Ribosomal protein S15A augments human osteosarcoma cell proliferation in vitro

As a highly conserved housekeeping gene, the biological implications of ribosomal protein S15A (RPS15A) during various processes, including carcinogenesis, remain elusive. Herein, the authors reported that knockdown of RPS15A expression significantly inhibited human osteosarcoma U2OS cell proliferation and colony formation in vitro by using a lentivirus-mediated RNA interference (RNAi) system. Moreover, an excess accumulation of cells in the G0/G1 phase was observed in U2OS cells transduced with lentivirus targeting RPS15A, suggesting that the growth inhibition mediated by RPS15A knockdown in osteosarcoma cells was probably due to the induction of cell cycle arrest. Taken together, this study highlights the crucial role of RPS15A in promoting osteosarcoma cell proliferation, and provides a foundation for further study into the clinical potential of inhibition of RPS15A for the treatment of osteosarcoma.

Chrysophanol affords neuroprotection against microglial activation and free radical-mediated oxidative damage in BV2 murine microglia

In this study, chrysophanol, isolated from a marine fungus, was examined for its protective effects against inflammatory responses and oxidative stress in BV2 microglia. Chrysophanol was studied to assess its capabilities of protecting against lipopolysaccharide (LPS)-induced inflammatory responses in BV2 cells. It was found that chrysophanol reduced the level of nitric oxide (NO) and prostaglandin-E2 (PGE2) production by diminishing reducing the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Assessment of the inhibitory activities of chrysophanol on the generation of pro-inflammatory cytokines was also performed. Furthermore, Chrysophanol treatment significantly reduced intracellular reactive oxygen species (ROS)-mediated cell damage and inhibited DNA oxidation in BV2 cells. Moreover, antioxidative mechanisms by of chrysophanol were evaluated investigated by measuring the expression levels of antioxidative enzymes such superoxide dismutase (SOD) and glutathione (GSH). Therefore, results suggested that chrysophanol has potential antioxidant and anti-inflammatory activities in microglia and further might be a useful therapeutic agent for the treatment of neurodegenerative diseases.

IL-1β induces IL-6 production in retinal Müller cells predominantly through the activation of p38 MAPK/NF-κB signaling pathway

IL-6 plays an important role in various inflammatory ocular diseases, including diabetic retinopathy. Müller cells are the major source of inflammatory mediators, including IL-6, in the retina. However, the mechanism of regulating IL-6 production in these cells remains unclear. Examination of signaling pathways in human retinal Müller cells (MIO-M1 cell line) cultured with IL-1β, TNF-α, IL-6, IL-8, VEGF, IFN-γ, glucose or mannitol showed that IL-1β was the most potent stimulator of IL-6 production. In addition, IL-1 β also increased NF-κB p50 protein level and phosphorylation of p38 MAPK, ERK1/2 and c-Jun. Induction of IL-6 production by IL-1β was significantly reduced by addition of p38 MAPK (SB203580), MEK1/2 (U0126) or NF-κB (BAY11-7082) inhibitors, with the highest effect being observed with SB203580. To explore the specific elements in IL-6 promoter responsible for IL-1β-induction of IL-6 expression, a series of plasmids bearing various IL-6 promoter mutations were transiently expressed in MIO-MI cells cultured in the presence or absence of IL-1β (10ng/ml) and/or SB203580 (10µM). Results showed that IL-6 promoter activity of the parent pIL-6-Luc651 was significantly enhanced by IL-1β, but the level was significantly attenuated by SB203580. Furthermore, the IL-6 promoter activity was also reduced upon deletion of NF-κB, AP-1 or C/EBP binding sites, with NF-κB deletion being the greatest. These results are the first demonstration that IL-1β induces IL-6 production in Müller cells by activation of IL-6 promoter activity predominantly through the p38 MAPK/NF-κB pathway.

Lentivirus-mediated silencing of spindle and kinetochore-associated protein 1 inhibits the proliferation and invasion of neuronal glioblastoma cells

Spindle and kinetochore‑associated protein 1 (SKA1) is an important component of the human kinetochore, which plays a key role in mitosis. The resent study was designed to investigate the role of SKA1 in human glioblastoma. The results of the present study demonstrated that SKA1 was expressed in human glioblastoma cells. In addition, the knockdown of SKA1 expression in the A172 and U251 human glioblastoma cell lines was accomplished using a lentivirus infection method. An MTT assay demonstrated that downregulation of SKA1 may inhibit cell proliferation, without affecting the cell cycle. Furthermore, knockdown of SKA1 expression resulted in reduced cell invasion. The results of the present study indicated that SKA1 may be a potential target protein for antiproliferative and anti‑invasive therapeutic strategies of human glioblastoma.

Aggressive posterior retinopathy of prematurity in two of the triplets: a case report

Aggressive posterior retinopathy of prematurity is identified as a rare, rapidly progressing and severe form of retinopathy of prematurity (ROP). Here, we report the diagnosis and treatment of aggressive posterior retinopathy of prematurity (APROP) in two of the triplets born at low birth weight and small gestational age. A case concerning two triplets who were born at 31 weeks' gestational age with low birth weight and reached bilateral threshold APROP was reported. The ROP of triplets A and B had the characteristic features of aggressive diseases, which were posterior location, prominence of plus disease and rapid progression. Low birth weight and small gestational age, multiple pregnancies, pregnancy-induced hypertension and older age of the mother might account for the presentations of APROP. These cases demonstrate the importance of early screening and diagnosis in APROP infants. Prompt and adequate laser photocoagulation with a large number of high-intensity closely performed spots and early retreatment could be effective and safe for preventing the progression of APROP with plus disease in zone 1 or 2 in premature triplets.

Age-related cataract, cataract surgery and subsequent mortality: a systematic review and meta-analysis

PURPOSE

Changes in lens may reflect the status of systemic health of human beings but the supporting evidences are not well summarized yet. We aimed to determine the relationship of age-related cataract, cataract surgery and long-term mortality by pooling the results of published population-based studies.

METHODS

We searched PubMed and Embase from their inception till March, 2014 for population-based studies reporting the associations of any subtypes of age-related cataract, cataract surgery with all-cause mortality. We pooled the effect estimates (hazards ratios [HRs]) under a random effects model.

RESULTS

Totally, we identified 10 unique population-based studies including 39,659 individuals at baseline reporting the associations of any subtypes of cataract with all-cause mortality from 6 countries. The presence of any cataract including cataract surgery was significantly associated with a higher risk of death (pooled HR: 1.43, 95% CI, 1.21, 2.02; P<0.001; I(2) = 64.2%). In the meta-analysis of 9 study findings, adults with nuclear cataract were at higher risks of mortality (pooled HR: 1.55, 95% CI, 1.17, 2.05; P = 0.002; I(2) = 89.2%). In the meta-analysis of 8 study findings, cortical cataract was associated with higher risks of mortality (pooled HR: 1.26, 95% CI, 1.12, 1.42; P<0.001, I(2) = 29.7%). In the meta-analysis of 6 study findings, PSC cataract was associated with higher risks of mortality (pooled HR: 1.37, 95% CI, 1.04, 1.80; P = 0.03; I(2) = 67.3%). The association between cataract surgery and mortality was marginally non-significant by pooling 8 study findings (pooled HR: 1.27, 95% CI, 0.97, 1.66; P = 0.08; I(2)= 76.6%).

CONCLUSIONS

All subtypes of age-related cataract were associated with an increased mortality with nuclear cataract having the strongest association among the 3 cataract subtypes. However, cataract surgery was not significantly related to mortality. These findings indicated that changes in lens may serve as markers for ageing and systemic health in general population.

IL-1β Upregulates IL-8 Production in Human Müller Cells Through Activation of the p38 MAPK and ERK1/2 Signaling Pathways

Diabetic retinopathy shares some similarity with chronic inflammation and Müller cells dysfunction may play an important role in its initiation and progression since these cells are thought to be a major source of inflammatory factors. The goal of this study was to examine the effect of cytokines on human retinal Müller cells and to understand the underlying signal transduction pathways regulating interleukin-8 (IL-8) expression. In this study, human MIO-M1 cells were treated with interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-8, vascular endothelial growth factor (VEGF), interferon-gamma (IFN-γ), glucose, or mannitol, followed by examination of their IL-8 protein and mRNA levels by Western blotting and PCR, respectively. After treatment with IL-1β, the levels of phosphorylated p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK), Janus kinase 2 (JAK2), and signal transducer and activator of transcription 3 (STAT3) were measured. IL-8 was also measured by Western blotting and ELISA following Müller cell culture with IL-1β and specific inhibitors of the p38 MAPK, ERK1/2, JNK, or JAK2 pathways. The results showed that IL-1β was a potent inducer of IL-8 expression in MIO-M1 cells, although a relatively small increase was induced by TNF-α. IL-6, IL-8, VEGF, and IFN-γ did not modify IL-8 expression. Increase of IL-8 expression was accompanied by a significant increased phosphorylation of p38 MAPK, ERK, and JNK, but not of JAK2 and STAT3. Furthermore, inhibitors of p38 MAPK and MEK1/2, but not for JNK and JAK2, significantly inhibited IL-8 expression. In conclusion, IL-1β potently stimulates IL-8 expression in Müller cells mainly through the p38 MAPK and ERK1/2 pathways.

Emodin-loaded magnesium silicate hollow nanocarriers for anti-angiogenesis treatment through inhibiting VEGF

The applications of anti-VEGF (vascular endothelial growth factor) treatment in ophthalmic fields to inhibit angiogenesis have been widely documented in recent years. However, the hydrophobic nature of many agents makes its delivery difficult in practice. Therefore, the aim of the present study was to introduce a new kind of hydrophobic drug carrier by employing nanoparticles with a hollow structure inside. Followed by the synthesis and characterization of magnesium silicate hollow spheres, cytotoxicity was evaluated in retina capillary endothelial cells. The loading and releasing capacity were tested by employing emodin, and the effect on VEGF expression was performed at the gene and protein level. Finally, an investigation on angiogenesis was carried on fertilized chicken eggs. The results indicated that the magnesium silicate nanoparticles had low toxicity. Emodin–MgSiO₃ can inhibit the expression of both VEGF gene and protein effectively. Angiogenesis of eggs was also reduced significantly. Based on the above results, we concluded that magnesium silicate hollow spheres were good candidates as drug carriers with enough safety.

PPM1D silencing by RNA interference inhibits the proliferation of lung cancer cells

BACKGROUND

PPM1D (protein phosphatase, Mg2+/Mn2+ dependent, 1D) has been reported to be involved in multiple human tumors. This study was designed to investigate the functional role of PPM1D in lung cancer cells.

METHODS

Expression levels of PPM1D were analyzed in A549 and H1299 cells by real-time PCR and Western blotting. Lentivirus-mediated short hairpin RNA (shRNA) was used to knock down PPM1D expression in both cell lines. The effects of PPM1D on lung cancer cell growth were investigated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), colony formation and flow cytometry assays.

RESULTS

Knockdown of PPM1D in lung cancer cells resulted in decreased cell proliferation and impaired colony formation ability. Moreover, flow cytometry analysis showed that knockdown of PPM1D arrested cell cycle at the G0/G1 phase. Furthermore, PPM1D silencing downregulated the expression of cyclin B1 in H1299 cells. Therefore, it is reasonable to speculate that the mechanisms by which PPM1D knockdown alleviates cell growth may be partly via the induction of cell cycle arrest due to the suppression of cyclin B1.

CONCLUSIONS

These results suggest that PPM1D silencing by RNA interference (RNAi) may be a potential therapeutic approach for the treatment of lung cancer.

GSK-3β inhibition promotes early engraftment of ex vivo-expanded haematopoietic stem cells

OBJECTIVES

Umbilical cord blood (UCB) is a source of stem cells used for allogeneic transplantation, in addition to bone marrow and peripheral blood. Limited numbers of stem cells in a single UCB unit is associated with slow haematopoietic recovery and high risk of graft failure, particularly in adult patients. UCB stem cells can be expanded ex vivo; however, rapid differentiation reduces their regenerative potential. We have recently shown that Wnt/β-catenin signalling is down-regulated in ex vivo-expanded stem cells; therefore, we propose that re-activation of Wnt signalling using GSK-3β inhibition may act to improve regenerative potential of these ex vivo-expanded stem cells.

MATERIALS AND METHODS

Immunocompromised mice were employed in transplantation studies to determine stem-cell engraftment. Flow cytometry was used to phenotype the engrafted human cells. Retroviral gene transfer was used to examine the role of Myc gene up-regulated by GSK-3β inhibition, in ex vivo-expanded stem cells.

RESULTS

Treatment with GSK-3β inhibitor, 6-bromoindirubin 3'-oxime (BIO) improved early human cell engraftment in the mice and elevated the numbers of myeloid progenitor cells in cytokine-stimulated culture. BIO up-regulated β-catenin and c-myc in ex vivo-expanded stem cells. Ectopic expression of Myc acted to increase clonogenic potential and to delay differentiation of haematopoietic progenitor cells, suggesting the potential mechanism to improve regenerative potential of ex vivo-expanded grafts.

CONCLUSIONS

Pharmacological inhibition of GSK-3β provided a novel approach to improve early engraftment of ex vivo-expanded haematopoietic progenitor cells.

Observational follow-up of the PROactive study: a 6-year update

AIMS

The PROactive study investigated pioglitazone for secondary prevention of macrovascular events in type 2 diabetes mellitus. Pioglitazone showed a 10% (non-significant) relative risk (RR) reduction for the primary composite endpoint and a significant 16% reduction for the main secondary endpoint (death, myocardial infarction, stroke) after a mean 34.5 months. There was no difference in cumulative malignancy incidence, but an imbalance in bladder malignancies (pioglitazone 14, placebo 5). We present a pre-specified 6-year interim analysis of a 10-year observational follow-up.

METHODS

Any patient completing PROactive was eligible. No study treatments were provided. A Cox proportional hazard model compared non-adjudicated macrovascular events (same endpoints as PROactive excluding acute coronary syndrome) based on original randomization. Malignancies were compared using conventional RR ratios.

RESULTS

Of 5238 randomized patients, 3599 (74%) entered the follow-up. For the follow-up (mean 5.8 years) or combined double-blind and follow-up periods (≤9.5 years, mean 8.7), there were no statistically significant differences in primary or main secondary endpoints. For the combined period, a similar percentage of patients had any diagnosed malignancy (RR = 1.05, 95% CI [0.89, 1.24]) or bladder malignancy (RR = 1.06, 95% CI [0.59, 1.89]) in the pioglitazone and placebo groups. There were fewer cases of bladder malignancy with pioglitazone (15 [0.6%] vs. 19 [0.7%] for placebo) for the combined period when events diagnosed in the first 365 days were excluded, and fewer cases for the follow-up period alone (10 [0.5%] vs. 17 [1.0%] for placebo). Further analyses of pioglitazone use (including use during follow-up) found no significant difference in bladder malignancies between any and no pioglitazone use for the combined period.

CONCLUSIONS

These data suggest that improved macrovascular outcomes seen with pioglitazone subside without continued pioglitazone treatment. The double-blind period bladder cancer imbalance did not persist in follow-up.

Aspect-driven, data-reflective and context-aware user interfaces design

The increasing use of Web-based applications continues to broaden the user groups of enterprise applications at large. Since ordinary users often equate the quality of user interface (UI) with the quality of the entire application, the importance of providing easy-to-use UIs has been significantly increasing. Unfortunately, designing a single UI satisfying all end users remains challenging. To address this issue, researchers and developers are looking to Context-aware/Adaptive UIs (CUIs) that aim to provide end users with more personalized user interaction experiences. Although multiple proposals have been made, very few production systems provide such malleable interfaces due to the excessive cost of development and maintenance.

In this paper, we propose a technique that aims to reduce development and maintenance efforts of CUI to a level comparable with a single UI. Unlike most of the existing CUI approaches, our technique does not involve an external UI model. Instead, it aims to reflect runtime-information and structures already captured in the application, while extending them to provide an appropriate CUI. With this technique, developers do not design forms or tables directly for each page or panel. Instead they design generic and reusable transformation rules capable of presenting application data instances in the UI while considering the runtime context. To demonstrate our technique and its impact on CUI development and maintenance, we provide a case study. Moreover, we present our experience from its application to an existing production-level enterprise application, with high demands on performance.

Effects of balanced dietary protein levels on egg production and egg quality parameters of individual commercial layers

The effects of a series of balanced dietary protein levels on egg production and egg quality parameters of laying hens from 18 through 74 wk of age were investigated. One hundred forty-four pullets (Bovans) were randomly assigned to individual cages with separate feeders including 3 different protein level series of isocaloric diets. Diets were separated into 4 phases of 18-22, 23-32, 33-44, and 45-74 wk of age. The high protein (H) series contained 21.62, 19.05, 16.32, and 16.05% CP, respectively. Medium protein (M) and low protein (L) series were 2 and 4% lower in balanced dietary protein. The results clearly demonstrated that the balanced dietary protein level was a limiting factor for BW, ADFI, egg weight, hen day egg production (HDEP), and feed per kilogram of eggs. Feeding with the L series resulted in lower ADFI and HDEP (90.33% peak production) and more feed per kilogram of eggs compared with the H or M series (HDEP; 93.23 and 95.68% peak production, monthly basis). Egg weight responded in a linear manner to balanced dietary protein level (58.78, 55.94, and 52.73 g for H, M, and L, respectively). Feed intake of all hens, but especially those in the L series, increased considerably after wk 54 when the temperature of the house decreased due to winter conditions. Thus, hens fed the L series seemed particularly dependent on house temperature to maintain BW, ADFI, and HDEP. For egg quality parameters, percent yolk, Haugh units, and egg specific gravity were similar regardless of diets. Haugh units were found to be greatly affected by the variation of housing temperature (P = 0.025). Maximum performance cannot always be expected to lead to maximum profits. Contrary to the idea of a daily amino acid requirement for maximum performance, these results may be used to determine profit-maximizing levels of balanced dietary protein based on the cost of protein and returns from different possible protein levels that may be fed.

Elevated cell proliferation and VEGF production by high-glucose conditions in Müller cells involve XIAP

PURPOSE

Müller cells have important roles in the pathogenesis of diabetic retinopathy by promoting cell proliferation and inducing the production of vascular endothelial growth factor (VEGF) under hyperglycemic conditions. The objective of this study was to determine the potential mechanism of Müller cell proliferation and VEGF production due to high-glucose conditions.

METHODS

Primary cultured rat Müller cells were incubated with medium containing variable concentrations of glucose and/or embelin, a specific inhibitor of X-linked inhibitor of apoptosis protein (XIAP), for 72 h. The proliferation of Müller cells was assessed by the MTT assay. The expression and/or phosphorylation of 146 proteins were assessed using protein pathway array.

RESULTS

High concentrations of glucose-induced Müller cell proliferation and altered expression and/or phosphorylation of 47 proteins that have been identified to have key roles in several important signaling pathways (XIAP, VEGF, HIF1α, NFκB, etc) and are involved in the regulation of cell survival, proliferation, or apoptosis. However, Müller cell alterations induced by high-glucose conditions were counteracted by the XIAP inhibitor embelin, and 26 proteins/phosphorylations (out of 47) were restored to their normal levels. Nine proteins, including NFκB p65, p-p38, tumor necrosis factor-α, urokinase-type plasminogen activator, CREB, IL-1β, HCAM, estrogen receptor-α, and p-Stat3, were involved in regulatory networks between XIAP and VEGF.

CONCLUSIONS

The current study suggests that XIAP may be a potential regulator that can mediate a series of pathological changes induced by high-glucose conditions in Müller cells. Therefore, embelin could be a potential agent for the prevention and treatment of diabetic retinopathy.

Interpreting experiments on egg production--statistical considerations

A given data set can be analyzed many ways, but only one is the correct analysis based on the design actually used when running the experiment. This work gives a tutorial-like illustration of the effects of the presence of a regression variable (or covariate) on the recorded responses in an experiment set up as a standard factorial design and shows how the analysis results are to be adjusted for the presence of covariates. An underlying assumption of a factorial model is that each of the treatments (e.g., diets) is randomly allocated to different subjects (hens). When many measurements (e.g., over time) are made on the same subject (hen), this independence assumption is violated; in these cases, the design is an example from the class of repeated measures designs. The difference in analysis between factorial designs and repeated measures designs is also discussed. Then, the 2 concepts are merged wherein the results for a repeated measures analysis have to be adjusted for the presence of covariates. The paper concludes with analyses on the results of egg production responses from an experiment in which repeated measurements were made on the same hens and in which an unanticipated temperature covariate was present.

miR-27a regulates endothelial differentiation of breast cancer stem like cells

Recent studies suggested that cancer stem cells (CSCs) are capable of differentiating into endothelial cells and tumor endothelium may be derived from CSCs. But the mechanism remains unclear. We showed that vascular endothelial growth factor (VEGF) induced the expression of endothelial markers in breast cancer stem like cells (BCSLCs). In addition, the VEGF-treated BCSLCs formed capillary structure in matrigel and released vWF upon histamine treatment. The miR-27a expression was significantly increased in VEGF-treated BCSLCs. Antagonizing miR-27a by miR-27a anti-sense oligos (ASOs) in VEGF-treated BCSLCs led to decreased endothelial markers and function, while increasing miR-27a in BCSLCs resulted in enhanced endothelial properties. VEGF enhanced the transcription of miR-27a by increasing RUNX1 binding to miR-27a promoter. Increased miR-27a paralleled the reduced expression of ZBTB10, a known miR-27a target. Both expression of miR-27a and knockdown of ZBTB10 in BCSLCs promoted in vivo angiogenesis and tumor metastasis. Further, we demonstrated that VEGF-treated BCSLCs secreted more endogenous VEGF compared with undifferentiated BCSLCs. Thus, miR-27a promotes angiogenesis by mediating endothelial differentiation of BCSLCs and it may be a new target for anti-angiogenesis cancer therapy.

South African guideline for the management of chronic hepatitis B: 2013

Hepatitis B remains a significant yet preventable health issue in South Africa. The introduction of the hepatitis B vaccine into the country some 18 years ago has demonstrated benefit, but the exposure to, and prevalence of chronic HBsAg positivity remain unacceptably high. Those with chronic hepatitis B virus infection have an elevated risk of developing cirrhosis with end-stage liver disease and a markedly elevated risk of hepatocellular carcinoma, independent of the presence of cirrhosis. The challenge in South Africa remains prevention through the universal vaccination coverage of all children and the identification of those with chronic hepatitis B virus infection. Over the last decade our understanding of hepatitis B and its behaviour and natural history in those with chronic infection has significantly improved. This understanding is key to identifying those who warrant further evaluation and therapy. A number of global societies have updated their guidelines in recent years. This document draws on these guidelines and serves to contextualise, for South Africa, practice guidelines for the management of chronic hepatitis B.

Poly[[diaquabis{μ-4-[6-(4-carboxyphenyl)-4,4′-bipyridin-2-yl]benzoato-κ2O:N1′}copper(II)] dimethylformamide tetrasolvate]

In the title compound, {[Cu(C₂₄H₁₅N₂O₄)₂(H₂O)₂]·4C₃H₇NO}_n, the Cu^II ion, lying on an inversion center, is six-coordinated by two N atoms from two 4-[6-(4-carb­oxy­phen­yl)-4,4′-bipyridin-2-yl]benzoate (L) ligands, two deprotonated carboxyl­ate O atoms from two other symmetry-related L ligands and two water mol­ecules in a slightly distorted octa­hedral geometry. The Cu^II atoms are linked by the bridging ligands into a layer parallel to (101). The presence of intra­layer O—H⋯O hydrogen bonds and π–π inter­actions between the pyridine and benzene rings [centroid–centroid distances = 3.808 (2) and 3.927 (2) Å] stabilizes the layer. Further O—H⋯O hydrogen bonds link the layers and the dimethyl­formamide solvent mol­ecules.

Beclin 1 and autophagy are required for the tumorigenicity of breast cancer stem-like/progenitor cells

Malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew; these cells are known as cancer stem-like cells (CSCs) or tumor-initiating cells. Primitive mammary CSCs/progenitor cells can be propagated in culture as floating spherical colonies termed ‘mammospheres'. We show here that the expression of the autophagy protein Beclin 1 is higher in mammospheres established from human breast cancers or breast cancer cell lines (MCF-7 and BT474) than in the parental adherent cells. As a result, autophagic flux is more robust in mammospheres. We observed that basal and starvation-induced autophagy flux is also higher in aldehyde dehydrogenase 1-positive (ALDH1⁺) population derived from mammospheres than in the bulk population. Beclin 1 is critical for CSC maintenance and tumor development in nude mice, whereas its expression limits the development of tumors not enriched with breast CSCs/progenitor cells. We found that decreased survival in autophagy-deficient cells (MCF-7 Atg7 knockdown cells) during detachment does not contribute to an ultimate deficiency in mammosphere formation. This study demonstrates that a prosurvival autophagic pathway is critical for CSC maintenance, and that Beclin 1 plays a dual role in tumor development.