Glioblastoma Multiforme (GBM) is a debilitating type of brain cancer with a high mortality rate. Despite current treatment options such as surgery, radiotherapy, and the use of temozolomide and bevacizumab, it is considered incurable. Various methods, such as drug repositioning, have been used to increase the number of available treatments. Drug repositioning is the use of FDA-approved drugs to treat other diseases. This is possible because the drugs used for this purpose have polypharmacological effects. This means that these medications can bind to multiple targets, resulting in multiple mechanisms of action. Antipsychotics are one type of drug used to treat GBM. Antipsychotics are a broad class of drugs that can be further subdivided into typical and atypical classes. Typical antipsychotics include chlorpromazine, trifluoperazine, and pimozide. This class of antipsychotics was developed early on and primarily works on dopamine D2 receptors, though it can also work on others. Olanzapine and Quetiapine are examples of atypical antipsychotics, a category that was created later. These medications have a high affinity for serotonin receptors such as 5- HT2, but they can also act on dopamine and H1 receptors. Antipsychotic medications, in the case of GBM, also have other effects that can affect multiple pathways due to their polypharmacological effects. These include NF-B suppression, cyclin deregulation, and -catenin phosphorylation, among others. This review will delve deeper into the polypharmacological, the multiple effects of antipsychotics in the treatment of GBM, and an outlook for the field's future progression.
Neurons synthesizing gonadotropin-inhibitory hormone (GnIH) have been implicated in the control of reproduction, food intake and stress. Serotonin (5-HT) receptors have been shown in GnIH neurons; however, their functional role in the regulation of GnIH neurons remains to be elucidated. In this study, we measured intracellular calcium ion levels following 5-HT treatment to hypothalamic primary cultures of enhanced fluorescent green protein-tagged GnIH (EGFP-GnIH) neurons from Wistar rat pups of mixed sex. Three days after initial seeding of the primary cultures, the test groups were pre-treated with lithium chloride to selectively inhibit glycogen synthase kinase 3 beta to promote intracellular calcium levels, whereas the control groups received culture medium with no lithium chloride treatment. 24 h later, the cultures were incubated with rhodamine-2AM (rhod-2AM) calcium indicator dye for one hour prior to imaging. 5-HT was added to the culture dishes 5 min after commencement of imaging. Analysis of intracellular calcium levels in EGFP-GnIH neurons showed that pre-treatment with lithium chloride before 5-HT treatment resulted in significant increase in intracellular calcium levels, two times higher than the baseline. This suggests that lithium chloride enhances the responsiveness of GnIH neurons to 5-HT.
Postnatal treatment with selective serotonin reuptake inhibitors (SSRIs) has been found to affect brain development and the regulation of reproduction in rodent models. The normal masculinization process in the brain requires a transient decrease in serotonin (5-HT) levels in the brain during the second postnatal week. Strict regulation of androgen receptor (AR) and gonadotropin-releasing hormone (GnRH) expression is important to control male reproductive activity. Therefore, this study was designed to examine the effects of a potent SSRI (citalopram) on male sexual behavior and expression levels of AR and GnRH in adult male mice receiving either vehicle or citalopram (10mg/kg) daily during postnatal days 8-21. The citalopram-treated male mice showed altered sexual behavior, specifically a significant reduction in the number of intromissions preceding ejaculation compared with the vehicle-treated mice. The citalopram-treated male mice displayed elevated anxiety-like behavior in an open field test and lower locomotor activity in their home cage during the subjective night. Although there was no change in GnRH and AR mRNA levels in the preoptic area (POA), quantified by real-time polymerase chain reaction, immunostained AR cell numbers in the medial POA were decreased in the citalopram-treated male mice. These results suggest that the early-life inhibition of 5-HT transporters alters the regulation of AR expression in the medial POA, likely causing decreased sexual behavior and altered home cage activity in the subjective night.