The high mortality in patients affected by glioblastoma (GBM) is primarily caused by extensive infiltration ability into surrounding normal brain leading to an inevitable occurrence of relapse. The mesenchymal transition is one of the most aggressive modalities used by GBM cells to invade the normal tissue by interacting with different microenvironment components and exploiting various factors including cytokines and chemokines produced by both tumor cells and cell component of the tumor microenviroment. Our study is based on an observation derived from a group of 24 GBM patients enrolled in a clinical study active at Istituto Neurologico Besta and treated with dendritic cells loade with autologous tumor lysate. A total of seven patients underwent a second surgery after the occurrence of the relapse. A first evaluation performed on tumor specimens from first and second surgery revealed a chemokine signature potentially involved in the tumor evolution and recruitment of myeloid derived suppressor cells (MDSCs), one of the most important immunesuppressive components of GBM microenvironment. Two relapses from two patients who did not respond to the dendritic cell treatment, showed a mesenchymal transition with an evident evolution from GBM to gliosarcoma, as defined by morphological analysis. First, we have observed a significant increased expression of CXCL5, CXCL7 and CXCR2 in these two relapses compared to first surgery specimens. Notably a high expression of CXCL5, already identified as relevant in the mesenchymal subtype, correlated with a poor progression free survival of this subgroup of patients, supporting the relevance of the tumor microenvironment in GBM progression. We also found that the CXCL5/CXCL7/CXCR2 axis activated in GBM microenvironment was associated to a significant increased level of S100A8/9 and increased arginase (ARG-1) activity assessed in serum. The ARG-1 expression was also found significantly up-regulated in GBM relapses of patients showing high enzyme activity in serum. Finally, by flow cytometry analysis we have investigated the frequency of MDSCs infiltrating a relapse of one of the patients showing the mesenchymal transition. We found a robust infiltration of CD33+CD15+CD14- cells corresponding to neutrophilic MDSCs. Our findings support that specific chemokines produced at the tumor site are responsible for MDSCs recruitment and that MDSCs as important immunesuppressive component of the tumor microenvironment can drive tumor progression including the mesenchymal transition.
L'elevata mortalità nei pazienti affetti da glioblastoma multiforme (GBM) è causata principalmente dall’estesa capacità di infiltrazione nel tessuto sano che porta a una inevitabile insorgenza di una recidiva. Una delle forme più aggressive di infiltrazione del GBM è rappresentata dalla transizione o differenziamento mesenchimale con cui le cellule di GBM invadono il tessuto circostante interagendo con varie componenti del microambiente e sfruttando una serie di fattori tra cui citochine e chemochine prodotte sia dal tumore sia dalle componenti cellulari del microambiente. Il nostro studio si basa su un’osservazione derivata da gruppo di 24 pazienti affetti da glioblastoma primario arruolati in un protocollo clinico attivo presso l’Istituto Neurologico Besta che prevedere il trattamento con immunoterapia con cellule dendritiche caricate con lisato tumorale autologo. Un totale di sette pazienti, di cui due definiti responder, in seguito alla comparsa di recidiva, ha subito un secondo intervento chirurgico. Una prima valutazione condotta su tumore primario e recidiva ha permesso di definire una signature di chemochine potenzialmente coinvolte nell’evoluzione del tumore e nel reclutamento delle cellule mieloidi soppressive (MSDCs), considerate una importante componente immunosoppressiva del microambiente del GBM. Inoltre in due dei sette pazienti, che non hanno risposto al trattamento di immunoterapia, l’evoluzione del tumore ha subito un differenziamento di tipo mesenchimale, mostrando una evoluzione da glioblastoma a gliosarcoma valutata mediante studi morfologici. Inizialmente abbiamo dimostrato un elevato e significativo aumento dell’espressione di CXCL5, CXCL7 e il loro recettore CXCR2 in queste due recidive rispetto al primo intervento. Di particolare rilevanza è risultata CXCL5, già nota come associata al sottotipo molecolare di tipo mesenchimale, la cui elevata espressione correla significativamente con una peggiore sopravvivenza libera da malattia del nostro sottogruppo di pazienti, supportando la rilevanza del microambiente nella progressione del GBM. Abbiamo inoltre trovato che l’attivazione dell’asse CXCL5/CXCL7/CXCR2 nel microambiente tumorale nei pazienti non responder è correlato con un incrementato del livello di S100A8/9 e una aumentata attività dell’arginasi (ARG-1) misurati nel siero. A livello tumorale l’espressione di ARG-1 è stata trovata significativamente più espressa nei pazienti con elevata attività dello stesso enzima nel siero. Inoltre l’analisi citometrica condotta sulla recidiva di uno dei GBM che ha subito transizione mesenchimale ha permesso di rilevare una elevata infiltrazione di cellule CD33+CD15+CD14- riconducibili a MDSCs neutrofiliche. In generale i nostri risultati ci suggeriscono che le chemochine prodotte nel sito del tumore sono responsabili del reclutamento di MDSCs e che queste cellule che determinano un microambiente immunosoppressivo ne guidano la differenziazione mesenchimale.
L’espressione intratumorale di chemochine correlate a cellule mieloidi soppressive guida la transizione mesenchimale e l’insorgenza di recidiva del glioblastoma
RIBECCO, VALENTINO
2015/2016
Abstract
The high mortality in patients affected by glioblastoma (GBM) is primarily caused by extensive infiltration ability into surrounding normal brain leading to an inevitable occurrence of relapse. The mesenchymal transition is one of the most aggressive modalities used by GBM cells to invade the normal tissue by interacting with different microenvironment components and exploiting various factors including cytokines and chemokines produced by both tumor cells and cell component of the tumor microenviroment. Our study is based on an observation derived from a group of 24 GBM patients enrolled in a clinical study active at Istituto Neurologico Besta and treated with dendritic cells loade with autologous tumor lysate. A total of seven patients underwent a second surgery after the occurrence of the relapse. A first evaluation performed on tumor specimens from first and second surgery revealed a chemokine signature potentially involved in the tumor evolution and recruitment of myeloid derived suppressor cells (MDSCs), one of the most important immunesuppressive components of GBM microenvironment. Two relapses from two patients who did not respond to the dendritic cell treatment, showed a mesenchymal transition with an evident evolution from GBM to gliosarcoma, as defined by morphological analysis. First, we have observed a significant increased expression of CXCL5, CXCL7 and CXCR2 in these two relapses compared to first surgery specimens. Notably a high expression of CXCL5, already identified as relevant in the mesenchymal subtype, correlated with a poor progression free survival of this subgroup of patients, supporting the relevance of the tumor microenvironment in GBM progression. We also found that the CXCL5/CXCL7/CXCR2 axis activated in GBM microenvironment was associated to a significant increased level of S100A8/9 and increased arginase (ARG-1) activity assessed in serum. The ARG-1 expression was also found significantly up-regulated in GBM relapses of patients showing high enzyme activity in serum. Finally, by flow cytometry analysis we have investigated the frequency of MDSCs infiltrating a relapse of one of the patients showing the mesenchymal transition. We found a robust infiltration of CD33+CD15+CD14- cells corresponding to neutrophilic MDSCs. Our findings support that specific chemokines produced at the tumor site are responsible for MDSCs recruitment and that MDSCs as important immunesuppressive component of the tumor microenvironment can drive tumor progression including the mesenchymal transition.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/24932