A set of growth arrest-specific genes (gas) whose expression is negatively regulated after serum induction has previously been described (C. Schneider, R. M. King, and L. Philipson, Cell 54:787-793, 1988). The detailed analysis of one of them, gas6, is reported here. gas6 mRNA (2.6 kb) is abundantly expressed in serum-starved (48 h in 0.5% fetal calf serum) NIH 3T3 cells but decreases dramatically after fetal calf serum or basic fibroblast growth factor stimulation. The human homolog ofgas6 was also cloned and sequenced, revealing a high degree of homology and a similar pattern of expression in IMR90 human fibroblasts. Computer analysis of the protein encoded by murine and human gas6 cDNAs showed significant homology (43 and 44% amino acid identity, respectively) to human protein S, a negative coregulator in the blood coagulation pathway. By using an anti-human Gas6 monospecific affinity-purified antibody, we show that the biosynthetic level of human Gas6 fully reflects mRNA expression in IMR9O human fibroblasts. This finding thus defines a new member of vitamin K-dependent proteins that is expressed in many human and mouse tissues and may be involved in the regulation of a protease cascade relevant in growth regulation.Interactions between serine proteases, their substrates, and their inhibitors have largely been exploited during evolution. Protease cascades are not confined to the classical blood coagulation or complement cascade. A network of proteases that control the synthesis or activity of a ligand appears an ideal and finely regulatable mechanism to trigger a rapid response to an extracellular event, with the inherent advantage of powerful amplification. Thrombin, in addition to catalyzing fibrin polymerization, can act as a novel ligand for the recently identified thrombin receptor (61), a member of the seven-transmembrane domain receptor family, possibly mediating other known effects of thrombin, including its role as a mitogen for lymphocytes and fibroblasts (8, 9). Hepatocyte growth factor (scatter factor), which promotes cell division (53) and epithelial morphogenesis (47), is similar in structure to serine proteases (38% amino acid sequence identity with plasminogen), although it lacks proteolytic activity as a result of mutation of two residues in the catalytic triad (31,48). Hepatocyte growth factor is the ligand for the c-met proto-oncogene product (5, 49), a transmembrane 190-kDa heterodimer with tyrosine kinase activity that is widely expressed in normal epithelial tissues (20).Recently, a protease pathway has been shown to play a crucial role in the dorsoventral patterning of Drosophila embryos (36). At least three genes (snake, gastrulation defective, and easter) appear to encode extracellular proteases (7,36). Easter appears to be the ultimate protease that processes spatzle that binds and activates its receptor Toll

Key Points Question What respiratory, functional, and psychological sequalae are associated with recovery from coronavirus disease 2019 (COVID-19)? Findings In this cohort study of 238 patients with COVID-19 hospitalized in an academic hospital in Northern Italy, more than half of participants had a significant reduction of diffusing lung capacity for carbon monoxide or measurable functional impairment and approximately one-fifth of patients had symptoms of posttraumatic stress 4 months after discharge. Meaning These findings suggest that despite virological recovery, a sizable proportion of patients with COVID-19 experienced respiratory, functional, or psychological sequelae months after hospital discharge.

The SARS-CoV-2 pandemic significantly affected oncology practice across the globe. There is uncertainty as to the contribution of patients' demographics and oncologic features to severity and mortality from COVID-19 and little guidance as to the role of anticancer and anti-COVID-19 therapy in this population. In a multicenter study of 890 patients with cancer with confirmed COVID-19, we demonstrated a worsening gradient of mortality from breast cancer to hematologic malignancies and showed that male gender, older age, and number of comorbidities identify a subset of patients with significantly worse mortality rates from COVID-19. Provision of chemotherapy, targeted therapy, or immunotherapy did not worsen mortality. Exposure to antimalarials was associated with improved mortality rates independent of baseline prognostic factors. This study highlights the clinical utility of demographic factors for individualized risk stratification of patients and supports further research into emerging anti-COVID-19 therapeutics in SARS-CoV-2-infected patients with cancer. SIGNIFICANCE: In this observational study of 890 patients with cancer diagnosed with SARS-CoV-2, mortality was 33.6% and predicted by male gender, age ≥65, and comorbidity burden. Delivery of cancer therapy was not detrimental to severity or mortality from COVID-19. These patients should be the focus of shielding efforts during the SARS-CoV-2 pandemic. Research.

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.

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-␣ 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 GSK3␤ phosphorylation and consequent inhibition of NF-B nuclear translocation. Therefore, GAS6 modulates macrophage cytokine secretion, triggering an "anti-inflammatory pathway" involving PI3K/Akt/GSK3␤ and NF-B.

Many coronavirus disease 2019 (Covid-19) survivors show symptoms months after acute illness. The aim of this work is to describe the clinical evolution of Covid-19, one year after discharge. We performed a prospective cohort study on 238 patients previously hospitalized for Covid-19 pneumonia in 2020 who already underwent clinical follow-up 4 months post-Covid-19. 200 consented to participate to a 12-months clinical assessment, including: pulmonary function tests with diffusing lung capacity for carbon monoxide (DLCO); post-traumatic stress (PTS) symptoms evaluation by the Impact of Event Scale (IES); motor function evaluation (by Short Physical Performance Battery and 2 min walking test); chest Computed Tomography (CT). After 366 [363–369] days, 79 patients (39.5%) reported at least one symptom. A DLCO < 80% was observed in 96 patients (49.0%). Severe DLCO impairment (< 60%) was reported in 20 patients (10.2%), related to extent of CT scan abnormalities. Some degree of motor impairment was observed in 25.8% of subjects. 37/200 patients (18.5%) showed moderate-to-severe PTS symptoms. In the time elapsed from 4 to 12 months after hospital discharge, motor function improves, while respiratory function does not, being accompanied by evidence of lung structural damage. Symptoms remain highly prevalent one year after acute illness.

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 multi-lineage (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 Dulbecco's 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, the product of a growth arrest specific (GAS) gene, is the ligand of the tyrosine kinase receptor Axl. GAS6 and Axl are both expressed in endothelial cells, where they are involved in many processes such as leukocyte transmigration through capillaries and neointima formation in injured vessels. Here IntroductionAxl is a 140-kDa protein which belongs to a subfamily of tyrosine kinase receptor (RTK) that includes also Mer and Rse. These receptors are characterized by the presence of 2 immunoglobulinlike domains and 2 fibronectin-type III domains in the extracellular region and a distinctive intracellular kinase domain. 1-3 Axl was first isolated from the DNA of patients with chronic myelogenous leukemia, but subsequently its expression was demonstrated in mammalian cells of vascular, immune, and reproductive systems. 1,[4][5][6] Axl is involved in cell-cell aggregation, 7 in the maintenance of a wide variety of cell types in adult tissues, 6 and in homeostatic regulation of immune system. 8 GAS6, a protein codified by a growth arrest specific gene, is a member of the vitamin K-dependent protein family. GAS6 has 42% amino acid identity to protein S, a serum protein that negatively regulates blood coagulation. GAS6 is composed of characteristic structural motifs: a ␥-carboxylated aminoterminus domain followed by 4 epidermal growth factor-like domains and by a set of tandem G domains similar to those of sex hormone binding globulin. 9 GAS6 binds with different affinities and activates the kinase activity of each Axl family member. 10-12 GAS6 shows the higher affinity for Axl, and its interaction generally triggers antiapoptotic signals, resulting in an augmented cell survival. In some cell types it regulates homotypic and heterotypic adhesion, 4,13 promotes proliferation, 5,14 survival, [15][16][17][18] and motility 19,20 and amplifies the activity of extracellular stimuli. 21,22 Vasculature may be a target of GAS6/Axl axis, being both molecules expressed by endothelial cells (ECs), 4,9 pericytes, 23 and smooth muscle cells. 24 GAS6/Axl interaction is involved in leukocyte transmigration through capillaries, 4,8 in neointima formation in injured vessels, 24 and in EC survival after tumor necrosis factor ␣ (TNF-␣) treatment or acidification. 16,18 Mice lacking the 3 tyrosine kinase receptors, which bind GAS6, show alteration in vasculature survival. 6 By activating specific and partially overlapping genetic programs, ECs play key roles in many processes, as regulation of vascular tone, lipid metabolism, hematopoiesis, inflammation, antigen recognition, thrombosis, hemostasis, and angiogenesis. 25 Angiogenesis refers to the remodeling and maturation of the primitive vascular plexus formed by vasculogenesis during the development and to the sprouting and subsequent stabilization by pericytes of new capillaries from preexisting ones in adult life. 26 Physiologic angiogenesis results from a fine-tuning balance between inducers and inhibitors and achieves a network hierarchically and spatially organized to provide a...