Resveratrol, a novel inhibitor of fatty acid binding protein 5, inhibits cervical cancer metastasis by suppressing fatty acid transport into nucleus and downstream pathways.

BACKGROUND AND PURPOSE: Because of cervical cancer (CC) metastasis, the prognosis of diagnosed patients is poor. However, the molecular mechanisms and therapeutic approach for metastatic CC remain elusive. EXPERIMENTAL APPROACH: In this study, we first evaluated the effect of resveratrol (RSV) on CC cell migration and metastasis. Via an activity-based protein profiling (ABPP) approach, a photoaffinity probe of RSV (RSV-P) was synthesized, and the protein targets of RSV in HeLa cells were identified. Based on target information and subsequent in vivo and in vitro validation experiments, we finally elucidated the mechanism of RSV corresponding to its antimetastatic activity. KEY RESULTS: The results showed that RSV concentration-dependently suppressed CC cell migration and metastasis. A list of proteins was identified as the targets of RSV, through the ABPP approach with RSV-P, among which fatty acid binding protein 5 (FABP5) attracted our attention based on The Cancer Genome Atlas (TCGA) database analysis. Subsequent knockout and overexpression experiments confirmed that RSV directly interacted with FABP5 to inhibit fatty acid transport into the nucleus, thereby suppressing downstream matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression, thus inhibiting CC metastasis. CONCLUSIONS AND IMPLICATIONS: Our study confirmed the key role of FABP5 in CC metastasis and provided important target information for the design of therapeutic lead compounds for metastatic CC.

Identification of a novel fatty acid binding protein-5-CB2 receptor-dependent mechanism regulating anxiety behaviors in the prefrontal cortex.

The endocannabinoid (eCB) system represents a promising neurobiological target for novel anxiolytic pharmacotherapies. Previous clinical and preclinical evidence has revealed that genetic and/or pharmacological manipulations altering eCB signaling modulate fear and anxiety behaviors. Water-insoluble eCB lipid anandamide requires chaperone proteins for its intracellular transport to degradation, a process that requires fatty acid-binding proteins (FABPs). Here, we investigated the effects of a novel FABP-5 inhibitor, SBFI-103, on fear and anxiety-related behaviors using rats. Acute intra-prelimbic cortex administration of SBFI-103 induced a dose-dependent anxiolytic response and reduced contextual fear expression. Surprisingly, both effects were reversed when a cannabinoid-2 receptor (CB2R) antagonist, AM630, was co-infused with SBFI-103. Co-infusion of the cannabinoid-1 receptor antagonist Rimonabant with SBFI-103 reversed the contextual fear response yet showed no reversal effect on anxiety. Furthermore, in vivo neuronal recordings revealed that intra-prelimbic region SBFI-103 infusion altered the activity of putative pyramidal neurons in the basolateral amygdala and ventral hippocampus, as well as oscillatory patterns within these regions in a CB2R-dependent fashion. Our findings identify a promising role for FABP5 inhibition as a potential target for anxiolytic pharmacotherapy. Furthermore, we identify a novel, CB2R-dependent FABP-5 signaling pathway in the PFC capable of strongly modulating anxiety-related behaviors and anxiety-related neuronal transmission patterns.

SAR study on Novel truxillic acid monoester-Based inhibitors of fatty acid binding proteins as Next-Generation antinociceptive agents.

Fatty acid binding protein 5 (FABP5) is a highly promising target for the development of analgesics as its inhibition is devoid of CB1R-dependent side-effects. The design and discovery of highly potent and FABP5-selective truxillic acid (TA) monoesters (TAMEs) is the primary aim of the present study. On the basis of molecular docking analysis, ca. 2,000 TAMEs were designed and screened in silico, to funnel down to 55 new TAMEs, which were synthesized and assayed for their affinity (Ki) to FABP5, 3 and 7. The SAR study revealed that the introduction of H-bond acceptors to the far end of the 1,1'-biphenyl-3-yl and 1,1'-biphenyl-2-yl ester moieties improved the affinity of α-TAMEs to FABP5. Compound γ-3 is the first γ-TAME, demonstrating a high affinity to FABP5 and competing with α-TAMEs. We identified the best 20 TAMEs based on the FABP5/3 selectivity index. The clear front runner is α-16, bearing a 2­indanyl ester moiety. In sharp contrast, no ε-TAMEs made the top 20 in this list. However, α-19 and ε-202, have been identified as potent FABP3-selective inhibitors for applications related to their possible use in the protection of cardiac myocytes and the reduction of α-synuclein accumulation in Parkinson's disease. Among the best 20 TAMEs selected based on the affinity to FABP7, 13 out of 20 TAMEs were found to be FABP7-selective, with α-21 as the most selective. This study identified several TAMEs as FABP7-selective inhibitors, which would have potentially beneficial therapeutic effects in diseases such as Down's syndrome, schizophrenia, breast cancer, and astrocytoma. We successfully introduced the α-TA monosilyl ester (TAMSE)-mediated protocol to dramatically improve the overall yields of α-TAMEs. α-TAMSEs with TBDPS as the silyl group is isolated in good yields and unreacted α-TA/ α-MeO-TA, as well as disilyl esters (α-TADSEs) are fully recycled. Molecular docking analysis provided rational explanations for the observed binding affinity and selectivity of the FABP3, 5 and 7 inhibitors, including their α, γ and ε isomers, in this study.

Fatty Acid-Binding Protein 4 Inhibition Promotes Locomotor and Autonomic Recovery in Rats following Spinal Cord Injury.

The inflammatory response associated with traumatic spinal cord injury (SCI) contributes to locomotor and sensory impairments. Pro-inflammatory (M1) macrophages/microglia (MϕMG) are the major cellular players in this response as they promote chronic inflammation resulting in injury expansion and tissue damage. Fatty acid-binding protein 4 (FABP4) promotes M1 MϕMG differentiation; however, it is unknown if FABP4 also plays a role in the etiology of SCI. The present study investigates whether FABP4's gene expression influences functional recovery following SCI. Analysis of quantitative polymerase chain reaction data shows a robust induction of FABP4 messenger RNA (mRNA; >100 fold) in rats subjected to a T9-T10 contusion injury compared with control. Western blot experiments reveal significant upregulation of FABP4 protein at the injury epicenter, and immunofluorescence analysis identifies that this upregulation occurs in CD11b+ MϕMG. Further, upregulation of FABP4 gene expression correlates with peroxisome proliferator-activated receptor γ (PPARγ) downregulation, inactivation of Iκßα, and the activation of the NF-κB pathway. Analysis of locomotor recovery using the Basso-Beattie-Bresnahan's locomotor scale and the CatWalk gait analysis system shows that injured rats treated with FABP4 inhibitor BMS309403 have significant improvements in locomotion compared with vehicle controls. Additionally, inhibitor-treated rats exhibit enhanced autonomic bladder reflex recovery. Immunofluorescence experiments also show the administration of the FABP4 inhibitor increases the number of CD163+ and liver arginase+ M2 MϕMG within the epicenter and penumbra of the injured spinal cord 28 days post-injury. These findings show that FABP4 may significantly exacerbate locomotor and sensory impairments during SCI by modulating macrophage/microglial activity.

Inhibition of FABP6 Reduces Tumor Cell Invasion and Angiogenesis through the Decrease in MMP-2 and VEGF in Human Glioblastoma Cells.

Malignant glioma is one of the most lethal cancers with rapid progression, high recurrence, and poor prognosis in the central nervous system. Fatty acid-binding protein 6 (FABP6) is a bile acid carrier protein that is overexpressed in colorectal cancer. This study aimed to assess the involvement of FABP6 expression in the progression of malignant glioma. Immunohistochemical analysis revealed that FABP6 expression was higher in glioma than in normal brain tissue. After the knockdown of FABP6, a decrease in the migration and invasion abilities of glioma cells was observed. The phosphorylation of the myosin light chain was inhibited, which may be associated with migration ability. Moreover, expression levels of invasion-related proteins, matrix metalloproteinase-2 (MMP-2) and cathepsin B, were reduced. Furthermore, tube formation was inhibited in the human umbilical vein endothelial cells with a decreased concentration of vascular endothelial growth factor (VEGF) in the conditioned medium after the knockdown of FABP6. The phosphorylation of the extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p65 were also decreased after FABP6 reduction. Finally, the bioluminescent images and immunostaining of MMP-2, cluster of differentiation 31 (CD31), and the VEGF receptor 1 (VEGFR1) revealed attenuated tumor progression in the combination of the FABP6-knocked-down and temozolomide (TMZ)-treated group in an orthotopic xenograft mouse tumor model. This is the first study that revealed the impact of FABP6 on the invasion, angiogenesis, and progression of glioma. The results of this study show that FABP6 may be a potential therapeutic target combined with TMZ for malignant gliomas.

Downregulation of FABP5 Suppresses the Proliferation and Induces the Apoptosis of Gastric Cancer Cells Through the Hippo Signaling Pathway.

Fatty acid binding protein 5 (FABP5) has been reported to play an important role in various cancers. We found that high FABP5 expression was associated with poor histological differentiation and vascular invasion. High FABP5 expression indicated a poor prognosis. Downregulation of FABP5 suppressed cell proliferation, cell migration and invasion, and induced cell apoptosis. Bioinformatic analysis revealed that the Hippo signaling pathway was related to FABP5. We found that overexpression of yes-associated protein 1 (YAP1) could partially reverse the effect of FABP5 knockdown on growth and apoptosis. The FABP5 inhibitor SBFI-26 suppressed the proliferation and promoted the apoptosis of gastric cancer (GC) cells and interfered with the Hippo signaling pathway by inhibiting YAP1. Our data suggested that FABP5 might act as a potential target associated with the Hippo signaling pathway for GC treatment.

Combined treatment with FABP4 inhibitor ameliorates rosiglitazone-induced liver steatosis in obese diabetic db/db mice.

Rosiglitazone has been reported to exert dual effects on liver steatosis, and it could exacerbate liver steatosis in obese animal models, which was suggested to be closely related to the elevated hepatic expression of FABP4. This study aimed to investigate whether combined treatment with FABP4 inhibitor I-9 could alleviate rosiglitazone-induced liver steatosis in obese diabetic db/db mice. Male C57BL/KsJ-db/db mice were orally treated with rosiglitazone, rosiglitazone combined with I-9 daily for 8 weeks. The liver steatosis was evaluated by triglyceride content and H&E staining. The expression of hepatic lipogenic genes or proteins in liver tissue or in FFA-treated hepatocytes and PMA-stimulated macrophages were determined by real-time quantitative polymerase chain reaction (RT-qPCR) or western blotting. Results showed that combined treatment with I-9 decreased rosiglitazone-induced increase in serum FABP4 level and expression of lipogenic genes in liver, especially FABP4, and ameliorated liver steatosis in db/db mice. Rosiglitazone-induced intracellular TG accumulation and increased expression of FABP4 in the cultured hepatocytes and macrophages were also suppressed by combined treatment. We concluded that combined treatment with FABP4 inhibitor I-9 could ameliorate rosiglitazone-exacerbated elevated serum FABP4 level and ectopic liver fat accumulation in obese diabetic db/db mice without affecting its anti-diabetic efficacy.

Genetic and pharmacological inhibition of fatty acid-binding protein 4 alleviated inflammation and early fibrosis after toxin induced kidney injury.

Considerable data have suggested that acute kidney injury (AKI) is often incompletely repaired and could lead to chronic kidney disease (CKD). As we known, toxin-induced nephropathy triggers the rapid production of proinflammatory mediators and the prolonged inflammation allows the injured kidneys to develop interstitial fibrosis. In our previous study, fatty acid-binding protein 4 (Fabp4) has been reported to be involved in the process of AKI. However, whether Fabp4 plays crucial roles in toxin-induced kidney injury remained unclear. To explore the effect and mechanism of Fabp4 on toxin induced kidney injury, folic acid (FA) and aristolochic acid (AA) animal models were used. Both FA and AA injected mice developed severe renal dysfunction and dramatically inflammatory response (IL-6, MCP1 and TNF-a), which further lead to early fibrosis confirmed by the accumulation of extracellular matrix proteins (α-Sma, Fn, Col1 and Col4). Importantly, we found that FA and AA induced-kidney injury triggered the high expression of Fabp4 mRNA/protein in tubular epithelial cells. Furthermore, pharmacological and genetic inhibition of Fabp4 significantly attenuated FA and AA induced renal dysfunction, pathological damage, and early fibrosis via the regulation of inflammation, which is mediated by suppressing p-p65/p-stat3 expression via enhancing Pparγ activity. In summary, Fabp4 in tubular epithelial cells exerted the deleterious effects during the recovery of FA and AA induced kidney injury and the inhibition of Fabp4 might be an effective therapeutic strategy against the progressive AKI.

Thermal Shift Assay for Exploring Interactions Between Fatty Acid-Binding Protein and Inhibitors.

Thermal shift assay (TSA) is a widely used method in discovering potential compounds (e.g., ligands, inhibitors, and other additives) to the target protein for structural genomics and drug screening in both academia and industry. The presence of sensitive fluorescent dye enables to monitor thermal stability of protein and compounds affecting this stability. By using a conventional real-time PCR instrument, it is determined as a low-cost and high efficacy experiment applied to identify optimal conditions for ligand binds to protein. Fatty acid-binding proteins (FABPs) are small molecular proteins in transporting fatty acids and other lipophilic substances in physiological and pathological responses. This chapter presents a comprehensive workflow to monitor recombinant FABP-compound interactions for an initial screening for inhibitors using TSA with SYPRO Orange dye.

Functional inhibition of fatty acid binding protein 4 ameliorates impaired ciliogenesis in GCs.

Ciliogenesis is often impaired in some cancer cells, leading to acceleration of cancer phenotypes such as cell migration and proliferation. From the investigation of primary cilia of 16 gastric cancer cells (GCs), we found that GCs could be grouped into four primary cilia (PC)-positive GCs and 12 PC-negative GCs. The proliferation of the PC-positive GCs was lower than that of PC-negative GCs. To explore the role of fatty acid binding protein 4 (FABP4), which is a known oncogenic factor, in ciliogenesis, FABP4 expression and function were inhibited by transfection of cells with short interfering RNA targeting FABP4 (siFABP4) or FABP4 inhibitor treatment. Notably, the proliferation and migration of the cilia-forming GCs was effectively suppressed by inhibition of FABP4. In addition, the primary cilia in GCs were restored by a factor greater than two, suggesting a negative role of FABP4 in ciliogenesis in these GCs and FABP4 as a potential anticancer target.

FABP4 inhibitor attenuates inflammation and endoplasmic reticulum stress of islet in leptin receptor knockout rats.

OBJECTIVE: Metabolic syndrome is characterized by abdominal obesity, hypertriglyceridemia and hyperglycemia. Fatty acid binding protein 4 (FABP4), as a member of intracellular lipid chaperones, is not only engaged in lipid transport but involved in inflammation and insulin resistance. The present study was to investigate the effects of BMS309403, a specific FABP4 inhibitor, on metabolic syndrome and its possible molecular mechanisms in islets. MATERIALS AND METHODS: Leptin receptor knockout (Lepr-/-) rat, a novel and representative animal model of metabolic syndrome, was adopted in this study. Lepr-/- male rats and their wild littermates were grouped and intragastrically administered with BMS309403. Glucose Tolerance Test (GTT) and Insulin Tolerance Test (ITT) were performed on all rats. Serum insulin was detected by ELISA. The metabolic characters, as well as liver and kidney functions, were evaluated by serum biochemical assay. Immunohistochemistry and Western blot were adopted to detect the expression levels of FABP4, CD68, GRP78, ATF6, p-IRE1a, and Cleaved caspase-3. RESULTS: Lepr-/- rats showed prominent characteristics of metabolic syndrome with increased FABP4, inflammatory infiltration, ER stress and apoptosis in islets. BMS309403 administration attenuated inflammation, ER stress and apoptosis in Lepr-/- rat islets while stimulating insulin secretion as well as improving manifestation of metabolic syndrome without hepatic and renal toxicity. CONCLUSIONS: FABP4 increased in Lepr-/- rat islets and might be involved in the regulation of islet inflammation and apoptosis via ER stress. FABP4 inhibitor BMS309403 could ameliorate islet inflammation and apoptosis in metabolic syndrome through suppressing ER stress.

Network pharmacology of bioactives from Sorghum bicolor with targets related to diabetes mellitus.

BACKGROUND: Sorghum bicolor (SB) is rich in protective phytoconstituents with health benefits and regarded as a promising source of natural anti-diabetic substance. However, its comprehensive bioactive compound(s) and mechanism(s) against type-2 diabetes mellitus (T2DM) have not been exposed. Hence, we implemented network pharmacology to identify its key compounds and mechanism(s) against T2DM. METHODS: Compounds in SB were explored through GC-MS and screened by Lipinski's rule. Genes associated with the selected compounds or T2DM were extracted from public databases, and the overlapping genes between SB-compound related genes and T2DM target genes were identified using Venn diagram. Then, the networking between selected compounds and overlapping genes was constructed, visualized, and analyzed by RStudio. Finally, affinity between compounds and genes was evaluated via molecular docking. RESULTS: GC-MS analysis of SB detected a total of 20 compounds which were accepted by the Lipinski's rule. A total number of 16 compounds-related genes and T2DM-related genes (4,763) were identified, and 81 overlapping genes between them were selected. Gene set enrichment analysis exhibited that the mechanisms of SB against T2DM were associated with 12 signaling pathways, and the key mechanism might be to control blood glucose level by activating PPAR signaling pathway. Furthermore, the highest affinities were noted between four main compounds and six genes (FABP3-Propyleneglyco monoleate, FABP4-25-Oxo-27-norcholesterol, NR1H3-Campesterol, PPARA-ß-sitosterol, PPARD-ß-sitosterol, and PPARG-ß-sitosterol). CONCLUSION: Our study overall suggests that the four key compounds detected in SB might ameliorate T2DM severity by activating the PPAR signaling pathway.

Application of target repositioning and in silico screening to exploit fatty acid binding proteins (FABPs) from Echinococcus multilocularis as possible drug targets.

Fatty acid binding proteins (FABPs) are small intracellular proteins that reversibly bind fatty acids and other hydrophobic ligands. In cestodes, due to their inability to synthesise fatty acids and cholesterol de novo, FABPs, together with other lipid binding proteins, have been proposed as essential, involved in the trafficking and delivery of such lipophilic metabolites. Pharmacological agents that modify specific parasite FABP function may provide control of lipid signalling pathways, inflammatory responses and metabolic regulation that could be of crucial importance for the parasite development and survival. Echinococcus multilocularis and Echinococcus granulosus are, respectively, the causative agents of alveolar and cystic echinococcosis (or hydatidosis). These diseases are included in the World Health Organization's list of priority neglected tropical diseases. Here, we explore the potential of FABPs from cestodes as drug targets. To this end, we have applied a target repurposing approach to identify novel inhibitors of Echinococcus spp. FABPs. An ensemble of computational models was developed and applied in a virtual screening campaign of DrugBank library. 21 hits belonging to the applicability domain of the ensemble models were identified, and 3 of the hits were assayed against purified E. multilocularis FABP, experimentally confirming the model's predictions. Noteworthy, this is to our best knowledge the first report on isolation and purification of such four FABP, for which initial structural and functional characterization is reported here.

Pharmacological inhibition of fatty acid-binding protein 4 alleviated kidney inflammation and fibrosis in hyperuricemic nephropathy.

Hyperuricemia is an independent risk factor for chronic kidney disease (CKD). Excessive uric acid (UA) level in the blood leads to hyperuricemic nephropathy (HN), which is characterized by glomerular hypertension, arteriolosclerosis and tubulointerstitial fibrosis. Fatty acid binding protein 4 (FABP4) is a potential mediator of inflammatory responses which contributes to renal interstitial fibrosis. However, the roles of FABP4 in HN remains unknown. In the study, a mouse model of HN induced by feeding a mixture of adenine and potassium oxonate, severe kidney injury and interstitial fibrosis, as well as the increased kidney-expressed FABP4 protein level were evident, accompanied by the activation of inflammatory responses. Oral administration of BMS309403, a highly selective FABP4 inhibitor, improved renal dysfunction, inhibited the mRNA level of KIM-1 and NGAL, as well as reduced the expression of proinflammatory cytokines and fibrotic proteins in the injured kidneys. BMS309403 treatment also inhibited the FABP4 activity and further suppressed the activation of JAK2-STAT3 and NF-kB P65 signaling pathways in the hyperuricemia-injured kidneys and UA-stimulated human tubular epithelial (HK-2) cells, respectively. In summary, our study for the first time demonstrated that FABP4 played a crucial role in kidney inflammation and fibrosis via the regulation of JAK2-STAT3 and NF-kB P65 pathways in HN mice. The results suggested that FABP4 inhibition might be a promising therapeutic strategy for HN.

FABP4 inhibitor BMS309403 protects against hypoxia-induced H9c2 cardiomyocyte apoptosis through attenuating endoplasmic reticulum stress.

Acute myocardial infarction is characterized by ischaemia-induced cardiomyocyte apoptosis, in which the endoplasmic reticulum (ER) stress plays an important role. The fatty acid-binding protein-4 (FABP4) has been implicated in regulating ER stress and apoptosis. Yet, whether FABP4 is involved in modulating cardiomyocyte apoptosis remains unclarified. By applying an in vitro model of hypoxia-induced apoptosis of H9c2 cardiomyocytes, we found that FABP4 expression was elevated upon hypoxia stimulation, which was further demonstrated to be transcriptionally activated by the hypoxia-inducible factor 1a (HIF-1α). In addition, the pharmacological inhibition of FABP4 with BMS309403 protected against hypoxia-induced apoptosis in cardiomyocytes, indicating that FABP4 induction is detrimental for cardiomyocyte survival under hypoxic condition. Moreover, BMS309403 attenuated ER stress in cardiomyocytes exposed to hypoxia, which, however, was reversed by tunicamycin, an ER stress activator. More importantly, the protective effect of BMS309403 on cardiomyocytes vanished in the presence of tunicamycin. Thus, these observations establish that FABP4 inhibitor BMS309403 reduces hypoxia-induced cardiomyocyte apoptosis through attenuating excessive ER stress, implying that FABP4 inhibition may be of clinical benefit for MI treatment.

Inhibition of fatty acid binding protein 4 attenuates gestational diabetes mellitus.

Accumulatig evidence demonstrated that inflammation is associated with the development of gestational diabetes mellitus (GDM). Fatty acid-binding protein 4 (FABP4) was reported to be involved in immune response. However, the effect of FABP4 in GDM remians unclear. This study focused on the effect of FABP4 in GDM. C57BL/KsJdb/+ (db/+) mice were used for GDM mouse model . BMS-309403 (BMS) was used to inhibit FABP4 levels in GDM mouse model. IL-6 and TNF-α concentrations in serum were determined via ELISA. Serum glucose and insulin concentrations were tested using commercial glucometer and mouse insulin ELISA kit, respectively. IL-6 and TNF-α mRNA and protein levels were detected using RT-PCR and western blot, respectively. FABP4 levels were upregulated in GDM group compared with control group and were positively associated with serum IL-6 and TNF-α levels. FABP4 inhibition by BMS significantly decreased body weight and serum glucose concentrations, increasd serum insulin concentration, suppressed IL-6 and TNF-α expression both in the serum and the pancreas, enhanced little size and inhibited birth weight in GDM mouse model. Inhibition of FABP4 attenuates GDM in genetic mice.

Computational Drug Repurposing Approach to Identify Potential Fatty Acid-Binding Protein-4 Inhibitors to Develop Novel Antiobesity Therapy.

Obesity is a chronic human disorder caused by multiple factors, causing excessive accumulation of fat because of the disparity in take of energy intake with respect to its expenditure. Genetic, environmental, and behavioral factors are having a crucial role in its pathogenesis. Fatty acid-binding protein (FABP) is a superfamily that was involved in the transportation, metabolism, and storage of lipids. The experimental studies have revealed that there is a significant rise in the fatty acid-binding protein-4 (FABP4) expression, and plasma concentration in obese and its downregulation or inhibition can be a potential drug target for obesity. Repurposing of drugs is a trending method for the identification of the newer pharmacological action of an established drug molecule having initially approved indication. It is a cost-effective and economical approach for the development of alternative therapies for existing dreadful diseases in quick succession. Thus, the in silico drug repurposing technique is a highly effective approach for identifying an existing drug molecule having an antiobesity therapeutic activity against the human FABP4, and Floxacillin was selected as safe and effective drug for candidates for developing an antiobesity therapy.

Exploration of Fragment Binding Poses Leading to Efficient Discovery of Highly Potent and Orally Effective Inhibitors of FABP4 for Anti-inflammation.

Fatty-acid binding protein 4 (FABP4) is a promising therapeutic target for immunometabolic diseases, while its potential for systemic inflammatory response syndrome treatment has not been explored. Here, a series of 2-(phenylamino)benzoic acids as novel and potent FABP4 inhibitors are rationally designed based on an interesting fragment that adopts multiple binding poses within FABP4. A fusion of these binding poses leads to the design of compound 3 with an ∼460-fold improvement in binding affinity compared to the initial fragment. A subsequent structure-aided optimization upon 3 results in a promising lead (17) with the highest binding affinity among all the inhibitors, exerting a significant anti-inflammatory effect in cells and effectively attenuating a systemic inflammatory damage in mice. Our work therefore presents a good example of lead compound discovery derived from the multiple binding poses of a fragment and provides a candidate for development of drugs against inflammation-related diseases.

Adipocyte-Induced FABP4 Expression in Ovarian Cancer Cells Promotes Metastasis and Mediates Carboplatin Resistance.

Adipocytes are critical for ovarian cancer cells to home to the omentum, but the metabolic changes initiated by this interaction are unknown. To this end, we carried out unbiased mass spectrometry-based metabolomic and proteomic profiling of cancer cells cocultured with primary human omental adipocytes. Cancer cells underwent significant proteo-metabolomic alteration(s), typified by changes in the lipidome with corresponding upregulation of lipid metabolism proteins. FABP4, a lipid chaperone protein, was identified as the critical regulator of lipid responses in ovarian cancer cells cocultured with adipocytes. Subsequently, knockdown of FABP4 resulted in increased 5-hydroxymethylcytosine levels in the DNA, downregulation of gene signatures associated with ovarian cancer metastasis, and reduced clonogenic cancer cell survival. In addition, clustered regularly interspaced short palindromic repeats (CRISPR)-mediated knockout of FABP4 in high-grade serous ovarian cancer cells reduced metastatic tumor burden in mice. Consequently, a small-molecule inhibitor of FABP4 (BMS309403) not only significantly reduced tumor burden in a syngeneic orthotopic mouse model but also increased the sensitivity of cancer cells toward carboplatin both in vitro and in vivo. Taken together, these results show that targeting FABP4 in ovarian cancer cells can inhibit their ability to adapt and colonize lipid-rich tumor microenvironments, providing an opportunity for specific metabolic targeting of ovarian cancer metastasis. SIGNIFICANCE: Ovarian cancer metastatic progression can be restricted by targeting a critical regulator of lipid responses, FABP4.