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Adverse effect of alcohol on neural function has been well documented. Especially,the teratogenic effect of alcohol on neurodevelopment during embryogenesis has been demonstrated in various models,which could be a pathologic basis for fetal alcohol spectrum disorders (FASDs). While the developmental defects from alcohol abuse during gestation have been described,the specific mechanisms by which alcohol mediates these injuries have yet to be determined. Recent studies have shown that alcohol has significant effect on molecular and cellular regulatory mechanisms in embryonic stem cell (ESC) differentiation including genes involved in neural development. To test our hypothesis that alcohol induces molecular alterations during neural differentiation we have derived neural precursor cells from pluripotent human ESCs in the presence or absence of ethanol treatment. Genome-wide transcriptomic profiling identified molecular alterations induced by ethanol exposure during neural differentiation of hESCs into neural rosettes and neural precursor cell populations. The Database for Annotation,Visualization and Integrated Discovery (DAVID) functional analysis on significantly altered genes showed potential ethanol's effect on JAK-STAT signaling pathway,neuroactive ligand-receptor interaction,Toll-like receptor (TLR) signaling pathway,cytokine-cytokine receptor interaction and regulation of autophagy. We have further quantitatively verified ethanol-induced alterations of selected candidate genes. Among verified genes we further examined the expression of P2RX3,which is associated with nociception,a peripheral pain response. We found ethanol significantly reduced the level of P2RX3 in undifferentiated hESCs,but induced the level of P2RX3 mRNA and protein in hESC-derived NPCs. Our result suggests ethanol-induced dysregulation of P2RX3 along with alterations in molecules involved in neural activity such as neuroactive ligand-receptor interaction may be a molecular event associated with alcohol-related peripheral neuropathy of an enhanced nociceptive response. View Publication

BACKGROUND: Malignant melanoma is an exceptionally aggressive,drug-resistant and heterogeneous cancer. Recently it has been shown that melanoma cells with high clonogenic and tumourigenic abilities are common,but markers distinguishing such cells from cells lacking these abilities have not been identified. There is therefore no definite evidence that an exclusive cell subpopulation,i.e. cancer stem cells (CSC),exists in malignant melanoma. Rather,it is suggested that multiple cell populations are implicated in initiation and progression of the disease,making it of importance to identify subpopulations with elevated aggressive properties. METHODS AND FINDINGS: In several other cancer forms,Aldehyde Dehydrogenase (ALDH),which plays a role in stem cell biology and resistance,is a valuable functional marker for identification of cells that show enhanced aggressiveness and drug-resistance. Furthermore,the presence of ALDH(+) cells is linked to poor clinical prognosis in these cancers. By analyzing cell cultures,xenografts and patient biopsies,we showed that aggressive melanoma harboured a large,distinguishable ALDH(+) subpopulation. In vivo,ALDH(+) cells gave rise to ALDH(-) cells,while the opposite conversion was rare,indicating a higher abilities of ALDH(+) cells to reestablish tumour heterogeneity with respect to the ALDH phenotype. However,both ALDH(+) and ALDH(-) cells demonstrated similarly high abilities for clone formation in vitro and tumour initiation in vivo. Furthermore,both subpopulations showed similar sensitivity to the anti-melanoma drugs,dacarbazine and lexatumumab. CONCLUSIONS: These findings suggest that ALDH does not distinguish tumour-initiating and/or therapy-resistant cells,implying that the ALDH phenotype is not associated with more-aggressive subpopulations in malignant melanoma,and arguing against ALDH as a universal" marker. Besides� View Publication

Aldehyde dehydrogenase 1 A1 (ALDH1A1) has recently been suggested as a marker for cancer stem or stem-like cancer cells of some human malignancies. The purpose of this study was to investigate the stem cell-related function and clinical significance of the ALDH1A1 in bladder urothelial cell carcinoma. Aldefluor assay was used to isolate ALDH1A1+ cells from bladder cancer cells. Stem cell characteristics of the ALDH1A1+ cells were then investigated by in vitro and in vivo approaches. Immunohistochemistry was done for evaluating ALDH1A1 expression on 22 normal bladder tissues and 216 bladder tumor specimens of different stage and grade. The ALDH1A1+ cancer cells displayed higher in vitro tumorigenicity compared with isogenic ALDH1A1- cells. The ALDH1A1+ cancer cells could generate xenograft tumors that resembled the histopathologic characteristics and heterogeneity of the parental cells. High ALDH1A1 expression was found in 26% (56 of 216) of human bladder tumor specimens and significantly related to advanced pathologic stage,high histologic grade,recurrence and progression,and metastasis of bladder urothelial cell carcinomas (all P textless 0.05). Furthermore,ALDH1A1 expression was inversely associated with cancer-specific and overall survivals of the patients (P = 0.027 and 0.030,respectively). Therefore,ALDH1A1+ cell population could be enriched in tumor-initiating cells. ALDH1A1 may serve as a useful marker for monitoring the progression of bladder tumor and identifying bladder cancer patients with poor prognosis who might benefit from adjuvant and effective treatments. View Publication

Although the concept that cancers originate from stem cells (SC) is becoming scientifically accepted,mechanisms by which SC contribute to tumor initiation and progression are largely unknown. For colorectal cancer (CRC),investigation of this problem has been hindered by a paucity of specific markers for identification and isolation of SC from normal and malignant colon. Accordingly,aldehyde dehydrogenase 1 (ALDH1) was investigated as a possible marker for identifying colonic SC and for tracking them during cancer progression. Immunostaining showed that ALDH1(+) cells are sparse and limited to the normal crypt bottom,where SCs reside. During progression from normal epithelium to mutant (APC) epithelium to adenoma,ALDH1(+) cells increased in number and became distributed farther up the crypt. CD133(+) and CD44(+) cells,which are more numerous and broadly distributed in normal crypts,showed similar changes during tumorigenesis. Flow cytometric isolation of cancer cells based on enzymatic activity of ALDH (Aldefluor assay) and implantation of these cells in nonobese diabetic-severe combined immunodeficient mice (a) generated xenograft tumors (Aldefluor(-) cells did not),(b) generated them after implanting as few as 25 cells,and (c) generated them dose dependently. Further isolation of cancer cells using a second marker (CD44(+) or CD133(+) serially) only modestly increased enrichment based on tumor-initiating ability. Thus,ALDH1 seems to be a specific marker for identifying,isolating,and tracking human colonic SC during CRC development. These findings also support our original hypothesis,derived previously from mathematical modeling of crypt dynamics,that progressive colonic SC overpopulation occurs during colon tumorigenesis and drives CRC development. View Publication

Tumor contains small population of cancer stem cells (CSC) that are responsible for its maintenance and relapse. Analysis of these CSCs may lead to effective prognostic and therapeutic strategies for the treatment of cancer patients. We report here the identification of CSCs from human lung cancer cells using Aldefluor assay followed by fluorescence-activated cell sorting analysis. Isolated cancer cells with relatively high aldehyde dehydrogenase 1 (ALDH1) activity display in vitro features of CSCs,including capacities for proliferation,self-renewal,and differentiation,resistance to chemotherapy,and expressing CSC surface marker CD133. In vivo experiments show that the ALDH1-positive cells could generate tumors that recapitulate the heterogeneity of the parental cancer cells. Immunohistochemical analysis of 303 clinical specimens from three independent cohorts of lung cancer patients and controls show that expression of ALDH1 is positively correlated with the stage and grade of lung tumors and related to a poor prognosis for the patients with early-stage lung cancer. ALDH1 is therefore a lung tumor stem cell-associated marker. These findings offer an important new tool for the study of lung CSCs and provide a potential prognostic factor and therapeutic target for treatment of the patients with lung cancer. View Publication

Glioblastoma (GBM) is the most aggressive primary brain tumor and is resistant to all therapeutic regimens. Relapse occurs regularly and might be caused by a poorly characterized tumor stem cell (TSC) subpopulation escaping therapy. We suggest aldehyde dehydrogenase 1 (ALDH1) as a novel stem cell marker in human GBM. Using the neurosphere formation assay as a functional method to identify brain TSCs,we show that high protein levels of ALDH1 facilitate neurosphere formation in established GBM cell lines. Even single ALDH1 positive cells give rise to colonies and neurospheres. Consequently,the inhibition of ALDH1 in vitro decreases both the number of neurospheres and their size. Cell lines without expression of ALDH1 do not form tumor spheroids under the same culturing conditions. High levels of ALDH1 seem to keep tumor cells in an undifferentiated,stem cell-like state indicated by the low expression of beta-III-tubulin. In contrast,ALDH1 inhibition induces premature cellular differentiation and reduces clonogenic capacity. Primary cell cultures obtained from fresh tumor samples approve the established GBM cell line results. View Publication

PURPOSE: To examine the role of cancer stem cells (CSC) in mediating metastasis in inflammatory breast cancer (IBC) and the association of these cells with patient outcome in this aggressive type of breast cancer. EXPERIMENTAL DESIGN: CSCs were isolated from SUM149 and MARY-X,an IBC cell line and primary xenograft,by virtue of increased aldehyde dehydrogenase (ALDH) activity as assessed by the ALDEFLUOR assay. Invasion and metastasis of CSC populations were assessed by in vitro and mouse xenograft assays. Expression of ALDH1 was determined on a retrospective series of 109 IBC patients and this was correlated with histoclinical data. All statistical tests were two sided. Log-rank tests using Kaplan-Meier analysis were used to determine the correlation of ALDH1 expression with development of metastasis and patient outcome. RESULTS: Both in vitro and xenograft assays showed that invasion and metastasis in IBC are mediated by a cellular component that displays ALDH activity. Furthermore,expression of ALDH1 in IBC was an independent predictive factor for early metastasis and decreased survival in this patient population. CONCLUSIONS: These results suggest that the metastatic,aggressive behavior of IBC may be mediated by a CSC component that displays ALDH enzymatic activity. ALDH1 expression represents the first independent prognostic marker to predict metastasis and poor patient outcome in IBC. The results illustrate how stem cell research can translate into clinical practice in the IBC field. View Publication

High levels of aldehyde dehydrogenase (ALDH) activity have been proposed to be a common feature of stem cells. Adult hematopoietic,neural,and cancer stem cells have all been reported to have high ALDH activity,detected using Aldefluor,a fluorogenic substrate for ALDH. This activity has been attributed to Aldh1a1,an enzyme that is expressed at high levels in stem cells and that has been suggested to regulate stem cell function. Nonetheless,Aldh1a1 function in stem cells has never been tested genetically. We observed that Aldh1a1 was preferentially expressed in mouse hematopoietic stem cells (HSCs) and expression increased with age. Hematopoietic cells from Aldh1a1-deficient mice exhibited increased sensitivity to cyclophosphamide in a non-cell-autonomous manner,consistent with its role in cyclophosphamide metabolism in the liver. However,Aldh1a1 deficiency did not affect hematopoiesis,HSC function,or the capacity to reconstitute irradiated recipients in young or old adult mice. Aldh1a1 deficiency also did not affect Aldefluor staining of hematopoietic cells. Finally,Aldh1a1 deficiency did not affect the function of stem cells from the adult central or peripheral nervous systems. Aldh1a1 is not a critical regulator of adult stem cell function or Aldefluor staining in mice. View Publication

INTRODUCTION: Lung cancer contains a small population of cancer stem cells that contribute to its initiation and progression. We investigated the biological function and clinical significance of aldehyde dehydrogenase 1A1 (ALDH1A1) in non-small-cell lung carcinoma (NSCLC). METHODS: ALDH1A1 assay or small interfering RNA transfection was employed to isolate ALDH1A1+ cells or knock down ALDH1A1 expression in H2087 cells,respectively. Biological functions of ALDH1A1+ and ALDH1A1 silenced cells were investigated using in vitro and in vivo methods. ALDH1A1 expression was analyzed using immunohistochemistry on tissue microarrays with 179 lung cancer tissues and 26 normal lung tissues. RESULTS: The abilities of clone formation,proliferation,cell growth,and migration were increased in ALDH1A1+ and ALDH1A1 silenced cells. ALDH1A1+ lung cancer cells initiated tumors that resembled the histopathologic characteristics and heterogeneity of the parental lung cancer cells in mice. The silencing of ALDH1A1 expression in H2087 lung cancer cells inhibited cell proliferation and migration significantly. ALDH1A1 was expressed in 42% of normal lung tissues (11 of 26),with strong expression in the basal cells and globular cells of the normal bronchus and weak expression in the alveolar epithelial cells. Compared with normal lung tissues,45% of NSCLC samples (81 of 179) were read as positive for ALDH1A1. Positive ALDH1A1 expression was correlated with patients' smoking status (p = 0.022),lymph-node metastasis (p = 0.006),clinical stage (p = 0.004),and a decreased overall survival time (p textless 0.001). Positive ALDH1A1 expression in lung cancer tissues was an independent prognostic factor for NSCLC (odds ratio = 5.232,p textless 0.001). CONCLUSION: Elucidating the biological functions of ALDH1A1 could be helpful in studying lung tumorigenesis and for developing new therapeutic approaches. View Publication

Aldehyde dehydrogenases (ALDHs) belong to a superfamily of NAD(P)+-dependent enzymes,which catalyze the oxidation of endogenous and exogenous aldehydes to their corresponding acids. Increased expression and/or activity of ALDHs,particularly ALDH1A1,have been reported to occur in human cancers. It is proposed that the metabolic function of ALDH1A1 confers the stemness" properties to normal and cancer stem cells. Nevertheless� View Publication