Inhibitory Effects of Salinomycin on Cell Survival,Colony Growth,Migration, and Invasion of Human Non-Small Cell Lung Cancer A549 and LNM35: Involvement of NAG-1

A major challenge for oncologists and pharmacologists is to develop more potent and less toxic drugs that will decrease the tumor growth and improve the survival of lung cancer patients. Salinomycin is a polyether antibiotic used to kill gram-positive bacteria including mycobacteria, protozoans such as plasmodium falciparum, and the parasites responsible for the poultry disease coccidiosis. This old agent is now a serious anti-cancer drug candidate that selectively inhibits the growth of cancer stem cells. We investigated the impact of salinomycin on survival, colony growth, migration and invasion of the differentiated human non-small cell lung cancer lines LNM35 and A549. Salinomycin caused concentration- and time-dependent reduction in viability of LNM35 and A549 cells through a caspase 3/7-associated cell death pathway. Similarly, salinomycin (2.5–5 µM for 7 days) significantly decreased the growth of LNM35 and A549 colonies in soft agar. Metastasis is the main cause of death related to lung cancer. In this context, salinomycin induced a time- and concentration-dependent inhibition of cell migration and invasion. We also demonstrated for the first time that salinomycin induced a marked increase in the expression of the pro-apoptotic protein NAG-1 leading to the inhibition of lung cancer cell invasion but not cell survival. These findings identify salinomycin as a promising novel therapeutic agent for lung cancer.     

Utilization of acrylonitrile by bacteria isolated from petrochemical waste waters

A bacterium, utilising acrylonitrile as a sole source of carbon and nitrogen, was isolated from Indian Petrochemical Corporation Limited (IPCL) waste waters and identified as Arthrobacter sp. This strain could also utilize acetonitrile, acetamide and acrylamide individually as a source of carbon and nitrogen. The metabolic studies with the whole cells indicated the sequential conversion of the nitrile to the respective amide and then to the respective acid and ammonia. The rate of nitrile hydrolysis was slower than the corresponding amide hydrolysis. Acrylic acid, the end product of acrylonitrile breakdown, did not support the growth when provided as a carbon source.     

Ethanol and sugar tolerance of Candida shehatae

Summary Candida shehatae ATCC 22984 fermented solutions of up to 260 g/L sugars derived by hydrolysis of whole barley. These solutions contained hexose: pentose 7030, the hexose being mainly glucose from the barley starch and the pentose being mainly xylose. At sugar concentrations of 180 g/L, fermentation was complete in 72 h, yielding 84 g/L ethanol, 0.47 g ethanol/g sugar. At 260 g/L, fermentation ceased when ethanol concentration reached 100 g/L, but resumed when the ethanol was removed by vacuum distillation, to yield finally 0.50 g ethanol/g sugar.     

Immune stimulation may contribute to enhanced progression of SIV induced disease in rhesus macaques

Abstract: A number of rhesus macaques experimentally infected with SIV isolates such as SIVmac251, fail to seroconvert, develop high plasma viremia and die rapidly (within 6–7 months p.i.). We hypothesized that such rapid progression is a result of a state of hyperimmune activation and concomitant immune suppression of these animals at the time of virus challenge. In efforts to test the hypothesis that immune activation leads to rapid progression of lentivirus-induced disease, adult rhesus macaques were infected with SIVmac251 and received an alternate monthly schedule of repeated immunization with allogeneic cells, keyhole limpet hemocyanin and tetanus toxoid (group I). For purposes of controls, a group of monkeys was infected with the same pool and dose of virus but were not immunized (group II) and a group was immunized with the same schedule of multiple antigens as group I but were not infected with SIV (group III). All the animals in group I (n ? 3) either failed to seroconvert or developed very low levels of SIV antibodies, had high plasma p27 defined antigenemia, and died within 8 months (2/3 died within 4 months). Of the animals in group II (n = 8), two patterns emerged as we had noted before. One subgroup (3 animals), displayed the same profile as group I (failure to fully seroconvert, high p27 levels and death by 8 months), whereas the other subgroup (5 animals) seroconverted, had low plasma p27 levels, and survived past 11 months (2/5 still alive past 22 months). All 3 animals in group III remained healthy. The data provided herein suggest that either experimental or natural (due to factors not clear at present) immune stimulation may lead to accelerated lentivirus induced disease progression most likely due to immune suppression and has implications for the understanding of the mechanisms for the rate of disease progression in human HIV-1 infection.     

Molecular Determinants of the Cellular Entry of Asymmetric Peptide Dendrimers and Role of Caveolae

Caveolae are flask-shaped plasma membrane subdomains abundant in most cell types that participate in endocytosis. Caveola formation and functions require membrane proteins of the caveolin family, and cytoplasmic proteins of the cavin family. Cationic peptide dendrimers are non-vesicular chemical carriers that can transport pharmacological agents or genetic material across the plasma membrane. We prepared a panel of cationic dendrimers and investigated whether they require caveolae to enter into cells. Cell-based studies were performed using wild type or caveola-deficient i.e. caveolin-1 or PTRF gene-disrupted cells. There was a statistically significant difference in entry of cationic dendrimers between wild type and caveola-deficient cells. We further unveiled differences between dendrimers with varying charge density and head groups. Our results show, using a molecular approach, that (i) expression of caveola-forming proteins promotes cellular entry of cationic dendrimers and (ii) dendrimer structure can be modified to promote endocytosis in caveola-forming cells.     

N-glycosylation and in vitro enzymatic activity of human recombinant tissue plasminogen activator expressed in Chinese hamster ovary cells and a murine cell line

To probe the effects of N-glycosylation on the fibrin-dependent plasminogenolytic activity of tissue-type plasminogen activator (t-PA), we have expressed a human recombinant t-PA (rt-PA) gene in Chinese hamster ovary (CHO) cells and in a murine C127 cell line. The resulting rt-PA glycoproteins were isolated and their associated N-linked oligosaccharide structures determined by using a combination of high-resolution Bio-Gel P-4 gel filtration chromatography, sequential exoglycosidase digestion, and methylation analysis. The results show that CHO rt-PA is N-glycosylated differently from murine C127 derived rt-PA. Further, both rt-PA's are N-glycosylated differently from t-PA derived from a human colon fibroblast and the Bowes melanoma cell line (Parekh et al., 1989), confirming that N-glycosylation of the human t-PA polypeptide is cell-type-specific. Both CHO and murine rt-PA were fractionated on lysine-Sepharose chromatography. The N-glycosylation of the major forms was analyzed and their fibrin-dependent plasminogenolytic activity determined by using an indirect amidolytic assay with Glu-plasminogen and a chromogenic plasmin substrate. The results suggest that the various forms of rt-PA differ from one another with respect to the kinetics of their fibrin-dependent activation of plasminogen. Together, these data support the notion (Wittwer et al., 1989) that N-glycosylation influences the fibrin-dependent catalytic activity of t-PA and that t-PA when expressed in different cell lines may consist of kinetically and structurally distinct glycoforms.     

Phytase from Klebsiella Sp. No. PG-2: purification and properties

A phytase (EC 3.1.3.8) was extracted from rat intestinal bacterium, Klebsiella Sp. No. PG.-2, and purified 50-fold by ammonium sulphate fractionation, ion-exchange chromatography and gel filtration. The enzyme is inducible in nature. The pH optimum was at 6.0 for all the inositol phosphates studied and this characterized the enzyme as an acid phosphohydrolase. Of a range of potential substrates tested, only p-nitrophenyl phosphate alongwith the inositol phosphates was hydrolyzed. It exhibits a Km of 2.0 mM; temperature optimum of 37 degrees C and energy of activation 9,120 cal/mole for all the inositol phosphates studied. The activity was inhibited by Ag2+, Hg2+, Cu2+, fluoride and high substrate concentration.     

In vitro comparison of ceftazidime,aztreonam, cefpirome,gentamicin, imipenem,enoxacin, and ticarcillin plus clavulanic acid against 108 strains ofPseudomonas maltophilia

Pseudomonas maltophilia is an uncommon cause of hospital-acquired infection and is resistant to most of the antimicrobial agents used in the treatment of gram-negative infections. Susceptibility of 108 isolates ofP. maltophilia to ceftazidime, aztreonam, defpirome, gentamicin, imipenem, enoxacin, and ticarcillin plus clavulanic acid was determined by an agar dilution method. The isolates were in general resistant to the antibiotics. Imipenem and cefpirome were not active at clinically achievable levels. Of the isolates, 20% were susceptible to 16 g/ml ceftazidime, 53% were susceptible to 4 g/ml enoxacin, 10% were susceptible to 4 g/ml gentamicin, and 25% were susceptible to 64 g/ml ticarcillin plus 2 g/ml clavulanic acid.