Enzymatic formation of potential anticancer and antiviral inosine analogues

Theoretically, inosine analogues should act as effective inhibitors of tumor cell proliferation and viral replication. To acquire a broad spectrum of new candidate inosine analogues, a rapid, facile, quantitative and stereoselective method for deaminating potential antitumor and antiviral adenine analogues previously synthesized in our laboratory was developed. A novel 5'-adenylic acid deaminase, with relaxed substrate requirements, from Aspergillus species was utilized to deaminate four hexofuranosyladenine nucleosides and five adenine nucleoside dialdehydes to their corresponding inosine analogues. The fastest rates of deamination for the hexofuranosyl nucleosides were for the compounds where the vicinal hydroxyl groups on the sugars are oriented in the erythro configuration. For rapid deamination of the adenine nucleoside dialdehydes, the R configuration at the proximal carbon atom is preferred, while the nature of the group on the distal carbon atom has no significant effect on the rate or extent of deamination.

Synthesis and antileukemic activity of certain D-fucopyranosyl nucleosides

Based upon previously discovered antileukemic properties of 9-beta-D-fucopyranosyladenine (1) in cell culture, four new nucleosides containing naturally occurring bases have been prepared from D-fucose. alpha-D-Fucopyranose tetraacetate was condensed with the silylated bases in either acetonitrile or 1,2-dichloroethane with tin(IV) chloride as the catalyst. The intermediate blocked nucleosides were obtained in crystalline form and deacetylated with methanolic sodium methoxide. 1-beta-D-Fucopyranosyluracil (8), 1-beta-D-fucopyranosylthymine (9), 1-beta-D-fucopyranosylcytosine (10) as the hydrochloride salt, and 7-beta-D-fucopyranosylguanine (11) were crystallized, and their structures were verified by spectroscopic techniques. Nucleosides 8 and 9 had only borderline activity against leukemia L1210 cells grown in culture, whereas nucleoside 11 had activity equal to 1. However, nucleoside 10 proved to be twice as active as either 1 or 11. The antileukemic activity, which was due to the inhibition of cell division, was reversible by transfer of the arrested cells to fresh media or by the addition of cytidine.

Antiproliferative activity of purine nucleoside dialdehydes against leukemia L1210 in vitro

Sixteen purine nucleoside dialdehydes were assayed for antiproliferative activity against murine leukemia L1210 grown in vitro. These compounds either lacked the terminal hydroxymethyl group that is necessary in most cases for phosphorylation, and/or had stereochemically different configurations at one or two positions, or had some alteration in the purine ring structure. Among the latter were two lipophilic N6-benzyladenine containing dialdehydes, and two nucleoside dialdehydes with a bromine atom at C-8 of the purine. These nucleoside dialdehydes, unlike most clinically useful anticancer nucleosides, did not require enzymatic phosphorylation to become activated. The most interesting agent in this group of compounds was the lipophilic nucleoside dialdehyde obtained from N6-benzyladenosine after periodate oxidation. It had an IC50 of 1.0 +/- 0.2 microM, and appears to function by limiting the formation of deoxyguanosine diphosphate (dGDP) by inhibition of ribonucleoside diphosphate reductase, the rate limiting step in the biosynthesis of deoxyribonucleotides.

Origin and fate of IgE-bearing lymphocytes. II. Modulation of IgE isotype expression on Peyer's patch cells by feeding with certain bacteria and bacterial cell wall components or by thymectomy

Mechanisms regulating the appearance of sIgE+ B lymphocytes appear to be lacking in adult germfree (GF) rats in that their Peyer's patches (PP) contain high numbers of cells with sIgE (approximately 15% of total cells), one-half of which simultaneously express sIgA, whereas sIgE+ cells are absent from PP of conventional rats (less than 1%). GF rat PP also contain elevated numbers of sIgA+ cells and decreased numbers of sIgM+ cells, with elevated numbers of sThy-1+ RT 7.1+ Ig- T cells, and reduced numbers of sThy-1- RT 7.1+ Ig- T cells. The cellular composition of PP of GF rats was converted to that resembling a conventional rat within 18 h after either 1) use of standard (unautoclaved) food; 2) feeding with certain bacteria (Clostridium difficile, Corynebacterium pseudodiphtheriticum, Mycobacterium tuberculosis, and Klebsiella pneumoniae), in either live or heat-killed, but not autoclaved form; or with certain bacterial cell wall components: murein (peptidoglycan), and its synthetic derivatives, muramyltripeptide phosphatidylethanolamine and desmethyl-muramyldipeptide, but not with LPS, core lipid A or lipoprotein; there was no effect if any bacterial cell wall component was injected i.v.; or 3) thymectomy. Each procedure resulted in elimination of sIgE+ B cells and normalization of the other surface isotypes, and loss of sThy-1+ RT 7.1+ Ig- T cells and normalization of sThy-1- RT 7.1+ Ig- T cells. Irrespective of treatment, no sIgE+ cells were detected in bone marrow, thymus, other lymphoid organs or blood, excluding the possibility that the elimination of these cells from PP was associated with their redistribution to other sites. Thus, exposure to gut flora and bacterial peptidoglycan components may have resulted in IgE isotype switching, either directly or through the mediation of accessory and/or sThy-1+ RT 7.1+ regulatory T cells. The sites in which sIgE+ B cells are down-regulated appear to be PP.

Origin and fate of IgE-bearing lymphocytes. II. Modulation of IgE isotype expression on Peyer's patch cells by feeding with certain bacteria and bacterial cell wall components or by thymectomy

Mechanisms regulating the appearance of sIgE+ B lymphocytes appear to be lacking in adult germfree (GF) rats in that their Peyer's patches (PP) contain high numbers of cells with sIgE (approximately 15% of total cells), one-half of which simultaneously express sIgA, whereas sIgE+ cells are absent from PP of conventional rats (less than 1%). GF rat PP also contain elevated numbers of sIgA+ cells and decreased numbers of sIgM+ cells, with elevated numbers of sThy-1+ RT 7.1+ Ig- T cells, and reduced numbers of sThy-1- RT 7.1+ Ig- T cells. The cellular composition of PP of GF rats was converted to that resembling a conventional rat within 18 h after either 1) use of standard (unautoclaved) food; 2) feeding with certain bacteria (Clostridium difficile, Corynebacterium pseudodiphtheriticum, Mycobacterium tuberculosis, and Klebsiella pneumoniae), in either live or heat-killed, but not autoclaved form; or with certain bacterial cell wall components: murein (peptidoglycan), and its synthetic derivatives, muramyltripeptide phosphatidylethanolamine and desmethyl-muramyldipeptide, but not with LPS, core lipid A or lipoprotein; there was no effect if any bacterial cell wall component was injected i.v.; or 3) thymectomy. Each procedure resulted in elimination of sIgE+ B cells and normalization of the other surface isotypes, and loss of sThy-1+ RT 7.1+ Ig- T cells and normalization of sThy-1- RT 7.1+ Ig- T cells. Irrespective of treatment, no sIgE+ cells were detected in bone marrow, thymus, other lymphoid organs or blood, excluding the possibility that the elimination of these cells from PP was associated with their redistribution to other sites. Thus, exposure to gut flora and bacterial peptidoglycan components may have resulted in IgE isotype switching, either directly or through the mediation of accessory and/or sThy-1+ RT 7.1+ regulatory T cells. The sites in which sIgE+ B cells are down-regulated appear to be PP.

Antiproliferative effects of 4',5'-unsaturated adenine nucleosides on leukemia L1210 cells in vitro

Several 4',5'-unsaturated adenine nucleosides were shown to have antiproliferative activity against L1210 leukemia cells in vitro. The active nucleosides were cytotoxic to the L1210 cells as demonstrated by Trypan Blue uptake. The cytotoxicity was not induced by alterations in the ribonucleoside and deoxyribonucleoside triphosphate levels of the L1210 cells.

A tumor growth inhibitory factor and a tumor growth promoting factor isolated from unfertilized ova of shad (Alosa sapidissima)

In the present study, a cytostatic tumor growth inhibitory peptide and a tumor growth promoting peptide with molecular weights of 20,000-30,000 Da have been identified in the supernatant fraction of unfertilized ova from Shad. The factors can be separated by gel chromatography, thus indicating that the factors are individual molecules. Both of the factors are nondialyzable, heat stable, and resistant to trypsin digestion and periodate oxidation.

Mercaptoethanol protects glutathione depleted cells

Buthionine sulfoximine depleted the glutathione (GSH) level of mouse lymphoma L1210A cells in culture to 6% of control and killed the cells within 48 hours in medium supplemented with fetal calf serum or bovine serum albumin. Mercaptoethanol or alpha-thioglycerol but not GSH or cysteine added to the medium protected the cells from the effect of GSH depletion. Horse serum was also protective, and this effect was removed by dialysis over 65 hours and could not be restored by adding GSH. Mercaptoethanol alone had a protective action in the dialyzed sera. The results suggest that mercaptoethanol may act independently and perform the functions of GSH.

Preparation and antileukemic screening of some new 6'-deoxyhexopyranosyladenine nucleosides

9-beta-D-Fucopyranosyladenine (1) has weak antileukemic activity against L1210 cells grown in culture. Several new 6'-deoxyhexopyranosyladenine nucleosides were synthesized by standard procedures and assayed for activity. The new nucleosides were 9-(6-deoxy-beta-D-glucopyranosyl)adenine (2), 9-(6-deoxy-beta-D-allopyranosyl)adenine (3), 9-(6-deoxy-alpha-L-talopyranosyl)adenine (4), 9-alpha-D-rhamnopyranosyladenine (5), and 9-(6-deoxy-alpha-L-idopyranosyl)adenine (6). In addition, 9-(6-deoxy-alpha-L-sorbofuranosyl)adenine (7) was isolated from the same preparation as 6. None of the new nucleosides 2-7 had activity against L1210 cells in culture. A number of other known nucleosides related in structure to 1 were also tested for activity. One of these, 9-alpha-L-arabinopyranosyladenine, had activity, but was significantly weaker than 1.

Correlation of histochemical and biochemical analyses of androgen binding in prostatic cancer: relation to therapeutic response

A histochemical technique for the detection of androgen binding in prostatic cancer was performed on specimens from 108 patients and compared with a biochemical method in a double blind study of 77. Statistical analyses showed a significant agreement between the two assay systems for the qualitative and quantitative presence or absence of specific androgen binding, as well as for the subcellular localization of binding in nucleus and/or cytoplasm. Although the number of cases studied was too small for statistical analysis, there appeared to be good correlation between histochemical androgen binding results and clinical response, or lack of response to hormonal manipulation in 20 patients with State C and Stage D carcinoma. No correlation was evident between androgen binding and tumor grade or clinicopathologic stage of disease of either histochemistry or biochemistry.

Immunohistologic and histochemical methods for detection of steroid binding in breast cancer: a reappraisal

A review of the current literature on immunohistologic and histochemical methods for the detection of steroid hormone binding sites in breast cancer, reveals that many, but not all of the criteria for establishing hormone-receptor binding interactions have been met. These include tissue specificity, binding between labeled ligands and soluble receptor in vitro, correlations between histochemical and biochemical assays, as well as between histologic procedures and tumor hormone responsiveness. However, histochemical binding phenomena do not appear to follow classical receptor dogma in regard to the concentration of ligand required, or specificity of binding as determined by competitive binding assays. It is concluded that these histologic techniques may be detecting classical receptor that may be reacting differently than would be expected from biochemical analyses, Types II and III binding sites, and/or organelle and membrane-bound receptors. Certainly no current method should presently be promoted as a laboratory method for the detection of classical receptor. New immunocytologic procedures employing specific, antireceptor sera currently under development, may obviate many of the criticisms leveled against earlier methods.

Histochemical assay of estrogen and progesterone receptors in breast cancer: correlation with biochemical assays and patients' response to endocrine therapies

Estrogen (ER) and progesterone (PgR) receptors were assayed by histochemistry in primary, recurrent, and metastatic breast cancer. Ligand-conjugates composed of 17 beta-estradiol and 11 alpha-hydroxyprogesterone covalently linked to bovine serum albumin and labelled with fluorescein isothiocyanate were employed. Results were compared with those of conventional biochemical receptor assays and correlated for ER in 92% of 314 tumors and for PgR in 86% of 86 specimens. ER and PgR determinations by both assay systems were correlated with clinical response to various endocrine therapies in 40 women with Stage IV disease. The histochemical assay enabled successful prediction of response in 80% of cases including eight which could not be fully analyzed biochemically.

Histochemical analyses of steroid hormone receptors in breast and prostatic carcinoma

Histochemical analyses estrogen (ER) and progesterone (PgR) receptors in breast cancer were statistically correlated with results of dextran-coated charcoal (DDC) and sucrose gradient assays. Correlated for ER was 91% of 363 cases, and for PgR 88% of 255 specimens. Breast cancer ER/PgR positivity by histochemistry correlated with a favorable clinical response to endocrine therapies in 72% of 25 cases, while ER/PgR negativity correlated with a lack of response in 96% of 22 cases with Stage IV disease. Nuclear ER/PgR correlated with a poor response to therapy in 8 of 12 patients. An in vitro technique to detect nuclear translocation of ER revealed two groups of ER positive cases, with 11 of 17 exhibiting translocation and 6 not displaying translocation. In prostatic carcinoma, 72% of 65 men were positive for ER and/or androgen receptor. Comparison of specimens obtained without and with electrocautery revealed a preponderance of nuclear binding in the latter, suggesting heat-induced nuclear translocation of receptor. coumestrol, a naturally fluorescent, entirely unaltered estrogen was also used for histochemical detection of ER. Results correlated with ER by DCC in 87% of 61 breast cancers. Coumestrol was additionally used to visually observe receptor and nuclear translocation of ER in intact whole cells in culture.

An improved histochemical method for detection of estrogen receptors in mammary cancer. Comparison with biochemical assay

Unselected, consecutive surgical specimens from 120 women with cancer of the breast were subjected to histochemical assay for the presence of estrogen receptor. A fluoresceinated bovine serum albumin--estradiol conjugate was used that linked estradiol at position 17 and contained 5 mol fluorescein and 4 mol estradiol per mole albumin. Simultaneous competitive binding studies with excess unlabeled estradiol, diethylstilbestrol, and the antiestrogen nitromifene citrate were regularly performed. Results were compared to those obtained by the dextran-coated charcoal receptor assay. Three specimens were necrotic, two others thawed, and two lacked sufficient protein for biochemical analysis. One specimen did not contain tumor, and 11 others showed a predominant nuclear staining pattern. Nuclear receptor was not assayed biochemically. Comparison of results in the remaining 101 cases showed agreement in 92%. The precedure is uncomplicated, economical, and could be performed and interpreted in any pathology laboratory.

Histochemistry of steroid receptors in breast cancer: an overview

Immunofluorescence and a new histochemical technique were employed to assay 226 breast cancer specimens for estrogen receptor. Results showed an overall correlation of 91 percent when compared to those of biochemical assays. The histochemical technique is rapid, easy to perform and reveals the same parameters as does immunofluorescence without the need for antiserum. Tumor cell receptor heterogeneity and location of receptor in cytoplasm or nucleus is readily defined by both methods. These histologic tests should prove to be useful in extending the availability of estrogen receptor analysis to all patients with breast cancer.

Histochemistry of steroid receptors in prostatic diseases

Tissue obtained from 55 men with prostatic disease was assayed for estrogen and androgen receptors by a newly developed histochemical technique. The material studied consisted of 45 specimens of benign nodular prostatic hyperplasia and 10 specimens of prostatic adenocarcinoma. The results obtained were compared to those of parallel biochemical assays in 17 cases and successfully correlated in 85 percent. The new procedure is rapid, inexpensive and accurate, allowing for the detection of receptor in cytoplasm and/or nucleus and evaluation of receptor heterogeneity. The histochemical method may offer an alternate to biochemical assay of prostatic tissue as contamination with steroid binding globulins does not appear to be a problem at this time.

A histochemical technique for evaluation of progesterone receptors in breast cancer

A histochemical method for the detection and localization of progesterone receptors in human breast cancer has been developed employing a fluorescein labeled conjugate of bovine serum albumin linked to a progestin as the binding hormone. Considerable tumor cell receptor heterogeneity was apparent and nuclear binding was frequently noted. The results of the new assay correlated with those obtained by dextran-coated charcoal assay in 91 per cent of specimens.

Detection of androgen and estrogen receptors in human prostatic carcinoma and hyperplasia by fluorescence microscopy

The histochemical detection of androgen and estrogen receptors in human prostatic tissue was achieved employing fluorescein labeled conjugates of bovine serum albumin linked to testosterone and estradiol. Results were compared to those of dextran-coated charcoal and protamine sulfate assays and correlated in 85% of specimens. Early findings include a relatively uniform distribution of receptor in hyperplastic epithelium in contrast to marked tumor cell receptor heterogeneity in cancer. Location of receptor in nucleus and/or cytoplasm was readily determined.

Production of autoinhibitory factors by mouse lymphoma cells in vitro and its relationship to thiol dependence

Five different kinds of mouse lymphoma cells conditioned culture medium so that it became inhibitory to thiol-dependent cells but not to thiol-independent cells. Conditioning was rapid and appeared to be complete in 1-3 hr. The inhibitory effects could be reversed by concentrations of 2-mercaptoethanol higher than those usually required for growth promotion. Inhibitory factors were concentrated by ultrafiltration and chromatography on Sephadex G-10 which showed their apparent molecular weights to be 300-600. The factors were stable at 100 degrees and to proteases but were inactivated (after reduction) by iodoacetamide, indicating that they may be thiols or disulfides.

Immunofluorescent detection of estrogen receptors in breast cancer. Comparison with dextran-coated charcoal and sucrose gradient assays

Biopsy specimens from 106 women with primary operable, recurrent or metastatic breast cancer were analyzed in a double blind study designed to compare the results of a new fluorescent antibody method for detection of estrogen receptors with estrogen receptors measured biochemically with dextran-coated charcoal and sucrose gradient assay techniques. Assay results correlated in 89.4% of tumors analyzed, and molecular receptor forms (8S and 4S) were accurately predicted in 94.7% of neoplasms studied. Divergent results most often occurred in specimens sparsely populated with malignant cells. The new technique permitted recognition of possible sources of false negative results such as necrosis, absence of tumor and, on occasion, estrogen bound in vivo. It was possible to analyze by the immunofluorescence method two specimens of insufficient size for biochemical assay.

Isolation of phosphorylated acid chloroform/methanol-soluble proteins from live frog muscle

About 6-7% of the total proteins from trichloroacetic acid-washed and freeze-dried frog muscle could be extracted with acid chloroform/methanol. Three of these proteins were found to be phosphorylated in the live frog. They were purified to apparent homogeneity by gel chromatography and preparative gel electrophoresis. The apparent molecular weights, determined by sodium dodecyl sulfate gel electrophoresis, were 34 000, 19 000 and 10 000. Each phosphorylated protein contained 3 mol of a covalently bound neutral sugar but they did not contain any tightly bound lipids. All three proteins incorporated 32P into serine phosphate. The 10 000 dalton protein, which had the highest specific radioactivity contained an unusually high proportion of serine, 14% of the total amino acids. It also did not stain with Coomassie Blue.

Isolation of a 32P-labeled polypeptide of low molecular weight from phosphorylated human erythrocyte membranes

The incorporation of 32P into well washed human erythrocyte membranes was studied in a medium containing [gamma-32P]ATP, Mg2+, and EGTA. Following phosphorylation, the membranes were completely solubilized in 1% sodium dodecyl sulfate and subjected to gel electrophoresis in dodecyl sulfate polyacrylamide. A large incorporation of radioactivity was observed in a band which migrated faster than component 7 (nomenclature of T. L. Steck, (1972), J. Mol. Biol. 66, 295) but slower than the bromophenol blue tracking dye, and did not stain with Coomassie Blue. Isolation of this band by preparative gel electrophoresis revealed that 41% of the radioactivity was associated with a 32P-labeled polypeptide. This polypeptide was further purified by gel chromatography on Sephadex LH-20 in chloroform-methanol-HCl, and Bio-Gel A 1.5m in dodecyl sulfate. Its amino acid composition is characterized by a high content of acidic residues. The calculated minimal molecular weight is 15084. Based upon the recovery of amino acids, the polypeptide fraction comprises at least 1.8% by weight of the total erythrocyte membrane proteins. An apparent molecular weight of 15000 was estimated by gel chromatography in dodecyl sulfate, while a range of 14000-16000 was estimated by electrophoresis in dodecyl sulfate polyacrylamide. The state of phosphorylation of this peptide may reflect a physiological function in the intact red cell.