AF38469

Neurotensin (NTS), a small neuropeptide, was recently established as a key paracrine mediator of ovulation. NTS mRNA is highly expressed by granulosa cells in response to the luteinizing hormone surge, and multiple NTS receptors are expressed by cells of the ovulatory follicle. To identify the role of NTS receptors NTSR1 and SORT1 in ovulation in vivo, the dominant follicle of cynomolgus macaques (Macaca fascicularis) was injected with either vehicle control, the general NTS receptor antagonist SR142948, the NTSR1-selective antagonist SR48692, or the SORT1-selective antagonist AF38469. hCG was then administered to initiate ovulatory events. Ovulation was successful in all control-injected follicles. Rupture sites were smaller or absent after injection with NTS receptor antagonists. Histological analysis of follicles injected with SR142948, SR48692, or AF38469 revealed increased red blood cell extravasation and pooling in the follicle antrum when compared to controls. NTS receptor antagonist-injected follicles also showed dysregulated capillary formation and reduced luteinization of the granulosa cell layer. Prior in vitro studies showed that NTS significantly increased monkey ovarian microvascular endothelial cell (mOMEC) migration, while decreasing monolayer permeability. The NSTR1 antagonist SR48692 or siRNA knockdown of NTSR1 abrogated the ability of NTS to stimulate mOMEC migration and to decrease monolayer permeability. Similar experiments performed with the SORT1 antagonist AF38469 or siRNA knockdown of SORT1 also resulted in ablation of NTS-mediated changes in migration and permeability after SORT1 signaling was impaired. Together, these data implicate both NTSR1 and SORT1 to be critical mediators of NTS-stimulated ovulation, luteinization, and angiogenesis of the ovulatory follicle.

Glioblastoma (GBM) is a devastating brain cancer with no effective treatment, and there is an urgent need for developing innovative biomarkers as well as therapeutic targets for better management of the disease. The membrane protein sortilin has recently been shown to participate in tumor cell invasiveness in several cancers, but its involvement and clinical relevance in GBM is unclear. In the present study, we explored the expression of sortilin and its potential as a clinical biomarker and therapeutic target for GBM. Sortilin expression was investigated by immunohistochemistry and digital quantification in a series of 71 clinical cases of invasive GBM vs. 20 non-invasive gliomas. Sortilin was overexpressed in GBM and, importantly, higher expression levels were associated with worse patient survival, pointing to sortilin tissue expression as a potential prognostic biomarker for GBM. Sortilin was also detectable in the plasma of GBM patients by enzyme-linked immunosorbent assay (ELISA), but no differences were observed between sortilin levels in the blood of GBM vs. glioma patients. In vitro, sortilin was detected in 11 brain-cancer-patient-derived cell lines at the anticipated molecular weight of 100 kDa. Interestingly, targeting sortilin with the orally bioavailable small molecule inhibitor AF38469 resulted in decreased GBM invasiveness, but cancer cell proliferation was not affected, showing that sortilin is targetable in GBM. Together, these data suggest the clinical relevance for sortilin in GBM and support further investigation of GBM as a clinical biomarker and therapeutic target.