Effects of ferroptosis-related gene HSPB1 on acute myeloid leukemia.

INTRODUCTION: The purpose of this study was to investigate the effects and potential mechanisms of ferroptosis-related gene heat shock protein beta-1 (HSPB1) on acute myeloid leukemia (AML). METHODS: The RNA-seq and clinical data of AML samples were obtained from the Genomic Data Commons database, and the FerrDb database was used to screen the marker, drive and suppressor of ferroptosis. Besides, DESeq2 was applied for differential expression analysis on AML samples and screening for differentially expressed genes (DEGs). The screened DEGs were subjected to the intersection analysis with ferroptosis-related genes to identify the ferroptosis-related DEGs. Next, the functional pathways of ferroptosis-related DEGs were further be discussed by Gene Ontology as well as Kyoto Encyclopedia of Genes and Genomes enrichment analysis of DEGs. Additionally, lasso regression analysis was employed to determine the differential genes related to prognosis in patients with AML and the survival analysis was performed. Subsequently, quantitative real-time polymerase chain reaction and western blot assay were applied to detect the mRNA and protein expression levels of HSPB1 in normal/AML bone marrow tissues and human normal (HS-5)/AML (HL-60) bone marrow cells, respectively. Furthermore, HSPB1 was knocked down to assess the expression changes of glutathione peroxidase 4 and acyl-CoA synthetase long-chain family member 4. Ultimately, the viability and oxidative stress levels of HL-60 were analyzed by Cell Counting Kit-8 and biochemical detection. RESULTS: A total of 4986 DEGs were identified in AML samples, with 3324 up-regulated and 1662 down-regulated. The enrichment analysis illustrated that ferroptosis-related DEGs were significantly enriched in response to metal irons, oxidative stress, and other pathways. After lasso regression analysis, 17 feature genes related to the prognosis of patients with AML were obtained, with HSPB1 exhibiting a significant correlation. The reliability of our models was verified by Cox regression analysis and survival analysis of the hazard model. Furthermore, the outcomes of quantitative real-time polymerase chain reaction and western blot showed that mRNA and protein expression levels of HSPB1 were significantly increased in the AML Group and HL-60 cells. The knockdown of HSPB1 in HL-60 cells reduced the protein level of glutathione peroxidase 4, increased the protein level of acyl-CoA synthetase long-chain family member 4, decreased the cell viability, and aggravated oxidative stress. CONCLUSION: Ferroptosis-related gene HSPB1 is highly expressed in patients with AML. In addition, HSPB1 may be involved in the occurrence and development of AML by regulating oxidative stress and ferroptosis-related pathways. This study provides new clues for further understanding of AML molecular mechanisms. Also, HSPB1 is expected to be a potential therapeutic target for AML in the future.

An adolescent with primary cutaneous follicle center lymphoma: a case report and literature review.

Primary cutaneous follicle center lymphoma (PCFCL) differs from follicular lymphoma in biological behavior and molecular profile and is treated as a distinct entity, according to the 5th edition of the World Health Organization classification of hematolymphoid tumors. It is an uncommon cutaneous B-cell lymphoma that is considerably rare in children and adolescents. To date, only 13 cases of individuals younger than 20 years of age have been reported in the literature. The lack of relevant clinical epidemiological data in this population has hampered the investigation of its clinical and diagnostic aspects. Here we report the case of a 17-year-old male with PCFCL, who may be the first PCFCL patient under 20 years of age reported in China. He was admitted to the hospital with a solitary nodule on his face. After complete surgical excision, the patient's facial mass was histologically identified as PCFCL. The patient's prognosis was favorable, with no recurrence at 17 months of follow-up after the surgical resection. We present a case of an adolescent PCFCL patient and systematically review the literature with a view to increase the awareness of the disease and inform the diagnosis and treatment of this age group.

MCAD activation by empagliflozin promotes fatty acid oxidation and reduces lipid deposition in NASH.

Medium-chain acyl-CoA dehydrogenase (MCAD) is one of the significant enzymes involved in the ß-oxidation of mitochondrial fatty acids. MCAD deficiency affects the ß-oxidation of fatty acid and leads to lipid deposition in multiple organs, but little is known about its importance in nonalcoholic steatohepatitis (NASH). Empagliflozin is revealed to effectively improve NASH by increasing research, whereas the specific mechanism still has to be explored. Human liver tissues of patients with or without NASH were obtained for proteomic analysis to screen proteins of interest. db/db mice were given empagliflozin by gavage for 8 weeks. The expression of MCAD and signaling molecules involved in hepatic lipid metabolism was evaluated in human liver, mice and HL7702 cells. We found that the MCAD levels in the liver were significantly reduced in NASH patients compared to patients without NASH. Protein-protein interaction network analysis showed that MCAD was highly correlated with forkhead box A2 (FOXA2) and protein kinase AMP-activated catalytic subunit alpha (PRKAA). AMPK/FOXA2/MCAD signaling pathway was detected to be inhibited in the liver of NASH patients. Decreased expression of MCAD was also observed in the livers of db/db mice and hepatocyte treated with palmitic acid and glucose. Of note, empagliflozin could upregulate MCAD expression by activating AMPK/FOXA2 signaling pathway, reduce lipid deposition and improve NASH in vivo and in vitro. This research demonstrated that MCAD is a key player of hepatic lipid deposition and its targeting partially corrects NASH. MCAD thus may be a potential therapeutic target for the treatment of NASH.

A New Case of Hb Headington (HBB: c.217A>C) Due to a New DNA Transversion, Found in a Patient with Type 2 Diabetes Mellitus.

We here report a novel case of Hb Headington [ß72(E16)Ser→Arg, HBB: c.217A>C, p.Ser73Arg], in a 68-year-old woman with type 2 diabetes mellitus (T2DM). Glycosylated hemoglobin (Hb) was measured by capillary electrophoresis (CE). The spectrum showed abnormal peaks between the A0 and A2 peaks. DNA sequencing demonstrated a mutation on the HBB gene, which predicted a substitution of serine to arginine at position 73 in the ß-globin chain. Moreover, this amino acid substitution occurs at the same position as Hb Headington [ß72(E16)Ser→Arg, HBB: c.219T>A, p.Ser73Arg], which showed increased oxygen affinity.

Circulating Serum Myonectin Levels in Obesity and Type 2 Diabetes Mellitus.

OBJECTIVE: Myonectin is one of the myokines and has gained interest as a potential new strategy to combat obesity and its associated disorders, such as type 2 diabetes mellitus (T2DM).The objective of this study was to investigate circulating serum myonectin levels in nondiabetes and T2DM and elucidate possible relationships between serum myonectin levels and metabolic parameters in patients with T2DM. DESIGN: A total of 362 Chinese patients with T2DM and 100 age- and sex-matched healthy controls were recruited in this study. Clinical characteristics, blood biochemistry, and circulating myonectin levels were measured by enzyme-linked immunosorbent assay. RESULTS: Circulating myonectin levels were significantly decreased in T2DM compared with controls. Obese nondiabetic controls had significantly lower serum myonectin levels compared with lean nondiabetic controls. In diabetic patients, serum myonectin concentrations were significantly negatively correlated with body mass index (BMI), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), C-reactive protein (CRP), hemoglobin A1c (HbA1c), fasting insulin (Fins), the homeostatic model assessment of insulin resistance (HOMA-IR), visceral fat area, and subcutaneous fat area. After adjusting for covariates, multivariate stepwise regression analysis demonstrated that BMI, LDL-C, TG, HOMA-IR, and visceral fat were the main independent predictors of low serum myonectin concentrations. CONCLUSIONS: Circulating myonectin levels were decreased in T2DM patients and in obese subjects. Moreover, serum myonectin levels were correlated with metabolic markers of T2DM. These data suggest that myonectin may be a useful marker in predicting the development of obesity and T2DM.

Discovery and anti-diabetic effects of novel isoxazole based flavonoid derivatives.

3-O-[(E)-4-(4-cyanophenyl)-2-oxobut-3-en-1-yl] kaempferol is a novel lead compound to discover anti-diabetic and anti-obesity drugs. The present study reported the scaffold hopping of the lead compound to obtain a new isoxazole derivative, C45, which has improved glucose consumption at the nanomolar level (EC50 = 0.8 nM) in insulin resistant (IR) HepG2 cells. Western blotting showed that C45 markedly enhanced the phosphorylation of AMPK (AMP-activated protein kinase) and reduced the levels of the gluconeogenesis key enzymes PEPCK (phosphoenolpyruvate carboxykinase) and G6Pase (glucose 6-phosphatase) in HepG2 cells. The potential molecular mechanism of C45 may be activation of the AMPK/PEPCK/G6Pase pathways. We concluded that C45 might be a valuable candidate to discover anti-diabetic drugs.

Flavonoid derivatives synthesis and anti-diabetic activities.

In high fat diet-induced obese mice, the flavonoid derivative of tiliroside, Fla-CN, has antihyperglycemic effects, can improve insulin sensitivity, ameliorate metabolic lipid disorders, and benefits certain disorders characterized by insulin resistance. Fla-CN is a novel lead compound to discovery anti-diabetic and anti-obesity drugs. The present study reported the optimization of Fla-CN to obtain a new derivative, 10b, which has improved glucose consumption at the nanomolar level (EC50 = 0.3 nM) in insulin resistant (IR) HepG2 cells. 10b also increased the glycogen content and glucose uptake, and concurrently inhibited gluconeogenesis in HepG2 cells. Western blotting showed that 10b markedly enhanced the phosphorylation of AMPK (AMP-activated protein kinase) and AS160 (protein kinase B substrate of 160 kDa) and reduced the levels of the gluconeogenesis key enzymes PEPCK (phosphoenolpyruvate carboxykinase) and G6P (glucose 6-phosphatase) in HepG2 cells. The potential molecular mechanism of 10b may be activation of the AMPK/AS160 and AMPK/PEPCK/G6P pathways. We concluded that 10b might be a valuable candidate to discover anti-diabetic drugs.

Inhibition of microRNA-124a attenuates non-alcoholic fatty liver disease through upregulation of adipose triglyceride lipase and the effect of liraglutide intervention.

AIM: Glucagon-like peptide-1 receptor agonists (GLP-1Ras) have been reported to prevent non-alcoholic fatty liver disease (NAFLD), but the potential mechanisms are still debated. MicroRNAs (miRNAs) play a prominent role in the field of metabolic disorders, including NAFLD. Our study was designed to further evaluate the effect of GLP-1Ra liraglutide on NAFLD in terms of miRNAs. METHODS: MicroRNA expression was evaluated by clustering analysis of microRNA arrays in high fat diet-fed mice. The luciferase reporter assay was carried out to validate the cross-talk between adipose triglyceride lipase (ATGL) and miR-124a. MicroRNA-124a mimics and inhibitor plasmids were transfected to study the role of miR-124a in palmitate-treated normal human liver cell line (HL-7702). Liraglutide treatment was used to observe the effect of GLP-1Ra on the miR-124a/ATGL pathway. RESULTS: Expression of ATGL decreased and miR-124a expression increased in hepatosteatosis in vivo and in vitro. Mechanistically, miR-124a interacted with the 3'-untranslated region of ATGL mRNA and induced its degradation. MicroRNA-124a overexpression antagonized the effect of liraglutide on NAFLD by inhibiting ATGL expression, whereas miR-124a knockdown led to elevated ATGL and sirtuin 1 (Sirt1) expression, and subsequently decreased lipid accumulation and inflammation in cells. CONCLUSIONS: MicroRNA-124a overexpression contributes to the progression of NAFLD through reduction of ATGL expression, whereas miR-124a knockdown can reverse this trend, suggesting that miR-124a and its downstream target ATGL can be novel therapeutic targets of NAFLD. We reveal a novel mechanism by which liraglutide attenuates NAFLD by the miR-124a/ATGL/Sirt1 pathway.

The relationship between circulating irisin levels and tissues AGE accumulation in type 2 diabetes patients.

Advanced glycation end-products (AGEs), measured by skin autofluorescence (AF), are a factor in the development or worsening of many degenerative diseases, such as diabetes and atherosclerosis. Irisin levels have been associated with diabetes, endothelial dysfunction and atherosclerosis. The objective of the present study was to investigate whether circulating irisin levels are correlated with skin AF values in type 2 diabetes patients. A total of 362 Chinese type 2 diabetic patients and 100 age- and sex-matched healthy controls were recruited in the present study. Clinical characteristics, blood biochemistry and circulating irisin levels were measured. Skin AF was measured using an AGE reader. Circulating irisin levels were significantly lower, while skin AF values were increased in type 2 diabetes compared with controls (P<0.05 respectively). By dividing the distribution of skin AF values into tertiles, serum irisin levels gradually lowered with increasing skin AF values (P<0.05). After adjusting for covariates, multivariate stepwise regression analysis demonstrated that serum lower irisin levels were independently associated with skin AF (P=0.009). Circulating irisin levels were lower in type 2 diabetes patients compared with healthy controls. Lower levels of irisin are independently associated with elevated skin AF values, indicating that circulating irisin levels could be associated with AGEs accumulation, which is one of the reasons causing vascular complications in diabetic patients.

miR-203 inhibits cell growth and regulates G1/S transition by targeting Bmi-1 in myeloma cells.

The oncogene B-cell-specific Moloney murine leukemia virus insertion site­1 (Bmi­1) is overexpressed in multiple myeloma (MM). Our previous study demonstrated that Bmi­1 silencing sensitized MM cells to bortezomib. Translational regulation has emerged as a prominent underlying mechanism of Bmi­1 regulation, particularly via microRNA targeting. The present study determined that Bmi­1 may be directly targeted by miR­203 using a luciferase assay. In addition, enforced expression of miR-203 led to significant downregulation of Bmi­1 protein and mRNA expression levels. Furthermore, restoration of miR-203 significantly inhibited cell growth and G1/S transition in MM cells. miR­203 was downregulated in MM patients, and a negative correlation between the expression of miR­203 and Bmi­1 was observed. The results of the present study indicated that miR­203 exerts growth­inhibiting effects in MM through the suppression of Bmi­1 expression. In conclusion, the present study demonstrated that Bmi­1 is a direct functional target of miR-203 in MM.

miR-299-5p promotes cell growth and regulates G1/S transition by targeting p21Cip1/Waf1 in acute promyelocytic leukemia.

MicroRNAs (miRs) are often located in genomic breakpoint regions and are hypothesized to be important regulators involved in the regulation of critical cell processes, including cell apoptosis, proliferation and differentiation. miR-299 has been reported to be upregulated in acute promyelocytic leukemia (APL); however, the function and mechanistic role of miR-299 in APL remains unknown. The present study demonstrated mir-299 significantly induced cell growth and cell cycle progression at the G1/S transition in APL cells. Notably, the present study revealed that miR-299-5p induces these effects, whereas miR-299-3p does not. Additional studies demonstrated that in APL cells the tumor suppressor p21Cip1/Waf1 is a downstream target of miR-299; miR-299 binds directly to the 3' untranslated region of p21Cip1/Waf1, and reduces protein, but not mRNA, levels of p21Cip1/Waf1. The present findings demonstrate that miR-299 exerts growth-promoting effects in APL cells through the suppression of p21Cip1/Waf1. Overall, the present study demonstrates that p21Cip1/Waf1 is a direct functional target of miR-299 in APL.

Flavonoid derivative exerts an antidiabetic effect via AMPK activation in diet-induced obesity mice.

In our previous study, a derivative of tiliroside, 3-O-[(E)-4-(4-ethoxyphenyl)-2-oxobut-3-en-1-yl]kaempferol (Fla-OEt) significantly enhanced glucose consumption in insulin resistant HepG2 cells. This article deals with the antihyperglycemic and antihyperlipidemic effects of Fla-OEt in diet-induced obesity (DIO) mice. Daily administration of Fla-OEt significantly decreased oral glucose tolerance test, intraperitoneal insulin tolerance test and serum lipids. Hyperinsulinemic-euglycemic clamp and the ratio of high-density-lipoprotein/low-density-lipoprotein with Fla-OEt treatment were increased comparing with high-fat diet (HFD) group, so lipid metabolism was improved. Histopathology examination showed that the Fla-OEt restored the damage of adipose tissues and liver in DIO mice. Moreover, compared with HFD group, Fla-OEt treatment significantly increased the phosphorylation of AMPK and ACC in adiposity tissues, liver, and muscles. The mechanism of its action might be the activation of AMPK pathway. It appears that Fla-OEt is worth further study for development as a lead compound for a potential antidiabetic agent.

Anti-obesity and anti-diabetic effects of flavonoid derivative (Fla-CN) via microRNA in high fat diet induced obesity mice.

3-O-[(E)-4-(4-cyanophenyl)-2-oxobut-3-en-1-yl]kaempferol (Fla-CN), a semi-synthesized flavonoid derivative of tiliroside, reduces whole-body adiposity, ameliorates metabolic lipid disorder, improves insulin sensitivity and benefits other disorders characterized by insulin resistance in high fat diet induced obesity mice. The improvement of insulin sensitivity and the reduction of weight gain are correlated with the changes of leptin and adiponectin levels. As a result, Fla-CN treatment could increase the expressions of pAMPK and miR-27 in the liver and adipose tissues. Meanwhile, we discovered that the expressions of various adipogenesis genes were downregulated, which were target genes of miR-27. This is the first report for the action of miR-27 by flavonoid derivative in rodents. The action of Fla-CN might be through multiple approaches including AMPK activation and enhancement in miR-27 expression.

[Expression and Clinical Significance of Bmi-1 and P14 in Extranodal NK/T-cell Lymphoma].

OBJECTIVE: This study was aimed to investigate the expression and clinical significance of Bmi-1 and P14 in extranodal NK/T-cell lymphoma (ENKTCL) tissue. METHODS: Maxvision immunohistochemistry technique was used to detect the expression level of Bmi-1 and P14 in the tissues of 21 patients with ENKTCL and 11 normal lymph nodes. The correlation of Bmi-1 or P14 expression with the clinical features and the correlation between Bmi-1 and P14 expression were analyzed. RESULTS: The expression of Bmi-1 protein was higher in tissues of ENKTCL than that in tissues of lymph nodes, and the Bmi-1 expression levels did not correlate with patients' sex, age, lactate dehydrogenase (LDH), International Prognostic Index (IPI) scores and B symptoms (P > 0.05), except for clinical stage (P < 0.05). The P14 protein expression level was lower in ENKTCL tissues than in normal lymph node tissues, which did not correlate with age, sex, LDH, IPI scores, clinical stage and B symptoms. Correlation test showed a negative correlation between Bmi-1 and P14 (r = -0.472, P = 0.031). CONCLUSION: Bmi-1 protein over-expresses in ENKTCL tissues that may display a negative-regulation effect on P14 in the genesis and progress of ENKTCL.

[Growth Inhibition of Multiple Myeloma Cells Caused by MicroRNA-15a and Its Mechanisms].

OBJECTIVE: To explore the effect and possible mechanisms of miR-15a on growth of multiple myeloma(MM) cells. METHODS: MM cell lines (U266 and RPMI8226) were transfected by lentiviral particles. MM stable cell lines were selected and collected by flow cytometry (FCM). Proliferation of MM cells before and after miR-15a high expression was detected by CCK-8 method. Apoptosis of MM cells before and after miR-15a high expression was detected by AO/EB dying, Hoechst 33258 dying and FCM, respectively. Cell cycle of MM cells before and after miR-15a high expression was detected by FCM. The expressions of miR-15a, BMI-1 and BCL-2 mRNA of MM cells before and after miR-15a high expression were detected by real-time PCR. The expressions of BMI-1 protein of MM cells before and after miR-15a high expression were detected by Western blot. RESULTS: MM stable cell lines with miR-15a high expression was acquired. CCK-8 result showed that high expression of miR-15a could inhibit growth of MM cells (U266 and RPMI8226). AO/EB dying, Hoechst 33258 dying and FCM testing results showed that high expression of miR-15a could significantly induce apoptosis of MM cells (U266 and RPMI8226). The apoptosis rates of U266 and RPMI8226 cells in high expression group and control group were 90.52% vs 37.08% and 59.40% vs 44.17%, respectively. Meanwhile, FCM testing results showed that high expression of miR-15a could induce G1 arrest of MM cells (U266 and RPMI8226), which proportion of G1 phase were 41.50%±0.64%, 45.31%±0.77%, respectively. Real-time PCR results showed that during the growth inhibition process of MM cells caused by miR-15a high expression, the expression of BCL-2 mRNA decreased, but there was no significant changes in the expression of BMI-1 mRNA, while the expression of BMI-1 protein decreased significantly. CONCLUSION: High expression of miR-15a can induce cell cycle arrest and apoptosis of MM cells, then inhibit their growth. The mechanisms may be related with the negative regulation of BMI-1 and BCL-2 genes in post-transcription level caused by miR-15a.

The intestinal fatty acid binding protein-2 Ala54Thr polymorphism is associated with diabetic retinopathy in Chinese population.

OBJECTIVE: Endothelial dysfunction which is induced by serum saturated fatty acids increasing is one of pathogenesis of diabetic retinopathy (DR). The intestinal fatty acid binding protein-2 (FABP2) Ala54Thr polymorphism results in serum saturated fatty acids elevating. In the present study, we assessed the association of FABP2 gene polymorphism (Ala54Thr) with DR in Chinese population. MATERIALS/METHODS: In this case-control association study, 810 T2DM patients were recruited. 420 patients with retinal neovascularization, microneurysms and hemorrhages were considered as cases (DR) and 390 patients with T2DM and no clinical signs of retinopathy (DNR), were recruited as controls. Genotypes for FABP2(Ala54Thr) polymorphisms were assessed with the PCR-RFLP method. RESULTS: A significant difference in genotype distribution and allele frequency was observed between cases and controls. Patients with DR had significantly higher frequency of the Ala/Thr + Thr/Thr genotypes compared to DNR group [62.6% vs. 46.2%; OR (95% CI), 1.95 (1.48-2.59); p < 0.001]. The DR group showed a significantly higher frequency of the the Thr allele compared to the DNR group [39.5% vs. 29.4%; OR (95% CI), 1.56 (1.16-2.09); p = 0.003]. Binary logistic analyses showed FFA levels (p = 0.014) and Ala54Thr (p = 0.011) were independent correlates of the presence of DR. CONCLUSIONS: We examined that FABP2 polymophism on the Ala54Thr is significant and independent associated with DR.

[Anti-leukemia mechanism of miR-17 and miR-20a silencing mediated by miRNA sponge].

This study was aimed to quantitatively detect the expression levels of pre-miR-17 and pre-miR-20a in acute leukemia patients and eight kinds of leukemia cell lines, and to investigate the anti-leukemia mechanism of miR-17 and miR-20a silence mediated by miRNA Sponge. Quantitative real-time PCR was used to detect the mRNA expression levels of pre-miR-17 and pre-miR-20a in patients with various types of leukemia and leukemia cell lines. The Jurkat cells over-expressing miR-17 and miR-20a were transfected with recombinant lentivirus-transfecting units targeted at miR-17 and miR-20a plus 6 µg/ml of polybrene. Then the proliferation ability and cell cycle of Jurkat cells was evaluated by CCK-8 and flow cytometry respectively. The results showed that the expression level of pre-miR-17 and pre-miR-20a in all leukemia patients was significantly higher than that in normal group(P < 0.05), the expression of pre-miR-17 and pre-miR-20a in acute lymphoid leukemia was significantly higher than that in acute myeloid leukemia(P < 0.05), and the pre-miR-17 and pre-miR-20a expression level did not correlate significantly with high white blood cell count>20.0×10(9)/L(P > 0.05). The miR-17 and miR-20a silencing mediated by miRNA Sponge led to a significant decrease of cell growth, restored G1 accumulation and increase of cell apoptosis. It is concluded that the expression of miR-17 and miR-20a is upregulated in leukemia patients, which may contribute to leukemogenesis. Over-expressed miR-17 and miR-20a promote cell growth and cell cycle progression, and inhibit apoptosis through negatively-regulating P21 and E2F1 after-transcriptionally.

Liraglutide enhances glucose transporter 4 translocation via regulation of AMP-activated protein kinase signaling pathways in mouse skeletal muscle cells.

OBJECTIVE: Liraglutide is an anti-diabetic drug and human glucagon-like peptide-1 (GLP-1) analog that primarily functions in the pancreas. However, its extra-pancreatic functions are not clear. Skeletal muscle tissue is an important determinant of blood glucose and cells take in approximately 80% of dietary glucose via glucose transporter 4 (GLUT4) on the plasma membrane. Insulin and muscle contraction are two physiological stimuli of GLUT4 translocation to the cell membrane from intracellular storage compartments, but the signaling mechanisms that mediate these processes are different. AMP-activated protein kinase (AMPK) and Akt are the key signal molecules mediating the effects of muscle contraction and insulin, respectively, on GLUT4 translocation. Here, we investigate the effect of liraglutide on GLUT4 translocation and the roles of AMPK and Akt in this mechanism in skeletal muscle cells by stably expressing GLUT4myc with an exofacial myc-epitope C(2)C(12)-GLUT4myc. MATERIALS/METHODS: The cell surface GLUT4myc levels were determined by an antibody-coupled colorimetric assay. The phosphorylation levels of AMPK, Akt, AS160, TBC1D1, and GLUT4 were determined by western blotting. The cAMP levels were measured by an ELISA kit. siRNA was transfected with Lipofectamine 2000. Analysis of variance (ANOVA) was used for data analysis. RESULTS: Liraglutide stimulated GLUT4 translocation in C(2)C(12)-GLUT4myc myotubes. Liraglutide increased the intracellular cAMP levels and the phosphorylation of AMPK, AS160, and TBC1D1. Akt phosphorylation and GLUT4 expression were not affected. Inhibition of AMPK by siRNA or Compound C reduced liraglutide-induced GLUT4 translocation. CONCLUSION: Our results suggest that liraglutide may induce GLUT4 translocation by activation of AMPK in muscle cells.

ShRNA-mediated Bmi-1 silencing sensitizes multiple myeloma cells to bortezomib.

The introduction of bortezomib has resulted in a paradigm shift in the treatment of multiple myeloma (MM) and has contributed to the improved survival of patients with MM. Inevitably, resistance to therapy develops, and thus the clinical efficacy of bortezomib is hampered by drug resistance. The oncogene B-cell­specific Moloney murine leukemia virus insertion site­1 (Bmi-1) has been implicated in the pathogenesis of various human malignancies. Furthermore, RNA interference (RNAi)­mediated Bmi-1 silencing has been shown to sensitize tumor cells to chemotherapy and radiation. The role of Bmi-1 in influencing the response to bortezomib therapy has not been investigated to date. In the present study, Bmi-1 was silenced in two MM cell lines (U266 and RPMI8226) using short hairpin RNA (shRNA) targeting Bmi-1 (shBmi-1). A cell counting kit-8 (CCK-8) assay was performed to analyze cell proliferation and evaluate the 50% inhibitory concentration (IC50) values of bortezomib. Cell cycle progression and apoptosis were analyzed by flow cytometry (FCM), and the mRNA and protein expression of associated genes (Bmi-1, p14, p21, Bcl-2 and Bax) was quantified by RT-qPCR and western blot analysis, respectively. The IC50 values significantly decreased in the cells transfected with shBmi-1 (p<0.05). The depletion of Bmi-1 sensitized the MM cells to bortezomib, which increased the G1 phase duration and enhanced bortezomib­induced apoptosis (p<0.05). The expression of p21 and Bax (apoptosis inducer) was upregulated, whereas that of the anti-apoptotic protein, Bcl-2, was downregulated in the Bmi-1­silenced cells (p<0.05). The depletion of Bmi-1 enhanced the sensitivity of MM cells to bortezomib by inhibiting cell proliferation and inducing cell cycle arrest and apoptosis. Our data suggest that Bmi-1 may serve as an important novel therapeutic target in MM.

Effects of varying degrees of intermittent hypoxia on proinflammatory cytokines and adipokines in rats and 3T3-L1 adipocytes.

OBJECTIVES: Intermittent hypoxia (IH), resulted from recurring episodes of upper airway obstruction, is the hallmark feature and the most important pathophysiologic pathway of obstructive sleep apnea (OSA). IH is believed to be the most important factor causing systemic inflammation. Studies suggest that insulin resistance (IR) is positively associated with OSA. In this study, we hypothesized that the recurrence of IH might result in cellular and systemic inflammation, which was manifested through the levels of proinflammatory cytokines and adipokines after IH exposure, and because IR is linked with inflammation tightly, this inflammatory situation may implicate an IR status. METHODS: We developed an IH 3T3-L1 adipocyte and rat model respectively, recapitulating the nocturnal oxygen profile in OSA. In IH cells, nuclear factor kappa B (NF-κB) DNA binding reactions, hypoxia-inducible factor-1α (HIF-1α), glucose transporter-1 (Glut-1), necrosis factor alpha (TNF-α), interleukin (IL) -6, leptin, adiponectin mRNA transcriptional activities and protein expressions were measured. In IH rats, blood glucose, insulin, TNF-α, IL-6, leptin and adiponectin levels were analyzed. RESULTS: The insulin and blood glucose levels in rats and NF-κB DNA binding activities in cells had significantly statistical results described as severe IH>moderate IH>mild IH>sustained hypoxia>control. The mRNA and protein levels of HIF-1α and Glut-1 in severe IH group were the highest. In cellular and animal models, both the mRNA and protein levels of TNF-α, IL-6 and leptin were the highest in severe IH group, when the lowest in severe IH group for adiponectin. CONCLUSIONS: Oxidative stress and the release of pro-inflammatory cytokines/adipokines, which are the systemic inflammatory markers, are associated with IH closely and are proportional to the severity of IH. Because IR and glucose intolerance are linked with inflammation tightly, our results may implicate the clinical relationships between OSA and IR.