G protein-coupled receptors (GPCRs) represent the largest membrane protein family implicated in the therapeutic intervention of a variety of diseases including cancer. Exploration of biological actions of orphan GPCRs may lead to the identification of new targets for drug discovery. This study investigates potential roles of GPR160, an orphan GPCR, in the pathogenesis of prostate cancer. The transcription levels of GPR160 in the prostate cancer tissue samples and cell lines, such as PC-3, LNCaP, DU145 and 22Rv1 cells, were significantly higher than that seen in normal prostate tissue and cells. Knockdown of GPR160 by lentivirus-mediated short hairpin RNA constructs targeting human GPR160 gene (ShGPR160) resulted in prostate cancer cell apoptosis and growth arrest both in vitro and in athymic mice. Differential gene expression patterns in PC-3 cells infected with ShGPR160 or scramble lentivirus showed that 815 genes were activated and 1193 repressed. Functional annotation of differentially expressed genes (DEGs) revealed that microtubule cytoskeleton, cytokine activity, cell cycle phase and mitosis are the most evident functions enriched by the repressed genes, while regulation of programmed cell death, apoptosis and chemotaxis are enriched significantly by the activated genes. Treatment of cells with GPR160-targeting shRNA lentiviruses or duplex siRNA oligos increased the transcription of IL6 and CASP1 gene significantly. Our data suggest that the expression level of endogenous GPR160 is associated with the pathogenesis of prostate cancer.

The serum and glucocorticoid-regulated kinase (SGK) family has been implicated in the regulation of many cellular processes downstream of the PI3K pathway. It plays a crucial role in PI3K-mediated tumorigenesis, making it a potential therapeutic target for cancer. SGK family consists of three isoforms (SGK1, SGK2, and SGK3), which have high sequence homology in the kinase domain and similar substrate specificity with the AKT family. In order to identify novel compounds capable of inhibiting SGK3 activity, a high-throughput screening campaign against 50,400 small molecules was conducted using a fluorescence-based kinase assay that has a Z' factor above 0.5. It identified 15 hits (including nitrogen-containing aromatic, flavone, hydrazone, and naphthalene derivatives) with IC values in the low micromolar to sub-micromolar range. Four compounds with a similar scaffold (i.e., a hydrazone core) were selected for structural modification and 18 derivatives were synthesized. Molecular modeling was then used to investigate the structure-activity relationship (SAR) and potential protein-ligand interactions. As a result, a series of SGK inhibitors that are active against both SGK1 and SGK3 were developed and important functional groups that control their inhibitory activity identified.