Development of a new ferulic acid certified reference material for use in clinical chemistry and pharmaceutical analysis

This study compares the results of three certified methods, namely differential scanning calorimetry (DSC), the mass balance (MB) method and coulometric titrimetry (CT), in the purity assessment of ferulic acid certified reference material (CRM). Purity and expanded uncertainty as determined by the three methods were respectively 99.81%, 0.16%; 99.79%, 0.16%; and 99.81%, 0.26% with, in all cases, a coverage factor (k) of 2 (P=95%). The purity results are consistent indicating that the combination of DSC, the MB method and CT provides a confident assessment of the purity of suitable CRMs like ferulic acid.Abbreviations: ASTM, American Society for Testing and Materials; CRM, certified reference material; CT, coulometric titrimetry; DAD, diode-array detector; DSC, differential scanning calorimetry; EDQM, European Directorate for Quality Medicine; GUM, Guide to the Expression of Uncertainty in Measurement; ISO, International Organization for Standardization; MB, mass balance; RM, reference material; SI, International System of Units; WHO, World Health OrganizationKEY WORDS: Differential scanning  calorimetry, Mass balance, Coulometric titrimetry, Certified reference  material, Uncertainty, Ferulic acid     

Cell membrane gp96 facilitates HER2 dimerization and serves as a novel target in breast cancer

HER2 receptor dimerization is a critical step in the HER2 activation process. Here, we demonstrated that heat shock protein gp96 on cell membrane interacts with HER2, facilitates HER2 dimerization and promotes cell proliferation. Cell membrane gp96 levels were observed to correlate with HER2 phosphorylation in primary breast tumors. Finally, we provide evidence that targeting gp96 with a specific monoclonal antibody led to decreased cell growth and increased apoptosis in vitro, and suppression of tumor growth in vivo. Our work represents a new therapeutic strategy for inhibiting HER2 signaling in cancer.     

E2F7 overexpression leads to tamoxifen resistance in breast cancer cells by competing with E2F1 at miR-15a/16 promoter

About 50–70% of breast cancers are estrogen receptor α (ERα) positive and most of them are sensitive to endocrine therapy including tamoxifen. However, one third of these patients will eventually develop resistance and relapse. We found that the expression of miR-15a and miR-16 were significantly decreased in tamoxifen resistant ER positive breast cancer cell lines. Exogenous expression of miR-15a/16 mimics re-sensitized resistant cells to tamoxifen by inhibiting Cyclin E1 and B cell lymphoma-2 (Bcl-2) to induce cell growth arrest and apoptosis respectively. Further, we identified that a repressive member of E2F family, E2F7, was responsible for the suppression of miR-15a/16 cluster by competing with E2F1 for E2F binding site at the promoter of their host gene DLEU2. Moreover, high expression of E2F7 is correlated with high risk of relapse and poor prognosis in breast cancer patients receiving tamoxifen treatment. Together, our results suggest that overexpression of E2F7 represses miR-15a/16 and then increases Cyclin E1 and Bcl-2 that result in tamoxifen resistance. E2F7 may be a valuable prognostic marker and a therapeutic target of tamoxifen resistance in breast cancer.     

Hepatitis B virus core antigen as a carrier for Chlamydia trachomatis MOMP multi-epitope peptide enhances protection against genital chlamydial infection

Chlamydia trachomatis (Ct) is the leading cause of sexually transmitted diseases worldwide. There is no safe and effective vaccine to control the spread of Ct. In development of Ct vaccine, selection of appropriate candidate antigens and an effective delivery system may be the main challenges. Multi-epitope of major outer membrane protein (MOMPm) is the most suitable candidate for a Ct vaccine, while hepatitis B virus core antigen (HBcAg) has unique advantages as vaccine delivery system. Therefore, in this study, we evaluated the immunogenicity and protective immune response of a novel candidate vaccine in a murine model of chlamydial genital infection. This candidate vaccine comprises MOMPm peptide delivered with HBcAg. Our results of Ct-specific serum IgG and secretory IgA assay, cytokine assay, and cytotoxic T-lymphocyte assay revealed that immunogenicity of the candidate vaccine was much better than that of the corresponding synthetic MOMPm peptide. Furthermore, the protective effect of the candidate vaccine was also shown much better than that of the synthetic peptide by calculating the isolation of Chlamydia from vaginal swabs and histopathological analysis. Taken together, our results indicate that HBcAg carrying Ct MOMPm could be an effective immune prophylactic for chlamydial infection.     

Down regulation of MiR-93 contributes to endometriosis through targeting MMP3 and VEGFA

Objective: This study aimed to explore the role of miRNAs in pathogenesis of endometriosis. Methodology: Endometrial samples from 57 females with endometriosis and 44 non-endometriotic controls were compared for the expression of a selected group of miRNAs. The regulatory function on downstream target was also explored. Results: The expression of miR-93 and miR106a was significantly reduced in endometriotic samples compared to that in non-endometriotic samples. High levels of MMP3 and VEGFA were detected in more than 50% ectopic endometrium tissues. A negative association was found between the expression of miR-93 and the protein levels of MMP3 (Pearson correlation, r=-0.39, P=0.0025) or VEGFA (Pearson correlation, r=-0.37, P=0.0047) in samples from endometriosis patients. Mechanistically, miR-93 targeted MMP3 and VEGFA by directly binding to the 3’UTR of MMP3 and VEGFA mRNAs, and thereby inhibited the proliferation, migration and invasive capability of endometrial stromal cells (ESCs). Conclusion: The finding of this study suggests that deregulation of miR-93 contribute to endometriosis by up-regulation of MMP3 and VEGFA and thus provide potential therapeutic targets for the treatment of endometriosis.     

Identification of a novel VNTR polymorphism in C6orf37 and its association with colorectal cancer risk in Chinese population

BACKGROUND: C6orf37 was a gene up-regulated in colorectal adenoma in our previous study. A variable region of C6orf37 sequence was found when we blasted its full sequence with NCBI nucleotide database. METHODS: RT-PCR and sequencing were conducted to identify the variable region of C6orf37 as VNTR. DHPLC was applied to detect the VNTR genotypes in 122 colorectal carcinoma patients and 166 healthy controls. RESULTS: A novel VNTR sequence found in C6orf37 second exon was composed of 15 base pair consensus sequence encoding 5-amino-acid (G-G-D-F-G). The repeat timePOST alleles contain three repeats (a), 4 repeats (b) and 5 repeats (c), respectively, which produced 3 homozygotes (a/a, b/b and c/c) and 3 heterozygotes (a/b, a/c and b/c). a, b, c allele frequencies were 0.145, 0.304, 0.551, respectively in Chinese population. Heterozygosity (H) was 0.583. Polymorphism information content (PIC) was 0.510. The distribution of genotypes and allele frequencies of the VNTR reached no significant difference between patients and healthy controls and there was no correlation between VNTR polymorphism and colorectal cancer clincopathological features. CONCLUSION: A novel VNTR polymorphism in C6orf37 exists in Chinese population and is not associated with colorectal cancer risk.     

Role of the PTEN signaling pathway in autism spectrum disorder

Autism is an etiologically heterogeneous group of neurodevelopmental disorders,diagnosed mostly by the clinical behavioral phenotypes.The concept that the tumor-related gene PTEN plays a critical role in autism spectrum disorder has emerged over the last decade.In this review,we focus on the essential role of the PTEN signaling pathway in neuronal differentiation and the formation of neural circuitry,as well as genetic mouse models with Pten manipulations.Particularly,accumulated data suggest that the effect of PTEN on neural stem-cell development contributes significantly to the pathophysiology of autism spectrum disorders.