Gian Carlo Avanzi

Selective growth response to IL‐3 of a human leukaemic cell line with megakaryoblastic features

A new human leukaemic cell line (M‐O7) with the phenotypic characteristics of CFU‐mega is described. Its cells are positive for T200 leucocyte common antigen (LCA) and negative with MAbs recognizing T and B cells and mature myelomonocytic antigens. In contrast, they react with MAbs recognizing antigenic determinants common to multilineage (CD13, CD33, CD34) and to bipotent erythromegakaryoblastic (CD36, H25) haemopoietic precursors, and with MAbs specific for platelet glycoproteins (CD41w, CD42w). A small proportion (10%) of the cells were large and multinucleated, and on electron microscopy examination showed peripheral splitting of platelet‐like cytoplasm particles. When transferred to a serum‐free Iscove modified Dulbeccos medium supplemented with human insulin and transferrin, M‐O7 cells stop proliferating. Of the haemopoietic growth factors tested for their ability to restore the proliferative activity of this quiescent population, only rH IL‐3 proved effective. Moreover, it also increased the cloning efficiency in methylcellulose more than any other CSFs. The M‐O7 cell line may provide a valuable tool for the biological assay of IL‐3, and a model for biochemical studies of the megakaryocytic lineage.

Gas6 induces proliferation in prostate carcinoma cell lines expressing the Axl receptor

Axl is a tyrosine kinase receptor and although it is expressed in malignancy such as leukemia, colon cancer, melanoma, endometrial, prostate and thyroid cancers, its role has not been completely elucidated yet and appears to be complex. The ligand of Axl, Gas6, is a 75 KDa multimodular protein with an N‐terminal gamma‐carboxy‐glutamic acid that is essential for binding. Gas6 has a mitogenic effect on several normal cell lines. The receptor Axl is expressed in primary prostate carcinoma and in prostate cancer cell lines as such as PC‐3 and DU 145. We demonstrated a mitogenic activity determined by Gas6/Axl interaction in these undifferentiated metastatic human prostatic cancer cell lines. This effect is proportional to Axl expression, not due to inhibition of apoptosis, and induces AKT and MAPK phosphorylation. However, only MEK phosphorylation seems to be essential for growth signaling. Our results suggest that Axl overexpression and activation by Gas6 could be involved in progression of prostate neoplastic disease.

TNF-α, IL-6, and IL-1 expression is inhibited by GAS6 in monocytes/macrophages

GAS6 protein has been described to be involved in immune modulation in vitro and in vivo. Some of these effects are probably mediated through the involvement of monocytes/macrophages. To understand the role of GAS6 in modulating the immune response, we evaluated the effect on cytokine secretion by monocytes/macrophages and the molecular pathways involved. GAS6 inhibits TNF‐α and IL‐6 secretion by LPS‐stimulated U937 cells and monocytes/machrophages. We evidenced that among GAS6 receptors, only Mer (but not Axl or Tyro3) is expressed on differentiated U937 cells, and its activation is responsible for the reduction of cytokine expression. In immunoblot analysis, Mer was activated after GAS6 stimulation, giving rise to an increased phosphorylation of Akt. We also observed GSK3β phosphorylation and consequent inhibition of NF‐κB nuclear translocation. Therefore, GAS6 modulates macrophage cytokine secretion, triggering an “anti‐inflammatory pathway” involving PI3K/Akt/GSK3β and NF‐κB.

Interleukin 3 enhances the cytotoxic activity of 1-β-d-arabinofuranosylcytosine (ara-C) on acute myeloblastic leukaemia (AML) cells

We have evaluated the possibility of enhancing the cell killing effect of ara‐C on AML blasts by increasing their proliferative activity with haemopoietic growth factors. Leukaemic cells from 10 AML patients were incubated for 3 d in liquid culture in the presence or in the absence of the human recombinant growth factors IL‐1β (5 U/ml) and IL‐3 (3 U/ml), and subsequently exposed to ara‐C (3 μ/ml) for the last 24 h. The number of residual leukaemic stem cells was evaluated by a clonogenic assay in semisolid medium. The results showed that ara‐C exposure inhibits the proliferation of a higher proportion of clonogenic cells in cultures pretreated with growth factors than in the controls (mean inhibitory values: in the absence of growth factors = 49.8%: with IL‐1β=58.3%; with IL‐3 78.9%) The effect was statistically significant only when IL‐3 was used as a growth factor.

The expression pattern of inflammatory mediators in cerebrospinal fluid differentiates Guillain–Barré syndrome from chronic inflammatory demyelinating polyneuropathy

INTRODUCTION Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) share histopathological features but display different disease courses; we measured the concentration of 50 inflammatory mediators in the cerebrospinal fluid (CSF) of patients with either of these diseases. PATIENTS AND METHODS CSF samples were collected during a diagnostic lumbar puncture and stored at -30 degrees C. We analyzed the CSF of nine subjects with GBS; eight with CIDP; eight with diabetic polyneuropathy (DP) and seven with headache (controls). Fifty inflammatory mediators were simultaneously measured with a multiplex bead-based ELISA on a Suspension Array System. After Bonferronis correction for repeated measures, non-parametric variance and post hoc test were calculated. RESULTS Thirty-two inflammatory mediators were expressed. The median concentration of IL-6, IL-9, IL-15, IL-18, CCL4, CXCL1, LIF, MIF, PDGFbb, IFN-gamma2, IL-2ra, IL-12(p40), IL-16, SCGF-b, TRAIL, FGF, G-CSF, GM-CSF, and M-CSF was not different among groups (variance: n.s.). The median concentration of CCL2, CCL7, CCL27, CXCL9, CXCL10, CXCL12, ICAM-1, VCAM1 and VEGF was higher in CIDP and GBS compared with controls (p<0.002). The median concentration of IL-8 and IL-1ra was higher in GBS than CIDP or DP or controls, whereas stem cell factor (SCF) and hepatocyte growth factor (HGF) were higher in CIDP than GBS or DP or controls (p<0.002). DISCUSSION Mediators of the recruitment and activation of lymphocytes and monocytes are expressed in the CSF of CIDP and GBS. IL-8 and IL-1ra are characteristic of GBS, whereas growth factors (SCF, HGF) of CIDP are possibly related to chronicity or to the survival/repair processes of neurons.

Development and Validation of an ELISA Method for Detection of Growth Arrest Specific 6 (GAS6) Protein in Human Plasma

Abstract Gas6 protein is possibly involved in human diseases, but a validated plasma assay is lacking. So, we developed a sandwich enzyme‐linked immunosorbent assay (ELISA) method using commercially available reagents. An appropriate plasma‐based matrix was prepared to optimize the assay. The ELISA method showed inter‐ and intra‐assay coefficients of variation lower than 15%. Recoveries all fell within 15% of expected values. Plasma Gas6 concentration in 61 healthy donors was 20.3±3.8 ng/mL. Our assay meets FDA requirements for precision and accuracy for the validation of bioanalytical methods and it is suitable for research or diagnostic purposes.

An erythroid and megakaryocytic common precursor cell line (B1647) expressing both c‐mpl and erythropoietin receptor (Epo‐R) proliferates and modifies globin chain synthesis in response to megakaryocyte growth and development factor (MGDF) but not to erythropoietin (Epo)

A human megakaryocyte cell line (B1647) has been established from bone marrow cells obtained from a patient with acute myelogenous leukaemia (FAB M2). The cells were CD34−, CD33+, HLA‐DR+, CD38+, and expressed the immunophenotypic markers of the megakaryocyte lineage (CD41 and von Willebrand factor). Moreover the cells expressed the c‐mpl (thrombopoietin receptor) mRNA and protein. On the other hand, the B1647 cells also possessed erythroid lineage characteristics: the vast majority of cells were glycophorin positive, and about 10% of unstimulated cells stained with an anti‐globin γ chain MoAb. In addition, S1 protection analysis demonstrated expression of β‐globin mRNA, and Epo receptor (Epo‐R) protein was detected by cytofluorimetric assay. Several growth factors, when tested alone or in combination, failed to influence the B1647 cell growth. A significant increase of cell proliferation was observed only after the addition, in serum‐free culture, of recombinant human megakaryocyte growth development factor (MGDF), a recombinant c‐mpl ligand encompassing the receptor‐binding domain and identical to thrombopoietin (TPO), at concentrations ranging from 0.01 to 1 ng/ml. Interestingly, MGDF failed to induce megakaryocytic differentiation of the B1647 cells, but significantly increased the synthesis of the globin γ‐chain.

Elevation of Gas6 protein concentration in cerebrospinal fluid of patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

INTRODUCTION Gas6 enhances survival of Schwann cells and neurons in vitro and participates in autoimmunity in animal models. Since its concentration in human cerebrospinal fluid (CSF) is unknown, we measured it in samples from patients with non-inflammatory/non-autoimmune neurological diseases (NINAD) and autoimmune polyneuropathies. MATERIALS AND METHODS Samples collected after informed consent during diagnostic lumbar puncture in the period 1999-2006 were stored at -30 degrees C. We considered subjects with NINAD (stroke, ALS, headache, psychiatric conditions simulating neurological diseases, otologic dizziness) or with Guillain-Barré syndrome (GBS) or CIDP. CSF and plasma total protein and age were obtained from clinical records. Gas6 was measured with an ELISA developed and validated in our laboratory (inter-, intra-assay CVs <10%, recovery 96%). Variance, Tukeys post-hoc test, regression were calculated with a statistical software (Statsoft). RESULTS Mean Gas6 concentration in patients with NINAD was 6.5+/-2.4 ng/ml, 7.2+/-2.6 ng/ml in GBS and significantly higher (11.5+/-1.7 ng/ml) in CIDP than in the other conditions (post-hoc, p<0.005). It was not related to age, CSF total proteins or to CSF/plasma ratio of total proteins (regression, p>0.1). CONCLUSIONS Gas6 is detectable in CSF and may be involved in chronic autoimmune demyelination or myelin repair.

Suicide attempts and emergency room psychiatric consultation

BackgroundSuicidal behaviours are major public health concerns worldwide. They are associated with risk factors that vary with age and gender, occur in combination, and may change over time. The aim of our study was to investigate how frequently patients visiting a hospital emergency room (ER) require a psychiatric consultation for attempted suicide, and to outline the characteristics of this population.MethodsDeterminants of emergency room visits for psychiatric reasons were studied prospectively from 2008 to 2011 at the “Maggiore” Hospital in Novara.Results280 out of 1888 patients requiring psychiatric consultation were referred to the ER because of suicide attempt. Suicide attempters were more often female. The rate of suicide attempters among Italian people was 14.2%, compared to 19.5% in foreigners. Subjects living with parents or own family and those having a permanent job had a higher frequency of suicide attempt. Suicide attempts were more frequent among patients with a history of psychiatric disorders; nonetheless, suicide attempts were more common among those who had not previously been hospitalized in a psychiatric ward or were not under the care of a psychiatrist. The multivariate analysis found that female gender was a risk factor for suicide attempt, while being in the colder months of the year and, surprisingly, unemployment were protective factors.ConclusionsA better understanding of patients referring to the ER due to attempted suicide may allow the identification of at-risk subjects and the implementation of targeted treatment approaches.

Novel Axl-driven signaling pathway and molecular signature characterize high-grade ovarian cancer patients with poor clinical outcome

High-grade epithelial ovarian cancer (HGEOC) is a clinically diverse and molecularly heterogeneous disease comprising subtypes with distinct biological features and outcomes. The receptor tyrosine kinases, expressed by EOC cells, and their ligands, present in the microenvironment, activate signaling pathways, which promote EOC cells dissemination. Herein, we established a molecular link between the presence of Gas6 ligand in the ascites of HGEOCs, the expression and activation of its receptor Axl in ovarian cancer cell lines and biopsies, and the progression of these tumors. We demonstrated that Gas6/Axl signalling converges on the integrin β3 pathway in the presence of the adaptor protein p130Cas, thus inducing tumor cell adhesion to the extracellular matrix and invasion. Accordingly, Axl and p130Cas were significantly co-expressed in HGEOC samples. Clinically, we identified an Axl-associated signature of 62 genes able to portray the HGEOCs with the shortest overall survival. These data biologically characterize a group of HGEOCs and could help guide a more effective therapeutic approach to be taken for these patients.