Expectation of success following noncontingent punishment in introverts and extraverts

Ciprofloxacin Improves the Stemness of Human Dermal Papilla Cells

Improvement in the expansion method of adult stem cells may augment their use in regenerative therapy. Using human dermal papilla cell line as well as primary dermal papilla cells as model systems, the present study demonstrated that ciprofloxacin treatment could prevent the loss of stemness during culture. Clonogenicity and stem cell markers of dermal papilla cells were shown to gradually decrease in the culture in a time-dependent manner. Treatment of the cells with nontoxic concentrations of ciprofloxacin could maintain both stem cell morphology and clonogenicity, as well as all stem cells markers. We found that ciprofloxacin exerted its effect through ATP-dependent tyrosine kinase/glycogen synthase kinase3β dependent mechanism which in turn upregulated β-catenin. Besides, ciprofloxacin was shown to induce epithelial-mesenchymal transition in DPCs as the transcription factors ZEB1 and Snail were significantly increased. Furthermore, the self-renewal proteins of Wnt/β-catenin pathway, namely, Nanog and Oct-4 were significantly upregulated in the ciprofloxacin-treated cells. The effects of ciprofloxacin in preserving stem cell features were confirmed in the primary dermal papilla cells directly obtained from human hair follicles. Together, these results revealed a novel application of ciprofloxacin for stem cell maintenance and provided the underlying mechanisms that are responsible for the stemness in dermal papilla cells.

Intragenic G-quadruplex structure formed in the human CD133 and its biological and translational relevance

Cancer stem cells (CSCs) have been identified in several solid malignancies and are now emerging as a plausible target for drug discovery. Beside the questionable existence of CSCs specific markers, the expression of CD133 was reported to be responsible for conferring CSC aggressiveness. Here, we identified two G-rich sequences localized within the introns 3 and 7 of the CD133 gene able to form G-quadruplex (G4) structures, bound and stabilized by small molecules. We further showed that treatment of patient-derived colon CSCs with G4-interacting agents triggers alternative splicing that dramatically impairs the expression of CD133. Interestingly, this is strongly associated with a loss of CSC properties, including self-renewing, motility, tumor initiation and metastases dissemination. Notably, the effects of G4 stabilization on some of these CSC properties are uncoupled from DNA damage response and are fully recapitulated by the selective interference of the CD133 expression.In conclusion, we provided the first proof of the existence of G4 structures within the CD133 gene that can be pharmacologically targeted to impair CSC aggressiveness. This discloses a class of potential antitumoral agents capable of targeting the CSC subpopulation within the tumoral bulk.

NLK functions to maintain proliferation and stemness of NSCLC and is a target of metformin

Objective

Nemo-like kinase (NLK) is an evolutionarily conserved serine/threonine kinase that regulates the activity of a wide range of signal transduction pathways. Metformin, an oral antidiabetic drug, is used for cancer prevention. However, the significance and underlying mechanism of NLK and metformin in oncogenesis has not been fully elucidated. Here, we investigate a novel role of NLK and metformin in human non-small cell lung cancer (NSCLC).

Materials and methods

NLK expression was analyzed in 121 NSCLCs and 92 normal lung tissue samples from benign pulmonary disease. Lentivirus vectors with NLK-shRNA were used to examine the effect of NLK on cell proliferation and tumorigenesis in vitro. Then, tumor xenograft mouse models revealed that NLK knockdown cells had a reduced ability for tumor formation compared with the control group in vivo. Multiple cell cycle regulator expression patterns induced by NLK silencing were examined by western blots in A549 cells. We also employed metformin to study its anti-cancer effects and mechanisms. Cancer stem cell property was checked by tumor sphere formation and markers including CD133, Nanog, c-Myc, and TLF4.

Results

Immunohistochemical (IHC) analysis revealed that NLK expression was up-regulated in NSCLC cases (p < 0.001) and correlated with tumor T stage (p < 0.05). Silencing of NLK suppressed cell proliferation and tumorigenicity significantly in vitro and in vivo, which might be modulated by JUN family proteins. Furthermore, metformin selectively inhibits NLK expression and proliferation in NSCLC cells, but not immortalized noncancerous lung bronchial epithelial cells. In addition, both NLK knockdown and metformin treatment reduced the tumor sphere formation capacity and percentage of CD133+ cells. Accordingly, the expression level of stem cell markers (Nanog, c-Myc, and TLF4) were decreased significantly.

Conclusion

NLK is critical for cancer cell cycle progression, and tumorigenesis in NSCLC, NLK knockdown, and metformin treatment inhibit cancer cell proliferation and stemness. Metformin inhibits NLK expression and might be a potential treatment strategy for NSCLC.

Genome-wide screen identified let-7c/miR-99a/miR-125b regulating tumor progression and stem-like properties in cholangiocarcinoma

Cholangiocarcinoma (CCA), which is a poor prognosis malignancy that arises from the malignant transformation of cholangiocytes, is associated with chronic inflammation of the biliary epithelium. Thus far, the molecular mechanisms of the origin and neoplastic processes of CCA that are promoted by inflammation are still unclear and need to be fully elucidated. Here using small RNA sequencing to determine the microRNA (miRNA) expression profiles in CCA, we found that let-7c, miR-99a and miR-125b, which are three miRNAs of the same cluster, were downregulated in CCA and targeted interleukin 6 (IL-6), IL-6R and type 1 insulin-like growth factor, which are important cytokines and receptors of the IL-6/signal transducer and activator 3 (STAT3) pathway and have key roles in inflammation and CCA initiation. We also found that enforced expression of let-7c, miR-99a or miR-125b could reduce the activity of STAT3 and further suppress CCA tumorigenicity in vivo and inhibit the migration and invasion of CCA cells in vitro. Surprisingly, let-7c/miR-99a/miR-125b cluster also significantly decreased the ability of CCA cells for cancer stem cell-like mammosphere generation by downregulating CD133 and CD44, which suggests the pivotal roles of let-7c, miR-99a and miR-125b in CCA by regulating both inflammation and stem-like properties. Our findings showed potential links between miRNAs and inflammation, and provide a potential treatment strategy for developing an miRNA-based therapy via IL-6/STAT3 targeting for CCA.

Current approaches in identification and isolation of human renal cell carcinoma cancer stem cells

In recent years, cancer stem cells (CSCs)/tumor initiating cells (TICs) have been identified inside different tumors. However, currently used anti-cancer therapies are mostly directed against somatic tumor cells without targeting CSCs/TICs. CSCs/TICs also gain resistance to chemotherapies/radiotherapies. For the development of efficient treatment strategies, choosing the best method for isolation and characterization of CSCs/TICs is still debated among the scientific community. In this review, we summarize recent data concerning isolation techniques for CSCs using magnetic cell sorting and flow cytometry. The review focuses on the strategies for sample preparation during flow cytometric analysis, elaborating biomarkers such as CXCR4, CD105, and CD133. In addition, functional properties characteristic of CSCs/TICs using side population selection through Hoechst 33342 dye, aldehyde dehydrogenase 1, dye-cycle violet, and rhodamine 123 are also discussed. We also include a special focus on enriching CSCs/TICs using three-dimensional cell culture models such as agarose–agarose microbeads and sphere formation.

High expression of miR-9 in CD133+ glioblastoma cells in chemoresistance to temozolomide

Glioblastoma Multiforme (GBM), a uniformly lethal stage IV astrocytoma, is currently treated with a combination of surgical and radiation therapy as well as Temozolomide (TMZ) chemotherapy. Resistance to TMZ is rapidly acquired by GBM cells and overcoming this resistance has been an area of signi?cant research. GBM 'cancer stem cells' (CSC) also known as 'cancer initiating cells' are often positively selected by CD133 expression and TMZ resistance. In this project, we selected GBM CSC from two cell lines based on CD133 expression. CD133⁺ and CD133^- GBM cells showed comparable cell cycle status. The expression of genes within the Sonic Hedgehog Signaling pathway, PTCH1 (SHH receptor/basal signaling repressor) and Gli1 (effector transcription factor) were increased. The recent literature indicated a decreased in PTCH expression by miRNA and this was independent of SHH expression. We analyzed 5 potential PTCH-targeting miRNA and identi?ed an increase in miRNA-9-2. The CD133⁺ cells showed an increase in the Multiple Drug Resistance 1 gene (MDR1). Knockdown of Gli1 and MDR1 with siRNA enhanced TMZ induced cell death. Taken together, these studies show CD133⁺ GBM CSCs expressed greater levels of miR-9 and activation of the SHH/PTCH1/MDR1 axis. This axis has been shown to impart TMZ resistance. In the case of the CD133⁺ cells, the resistance is not acquires but seems to be inherent. Identi?cation of this pathway as well as the identi?cation of miR-9 may allow for the development of miRNA-targeted approach to Cancer Stem Cell therapy in GBM.

Neural stem/progenitor cells react to non-glial cns neoplasms

It is well established that the normal human brain contains populations of neural stem/progenitor cells. Recent studies suggest that they migrate toward a variety of CNS tissue injuries. In an investigation of the potential role of neural stem cells in the pathogenesis of primary CNS lymphomas (NHL-CNS), we observed that neural stem/progenitor cells appeared to accumulate at the border of the tumors with the brain and in the advancing edge of the tumors, in a pattern similar to that seen with reactive gliosis. We identified neural stem/progenitor cells using standard immunohistochemical markers thereof, including CD133, nestin, Group II Beta-tubulin, Musashi1, and the transcription factor Sox2, in neurosurgically obtained specimens of NHL-CNS metastatic carcinoma , and metastatic melanoma . We had similar results with each of these markers but found that Sox2 antibodies provided the clearest and most robust labeling of the cells at the borders of these non-glial tumors. To exclude that the immunoreactive cells were actually neoplastic, double-label immunohistochemistry for Sox2 and CD20 (for NHL-CNS), Sox2 and cytokeratin (CAM5.2, for carcinomas), or Sox2 and HMB45 (for melanomas) showed that in each tumor type, Sox2-immunoreactive cells adjacent to and among the tumor cells were separate from neoplastic cells. Sox2/GFAP double-labeling revealed a consistent pattern of Sox2 immunopositivity both in reactive GFAP-immunopositive astrocytes and in GFAP-negative cells, at the interface of tumor and non-neoplastic brain. These results suggest that neural stem/progenitor cells migrate to non-glial neoplasms in the CNS, are a source of reactive astrocytes, and that Sox2 is a reliable immunohistochemical marker for these cells.

Notch signaling and EMT in non-small cell lung cancer: biological significance and therapeutic application

Through epithelial-mesenchymal transition (EMT), cancer cells acquire enhanced ability of migration and invasion, stem cell like characteristics and therapeutic resistance. Notch signaling regulates cell-cell connection, cell polarity and motility during organ development. Recent studies demonstrate that Notch signaling plays an important role in lung cancer initiation and cross-talks with several transcriptional factors to enhance EMT, contributing to the progression of non-small cell lung cancer (NSCLC). Correspondingly, blocking of Notch signaling inhibits NSCLC migration and tumor growth by reversing EMT. Clinical trials have showed promising effect in some cancer patients received treatment with Notch1 inhibitor. This review attempts to provide an overview of the Notch signal in NSCLC: its biological significance and therapeutic application.

Isolation of cancer stem cells from three human glioblastoma cell lines: characterization of two selected clones

Cancer stem cells (CSC) were isolated via a non-adherent neurosphere assay from three glioma cell lines: LI, U87, and U373. Using a clonal assay, two clones (D2 and F11) were selected from spheres derived from LI cells and were characterized for the: expression of stem cell markers (CD133, Nestin, Musashi-1 and Sox2); proliferation; differentiation capability (determined by the expression of GalC, βIII-Tubulin and GFAP); Ca²⁺ signaling and tumorigenicity in nude mice. Both D2 and F11 clones expressed higher levels of all stem cell markers with respect to the parental cell line. Clones grew more slowly than LI cells with a two-fold increase in duplication time. Markers of differentiation (βIII-Tubulin and GFAP) were expressed at high levels in both LI cells and in neurospheres. The expression of Nestin, Sox2, and βIII-Tubulin was down-regulated in D2 and F11 when cultured in serum-containing medium, whereas Musashi-1 was increased. In this condition, duplication time of D2 and F11 increased without reaching that of LI cells. D2, F11 and parental cells did not express voltage-dependent Ca²⁺-channels but they exhibited increased intracellular Ca²⁺ levels in response to ATP. These Ca²⁺ signals were larger in LI cells and in spheres cultured in serum-containing medium, while they were smaller in serum-free medium. The ATP treatment did not affect cell proliferation. Both D2 and F11 induced the appearance of tumors when ortotopically injected in athymic nude mice at a density 50-fold lower than that of LI cells. All these data indicate that both clones have characteristics of CSC and share the same stemness properties. The findings regarding the expression of differentiation markers and Ca²⁺-channels show that both clones are unable to reach the terminal differentiation. Both D2 and F11 might represent a good model to improve the knowledge on CSC in glioblastoma and to identify new therapeutic approaches.

Drosophila neuroblasts as a new model for the study of stem cell self-renewal and tumour formation

Drosophila larval brain stem cells (neuroblasts) have emerged as an important model for the study of stem cell asymmetric division and the mechanisms underlying the transformation of neural stem cells into tumour-forming cancer stem cells. Each Drosophila neuroblast divides asymmetrically to produce a larger daughter cell that retains neuroblast identity, and a smaller daughter cell that is committed to undergo differentiation. Neuroblast self-renewal and differentiation are tightly controlled by a set of intrinsic factors that regulate ACD (asymmetric cell division). Any disruption of these two processes may deleteriously affect the delicate balance between neuroblast self-renewal and progenitor cell fate specification and differentiation, causing neuroblast overgrowth and ultimately lead to tumour formation in the fly. In this review, we discuss the mechanisms underlying Drosophila neural stem cell self-renewal and differentiation. Furthermore, we highlight emerging evidence in support of the notion that defects in ACD in mammalian systems, which may play significant roles in the series of pathogenic events leading to the development of brain cancers.

Is CD133 expression a prognostic biomarker of non-small-cell lung cancer? A systematic review and meta-analysis

Background

The clinical and prognostic significance of CD133 in non-small-cell lung cancer (NSCLC) remains controversial. To clarify a precise determinant of the clinical significance of CD133, we conducted a systematic review and meta-analysis to evaluate the association of CD133 with prognosis and clinicopathological features of NSCLC patients.

Methods

The electronic and manual searches were performed through the database of Pubmed, Medline, Web of Science, Scopus, and Chinese CNKI (from January 1, 1982 to January 1, 2014) for titles and abstracts by using the following keywords: “CD133”, “ac133” or “Prominin-1”, and “lung cancer” to identify the studies eligible for our analysis. Meta-analysis was performed by using Review Manager 5.0 and the outcomes included the overall survival and various clinicopathological features.

Results

A total of 23 studies were finally included, and our results showed that CD133 level was significantly correlated with the overall survival (OR = 2.25, 95% CI: 1.24–4.07, P = 0.008) of NSCLC patients but not with the disease free survival (OR = 1.33, 95% CI = 0.77–2.30, P = 0.31). With respect to clinicopathological features, CD133 level was positively correlated with lymph node metastasis (OR = 1.99, 95%CI = 1.06–3.74, P = 0.03), but not correlated with the histological classification (OR = 1.00, 95%CI = 0.81–1.23, P = 0.99(ac), OR = 0.87, 95%CI = 0.61–1.24, P = 0.45(sc)), or differentiation (OR = 0.94, 95%CI 0.53–1.68, Z = 0.20, P = 0.84 random-effect) of NSCLC patients.

Conclusion

High level of CD133 expression trends to correlate with a worse prognosis and a higher rate of lymph node metastasis in NSCLC patients, revealing CD133 as a potential pathological prognostic marker for NSCLC patients.

Maintenance of stemness in oxaliplatin-resistant hepatocellular carcinoma is associated with increased autocrine of IGF1

BACKGROUND

Evidence suggests that many types of cancers are composed of different cell types, including cancer stem cells (CSCs). We have previously shown that the chemotherapeutic agent oxaliplatin induced epithelial-mesenchymal transition, which is thought to be an important mechanism for generating CSCs. In the present study, we investigate whether oxaliplatin-treated cancer tissues possess characteristics of CSCs, and explore oxaliplatin resistance in these tissues.

METHODS

Hepatocellular carcinoma cells (MHCC97H cells) were subcutaneously injected into mice to form tumors, and the mice were intravenously treated with either oxaliplatin or glucose. Five weeks later, the tumors were orthotopically xenografted into livers of other mice, and these mice were treated with either oxaliplatin or glucose. Metastatic potential, sensitivity to oxaliplatin, and expression of CSC-related markers in the xenografted tumor tissues were evaluated. DNA microarrays were used to measure changes in gene expression as a result of oxaliplatin treatment. Additionally, an oxaliplatin-resistant cell line (MHCC97H-OXA) was established to assess insulin-like growth factor 1 secretion, cell invasion, cell colony formation, oxaliplatin sensitivity, and expression of CSC-related markers. The effects of an insulin-like growth factor 1 receptor inhibitor were also assessed.

RESULTS

Oxaliplatin treatment inhibited subcutaneous tumor growth. Tumors from oxaliplatin-treated mice that were subsequently xenografted into livers of other mice exhibited that decreasing sensitivity to oxaliplatin and increasing pulmonary metastatic potential. Among the expression of CSC-related proteins, the gene for insulin-like growth factor 1, was up-regulated expecially in these tumor tissues. Additionally, MHCC97H-OXA cells demonstrated that increasing cell invasion, colony formation, and expression of insulin-like growth factor 1 and CSC-related markers, whereas treatment with an inhibitor of the insulin-like growth factor 1 receptor suppressed these effects.

CONCLUSION

Maintenance of stemness in oxaliplatin-resistant hepatocellular carcinoma cells is associated with increased autocrine of IGF1.

The roles of mesenchymal stem cells in tumor inflammatory microenvironment

Tumor behavior is not entirely determined by tumor cells. Studies have demonstrated that a variety of non-tumor cells in the tumor microenvironment affect tumor behavior; thus, a new focus of cancer research has been the development of novel cancer treatment ideas and therapeutic targets based on the effects of these cells. Mesenchymal stem cells (MSCs) are an important component of the tumor microenvironment; however, previous studies have produced controversial results regarding whether MSCs promote or inhibit tumor growth and progression. In particular, Naïve MSCs and tumor-derived MSCs (T-MSCs) have different functions. Naïve MSCs could exert bidirectional effects on tumors because these cells can both promote and inhibit tumor progression while T-MSCs promote tumor progression due to influences from the tumor itself and from the inflammatory tumor microenvironment. As an unhealed wound, tumor produces a continuous source of inflammatory mediators and causes aggregation of numerous inflammatory cells, which constitute an inflammatory microenvironment. Inflammatory factors can induce homing of circulating MSCs and MSCs in adjacent tissues into tumors, which are then being “educated” by the tumor microenvironment to support tumor growth. T-MSCs could recruit more immune cells into the tumor microenvironment, increase the proportion of cancer stem cells and promote tumor angiogenesis, further supporting tumor progression. However, as plasticity is a fundamental feature of MSCs, MSCs can also inhibit tumors by activating various MSC-based signaling pathways. Studies of the mechanisms by which interactions among tumors, MSCs, and the inflammatory microenvironment occur and methods to disrupt these interactions will likely reveal new targets for cancer therapy.

Fluorescence in situ hybridization (FISH): an increasingly demanded tool for biomarker research and personalized medicine

Extensive studies of the genetic aberrations related to human diseases conducted over the last two decades have identified recurrent genomic abnormalities as potential driving factors underlying a variety of cancers. Over the time, a series of cutting-edge high-throughput genetic tests, such as microarrays and next-generation sequencing, have been developed and incorporated into routine clinical practice. Although it is a classical low-throughput cytogenetic test, fluorescence in situ hybridization (FISH) does not show signs of fading; on the contrary, it plays an increasingly important role in detecting specific biomarkers in solid and hematologic neoplasms and has therefore become an indispensable part of the rapidly developing field of personalized medicine. In this article, we have summarized the recent advances in FISH application for both de novo discovery and routine detection of chromosomal rearrangements, amplifications, and deletions that are associated with the pathogenesis of various hematopoietic and non-hematopoietic malignancies. In addition, we have reviewed the recent developments in FISH methodology as well.

Signaling pathways in the development of infantile hemangioma

Infantile hemangioma (IH), which is the most common tumor in infants, is a benign vascular neoplasm resulting from the abnormal proliferation of endothelial cells and pericytes. For nearly a century, researchers have noted that IH exhibits diverse and often dramatic clinical behaviors. On the one hand, most lesions pose no threat or potential for complication and resolve spontaneously without concern in most children with IH. On the other hand, approximately 10% of IHs are destructive, disfiguring and even vision- or life-threatening. Recent studies have provided some insight into the pathogenesis of these vascular tumors, leading to a better understanding of the biological features of IH and, in particular, indicating that during hemangioma neovascularization, two main pathogenic mechanisms prevail, angiogenesis and vasculogenesis. Both mechanisms have been linked to alterations in several important cellular signaling pathways. These pathways are of interest from a therapeutic perspective because targeting them may help to reverse, delay or prevent hemangioma neovascularization. In this review, we explore some of the major pathways implicated in IH, including the VEGF/VEGFR, Notch, β-adrenergic, Tie2/angiopoietins, PI3K/AKT/mTOR, HIF-α-mediated and PDGF/PDGF-R-β pathways. We focus on the role of these pathways in the pathogenesis of IH, how they are altered and the consequences of these abnormalities. In addition, we review the latest preclinical and clinical data on the rationally designed targeted agents that are now being directed against some of these pathways.

Megakaryocytes regulate the quiescence of hematopoietic stem cells through PF4: 2013 ASH meeting highlights

Hematopoietic stem cells (HSCs) can take one of the three different pathways: quiescence, self-renewal and differentiation. Mechanisms that control the tight balance to maintain lifelong hematopoietic homeostasis have been a major interest of research. Platelet factor-4 (PF4), a weak chemokine, is synthesized exclusively by megakaryocytes and sequestered in platelets. This meeting report highlights a novel study presented at 2013 ASH annual meeting. This study found that megakaryocyte, a progeny of HSC, was involved in maintaining quiescence of HSCs via PF4 in a feedback loop.

Modification of sialylation mediates the invasive properties and chemosensitivity of human hepatocellular carcinoma

Aberrant sialylation is closely associated with malignant phenotypes of tumor cells, including invasiveness and metastasis. This study investigated sialylation with regard to the modification of invasive properties and chemosensitivity in human hepatocellular carcinoma (HCC) cell lines and the association between the sialyltransferase gene family and clinicopathological characteristics in HCC patients. Using mass spectrometry analysis, we found that the composition profiling of sialylated N-glycans differed between MHCC97H and MHCC97L cells with different metastatic potential. The expressional profiles of 20 sialyltransferase genes showed differential expression in two cell lines, transitional and tumor tissues, from the same patients. Two genes, ST6GAL1 and ST8SIA2, were detected as overexpressed in MHCC97H and MHCC97L cells. The altered expression levels of ST6GAL1 and ST8SIA2 corresponded to a changed invasive phenotype and chemosensitivity of MHCC97H and MHCC97L cells both in vitro and in vivo. Further data indicated that manipulation of the expression of the two genes led to altered activity of the phosphoinositide-3 kinase (PI3K)/Akt signaling pathway. Targeting the PI3K/Akt pathway by its specific inhibitor wortmannin or by Akt RNA interference resulted in a reduced capacity for invasion and chemoresistance of MHCC97H cells. Our results imply that sialylation may function as an internal factor, regulating the invasion and chemosensitivity of HCC, probably through ST6GAL1 or ST8SIA2 regulation of the activity of the PI3K/Akt pathway.

Enhancing bone marrow regeneration by SALL4 protein

Hematopoietic stem cells (HSCs) are widely used in transplantation therapy to treat a variety of blood diseases. The success of hematopoietic recovery is of high importance and closely related to the patient’s morbidity and mortality after Hematopoietic stem cell transplantation (HSCT). We have previously shown that SALL4 is a potent stimulator for the expansion of human hematopoietic stem/progenitor cells in vitro. In these studies, we demonstrated that systemic administration with TAT-SALL4B resulted in expediting auto-reconstitution and inducing a 30-fold expansion of endogenous HSCs/HPCs in mice exposed to a high dose of irradiation. Most importantly, TAT-SALL4B treatment markedly prevented death in mice receiving lethal irradiation. Our studies also showed that TAT-SALL4B treatment was able to enhance both the short-term and long-term engraftment of human cord blood (CB) cells in NOD/SCID mice and the mechanism was likely related to the in vivo expansion of donor cells in a recipient. This robust expansion was required for the association of SALL4B with DNA methyltransferase complex, an epigenetic regulator critical in maintaining HSC pools and in normal lineage progression. Our results may provide a useful strategy to enhance hematopoietic recovery and reconstitution in cord blood transplantation with a recombinant TAT-SALL4B fusion protein.

PKH(high) cells within clonal human nephrospheres provide a purified adult renal stem cell population

The existence and identification of adult renal stem cells is a controversial issue. In this study, renal stem cells were identified from cultures of clonal human nephrospheres. The cultured nephrospheres exhibited the activation of stem cell pathways and contained cells at different levels of maturation. In each nephrosphere the presence of 1.12-1.25 cells mirroring stem cell properties was calculated. The nephrosphere cells were able to generate three-dimensional tubular structures in 3D cultures and in vivo. In clonal human nephrospheres a PKH(high) phenotype was isolated using PKH26 epifluorescence, which can identify quiescent cells within the nephrospheres. The PKH(high) cells, capable of self-renewal and of generating a differentiated epithelial, endothelial and podocytic progeny, can also survive in vivo maintaining the undifferentiated status. The PKH(high) status, together with a CD133(+)/CD24(-) phenotype, identified a homogeneous cell population displaying in vitro self-renewal and multipotency capacity. The resident adult renal stem cell population isolated from nephrospheres can be used for the study of mechanisms that regulate self-renewal and differentiation in adult renal tissue as well as in renal pathological conditions.