Abstract MIP-071: TARGETING A CHEMORESISTANT OVARIAN CANCER CELL POPULATION VIA THE CARBOHYDRATE ANTIGEN SIALYL TN

Key words: Sialyl Tn, drug resistance, antibody-drug conjugates, cancer stem cells

OBJECTIVES: A successful therapeutic strategy for ovarian cancer will require direct targeting of inherently chemoresistant tumor cells which are comprised in part of cancer stem cells (CSCs) that survive current cytotoxic treatment regimes and drive tumor resurgence. The sialyl-Tn (STn) antigen is a carbohydrate moiety present on tumor cells but rarely seen in normal adult tissue. Importantly, STn has been shown to be present on CSCs in pancreatic, colon, and gastric malignancies. Our objective was to assess the expression of STn and the known CSC marker CD133 in human ovarian cancer (OvCa) cell lines and primary serous carcinomas, and evaluate the ability of STn+ and STn- cells to both grow in an anchorage independent manner and survive standard-of-care cytotoxic therapy. Furthermore, we sought to assess the effect of murine and humanized α -STn antibody-drug conjugates (ADCs) on OvCa cells in vitro and tumor viability in vivo.

METHODS: STn and CD133 expression in established OvCa cell lines was analyzed by flow cytometry. STn-CD133-, STn+CD133-, STn-CD133+ and STn+CD133+ cells were purified from OVCAR3 and OVCAR4 by FACS, plated in soft agar, and incubated for 21 days. Colony forming efficiency of each sub-population was calculated. Unsorted cells were treated in vitro with either murine α -STn-monomethyl auristatin E (MMAE) ADC or vehicle control and cell viability was assessed by MTT assay. Subsequently, cells were treated in vitro with α -STn-MMAE, paclitaxel and carboplatin, or appropriate controls, and the profile of cells surviving 72 hours post-treatment was determined by flow cytometric analysis. Finally, OVCAR3-derived mouse xenografts were treated with murine and humanized α-STn-MMAE, unconjugated mAbs alone, and vehicle control. Mice were assessed regularly for tumor growth and cytotoxic effects.

RESULTS: In the OvCa cell lines OV90, OVCAR3 and OVCAR4, when grown in traditional 2D culture, STn+ cells comprised 98.4%, 40.0%, and 26.4% of the total cell population, respectively. In each of these cell lines, we readily detected STn+CD133+ sub-populations suggesting that STn is expressed on CD133+ ovarian CSCs. Colony formation assays analyzing FACS-purified STn-CD133-, STn+CD133-, STn-CD133+ and STn+ CD133+ sub-populations suggest that STn expression correlates with anchorage independent growth, a characteristic of cell stemness. Paclitaxel and carboplatin treatment in vitro significantly increased the proportion of STn+ and CD133+ cells, demonstrating the chemoresistant characteristics of these cells. Treatment with the murine α-STn-MMAE ADCs reduced the viability of OvCa cell lines in vitro in a dose-dependent manner. Treatment with murine and humanized α -STn- MMAE antibodies in vivo reduced tumor volumes, whereas vehicle treatment did not impede tumor growth. Interestingly, the unconjugated antibody also had a modest negative impact on tumor volume.

CONCLUSION: A novel, highly specific STn antibody identifies the STn antigen in OvCa cell lines and patient samples. STn+ and CD133+ cells demonstrate stem-like characteristics such as anchorage-independent growth and chemoresistance. STn ADCs decreased cell viability in vitro and reduced tumor volumes in vivo, suggesting that specific therapeutic targeting of STn in ovarian tumors may be an effective clinical strategy to eliminate quiescent CSCs.

Citation Format: B.R. Rueda, K. Starbuck, D. Eavarone, J. Prendergast, J. Stein, R. Foster, J. Behrens. TARGETING A CHEMORESISTANT OVARIAN CANCER CELL POPULATION VIA THE CARBOHYDRATE ANTIGEN SIALYL TN [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr MIP-071.

A rare polymorphism in the gene for Toll-like receptor 2 is associated with systemic sclerosis phenotype and increases the production of inflammatory mediators

OBJECTIVE

To investigate whether polymorphisms in Toll-like receptor (TLR) genes, previously reported to be associated with immune-mediated diseases, are involved in systemic sclerosis (SSc).

METHODS

We genotyped 14 polymorphisms in the genes for TLRs 2, 4, 7, 8, and 9 in a discovery cohort comprising 452 SSc patients and 537 controls and a replication cohort consisting of 1,170 SSc patients and 925 controls. In addition, we analyzed 15-year followup data on 964 patients to assess the potential association of TLR variants with the development of disease complications. We analyzed the functional impact of the associated polymorphism on monocyte-derived dendritic cells.

RESULTS

In the discovery cohort, we observed that a rare functional polymorphism in TLR2 (Pro631His) was associated with antitopoisomerase (antitopo) positivity (odds ratio 2.24 [95% confidence interval 1.24-4.04], P=0.003). This observation was validated in the replication cohort (odds ratio 2.73 [95% confidence interval 1.85-4.04], P=0.0001). In addition, in the replication cohort the TLR2 variant was associated with the diffuse subtype of the disease (P=0.02) and with the development of pulmonary arterial hypertension (PAH) (Cox proportional hazards ratio 5.61 [95% confidence interval 1.53-20.58], P=0.003 by log rank test). Functional analysis revealed that monocyte-derived dendritic cells carrying the Pro63His variant produced increased levels of inflammatory mediators (tumor necrosis factor α and interleukin-6) upon TLR-2-mediated stimulation (both P<0.0001).

CONCLUSION

Among patients with SSc, the rare TLR2 Pro631His variant is robustly associated with antitopoisomerase positivity, the diffuse form of the disease, and the development of PAH. In addition, this variant influences TLR-2-mediated cell responses. Further research is needed to elucidate the precise role of TLR-2 in the pathogenesis of SSc.

Analysis of the influence of PTPN22 gene polymorphisms in systemic sclerosis

OBJECTIVE

Two functional single nucleotide polymorphisms (SNP) in the PTPN22 gene (rs24746601 and rs33996649) have been associated with autoimmunity. The aim of this study was to investigate the role of the R263Q SNP for the first time and to re-evaluate the role of the R620W SNP in the genetic predisposition to systemic sclerosis (SSc) susceptibility and clinical phenotypes.

METHODS

3422 SSc patients (2020 with limited cutaneous SSc and 1208 with diffuse cutaneous SSc) and 3638 healthy controls of Caucasian ancestry from an initial case--control set of Spain and seven additional independent replication cohorts were included in our study. Both rs33996649 and rs2476601 PTPN22 polymorphisms were genotyped by TaqMan allelic discrimination assay. A meta-analysis was performed to test the overall effect of these PTPN22 polymorphisms in SSc.

RESULTS

The meta-analysis revealed evidence of association of the rs2476601 T allele with SSc susceptibility (p(FDRcorrected)=0.03 pooled, OR 1.15, 95% CI 1.03 to 1.28). In addition, the rs2476601 T allele was significantly associated with anticentromere-positive status (p(FDRcorrected)=0.02 pooled, OR 1.22, 95% CI 1.05 to 1.42). Although the rs33996649 A allele was significantly associated with SSc in the Spanish population (p(FDRcorrected)=0.04, OR 0.58, 95% CI 0.36 to 0.92), this association was not confirmed in the meta-analysis (p=0.36 pooled, OR 0.89, 95% CI 0.72 to 1.1).

CONCLUSION

The study suggests that the PTPN22 R620W polymorphism influences SSc genetic susceptibility but the novel R263Q genetic variant does not. These data strengthen evidence that the R620W mutation is a common risk factor in autoimmune diseases.

The FAS -670A>G polymorphism influences susceptibility to systemic sclerosis phenotypes

OBJECTIVE

To investigate the possible role of the FAS -670A>G functional polymorphism in the genetic predisposition to systemic sclerosis (SSc) susceptibility or clinical phenotype.

METHODS

A total of 2,900 SSc patients and 3,186 healthy controls were included in this study. We analyzed the genotype and allele frequencies of the FAS -670A>G polymorphism in 9 distinct ethnic cohorts, including 6 cohorts of European ancestry (a Spanish cohort of 228 SSc patients and 265 controls, a Dutch cohort of 203 SSc patients and 277 controls, a German cohort of 313 SSc patients and 247 controls, an Italian cohort of 323 SSc cases and 89 controls, a British cohort of 269 SSc patients, and a Swedish cohort of 182 patients) and 3 distinct ethnic cohorts from the US (a cohort of 1,047 white patients and 692 controls, a cohort of 159 Hispanic patients and 137 controls, and a cohort of 176 black SSc patients and 194 controls). Genotyping was performed using a TaqMan 5' allelic discrimination assay.

RESULTS

In the British, Italian, and American white cohorts we observed an association of the FAS -670G allele with limited cutaneous SSc (lcSSc) (odds ratios [ORs] 1.25, 1.43, and 1.18, respectively). A meta-analysis comprising all 9 cohorts revealed an association of both the FAS -670G allele (OR 1.10) and the FAS -670GG genotype (OR 1.13) with the lcSSc phenotype. In a meta-analysis including only white subjects, both the FAS -670G allele and the FAS -670GG genotype remained associated with lcSSc (allele OR 1.12; genotype OR 1.16). In addition, a recessive model of the -670GG genotype exhibited a strong association with SSc, lcSSc, and anticentromere antibody-positive lcSSc (OR 1.23, OR 1.33, and OR 1.45, respectively).

CONCLUSION

Our data show that the FAS -670A>G polymorphism plays a role in lcSSc susceptibility. A similar trend has been observed in other autoimmune diseases.

Association study of ghrelin receptor gene polymorphisms in rheumatoid arthritis

OBJECTIVES

Ghrelin is a newly characterised growth hormone (GH) releasing peptide widely distributed that may play an important role in the regulation of metabolic balance in inflammatory diseases such as rheumatoid arthritis (RA) by decreasing the pro-inflammatory Th1 responses. In this study we investigated the possible contribution of several polymorphisms in the functional Ghrelin receptor to RA susceptibility.

METHODS

A screening of 3 single nucleotide polymorphisms (SNPs) was performed in a total of 950 RA patients and 990 healthy controls of Spanish Caucasian origin. Genotyping of all 3 SNPs was performed by real-time polymerase chain reaction technology, using the TaqMan 5'-allele discrimination assay.

RESULTS

We observed no statistically significant deviation between RA patients and controls for the GHSR SNPs analysed. In addition, we performed a haplotype analysis that did not reveal an association with RA susceptibility. The stratification analysis for the presence of shared epitope (SE), rheumatoid factor (RF) or antibodies anti cyclic citrullinated peptide (anti-CCP) did not detect significant association of the GHSR polymorphisms with RA.

CONCLUSIONS

These findings suggest that the GHSR gene polymorphisms do not appear to play a major role in RA genetic predisposition in our population.

BANK1 functional variants are associated with susceptibility to diffuse systemic sclerosis in Caucasians

OBJECTIVE

To investigate the possible association of the BANK1 gene with genetic susceptibility to systemic sclerosis (SSc) and its subphenotypes.

METHODS

A large multicentre case-control association study including 2380 patients with SSc and 3270 healthy controls from six independent case-control sets of Caucasian ancestry (American, Spanish, Dutch, German, Swedish and Italian) was conducted. Three putative functional BANK1 polymorphisms (rs17266594 T/C, rs10516487 G/A, rs3733197 G/A) were selected as genetic markers and genotyped by Taqman 5 allelic discrimination assay.

RESULTS

A significant association of the rs10516487 G and rs17266594 T alleles with SSc susceptibility was observed (pooled OR=1.12, 95% CI 1.03 to 1.22; p=0.01 and pooled OR=1.14, 95% CI 1.05 to 1.25; p=0.003, respectively), whereas the rs3733197 genetic variant showed no statistically significant deviation. Stratification for cutaneous SSc phenotype showed that the BANK1 rs10516487 G, rs17266594 T and rs3733197 G alleles were strongly associated with susceptibility to diffuse SSc (dcSSc) (pooled OR=1.20, 95% CI 1.05 to 1.37, p=0.005; pooled OR=1.23, 95% CI 1.08 to 1.41, p=0.001; pooled OR=1.15, 95% CI 1.02 to 1.31, p=0.02, respectively). Similarly, stratification for specific SSc autoantibodies showed that the association of BANK1 rs10516487, rs17266594 and rs3733197 polymorphisms was restricted to the subgroup of patients carrying anti-topoisomerase I antibodies (pooled OR=1.20, 95% CI 1.02 to 1.41, p=0.03; pooled OR=1.24, 95% CI 1.05 to 1.46, p=0.01; pooled OR=1.26, 95% CI 1.07 to 1.47, p=0.004, respectively).

CONCLUSION

The results suggest that the BANK1 gene confers susceptibility to SSc in general, and specifically to the dcSSc and anti-topoisomerase I antibody subsets.

The STAT4 gene influences the genetic predisposition to systemic sclerosis phenotype

The aim of this study was to investigate the possible role of STAT4 gene in the genetic predisposition to systemic sclerosis (SSc) susceptibility or clinical phenotype. A total of 1317 SSc patients [896 with limited cutaneous SSc (lcSSc) and 421 with diffuse cutaneous SSc (dcSSc)] and 3113 healthy controls, from an initial case-control set of Spanish Caucasian ancestry and five independent cohorts of European ancestry (The Netherlands, Germany, Sweden, Italy and USA), were included in the study. The rs7574865 polymorphism was selected as STAT4 genetic marker. We observed that the rs7574865 T allele was significantly associated with susceptibility to lcSSc in the Spanish population [P = 1.9 x 10(-5) odds ratio (OR) 1.61 95% confidence intervals (CI) 1.29-1.99], but not with dcSSc (P = 0.41 OR 0.84 95% CI 0.59-1.21). Additionally, a dosage effect was observed showing individuals with rs7574865 TT genotype higher risk for lcSSc (OR 3.34, P = 1.02 x 10(-7) 95% CI 2.11-5.31). The association of the rs7574865 T allele with lcSSc was confirmed in all the replication cohorts with different effect sizes (OR ranging between 1.15 and 1.86), as well as the lack of association of STAT4 with dcSSc. A meta-analysis to test the overall effect of the rs7574865 polymorphism showed a strong risk effect of the T allele for lcSSc susceptibility (pooled OR 1.54 95% CI 1.36-1.74; P < 0.0001). Our data show a strong and reproducible association of the STAT4 gene with the genetic predisposition to lcSSc suggesting that this gene seems to be one of the genetic markers influencing SSc phenotype.

A large multicentre analysis of CTGF -945 promoter polymorphism does not confirm association with systemic sclerosis susceptibility or phenotype

OBJECTIVE

To conduct a replication study to investigate whether the -945 CTGF genetic variant is associated with systemic sclerosis (SSc) susceptibility or specific SSc phenotype.

METHODS

The study population comprised 1180 patients with SSc and 1784 healthy controls from seven independent case-control sets of European ancestry (Spanish, French, Dutch, German, British, Swedish and North American). The -945 CTGF genetic variant was genotyped using a Taqman 5' allelic discrimination assay.

RESULTS

An independent association study showed in all the case-control cohorts no association of the CTGF -945 polymorphism with SSc susceptibility. These findings were confirmed by a meta-analysis giving a pooled OR = 1.12 (95% CI 0.99 to 1.25), p = 0.06. Investigation of the possible contribution of the -945 CTGF genetic variant to SSc phenotype showed that stratification according to SSc subtypes (limited or diffuse), selective autoantibodies (anti-topoisomerase I or anticentromere) or pulmonary involvement reached no statistically significant skewing.

CONCLUSION

The results do not confirm previous findings and suggest that the CTGF -945 promoter polymorphism does not play a major role in SSc susceptibility or clinical phenotype.

The interleukin 23 receptor gene does not confer risk to systemic sclerosis and is not associated with systemic sclerosis disease phenotype

Objectives:

Multiple studies indicate the role of the interleukin (IL)-17/IL-23 axis in autoimmune diseases, including systemic sclerosis (SSc). The aim of the current study was to investigate the possible implication of the IL23R gene in SSc susceptibility and/or clinical phenotype.

Methods:

An initial case–control study in 143 Dutch patients with SSc and geographically matched healthy individuals (n = 246) was carried out and followed by a replication study in a cohort of 365 Spanish patients with SSc and 515 healthy individuals. Seven single nucleotide polymorphisms (SNPs) spanning the IL23R gene were selected and genotyped using a Taqman assay.

Results:

Using a Dutch cohort of patients with SSc and controls we observed an association between two (rs11209032, rs1495965) of the seven tested SNPs and disease susceptibility (allelic p values: p = 0.02 and p = 0.01 respectively). However, a replication study in an independent Spanish cohort did not confirm these findings and reveal no association of any of the IL23R-tested SNP with disease susceptibility or clinical phenotype. Similarly, a meta-analysis considering both populations did not reveal any significant association. In addition, no association was observed between IL23R genetic variants and SSc clinical phenotypes.

Conclusions:

Our results suggest that the IL23R gene is not associated with SSc susceptibility or clinical phenotype.

Investigation of CD69 as a new candidate gene for rheumatoid arthritis

The aim of this study was to investigate the CD69 gene as a new functional candidate gene for rheumatoid arthritis (RA) genetic predisposition. A case-control association study including 933 RA patients and 800 healthy individuals was conducted. Five haplotype-tagging single nucleotide polymorphisms (SNPs) (rs929615, rs3176806, rs4763299, rs11052877, and rs3176789) covering the CD69 gene coding, 5' and 3' untranslated regions were selected as CD69 genetic markers and genotyped using a Taqman 5' allelic discrimination assay. No statistically significant differences were observed in the single marker association study with regard to either genotypic or allelic frequencies when considering the rs929615, rs3176806, rs4763299, rs11052877, and rs3176789 CD69 SNPs independently. According to these findings, no statistically significant skewing was observed between the RA patients and the controls in the distribution of CD69 haplotypes. In summary, our results do not support a major role for the CD69 gene polymorphisms in RA genetic predisposition in our population.

The IL23R Arg381Gln non-synonymous polymorphism confers susceptibility to ankylosing spondylitis

OBJECTIVES

Recent results have shown that the IL23R gene, coding for a subunit of the interleukin-23 receptor, is strongly associated with autoimmunity. The aim of the current study was to investigate, for the first time, the possible involvement of the IL23R gene in genetic susceptibility to ankylosing spondylitis (AS).

METHODS

We carried out a case-control association study in which 365 patients with AS and 500 blood bank donors were included. Eight single nucleotide polymorphisms (SNPs) spanning the IL23R gene were selected as genetic markers for our association study and were genotyped using a Taqman 5' allelic discrimination assay.

RESULTS

Interestingly, we observed association of two of eight IL23R genotyped SNPs. The strongest effect was conferred by the non-synonymous rs11209026 (Arg381Gln) SNP (odds ratio 0.46 95% confidence interval 0.2 to 0.7 p = 0.001). Similarly, the IL23R rs1343151 SNP showed association with AS genetic susceptibility (odds ratio 0.68 95% confidence interval 0.55 to 0.83 p = 0.0002). After a conditional case-control test we observed that the effect of these two genetic variants was independent of linkage disequilibrium.

CONCLUSIONS

These results suggest that the IL23R gene seems to be involved in AS genetic predisposition.

Analysis of interleukin-23 receptor (IL23R) gene polymorphisms in systemic lupus erythematosus

The aim of this study was to evaluate the association between systemic lupus erythematosus (SLE) and polymorphisms in the interleukin-23 receptor (IL23R) gene, which have been previously found to be associated with two autoimmune diseases: inflammatory bowel disease and psoriasis. Our study includes 224 SLE patients and 342 healthy controls. The genotyping of IL23R variants was carried out using a polymerase chain reaction system with predeveloped TaqMan allelic discrimination assays. No statistically significant differences were observed between SLE patients and healthy controls with any of the IL23R genetic variants. In addition, we did not find any significant differences when we stratified SLE patients according to their clinical and demographic features. These results suggest that IL23R polymorphisms do not appear to play an important role in the susceptibility or severity of SLE in the Spanish population.

Involvement of macrophage migration inhibitory factor gene in celiac disease susceptibility

The MIF gene has been associated with several diseases with inflammatory and autoimmune background, such as ulcerative colitis, rheumatoid arthritis and systemic lupus erythematosus. We aimed at testing the influence of two functional MIF promoter variants in celiac disease (CD) susceptibility. A (CAAT)(5-8) tetranucleotide repeat at position -794 and a single-nucleotide polymorphism at -173G/C were analyzed in the Spanish population (531 patients and 887 healthy controls). chi(2) statistics or Fisher exact test were used for comparisons. The -173C allele significantly increased risk ((CC+GC) vs GG: odds ratio (OR) (95% confidence interval (CI))=1.41 (1.10-1.81); P=0.005), as did carriage of the (CAAT)(7) allele (OR (95% CI)=1.36 (1.02-1.82); P=0.03) and of the haplotype (CAAT)(7)//-173C (OR (95% CI)=1.33 (1.00-1.76); P=0.04). Our data evidence for first time the role of the MIF gene increasing predisposition to CD. A common effect of MIF variants seems to underlie the etiology of these complex conditions.

Genetic basis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a clinically heterogeneous condition with a complex aetiology in which environmental and genetic factors are implicated. The contribution of human leukocyte antigen (HLA) genes, particularly the HLA-DRB1 gene, to RA genetic predisposition was the first described, and remains as the best characterised single genetic risk factor contributing to RA. However, it has been estimated that only 30% of the genetic contribution to RA can be attributed to HLA genes and it is suggested that other non-HLA genes may play a relevant role in RA susceptibility. Linkage studies and association studies are the two main strategies used in the investigation of genetic factors contributing to complex genetic traits. In this work we review the progress made in the field of RA genetics, focusing mainly on the contribution of candidate gene association studies to the dissection of RA genetic risk factors.

Contribution of MHC class I region to genetic susceptibility for giant cell arteritis

OBJECTIVE

The aim of this study was to assess the potential contribution of HLA-class I MICA and HLA-B gene polymorphisms towards the pathogenesis of giant cell arteritis (GCA).

METHODS

Ninety-eight biopsy-proven GCA patients and 225 ethnically matched controls from Lugo, Northwest Spain, were genotyped for the MICA-TM microsatellite polymorphism using a polymerase chain reaction (PCR)-based method. Genotyping of HLA-B was performed using PCR and detection with a reverse sequence-specific oligonucleotide (SSO) probes system.

RESULTS

A significant difference in the distribution of the alleles of MICA between patient and control groups (P = 0.005) was found. This was due to an increased frequency of the MICA A5 allele in GCA patients compared with controls (26 vs 13.6%; P = 0.0001; P(C) = 0.0005; OR 2.2, 95% CI 1.4-3.4). In addition, the HLA-B*15 allele showed a higher frequency in GCA patients compared with controls (P = 0.004; P(C) = 0.04; OR 2.7, 95% CI 1.3-5.7). Interestingly, the association observed with the MICA A5 allele seems to be independent of linkage disequilibrium with HLA-B, as well as independent of that previously described with HLA-DRB1*04. Remarkably, simultaneous presence of MICA A5 and HLA-B*15 or HLA-DRB1*04 genetic markers leads to an increase in the OR obtained for each individual genetic marker (MICA A5 + B*15 OR 3.2; MICA A5 + DRB1*04 OR 5.8).

CONCLUSIONS

Our results provide the first evidence that the MICA and HLA-B genes are independently associated with the genetic susceptibility to GCA, and suggest that several genes within the MHC might have independent effects in the susceptibility to this systemic vasculitis.

A functional variant in the CD209 promoter is associated with DQ2-negative celiac disease in the Spanish population

AIM: To address the role of CD209 in celiac disease (CD) patients. Non-human leukocyte antigen (HLA) genetic factors in CD predisposition are poorly understood, and environmental factors like infectious pathogens may play a role. CD209 is a dendritic and macrophage surface molecule involved in pathogen recognition and immune activation. Recently, a functional variant in the promoter of the CD209 gene (-336A/G) has been shown to affect the transcriptional CD209 activity in vitro and it has been associated with a higher susceptibility to/or severity of infection.

METHODS: The study population was composed of two case-control cohorts of 103 and 386 CD patients and 312 y 419 healthy controls as well as a panel of 257 celiac families. Genotyping for the -336A/G CD209 promoter polymorphism was performed using a TaqMan 5´ allelic discrimination assay. HLA-DQ was determined by hybridization with allele specific probes.

RESULTS: Initially, the case-control and familial studies did not find any association of the -336 A/G CD209 genetic variant with CD susceptibility. However, the stratification by HLA-DQ2 did reveal a significant association of CD209 promoter polymorphism in the HLA-DQ2 (-) group (carrier A vs GG in DQ2 (-) vs DQ2 (+) patients (P = 0.026, OR = 3.71).

CONCLUSION: The -336G CD209 allele seems to be involved in CD susceptibility in HLA-DQ2 (-) patients. Our results might suggest a possible role of pathogens in the onset of a minor group of CD patients.

CTLA4/CT60 polymorphism is not relevant in susceptibility to autoimmune inflammatory intestinal disorders

The aim of this work was to investigate the possible influence of the recently described CT60 A/G dimorphism of the CTLA4 (cytotoxic T-lymphocyte antigen 4) gene in the susceptibility to two different autoimmune inflammatory intestinal disorders, inflammatory bowel disease (IBD) and celiac disease. We analyzed a case-control cohort composed of 528 Spanish patients with IBD (284 with Crohn disease and 244 with ulcerative colitis) and 454 unrelated healthy individuals, and additionally a group of 90 celiac disease families. CT60 genotyping was performed with a TaqMan 5' allelic discrimination assay. After comparing patients with IBD with the control population, we found no significant deviation in the distribution of the alleles or genotypes of CTLA4/CT60 dimorphism. In addition, by means of familial and case-control analysis, no evidence for a statistically significant association was observed between CTLA4/CT60 and celiac disease susceptibility. Therefore, our results suggest that the CTLA4/CT60 polymorphism does not play a major role in inflammatory intestinal disorders.

Association study of functional genetic variants of innate immunity related genes in celiac disease

Background

Recent evidence suggest that the innate immune system is implicated in the early events of celiac disease (CD) pathogenesis. In this work for the first time we have assessed the relevance of different proinflammatory mediators typically related to innate immunity in CD predisposition.

Methods

We performed a familial study in which 105 celiac families characterized by the presence of an affected child with CD were genotyped for functional polymorphisms located at regulatory regions of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes. Familial data was analysed with a transmission disequilibrium test (TDT) that revealed no statistically significant differences in the transmission pattern of the different genetic markers considered.

Results

The TDT analysis for IL-1α, IL-1β, IL-1RN, IL-18, and MCP-1 genes genetic variants did not reveal biased transmission to the affected offspring. Only a borderline association of RANTES promoter genetic variants with CD predisposition was observed.

Conclusion

Our results suggest that the analysed polymorphisms of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes do not seem to play a major role in CD genetic predisposition in our population.

Poly (ADP-ribose) polymerase-1 haplotypes are associated with coeliac disease

In coeliac disease (CD) there is an inflammatory status of the intestinal mucosa because of a high expression of proinflammatory mediators. The nuclear protein poly (ADP-ribose) polymerase-1 (PARP-1) has been implicated in the initial inflammatory response by modulating transcription of inflammation-related genes. The aim of this work was to investigate the role of PARP-1 gene promoter region haplotypes in relation to coeliac disease susceptibility. We analysed a coeliac population consisting of a case-control panel with 120 CD patients and 311 healthy blood donors. A CA microsatellite, as haplotype-defining variant of the whole PARP-1 promoter, was typed using a polymerase chain reaction (PCR) method combined with fluorescence technology. We considered two promoter haplotypes: A defined by short CA alleles (83-87 bp) and B defined by long CA alleles (89-101 bp). Haplotype A was significantly increased within the coeliac patients group (P = 0.007 OR 1.6 95%CI 1.12-2.35). Additionally, we observed a significant dose effect, showing homozygous individuals for haplotype A higher risk for CD susceptibility (P = 0.007, OR 1.79 95%CI 1.14-2.82). Our results provide the first evidence that PARP-1 haplotypes are related with coeliac disease susceptibility.

Interleukin-18-promoter polymorphisms are not relevant in rheumatoid arthritis

Interleukin-18 (IL-18), a member of the IL-1 family, is known to play a relevant role in rheumatoid arthritis (RA) physiopathology mainly by promoting the inflammatory response. The aim of this work was to investigate the possible implication of two single-nucleotide polymorphisms (SNPs) [-607 A/C (rs1946518) and -137 G/C (rs187238)] within the IL-18-promoter region in RA predisposition and clinical course. A total of 362 unrelated RA patients and 339 healthy controls were genotyped using a real-time polymerase chain reaction (PCR) method for the -607 A/C SNP and a sequence-specific PCR method (PCR-SSP) for the -137 G/C polymorphism. No statistically significant differences were observed for both -607 and -137 IL-18-promoter polymorphisms between RA patients and controls, considering either allelic or genotypic frequencies. In addition, no association was found with the haplotypes inferred by the two polymorphisms and RA susceptibility. This was also the case when RA patients were stratified according to sex, age at the onset of the disease, rheumatoid factor status, and extraarticular manifestations. Our data suggest that -607 A/C (rs1946518) and -137 G/C (rs187238) polymorphisms within the IL-18-promoter region do not play a major role in RA predisposition.

A functional variant of IFNγ gene is associated with coeliac disease

In coeliac disease (CD) a profile of proinflammatory cytokines are secreted interferon gamma (IFNgamma) being one of the most important. A dinucleotide polymorphism consisting of a variable number of CA repeats related with IFNgamma production levels, has been reported on the first intron of the IFNgamma gene. The aim of this study was to analyse the influence of the functional IFNgamma CA repeats in CD predisposition through familial and case-control studies. The familial analysis showed that the 124 bp allele was significantly more transmitted to the affected offspring (P=0.02), while the 126 bp allele showed a statistically significant nontransmission pattern (P=0.01). Nevertheless, in the case-control analysis, we could not find a direct association of CA repeats with CD. This fact might be due to parent-of-origin effect in the IFNgamma CA polymorphism. Our data suggest a possible role of IFNgamma CA polymorphism in CD susceptibility.

CA microsatellite polymorphism of the nuclear factor kappa B1 gene in celiac disease

In the present work, we investigate the possible effect of a CAn microsatellite polymorphism in the nuclear factor kappa B1 (NFKB1) gene on predisposition to celiac disease (CD). Seventy-eight Spanish families with CD were genotyped using a polymerase chain reaction (PCR)-fluorescent method, and the transmission patterns of different CAn alleles were analysed. Furthermore, in order to type the CAn polymorphism more accurately, samples between 126 and 144 bp were cloned and sequenced. A trend of association with the 132-bp allele was found (P = 0.02). This allele was more frequently transmitted to affected sibs, although the results of statistical tests were not significant after correction for multiple comparisons. After sequencing, we found that the 132-, 138- and 142-bp alleles had two As at the end of the CA microsatellite, with the other alleles presenting the described pattern (NCB1 nucleotide U60337) for the microsatellite repeats. These results suggest that the NFKB1 CAn microsatellite does not play a major role in CD susceptibility. In addition, a more detailed molecular characterization of the CA microsatellite is described.

Association of MICA-A5.1 allele with susceptibility to celiac disease in a family study

OBJECTIVE

The aim of this study was to analyze the role of the major histocompatibility complex class I chain-related gene A (MICA) transmembrane polymorphism in celiac disease (CD) susceptibility.

METHODS

Sixty-one celiac Spanish families were genotyped for MICA transmembrane polymorphism by a polymerase chain reaction method combined with fluorescent technology. A transmission disequilibrium test was performed to investigate the preferential transmission of MICA alleles to the affected offspring.

RESULTS

The MICA A5.1 allele was shown to be significantly transmitted to the affected siblings. This association was independent of the CD-predisposing DQ2 haplotype. Additionally, we classified our celiac families into typical and atypical groups as we found a significant association with MICA A5.1 in typical celiac families. There was also an association tendency with atypical families.

CONCLUSIONS

Our data suggest that the MICA A5.1 allele is associated with CD development independently of DQ2-extended haplotype and clinical forms of CD.

A new allele within the transmembrane region of the human MICA gene with seven GCT repeats

Major histocompatibility complex class I chain-related genes (MIC) belong to a multicopy gene family located within the HLA class I region of chromosome 6. They encode for proteins that have a completely different organization, expression, and products from classical HLA class I gene products. One member of this family is the MICA gene, which is characterized by its high degree of polymorphism, with over 50 MICA alleles described. Moreover, MICA exon 5 presents a microsatellite polymorphism consisting of a variable number of GCT repeats that encode for 4, 5, 6, 9, or 10 alanine residues, and a variant (MICA A5.1) that includes a nucleotide insertion (GCT-->GGCT). In this study, we report a novel allele in the transmembrane region of the MICA gene consisting of seven GCT repeats found in a family based study of MICA polymorphism in celiac disease.

Mycelial differentiation and spore formation by Streptomyces brasiliensis in submerged culture

Streptomyces brasiliensis ATCC 23727 showed extensive sporulation when cultured in a liquid medium containing galactose and glutamic acid as carbon and nitrogen sources. Sporogenic hyphae formed under these conditions were morphologically similar and developmentally equivalent to aerial hyphae and metamorphosed into chains of spores by following a sequence of ultrastructural changes similar to that observed during growth on solid media. In addition, our electron microscopy study revealed two previously unrecognized aspects of hyphal development in streptomycetes: the formation of sporogenic hyphae was always preceded by changes in the structure of the nucleoid, and the sheath that characteristically covered these hyphae was not deposited coincidently with wall formation in the apical growing portion of the hypha.

Changes in glycogen and trehalose content of Streptomyces brasiliensis hyphae during growth in liquid cultures under sporulating and non-sporulating conditions

Streptomyces brasiliensis ATCC 23727 showed extensive sporulation when cultured in a liquid medium containing galactose and glutamic acid as carbon and nitrogen sources. Under such conditions, glycogen and trehalose are accumulated in the hyphae coinciding with spore formation. The results reported here suggest that glycogen accumulated in sporogenic hyphae is converted into trehalose during the final period of spore maturation. Glycogen is also accumulated in the hyphae when S. brasiliensis is cultured under conditions which did not support sporulation. Under such conditions, however, glycogen degradation is not accompanied by accumulation of trehalose. This suggest that the conversion of glycogen into trehalose might be a sporulation-specific event in streptomycetes.

Characterization and regulation of type A endothelin receptor gene expression in bovine luteal cell types

Our previous studies demonstrated that endothelin-1 (ET-1), a 21-amino acid vasoconstrictor peptide, has a paracrine regulatory role in bovine corpus luteum (CL). The peptide is produced within the gland where it inhibits progesterone production by acting via the selective type A endothelin (ETA) receptors. The present study was designed to characterize ETA receptor gene expression in different ovarian cell types and its hormonal regulation. ETA receptor messenger RNA (mRNA) levels were high in follicular cells as well as in CL during luteal regression. At this latter stage, high ETA receptor expression concurred with low prostaglandin F2alpha receptor mRNA. The ETA receptor gene was expressed by all three major cell populations of the bovine CL; i.e. small and large luteal cells, as well as in luteal endothelial cells. Among these various cell populations, the highest ETA receptor mRNA levels were found in endothelial cells. cAMP elevating agents, forskolin and LH, suppressed ETA receptor mRNA expression in luteinized theca cells (LTC). This inhibition was dose dependent and was evident already after 24 h of incubation. In luteinized granulosa cells (LGC), 10 and 100 ng/ml of insulin-like growth factor I and insulin (only at a concentration of 2000 ng/ml) markedly decreased ETA receptor mRNA levels. In both LGC and LTC there was an inverse relationship between ETA receptor gene expression and progesterone production; insulin (in LGC) and forskolin (in LTC) enhanced progesterone production while inhibiting ETA receptor mRNA levels. Our findings may therefore suggest that, during early stages of luteinization when peak levels of both LH and insulin-like growth factor I exist, the expression of ETA receptors in the gland are suppressed. This study demonstrates physiologically relevant regulatory mechanisms controlling ETA receptor gene expression and further supports the inhibitory role of ET-1 in CL function.