Myristoylation Confers Oral Bioavailability and Improves the Bioactivity of c(MyD 4-4), a Cyclic Peptide Inhibitor of MyD88

Myeloid differentiation primary response 88 (MyD88) is an intracellular adaptor protein central to the signaling of multiple receptors involved in inflammation. Since innate immune inflammation promotes autoimmunity, MyD88 is an attractive target in autoimmune disease. We previously developed c(MyD 4-4), a novel cyclic peptide competitive inhibitor of MyD88 dimerization that is metabolically stable. Parenteral administration of c(MyD 4-4) reduces disease severity in a mouse model of the human autoimmune disease multiple sclerosis. We now show that N-terminal myristoylation of c(MyD 4-4) enhances the competitive inhibition of MyD88 dimerization in living cells, leading to improved inhibition of the Toll-like receptor and IL-1 receptor signaling. Importantly, myristoylation converts c(MyD 4-4) to an orally bioavailable inhibitor of MyD88. Oral administration of c(MyD 4-4) significantly lowered the inflammatory cytokines secreted by peripheral autoimmune T cells in mice immunized with myelin antigens and ameliorated disease severity in the mouse model of multiple sclerosis. Taken together, we show the conversion of a protein active region to a metabolically stable, selective cyclic peptide that is orally bioavailable.

Epithelial cells detect functional type III secretion system of enteropathogenic Escherichia coli through a novel NF-κB signaling pathway

Enteropathogenic Escherichia coli (EPEC), a common cause of infant diarrhea, is associated with high risk of mortality in developing countries. The primary niche of infecting EPEC is the apical surface of intestinal epithelial cells. EPEC employs a type three secretion system (TTSS) to inject the host cells with dozens of effector proteins, which facilitate attachment to these cells and successful colonization. Here we show that EPEC elicit strong NF-κB activation in infected host cells. Furthermore, the data indicate that active, pore-forming TTSS per se is necessary and sufficient for this NF-κB activation, regardless of any specific effector or protein translocation. Importantly, upon infection with wild type EPEC this NF-κB activation is antagonized by anti-NF-κB effectors, including NleB, NleC and NleE. Accordingly, this NF-κB activation is evident only in cells infected with EPEC mutants deleted of nleB, nleC, and nleE. The TTSS-dependent NF-κB activation involves a unique pathway, which is independent of TLRs and Nod1/2 and converges with other pathways at the level of TAK1 activation. Taken together, our results imply that epithelial cells have the capacity to sense the EPEC TTSS and activate NF-κB in response. Notably, EPEC antagonizes this capacity by delivering anti-NF-κB effectors into the infected cells.

The intestine harbors a dense community of commensal bacteria that play a vital role in host health and homeostasis, but it is also the port of entry for many pathogens. An important function of the intestinal epithelial cells is coordinating the immune response to microbial signals, ranging from tolerance towards beneficial species to a robust anti-pathogen immune response. The mechanisms underlying the ability of intestinal epithelial cells to specifically distinguish pathogens from commensal bacteria are only partially understood. Commensal and enteropathogenic E. coli strains are highly similar and both reside in the gut lumen. However, only the pathogen is equipped with a type III protein secretion system, which is employed to inject effector proteins into the host cells. Here we show that epithelial cells distinguish the pathogenic from the highly similar commensal E. coli strains through specific sensing of the TTSS activity and respond by triggering a novel defense signaling pathway, but the pathogen attempt to avoid its detection by injection effectors that block the defense signaling.

Inhibition of Myeloid Differentiation Factor 88 Reduces Human and Mouse T-Cell Interleukin-17 and IFNγ Production and Ameliorates Experimental Autoimmune Encephalomyelitis Induced in Mice

Myeloid differentiation factor 88 (MyD88) recruits signaling proteins to the intracellular domain of receptors belonging to the toll-like/interleukin-1 (IL-1) receptor superfamily. Mice lacking MyD88 are highly susceptible to infectious diseases, but tend to resist experimentally induced autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE) and manifest diminished allograft rejection. We reasoned that inhibition of MyD88 should influence the cytokine profile of responding T cells by blocking costimulatory molecule expression by antigen-presenting cells (APCs) and by inhibiting T-cell responses to IL-18. We now report that inhibition of MyD88 in human APCs led to decreased IFNγ and IL-17 production and a shift to IL-4 production by responding T cells in a mixed lymphocyte reaction. Direct inhibition of Myd88 in mouse and human T cells also reduced their production of IFNγ in response to IL-12/IL-18 stimulation. Finally, systemic MyD88 antagonism significantly reduced the clinical manifestations of EAE in mice. Thus, MyD88 appears to be a key factor in determining T cell phenotype and represents a potential target for therapeutic intervention.

Double heterozygosity in the BRCA1 and BRCA2 genes in the Jewish population

BACKGROUND

The frequency and characteristics of disease in individuals who concomitantly harbor pathogenic mutations in both BRCA1 and BRCA2 genes are not established.

MATERIALS AND METHODS

Data were collected from the database of Clalit Health Services National Familial Cancer Consultation Service. Probands referred to this clinical service and their family members are routinely tested for the three Jewish founder mutations (BRCA1: 185delAG, 5382insC, BRCA2: 6174delT). In addition, carriers identified in a population-based cohort of all cases diagnosed with breast cancer in Israel in 1987-1988 allowed the estimation of the population frequency of this phenomenon.

RESULTS

In the clinic-based series of 1191 carriers of mutations in BRCA1 or BRCA2 belonging to 567 families, 22 males and females (1.85%) from 17 different families (3.0%) were found to harbor two different mutations. These included 18 individuals (1.51%) who concomitantly carried the 185delAG BRCA1 and the 6174delT BRCA2 mutations and four individuals (0.34%) who carried the 5382insC BRCA1 and the 6174delT mutations. All individuals were heterozygote carriers and none had a double mutation of both founder mutations in the BRCA1 gene itself. Seven of the 16 double carrier women (46.7%) had a personal history of breast carcinoma, diagnosed at a mean age of 44.6, compared with 372/926 (40.2%) carriers of a single mutation diagnosed with a mean age at diagnosis of 48.1 [odds ratio (OR)=1.3, 95% confidence interval (CI) 0.4-4.0]. One case (6.7%) had a personal history of ovarian carcinoma diagnosed at the age of 53 compared with 55/926 (5.9%) of the women with single mutation (OR=1.1, CI=0.2-7.6). The frequency of double mutations in the population-based national breast cancer cohort was 2.2% of all carriers, and 0.3% of all breast cancer cases in the Ashkenazi population in the cohort. The mean age at diagnosis of breast cancer was younger in the carriers of two mutations.

CONCLUSION

Double carriers of mutations in the BRCA genes are rare and seem to be carrying a similar probability of developing breast and ovarian cancers as carriers of single mutations.

Expression of serum amyloid a in human ovarian epithelial tumors: implication for a role in ovarian tumorigenesis

Serum amyloid A (SAA) is an acute phase protein which is expressed primarily in the liver as a part of the systemic response to various injuries and inflammatory stimuli; its expression in ovarian tumors has not been described. Here, we investigated the expression of SAA in human benign and malignant ovarian epithelial tumors. Non-radioactive in situ hybridization applied on ovarian paraffin tissue sections revealed mostly negative SAA mRNA expression in normal surface epithelium. Expression was increased gradually as epithelial cells progressed through benign and borderline adenomas to primary and metastatic adenocarcinomas. Similar expression pattern of the SAA protein was observed by immunohistochemical staining. RT-PCR analysis confirmed the overexpression of the SAA1 and SAA4 genes in ovarian carcinomas compared with normal ovarian tissues. In addition, strong expression of SAA mRNA and protein was found in the ovarian carcinoma cell line OVCAR-3. Finally, patients with ovarian carcinoma had high SAA serum levels, which strongly correlated with high levels of CA-125 and C-reactive protein. Enhanced expression of SAA in ovarian carcinomas may play a role in ovarian tumorigenesis and may have therapeutic application.

The TP53 Arg72Pro and MDM2 309G>T polymorphisms are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers

Background:

The TP53 pathway, in which TP53 and its negative regulator MDM2 are the central elements, has an important role in carcinogenesis, particularly in BRCA1- and BRCA2-mediated carcinogenesis. A single nucleotide polymorphism (SNP) in the promoter region of MDM2 (309T>G, rs2279744) and a coding SNP of TP53 (Arg72Pro, rs1042522) have been shown to be of functional significance.

Methods:

To investigate whether these SNPs modify breast cancer risk for BRCA1 and BRCA2 mutation carriers, we pooled genotype data on the TP53 Arg72Pro SNP in 7011 mutation carriers and on the MDM2 309T>G SNP in 2222 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Data were analysed using a Cox proportional hazards model within a retrospective likelihood framework.

Results:

No association was found between these SNPs and breast cancer risk for BRCA1 (TP53: per-allele hazard ratio (HR)=1.01, 95% confidence interval (CI): 0.93–1.10, P_trend=0.77; MDM2: HR=0.96, 95%CI: 0.84–1.09, P_trend=0.54) or for BRCA2 mutation carriers (TP53: HR=0.99, 95%CI: 0.87–1.12, P_trend=0.83; MDM2: HR=0.98, 95%CI: 0.80–1.21, P_trend=0.88). We also evaluated the potential combined effects of both SNPs on breast cancer risk, however, none of their combined genotypes showed any evidence of association.

Conclusion:

There was no evidence that TP53 Arg72Pro or MDM2 309T>G, either singly or in combination, influence breast cancer risk in BRCA1 or BRCA2 mutation carriers.

BRCA1 breast cancer risk is modified by CYP19 polymorphisms in Ashkenazi Jews

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Background: The lack of full penetrance of mutations in the BRCA genes suggests the possible existence of other modifying genes and/or environmental factors. Exposure to sex hormones is an established major risk factor for breast cancer. The polymorphisms ( rs700518 (Val80), [TTTA]n) in CYP19, a gene encoding the estrogen synthesizing enzyme P450 aromatase, may be associated with risk of breast cancer in BRCA carriers and/or non-carriers. Methods: An analysis of 922 breast cancer cases and 901 healthy controls, including 408 BRCA carriers and 1,415 non-carriers was carried out. Cases and controls of Ashkenazi origin came from a population-based case-control study of breast cancer in Northern Israel, enriched with BRCA carriers (with and without cancer) from a clinical familial cancer service. DNA samples were genotyped for Ashkenazi BRCA1,2 mutations (185delAG, 5382insC, 6174delT) and CYP19 polymorphisms by allelic discrimination using 7900HT ABI sequence detection system. Statistical analyses were performed using SPSS, SAS, and R language. Results: The Val80 G/G genotype was associated with a significantly increased risk of breast cancer as compared to the A/A genotype in BRCA1 carriers (OR=2.2; 95%CI=1.04–4.53; p=0.039) but not in BRCA2 carriers (OR=0.45, 95%CI=0.17–1.16; p=0.098). A similar magnitude association, though not statistically significant, was found between the Val80 and ER-negative status of breast tumors. A reconstructed common haplotype composed of four haplotype-tagging SNPs in Haplotype Block 4, covering the CYP19 coding region, was also significantly associated with breast cancer risk in 210 carriers of BRCA1 (OR=3.4; 95%CI=1.5–7.8; p=0.004). No significant association between CYP19 polymorphisms and breast cancer risk was found in non-carriers. Conclusions: Our data suggest that the CYP19 Val80 polymorphism and a haplotype including this polymorphism are associated with increased breast cancer risk in BRCA1 carriers. As a higher number of repeats in intron 4 ([TTTA]n polymorphism) is found in complete linkage disequilibrium with the Val80 G allele and is associated with higher estrogen levels, this mechanism could explain the phenotypic uniqueness of the carriers.

No significant financial relationships to disclose.

Expression of serum amyloid A, in normal, dysplastic, and neoplastic human colonic mucosa: implication for a role in colonic tumorigenesis

Serum amyloid A (SAA) is an acute phase reactant, whose level in the blood is elevated in response to trauma, infection, inflammation, and neoplasia. Elevated levels of SAA in the serum of cancer patients were suggested to be of liver origin rather than a tumor cell product. The role of SAA in human malignancies has not been elucidated. We investigated the expression of SAA at various stages of human colon carcinoma progression. Nonradioactive in situ hybridization applied on paraffin tissue sections from 26 colon cancer patients revealed barely detected SAA mRNA expression in normal looking colonic epithelium. Expression was increased gradually as epithelial cells progressed through dysplasia to neoplasia. Deeply invading colon carcinoma cells showed the highest levels of SAA. Expression was also found in colon carcinoma metastases. Cells of lymphoid follicles of the intestinal wall, inflammatory cells, ganglion cells, and endothelial cells, also expressed SAA mRNA. Immunohistochemical staining revealed SAA protein expression that colocalized with SAA mRNA expression. RT-PCR analysis confirmed the expression of the SAA1 and SAA4 genes in colon carcinomas, expression that was barely detectable in normal colon tissues. These findings indicate local and differential expression of SAA in human colon cancer tissues and suggest its role in colonic tumorigenesis.

Differences in the characteristics of families with BRCA1 and BRCA2 mutations in Israel

Three specific mutations in the BRCA1 (185delAG, 5382insC) and BRCA2 (6174delT) genes have been reported to be of high prevalence in the Jewish Ashkenazi population. We studied the differences in phenotype of families carrying these mutations. All consecutive families found by the CHS Familial Cancer Service to carry one of the three 'Jewish' mutations of the BRCA1/BRCA2 genes were evaluated for phenotypic characteristics. Chi-squared and Student's t-test statistics were employed to study differences in a variety of clinical and demographic parameters. A total of 111 families with 1499 family members were included. Among them 454 cases of cancer (297 in breast/ovary) were reported. Ovarian cancer, but not breast cancer, was detected at a significantly younger age among carriers of 185delT compared with other mutation carriers. In families with 185delAG, 5382insC and 6174delT mutations, breast cancer was found in 20.2, 39.4 and 24.1% of all identified women (born between 1900 and 1975), correspondingly. The corresponding figures for ovarian cancer were 13.9, 6.8 and 4.9%. Families carrying the 5382insC mutation had the highest probability of expressing bilateral breast cancer (38.9% of families, 15.4% of women with cancer, 6.1% of all women in family) and metachronous breast and ovary tumours (22.2, 9.8 and 4.5% correspondingly). Other tumours were reported in 7.9, 9.1 and 12.0% of women and 9.5, 12.9 and 15.8% of men in families with 185delAG, 5382insC, 6174delT, correspondingly. Marked phenotypic differences were found between families carrying different BRCA mutations warranting mutation-specific counselling to families seeking risk-reduction advice. 5382insC emerged as a most aggressive mutation.

Cancer Genetics Service Provision: A Comparison of Seven European Centres

OBJECTIVE

To conduct a survey in seven European cancer genetics centres to compare service provision, organisation and practices for familial breast and colon cancer consultations and testing. Information was obtained on aspects of services both nationally and locally.

METHODS

A detailed survey questionnaire was adapted collaboratively to obtain the required information. Initial survey data were collected within each centre and interim results were discussed at two European Workshops. Where differences in practice existed, details were clarified to ensure accuracy and adequacy of information. Participating centres were Haifa (Israel), Hannover (Germany), Leiden (The Netherlands), Leuven (Belgium), Manchester (UK), Marseille (France) and Milan (Italy), representing countries with populations ranging from 6.5 to 80 million.

RESULTS

The European countries diverged in regard to the number of cancer genetics centres nationally (from 8 in Belgium to 37 in France), and the average population served by each centre (from 0.59 million in Israel to 3.32 million in Italy). All centres offered free care at the point of access, but referral to specialist care varied according to national health care provision. At a centre level, staff roles varied due to differences in training and health care provision. The annual number of counsellees seen in each participating centre ranged from 200 to over 1,700. Access to breast surveillance or bowel screening varied between countries, again reflecting differences in medical care pathways. These countries converged in regard to the wide availability of professional bodies and published guidelines promoting aspects of service provision. Similarities between centres included provision of a multidisciplinary team, with access to psychological support, albeit with varying degrees of integration. All services were dominated (70-90%) by referrals from families with an increased risk of breast cancer despite wide variation in referral patterns. Collection of pedigree data and risk assessment strategies were broadly similar, and centres used comparable genetic testing protocols. Average consultation times ranged between 45 and 90 min. All centres had access to a laboratory offering DNA testing for breast and bowel cancer-predisposing genes, although testing rates varied, reflecting the stage of service development and the type of population. Israel offered the highest number of genetic tests for breast cancer susceptibility because of the existence of specific founder mutations, in part explaining why the cancer genetics service in Haifa differed most from the other six.

CONCLUSION

Despite considerable differences in service organisation, there were broad similarities in the provision of cancer genetic services in the centres surveyed.

[Hospital-at-home as a solution for the treatment requirements of acute exacerbation in multiple sclerosis]

Cooperation between the Multiple Sclerosis center at the Carmel medical center and the Hospital-at-Home (H.H) department of the continuing care unit in the Haifa and Western Galilee district of the Clalit Health Services has made it possible to give methylprednisolone intravenously to Multiple Sclerosis (M.S) patients during an acute exacerbation of the disease, in their home. In this study, we describe the joint work of the two centers. We have summarized 30 treatment courses given to 26 patients in their homes, following referral by the M.S. center, in the year 1999. The aims of the study included assessing satisfaction, safety and cost-effectiveness in a treatment course in the HH framework, as compared to the same treatment being conducted in the framework of hospitalization in various neurological departments, as was done in the past in the same group of patients. The expenses involved in HH for this group of patients were only 14% of the parallel treatment in the hospital (a savings of 86%). The treatment has proven to be extremely safe. There were no side-effects that required returning patients to the hospital, and the treatment was given in conditions of maximum comfort for the patient and his family. A telephone survey was conducted, which compared the satisfaction with the HH treatment, and the burden caused the patient's family to prior hospitalization for the same treatment. For all of the parameters examined, greater satisfaction was distinctly proven in the HH treatment. In light of these findings, we can conclude that giving methylprednisolone intravenously to M.S patients during an acute exacerbation, in the HH framework, is a safe and cost effective treatment, preferred by the patient and his family.

Proband family uptake of familial-genetic counselling

Familial-genetic counselling for breast/ovarian cancers is a process initiated by a proband, and designed for all her/his blood relatives. This study focused on family members' uptake of an invitation to participate in counselling as a function of proband and family determinants. Of 163 breast/ovarian syndrome families tested, 67 carrying one of the three known Jewish mutations were included. For both the proband and family members, demographic variables, cancer status, position in the family and type of referral (proband only) were examined. Eligible family members' uptake rate was 34%. Lower family uptake was associated with the proband having cancer, and/or being doctor-referred (vs self-referred). Individuals of either the proband's or older generations had lower uptake rates compared with family members of younger generations. Being a cancer patient or a first degree relative of either a cancer patient or the proband was related to higher uptake. The study results indicate that baseline information routinely gathered by counselling services can be useful in predicting uptake. Providing insight into complex barriers to genetic counselling, these results also suggest potential directions for interventions to improve uptake, thereby enhancing individuals' abilities to make informed decisions regarding issues such as genetic testing.