Tyrphostins reduce chemotherapy-induced intestinal injury in mice: assessment by a biochemical assay.

Intestinal injury that results from chemotherapy belongs to the major factors of dose-limitation in tumour therapy. The tyrphostins AG1714 and AG1801 reduce cisplatin and 5-FU-induced small intestinal mucosal damage, using a quantitative biochemical assay. The assay is based on the determination of the enzymatic activity of gamma-glutamyl transpeptidase, a marker of the brush border epithelium of the small intestine.

Allicin stimulates lymphocytes and elicits an antitumor effect: a possible role of p21ras.

Allicin, the main organic allyl sulfur component in garlic, exhibits immune-stimulatory and antitumor properties. Allicin stimulated [(3)H]thymidine incorporation in mouse splenocytes and enhanced cell-mediated cytotoxicity in human peripheral mononuclear cells. Multiple administration (i.

Ferrocene-induced lymphocyte activation and anti-tumor activity is mediated by redox-sensitive signaling.

Ferrocene, a stable, synthetic, iron-containing compound induces in vitro and in vivo activation of mouse lymphocytes and macrophages. Ferrocene also has a marked antitumor effect in mice, upon its administration intraperitoneally and in drinking water. Ferrocene's antitumor activity is attributed to its immune-stimulatory property.

4-Nitrobenzylidene malononitrile reduces apoptosis-mediated liver injury in mice.

Background: Apoptosis plays a role in experimental and clinically related liver damage. Inhibitors of tyrosine kinases were shown to modulate apoptosis induced by different agents in various cell types.

Aims: Investigation of the effect of 4-nitrobenzylidene malononitrile (belonging to the tyrphostins family which are selective inhibitors of protein tyrosine kinases) on apoptosis-mediated acute liver injury.

CD4+ T lymphocytes as a primary cellular target for BAT mAb stimulation.

BAT is a monoclonal antibody (mAb) produced against membranes of a human Burkitt lymphoma cell line (Daudi) that was selected for its ability to stimulate lymphocyte proliferation. BAT manifests anti-tumor properties in mice bearing a variety of murine tumors. BAT also induced regression of human tumors inoculated into SCID mice that had been engrafted with human lymphocytes.

Activation of lymphocytes by BAT and anti CTLA-4: comparison of binding to T and B cells.

In this study we compare the binding and immune stimulatory properties of BAT and anti CTLA-4 monoclonal antibodies (mAbs). Both antibodies were previously shown to manifest effective immune responses against tumor cells. We have described that BAT antibody, produced against Daudi, a B lymphoblastoid cell line, binds and activates T cells.

Antibodies to neuroblastoma cell line proteins in patients with schizophrenia.

The presence of antibodies against neural antigens was investigated in the serum of patients with schizophrenia, major depression and normal controls. Different immunological abnormalities, humoral and cellular, were reported in schizophrenia and major depression. The pathogenesis of schizophrenia is multifactorial.

Tyrphostin 4-nitrobenzylidene malononitrile reduces chemotherapy toxicity without impairing efficacy.

In mice, 4-nitrobenzylidene malononitrile (AG1714), which belongs to the tyrphostin family, reduced toxicity induced by doxorubicin and cisplatin without impairing their antitumor efficacy. AG1714 reduced mortality induced by doxorubicin and cisplatin. It prevented, in a dose-dependent manner, cisplatin-induced nephrotoxicity as assessed by measurement of serum creatinine and blood urea nitrogen levels.

A lymphocyte-activating monoclonal antibody induces regression of human tumors in severe combined immunodeficient mice.

Monoclonal antibodies were raised against Daudi B-lymphoblastoid cell line membranes. An mAb (BAT) was selected for its ability to stimulate human and murine lymphocyte proliferation. BAT induced cytotoxicity in human and murine lymphocytes against natural killer cell-sensitive and -resistant tumor cell lines.

Tyrphostin AG 556 improves survival and reduces multiorgan failure in canine Escherichia coli peritonitis.

Tyrosine kinase-dependent cell signaling is postulated to be a pivotal control point in inflammatory responses initiated by bacterial products and TNF. Using a canine model of gram-negative septic shock, we investigated the effect of tyrosine kinase inhibitors (tyrphostins) on survival. Animals were infected intraperitoneally with Escherichia coli 0111: B4, and then, in a randomized, blinded fashion, were treated immediately with one of two tyrphostins, AG 556 (n = 40) or AG 126 (n = 10), or with control (n = 50), and followed for 28 d or until death.

Immune stimulatory and anti-tumor properties of anti-CD3 and BAT monoclonal antibodies: a comparative study.

A novel monoclonal antibody raised to Daudi cell membranes was found to exhibit immune stimulatory and anti-tumor properties. The activity of this antibody (BAT) which also binds T cells was compared to that of anti-CD3. Anti-CD3 reacts with the T cell receptor complex, induces cell proliferation, and cytolytic activity in vitro and also manifests in vivo anti-tumor effect against murine tumors.

Late administration of a lipophilic tyrosine kinase inhibitor prevents lipopolysaccharide and Escherichia coli-induced lethal toxicity.

Septic shock induced by gram-negative bacteria results primarily from excessive stimulation by lipopolysaccharide (LPS) of macrophages to produce tumor necrosis factor (TNF)-alpha and interleukin (IL)-1. The cellular effects of LPS, TNF-alpha, and IL-1 are mediated via tyrosine phosphorylation pathways. A recent report indicated that selective inhibitors of tyrosine kinases, tyrphostins of the AG126 family, protect mice against LPS-induced lethal toxicity in mice.

p21ras as a common signaling target of reactive free radicals and cellular redox stress.

Reactive free radicals have been implicated in mediating signal transduction by a variety of stimuli. We have investigated the role of p21ras in mediating free radical signaling. Our studies revealed that signaling by oxidative agents which modulate cellular redox status, such as H2O2, hemin, Hg2+, and nitric oxide was prevented in cells in which p21ras activity was blocked either through expression of a dominant negative mutant or by treating with a farnesyltransferase inhibitor, as assessed by NF-kappa B binding activity.

Activation of human lymphocytes by a monoclonal antibody to B lymphoblastoid cells; molecular mass and distribution of binding protein.

A novel monoclonal antibody (BAT) to the B-lymphoblastoid cell line activates murine lymphocytes and exhibits a striking antitumor activity in mice. In order to evaluate the potential use of this antibody against human cancer, we have investigated its immuno-stimulatory properties on human peripheral blood lymphocytes (PBL). Our findings demonstrate that BAT mAb induces proliferation and cytotoxicity in human PBL against natural-killer-cell-sensitive and natural-killer-cell-resistant tumor cell lines.

A diagnostic assay for the Wiskott-Aldrich syndrome and its variant forms.

Background: The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disease characterized by severe thrombocytopenia, eczema, and impaired immunity. While the diagnosis is usually straightforward, the syndrome may be expressed in an attenuated form, a phenotype which is difficult to distinguish from other types of congenital thrombocytopenia. Although a molecular-based assay for diagnosis of the spectrum of WAS patients has not been available, recent data indicate that WAS is associated with a specific profile of impaired mitogen responsiveness and suggest that detection of this abnormality may provide a diagnostic marker for all forms of the disease.

Nitric oxide-stimulated guanine nucleotide exchange on p21ras.

The protooncogene p21ras, a monomeric G protein family member, plays a critical role in converting extracellular signals into intracellular biochemical events. Here, we report that nitric oxide (NO) activates p21ras in human T cells as evidenced by an increase in GTP-bound p21ras. In vitro studies using pure recombinant p21ras demonstrate that the activation is direct and reversible.

A monoclonal antibody against a human B lymphoblastoid cell line induces tumor regression in mice.

We have developed a monoclonal antibody (BAT) to Daudi B lymphoblastoid cell line membranes. The antibody was selected for its ability to stimulate lymphocyte proliferation. Splenocytes of BALB/c or C57BL mice given i.

Butyrate-induced differentiation in leukemic myeloid cells - in-vitro and in-vivo studies.

A study of the effects of three differentiating agents, butyric acid, retinoic acid and cytosine arabinoside on proliferation and differentiation of primary cultures, obtained from sixteen patients with myelo-proliferative disorder was conducted. The results showed that BA was an effective inhibitor of cell proliferation and inducer of cytodifferentiation. An acute non-lymphoblastic leukemia patient was treated with sodium butyrate.

Prevention of lipopolysaccharide-induced lethal toxicity by tyrosine kinase inhibitors.

Septic shock results from excessive stimulation of the host immune system, especially macrophages, by lipopolysaccharide (LPS), or endotoxin, which resides on the outer membrane of bacteria. Protein tyrosine kinase inhibitors of the tyrphostin AG 126 family protect mice against LPS-induced lethal toxicity. The protection correlates with the ability of these agents to block LPS-induced production of tumor necrosis factor alpha (TNF-alpha) and nitric oxide in macrophages as well as LPS-induced production of TNF-alpha in vivo.

Novobiocin modulates colchicine sensitivity in parental and multidrug-resistant B16 melanoma cells.

The effect of the antibiotic agent novobiocin on the sensitivity of melanoma cells to colchicine and vinblastine was examined in drug-sensitive and drug-resistant B16 melanoma cells. A cell line COL/R was selected for colchicine resistance. The COL/R cell line (resistant to 80 ng/ml colchicine) was found to possess the multidrug-resistant (MDR) phenotype.

Nitric oxide signaling: a possible role for G proteins.

We have previously reported various inductive effects of nitric oxide on human PBMC. We describe a novel and potentially important mechanism of nitric oxide signaling-through direct activation of guanine nucleotide-binding proteins (G proteins). We have found that nitric oxide treatment of membranes isolated from fresh human PBMC enhances the ability of these membranes to hydrolyze [gamma-32P]GTP and bind [gamma-35S]GTP.

Immune stimulatory and anti-tumour properties of haemin.

IL-2 induces tumour regression in some patients with metastatic disease, but the dose of IL-2 is limited by severe toxicity. Agents that increase the expression of IL-2 receptors in the effector cells could be used to improve the effectiveness of IL-2 in mediating its anti-tumour effect. We have reported that haemin increased the expression of IL-2 receptors in human peripheral blood mononuclear cells (PBMC) and synergized with IL-2 in the induction of mitogenicity, cytotoxicity and cytokine production.

Amino acid alcohols: growth inhibition and induction of differentiated features in melanoma cells.

The effects of a series of D- and L-amino acid alcohols on the proliferation and phenotypic expression of B16 mouse melanoma cells were evaluated. B16 melanoma cells were incubated for different time intervals in the presence of D- or L-phenylalaninol (PHE), D- or L-alaninol (AL), D- or L-leucinol (LE), L-histidinol (HIS), L-tyrosinol (TYR) and L-methioninol (MET). All agents, including the D or L configuration, induced an anti-proliferative effect, although of considerably different magnitude.

Haemin enhancement of glucose transport in human lymphocytes: stimulation of protein tyrosine phosphatase and activation of p56lck tyrosine kinase.

Following our previous observation that haemin is mitogenic for human lymphocytes, we investigated the ability of haemin to enhance glucose uptake in these cells. We found that preincubation of human peripheral-blood mononuclear cells (PBMC) with haemin for 60 min increased up to 5-fold the rate of 2-deoxy-D-[1-3H]glucose uptake by the cells. Actinomycin D and cycloheximide did not inhibit the effect, and cytochalasin B completely blocked it.

Hemin-induced cap formation in lymphocytes: inhibition by protein tyrosine kinase inhibitors.

Hemin, an oxidant which is mitogenic for lymphocytes, was found to induce cap formation for Con A sites in murine and human lymphocytes and for IgG and Thy 1.2 sites in murine lymphocytes. Doses of hemin which induced capping also induced a redistribution of actin to a detergent-insoluble form.