Central IL-1 differentially regulates peripheral IL-6 and TNF synthesis

Centrally given interleukin (IL)-1 is known to induce a rapid rises in blood IL-6. To extend this and to examine the mechanism by which this occurs, the effects of intracerebroventricular (icv) injection of human recombinant IL-1β on mRNA expression of IL-6 and tumour necrosis factor (TNF) in the spleen and liver were examined in rats. Icv injection of IL-1 produced a rapid rise of the tissue mRNA levels of IL-6 and TNF in both organs, prior to and/or in parallel with an increase in their serum levels. Pretreatment with chlorisondamine, a ganglionic blocking agent, inhibited the IL-6 responses, while it had little influence on the TNF responses. The results suggest that brain IL-1 induces peripheral production of IL-6, but not of TNF, through autonomic nervous system activation. Received 27 October 1997; received after revision 15 December 1997; accepted 12 January 1998     

The molecular basis and clinical aspects of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is a classic, but not widely known hereditary trait. Its clinical hallmarks are intestinal hamartomatous polyposis and melanin pigmentation of the skin and mucous membranes. In addition, PJS predisposes to cancer . The most common malignancies are small intestinal, colorectal, stomach and pancreatic adenocarcinomas. Other cancer types that probably occur in excess in PJS families include breast and uterine cervical cancer, as well as testicular and ovarian sex cord tumors. The relative risk of cancer may be as high as 18 times that of the general population, and the cancer patients' prognosis is reduced. Recently, the predisposing locus was mapped to 19p13.3 using a novel method. Subsequently, the causative gene was shown to be LKB1 (a.k.a. STK11), a serine/threonine kinase of unknown function. Although preliminary reports seem to suggest a minor role for LKB1 in sporadic tumorigenesis, further investigations are needed. Received 12 October 1998; received after revision 30 November 1998; accepted 30 November 1998     

Bromelain: biochemistry, pharmacology and medical use

Bromelain is a crude extract from the pineapple that contains, among other components, various closely related proteinases, demonstrating, in vitro and in vivo, antiedematous, antiinflammatory, antithrombotic and fibrinolytic activities. The active factors involved are biochemically characterized only in part. Due to its efficacy after oral administration, its safety and lack of undesired side effects, bromelain has earned growing acceptance and compliance among patients as a phytotherapeutical drug. A wide range of therapeutic benefits has been claimed for bromelain, such as reversible inhibition of platelet aggregation, angina pectoris, bronchitis, sinusitis, surgical traumas, thrombophlebitis, pyelonephritis and enhanced absorption of drugs, particularly of antibiotics. Biochemical experiments indicate that these pharmacological properties depend on the proteolytic activity only partly, suggesting the presence of nonprotein factors in bromelain. Recent results from preclinical and pharmacological studies recommend bromelain as an orally given drug for complementary tumor therapy: bromelain acts as an immunomodulator by raising the impaired immunocytotoxicity of monocytes against tumor cells from patients and by inducing the production of distinct cytokines such as tumor necrosis factor-α, interleukin (Il)-1β, Il-6, and Il-8. In a recent clinical study with mammary tumor patients, these findings could be partially confirmed. Especially promising are reports on animal experiments claiming an antimetastatic efficacy and inhibition of metastasis-associated platelet aggregation as well as inhibition of growth and invasiveness of tumor cells. Apparently, the antiinvasive activity does not depend on the proteolytic activity. This is also true for bromelain effects on the modulation of immune functions, its potential to eliminate burn debris and to accelerate wound healing. Whether bromelain will gain wide acceptance as a drug that inhibits platelet aggregation, is antimetastatic and facilitates skin debridement, among other indications, will be determined by further clinical trials. The claim that bromelain cannot be effective after oral administration is definitely refuted at this time. Received 25 August 2000; received after revision 29 March 2001; accepted 30 March 2001     

Clinical implications of p53 mutations

The ultimate goal of basic cancer research is to provide a theoretical foundation for rational approaches to improve cancer therapy. Our extensive insight into the biology of the p53 tumour suppressor and the clinical behaviour of tumours harbouring p53 mutations indicates that information concerning p53 will be useful in diagnosis and prognosis, and may ultimately produce new therapeutic strategies. At the same time, efforts to understand the clinical implications of p53 mutations have revealed conceptual and technical limitations in translating basic biology to the clinic. The lessons learned from p53 may lay the groundwork for future efforts to synthesize cancer gene function, cancer genetics and cancer therapy.     

Targeting O 6-methylguanine-DNA methyltransferase with specific inhibitors as a strategy in cancer therapy

O ⁶-methylguanine-DNA methyltransferase (MGMT) repairs the cancer chemotherapy-relevant DNA adducts, O ⁶-methylguanine and O ⁶-chloroethylguanine, induced by methylating and chloroethylating anticancer drugs, respectively. These adducts are cytotoxic, and given the overwhelming evidence that MGMT is a key factor in resistance, strategies for inactivating MGMT have been pursued. A number of drugs have been shown to inactivate MGMT in cells, human tumour models and cancer patients, and O ⁶-benzylguanine and O ⁶-[4-bromothenyl]guanine have been used in clinical trials. While these agents show no side effects per se, they also inactivate MGMT in normal tissues and hence exacerbate the toxic side effects of the alkylating drugs, requiring dose reduction. This might explain why, in any of the reported trials, the outcome has not been improved by their inclusion. It is, however, anticipated that, with the availability of tumour targeting strategies and hematopoetic stem cell protection, MGMT inactivators hold promise for enhancing the effectiveness of alkylating agent chemotherapy.     

Production of functional rat liver PSP protein in Escherichia coli

An efficient Escherichia coli expression system for the production of a perchloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGEX-4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-β-D-galactopyranoside (IPTG), the recombinant product was purified by glutathione-Sepharose 4B affinity chromatography. The purified product showed the expected NH₂-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authentic PSP isolated from rat liver. Received 8 October 1998; received after revision 6 November 1998; accepted 6 November 1998     

Evaluation of the anti-angiogenic effect of aloe-emodin

The present study identified aloe-emodin (AE, a hydroxyanthraquinone from Aloe vera and other plants) as a new anti-angiogenic compound with inhibitory effects in an in vivo angiogenesis assay and evaluates its effects on specific key steps of the angiogenic process. AE inhibits endothelial cell proliferation, but this effect is not cell specific, since AE also inhibits tumor cell proliferation. Cell migration and invasion are not remarkably affected by AE. On the other hand, AE has different effects on endothelial and tumor cell gelatinases. Two main targets of the pharmacological action of AE as an anti-angiogenic compound seem to be urokinase secretion and tubule formation of endothelial cells. Finally, AE produces a remarkable photocytotoxic effect on tumor cells. Taken together, our data indicate that AE can behave both as an anti-tumor and an anti-angiogenic compound and suggest that AE could be a candidate drug for photodynamic therapy. Received 7 September 2006; received after revision 17 October 2006; accepted 31 October 2006     

The structure and function of platelet-activating factor acetylhydrolases

Platelet-activating factor acetylhydrolases (PAF-AHs, EC 3.1.1.47) constitute a unique and biologically important family of phospholipase A₂s. They are related to neither the well-characterized secretory nor cytosolic PLA₂s, and unlike them do not require Ca²⁺ for catalytic activity. The distinguishing property of PAF-AHs is their unique substrate specificity they act on the phospholipid platelet-activating factor (PAF), and in some cases on proinflammatory polar phospholipids, from which they remove a short acyl moiety – acetyl in the case of PAF – located at the sn-2 position. Because PAF is found both in the plasma and in the cytosol of many tissues, PAF-acetylhydrolases are equally widely distributed in an animal organism. Recent crystallographic studies shed new light on the complex structure-function relationships in PAF-AHs. Received 15 September 1997; received after revision 23 February 1998; accepted 25 February 1998     

In pre-sterol carrier protein 2 (SCP2) in solution the leader peptide 1 – 20 is flexibly disordered, and residues 21 – 143 adopt the same globular fold as in mature SCP2

The preform of the rabbit sterol carrier protein 2 (pre-rSCP2) was cloned, the uniformly ¹⁵N-labelled protein expressed in Escherichia coli and studied by three-dimensional ¹⁵N-resolved nuclear magnetic resonance spectroscopy. In spite of its low solubility in aqueous solution of only ∼0.3 mM, sequential ¹⁵N and ¹H backbone resonance assignments were obtained for 105 out of the 143 residues. From comparison of the sequential and medium-range nuclear Overhauser effects (NOEs) in the two proteins, all regular secondary structures previously determined in mature human SCP2 (hSCP2) [Szyperski et al. (1993) FEBS Lett. 335: 18–26] were also identified in pre-rSCP2. Near-identity of the backbone ¹⁵N and ¹H chemical shifts and 1 : 1 correspondence of 24 long-range NOEs to backbone amide groups in the two proteins show that the residues 21 – 143 adopt the same globular fold in pre-rSCP2 and mature hSCP2. The N-terminal 20-residue leader peptide of pre-rSCP2 is flexibly disordered in solution and does not observably affect the conformation of the polypeptide segment 21 – 143. Received 11 May 1998; accepted 15 May 1998     

Differential leaf resistance to insects of transgenic sweetgum (Liquidambar styraciflua) expressing tobacco anionic peroxidase

Leaves of transgenic sweetgum (Liquidambar styraciflua) trees that expressed tobacco anionic peroxidase were compared with leaves of L. styraciflua trees that did not express the tobacco enzyme. Leaves of the transgenic trees were generally more resistant to feeding by caterpillars and beetles than wild-type leaves. However, as for past studies with transgenic tobacco and tomato expressing the tobacco anionic peroxidase, the degree of relative resistance depended on the size of insect used and the maturity of the leaf. Decreased growth of gypsy moth larvae appeared mainly due to decreased consumption, and not changes in the nutritional quality of the foliage. Transgenic leaves were more susceptible to feeding by the corn earworm, Helicoverpa zea. Thus, it appears the tobacco anionic peroxidase can contribute to insect resistance, but its effects are more predictable when it is expressed in plant species more closely related to the original gene source. Received 4 March 1998; received after revision 27 April 1998; accepted 30 April 1998     

General anaesthetic actions on ligand-gated ion channels

The molecular mechanisms of general anaesthetics have remained largely obscure since their introduction into clinical practice just over 150 years ago. This review describes the actions of general anaesthetics on mammalian neurotransmitter-gated ion channels. As a result of research during the last several decades, ligand-gated ion channels have emerged as promising molecular targets for the central nervous system effects of general anaesthetics. The last 10 years have witnessed an explosion of studies of anaesthetic modulation of recombinant ligand-gated ion channels, including recent studies which utilize chimeric and mutated receptors to identify regions of ligand-gated ion channels important for the actions of general anaesthetics. Exciting future directions include structural biology and gene-targeting approaches to further the understanding of general anaesthetic molecular mechanisms. Received 10 December 1998; received after revision 22 February 1999; accepted 23 February 1999     

Neuroprotective effects of <Emphasis Type="Italic">Ginkgo biloba</Emphasis> extract

Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute to its neuroprotective and vasotropic effects. In this review, we summarize the experimental results on the mechanism of neuroprotection induced by standardized extract of Ginkgo biloba leaves (EGb 761) and its constituents. The effects described mostly in animals include those on cerebral blood flow, neurotransmitter systems, cellular redox state and nitric oxide level. Furthermore, we discuss the current status of clinical trials as well as undesired side effects of EGb 761.Received 21 November 2002; received after revision 8 March 2003; accepted 17 March 2003     

Annexin A5: shifting from a diagnostic towards a therapeutic realm

The surge in apoptosis research and the discovery of the phosphatidylserine binding properties of annexin A5 have propelled a tremendous interest in cell death detection technologies. In the past years, annexin A5 has evolved from an efficient assay for detection of apoptotic cells in vitro to an in vivo molecular imaging technology with potential clinical use. A second key discovery, the specific internalization properties of annexin A5, has opened the opportunity to use annexin A5 for therapeutic applications. Annexin A5-mediated internalization creates a novel therapeutic platform for targeted drug delivery and cell entry to treat various diseases, including cancer and cardiovascular disease. Received 29 June 2007; received after revision 19 July 2007; accepted 15 August 2007     

Mcl-1 is a potential therapeutic target in multiple types of cancer

Resistance to apoptosis is a common challenge in human malignancies contributing to both progress of cancer and resistance to conventional therapeutics. Abnormalities in a variety of cell intrinsic and extrinsic molecular mechanisms cooperatively promote tumor formation. Therapeutic approaches that specifically target components of these molecular mechanisms are getting widespread attention. Mcl-1 is a highly expressed pro-survival protein in human malignancies and its cellular expression is tightly regulated via multiple mechanisms. Mcl-1 differs from other members of the Bcl-2 family in having a very short half-life. So inhibition of its expression and/or neutralization of its anti-apoptotic function will rapidly make Mcl-1-dependent cells more susceptible to apoptosis and provide an opportunity to combat several types of cancers. This review summarizes the current knowledge on the regulation of Mcl-1 expression and discusses the alternative approaches targeting Mcl-1 in human cancer cells whose survivals mainly depend on Mcl-1. Received 6 October 2008; received after revision 21 October 2008; accepted 10 November 2008     

Microsatellite instability in gastric cancer: molecular bases,clinical perspectives,and new treatment approaches

Gastric cancer is one of the most aggressive malignancies, with limited treatment options in both locally advanced and metastatic setting, resulting in poor prognosis. Based on genomic characterization, stomach tumour has recently been described as a heterogeneous disease composed by different subtypes, each of them with peculiar molecular aspects and specific clinical behaviour. With an incidence of 22% among all western gastric tumour cases, stomach cancer with microsatellite instability was identified as one of these subgroups. Retrospective studies and limited prospective trials reported differences between gastric cancers with microsatellite stability and those with instability, mainly concerning clinical and pathological features, but also in regard to immunological microenvironment, correlation with prognostic value, and responses to treatment. In particular, gastric cancer with microsatellite instability constitutes a small but relevant subgroup associated with older age, female sex, distal stomach location, and lower number of lymph-node metastases. Emerging data attribute to microsatellite instability status a favourable prognostic meaning, whereas the poor outcomes reported after perioperative chemotherapy administration suggest a detrimental role of cytotoxic drugs in this gastric cancer subgroup. The strong immunogenicity and the widespread expression of immune-checkpoint ligands make microsatellite instability subtype more vulnerable to immunotherapeutic approach, e.g., with anti-PD-L1 and anti-CTLA4 antibodies. Since gastric cancer with microsatellite instability shows specific features and clinical behaviour not overlapping with microsatellite stable disease, microsatellite instability test might be suitable for inclusion in a diagnostic setting for all tumour stages to guarantee the most targeted and effective treatment to every patient.     

Both morphological and molecular characters support speciation of South American siskins by sexual selection

South American siskin radiation was studied by both mitochondrial cytochrome b (mt cyt b) DNA sequencing and homologous phenotypic characters; the latter were coded separately according to sex. Mixed phenetic and molecular (total evidence) dendrograms were constructed and the corresponding analyses suggest that speciation started in the South American siskin group with a north to south separation (Carduelis notata/C. barbata) along the Andean spine. A second split may have taken place around the Peruvian Andean mountains, corresponding to the present distribution pattern of C. olivacea. The most recent speciation events seem to have occurred in three sister species pairs: (i) C. xanthogastra/C. atrata, (ii) C. magellanica/C. yarrellii, (iii) C. cucullata/C. crassirostris. Accumulation of consistent characters in both morphological and molecular data at the basal nodes of the dendrograms indicate that speciation events occurred within a short period of time. Our data also suggest that speciation probably occurred by sexual selection through female mating choice in this radiation. Additionally, studies of variable amino acid residues in the mt cyt b molecule show that the three variable amino acids found are placed in the mitochondrial transmembrane region, which is also part of the hypervariable region in mammals. Each of the three amino acid changes occur in each of the three postulated evolutionary groups. Received 11 September 2001; received after revision 12 October 2001; accepted 15 October 2001     

The structure of human interferon-β: implications for activity

Interferons (IFNs) are potent extracellular protein mediators of host defence and homoeostasis. This article reviews the structure of human IFN-β (HuIFN-β), in particular in relation to its activity. The recently determined crystal structure of HuIFN-β provides a framework for understanding of the mechanism of differentiation of type I IFNs by their common receptor. Insights are generated by comparison with the structures of other type I IFNs and from the interpretation of existing mutagenesis data. The details of the observed carbohydrate structure, together with biochemical data, implicate the glycosylation of HuIFN-β, which is uncommon among type I IFNs, as an important factor in the solubility, stability and, consequently, activity of the protein. Finally, these structural implications are discussed in the context of the clinical use of HuIFN-β. Received 12 June 1998; received after revision 16 July 1998; accepted 16 July 1998     

Two new aminopeptidases from Ochrobactrum anthropi active on D-alanyl-p-nitroanilide

Two new enzymes which hydrolyse D-alanyl-p-nitroanilide have been detected in Ochrobactrum anthropi LMG7991 extracts. The first enzyme, DmpB, was purified to homogeneity and found to be homologous to the Dap protein produced by O. anthropi SCRC C1-38 (ATCC49237). The second enzyme, DmpA, exhibits a similar substrate profile when tested on p-nitroanilide derivatives of glycine and L/D-alanine, but the amounts produced by the Ochrobactrum strain were not sufficient to allow complete purification. Interestingly, the DmpA preparation also exhibited an L-aminopeptidase activity on the tripeptide L-Ala-Gly-Gly but it was not possible to be certain that the same protein was responsible for both p-nitroanilide and peptide hydrolysing activities. The gene encoding the DmpA protein was cloned and sequenced. The deduced protein sequence exhibits varying degrees of similarity with those corresponding to several open reading frames found in the genomes of other prokaryotic organisms, including Mycobacteria. None of these gene products has been isolated or characterised, but a tentative relationship can be proposed with the NylC amidase from Flavobacterium sp. K172. Received 7 December 1998; received after revision 15 March 1999; accepted 22 March 1999     

Ongoing therapeutic trials and outcome measures for Duchenne muscular dystrophy

Muscular dystrophy is a heterogeneous group of genetic disorders characterised by progressive muscle tissue degeneration. No effective treatment has been discovered for these diseases. Preclinical and clinical studies aimed at the development of new therapeutic approaches have been carried out, primarily in subjects affected with dystrophinopathies (Duchenne and Becker muscular dystrophy). In this review, we outline the current therapeutic approaches and past and ongoing clinical trials, highlighting both the advantages and limits of each one. The experimental designs of these trials were based on different rationales, including immunomodulation, readthrough strategies, exon skipping, gene therapy, and cell therapy. We also provide an overview of available outcome measures, focusing on their reliability in estimating meaningful clinical improvement in order to aid in the design of future trials. This perspective is extremely relevant to the field considering the recent development of novel therapeutic approaches that will result in an increasing number of clinical studies over the next few years.