Serum immunoassay of a small cell lung cancer associated ganglioside: development of a sensitive scintillation proximity assay

We here report an enzyme linked immunosorbent assay (ELISA) and a scintillation proximity assay (SPA) for detection of the ganglioside FucGM₁ in sera from small cell lung cancer (SCLC) patients. The SPA was more sensitive and reproducible than the ELISA. In this assay, monoclonal antibodies specific for FucGM₁ were bound to SPA particles and incubated with labelled FucGM₁ and 100 µl test-serum overnight, and counted in a -counter. The sensitivity was 0.2 ng. Seven out of twenty sera from SCLC patients were positive, whereas none of twenty sera from healthy individuals were positive for FucGM₁. The SPA was more sensitive than the previously reported HPTLC as well as a direct ELISA.Abbreviations MAb monoclonal antibody - SPA scintillation proximity assay - HPTLC high performance thin layer chromatography - SCLC small cell lung cancer - FucGM₁ Fuc1-2Gal1-3GalNAc1-4(NeuAc2-3)-Gal1-4Glc1-1Cer - ELISA enzyme linked immunosorbent assay - FCS foetal calf serum - PBS phosphate buffered saline     

8-Hydroxydeoxyguanosine in DNA from TPA-Stimulated Human Granulocytes

8-Hydroxydeoxyguanosine (8-OHdG) is now widely used as a sensitive marker of oxidative damage to DNA. When human granulocytes are stimulated with TPA, they release a large quantity of reactive oxygen species (superoxide, hydrogen peroxide) which might be expected to generate hydroxyl radicals (OH-) which in turn could produce 8-OHdG in the DNA. There had been considerable debate as to whether OH -is detectable in stimulated granulocytes; most workers now agree that none can be detected, unless exogenous iron is added. An earlier report had described that 8-OHdG (a marker of OH -) was increased in the DNA of TPA-stimulated, compared to control, granulocytes. We have repeated this experiment and have been unable to reproduce this Finding. We conclude that the amount of 8-OHdG produced in the DNA of TPA-stimulated human ganulocytes is indistinguishable from that seen in control (unstimulated) cells (less than one 8- OHdG/10⁵ dG).     

Corticosteroid-induced cleft palate in mice and H-2 haplotype: Maternal and embryonic effects

This report confirms and expands on the original preliminary observations made by Bonner and Slavkin that corticosteroid-induced cleft palate in mice is associated with H-2 haplotype. Using three congenic strains, B10, B10.A, and B10.D2, our studies demonstrate that B10.A (H-2 ^b) is most susceptible and B10.D2 (H-2 ^d) is least susceptible, B10 (H-2 ^b) being intermediate. Variation in fetal loss among strains accounts for less than 1 percent of the variation in cleft-palate frequency among strains; variation in H-2 haplotype, however, accounts for more than 60 percent of the variation in cleft-palate frequency. With regard to all possible reciprocal F₁ hybrids, our results indicate that while there is a significant maternal effect, maternal haplotype can account for only 11 percent of the variation in cleft-palate frequency among crosses. Embryonic haplotype accounts for 17 percent of the variation, which is indicative of an important embryonic effect. Finally, our studies suggest that susceptibility to corticosteroid-induced cleft palate is associated with the K end of the H-2 complex.     

Synergistic anti-proliferative and pro-apoptotic activity of combined therapy with bortezomib, a proteasome inhibitor, with anti-epidermal growth factor receptor (EGFR) drugs in human cancer cells

The proteasome plays a pivotal role in the turnover of regulatory transduction proteins induced by activated cell membrane growth factor receptors. The epidermal growth factor receptor (EGFR) pathway is crucial in the development and progression of human epithelial cancers. Proteasome inhibition may sensitize human cancer cell lines to EGFR inhibitors. We investigated the growth inhibitory and pro-apoptotic effects of the proteasome inhibitor bortezomib in combination with anti-EGFR drugs, such as gefitinib, vandetanib, and cetuximab in EGFR-expressing human cancer cell lines. Bortezomib determined dose-dependent growth inhibition in a nine cancer cell line panel (IC(50) values, range 6-42 nM). A significant synergistic growth inhibitory effect was observed with the combination of bortezomib and each EGFR inhibitor in all cell lines (combination index, CI, range 0.10-0.55), which was accompanied by a significant induction in apoptosis by the combined treatment with bortezomib, cetuximab and vandetanib. In HCT-116 colon cancer and A549 lung adenocarcinoma cells, bortezomib plus EGFR inhibitor treatment induced a more effective inhibition of EGFR-activated down-stream signals, including a marked suppression in activated, phosphorylated Akt (P-Akt). In contrast, overexpression of a constitutively active P-Akt protected A549 cells by cell growth inhibition and apoptosis following treatment with bortezomib and EGFR inhibitors. The combined treatment with bortezomib and EGFR inhibitors has a synergistic growth inhibitory and pro-apoptotic activity in different human cancer cells which possess a functional EGFR-dependent autocrine growth pathway through to a more efficient and sustained inhibition of Akt.     

New insights into the butyric acid metabolism of Clostridium acetobutylicum

Biosynthesis of acetone and n-butanol is naturally restricted to the group of solventogenic clostridia with Clostridium acetobutylicum being the model organism for acetone-butanol-ethanol (ABE) fermentation. According to limited genetic tools, only a few rational metabolic engineering approaches were conducted in the past to improve the production of butanol, an advanced biofuel. In this study, a phosphotransbutyrylase-(Ptb) negative mutant, C. acetobutylicum ptb::int(87), was generated using the ClosTron methodology for targeted gene knock-out and resulted in a distinct butyrate-negative phenotype. The major end products of fermentation experiments without pH control were acetate (3.2?g/l), lactate (4.0?g/l), and butanol (3.4?g/l). The product pattern of the ptb mutant was altered to high ethanol (12.1?g/l) and butanol (8.0?g/l) titers in pH?≥?5.0-regulated fermentations. Glucose fed-batch cultivation elevated the ethanol concentration to 32.4?g/l, yielding a more than fourfold increased alcohol to acetone ratio as compared to the wildtype. Although butyrate was never detected in cultures of C. acetobutylicum ptb::int(87), the mutant was still capable to take up butyrate when externally added during the late exponential growth phase. These findings suggest that alternative pathways of butyrate re-assimilation exist in C. acetobutylicum, supposably mediated by acetoacetyl-CoA:acyl-CoA transferase and acetoacetate decarboxylase, as well as reverse reactions of butyrate kinase and Ptb with respect to previous studies.     

Species relationships in the genus Vasconcellea (Caricaceae) based on molecular and morphological evidence

Validity of the taxa currently recognized in the genus Vasconcellea was analyzed by investigating morphological and molecular data from 105 specimens of this genus and six specimens of the related genus Carica. Taxon identification of these specimens was compared with clustering in two phenetic dendrograms generated with 36 morphological characters and 254 amplified fragment length polymorphic (AFLP) markers. Moreover, cytoplasmic haplotypes were assessed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) of one mitochondrial and two chloroplast DNA regions. Results show that the morphological data set, containing mainly vegetative characteristics, merely reveals external resemblance between specimens, which is not directly associated with genetic relationships and taxon validity. Phenotypic plasticity and intercompatibility between several species are likely to confuse morphological delimitation of the taxa. Based on the results of our study, several specimens that could not be identified with the currently used identification key (1) could be attributed to a known taxon, which should be extended to include a higher range of morphological variability or (2) could be hypothesized to be of hybrid origin. Because of the high intraspecific variation within V. microcarpa and V. × heilbornii, revision of these taxa is recommended.     

GSK3β-Dependent Phosphorylation Alters DNA Binding,Transactivity and Half-Life of the Transcription Factor USF2

The upstream stimulatory factor 2 (USF2) is a regulator of important cellular processes and is supposed to have also a role during tumor development. However, the knowledge about the mechanisms that control the function of USF2 is limited. The data of the current study show that USF2 function is regulated by phosphorylation and identified GSK3β as an USF2-phosphorylating kinase. The phosphorylation sites within USF2 could be mapped to serine 155 and threonine 230. In silico analyses of the 3-dimensional structure revealed that phosphorylation of USF2 by GSK3β converts it to a more open conformation which may influence transactivity, DNA binding and target gene expression. Indeed, experiments with GSK-3β-deficient cells revealed that USF2 transactivity, DNA binding and target gene expression were reduced upon lack of GSK3β. Further, experiments with USF2 variants mimicking GSK3β phosphorylated USF2 in GSK3β-deficient cells showed that phosphorylation of USF2 by GSK3β did not affect cell proliferation but increased cell migration. Together, this study reports a new mechanism by which USF2 may contribute to cancerogenesis.