Nucleotide variants of genes encoding components of the Wnt signalling pathway and the risk of non-syndromic tooth agenesis.

Tooth agenesis is one of the most common dental anomalies, with a complex and not yet fully elucidated aetiology. Given the crucial role of the Wnt signalling pathway during tooth development, the purpose of this study was to determine whether nucleotide variants of genes encoding components of this signalling pathway might be associated with hypodontia and oligodontia in the Polish population. A set of 34 single nucleotide polymorphism (SNPs) in 13 WNT and WNT-related genes were analyzed in a group of 157 patients with tooth agenesis and a properly matched control group (n = 430). In addition, direct sequencing was performed to detect mutations in the MSX1, PAX9 and WNT10A genes. Both single-marker and haplotype analyses showed highly significant association between SNPs in the WNT10A gene and the risk for tooth agenesis. Moreover, nine pathogenic mutations within the coding region of the WNT10A gene were identified in 26 out of 42 (62%) tested patients. One novel heterozygous mutation was identified in the PAX9 gene. Borderline association with the risk of non-syndromic tooth agenesis was also observed for the APC, CTNNB1, DVL2 and WNT11 polymorphisms. In conclusion, nucleotide variants of genes encoding important components of the Wnt signalling pathway might influence the risk of tooth agenesis.

Single nucleotide polymorphism of CD40 region and the risk of systemic lupus erythematosus.

There is one study on the association of the CD40 G > T (rs4810485) single nucleotide polymorphism (SNP) as a risk factor of systemic lupus erythematosus (SLE). Therefore, we studied the prevalence of the CD40 G > T SNP in patients with SLE (n = 261) and controls (n = 545) in a Polish population. We did not find significant differences between the CD40 G > T genotype and allele frequency in patients with SLE and healthy individuals. However, the frequency of the CD40 TT and GT genotypes was statistically different between patients with arthritis and neurologic manifestations and patients without these symptoms (OR = 0.2009 (95% CI = 0.07547-0.5348, p = 0.0004, p (corr) = 0.0068) and OR = 0.2876 (95% CI = 0.1371-0.6031, p = 0.0005, p (corr) = 0.0085) respectively). Our observations indicate that the CD40 T variant might be negatively associated with some clinical disease manifestations in patients with SLE.

The c.1460C>T polymorphism of MAO-A is associated with the risk of depression in postmenopausal women.

OBJECTIVE: The aim of the study was an evaluation of possible relationships between polymorphisms of serotoninergic system genes and the risk of depression in postmenopausal women. METHODS: We studied 332 women admitted to our department because of climacteric symptoms. The study group included 113 women with a diagnosis of depressive disorder according to the Hamilton rating scale for depression; the controls consisted of 219 women without depression. Serum 17ß-estradiol concentrations were evaluated using radioimmunoassay, while polymorphisms in serotoninergic system genes: serotonin receptors 2A (HTR2A), 1B (HTR1B), and 2C (HTR2C); tryptophan hydroxylase 1 (TPH1) and 2 (TPH2), and monoamine oxidase A (MAO-A) were evaluated using polymerase chain reaction-restriction. RESULTS: We found that the 1460T allele of MAO-A c.1460C>T (SNP 1137070) appeared with a significantly higher frequency in depressed female patients than in the control group (P = 0.011) and the combined c.1460CT + TT genotypes were associated with a higher risk of depression (P = 0.0198). Patients with the 1460TT genotype had a significantly higher 17ß-estradiol concentration than patients with the 1460CT genotype (P = 0.0065) and 1460CC genotype (P = 0.0018). CONCLUSIONS: We concluded that depression in postmenopausal women is closely related to the genetic contribution of MAO-A.

Interleukin-18 promoter polymorphisms in patients with systemic lupus erythematosus.

OBJECTIVES: The role of various polymorphisms located in the IL-18 promoter has not yet been defined with regards to patient susceptibility to SLE, and occurrence of clinical manifestations of the disease remains inconsistent. METHODS: Using PCR-RFLP and DNA sequencing analysis we studied the frequency of -137 G/C (rs187238), -607 C/A (rs1946518) and -1297C/T (rs360719) polymorphisms in IL-18 promoter in patients with SLE from a sample of the Polish population. RESULTS: We observed that patients with SLE bearing the IL-18 -1297CC genotype exhibited a 2.536-fold increased risk of SLE incidence (95% CI=1.333-4.826, p=0.0035). We also found a significantly higher frequency of the IL-18 -1297C allele in patients than in controls, with odds ratio (OR) for the IL-18 -1297C allele in patients with SLE being 1.558 (95% CI=1.189-2.041, p=0.0013). Moreover, there was an association between the IL-18 -1297CC genotype and renal manifestations of SLE, OR=3.792 (1.446-9.947, p=0.0051). However, we did not find any contribution of the IL-18 -607 C/A and -137 G/C polymorphisms to SLE incidence or occurrence of the studied SLE manifestations. CONCLUSIONS: Our findings confirmed that the IL-18 -1297C gene variant may contribute to the risk of SLE incidence. Moreover, IL-18 -1297CC might be associated with renal manifestations of SLE.

CD24 Ala57Val gene polymorphism and the risk of systemic lupus erythematosus.

It was recently shown that the CD24 Ala57Val (rs 52812045) polymorphism plays a significant role in susceptibility to systemic lupus erythematosus (SLE) in a Spanish population, which has not been confirmed in other ethnic groups. We investigated the distribution of the CD24 Ala57Val polymorphism in patients with SLE (n = 250) and controls (n = 350) in Poland. The odds ratio (OR) for patients with SLE with the Ala/Val genotype compared with Ala/Ala genotype was 1.490 [95% confidence interval (CI) = 1.052-2.111, P = 0.0275], and OR for the Val/Val genotype compared with Ala/Ala genotypes was 2.001 (95% CI = 1.154-3.467, P = 0.0154). Moreover, we observed a significant association between the CD24 Val allele and the presence of anti-Scl-70 antibody (Ab) OR = 2.155 (1.438-3.229, P = 0.0002). There was also an association of Val allele with the presence of anti-snRNP Ab OR = 1.984 (1.266-3.110, P = 0.0034) in patients with SLE. We also found that the CD24 Val/Val and Ala/Val genotypes contribute to immunologic manifestations OR = 2.244 (1.323-3.806, P = 0.0037). Our observations indicate that the CD24 Ala57Val polymorphism may predispose to SLE incidence and can be linked to immunologic manifestations and production of autoantibodies in this disease.

The CD3Z 844 T>A polymorphism within the 3'-UTR of CD3Z confers increased risk of incidence of systemic lupus erythematosus.

Recently, a family-based association analysis showed that the haplotype carrying a low expression of the variant CD3Z 844 T>A (rs1052231) polymorphism located in the 3'-untranslated region of CD3Z predisposes to systemic lupus erythematosus (SLE) incidence. We analyzed the prevalence of the CD3Z 844 T>A polymorphism in SLE patients (n = 152) and controls (n = 304) in Poland. We observed that women with the CD3Z AA and CD3Z AT genotypes exhibited a 1.845-fold increased risk of SLE [95% confidence intervals (95% CI) = 1.222-2.787, P = 0.0038]. However, we did not find an increased risk for the homozygous CD3Z AA genotype (odds ratio = 1.204, 95% CI = 0.2838-5.108, P = 1.0000). This observation confers that genetic factors causing a decreased level of CD3-zeta in T cells may predispose to SLE incidence.

Contribution of the R620W polymorphism of protein tyrosine phosphatase non-receptor 22 to systemic lupus erythematosus in Poland.

The protein tyrosine phosphatase non-receptor 22 (PTPN22) 1858 C>T poly-morphic variant gene (rs2476601) displays an association with systemic lupus erythematosus (SLE) and other autoimmune diseases. However, its contribution to SLE has been found to be disputable. We therefore examined the association of PTPN22 1858 C>T polymorphism with susceptibility to SLE in the Polish population, among patients with SLE (n=150) and controls (n=300). We found a contribution of the PTPN22 1858 C>T polymorphism to the incidence of SLE. Women with the PTPN22 TT and PTPN22 CT genotypes displayed a 2.016-fold increased risk of SLE (95% CI=1.324 - 3.070, P=0.0014). However, we did not observe an increased risk for the homozygous PTPN22 TT genotype OR= 2.552 (95% CI=0.6748-9.64, p=0.1675). Our results confirm an association of the 1858 C>T polymorphism of the PTPN22 gene with SLE, which was previously observed in other populations.

Polymorphic variants of genes encoding MTHFR, MTR, and MTHFD1 and the risk of depression in postmenopausal women in Poland.

OBJECTIVE: Disturbances in the folate-dependent one-carbon metabolism have been reported in depression. Polymorphic variants of genes encoding key enzymes of folate and methionine metabolism may have an impact on catecholamine catabolism conducted by catechol-O-methyltransferase. METHODS: The distribution of polymorphisms of genes encoding methylenetetrahydrofolate reductase (MTHFR); methionine synthase (MTR); 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase (MTHFD1) was examined in postmenopausal women with (n=83) and without depression (n=89). RESULTS: We found a significant contribution of the MTHFR 677C>T polymorphic variants to depression in postmenopausal women. Odds ratio (OR) for women with depression and MTHFR TT genotype was 3.478 (95% CI=1.377-8.783), P=0.0096 and OR of the TT and CT genotypes was 2.345 (95% CI=1.258-4.373), P=0.0086. Moreover, after stratification based on depression severity in postmenopausal women, we found that the MTHFR TT genotype displayed a 4.831-fold increased risk of moderate and severe depression (95% CI=1.975-11.820, P=0.0008). We did not observe statistical differences in the distribution of MTR 2756A>G and MTHFD1 1958G>A polymorphic variants in groups of postmenopausal women with and without depression. However, the MTR GG genotype exhibited a 5.750-fold increased risk of moderate and severe depression in postmenopausal women (95% CI=1.547-21.379, P=0.013). CONCLUSIONS: Our findings indicate a significant role of folate and possible methionine metabolism involvement in the development of depression in postmenopausal women.

Tamoxifen epigenetically modulates CXCL12 expression in MCF-7 breast cancer cells.

The CXCL12 chemokine binds to the CXCR4 receptor and contributes to survival, proliferation, and migration of malignant cells. Recent reports indicate that breast cancer cells lacking expression of CXCL12 but exhibiting CXCR4 can metastasize to target organs that secrete CXCL12. We observed that Tamoxifen (Tam), similarly to 5-dAzaC, results in significantly increased levels of CXCL12 transcript and protein in MCF-7 breast cancer cells. Bisulfite sequencing suggests that Tam, similarly to 5-dAzaC, may increase CXCL12 expression via reduction in methylation of cytosine in the cytosine-guanosine (CpG) dinucleotide island of the CXCL12 promoter of MCF-7 cells. Our results, together with findings of other researches, may suggest that Tam epigenetically activates CXCL12 expression in breast cancer cells and can make these cells less susceptible to attraction by exogenous CXCL12 to metastasis sites.

Increased CXCR4 expression in AsPC1 pancreatic carcinoma cells with RNA interference-mediated knockdown of DNMT1 and DNMT3B.

The effect of DNA methylation on CXCR4 expression has been demonstrated in pancreatic cancer and melanoma cells, but little is known about the effect of DNA methyltransferases 1 and 3 (DNMT1 and DNMT3B) on CXCR4 expression. Employing lentiviral vectors, we created stable RNA interference-mediated knockdown of DNMT1 and DNMT3B in AsPC1 pancreatic cancer cells. Using reverse transcription real-time quantitative PCR and flow cytometric analysis, we evaluated the increase in the expression of CXCR4 transcript and protein levels in these cells. Bisulfite sequencing analysis showed that the level of promoter demethylation appeared more effective in cells with knockdown of DNMT1 than in those with DNMT3B knockdown. Furthermore, the combined RNA interference knockdown of both DNMT1 and DNMT3B increased promoter demethylation, leading to a slight increase in CXCR4 expression. However, the demethylating agent 5-Aza-2'-deoxycytidine exhibited the strongest effect on promoter demethylation, which correlated with the highest production of CXCR4 transcript and protein in AsPC1 cells. Our results indicate that DNMT1 plays the main role in maintenance of methylation of CXCR4 promoter, while DNMT3B may function as an accessory DNA methyltransferase to modulate CXCR4 expression in AsPC1 cells.

Down-regulation of CXCR4 expression by tamoxifen is associated with DNA methyltransferase 3B up-regulation in MCF-7 breast cancer cells.

The CXCR4 chemokine receptor is a seven transmembrane G protein-coupled receptor present on the surface of various cells including cancer cells. The CXCR4 receptor contributes to the induction of several intracellular signalling pathways that enhance survival, proliferation, and migration of malignant cells. We observed that tamoxifen (Tam) reduced the CXCR4 transcript and protein levels in MCF-7 breast cancer cells. However, we did not see a Tam effect on CXCR4 transcript and protein levels in MCF-7(LVMT3B) cells with RNA interference-mediated knockdown of DNMT3B. We also observed that Tam significantly increased, for several hours, the expression of enzymatically active DNMT3B splice variants in MCF-7 cells. However, there was no Tam effect on these DNMT3B splice variants' expression in MCF-7(LVMT3B) cells. Bisulfite sequencing suggests that Tam may reduce CXCR4 expression via increased methylation of cytosine in the cytosine-guanosine (CpG) dinucleotide island of the CXCR4 promoter of MCF-7 breast cancer cells. Our findings suggest that Tam induces an increase in DNMT3B expression that is associated with the increase of CpG dinucleotide methylation in the CXCR4 promoter and significant reduction of CXCR4 gene expression in MCF-7 cells.

Contribution of polymorphism in codon 72 of p53 gene to systemic lupus erythematosus in Poland.

The contribution of the p53 Arg72Pro polymorphism in the development of systemic lupus erythematosus (SLE) remains controversial. We investigated the frequency of the p53 Arg72Pro genotype in patients with SLE (n = 155) and in controls (n = 150) in Poland. We found a weak contribution of the Arg/Arg genotype to the morbidity of SLE. Odds ratio (OR) for patients with SLE and p53 Arg/Arg genotype was 1.875 [95% CI = 1.180-2.979], P = 0.0075 and OR of the Arg/Arg and Arg/Pro genotypes was 1.549 [95% CI = 0.752-3.195], P = 0.2328. Since the p53Arg variant supports apoptosis better than the p53Pro variant, our findings can be linked to an increase in the number of apoptotic leucocytes in SLE patients. The distinction between various populations may be because of differences in racial composition and/or exposure to distinct environmental factors that have a different impact on SLE incidence along with the changed Argp53Pro genotype.