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Paediatric bone and joint infections can be associated with devastating consequences for the growing child. The diagnosis is challenging, requiring experienced clinical examination with adjunct diagnostic tests to aid the distinction between a multitude of differential diagnoses which includes transient synovitis, fracture, neoplasia, rheumatological conditions, blood disorders and infection. Emergent diagnosis is required to prevent consequences such as sepsis, chronic infection, angular deformity and disruption of longitudinal bone growth. The clinical presentation of bone and joint infections in children is varied and includes pain, erythema and swelling, fever, reduced range of movement and the inability to weight bear. Blood and tissue samples should be obtained, if possible, prior to commencing antimicrobial therapy in order to secure the best chance of identifying a causative organism and guide treatment. However, this should not delay treatment. Various imaging modalities can be helpful. Whilst there is some variation depending on the child's age, Staphylococcus aureus is the commonest causative organism in both septic arthritis and osteomyelitis. Septic arthritis and osteomyelitis in children should be treated jointly by paediatricians and orthopaedic surgeons, with input from the wider multi-disciplinary team. Trends towards reduced rates of surgical intervention and shorter antibiotic courses have been evident over recent decades. In this article we present a review of the continuously evolving concepts for the management of paediatric bone and joint infections. [ABSTRACT FROM AUTHOR]

Background: . This study performed to investigate the incidence of growth arrest such as leg length discrepancy (LLD) and ankle joint angular deformity and its risk factors after physeal fracture of the distal tibia in children and adolescents.Materials and Methods: . Consecutive 78 patients (mean age 11.4 ± 2.0 years; mean follow-up period 2.0 ± 1.2 years) treated for the distal tibia physeal fracture were included. All patients underwent preoperative ankle radiographs, three-dimensional computed tomography (CT) scans, and postoperative follow-up teleradiogram. Patients were divided into two groups according to the LLD and the difference of lateral distal tibial angle (LDTA) with the contralateral limb as follows: Group 1 (growth arrest), patients with LLD ≥ 1cm or difference of LDTA ≥ 5°; Group 2 (normal growth), patients with LLD < 1cm and difference of LDTA < 5°.Results: . The overall incidence of growth arrest was 12.8% (10 of 78). The mean displacement measured using CT scan was 4.4 ± 3.2 mm (range, 0.8-14.9). Of the total 78 fractures, 65 were treated surgically and 13 fractures were treated conservatively. The initial fracture displacement was significantly different between the two groups (p<0.001). However, there were no statistically significant differences between the two groups with respect to other factors. Initial displacement was the only significant risk factor for growth arrest (p<0.003). The cutoff values of initial displacement between the two groups were 5.2mm.Conclusions: . This study showed that degree of initial displacement was the only significant risk factor for growth arrest after physeal fracture of the distal tibia in children and adolescents. Therefore, physicians should consider the possibility of growth arrest for patients with severely displaced physeal fractures of the distal tibia. [ABSTRACT FROM AUTHOR]

The growth plate is a key component of developing bones. The growth plate, or physis, is a highly ordered structure and is composed of discrete layers. Each layer has a specific function that contributes to the growing bone. As a result of this, each layer also has the potential for problems to occur, leading to recognized diseases and syndromes. An understanding of the physis, along with diseases and disorders that can affect its function, is of great importance for the practising orthopaedic surgeon. The anatomy and disorders of the growth plate is also a common basic science viva topic in the FRCS examination. The aim of this article is to provide a sound understanding of the layered structure and function of the physis, with a description of the developmental processes and potential disorders of each layer. Trauma to the growth plate and subsequent growth arrest will also be reviewed. [ABSTRACT FROM AUTHOR]

Ex vivo expansion of hematopoietic progenitors is considered as an attractive tool to increase the number of stem and progenitor cells (HSPCs) for cell therapy. The efficacy of ex vivo expansion is strongly depends on the feeder cell activity to mimic hematopoietic microenvironment. Here we demonstrated, that combination of mitomycin C-induced growth arrest and tissue-related O 2 (physiological hypoxia) modulated stromal capacity of adipose tissue derived stromal cells (ASCs). Growth arrest did not affect viability, stromal phenotype and multilineage potential of ASCs permanently expanded at tissue-related O 2. Meanwhile, the PCR analysis revealed an up-regulation of genes, encoded molecules of cell–cell (ICAM1 , HCAM/CD44) and cell–matrix adhesion (ITGs), extracellular matrix production (COLs) and remodeling (MMPs , HAS1) in growth-arrested ASCs at physiological hypoxia in comparison with ambient O 2 (20%). The number of ICAM-1 positive ASCs was increased under low O 2 as well. These alterations contributed into the ex vivo expansion of cord blood HSPCs providing the preferential production of primitive HSPCs. The number of cobblestone area forming cell (CAFC) colonies was 1.5-fold higher at physiological hypoxia (p < 0.05). CAFCs considered as long-term culture-initiating cells (LTC-IC) known to support long-term hematopoiesis restoration in vivo. The presented data may be applicable in the development of upscale protocols of HSPC expansion. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is the third most diagnosed cancer in the U.S and is highly associated with daily diet and eating patterns. A plant-based diet rich in phytochemicals is known to be protective against the initiation and progression of CRC. The hop plant, a key ingredient in beer, contains diverse bioactive compounds that possess biological benefits in tumorigenesis. Xanthohumol (XN) is the most abundant prenylated flavonoid; several derivatives including isoxanthohumol (IXN), 8-prenylnaringenin (8-PN), and tetrahydroxanthohumol (TXN) have also been identified. The current study aimed to test the effect of these compounds in suppressing proliferation and to elucidate their anti-cancer mechanisms using human adenocarcinoma CRC cells. The results indicated all four hop compounds to significantly suppress the proliferation of multiple CRC cell lines. We selected TXN and XN for further study. Flow cytometry analysis indicated both to lead to significant induction of S -phase and G2/M-phase arrest. An apoptotic assay showed increases of early and late apoptosis. Western blot data indicated significant decreases of cyclin A and CDK2, increase of poly (ADP-ribose) polymerase (PARP) cleavage, and increase of CCAAT-enhancer-binding protein homologous protein (CHOP), activating transcription factor 4 (ATF4), and inositol requiring enzyme 1α (IRE1α). In addition, dose-dependent increases were observed in intracellular reactive oxygen species (ROS), mitochondrial dysfunction, and LC3II/LC3I ratio. Taken together, our study proposes an anti-cancer mechanism of TXN and XN that involves induction of ROS release, ER stress, mitochondrial dysfunction, apoptosis, and autophagy in human CRC cells. [ABSTRACT FROM AUTHOR]

Mammalian interferon-induced proteins with tetratricopeptide repeats (IFITs) play important roles in many cellular processes and host innate immune response to viruses. However, the functions of IFIT proteins in birds are largely unknown. Here, we first describe that the only one avian IFIT protein is orthologous to ancestor of mammalian IFITs. We find that the predicted structure of duck AvIFIT protein is similar to that of human IFIT5. We also find that duck AvIFIT protein shows antiviral activity to a broad range of specific RNA and DNA viruses like mammalian IFIT proteins. Further analysis indicates that overexpression of duck AvIFIT protein in DF1 cells leads to a remarkable accumulation of cells at G1/S transition associated with growth arrest and may promote apoptosis. Moreover, duck AvIFIT binds to nucleoprotein (NP) of H5N1 influenza virus and upregulates the expression of genes involving the IFN pathway in DF1 cells. In summary, our findings support that duck AvIFIT protein plays critical role in host immune response to viruses, at least H5N1 virus, through affecting function of viral NP protein, magnifying the IFN signaling and arresting cell growth. [ABSTRACT FROM AUTHOR]

Cyanobacteria are microbes with high photosynthetic efficiencies, making them a promising target for the production of sustainable bioproducts directly from solar energy and carbon dioxide. The most common efforts to increase cyanobacterial bioproduction involve diverting cellular resources away from cellular biomass and towards a heterologous pathway, for example through nutrient starvation or knockout of genes in competing metabolic pathways. Here we show that an inducible cell growth arrest switch can be used to increase the partitioning of carbon to an engineered sucrose sink. Specifically, we show that overexpression of Regulator of Phycobilisome-Associated B (RpaB), an essential response regulator in Synechococccous elongatus PCC 7942 , allows for inducible arrest of cell growth and is associated with a > 2-fold higher specific productivity of a heterologous sucrose secretion pathway. Finally, we show that sucrose export can partially relieve photosynthetic feedback inhibition imposed by the RpaB dependent growth arrest, allowing sucrose-secreting strains to maintain higher photosynthetic efficiencies. This work provides a novel conceptual framework for improving photosynthetic productivity and cyanobacterial bioproduction. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) may be a critical risk factor for metabolic disorders including obesity and diabetes. Sulforaphane is known to inhibit adipocyte differentiation and induce adipocyte lipolysis. This study sought to investigate the possible effects of sulforaphane on BPA-induced adipocyte differentiation in 3T3-L1 cells. During the preadipocytes differentiation process, sulforaphane suppressed the expression of early adipogenic factors, PPARγ and C/EBPα, induced by BPA in 3T3-L1 cells. Based on cell cycle analysis, sulforaphane mediated the inhibition of mitotic clonal expansion via cell cycle arrest at the G0/G1 phase. The compound inhibited cell cycle progression by suppressing cell cycle regulators such as cyclin D1 and pRb and by increasing p21 and p27, cell cycle inhibitors. Moreover, sulforaphane activated phosphorylation of AMPK and ACC and decreased that of ERK1/2 and Akt. Sulforaphane exerts inhibitory effects on BPA-induced adipocyte differentiation in 3T3-L1 cells. Sulforaphane could be adipogenic properties for improving environmental pollutants. [ABSTRACT FROM AUTHOR]

In addition to its conventional role for cell proliferation and survival, the Raf/MEK/Extracellular signal-regulated kinase (ERK) pathway can also induce growth arrest and death responses, if aberrantly activated. Here, we determined a molecular basis of ERK1/2 signaling that underlies these growth inhibitory physiological outputs. We found that overexpression of ERK1 or ERK2 switches ΔRaf-1:ER-induced growth arrest responses to caspase-dependent apoptotic death responses in different cell types. These death responses, however, were reverted to growth arrest responses upon titration of cellular phospho-ERK1/2 levels by the MEK1/2 inhibitor AZD6244. These data suggest that a cellular threshold for active ERK1/2 levels exists and affects the cell fate between death and growth arrest. We also found that death-mediating ability of ERK2 is abolished by the catalytic site-disabling Lys52Arg replacement or significantly attenuated by the F-site recruitment site-disabling Tyr261Asn replacement, although unaffected by the mutations that disable the common docking groove or the dimerization interface. Therefore, ERK1/2 mediates death signaling dependently of kinase activity and specific physical interactions. Intriguingly, Tyr261Asn-replaced ERK2 could still mediate growth arrest signaling, further contrasting the molecular basis of ERK1/2-mediated growth arrest and death signaling. These data reveal a mechanism underlying the role of ERK1/2 as a focal point of Raf/MEK/ERK-mediated growth arrest and death signaling. [ABSTRACT FROM AUTHOR]

Human induced pluripotent stem cells (iPSC) have the potential to radically reduce the number of animals used in both toxicological science and disease elucidation. One initial obstacle culturing iPSC is that they require daily medium exchange. This study attempts to clarify why and propose some practical solutions. Two iPSC lineages were fed at different intervals in a full growth area (FGA) or a restricted growth area (RGA). The FGA consisted of a well coated with Matrigel™ and the RGA consisted of a coated coverslip placed in a well. Glucose, lactate, extracellular pH and cell cycle phases were quantified. Without daily feeding, FGA cultured iPSC had significantly reduced growth rates by day 2 and began to die by day 3. In contrast, RGA cultured cells grew to confluence over 3 days. Surprisingly, glucose was not exhausted under any condition. However, extracellular pH reached 6.8 after 72 h in FGA cultures. Artificially reducing medium pH to 6.8 also inhibited glycolysis and initiated an increase in G0/G1 phase of the cell cycle, while adding an additional 10 mM bicarbonate to the medium increased glycolysis rates. This study demonstrates that iPSC are highly sensitive to extracellular acidification, a likely limiting factor in maintenance of proliferative and pluripotent status. Culturing iPSC in RGA prevents rapid extracellular acidification, while still maintaining pluripotency and allowing longer feeding cycles. [ABSTRACT FROM AUTHOR]

Irinotecan (CPT-11) is an effective chemotherapeutic agent widely used to treat different cancers. Otherwise, the liposomal delivery of anti-tumor agents has been shown to be a promising strategy. The aim of this study has been to analyze the effect of liposomal CPT-11 (CPT-11lip) on two human cell lines (Hs68 and HeLa) to establish the suitability of this CPT-11 nanocarrier. We have demonstrated the highest uptake of CPT-11lip in comparison with that of CPT-11sol, in lactate buffer, and that CPT-11lip was internalized in the cells through an endocytic process whereas CPT-11sol does so by passive diffusion. CPT-11lip was not cytotoxic to normal fibroblast Hs68 cells, but induced a massive apoptosis accompanied by cell senescence in HeLa cells. CPT-11lip treatment modified the morphology of HeLa cells, induced different cell cycle alterations and accumulated into lysosomes in both cell lines. In particular, CPT-11lip treatment showed that surviving HeLa cells remained in a state of senescence whereas only a temporal growth arrest was induced in Hs68 cells. Results of RT-PCR indicated that the different responses in Hs68 (survival) and HeLa cells (apoptotic death), seemed to be induced by a p53- and p53- independent mechanism, respectively. An analysis of DNA damage also determined that released CPT-11 from liposomes was able to reach the nucleus and exert a genotoxic effect in both cell lines, which was repaired in Hs68 but not in HeLa cells. All results indicate that phospholipid-cholesterol liposomes possess optimum properties for CPT-11 delivery, being biocompatible and selectively cytotoxic against HeLa tumorigenic cells. [ABSTRACT FROM AUTHOR]

Leukemia inhibitory factor (LIF) is a multifunctional highly glycosylated protein, synthesized and secreted in various body tissues. Besides the abundance in multiple organs, the molecular mechanism underlying the LIF interactions for cell survival and polarity is poorly understood. In the present study, high-resolution LC-MS/MS based LFQ approach identified 2083 proteins with the overall PSM as 16,032. This proteomics data reviles that LIF promotes the AKT-mTOR signaling pathway. It induces cell growth arrest by an intracellular pathways loop to increase the half-life of the cell. Bioinformatics-based enrichment analysis revealed the involvement of LIF interacting partners in cell survival through increasing the cell cycle length. The anti-proliferative effect of LIF was confirmed by BrdU, MTT and Caspase 3/7 assays and further validated by RT-qPCR. Till date to the best of our knowledge, this is the first study that elucidates LIF-mediated cascade of activation of MEK/ERK, Ras, mTOR, Hippo, and RAP1 pathways. This study further expands the repertoire of signaling pathways known to be subject to activation by LIF. These multiple involvements of pathways through autocrine-paracrine mediated cell cycle arrest additionally suggests a novel means for amplification of a growth arrest stimulus from LIF and its homolog's receptors. Biological significance Leukemia inhibitory factor (LIF) is the polyfunctional cytokine and highly pleiotropic member of the interleukin-6 family. It utilizes a receptor that consists of the LIF receptor b and gp130 and displays diverse effects on target cells. Despite well-known signal transduction mechanisms (JAK/STAT, MAPK, and PI3K) LIF also contains paradoxically opposing influences in several cell types which includes cellular stimulation, inhibition, proliferation, differentiation, and survival. LIF1 is also undergoing clinical trials as a driving force for the embryo implantation in the uterus in women who fail to become pregnant. As LIF can act on the broad spectrum of cell types, it is necessary to understand the basic response mechanism. The available non-canonical regulatory pathways and molecular mechanism associated with LIF are poorly explained. Therefore, we have performed the global proteome analysis of LIF-mediated autocrine-paracrine signaling. The obtained data were examined through advanced bioinformatics tools and LIF inducible changes in terms of pathways were elucidated. The result showed the involvement of cluster of proteins maintaining the Ras/Rap1/STAT3/Hippo pathways which modify the protein component machinery of core histone complexes. This report describes the involvement of proteins responsible for cell growth and progression and defines the LIF-mediated novel autocrine-paracrine signaling loop for cell growth arrest. [ABSTRACT FROM AUTHOR]

Fractures involving the physis account for up to one-third of paediatric fractures. It is also the structure which needs to be preserved to ensure normal growth. The relative strength of the physis changes with age and it becomes weaker as the child grows older, making physeal injuries more common in adolescence. It is important to understand the physeal anatomy and its relevance to different types of physeal injuries. Salter–Harris system is a clinically useful approach to classifying and describing physeal injuries. Each physeal injury should be treated as a distinct entity taking into account the patient's age, location of injury, type of injury, growth potential of the affected part, degree of displacement and time elapsed since injury. Its treatment ranges from conservative management to operative fixation. Manipulation of physeal fractures should be as gentle as possible to prevent growth plate damage leading to growth disturbances. These complications can be difficult and complex to manage. The management involves two phases: the first phase should ensure reduction, maintenance of reduction, and bone healing; the second phase involves monitoring the growth with long-term follow-up, to detect any deformities from growth arrests or disturbances. Counselling parents about the potential risk of future growth arrest and deformity is important. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the normal pattern of skeletal growth is vital to orthopaedic surgeons to guide appropriate management when problems such as leg length discrepancy occur in children. This review explores various techniques used to assess growth and examines methods to calculate growth remaining and their application to the timing of corrective surgery. [ABSTRACT FROM AUTHOR]

Introduction The proliferation and migration of dental pulp stem cells (DPSCs), a population comprised of dental pulp cells (DPCs), are important processes for pulp tissue repair. Dental pulp is exposed to changes in extracellular pH under various conditions, such as acidosis and exposure to caries-associated bacteria or a pulp capping agent. The objective of this study was to investigate the effects of extracellular pH on DPC proliferation and migration in vitro . Methods To evaluate the proliferation potency of DPCs in various extracellular pH conditions, 2 × 10 4 cells were seeded into 35-mm dishes. The following day, we changed to NaHCO 3 -free medium, which was adjusted to different extracellular pH levels. Results After 120 hours, DPCs cultured in media from a pH of 3.5 to 5.5 showed cell death, those cultured in conditions from a pH of 6.5 to 7.5 showed growth arrest or cell death, and those grown at a pH of 9.5 showed mild proliferation. The migratory activity of living DPCs was not affected by extracellular pH. For histologic analysis, human teeth possessing a small abscess in the coronal pulp chamber were sliced for histologic analysis. Proliferating cell nuclear antigen (PCNA) immunolocalization was used as an index of cell proliferation for the sections and cultured cells. Acidic extracellular pH conditions resulted in reduced numbers of PCNA-positive DPCs in the dishes. As for pulp tissue affected by a small abscess, a PCNA-negative pulp cell layer was observed in close proximity to the infectious lesion. Conclusions Together, these results suggest that an acidic extracellular pH condition is associated with DPC growth arrest or cell death. [ABSTRACT FROM AUTHOR]

Six polymers (HDPE/LDPE: High density/low density polyethylene, PET: Polyethylene terephthalate, PS: Polystyrene, PVC: Polyvinyl chloride and PP: Polypropylene) were converted to carbonised form by following standard protocol. The synthesized polymer origin carbon nanocomposites (POCNC) were characterized by proximate analysis, UV–Vis spectroscopy, scanning electron micrograph (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron micrograph (TEM) and fourier transform infrared spectroscopy (FTIR). This polymer origin carbon was taken separately in distilled and tap water to prepare five different concentrations (T 1 : 1 mg/L, T 2 : 3 mg/L, T 3 : 5 mg/L, T 4 : 7 mg/L, T 5 : 10 mg/L) and the same solution were used for mortality and developmental study of Culex quinquefasciatus. Results revealed that the LC 50 and LC 90 for larvae of Culex quinquefasciatus in distilled water follows as: PET < PVC < HDPE < LDPE < PP < PS and PET < PVC < HDPE < LDPE < PP < PS, respectively. On the other hand, the significant results with pupicidal activity of carbon nanocomposites from PET (F = 6.8, p < 0.029) and HDPE (F = 6.2, p < 0.035) in distilled water, and adulticidal activity with HDPE for both distilled (F = 8.2, p < 0.02) and tap-water (F = 8, p < 0.2) was recorded. Results also revealed that POCNC has no negative impact on non-target organisms (Oedogonium sp. and Allium cepa). Therefore, polymer origin carbon nanocomposites could be a valuable tool towards control of mosquito. [Display omitted] • Carbon nanocomposites were synthesized from waste plastics and characterised. • Mosquito larval mortality was assed (LC 50 and LC 90) under the exposure of carbon nanocomposites. • Significant pupicidal activity was exhibited by carbon nanocomposites from PET and HDPE. • Carbon nanocomposites does not exhibited any adverse effects on Oedogonium sp. and Allium cepa. [ABSTRACT FROM AUTHOR]

Extracellular matrices (ECM) present in our tissues play a significant role in maintaining tissue homeostasis through various physical and chemical cues such as topology, stiffness, and secretion of biochemicals. They are known to influence the behavior of resident stem cells. It is also known that ECM type and coating density on cell culture plates strongly influence in vitro cellular behavior. However, the influence of ECM protein coating on long-term mesenchymal stem cell expansion has not been studied yet. To address this gap, we cultured bone-marrow derived hMSCs for multiple passages on the tissue culture plastic plates coated with 25 μg/ml of various ECM proteins. We found that cells on plates coated with ECM proteins had much higher proliferation compared to the regular tissue culture plates. Further, gelatin-coated plates helped the cells to grow faster compared to collagen, fibronectin, and laminin coated plates. Additionally, the use of gelatin showed less size heterogeneity among the cells when expanded from passages 3 to 9 (P3 to P9). Gelatin also helped in maintaining cellular stiffness which was not observed across other ECM proteins. In summary, in this research, we have shown that gelatin which is the least expensive compared to other ECM proteins, provides a better platform for mesenchymal stem cell expansion. • Expansion of stem cells for clinical application is challenging. • Extracellular matrix protein coating of TCP supports a better expansion of hMSCs compared to commercially available TCP. • Gelatin, the inexpensive ECM protein, provides the highest expansion and maintains the differentiation potential of hMSCs. [ABSTRACT FROM AUTHOR]

Children with unoperated cleft palates have nearly normal growth of their faces whereas patients who have had early surgical repair often exhibit midfacial hypoplasia. Surgical repair is responsible for the underlying bone growth arrest but the mechanisms responsible for these surgical sequelae are poorly understood. We simulated the effect of cleft palate repair by raising a mucoperiosteal flap in the murine palate. Three-dimensional micro-CT reconstructions of the palate along with histomorphometric measurements, finite element (FE) modeling, immunohistochemical analyses, and quantitative RT-PCR were employed to follow the skeletal healing process. Inflammatory bone resorption was observed during the first few days after denudation, which destroyed the midpalatal suture complex. FE modeling was used to predict and map the distribution of strains and their associated stresses in the area of denudation and the magnitude and location of hydrostatic and distortional strains corresponded to sites of skeletal tissue destruction. Once re-epithelialization was complete and wound contracture subsided, the midpalatal suture complex reformed. Despite this, growth at the midpalatal suture was reduced, which led to palatal constriction and a narrowing of the dental arch. Thus the simple act of raising a flap, here mimicked by denuding the mucoperiosteum, was sufficient to cause significant destruction to the midpalatal suture complex. Although the bone and cartilage growth plates were re-established, mediolateral skeletal growth was nonetheless compromised and the injured palate never reached its full growth potential. These data strongly suggest that disruption of suture complexes, which have intrinsic growth potential, should be avoided during surgical correction of congenital anomalies. [ABSTRACT FROM AUTHOR]

Abstract: Protein kinase CK2 is a critical factor for the survival of cells. It is overexpressed in many cancer cells and provides protection against apoptosis in these cells. Inhibition of CK2 kinase activity in various cancer cells leads to apoptosis, which makes CK2 an attractive target for cancer therapy. Little is, however, known about CK2 inhibition in non-cancerous cells. Using the human retinal pigment epithelial cell line ARPE-19, we analyzed the formation of reactive oxygen species (ROS) and the ER stress signaling pathway after CK2 inhibition with CX-4945. Following CK2 inhibition, we did not find any significant generation of ROS in neither ARPE-19 non-cancer cells nor in HCT116 cancer cells. We found an induction of the ER stress pathway including the activation of eIF2α and ATF4 in both cell types. This activation was sufficient for ARPE-19 cells to cope with the ER stress. Furthermore, in contrast to HCT116 cancer cells, there was no induction of the pro-apoptotic transcription factor CHOP and no induction of apoptosis in the ARPE-19 cells. Overexpression of CHOP, however, induced apoptosis in ARPE-19 cells indicating that this step in the ER stress pathway is abrogated in normal cells compared to cancer cell. [Copyright &y& Elsevier]

Adaptive stress resistance in microbes is mostly attributed to the expression of stress response genes, including heat-shock proteins. Here, we report a response of E. coli to heat stress caused by degradation of an enzyme in the methionine biosynthesis pathway (MetA). While MetA degradation can inhibit growth, which by itself is detrimental for fitness, we show that it directly benefits survival at temperatures exceeding 50°C, increasing survival chances by more than 1,000-fold. Using both experiments and mathematical modeling, we show quantitatively how protein expression, degradation rates, and environmental stressors cause long-term growth inhibition in otherwise habitable conditions. Because growth inhibition can be abolished with simple mutations, namely point mutations of MetA and protease knockouts, we interpret the breakdown of methionine synthesis as a system that has evolved to halt growth at high temperatures, analogous to "thermal fuses" in engineering that shut off electricity to prevent overheating. [Display omitted] • Bacteria possess a fuse that protects them from dying at high temperatures • The fuse is an induced methionine-auxotrophy that causes growth inhibition • Growth-inhibited bacteria survive heat shocks 1,000-fold better than growing bacteria Schink et al. report that at high temperatures, bacteria cut off their methionine production, which halts biosynthesis and growth, similar to how a thermal fuse cuts off electricity in electrical devices. The resulting growth arrest protects bacteria should temperatures further rise beyond the habitable range. [ABSTRACT FROM AUTHOR]

Purpose: To characterize the complications that occur at the index metacarpophalangeal (MCP) joint following pollicization and to identify the blood supply of the index MCP joint. Methods: Eighty-five pollicized digits in 74 patients (1974–2007) were followed after surgery and had documented clinical examinations and radiographs to evaluate physeal arrest, nonunion at the pollicized digit base, and instability of the new carpometacarpal joint at a minimum of 2 years following surgery. Results: Proximal phalanx physeal arrest was the most common complication. Radiographic nonunion at the juncture of the index metacarpal head and base occurred with and without instability. Twenty-one of 85 pollicized digits showed radiographic evidence of physeal arrest, 12 of which were complete and 9 partial. No clinical factor was found to significantly correlate with a physeal arrest, although the 9 patients with the diagnosis of Holt-Oram syndrome trended toward a higher percentage, with 6 digits in 5 patients with Holt-Oram syndrome showing this complication. Twenty pollicized MCP joints did not have bony union to the base of the index metacarpal, but only 3 were clinically unstable and required surgical stabilization. Ten pollicized digits developed some degree of instability and subluxation at the new carpometacarpal joint, but only one required surgical intervention. In recent cases, a search for the blood supply to the MCP joint has demonstrated a consistent vessel deep to the interosseous muscles that arborizes on the volar metacarpal neck. Our surgical technique has evolved to preserve this vessel whenever possible. Conclusions: Our complications are most likely due to technical factors. Careful dissection of the index MCP joint during pollicization should help reduce physeal growth arrest. Patients with Holt-Oram syndrome might have an increased risk of growth arrest. However, the majority of patients did not require secondary surgery and have good function. Type of study/level of evidence: Therapeutic IV. [Copyright &y& Elsevier]

Abstract: Physeal fractures account for approximately one third of all childhood fractures. Growth arrest is a serious complication of these injuries which, if not managed correctly, can lead to angular deformity, limb length discrepancy, or both. This in turn may cause pain, loss of function and disability. The article reviews the evaluation of a child with suspected traumatic physeal growth arrest including patient history, physical examination and imaging strategies for the early detection of physeal growth arrest and measurement of limb length discrepancy. Various anatomical classifications of physeal growth arrest are also presented. Finally, we discuss an approach to the management of a child with confirmed traumatic physeal growth arrest depending on the nature of the arrest and limb deformity. [Copyright &y& Elsevier]

Abstract: The product of the SALL2 protein p150Sal2 is a multi-zinc finger transcription factor with growth arrest and proapoptotic functions that overlap those of p53. Its DNA-binding properties are unknown. We have used a modified SELEX procedure with purified p150Sal2 and a pool of oligonucleotides of random sequence to identify those that are bound preferentially by p150Sal2. The consensus sequence for optimal binding in vitro is GGG(T/C)GGG, placing p150Sal2 among a large group of GC box-binding proteins including the Sp1 family of transcription factors. A triple zinc finger motif in p150Sal2 similar to that in Sp1 is required for DNA binding. p150Sal2 and Sp1 show evidence of co-operative binding in vitro and of interaction in vivo. p150Sal2, a known activator of the CDK inhibitor p21Cip1/Waf1 (p21), binds to regions of the human p21 promoter that contain variations of the consensus sequence in multiple copies. p150Sal2 is also shown to bind to the BAX promoter with similar elements and to activate its expression following an apoptotic stimulus. These results demonstrate binding of p150Sal2 to two natural promoters with GC elements related to the optimal binding sequence defined in vitro and whose regulation is important for suppression of tumor growth. [Copyright &y& Elsevier]

Abstract: Plasma is generated by ionizing neutral gas molecules, resulting in a mixture of energy particles, including electrons and ions. Recent progress in the understanding of non-thermal atmospheric plasma has led to applications in biomedicine. However, the exact molecular mechanisms involved in plasma-induced cell growth arrest are unclear. In this study, we investigated the feasibility of non-thermal atmospheric plasma treatment for cancer therapy and examined the mechanism by which plasma induces anti-proliferative properties and cell death in human colorectal cancer cells. Non-thermal atmospheric plasma induced cell growth arrest and induced apoptosis. In addition, plasma reduced cell migration and invasion activities. As a result, we found that plasma treatment to the cells increases β-catenin phosphorylation, suggesting that β-catenin degradation plays a role at least in part in plasma-induced anti-proliferative activity. Therefore, non-thermal atmospheric plasma constitutes a new biologic tool with the potential for therapeutic applications that modulate cell signaling and function. [ABSTRACT FROM AUTHOR]

Abstract: Human Apolipoprotein D (apoD) is upregulated under several stress conditions and pathological situations such as neurodegenerative diseases and cancers. We previously showed that apoD mRNA expression is induced in growth-arrested cells and demonstrated the specific binding of nuclear proteins to the region −514 to −475 of the promoter. Such region contains a pair of Serum Responsive Elements (SRE), an Ets-Binding Site (EBS) and a Glucocorticoid Responsive Element (GRE). In this study, we show that Parp-1, HnRNP-U, CBF-A, BUB-3, Kif4, APEX-1 and Ifi204 bind these regulatory elements of the apoD promoter. Specific binding of HnRNP-U and Parp-1 was confirmed by Electrophoretic Mobility Shift Assay (EMSA). In a biotin pull-down assay, Kif4 and BUB-3 bind preferentially the SRE1 and the EBS-GRE sites, respectively, while APEX-1 seems recruited indirectly to these elements. We found that the mRNA expression of some of these binding factors is upregulated in growth-arrested cells and that these proteins also transactivate the apoD promoter. In agreement with these results, mutants of APEX-1 and of Parp-1 defective for their DNA-binding and catalytic activities could not transactivate the promoter. The knockdown of Parp-1 and HnRNP-U and the use of specific inhibitors of MEK1/2 and of Parp-1 also inhibited the induction of apoD gene expression. Moreover, ERK1/2 was found activated in a biphasic manner post serum-starvation and the inhibition of Parp-1 causes a sustained activation of ERK2 but not ERK1 for up to 2h. Altogether, these findings demonstrate the importance of Parp-1, APEX-1 and ERK1/2 catalytic activities in the growth arrest-induced apoD gene expression. [Copyright &y& Elsevier]

Abstract: Hypochlorous acid, a chlorinating and oxidative agent, has been reported to be implicated in many pathologies. Its markers were found under inflammatory conditions and, at least some of it reveals biological activity. Thus, in this paper we examined whether N-chloroamino acids may act as mediators of the action of hypochlorous acid in cell culture. N-Chloroamino acids were found to possess lower oxidative capacity than HOCl/OCl− just after addition to the growth medium. However, all the chlorocompounds studied were cytotoxic to A549 cells, induced a dose-dependent increase in the G0/G1 fraction with simultaneous reduction in the G2/M fraction, collapse of the mitochondrial potential and caspase-dependent apoptosis. The content of cellular thiols decreased after 1-h incubation with the chlorocompounds studied. Although amino acids act as scavengers of hypochlorite in plasma, the chlorinated products formed stay reactive and the pattern of their action on cells in vitro is similar to that of hypochlorite. [Copyright &y& Elsevier]

Abstract: The Interferon-inducible gene, IFI16 has been implicated in the control of cell growth, apoptosis, angiogenesis and immunomodulation. In a previous study we demonstrated that restoring levels of IFI16 in a head and neck squamous cell carcinoma (HNSCC)-derived cell line, HNO136, reduced its growth in vitro accompanied by a marked increase in doxorubicin-induced apoptosis. To evaluate the ability of IFI16 to inhibit in vivo tumorigenesis of HNO136 cells and to characterize the molecular mechanisms responsible for its anti-tumor activity, IFI16 expression on cell growth was evaluated by an in vivo tumorigenicity assay. After excision, tumors were subjected to morphometric and immunohistochemical analyses with markers of apoptosis, angiogenesis, and inflammation. Restoring IFI16 expression significantly reduced the in vivo tumorigenesis of HNO136, decreased tumor vascularization and increased areas of tumor necrosis. Further analysis revealed that IFI16 expression triggered apoptosis of tumor cells, as evaluated using TUNEL assay. Finally, restoring IFI16 protein to HNO136 cells increased CD45+ inflammatory cell infiltration of the tumor burden, predominantly consisting of CD68/CD14 positive macrophages. In accordance with our previous in vitro experiments, this study demonstrates for the first time that IFI16 exerts in vivo anti-tumoral activity by promoting apoptosis of tumor cells, by inhibiting neo-vascularisation, and by increasing the recruitment of macrophages through the release of chemotactic factors. [Copyright &y& Elsevier]

Abstract: Correlations exist between the abundance of S100 proteins and disease pathologies. Indeed, this is evidenced by the heterodimeric S100 protein complex S100A8/A9 which has been shown to be involved in inflammatory and neoplastic disorders. However, S100A8/A9 appears as a Janus-faced molecule in this context. On the one hand, it is a powerful apoptotic agent produced by immune cells, making it a very fascinating tool in the battle against cancer. It spears the risk to induce auto-immune response and may serve as a lead compound for cancer-selective therapeutics. In contrast, S100A8/A9 expression in cancer cells has also been associated with tumor development, cancer invasion or metastasis. Clearly, there is a dichotomy and future investigations into the role of S100A8/A9 in cancer biology need to consider both sides of the same coin. [Copyright &y& Elsevier]

Abstract: Human colorectal adenocarcinoma C85 cells, treated with high dose methotrexate (1μM; IC50 =51nM), undergo accelerated senescence, as the cells (i) are growth arrested at the G1 and S phases of the cell cycle, (ii) are SA-β-galactosidase-positive, (iii) show induced expression of p21waf1/cip1 and decreased expression of p16INK4a, and (iv) show DNA synthesis continued at the reduced level. The fraction of C85 cells with DNA content higher than 4N is maintained at the same level (14%) in cells untreated, as well as regrown after the treatment. Multinucleation is found as the main karyotypic abnormality. [Copyright &y& Elsevier]

We have reported the changes in gene expression in human HeLa cells exposed to a low concentration (5μM) of Cd. In the present study, cells exposed to a higher concentration of Cd were analyzed using a DNA microarray with 9182 human cDNA probes, in an attempt to obtain a comprehensive view on the biological effects of Cd. After a 6h exposure to 50μM Cd, 48 genes were up-regulated 2.5-fold or greater and 14 genes were down-regulated to 40% or less. Marked up-regulation of genes coding for metallothioneins, anti-oxidant proteins, and heat shock proteins was observed. Cd appeared to repress cell proliferation by modulating genes involved in multiple pathways. Cd also affected a number of genes related to apoptosis. Interestingly, it appeared that a series of genes were regulated to accelerate the intrinsic pathway of apoptosis, while others were directed to suppress the extrinsic pathway. Of these, rapid and transient induction of the TR3 gene was noted as a possible key process in Cd-induced apoptosis. Effects on several genes that may reflect mechanistic backgrounds of Cd toxicity were also observed. The present study disclosed a complex pleiotypic response of human cells to Cd, which was composed of a variety of changes in gene expression directed to defense, growth arrest, recovery from damage, apoptosis and so on. [Copyright &y& Elsevier]

Abstract: The tumor suppressor p53 controls a broad range of cellular responses. Induction of a transient (cell cycle arrest) or a permanent (senescence) block of cell proliferation, or the activation of cell death pathways in response to genotoxic stress comprise the major arms of the survival-death axis governed by p53. Due to these biological properties, inactivation of p53 is a crucial step in tumor development and progression, reflected by the high incidence of TP53 mutations in different types of human cancers. The remarkable potency of p53 in suppressing tumorigenic outgrowth has promoted the expectation that tumor cells expressing wild-type p53 (wtp53) should be more prone to elimination by cytotoxic treatments than tumor cells expressing mutant p53 (mutp53) with defunct wtp53 activities. However, recent findings yielded somewhat unexpected insights concerning the preponderance of the survival-promoting effects of wtp53 in cancer cells, a rather undesired property from the therapeutic point of view. In this commentary we will discuss the possibility that the developmentally established distinct patterns of wtp53 mediated responses in different tissues are an important factor in determining the ultimate outcome of cellular responses mediated by wtp53 in different types of tumor cells, with a particular focus on the divergent impact of wtp53 in malignant tumors of the central nervous system. We infer that a selective gain of pro-survival functions of wtp53 in cancer cells will confer a survival advantage that counteracts tumor therapy. [Copyright &y& Elsevier]

Abstract: Much work has been done in the 20 years since the discovery of the first metastasis suppressor gene to investigate the diverse biochemical functions of the proteins these genes encode. The function of metastasis suppressors cannot be solely predicted from correlative clinical data or in vitro studies. Instead, careful design of in vivo experiments to test broader hypotheses is necessary to pinpoint the mechanism of action of these novel proteins. Our laboratory identified c-Jun NH2-terminal kinase activating kinase 1 (JNKK1)/Mitogen-activated protein kinase (MAPK) kinase 4 (JNKK1/MKK4) as a metastasis suppressor in prostate and ovarian cancer. JNKK1/MKK4 is a stress activated protein kinase (SAPK) involved in a variety of signaling events, ranging from the regulation of hepatoblast survival during mammalian development to metastasis suppression in adult ovarian and prostate cancers. JNKK1/MKK4 function has typically been associated with the c-Jun NH2-terminal kinase (JNK) signaling pathway, particularly in the immune system where JNK plays a role in inflammatory signaling and apoptosis. However, evidence continues to accumulate that JNKK1/MKK4 is also a physiologic activator of p38 under certain conditions, and that activation of p38 arrests cell cycle progression. This review will provide a historical perspective on the role of JNKK1/MKK4 in SAPK signaling, including some recent findings from our own laboratory that shed light on the complicated role for JNKK1/MKK4 in metastatic colonization. [Copyright &y& Elsevier]

Abstract: Ceramidases catalyze hydrolysis of ceramides to generate sphingosine (SPH), which is phosphorylated to form sphingosine-1-phosphate (S1P). Ceramide, SPH, and S1P are bioactive lipids that mediate cell proliferation, differentiation, apoptosis, adhesion, and migration. Presently, 5 human ceramidases encoded by 5 distinct genes have been cloned: acid ceramidase (AC), neutral ceramidase (NC), alkaline ceramidase 1 (ACER1), alkaline ceramidase 2 (ACER2), and alkaline ceramidase 3 (ACER3). Each human ceramidase has a mouse counterpart. AC, NC, and ACER1–3 have maximal activities in acidic, neutral, and alkaline environments, respectively. ACER1–3 have similar protein sequences but no homology to AC and NC. AC and NC also have distinct protein sequences. The human AC (hAC) was implicated in Farber disease, and hAC may be important for cell survival. The mouse AC (mAC) is needed for early embryo survival. NC is protective against inflammatory cytokines, and the mouse NC (mNC) is required for the catabolism of ceramides in the digestive tract. ACER1 is critical in mediating cell differentiation by controlling the generation of SPH and S1P and that ACER2''s role in cell proliferation and survival depends on its expression or the cell type in which it is found. Here, we discuss the role of each ceramidase in regulating cellular responses mediated by ceramides, SPH, and S1P. [Copyright &y& Elsevier]

Abstract: Cell homeostasis is regulated by proliferation, growth arrest and apoptosis. Negative growth rate controls such as growth arrest and apoptosis are vital pathways governing aberrant development in the contribution to malignancy. Apoptosis provides the mechanism by which damaged or superfluous cells are effectively removed from the cell pool. As the cell progresses from one phase to another it is tightly regulated by a number of controls. Defects of these surveillance checkpoints may lead to an accumulation of DNA abnormalities and subsequent pathological disorders. This review considers an overview of the intricate and complex regulation of the cell cycle with potential therapeutic targets. The roles of key players are highlighted in an attempt to provide an insight into the ever increasing body of evidence of interplay and pathways of cell progression, arrest and death with deregulation leading to initiation of tumourigenesis. [Copyright &y& Elsevier]

Abstract: The cyclin-dependent kinase inhibitor p21WAF1/Cip1 plays a central role in a spatial and temporal balance of epidermal keratinocyte proliferation and growth arrest. However, what controls p21 expression in keratinocytes remains uncertain. Hypoxia-inducible factor 1α (HIF-1α) does not only express a variety of genes essential for hypoxic adaptation, but also up-regulates p21 so as to slow down cell cycle under hypoxic conditions. In the present study, we examined the role of HIF-1α in p21-mediated growth arrest of keratinocyte. Keratinocyte proliferation was arrested in the G1 phase at a high cell density. p21 was also up-regulated in a cell density-dependent manner and was found to be highly expressed in epidermal keratinocytes of normal human skins. In addition, in the same specimens and cells, we noted robust HIF-1α expression. HIF-1α siRNAs inhibited p21 expression and released the G1 arrest. In vivo, moreover, the intradermal injection of HIF-1α siRNA attenuated p21 expression in rat epidermis and induced skin hyperplasia. Mechanistically, we propose that the production of mitochondrial reactive oxygen species and the activation of the MEK/ERK pathway are involved in the HIF-1α stabilization in keratinocytes. These results imply that HIF-1α functions as an up-stream player in the p21-mediated growth arrest of keratinocytes. [Copyright &y& Elsevier]

Abstract: Oncostatin M (OSM), an IL-6 family cytokine, either inhibits or enhances the growth of cells depending on cell type. Here, we report that OSM inhibits proliferation of skeletal muscle cells by blocking cell cycle progression from G1 to S phase. OSM treatment significantly reduced levels of cyclin D1 protein and phosphorylation of retinoblastoma protein (Rb) at Ser-795, a CDK4-specific phosphorylation site. The OSM-induced cyclin D1 reduction correlated with decreased amount of the cyclin D1/p27Kip1 complex and increased amounts of the CDK2/p27Kip1 complex, resulting in inhibition of CDK2 activity. Results obtained with lactacystin, a proteasome inhibitor, demonstrated that cyclin D1 reduction occurred through ubiquitin/proteasome proteolysis. In addition, activation of STAT3, but not STAT1, is likely to regulate OSM-induced cyclin D1 reduction. Dominant negative (DN)-STAT3 blocked OSM-induced cyclin D1 reduction, and constitutively active-STAT3 also induced cyclin D1 reduction. These results suggest that OSM arrests skeletal muscle cell growth at the G1/S checkpoint and that this response occurs by an ubiquitin/proteasome-dependent cyclin D1 protein reduction which is regulated by STAT3. [Copyright &y& Elsevier]

Abstract: Apolipoprotein D is a lipocalin, primarily associated with high density lipoproteins in human plasma. Its expression is induced in several pathological and stressful conditions including growth arrest suggesting that it could act as a nonspecific stress protein. A survey of cellular stresses shows those causing an extended growth arrest, as hydrogen peroxide and UV light increase apoD expression. Alternatively, lipopolysaccharide (LPS), a pro-inflammatory agonist showed a time- and dose-dependent effect on apoD expression that correlates with an increase in proliferation. At the promoter level, NF-kB, AP-1 and APRE-3 proved to be the elements implicated in the LPS response. Colocalization of apoDh–GFP fusion constructs with DNA and Golgi markers, immunocytochemistry of the endogenous protein and cell fractionation showed that both serum starvation and LPS treatment caused a displacement of apoD localization. In normal conditions, apoD is mainly perinuclear but it accumulates in cytoplasm and nucleus under these stress conditions. Since nuclear apoD appears derived from the secreted protein, it may act as an extracellular ligand transporter as well as a transcriptional regulator depending on its location. This role of apoD inside the cell is not only dependent of endogenous apoD but may also be provided by exogenous apoD entering the cell. [Copyright &y& Elsevier]

Abstract: It is NO that mediates the inhibitory effect of IFN-γ, MIP-1α and TNFα on hematopoiesis. However, the mechanism for NO effect on the hematopoietic system is likely to not clear. In the current work, we demonstrates that NO can directly suppress the colony formation of granulocyte/macrophage in vitro. Using a granulocyte/macrophage progenitor (GMP) model, HL-60 cell line, we show that NO inhibits the proliferation of HL-60 cells by inducing G0/G1 arrest and apoptosis in a dose- and time-dependent manner. Exposure of HL-60 cells to 1mM SNP for 2–48h results in marked decrease in Akt activation and Bad phosphorylation. Constitutively active Akt overexpression reduces NO-induced apoptosis and cell cycle arrest in HL-60 cells. A further investigation on apoptosis related protein shows that NO induces Bid cleavage and Bax expression but down-regulates the expression of Bcl-2 and Bcl-xL. We also demonstrate here that G0/G1 arrest is resulted from NO-induced disruption of cell cycle balance, which is mediated by up-regulation of p21waf/cip1, p27kip1 and down-regulation of cyclin D1, cyclin E. In brief, NO-induced apoptosis and G0/G1 arrest is mediated through regulation of apoptosis and cell cycle related protein, which may depend on Akt deactivation by NO, ultimately led to its inhibitory effect on hematopoiesis. [Copyright &y& Elsevier]

Abstract: It has been reported that RNAi-dependent chromatin silencing in vertebrates is not restricted to the centromeres. To address whether RNAi machinery could regulate the chromatin structure of imprinted genes, we knocked down Dicer in HEK293 cells and found that the expression of PHLDA2, one of the several genes in the imprinted gene domain of 11p15.5, was specifically upregulated. This was accompanied by a shift towards more activated chromatin at PHLDA2 locus as indicated by change in H3K9 acetylation, however, the methylation state at this locus was not affected. Furthermore, we found that PHLDA2 was downregulated in growth-arrested HEK293 cells induced by either serum deprivation or contact inhibition. This suggests that PHLDA2 upregulation might be a direct result of Dicer depletion rather than the consequence of growth arrest induced by Dicer knockdown. Considering the reports that there is consistent placental outgrowth in PHLDA2 knockout mice and that PHLDA2 overexpression in mice causes growth inhibition, we speculate that PHLDA2 may be a candidate for contributing to the reduced growth rate of Dicer-deficient cells and the very early embryonic lethality in Dicer knockout mice. [Copyright &y& Elsevier]

Abstract: Functional studies of the canonical Bone Morphogenetic Protein (BMP) signalling pathway in human epidermal keratinocytes have been limited to the immortalized and p53-mutated HaCaT cells and are primarily dependent on BMP6 treatment in mouse epidermal keratinocytes. Despite these insightful analyses, the molecular mechanism underlying the role of BMP signalling in the precise balance between growth arrest and terminal differentiation of keratinocytes still remains not clearly defined. The current study first investigated the hitherto uncharacterized status and functions of BMP signalling in normal human keratinocytes by using three independent strains of primary interfollicular epidermal keratinocytes. Then we provided data demonstrating the role of BMP2 compared to BMP6 in the inhibition of growth and induction of subsequent terminal differentiation of these cells. A second relevant finding is based on the clonal analysis of colony types present in untreated and BMP2/6-treated cultures in absence of EGF. BMP treatment results in the clonal transition from proliferative to abortive colonies, suggesting that BMP signalling most likely inhibits stem cell proliferation and triggers cell cycle exit from transit amplifying cells. Third, we showed evidence that, of the three members of the Cip/Kip family of cyclin-dependent kinase inhibitors, only p57Kip2 and p21Cip1 have a BMP2/6-induced expression. One mechanism of inhibition of cell proliferation involves p57Kip2 as an immediate early response, in contradistinction with p21Cip1 which largely depends on de novo protein synthesis for its effect to proceed. All together, these results clarify the BMP signalling status in normal primary human keratinocytes and support a new mechanism of inhibition of the proliferation of interfollicular epidermal keratinocytes coupled with induction of their terminal differentiation following BMP2 or BMP6 addition. [Copyright &y& Elsevier]

Abstract: Mortalin was first cloned as a mortality factor that existed in the cytoplasmic fractions of normal, but not in immortal, mouse fibroblasts. A decade of efforts have expanded its persona from a house keeper protein involved in mitochondrial import, energy generation and chaperoning of misfolded proteins, to a guardian of stress that has multiple binding partners and to a killer protein that contributes to carcinogenesis on one hand and to old age disorders on the other. Being proved to be an attractive target for cancer therapy, it also warrants attention from the perspectives of management of old age diseases and healthy aging. [Copyright &y& Elsevier]

Abstract: Novel chemotherapeutic agents derived from active phytochemicals could be used as adjuvants and improve the anti-carcinogenicity of standard drug treatments. However, their precise mechanisms of action are sometimes unclear. In this study, the anti-carcinogenic effect of the herbal diterpenoid pseudolaric acid B (PAB) on the growth and apoptosis of colon cancer cells was investigated, and to compare that with the more toxic compound triptolide. PAB induced growth inhibition and apoptosis in HT-29 cells, which were associated with cell cycle arrest at the G2/M phase, modulation of cyclin expression and downregulation of the protooncogene c-myc. In addition, PAB also inhibited bcl-xL expression, induced cleavage of procaspase-3 and its substrate poly(ADP-ribose) polymerase (PARP), which together caused DNA fragmentation and nuclear chromatin condensation. Concomitantly, the modulation of the growth-related and apoptotic factors by PAB was accompanied by the increased protein and gene expression of the nonsteroidal anti-inflammatory drug-activated gene (NAG-1), which occurred along with cyclooxygenase-2 inhibition. The effects of PAB on PARP cleavage and NAG-1 overexpression were not reversible upon removal of the drug from the culture medium. Similar cytotoxic and pro-apoptotic effects were also attained by treating the HT-29 cells with another diterpenoid triptolide, but its actions on cell cycle progression and on the upstream transcriptional regulation of NAG-1 both took place in a less coherent manner. These findings exemplify the potential of herbal terpenoids, particularly PAB, in modulating colon cancer carcinogenesis through known molecular targets and precise mechanism of action. [Copyright &y& Elsevier]

Abstract: Human chronic myelogenous leukemia (CML) cell line K562 can be chemically induced to differentiate and express embryonic and fetal globin genes. In this study, the effects of doxorubicin (DOX), an inducer of K562 cell erythroid differentiation, with those of epidoxorubicin (EDOX) as well as newly synthesized derivatives of both drugs (DOXM, DOXH, and EDOXM) on cell growth and differentiation were compared. Our results revealed that DOX, EDOX and their derivatives caused irreversible differentiation of K562 cells into more mature hemoglobin-containing cells. This phenomenon was linked to time-dependent inhibition of cell proliferation. Considering the impact of the structure of newly synthesized anthracyclines on their cellular activity, our data clearly indicated that among tested anthracyclines DOXM, a morpholine derivative of DOX exerted the highest antiproliferative and differentiating activity. An increase of γ-globin mRNA level caused both by high transcription rate and by mRNA stabilization, as well as an enhancement of expression but not activity of erythroid transcription factor GATA-1 were observed. Therefore, a high level of hemoglobin-containing cells in the presence of DOXM resulted from transcriptional and post-transcriptional events on γ-globin gene regulation. The same morpholine modification introduced to EDOX did not cause, however, similar effects on cellular level. Characterization of new powerful inducers of erythroid differentiation may contribute to the development of novel compounds for pharmacological approach by differentiation therapy to leukemia or to β-globin disorder, β-thalassemia. [Copyright &y& Elsevier]

Abstract: Sulindac, a nonsteroidal anti-inflammatory drug (NSAID), induces growth arrest in HeLa cells and causes strong inhibition of the G1 to S transition of the cell cycle in a concentration-dependent manner. The G1 arrest is preceded by suppression of cyclin E and A, inactivation of cdk2, and the complete loss of the viral oncoprotein E7, despite ongoing HPV transcription. As shown by inhibitors specific for cyclooxygenase (COX) 1 and 2 loss of E7 is COX-independent. Moreover, inhibition of the proteasome activity with MG132 partially blocked the ability of sulindac to suppress E7 suggesting that sulindac induces degradation of E7 by the proteasomal pathway. In addition to inhibiting growth, sulindac strongly induces apoptosis, which can be abrogated by using the general caspase inhibitor zVAD-fmk. Unchanged expression of the pro-apoptotic protein Bax and suppression of the anti-apoptotic molecules Bcl-2 and Bcl-xL argues for the engagement of the mitochondrial apoptotic pathway. These results support the notion that sulindac is a potent growth inhibitor and inducer of apoptosis on cervical cancer cells in vitro and may offer new perspectives as a chemopreventive or supplementary anti-cervical cancer drug. [Copyright &y& Elsevier]

Abstract: Over many centuries, herbal remedies have treated a variety of ailments. This empiric observational approach has produced a number of leads for formulated medicines. Ganoderma lucidum extract was screened for its anti-proliferative activity using a panel of 26 human cancer cell lines. The six most sensitive hematologic cell lines were: HL-60 (ED50 26μg/ml), U937 (63μg/ml), K562 (50μg/ml), Blin-1 (38μg/ml), Nalm-6 (30μg/ml) and RPMI8226 (40μg/ml). Cell cycle analyses revealed a G2/M arrest, most prominently in HL-60 cells. Four hematopoietic cell lines (HL-60, Blin-1, U937, RPMI8226) were examined for apoptosis, which ranged between 21 and 92%. After exposure to G. lucidum extract, HL-60 cells became multinucleated with an increased DNA content. These results indicate that G. lucidum extract has a profound activity against leukemia, lymphoma and multiple myeloma cells and may be a novel adjunctive therapy for the treatment of hematologic malignancies. [Copyright &y& Elsevier]

Abstract: New derivatives of daunorubicin (DRB), doxorubicin (DOX), and epidoxorubicin (EDOX) with an amidine group bonded to C-3′ of daunosamine moiety with either morpholine or hexamethyleneimine ring attached to the amidine group are studied in this paper. We have shown that all of these newly synthesized anthracycline derivatives inhibit human leukemia K562 cell line proliferation but only some of them induce erythroid differentiation when used at subtoxic concentrations. Morpholine derivative of DOX has the greatest potential to inhibit proliferation and to induce differentiation in vitro. The correlation between these two cellular processes was also significant for other tested compounds. In cell cycle analysis, we have demonstrated that those anthracycline derivatives that exert the greatest cytostatic potential caused G2/M arrest, which in turn, might contribute to the development of a differentiating phenotype. The concentrations of the compounds used in the study are pharmacologically relevant. These new potent inducers of differentiation might be exploited as anticancer drugs for treatment of leukemia by differentiation therapy. [Copyright &y& Elsevier]

Abstract: Growth inhibitory activity of interferons (IFNs) has been attributed to several events. These include rapid induction of cyclin-dependent kinase inhibitors, such as those in the Cip/Kip and Ink4 families and down-regulation of c-myc mRNA and c-Myc transcriptional activity. Here, we report an additional mechanism, involving regulation of Myc protein levels, through which type 1 IFN may halt proliferation of cells. This was discovered using a cell line which constitutively expresses c-myc from a retrovirus vector and which was reported to have undergone deletion of genes encoding the Ink4 tumor suppressors p15 and p16. IFNβ caused a reduction in the steady state level of c-Myc protein by increasing degradation through the 26S proteasome. Our data, as well as that of others, indicate that multiple levels of c-Myc expression can be affected by IFN treatment and this contributes to rapid growth arrest in the G1 phase of the cell cycle. [Copyright &y& Elsevier]

Abstract: A novel β-carboline alkaloid, tangutorine (benz[f]indolo[2,3-a]quinolizidine) was isolated from the leaves of Nitraria tangutorum L. [Duan JA, Williams ID, Che CT, Zhou RH, Zhao RH, Tangutorine: a novel β-carboline alkaloid from Nitraria tangutorum. Tetrahedron Lett 1999;40:2593–6], and its unique structural characters led us to initiate a study of its potential anti-proliferation activity. The in vitro treatment with low doses of tangutorine slightly stimulated the proliferation of human colon cancer HT29 cells until at concentrations higher than 6.25μg/ml when the cell numbers, cellular MTT reduction, and cell proliferation by 3H-thymidine incorporation decreased in a dose-dependent manner (IC50 =15μg/ml=48μM). Morphological studies of cells by fluorescence and electron microscopy did not show features for apoptosis but only large vacuoles, swollen mitochondria and dense cytoskeletal filaments bunching in the cytoplasm. Immunoblotting analysis revealed a dramatic induction of cyclin kinase inhibitor p21 as well as an inhibition of topoisomerase II expression at 25μg/ml tangutorine, thereby impeding cell progression from S to G2/M phase. Cells accumulated at G1 phase of the cell cycle at concentrations ≥50μg/ml tangutorine. Interestingly, some cells escaped from prolonged growth arrest without cell division and resulted in binucleated and polyploid G1 cells. Taken all results together, tangutorine induced a p21 suppression of all cyclins and their associated kinases, such as the topoisomerase II, and thus inhibited normal DNA replication and mitosis. [Copyright &y& Elsevier]

Absract: The molecular effects of Saussurea lappa extracts, a traditional medicine in Eastern Asia, on the fate of gastric carcinoma have not been understood. In this study, its cytostatic effects were examined using gastric AGS cancer cells. Its treatment resulted in apoptosis and G2-arrest in a dose- and time-dependent manner. The effects were attributed to the regulation of cyclins and pro-apoptotic molecules and suppression of anti-apoptotic molecules. Therefore, these results suggest that extracts of S. lappa root may be a candidate to deal with gastric cancers either by traditional herbal therapy or by combinational therapy with conventional chemotherapy. [Copyright &y& Elsevier]

Abstract: There are two isoforms of the prototypical human uracil-DNA glycosylase: one mitochondrial (UDG1) and one nuclear (UDG1A). Results presented here reveal a novel genetic organization of UDG1. Specifically, the UDG1 5′ UTR is composed of two non-coding exons and the promoter region is located much farther upstream than previously recognized. We also examine the proliferation-dependent expression of UDG1A and demonstrate that the protein disappears rapidly as cells transit from the cell cycle into G0. Ribonuclease protection assays reveal that UDG1A mRNA levels are greatly reduced during G0 as well. To begin to characterize the mechanisms contributing to this regulation, we identified two overlapping candidate E2F binding sites (denoted A and B) in the UDG1A 5′ UTR. EMSA analysis of this region shows a unique protein complex present only in extracts derived from G0 cells. In vitro studies using purified E2F-4 and mutant competitors demonstrate that binding occurs in a proliferation-dependent manner exclusively to E2F site A. Two approaches were then used to assess the in vivo role of the candidate E2F sites. First, chromatin immunoprecipitation (ChIP) analysis demonstrates that E2F-4 binds to the UDG1A 5′ UTR exclusively in G0 cells. Secondly, using transient transfection analysis, we show that mutating these sites abolishes the proliferation-dependent response of UDG1A. [Copyright &y& Elsevier]