miR-375 is upregulated in acquired paclitaxel resistance in cervical cancer

Background:

Chemo-resistance is one of the key causal factors in cancer death and emerging evidences suggest that microRNAs (miRNAs) have critical roles in the regulation of chemo-sensitivity in cancers. Cervical cancer is one of the most common malignancies in women and insensitive to chemotherapy clinically.

Methods:

The differentially expressed miRNAs in cervical squamous cell carcinoma tissues were screened by using a microarray platform (μParaflo Sanger miRBase release 13.0). The expression of miR-375 was determined by stem-loop RT–PCR using 23 clinical cervical cancer samples and 2 cervical cancer cell lines. We exogenously upregulated miR-375 expression in SiHa and Caski cells using a pre-miRNA lentiviral vector transfection and observed its impact on paclitaxel sensitivity using MTS. The cells that stably overexpressed miR-375 were subcutaneously injected into mice to determine tumour growth and chemo-sensitivity in vivo.

Results:

Twenty-one differentially expressed miRNAs were found by miRNA microarray between pro- and post-paclitaxel cervical cancer tissues. Of those, miR-375 showed consistent high expression levels across paclitaxel-treated cervical cells and tissues. Paclitaxel induced upregulated miR-375 expression in a clear dose-dependent manner. Forced overexpression of miR-375 in cervical cancer cells decreased paclitaxel sensitivity in vitro and in vivo.

Conclusion:

Collectively, our results suggest that miR-375 might be a therapeutic target in paclitaxel-resistant cervical cancer.

Blood glucose fluctuation affects skin collagen metabolism in the diabetic mouse by inhibiting the mitogen-activated protein kinase and Smad pathways

BACKGROUND

We recently reported that in mice, blood glucose fluctuations (BGF) produced more detrimental effects on skin structure and function than did diabetes alone.

AIM

To determine whether treatment of BGF changes the collagen metabolism in the skin of diabetic mice, and to explore its possible molecular mechanism further.

METHODS

The study used diabetic and BGF animal models. Immunohistochemistry, western blotting and real-time PCR analysis were used to detect the expression of type I collagen, matrix metalloproteinase (MMP)-1, MMP-2 and MMP-13, tissue inhibitor of metalloproteinase (TIMP)-1, extracellular signal-regulated kinase, p38, and Smad2/3. The activities of mitogen-activated protein kinase (MAPK) and Smad signal molecules were also detected by western blotting, and the skin fibroblast ultrastructure was examined using an electron microscope.

RESULTS

BGF treatment produced a twofold reduction in type I collagen synthesis compared with diabetes-only mice. Expression of MMP-1, MMP-2 and MMP-13 increased markedly in the BGF-treated mice, but TIMP-1 expression was strongly downregulated by the BGF treatment. There was also evidence of higher levels of apoptosis of skin fibroblasts after BGF treatment.

CONCLUSIONS

BGF treatment can affect collagen production in the skin of diabetic BGF mice by inhibiting collagen synthesis and increasing collagen degradation. Furthermore, both MAPK and Smad signalling pathways seem to play a role in the inhibition of collagen production in diabetic mice treated with BGF.

Disruption of cellulose synthesis by 2,6-dichlorobenzonitrile affects the structure of the cytoskeleton and cell wall construction in Arabidopsis

Cellulose is the major component of plant cell walls and is an important source of industrial raw material. Although cellulose biosynthesis is one of the most important biochemical processes in plant biology, the regulatory mechanisms of cellulose synthesis are still unclear. Here, we report that 2,6-dichlorobenzonitrile (DCB), an inhibitor of cellulose synthesis, inhibits Arabidopsis root development in a dose- and time-dependent manner. When treated with DCB, the plant cell wall showed altered cellulose distribution and intensity, as shown by calcofluor white and S4B staining. Moreover, pectin deposition was reduced in the presence of DCB when immunostained with the monoclonal antibody JIM5, which was raised against pectin epitopes. This result was confirmed using Fourier transform infrared (FTIR) analysis. Confocal microscopy revealed that the organisation of the microtubule cytoskeleton was significantly disrupted in the presence of low concentrations of DCB, whereas the actin cytoskeleton only showed changes with the application of high DCB concentrations. In addition, the subcellular dynamics of Golgi bodies labelled with N-ST-YFP and TGN labelled with VHA-a1-GFP were both partially blocked by DCB. Transmission electron microscopy indicated that the cell wall structure was affected by DCB, as were the Golgi bodies. Scanning electron microscopy showed changes in the organisation of cellulose microfibrils. These results suggest that the inhibition of cellulose synthesis by DCB not only induced changes in the chemical composition of the root cell wall and cytoskeleton structure, but also changed the distribution of cellulose microfibrils, implying that cellulose plays an important role in root development in Arabidopsis.

Temperature and boundary influence on cement hydration monitoring using embedded piezoelectric transducers

In this study, the hydration process was monitored using embedded ultrasonic transducers. It was found that the ultrasonic amplitude decreased and fluctuated at the very early age, several hours after the beginning of fast hydration. The embedded transducers are very different from the surface coupled ones for they were directly influenced by the cement paste, such as the varying temperature and the boundary condition. Experiments were carried out to find out which factor result in such decrease and fluctuation. Test results showed that both the temperature and boundary conditions affect the ultrasonic measurement. When the hydration progressed under constant temperature, the amplitude of the ultrasonic wave decreased smoothly during certain period. When the hardened specimen was tested, it was found that the amplitude would decrease obviously with the increasing of temperature and vice versa. The findings could be used to interpret the amplitude plot obtained in the normal hydration monitoring using embedded transducers.

Inactivation of bacteriophages by high levels of dissolved CO2

We developed a system with high levels of dissolved CO2 for water disinfection. Bacteriophages MS2, Qbeta and phiX174 were selected as the inactivation targets. A relatively mild inactivation effect was observed on MS2 and Qbeta at different initial concentrations of dissolved CO2 at 0.3 MPa in 20-30 min. When the pressure was increased to 0.6 MPa, the inactivation of MS2 and Qbeta was differentially improved. However, this system was less effective for the inactivation of phiX174. The capsid surface property is a probable reason for the low inactivation of phiX174. The pH was not a key factor in the inactivation of bacteriophages; moreover, the results obtained using alternative gases (pressurized air and O2) indicated that only CO2 inactivated these bacteriophages. A comparison between the results of real time polymerase chain reaction (RT-PCR) and plaque assay showed that some RNA moved out from the capsid after treatment. Capsid damage by CO2 expansion was the likely mechanism of inactivation with our method.

Cell-cycle arrest at G2/M and proliferation inhibition by adenovirus-expressed mitofusin-2 gene in human colorectal cancer cell lines

The mitofusin-2 (Mfn2) is a novel gene characterised as a cell proliferation inhibitor. Mfn2 protein over-expression, mediated by an adenovirus, has a significant anti-proliferative effect in hepatoma carcinoma cells. However, there is no report on the effect of Mfn2 on colorectal cancer (CRC). In this study, we found that Mfn2 protein and mRNA levels were downregulated in CRC tissues compared to nearby normal tissues. An adenovirus encoding the complete Mfn2 open reading frame (Ad-Mfn2) exhibited a prominent anti-proliferative effect in the CRC cell lines HCT 116, HT-29, and SW480. Ad-Mfn2 infection significantly inhibited the proliferation of CRC cells compared with Ad-GFP infection. Mfn2 overexpression resulted in a cell-cycle arrest at G2/M phase in CRC cells, and it increased the levels of p-cdc2 (Tyr15) and Myt1; however, the levels of cyclin B1 and p-ERK1/2 was reduced. Mfn2 overexpression aslo increased the levels of active caspase-3 and cleaved PARP. Taken together, these findings indicate that Mfn2 has a significant anti-proliferative effect in CRC cells using adenoviral vectors.

Pathways of phosphate uptake from aqueous solution by ZnAl layered double hydroxides

ZnAl layered double hydroxides (LDHs) were prepared by urea hydrolysis-based coprecipitation for removing phosphate from aqueous solutions. The chemical formula of the product was determined as Zn5.54Al3.02(OH)8.73(CO3)0.57Cl5.66·7.84H2O. Chloride ion was the major interlayer anion of the ZnAl LDHs. Adsorption of phosphate onto the ZnAl sorbent over the entire study period was not in close agreement with pseudo-first-order or pseudo-second-order models. The adsorption can be divided into two steps. A fast adsorption was observed during the first 10 h with a marked increase in the concentration of Cl(-) in the bulk solution. This indicated that the adsorption of phosphate was largely attributed to the ion exchange between phosphate and the interlayer Cl(-). A second fast adsorption of phosphate occurred after 10 h. During this period, the pH increased slowly, whereas the Cl(-) concentration was stable. The uptake of phosphate was likely attributed to OH(-)-H2PO4(-)/HPO4(2-) ion exchange as well as surface adsorption/complexation. Acidic conditions favored adsorption of phosphate by ZnAl LDHs, which is consistent with the pH increases during the adsorption. Coexisting anions, e.g., SO4(2-) and CO3(2-), are competitive ions for the adsorption of phosphate. The results verify the contribution of ion exchange and surface adsorption/complexation in the removal of phosphate by ZnAl LDHs.

Preparation and characterization of β-lactoglobulin hydrolysate-iron complexes

The purpose of this study was to determine the best preparation condition of β-lactoglobulin hydrolysate-iron complexes and characterize its structural transformation both before and after binding using the UV-visible absorption spectrum, Fluorescence spectrum, and Fourier transform infrared spectroscopy. Results showed that β-lactoglobulin hydrolysates obtained with alcalase after hydrolysis for 6h possessed the highest iron-binding capacity. The highest yield of complexes was obtained when the mass ratio between β-lactoglobulin hydrolysate and Fe(3+) reached 40:1, with the optimal pH value of 7.0. All of the spectra indicated that some sites such as amido bonds transformed during chelation, and nitrogen atoms could chelate with Fe(3+) to form coordinate bonds by offering electron pairs. Therefore, β-lactoglobulin hydrolysate-iron complexes may be good carriers for iron and possess great potential to be used as iron supplements.

Cysteinyl cathepsins: multifunctional enzymes in cardiovascular disease

Until recently, the role of lysosomal cysteine protease cathepsins in intracellular protein degradation was believed to be mainly restricted to scavenging. However, recent studies have revealed nontraditional roles for cysteine protease cathepsins in the extracellular space during the development and progression of cardiovascular disease. Although the precise mechanisms are unknown, data from animal studies suggest that members of the cathepsin family, like other extracellular proteases, contribute to extracellular matrix protein remodeling and interstitial matrix degradation, as well as to cell signaling and cell apoptosis in heart disease. Inflammatory cytokines and hormones regulate the expression and secretion of cathepsins in cultured cardiovascular cells and macrophages. Serum levels of cathepsins L, S, and K and their endogenous inhibitor cystatin C may be useful predictive biomarkers in patients with coronary artery disease and cardiac disease. Furthermore, in vivo pharmacological intervention with a synthetic cathepsin inhibitor and cardiovascular drugs (including statins and angiotensin II type 1 receptor antagonists) has the potential for pharmacologic targeting of cathepsins in cardiovascular disease. This review focuses on cathepsin biology (structure, synthesis, processing, activation, secretion, activity regulation, and function) and the involvement of cysteinyl cathepsins in the pathogenesis of several heart and vessel diseases, especially with respect to their potential application as diagnostic and prognostic markers and drug targets to prevent inappropriate proteolysis in cardiovascular disease.

Alternative immunomodulatory strategies for xenotransplantation: CD40/154 pathway-sparing regimens promote xenograft survival

Immunosuppressive therapies that block the CD40/CD154 costimulatory pathway have proven to be uniquely effective in preclinical xenotransplant models. Given the challenges facing clinical translation of CD40/CD154 pathway blockade, we examined the efficacy and tolerability of CD40/CD154 pathway-sparing immunomodulatory strategies in a pig-to-nonhuman primate islet xenotransplant model. Rhesus macaques were rendered diabetic with streptozocin and given an intraportal infusion of ≈ 50 000 islet equivalents/kg wild-type neonatal porcine islets. Base immunosuppression for all recipients included maintenance therapy with belatacept and mycophenolate mofetil plus induction with basiliximab and LFA-1 blockade. Cohort 1 recipients (n = 3) were treated with the base regimen alone; cohort 2 recipients (n = 5) were additionally treated with tacrolimus induction and cohort 3 recipients (n = 5) were treated with alefacept in place of basiliximab, and more intense LFA-1 blockade. Three of five recipients in both cohorts 2 and 3 achieved sustained insulin-independent normoglycemia (median rejection-free survivals 60 and 111 days, respectively), compared to zero of three recipients in cohort 1. These data show that CD40/CD154 pathway-sparing regimens can promote xenoislet survival. Further optimization of these strategies is warranted to aid the clinical translation of islet xenotransplantation.

Contribution of lysosomal cysteine proteases in cardiac and renal diseases

Cardiac and renal diseases (CRDs) are characterized by extensive remodeling of the extracellular matrix (ECM) architecture of the cardiorenal system. Among the many extracellular proteolytic enzymes present in cardiorenal cells and involved in ECM remodeling, members of the matrix metalloproteinase family and serine protease family have received the most attention. However, recent findings from laboratory and clinical studies have indicated that cysteine protease cathepsins also participate in pathogenesis of the heart and kidney. Deficiency and pharmacological inhibition of cathepsins have allowed their in vivo evaluation in the setting of pathological conditions. Furthermore, recent studies evaluating the feasibility of cathepsins as a diagnostic tool have suggested that the serum levels of cathepsins L, S and K and their endogenous inhibitor cystatin C have predictive value as biomarkers in patients with coronary artery disease and heart and renal failure. The goal of this review is to highlight recent discoveries regarding the contributions of cathepsins in CRDs, particularly hypertensive heart failure and proteinuric kidney disease.