The Wnt pathway regulator DKK1 is preferentially expressed in hormone-resistant breast tumours and in some common cancer types

In addition to new tumour antigens, new prognostic and diagnostic markers are needed for common cancers. In this study, we report the expression of Dickkopf-1 (DKK1) in multiple common cancers. This constitutes a comprehensive analysis of the DKK1 expression profile. Dickkopf-1 expression was evaluated by classical and quantitative reverse transcriptase–polymerase chain reaction (RT–PCR) and enzyme-linked immunosorbant assay for protein determination, in cancer lines and clinical specimens of several cancer origins. For breast cancer, expression was correlated with clinicopathological parameters. Dickkopf-1 expression was confirmed in several cancer cell lines derived from breast and other common cancers. Dickkopf-1 protein secretion was documented in breast, prostate and lung cancer lines, but was negligible in melanoma. Analysis of DKK1 expression in human cancer specimens revealed DKK1 expression in breast (21 out of 73), lung (11 out of 23) and kidney cancers (six out of 20). Interestingly, DKK1 was preferentially expressed in oestrogen and progesterone receptor-negative tumours (ER⁻/PR⁻; P=0.005) and in tumours from women with a family history of breast cancer (P=0.024). Importantly, DKK1 protein production was confirmed in multiple breast cancer specimens that were positive by RT–PCR. This work establishes DKK1 as a potential prognostic and diagnostic marker for cohorts of breast cancer patients with poor prognosis. Dickkopf-1 may also become a relevant candidate target for immunotherapy of different cancers.

Phylogenetic inferences from chloroplast chlB gene sequences of Nephrolepis exaltata (Filicopsida), Ephedra altissima (Gnetopsida), and diverse land plants

The chloroplast chlB gene, involved in light-independent protochlorophyllide reduction, has been reported present in algae, in one bryophyte and some gymnosperms, but absent from various angiosperms. In this study, the complete or nearly complete chlB gene sequences from the fern Nephrolepis exaltata and the seed plant Ephedra altissima were determined. Comparison of five available land plant chlB sequences with a similar set of rbcL sequences, encoding the large subunit of ribulose 1,5-bisphosphate carboxylase, showed that the chlB rate of nonsynonymous substitution was about fourfold higher than for rbcL, while the chlB phylogeny resulted in a better resolution of the clades surveyed. The presence of chlB in other lineages of land plants was determined by amplification and sequencing of a chlB internal fragment, which was recovered from all the nonangiosperm taxa surveyed except Psilotum and Gnetum. The phylogenies derived from 23 land plant chlB sequences were largely congruent with the relationships inferred from other analyses. Neighbor-joining analysis supported the view that bryophytes are paraphyletic, with mosses as sister group to vascular plants. Within lycopodiophytes, Selaginella clustered with Lycopodium, but Isoetes was located basally to the other land plants. The various ferns surveyed were found to form a coherent group which derived after horsetails and which was sister group to seed plants. Our results strongly supported monophyly of the conifers-Ginkgo-cycads clade, where conifers were sister group to Ginkgo and cycads. The various phylogenies suggested an early divergence of the seed plant lineage leading to Ephedra.

Stage-specific transcription of the homebox gene Bnhd1 in young tissues and flowers of Brassica napus

The Bnhd1 cDNA, only distantly related to published homebox gene sequences, was isolated from Brassica napus by the polymerase chain reaction. The Bnhd1 transcript was detected in all organs of young seedlings, but only in the youngest leaves and flowers of mature plants. A 4- and 7-fold increase in transcription levels was observed after wounding of young roots and leaves, respectively.

Sequence and expression of a gene encoding a protein with RNA-binding and glycine-rich domains in Brassica napus

A cDNA clone and its genomic counterpart were isolated from Brassica napus. The encoded protein, BnGRP10, is composed of two modules, the first one is homologous to many RNA-binding domains of ribonucleoproteins, and the second is 73% glycine rich. Northern analysis shows that this gene is expressed only in roots and stems and is slightly induced by different stress conditions.

Isolation of Lhcb3 sequences from Brassica napus: evidence for conserved genes encoding LHCII type III chlorophyll a/b binding proteins

Three closely related sequences were isolated from Brassica napus genomic DNA and were identified as Lhcb3 (genes encoding type III chlorophyll a/b binding proteins of LHCII, the major light-harvesting complex of photosystem II). These genes, as was observed for a tomato Lhcb3, contain two introns and yield both divergent and conserved predicted amino acid segments as compared with type I and type II polypeptides. One of the B. napus genes, designated Lhcb3*1, is transcribed in vivo, since it is identical to corresponding sequences in a cDNA clone. The protein deduced from another sequence, Lhcb3*2, appears as the most divergent type III so far characterized. The partial sequence of a third gene, Lhcb3*3, was also recovered. The 5' noncoding sequences of Lhcb3*1 and Lhcb3*2, in the far upstream region, are characterized by an extremely high AT content and extensive direct repeats. In the near upstream region, two long Lhcb3*2 segments are very similar to a segment proposed as containing regulatory signals in Lhcb3*1. Specific binding of nuclear proteins to Lhcb3*1 promoter fragments was detected by electrophoretic mobility-shift assays. The evolutionary relationship between genes for type III polypeptides and the other types present in LHCII is discussed.

Priming of the human neutrophil respiratory burst by granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha involves regulation at a post-cell surface receptor level. Enhancement of the effect of agents which directly activate G proteins

Over the last few years, several studies showing that production of superoxide by neutrophils in response to chemotactic factors such as FMLP is enhanced after preincubation of the cells with granulocyte-macrophage (GM)-CSF or TNF-alpha have been published. Subsequent reports have indicated that this effect of the cytokines may be mediated by modulation of the number and/or affinity of surface receptors for FMLP. In the present study we have investigated the effect of preincubation with GM-CSF and TNF-alpha on the oxidative burst induced by sodium fluoride and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S)-agents which directly activate guanine-nucleotide binding proteins in neutrophils. Pretreatment of neutrophils with either GM-CSF or TNF-alpha dose-dependently enhanced the production of superoxide induced by NaF, as determined by the superoxide dismutase-inhibitable reduction of ferricytochrome c. Furthermore, preincubation of neutrophils with these cytokines enhanced the production of hydrogen peroxide induced by GTP gamma S in electroporated neutrophils. Because both NaF and GTP gamma S directly activate G proteins independently of external receptor-G protein interaction, these results imply that both GM-CSF and TNF-alpha alter the neutrophil signal transduction pathway in response to subsequent agonists independently of a modulation in the expression of the cell surface receptors for such agonists.

Priming of the human neutrophil respiratory burst by granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha involves regulation at a post-cell surface receptor level. Enhancement of the effect of agents which directly activate G proteins

Over the last few years, several studies showing that production of superoxide by neutrophils in response to chemotactic factors such as FMLP is enhanced after preincubation of the cells with granulocyte-macrophage (GM)-CSF or TNF-alpha have been published. Subsequent reports have indicated that this effect of the cytokines may be mediated by modulation of the number and/or affinity of surface receptors for FMLP. In the present study we have investigated the effect of preincubation with GM-CSF and TNF-alpha on the oxidative burst induced by sodium fluoride and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S)-agents which directly activate guanine-nucleotide binding proteins in neutrophils. Pretreatment of neutrophils with either GM-CSF or TNF-alpha dose-dependently enhanced the production of superoxide induced by NaF, as determined by the superoxide dismutase-inhibitable reduction of ferricytochrome c. Furthermore, preincubation of neutrophils with these cytokines enhanced the production of hydrogen peroxide induced by GTP gamma S in electroporated neutrophils. Because both NaF and GTP gamma S directly activate G proteins independently of external receptor-G protein interaction, these results imply that both GM-CSF and TNF-alpha alter the neutrophil signal transduction pathway in response to subsequent agonists independently of a modulation in the expression of the cell surface receptors for such agonists.