Mucin 13: structure, function, and potential roles in cancer pathogenesis

Mucin 13 (MUC13) is a high-molecular-weight transmembrane glycoprotein that is frequently and aberrantly expressed in a variety of epithelial carcinomas, including gastric, colorectal, and ovarian cancers. On the basis of the high expression of MUC13 in cancer cells as well as recent laboratory findings suggesting a malignant phenotype of MUC13-transfected cell lines, the oncogenic potential of MUC13 has emerged. The various functional domains of MUC13 may confer oncogenic potential to MUC13. For example, the bulky extracellular domain with extensive modification with glycan chains may prevent cell-cell and cell-extracellular matrix binding whereas the cytoplasmic tail containing serine and tyrosine residues for potential phosphorylation may participate in cell signaling. MUC13 exhibits the characteristics suitable as an early marker for cancer screening and presents a promising target for antibody-guided targeted therapy.     

Dipeptidyl peptidase III: a multifaceted oligopeptide N-end cutter

Dipeptidyl peptidase III (DPP III), the sole member and representative of the M49 family of metallopeptidases, is a zinc-dependent aminopeptidase. It sequentially hydrolyses dipeptides from the N-terminal of oligopeptides ranging from three to 10 amino acid residues. Although implicated in an array of pathophysiological phenomena, the precise function of this peptidase is still unclear. However, a number of studies advocate its contribution in terminal stages of protein turnover. Altered expression of DPP III which suggests its involvement in primary ovarian carcinoma, oxidative stress (Nrf2 nuclear localization), pain, inflammation and cataractogenesis has recently led to resurgence of interest in delineating the role of the peptidase in these pathophysiological processes. This review article intends to bring forth the latest updates in this arena which may serve as a base for future studies on the peptidase.     

Exosomes mediate LTB4 release during neutrophil chemotaxis

Leukotriene B₄ (LTB₄) is secreted by chemotactic neutrophils, forming a secondary gradient that amplifies the reach of primary chemoattractants. This strategy increases the recruitment range for neutrophils and is important during inflammation. Here, we show that LTB₄ and its synthesizing enzymes localize to intracellular multivesicular bodies, which, upon stimulation, release their content as exosomes. Purified exosomes can activate resting neutrophils and elicit chemotactic activity in an LTB₄ receptor-dependent manner. Inhibition of exosome release leads to loss of directional motility with concomitant loss of LTB₄ release. Our findings establish that the exosomal pool of LTB₄ acts in an autocrine fashion to sensitize neutrophils towards the primary chemoattractant, and in a paracrine fashion to mediate the recruitment of neighboring neutrophils in trans. We envision that this mechanism is used by other signals to foster communication between cells in harsh extracellular environments.     

Structure of the Dengue virus helicase/nucleoside triphosphatase catalytic domain at a resolution of 2.4 A

Dengue fever is an important emerging public health concern, with several million viral infections occurring annually, for which no effective therapy currently exists. The NS3 protein from Dengue virus is a multifunctional protein of 69 kDa, endowed with protease, helicase, and nucleoside 5'-triphosphatase (NTPase) activities. Thus, NS3 plays an important role in viral replication and represents a very interesting target for the development of specific antiviral inhibitors. We present the structure of an enzymatically active fragment of the Dengue virus NTPase/helicase catalytic domain to 2.4 A resolution. The structure is composed of three domains, displays an asymmetric distribution of charges on its surface, and contains a tunnel large enough to accommodate single-stranded RNA. Its C-terminal domain adopts a new fold compared to the NS3 helicase of hepatitis C virus, which has interesting implications for the evolution of the Flaviviridae replication complex. A bound sulfate ion reveals residues involved in the metal-dependent NTPase catalytic mechanism. Comparison with the NS3 hepatitis C virus helicase complexed to single-stranded DNA would place the 3' single-stranded tail of a nucleic acid duplex in the tunnel that runs across the basic face of the protein. A possible model for the unwinding mechanism is proposed.     

<Emphasis Type="Italic">Kuth</Emphasis> (<Emphasis Type="Italic">Saussurea lappa</Emphasis>) cultivation in the cold desert environment of the Lahaul valley,northwestern Himalaya,India: arising threats and need to revive socio-economic values

Surveys were conducted in the cold desert environment of the Lahaul valley in the northwestern Himalaya for assessing the past and present status of Kuth (Saussurea lappa) cultivation. The findings reveal that this age-old practice now is in bottleneck. Main factors responsible for this setback to the species were the lengthy cultivation cycle, small land holdings, and even fluctuating and relatively low market prices. Owing to these constraints farmers have now started replacing cultivation of this threatened herb with pea (Pisum sativum L.), potato (Solanum tuberosum L.) and hop (Humulus lupulus L.). These crops obtained popularity due to comparatively more economic returns as well as their easy adaptability to the short growth season of the cold desert environment. Kuth cultivation in this region is among the interesting examples of domesticating wild medicinal herb by some innovative farmers during the 1920s. However, in the recent past farmers have been less interested to continue this practice due to its larger cultivation cycle, more profits with cash crops like pea and potato, and permit formalities at the time of export from the valley. In addition to being the oldest cash crop in the cold desert environment, Kuth is an endangered medicinal herb that has to be conserved on a priority basis. This study attempts to find out potential measures such as regular revision of market rates, development of existing uncultivable land under medicinal plant cultivation and strengthening the marketing network through establishment of federations of farmers at village level to revive cultivation of this important species.     

Antioxidant and antiproliferative activity of curcumin semicarbazone

A new semicarbazone derivative of curcumin (CRSC) was synthesized and examined for its antioxidant, antiproliferative, and antiradical activity and compared with those of curcumin (CR). The antioxidant activity was tested by their ability to inhibit radiation induced lipid peroxidation in rat liver microsomes. The antiproliferative activity was tested by studying the in vitro activity of CRSC against estrogen dependant breast cancer cell line MCF-7. Kinetics of reaction of (2,2'-diphenyl-1-picrylhydrazide) DPPH, a stable hydrogen abstracting free radical was studied to measure the antiradical activity using stopped-flow spectrophotometer. Finally one-electron oxidized radicals of CRSC were generated and characterized by pulse radiolysis. The results suggest that the probable site of attack for CRSC is both the phenolic OH and the imine carbonyl position. CRSC shows efficient antioxidant and antiproliferative activity although its antiradical activity is less than that of CR.     

Combination Treatment with Resveratrol and Sulforaphane Induces Apoptosis in Human U251 Glioma Cells

Resveratrol is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Sulforaphane belongs to the family of isothiocyanates and is highly enriched in cruciferous vegetables. Our previous study showed that resveratrol, when used at high concentrations, inhibited cell proliferation, caused the cell cycle arrest and induced apoptotic cell death in glioma cells. In the current study, we tested the effect of combination treatment with resveratrol and sulforaphane, when both were used at low concentrations, on cell proliferation, migration and death in human U251 glioma cells. Our study shows that combination treatment with resveratrol and sulforaphane inhibits cell proliferation and migration, reduces cell viability, induces lactate dehydrogenase release, decreases pro-survival Akt phosphorylation and increases caspase-3 activation. The use of combination of bioactive food components, such as resveratrol and sulforaphane, may be a viable approach for the treatment of glioma.     

Analysis of beta-carotene hydroxylase gene cDNA isolated from the American oil-palm (Elaeis oleifera) mesocarp tissue cDNA library

It is well known that the nutritional quality of the American oil-palm (Elaeis oleifera) mesocarp oil is superior to that of African oil-palm (Elaeis guineensis Jacq. Tenera) mesocarp oil. Therefore, it is of important to identify the genetic features for its superior value. This could be achieved through the genome sequencing of the oil-palm. However, the genome sequence is not available in the public domain due to commercial secrecy. Hence, we constructed a cDNA library and generated expressed sequence tags (3,205) from the mesocarp tissue of the American oil-palm. We continued to annotate each of these cDNAs after submitting to GenBank/DDBJ/EMBL. A rough analysis turned our attention to the beta-carotene hydroxylase (Chyb) enzyme encoding cDNA. Then, we completed the full sequencing of cDNA clone for its both strands using M13 forward and reverse primers. The full nucleotide and protein sequence was further analyzed and annotated using various Bioinformatics tools. The analysis results showed the presence of fatty acid hydroxylase superfamily domain in the protein sequence. The multiple sequence alignment of selected Chyb amino acid sequences from other plant species and algal members with E. oleifera Chyb using ClustalW and its phylogenetic analysis suggest that Chyb from monocotyledonous plant species, Lilium hubrid, Crocus sativus and Zea mays are the most evolutionary related with E. oleifera Chyb. This study reports the annotation of E. oleifera Chyb. ABBREVIATIONS: ESTs - expressed sequence tags, EoChyb - Elaeis oleifera beta-carotene hydroxylase, MC - main cluster.     

Immunogenicity of iron-regulated outer membrane proteins of Pasteurella multocida B:2 in mice model

The present study was conducted to investigate the role of iron-regulated outer membrane proteins (IROMP) of Pasteurella multocida B:2 in mice as potential immunogens. Outer membrane proteins extracted from P. multocida B:2 grown under normal (OMP) and iron-deficient (IROMP) conditions were subjected to discontinuous SDS-PAGE. Nine polypeptides of MW ranging from 85.1 to 16.7 kDa from OMP preparations and two additional polypeptides of MW 95.4 and 89.1 kDa from IROMP preparations were observed with bands of MW 37.2 and 34.7 kDa as major proteins. Mice were immunized twice with OMP, IROMP-enriched fractions and whole cell lysate (WCL) via subcutaneous route at day 0 and 21. Antibody titers were determined from sera collected at weekly interval and protection was studied against challenge using 10(2) cfu of P. multocida two weeks after secondary immunization via intranasal and subcutaneous routes. IROMP and OMP immunized mice provoked significant antibody responses and IROMP induced higher antibody responses. IROMP and OMP immunized mice showed protection (100%) upon intranasal challenge and a protection (84%) following subcutaneous challenge as compared to high mortality (84%) in control mice. These results indicate that OMP enriched with IROMP fractions can be superior means of immunization.