No abstract

Emerging evidence indicates that reprogramming of energy metabolism involving disturbances in energy production from a defect in cellular respiration with a shift to glycolysis is a core hallmark of cancer. Alterations in cancer cell energy metabolism are linked to abnormalities in mitochondrial function. Mitochondrial dysfunction of cancer cells includes increased glycolysis, decreased apoptosis, and resistance to radiotherapy. The study was designed for two main points: firstly, to investigate whether exogenous functional mitochondria can transfer into glioma cells and explore the underlying molecular mechanisms from the perspective of endocytosis; secondly, to further verify whether the mitochondrial transplantation is able to rescue aerobic respiration, attenuate the Warburg effect and enhance the radiosensitivity of gliomas. Methods: Mitochondria were isolated from normal human astrocytes (HA) and immediately co-incubated with starved human glioma cells (U87). Confocal microscopy and gene sequencing were performed to evaluate the ability of isolated mitochondria internalization into U87 cells. The interaction between endocytosis and isolated mitochondria transfer were captured by 3D tomographic microscopy and transmission electron microscopy. NAD + , CD38, cADPR and Ca 2+ release were determined by commercial kits, western blot, HLPC-MS and Fluo-3 AM respectively. PCR array expression profiling and Seahorse XF analysis were used to evaluate the effect of mitochondrial transplantation on energy phenotypes of U87 cells. U87 cells and U87 xenografts were both treated with mitochondrial transplantation, radiation, or a combination of mitochondrial transplantation and radiation. Apoptosis in vitro and in vivo were detected by cytochrome C, cleaved caspase 9 and TUNEL staining. Results: We found that mitochondria from HA could be transferred into starved U87 cells by simple co-incubation. Starvation treatment slowed the rate of glycolysis and decreased the transformation of NAD + to NADH in U87 cells. A large amount of accumulated NAD + was released into the extracellular space. CD38 is a member of the NAD + glycohydrolase family that catalyzes the cyclization of extracellular NAD + to intracellular cADPR. cADPR triggered release of Ca 2+ to promote cytoskeleton remodeling and plasma membrane invagination. Thus, endocytosis involving isolated mitochondria internalization was mediated by NAD + -CD38-cADPR-Ca 2+ signaling. Mitochondrial transfer enhanced gene and protein expression related to the tricarboxylic acid (TCA) cycle, increased aerobic respiration, attenuated glycolysis, reactivated the mitochondrial apoptotic pathway, inhibited malignant proliferation of U87 cells. Isolated mitochondria injected into U87...

Abnormal immunity and its related complications are the major causes of mortality and morbidity in diabetes patients. Macrophages, as one of the important innate cells, play pivotal roles in controlling immune homeostasis, immunity, and tolerance. The effects of hyperglycemia on the function of macrophages in hosts remain to be determined. Here we used mice with streptozotocin (STZ)-induced diabetes for long term to study the changes of macrophages. We found that F4/80(+) peritoneal exudate macrophages (PEMs) from mice with diabetes for 4 months displayed significantly reduced CD86 and CD54 expression and tumor necrosis factor (TNF)-α and IL-6 production but enhanced nitric oxide (NO) secretion compared with control mice when treated with interferon (IFN)-γ and lipopolysaccharide (LPS), while the activity of arginase in PEMs from diabetic mice was significantly higher than control mice when stimulating with IL-4. These dysfunctions of macrophages could be efficiently reversed by insulin treatment. Importantly, in vitro bone marrow-derived macrophages showed similar functional changes, indicating the epigenetic alteration of macrophage precursors in these mice. In an in vitro culture system, high glucose and insulin significantly altered TNF-α, IL-6, and NO production and arginase activity of macrophages, which was reversed by the treatment with AKT and ERK inhibitors. Therefore, hyperglycemia and insulin deficiency can modify macrophage function through AKT-mTOR and ERK pathways and through epigenetic effects on macrophage precursors. To further identify different components of diabetes on the dysfunction of macrophages is important for efficient prevention of diabetic complications.

Gliotoxin is a natural mycotoxin with immunosuppressive and antimicrobial activity. Inhibition of farnesyltransferase (IC50 80 microM) and geranylgeranyltransferase I (IC50 17 microM) stimulated interest in the potential antitumor activity of this epidithiodioxopiperazine. Gliotoxin inhibited proliferation of six breast cancer cell lines in culture with mean +/- SD IC50 289 +/- 328 microM (range 38-985 microM); intracellular farnesylation of Lamin B and geranylgeranylation of Rap1A were inhibited in a dose-dependent manner. In randomized controlled studies using the N-methyl-N-nitrosourea rat mammary carcinoma model, gliotoxin had pronounced antitumor activity in vitro and little systemic toxicity when administered to 10 animals at 10 mg/kg by subcutaneous injection weekly for 4 wk compared with 10 controls. Single doses up to 25 mg/kg were well tolerated. The present studies confirm that gliotoxin is a dual inhibitor of farnesyltransferase and geranylgeranyltransferase I with pronounced antitumor activity and favorable toxicity profile against breast cancer in vitro and in vivo.

The metabolic regulation of cell death is sophisticated. A growing body of evidence suggests the existence of multiple metabolic checkpoints that dictate cell fate in response to metabolic fluctuations. However, whether microRNAs (miRNAs) are able to respond to metabolic stress, reset the threshold of cell death, and attempt to reestablish homeostasis is largely unknown. Here, we show that miR-378/378* KO mice cannot maintain normal muscle weight and have poor running performance, which is accompanied by impaired autophagy, accumulation of abnormal mitochondria, and excessive apoptosis in skeletal muscle, whereas miR-378 overexpression is able to enhance autophagy and repress apoptosis in skeletal muscle of mice. Our in vitro data show that metabolic stress-responsive miR-378 promotes autophagy and inhibits apoptosis in a cell-autonomous manner. Mechanistically, miR-378 promotes autophagy initiation through the mammalian target of rapamycin (mTOR)/unc-51-like autophagy activating kinase 1 (ULK1) pathway and sustains autophagy via Forkhead box class O (FoxO)-mediated transcriptional reinforcement by targeting phosphoinositide-dependent protein kinase 1 (PDK1). Meanwhile, miR-378 suppresses intrinsic apoptosis initiation directly through targeting an initiator caspase—Caspase 9. Thus, we propose that miR-378 is a critical component of metabolic checkpoints, which integrates metabolic information into an adaptive response to reduce the propensity of myocytes to undergo apoptosis by enhancing the autophagic process and blocking apoptotic initiation. Lastly, our data suggest that inflammation-induced down-regulation of miR-378 might contribute to the pathogenesis of muscle dystrophy.

The present study investigated the relationship between the expression of miR-146a and miR-146b with the occurrence and prognosis of papillary thyroid carcinoma. Experiments in vitro were also used to explore the effect of the knocked down expression of the miRNAs on growth and migration of papillary thyroid carcinoma cells. A total of 73 patients with papillary thyroid carcinoma admitted to Yidu Central Hospital of Weifang from September 2013 to September 2015 were enrolled in the study. Carcinoma samples were obtained from each patient, and adjacent tissues were used as control samples to determine expression levels of miR-146a and miR146b by semi-quantitative RT-PCR. An analysis was conducted to find possible correlations between the miRNAs expression levels and clinicopathological features in the patients followed up for one year after diagnosis. Additionally, to examine the function of miR-146a and miR-146b on TPC-1 cells, the expression of miRNAs was knocked down using specific siRNAs. MTT and Transwell assays were used to evaluate cell proliferation and migration, respectively, in the miRNA cell lines. Finally, western blot analysis was used to analyze the expression of IRAK1 in PTC cancer cells. Our results showed that the expression levels of miR-146a and miR-146b in carcinoma tissues were significantly higher than the levels in cancer-free tissues (P<0.01). The relative expression levels of miR-146a and miR-146b in cancerous tissues could be associated with the pathological type and presence or absence of lymph node metastasis (P<0.05). Compared with the siRNA-control cell, MTT and Transwell assays showed that the cell growth and migration of TPC-1 cells were decreased in miR-146a and miR-146b low expression cells (P<0.01). Western blot analysis showed that the expression of IRAK1 in papillary thyroid carcinoma was higher than in adjacent tissue (P<0.01). Based on our findings, the expression of miR-146a and miR-146b correlates with the occurrence and prognosis of papillary thyroid carcinoma, and the expression levels of miR-146a and miR-146b seem to affect the cell proliferation and migration and regulate the expression of IRAK1 protein in cancer cells. Further studies are needed to validate our results to provide new targets for prevention and treatment of papillary thyroid carcinoma.

No abstract

BackgroundCD133 and Nestin, as the markers of cancer stem cells, have recently been reported frequently in the pathogenesis and development of human gliomas. However, the prognostic role of CD133 and Nestin in gliomas still remains controversial. In this study, we aimed to evaluate the association between the expression of CD133 and Nestin and the outcome of glioma patients by conducting a systematic review and meta-analysis.MethodsWe performed systematically electronic and manual searches through the database of Pubmed and embase (until to December 25, 2014) for titles and abstracts which investigated the relationships between CD133 and Nestin expression and outcome of glioma patients. A systematic review and meta-analysis was executed to generate Pooled hazard ratios (HRs) with 95 % confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS).ResultsA total of 1,490 patients from 32 studies (13 articles) were included in the analysis. 19 studies and 13 studies investigated correlation between CD133 expression or Nestin and survival in gliomas, respectively. Our results showed that high CD133 expression in patients with glioma was associated with poor prognosis in terms of OS (HR 1.69; 95 % CI, 1.16–2.47; P =0.0060) and PFS (HR, 1.64; 95 % CI, 1.12–2.39; P = 0.010). In addition, high Nestin expression were associated with worse OS (HR 1.751; 95 % CI, 1.19–2.58, p = 0.004) but has no significant association with PFS (HR 1.55; 95 % CI, 0.96–2.51, p = 0.074). Even more important, the results of the subgroup meta-analyses show that that high CD133 expression was associated with worse prognosis in terms of OS and PFS in patients with WHO IV glioma but not WHO II-III. On the other hand, Nestin high expression was associated with worse prognosis in terms of OS and PFS in patients with WHO II-III glioma but not WHO IV.ConclusionHigh level of CD133 expression trends to correlate with a worse OS and PFS in glioma patients, especially WHO IV gliomas and Nestin high expression trends to correlate with a worse OS in glioma patients especially WHO II–III, revealing both the markers of cancer stem cells may as the potential pathological prognostic markers for glioma patients.