Massimo Squatrito

the effects they observed could be influenced by inhibition of other types of Trk receptors or signaling molecules downstream of Trk. We have recently started a series of experiments aiming to verify whether specific TrkB inhibition reduces glioma cell proliferation using ANA-12, a small-molecule selective TrkB antagonist. Our first results showed that ANA-12 effectively and dose-dependently reduces the viability of a human glioblastoma cell line with almost complete disappearance of cultured cells 72 hours after treatment (Fig. Therefore, selective TrkB inhibition might prove to be an effective experimental therapeutic strategy, possibly with fewer off-target toxicities compared with multitarget drugs in patients with astrocytomas harboring oncogenic TrkB.

The miR-17 approximately 92 cluster is frequently amplified or overexpressed in human cancers and has emerged as the prototypical oncogenic polycistron microRNA (miRNA). miR-17 approximately 92 is a direct transcriptional target of c-Myc, and experiments in a mouse model of B-cell lymphomas have shown cooperation between these two oncogenes. However, both the molecular mechanism underlying this cooperation and the individual miRNAs that are responsible for it are unknown. By using a conditional knockout allele of miR-17 approximately 92, we show here that sustained expression of endogenous miR-17 approximately 92 is required to suppress apoptosis in Myc-driven B-cell lymphomas. Furthermore, we show that among the six miRNAs that are encoded by miR-17 approximately 92, miR-19a and miR-19b are absolutely required and largely sufficient to recapitulate the oncogenic properties of the entire cluster. Finally, by combining computational target prediction, gene expression profiling, and an in vitro screening strategy, we identify a subset of miR-19 targets that mediate its prosurvival activity.