Rituximab-induced HMGB1 release is associated with inhibition of STAT3 activity in human diffuse large B-cell lymphoma

Treatment with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) has greatly improved clinical outcomes in patients with diffuse large B-cell lymphoma (DLBCL) compared with CHOP. The mechanism of rituximab-induced cell death is poorly understood. We found that rituximab does not enhance the directly killing efficacy of CHOP, as tested on a panel of DLBCL cell lines. Rituximab induced a rapid release of HMGB1 (High mobility group protein B 1). This release is independent of cell death but significantly correlated with an inhibition on STAT3 activity. In the resting state, HMGB1 co-localizes and interacts with STAT3 in the nucleus of DLBCL cells. Treatment with rituximab breaks this binding and triggers HMGB1 release. Treatment with R-CHOP but not CHOP significantly increased plasma HMGB1 and decreased IL-10 concentrations in DLBCL patients compared with controls. The conditioned medium from rituximab-treated DLBCL cells is able to trigger dendritic cell maturation, phagocytosis, and IFN-g secretion by cytotoxic T cells. In conclusion, our results demonstrate that rituximab induces an inhibition on STAT3 activity, leading to increased HMGB1 release and decreased IL-10 secretion, which elicits immune responses, suggesting that indirect effects on the immune system rather than direct killing contribute to elimination of DLBCL.

MicroRNA-106b targets FUT6 to promote cell migration, invasion, and proliferation in human breast cancer

It is demonstrated that the maladjustment of microRNA (miRNA) plays significant roles in the occurrence and development of tumors. MicroRNA-106b-5p (miR-106b), a carcinogenic miRNA, is identified as a dysregulated miRNA in human breast cancer. In this article, the expression levels of miR-106b were discovered to be particularly higher in breast cancer tissues than that in the corresponding adjacent tissues. Accordingly, miR-106b was higher expressed in the breast cancer cell lines compared with that in the normal breast cell lines. Moreover, according to the data previously reported, increased expression of miR-106b was significantly associated with advanced clinical stages and poor prognosis in breast cancer. Fucosyltransferase 6 (FUT6), a member of the fucosyltransferase (FUT) family, was found to have a reduced expression in tissues or cells with higher level of miR-106b in breast cancer. Additionally, down-regulation of miR-106b increased the expression of FUT6 and resulted in an obvious decrease of cell migration, invasion, and proliferation in MDA-MB-231 cells. Furthermore, over-expressed FUT6 reversed the impacts of up-regulated miR-106b on cell migration, invasion, and proliferation in MCF-7 cells, indicating that FUT6 might be directly targeted by miR-106b and serve as therapeutic targets for breast cancer. In brief, our results strongly showed that the low expression of FUT6 regulated by miR-106b contributed to cell migration, invasion, and proliferation in human breast cancer. © 2016 IUBMB Life, 68(9):764-775, 2016.

[Oxidative damage related to PM2.5 exposure in human embryonic stem cell-derived fibroblasts]

OBJECTIVE

To study the oxidative damage of PM2.5 in human embryonic stem cells (EBf-H9 cells), and to provide a theoretical basis for revealing the adverse health effects of PM2.5 and the potential mechanisms, and also to provide a new alternative cell model for PM2.5 risk assessment.

METHODS

EBf-H9 cells were cultured with 0.00 (the constrast group) 3.91, 7.81, 15.63, 31.25, 62.50, 125.00 μg/cm(2) of PM2.5. CCK-8 kit was used to determine the survival rate of cells exposed to PM2.5 for 6 h. DCFH-DA probe was used to detect the total ROS content of cells exposed to PM2.5 for 1 h. The activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), and the content of lipid peroxides such as malondialdehyde (MDA) in cells exposed to PM2.5 for 6 h were detected by using the commercial kits. ANOVA model analyzed the statistical significance from the different concentration group.

RESULTS

The cytotoxicity results showed that the cell survival rate was decreased gradually with the increase of the concentrations of PM2.5, and the half inhibitory concentration (IC50) was 83.01 μg/cm(2). When the exposure concentration was 3.91, 7.81, 15.63, 31.25, 62.5 μg/cm(2), after exposure of PM2.5 1 h, the ROS florescence was 27.12±0.21, 54.03±0.50, 60.93±0.08, 61.36±1.00, 68.21±0.93, 78.27±1.26 (compared to control group 27.12±0.21, all P level<0.01). After exposure of PM2.5 6 h, the activities of T-SOD was (9.78±0.28), (8.59±0.22), (8.90±0.33), (7.46±0.71), (4.21±0.17) U/mg protein (F=98.881, compared to control group (11.77±0.63) U/mg protein, all P level<0.01). The activities of GSH-Px was (181.59±3.65), (153.33±1.69), (168.74±2.22), (81.56±0.56), (48.62±2.13) U/mg protein (compared to control group (273.90±6.50) mU/mg protein, all P level<0.01). And the content of MDA was (0.38±0.03), (0.43±0.09), (0.47±0.09), (0.65±0.10), (0.70±0.12) nmol/mg protein (compared to control group (0.27±0.02) nmol/mg protein, all P level<0.05).

CONCLUSION

PM2.5 exposure can decrease EBf-H9 cells viability, and improve the levels of lipid peroxidation. It may be due to induce EBf-H9 cells to increase the production of ROS and to make the cells appear oxidative stress, which lead to oxidative damage to cells. The present study reveals the mode of action of PM2.5 in terms of oxidative damage to EBf-H9 cells. It is also indicated that the cells may be a new alternative cell model for PM2.5 risk assessment.

miR-493-5p attenuates the invasiveness and tumorigenicity in human breast cancer by targeting FUT4

Breast cancer is a leading cause of cancer-related mortality among women. Altered fucosylation was found to be closely associated with tumorigenesis and metastasis of breast cancer. MicroRNAs (miRNAs) are important regulators of cell proliferation and metastasis, and aberrant miRNA expression has been observed in breast cancer. The present study aimed to evaluate the level of fucosyltransferase IV (FUT4) and miR-493-5p in breast cancer and investigate their relationship. In the present study, we demonstrated the differential expressional profiles of FUT4 and miR‑493-5p in 29 clinical breast cancer tissues, matched adjacent tissue samples and two breast carcinoma cell lines (MCF-7 and MDA-MB-231). Briefly, altered expression levels of FUT4 modified the invasive activities and tumorigenicity of the MCF-7 and MDA-MB-231 cells. Further study demonstrated that miR-493-5p plays a role as a suppressor in breast cancer cell invasion and tumorigenicity. Moreover, the expression levels of miR-493-5p were inversely proportional to those of FUT4 both at the mRNA and protein levels. Luciferase reporter assays confirmed that miR‑493-5p bound to the 3'-untranslated (3'-UTR) region of FUT4, and inhibited the expression of FUT4 in breast cancer cells. Taken together, our data suggest that FUT4 may have a potential role in the treatment of breast cancer, as well as miR-493-5p is a novel regulator of invasiveness and tumorigenicity of breast cancer cells through targeting FUT4. The miR-493-5p/FUT4 pathway has therapeutic potential in breast cancer.

Calcitonin gene-related peptide in aerobic exercise induces collateral circulation development in rat ischemia myocardium

PURPOSE

Aerobic exercise may offer favorable effects for coronary perfusion in the myocardial ischemia area, although the underlying molecular mechanisms remain unclear. This study was designed to investigate the effect of aerobic exercise on the collateral circulation in the ischemia myocardium and to evaluate calcitonin gene-related peptide (CGRP) changes during this process.

METHODS AND RESULTS

Wistar rats were randomly divided into 3 groups of 7 rats each: a sham operated group (Sham), a myocardial ischemia-only group (MI) and a MI plus aerobic exercise group (MI+AE). The rat myocardial ischemia model was established by injecting isoprenaline (2mg/kg, i.p.). The aerobic exercise training consisted of swimming (40min/d, 5d/wk) for 4 weeks. At the end-points, after echocardiographic analysis was performed, blood and ischemia myocardium samples were collected and analyzed by ELISA to quantify the CGRP protein. The dorsal root ganglia were isolated and analyzed by reverse transcription polymerase chain reaction (RT-PCR) to examine the CGRP mRNA expression, and ischemia myocardium capillary density was evaluated by immunohistochemistry. Our data showed that the capillary density in the left ventricle and heart function were significantly decreased with decreased CGRP production in the MI rats, which were reversed by aerobic exercise in the MI+AE rats.

CONCLUSION

These results indicate that aerobic exercise may alleviate myocardial ischemia through collateral circulation development with increased CGRP production. CGRP may play an important role in developing the collateral circulation.

Recent advances in the discovery of heparanase inhibitors as anti-cancer agents

Heparanase, an only endo-β-d-glucuronidase capable of cleaving heparan sulfate (HS) side chains at specific sites, contributes to remodeling of the extracellular matrix (ECM) and releasing of HS-linked growth factors, cytokines and signaling proteins. In addition, heparanase also plays an indispensable role in tumor angiogenesis, invasion and metastasis, indicating that it is a promising target for the development of antitumor drugs. Recent progress leads to three classes of heparanase inhibitors, including active analogs of endogenous substance, synthetic small molecule compounds and natural products. In this review, following an outline on the heparanase structure and function, an overview of the advancement of heparanase inhibitors as novel and potent anti-cancer agents will be given, especially introducing various existing heparanase inhibitors, as well as their inhibitory activities and mechanisms of action.

Isomers and their metabolites of endosulfan induced cytotoxicity and oxidative damage in SH-SY5Y cells

As an organochlorine insecticide, endosulfan has been widely banned or restricted, but it is still largely used in many developing countries. Previous studies have shown multiple adverse health effects of endosulfan. However, the neurotoxicity of endosulfan has not been fully elucidated. In this study, endosulfan isomers (α-/β-endosulfan) and their major metabolites (endosulfan sulfate, endosulfan diol, and endosulfan lactone) were, respectively, exposed to human neuroblastoma SH-SY5Y cells. Results showed that both α-endosulfan and β-endosulfan caused decrease of cell viability and morphological damages in a dose-dependent manner. Their median effective concentrations (EC50s) were respectively 79.6 μM (α-endosulfan) and 50.37 μM (β-endosulfan) for 72 h exposure. EC50s of α/β-endosulfan mixture were lower than that of the single isomer. However, EC50s of its metabolites were higher than that of technical endosulfan. Endosulfan and its metabolites caused increases of reactive oxygen species and the lipid peroxidation, but decrease of superoxide dismutase in a dose-dependent manner. These results indicate that α-endosulfan exhibits higher neurotoxicity than β-endosulfan. Mixture of endosulfan isomers shows stronger cytotoxicity than the single isomer. After endosulfan is degraded, cytotoxicity of its metabolites decreases gradually. The neurotoxicity of endosulfan and its metabolites is closely related to oxidative damage and antioxidative deficit.

Single nucleotide polymorphism in the microRNA-199a binding site of HIF1A gene is associated with pancreatic ductal adenocarcinoma risk and worse clinical outcomes

Hypoxia-inducible factor-1 alpha (HIF-1α) is over-expressed in many cancers including pancreatic ductal adenocarcinoma (PDAC) and correlated with poor prognosis. We aim to determine the effect of germline genetic variants on the regulation of the homeostasis of the miRNA-gene regulatory loop in HIF1A gene and PDAC risk. HIF1A rs2057482 single nucleotide polymorphism (SNP) was genotyped in 410 PDAC cases and 490 healthy controls. The CC genotype SNP HIF1A is significantly correlated with PDAC risk (OR = 1.719, 95% CI: 1.293-2.286) and shorter overall survival (OS, P<0.0001) compared with the CT/TT alleles group. The C/T variants of rs2057482, a SNP located near the miR-199a binding site in HIF1A, could lead to differential regulation of HIF1A by miR-199a. Specifically, the C allele of rs2057482 weakened miR-199a-induced repression of HIF-1α expression on both mRNA and protein levels. In the PDAC tissue, individuals with the rs2057482-CC genotype expressed significantly higher levels of HIF-1α protein than those with the rs2057482-CT/TT genotype (P<0.0001). Both the CC genotype of SNP HIF1A and increased HIF-1α expression are significantly associated with shorter OS of patients with PDAC. After adjusted by TNM staging, differentiation grade, and the levels of CA19-9, both SNP HIF1A and HIF-1α expression retained highly significance on OS (P<0.0001). Taken together, our study demonstrates that host genetic variants could disturb the regulation of the miR-199a/HIF1A regulatory loop and alter PDAC risk and poor prognosis. In conclusion, the rs2057482-CC genotype increases the susceptibility to PDAC and associated with cancer progression.

Soluble CD40 ligands sensitize the epithelial ovarian cancer cells to cisplatin treatment

OBJECTIVE

CD154 (CD40L) is a protein that is primarily expressed on activated T cells and is a member of the TNF superfamily of molecules. It binds to CD40 on antigen-presenting cells (APC), which leads to many effects depending on the target cell type. Being an activator of immune cells, CD40L has also been shown to directly induce apoptosis in tumor cells by multiple mechanisms. To understand the role of sCD40L in regulating the proliferation of epithelial ovarian cancer cells treated or untreated with cisplatin.

METHODS

Epithelial ovarian cancer cells: SKOV3 and its cisplatin-resistant strain SKOV3/DDP cells were used to test the effect of sCD40L and cisplatin. The proliferation of SKOV3 and SKOV3/DDP cells were measured by MTT. Cell cycle was assessed by flow cytometry. The mRNA expressions of targeted genes were detected by qRT-PCR. The protein expressions were detected by Western blotting.

RESULTS

sCD40L showed a significant dose-dependence inhibitory effect on the proliferation of ovarian cancer cell lines. sCD40L in combination with cisplatin could sensitized SKOV3/DDP cells to cisplatin treatment and reversed the drug resistance of SKOV3/DDP cells. The reversal ratios of 1 μg/ml sCD40L combined with cisplatin in SKOV3 and SKOV3/DDP cells were 2.11, 2.71, while the reversal ratios of 2 μg/ml sCD40L combined with cisplatin in SKOV3 and SKOV3/DDP cells were 3.78, 5.20, respectively. sCD40L or sCD40L combined cisplatin increased tumor cells in G0/G1 phase. sCD40L in combination with cisplatin decreased the expression levels of GST-π, LRP, Survivin, p53 and Bcl-2 in both epithelial ovarian cancer cell lines. The protein expression level of GST-π, LRP and P53 protein was also decreased upon sCD40L in combination with cisplatin although the expression level of Bcl-2 and survivin protein had no significant difference.

CONCLUSION

sCD40L inhibits the proliferation of SKOV3 and SKOV3/DDP cells. The combined application of sCD40L and cisplatin can strength the inhibitory effect of cisplatin, and to a certain extent, reversing the resistance to cisplatin in SKOV3/DDP cells. sCD40L could lead a cell block in G0/G1 phase and make the cell growth restrained. sCD40L could induce SKOV3 and SKOV3/DDP cells apoptosis and reverse drug resistance through cutting GST-π mRNA, LRP mRNA, survivin mRNA, p53 mRNA and Bcl-2 mRNA and decreasing the expression of GST-π, LRP and P53 protein in SKOV3 and SKOV3/DDP cells, which provides in-vivo experiment basis to the application of sCD40L as a drug improving ovarian cancer cells sensitivity to cisplatin.

Role of Bone Marrow-Derived Fibroblasts in Renal Fibrosis

Renal fibrosis represents a common pathway leading to progression of chronic kidney disease. Renal interstitial fibrosis is characterized by extensive fibroblast activation and excessive production and deposition of extracellular matrix (ECM), which leads to progressive loss of kidney function. There is no effective therapy available clinically to halt or even reverse renal fibrosis. Although activated fibroblasts/myofibroblasts are responsible for the excessive production and deposition of ECM, their origin remains controversial. Recent evidence suggests that bone marrow-derived fibroblast precursors contribute significantly to the pathogenesis of renal fibrosis. Understanding the molecular signaling mechanisms underlying the recruitment and activation of the bone marrow-derived fibroblast precursors will lead to novel therapy for the treatment of chronic kidney disease. In this review, we summarize recent advances in our understanding of the recruitment and activation of bone marrow-derived fibroblast precursors in the kidney and the development of renal fibrosis and highlights new insights that may lead to novel therapies to prevent or reverse the development of renal fibrosis.

Attenuation of the programmed cell death-1 pathway increases the M1 polarization of macrophages induced by zymosan

Programmed cell death-1 (PD-1) is a member of the CD28 superfamily that delivers negative signals on interaction with its 2 ligands, PD-L1 and PD-L2. We assessed the contribution of the PD-1 pathway to regulating the polarization of macrophages that promote inflammation induced by zymosan. We found that PD-1^−/− mice developed robust peritonitis with more abundant infiltration of M1 macrophages, accompanied by higher levels of pro-inflammation factors, especially monocyte chemotactic protein-1 (MCP-1) compared with wild-type controls ex vivo and in vitro. Our results indicated that PD-1 deficiency promotes M1 rather than M2 polarization of macrophages by enhancing the expression of p-STAT1/p-NF-κB p65 and downregulating p-STAT6. We found that PD-1 engagement followed by zymosan stimulation might primarily attenuate the phosphorylation of tyrosine residue in PD-1 receptor/ligand and the recruitment of SHP-2 to PD-1 receptor/ligand, leading to the reduction of M1 type cytokine production.

Arsenic induces apoptosis by the lysosomal-mitochondrial pathway in INS-1 cells

Recently, long term arsenic exposure was considered to be associated with an increased risk of diabetes mellitus. While a relation of cause-and-effect between apoptosis of pancreatic β-cells and arsenic exposure, the precise mechanisms of these events remains unclear. The aim of this study was to explore arsenic-induced pancreatic β-cell apoptosis and the mechanisms of through the possible link between lysosomal and the mitochondrial apoptotic pathway. After exposure to 10 μM of arsenic, the reactive oxygen species (ROS) level was significantly increased at 12 h, while the mitochondrial membrane potential was reduced at 24 h and the lysosomal membrane integrity was disrupted at 48 h. A significant increase in protein expression for cytochrome c was also observed using Western blot analysis after exposure to arsenic for 48 h. To further demonstrate that arsenic reduced the lysosomal membrane integrity, cells pretreated with NH4 Cl and exposed to arsenic harbored a lower fluorescence increase than cells that were only exposed to arsenic. In addition, apoptosis was mesured using Hoechst 33342/PI dual staining by microscopy and annexin V-FITC/propidium iodide dual staining by flow cytometry. The results show an increased uptake of the arsenic dose and the cells changed from dark blue to light blue, karyopyknosis, nuclear chromatin condensation, side set or fracture, and a correlation was found between the number of apoptotic cells and arsenic dose. The result of present study suggest that arsenic may induce pancreatic β-cell apoptosis through activation of the lysosome-mitochondrial pathway.

Dicliptera Chinensis polysaccharides target TGF-β/Smad pathway and inhibit stellate cells activation in rats with dimethylnitrosamine-induced hepatic fibrosis

This study aims to study impact of Dicliptera chinensis polysaccharide (DCP) on hepatic fibrosis (HF) and activation of hepatic stellate cells (HSCs). Liver fibrosis model was induced by intraperitoneal injection of dimethyl nitrosamines (DMN) in rat. Rats in treatment group were administrated with different concentrations of DCP (0, 100, 300 mg/kg) by intraperitoneal injection. Hematoxylin and eosin (H&E) and Masson's trichrome staining were used to assess histo-pathological change. α-SMA, TGF-β1 and pSmad 2/3 were assayed by immuno-histochemistry. HSC-T6 cells were stimulated by recombined rat TGF-β1 (1 ng/mL) to simulate an activating model in vitro and then interfered with DCP (concentration of 0, 25, 50, 100, 200, 400 µg/ml). MTT assay was used to determine cell proliferation and western blotting was used to detect α-SMA and pSmad 2/3 expression. Results demonstrated that DCP alleviated DMN-induced liver fibrosis in rat and significantly down-regulated TGF-β1 expression, pSmad2/3 and α-SMA in liver tissue in a dose-dependent way. DCP inhibited proliferation and activation of TGF-β1-stimulated HSC-T6 in vitro and significantly down-regulated α-SMA and pSmad2/3 expression. In conclusion, this study revealed that DCP attenuates progression of liver fibrosis through suppressing TGF-β/Smad pathway. DCP is a potential botanical polysaccharide to management liver fibrosis.

Targeting HDAC with a novel inhibitor effectively reverses paclitaxel resistance in non-small cell lung cancer via multiple mechanisms

Chemotherapy paclitaxel yields significant reductions in tumor burden in the majority of advanced non-small cell lung cancer (NSCLC) patients. However, acquired resistance limits its clinical use. Here we demonstrated that the histone deacetylase (HDAC) was activated in paclitaxel-resistant NSCLC cells, and its activation promoted proliferation and tumorigenesis of paclitaxel-resistant NSCLC cells in vitro and in vivo. By contrast, knockdown of HDAC1, a primary isoform of HDAC, sensitized resistant cells to paclitaxel in vitro. Furthermore, we observed that overexpression of HDAC1 was associated with the downregulation of p21, a known HDAC target, in advanced NSCLC patients with paclitaxel treatment, and predicted chemotherapy resistance and bad outcome. In addition, we also identified a novel HDACs inhibitor, SNOH-3, which inhibited HDAC expression and activity, induced cell apoptosis, and suppressed cell migration, invasion and angiogenesis. Notably, co-treatment with SNOH-3 and paclitaxel overcome paclitaxel resistance through inhibiting HDAC activity, leading to the induction of apoptosis and suppression of angiogenesis in vitro and in preclinical model. In summary, our data demonstrate a role of HDAC in paclitaxel-resistant NSCLC and provide a promising therapeutic strategy to overcome paclitaxel-acquired resistance.

Abnormal Amygdala Resting-State Functional Connectivity in Irritable Bowel Syndrome

BACKGROUND AND PURPOSE

Functional neuroimaging studies in irritable bowel syndrome have revealed abnormalities in the corticolimbic regions, specifically, hyperactivity of the amygdala during visceral and somatic stimulation. This study investigated changes in the neural circuitry of the amygdala in patients with irritable bowel syndrome based on resting-state functional connectivity.

MATERIALS AND METHODS

Functional MR imaging data were acquired from 31 patients with irritable bowel syndrome and 32 healthy controls (matched for age, sex, and educational level) during rest, and the resting-state functional connectivity of bilateral amygdalae was compared. Multiple regression was performed to investigate the relationship between clinical indices of patients with irritable bowel syndrome and resting-state functional connectivity.

RESULTS

Compared with healthy controls, patients with irritable bowel syndrome had higher positive resting-state functional connectivity between the amygdala and insula, midbrain, parahippocampal gyrus, pre- and postcentral gyri, and supplementary motor area. The inclusion of anxiety and depression as covariates did not alter amygdala resting-state functional connectivity differences between the study groups. Multiple covariate regression results showed that the pain intensity in patients with irritable bowel syndrome positively correlated with resting-state functional connectivity between the amygdala and supplementary motor area, pre- and postcentral gyri, and insula, while the Irritable Bowel Syndrome-Symptom Severity Score positively correlated with resting-state functional connectivity between the amygdala and insula and midbrain.

CONCLUSIONS

Patients with irritable bowel syndrome showed disturbed amygdala resting-state functional connectivity with the corticolimbic regions, which could partly account for the enhanced emotional arousal and visceral information processing associated with irritable bowel syndrome.

Incidence, Risk Factors, and the Protective Effect of High Body Mass Index against Sarcopenia in Suburb-Dwelling Elderly Chinese Populations

BACKGROUND

Few studies have explored the risk factors of sarcopenia in certain cohorts. The objective of this study was to examine the incidence of sarcopenia and associated factors over a 1-year period in an elderly Chinese suburban population.

METHODS

This study was conducted on 356 Chinese suburb-dwelling participants aged ≥60 years, for whom detailed information regarding sociodemographics, behavioral characteristics, and medical conditions had been documented. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) criteria. Sarcopenia incidence was documented after one year of follow-up, and correlated with several possible factors.

RESULTS

At baseline, 64 (9.7%) of the initial 657 participants had sarcopenia. The prevalence of sarcopenia was 10.4% after one year. Between baseline and 1-year follow-up, 13 of the participants without sarcopenia at baseline had developed sarcopenia. After multivariate adjustments, it was found that the incidence of sarcopenia increased with age and high body mass index (BMI) is associated with less incidence of sarcopenia. Incidence was also higher among women.

CONCLUSIONS

We found sarcopenia incidence increased with age, and women were more likely to have sarcopenia. A higher BMI is also associated with a lower incidence of sarcopenia. Maintaining a healthy weight could be beneficial in the prevention of sarcopenia.