The polyamine/hypusine signaling promotes colorectal cancer cell growth by regulating c-Myc translation

Colorectal cancer is the most frequent malignancy of the gastroenteric system and it is the third most common cancer among males and the second among women. The development of colorectal cancer is determined by progressive genetic and epigenetic alterations which, starting from the formation of adenomatous polyps, lead to the formation of malignant lesions. The mutations include pathways regulatory genes involved in development, proliferation and survival of cancer cells, such as APC/beta catenin, Ras-BRAF/MAPK, p53, pI3K/AKT and SMAD/TGFbeta. In most cases, the aberrant activation of these pathways converges in the overexpression of the oncogene c-Myc. Therefore, inhibition of this oncogene could represent an effective anti-cancer strategy in many types of colorectal cancer. Previous studies have shown that the hypusination, post-translation modification that activates the elongation factor EIF5A, plays an important role in tumour progression. This modification is mediated by two enzymes: DHPS and DOHH that use spermidine as a substrate, an over-expressed polyamine in many solid tumours. The aim of this project was to understand the role of hypusination pathway in CRC and the effect of its pharmacological and genetical targeting. We have shown how inhibition of the EIF5A hypusination, induced by treatment with GC7 or by gene ablation of DHPS in colorectal cancer cells (HCT116, HT29, SW480 and LoVo), has a strong anti-proliferative effect on CRC cells in vitro and in vivo. By analysing the activation status of major pathways involved in tumour onset and progression, we have shown that the DHPS-EIF5A1 axis regulates c-Myc protein levels. The regulation does not alter the mRNA levels or the stability of c-Myc but its translation. Through multi/single site mutagenesis experiments we identified the region of c-Myc involved in EIF5A-mediated regulation. In conclusion, this work shows that the oncogene c-Myc is a translation target of the elongation factor EIF5A; the inhibition of the hypusination causes the blocking of the translation of this oncogene and a decrease in colorectal cancer cells proliferation in vitro and in vivo. Such evidence could be the basis for new therapeutic approaches in colorectal tumours based on the blocking of c-Myc translation by DHPS pharmacological or genetical inhibition.

Mitogen-activated kinase kinase kinase 1 inhibits hedgehog signaling and medulloblastoma growth through GLI1 phosphorylation

The aberrant activation of hedgehog (HH) signaling is a leading cause of the development of medulloblastoma, a pediatric tumor of the cerebellum. The FDA‑approved HH inhibitor, Vismodegib, which targets the transmembrane transducer SMO, has shown limited efficacy in patients with medulloblastoma, due to compensatory mechanisms that maintain an active HH‑GLI signaling status. Thus, the identification of novel actionable mechanisms, directly affecting the activity of the HH‑regulated GLI transcription factors is an important goal for these malignancies. In this study, using gene expression and reporter assays, combined with biochemical and cellular analyses, we demonstrate that mitogen‑activated kinase kinase kinase 1 (MEKK1), the most upstream kinase of the mitogen‑activated protein kinase (MAPK) phosphorylation modules, suppresses HH signaling by associating and phosphorylating GLI1, the most potent HH‑regulated transcription factor. Phosphorylation occurred at multiple residues in the C‑terminal region of GLI1 and was followed by an increased association with the cytoplasmic proteins 14‑3‑3. Of note, the enforced expression of MEKK1 or the exposure of medulloblastoma cells to the MEKK1 activator, Nocodazole, resulted in a marked inhibitory effect on GLI1 activity and tumor cell proliferation and viability. Taken together, the results of this study shed light on a novel regulatory mechanism of HH signaling, with potentially relevant implications in cancer therapy

Selective targeting of HDAC1/2 elicits anticancer effects through Gli1 acetylation in preclinical models of SHH Medulloblastoma.

SHH Medulloblastoma (SHH-MB) is a pediatric brain tumor characterized by an inappropriate activation of the developmental Hedgehog (Hh) signaling. SHH-MB patients treated with the FDA-approved vismodegib, an Hh inhibitor that targets the transmembrane activator Smoothened (Smo), have shown the rapid development of drug resistance and tumor relapse due to novel Smo mutations. Moreover, a subset of patients did not respond to vismodegib because mutations were localized downstream of Smo. Thus, targeting downstream Hh components is now considered a preferable approach. We show here that selective inhibition of the downstream Hh effectors HDAC1 and HDAC2 robustly counteracts SHH-MB growth in mouse models. These two deacetylases are upregulated in tumor and their knockdown inhibits Hh signaling and decreases tumor growth. We demonstrate that mocetinostat (MGCD0103), a selective HDAC1/HDAC2 inhibitor, is a potent Hh inhibitor and that its effect is linked to Gli1 acetylation at K518. Of note, we demonstrate that administration of mocetinostat to mouse models of SHH-MB drastically reduces tumor growth, by reducing proliferation and increasing apoptosis of tumor cells and prolongs mouse survival rate. Collectively, these data demonstrate the preclinical efficacy of targeting the downstream HDAC1/2-Gli1 acetylation in the treatment of SHH-MB

Low in‑hospital mortality rate in patients with COVID‑19 receiving thromboprophylaxis: data from the multicentre observational START‑COVID Register

Abstract COVID-19 infection causes respiratory pathology with severe interstitial pneumonia and extra-pulmonary complications; in particular, it may predispose to thromboembolic disease. The current guidelines recommend the use of thromboprophylaxis in patients with COVID-19, however, the optimal heparin dosage treatment is not well-established. We conducted a multicentre, Italian, retrospective, observational study on COVID-19 patients admitted to ordinary wards, to describe clinical characteristic of patients at admission, bleeding and thrombotic events occurring during hospital stay. The strategies used for thromboprophylaxis and its role on patient outcome were, also, described. 1091 patients hospitalized were included in the START-COVID-19 Register. During hospital stay, 769 (70.7%) patients were treated with antithrombotic drugs: low molecular weight heparin (the great majority enoxaparin), fondaparinux, or unfractioned heparin. These patients were more frequently affected by comorbidities, such as hypertension, atrial fibrillation, previous thromboembolism, neurological disease,and cancer with respect to patients who did not receive thromboprophylaxis. During hospital stay, 1.2% patients had a major bleeding event. All patients were treated with antithrombotic drugs; 5.4%, had venous thromboembolism [30.5% deep vein thrombosis (DVT), 66.1% pulmonary embolism (PE), and 3.4% patients had DVT + PE]. In our cohort the mortality rate was 18.3%. Heparin use was independently associated with survival in patients aged ≥ 59 years at multivariable analysis. We confirmed the high mortality rate of COVID-19 in hospitalized patients in ordinary wards. Treatment with antithrombotic drugs is significantly associated with a reduction of mortality rates especially in patients older than 59 years

Polyamine Metabolism as a Therapeutic Target in Hedgehog-Driven Basal Cell Carcinoma and Medulloblastoma

Hedgehog (Hh) signaling is a critical developmental regulator and its aberrant activation, due to somatic or germline mutations of genes encoding pathway components, causes Basal Cell Carcinoma (BCC) and medulloblastoma (MB). A growing effort has been devoted at the identification of druggable vulnerabilities of the Hedgehog signaling, leading to the identification of various compounds with variable efficacy and/or safety. Emerging evidence shows that an aberrant polyamine metabolism is a hallmark of Hh-dependent tumors and that its pharmacological inhibition elicits relevant therapeutic effects in clinical or preclinical models of BCC and MB. We discuss here the current knowledge of polyamine metabolism, its role in cancer and the available targeting strategies. We review the literature about the connection between polyamines and the Hedgehog signaling, and the potential therapeutic benefit of targeting polyamine metabolism in two malignancies where Hh pathways play a well-established role: BCC and MB

Lower-Limb Joint Coordination Pattern in Obese Subjects

The coordinative pattern is an important feature of locomotion that has been studied in a number of pathologies. It has been observed that adaptive changes in coordination patterns are due to both external and internal constraints. Obesity is characterized by the presence of excess mass at pelvis and lower-limb areas, causing mechanical constraints that central nervous system could manage modifying the physiological interjoint coupling relationships. Since an altered coordination pattern may induce joint diseases and falls risk, the aim of this study was to analyze whether and how coordination during walking is affected by obesity. We evaluated interjoint coordination during walking in 25 obese subjects as well as in a control group. The time-distance parameters and joint kinematics were also measured. When compared with the control group, obese people displayed a substantial similarity in joint kinematic parameters and some differences in the time-distance and in the coupling parameters. Obese subjects revealed higher values in stride-to-stride intrasubjects variability in interjoint coupling parameters, whereas the coordinative mean pattern was unaltered. The increased variability in the coupling parameters is associated with an increased risk of falls and thus should be taken into account when designing treatments aimed at restoring a normal locomotion pattern

Spinocerebellar ataxia type 3 in Italy. time to change mind

In a review on the global epidemiology of hereditary ataxias published in this journal in 2014, it has been reported that spinocerebellar ataxia type 3 (SCA3) is considered to be absent in Italy [1]. Similar results were also published in a prevalence study in the province of Padua in 2004 [2]. However, isolated Italian SCA3 families have been previously reported [3,4]. Here we report the cases of 3 additional Italian SCA3 patients

Blockade of EIF5A hypusination limits colorectal cancer growth by inhibiting MYC elongation

Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APC Min/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy