Breast cancer association studies in a Han Chinese population using 10 European-ancestry-associated breast cancer susceptibility SNPs

A systematic analysis of the association studies between CASP8 D302H polymorphisms and breast cancer risk

Caspase 8 (CASP8) is a regulator of apoptosis, whose genetic variation has been reported to be associated with the risk of various cancers. Especially, the single-nucleotide polymorphism (SNP) rs1045485, which generates the substitution D302H in CASP8, is likely to be associated with breast cancer. Several previous studies have reported the association of CASP8 D302H polymorphism with breast cancer; however, the results are inconsistent. To validate the association between CASP8 D302H polymorphism and breast cancer risk, we performed an updated meta-analysis of 18 studies including 27,807 cases and 32,332 controls. We tested the overall association between this SNP and breast cancer susceptibility and stratified subgroups based on countries where cases are from. We confirmed a significant correlation between CASP8 D302H polymorphism and the reduced breast cancer susceptibility in population from UK, Germany and Poland, but no significant association was observed in other countries, such as Finland or USA. Our findings indicate the relationship of SNP CASP8 D302H and breast cancer would not be universal but only be sensitive in some particular European countries. The genetic difference for diverse countries may be useful in individual and precision medicine or health.

Lipopolysaccharide modulates p300 and Sirt1 to promote PRMT1 stability via an SCFFbxl17-recognized acetyldegron

E3 ubiquitin ligase recognizes its protein substrates via specific molecular signatures for ubiquitin proteasomal degradation. However, the role of acetylation/deacetylation in the process of E3 ubiquitin ligase recognizing its protein substrates is not fully studied. Here, we report that a tandem IK motif in protein arginine methyltransferase 1 (PRMT1) forms an acetyldegron to recruit the F-box/LRR-repeat protein 17 (FBXL17), a component of the SKP1-CUL1-F-box protein (SCF)-type E3 ubiquitin ligase complex. PRMT1 is polyubiquitylated for proteasome degradation with a half-life of approximately 4 h in lung epithelial cells. SCF^Fbxl17 mediates PRMT1 polyubiquitylation at K117. SCF^Fbxl17 specifically binds PRMT1 via a unique motif IKxxxIK. Strikingly, the acetylation/deacetylation status of the lysine residues within the motif determines Fbxl17 binding. Deacetylation on both K200 and K205 by Sirtuin 1 (Sirt1) and acetylation of p300 (EP300) on K205 collaboratively prepare the motif for SCF^Fbxl17 binding thereby triggering PRMT1 protein degradation. Pathogen-derived lipopolysaccharide (LPS) downregulates Sirt1 and p300 to protect PRMT1 from degradation. This study demonstrates that LPS promotes PRMT1 stability by blockade of PRMT1 and SCF^Fbxl17 binding via an acetylation/deacetylation-modified acetyldegron; and LPS-elevated levels of PRMT1 lead to bronchial epithelial cell overgrowth in pulmonary inflammatory diseases.

The Associations of Genetic Variants in E-cadherin Gene With Clinical Outcome of Epithelial Ovarian Cancer

Objective

The E-cadherin protein plays major roles in tumor progression, invasion, and metastasis. Polymorphisms located in the E-cadherin gene (CDH1) may contribute to increased risks of specific cancers. In this study, we evaluated the associations between genetic variants inCDH1and the clinical outcomes of patients with epithelial ovarian cancer (EOC).

Materials and Methods

We assessed the−160C/Aand−347G/GApolymorphisms in the promoter region, as well as the3′-UTR +54C/Tpolymorphism of E-cadherin, in 257 patients with EOC by ligase detection reaction–polymerase chain reaction.

Results

Multivariate analysis showed that patients with EOC with theCDH1 −347GA/GAgenotype had shorter progression-free survival and overall survival (hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.06–4.40 and HR, 2.06; 95% CI, 1.01–4.19, respectively) compared to those carrying the G/G genotype. Likewise, the patients with theCDH1 −160A/Agenotype had a shorter progression-free survival than those with the C/C genotype (HR, 4.12; 95% CI, 1.43–111.88). No significant association was detected between theCDH1 3′-UTR +54C/Tpolymorphism and survival of the patients with EOC.

Conclusions

TheCDH1 −347GA/GAand−160A/Agenotypes may be prognostic markers that can help to identify patients at increased risk of invasive/metastatic cancer in northern China.

A pilot genome-wide association study of breast cancer susceptibility loci in Indonesia

Genome-wide association studies (GWASs) of the entire genome provide a systematic approach for revealing novel genetic susceptibility loci for breast cancer. However, genetic association studies have hitherto been primarily conducted in women of European ancestry. Therefofre we here performed a pilot GWAS with a single nucleotide polymorphism (SNP) array 5.0 platform from Affymetrix® that contains 443,813 SNPs to search for new genetic risk factors in 89 breast cancer cases and 46 healthy women of Indonesian ancestry. The case-control association of the GWAS finding set was evaluated using PLINK. The strengths of allelic and genotypic associations were assessed using logistic regression analysis and reported as odds ratios (ORs) and P values; P values less than 1.00x10(-8) and 5.00x10(-5) were required for significant association and suggestive association, respectively. After analyzing 292,887 SNPs, we recognized 11 chromosome loci that possessed suggestive associations with breast cancer risk. Of these, however, there were only four chromosome loci with identified genes: chromosome 2p.12 with the CTNNA2 gene [Odds ratio (OR)=1.20, 95% confidence interval (CI)=1.13-1.33, P=1.08x10(-7)]; chromosome 18p11.2 with the SOGA2 gene (OR=1.32, 95%CI=1.17-1.44, P=6.88x10(-6)); chromosome 5q14.1 with the SSBP2 gene (OR=1.22, 95%CI=1.11-1.34, P=4.00x10(-5)); and chromosome 9q31.1 with the TEX10 gene (OR=1.24, 95%CI=1.12-1.35, P=4.68x10(-5)). This study identified 11 chromosome loci which exhibited suggestive associations with the risk of breast cancer among Indonesian women.

Investigation of the association of Vogt-Koyanagi-Harada syndrome with IL23R-C1orf141 in Han Chinese Singaporean and ADO-ZNF365-EGR2 in Thai

BACKGROUND

We performed a multistage genome-wide association study of Vogt-Koyanagi-Harada (VKH) syndrome in a Han Chinese population and identified two novel non-human leukocyte antigen candidate regions previously. The aim of the study was to replicate the association of IL23R-C1orf141 and ADO-ZNF365-EGR2 with VKH syndrome in four sets of multinational populations in Asia.

METHOD

We conducted a candidate genes association study involving 185 patients with VKH syndrome and 287 normal controls from Han Chinese Singaporeans, non-Han Chinese, Thais and Koreans. Genotyping of 16 single nucleotide polymorphisms (SNPs) within IL23R-C1orf141 and ADO-ZNF365-EGR2 loci was performed using the Sequenom MassARRAY system or by Taqman SNP assays.

RESULTS

Eight SNPs in IL23R-Clorf141 showed an association with VKH syndrome only in Han Chinese Singaporeans (p=8.49×10(-5) to 1.02×10(-3), pcorrection=1.69×10(-4) to 2.04×10(-3)) but not in the other groups tested. One SNP rs1884444 in IL23R-Clorf141 was found to be weakly associated with VKH syndrome in the Han Chinese Singaporeans, but significance was lost following Bonferroni correction for multiple comparisons. Five SNPs in ADO-ZNF365-EGR2 were found to be associated with VKH syndrome in Thai patients with VKH (p=0.014, pc=0.028) but not in the other three ethnic groups tested.

CONCLUSIONS

This study confirmed the genetic associations between SNPs in IL23R-C1orf141 and VKH syndrome in Han Chinese Singaporeans but not in other Asian populations. In addition, we also successfully replicated the association of VKH syndrome with ADO-ZNF365-EGR2 in a Thai population.

A functional SNP in the MDM2 promoter mediates E2F1 affinity to modulate cyclin D1 expression in tumor cell proliferation

BACKGROUND

The MDM2 oncogene, a negative regulator of p53, has a functional polymorphism in the promoter region (SNP309) that is associated with multiple kinds of cancers including non-melanoma skin cancer. SNP309 has been shown to associate with accelerated tumor formation by increasing the affinity of the transcriptional activator Sp1. It remains unknown whether there are other factors involved in the regulation of MDM2 transcription through a trans-regulatory mechanism.

METHODS

In this study, SNP309 was verified to be associated with overexpression of MDM2 in tumor cells. Bioinformatics predicts that the T to G substitution at SNP309 generates a stronger E2F1 binding site, which was confirmed by ChIP and luciferase assays.

RESULTS

E2F1 knockdown downregulates the expression of MDM2, which confirms that E2F1 is a functional upstream regulator. Furthermore, tumor cells with the GG genotype exhibited a higher proliferation rate than TT, correlating with cyclin D1 expression. E2F1 depletion significantly inhibits the proliferation capacity and downregulates cyclin D1 expression, especially in GG genotype skin fibroblasts. Notably, E2F1 siRNA effects could be rescued by cyclin D1 overexpression.

CONCLUSION

Taken together, a novel modulator E2F1 was identified as regulating MDM2 expression dependent on SNP309 and further mediates cyclin D1 expression and tumor cell proliferation. E2F1 might act as an important factor for SNP309 serving as a rate-limiting event in carcinogenesis.