Cancer Stem Cell-like Characteristics Research Articles

Abstract 1851: Estradiol-inducible dependence receptor UNC5a restricts estrogen receptor activity and imparts estradiol dependence to breast cancer cells

Abstract Signaling by Dependence Receptors (DRs) is a new paradigm in cell signaling and recently has been recognized to play a major role in cancers. DRs are cell surface receptors that function as tumor suppressors or induce apoptosis when disengaged from their ligands. In the presence of ligands, these receptors transmit proliferation, migratory, and anti-apoptotic signals thus creating a cellular state that is dependent on ligands for survival. This study was focused on regulation of their expression in breast cancer. We observed that UNC5a, a DR, and its ligand Netrin-1 (NTN1) are estradiol (E2)-inducible depending on cell types. Since E2 and its receptor estrogen receptor alpha (ERα) are major signaling hubs in ERα-positive breast cancers, we examined the function of UNC5a in ERα-positive breast cancer cells. Knockdown of UNC5a resulted in deregulated expression of E2-regulated genes, E2-independent and anti-estrogen-resistant growth in vitro, and E2-indpendent tumor formation in xenograft models. RNA-seq analyses of parental and UNC5a knockdown cells with or without E2 treatment revealed ∼ 10-fold increase in number of E2-regulated genes in UNC5a knockdown cells compared with parental cells. The basal expression of E2-inducible anti-apoptotic BCL-2 was elevated >30-fold at mRNA and/or protein levels in UNC5a knockdown cells compared with vector control cells. In addition, UNC5a knockdown resulted in aberrant NF-κB signaling, which is typically under negative regulation by ERα:E2. Furthermore, UNC5a knockdown cells showed elevated expression of p63, a p53 family transcription factor that promotes breast epithelial stem cell maintenance and basal-like breast cancer. Consistent with the known role of NF-κB and p63 in cancer stem cells, UNC5a-knockdown cells displayed cancer stem cell phenotype as evident from ∼3-fold increase in the number of CD44+/CD24+ and CD44+/EpCAM+ subpopulation compared with parental cells. Overall, our results suggest that E2 induces UNC5a expression as a negative regulatory loop to restrict or fine tune ERα:E2 signaling and maintain luminal phenotype. Loss or mutation of UNC5a, as observed frequently in cancer, could lead to unrestricted E2:ERα signaling and anti-estrogen resistant growth while simultaneously enabling ERα-positive luminal breast cancer cells to acquire basal-like and cancer stem cell-like features. This work is supported by grants from the Susan G. Komen for the Cure (SAC110025 to HN) Citation Format: Poornima Bhat-Nakshatri, Manjushree Anjanappa, Yangyang Hao, Howard Edenberg, Yunlong Liu, Harikrishna Nakshatri. Estradiol-inducible dependence receptor UNC5a restricts estrogen receptor activity and imparts estradiol dependence to breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1851. doi:10.1158/1538-7445.AM2015-1851

TACC3 promotes stemness and is a potential therapeutic target in hepatocellular carcinoma.

Transforming acidic coiled-coil protein 3 (TACC3) is essential for cell mitosis and transcriptional functions. In the present study, we first demonstrated that both TACC3 protein and mRNA levels were elevated in HCC tissue samples compared with non-cancerous tissue biopsies according to western blot analyses, immunohistochemistry (IHC) and quantitative real-time PCR (qRT-PCR) assays. Moreover, high TACC3 expression was positively correlated with poor overall survival (OS) and disease-free survival (DFS) (p < 0.001). Using HCC cell lines, we then demonstrated that either TACC3 knockdown or treatment with the potential TACC3 inhibitor KHS101 suppressed cell growth and sphere formation as well as the expression of stem cell transcription factors, including Bmi1, c-Myc and Nanog. Silencing TACC3 may suppress the Wnt/β-catenin and PI3K/AKT signaling pathways, which regulate cancer stem cell-like characteristics. Taken together, these data suggest that TACC3 is enriched in HCC and that TACC3 down-regulation inhibits the proliferation, clonogenicity, and cancer stem cell-like phenotype of HCC cells. KHS101, a TACC3 inhibitor, may serve as a novel therapeutic agent for HCC patients with tumors characterized by high TACC3 expression.

Exosomal lipids impact on tumoral cell behavior

Exosomal lipids impact on tumoral cell behavior

Aspirin counteracts cancer stem cell features, desmoplasia and gemcitabine resistance in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) is characterized by an extremely poor prognosis. An inflammatory microenvironment triggers the pronounced desmoplasia, the selection of cancer stem-like cells (CSCs) and therapy resistance. The anti-inflammatory drug aspirin is suggested to lower the risk for PDA and to improve the treatment, although available results are conflicting and the effect of aspirin to CSC characteristics and desmoplasia in PDA has not yet been investigated. We characterized the influence of aspirin on CSC features, stromal reactions and gemcitabine resistance. Four established and 3 primary PDA cell lines, non-malignant cells, 3 patient tumor-derived CSC-enriched spheroidal cultures and tissues from patients who did or did not receive aspirin before surgery were analyzed using MTT assays, flow cytometry, colony and spheroid formation assays, Western blot analysis, antibody protein arrays, electrophoretic mobility shift assays (EMSAs), immunohistochemistry and in vivo xenotransplantation. Aspirin significantly induced apoptosis and reduced the viability, self-renewal potential, and expression of proteins involved in inflammation and stem cell signaling. Aspirin also reduced the growth and invasion of tumors in vivo, and it significantly prolonged the survival of mice with orthotopic pancreatic xenografts in combination with gemcitabine. This was associated with a decreased expression of markers for progression, inflammation and desmoplasia. These findings were confirmed in tissue samples obtained from patients who had or had not taken aspirin before surgery. Importantly, aspirin sensitized cells that were resistant to gemcitabine and thereby enhanced the therapeutic efficacy. Aspirin showed no obvious toxic effects on normal cells, chick embryos or mice. These results highlight aspirin as an effective, inexpensive and well-tolerated co-treatment to target inflammation, desmoplasia and CSC features PDA.

Tissue transglutaminase-interleukin-6 axis facilitates peritoneal tumor spreading and metastasis of human ovarian cancer cells.

Inflammation has recently been implicated in cancer formation and progression. As tissue transglutaminase (TG2) has been associated with both inflammatory signaling and tumor cell behavior, we propose that TG2 may be an important link inducing interleukin-6 (IL-6)-mediated cancer cell aggressiveness, including cancer stem cell-like characteristics and distant hematogenous metastasis. We evaluated the effect of differential TG2 and IL-6 expression on in vivo distant metastasis of human ovarian cancer cells. IL-6 production in human ovarian cancer cells was dependent on their TG2 expression levels. The size and efficiency of tumor sphere formation were correlated with TG2 expression levels and were dependent on TG2-mediated IL-6 secretion in human ovarian cancer cells. Primary tumor growth and propagation in the peritoneum and distant hematogenous metastasis into the liver and lung were also dependent on TG2 and downstream IL-6 expression levels in human ovarian cancer cells. In this report, we provide evidence that TG2 is an important link in IL-6-mediated tumor cell aggressiveness, and that TG2 and downstream IL-6 could be important mediators of distant hematogenous metastasis of human ovarian cancer cells. Intervention specific to TG2 and/or downstream IL-6 in ovarian cancer cells could provide a promising means to control tumor metastasis.

Enhanced activation of STAT3 in ascites-derived recurrent ovarian tumors: inhibition of cisplatin-induced STAT3 activation reduced tumorigenicity of ovarian cancer by a loss of cancer stem cell-like characteristics

Chemotherapy resistance is a major obstacle for the treatment of ovarian cancer patients. Combination of drugs which can exert synergistic effect can be a promising strategy to overcome this resistance. In this study, we report significantly enhanced activation of Janus kinase 2 (JAK2) and its downstream target signal transducer and activation of transcription 3 (STAT3) in tumor cells isolated from the ascites of recurrent ovarian cancer patients (CR) compared to tumor cells isolated from the ascites of chemonaive patients (CN). Enhanced activation of JAK2 and STAT3 in the tumor cells of recurrent patients coincided with thein vitroactivation of JAK2 and STAT3 pathway in cisplatin-surviving ovarian cancer cell lines. This coincided with the emergence of cancer stem cell (CSC)-like characteristics in response to cisplatin treatment in ovarian cancer cell lines. Both cisplatin-induced JAK2/STAT3 activation and CSC-like characteristics were inhibited by a low dose JAK2-specific small molecule inhibitor CYT387 in vitro .S ubsequent,in vivo transplantation of cisplatin and CYT387 in vitro treated ovarian cancer cells in mice resulted in a significantly reduced tumor burden compared to that observed in mice injected with cisplatin only-treated cells. In vitro analysis of tumor xenografts at the protein level demonstrated a loss of CSC-like (CD117 and Oct4) and tumorigenic (CA125) markers in cisplatin and CYT387-treated cell-derived xenografts, compared to cisplatin only-treated cell-derived xenografts. These results were consistent with as ignifi cantly reduced activation of JAK2 and STAT3 in cisplatinand CYT387-treated cell-derived xenografts compared to cisplatin only-treated cell derived xenografts. These data suggest that the inhibition of the JAK2/STAT3 pathway by the addition of CYT387 in combination with cisplatin may haveimportant implications for ovarian cancer patients who are treated with platinum-based first line therapies.

MiR-106b modulates cancer stem cell characteristics through TGF-β/Smad signaling in CD44-positive gastric cancer cells

Cancer stem cells have the capacity to form new tumors and are thus considered to be a cause of metastasis and tumor recurrence. However, many of the mechanisms determining cancer stem cell characteristics are still unknown. MicroRNAs (miRNAs) are possible modulators of cancer stem cell generation and may be involved in the retention of cancer stem cell characteristics. The aim of this study was to examine the miRNA expression profiles regulating the cancer stem-like cell characteristics in gastric cancer. We sorted gastric cancer stem-like cells using the stem cell marker CD44 by fluorescence-activated cell sorting. CD44(+) cells formed more and larger spheres compared with CD44(−) cells. Cancer stem cell markers were overexpressed in CD44(+) cells. CD44(+) cells showed increased expression of mesenchymal cell markers, whereas epithelial markers were downregulated. In miRNA microarray, the miR-106b family comprising miR-106b, miR-93, and miR-25 was significantly upregulated in CD44(+) cells than in CD44(−) cells. Smad7, which inhibits transforming growth factor-β (TGF-β)/Smad signaling as a target of the miR-106b family, was downregulated in CD44(+) cells. Furthermore, expression of TGF-β/Smad signal molecules was activated in CD44(+) cells, in accordance with the action of the miR-106b family. Inhibition of miR-106b showed suppression of the TGF-β/Smad signaling pathway and decreased self-renewal capacity and cell invasiveness. Our study suggests that CD44(+) gastric cancer cells show cancer stem cell properties with epithelial–mesenchymal transition (EMT). Increased miR-106b family expression regulated cancer stem-like cell properties, particularly EMT characteristics, through the TGF-β/Smad signaling pathway in CD44(+) stem-like cells. Taken together, these results indicate that targeting miR-106b may be an effective form of cancer therapy in gastric cancer through the modulation of cancer stem cell characteristics.

Claudin-low breast cancers: clinical, pathological, molecular and prognostic characterization.

BackgroundThe lastly identified claudin-low (CL) subtype of breast cancer (BC) remains poorly described as compared to the other molecular subtypes. We provide a comprehensive characterization of the largest series of CL samples reported so far.MethodsFrom a data set of 5447 invasive BC profiled using DNA microarrays, we identified 673 CL samples (12,4%) that we describe comparatively to the other molecular subtypes at several levels: clinicopathological, genomic, transcriptional, survival, and response to chemotherapy.ResultsCL samples display profiles different from other subtypes. For example, they differ from basal tumors regarding the hormone receptor status, with a lower frequency of triple negative (TN) tumors (52% vs 76% for basal cases). Like basal tumors, they show high genomic instability with many gains and losses. At the transcriptional level, CL tumors are the most undifferentiated tumors along the mammary epithelial hierarchy. Compared to basal tumors, they show enrichment for epithelial-to-mesenchymal transition markers, immune response genes, and cancer stem cell–like features, and higher activity of estrogen receptor (ER), progesterone receptor (PR), EGFR, SRC and TGFβ pathways, but lower activity of MYC and PI3K pathways. The 5-year disease-free survival of CL cases (67%) and the rate of pathological complete response (pCR) to primary chemotherapy (32%) are close to those of poor-prognosis and good responder subtypes (basal and ERBB2-enriched). However, the prognostic features of CL tumors are closer to those observed in the whole BC series and in the luminal A subtype, including proliferation-related gene expression signatures (GES). Immunity-related GES valuable in basal breast cancers are not significant in CL tumors. By contrast, the GES predictive for pCR in CL tumors resemble more to those of basal and HER2-enriched tumors than to those of luminal A tumors.ConclusionsMany differences exist between CL and the other subtypes, notably basal. An unexpected finding concerns the relatively high numbers of ER-positive and non-TN tumors within CL subtype, suggesting a larger heterogeneity than in basal and luminal A subtypes.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-13-228) contains supplementary material, which is available to authorized users.

Abstract 2364: Pancreatic cancer stem-like cells display aggressive behavior mediated through the activation of FoxQ1

Abstract Pancreatic cancer (PC) remains as one of the most aggressive and deadly malignant diseases with poorest clinical outcome, and it is the 4th leading cause of cancer-related death in the USA. Higher mortality of patients diagnosed with PC is in part attributed to treatment resistance and early metastatic disease. Sub-populations of cancer cells commonly known as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs) have been identified from most tumors including PC, and the existence of these cells are being recognized to be clinically relevant. Emerging evidence suggests that CSLCs are responsible for many cellular functions including their propensity of increased cell growth/proliferation, migration/invasion, metastasis, and chemo-radio-therapy resistance, all of these attributes lead to poor clinical outcome. However, the pathogenesis and biological significance of CSLCs in PC has not been well characterized. In the present study, we found that triple-marker positive cells (CD44+/CD133+/EpCAM+ cells) cells isolated from human PC cell lines behave like CSCs. These CSLCs exhibit aggressive behavior such as increased cell growth, migration, clonogenicity, and self-renewal capacity. The mRNA expression profiling analysis showed that CSLCs (triple-marker positive cells) exhibit differential expression of more than 1600 mRNAs including Bmi1, BMP4, BST2, BTG1, FOLR1, FoxQ1, PRKAR1A, Sox2, TACSTD2 and Wnt3a, compared to the cells that are triple-marker negative (CD44-/CD133-/EpCAM- cells). The knock-down of FoxQ1 by its siRNA in CSLCs resulted in the inhibition of aggressive behavior, consistent with reduced expression of EpCAM and Snail. These data clearly suggest the role of differentially expressed genes in the regulation of CSLC characteristics, which further suggest that targeting some of these genes in order to eliminate CSLCs could be important for the development of novel therapies for achieving better treatment outcome of patients diagnosed with PC. Citation Format: Bin Bao, Asfar Azmi, Aamir Ahmad, Shadan Ali, Yiwei Li, Fazlul H. Sarkar. Pancreatic cancer stem-like cells display aggressive behavior mediated through the activation of FoxQ1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2364. doi:10.1158/1538-7445.AM2014-2364

Combining targeted drugs to overcome and prevent resistance of solid cancers with some stem-like cell features.

Treatment resistance significantly inhibits the efficiency of targeted cancer therapies in drug-sensitive genotypes. In the current work, we studied mechanisms for rapidly occurring, adaptive resistance in targeted therapy-sensitive lung, breast, and melanoma cancer cell lines. The results show that in ALK translocated lung cancer lines H3122 and H2228, cells with cancer stem-like cell features characterized by high expression of cancer stem cell markers and/or in vivo tumorigenesis can mediate adaptive resistance to oncogene ablative therapy. When pharmacological ablation of ALK oncogene was accompanied with PI3K inhibitor or salinomycin therapy, cancer stem-like cell features were reversed which was accompanied with decreased colony formation. Furthermore, co-targeting was able to block the formation of acquired resistance in H3122 line. The results suggest that cells with cancer stem-like cell features can mediate adaptive resistance to targeted therapies. Since these cells follow the stochastic model, concurrent therapy with an oncogene ablating agent and a stem-like cell-targeting drug is needed for maximal therapeutic efficiency.

CD133-positive cancer stem cells from Colo205 human colon adenocarcinoma cell line show resistance to chemotherapy and display a specific metabolomic profile.

During the past decade, cancer stem-like cells (CSCs) have drawn substantial interest in cancer research since they have been described as major targets to improve treatment of tumors and to prevent recurrence and metastasis. In this paper, we report on the search for CSCs within the Colo205 human adenocarcinoma cell line. We describe that CD133 (prominin) was the only reliable marker for the isolation and characterization of CSCs within a Colo205 cell population. CD133-positive cells displayed many CSC characteristics, such as tumorsphere formation ability, expression of early-stage development markers, high invasiveness, raised tumor initiation potential and resistance to cisplatin chemotherapy treatment. In vitro analyses also highlighted a specific metabolomic profile of CD133-positive cells and we concluded that the chemotherapy resistance of CSCs could be related to the quiescence of such cells associated with their reduced metabolism. Furthermore, in vivo metabolome analyses suggested that a high level of circulating glutathione molecules could also promote treatment resistance. From the perspective of metabolomics, we also discuss the controversial use of serum-free in vitro cultures for CSC enrichment prior to further phenotype characterization.

The Roles of the Epithelial-Mesenchymal Transition Marker PRRX1 and miR-146b-5p in Papillary Thyroid Carcinoma Progression

Thyroid carcinoma is the most common endocrine malignancy, and papillary thyroid carcinoma represents the most common thyroid cancer. Papillary thyroid carcinomas that invade locally or metastasize are associated with a poor prognosis. We found that, during epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1), papillary thyroid carcinoma cells acquired increased cancer stem cell-like features and the transcription factor paired-related homeobox protein 1 (PRRX1; alias PRX-1), a newly identified EMT inducer, was markedly up-regulated. miR-146b-5p was also transiently up-regulated during EMT, and in siRNA experiments miR-146b-5p had an inhibitory role on cell proliferation and invasion during TGF-β1-induced EMT. We conclude that papillary thyroid carcinoma tumor cells exhibit increased cancer stem cell-like features during TGF-β1-induced EMT, that miR-146b-5p has a role in cell proliferation and invasion, and that PRRX1 plays an important role in papillary thyroid carcinoma EMT and disease progression.

Differentially expressed miRNAs in cancer-stem-like cells: markers for tumor cell aggressiveness of pancreatic cancer.

Pancreatic cancer (PC) is one of the most deadly cancers. The higher mortality is in part due to treatment resistance and early onset of metastasis. The existence of cancer-stem-like cells (CSLCs) has been widely accepted to be responsible for tumor aggressiveness in PC. Emerging evidence suggests that CSLCs have the capacity for increased cell growth, cell migration/invasion, metastasis, and treatment resistance, which leads to poor clinical outcome. However, the molecular role of CSLCs in tumor development and progression is poorly understood. Therefore, mechanistic understanding, and targeted killing of CSLCs may provide a newer therapeutic strategy for the treatment of PC. It has been well accepted that microRNAs (miRNAs) play critical roles during tumor development and progression through deregulation of multiple genes. Moreover, deregulated expression of miRNAs may also play a key role in the regulation of CSLC characteristics and functions. Here we show that isolated CD44(+)/CD133(+)/EpCAM(+) cells (triple-marker-positive cells) from human PC cell lines, MiaPaCa-2 and L3.6pl cells, display aggressive characteristics, such as increased cell growth, clonogenicity, cell migration, and self-renewal capacity, which is consistent with overexpression of CSLC signatures/markers. We also found deregulated expression of over 400 miRNAs, including let-7, miR-30, miR-125b, and miR-335, in CSLCs. As a proof-of-concept, knockdown of miR-125b resulted in the inhibition of tumor cell aggressiveness of CSLCs (triple-marker-positive cells), consistent with the downregulation of CD44, EpCAM, EZH2, and snail. These results clearly suggest the importance of miRNAs in the regulation of CSLC characteristics, and may serve as novel targets for therapy.

Inhibition of the JAK2/STAT3 pathway in ovarian cancer results in the loss of cancer stem cell-like characteristics and a reduced tumor burden.

BackgroundCurrent treatment of ovarian cancer patients with chemotherapy leaves behind a residual tumor which results in recurrent ovarian cancer within a short time frame. We have previously demonstrated that a single short-term treatment of ovarian cancer cells with chemotherapy in vitro resulted in a cancer stem cell (CSC)-like enriched residual population which generated significantly greater tumor burden compared to the tumor burden generated by control untreated cells. In this report we looked at the mechanisms of the enrichment of CSC-like residual cells in response to paclitaxel treatment.MethodsThe mechanism of survival of paclitaxel-treated residual cells at a growth inhibitory concentration of 50% (GI50) was determined on isolated tumor cells from the ascites of recurrent ovarian cancer patients and HEY ovarian cancer cell line by in vitro assays and in a mouse xenograft model.ResultsTreatment of isolated tumor cells from the ascites of ovarian cancer patients and HEY ovarian cancer cell line with paclitaxel resulted in a CSC-like residual population which coincided with the activation of Janus activated kinase 2 (JAK2) and signal transducer and activation of transcription 3 (STAT3) pathway in paclitaxel surviving cells. Both paclitaxel-induced JAK2/STAT3 activation and CSC-like characteristics were inhibited by a low dose JAK2-specific small molecule inhibitor CYT387 (1 μM) in vitro. Subsequent, in vivo transplantation of paclitaxel and CYT387-treated HEY cells in mice resulted in a significantly reduced tumor burden compared to that seen with paclitaxel only-treated transplanted cells. In vitro analysis of tumor xenografts at protein and mRNA levels demonstrated a loss of CSC-like markers and CA125 expression in paclitaxel and CYT387-treated cell-derived xenografts, compared to paclitaxel only-treated cell-derived xenografts. These results were consistent with significantly reduced activation of JAK2 and STAT3 in paclitaxel and CYT387-treated cell-derived xenografts compared to paclitaxel only-treated cell derived xenografts.ConclusionsThis proof of principle study demonstrates that inhibition of the JAK2/STAT3 pathway by the addition of CYT387 suppresses the ‘stemness’ profile in chemotherapy-treated residual cells in vitro, which is replicated in vivo, leading to a reduced tumor burden. These findings have important implications for ovarian cancer patients who are treated with taxane and/or platinum-based therapies.

Pancreatic Cancer Stem-like Cells Display Aggressive Behavior Mediated via Activation of FoxQ1

Subpopulations of cancer stem cells (CSCs) or cancer stem-like cells (CSLCs) have been identified from most tumors, including pancreatic cancer (PC), and the existence of these cells is clinically relevant. Emerging evidence suggests that CSLCs participate in cell growth/proliferation, migration/invasion, metastasis, and chemo-radiotherapy resistance, ultimately contributing to poor clinical outcome. However, the pathogenesis and biological significance of CSLCs in PC has not been well characterized. In the present study, we found that isolated triple-marker-positive (CD44(+)/CD133(+)/EpCAM(+)) cells of human PC MiaPaCa-2 and L3.6pl cells behave as CSLCs. These CSLCs exhibit aggressive behavior, such as increased cell growth, migration, clonogenicity, and self-renewal capacity. The mRNA expression profiling analysis showed that CSLCs (CD44(+)/CD133(+)/EpCAM(+)) exhibit differential expression of more than 1,600 mRNAs, including FoxQ1, compared with the triple-marker-negative (CD44(-)/CD133(-)/EpCAM(-)) cells. The knockdown of FoxQ1 by its siRNA in CSLCs resulted in the inhibition of aggressive behavior, consistent with the inhibition of EpCAM and Snail expression. Mouse xenograft tumor studies showed that CSLCs have a 100-fold higher potential for tumor formation and rapid tumor growth, consistent with overexpression of CSC-associated markers/mediators, including FoxQ1, compared with its parental MiaPaCa-2 cells. The inhibition of FoxQ1 attenuated tumor formation and growth, and expression of CSC markers in the xenograft tumor derived from CSLCs of MiaPaCa-2 cells. These data clearly suggest the role of differentially expressed genes in the regulation of CSLC characteristics, further suggesting that targeting some of these genes could be important for the development of novel therapies for achieving better treatment outcome of PC.

The Role of Lipolysis Stimulated Lipoprotein Receptor in Breast Cancer and Directing Breast Cancer Cell Behavior

The claudin-low molecular subtype of breast cancer is of particular interest for clinically the majority of these tumors are poor prognosis, triple negative, invasive ductal carcinomas. Claudin-low tumors are characterized by cancer stem cell-like features and low expression of cell junction and adhesion proteins. Herein, we sought to define the role of lipolysis stimulated lipoprotein receptor (LSR) in breast cancer and cancer cell behavior as LSR was recently correlated with tumor-initiating features. We show that LSR was expressed in epithelium, endothelium, and stromal cells within the healthy breast tissue, as well as in tumor epithelium. In primary breast tumor bioposies, LSR expression was significantly correlated with invasive ductal carcinomas compared to invasive lobular carcinomas, as well as ERα positive tumors and breast cancer cell lines. LSR levels were significantly reduced in claudin-low breast cancer cell lines and functional studies illustrated that re-introduction of LSR into a claudin-low cell line suppressed the EMT phenotype and reduced individual cell migration. However, our data suggest that LSR may promote collective cell migration. Re-introduction of LSR in claudin-low breast cancer cell lines reestablished tight junction protein expression and correlated with transepithelial electrical resistance, thereby reverting claudin-low lines to other intrinsic molecular subtypes. Moreover, overexpression of LSR altered gene expression of pathways involved in transformation and tumorigenesis as well as enhanced proliferation and survival in anchorage independent conditions, highlighting that reestablishment of LSR signaling promotes aggressive/tumor initiating cell behaviors. Collectively, these data highlight a direct role for LSR in driving aggressive breast cancer behavior.

The origin of cancer stem cells

The origin of cancer stem cells

MiR-200a inhibits epithelial-mesenchymal transition of pancreatic cancer stem cell

BackgroundPancreatic cancer is one of the most aggressive cancers, and the aggressiveness of pancreatic cancer is in part due to its intrinsic and extrinsic drug resistance characteristics, which are also associated with the acquisition of epithelial-to-mesenchymal transition (EMT). Increasing evidence suggests that EMT-type cells share many biological characteristics with cancer stem-like cells. And miR-200 has been identified as a powerful regulator of EMT.MethodsCancer Stem Cells (CSCs) of human pancreatic cancer cell line PANC-1 were processed for CD24, CD44 and ESA multi-colorstaining, and sorted out on a BD FACS Aria II machine. RT-qPCR was performed using the miScript PCR Kit to assay the expression of miR-200 family. In order to find the role of miR-200a in the process of EMT, miR-200a mimic was transfected to CSCs.ResultsPancreatic cancer cells with EMT phenotype displayed stem-like cell features characterized by the expression of cell surface markers CD24, CD44 and epithelial-specific antigen (ESA), which was associated with decreased expression of miR-200a. Moreover, overexpression of miR-200a was resulted in down-regulation of N-cadherin, ZEB1 and vimentin, but up-regulation of E-cadherin. In addition, miR-200a overexpression inhibited cell migration and invasion in CSCs.ConclusionIn our study, we found that miR-200a played an important role in linking the characteristics of cancer stem-like cells with EMT-like cell signatures in pancreatic cancer. Selective elimination of cancer stem-like cells by reversing the EMT phenotype to mesenchymal-to-epithelial transition (MET) phenotype using novel agents would be useful for prevention and/or treatment of pancreatic cancer.

Ovarian Cancer Spheroid Cells with Stem Cell-Like Properties Contribute to Tumor Generation, Metastasis and Chemotherapy Resistance through Hypoxia-Resistant Metabolism

Cells with sphere forming capacity, spheroid cells, are present in the malignant ascites of patients with epithelial ovarian cancer (EOC) and represent a significant impediment to efficacious treatment due to their putative role in progression, metastasis and chemotherapy resistance. The exact mechanisms that underlie EOC metastasis and drug resistance are not clear. Understanding the biology of sphere forming cells may contribute to the identification of novel therapeutic opportunities for metastatic EOC. Here we generated spheroid cells from human ovarian cancer cell lines and primary ovarian cancer. Xenoengraftment of as few as 2000 dissociated spheroid cells into immune-deficient mice allowed full recapitulation of the original tumor, whereas >105 parent tumor cells remained non-tumorigenic. The spheroid cells were found to be enriched for cells with cancer stem cell-like characteristics such as upregulation of stem cell genes, self-renewal, high proliferative and differentiation potential, and high aldehyde dehydrogenase (ALDH) activity. Furthermore, spheroid cells were more aggressive in growth, migration, invasion, scratch recovery, clonogenic survival, anchorage-independent growth, and more resistant to chemotherapy in vitro. 13C-glucose metabolic studies revealed that spheroid cells route glucose predominantly to anaerobic glycolysis and pentose cycle to the detriment of re-routing glucose for anabolic purposes. These metabolic properties of sphere forming cells appear to confer increased resistance to apoptosis and contribute to more aggressive tumor growth. Collectively, we demonstrated that spheroid cells with cancer stem cell-like characteristics contributed to tumor generation, progression and chemotherapy resistance. This study provides insight into the relationship between tumor dissemination and metabolic attributes of human cancer stem cells and has clinical implications for cancer therapy.

MiR-203 Inhibits the Proliferation and Self-Renewal of Esophageal Cancer Stem-Like Cells by Suppressing Stem Renewal Factor Bmi-1

Cancer stem-like cells exist in many malignancies and several stem cell-related genes and microRNAs, such as Bmi-1 and miR-203, have been identified as cancer stem-like cell regulators using gene microarray or sequencing analysis. Previously, we used side population (SP) sorting to enrich cancer stem-like cells from esophageal squamous cell carcinoma (ESCC) cell line EC9706. Our results demonstrated that EC9706 SP cells shared common features of cancer stem-like cells. In this study, we examined the expression of Bmi-1 and miR-203 in ESCC SP and non-SP (NSP) cells. Our results showed that, when compared with NSP cells, Bmi-1 was up-regulated and miR-203 was down-regulated in SP cells. During the differentiation from SP to NSP cells, the expression levels of Bmi-1 were gradually decreased. Overexpression of miR-203 resulted in a significant reduction of endogenous Bmi-1 protein level in EC9706 cells. SP and NSP analyses revealed that the SP cell fraction was markedly decreased in miR-203 overexpressed cells. miR-203 overexpressed cells also showed a significant reduction in colony formation, which was resistant to chemotherapeutic drug treatment and tumorigenicity in nude mice. Rescue experiments demonstrated that ectopic expression of Bmi-1 in miR-203 overexpressed cells increased the SP fraction and restored cell proliferation. Taken together, these results indicated that stem renewal factor Bmi-1 was a direct target of miR-203. The regulation of Bmi-1 by miR-203 may play an important role in controlling cell proliferation and self-renewal of esophageal cancer stem-like cells. It may also promote the development of new therapeutic strategies and efficient drugs that target ESCC stem-like cells.