Induction of resistance or enhancement to a transplantable murine plasmacytoma by transfer of non-immune leucocytes.

Newborn mice have a lower spontaneous resistance to the growth of a syngeneic plasmacytoma (MOPC-460) as compared to adult mice. The transfer of different leucocyte populations from non-immunized adult donors to newborn mice influence in a dual way the resistance to MOPC-460 growth, depending on the number of cells transferred. The transfer of a low number of neutrophils, thymus or spleen cells enhances the MOPC-460 takes. Higher numbers of neutrophils, thymus or bone marrow cells induce an effective protenction. By contrast, macrophages over a dose of 1 X 10(4) constantly produce a reduction of tumour growth

Hepatocyte growth factor/scatter factor stimulates the Ras-guanine nucleotide exchanger

Hepatocyte growth factor/scatter factor (HGF/SF) induces mitogenesis and cell dissociation upon binding to the protein-tyrosine kinase receptor encoded by the MET proto-oncogene (p190MET). The signal transduction pathways downstream from the receptor activation are largely unknown. We show that HGF/SF activates Ras protein. HGF/SF stimulation of metabolically labeled A549 cells raised the amount of Ras-bound radiolabeled guanine nucleotides by over 5-fold. Furthermore, following HGF/SF stimulation of these cells, 50% of Ras was in the GTP-bound active state. The uptake by Ras of radiolabeled GTP was also increased by 5-fold following HGF/SF stimulation in digitonin-permeabilized A549 cells. Moreover, HGF/SF treatment of A549 cells leads to stimulation of the cytosolic Ras-guanine nucleotide exchange activity, measured as accelerated release of [3H]GDP from purified recombinant Ras protein in vitro, in a dose- and time-dependent manner. Likewise, treatment with the protein-tyrosine kinase inhibitor 3-(1',4'-dihydroxytetralyl)methylene-2-oxindole of GTL-16 cells (featuring a p190MET receptor constitutively active) significantly decreased the cytosolic Ras-guanine nucleotide exchange activity. These data demonstrate that HGF/SF activates Ras protein by shifting the equilibrium toward the GTP-bound state and increases the uptake of guanine nucleotides by Ras, through mechanism(s) including the activation of a Ras-guanine nucleotide exchanger

Targeting the MET oncogene by concomitant inhibition of receptor and ligand via an antibody-“decoy” strategy

MET, a master gene sustaining "invasive growth," is a relevant target for cancer precision therapy. In the vast majority of tumors, wild-type MET behaves as a "stress-response" gene and relies on the ligand (HGF) to sustain cell "scattering," invasive growth and apoptosis protection (oncogene "expedience"). In this context, concomitant targeting of MET and HGF could be crucial to reach effective inhibition. To test this hypothesis, we combined an anti-MET antibody (MvDN30) inducing "shedding" (i.e., removal of MET from the cell surface), with a "decoy" (i.e., the soluble extracellular domain of the MET receptor) endowed with HGF-sequestering ability. To avoid antibody/decoy interaction-and subsequent neutralization-we identified a single aminoacid in the extracellular domain of MET-lysine 842-that is critical for MvDN30 binding and engineered the corresponding recombinant decoyMET (K842E). DecoyMET(K842E) retains the ability to bind HGF with high affinity and inhibits HGF-induced MET phosphorylation. In HGF-dependent cellular models, MvDN30 antibody and decoyMET(K842E) used in combination cooperate in restraining invasive growth, and synergize in blocking cancer cell "scattering." The antibody and the decoy unbridle apoptosis of colon cancer stem cells grown in vitro as spheroids. In a preclinical model, built by orthotopic transplantation of a human pancreatic carcinoma in SCID mice engineered to express human HGF, concomitant treatment with antibody and decoy significantly reduces metastatic spread. The data reported indicate that vertical targeting of the MET/HGF axis results in powerful inhibition of ligand-dependent MET activation, providing proof of concept in favor of combined target therapy of MET "expedience.

Habitat Preferences of Italian Freshwater Fish: A Systematic Review of Data Availability for Applications of the MesoHABSIM Model

The MesoHABitat SImulation Model (MesoHABSIM) is the preferred method to calculate spatio-temporal variation in the fish habitat availability in Italian rivers. With the aim of improving the applicability of the MesoHABSIM approach in the Italian territory, we carried out a systematic review of physical habitat preferences for 31 freshwater fish species and three freshwater lampreys, representing 75% of the total indigenous freshwater fish community of Italy. Information related to suitable ranges of depth, flow velocity, biotic/abiotic substrates, covers/shelters was collected and summarized for two critical life stages (adult and juvenile) and two bioperiods (rearing/growth and spawning). Overall, 250 publications were reviewed, classified as 206 peer-reviewed papers, 20 books, 7 PhD thesis, and 17 grey literature sources. Our analysis revealed substantial deficits of information about habitat requirements for more than 30% of Italian freshwater fish species. This information is particularly scarce for the most threatened endemic species, especially for their most critical bioperiod (i.e., spawning). With the aim of preserving freshwater fish biodiversity as required in the EU Biodiversity Strategy for 2030 (European Commission, 2020), accurate information on physical habitat requirements for spawning is crucial. As an example application of MesoHABSIM, the collected habitat preference information was used to define and apply mesohabitat suitability criteria for one fish species (Telestes muticellus) in a regulated river reach of Argentina Creek (Province of Imperia, Italy). This analysis demonstrates the potential for applying information from the current review to other fish species

Thromopoietin signaling to chromatin elicits rapid and pervasive epigenome remodeling within poised chromatin architectures.

Thrombopoietin (TPO) is a critical cytokine regulating hematopoietic stem cell maintenance and differentiation into the megakaryocytic lineage. However, the transcriptional and chromatin dynamics elicited by TPO signaling are poorly understood. Here, we study the immediate early transcriptional and cis-regulatory responses to TPO in hematopoietic stem/progenitor cells (HSPCs) and use this paradigm of cytokine signaling to chromatin to dissect the relation between cis- regulatory activity and chromatin architecture. We show that TPO profoundly alters the transcriptome of HSPCs, with key hematopoietic regulators being transcriptionally repressed within 30 minutes of TPO. By examining cis-regulatory dynamics and chromatin architectures, we demonstrate that these changes are accompanied by rapid and extensive epigenome remodeling of cis-regulatory landscapes that is spatially coordinated within topologically associating domains (TADs). Moreover, TPO-responsive enhancers are spatially clustered and engage in preferential homotypic intra- and inter-TAD interactions that are largely refractory to TPO signaling. By further examining the link between cis-regulatory dynamics and chromatin looping, we show that rapid modulation of cis-regulatory activity is largely independent of chromatin looping dynamics. Finally, we show that, although activated and repressed cis-regulatory elements share remarkably similar DNA sequence compositions, transcription factor binding patterns accurately predict rapid cis-regulatory responses to TPO

The long-lasting protective effect of HGF in cardiomyoblasts exposed to doxorubicin requires a positive feed-forward loop mediated by ERK1,2-TIMP1-STAT3

Previous studies showed that the hepatocyte growth factor (HGF)–Met receptor axis plays long-lasting cardioprotection against doxorubicin anti-cancer therapy. Here, we explored the mechanism(s) underlying the HGF protective effect. DNA damage was monitored by histone H2AX phosphorylation and apoptosis by proteolytic cleavage of caspase 3. In doxorubicin-treated H9c2 cardiomyoblasts, the long-lasting cardioprotection is mediated by activation of the Ras/Raf/Mek/Erk (extracellular signal-regulated kinase 1,2) signaling pathway and requires Stat3 (signal transducer and activator of transcription 3) activation. The HGF protection was abrogated by the Erk1,2 inhibitor, PD98059. This translated into reduced Y705 phosphorylation and impaired nuclear translocation of Stat3, showing crosstalk between Erk1,2 and Stat3 signaling. An array of 29 cytokines, known to activate Stat3, was interrogated to identify the molecule(s) linking the two pathways. The analysis showed a selective increase in expression of the tissue inhibitor of metalloproteinases-1 (Timp1). Consistently, inhibition in cardiomyoblasts of Timp1 translation by siRNAs blunted both Stat3 activation and the cardioprotective effect of HGF. Thus, Timp1 is responsible for the generation of a feed-forward loop of Stat3 activation and helps cardiomyocytes to survive during the genotoxic stress induced by anthracyclines