Showing papers on "Cell growth published in 2014"
TL;DR: The present status of the development of specific PI3K, Akt, and mTOR inhibitors, from already registered medicines to novel compounds that are just leaving the laboratory bench are addressed.
Abstract: The phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathways are two pathways crucial to many aspects of cell growth and survival, in physiological as well as in pathological conditions (e.g., cancer). Indeed, they are so interconnected that, in a certain sense, they could be regarded as a single, unique pathway. In this paper, after a general overview of the biological significance and the main components of these pathways, we address the present status of the development of specific PI3K, Akt, and mTOR inhibitors, from already registered medicines to novel compounds that are just leaving the laboratory bench.
1,075 citations
TL;DR: In mice, mammary tumor growth induces the accumulation of tumor-associated macrophage that are phenotypically and functionally distinct from mammary tissue macrophages, which reveal the ontogeny of TAMs and a discrete tumor-elicited inflammatory response, which may provide new opportunities for cancer immunotherapy.
Abstract: Long recognized as an evolutionarily ancient cell type involved in tissue homeostasis and immune defense against pathogens, macrophages are being rediscovered as regulators of several diseases, including cancer. Here we show that in mice, mammary tumor growth induces the accumulation of tumor-associated macrophages (TAMs) that are phenotypically and functionally distinct from mammary tissue macrophages (MTMs). TAMs express the adhesion molecule Vcam1 and proliferate upon their differentiation from inflammatory monocytes, but do not exhibit an "alternatively activated" phenotype. TAM terminal differentiation depends on the transcriptional regulator of Notch signaling, RBPJ; and TAM, but not MTM, depletion restores tumor-infiltrating cytotoxic T cell responses and suppresses tumor growth. These findings reveal the ontogeny of TAMs and a discrete tumor-elicited inflammatory response, which may provide new opportunities for cancer immunotherapy.
1,053 citations
TL;DR: A molecular link between epithelial-to-mesenchymal transition (EMT) and CD8+ TIL immunosuppression and cancer progression is demonstrated and ZEB1 promotes metastasis through a heretofore unappreciated cell non-autonomous mechanism, and subgroups of patients in whom malignant progression is driven by EMT activators may respond to treatment with PD-L1 antagonists.
Abstract: Immunosuppression of tumour-infiltrating lymphocytes (TIL) is a common feature of advanced cancer, but its biological basis has remained obscure. We demonstrate here a molecular link between epithelial-to-mesenchymal transition (EMT) and CD8(+) TIL immunosuppression, two key drivers of cancer progression. We show that microRNA-200 (miR-200), a cell-autonomous suppressor of EMT and metastasis, targets PD-L1. Moreover, ZEB1, an EMT activator and transcriptional repressor of miR-200, relieves miR-200 repression of PD-L1 on tumour cells, leading to CD8(+) T-cell immunosuppression and metastasis. These findings are supported by robust correlations between the EMT score, miR-200 levels and PD-L1 expression in multiple human lung cancer datasets. In addition to revealing a link between EMT and T-cell dysfunction, these findings also show that ZEB1 promotes metastasis through a heretofore unappreciated cell non-autonomous mechanism, and suggest that subgroups of patients in whom malignant progression is driven by EMT activators may respond to treatment with PD-L1 antagonists.
737 citations
TL;DR: TIGIT expression identifies a Treg cell subset that demonstrates selectivity for suppression of Th1 and Th17 cell but not Th2 cell responses.
636 citations
TL;DR: In this article, a continuous-flow culture apparatus is used to maintain proliferating cancer cells in low-glucose conditions, demonstrating that mitochondrial oxidative phosphorylation (OXPHOS) is essential for optimal proliferation in these conditions; the most sensitive cell lines are defective in OXPHOS upregulation and may therefore be sensitive to current antidiabetic drugs that inhibit OPHOS.
Abstract: New apparatus is used to maintain proliferating cancer cells in low-glucose conditions, demonstrating that mitochondrial oxidative phosphorylation (OXPHOS) is essential for optimal proliferation in these conditions; the most sensitive cell lines are defective in OXPHOS upregulation and may therefore be sensitive to current antidiabetic drugs that inhibit OXPHOS. Using a new continuous-flow culture apparatus called Nutrostat, designed to ensure constant and controlled extracellular nutrient levels, David Sabatini and colleagues screened cancer cell lines for genes important when cells experience low glucose levels. They found that the ability of cells to increase mitochondrial oxidative phosphorylation under conditions of low glucose was crucial. Cancer cells unable to do so due to impaired glucose utilization or mitochondrial DNA mutations were particularly sensitive to a class of compounds, biguanides, which are in use to treat diabetes. These findings may lead to new therapeutic applications of these drugs to treat tumours displaying such defects. As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues1,2, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here we developed a continuous-flow culture apparatus (Nutrostat) for maintaining proliferating cells in low-nutrient media for long periods of time, and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low-glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNA interference (RNAi) screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the OXPHOS upregulation that is normally caused by glucose limitation as a result of either mitochondrial DNA (mtDNA) mutations in complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, antidiabetic drugs that inhibit OXPHOS3,4, when cancer cells are grown in low glucose or as tumour xenografts. Notably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of complex I function5. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors.
547 citations
TL;DR: An overview of regulatory mechanisms and important developmental processes controlled by TAZ and YAP is provided and it is outlined that TAZ/YAP activity is regulated by mechanical and cytoskeletal cues as well as by various extracellular factors.
Abstract: Studies over the past 20 years have defined the Hippo signaling pathway as a major regulator of tissue growth and organ size. Diverse roles for the Hippo pathway have emerged, the majority of which in vertebrates are determined by the transcriptional regulators TAZ and YAP (TAZ/YAP). Key processes regulated by TAZ/YAP include the control of cell proliferation, apoptosis, movement and fate. Accurate control of the levels and localization of these factors is thus essential for early developmental events, as well as for tissue homeostasis, repair and regeneration. Recent studies have revealed that TAZ/YAP activity is regulated by mechanical and cytoskeletal cues as well as by various extracellular factors. Here, I provide an overview of these and other regulatory mechanisms and outline important developmental processes controlled by TAZ and YAP.
539 citations
TL;DR: It is found that the amount of protein synthesized per hour in HSCs in vivo was lower than in most other haematopoietic cells, even if it was controlled for differences in cell cycle status or forced H SCs to undergo self-renewing divisions.
Abstract: Many aspects of cellular physiology remain unstudied in somatic stem cells. For example, there are almost no data on protein synthesis in any somatic stem cell. We found that the amount of protein synthesized per hour in haematopoietic stem cells (HSCs) in vivo was lower than in most other haematopoietic cells, even if we controlled for differences in cell cycle status or forced HSCs to undergo self-renewing divisions. Reduced ribosome function in Rpl24Bst/+ mice further reduced protein synthesis in HSCs and impaired HSC function. Pten deletion increased protein synthesis in HSCs but also reduced HSC function. Rpl24Bst/+ cell-autonomously rescued the effects of Pten deletion in HSCs, blocking the increase in protein synthesis, restoring HSC function, and delaying leukaemogenesis. Pten deficiency thus depletes HSCs and promotes leukaemia partly by increasing protein synthesis. Either increased or decreased protein synthesis impairs HSC function.
492 citations
TL;DR: It is shown that a major fraction of macrophages unexpectedly undergo cell division locally within AT, as detected by Ki67 expression and 5-ethynyl-2'-deoxyuridine incorporation, and in addition to blood monocyte recruitment, in situ proliferation driven by MCP-1 is an important process by which macrophage accumulate in the VAT in obesity.
485 citations
TL;DR: It is found that both cell division and hypermutation are directly proportional to the amount of antigen captured and presented by GC B cells to follicular helper T cells in the light zone.
Abstract: During immune responses, B lymphocytes clonally expand and undergo secondary diversification of their immunoglobulin genes in germinal centres (GCs). High-affinity B cells are expanded through iterative interzonal cycles of division and hypermutation in the GC dark zone followed by migration to the GC light zone, where they are selected on the basis of affinity to return to the dark zone. Here we combine a transgenic strategy to measure cell division and a photoactivatable fluorescent reporter to examine whether the extent of clonal expansion and hypermutation are regulated during interzonal GC cycles. We find that both cell division and hypermutation are directly proportional to the amount of antigen captured and presented by GC B cells to follicular helper T cells in the light zone. Our data explain how GC B cells with the highest affinity for antigen are selectively expanded and diversified.
484 citations
TL;DR: It is concluded that ROS signaling is an emerging key regulator of multiple stem cell populations and the implications for reprogramming and stem cell ageing are discussed.
Abstract: An appropriate balance between self-renewal and differentiation is crucial for stem cell function during both early development and tissue homeostasis throughout life. Recent evidence from both pluripotent embryonic and adult stem cell studies suggests that this balance is partly regulated by reactive oxygen species (ROS), which, in synchrony with metabolism, mediate the cellular redox state. In this Primer, we summarize what ROS are and how they are generated in the cell, as well as their downstream molecular targets. We then review recent findings that provide molecular insights into how ROS signaling can influence stem cell homeostasis and lineage commitment, and discuss the implications of this for reprogramming and stem cell ageing. We conclude that ROS signaling is an emerging key regulator of multiple stem cell populations.
468 citations
TL;DR: It is shown that a cell-autonomous loss in self-renewal occurs via alterations in fibroblast growth factor receptor-1, p38α and p38β mitogen-activated protein kinase signaling in satellite cells from aged mice, and it is demonstrated that pharmacological manipulation of these pathways can ameliorate age-associated self-Renewal defects.
Abstract: Skeletal muscle aging results in a gradual loss of skeletal muscle mass, skeletal muscle function and regenerative capacity, which can lead to sarcopenia and increased mortality. Although the mechanisms underlying sarcopenia remain unclear, the skeletal muscle stem cell, or satellite cell, is required for muscle regeneration. Therefore, identification of signaling pathways affecting satellite cell function during aging may provide insights into therapeutic targets for combating sarcopenia. Here, we show that a cell-autonomous loss in self-renewal occurs via alterations in fibroblast growth factor receptor-1, p38α and p38β mitogen-activated protein kinase signaling in satellite cells from aged mice. We further demonstrate that pharmacological manipulation of these pathways can ameliorate age-associated self-renewal defects. Thus, our data highlight an age-associated deregulation of a satellite cell homeostatic network and reveal potential therapeutic opportunities for the treatment of progressive muscle wasting.
TL;DR: The importance of BTK in various signalling pathways in the context of its therapeutic inhibition is highlighted and molecular effects that cannot be explained by the classic role ofBTK in BCR signalling are highlighted.
Abstract: Bruton's tyrosine kinase (BTK) is a key component of B cell receptor (BCR) signalling and functions as an important regulator of cell proliferation and cell survival in various B cell malignancies. Small-molecule inhibitors of BTK have shown antitumour activity in animal models and, recently, in clinical studies. High response rates were reported in patients with chronic lymphocytic leukaemia and mantle cell lymphoma. Remarkably, BTK inhibitors have molecular effects that cannot be explained by the classic role of BTK in BCR signalling. In this Review, we highlight the importance of BTK in various signalling pathways in the context of its therapeutic inhibition.
TL;DR: It was found that mesothelin-targeted CAR T cells administered directly to the lung outpaced those administered systemically by both efficacy and persistence in an orthotopic model of lung cancer, and regional delivery could improve both the efficacy and efficiency of solid tumor immunotherapy.
Abstract: Translating the recent success of chimeric antigen receptor (CAR) T cell therapy for hematological malignancies to solid tumors will necessitate overcoming several obstacles, including inefficient T cell tumor infiltration and insufficient functional persistence. Taking advantage of an orthotopic model that faithfully mimics human pleural malignancy, we evaluated two routes of administration of mesothelin-targeted T cells using the M28z CAR. We found that intrapleurally administered CAR T cells vastly outperformed systemically infused T cells, requiring 30-fold fewer M28z T cells to induce long-term complete remissions. After intrapleural T cell administration, prompt in vivo antigen-induced T cell activation allowed robust CAR T cell expansion and effector differentiation, resulting in enhanced antitumor efficacy and functional T cell persistence for 200 days. Regional T cell administration also promoted efficient elimination of extrathoracic tumor sites. This therapeutic efficacy was dependent on early CD4(+) T cell activation associated with a higher intratumoral CD4/CD8 cell ratios and CD28-dependent CD4(+) T cell-mediated cytotoxicity. In contrast, intravenously delivered CAR T cells, even when accumulated at equivalent numbers in the pleural tumor, did not achieve comparable activation, tumor eradication, or persistence. The ability of intrapleurally administered T cells to circulate and persist supports the concept of delivering optimal CAR T cell therapy through "regional distribution centers." On the basis of these results, we are opening a phase 1 clinical trial to evaluate the safety of intrapleural administration of mesothelin-targeted CAR T cells in patients with primary or secondary pleural malignancies.
TL;DR: It is observed that copy number alteration detection could identify the genomic region that enabled cell survival under selective conditions (i.c. ricin selection) and this resource enables novel and more informed studies with 293 cells, and the sequenced cell lines are distributed.
Abstract: The HEK293 human cell lineage is widely used in cell biology and biotechnology. Here we use whole-genome resequencing of six 293 cell lines to study the dynamics of this aneuploid genome in response to the manipulations used to generate common 293 cell derivatives, such as transformation and stable clone generation (293T); suspension growth adaptation (293S); and cytotoxic lectin selection (293SG). Remarkably, we observe that copy number alteration detection could identify the genomic region that enabled cell survival under selective conditions (i.c. ricin selection). Furthermore, we present methods to detect human/vector genome breakpoints and a user-friendly visualization tool for the 293 genome data. We also establish that the genome structure composition is in steady state for most of these cell lines when standard cell culturing conditions are used. This resource enables novel and more informed studies with 293 cells, and we will distribute the sequenced cell lines to this effect.
TL;DR: The studies identify lincRNA-p21 as a novel regulator of cell proliferation and apoptosis and suggest that this lncRNA could serve as a therapeutic target to treat atherosclerosis and related cardiovascular disorders.
Abstract: Background—Long noncoding RNAs (lncRNAs) have recently been implicated in many biological processes and diseases. Atherosclerosis is a major risk factor for cardiovascular disease. However, the functional role of lncRNAs in atherosclerosis is largely unknown. Methods and Results—We identified lincRNA-p21 as a key regulator of cell proliferation and apoptosis during atherosclerosis. The expression of lincRNA-p21 was dramatically downregulated in atherosclerotic plaques of ApoE−/− mice, an animal model for atherosclerosis. Through loss- and gain-of-function approaches, we showed that lincRNA-p21 represses cell proliferation and induces apoptosis in vascular smooth muscle cells and mouse mononuclear macrophage cells in vitro. Moreover, we found that inhibition of lincRNA-p21 results in neointimal hyperplasia in vivo in a carotid artery injury model. Genome-wide analysis revealed that lincRNA-p21 inhibition dysregulated many p53 targets. Furthermore, lincRNA-p21, a transcriptional target of p53, feeds back to...
TL;DR: It is determined that the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) is uniformly depleted in over six hundred ccRCC tumours examined, distinguishing FBP1 from previously identified tumour suppressors that are not consistently mutated in all tumours.
Abstract: Fructose-1,6-bisphosphatase is shown to be depleted in clear cell renal cell carcinoma (ccRCC) and inhibits ccRCC progression by antagonizing glycolytic flux in renal tubular epithelial cells and by restraining cell proliferation, glycolysis, and the pentose phosphate pathway in von Hippel–Lindau-protein-deficient ccRCC cells by blocking hypoxia-inducible factor function. von Hippel–Lindau mutations occur in the vast majority of clear cell renal cell carcinoma (ccRCC) tumours, and these mutations result in stabilization of hypoxia-inducible factors. But this is not sufficient to cause the typical metabolic alterations found in ccRCC, nor sufficient for tumour formation. This paper reports that fructose-1,6-bisphosphatase (FBP1) was uniformly depleted in all of more than six hundred ccRCC tumours examined. FBP1 is shown to inhibit renal carcinoma progression through two different mechanisms. First, the enzyme antagonizes glycolytic flux in renal tubular epithelial cells, the presumptive ccRCC cell of origin, and this inhibits any potential 'Warburg effect'. Second, FBP1 restrains cell proliferation, glycolysis and the pentose phosphate pathway in ccRCC cells deficient in the von Hippel–Lindau protein (pVHL) by blocking nuclear hypoxia-inducible factor function. Clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer1, is characterized by elevated glycogen levels and fat deposition2. These consistent metabolic alterations are associated with normoxic stabilization of hypoxia-inducible factors (HIFs)3 secondary to von Hippel–Lindau (VHL) mutations that occur in over 90% of ccRCC tumours4. However, kidney-specific VHL deletion in mice fails to elicit ccRCC-specific metabolic phenotypes and tumour formation5, suggesting that additional mechanisms are essential. Recent large-scale sequencing analyses revealed the loss of several chromatin remodelling enzymes in a subset of ccRCC (these included polybromo-1, SET domain containing 2 and BRCA1-associated protein-1, among others)6,7,8,9, indicating that epigenetic perturbations are probably important contributors to the natural history of this disease. Here we used an integrative approach comprising pan-metabolomic profiling and metabolic gene set analysis and determined that the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1)10 is uniformly depleted in over six hundred ccRCC tumours examined. Notably, the human FBP1 locus resides on chromosome 9q22, the loss of which is associated with poor prognosis for ccRCC patients11. Our data further indicate that FBP1 inhibits ccRCC progression through two distinct mechanisms. First, FBP1 antagonizes glycolytic flux in renal tubular epithelial cells, the presumptive ccRCC cell of origin12, thereby inhibiting a potential Warburg effect13,14. Second, in pVHL (the protein encoded by the VHL gene)-deficient ccRCC cells, FBP1 restrains cell proliferation, glycolysis and the pentose phosphate pathway in a catalytic-activity-independent manner, by inhibiting nuclear HIF function via direct interaction with the HIF inhibitory domain. This unique dual function of the FBP1 protein explains its ubiquitous loss in ccRCC, distinguishing FBP1 from previously identified tumour suppressors that are not consistently mutated in all tumours6,7,15.
TL;DR: Results suggest that p53-regulated TUG1 is a growth regulator, which acts in part through control of HOXB7, thus participating in AKT and MAPK pathways.
Abstract: Recently, a novel class of transcripts, long non-coding RNAs (lncRNAs), is being identified at a rapid pace These RNAs have critical roles in diverse biological processes, including tumorigenesis Here we report that taurine-upregulated gene 1 (TUG1), a 71-kb lncRNA, recruiting and binding to polycomb repressive complex 2 (PRC2), is generally downregulated in non-small cell lung carcinoma (NSCLC) tissues In a cohort of 192 NSCLC patients, the lower expression of TUG1 was associated with a higher TNM stage and tumor size, as well as poorer overall survival (P<0001) Univariate and multivariate analyses revealed that TUG1 expression serves as an independent predictor for overall survival (P<0001) Further experiments revealed that TUG1 expression was induced by p53, and luciferase and chromatin immunoprecipitation (ChIP) assays confirmed that TUG1 was a direct transcriptional target of p53 TUG1 knockdown significantly promoted the proliferation in vitro and in vivo Moreover, the lncRNA-mediated regulation of the expression of HOX genes in tumorigenesis and development has been recently receiving increased attention Interestingly, inhibition of TUG1 could upregulate homeobox B7 (HOXB7) expression; ChIP assays demonstrated that the promoter of HOXB7 locus was bound by EZH2 (enhancer of zeste homolog 2), a key component of PRC2, and was H3K27 trimethylated This TUG1-mediated growth regulation is in part due to specific modulation of HOXB7, thus participating in AKT and MAPK pathways Together, these results suggest that p53-regulated TUG1 is a growth regulator, which acts in part through control of HOXB7 The p53/TUG1/PRC2/HOXB7 interaction might serve as targets for NSCLC diagnosis and therapy
TL;DR: It is highlighted how differing local milieu might drive context-specific TReg cell function and restoration of immune homeostasis, and how dysregulation of these processes can precipitate disease.
Abstract: Regulatory T (TReg) cells constitute an essential counterbalance to adaptive immune responses. Failure to maintain appropriate TReg cell numbers or function leads to autoimmune, malignant and immunodeficient conditions. Dynamic homeostatic processes preserve the number of forkhead box P3-expressing (FOXP3(+)) TReg cells within a healthy range, with high rates of cell division being offset by apoptosis under steady-state conditions. Recent studies have shown that TReg cells become specialized for different environmental contexts, tailoring their functions and homeostatic properties to a wide range of tissues and immune conditions. In this Review, we describe new insights into the molecular controls that maintain the steady-state homeostasis of TReg cells and the cues that drive TReg cell adaptation to inflammation and/or different locations. We highlight how differing local milieu might drive context-specific TReg cell function and restoration of immune homeostasis, and how dysregulation of these processes can precipitate disease.
TL;DR: This study demonstrates that the expression of many lncRNAs is up‐regulated in early liver development and that the fetal liver can be used to search for new diagnostic markers for HCC.
TL;DR: This study identifies supply‐driven feedforward activation of ribosomal protein synthesis as the key regulatory motif maximizing amino acid flux, and autonomously guiding a cell to achieve optimal growth in different environments, with implications for endogenous and synthetic design of microorganisms.
Abstract: Bacteria must constantly adapt their growth to changes in nutrient availability; yet despite large-scale changes in protein expression associated with sensing, adaptation, and processing different environmental nutrients, simple growth laws connect the ribosome abundance and the growth rate. Here, we investigate the origin of these growth laws by analyzing the features of ribosomal regulation that coordinate proteome-wide expression changes with cell growth in a variety of nutrient conditions in the model organism Escherichia coli. We identify supply-driven feedforward activation of ribosomal protein synthesis as the key regulatory motif maximizing amino acid flux, and autonomously guiding a cell to achieve optimal growth in different environments. The growth laws emerge naturally from the robust regulatory strategy underlying growth rate control, irrespective of the details of the molecular implementation. The study highlights the interplay between phenomenological modeling and molecular mechanisms in uncovering fundamental operating constraints, with implications for endogenous and synthetic design of microorganisms.
TL;DR: This dataset facilitates the linkage of genetic dependencies with specific cellular contexts (e.g., gene mutations or cell lineage) and developed and provided a bioinformatics tool to identify linear and nonlinear correlations between these features.
Abstract: Using a genome-scale, lentivirally delivered shRNA library, we performed massively parallel pooled shRNA screens in 216 cancer cell lines to identify genes that are required for cell proliferation and/or viability. Cell line dependencies on 11,000 genes were interrogated by 5 shRNAs per gene. The proliferation effect of each shRNA in each cell line was assessed by transducing a population of 11M cells with one shRNA-virus per cell and determining the relative enrichment or depletion of each of the 54,000 shRNAs after 16 population doublings using Next Generation Sequencing. All the cell lines were screened using standardized conditions to best assess differential genetic dependencies across cell lines. When combined with genomic characterization of these cell lines, this dataset facilitates the linkage of genetic dependencies with specific cellular contexts (e.g., gene mutations or cell lineage). To enable such comparisons, we developed and provided a bioinformatics tool to identify linear and nonlinear correlations between these features.
TL;DR: The results demonstrate the involvement of exosome-mediated communication in BMSC-induced proliferation, migration, survival, and drug resistance of MM cells.
TL;DR: Silver nanoparticles induce ROS accumulation and root growth promotion in Arabidopsis, suggesting that AgNPs acted as inhibitors of ethylene (ET) perception and could interfere with ET biosynthesis.
TL;DR: The results of this study indicate that pharmacological manipulation of STAT3 activity can be used to counteract the functional exhaustion of satellite cells in pathological conditions, thereby maintaining the endogenous regenerative response and ameliorating muscle-wasting diseases.
Abstract: The progressive loss of muscle regenerative capacity with age or disease results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions. The levels of STAT3, a downstream effector of IL-6, are also elevated with muscle wasting, and STAT3 has been implicated in the regulation of self-renewal and stem cell fate in several tissues. Here we show that IL-6-activated Stat3 signaling regulates satellite cell behavior, promoting myogenic lineage progression through myogenic differentiation 1 (Myod1) regulation. Conditional ablation of Stat3 in Pax7-expressing satellite cells resulted in their increased expansion during regeneration, but compromised myogenic differentiation prevented the contribution of these cells to regenerating myofibers. In contrast, transient Stat3 inhibition promoted satellite cell expansion and enhanced tissue repair in both aged and dystrophic muscle. The effects of STAT3 inhibition on cell fate and proliferation were conserved in human myoblasts. The results of this study indicate that pharmacological manipulation of STAT3 activity can be used to counteract the functional exhaustion of satellite cells in pathological conditions, thereby maintaining the endogenous regenerative response and ameliorating muscle-wasting diseases.
TL;DR: In insight into the relationship between tumor dissemination and metabolic attributes of human cancer stem cells, spheroid cells were found to be enriched for cells with cancer stem cell-like characteristics and contributed to tumor generation, progression and chemotherapy resistance.
Abstract: Cells with sphere forming capacity, spheroid cells, are present in the malignant ascites of patients with epithelial ovarian cancer (EOC) and represent a significant impediment to efficacious treatment due to their putative role in progression, metastasis and chemotherapy resistance. The exact mechanisms that underlie EOC metastasis and drug resistance are not clear. Understanding the biology of sphere forming cells may contribute to the identification of novel therapeutic opportunities for metastatic EOC. Here we generated spheroid cells from human ovarian cancer cell lines and primary ovarian cancer. Xenoengraftment of as few as 2000 dissociated spheroid cells into immune-deficient mice allowed full recapitulation of the original tumor, whereas >105 parent tumor cells remained non-tumorigenic. The spheroid cells were found to be enriched for cells with cancer stem cell-like characteristics such as upregulation of stem cell genes, self-renewal, high proliferative and differentiation potential, and high aldehyde dehydrogenase (ALDH) activity. Furthermore, spheroid cells were more aggressive in growth, migration, invasion, scratch recovery, clonogenic survival, anchorage-independent growth, and more resistant to chemotherapy in vitro. 13C-glucose metabolic studies revealed that spheroid cells route glucose predominantly to anaerobic glycolysis and pentose cycle to the detriment of re-routing glucose for anabolic purposes. These metabolic properties of sphere forming cells appear to confer increased resistance to apoptosis and contribute to more aggressive tumor growth. Collectively, we demonstrated that spheroid cells with cancer stem cell-like characteristics contributed to tumor generation, progression and chemotherapy resistance. This study provides insight into the relationship between tumor dissemination and metabolic attributes of human cancer stem cells and has clinical implications for cancer therapy.
TL;DR: It is proposed that reduced MPC activity is an important aspect of cancer metabolism, perhaps through altering the maintenance and fate of stem cells.
TL;DR: Preclinical proof of concept that anti-EGFR therapy can be used to target a subset of particularly aggressive MIBC tumors expressing basal cell markers is provided and diagnostic tools for identifying these tumors are provided.
Abstract: Muscle-invasive bladder carcinoma (MIBC) constitutes a heterogeneous group of tumors with a poor outcome. Molecular stratification of MIBC may identify clinically relevant tumor subgroups and help to provide effective targeted therapies. From seven series of large-scale transcriptomic data (383 tumors), we identified an MIBC subgroup accounting for 23.5% of MIBC, associated with shorter survival and displaying a basal-like phenotype, as shown by the expression of epithelial basal cell markers. Basal-like tumors presented an activation of the epidermal growth factor receptor (EGFR) pathway linked to frequent EGFR gains and activation of an EGFR autocrine loop. We used a 40-gene expression classifier derived from human tumors to identify human bladder cancer cell lines and a chemically induced mouse model of bladder cancer corresponding to human basal-like bladder cancer. We showed, in both models, that tumor cells were sensitive to anti-EGFR therapy. Our findings provide preclinical proof of concept that anti-EGFR therapy can be used to target a subset of particularly aggressive MIBC tumors expressing basal cell markers and provide diagnostic tools for identifying these tumors.
TL;DR: By transcriptional profiling analysis, it is shown that, although both monocyte and tissue-derived AAMs expressed high levels of Arg1, Chi3l3, and Retnla, only monocyte-derivedAAMs up-regulated Raldh2 and PD-L2, and monocytes' properties associated with immune regulation may depend on the distinct lineage of these cells.
TL;DR: GAS5 expression was markedly downregulated in gastric cancer tissues, and associated with larger tumor size and advanced pathologic stage, and downregulation of endogenous GAS5 could promote cell proliferation.
Abstract: Gastric cancer is the second leading cause of cancer death and remains a major clinical challenge due to poor prognosis and limited treatment options. Long noncoding RNAs (lncRNAs) have emerged recently as major players in tumor biology and may be used for cancer diagnosis, prognosis, and potential therapeutic targets. Although downregulation of lncRNA GAS5 (Growth Arrest-Specific Transcript) in several cancers has been studied, its role in gastric cancer remains unknown. Our studies were designed to investigate the expression, biological role and clinical significance of GAS5 in gastric cancer. Expression of GAS5 was analyzed in 89 gastric cancer tissues and five gastric cancer cell lines by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Over-expression and RNA interference (RNAi) approaches were used to investigate the biological functions of GAS5. The effect of GAS5 on proliferation was evaluated by MTT and colony formation assays, and cell apoptosis was evaluated by hochest stainning. Gastric cancer cells transfected with pCDNA3.1 -GAS5 were injected into nude mice to study the effect of GAS5 on tumorigenesis in vivo. Protein levels of GAS5 targets were determined by western blot analysis. Differences between groups were tested for significance using Student’s t-test (two-tailed). We found that GAS5 expression was markedly downregulated in gastric cancer tissues, and associated with larger tumor size and advanced pathologic stage. Patients with low GAS5 expression level had poorer disease-free survival (DFS; P = 0.001) and overall survival (OS; P < 0.001) than those with high GAS5 expression. Further multivariable Cox regression analysis suggested that decreased GAS5 was an independent prognostic indicator for this disease (P = 0.006, HR = 0.412; 95%CI = 2.218–0.766). Moreover, ectopic expression of GAS5 was demonstrated to decrease gastric cancer cell proliferation and induce apoptosis in vitro and in vivo, while downregulation of endogenous GAS5 could promote cell proliferation. Finally, we found that GAS5 could influence gastric cancer cells proliferation, partly via regulating E2F1 and P21 expression. Our study presents that GAS5 is significantly downregulated in gastric cancer tissues and may represent a new marker of poor prognosis and a potential therapeutic target for gastric cancer intervention.
TL;DR: The significance of CaM and interconnected CaM-regulated systems for the physiology of cancer cells including tumor stem cells, and processes required for tumor progression such as growth, tumor-associated angiogenesis and metastasis are highlighted.