orlistat and Prostatic-Neoplasms

Androgen deprivation therapy (ADT) is one of the typical treatments used for patients with prostate cancer (PCa). ADT, however, may fail when PCa develops castration-resistance. Fatty acid synthase (FASN), a critical enzyme involved in fatty acid synthesis, is found to be up-regulated in PCa. Since enzalutamide and ADT are frequently used for the treatment of PCa, the present study aimed to unravel the underlying mechanism of combination of orlistat, an FASN inhibitor, and enzalutamide using PC3 cell line; and orlistat and castration in PC3 tumor-bearing animal model. Cytotoxicity was determined by AlamarBlue assay. Drug effects on the cell cycle and protein expressions were assayed by the flow cytometry and Western blot. Electromobility shift assay was used to evaluate the NF-κB activity. The tumor growth delay, expressions of the signaling-related proteins, and histopathology post treatments of orlistat and castration were evaluated in PC3 tumor-bearing mouse model. The results showed that orlistat arrested the PC3 cells at the G1 phase of the cell cycle and enhanced the cytotoxic effects of enzalutamide synergistically. Pretreatment with orlistat combined with castration inhibited the tumor growth significantly compared with those of castration and orlistat treatments alone in PC3 tumor-bearing mice. Combination treatment reduced both FASN and NF-κB activities and their downstream effector proteins. The present study demonstrated the synergistic effects of orlistat combined with enzalutamide in vitro and castration in vivo on human PCa.

Topics: Animals; Antineoplastic Agents; Benzamides; Cell Cycle; Enzyme Inhibitors; Fatty Acid Synthase, Type I; Humans; Male; Mice; Mice, Nude; NF-kappa B; Nitriles; Orchiectomy; Orlistat; PC-3 Cells; Phenylthiohydantoin; Prostatic Neoplasms

Elevated fatty acid synthase (FASN) has been reported in both androgen-dependent and -independent prostate cancers. Conventional treatment for prostate cancer is radiotherapy (RT); however, the following radiation-induced radioresistance often causes treatment failure. Upstream proteins of FASN such as Akt and NF-κB are found increased in the radioresistant prostate cancer cells. Nevertheless, whether inhibition of FASN could improve RT outcomes and reverse radiosensitivity of prostate cancer cells is still unknown. Here, we hypothesised that orlistat, a FASN inhibitor, could improve RT outcomes in prostate cancer. Orlistat treatment significantly reduced the S phase population in both androgen-dependent and -independent prostate cancer cells. Combination of orlistat and RT significantly decreased NF-κB activity and related downstream proteins in both prostate cancer cells. Combination effect of orlistat and RT was further investigated in both LNCaP and PC3 tumour-bearing mice. Combination treatment showed the best tumour inhibition compared to that of orlistat alone or RT alone. These results suggest that prostate cancer treated by conventional RT could be improved by orlistat via inhibition of FASN.

Topics: Animals; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Fatty Acid Synthase, Type I; Fatty Acid Synthesis Inhibitors; Humans; Male; Mice; Mice, Nude; NF-kappa B; Orlistat; PC-3 Cells; Prostate; Prostatic Neoplasms; Radiation-Sensitizing Agents

The naturally occurring pentacyclic diterpenoid gibberellic acid (1) was used in the generation of a drug-like amide library using parallel-solution-phase synthesis. Prior to the synthesis, a virtual library was generated and prioritized based on drug-like physicochemical parameters such as log P, hydrogen bond donor/acceptor counts, and molecular weight. The structures of the synthesized analogues (2-13) were elucidated following analysis of the NMR, MS, UV, and IR data. Compound 12 afforded crystalline material, and its structure was confirmed by X-ray crystallographic analysis. All compounds were evaluated in vitro for cytotoxicity and deregulation of lipid metabolism in LNCaP prostate cancer cells. While no cytotoxic activity was identified at the concentrations tested, synthesized analogues 3, 5, 7, 10, and 11 substantially reduced cellular uptake of free cholesterol in prostate cancer cells, suggesting a novel role of gibberellic acid derivatives in deregulating cholesterol metabolism.

Topics: Biological Products; Cell Line, Tumor; Cholesterol; Crystallography, X-Ray; Cytotoxins; Gibberellins; Humans; Lipid Metabolism; Magnetic Resonance Spectroscopy; Male; Prostatic Neoplasms

Prostate cancer (PCa) is one of the leading causes of cancer-related deaths in men worldwide. Fatty acid synthase (FASN) is reported to be overexpressed in several cancers including PCa, and this has led to clinical cancer treatments that utilize various FASN inhibitors such as the anti-obesity drug, Orlistat. However, pharmacological limitations have impeded the progress in cancer treatments expected thus far with FASN inhibition. In this study, we investigated a novel therapeutic combination to enhance the toxic potential of Orlistat in three different PCa cell-lines (DU145, PC3, and LNCaP). We show that Orlistat and 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) (AMP-activated protein kinase [AMPK] activator) co-treatment induces significant downregulation of two key fatty acid synthesis regulatory proteins (FASN, Sterol regulatory element-binding protein 1 [SREBP-1c]) as compared to control and Orlistat alone. Orlistat and AICAR co-treatment induced a significant decrease in cell viability and proliferation, and a significant increase in apoptosis in all three PCa cell-lines. Apoptosis induction was preceded by a marked increase in reactive oxygen species (ROS) production followed by G0/G1 cell cycle arrest and activation of pro-apoptotic caspases. We also observed a significant decrease in migration potential and VEGF expression in Orlistat and AICAR co-treated samples in all three PCa cell-lines. Compound C (AMPK inhibitor) negatively affected some of the enhanced anti-cancer effects observed with Orlistat treatment. We conclude that AICAR co-treatment potentiates the anti-proliferative effects of Orlistat at a low dose (100 µM), and this combination has the potential to be a viable and effective therapeutic option in PCa treatment. J. Cell. Biochem. 118: 3834-3845, 2017. © 2017 Wiley Periodicals, Inc.

Topics: Aminoimidazole Carboxamide; Apoptosis; Cell Line, Tumor; Cell Movement; G1 Phase Cell Cycle Checkpoints; Humans; Lactones; Male; Neoplasm Proteins; Orlistat; Prostatic Neoplasms; Reactive Oxygen Species; Resting Phase, Cell Cycle; Ribonucleotides

Taxane-based therapy provides a survival benefit in patients with metastatic prostate cancer, yet the median survival is less than 20 months in this setting due in part to taxane-associated resistance. Innovative strategies are required to overcome chemoresistance for improved patient survival. Here, NanoOrl, a new experimental nanoparticle formulation of the FDA-approved drug, orlistat, was investigated for its cytotoxicity in taxane-resistant prostate cancer utilizing two established taxane-resistant (TxR) cell lines. Orlistat is a weight loss drug that inhibits gastric lipases, but is also a potent inhibitor of fatty acid synthase (FASN), which is overexpressed in many types of cancer. NanoOrl was also investigated for its potential to synergize with taxanes in TxR cell lines. Both orlistat and NanoOrl synergistically inhibited cell viability when combined with paclitaxel, docetaxel, and cabazitaxel in PC3-TxR and DU145-TxR cells, yet these combinations were also additive in parental lines. We observed synergistic levels of apoptosis in TxR cells treated with NanoOrl and docetaxel in combination. Mechanistically, the synergy between orlistat and taxanes was independent of effects on the P-glycoprotein multidrug resistance protein, as determined by an efflux activity assay. On the other hand, immunoblot and immunofluorescence staining with an anti-detyrosinated tubulin antibody demonstrated that enhanced microtubule stability was induced by combined NanoOrl and docetaxel treatment in TxR cells. Furthermore, TxR cells exhibited higher lipid synthesis, as demonstrated by

Topics: Apoptosis; ATP Binding Cassette Transporter, Subfamily B; Cell Line, Tumor; Cell Survival; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Humans; Lactones; Lipid Metabolism; Lipids; Male; Microtubules; Nanoparticles; Orlistat; Prostatic Neoplasms; Protein Stability; Taxoids; Tubulin Modulators

Fatty acid synthase (FASN), the enzyme that catalyzes de novo synthesis of fatty acids, is expressed in many cancer types. Its potential as a therapeutic target is well recognized, but inhibitors of FASN have not yet been approved for cancer therapy. Orlistat (ORL), an FDA-approved lipase inhibitor, is also an effective inhibitor of FASN. However, ORL is extremely hydrophobic and has low systemic uptake after oral administration. Thus, new strategies are required to formulate ORL for cancer treatment as a FASN inhibitor. Here, we report the development of a nanoparticle (NP) formulation of ORL using amphiphilic bioconjugates that are derived from hyaluronic acid (HA), termed Nano-ORL. The NPs were loaded with up to 20 wt % weight of ORL at greater than 95% efficiency. The direct inhibition of the human recombinant thioesterase domain of FASN by ORL extracted from Nano-ORL was similar to that of stock ORL. Nano-ORL demonstrated a similar ability to inhibit cellular FASN activity when compared to free ORL, as demonstrated by analysis of (14)C-acetate incorporation into lipids. Nano-ORL treatment also disrupted mitochondrial function similarly to ORL by reducing adenosine triphosphate turnover in MDA-MB-231 and LNCaP cells. Nano-ORL demonstrated increased potency compared to ORL toward prostate and breast cancer cells. Nano-ORL decreased viability of human prostate and breast cancer cell lines to 55 and 57%, respectively, while free ORL decreased viability to 71 and 79% in the same cell lines. Moreover, Nano-ORL retained cytotoxic activity after a 24 h preincubation in aqueous conditions. Preincubation of ORL dramatically reduced the efficacy of ORL as indicated by high cell viability (>85%) in both breast and prostate cell lines. These data demonstrate that NP formulation of ORL using HA-derived polymers retains similar levels of FASN, lipid synthesis, and ATP turnover inhibition while significantly improving the cytotoxic activity against cancer cell lines.

Topics: Apoptosis; Breast Neoplasms; Cell Proliferation; Drug Compounding; Enzyme Inhibitors; Fatty Acid Synthases; Fatty Acid Synthesis Inhibitors; Female; Humans; Lactones; Male; Mitochondria; Nanoparticles; Orlistat; Prostatic Neoplasms; Tumor Cells, Cultured

Prostate cancer is the most commonly diagnosed malignancy among Western men and accounts for the second leading cause of cancer-related deaths. Prostate cancer tends to grow slowly and recent studies suggest that it relies on lipid fuel more than on aerobic glycolysis. However, the biochemical mechanisms governing the relationships between lipid synthesis, lipid utilization, and cancer growth remain unknown. To address the role of lipid metabolism in prostate cancer, we have used etomoxir and orlistat, clinically safe drugs that block lipid oxidation and lipid synthesis/lipolysis, respectively. Etomoxir is an irreversible inhibitor of the carnitine palmitoyltransferase (CPT1) enzyme that decreases β oxidation in the mitochondria. Combinatorial treatments using etomoxir and orlistat resulted in synergistic decreased viability in LNCaP, VCaP, and patient-derived benign and prostate cancer cells. These effects were associated with decreased androgen receptor expression, decreased mTOR signaling, and increased caspase-3 activation. Knockdown of CPT1A enzyme in LNCaP cells resulted in decreased palmitate oxidation but increased sensitivity to etomoxir, with inactivation of AKT kinase and activation of caspase-3. Systemic treatment with etomoxir in nude mice resulted in decreased xenograft growth over 21 days, underscoring the therapeutic potential of blocking lipid catabolism to decrease prostate cancer tumor growth.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Carnitine O-Palmitoyltransferase; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Enzyme Inhibitors; Epoxy Compounds; Humans; Hypoglycemic Agents; Lactones; Lipid Metabolism; Male; Metabolism; Mice; Mice, Nude; Orlistat; Oxidation-Reduction; Prostatic Neoplasms; Random Allocation; Signal Transduction; Xenograft Model Antitumor Assays

Inhibition of FASN has emerged as a promising therapeutic target in cancer, and numerous inhibitors have been investigated. However, severe pharmacological limitations have challenged their clinical testing. The synthetic FASN inhibitor triclosan, which was initially developed as a topical antibacterial agent, is merely affected by these pharmacological limitations. Yet, little is known about its mechanism in inhibiting the growth of cancer cells. Here we compared the cellular and molecular effects of triclosan in a panel of eight malignant and non-malignant prostate cell lines to the well-known FASN inhibitors C75 and orlistat, which target different partial catalytic activities of FASN. Triclosan displayed a superior cytotoxic profile with a several-fold lower IC50 than C75 or orlistat. Structure-function analysis revealed that alcohol functionality of the parent phenol is critical for inhibitory action. Rescue experiments confirmed that end product starvation was a major cause of cytotoxicity. Importantly, triclosan, C75 and orlistat induced distinct changes to morphology, cell cycle, lipid content and the expression of key enzymes of lipid metabolism, demonstrating that inhibition of different partial catalytic activities of FASN activates different metabolic pathways. These finding combined with its well-documented pharmacological safety profile make triclosan a promising drug candidate for the treatment of prostate cancer.

Topics: 3T3 Cells; 4-Butyrolactone; Animals; Anti-Infective Agents, Local; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Drug Repositioning; Fatty Acid Synthase, Type I; Fatty Acid Synthesis Inhibitors; G1 Phase Cell Cycle Checkpoints; Humans; Lactones; Lipid Metabolism; Male; Mice; Orlistat; Prostatic Neoplasms; Structure-Activity Relationship; Triclosan

Fatty acid synthase (FASN) expression is elevated in several cancers, and this over-expression is associated with poor prognosis. Inhibitors of FASN, such as orlistat, reportedly show antitumor effects against cancers that over-express FASN, making FASN a promising therapeutic target. However, large variations in FASN expression levels in individual tumors have been observed, and methods to predict FASN-targeted therapy outcome before treatment are required to avoid unnecessary treatment. In addition, how FASN inhibition affects tumor progression remains unclear. Here, we showed the method to predict FASN-targeted therapy outcome using radiolabeled acetate uptake and presented mechanisms of FASN inhibition with human prostate cancer cell lines, to provide the treatment strategy of FASN-targeted therapy. We revealed that tumor uptake of radiolabeled acetate reflected the FASN expression levels and sensitivity to FASN-targeted therapy with orlistat in vitro and in vivo. FASN-targeted therapy was noticeably effective against tumors with high FASN expression, which was indicated by high acetate uptake. To examine mechanisms, we established FASN knockdown prostate cancer cells by transduction of short-hairpin RNA against FASN and investigated the characteristics by analyses on morphology and cell behavior and microarray-based gene expression profiling. FASN inhibition not only suppressed cell proliferation but prevented pseudopodia formation and suppressed cell adhesion, migration, and invasion. FASN inhibition also suppressed genes involved in production of intracellular second messenger arachidonic acid and androgen hormones, both of which promote tumor progression. Collectively, our data demonstrated that uptake of radiolabeled acetate is a useful predictor of FASN-targeted therapy outcome. This suggests that [1-(11)C]acetate positron emission tomography (PET) could be a powerful tool to accomplish personalized FASN-targeted therapy by non-invasive visualization of tumor acetate uptake and selection of responsive tumors. FASN-targeted therapy could be an effective treatment to suppress multiple steps related to tumor progression in prostate cancers selected by [1-(11)C]acetate PET.

Topics: Acetic Acid; Adenocarcinoma; Animals; Antineoplastic Agents; Biological Transport; Carbon Radioisotopes; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Proliferation; Enzyme Inhibitors; Fatty Acid Synthase, Type I; Gene Expression; Gene Expression Profiling; Humans; Lactones; Male; Mice; Mice, Inbred NOD; Molecular Targeted Therapy; Neoplasms, Experimental; Orlistat; Prostatic Neoplasms; RNA, Small Interfering

The administration of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the expected cancer therapeutics. However, improvements are required in therapies against TRAIL-resistant tumor cells. We report, here, that the anti-obesity drug orlistat enhances the sensitivity to TRAIL in hormone-refractory prostate cancer (HRPC) cells through two different pathways. The combination of orlistat and TRAIL remarkably induced apoptosis in TRAIL-resistant HRPC, DU145 and PC3 cells. Orlistat induced the expression of death receptor (DR) 5, which is one of the TRAIL receptors, at both the mRNA and protein levels. The suppression of DR5 with siRNA reduced the apoptosis induced by the combination of orlistat and TRAIL, suggesting that the apoptosis was at least partially due to the upregulation of DR5. Although the upregulation by orlistat of CHOP at both mRNA and protein levels was observed in both cell lines, the activation of the DR5 promoter in DU145 cells was CHOP-dependent, but that in PC3 cells was CHOP-independent. Moreover, orlistat induced reactive oxygen species (ROS), and a ROS scavenger diminished the sensitivity to TRAIL through the suppression of CHOP and DR5 expression in both cell lines. These results suggest that there are two pathways of upregulation of DR5 by orlistat, which are the ROS-CHOP pathway and the ROS-direct pathway. In conclusion, orlistat promotes the sensitivity to TRAIL by ROS-mediated pathways in prostate cancer cells, especially in TRAIL-resistant cells. We believe that the combination of orlistat and TRAIL in HRPC is promising as a new chemotherapeutic strategy.

Topics: Anti-Obesity Agents; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Free Radical Scavengers; Humans; Lactones; Male; Orlistat; Promoter Regions, Genetic; Prostatic Neoplasms; Reactive Oxygen Species; Receptors, TNF-Related Apoptosis-Inducing Ligand; Recombinant Proteins; RNA Interference; RNA, Messenger; TNF-Related Apoptosis-Inducing Ligand; Transcription Factor CHOP; Transfection; Up-Regulation

Fatty acid synthase (FAS), the cellular enzyme that synthesizes palmitate, is expressed at high levels in tumor cells and is vital for their survival. Through the synthesis of palmitate, FAS primarily drives the synthesis of phospholipids in tumor cells. In this study, we tested the hypothesis that the FAS inhibitors induce endoplasmic reticulum (ER) stress in tumor cells. Treatment of tumor cells with FAS inhibitors induces robust PERK-dependent phosphorylation of the translation initiation factor eIF2alpha and concomitant inhibition of protein synthesis. PERK-deficient transformed mouse embryonic fibroblasts and HT-29 colon carcinoma cells that express a dominant negative PERK (DeltaC-PERK) are hypersensitive to FAS inhibitor-induced cell death. Pharmacologic inhibition of FAS also induces the processing of X-box binding protein-1, indicating that the IRE1 arm of the ER stress response is activated when FAS is inhibited. Induction of ER stress is further confirmed by the increased expression of the ER stress-regulated genes CHOP, ATF4, and GRP78. FAS inhibitor-induced ER stress is activated prior to the detection of caspase 3 and PARP cleavage, primary indicators of cell death, whereas orlistat-induced cell death is rescued by coincubation with the global translation inhibitor cycloheximide. Lastly, FAS inhibitors cooperate with the ER stress inducer thapsigargin to enhance tumor cell killing. These results provide the first evidence that FAS inhibitors induce ER stress and establish an important mechanistic link between FAS activity and ER function.

Topics: Activating Transcription Factor 4; Animals; Cell Line, Tumor; DNA-Binding Proteins; Drug Interactions; eIF-2 Kinase; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Enzyme Inhibitors; Eukaryotic Initiation Factor-2B; Fatty Acid Synthases; Heat-Shock Proteins; HeLa Cells; HT29 Cells; Humans; Lactones; Male; Mice; Molecular Chaperones; Nuclear Proteins; Orlistat; Phosphorylation; Prostatic Neoplasms; Regulatory Factor X Transcription Factors; Thapsigargin; Transcription Factor CHOP; Transcription Factors

One of the fundamental principles of pharmacology is that most drugs have side effects. Although considerable attention is paid to detrimental side effects, drugs can also have beneficial side effects. Given the time and expense of drug development, it would be particularly exciting if a systematic method could be applied to reveal all of the activities, including the unappreciated actions, of a potential drug. The present study takes the first step along this path. An activity-based proteomics strategy was used to simultaneously identify targets and screen for their inhibitors in prostate cancer. Orlistat, a Food and Drug Administration-approved drug used for treating obesity, was included in this screen. Surprisingly, we find a new molecular target and a potential new application for Orlistat. Orlistat is a novel inhibitor of the thioesterase domain of fatty acid synthase, an enzyme strongly linked to tumor progression. By virtue of its ability to inhibit fatty acid synthase, Orlistat halts tumor cell proliferation, induces tumor cell apoptosis, and inhibits the growth of PC-3 tumors in nude mice.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Division; Enzyme Inhibitors; Fatty Acid Synthases; Humans; Lactones; Male; Mice; Mice, Nude; Orlistat; Prostatic Neoplasms; Tumor Cells, Cultured