Exploring the structural determinants of novel xanthine derivatives as A2B adenosine receptor antagonists: a computational study

Adenosine is a ubiquitous endogenous nucleoside that controls numerous physiological functions via interacting with its specific G-coupled receptors. Activation of adenosine receptors (AdoRs), particularly A_2B AdoRs promotes the release of inflammatory cytokines; reduces vascular permeabilization and induces angiogenesis, thereby making A_2B AdoR becomes a potentially pharmacological target for drug development. Presently, for investigating the structural determinants of 164 xanthine derivatives as A_2B AdoR antagonists, we performed an in silico study integrating with 3D-QSAR, docking and molecular dynamics (MD) simulation. The obtained optimal model shows strong predictability (Q²?=?0.647, R²_ncv?=?0.955, and R²_pred?=?0.848). Additionally, to explore the binding mode of the ligand with A_2B AdoR and to understand their binding mechanism, docking analysis, MD simulations (20?ns), and the calculation of binding free energy were also carried out. Finally, the structural determinants of these xanthine derivatives were identified and a total of 20 novel A_2B AdoR antagonists with improved potency were computationally designed, and their synthetic feasibility and selectivity were also evaluated. The information derived from the present study offers a better appreciation for exploring the interaction mechanism of the ligand with A_2B AdoR, which could be helpful for designing novel potent A_2B AdoR antagonists.

Communicated by Ramaswamy H. Sarma     

Differential protein expression profiling by iTRAQ-2D-LC-MS/MS of rats treated with oxaliplatin

Clinical application of oxaliplatin, a platinum-based chemotherapeutic agent, in cancer, especially colorectal cancer, is widely used. However, oxaliplatin-induced peripheral neurotoxicity (OIPN) has a high incidence, and to date, there have been few detailed studies on pathogenesis and treatment mechanisms. The present study was performed by using a proteomic approach to explore protein expression profiling of rats treated with oxaliplatin by multiplex isobaric tags for relative and absolute quantification labeling and two-dimensional liquid chromatography-tandem mass spectrometry. There were 74 proteins that showed different expression in sciatic nerve between control rats and OIPN model rats, with 53 upregulated proteins and 21 downregulated proteins detected in OIPN groups compared with control groups. On the basis of Gene Ontology clustering, these proteins were associated with biological processes (eg, muscle contraction, muscle system process, and skeletal muscle contraction), cellular component (eg, myofibril, contractile fiber, and contractile fiber part) and molecular function (structural constituent of muscle, hydro-lyase activity, and calcium ion binding). On the basis of Kyoto Encyclopedia of Genes and Genomes pathway database, these proteins were associated with African trypanosomiasis, malaria, nitrogen metabolism, etc. Real-time polymerase chain reaction, Western blot as well as immunohistochemistry analysis was performed to examine the expression of partially differential protein. In conclusion, our study establishes a protein expression profile of oxaliplatin-induced rats and mechanisms leading to OIPN development, and will be useful for developing novel diagnostic biomarkers and aiding in the prevention and control of OIPN.     

MicroRNA-328 ameliorates oxidized low-density lipoprotein-induced endothelial cells injury through targeting HMGB1 in atherosclerosis

Atherosclerosis has been recognized as a chronic inflammatory disease, which can harden the vessel wall and narrow the arteries. MicroRNAs exhibit crucial roles in various diseases including atherosclerosis. However, so far, the role of miR-328 in atherosclerosis remains barely explored. Therefore, our study concentrated on the potential role of miR-328 in vascular endothelial cell injury during atherosclerosis. In our current study, we observed that oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) apoptosis and inhibited cell viability dose-dependently and time-dependently. In addition, indicated dosage of ox-LDL obviously triggered HUVECs inflammation and oxidative stress process. Then, it was found that miR-328 in HUVECs was reduced by ox-LDL. HUVECs apoptosis was greatly repressed and cell survival was significantly upregulated by overexpression of miR-328. Furthermore, mimics of miR-328 rescued cell inflammation and oxidative stress process induced by ox-LDL. Oppositely, inhibitors of miR-328 strongly promoted ox-LDL-induced endothelial cells injury in HUVECs. By using bioinformatics analysis, high-mobility group box-1 (HMGB1) was predicted as a downstream target of miR-328. HMGB1 has been reported to be involved in atherosclerosis development. The correlation between miR-328 and HMGB1 was validated in our current study. Taken these together, it was implied that miR-328 ameliorated ox-LDL-induced endothelial cells injury through targeting HMGB1 in atherosclerosis.     

Retracted: Advanced glycation end-products induce oxidative stress through the Sirt1/Nrf2 axis by interacting with the receptor of AGEs under diabetic conditions

Despite the administration of exogenous insulin and other medications used to control many aspects of diabetes mellitus (DM), increased oxidative stress has been increasingly acknowledged in DM development and complications. Therefore, this study aims to investigate the role of advanced glycation end-products (AGEs) in oxidative stress (OS) of thyroid cells in patients with DM. Patients with DM with or without thyroid dysfunction (TD) were enrolled. Thyroid toxic damage was induced by adding AGE-modified bovine serum albumin (AGE-BSA) to normal human thyroid follicular epithelial cells. The cell viability, cell cycle, and cell apoptosis, as well as the content of reactive oxygen species (ROS), catalase (CAT), and malondialdehyde (MDA) in cells were measured. Thyroid hormones, T3, T4, FT3, and FT4 levels were measured by enzyme-linked immunosorbent assay. Receptor for advanced glycation end products (RAGE), sirtuin1 ( Sirt1), and NF-E2-related factor 2 ( Nrf2) expressions were detected, and the mitochondrial membrane potential was measured. We found increased AGEs in the serum of DM patients with TD. By increasing AGE-BSA concentration, cell viability; the thyroid hormones T3, T4, FT3, and FT4 levels; and mitochondrial membrane potential all significantly decreased. However, the increase in AGE-BSA concentration led to an increase in cell apoptosis, RAGE, and nuclear factor-κB expressions but produced the opposite effect on Sirt1, Nrf2, and heme oxygenase-1 expressions, as well as a decrease in antioxidant response element protein levels. The AGE-BSA increased ROS and MDA levels and reduced CAT level in normal human thyroid follicular epithelial cells on a dose independence basis. Our results demonstrated that AGEs-mediated direct increase of RAGE produced OS in thyroid cells of DM by inactivating the Sirt1/Nrf2 axis.     

Serum exosomal miR-210 as a potential biomarker for clear cell renal cell carcinoma

Exosomal microRNAs (miRNAs) are suggested to reflect molecular changes occurring in their cells of origin and are potential indicators in the early detection of cancers. This study aimed to determine whether certain exosomal miRNAs from tumor tissue can be used as noninvasive biomarkers for clear cell renal cell carcinoma (ccRCC). Based on ccRCC miRNA expression profiles and the literature, we selected six miRNAs (miR-210, miR-224, miR-452, miR-155, miR-21, and miR-34a) and analyzed their expression in tissues, sera, and serum exosomes through quantitative real-time polymerase chain reaction in hypoxia-induced (with CoCl₂) renal cell lines. miR-210, miR-224, miR-452, miR-155, and miR-21 were upregulated in tumor tissues compared with normal tissues. Serum miR-210 and miR-155 levels were higher in patients with ccRCC than in healthy controls (HCs). Furthermore, only exosomal miR-210 was significantly upregulated in patients with ccRCC than in HCs. Moreover, receiver operating characteristic (ROC) curve analysis revealed an area under the ROC curve of 0.8779 (95% confidence interval, 0.7987-0.9571) and a sensitivity and specificity of 82.5% and 80.0%, respectively. Moreover, exosomal miR-210 was upregulated at an advanced stage, and Fuhrman grade and metastasis decreased significantly one month after surgery. Acute hypoxia exposure activates miR-210 and release of exosomes with upregulated miR-210 in both normal and tumor RCC cell lines and interferes with vacuole membrane protein 1 mRNA expression, especially in the metastatic ccRCC cell line. In conclusion, Serum exosomal miR-210 originating from tumor tissue has potential as a novel noninvasive biomarker for the detection and prognosis of ccRCC.     

SNHG15 functions as a tumor suppressor in thyroid cancer

Small nucleolar RNA host gene 15 (SNHG15) has been suggested to be overexpressed, and function as an oncogenic long noncoding RNA (lncRNA) in various types of human malignancies. However, the expression status and function of SNHG15 were still unknown in thyroid cancer. In our study, we assessed the expression status and clinical value in thyroid cancer samples, and explored the effect of SNHG15 on thyroid cancer cell proliferation, migration, and invasion. In results, SNHG15 expression was downregulated in thyroid cancer tissues and cells, and correlated with age, pathology classification, clinical stage, tumor size, distant metastasis, and disease-free survival. The in vitro studies suggested SNHG15 overexpression suppressed cell proliferation, migration, and invasion in thyroid cancer. In summary, SNHG15 serves as tumor suppressive role in thyroid cancer.     

Prognostic evaluation of NANOG and OCT4 expression for posttransplantation hepatocellular carcinoma recurrence

Postoperative hepatocellular carcinoma (HCC) recurrence and metastasis throw great threaten to its overall survival (OS). This paper focus on exploring the prognostic significance of NANOG and OCT4 expression in HCC recurrence and OS after liver transplantation. Eighty-six patients who meet University of California San Francisco (UCSF) criteria and underwent liver transplantation in Tianjin First Central Hospital between August 2010 and August 2013 were included. Expression of NANOG and OCT4 was determined by immunohistochemistry. The relationships between NANOG and OCT4 expression with tumor recurrence, tumor count, histology stage, lymph node metastasis (LNM) and microvascular invasion (MVI) were explored through the χ² test and Cox regression analysis. We found that 19/26 and 20/24 patients with positive expression of NANOG and OCT4 relapsed. Combination of NANOG and OCT4 expression was indicated as valuable prognostic signature for HCC recurrence prediction (P < 0.0011). Besides, we identified other key factors with significant correlations with recurrence, such as LNM (P = 0.011) and MVI (P = 0.024). Strikingly, recurrence sites could significantly affect recurrence time (P = 0.0062) and patients with recurrence in transplanted liver have longer recurrence time. In conclusions, we analyzed the relationships between NANOG/OCT4 expression, clinicopathology features, HCC recurrence, and OS after liver transplantation for the first time. Combination of NANOG, OCT4, LNM, histopathological stage, and MVI may be predictor for HCC recurrence posttransplantation. Comprehensive of histopathological stage grade and LNM were considered as prognosis factor for OS after liver transplantation. This should be helpful for treatment method selection for HCC patients after liver transplantation.     

PTPN2 induced by inflammatory response and oxidative stress contributed to glioma progression

Malignant glioma remains the most frequent form of primary brain tumors all over the world. The gliomagenesis is characterized by various molecular processes such as neoplastic transformation, dysregulation of the cell cycle, and angiogenesis. Among these biomolecular events, the existence of inflammation and oxidative stress pathways in the development of glioma has been reported. PTPN2 is associated with several inflammatory disorders. However, the biological role of PTPN2 in inflammation responses and oxidative stress pathways involved in glioma remains poorly known. Here, we focused on its function in glioma development. Here, we observed that PTPN2 was significantly increased in glioma especially in a grade-dependent manner. Meanwhile, interferon-γ and tumor necrosis factor-α, which have been identified as crucial inflammation cytokines, were able to trigger PTPN2 expression in a dose-dependent course in T98G cells. Then, we found that PTPN2 was oxidated and inactivated by H₂O₂. Meanwhile, H₂O₂ induced glioma cell colony formation capacity and increased ki-67 expression confirmed by flow cytometry assay. Finally, T98G cells were transfected with PTPN2 shRNA and it was shown that knockdown of PTPN2 obviously inhibited T98G cell colony formation and induced cell apoptosis. In summary, our findings indicated that PTPN2 could be induced by inflammatory response and oxidative stress and its deficiency depressed glioma cell growth.