Epigenetic loss of putative tumor suppressor SFRP3 correlates with poor prognosis of lung adenocarcinoma patients

Secreted frizzled related protein 3 (SFRP3) contains a cysteine-rich domain (CRD) that shares homology with Frizzled CRD and regulates WNT signaling. Independent studies showed epigenetic silencing of SFRP3 in melanoma and hepatocellular carcinoma. Moreover, a tumor suppressive function of SFRP3 was shown in androgen-independent prostate and gastric cancer cells. The current study is the first to investigate SFRP3 expression and its potential clinical impact on non-small cell lung carcinoma (NSCLC). WNT signaling components present on NSCLC subtypes were preliminary elucidated by expression data of The Cancer Genome Atlas (TCGA). We identified a distinct expression signature of relevant WNT signaling components that differ between adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC). Of interest, canonical WNT signaling is predominant in LUAD samples and non-canonical WNT signaling is predominant in LUSC. In line, high SFRP3 expression resulted in beneficial clinical outcome for LUAD but not for LUSC patients. Furthermore, SFRP3 mRNA expression was significantly decreased in NSCLC tissue compared to normal lung samples. TCGA data verified the reduction of SFRP3 in LUAD and LUSC patients. Moreover, DNA hypermethylation of SFRP3 was evaluated in the TCGA methylation dataset resulting in epigenetic inactivation of SFRP3 expression in LUAD, but not in LUSC, and was validated by pyrosequencing of our NSCLC tissue cohort and in vitro demethylation experiments. Immunohistochemistry confirmed SFRP3 protein downregulation in primary NSCLC and indicated abundant expression in normal lung tissue. Two adenocarcinoma gain-of-function models were used to analyze the functional impact of SFRP3 on cell proliferation and regulation of CyclinD1 expression in vitro. Our results indicate that SFRP3 acts as a novel putative tumor suppressor gene in adenocarcinoma of the lung possibly regulating canonical WNT signaling.     

Spectral diversity among members of the green fluorescent protein family in hydroid jellyfish (Cnidaria,Hydrozoa)

The cDNAs encoding the genes of new proteins, homologous to the well-known Green Fluorescent Protein (GFP) from the hydroid jellyfish Aequorea victoria, were cloned. Two green fluorescent proteins from one unidentified anthomedusa, a yellow fluorescent protein from Phialidium sp., and a nonfluorescent chromoprotein from another unidentified anthomedusa were characterized. Thus, a broad diversity of GFP-like proteins among the organisms of the class Hydrozoa in both spectral properties and primary structure was shown.Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 1, 2005, pp. 49–53.Original Russian Text Copyright © 2005 by Yanushevich, Shagin, Fradkov, Shakhbazov, Barsova, Gurskaya, Labas, Matz, K. Lukyanov, S. Lukyanov.     

Chemical Composition of Exosporium from Spores of Bacillus cereus

Homogeneous fragments of exosporium were extricated in centigram amounts from dormant spores of Bacillus cereus and analyzed for intrinsic constituents. The membrane proved to be chemically complex but not unique, consisting mainly of protein (52%), amino and neutral polysaccharides (20%), lipids (18%), and ash (4%). Seventeen common amino acids were identified by chromatography, and were present in usual proportions except for low levels of cystine-cysteine, methionine, tyrosine, and histidine. Glucosamine was the only amino sugar, and glucose and rhamnose were the principal neutral sugars. The lipid fraction contained 5.5% cardiolipin as the only phospholipid, 12.5% neutral lipids, and at least 19 fatty acids, among which normal C(16) and C(18) ones predominated. Calcium and phosphorus occurred in the ash. Small amounts of teichoic, ribonucleic, and dipicolinic acids were believed to represent contamination.     

Inhibition of adenosine deaminase activity reveals an intense active transport of adenosine into neurons in primary cultures

It is often assumed that adenosine transport into brain cells occurs by facilitated diffusion and that the continued net uptake of adenosine depends on its subsequent metabolism, which keeps the intracellular concentration of unmetabolized adenosine low and thus maintains a concentration gradient. If that is the case, inhibition of adenosine metabolism should decrease uptake. We have previously reported a considerable deamination of accumulated adenosine to inosine in primary cultures of cerebral cortical neurons. A relatively specific adenosine deaminase inhibitor, 2-deoxycoformycin, was used in the present study. In the presence of this drug, the adenosine content (pool size) increased many fold without any decrease in total influx of adenosine. Influx of accumulated adenosine took place against a concentration gradient, demonstrating that a metabolic degradation of accumulated adenosine is not required to drive adenosine uptake. This does not preclude that under normal conditionssome adenosine may get into the cells by diffusion.     

Bimodal signatures of germline methylation are linked with gene expression plasticity in the coral Acropora millepora

Background

In invertebrates, genes belonging to dynamically regulated functional categories appear to be less methylated than “housekeeping” genes, suggesting that DNA methylation may modulate gene expression plasticity. To date, however, experimental evidence to support this hypothesis across different natural habitats has been lacking.

Results

Gene expression profiles were generated from 30 pairs of genetically identical fragments of coral Acropora millepora reciprocally transplanted between distinct natural habitats for 3 months. Gene expression was analyzed in the context of normalized CpG content, a well-established signature of historical germline DNA methylation. Genes with weak methylation signatures were more likely to demonstrate differential expression based on both transplant environment and population of origin than genes with strong methylation signatures. Moreover, the magnitude of expression differences due to environment and population were greater for genes with weak methylation signatures.

Conclusions

Our results support a connection between differential germline methylation and gene expression flexibility across environments and populations. Studies of phylogenetically basal invertebrates such as corals will further elucidate the fundamental functional aspects of gene body methylation in Metazoa.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1109) contains supplementary material, which is available to authorized users.