QUALITY OF LIFE, PHYSICAL ACTIVITY LEVEL AND DIETARY BEHAVIORS OF PARENTS OF CHILDREN WITH CANCER

The quality of life of parents of children with cancer has been a topic of research in the international literature, whereas no research data yet for parents in Greece has been noticed. The purpose of this study was to examine the impact of childhood cancer on the quality of life, dietary habits, and the level of participation in physical activities of their parents. The sample of the present study was 24 parents (14 women, 10 men), from FLOGA foundation from different regions of Greece aged 38-60 years. To conduct the present study, 3 questionnaires were administered to parents, that is, the SF-36 Quality of Life Questionnaire (Ware, Kosinski, & Keller, 2001), the Physical Activity (PA) questionnaire (Godin & Shephard, 1985) and the "Dietary Behaviors" questionnaire (Bebetsos et al., 2000). The statistical analysis involved the use of the Statistical Package for Social Sciences (SPSS 29.00). The results of the research showed statistically significant differences based on the age of both parents and children, the marital status of the parents, the existence of parental health problems and parental health status and profession. Overall, the positive factors related to parental quality of life were identified and discussed. Future research with larger samples is needed to draw in-depth conclusions.  Article visualizations

PHYSICAL ACTIVITY, ANXIETY, DEPRESSION AND SMOKING HABITS OF PARENTS HAVING CHILDREN WITH CANCER

Parents of children with cancer are a group of people who have been involved in international research, whereas no relative research in Greece has been noticed so far. The purpose of this study was to investigate the effects of children’s cancer on their parents of affected children in terms of anxiety and depression levels and adoption of health behaviors including exercise participation and smoking. The study sample consisted of 24 people (14 women and 10 men) aged 38 to 60 years. Research instruments included the use of 3 questionnaires distributed to the participants, that is, the questionnaire of Beacke et al. (1982) for the assessment of physical activity, Heatherton et al. (1991) test for the assessment of nicotine dependence and Zigmond and Snaith (1983) test for the assessment of anxiety and depression. The statistical analysis was performed using the SPSS 29.0 Statistical Package. The results showed fathers exhibiting higher levels of stress and depression compared to mothers. Additional statistically significant differences were also noted in parental adoption of health behaviors based on different demographic characteristics. Future researches with larger samples are needed to further draw representative conclusions.  Article visualizations

Synthesis and characterization of hypoxia-mimicking bioactive glasses for skeletal regeneration

The cellular response to hypoxia (low oxygen pressure) is vital for skeletal tissue development and regeneration. Numerous processes, including progenitor cell recruitment, differentiation and angiogenesis, are activated via the hypoxia pathway. Novel materials-based strategies designed to activate the hypoxia pathway are therefore of great interest for orthopaedic tissue engineering. Resorbable bioactive glasses (BGs) were developed to activate the hypoxia pathway by the controlled release of cobalt ions (at physiological relevant concentrations) whilst controlling BG apatite-forming ability. Two series of soda-lime-phosphosilicate glasses were synthesised with increasing concentrations of cobalt. Compositions were calculated to maintain constant network connectivity (2.13) by considering that cobalt is taking part in the network in the first series, and is acting as a network modifier in the second series. Mg2+ and Zn2+ were added to one of the Co2+-containing glasses to inhibit HCA formation. The presence of HCA formation is undesirable for the use of BG in soft tissues e. g. cartilage. Cobalt was present in both the silicate and phosphate phases of the BG. In addition, evidence was found that it plays a dual role in the silicate phase, entering the network as well as disrupting it as a network modifying oxide. Consistent with this dual role, the presence of cobalt in the BG was shown to decrease ion release. HCA formation was delayed with cobalt addition as well as incorporation of Mg2+ and Zn2+ into the BGs. Importantly, cobalt release was found to be proportional to cobalt content of the BGs enabling the controlled delivery of cobalt in therapeutically active doses

Ubiquitin-specific protease-like 1 (USPL1) is a SUMO isopeptidase with essential, non-catalytic functions.

Isopeptidases are essential regulators of protein ubiquitination and sumoylation. However, only two families of SUMO isopeptidases are at present known. Here, we report an activity-based search with the suicide inhibitor haemagglutinin (HA)-SUMO-vinylmethylester that led to the identification of a surprising new SUMO protease, ubiquitin-specific protease-like 1 (USPL1). Indeed, USPL1 neither binds nor cleaves ubiquitin, but is a potent SUMO isopeptidase both in vitro and in cells. C13orf22l—an essential but distant zebrafish homologue of USPL1—also acts on SUMO, indicating functional conservation. We have identified invariant USPL1 residues required for SUMO binding and cleavage. USPL1 is a low-abundance protein that colocalizes with coilin in Cajal bodies. Its depletion does not affect global sumoylation, but causes striking coilin mislocalization and impairs cell proliferation, functions that are not dependent on USPL1 catalytic activity. Thus, USPL1 represents a third type of SUMO protease, with essential functions in Cajal body biology

Casein kinase 1 regulates human hypoxia-inducible factor HIF-1

Hypoxia-inducible factor 1 (HIF-1), a transcriptional activator that mediates cellular response to hypoxia and a promising target of anticancer therapy, is essential for adaptation to low oxygen conditions, embryogenesis and tumor progression. HIF-1 is a heterodimer of HIF-1alpha, expression of which is controlled by oxygen levels as well as by various oxygen-independent mechanisms, and HIF-1beta (or ARNT), which is constitutively expressed. In this work, we investigate the phosphorylation of the N-terminal heterodimerization (PAS) domain of HIF-1alpha and identify Ser247 as a major site of in vitro modification by casein kinase 1delta (CK1delta). Mutation of this site to alanine, surprisingly, enhanced the transcriptional activity of HIF-1alpha, a result phenocopied by inhibition or small interfering RNA (siRNA)-mediated silencing of CK1delta under hypoxic conditions. Conversely, overexpression of CK1delta or phosphomimetic mutation of Ser247 to aspartate inhibited HIF-1alpha activity without affecting its stability or nuclear accumulation. Immunoprecipitation and in vitro binding experiments suggest that CK1-dependent phosphorylation of HIF-1alpha at Ser247 impairs its association with ARNT, a notion also supported by modeling the structure of the complex between HIF-1alpha and ARNT PAS-B domains. We suggest that modification of HIF-1alpha by CK1 represents a novel mechanism that controls the activity of HIF-1 during hypoxia by regulating the interaction between its two subunits.J Cell Sc

Ubiquitin‐specific protease‐like 1 (USPL1) is a SUMO isopeptidase with essential, non‐catalytic functions

Isopeptidases are essential regulators of protein ubiquitination and sumoylation. However, only two families of SUMO isopeptidases are at present known. Here, we report an activity-based search with the suicide inhibitor haemagglutinin (HA)-SUMO-vinylmethylester that led to the identification of a surprising new SUMO protease, ubiquitin-specific protease-like 1 (USPL1). Indeed, USPL1 neither binds nor cleaves ubiquitin, but is a potent SUMO isopeptidase both in vitro and in cells. C13orf22l—an essential but distant zebrafish homologue of USPL1—also acts on SUMO, indicating functional conservation. We have identified invariant USPL1 residues required for SUMO binding and cleavage. USPL1 is a low-abundance protein that colocalizes with coilin in Cajal bodies. Its depletion does not affect global sumoylation, but causes striking coilin mislocalization and impairs cell proliferation, functions that are not dependent on USPL1 catalytic activity. Thus, USPL1 represents a third type of SUMO protease, with essential functions in Cajal body biology

A European network to fine-tune the proteome

Publisher Copyright: © 2024 The Author(s)Proteins are essential molecular actors in every cellular process. From their synthesis to their degradation, they are subject to continuous quality control mechanisms to ensure that they fulfil cellular needs in proper and timely fashion. Proteostasis is a key process allowing cells or organisms to maintain an appropriate but dynamic equilibrium of their proteome (the ensemble of all their proteins). It relies on multiple mechanisms that together control the level, fate and function of individual proteins, and ensure elimination of abnormal ones. The proteostasis network is essential for development and adaptation to environmental changes or challenges. Its dysfunctions can lead to accumulation of deleterious proteins or, conversely, to excessive degradation of beneficial ones, and are implicated in many diseases such as cancers, neurodegeneration, or developmental and aging disorders. Manipulating this network to control abundance of selected target proteins is therefore a strategy with enormous therapeutic or biotechnological potential. The ProteoCure COST Action gathers more than 350 researchers and their teams (31 countries represented) from the academic, clinical, and industrial sectors, who share the conviction that our understanding of proteostasis is mature enough to develop novel and highly specific therapies based on selective tuning of protein levels. Towards this objective, the Action organizes community-building activities to foster synergies among its participants and reinforce training of the next generation of European researchers. Its ambition is to function as a knowledge-based network and a creative exchange hub on normal and pathologic proteostasis, focusing on developing innovative tools modulating the level of specific protein(s).publishersversioninpres

Investigation of the activation mechanism of the hypoxia inducible factor HIF-1a in vitro and in primary cultures of airway smooth muscle cells

The present study deals with the investigation of the molecular mechanisms involved in the regulation and activation of the hypoxia inducible factor 1α (HIF-1α). At first, we examined the induction mechanisms of HIF-1α in primary cultures of airway smooth muscle (ASM) cells. The use of specific inhibitors revealed that ΗΙF- 1α, in ASM cells that are cultured in the absence of fetal bovine serum and thus obtain their “differentiated” contractile apparatus, is induced by two distinct mechanisms. The first mechanism that is induced by cobalt is the stabilization of the protein due to a possible inhibition of prolyl-hydroxylases and the second one that is induced by serum, involves enhanced synthesis of HIF-1α through transcription, translation and involvement of the PI-3K pathway. On the contrary, cobalt induces HIF-1α mainly through his protein synthesis, in “synthetic” ASM cells, that are cultured in the presence of serum, by using the activated PI-3K pathway. In order to further study the molecular properties of HIF-1α in vitro we used recombinant full length HIF-1α that was produced for the first time in bacteria. This unmodified form of HIF-1α was able to form a stable heterodimer with the second subunit of HIF-1 (ARNT) when both proteins were co-expressed in E. coli. The reconstituted heterodimer exhibited specific DNA binding activity. The amino-terminal regions of the two subunits were bound to DNA but this activity was affected by the carboxy-terminal regions of the two proteins. Furthermore, during the study of interaction of recombinant HIF-1α with p42-MAPK, the exact phosphorylation positions of HIF-1α were revealed. Finally, we studied the unknown nuclear transport mechanism of HIF-1α and we showed that importins 4 and 7 are responsible for HIF-1α import and thus define two distinct import pathways for the protein.Στην παρούσα διδακτορική διατριβή μελετήθηκαν οι μοριακοί μηχανισμοί ρύθμισης και ενεργοποίησης του παράγοντα που επάγεται από την υποξία ΗΙF-1α. Αρχικά διερευνήθηκε ο μηχανισμός επαγωγής του HIF-1α σε λεία μυϊκά κύτταρα αεραγωγών (ΛΜΚΑ). Η χρήση αναστολέων κυτταρικών μονοπατιών αποκάλυψε πως η επαγωγή του HIF-1α σε ΛΜΚΑ που καλλιεργούνται απουσία ορού και παρουσιάζουν τον επιμήκη «διαφοροποιημένο» φαινότυπο μπορεί να επιτευχθεί μέσω δύο τουλάχιστον μηχανισμών. Ο πρώτος μηχανισμός που ενεργοποιείται από το κοβάλτιο οδηγεί στη σταθεροποίηση του HIF-1α πιθανά μέσω αναστολής των πρόλυλο-υδροξυλασών ενώ ο δεύτερος που ενεργοποιείται από τον ορό ενέχει την αύξηση της σύνθεσης του μέσω μεταγραφής και μετάφρασης ενώ φαίνεται να εμπλέκει και το μονοπάτι της PI-3K. Αντίθετα σε «συνθετικά» ΛΜΚΑ που καλλιεργούνται συνεχώς παρουσία ορού το κοβάλτιο επάγει τον HIF-1α κυρίως μέσω αύξησης της μετάφρασης του mRNA του χρησιμοποιώντας το μονοπάτι της PI-3K που είναι ήδη ενεργοποιημένο από τον ορό. Για να διερευνηθεί περαιτέρω ο μηχανισμός ενεργοποίησης του HIF-1α in vitro χρησιμοποιήθηκε ανασυνδυασμένος HIF-1α πλήρους μεγέθους που παράχθηκε για πρώτη φορά, σε βακτήρια. Δείχθηκε πως ο ανασυνδυασμένος HIF-1α έχει τη δυνατότητα να συνδέεται σταθερά με τον συμπαράγοντα του ARNT μόνο όταν οι δυο πρωτεΐνες συνεκφραστούν στα ίδια E.coli κύτταρα. Επιπλέον, το σύμπλοκο που προκύπτει είναι ικανό για ειδική σύνδεση σε αλληλουχία του DNA που περιέχει τα στοιχεία απόκρισης στην υποξία (HRE). H σύνδεση γίνεται μέσω των αμινοτελικών άκρων των δύο υπομονάδων αλλά επηρεάζεται και από τα καρβοξυτελικά άκρα τους. Ο μη τροποποιημένος ανασυνδυασμένος HIF-1α χρησιμοποιήθηκε επίσης στη μελέτη της φωσφορυλίωσης του από την p42 MAP κινάση. Με αυτόν τον τρόπο αποκαλύφθηκαν για πρώτη φορά οι ακριβείς θέσεις φωσφορυλίωσης του από τη συγκεκριμένη κινάση. Τέλος μελετήθηκε ο άγνωστος μέχρι στιγμής μηχανισμός μεταφοράς του HIF-1α στον πυρήνα και δείχθηκε ότι οι ιμπορτίνες 4 και 7 είναι υπεύθυνες για την είσοδο του στον πυρήνα υποδεικνύοντας έτσι την ύπαρξη δύο διαφορετικών μονοπατιών εισόδου

Specific Inhibition of HIF Activity: Can Peptides Lead the Way?

Reduced oxygen availability (hypoxia) is a characteristic of many disorders including cancer. Central components of the systemic and cellular response to hypoxia are the Hypoxia Inducible Factors (HIFs), a small family of heterodimeric transcription factors that directly or indirectly regulate the expression of hundreds of genes, the products of which mediate adaptive changes in processes that include metabolism, erythropoiesis, and angiogenesis. The overexpression of HIFs has been linked to the pathogenesis and progression of cancer. Moreover, evidence from cellular and animal models have convincingly shown that targeting HIFs represents a valid approach to treat hypoxia-related disorders. However, targeting transcription factors with small molecules is a very demanding task and development of HIF inhibitors with specificity and therapeutic potential has largely remained an unattainable challenge. Another promising approach to inhibit HIFs is to use peptides modelled after HIF subunit domains known to be involved in protein–protein interactions that are critical for HIF function. Introduction of these peptides into cells can inhibit, through competition, the activity of endogenous HIFs in a sequence and, therefore also isoform, specific manner. This review summarizes the involvement of HIFs in cancer and the approaches for targeting them, with a special focus on the development of peptide HIF inhibitors and their prospects as highly-specific pharmacological agents.</jats:p