Targeting the DNA damage response to overcome cancer drug resistance in glioblastoma

Glioblastoma multiforme (GBM) is one of the most recalcitrant brain tumors characterized by a tumor microenvironment (TME) that strongly supports GBM growth, aggressiveness, invasiveness, and resistance to therapy. Importantly, a common feature of GBM is the aberrant activation of receptor tyrosine kinases (RTKs) and of their downstream signaling cascade, including the non-receptor tyrosine kinase SRC. SRC is a central downstream intermediate of many RTKs, which triggers the phosphorylation of many substrates, therefore, promoting the regulation of a wide range of different pathways involved in cell survival, adhesion, proliferation, motility, and angiogenesis. In addition to the aforementioned pathways, SRC constitutive activity promotes and sustains inflammation and metabolic reprogramming concurring with TME development, therefore, actively sustaining tumor growth. Here, we aim to provide an updated picture of the molecular pathways that link SRC to these events in GBM. In addition, SRC targeting strategies are discussed in order to highlight strengths and weaknesses of SRC inhibitors in GBM management, focusing our attention on their potentialities in combination with conventional therapeutic approaches (i.e., temozolomide) to ameliorate therapy effectiveness

Targeting the DNA damage response to overcome cancer drug resistance in glioblastoma

Glioblastoma multiforme (GBM) is one of the most recalcitrant brain tumors characterized by a tumor microenvironment (TME) that strongly supports GBM growth, aggressiveness, invasiveness, and resistance to therapy. Importantly, a common feature of GBM is the aberrant activation of receptor tyrosine kinases (RTKs) and of their downstream signaling cascade, including the non-receptor tyrosine kinase SRC. SRC is a central downstream intermediate of many RTKs, which triggers the phosphorylation of many substrates, therefore, promoting the regulation of a wide range of different pathways involved in cell survival, adhesion, proliferation, motility, and angiogenesis. In addition to the aforementioned pathways, SRC constitutive activity promotes and sustains inflammation and metabolic reprogramming concurring with TME development, therefore, actively sustaining tumor growth. Here, we aim to provide an updated picture of the molecular pathways that link SRC to these events in GBM. In addition, SRC targeting strategies are discussed in order to highlight strengths and weaknesses of SRC inhibitors in GBM management, focusing our attention on their potentialities in combination with conventional therapeutic approaches (i.e., temozolomide) to ameliorate therapy effectiveness

SRC kinase in glioblastoma: news from an old acquaintance

Glioblastoma multiforme (GBM) is one of the most recalcitrant brain tumors characterized by a tumor microenvironment (TME) that strongly supports GBM growth, aggressiveness, invasiveness, and resistance to therapy. Importantly, a common feature of GBM is the aberrant activation of receptor tyrosine kinases (RTKs) and of their downstream signaling cascade, including the non-receptor tyrosine kinase SRC. SRC is a central downstream intermediate of many RTKs, which triggers the phosphorylation of many substrates, therefore, promoting the regulation of a wide range of different pathways involved in cell survival, adhesion, proliferation, motility, and angiogenesis. In addition to the aforementioned pathways, SRC constitutive activity promotes and sustains inflammation and metabolic reprogramming concurring with TME development, therefore, actively sustaining tumor growth. Here, we aim to provide an updated picture of the molecular pathways that link SRC to these events in GBM. In addition, SRC targeting strategies are discussed in order to highlight strengths and weaknesses of SRC inhibitors in GBM management, focusing our attention on their potentialities in combination with conventional therapeutic approaches (i.e., temozolomide) to ameliorate therapy effectiveness

Development project of the Maltar Boarding House and Hotel and its contribution to hotel industry and tourism in Varaždin

Iz godine u godinu Republika Hrvatska bilježi sve veći porast broja turističkih dolazaka i noćenja što je posljedica sve raznovrsnije turističke ponude i kvalitetnog ulaganja u turizam. Time su turizam i hotelijerstvo postali vodeće industrije na svjetskom tržištu sa sve većom potražnjom pa tako i sa samim motivima putovanja. Segment hotelijerstva i sveukupne turističke ponude je zbog toga potrebno učiniti elastičnim i prilagođenim svim zahtjevima suvremenog turista. Dobar primjer daje pansion „Maltar“ koji se već gotovo tri desetljeća neprestano prilagođava potrebama svojih gostiju, uvažavajući i poštujući svaki prijedlog kako bi njihovo poslovanje dovelo do potpunog zadovoljstva gostiju. Osim svoje privlačne lokacije u samom centru grada Varaždina, ovaj pansion pruža autentičan doživljaj i ugodnost samim izgledom, ali i pristupom osoblja što mu daje još jednu posebnost. Uspješno poslovanje dovelo je do početka izgradnje novog hotela istoimenog naziva koji će u narednim godinama zasigurno gradu Varaždinu omogućiti još veći razvoj turizma. U narednim je poglavljima analizirano prvobitno, a zatim postojeće stanje pansiona te je na kraju prikazan sam razvojni projekt koji je doveo do povećanja smještajnih kapaciteta. Ukratko je navedena i ponuda samog grada Varaždina koja privlači turiste iz svih krajeva svijeta. Navedeni su stavovi i mišljenja vlasnika, gospodina Maltara, o samom poslovanju te njegovoj dugogodišnjoj strategiji vođenja ovog, kako ga sam naziva, malog obiteljskog hotela. Provedena anketa dala je rezultate istraživanja o kvaliteti i raznovrsnosti ponude grada Varaždina koja je itekako pokazatelj utjecaja na odluku o odabiru grada Varaždina kao turističke destinacije. Dobiveni rezultati pozitivno su očitovani u svezi kvalitete i ponude grada Varaždina s pokojim segmentima koji bi se s vremenom mogli još više prilagoditi zahtjevima potrošača, ali i samih ponuđača usluga. Na kraju rada prikazan je doprinos izgradnje hotela „Maltar“ gradu Varaždinu i zajednici u smislu povećanja smještajnih kapaciteta, ugleda grada, rasta broja zaposlenih te porasta prihoda od noćenja iz boravišnih pristojbi

Static and vibrational analysis of the GMAW and SMAW joints quality

Structural steel S235JR is one of the main high-strength steels, while the most common welding methods are gas metal arc welding and shielded metal arc welding. Any of weld-strength-related defects can lead to weaker, less ductile welds, cracking and rupture in various steel constructions. Therefore quality of GMAW and SMAW joints were analyzed by using both the destructive tensile strength test and the non-destructive holographic interferometry method. Tensile test results of 10 arc welded specimens and holograms of harmonically excited specimens are presented in this paper. Specifications of specimens and welding parameters are also reviewed along with methodology of the experimental investigation and criteria of the analysis

Caspase-8 and Tyrosine Kinases: A Dangerous Liaison in Cancer

: Caspase-8 is a cysteine-aspartic acid protease that has been identified as an initiator caspase that plays an essential role in the extrinsic apoptotic pathway. Evasion of apoptosis is a hallmark of cancer and Caspase-8 expression is silenced in some tumors, consistent with its central role in apoptosis. However, in the past years, several studies reported an increased expression of Caspase-8 levels in many tumors and consistently identified novel "non-canonical" non-apoptotic functions of Caspase-8 that overall promote cancer progression and sustain therapy resistance. These reports point to the ability of cancer cells to rewire Caspase-8 function in cancer and raise the question of which are the signaling pathways aberrantly activated in cancer that may contribute to the hijack of Caspase-8 activity. In this regard, tyrosine kinases are among the first oncogenes ever identified and genomic, transcriptomic and proteomic studies indeed show that they represent a class of signaling molecules constitutively activated in most of the tumors. Here, we aim to review and discuss the role of Caspase-8 in cancer and its interplay with Src and other tyrosine kinases

Hacia la búsqueda de sentido en la escuela secundaria

Hacia la búsqueda de sentido en la escuela secundari

Insights Into Genetic Landscape of Large Granular Lymphocyte Leukemia

Large granular lymphocyte leukemia (LGLL) is a chronic proliferation of clonal cytotoxic lymphocytes, usually presenting with cytopenias and yet lacking a specific therapy. The disease is heterogeneous, including different subsets of patients distinguished by LGL immunophenotype (CD8+ T\u3b1\u3b2, CD4+ T\u3b1\u3b2, T\u3b3\u3b4, NK) and the clinical course of the disease (indolent/symptomatic/aggressive). Even if the etiology of LGLL remains elusive, evidence is accumulating on the genetic landscape driving and/or sustaining chronic LGL proliferations. The most common gain-of-function mutations identified in LGLL patients are on STAT3 and STAT5b genes, which have been recently recognized as clonal markers and were included in the 2017 WHO classification of the disease. A significant correlation between STAT3 mutations and symptomatic disease has been highlighted. At variance, STAT5b mutations could have a different clinical impact based on the immunophenotype of the mutated clone. In fact, they are regarded as the signature of an aggressive clinical course with a poor prognosis in CD8+ T-LGLL and aggressive NK cell leukemia, while they are devoid of negative prognostic significance in CD4+ T-LGLL and T\u3b3\u3b4 LGLL. Knowing the specific distribution of STAT mutations helps identify the discrete mechanisms sustaining LGL proliferations in the corresponding disease subsets. Some patients equipped with wild type STAT genes are characterized by less frequent mutations in different genes, suggesting that other pathogenetic mechanisms are likely to be involved. In this review, we discuss how the LGLL mutational pattern allows a more precise and detailed tumor stratification, suggesting new parameters for better management of the disease and hopefully paving the way for a targeted clinical approach

A Triphenylphosphonium-Functionalized Delivery System for an ATM Kinase Inhibitor That Ameliorates Doxorubicin Resistance in Breast Carcinoma Mammospheres

Simple Summary Doxorubicin (DOX) is widely used in the treatment of breast cancer. However, resistance limits its effectiveness. In particular, breast cancer stem cells (BCSCs) are associated with DOX resistance. We have previously demonstrated the potential of a polymeric nanocarrier based on a suitably functionalized hyperbranched polyethylenimine that preferentially targets BCSCs. ATM kinase is a key mediator of DNA damage response, so its inhibition has become an attractive therapeutic concept in cancer therapy for the sensitization of cancer cells to chemotherapeutic drugs. Herein, we tested the potential of this drug delivery system that encapsulates an ATM inhibitor to target and sensitize mammospheres-considered as a model system of BCSCs-to an anticancer drug, while having a comparably lower cytotoxic effect against bulk tumor cells. The enzyme ataxia-telangiectasia mutated (ATM) kinase is a pluripotent signaling mediator which activates cellular responses to genotoxic and metabolic stress. It has been shown that ATM enables the growth of mammalian adenocarcinoma stem cells, and therefore the potential benefits in cancer chemotherapy of a number of ATM inhibitors, such as KU-55933 (KU), are currently being investigated. We assayed the effects of utilizing a triphenylphosphonium-functionalized nanocarrier delivery system for KU on breast cancer cells grown either as a monolayer or in three-dimensional mammospheres. We observed that the encapsulated KU was effective against chemotherapy-resistant mammospheres of breast cancer cells, while having comparably lower cytotoxicity against adherent cells grown as monolayers. We also noted that the encapsulated KU sensitized the mammospheres to the anthracycline drug doxorubicin significantly, while having only a weak effect on adherent breast cancer cells. Our results suggest that triphenylphosphonium-functionalized drug delivery systems that contain encapsulated KU, or compounds with a similar impact, are a useful addition to chemotherapeutic treatment schemes that target proliferating cancers

DNA Damage Regulates the Functions of the RNA Binding Protein Sam68 through ATM-Dependent Phosphorylation

Simple Summary Alterations of the complex network of interactions between the DNA damage response pathway and RNA metabolism have been described in several tumors, and increasing efforts are devoted to the elucidation of the molecular mechanisms involved in this network. Previous large-scale proteomic studies identified the RNA binding protein Sam68 as a putative target of the ATM kinase. Herein, we demonstrate that ATM phosphorylates Sam68 upon DNA damage induction, and this post-translational modification regulates both the signaling function of Sam68 in the initial phase of the DNA damage response and its RNA processing activity. Thus, our study uncovers anew crosstalk between ATM and Sam68, which may represent a paradigm for the functional interaction between the DDR pathway and RNA binding proteins, and a possible actionabletarget in human cancers. Cancer cells frequently exhibit dysregulation of the DNA damage response (DDR), genomic instability, and altered RNA metabolism. Recent genome-wide studies have strongly suggested an interaction between the pathways involved in the cellular response to DDR and in the regulation of RNA metabolism, but the molecular mechanism(s) involved in this crosstalk are largely unknown. Herein, we found that activation of the DDR kinase ATM promotes its interaction with Sam68, leading to phosphorylation of this multifunctional RNA binding protein (RBP) on three residues: threonine 61, serine 388 and serine 390. Moreover, we demonstrate that ATM-dependent phosphorylation of threonine 61 promotes the function of Sam68 in the DDR pathway and enhances its RNA processing activity. Importantly, ATM-mediated phosphorylation of Sam68 in prostate cancer cells modulates alternative polyadenylation of transcripts that are targets of Sam68, supporting the notion that the ATM-Sam68 axis exerts a multifaceted role in the response to DNA damage. Thus, our work validates Sam68 as an ATM kinase substrate and uncovers an unexpected bidirectional interplay between ATM and Sam68, which couples the DDR pathway to modulation of RNA metabolism in response to genotoxic stress