The Novel SSTR3 Agonist ITF2984 Exerts Antimitotic and Proapoptotic Effects in Human Non-Functioning Pituitary Neuroendocrine Tumor (NF-PitNET) Cells

Somatostatin receptor ligands (SRLs) with high affinity for somatostatin receptors 2 and 5 (SSTR2 and SSTR5) are poorly efficacious in NF-PitNETs, expressing high levels of SSTR3. ITF2984 is a pan-SSTR ligand with high affinity for SSTR3, able to induce SSTR3 activation and to exert antitumoral activity in the MENX rat model. The aim of this study was to test ITF2984's antiproliferative and proapoptotic effects in NF-PitNET primary cultured cells derived from surgically removed human tumors and to characterize their SSTR expression profile. We treated cells derived from 23 NF-PitNETs with ITF2984, and a subset of them with octreotide, pasireotide (SRLs with high affinity for SSTR2 or 5, respectively), or cabergoline (DRD2 agonist) and we measured cell proliferation and apoptosis. SSTR3, SSTR2, and SSTR5 expression in tumor tissues was analyzed by qRT-PCR and Western blot. We demonstrated that ITF2984 reduced cell proliferation (-40.8 (17.08)%, p < 0.001 vs. basal, n = 19 NF-PitNETs) and increased cell apoptosis (+41.4 (22.1)%, p < 0.001 vs. basal, n = 17 NF-PitNETs) in all tumors tested, whereas the other drugs were only effective in some tumors. In our model, SSTR3 expression levels did not correlate with ITF2984 antiproliferative nor proapoptotic effects. In conclusion, our data support a possible use of ITF2984 in the pharmacological treatment of NF-PitNET.

Identification of a Novel SSTR3 Full Agonist for the Treatment of Nonfunctioning Pituitary Adenomas

Somatostatin receptor (SSTR) agonists have been extensively used for treating neuroendocrine tumors. Synthetic therapeutic agonists showing selectivity for SSTR2 (Octreotide) or for SSTR2 and SSTR5 (Pasireotide) have been approved for the treatment of patients with acromegaly and Cushing's syndrome, as their pituitary tumors highly express SSTR2 or SSTR2/SSTR5, respectively. Nonfunctioning pituitary adenomas (NFPAs), which express high levels of SSTR3 and show only modest response to currently available SSTR agonists, are often invasive and cannot be completely resected, and therefore easily recur. The aim of the present study was the evaluation of ITF2984, a somatostatin analog and full SSTR3 agonist, as a new potential treatment for NFPAs. ITF2984 shows a 10-fold improved affinity for SSTR3 compared to Octreotide or Pasireotide. Molecular modeling and NMR studies indicated that the higher affinity for SSTR3 correlates with a higher stability of a distorted β-I turn in the cyclic peptide backbone. ITF2984 induces receptor internalization and phosphorylation, and triggers G-protein signaling at pharmacologically relevant concentrations. Furthermore, ITF2984 displays antitumor activity that is dependent on SSTR3 expression levels in the MENX (homozygous mutant) NFPA rat model, which closely recapitulates human disease. Therefore, ITF2984 may represent a novel therapeutic option for patients affected by NFPA.

Health alliance for prudent prescribing and yield of antibiotics in a patient-centred perspective (HAPPY PATIENT): a before-and-after intervention and implementation study protocol

Background

Excessive and inappropriate use of antibiotics is the most important driver of antimicrobial resistance. The aim of the HAPPY PATIENT project is to evaluate the adaptation of European Union (EU) recommendations on the prudent use of antimicrobials in human health by evaluating the impact of a multifaceted intervention targeting different categories of healthcare professionals (HCPs) on common community-acquired infectious diseases, especially respiratory and urinary tract infections.

Methods/design

HAPPY PATIENT was initiated in January 2021 and is planned to end in December 2023. The partners of this project include 15 organizations from 9 countries. Diverse HCPs (doctors, nurses, pharmacists, and pharmacy technicians) will be audited by the Audit Project Odense (APO) method before and after an intervention in four different settings: general practice, out of hours services, nursing homes and community pharmacies in four high antibiotic prescribing countries (France, Poland, Greece, and Spain) and one low prescribing country (Lithuania). About 25 individuals from each professional group will be recruited in each country, who will register at least 25 patients with community-acquired infections during each audit period. Shortly before the second registration participants will undertake a multifaceted intervention and will receive the results from the first registration to allow the identification of possible quality problems. At these meetings participants will receive training courses on enhancement of communication skills, dissemination of clinical guidelines with recommendations for diagnosis and treatment, posters for the waiting rooms, and leaflets for patients. The results of the second registration will be compared with those obtained in the first audit.

Discussion

HAPPY PATIENT is an EU-funded project aimed at contributing to the battle against antibiotic resistance through improvement of the quality of management of common community-acquired infections based on interventions by different types of HCPs. It is hypothesized that the use of multifaceted strategies combining active intervention will be effective in reducing inappropriate prescribing and dispensing of antibiotics.

Study registration

EU Health programmes project database https://webgate.ec.europa.eu/chafea_pdb/health/projects/900024/summary; date of registration: 1 January 2021.

Modeling the interference between shear and longitudinal waves under high intensity focused ultrasound propagation in bone

Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) is a noninvasive thermal technique that enables rapid heating of a specific area in the human body. Its clinical relevance has been proven for the treatments of soft tissue tumors, like uterine fibroids, and for the treatments of solid tumors in bone. In MR-HIFU treatment, MR-thermometry is used to monitor the temperature evolution in soft tissue. However, this technique is currently unavailable for bone tissue. Computer models can play a key role in the accurate prediction and monitoring of temperature. Here, we present a computer ray tracing model that calculates the heat production density in the focal region. This model accounts for both the propagation of shear waves and the interference between longitudinal and shear waves. The model was first compared with a finite element approach which solves the Helmholtz equation in soft tissue and the frequency-domain wave equation in bone. To obtain the temperature evolution in the focal region, the heat equation was solved using the heat production density generated by the raytracer as a heat source. Then, we investigated the role of the interaction between shear and longitudinal waves in terms of dissipated power and temperature output. The results of our model were in agreement with the results obtained by solving the Helmholtz equation and the frequency-domain wave equation, both in soft tissue and bone. Our results suggest that it is imperative to include both shear waves and their interference with longitudinal waves in the model when simulating high intensity focused ultrasound propagation in solids. In fact, when modeling HIFU treatments, omitting the interference between shear and longitudinal waves leads to an over-estimation of the temperature increase in the tissues.

Modelling the temperature evolution of bone under high intensity focused ultrasound

Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has been clinically shown to be effective for palliative pain management in patients suffering from skeletal metastasis. The underlying mechanism is supposed to be periosteal denervation caused by ablative temperatures reached through ultrasound heating of the cortex. The challenge is exact temperature control during sonication as MR-based thermometry approaches for bone tissue are currently not available. Thus, in contrast to the MR-HIFU ablation of soft tissue, a thermometry feedback to the HIFU is lacking, and the treatment of bone metastasis is entirely based on temperature information acquired in the soft tissue adjacent to the bone surface. However, heating of the adjacent tissue depends on the exact sonication protocol and requires extensive modelling to estimate the actual temperature of the cortex. Here we develop a computational model to calculate the spatial temperature evolution in bone and the adjacent tissue during sonication. First, a ray-tracing technique is used to compute the heat production in each spatial point serving as a source term for the second part, where the actual temperature is calculated as a function of space and time by solving the Pennes bio-heat equation. Importantly, our model includes shear waves that arise at the bone interface as well as all geometrical considerations of transducer and bone geometry. The model was compared with a theoretical approach based on the far field approximation and an MR-HIFU experiment using a bone phantom. Furthermore, we investigated the contribution of shear waves to the heat production and resulting temperatures in bone. The temperature evolution predicted by our model was in accordance with the far field approximation and agreed well with the experimental data obtained in phantoms. Our model allows the simulation of the HIFU treatments of bone metastasis in patients and can be extended to a planning tool prior to MR-HIFU treatments.

Specific inhibition of histone deacetylase 8 reduces gene expression and production of proinflammatory cytokines in vitro and in vivo

ITF2357 (generic givinostat) is an orally active, hydroxamic-containing histone deacetylase (HDAC) inhibitor with broad anti-inflammatory properties, which has been used to treat children with systemic juvenile idiopathic arthritis. ITF2357 inhibits both Class I and II HDACs and reduces caspase-1 activity in human peripheral blood mononuclear cells and the secretion of IL-1β and other cytokines at 25-100 nm; at concentrations >200 nm, ITF2357 is toxic in vitro. ITF3056, an analog of ITF2357, inhibits only HDAC8 (IC50 of 285 nm). Here we compared the production of IL-1β, IL-1α, TNFα, and IL-6 by ITF2357 with that of ITF3056 in peripheral blood mononuclear cells stimulated with lipopolysaccharide (LPS), heat-killed Candida albicans, or anti-CD3/anti-CD28 antibodies. ITF3056 reduced LPS-induced cytokines from 100 to 1000 nm; at 1000 nm, the secretion of IL-1β was reduced by 76%, secretion of TNFα was reduced by 88%, and secretion of IL-6 was reduced by 61%. The intracellular levels of IL-1α were 30% lower. There was no evidence of cell toxicity at ITF3056 concentrations of 100-1000 nm. Gene expression of TNFα was markedly reduced (80%), whereas IL-6 gene expression was 40% lower. Although anti-CD3/28 and Candida stimulation of IL-1β and TNFα was modestly reduced, IFNγ production was 75% lower. Mechanistically, ITF3056 reduced the secretion of processed IL-1β independent of inhibition of caspase-1 activity; however, synthesis of the IL-1β precursor was reduced by 40% without significant decrease in IL-1β mRNA levels. In mice, ITF3056 reduced LPS-induced serum TNFα by 85% and reduced IL-1β by 88%. These data suggest that specific inhibition of HDAC8 results in reduced inflammation without cell toxicity.

Modulation of gamma globin genes expression by histone deacetylase inhibitors: an in vitro study

Induction of fetal haemoglobin (HbF) is a promising therapeutic approach for the treatment of β-thalassaemia and sickle cell disease (SCD). Several pharmacological agents, such as hydroxycarbamide (HC) and butyrates, have been shown to induce the γ-globin genes (HBG1, HBG2). However, their therapeutic use is limited due to weak efficacy and an inhibitory effect on erythroid differentiation. Thus, more effective agents are needed. The histone deacetylase (HDAC) inhibitors are potential therapeutic haemoglobin (Hb) inducers able to modulate gene expression through pleiotropic mechanisms. We investigated the effects of a HDAC inhibitor, Givinostat (GVS), on erythropoiesis and haemoglobin synthesis and compared it with sodium butyrate and HC. We used an in vitro erythropoiesis model derived from peripheral CD34⁺ cells of healthy volunteers and SCD donors. GVS effects on erythroid proliferation and differentiation and on Hb synthesis were investigated. We found that GVS at high concentrations delayed erythroid differentiation with no specific effect on HBG1/2 transcription. At a low concentration (1 nmol/l), GVS induced Hb production with no effects on cells proliferation and differentiation. The efficacy of GVS 1 mol/l in Hb induction in vitro was comparable to that of HC and butyrate. Our results support the evaluation of GVS as a new candidate molecule for the treatment of the haemoglobinophathies due to its positive effects on haemoglobin production at low and non-toxic concentrations.

Pharmacokinetics, safety and inducible cytokine responses during a phase 1 trial of the oral histone deacetylase inhibitor ITF2357 (givinostat)

ITF2357 (givinostat) is a histone deacetylase inhibitor with antiinflammatory properties at low nanomolar concentrations. We report here a phase I safety and pharmacokinetics trial in healthy males administered 50, 100, 200, 400 or 600 mg orally. After 50 mg, mean maximal plasma concentrations reached 104 nmol/L 2 h after dosing, with a half-life of 6.9 h. After 100 mg, maximal concentration reached 199 nmol/L at 2.1 h with a half-life of 6.0 h. Repeat doses for 7 consecutive days of 50, 100 or 200 mg resulted in nearly the same kinetics. There were no serious adverse effects (AEs) and no organ toxicities. However, there was a dose-dependent but transient fall in platelets. After 7 daily doses of 50 or 100 mg, the mean decrease in platelets of 17 and 25% was not statistically significant and returned to baseline within 14 d. Blood removed from the subjects after oral dosing was cultured ex vivo with endotoxin, and the release of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-1Ra, interferon (IFN)-γ and IL-10 was determined. Maximal reduction in IL-1β, TNFα, IL-6 and IFNγ was observed 4 h after dosing but returned to baseline at 12 h. There was no significant reduction in IL-1Ra or IL-10. With daily dosing, the fall in cytokine production in blood cultures observed on day 7 was nearly the same as that of the first day. We conclude that dosing of 50 or 100 mg ITF2357 is safe in healthy humans and transiently but repeatedly reduces the production of proinflammatory cytokines without affecting production of antiinflammatory cytokines.

The histone deacetylase inhibitor ITF2357 reduces production of pro-inflammatory cytokines in vitro and systemic inflammation in vivo

We studied inhibition of histone deacetylases (HDACs), which results in the unraveling of chromatin, facilitating increased gene expression. ITF2357, an orally active, synthetic inhibitor of HDACs, was evaluated as an anti-inflammatory agent. In lipopolysaccharide (LPS)-stimulated cultured human peripheral blood mononuclear cells (PBMCs), ITF2357 reduced by 50% the release of tumor necrosis factor-alpha (TNFalpha) at 10 to 22 nM, the release of intracellular interleukin (IL)-1alpha at 12 nM, the secretion of IL-1beta at 12.5 to 25 nM, and the production of interferon-gamma (IFNgamma) at 25 nM. There was no reduction in IL-8 in these same cultures. Using the combination of IL-12 plus IL-18, IFNgamma and IL-6 production was reduced by 50% at 12.5 to 25 nM, independent of decreased IL-1 or TNFalpha. There was no evidence of cell death in LPS-stimulated PBMCs at 100 nM ITF2357, using assays for DNA degradation, annexin V, and caspase-3/7. By Northern blotting of PBMCs, there was a 50% to 90% reduction in LPS-induced steady-state levels of TNFalpha and IFNgamma mRNA but no effect on IL-1beta or IL-8 levels. Real-time PCR confirmed the reduction in TNFalpha RNA by ITF2357. Oral administration of 1.0 to 10 mg/kg ITF2357 to mice reduced LPS-induced serum TNFalpha and IFNgamma by more than 50%. Anti-CD3-induced cytokines were not suppressed by ITF2357 in PBMCs either in vitro or in the circulation in mice. In concanavalin-A-induced hepatitis, 1 or 5 mg/kg of oral ITF2357 significantly reduced liver damage. Thus, low, nonapoptotic concentrations of the HDAC inhibitor ITF2357 reduce pro-inflammatory cytokine production in primary cells in vitro and exhibit anti-inflammatory effects in vivo.

ITF1697, a stable Lys-Pro-containing peptide, inhibits weibel-palade body exocytosis induced by ischemia/reperfusion and pressure elevation

A number of Lys-Pro-containing short peptides have been described as possessing a variety of biological activities in vitro. Because of limited metabolic stability, however, their efficacy in vivo is uncertain. To exploit the pharmacological potential of Lys-Pro-containing short peptides, we synthesized a series of chemically modified forms of these peptides. One of them, ITF1697 (Gly-(Nalpha-Et)Lys-Pro-Arg) was stable in vivo and particularly efficacious in experimental models of disseminated endotoxemia and of cardiovascular disorders. Using intravital fluorescence microscopy, we studied the peptide cellular and molecular basis of protection in the Syrian hamster cheek pouch microcirculation subjected to ischemia/reperfusion (I/R) and in pressure elevation-induced proinflammatory responses in isolated Sprague-Dawley rat lungs. Continuous intravenous infusion of ITF1697 at 0.1 to 100 mug/kg/min nearly completely protected the cheek pouch microcirculation from I/R injury as measured by decreased vascular permeability and increased capillary perfusion. Adhesion of leukocytes and platelets to blood vessels was strongly inhibited by the peptide. ITF1697 exerted its activity at the early stages of endothelial activation and inhibited P-selectin and von Willebrand factor secretion. Further mechanistic studies in the rat lung preparation revealed that the peptide inhibited the intracellular Ca(2+)-dependent fusion of Weibel-Palade bodies with the plasma membrane. The ability of ITF1697 to inhibit the early functions of activated endothelial cells, such as the exocytosis of Weibel-Palade bodies, represents a novel and promising pharmacological tool in model of pathologies of a variety of microvascular disorders.

Mycobacterium tuberculosis chaperonin 10 is secreted in the macrophage phagosome: is secretion due to dissociation and adoption of a partially helical structure at the membrane?

To confirm that Mycobacterium tuberculosis chaperonin 10 (Cpn10) is secreted outside the live bacillus, infected macrophages were examined by electron microscopy. This revealed that the mycobacterial protein accumulates both in the wall of the bacterium and in the matrix of the phagosomes in which ingested mycobacteria survive within infected macrophages. To understand the structural implications underlying this secretion, a structural study of M. tuberculosis Cpn10 was performed under conditions that are generally believed to mimic the membrane environment. It was found that in buffer-organic solvent mixtures, the mycobacterial protein forms two main species, namely, a partially helical monomer that prevails in dilute solutions at room temperature and a dimer that folds into a beta-sheet-dominated structure and prevails in either concentrated protein solutions at room temperature or in dilute solutions at low temperature. A partially helical monomer was also found and was completely associated with negatively charged detergents in a micelle-bound state. Remarkably, zwitterionic lipids had no effect on the protein structure. By using N- and C-truncated forms of the protein, the C- and N-terminal sequences were identified as possessing an amphiphilic helical character and as selectively associating with acidic detergent micelles. When the study was extended to other chaperonins, it was found that human Cpn10 is also monomeric and partially helical in dilute organic solvent-buffer mixtures. In contrast, Escherichia coli Cpn10 is mostly dimeric and predominately beta-sheet in both dilute and concentrated solutions. Interestingly, human Cpn10 also crosses biological membranes, whereas the E. coli homologue is strictly cytosolic. These results suggest that dissociation to partially helical monomers and interaction with acidic lipids may be two important steps in the mechanism of secretion of M. tuberculosis Cpn10 to the external environment.

Preventive administration of Mycobacterium tuberculosis 10-kDa heat shock protein (hsp10) suppresses adjuvant arthritis in Lewis rats

Adjuvant arthritis (AA) can be induced in Lewis rats by immunization with Mycobacterium tuberculosis (Mt) in oil. We have investigated the modulation of AA by mycobacterial 10-kDa heat shock protein (hsp10), administered according to several protocols known to induce immune tolerance and immune deviation. Subcutaneous immunization with hsp10 in aqueous solution did not induce a cellular immune response, evaluated as delayed-type hypersensitivity (DTH) reaction, although anti-hsp10 antibodies, mainly of the IgG2a isotype, were detected in serum of treated animals. When rats were pretreated with hsp10 in aqueous solution before AA induction, no effects were seen on arthritis-induced joint swelling, although osteolysis and lymphocyte infiltration were slightly decreased. When other routes of administration were attempted, the strongest suppression was seen in the group of animals which received four intranasal (i.n.) administrations of protein and a subsequent challenge of hsp10 in incomplete Freund's adjuvant (IFA). We also found that the extent of disease suppression among the different groups of animals correlated with serum anti-hsp10 antibody levels. These antibodies mostly belonged to the IgG2a subtype, suggesting that immune deviation may play a role in the mechanism of disease suppression by hsp10.

Chaperonin 10 of Mycobacterium tuberculosis induces a protective immune response to foot-and-mouth disease virus

Chaperonin 10 of M. tuberculosis conferred partial or total protection against generalized foot-and-mouth disease (FMD) in guinea-pigs challenged with O1 Lausanne FMD virus. Chaperonin 10-immunized animals mounted an antibody response to the protein, one epitope of which was found in the C-terminal half. A similar recognition pattern was observed in FMD-convalescent guinea-pigs, swine and cattle. Anti-chaperonin 10 sera showed antiviral activity against FMDV-infected BHK-21 cells. There was strong evidence that early after infection these cells actively secrete their histones and that antisera to the chaperonin recognize them. The same antisera reacted with purified histones in immunoblotting. Most important, exogenously added histones abrogated the anti-viral activity of the antiserum and an anti-histone monoclonal antibody had strong antiviral activity against FMDV-infected BHK-21 cells. These results are consistent with previous reports on displacement of histones from the nuclear compartment and immune recognition of self-histones after viral infections. On the whole, they indicate that M. tuberculosis chaperonin 10 enables the immune system to react against early abnormalities of virus-infected cells; this is accomplished by antibody cross-reacting with histones released during virus infection.

Mycobacterial Cpn10 promotes recognition of the mammalian homologue by a mycobacterium-specific antiserum

Self-tolerance, a key feature of the immune system, is still a matter of intense debate. We give here evidence for a peculiar behavior of an antiserum against Mycobacterium tuberculosis chaperonin 10 (m-Cpn10), which could have implications for the mechanism of self-recognition by antibodies against non-self. We show that this antiserum can interact in terms of both inhibition of biological activity and physical association (immunoprecipitation), with the mammalian homologue of m-Cpn10, but only if the bacterial protein is present. Several lines of evidence led us to exclude that the two proteins physically associate to form heterocomplexes: (1) the behavior of the antiserum was not shared by a monoclonal antibody against m-Cpn10; (2) a matrix selective for human Cpn10 (h-Cpn10) did not co-purify m-Cpn10; (3) the distribution pattern in non-denaturing isoelectric focusing of labeled m-Cpn10 was not altered by the presence of the unlabeled h-Cpn10. We conclude therefore that the antiserum against M. tuberculosis Cpn10 also recognizes mammalian Cpn10, with an affinity/avidity regulated by the mycobacterial protein, or by the promotion of hetero-oligomerization. This emergence of self-recognition in the presence of M. tuberculosis Cpn10 could imply a breaking of self-tolerance in situations of infection or vaccination.

Diaminic carbonates, a new class of anti-inflammatory compounds: their biological characterization and mode of action

Taking advantage of a standard assay on mouse LM cells (murine fibroblast-like cells), we found that several diaminic carbonates, a new class of organic compounds synthesized in our laboratories, were able to inhibit human tumor necrosis factor alpha (huTNFalpha)-induced cytotoxicity in a dose-dependent manner. Structure-function relationship studies indicated precise structural requirements for compounds being active as huTNFalpha inhibitors. ITF1779, one of the most active compounds in inhibiting huTNFalpha-induced cytotoxicity, was selected for further studies. In vitro experiments showed that ITF1779 inhibited not only huTNFalpha-induced cytotoxicity on LM cells but also another response of the same cells, interleukin-1-induced interleukin-6 production. Receptor-binding studies performed under nonequilibrium conditions and morphologic evidence of vacuole formation in cells treated with high concentrations of ITF1779 showed that the effects were strikingly similar to those of chloroquine, a lysosomotropic agent. Consistent with a mechanism of action of diaminic carbonates closely matching that of chloroquine are some structural similarities between the two classes of compounds, in particular their both being diprotic weak bases. Moreover, ITF1779 was shown to be active in vivo because it afforded protection against lipopolysaccharide-induced shock in mice, a systemic inflammatory response crucially dependent on tumor necrosis factoralpha production.

Heterologous expression, purification, activity and conformational studies of different forms of dianthin 30

Dianthin 30, a ribosome inactivating protein (RIP) from Dianthus caryophyllus, has been expressed in Escherichia coli. Heterologous expression of a deletion mutant dianthin 30 delta 255-270 resulted in the production of a protein identical to carnation mature dianthin 30, including the absence at the carboxy-terminal of a putative 16 amino acid long pro-signal peptide. The production of a form of dianthin 30, which includes the pro-signal, is described as well. Both dianthin 30 delta 255-270 and dianthin 30 expressed in E. coli are mainly localized (90%) in the soluble fraction. Dianthin 30 delta 255-270 and dianthin 30 have been purified to homogeneity and were shown to inhibit protein synthesis in vitro with an IC50 of 8 and of 11 ng/ml, respectively. Secondary structure analysis, carried out by circular dichroism spectroscopy, indicated that the naturally occurring and the recombinant forms of dianthin 30 and dianthin 30 delta 255-270 possess the same secondary structure composition, accounting for an alpha + beta type architecture. RIPs as immunotoxins in clinical trial and as mitotoxins in experimental models have been extremely efficacious. In addition, growing evidence indicates their effective use as antiviral agents, including in HIV-1 infection. These data indicate the ability to produce either chemically linked or recombinant fusion proteins with dianthin 30 and cell-binding ligands for production of new reagents for clinical and experimental use.

Evidence for GroES acting as a transcriptional regulator

Cochaperonins (cpn10) assist chaperonins (cpn60) in promoting folding and assembly of other proteins. Upon expression of Mycobacterium tuberculosis cpn10 in Escherichia coli we have purified a polypeptide which, through amino acid sequencing, was identified as the endogenous E. coli 10K-S protein. Subsequent studies showed that its expression was specifically upregulated upon cloning of different members of the cpn10 family, including GroES, the E. coli cpn10. Pulse-chase experiments demonstrated that 10K-S is but one of several proteins whose expression is modulated upon cloning of cpn10. Up-regulation of 10K-S was also observed after exposure of normal cells, but not of groES- mutants, to elevated temperatures (42 degrees C). This allowed us to define 10K-S as a heat-shock protein (hsp) whose expression is dependent on the production of another hsp, GroES. Northern blot experiments showed that enhanced expression of 10K-S was consequent to increased accumulation of transcripts and that groES- mutants were devoid even of baseline levels of transcripts both at 37 degrees C and after temperature upshift. These results show that GroES, in addition to its established role in assisting protein folding may act as a transcriptional regulator and is likely to play an important role in modulating gene expression particularly in those conditions, like the stress response, in which its production is greatly enhanced.

Different cytotoxic activity and intracellular fate of an anti-CD5-momordin immunotoxin in normal compared to tumour cells

We investigated the different sensitivity of peripheral blood mononuclear cells (PBMC) and human T cell leukaemias (Jurkat and CEM) to an anti-CD5-momordin immunotoxin. In a short-term assay, the immunotoxin displayed different cytotoxic activity on normal and tumour cells: for leukaemic cell lines an incubation time of 72 h was necessary for the immunotoxin to reach the IC50 of 41-53 pM, compared to the 1 h sufficient for 6 pM immunotoxin to inhibit 50% of PBMC protein synthesis. In a long-term clonogenic assay (15 days), the immunotoxin demonstrated a comparable efficacy of clonogenic cell killing for both cell types. We investigated the immunotoxin internalization pathway by a flow-cytometric method and our data seem to indicate that the molecules meet a different intracellular fate in the two cell populations. It may be assumed that the low cytotoxic activity of immunotoxins on tumour cells, detected in the short-term assay, is due to inefficient delivery to their cytoplasmatic target, while a longer exposure of the cells to the immunotoxin promotes adequate intracellular distribution.

Expression in Escherichia coli, purification and functional activity of recombinant human chaperonin 10

We have recently reported the cloning of a cDNA coding for a stress inducible human chaperonin 10. The protein was shown to possess 100% identity with the bovine homologue and a single amino acid replacement (glycine to serine at position 52) compared to rat chaperonin 10. Here we report the heterologous expression of human chaperonin 10 in Escherichia coli, its purification and its functional characterization. The recombinant protein was purified to homogeneity as judged by different analytical techniques, and mass spectrometry analysis showed a MW of 10,801 Da in agreement with the predicted sequence. This molecular weight accounts for a protein which is not modified post-translationally. In fact, natural rat chaperonin 10 has been shown to be acetylated at the N-terminus, a feature suggested to be important for targeting and functional activity. Here we show that recombinant human chaperonin 10 is fully active in assisting the chaperonin 60 GroEL in the refolding of denatured yeast enolase, thereby showing that, at least in the present system, post-translational acetylation is not necessary for its activity.

Anti-CD30 immunotoxins with native and recombinant dianthin 30

Immunotoxins were prepared with a Ber-H2 (anti-CD30) monoclonal antibody and native or recombinant dianthin 30, a ribosome-inactivating protein from Dianthus caryophyllus (carnation). Both immunotoxins selectively inhibited protein synthesis by CD30+ cell lines D430B (lymphoblastoid, infected with Epstein-Barr virus), L428 and L540 (both from Hodgkin's lymphoma). IC50 values (concentrations, as dianthin, causing 50% inhibition) ranged from 324 pM to 479 pM (immunotoxin with native dianthin 30) or from 45 pM to 182 pM (immunotoxin with recombinant dianthin 30). The effect of either immunotoxin on protein synthesis by the CD30+ cell line K562 (from a chronic myeloid leukaemia) was not different from that of free dianthin (IC50 higher than nM).

Cochaperonins are histone-binding proteins

Cochaperonins (cpn10) assist chaperonins (cpn60) in mediating folding of polypeptide substrates in an ATP-dependent reaction. Moreover, they have been shown to be secretory products of living cells and to perform discrete biological activities without the need to interact with cpn60. Here, we have investigated the possible existence of cellular cpn10 binding sites that could mediate such activities. For this purpose, we performed binding studies with iodinated cpn10 on whole cells and on electrophoretically separated eukaryotic cell lysates. The former studies yielded negative results, whereas in the latter binding to several proteins was detected. These proteins were identified as being histones. Binding was observed to all core histones (H2A, H2B, H3 and H4) and, although weaker, to the linker histone H1 as well. These results show that cpn10 are histone-binding proteins.

Identification and cloning of human chaperonin 10 homologue

We have identified a heat-shock-inducible 10 kDa protein in the human hepatoma cell line HepG2. The total RNA extracted from the heat-shocked cells was amplified by reverse transcription PCR (polymerase chain reaction) using 21 5' and 18 3' oligonucleotides of rat cpn10 (chaperonin10) cDNA as primers. Sequencing of the above PCR fragment showed a very high homology between human, bovine and rat cpn10 cDNA. The predicted amino acid sequence revealed a 100% identity with the bovine homologue.

Production and characterization of monoclonal antibodies against the ribosome inactivating proteins dianthin32 and momochin

Female BALB/c mice were immunized with either dianthin32 or momochin, type 1 ribosome-inactivating proteins (RIPs) derived from Dianthus charyophyllus and Momordica cochinchinensis, respectively. Five anti-dianthin32 and 6 anti-momochin secreting hybridomas were obtained by somatic fusion of lymphocytes with myeloma cell line NS0. The monoclonal antibodies (MAbs) produced were highly specific, as demonstrated by cross-reactivity assays performed with taxonomically related and unrelated type 1 RIPs, and recognized different epitopes of the antigen. The affinity constant of anti-RIPs MAbs ranged between 10(8) M-1 and 10(10) M-1.

Delivery of saporin to human B-cell lymphoma using bispecific antibody: targeting via CD22 but not CD19, CD37, or immunoglobulin results in efficient killing

A panel of bispecific F(ab')2 antibodies (BsAb) have been constructed for delivering the ribosome-inactivating protein saporin to human B cell lymphoma. Each derivative was prepared with specificity for saporin and CD19, CD22, CD37, or immunoglobulin. In vitro studies measuring inhibition of [3H]leucine uptake by cultured Daudi and Raji cells demonstrated that, despite all BsAb capturing saporin on the cell surface, BsAb targeting through CD22 were far more cytotoxic than those functioning via CD19, CD37, or surface immunoglobulin. This exceptional activity of the CD22-specific BsAb appears to derive from its ability to deliver and accumulate saporin inside the target cells. Further studies showed that four CD22-specific BsAb all performed with equal potency and were able to increase saporin toxicity (50% inhibitory concentration) up to 1000-fold, from 2 x 10(-7) M to 2 x 10(-10) M. Pairs of anti-CD22 BsAb which recognized different nonblocking epitopes on the saporin molecule were able to bind saporin more avidly to the target cell and, as a consequence, increased cytotoxicity by at least an additional 10-fold, resulting in 50% inhibitory concentration for protein synthesis of 2 x 10(-11) M. These results suggest that selected combinations of BsAb which bind cooperatively to a toxin and the cell surface may provide an efficient way of delivering toxins to unwanted cells in patients.

Expression and activity of pre-dianthin 30 and dianthin 30

Dianthin 30 is a ribosome inactivating protein (RIP 1) found in different tissues of the carnation (Dianthus caryophyllus). Recently we have isolated and sequenced a cDNA clone from a lambda gt11 expression library [Legname et al. (1991) Biochim. Biophys. Acta 1090, 119-122]. Here we describe specific PCR amplifications of either the full length pre-dianthin 30 or dianthin 30, the mature polypeptide lacking the 23 amino acid signal peptide. In vitro expression of both proteins in reticulocyte lysate generated products of the expected molecular weight. Moreover, the activity of both proteins has been evaluated confirming the characteristics of the natural product. A first attempt to produce recombinant dianthin 30 in Escherichia coli is described.

In vitro and in vivo properties of an anti-CD5-momordin immunotoxin on normal and neoplastic T lymphocytes

An anti-CD5 monoclonal antibody (mAb) was linked to the plant toxin momordin, a type-1 ribosome-inactivating protein purified from Momordica charantia. The in vitro cytotoxicity of the immunotoxin was evaluated as the inhibition of protein and/or DNA synthesis on isolated peripheral blood mononuclear cells (PBMC) and on human T cell leukemia Jurkat. The potency of the immunotoxin on PBMC was very high (IC50 = 1 - 10 pM) and was not affected by blood components. The conjugate was also very efficient in the inhibition of the proliferative response in a mixed lymphocyte reaction (IC50 = 10 pM). Moreover, the in vitro performance of the immunotoxin compared favorably with those reported for other anti-CD5-based immunoconjugates containing ricin A chain. The in vivo activity of the immunotoxin was assessed in the model of nu/nu mice bearing Jurkat leukemia. A significant inhibition of the tumour development (80%, P < 0.01) in the animals treated with immunotoxin was observed. Taken together, the in vitro and in vivo results suggest that the anti-CD5-momordin conjugate may be useful for graft-versus-host disease therapy and potentially in the treatment of CD5-positive leukemias and lymphomas.

Nucleotide sequence of cDNA coding for dianthin 30, a ribosome inactivating protein from Dianthus caryophyllus

Rabbit antibodies raised against dianthin 30, a ribosome inactivating protein from carnation (Dianthus caryophyllus) leaves, were used to identify a full length dianthin precursor cDNA clone from a lambda gt11 expression library. N-terminal amino acid sequencing of purified dianthin 30 and dianthin 32 confirmed that the clone encoded dianthin 30. The cDNA was 1153 basepairs in length and encoded a precursor protein of 293 amino acid residues. The first 23 N-terminal amino acids of the precursor represented the signal sequence. The protein contained a carboxy-terminal region which, by analogy with barley lectin, may contain a vacuolar targeting signal.

Immunocytochemical characterization of mouse monoclonal ACTH antibodies with a note on staining conditions and control procedures

Mouse monoclonal antibodies (MAbs) have been produced against porcine ACTH and tested for their immunocytochemical utility. Ten out of 12 MAbs reacted with formaldehyde-fixed human ACTH[1-39] and fragments thereof. Cytochemical fragment testing revealed that 6 of the 10 MAbs recognized epitopes in the vicinity of the region where porcine ACTH differs from mouse ACTH (amino acids 26, 29 and 31). Both tissue and cytochemical model data indicate that many of the MAbs detected porcine ACTH with somewhat higher potency than human and rat ACTH (rat ACTH[1-39] is identical to mouse ACTH[1-39]). MAbs Nos. 5, 8 and 12, in particular, revealed a highly satisfactory signal to noise ratio also in formalin-fixed, paraffin-embedded specimens. Most of the MAbs were potent in detecting both the high concentrations of ACTH congeners in corticotrophs and melanotrophs and the lower concentrations of such peptides in human antropyloric gastrin cells. Blocking of tissue endogenous peroxidase activity reduced reactivity towards the MAbs. This could be circumvented by use of biotinylated primary antibodies combined with avidin/streptavidin-alkaline phosphatase detection. Availability of MAbs and of the corresponding synthetic antigen also made some quantitative comparisons and analyses of appropriate control procedures possible.

Transcriptional control of glucoamylase synthesis in vegetatively growing and sporulating Saccharomyces species

Three unlinked, homologous genes, STA1, STA2, and STA3, encode the extracellular glycosylated glucoamylase isozymes I, II, and III, respectively, in Saccharomyces species. S. cerevisiae, which is sta0 (absence of functional STA genes in haploids), does carry a glucoamylase gene, delta sta, expressed only during sporulation (W. J. Colonna and P. T. Magee, J. Bacteriol. 134:844-853, 1978; I. Yamashita and S. Fukui, Mol. Cell. Biol. 5:3069-3073, 1985). In this study we examined some of the physiological and genetic factors that affect glucoamylase expression. It was found that STA2 strains grown in synthetic medium produce glucoamylase only in the presence of either Maltrin M365 (a mixture of maltooligosaccharides) or starch. Maximal levels of glucoamylase activity were found in cells grown in rich medium supplemented with glycerol plus ethanol, starch, or Maltrin. When various sugars served as carbon sources they all supported glucoamylase synthesis, although at reduced levels. In any given growth medium glucoamylase isozyme II synthesis was modulated by functionality of the mitochondria. Synthesis of glucoamylase is continuous throughout the growth phases, with maximal secretion taking place in the early stationary phase. In the various regimens, the differences in enzyme accumulation are accounted for by differences in the levels of glucoamylase mRNA. Both glucoamylase mRNA and enzyme activity were drastically and coordinately inhibited in MATa/MAT alpha diploids and by the presence of the regulatory gene STA10. Both effects were partially overcome when the STA2 gene was present on a multicopy plasmid. The STA2 mRNA and glucoamylase were coinduced in sporulating STA2/STA2 diploids. A smaller, coinduced RNA species was also detected by Northern blotting with a STA2 probe. The same mRNA species was detected in sporulating sta0 diploids and is likely to encode the sporulation-specific glucoamylase.

Biochemical and immunological characterization of the STA2-encoded extracellular glucoamylase from saccharomyces diastaticus

In Saccharomyces diastaticus each one of three unlinked genes (STA1, STA2, STA3) encodes a glucoamylase (alpha-1,4 glucanglucohydrolase, EC 3.2.1.3) that allows yeast to grow on starch. The enzyme encoded by the STA2 gene (glucoamylase II) has been purified from culture medium to near homogeneity by ethanol precipitation, Trisacryl M DEAE chromatography, and HPLC gel filtration. Glucoamylase II consists of two identical subunits whose average size is 300 kDa. Under denaturing conditions, the native dimeric enzyme readily dissociates to a monomer. Enzymatic deglycosylation of denatured enzyme gives rise to intermediate, partially glycosylated forms and to a 56-kDa completely deglycosylated protein. Glucoamylase releases glucose units by cleaving alpha-1,4 bonds from the nonreducing end of different oligosaccharides, but has only a barely detectable alpha-1,6 hydrolyzing activity. The pH optimum for the purified enzyme was found to be 5.1. The enzyme has a greater affinity for maltohexaose (Km = 0.98 mM, V/Km = 2.39) than for maltotriose (Km = 2.38, V/Km = 0.68) or maltose (Km = 3.20, V/Km = 0.39). Both polyclonal and monoclonal antibodies have been raised against glucoamylase II. The polyclonal antibodies specifically inhibit yeast glucoamylase II activity in a dose-dependent manner, but are found to immunoblot other yeast glycoproteins as well. This oligosaccharide-specific reaction can be competed out by adding excess mannan without affecting glucoamylase reactivity. The cross-reactivity of the polyclonal antibodies with other amylolytic enzymes correlates well with evolutionary distance. Evidence is presented that monoclonal antibodies specific for either carbohydrate or protein epitopes have been obtained.

Molecular cloning and characterization of the STA2 glucoamylase gene of Saccharomyces diastaticus

The Saccharomyces diastaticus structural gene STA2, encoding an exracellular glucoamylase (1,4-alpha-D-glucan glycohydrolase, EC 3.2.1.3.), has been cloned by complementation of a stao strain. A genomic library was initially constructed from a STA2 yeast strain in the yeast Escherichia coli shuttle cosmid vector pYCl. The Sta+ complementing function was further delimited to an 8.3 kb BglII fragment whose restriction map was found to be similar to related genomic regions of STA1 and STA3. Fusions of several DNA fragments derived from the 8.3 kb BglII fragment with a truncated E. coli beta-galactosidase gene resulted in two overlapping fragments that could direct the production of large fusion proteins in E. coli. These fusion proteins were immunoprecipitable by anti-glucoamylase II antibodies, confirming that the Sta+ complementing fusion was due to the expression of a gene that coded for a yeast glucoamylase. Measurements of the STA1, STA2 and STA3 RNA transcripts by RNA-DNA hybridization using an internal fragment of the cloned STA2 gene as the probe indicated that a common transcript of 2.5 kb is produced by each of the STA genes. Integrative disruption of the STA2 gene through homologous recombination was achieved by transforming a STA2 yeast strain to Sta- using an in vitro constructed donor DNA fragment that has the URA3 gene inserted within the coding region of the cloned glucoamylase gene. This was confirmed by tetrad analysis of crosses between strains carrying a disrupted STA2 and a functional STA2. Southern blot analysis using BamHI digested genomic DNA from 15 tetrads demonstrated consistent co-segregation and Mendelian inheritance of the Sta- phenotype with STA2::URA3. These data further confirm that the cloned DNA that showed Sta+ complementing activity carries a functional STA2 gene that encodes the yeast extracellular glucoamylase II.

Permanent decrease in activity of ornithine decarboxylase antizyme in rat liver during chemical hepatocarcinogenesis

This study was undertaken to determine whether or not there is failure of cellular control of L-ornithine decarboxylase activity by its antizyme, the only known natural intracellular inhibitor protein for L-ornithine decarboxylase activity, in rat liver during hepatocarcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene. The formation of hepatic ornithine decarboxylase antizyme was elicited by i.p. injections of putrescine into rats fed a basal diet and rats fed the carcinogenic diet. The activities of both hepatic ornithine decarboxylase and hepatic ornithine decarboxylase antizyme were measured every month for five months, i.e., until hepatoma was fully developed. During azo-dye hepatocarcinogenesis and in fully developed hepatoma the activity of hepatic ornithine decarboxylase antizyme was always significantly lower than in normal resting liver, with minima at the second and the third months. The hepatoma does not synthesize ornithine decarboxylase antizyme more slowly than normal liver, since the difference could be neither abolished nor lessened by lengthening the time available for antizyme formation. Our results strongly suggest that the high intracellular putrescine levels in the livers of rats during 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis do not exert their normal control on hepatic ornithine decarboxylase activity because of a relative inability of these preneoplastic or neoplastic cells to make the ornithine decarboxylase antizyme.

Restoration of normal ornithine decarboxylase antizyme activity in rat liver after acute carcinogen treatment

This study was undertaken to see whether or not the decrease in ornithine decarboxylase antizyme activity caused in rat liver by a hepatocarcinogen could be reversed. Thioacetamide was administered only once, in a single i.p. injection and at a non-carcinogenic, non-necrogenic dose. The activities of both hepatic ornithine decarboxylase and hepatic ornithine decarboxylase antizyme were measured at intervals of hours after the injection of thioacetamide. The hepatic ornithine decarboxylase antizyme in thioacetamide-treated rats was minimal at 40 and 80 h after carcinogen administration. The reversal process requires a very long time, namely 450 h for normal levels of hepatic ornithine decarboxylase antizyme activity to be restored in treated rats. This time is much longer than that required to restore normal ornithine decarboxylase activity in liver of thioacetamide-treated rats. The results of this study, combined with those of the preceding paper, demonstrate that hepatocarcinogens cause a relative inability of rat liver cells to make the ornithine decarboxylase antizyme and that the irreversibility of this defect in cellular control of ornithine decarboxylase activity may be a constant feature in the neoplastic transformation of the rat liver.

Degrees of malignancy in human primary central nervous system tumors: ornithine decarboxylase levels as better indicators than adenosylmethionine decarboxylase levels

The levels of activity to ornithine decarboxylase (ODC) and adenosylmethionine decarboxylase (AMD) were measured in various types of primary human tumors of the central nervous system (CNS) and whenever possible were related to the malignancy of the tumor graded according to histopathologic criteria. In astrocytomas ODC levels increased linearly and progressively from infratentorial pilocytic astrocytoma (grade I) to glioblastoma multiforme (grade IV) and corrected well with the degree of histologic malignancy of the tumor. AMD activity levels, however, correlated with tumor malignancy only up to grade III astrocytoma. Medulloblastomas exhibited an unusual dichotomy with regard to the levels of polyamine biosynthetic decarboxylases (PBD): Medulloblastomas had the highest ODC activities of all the CNS tumors tested but had low AMD activities. In tumors of neuroepithelial tissue ODC level increases and, when present, AMD level increases were not due to proliferation of new blood vessels, because CNS hemangioblastomas had very low levels of both PBD activities. No significant differences in either of the PBD levels were observed among the several variants of meningiomas tested, the meningotheliomatous, the transitional, and the fibrous meningiomas. However, atypical forms of meningioma, i.e., those with mitotic figures, whatever the histologic variants, had higher levels of ODC, but not of AMD, than the typical forms, i.e., those without mitotic figures.

Changes in th circadian rhythm of ornithine decarboxylase in rat liver during chemical hepatocarcinogenesis

The chronobiology of ornithine decarboxylase (ODC) activity in livers was investigated in noninbred Sprague-Dawley rats fed for 5 months with a basal diet or diets with 3-methyl-4'-(dimethylamino)azobenzene (3-Me-DAB) that were oncogenic or caused bile duct hyperplasia (1-naphthylisothiocyanate) (NIT). After a transient disappearance of the ODC circadian rhythm during month 1 on the oncogenic diet, this rhythm in the livers of the rats was reestablished at 60 and 90 days and then disappeared for the next 2 months. When present, the ODC rhythm in 3-Me-DAB-treated rats had the same daily temporal pattern as that of the controls. In the livers of rats treated with NIT, the ODC circadian rhythm was never detectable, even after only 1 month of feeding. Generally, the 3-Me-DAB feeding induced higher levels of ODC activity than did the NIT feeding. The alternation of the appearance and the disappearance of ODC circadian rhythm might reflect changes in the cell population during neoplastic transformation. Te chronobiologic differences in ODC rhythm between the group fed 3-Me-DAB and the group fed NIT could be related to the different types of proliferating cells involved in the hepatic responses to the two drugs.

Levels of activity of the polyamine biosynthetic decarboxylases as indicators of degree of malignancy of human cutaneous epitheliomas

The activities of ornithine decarboxylase and of S-adenosyl-L-methionine decarboxylase in human normal epidermis, in basal cell epitheliomas, and in squamous cell carcinomas of human skin have been compared. All 3 types of tissues have characteristic levels of each of these enzymes. The normal epidermis had the lowest levels of both ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase activities. The levels of the polyamine biosynthetic decarboxylases in basal cell epitheliomas were significantly higher than those of normal epidermis, but at the same time significantly lower than those present in squamous cell carcinomas. These results support the conclusion that in epithelial malignant tumors of human skin the extent of the increase in the activities of polyamine biosynthetic decarboxylases is well correlated with the neoplasm's growth rate, which is faster in the squamous cell carcinomas than in the basal cell epitheliomas.