Caratterizzazione della risposta all'ipossia in differenti linee cellulari di Neuroblastoma umano

The aim of this research study is to highlight and to compare the behavior of two human neuroblastoma cell lines, representative of two tumor phenotypes, respectively the SHSY5Y less aggressive (not N-MYC amplified), and the IMR-32 more aggressive (N-MYC amplified), after two different hypoxic exposures, that are the first for 4 h or acute hypoxia and the second for 24 h or prolonged hypoxia. The interesting results obtained in this initial study allowed to outline probable scenarios of oxygen deficiency action on neuroblastoma cell cultures. The response of the two neuroblastoma cell cultures to two different hypoxic stimuli showed its greatest differences especially when treatment in hypoxia prolonged over time. The overall view of these first results led to hypothesis that daily hypoxia triggered a series of phenomena that induced SHSY5Y neuroblastoma cells to differentiation towards a neuronal phenotype. These phenomena were precisely the mortality from apoptosis, the cell cycle arrest in G1 phase, the presence of TG2-S involved in differentiation processes, the low presence of metalloproteases involved in tumor invasion and the accumulation of adhesion molecules and in particular ICAM, whose presence seems to be related to neuroblastoma cell differentiation. Instead the IMR-32 cell line, after the same treatment of SHSY5Y cell line, showed good cellular viability and the cell cycle progression. The most interesting result was the unexpected detection of both transglutaminase 2 isoforms in hypoxia, where it was already proven that TG2-L acts to stimulate cell proliferation in contrast to TG2-S. Instead the adhesion molecules ICAM and VCAM and the metalloproteases showed a behavior that must be further verified. These results obtained for the IMR-32 cell line induced the intriguing idea that hypoxia strongly stimulated the proliferation of these neuroblastoma cells, making the tumor even more dangerous and invasive. This first approach to the study of the processes triggered by hypoxia in two different neuroblastoma cell cultures opened interesting horizons on increasingly specific understanding of the behavior of this malignant neoplasm. Furthermore it also offered further insights into the clinic and pediatric surgery on the possibility or the risk of applying techniques such as minimally invasive surgery for biopsies of this tumor, precisely because of the hypoxic environment created by the carbon dioxide insufflation.