3 research outputs found
c-myb down regulation is associated with apoptosis in human neuroblastoma cells.
The c-myb transcriptional regulator plays a crucial role in the control of several proliferative/differentiative processes in haematopoietic cells. Its expression and function is not lineage-restricted, since c-myb is also expressed in solid tumours such as neuroblastomas, where its transcription is decreased by retinoic acid. In response to retinoic acid, neuroblastomas differentiate either towards a neuronal phenotype or undergo apoptosis. The temporal relationship between reduction in c-myb mRNA levels and the differentiative/proliferative/apoptotic processes suggests that c-myb may play a key role in the control of growth of these neuroectodermal tumours. Transfection of neuroblastoma cells with expression vectors containing segments of human c-myb cDNA in antisense orientation yielded fewer transfectant clones, with a far slower proliferation rate, than transfection with the corresponding sense construct. The dramatic growth arrest and reduction in cell number in the antisense transfectants is due to the induction of apoptosis. Apoptosis in the c-myb antisense-transfected cells is further increased in reduced serum conditions
Coexpression of messenger RNA for TRK protooncogene and low affinity nerve growth factor receptor in neuroblastoma with favorable prognosis.
Abstract: Nerve growth factor (NGF), essential for differentiation and survival of sympathetic neurons is suggested to play a role in differentiation or regression of neuroblastoma. Expression of mRNA for the trk protooncogene, encoding a tyrosine kinase receptor essential for functional NGF signal transduction, and mRNA for the low affinity NGF receptor (LNGFR) was examined in 45 neuroblastomas and 3 benign ganglioneuromas using Northern blot analysis. Expression of trk mRNA and LNGFR mRNA correlated with young age, favorable clinical stages, and absence of N-myc amplification. All children (n = 19) with neuroblastomas coexpressing mRNA for trk and LNGFR are alive 8-84 months from diagnosis, regardless of age and stage. In contrast, no child (n = 15) with tumor lacking trk mRNA is alive without disease. Three subsets of patients were distinguished, one favorable (trk+, LNGFR+, n = 19, 100% survival probability), one intermediate (trk+, LNGFR-, n = 11, 62.3% survival probability), and one unfavorable (trk-, LNGFR +/-, n = 15, 0% survival probability, P < 0.001). In widespread neuroblastoma stage IVS prone to spontaneous regression, three tumors coexpressing trk and LNGFR mRNAs regressed after no or minimal therapy while the remaining tumor expressing trk but not LNGFR mRNA progressed to a fatal outcome. It is concluded that neuroblastomas coexpressing mRNA for both NGF receptor subtypes are favorable tumors likely to differentiate or regress spontaneously or respond to conventional therapy. It is further hypothesized that loss of functional NGF receptors is an important step in tumorigenesis of undifferentiated malignant childhood neuroblastoma. For these unfavorable tumors current therapy remains futile and first-line innovative therapy is justified
Game theoretic optimal user association in emergency networks
The availability of effective communications in post-disaster scenarios is key to implement emergency networks that enable the sharing of critical information and support the coordination of the emergency response. To deliver those levels of QoS suitable to these applications, it is vital to exploit the multiple communication opportunities made available by the progressive deployment of the 5G and Smart City paradigms, ranging from ad-hoc networks among smartphones and surviving IoT devices, to cellular networks but also drone-based and vehicle-based wireless access networks. Therefore, the user device should be able to opportunistically select the most convenient among them to satisfy the demands for QoS imposed by the applications and also minimize the power consumption. The driving idea of this paper is to leverage non-cooperative game theory to design such an opportunistic user association strategy in a post-disaster scenario using UAV ad-hoc networks. The adaptive game-theoretic scheme allows increasing of the QoS of the communication means by lowering the loss rate and also keeps moderate the energy consumption