Detection of tumor stem cell markers in pancreatic carcinoma cell lines

BACKGROUND: Cancer of the pancreas is the fourth leading cause of cancer death in industrialized countries. In malignancy, actively proliferating cells may be effectively targeted and killed by anti-cancer therapies, but stem cells may survive and support re-growth of the tumor. Thus, new strategies for the treatment of cancer clearly will also have to target cancer stem cells. The goal of the present study was to determine whether pancreatic carcinoma cell growth may be driven by a subpopulation of cancer stem cells. Because previous data implicated ABCG2 and CD133 as stem cell markers in hematopoietic and neural stem/progenitor cells, we analyzed the expression of these two proteins in pancreatic carcinoma cell lines. METHODS: Five established pancreatic adenocarcinoma cell lines were analyzed. Total RNA was isolated and real- time RT-PCR was performed to determine the expression of ABCG2 and CD133. Surface expression of ABCG2 and CD133 was analyzed by flow cytometric analysis. RESULTS: All pancreatic carcinoma cell lines tested expressed significantly higher levels of ABCG2 than non-malignant fibroblasts or two other malignant non- pancreatic cell lines, i.e., SaOS2 osteosarcoma and SKOV3 ovarian cancer. Elevated CD133 expression was found in two out of five pancreatic carcinoma cell lines tested. Using flow cytometric analysis we confirmed surface expression of ABCG2 in all five lines. Yet, CD133 surface expression was detectable in the two cell lines, A818-6 and PancTu1, which exhibited higher mRNA levels.CONCLUSIONS: Two stem cell markers, ABCG2 and CD133 are expressed in pancreatic carcinoma cell lines. ABCG2 and/or CD133 positive cells may represent subpopulation of putative cancer stem cells also in this malignancy. Because cancer stem cells are thought to be responsible for tumor initiation and its recurrence after an initial response to chemotherapy, they may be a very promising target for new drug developments.

Liver cancer stem cell markers: Progression and therapeutic implications

Cancer stem cells(CSCs) are a small subpopulation in cancer, have been proposed to be cancer-initiating cells, and have been shown to be responsible for chemotherapy resistance and cancer recurrence. The identification of CSC subpopulations inside a tumor presents a new understanding of cancer development because it implies that tumors can only be eradicated by targeting CSCs. Although advances in liver cancer detection and treatment have increased the possibility of curing the disease at early stages, unfortunately, most patients will relapse and succumb to their disease. Strategies aimed at efficiently targeting liver CSCs are becoming important for monitoring the progress of liver cancer therapy and for evaluating new therapeutic approaches. Herein, we provide a critical discussion of biological markers described in the literature regarding liver cancer stem cells and the potential of these markers to serve as therapeutic targets.

Expression Compilation of Several Putative Cancer Stem Cell Markers by Primary Ovarian Carcinoma

Cancer stem cells (CSCs) or tumor initiating cells are rare cells that are able to establish a tumor or metastasis. Identification of those CSCs is, however, cumbersome even in established cell lines. Several cancer stem cell markers were reported to be expressed by ovarian cancer. Those cancer stem cells are gifted with lower vulnerability to irradiation and cytostatic drugs explaining the high incidence of recurrence after treatment. A variety of different cancer stem cell markers were described for epithelial tumors. Also, cancer cell lines were assessed for stem cell markers with no common denominator. The expression of CD24, CD44, CD117, CD133, ABCG2, ALDH was determined for cells from 22 patients. Ovarian cancer cells were collected from ascites. Part of the tumor cells were analyzed immediately and stained for the above mentioned cancer stem cell markers. The remainder of the cells was cultured for several weeks using standard stem cell culture conditions. We observed a large variety in expression of putative stem cell markers for primary tumors. After two weeks of culture spheres were seen in several cultures, indicative for cancer stem cells, though not all patients’ cells were able to form spheres. Our data show for the first time the heterogeneity in marker display in primary tumors. Also for the cultured cells stem cell markers were determined. None of the stem cell markers was expressed by all patients’ cells. No correlation with tumor type was demonstrated. The complexity of expression challenges the isolation of cancer stem

Ardisia gigantifolia ethanolic extract inhibits cell proliferation and targets cancer stem cells in gastric cancer

Objective:To evaluate the effects of ethanol extract from Ardisia gigantifolia leaves on cell proliferation and cancer stem cell(CSC)number in gastric cancer.Methods:The inhibitory effect of Ardisia gigantifolia extract on the proliferation of MKN45 and MKN74 gastric cancer cells was assessed using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay.Non-adherent culture(3D)model was used to evaluate the effect of the extract on tumorsphere size and number.Moreover,the expression of CD44,ALDH,and p21 was determined by immunofluorescence analysis.Flow cytometric analysis was performed to evaluate cell cycle arrest and the expression of gastric CSC markers CD44 and ALDH.Real-time PCR analysis was also carried out to assess the effect of the extract on the expression of cell cycle-regulated genes.Results:Ardisia gigantifolia extract effectively inhibited cell proliferation with an IC_(50)of 55.7μg/m L in MKN45 cells and 123.6μg/m L in MKN74 cells.The extract also arrested cell cycle in the G_(0)/G_(1)phase as well as significantly reduced the size and number of tumorspheres.The markedly increased expression of p21 was observed at both m RNA and protein levels in the extract-treated adherent cells and tumorspheres.In addition,Ardisia gigantifolia extract significantly reduced the number of CD44-and/or ALDH-expressing gastric CSC.Conclusions:The development of gastric CSC can be inhibited by the ethanol extract of Ardisia gigantifolia.

Tissue-specific cancer stem/progenitor cells:Therapeutic implications

Surgical resection,chemotherapy,and radiation are the standard therapeutic modalities for treating cancer.These approaches are intended to target the more mature and rapidly dividing cancer cells.However,they spare the relatively quiescent and intrinsically resistant cancer stem cells(CSCs)subpopulation residing within the tumor tissue.Thus,a temporary eradication is achieved and the tumor bulk tends to revert supported by CSCs'resistant features.Based on their unique expression profile,the identification,isolation,and selective targeting of CSCs hold great promise for challenging treatment failure and reducing the risk of cancer recurrence.Yet,targeting CSCs is limited mainly by the irrelevance of the utilized cancer models.A new era of targeted and personalized anti-cancer therapies has been developed with cancer patient-derived organoids(PDOs)as a tool for establishing pre-clinical tumor models.Herein,we discuss the updated and presently available tissue-specific CSC markers in five highly occurring solid tumors.Additionally,we highlight the advantage and relevance of the threedimensional PDOs culture model as a platform for modeling cancer,evaluating the efficacy of CSC-based therapeutics,and predicting drug response in cancer patients.

Comparison of phenotypic markers and neural differentiation potential of multipotent adult progenitor cells and mesenchymal stem cells

AIM: To compare the phenotypic and neural differentiation potential of human bone marrow derived multipotent adult progenitor cells (MAPC) and mesenchymal stem cells (MSC). METHODS: Cultures of MAPC and MSC were established in parallel from same samples of human bone marrow (n = 5). Both stem cell types were evaluated for expression of pluripotency markers including Oct-4 and Nanog by immunocytochemistry and reversetranscription polymerase chain reaction (RT-PCR) and expression of standard mesenchymal markers including CD14, CD34, CD44, CD45, CD73, CD90, CD105 andhuman leukocyte antigen (HLA)-ABC by flow cytometry. After treatment with neural induction medium both MAPC and MSC were evaluated for expression of neural proteins [neuronal filament-200 (NF-200) and glial fibrillar acidic protein (GFAP)] by immunocytochemistry and Western blotting and neural genes [NF-200, GFAP, Tau, microtubule-associated protein (MAP)-1B, MAP-2, neuron-specific enolase (NSE) and oligodendrocyte-1 (Olig-1)] by quantitative real-time-PCR. RESULTS: MAPC had small trigonal shaped while MSC had elongated spindle-shaped morphology. The MAPC expressed Oct-4 and Nanog both at gene and protein levels, whereas MSC were negative for these pluripotent markers. MAPC were negative for HLA-ABC while MSC had high expression of HLA-ABC. In addition, MAPC as compared to MSC had significantly lower expression of CD44 (36.56% ± 1.92% vs 98.23% ± 0.51%), CD73 (15.11% ± 2.24% vs 98.53% ± 2.22%) and CD105 (13.81% ± 3.82%vs 95.12% ± 5.65%) (P < 0.001, for all) MAPC cultures compared to MSC cultures treated with neural induction medium had significantly higher fold change expression of NF-200 (0.64), GFAP (0.52), Tau (0.59), MAP-2 (0.72), Olig-1 (0.18) and NSE (0.29) proteins (P < 0.01 for Olig-1 and P < 0.001 for rest) as well as higher fold change expression of genes of NF-200 (1.34),GFAP (1.12),Tau (1.08),MAP-1B (0.92), MAP-2 (1.14) andNSE (0.4) (P < 0.001 for all). CONCLUSION: MAPC can be differentially characterized from MSC as Oct-4 and Nanog positive stem cells with no expression of HLA-ABC and low expression of mesenchymal markers CD44, CD73 and CD105 and when compared to MSC they possess greater predilection for differentiation into neuro-ectodermal lineage.

Characterization of the osteogenic potential of mesenchymal stem cells from human periodontal ligament based on cell surface markers

Mesenchymal stem cell （MSC）-mediated therapy has been shown to be clinically effective in regenerating tissue defects. For improved regenerative therapy, it is critical to isolate homogenous populations of MSCs with high capacity to differentiate into appropriate tissues. The utilization of stem cell surface antigens provides a means to identify MSCs from various tissues. However, few surface markers that consistently isolate highly regenerative MSCs have been validated, making it challenging for routine clinical applications and making it all the more imperative to identify reliable surface markers. In this study, we used three surface marker combinations： CD51/CD140a, CD271, and STRO-1/CD146 for the isolation of homogenous populations of dental mesenchymal stem cells （DMSCs） from heterogeneous periodontal ligament cells （PDLCs）. Fluorescence-activated cell sorting analysis revealed that 24% of PDLCs were CD51＋/CD140a＋, 0.8% were CD271＋, and 2.4% were STRO-1＋/CD146＋. Sorted cell populations were further assessed for their multipotent properties by inducing osteogenic and chondrogenic differentiation. All three subsets of isolated DMSCs exhibited differentiation capacity into osteogenic and chondrogenic lineages but with varying degrees. CD271＋ DMSCs demonstrated the greatest osteogenic potential with strong induction of osteogenic markers such as DLX5, RUNX2, and BGLAP. Our study provides evidence that surface marker combinations used in this study are sufficient markers for the isolation of DMSCs from PDLCs. These results provide important insight into using specific surface markers for identifying homogenous populations of DMSCs for their improved utilization in regenerative medicine.

Single CD271 marker isolates mesenchymal stem cells from human dental pulp

Mesenchymal stem cells （MSCs） are a promising tool in regenerative medicine due to their capacity to differentiate into multiple lineages. In addition to MSCs isolated from bone marrow （BMSCs）, adult MSCs are isolated from craniofacial tissues including dental pulp tissues （DPs） using various stem cell surface markers. However, there has been a lack of consensus on a set of surface makers that are reproducibly effective at isolating putative multipotent dental mesenchymal stem cel^s （~M^Cs）. II1 ~his stucly, we used clif^et（~nt combinations of surface markers （CD51/CD140a, CD271, and STRO-1/CD146） to isolate homogeneous populations of DMSCs from heterogeneous dental pulp cells （DPCs） obtained from DP and compared their capacity to undergo multilineage differentiation. Fluorescence-activated cell sorting revealed that 27.3% of DPCs were CD51＋/CD140a＋, 10.6% were CD271＋, and 0.3% were STRO-1＋/CD146＋. Under odontogenic conditions, all three subsets of isolated DMSCs exhibited differentiation capacity into odontogenic lineages. Among these isolated subsets of DMSCs, CD271＋ DMSCs demonstrated the greatest odontogenic potential. While all three combinations of surface markers in this study successfully isolated DMSCs from DPCs, the single CD271 marker presents the most effective stem cell surface marker for identification of DMSCs with high odontogenic potential. Isolated CD271＋ DMSCs could potentially be utilized for future clinical applications in dentistry and regenerative medicine.

Fetal cardiac mesenchymal stem cells express embryonal markers and exhibit differentiation into cells of all three germ layers

AIM:To study the expression of embryonal markers by fetal cardiac mesenchymal stem cells(fC-MSC)and their differentiation into cells of all the germ layers. METHODS:Ten independent cultures of rat fCMSC were set up from cells derived from individual or pooled fetal hearts and studies given below were carried out at passages 3,6,15 and 21.The phenotypic markers CD29,CD31,CD34,CD45,CD73,CD90, CD105,CD166 and HLA-DR were analyzed by flow cytometry.The expression of embryonal markers Oct-4, Nanog,Sox-2,SSEA-1,SSEA-3,SSEA-4,TRA-1-60 and TRA 1-81 were studied by immunocytochemistry.The fC-MSC treated with specific induction medium were evaluated for their differentiation into(1)adipocytes and osteocytes(mesodermal cells)by Oil Red O and Alizarin Red staining,respectively,as well as by expression of lipoprotein lipase,PPARγ2 genes in adipocytes and osteopontin and RUNX2 genes in osteocytes by reverse-transcription polymerase chain reaction(RT- PCR);(2)neuronal(ectodermal)cells by expression of neuronal Filament-160 and Glial Fibrillar Acidic Protein by RT-PCR and immunocytochemistry;and(3)hepa- tocytic(endodermal)cells by expression of albumin by RT-PCR and immunocytochemistry,glycogen deposits by Periodic Acid Schiff staining and excretion of urea into the culture supernatant. RESULTS:The fC-MSC expressed CD29,CD73,CD90, CD105,CD166 but lacked expression of CD31,CD34, CD45 and HLA-DR.They expressed embryonal markers,viz.Oct-4,Nanog,Sox-2,SSEA-1,SSEA-3,SSEA-4, TRA-1-81 but not TRA-1-60.On treatment with specific induction media,they differentiated into adipocytes and osteocytes,neuronal cells and hepatocytic cells. CONCLUSION:Our results together suggest that fCMSC are primitive stem cell types with a high degree of plasticity and,in addition to their suitability for cardiovascular regenerative therapy,they may have a wide spectrum of therapeutic applications in regenerative medicine.

Doublecortin-like kinase 1 exhibits cancer stem cell-like characteristics in a human colon cancer cell line

Objective： Colon cancer stem cells （CSCs） are implicated in colorectal cancer carcinogenesis, metastasis, and therapeutic resistance. The identification of these cells could help to develop novel therapeutic strategies. Doublecortin-like kinase 1 （DCLK1） has been viewed as a marker for gastrointestinal stem cells that fuel the self-renewal process, however others view them as a marker of Tuft cells or as an enteroendocrine subtype. The purpose of this study was to use a colon cancer cell line to identify and characterize the stem-like characteristics of the DCLKI＋ cell population. Methods： To enrich stem-like cells, HCT116 cells （derived from colon adenocarcinomas） were cultured using serum-free media to form spheres under both normal oxygen and hypoxia condition. DCLK1 transcript expression in the adherent parental cells and spheroids was quantified using quantitative real time reverse transcription- polymerase chain reaction [（q）RT-PCR]. DCLK1 protein expression was determined using flow cytometry. Self-renewal capability from adherent parental cells and spheroids was determined using extreme limiting dilution analysis （ELDA）. Results： Under both normal oxygen and hypoxia condition, the adherent parental cells were composed of cells that express low levels of DCLK1. However, spheroids exhibited an increased frequency of cells expressing DCLK1 on both mRNA and protein levels. Cells derived from spheroids also possess stronger self-renewal capability. Conclusions： The higher fraction of DCLK1 ＋ cells exhibited by spheroids and hypoxia reflects the stem- like characteristics of these cells. DCLK1 may represent an ideal marker to study and develop effective strategies to overcome chemo-resistance and relapse of colon cancer.

ABC transporters,neural stem cells and neurogenesis - a different perspective

Stem cells intrigue. They have the ability to divide exponentially, recreate the stem cell compartment, as well as create differentiated cells to generate tissues. Therefore, they should be natural candidates to provide a renewable source of cells for transplantation applied in regenerative medicine. Stem cells have the capacity to generate specific tissues or even whole organs like the blood, heart, or bones. A subgroup of stem cells, the neural stem cells （NSCs）, is characterized as a self-renewing population that generates neurons and glia of the developing brain. They can be isolated, genetically manipulated and differentiated in vitro and reintroduced into a developing, adult or a pathologically altered central nervous system. NSCs have been considered for use in cell replacement therapies in various neurodegenerative diseases such as Parkinson＇s disease and Alzheimer＇s disease. Characterization of genes with tightly controlled expression patterns during differentiation represents an approach to understanding the regulation of stem cell commitment. The regulation of stem cell biology by the ATP-binding cassette （ABC） transporters has emerged as an important new field of investigation. As a major focus of stem cell research is in the manipulation of cells to enable differentiation into a targeted cell population; in this review, we discuss recent literatures on ABC transporters and stem cells, and propose an integrated view on the role of the ABC transporters, especially ABCA2, ABCA3, ABCB 1 and ABCG2, in NSCs＇ proliferation, differentiation and regulation, along with comparisons to that in hematopoietic and other stem cells.

Methods to produce induced pluripotent stem cell-derived mesenchymal stem cells: Mesenchymal stem cells from induced pluripotent stem cells

Mesenchymal stem cells(MSCs)have received significant attention in recent years due to their large potential for cell therapy.Indeed,they secrete a wide variety of immunomodulatory factors of interest for the treatment of immune-related disorders and inflammatory diseases.MSCs can be extracted from multiple tissues of the human body.However,several factors may restrict their use for clinical applications:the requirement of invasive procedures for their isolation,their limited numbers,and their heterogeneity according to the tissue of origin or donor.In addition,MSCs often present early signs of replicative senescence limiting their expansion in vitro,and their therapeutic capacity in vivo.Due to the clinical potential of MSCs,a considerable number of methods to differentiate induced pluripotent stem cells(iPSCs)into MSCs have emerged.iPSCs represent a new reliable,unlimited source to generate MSCs(MSCs derived from iPSC,iMSCs)from homogeneous and well-characterized cell lines,which would relieve many of the above mentioned technical and biological limitations.Additionally,the use of iPSCs prevents some of the ethical concerns surrounding the use of human embryonic stem cells.In this review,we analyze the main current protocols used to differentiate human iPSCs into MSCs,which we classify into five different categories:MSC Switch,Embryoid Body Formation,Specific Differentiation,Pathway Inhibitor,and Platelet Lysate.We also evaluate common and method-specific culture components and provide a list of positive and negative markers for MSC characterization.Further guidance on material requirements to produce iMSCs with these methods and on the phenotypic features of the iMSCs obtained is added.The information may help researchers identify protocol options to design and/or refine standardized procedures for large-scale production of iMSCs fitting clinical demands.

Human dental pulp stem cells express many pluripotency regulators and differentiate into neuronal cells

Stem cells were isolated from human dental pulp using an optimized method, in which pulp pieces were digested by enzymes and immobilized to enhance cell outgrowth. Stem cell marker expression was detected by reverse transcription-PCR （RT-PCR）, and differentiation markers were detected by real-time quantitative RT-PCR and immunocytochemistry. Results showed that dental pulp stem cells actively expressed nanog, oct4, nucleostemin slain-l, jmjdla, jmjd2c, and cyclin DI. When stem cells were induced to differentiate into neurons, nucleostemin, nanog, and cyclin D1 expression significantly decreased, whereas expression of neuronal markers, such as microtubule associated protein-2 and neurofilament-heavy, significantly increased. These results suggested that stem cells exited a pluripotent state and entered a neuronal differentiation pathway. In addition, results demonstrated that human dental pulp serves as a reservoir of stem cells that express defined stem cell markers; these cells were easily isolated and were induced to differentiate towards a desired cell lineage.

Biliary tract cancer stem cells-translational options and challenges

Management of biliary tract cancer remains challenging. Tumors show high recurrence rates and therapeutic resistance, leading to dismal prognosis and short survival. The cancer stem cell model states that a tumor is a heterogeneous conglomerate of cells, in which a certain subpopulation of cells-the cancer stem cells-possesses stem cell properties. Cancer stem cells have high clinical relevance due to their potential contributions to development, progression and aggressiveness as well as recurrence and metastasis of malignant tumors. Consequently, reliable identification of as well as pharmacological intervention with cancer stem cells is an intensively investigated and promising research field. The involvement of cancer stem cells in biliary tract cancer is likely as a number of studies demonstrated their existence and the obvious clinical relevance of several established cancer stem cell markers in biliary tract cancer models and tissues. In the present article, we review and discuss the currently available literature addressing the role of putative cancer stem cells in biliary tract cancer as well as the connection between known contributors of biliary tract tumorigenesis such as oncogenic signaling pathways, micro-RNAs and the tumor microenvironment with cancer stem cells.

Human dental pulp stem cells: Applications in future regenerative medicine

Stem cells are pluripotent cells, having a property of differentiating into various types of cells of human body. Several studies have developed mesenchymal stem cells(MSCs) from various human tissues,peripheral blood and body fluids. These cells are then characterized by cellular and molecular markers to understand their specific phenotypes. Dental pulp stem cells(DPSCs) are having a MSCs phenotype and they are differentiated into neuron, cardiomyocytes, chondrocytes, osteoblasts, liver cells and β cells of islet of pancreas. Thus, DPSCs have shown great potentiality to use in regenerative medicine for treatment of various human diseases including dental related problems. These cells can also be developed into induced pluripotent stem cells by incorporation of pluripotency markers and use for regenerative therapies of various diseases. The DPSCs are derived from various dental tissues such as human exfoliated deciduous teeth, apical papilla, periodontal ligament and dental follicle tissue. This review will overview the information about isolation, cellular and molecular characterization and differentiation of DPSCs into various types of human cells and thus these cells have important applications in regenerative therapies for various diseases. This review will be most useful for postgraduate dental students as well as scientists working in the field of oral pathology and oral medicine.

Reporter gene systems for the identification and characterization of cancer stem cells

Cancer stem cells(CSCs)are tumor cells that share functional characteristics with normal and embryonic stem cells.CSCs have increased tumor-initiating capacity and metastatic potential and lower sensitivity to chemo-and radiotherapy,with important roles in tumor progression and the response to therapy.Thus,a current goal of cancer research is to eliminate CSCs,necessitating an adequate phenotypic and functional characterization of CSCs.Strategies have been developed to identify,enrich,and track CSCs,many of which distinguish CSCs by evaluating the expression of surface markers,the initiation of specific signaling pathways,and the activation of master transcription factors that control stemness in normal cells.We review and discuss the use of reporter gene systems for identifying CSCs.Reporters that are under the control of aldehyde dehydrogenase 1A1,CD133,Notch,Nanog homeobox,Sex-determining region Y-box 2,and POU class 5 homeobox can be used to identify CSCs in many tumor types,track cells in real time,and screen for drugs.Thus,reporter gene systems,in combination with in vitro and in vivo functional assays,can assess changes in the CSCs pool.We present relevant examples of these systems in the evaluation of experimental CSCs-targeting therapeutics,demonstrating their value in CSCs research.

An overview of the role of cancer stem cells in spine tumors with a special focus on chordoma

Primary malignant tumors of the spine are relatively rare, less than 5% of all spinal column tumors. However, these lesions are often among the most difficult to treat and encompass challenging pathologies such as chordoma and a variety of invasive sarcomas. The mechanisms of tumor recurrence after surgical intervention, as well as resistance to radiation and chemotherapy, remain a pervasive and costly problem. Recent evidence has emerged supporting the hypothesis that solid tumors contain a sub-population of cancer cells that possess characteristics normally associated with stem cells. Particularly, the potential for long-term proliferation appears to be restricted to subpopulations of cancer stem cells(CSCs) functionally defined by their capacity to self-renew and give rise to differentiated cells that phenotypically recapitulate the original tumor, thereby causing relapse and patient death. These cancer stem cells present a unique opportunity to better understand the biology of solid tumors in general, as well as targets for future therapeutics. The general objective of the current study is to discuss the fundamental concepts for understanding the role of CSCs with respect to chemoresistance, radioresistance, special cell surface markers, cancer recurrence and metastasis intumors of the osseous spine. This discussion is followed by a specific review of what is known about the role of CSCs in chordoma, the most common primary malignant osseous tumor of the spine.

Murine models based on acute myeloid leukemia-initiating stem cells xenografting

Acute myeloid leukemia(AML) is an aggressive malignant disease defined by abnormal expansion of myeloid blasts. Despite recent advances in understanding AML pathogenesis and identifying their molecular subtypes based on somatic mutations, AML is still characterized by poor outcomes, with a 5-year survival rate of only 30%-40%, the majority of the patients dying due to AML relapse. Leukemia stem cells(LSC) are considered to be at the root of chemotherapeutic resistance and AML relapse. Although numerous studies have tried to better characterize LSCs in terms of surface and molecular markers, a specific marker of LSC has not been found, and still the most universally accepted phenotypic signature remains the surface antigens CD34+CD38- that is shared with normal hematopoietic stem cells. Animal models provides the means to investigate the factors responsible for leukemic transformation, the intrinsic differences between secondary post-myeloproliferative neoplasm AML and de novo AML, especially the signaling pathways involved in inflammation and hematopoiesis. However, AML proved to be one of the hematological malignancies that is difficult to engraft even in the most immunodeficient mice strains, and numerous ongoing attempts are focused to develop "humanized mice" that can support the engraftment of LSC. This present review is aiming to in-troduce the field of AML pathogenesis and the concept of LSC, to present the current knowledge on leukemic blasts surface markers and recent attempts to develop best AML animal models.

Generation of a human embryonic stem cell line stably expressing high levels of the fluorescent protein mCherry

AIM:The generation and characterization of a human embryonic stem cell (hESC) line stably expressing red fluorescent mCherry protein. METHODS:Lentiviral transduction of a ubiquitously-expressed human EF-1α promoter driven mCherry transgene was performed in MEL2 hESC. Red fluore-scence was assessed by immunofluorescence and flow cytometry. Pluripotency of stably transduced hESC was determined by immunofluorescent pluripotency marker expression, flow cytometry, teratoma assays andembryoid body-based differentiation followed by reverse transcriptase-polymerase chain reaction. Quantification of cell motility and survival was performed with time lapse microscopy. RESULTS:Constitutively fluorescently-labeled hESCs are useful tools for facile in vitro and in vivo tracking of survival, motility and cell spreading on various surfaces before and after differentiation. Here we describe the generation and characterization of a hESC line (MEL2) stably expressing red fluorescent protein, mCherry. This line was generated by random integration of a fluorescent protein-expressing cassette, driven by the ubiquitously-expressed human EF-1α promoter. Stably transfected MEL2-mCherry hESC were shown to express pluripo-tency markers in the nucleus (POU5F1/OCT4, NANOG and SOX2) and on the cell surface (SSEA4, TRA1-60 and TG30/CD9) and were shown to maintain a normal karyotype in long-term (for at least 35 passages) culture. MEL2-mCherry hESC further readily differentiated into representative cell types of the three germ layers in embryoid body and teratoma based assays and, importantly, maintained robust mCherry expression throughout differentiation. The cell line was next adapted to singlecell passaging, rendering it compatible with numerous bioengineering applications such as measurement of cell motility and cell spreading on various protein modified surfaces, quantification of cell attachment to nanoparticles and rapid estimation of cell survival. CONCLUSION:The MEL2-mCherry hESC line conforms to the criteria of bona fide pluripotent stem cells and maintains red fluorescence throughout differentiation, making it a useful tool for bioengineering and in vivo tracking experiments.

Establishment and molecular characterization of breast cancer mesenchymal stem cell line derived from human non-metastasis breast cancer tumor

Breast cancer remains a leading cause of morbidity and mortality in women mainly because of the propensity of primary breast tumors to metastasize. It is composed of heterogeneous cell populations with different biological properties. Breast cancer-initiating cells have been recently identified in breast carcinoma as CD44+/CD24-/low cells, which display stem cell like properties. In the present study, we have isolated breast cancer stem cells from non-metastasis tumor tissue, which is presently at passage 18 and designated as human Breast Cancer Mesenchymal Stem Cells (hBCMSCs) line. These cells showed spindle shaped morphology and formed mammos-pheres as well as pluripotency clones indicating their stem cell nature. Molecular marker study confirmed mesenchymal nature as well as pluripotency, plasticity and oncogenicity of these cells. The hBCMSCs cell line may likely contain a heterogeneous population of malignant cells. Interestingly, we also found that these cells exhibit BRCA 2 mutation, which was found in Indian population. Overall, this study revealed that hBCMSCs cell line may represent a suitable in vitro model to study the mechanism of breast cancer which further leads to an identification of molecular targets for future breast cancer targeted therapy.