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Breast cancer is one of the most common malignant tumors endangering women. It has been found that the subunits of the COP9 complex are closely related to the occurrence and development of malignant tumors, and the CSN4 subunit plays an important role in regulating the whole complex. In the breast cancer cell line MDA-MB-231, we successfully established a lentivirus-mediated CSN4-knockdown cell line. CCK8 cell proliferation assays and colony formation experiments confirmed that CSN4 knockdown significantly decreased the cellular proliferation rate. Cell cycle analysis showed that CSN4 knockdown increased sub-G1 population and induced apoptosis. In addition, Western blotting assays confirmed that CSN4 regulates the expression of CDK6 and Caspase3, suggesting that CSN4 modulates the proliferation and apoptosis of breast cancer cells by regulating the expression of CDK6 and Caspase3 genes and thereby tumorigenesis. This study has deepened our understanding of the molecular mechanism of apoptosis and cell growth in breast cancers, and further revealed the role and mechanism of CSN4 in cancer biology.

Platinum-based chemotherapy is an important treatment for non-small cell lung cancer. However, the effectiveness of the treatment varies among the patients. We investigated the association between DNA polymorphisms of the autophagy pathway and responses of such treatment among 1004 Chinese patients. Ninety-nine SNPs located on 13 genes of the autophagy pathway were genotyped and assessed for their association with clinical benefit, progression-free survival (PFS) and overall survival (OS). The results showed that rs7953348 (GA) (P=0.017, OR: 0.67, 95%CI: 0.49-0.93) and rs12303764 (AC) (P=0.009, OR: 0.63, 95%CI: 0.45-0.89) at the ULK1 gene, and rs17742719 (CA) (P=0.002, OR: 1.83, 95%CI: 1.26-2.66), rs8003279 (AG) (P=0.006, OR: 1.65, 95%CI: 1.16~2.35) and rs1009647 (GA) (P=0.002, OR: 1.70, 95%CI: 1.22-2.37) at the ATG14 gene were associated with clinical benefit. Polymorphisms at rs7955890 (GA) (P=0.004, HR: 0.63; 95%CI: 0.46-0.86) and rs17032060 (GA) (P=0.006, HR: 0.65, 95%CI: 0.48-0.88) at the DRAM gene, and rs13082005 (GA) (P=0.012, HR: 1.27, 95%CI: 1.05-1.53) at the ATG3 gene were significantly associated with PFS. We also found that rs7953348 (GA) (P=0.011, HR: 0.74, 95%CI: 0.58-0.93) at the ULK1 gene and rs1864183 (GA) (P=0.016, HR: 0.42, 95%CI: 0.21-0.85) at the ATG10 gene were associated with OS. Thus, the study demonstrated that the autophagy pathway might play important role(s) in platinum-based chemotherapy. DNA polymorphisms in its component genes can potentially be predictors for clinical responses of platinum-based chemotherapy among the patients with non-small lung cancer.

Hepatitis B virus (HBV) is a dented double-stranded DNA virus. After infecting human hepatic cells, it forms cccDNA that replicates persistently and integrates randomly into the host’s genome during the process of reserve transcription. On average, in each cell with chronic HBV infection, there are about 33 copies of cccDNA with a half of 35-57 days, which can be difficult to eradicate. A new strategy is to inhibit HBV transcription by using locked nucleic acid (LNA). Besides, cleaving HBV genome by targeted genome editing technologies could potentially cure patients. In this study, we explored new genome editing tools for HBV treatment. Based on LNA’s ability to form triple helix by binding to duplex DNA, its stability towards nuclease and polymerase, and its sensitivity to single base mismatches, we designed LNA-modified oligonucleotides as DNA binding domain to effectively increase the specificity of target gene recognition. Meanwhile, by utilizing the small molecular weight and dimerization dependent activity of nuclease Fok I, we used Fok I recombinant dimer protein as DNA cleavage domain. Here, we established a method by chemical coupling of LNA-oligonucleotide with Fok I cleavage domain, and also validated the targeted cleavage of HBV genes with our new tools in vitro. These results provide new possibilities for future in vivo anti-virus gene therapy with high specificity and no integration risk.

The traditional Type Ⅱ restriction enzyme-based method is restricted by the purification steps, and therefore, cannot be applied to specific DNA assembly in chaotic system. To solve this problem, Thermostable Ligase Chain Reaction (TLCR) was introduced in the process of DNA assembly and capture. This technique combines the feature of thermostable DNA ligase and sequence specific oligo ligation template, "Helper", to achieve specific assembly of target fragments and exponential increase of products in multiple thermocyclings. Two plasmid construction experiments were carried out in order to test the feasibility and practical performance of TLCR. One was that, TLCR was used to specifically capture a 1.5 kb fragment into vector from an unpurified chaotic system which contained 7 different sizes of fragments. The results showed that the capturing accuracy was around 80%, which proved the feasibility and accuracy of using TLCR to specific assembly of DNA fragments in a complicated mixed system. In the other experiment, TLCR was used to capture two fragments (total length was 27 kb) from Hind Ⅲ digestion of Lambda genome into vector by order. The results also showed an accuracy of around 80%. As demonstrated in the results, TLCR can simplify the process of DNA recombination experiments and is suitable for the assembly of multiple and large DNA fragments. This technique can provide convenience to biological experiments.

Hemophilia B, or the Christmas disease, is a common human disease caused by coagulation factor Ⅸ (FⅨ) deficiency. It is an X-linked recessive hereditary disease. Here we obtained FⅨ-knockout mouse strains with phenotype of hemophilia B with the CRISPR/Cas system efficiently. We chose the 8th exon as the target locus, and co-injected codon-optimized Cas9 mRNA with sgRNA of FⅨ into C57BL/6 mice zygotes. We obtained 60 mice in total and genotyped them by high resolution melting (HRM) and sequencing. The results showed the mutation rate was 85.0% in total, and 79.5% and 95.2% in males and females, respectively. No off-targets were detected in the similar locus by HRM. We future measured the FⅨ activity of each mice. The FⅨ: C of mutant mice were significantly below the normal level and reduced to 6.82% of wild-type mice. The activity assay demonstrated that all the mutant mice were lack of FⅨ. In summary, we have generated hemophilia B model mice with extreme efficiency, using the RNA-guided Cas9 nuclease gene editing system.

Clopidogrel is a widely used anti-platelet agent for the prevention of arterial thrombosis. It has been suggested that clopidogrel may be less effective in inhibiting platelet aggregation among patients who are carriers of CYP2C19*2 and CYP2C19*3, two loss-of-function CYP2C19 alleles, which are associated with reduced conversion of clopidogrel to its active metabolite. The objective of this research was to develop a simple and accurate method for genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube using high-resolution melting curve (HRM) analysis. Two amplicons bracketing CYP2C19*2 and CYP2C19*3 gene variants were designed, and AT- or GC-rich 5' tails were added to selected primers to ensure two different amplicons with non-overlapping melting curves. Sixty-four random DNA samples were all fast and sensitively genotyped by HRM analysis. This method was validated by DNA sequencingtechnique, and genotypes obtained using the HRM approach perfectly matched the genotypes obtained by DNA sequencing technique. Therefore, this HRM-based assay allows simple and accurate duplex genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube. This method is expected to be applied in clinical laboratory to guide indi-vidual dosage design of clopidogrel.

To investigate the association between chromosome 8p11 (CHRNB3-CHRNA6) polymorphisms and lung cancer susceptibility in Chinese Han population, we genotyped 6 tag SNPs variants of this region among 784 patients with lung cancer and 782 age- and sex-matched cancer-free control participants to screen for any risk-associated SNPs. The results revealed that rs16891561 TT genotype had a protective effect against lung cancer in people over 60 years old (adjusted OR=0.42, 95% CI=0.20-0.88; P=0.022), female groups (adjusted OR=0.34, 95% CI=0.13-0.87; P=0.025), and non-smoking people (adjusted OR=0.32, 95% CI=0.13-079; P=0.013). Additionally, rs4236926 TT genotype had a protective effect against lung cancer in people over 60 years old (adjusted OR=0.48, 95% CI=0.23-0.99; P=0.048) and non-smoking people (adjusted OR=0.32, 95% CI=0.13-0.80; P=0.014). According to pathological type of lung cancer, these two SNPs were associated with adenocarcinomas susceptibility. As to cumulative effect of rs4236926 and rs16891561, in non-smokers strata, lung cancer risk was significantly reduced in those who had 3-4 mutant alleles (adjusted OR=0.29, 95% CI=0.11-0.71; P=0.007). Furthermore, people containing 3-4 mutant alleles had lower level of smoking doses (mean pack-year=13.2) compared with others. In conclusion, 8p11 (CHRNB3-CHRNA6) polymorphisms are related to smoking behavior and lung cancer susceptibility in Chinese Han population.