beta-ionone and Prostatic-Neoplasms

β-ionone is a terminal cyclic analog of beta-carotenoids widely found in plants. In recent years, accumulating evidence has shown that β-ionone exerts antitumor effects on various malignant tumors. However, limited studies have revealed the role of β-ionone in regulating the epithelial-mesenchymal transition (EMT) of prostate cancer (PCa) cells. This study aimed to investigate the effect of β-ionone on the EMT process of PCa, focusing on Wnt/β-catenin signaling pathway.. After exposure to β-ionone, cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the Brdu proliferation assay. The Transwell and wounding healing were used to investigate the migration and invasion abilities of PCa cells. Expression of proteins involved in the EMT process (E-cadherin, N-cadherin, vimentin) and proteins in the Wnt/β-catenin pathway (β-catenin, GSK3-β, and p-GSK3-β) were explored by western blotting. The effects of β-ionone on β-catenin degradation were explored by cycloheximide tracking assay and. The migration, invasion, and EMT process of PCa Human PC-3 prostate adenocarcinoma cells (PC3) and Human 22RV1 prostate adenocarcinoma cells (22RV1) cells were significantly inhibited after β-ionone treatment. In addition, β-ionone also inhibited the growth and EMT process of subcutaneous xenograft tumors in nude mice. The study also found that β-catenin, which promotes EMT, was downregulated after β-ionone treatment. Further mechanistic studies revealed that β-ionone inhibited the Wnt/β-catenin pathway by accelerating the ubiquitination and degradation of β-catenin in PCa, thus inhibiting the downstream migration, invasion, and EMT processes.. These findings demonstrate that β-ionone may be a potential natural compound targeting the Wnt/β-catenin pathway for the treatment of PCa.

Topics: Adenocarcinoma; Animals; beta Catenin; Cell Line, Tumor; Cell Movement; Cell Proliferation; Epithelial-Mesenchymal Transition; Glycogen Synthase Kinase 3; Humans; Male; Mice; Mice, Nude; Prostate; Prostatic Neoplasms; Wnt Signaling Pathway

The prostate-specific G protein-coupled receptor (PSGR) is a class A G protein-coupled receptor (GPCR) that is specifically expressed in prostate epithelial cells, and its expression has been linked to prostate cancer (PCa) progression. Here, we show that activation of PSGR with its ligand β-ionone, an end-ring analog of β-carotenoid, can suppress PCa cell growth both in vitro and in vivo model. Dissection of the mechanism underlying this relationship reveals that activation of PSGR by β-ionone suppresses AR nuclear translocation via phosphorylation of AR at residue Ser650 by p38 and JNK, which leads to the suppression of AR transactivation, further suppressing PCa cell growth. Overall, we link a cancer cell-specific GPCR with the nuclear AR and show that targeting PSGR can provide us a new target to combat PCa better.

Topics: Animals; Cell Line, Tumor; Cell Nucleus; Disease Progression; Humans; Male; MAP Kinase Kinase 4; Mice; Mice, Nude; Neoplasm Proteins; Norisoprenoids; p38 Mitogen-Activated Protein Kinases; PC-3 Cells; Phosphorylation; Prostatic Neoplasms; Receptors, Androgen; Receptors, Odorant; Xenograft Model Antitumor Assays

We previously reported that the olfactory receptor OR51E2, overexpressed in LNCaP prostate cancer cells, promotes cell invasiveness upon stimulation of its agonist β-ionone, and this phenomenon increases metastatic spread. Furthermore, we showed that the induced cell invasiveness involves a PI3 kinase dependent signalling pathway. We report here the results of a new investigation to address whether gallein, a small inhibitor of G protein βγ subunit interaction with PI3 kinase, can inhibit β-ionone effects both in vitro and in vivo.. We demonstrate that gallein can inhibit the β-ionone-induced cell invasiveness in vitro, as well as the spread of metastases in vivo. LNCaP cell invasiveness, assessed using spheroid cultures in collagen gels in vitro, was increased by β-ionone and the effect was reversed by co-administration of gallein. LNCaP tumour cells, subcutaneously inoculated to immunodeficient mice, generated more metastases in vivo when β-ionone was applied through the skin. Furthermore, the intraperitoneal injection of gallein inhibited this increased metastasis spread. Our results thus support the role of OR51E2 in the β-ionone observed effects, and suggest that gallein could be a potential new agent in personalized medicine of the tumours expressing OR51E2.

Topics: Animals; Cell Line, Tumor; GTP-Binding Protein beta Subunits; GTP-Binding Protein gamma Subunits; Humans; Male; Mice; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Proteins; Norisoprenoids; Prostatic Neoplasms; Receptors, Odorant; Signal Transduction; Tumor Cells, Cultured; Xanthenes

Olfactory receptors are G protein-coupled receptors. Some of them are expressed in tumor cells, such as the OR51E2 receptor overexpressed in LNCaP prostate cancer cells. It is considered a prostate tumor marker. We previously demonstrated that this receptor is able to promote LNCaP cell invasiveness in vitro upon stimulation with its odorant agonist β-ionone, leading to increased generation of metastases in vivo. In the present study, we show that even a relatively short exposure to β-ionone is sufficient to promote metastasis emergence. Moreover, α-ionone, considered an OR51E2 antagonist, in fact promotes prostate tumor growth in vivo. The combination of α-ionone with β-ionone triggers a higher increase in the total tumor burden than each molecule alone. To support the in vivo results, we demonstrate in vitro that α-ionone is a real agonist of OR51E2, mainly sustaining LNCaP cell growth, while β-ionone mainly promotes cell invasiveness. So, while structurally close, α-ionone and β-ionone appear to induce different cellular effects, both leading to increased tumor aggressiveness. This behaviour could be explained by a different coupling to downstream effectors, as it has been reported for the so-called biased ligands of other G protein-coupled receptors.

Topics: Animals; Cell Line, Tumor; Cell Movement; Disease Progression; Humans; Male; Mice; Neoplasm Metastasis; Neoplasm Proteins; Neoplasm Transplantation; Norisoprenoids; Prostatic Neoplasms; Receptors, Odorant; Up-Regulation

The prostate-specific G-protein-coupled receptor 1 (PSGR1) is an olfactory receptor specifically expressed in the prostate gland. PSGR1 expression is elevated both in benign prostatic hyperplasia tissue and in prostate cancer. Stimulation of PSGR1 by the odorant β-ionone leads to an increase in the intracellular Ca(2+) concentration, activation of mitogen-activated protein (MAP) kinases and a decrease in prostate cancer cell proliferation. To further extend our knowledge about PSGR1 signaling in prostate cancer cells, we performed a quantitative phosphoproteomics study using stable isotope labeling by amino acids in cell culture and mass spectrometry. We report 51 differentially regulated phosphorylation sites in 24 proteins with functions in cytoskeletal remodeling, signaling and ion transport. Activation of PSGR1 evoked an increase in intracellular pH mediated by the sodium/hydrogen exchanger NHE1. Furthermore, we report the protein tyrosine kinase Pyk2 as a central effector of PSGR1 signaling cascades in LNCaP cells. Our data show that phosphorylation of p38 MAP kinase is triggered by Pyk2. In addition, we confirmed dephosphorylation of the tumor suppressor protein N-myc downstream regulated gene 1 (NDRG1) at Ser330 downstream of Pyk2. Since NDRG1 impacts oncogenic signaling pathways interfering with tumor progression, we suggest that the Pyk2-NDRG1 axis is possibly involved in conveying the anti-proliferative effect of β-ionone in prostate cancer cells. This article is part of a Special Issue entitled: Medical Proteomics.

Topics: Cell Cycle Proteins; Cell Line, Tumor; Focal Adhesion Kinase 2; Humans; Intracellular Signaling Peptides and Proteins; Male; MAP Kinase Signaling System; Neoplasm Proteins; Norisoprenoids; p38 Mitogen-Activated Protein Kinases; Phosphoproteins; Phosphorylation; Prostatic Neoplasms; Receptors, Odorant

Olfactory receptors (ORs) are expressed in the olfactory epithelium, where they detect odorants, but also in other tissues with additional functions. Some ORs are even overexpressed in tumor cells. In this study, we identified ORs expressed in enterochromaffin tumor cells by RT-PCR, showing that single cells can co-express several ORs. Some of the receptors identified were already reported in other tumors, but they are orphan (without known ligand), as it is the case for most of the hundreds of human ORs. Thus, genes coding for human ORs with known ligands were transfected into these cells, expressing functional heterologous ORs. The in vitro stimulation of these cells by the corresponding OR odorant agonists promoted cell invasion of collagen gels. Using LNCaP prostate cancer cells, the stimulation of the PSGR (Prostate Specific G protein-coupled Receptor), an endogenously overexpressed OR, by β-ionone, its odorant agonist, resulted in the same phenotypic change. We also showed the involvement of a PI3 kinase γ dependent signaling pathway in this promotion of tumor cell invasiveness triggered by OR stimulation. Finally, after subcutaneous inoculation of LNCaP cells into NSG immunodeficient mice, the in vivo stimulation of these cells by the PSGR agonist β-ionone significantly enhanced metastasis emergence and spreading.

Topics: Animals; Calcium; Cell Line, Tumor; Collagen; Enterochromaffin Cells; Gels; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Mice, SCID; Neoplasm Invasiveness; Neoplasm Proteins; Neoplasm Transplantation; Norisoprenoids; Olfactory Receptor Neurons; Phosphatidylinositol 3-Kinases; Prostatic Neoplasms; Protein Subunits; Receptors, Odorant; Signal Transduction

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase is the rate-limiting activity in the mevalonate pathway that provides essential intermediates for posttranslational modification of growth-associated proteins. Assorted dietary isoprenoids found in plant foods suppress HMG CoA reductase and have cancer chemopreventive activity. β-Ionone, a cyclic sesquiterpene and an end-ring analog of β-carotene, induced concentration-dependent inhibition of the proliferation of human DU145 (IC50 = 210 μmol/L) and LNCaP (IC50 = 130 μmol/L) prostate carcinoma cells and PC-3 prostate adenocarcinoma cells (IC50 = 130 μmol/L). Concomitantly, β-ionone-induced apoptosis and cell cycle arrest at the G1 phase in DU145 and PC-3 cells were shown by fluorescence microscopy, flow cytometry, and TUNEL reaction, and downregulation of cyclin-dependent kinase 4 (Cdk4) and cyclin D1 proteins. Growth suppression was accompanied by β-ionone-induced downregulation of reductase protein. A blend of β-ionone (150 μmol/L) and trans, trans-farnesol (25 μmol/L), an acyclic sesquiterpene that putatively initiates the degradation of reductase, suppressed the net growth of DU145 cells by 73%, an impact exceeding the sum of those of β-ionone (36%) and farnesol (22%), suggesting a synergistic effect. β-ionone, individually or in combination with other HMG CoA reductase suppressors, may have potential in prostate cancer chemoprevention and/or therapy.

Topics: Adenocarcinoma; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma; Cell Cycle Checkpoints; Cell Line, Tumor; Dose-Response Relationship, Drug; Farnesol; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inhibitory Concentration 50; Male; Norisoprenoids; Prostatic Neoplasms

Olfactory receptors (ORs) are expressed not only in the sensory neurons of the olfactory epithelium, where they detect volatile substances, but also in various other tissues where their potential functions are largely unknown. Here, we report the physiological characterization of human OR51E2, also named prostate-specific G-protein-coupled receptor (PSGR) due to its reported up-regulation in prostate cancer. We identified androstenone derivatives as ligands for the recombinant receptor. PSGR can also be activated with the odorant beta-ionone. Activation of the endogenous receptor in prostate cancer cells by the identified ligands evoked an intracellular Ca2+ increase. Exposure to beta-ionone resulted in the activation of members of the MAPK family and inhibition of cell proliferation. Our data give support to the hypothesis that because PSGR signaling could reduce growth of prostate cancer cells, specific receptor ligands might therefore be potential candidates for prostate cancer treatment.

Topics: Androsterone; Calcium; Cell Division; Cell Line, Tumor; Humans; JNK Mitogen-Activated Protein Kinases; Kidney; Ligands; Male; Neoplasm Proteins; Norisoprenoids; Olfactory Mucosa; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Prostate; Prostatic Neoplasms; Receptors, Odorant; Recombinant Proteins; Signal Transduction