & inhibitors/metabolism ; Quinolines/pharmacology/therapeutic use ; SOXB1 Transcription Factors/genetics/metabolism ; Signal Transduction/*drug effects ; Sirolimus/pharmacology/therapeutic use ; TOR Serine-Threonine Kinases/*antagonists & inhibitors/metabolism ; Xenograft Model Antitumor Assays

OBJECTIVETo explore whether miR-200b suppresses tumor cell invasion by targeting PROM1, thus to reveal the molecular mechanism that miR-200b functions as a tumor suppressor in glioma.

METHODSPROM1 3'UTR-luciferase vector was constructed and dual-luciferase reporter gene assay was employed to examine the effect of miR-200b on luciferase activity. Human glioblastoma U87 cells were transfected with miR-200b mimics, and next qRT-PCR and Western blotting were performed to detect the expressions of PROM1 mRNA and protein. The effect of PROM1 down-regulation on invasion was observed after PROM1 siRNA were transfected into U87 cells.

RESULTSThe miR-200b bound to the 3'-untranslated region (UTR) of PROM1 and inhibited the luciferase activity. Its luciferase activity was down-regulated by 57.0% (P < 0.01). PROM1 protein and mRNA expressions were significantly down-regulated when miR-200b was overexpressed in the U87 cells (P < 0.05). siRNA-mediated down-regulation of PROM1 suppressed the potential of cell invasion. The invasion ability of SKOV3 cells after transfection with siRNA-PROM1 was significantly lower than that in the negative control cells (P < 0.05).

CONCLUSIONmiR-200b may suppress cell invasion by targeting PROM1 in glioma.

3' Untranslated Regions ; AC133 Antigen ; Antigens, CD ; metabolism ; Cell Line, Tumor ; Down-Regulation ; Genes, Reporter ; Genes, Tumor Suppressor ; Genetic Vectors ; Glioblastoma ; genetics ; metabolism ; Glycoproteins ; metabolism ; Humans ; Luciferases ; MicroRNAs ; metabolism ; Peptides ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; Transfection

Several studies have shown that the tumor endothelial cells are different from the normal tissue endothelial cells. These tumor endothelial cells may contribute to tumor neo-vasculogenesis. This study was purposed to analyze the biologic features and determine the expression level of CD133 and BCR/ABL fusion gene in circulating endothelial cells (CEC) isolated from peripheral blood of CML patients, as well as to investigate the role of CEC in disease progression. Mononuclear cells were isolated from peripheral blood by density gradient centrifugation; CEC were sorted by MACS and harvested in the endothelial growth medium. The morphologic features of CEC were observed by microscopy, the cell growth rate was calculated by cell counting, and the cells were identified by immunofluorescence staining for the expression of CD31,CD34,VWF and CD133. The expression of BCR/ABL fusion gene was examined by FISH in 12 CML patients. The results indicated that the isolated CEC displayed the typical cobble-stone morphology. These cells could be identified by the positive immunofluorescence staining for CD31, CD34 and VWF, and showed more increased proliferative potential as compared to that of healthy donors. It was found that the positive rate of CD133 was 31.29% in CML patients, which was significantly different from that of healthy donors (P < 0.05). In 12 CML patients, CEC carried the same chromosome aberration as the leukemia cells (10.77%). Higher expression level of CD133 and BCR/ABL fusion gene positively correlated with progression of disease. It is concluded that the CEC may participate in invasion and angiogenesis in patients with CML and possibly correlate to the spreading and progression of the disease.
AC133 Antigen ; Adult ; Antigens, CD ; metabolism ; Cell Proliferation ; Endothelial Cells ; metabolism ; Female ; Fusion Proteins, bcr-abl ; genetics ; metabolism ; Glycoproteins ; metabolism ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism ; pathology ; Male ; Middle Aged ; Neovascularization, Pathologic ; Peptides ; metabolism ; Young Adult

OBJECTIVE: To investigate the self-renewal mechanism of CD133+ cancer stem cells from Hep-2 cell line. METHOD: The CD133+ cells were sorted by flow cytometry from Hep-2 cell line. Then the sorted CD133+ cells were cultured in RPMI1640. The ability of self-renewal of CD133+ cells were tested by MTT assay. mRNA and protein expression of self-renewal related genes were detected by western blot and RT- PCR. RESULT: (3.10 ± 0.21)% of Hep-2 cells expressed the membrane antigen CD133. CD133+ fraction was raised to (90.20 ± 5.51)% by flow cytometry. In vitro culture and growth curve showed CD133+ cells had more active proliferation ability than CD133- cells, which showed statistically significant difference between these two group (P < 0.01). RT- PCR and western blot results showed upregulated mRNA and protein expression of Fas, c-myc, survivin in CD133+ group (P < 0.01). In the same time, the ratio of Bcl-2/Bax gene expression was obviously increased in CD133+ group. Self-renewal related gene such as β-catenin, SHH, SMOH and Bmi-1,Gli-1 were all up-regulated in CD133+ group both in mRNA and protein. On the contrary, PTCH gene was down-regulated. CONCLUSION CD133 positive cells are a small proportion of a Hep-2 cell line. The results of this experiment verified that CD133 positive cells owned the properties of cancer stem cells. Upregulated anti-apoptotic gene is the foundatiom of self-renewal mechanism of CD133+ cells. Cancer stem cells related signal pathways such as Hedgehog, Wnt and Bmi-1 pathway are in state of activation. The identification of self-renewal mechanism about cancer stem cell provides a powerful tool to investigate the tumorigenic process in the larynx and to develop therapies targeting to these signal pathways.
AC133 Antigen ; Antigens, CD ; Apoptosis ; Cell Physiological Phenomena ; physiology ; Down-Regulation ; Flow Cytometry ; Glycoproteins ; Humans ; Laryngeal Neoplasms ; Neoplastic Stem Cells ; physiology ; Patched Receptors ; Patched-1 Receptor ; Peptides ; Receptors, Cell Surface ; genetics ; metabolism ; Signal Transduction ; beta Catenin ; genetics

OBJECTIVETo screen and identity genes related to CD133(+)CD200(+) colorectal cancer stem cells.

METHODSThe two subpopulations of colorectal cancer cells, namely CD133(+)CD200(+) and CD133(-)CD200(-) cells, were sorted and verified by flow cytometry. The gene expression profiles of CD133(+)CD200(+)and CD133(-)CD200(-) colorectal cancer cells were examined using Affymetrix Human U133 Plus2.0 genome-wide genechip. The differentially expressed genes between the two cell subpopulations were analyzed to identify the genes responsible for the main effect in association with colorectal cancer stem cells. Real-time quantitative PCR was performed to confirm some of the differentially expressed genes identified by genechip.

RESULTSThe genechip result showed that 655 genes were differentially expressed in CD133(+)CD200(+) colorectal cancer stem cells by at least 3 folds, including 290 up-regulated and 365 down-regulated ones. Bioinformatics analysis and gene co-expression network building identified 3 genes (MDM2, PRKACG, and CACNA1G) with specific expression in CD133(+)CD200(+) colorectal cancer stem cells, and this result was confirmed by real-time quantitative PCR analysis.

CONCLUSIONA specific gene expression profile of colorectal cancer stem cells has been established through screening and identifying genes related to CD133(+)CD200(+)colorectal cancer stem cells by gene genechip technique, which provides a basis for further study of gene targeting therapy of colorectal cancer.

AC133 Antigen ; Antigens, CD ; genetics ; metabolism ; Colorectal Neoplasms ; genetics ; Flow Cytometry ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Glycoproteins ; genetics ; metabolism ; Humans ; Neoplastic Stem Cells ; metabolism ; Oligonucleotide Array Sequence Analysis ; Peptides ; genetics ; metabolism ; Transcriptome

OBJECTIVEto investigate the effects of antidiabetic drug metformin on proliferation and apoptosis in human hepatocellular carcinoma cell line Huh-7 cells.

METHODSHuh-7 cells were treated with metformin at different concentrations. Cell viability was determined by MTT assay. Cell apoptosis and CD133(+) expression rate were detected by flow cytometery (FCM). Expressions of PTEN, Akt, p-Akt, Bcl-2, Bax proteins in the cells were measured by Western blot. The effect of metformin on the hepatosphere formation was observed in the serum-free suspension culture. Reverse transcription-polymerase chain reaction (RT-PCR) was used to validate the expression levels of stemness marker genes CD133, β-catenin, and ABCG2 mRNA in the hepatospheres.

RESULTSThe proliferation of Huh-7 cells was inhibited by metformin in a dose- and time-dependent manner. The early and late cell apoptosis rates induced by metformin at dose of 10 mmol/L for 48 hrs were (22.29 ± 0.8)% and (13.87 ± 1.2)%, respectively, and 25 mmol/L for 48 hrs (15.28 ± 2.1)% and (25.89 ± 2.3)%, respectively. Western blotting results revealed that the expression of CD133, phosphorylated Akt and the Bcl-2/Bax ratio were downregulated, and PTEN was upregulated in the Huh-7 cells after treated with 25 mmol/L metformin for 48 hrs. Metformin inhibited the formation of hepatospheres. Metformin also downregulated the expression of several cancer stem cells (CSCs)-related genes which are involved in the signaling pathways governing the self-renewal, proliferation and differentiation of CSCs in the hepatospheres.

CONCLUSIONSMetformin inhibits the proliferation of human hepatocellular carcinoma Huh-7 cells and enhances their apoptosis in vitro. It may be related to the downregulation of PI3K/Akt signal pathway and selectively targeting CD133(+) cells.

AC133 Antigen ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; Antigens, CD ; genetics ; metabolism ; Antineoplastic Agents ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Dose-Response Relationship, Drug ; Glycoproteins ; genetics ; metabolism ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Metformin ; administration & dosage ; pharmacology ; Neoplasm Proteins ; genetics ; metabolism ; PTEN Phosphohydrolase ; metabolism ; Peptides ; genetics ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; RNA, Messenger ; metabolism ; Signal Transduction ; drug effects ; Time Factors ; bcl-2-Associated X Protein ; metabolism ; beta Catenin ; metabolism

OBJECTIVETo investigate the changes in proliferation, invasiveness, clone sphere formation and chemosensitivity of human gastric cancer cell lines of KATO-III CD133(+) cells transfected with small interfering RNA (siRNA) against CD133 gene.

METHODSCD133(+) cells of KATO-III cell lines were isolated by magnetic activated cell sorting (MACS). CD133 siRNA was designed and synthesized, and then transfected into KATO-III CD133(+) cells. Cell fluorescence counting under confocal laser scanning microscope was used to determine the transfection efficiency after transfection with the CD133 FITC-siRNA. The knock-down effect of the CD133 gene and expression of epithelial-mesenchymal transition (EMT)-related factors were detected by RT-PCR and Western blotting. Cell counting kit-8 assay (CCK-8), transwell chamber and colony sphere forming assay were performed to measure the variation of cell proliferative, invasive, colony formation viability and chemosensitivity to 5-FU after the above-mentioned treatment.

RESULTSThe transfection efficiency was (87.7±8.1)%. The CD133 mRNA and protein expression levels in the interference group were lower than those in negative control group. Twenty-four, 48 and 72 hours after transfection, cells proliferation activity was significantly inhibited in the interference group compared with negative control group, (all P<0.01). Seventy-two hours after transfection, compared with negative control group, cells proliferation activity was reduced by (52.1±8.0)%. The invasive cell number reduced (41.7±6.0 vs. 130.3±11.0, P<0.05) and clone formation rate decreased significantly [(24.3±4.3)% vs. (45.1±6.4)%, P<0.01] in the interference group. EMT-related gene E-cadherin protein expression increased, while the Snail and N-cadherin protein expression reduced in the interference group (all P<0.01). The cells sensitivity to 5-FU was significantly enhanced in the interference group, and the cell inhibition rate of 5-Fu was (62.4±3.3)%, higher than that in negative control group [(21.5±2.2)%, P<0.01].

CONCLUSIONSThe expression of CD133 gene plays an important role in cell proliferation, invasiveness, colony formation and resistance to chemotherapy of KATO-III CD133(+) gastric cancer cells. It suggests that CD133 can be used as one of surface markers for detection of gastric cancer stem cells. Inhibition of CD133 expression may be a promising way for gastric cancer biotherapy.

AC133 Antigen ; Antigens, CD ; genetics ; metabolism ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Fluorouracil ; pharmacology ; Glycoproteins ; genetics ; metabolism ; Humans ; Peptides ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Transfection

BACKGROUNDMounting evidence suggests that tumors are histologically heterogeneous and are maintained by a small population of tumor cells termed cancer stem cells. CD133 has been identified as a candidate marker of cancer stem cells in laryngeal carcinoma. This study aimed to analyze the chemoresistance of CD133(+) cancer stem cells.

METHODSThe response of Hep-2 cells to different chemotherapeutic agents was investigated and the expression of CD133 was studied. Fluorescence-activated cell sorting analysis was used to identify CD133, and the CD133(+) subset of cells was separated and analyzed in colony formation assays, cell invasion assays, chemotherapy resistance studies, and analyzed for the expression of the drug resistance gene ABCG2.

RESULTSAbout 1% - 2% of Hep-2 cells were CD133(+) cells, and the CD133(+) proportion was enriched by chemotherapy. CD133(+) cancer stem cells exhibited higher potential for clonogenicity and invasion, and were more resistant to chemotherapy. This resistance was correlated with higher expression of ABCG2.

CONCLUSIONSThis study suggested that CD133(+) cancer stem cells are more resistant to chemotherapy. The expression of ABCG2 could be partially responsible for this. Targeting this small population of CD133(+) cancer stem cells could be a strategy to develop more effective treatments for laryngeal carcinoma.

AC133 Antigen ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; Antigens, CD ; genetics ; metabolism ; Antineoplastic Agents ; pharmacology ; Blotting, Western ; Carcinoma ; genetics ; metabolism ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Flow Cytometry ; Fluorouracil ; pharmacology ; Glycoproteins ; genetics ; metabolism ; Humans ; Laryngeal Neoplasms ; genetics ; metabolism ; Neoplasm Proteins ; genetics ; metabolism ; Neoplastic Stem Cells ; cytology ; drug effects ; metabolism ; Paclitaxel ; pharmacology ; Peptides ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

BACKGROUND AND OBJECTIVERadiotherapy (RT) is a major non-surgical modality in the comprehensive treatment for colorectal adenocarcinoma. The radioresistance of cancer stem cells (CSCs) is a key factor that influences therapeutic effectiveness. This study was to investigate the effects of specific chromosome structure and histone modification in CSCs in colorectal adenocarcinoma radioresistance.

METHODSSamples were collected from resected human colorectal adenocarcinomas. Subcutaneous colorectal cancer model was established in nude mice. Immunohistochemistry showed that xenografts generated from bulk colorectal cancer cells resembled the original tumor specimen. Flow cytometry was performed to sort CSCs (CD133+) and non-CSCs (CD133-) from both resected samples of colorectal adenocarcinoma and xenograft before and after high single-dose radiation. The markers labeling heterochromatin (H3K9me3, HP1-alpha and H3K4me1) and euchromatin (H3K4me3) in CD133+ and CD133- nucleus were detected by immunofluorescence.

RESULTSThere was distinct difference in chromatin structure between colorectal CSCs (CD133+) and non-CSCs (CD133-). The chromatin displayed compact patches in CD133+ nucleus, but loosely latticed structure in CD133- nucleus; immunofluorescence verified that the compact patches existing in CSCs was generated from heterochromatin construction. In addition, the vacuole-like defect in heterochromatin regions of CSCs was observed within 24 h after exposure to 10 gray (Gy) single-dose RT. Interestingly, this phenomenon was repaired from 96 h, and recovered to dense plaque structure in heterochromatin regions of CSCs after 144 h. However, no significant difference in non-CSCs was observed after RT exception for a loose chromatin structure.

CONCLUSIONSCSCs play a role in radiosensitivity in colorectal cancer. The mechanism may be related to heterochromatin formation and histone methylation.

AC133 Antigen ; Adenocarcinoma ; pathology ; radiotherapy ; Adult ; Aged ; Aged, 80 and over ; Animals ; Antigens, CD ; metabolism ; Cell Nucleus ; genetics ; pathology ; Colorectal Neoplasms ; pathology ; radiotherapy ; Female ; Glycoproteins ; metabolism ; Heterochromatin ; metabolism ; Histones ; metabolism ; Humans ; Male ; Methylation ; Mice ; Mice, Nude ; Middle Aged ; Neoplasm Transplantation ; Neoplastic Stem Cells ; pathology ; radiation effects ; Particle Accelerators ; Peptides ; metabolism ; Radiation Dosage ; Radiation Tolerance

BACKGROUND AND OBJECTIVERecently, the theory of cancer stem cells (CSCs) has presented new targets and orientations for tumor therapy. The major difficulties in researching CSCs include their isolation and purification. The aim of this study is to identify and characterize the side population (SP) cells in small cell lung cancer (SCLC) cell line H446, which lays the foundation for the isolation and purification of CSCs.

METHODSFluorescence-activated cell sorting (FACS) was used to sort SP and non-SP (NSP) cells from H446. Both subgroups were cultivated to survey the capacity to form into suspended tumor cell spheres. Reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR were used to evaluate the expression levels of the mRNA of CD133, ABCG2, and nucleostemin in both subgroups. The capacity of proliferation and the differences in drug resistance of both subgroups and unsorted cells were tested by the MTT method. The differentiation ability of both subgroups was determined by FACS. Proliferation was determined by subcutaneous tumor formation in nude mice.

RESULTSThe percent of Hoechst 33342 negative cells was about (5.1 +/- 0.2)% in H446 by fluorescence microscopy. The percent of SP cells was (6.3 +/- 0.1)% by flow cytometry. SP cells had a stronger capability of forming into tumor spheres than NSP cells. The mRNA expression levels of ABCG2, CD133, and nucleostemin in SP cells were 21.60 +/- 0.26, 7.10 +/- 0.14, and 1.02 +/- 0.08 folds higher than that in NSP cells (P < 0.01, P < 0.01, and P > 0.05, respectively). In vivo, SP cells showed better proliferative ability and tougher viability when treated with drugs. SP cells can differentiate into NSP cells, but NSP cells cannot differentiate into SP cells. SP cells had a greater ability to form tumors.

CONCLUSIONThe H446 cell line contained some SP cells with stem cell properties. CD133 and ABCG2 may be cancer stem cell markers of SCLC.

AC133 Antigen ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; Animals ; Antigens, CD ; genetics ; metabolism ; Biomarkers, Tumor ; metabolism ; Cell Differentiation ; Cell Line, Tumor ; Cell Proliferation ; Cell Transformation, Neoplastic ; GTP-Binding Proteins ; genetics ; metabolism ; Glycoproteins ; genetics ; metabolism ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Male ; Mice ; Mice, Nude ; Neoplasm Proteins ; genetics ; metabolism ; Neoplastic Stem Cells ; metabolism ; pathology ; transplantation ; Nuclear Proteins ; genetics ; metabolism ; Peptides ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Side-Population Cells ; metabolism ; pathology ; transplantation ; Small Cell Lung Carcinoma ; metabolism ; pathology