Dual roles of hemidesmosomal proteins in the pancreatic epithelium: the phosphoinositide 3-kinase decides

Given the failure of chemo- and biotherapies to fight advanced pancreatic cancer, one major challenge is to identify critical events that initiate invasion. One priming step in epithelia carcinogenesis is the disruption of epithelial cell anchorage to the basement membrane which can be provided by hemidesmosomes (HDs). However, the existence of HDs in pancreatic ductal epithelium and their role in carcinogenesis remain unexplored. HDs have been explored in normal and cancer pancreatic cells, and patient samples. Unique cancer cell models where HD assembly can be pharmacologically manipulated by somatostatin/sst2 signaling have been then used to investigate the role and molecular mechanisms of dynamic HD during pancreatic carcinogenesis. We surprisingly report the presence of mature type-1 HDs comprising the integrin α6β4 and bullous pemphigoid antigen BP180 in the human pancreatic ductal epithelium. Importantly, HDs are shown to disassemble during pancreatic carcinogenesis. HD breakdown requires phosphoinositide 3-kinase (PI3K)-dependent induction of the matrix-metalloprotease MMP-9, which cleaves BP180. Consequently, integrin α6β4 delocalizes to the cell-leading edges where it paradoxically promotes cell migration and invasion through S100A4 activation. As S100A4 in turn stimulates MMP-9 expression, a vicious cycle maintains BP180 cleavage. Inactivation of this PI3K-MMP-9-S100A4 signaling loop conversely blocks BP180 cleavage, induces HD reassembly and inhibits cell invasion. We conclude that mature type-1 HDs are critical anchoring structures for the pancreatic ductal epithelium whose disruption, upon PI3K activation during carcinogenesis, provokes pancreatic cancer cell migration and invasion.

Experimental evidence for superprism phenomena in SOI photonic crystals

A first experimental demonstration of a planar superprism in silicon microphotonics technology using silicon on insulator (SOI) substrates is presented. Experimental results for anomalous wavelengthdependent angular dispersion in SOI triangular lattice planar photonic crystals are reported. An angular swing of 14 degrees is measured for light propagating near the Gamma-K direction as the input wavelength is changed from 1295 nm to 1330 nm, which corresponds to an angular dispersion of 0.4 degrees /nm. For the Gamma-M direction, a negative wavelength dispersion has been recorded. An opposite sign angular deviation of 21 degrees is observed as the input wavelength is changed from 1316 nm to 1332 nm, i.e. a dispersion of 1.3 degrees /nm.

Low-loss submicrometer silicon-on-insulator rib waveguides and corner mirrors

Rib microwaveguides are demonstrated on silicon-on-insulator substrates with Si film thickness of either 380 or 200 nm and a width of 1 microm. Corner mirrors that allow compact 90 degrees turns between two perpendicular waveguides are characterized. Measured propagation losses are approximately 0.4 dB/cm and approximately 0.5 dB/cm for 380-nm and 200-nm Si film, respectively, and mirror losses are approximately 1 dB. This allows the development of applications such as optical interconnects in integrated circuits over propagation distances larger than several centimeters.

Rheumatoid arthritis susceptibility and interleukin 10: a study of two ethnically diverse populations

INTRODUCTION

IL-10 is an immunoregulatory cytokine which may modulate disease expression in rheumatoid arthritis (RA). The IL-10 gene is highly polymorphic with a number of single nucleotide polymorphisms in the promoter region and two microsatellite loci, IL10.R and IL10.G, 4 kb and 1.1 kb 5' of the transcription initiation site. It has been reported that allele 2 of the IL10.R microsatellite (IL10.R2) is associated with increased IL-10 secretion and IL10.R3 with reduced secretion. Subsequently, over-representation of IL10.R2 and under-representation of IL10.R3 in three independent RA groups has been reported. The aim of the current study is to determine whether there is an association between the IL10.R2 allele and RA in two ethnically distinct populations.

METHODS

IL10.R genotypes were determined by semi-automated DNA sequencing technology in 186 UK Caucasians and 138 South Africans of Zulu or Sotho origin, fulfilling the 1987 American College of Rheumatology (ACR) criteria for RA. The Caucasian patients had relatively severe disease and comprised 75 patients with RA vasculitis, 22 with Felty's syndrome and 89 who had undergone a joint replacement (hip or knee) within 15 years of the onset of disease. Allele frequencies were compared with 296 Caucasians and/or 73 South Africans.

RESULTS

The frequency of the IL10.R2 allele was significantly greater in the South Africans (RA and controls) than in the Caucasians (0.78 vs 0.66, P=1 x 10(-6)), while the frequency of IL10.R3 was less common (0.16 vs 0.3, P=1 x 10(-8)). No differences were observed in either IL10.R2 or IL10.R3 frequencies between patients and controls in either population.

CONCLUSIONS

We were unable to confirm any association between IL10.R alleles and RA in this study. However, significant differences were demonstrated in the frequency of IL10.R2 and IL10.R3 between the two ethnic groups. The relatively high frequency of IL10.R2 in the South African population (0.78) would have reduced the power to detect an association with RA.

Suggestive evidence for association of human chromosome 18q12-q21 and its orthologue on rat and mouse chromosome 18 with several autoimmune diseases

Some immune system disorders, such as type 1 diabetes, multiple sclerosis (MS), and rheumatoid arthritis (RA), share common features: the presence of autoantibodies and self-reactive T-cells, and a genetic association with the major histocompatibility complex. We have previously published evidence, from 1,708 families, for linkage and association of a haplotype of three markers in the D18S487 region of chromosome 18q21 with type 1 diabetes. Here, the three markers were typed in an independent set of 627 families and, although there was evidence for linkage (maximum logarithm of odds score [MLS] = 1.2; P = 0.02), no association was detected. Further linkage analysis revealed suggestive evidence for linkage of chromosome 18q21 to type 1 diabetes in 882 multiplex families (MLS = 2.2; lambdas = 1.2; P = 0.001), and by meta-analysis the orthologous region (also on chromosome 18) is linked to diabetes in rodents (P = 9 x 10(-4)). By meta-analysis, both human chromosome 18q12-q21 and the rodent orthologous region show positive evidence for linkage to an autoimmune phenotype (P = 0.004 and 2 x 10(-8), respectively, empirical P = 0.01 and 2 x 10(-4), respectively). In the diabetes-linked region of chromosome 18q12-q21, a candidate gene, deleted in colorectal carcinoma (DCC), was tested for association with human autoimmunity in 3,380 families with type 1 diabetes, MS, and RA. A haplotype ("2-10") of two newly characterized microsatellite markers within DCC showed evidence for association with autoimmunity (P = 5 x 10(-6)). Collectively, these data suggest that a locus (or loci) exists on human chromosome 18q12-q21 that influences multiple autoimmune diseases and that this association might be conserved between species.

High-Efficiency Light Coupling in a Submicrometric Silicon-on-Insulator Waveguide

Light coupling into a sub-micrometer-thick waveguide is usually done through a grating coupler. Coupling efficiency is strongly enhanced by addition of a mirror above the grating. This new kind of coupler can be designed to achieve efficiencies as great as 80%. Numerical calculations for a high-angular-spread Gaussian incident beam are compared with experimental results obtained for a standard silicon-on-insulator waveguide.

Interethnic studies of TNF polymorphisms confirm the likely presence of a second MHC susceptibility locus in ankylosing spondylitis

The objective of this study was to investigate TNF promoter region polymorphisms for association with susceptibility to ankylosing spondylitis (AS). The TNF -238 and -308 polymorphisms were genotyped in 306 English AS cases and 204 ethnically matched healthy B27-positive controls, and 96 southern German AS cases, 58 B27-positive and 251 B27-negative ethnically matched controls. Additionally, the TNF -376 polymorphism was genotyped in the southern German cases and controls. In the southern German AS patients a significant reduction in TNF -308.2 alleles was seen, compared with B27 positive controls (odds ratio 0.4, P = 0.03, 95% confidence interval 0.2-0.9), but no difference in allele frequencies was observed at TNF -238. Significant association between AS and both TNF -238 and TNF -308 was excluded in the English cases. These results confirm previous observations in the southern German population of association between TNF promoter region polymorphisms and AS, but the lack of association in the English population suggests that these polymorphisms themselves are unlikely to be directly involved. More likely, a second, non-HLA-B, MHC locus is involved in susceptibility to AS in these two populations.

Polymorphisms of the CYP2D6 gene increase susceptibility to ankylosing spondylitis

Ankylosing spondylitis (AS) is a common and highly familial rheumatic disorder. The sibling recurrence risk ratio for the disease is 63 and heritability assessed in twins >90%. Although MHC genes, including HLA-B27, contribute only 20-50% of the genetic risk for the disease, no non-MHC gene has yet been convincingly demonstrated to influence either susceptibility to the disease or its phenotypic expression. Previous linkage and association studies have suggested the presence of a susceptibility gene for AS close to, or within, the cytochrome P450 2D6 gene (CYP2D6, debrisoquine hydroxylase) located at chromosome 22q13.1. We performed a linkage study of chromosome 22 in 200 families with AS affected sibling-pairs. Association of alleles of the CYP2D6 gene was examined by both case-control and within-family means. For case-control studies, 617 unrelated individuals with AS (361 probands from sibling-pair and parent-case trio families and 256 unrelated non-familial sporadic cases) and 402 healthy ethnically matched controls were employed. For within-family association studies, 361 families including 161 parent-case trios and 200 affected sibling-pair families were employed. Homozygosity for poor metabolizer alleles was found to be associated with AS. Heterozygosity for the most frequent poor metabolizer allele (CYP2D6*4) was not associated with increased susceptibility to AS. Significant within-family association of CYP2D6*4 alleles and AS was demonstrated. Weak linkage was also demonstrated between CYP2D6 and AS. We postulate that altered metabolism of a natural toxin or antigen by the CYP2D6 gene may increase susceptibility to AS.

Cardiovascular malformations in experimental congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Newborns with congenital diaphragmatic hernia (CDH) frequently have associated anomalies that have a major impact on survival rate independent of pulmonary hypoplasia and pulmonary hypertension. Cardiovascular malformations (CVM) represent a major group of lethal extrapulmonary abnormalities that often assume greatest prognostic significance in most CDH studies. Animal models resembling human CDH may aid knowledge of the basic embryology that leads to the coexpression of CDH and CVM. This study, therefore, analyzed the incidence and spectrum of CVM in fetal rats with CDH.

METHODS

Left-sided CDH (LCDH) was induced in fetal rats by the maternal administration of 100 mg of nitrofen by gavage on day 9.5 gestation (term, day 22). Control animals received olive oil (OO) and were used for comparative analysis. Fetal rats were harvested by cesarean section on day 21.5 or day 22, histologically processed and examined for CVM.

RESULTS

A significant number of CVM were observed in 15 of 60 (25%) LCDH rats compared with 4 of 60 (6.7%) nitrofen non-CDH rats (P = .01). The spectrum of abnormalities in CDH included ventricular septal (VSD) defects (n = 6), vascular rings (n = 4), anomalous subclavian arteries (n = 3), atrioventricular septal defects (n = 1) and Fallot's tetralogy (n = 1). A VSD (n = 1), double-outlet right ventricle VSD (n = 1) and Fallot's tetralogy (n = 2) were noted in nitrofen non-CDH rats. Control (OO) fetal rats (n = 60) displayed no malformations.

CONCLUSIONS

These results confirm a significant incidence and spectrum of CVM in a teratogenic CDH model similar to that seen in humans with CDH. The findings of this study reinforce the validity of the nitrofen model as a research tool to uncover the genetic and molecular mechanisms responsible for the genesis of CDH and allied malformations.

A linkage study of schizophrenia to markers within Xp11 near the MAOB gene

A sex chromosome locus for psychosis has been considered on the basis of some sex differences in genetic risk and expression of illness, and an association with X-chromosome anomalies. Previous molecular genetic studies produced weak evidence for linkage of schizophrenia to the proximal short arm of the X-chromosome, while some other regions were not ruled out. Here we report an attempt to expand the Xp findings in: (i) a multicenter collaboration focusing on 92 families with a maternal pattern of inheritance (Study I), and (ii) an independent sample of 34 families unselected for parental mode of transmission (Study II). In the multicenter study, a parametric analysis resulted in positive lod scores (highest of 1.97 for dominant and 1.19 for recessive inheritance at a theta of 0.20) for locus DXS7, with scores below 0.50 for other markers in this region (MAOB, DXS228, and ARAF1). Significant allele sharing among affected sibling pairs was present at DXS7. In the second study, positive lod scores were observed at MAOB (highest of 2.16 at a theta of 0.05 for dominant and 1.64 at a theta of 0.00 for recessive models) and ALAS2 (the highest of 1.36 at a theta of 0.05 for a recessive model), with significant allele sharing (P = 0.003 and 0.01, respectively) at these two loci. These five markers are mapped within a small region of Xp11. Thus, although substantial regions of the X-chromosome have been investigated without evidence for linkage being found, a locus predisposing to schizophrenia in the proximal short arm of the X-chromosome is not excluded.

Optimized coupling of a Gaussian beam into an optical waveguide with a grating coupler: comparison of experimental and theoretical results

The coupling efficiency of grating couplers is derived for a Gaussian incident beam. Its optimum value depends on the beam waist and on the position of a light spot with respect to the coupler edge for given grating parameters. The characteristic coupling length has been experimentally determined for the grating coupler studied. Relative measurements of the coupling efficiency as a function of incident beam characteristics are in good agreement with the numerical results.

A polymorphic and hypervariable locus in the pseudoautosomal region of the CBA/H mouse sex chromosomes

We have identified a genomic locus (DXYH1) that is polymorphic and hypervariable within the CBA/H colony. Using a panel of C57BL/6 x Mus spretus backcross offspring, it was mapped to the distal end of the X chromosome. Pseudoautosomal inheritance was demonstrated through three generations of CBA/H x CBA/H and CBA/H x C57BL/6 crosses and confirmed through linkage to the Sxr locus in X/Y Sxr x 3H1 crosses. Meiotic recombination frequencies place DXYH1 similar 28% into the pseudoautosomal region from the boundary. The de novo generation of CBA/H variant DXYH1 restriction fragment length polymorphisms during spermatogenesis is suggestive of the germline instability associated with hypermutable human minisatellites. The absence of DXYH1-related sequences in Mus spretus provides DNA sequence evidence to support the observed failure of X-Y pairing during meiosis and consequent hybrid infertility in C57BL/6 x Mus spretus male F1 offspring.

Co-amplification to tail-to-tail copies of MuRVY and IAPE retroviral genomes on the Mus musculus Y chromosome

We have isolated a clone from a C57BL/6 genomic library that contains both part of the Y Chromosome-specific 8.7 kbp MuRVY genome (Hutchinson and Eicher, J. Virol. 63, 4043, 1989) and a full-length 8.3 kbp Intracisternal A Particle genome (IAPE-Y), in a tail-to-tail organization. Although IAPs are encoded by a disperse multigene family (approximately 1000 copies per haploid genome), we present evidence that a significant proportion of the IAP-related sequences are present on the Y Chromosome (Chr) and that a >25 kbp genomic sequence, which contains the two proviral genomes, has been amplified on the Y Chr. Two discrete amplified families of MuRVY retroviral genomes distinguishable by a polymorphic restriction site were detected, suggestive that amplification occurred in incremental stages. The presence of MuRVY-related DNA sequences, but absence of IAPE-Y-related DNA sequences in Mus spretus suggests that the IAPE-Y retrotransposition event occurred after the evolutionary divergence of the lineages leading to Mus musculus and Mus spretus, and that the amplification of MuRVY occurred independently in the two lineages.

Complex Y chromosome aberrations are a recurrent secondary event in radiation-induced murine acute myeloid leukaemia

Arbitrarily primed-PCR analysis of DNA from male CBA/H radiation-induced leukaemic spleens revealed the loss of an approximately 350-bp sequence in several leukaemias. We have isolated a lambda EMBL3 C57BL/6 genomic subclone (pJB1) which hybridizes to the AP-PCR probe and is located on the Y chromosome. Southern blot analyses using the pJB1 probe indicate that the genomic sequence was deleted in five of 14 leukaemias. Cytogenetic analyses of 31 X-ray induced leukaemias in male CBA/H mice revealed, in addition to the characteristic partial deletion of chromosome 2 (28/31 leukaemias), a high incidence (16/31) of the loss of an intact Y chromosome. Comparison of the Southern blot and cytogenetic analyses of the leukaemias demonstrate a significant lack of correspondence between the loss of an intact Y chromosome and Y chromosome-specific DNA sequences, suggesting that Y chromosome aberrations are complex. Whereas partial deletion of chromosome 2 can be detected in 6% of bone marrow cells within 6-11 days of irradiation, no Y chromosome involvement was detected, indicating that Y chromosome aberrations are a late event in radiation-induced leukaemogenesis. These findings are comparable to the loss of sex chromosomes in human t(8;21) AML.

Localization of an epithelial-specific receptor kinase (EDDR1) to chromosome 6q16

A protein receptor tyrosine kinase (EDDR1) has been isolated from a complementary DNA library of SKOV-3, an epithelial ovarian cancer cell line. The primary structure of the predicted amino acid sequence of the protein shows a novel N-terminal region that has homology to a factor VIII-like domain. The C-terminal catalytic domain has all of the canonical sequence motifs of a receptor tyrosine kinase with homology to the TRK-2H protein (49%), which suggests that it is a type II receptor. It is expressed in epithelial cells of several tissues. To determine the chromosomal localization of the gene, somatic cell hybrids were analyzed by PCR amplification using oligonucleotide primers specific for EDDR1. Segregation was observed to a hybrid containing human chromosome 6. Cosmids for EDDR1 were isolated from a human chromosome 6 cosmid library and were shown by fluorescence in situ hybridization to map to 6q16.

Isolation and characterization of an epithelial-specific receptor tyrosine kinase from an ovarian cancer cell line

A protein receptor tyrosine kinase (RTK 6) has been isolated from a complementary DNA library of SKOV-3, an epithelial ovarian cancer cell line, using a polymerase chain reaction (PCR)-mediated approach. The primary structure of the predicted amino acid sequence of the protein shows a novel NH2-terminal region which has homology to a factor VIII-like domain. The juxtamembrane region is proline and glycine rich and is the longest for any known receptor kinase. The COOH-terminal catalytic domain has all of the canonical sequence motifs of a receptor tyrosine kinase with homology to the TRK-2H protein (49%). A single transcript of 4.5 kilobases is expressed at low levels in heart, placenta, lung, liver, muscle, kidney, and pancreas, with high levels of expression in the brain. Ribonuclease protection assay showed a varying level of expression of message in a panel of eight ovarian cancer cell lines compared to placenta. In situ hybridization analysis demonstrated localization of mRNA in the epithelial cells of the ovary, kidney, small bowel, lung, thymus, and brain. There was a lower level of message in normal, benign, and borderline tumors of the ovary compared to malignant tumors of the ovary. Polyclonal antisera raised against a COOH-terminal synthetic peptide recognize a M(r) 140,000 protein in ovarian cancer cells, which autophosphorylates in an in vitro kinase assay.

Partial sequence data from three evolutionarily conserved loci from the proximal short arm of the human X chromosome; assignment of DXF34S1 to Xp11.21-cen

DNA sequence data have been obtained from three clones derived from the human X chromosome which contain evolutionarily conserved sequences. Primers have been designed which enable these loci to be defined as sequence-tagged-sites (STS's). The assignment of one of the loci, DXF34S1, has been refined to Xp11.21-cen, thus limiting the novel pericentromeric segment of homology defined by this locus to the extreme proximal region of Xp.