[AMP-activated protein kinase (AMPK) as therapeutic target]

Impact of titanium dioxide nanoparticles on intestinal community in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute colitis mice and the intervention effect of vitamin E

Titanium dioxide nanoparticles (TiO2-NPs) are widely applied as additives in foods due to their excellent whitening and brightening capability. Although the toxicity and antibacterial activity of TiO2-NPs have been extensively studied, their impact on the gut microbiota in vivo still remains unclear, especially in animals with gastrointestinal disorders. In the present study, healthy mice and TNBS-induced colitis mice were administered with TiO2-NPs (38.3 ± 9.3 nm) orally at a dose of 100 mg per kg bw daily for 10 days to study the impact of TiO2-NPs on the gut microbiota and colitis development. Moreover, the mechanism of TiO2-NPs on the gut microbiota was also discussed when the colitis mice were additionally administered with vitamin E to remove ROS. Changes in the microbiota community structure and gut-associated function prediction were analyzed through bioinformatics. The result showed that the oral administration of TiO2-NPs mitigated colitis symptoms by reducing the DAI and CMDI scores and TNF-α level. Furthermore, 16S rDNA sequencing analysis showed that the structure and function prediction of gut microbiota could be modified in healthy mice and colitis mice after exposure to TiO2-NPs, but the opposite physiological effect occurred since the dominant flora varied in these two groups. Moreover, vitamin E intervention did not change the effects of TiO2-NPs on the microbiota community structure and gut-associated function, which indicates that the mechanism of the biological effects of TiO2-NPs on the gut microbiota may not be associated with their ability to induce the generation of ROS. In summary, our work firstly found that TiO2-NPs could regulate the gut microbiota of colitis mice and participate in the mitigation of TNBS-induced acute colitis, and the capability of TiO2-NPs to induce the generation of ROS inducement did not contribute to this process.

Polyphenols and Other Bioactive Compounds of Sideritis Plants and Their Potential Biological Activity

Due to the growing problem of obesity associated with type 2 diabetes and cardiovascular diseases, causes of obesity are extensively investigated. In addition to a high caloric diet and low physical activity, gut microbiota disturbance may have a potential impact on excessive weight gain. Some reports indicate differences in the composition of the intestinal microflora of obese people in comparison to lean. Bioactive compounds of natural origin with beneficial and multifaceted effects on the body are more frequently used in prevention and treatment of many metabolic diseases including obesity. Sideritis scardica is traditionally consumed as mountain tea in the Balkans to strengthen the body and improve mood. Many reports indicate a positive effect on digestive system, weight loss, and prevention of insulin resistance. Additionally, it exhibits antioxidant activity and anti-inflammatory effects. The positive effect of Sideritis scardica extracts on memory and general cognitive abilities is indicated as well. The multilevel positive effect on the body appears to originate from the abundant occurrence of phenolic compounds, especially phenolic acids in Sideritis scardica extracts. However, mechanisms underlying their action require careful discussion and further research. Therefore, the objective of this review is to summarize the available knowledge on the role and mechanism of action of biologically active compounds of Sideritis scardica and other related species from the genus Sideritis.

SWI/SNF chromatin remodeling complex and glucose metabolism are deregulated in advanced bladder cancer

Bladder cancer (BC) is a frequently diagnosed malignancy affecting predominantly adult and elderly populations. It is expected that due to the longer life time, BC will become even more frequent in the future; thus in consequence, it will represent serious health problem of older society part. The treatment of advanced BC is mostly ineffective due to its very aggressive behavior. So far, no effective targeted therapy is used for BC treatment. Here, we found that BC is characterized by lower protein levels of BRM, INI1, and BAF155 main subunits of SWI/SNF chromatin remodeling complex (CRC) which is involved in global control of gene expression and influences various important cellular processes like: cell cycle control, apoptosis, DNA repair, etc. Moreover, the expression of SMARCA2, a BRM encoding gene, strongly correlated with BC metastasis and expression of such metabolic genes as PKM2 and PRKAA1. Furthermore, the analysis of T24 and 5637 commonly used BC cell lines revealed different expression levels of metabolic genes including FBP1 gene encoding Frutose-1,6-Bisphosphatase, an enzyme controlling glycolysis flux and gluconeogenesis. The tested BC cell lines exhibited various molecular and metabolic alterations as well as differential glucose uptake, growth rate, and migration potential. We have shown that BRM subunit is involved in the transcriptional control of genes encoding metabolic enzymes. Moreover, we found that the FBP1 expression level and the SWI/SNF CRCs may serve as markers of molecular subtypes of BC. Collectively, this study may provide a new knowledge about the molecular and metabolic BC subtypes which likely will be of high importance for the clinic in the future.

Expression of Irisin/FNDC5 in Cancer Cells and Stromal Fibroblasts of Non-small Cell Lung Cancer

Background: Recent in vitro studies have indicated that irisin inhibits proliferation, migration and epithelial-mesenchymal transition. Irisin expression has not been studied in tumour tissues of non-small cell lung cancer (NSCLC) patients yet. The aim of the study was to determine the irisin expression in NSCLCs in comparison to the clinicopathological factors and expression of TTF-1, p63 and Ki-67. Material and methods: Tissue microarrays with 729 NSCLC and 140 non-malignant lung tissue (NMLT) were used to perform immunohistochemical reactions. Laser Capture Microdissection (LCM) was used to collect cancer and stromal cells from NSCLCs. FNDC5 expression was tested for LCM samples, 75 NSCLCs and 25 NMLTs with the RT-PCR technique. Western-blot, immunofluorescence reaction and RT-PCR assays were performed on lung cancer cell lines. Results: Irisin expression was observed in NSCLC cancer cells and stromal fibroblasts. In cancer cells, irisin expression was decreased in higher grades (G) of malignancy, tumour size (T) and according to lymph node metastasis. In stromal cells, irisin expression was increased in higher G and advanced T. A shorter overall survival was observed in patients with higher irisin expression in NSCLC stromal cells. Conclusions: Irisin expression in stromal fibroblasts may influence cancer cell proliferation and may be a prognostic factor for survival in NSCLC.

Salidroside enhances the anti-cancerous effect of imatinib on human acute monocytic leukemia via the induction of autophagy-related apoptosis through AMPK activation

As the typical tyrosine kinase inhibitor, imatinib has been the first-line antineoplastic agent for both chronic myeloid leukemia and acute lymphoblastic leukemia. However, a large number of patients are still resistant to the benefits of imatinib, and they have a dissatisfactory prognosis. Salidroside, a compound that is extracted from natural plants, has been reported to have an excellent anticancer effect and few side effects. In the present study, we have developed a new combination therapy strategy of salidroside and imatinib for combating the growth of acute lymphoblastic leukemia. As demonstrated by the anti-proliferation assay, salidroside exhibited excellent cytotoxicity against myeloid leukemia cells. Moreover, cells treated by the combination therapy of salidroside and imatinib displayed a clear lower growth rate than cells only treated by imatinib, indicating that salidroside has a positive effect on enhancing the cytotoxicity of imatinib against leukemia cells. Subsequently, the underlying mechanisms were investigated. The results revealed that autophagy marker proteins in leukemia cells, including LC3, p62, and Beclin1, displayed a significant expression change after treating them with salidroside plus imatinib, with the levels of LC3 and Beclin1 dramatically increasing while the expression of p62 was significantly decreased. Moreover, an obvious down-regulation of p-PI3K, p-AKT and p-mTOR expression levels in leukemia cells after treatment with salidroside plus imatinib suggested that the PI3K/mTOR pathway plays an important role in the process of cell apoptosis induced by salidroside or imatinib. Further studies showed that pre-incubating the cells with an autophagy inhibitor dramatically inhibited the ability of imatinib to induce autophagy, but did not inhibit the ability of salidroside. The underlying causes were subsequently explored and the results showed that silencing AMPKα1, the most important regulator of autophagy, dramatically attenuates the ability of salidroside to induce cell apoptosis. These results together indicated that salidroside enhances the cytotoxicity of imatinib on acute monocytic leukemia via the induction of autophagy-related apoptosis through AMPK activation. The unique advantages of combination therapy were further confirmed by in vivo experiments, with the tumor-bearing cells treated with salidroside plus imatinib achieving the best anti-tumor effect.

Cpt1c regulated by AMPK promotes papillary thyroid carcinomas cells survival under metabolic stress conditions

Background: Cancer cells have to take metabolic transformation in tumor progression when facing need of increased energy and adequate vascularization. However, molecular mechanism is not fully known. In this study, we showed that expression of carnitine palmitoyltransferase 1C (Cpt1c), as a member of the gate-keeper enzymes , which transferring long-chain fatty acids into mitochondria to further oxidation, which is regulated by AMPK promotes papillary thyroid carcinomas cells survival under metabolic stress conditions.

Methods: Firstly, we used qRT-PCR to detect expression of Cpt1c in papillary thyroid carcinomas tissues compared with paired normal tissues. Secondly, to evaluate whether Cpt1c is induced under metabolic stress, models of hypoxia (0.2% oxygen) and glucose deprivation for cultured papillary thyroid carcinomas cells were established. Lastly, KTC-1 cells were treated with AICAR (as an agonist of AMPK) and Compound C (as an inhibitor of AMPK) to investigate the correlation of AMPK activity with Cpt1c expression under metabolic stress.

Results: Cpt1c is higher in papillary thyroid carcinomas tissues compared with paired normal tissues. Furthermore, Cpt1c up-regulation promotes cancer cell growth and metastasis. In addition, the results showed that Cpt1c expression is induced by metabolic stress, including hypoxia and low glucose treatment. Consistently, Cpt1c can protect cells from cancer cells death caused by hypoxia and low glucose. Lastly, Cpt1c expression is regulated by AMPK activity.

Conclusion: Here we describe that induction of Cpt1c expression facing metabolic stress in papillary thyroid carcinomas is at least partly regulated by AMPK activity and ultimately contribute to development and progression of papillary thyroid carcinomas.

Combination therapy with oleanolic acid and metformin as a synergistic treatment for diabetes

AIMS AND BACKGROUND

Type 2 diabetes is a chronic disease that cannot be treated adequately using the known monotherapies, especially when the disease progresses to an advanced stage. In this study, we explore the possibility of treating the disease with a novel combination approach of oleanolic acid (OA), a glycogen phosphorylase (GP) inhibitor, and metformin.

METHODS

Db/db mice were randomly divided into four groups: a db/db control group, db/db mice treated with OA (250 mg/kg), db/db mice treated with metformin (100 mg/kg), and db/db mice treated with a combination of OA and metformin. All mice were treated for four weeks. The effects of the treatments on glucose homeostasis were measured using an OGTT, an assessment of insulin sensitivity and signaling in the liver, and the hepatic glucose production.

RESULTS

Combination therapy with OA and metformin significantly reduced the blood glucose and insulin levels and improved the liver pathology compared with that for the monotherapy in the db/db diabetic mouse model. We also found that the combination therapy significantly increased the mRNA expression of glycogen synthesis and decreased the GP, PGC-1α, PEPCK1, and G-6-Pase levels. In addition, the combination therapy with OA and metformin significantly increased the phosphorylation of AKT, PI3K, AMPK, and ACC and decreased the protein expression levels of G-6-Pase, PEPCK1, and TORC compared with those for either monotherapy. The combination therapy also reduced the phosphorylation of mTOR and CREB.

CONCLUSIONS

Our results suggest that the combination therapy with OA and metformin has synergistic effects on the symptoms of db/db diabetic mice by improving glucose and insulin homeostasis.