[A protective effect conferred by KIR3DL1 and its cognate ligand against cervical cancer among ethnic Han Chinese population and its potential mechanism].

OBJECTIVE: To explore the role of inhibitory KIR (iKIR) and its cognate HLA ligand in the occurrence and development of cervical cancer among ethnic Han Chinese and its potential mechanism. METHODS: Peripheral blood samples from 265 Han Chinese patients with cervical intraepithelial neoplasia (CIN)/cervical cancer and 200 ethnically matched healthy controls were collected. The results of KIR PCR-SSP, HLA PCR-rSSO and KIR3DL1 PCR-SBT, together with cervical cancer data from the TCGA database, were used to assess the association of iKIR genes, receptor-ligand gene combinations, iKIR transcription level in the tumor tissue and the KIR3DL1 alleles with the occurrence and development of cervical cancer. RESULTS: Among the four iKIR genes (KIR2DL1, 2DL2/3, 3DL1 and 3DL2), the frequencies of KIR3DL1 and KIR3DL1-HLA-Bw4 genes among controls were significantly higher than those of the cervical cancer group (96.5% vs. 87.0%, P = 0.018; 81.5% vs. 64.8%, P=0.009). The survival rate of cervical cancer patients with a high transcription level of KIR3DL1 in tumor tissues was significantly higher than those with a low/medium transcription level (P=0.028). The frequency of strong-inhibitory and high-expression KIR3DL1*01502 allele among the healthy population was significantly higher than that of the cervical cancer group (76.0% vs. 59.3%, P =0.015). CONCLUSION: Combined KIR3DL1 and KIR3DL1-HLA-Bw4 can confer a protective effect against the development of cervical cancer, which may be attributed to the strong-inhibitory and high-expression allele of KIR3DL1*01502.

p.E95K mutation in Indian hedgehog causing brachydactyly type A1 impairs IHH/Gli1 downstream transcriptional regulation.

BACKGROUND: Brachydactyly type A1 (BDA1, OMIM 112500) is a rare inherited malformation characterized primarily by shortness or absence of middle bones of fingers and toes. It is the first recorded disorder of the autosomal dominant Mendelian trait. Indian hedgehog (IHH) gene is closely associated with BDA1, which was firstly mapped and identified in Chinese families in 2000. Previous studies have demonstrated that BDA1-related mutant IHH proteins affected interactions with its receptors and impaired IHH signaling. However, how the altered signaling pathway affects downstream transcriptional regulation remains unclear. RESULTS: Based on the mouse C3H10T1/2 cell model for IHH signaling activation, two recombinant human IHH-N proteins, including a wild type protein (WT, amino acid residues 28-202) and a mutant protein (MT, p.E95k), were analyzed. We identified 347, 47 and 4 Gli1 binding sites in the corresponding WT, MT and control group by chromatin immunoprecipitation and the overlapping of these three sets was poor. The putative cis regulated genes in WT group were enriched in sensory perception and G-protein coupled receptor-signaling pathway. On the other hand, putative cis regulated genes were enriched in Runx2-related pathways in MT group. Differentially expressed genes in WT and MT groups indicated that the alteration of mutant IHH signaling involved cell-cell signaling and cellular migration. Cellular assay of migration and proliferation validated that the mutant IHH signaling impaired these two cellular functions. CONCLUSIONS: In this study, we performed integrated genome-wide analyses to characterize differences of IHH/Gli1 downstream regulation between wild type IHH signaling and the E95K mutant signaling. Based on the cell model, our results demonstrated that the E95K mutant signaling altered Gli1-DNA binding pattern, impaired downstream gene expressions, and leaded to weakened cellular proliferation and migration. This study may help to deepen the understanding of pathogenesis of BDA1 and the role of IHH signaling in chondrogenesis.

Co-amplification at lower denaturation temperature-PCR: methodology and applications.

Co-amplification at lower denaturation temperature-polymerase chain reaction (COLD-PCR) is a novel form of PCR that selectively denatures and amplifies low-abundance mutations from mixtures of wild-type and mutation-containing sequences, enriching the mutation 10 to 100 folds. Due to the slightly altered melting temperature (Tm) of the double-stranded DNA and the formation of the mutation/wild-type heteroduplex DNA, COLD-PCR methods are sensitive, specific, accurate, cost-effective and easy to maneuver, and can enrich mutations of any type and at any position, even unknown mutations within amplicons. COLD-PCR and its improved methods are now applied in cancer, microorganisms, prenatal screening, animals and plants. They are extremely useful for early diagnosis, monitoring the prognosis of disease and the efficiency of the treatment, drug selection, prediction of prognosis, plant breeding and etc. In this review, we introduce the principles, key techniques, derived methods and applications of COLD-PCR.

A novel loss-of-function heterozygous BRCA2 c.8946_8947delAG mutation found in a Chinese woman with family history of breast cancer.

INTRODUCTION: Breast cancer is the most frequent female malignancy worldwide. Among them, some cases have hereditary susceptibility in two leading genes, BRCA1 and BRCA2. Heterozygous germ line mutations in them are related with increased risk of breast, ovarian and other cancer, following autosomal dominant inheritance mode. METHODS AND RESULTS: For purpose of early finding, early diagnosis and early treatment, mutation detecting of BRCA1/2 genes was performed in unselected 300 breast or ovarian patients and unaffected women using next-generation sequencing and then confirmed by Sanger sequencing. A non-previously reported heterozygous mutation c.8946_8947delAG (p.D2983FfsX34) of BRCA2 gene was identified in an unaffected Chinese woman with family history of breast cancer (her breast cancer mother, also carrying this mutation). The BRCA2-truncated protein resulted from the frame shift mutation was found to lose two putative nuclear localization signals and a Rad51-binding motif in the extreme C-terminal region by bioinformatic prediction. And then in vitro experiments showed that nearly all the mutant protein was unable to translocate to the nucleus to perform DNA repair activity. This novel mutant BRCA2 protein is dysfunction. CONCLUSIONS: We classify the mutation into disease causing and conclude that it is the risk factor for breast cancer in this family. So, conducting the same mutation test and providing genetic counseling for this family is practically meaningful and significant. Meanwhile, the identification of this new mutation enriches the Breast Cancer Information Core database, especially in China.

Construction of a disulfide-stabilized diabody against fibroblast growth factor-2 and the inhibition activity in targeting breast cancer.

Fibroblast growth factor-2 (FGF-2) is one of the most important angiogenic factors to promote tumor growth, progression and metastasis. Neutralizing antibodies against FGF-2 may suppress the growth of tumor cells by blocking the FGF-2 signaling pathway. In this study, a disulfide-stabilized diabody (ds-Diabody) that specifically targets FGF-2 was designed. Compared to its parent antibody, the introduction of disulphide bonds in the diabody could significantly increase the stability of ds-Diabody and maintain its antigen binding activity. The ds-Diabody against FGF-2 could effectively inhibit the tube formation and migration of vascular endothelial cells and block the proliferation and invasion of human breast cancer cells. In the mouse model of breast cancer xenograft tumors, the ds-Diabody against FGF-2 could significantly inhibit the growth of tumor cells. Moreover, the densities of microvessels stained with CD31 and lymphatic vessels stained with LYVE1 in tumors showed a significant decrease following treatment with the ds-Diabody against FGF-2. Our data indicated that the ds-Diabody against FGF-2 could inhibit tumor angiogenesis, lymphangiogenesis and tumor growth.

Hypermethylated ERG as a cell-free fetal DNA biomarker for non-invasive prenatal testing of Down syndrome.

BACKGROUND: Previous reports have shown that the ERG gene is hypermethylated in the placenta and hypomethylated in maternal blood cells. In this study, we explore the feasibility of hypermethylated ERG as a cell-free fetal (cff) DNA biomarker for non-invasive prenatal testing (NIPT) of Down syndrome. METHODS: We randomly selected 90 healthy pregnant women, including 30 cases at each trimester of pregnancy. In addition, 15 pregnant women were recruited as the case group whose fetuses had been confirmed to have trisomy 21 by amniotic fluid analysis at 18th to 26th week gestation. Using HpaII, MspІ to digest cell-free maternal plasma DNA, we performed SYBR Green PCR to detect methylated sites of ERG sequences, and analyzed the concentrations of cff DNA in maternal plasma in different gestational trimesters and the case group. RESULTS: The ERG median concentrations of the maternal plasma after Hpa II digestion (LG copies/ml) in first, second and third-trimesters were 5.38, 6.10, and 7.04, respectively (Kruskal-Wallis, P<0.01); and that in the trisomy 21 case group was 6.85, which was higher than the second-trimester (Mann-Whitney, P<0.01). CONCLUSIONS: The study demonstrated that ERG gene is hypermethylated in cff DNA but hypomethylated in maternal DNA; and the median concentration of ERG gene in the trisomy 21 case group is higher than that in the gestational trimester matched normal group. ERG gene, as a fetal DNA biomarker, may be useful for NIPT of Down syndrome.

Soluble production and function of vascular endothelial growth factor/basic fibroblast growth factor complex peptide.

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are important proangiogenic factors in tumor procession. The autocrine and paracrine bFGF and the VEGF in tumor tissue can promote tumor angiogenesis, tumor growth, and metastasis. A VEGF/bFGF Complex Peptide (VBP3) was designed on the basis of epitope peptides from both VEGF and bFGF to elicit in vivo production of anti-bFGF and anti-VEGF antibodies. In this study, we reported on the production of recombinant VBP3 using high cell density fermentation. Fed-batch fermentation for recombinant VBP3 production was conducted, and the production procedure was optimized in a 10-L fermentor. The fraction of soluble VBP3 protein obtained reached 78% of total recombinant protein output under fed-batch fermentation. Purified recombinant VBP3 could inhibit tumor cell proliferation in vitro and stimulate C57BL/6 mice to produce high titer anti-VEGF and anti-bFGF antibodies in vivo. A melanoma-grafted mouse model and an immunohistochemistry assay showed that tumor growth and tumor angiogenesis were significantly inhibited in VBP3-vaccinated mice. These results demonstrated that soluble recombinant VBP3 could be produced by large-scale fermentation, and the product, with good immunogenicity, elicited production of high-titer anti-bFGF and anti-VEGF antibodies, which could be used as a therapeutic tumor vaccine to inhibit tumor angiogenesis and tumor growth.

Use of PCR and reverse line blot hybridization macroarray based on 16S-23S rRNA gene internal transcribed spacer sequences for rapid identification of 34 mycobacterium species.

The aim of this study was to develop a PCR and reverse line blot hybridization (PCR-RLB) macroarray assay based on 16S-23S rRNA gene internal transcribed spacer sequences for the identification and differentiation of 34 mycobacterial species or subspecies. The performance of the PCR-RLB assay was assessed and validated by using 78 reference strains belonging to 55 Mycobacterium species, 219 clinical isolates which had been identified as mycobacteria by high-performance liquid chromatography or gas chromatography, three skin biopsy specimens from patients with suspected leprosy which had been shown to contain acid-fast bacilli, and isolates of 14 nonmycobacterial species. All mycobacteria were amplified in the PCR and hybridized with a genus-specific probe (probe MYC). The 34 species-specific probes designed in this study hybridized only with the corresponding Mycobacterium species. The mycobacterial PCR-RLB assay is an efficient tool for the identification of clinical isolates of mycobacteria; it can reliably identify mixed mycobacterial cultures and M. leprae in skin biopsy specimens.