TACR2 is associated with the immune microenvironment and inhibits migration and proliferation via the Wnt/β-catenin signaling pathway in prostate cancer

Background The tachykinin receptor 2 (TACR2) is encoded by the tachykinin receptor correlation gene. Recent microarray analysis for prostate cancer suggests that TACR2 expression is associated with clinical phenotype and disease-free survival among patients with prostate cancer. Results TACR2 protein levels were lower in prostate cancer tissues than in adjacent normal prostate tissue. TACR2 expression significantly correlated with clinical stage, Gleason scores, and survival outcomes. TACR2 expression positively correlated with mast cells and negatively correlated with M2 macrophages. Overexpression of TACR2 promoted the migration and proliferation of prostate cancer cells by regulating the Wnt signaling pathway. Conclusions The TACR2-Wnt/β-catenin signaling pathway is critical in prostate cancer. TACR2 may affect tumor cells’ occurrence and development by changing the content of immune cells in the tumor microenvironment. These findings suggest that TACR2 may be a candidate molecular biomarker for prostate cancer therapy.

Crystal structure of the human NK1 tachykinin receptor

The NK1 tachykinin G-protein–coupled receptor (GPCR) binds substance P, the first neuropeptide to be discovered in mammals. Through activation of NK1R, substance P modulates a wide variety of physiological and disease processes including nociception, inflammation, and depression. Human NK1R (hNK1R) modulators have shown promise in clinical trials for migraine, depression, and emesis. However, the only currently approved drugs targeting hNK1R are inhibitors for chemotherapy-induced nausea and vomiting (CINV). To better understand the molecular basis of ligand recognition and selectivity, we solved the crystal structure of hNK1R bound to the inhibitor L760735, a close analog of the drug aprepitant. Our crystal structure reveals the basis for antagonist interaction in the deep and narrow orthosteric pocket of the receptor. We used our structure as a template for computational docking and molecular-dynamics simulations to dissect the energetic importance of binding pocket interactions and model the binding of aprepitant. The structure of hNK1R is a valuable tool in the further development of tachykinin receptor modulators for multiple clinical applications.

Characterisation, localisation and expression of porcine TACR1, TACR2 and TACR3 genes

Substance P is involved in many physiological and pathophysiological processes. This functional diversity is mediated by three neurokinin receptor subtypes (NK1R, NK2R and NK3R) encoded by the TACR1, TACR2 and TACR3 genes, respectively. Despite the increasing interest in using pigs (Sus scrofa) to study human disease mechanisms, the sequences of these receptors are still unconfirmed or in the case of the NK1 receptor, not yet even unpredicted. We employed in silico analysis to define the localisation of the porcine tachykinin receptor genes, and to predict the structures and amino acid sequences of the respective proteins. A reverse transcription polymerase chain reaction (RT-PCR) assay was performed to analyse the expression of tachykinin receptor genes in different porcine tissues. The data show that the TACR1 gene is located on chromosome 3, TACR2 on chromosome 14 and TACR3 on chromosome 8. All three genes encode proteins with structures that incorporate features of G-protein-coupled receptors with sizes of 407, 381 and 464 amino acids, respectively. The receptors display a high degree of similarity to other mammalian neurokinin receptors. The NK1R subtype is expressed in both the central nervous system and peripheral tissues, while NK2R expression seems to be localised mostly to peripheral tissues. The expression of NK3R is found mainly in the central nervous system. This report provides for the first time the results of a comprehensive analysis of the structure and distribution of porcine NK1R, as well as other porcine neurokinin receptors and their genes. We hope that our data may offer an invaluable foundation for the future studies on the function of diverse tachykinin peptides in the central nervous system and peripheral tissues.