CBLC inhibits the proliferation and metastasis of breast cancer cells via ubiquitination and degradation of CTTN.

The E3 ubiquitin ligase is an important regulator of cell signaling and proteostasis and is tightly controlled in many diseases, including cancer. Our study aimed to investigate the biological role of the E3 ubiquitin ligase CBLC in breast cancer and elucidate the specific mechanistic network underlying CBLC-mediated target substrate degradation, cell proliferation and metastasis. Here, we showed that CBLC expression was higher in breast cancer tissues and cells than that in normal tissues and cells. Higher expression of CBLC predicted a better prognosis for breast cancer patients. CBLC inhibited the proliferation, migration and invasion of breast cancer cells. Co-IP and immunofluorescence co-localization assays demonstrated that CBLC interacted with CTTN in the cytoplasm. CBLC promoted the degradation of CTTN through the ubiquitin-proteasome pathway without affecting its mRNA level. The inhibitory effect of CBLC on breast cancer cell proliferation, migration and invasion could partly be reversed by CTTN. Taken together, our study clarified the biological role of CBLC as a tumor suppressor and discovered its functional substrate, providing a molecular basis for CBLC/CTTN as a potential therapeutic target in breast cancer.

[Injury of L-02 hepatocytes induced by NaAsO2 is related to down-regulated expression of p14ARF and increased expression of MDM2 and p53].

Objective To investigate the effects of sodium arsenite (NaAsO2) on p14 alternative reading frame (p14ARF), murine double minute 2 (MDM2) and p53 expressions in L-02 hepatocytes. Methods L-02 hepatocytes were cultured in medium containing (0, 5, 10, 15, 20, 25) µmol/L NaAsO2 for 48 hours. The cell morphology was evaluated by phase-contrast microscopy and cell proliferation was detected by CCK-8 assay. The apoptosis of hepatocytes was detected by annexin V/propidium iodide (annexin V-FITC/PI) double staining followed by flow cytometry. The mRNA and protein expressions of p14ARF, MDM2 and p53 were detected by real-time fluorescence quantitative PCR and Western blotting. Results Compared with the control group, the proliferation activity of L-02 hepatocytes decreased and the apoptotic rate of L-02 hepatocytes increased significantly. With the increase of NaAsO2 concentration, p14ARF mRNA and protein levels decreased gradually, while MDM2 mRNA and protein levels increased gradually. There was no significant difference in the expression of p53 mRNA, but the relative expression level of p53 protein increased gradually. Conclusion The injury of L-02 hepatocytes induced by NaAsO2 may be related to the down-regulation of p14ARF expression and the up-regulation of p53 and MDM2 expression.

Electrochemical Biosensor for DNA Methylation Detection through Hybridization Chain-Amplified Reaction Coupled with a Tetrahedral DNA Nanostructure.

DNA methylation is a key factor in the pathogenesis of gene expression diseases or malignancies. Thus, it has become a significant biomarker for the diagnosis and prognosis of these diseases. In this paper, we designed an ultrasensitive and specific electrochemical biosensor for DNA methylation detection. The platform consisted of stem-loop-tetrahedron composite DNA probes anchoring at a Au nanoparticle-coated gold electrode, a restriction enzyme digestion of HpaII, and signal amplification procedures including electrodeposition of Au nanoparticles, hybridization chain reaction, and horseradish peroxidase enzymatic catalysis. Under optimal conditions, the design showed a broad dynamic range from 1 aM to 1 pM and a detection limit of about 0.93 aM. The approach also showed ideal specificity, repeatability, and stability. The recovery test demonstrated that the design is a promising platform for DNA methylation detection under clinical circumstances and could meet the need for cancer diagnosis.

Quercetin from Polygonum capitatum Protects against Gastric Inflammation and Apoptosis Associated with Helicobacter pylori Infection by Affecting the Levels of p38MAPK, BCL-2 and BAX.

Helicobacter pylori-associated gastritis is a major threat to public health and Polygonum capitatum (PC) may have beneficial effects on the disease. However, the molecular mechanism remains unknown. Quercetin was isolated from PC and found to be a main bioactive compound. The effects of quercetin on human gastric cancer cells GES-1 were determined by xCELLigence. H. pylori-infected mouse models were established. All mice were divided into three groups: control (CG, healthy mice), model (MG, H. pylori infection) and quercetin (QG, mouse model treated by quercetin) groups. IL-8 (interleukin-8) levels were detected via enzyme-linked immunosorbent assay (ELISA). Cell cycle and apoptosis were measured by flow cytometry (FCM). Quantitative reverse transcription PCR (qRT-PCR) and Western Blot were used to detect the levels of p38MAPK (38-kD tyrosine phosphorylated protein kinase), apoptosis regulator BCL-2-associated protein X (BAX) and B cell lymphoma gene 2 (BCL-2). The levels of IL-8 were increased by 8.1-fold in a MG group and 4.3-fold in a QG group when compared with a CG group. In a MG group, G0-G1(phases of the cell cycle)% ratio was higher than a CG group while S phase fraction was lower in a model group than in a control group (p < 0.01). After quercetin treatment, G0-G1% ratio was lower in a QG group than a MG group while S phase fraction was higher than a MG group (p < 0.01). Quercetin treatment reduced the levels of p38MAPK and BAX, and increased the levels of BCL-2 when compared with a MG group (p < 0.05). Quercetin regulates the balance of gastric cell proliferation and apoptosis to protect against gastritis. Quercetin protects against gastric inflammation and apoptosis associated with H. pylori infection by affecting the levels of p38MAPK, BCL-2 and BAX.

Flavonoid Glycosides of Polygonum capitatum Protect against Inflammation Associated with Helicobacter pylori Infection.

The antibacterial and anti-inflammatory activities, and protective effects of extracts (flavonoid glycosides) of Polygonum capitatum were investigated to detect the evidence for the utilization of the herb in the clinical therapy of gastritis caused by H. pylori. A mouse gastritis model was established using H. pylori. According to treating methods, model mice were random assigned into a model group (MG group), a triple antibiotics group (TG group, clarithromycin, omeprazole and amoxicillin), low/middle/high concentrations of flavonoid glycosides groups (LF, MF and HF groups) and low/middle/high concentrations of flavonoid glycosides and amoxicillin groups (LFA, MFA and HFA groups). A group with pathogen-free mice was regarded as a control group (CG group). The eradicate rates of H. pylori were 100%, 93%, 89% in TG, MFA and HF groups. The serum levels of IFN-gamma and gastrin were higher in a MG group than those from all other groups (P < 0.05). The serum levels of IFN-gamma and gastrin were reduced significantly in LF, MF and HF groups (P < 0.05) while little changes were observed in LFA, MFA and HFA groups. In contrast, the serum levels of IL-4 were lower and higher in MG and CG groups compared with other groups (P<0.05). The serum levels of IL-4 were increased significantly in LF, MF and HF groups (P < 0.05) while little changes were found in LFA, MFA and HFA groups. According to pathological scores, flavonoid glycosides therapy showed better protection for gastric injuries than the combination of flavonoid glycoside and amoxicillin (P < 0.05). The results suggested that flavonoid glycoside has repairing functions for gastric injuries. The results suggest that the plant can treat gastritis and protect against gastric injuries. The flavonoid glycosides from Polygonum capitatum should be developed as a potential drug for the therapy of gastritis caused by H. pylori.