RESUMEN
Placental System L amino acid transporter activity is decreased in pregnancies complicated by intrauterine growth restriction (IUGR) and increased in fetal overgrowth. However, it is unknown if changes in the expression/activity of placental Large Neutral Amino Acid Transporter Small Subunit 1 (Slc7a5/LAT1) are mechanistically linked to placental function and fetal growth. We hypothesized that trophoblast-specific Slc7a5 overexpression increases placental transport of essential amino acids, activates the placental mechanistic target of rapamycin (mTOR) signaling, and promotes fetal growth in mice. Using lentiviral transduction of blastocysts with a Slc7a5 transgene, we achieved trophoblast-specific overexpression of Slc7a5 (Slc7a5 OX) with increased fetal (+27%) and placental weights (+10%). Trophoblast-specific Slc7a5 overexpression increased trophoblast plasma membrane (TPM) LAT1 protein abundance and TPM System L transporter (+53%) and System A transporter activity (+ 21%). Slc7a5 overexpression also increased transplacental transport of leucine (+ 85%) but not of the System A tracer, 14C-methylamino isobutyric acid, in vivo. Trophoblast-specific overexpression of Slc7a5 activated placental mTORC1, as assessed by increased (+44%) phosphorylation of S6 ribosomal protein (Ser 235/236), and mTORC2 as indicated by phosphorylation of PKCα-Tyr-657 (+47%) and Akt-Ser 473 (+96%). This is the first demonstration that placental transport of essential amino acids is mechanistically linked to fetal growth. The decreased placental System L activity in human IUGR and the increased placental activity of this transporter in some cases of fetal overgrowth may directly contribute to the development of these pregnancy complications.
RESUMEN
Hearing loss is a pivotal risk factor for dementia. It has recently emerged that a disruption in the intercommunication between the cochlea and brain is a key process in the initiation and progression of this disease. However, whether the cochlear properties can be influenced by pathological signals associated with dementia remains unclear. In this study, using a mouse model of Alzheimer's disease (AD), we investigated the impacts of the AD-like amyloid ß (Aß) pathology in the brain on the cochlea. Despite little detectable change in the age-related shift of the hearing threshold, we observed quantitative and qualitative alterations in the protein profile in perilymph, an extracellular fluid that fills the path of sound waves in the cochlea. Our findings highlight the potential contribution of Aß pathology in the brain to the disturbance of cochlear homeostasis.
Asunto(s)
Enfermedad de Alzheimer , Cóclea , Modelos Animales de Enfermedad , Perilinfa , Animales , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Ratones , Perilinfa/metabolismo , Cóclea/metabolismo , Cóclea/patología , Péptidos beta-Amiloides/metabolismo , Ratones Transgénicos , Pérdida Auditiva/metabolismo , Pérdida Auditiva/patologíaRESUMEN
L-type amino acid transporter 1 (LAT1) is specifically expressed in many malignancies, contributes to the transport of essential amino acids, such as leucine, and regulates the mammalian target of rapamycin (mTOR) signaling pathway. We investigated the expression profile and functional role of LAT1 in prostate cancer using JPH203, a specific inhibitor of LAT1. LAT1 was highly expressed in castration-resistant prostate cancer (CRPC) cells, including C4-2 and PC-3 cells, but its expression level was low in castration-sensitive LNCaP cells. JPH203 significantly inhibited [14C] leucine uptake in CRPC cells but had no effect in LNCaP cells. JPH203 inhibited the proliferation, migration, and invasion of CRPC cells but not of LNCaP cells. In C4-2 cells, Cluster of differentiation (CD) 24 was identified by RNA sequencing as a novel downstream target of JPH203. CD24 was downregulated in a JPH203 concentration-dependent manner and suppressed activation of the Wnt/ß-catenin signaling pathway. Furthermore, an in vivo study showed that JPH203 inhibited the proliferation of C4-2 cells in a castration environment. The results of this study indicate that JPH203 may exert its antitumor effect in CRPC cells via mTOR and CD24.
Asunto(s)
Antígeno CD24 , Movimiento Celular , Proliferación Celular , Transportador de Aminoácidos Neutros Grandes 1 , Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/patología , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Línea Celular Tumoral , Animales , Proliferación Celular/efectos de los fármacos , Antígeno CD24/metabolismo , Ratones , Movimiento Celular/efectos de los fármacos , Vía de Señalización Wnt/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Serina-Treonina Quinasas TOR/metabolismo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Benzoxazoles/farmacología , Leucina/farmacología , Leucina/análogos & derivados , Ratones Desnudos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Tirosina/análogos & derivadosRESUMEN
L-type amino acid transporter 1 (LAT1) is recognized as a promising target for cancer therapy; however, the cellular adaptive response to its pharmacological inhibition remains largely unexplored. This study examined the adaptive response to LAT1 inhibition using nanvuranlat, a high-affinity LAT1 inhibitor. Proteomic analysis revealed the activation of a stress-induced transcription factor ATF4 following LAT1 inhibition, aligning with the known cellular responses to amino acid deprivation. This activation was linked to the GCN2-eIF2α pathway which regulates translation initiation. Our results show that ATF4 upregulation counteracts the suppressive effect of nanvuranlat on cell proliferation in pancreatic ductal adenocarcinoma cell lines, suggesting a role for ATF4 in cellular adaptation to LAT1 inhibition. Importantly, dual targeting of LAT1 and ATF4 exhibited more substantial anti-proliferative effects in vitro than individual treatments. This study underscores the potential of combining LAT1 and ATF4 inhibition as a therapeutic strategy in cancer treatment.
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Regulación hacia Arriba , Proteómica , Aminoácidos/metabolismo , Neoplasias Pancreáticas/tratamiento farmacológico , Carcinoma Ductal Pancreático/tratamiento farmacológico , Transportador de Aminoácidos Neutros Grandes 1/genética , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Línea Celular Tumoral , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismoRESUMEN
Amino acid transporter LAT1 is highly upregulated in various cancer types, including cholangiocarcinoma (CHOL), and contributes to the rapid proliferation of cancer cells and disease progression. However, the molecular mechanisms underlying the pathological upregulation of LAT1 remain largely unknown. This study pursued the possibility of miRNA-mediated regulation of the LAT1 expression in CHOL cells. Using online target prediction methods, we extracted five candidate miRNAs commonly predicted to regulate the LAT1 expression. Three of them, miR-194-5p, miR-122-5p, and miR-126-3p, were significantly downregulated in CHOL cancer compared to normal tissues. Correlation analysis revealed weak-to-moderate negative correlations between the expression of these miRNAs and LAT1 mRNA in CHOL cancer tissues. We selected miR-194-5p and miR-122-5p for further analyses and found that both miRNAs functionally target 3'UTR of LAT1 mRNA by a luciferase-based reporter assay. Transfection of the miRNA mimics significantly suppressed the LAT1 expression at mRNA and protein levels and inhibited the proliferation of CHOL cells, with a trend of affecting intracellular amino acids and amino acid-related signaling pathways. This study indicates that the decreased expression of these LAT1-targeting tumor-suppressive miRNAs contributes to the upregulation of LAT1 and the proliferation of CHOL cells, highlighting their potential for developing novel cancer therapeutics and diagnostics.
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Neoplasias de los Conductos Biliares , Colangiocarcinoma , MicroARNs , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Colangiocarcinoma/genética , Colangiocarcinoma/patología , Línea Celular Tumoral , Conductos Biliares Intrahepáticos/metabolismo , Conductos Biliares Intrahepáticos/patología , Neoplasias de los Conductos Biliares/genética , Neoplasias de los Conductos Biliares/patología , ARN Mensajero/genética , Regulación Neoplásica de la Expresión Génica , Proliferación Celular/genéticaRESUMEN
L-type amino acid transporter 1 (LAT1) is a transmembrane protein responsible for transporting large neutral amino acids. While numerous LAT1-targeted compound delivery for the brain and tumors have been investigated, their LAT1 selectivity often remains ambiguous despite high LAT1 affinity. This study assessed the LAT1 selectivity of phenylalanine (Phe) analogs, focusing on their structure-activity characteristics. We discovered that 2-iodo-L-phenylalanine (2-I-Phe), with an iodine substituent at position 2 in the benzene ring, markedly improves LAT1 affinity and selectivity compared to parent amino acid Phe, albeit at the cost of reduced transport velocity. L-Phenylglycine (Phg), one carbon shorter than Phe, was found to be a substrate for LAT1 with a lower affinity, exhibiting a low level of selectivity for LAT1 equivalent to Phe. Notably, (R)-2-amino-1,2,3,4-tetrahydro-2-naphthoic acid (bicyclic-Phe), with an α-methylene moiety akin to the α-methyl group in α-methyl-L-phenylalanine (α-methyl-Phe), a known LAT1-selective compound, showed similar LAT1 transport maximal velocity to α-methyl-Phe, but with higher LAT1 affinity and selectivity. In vivo studies revealed tumor-specific accumulation of bicyclic-Phe, underscoring the importance of LAT1-selectivity in targeted delivery. These findings emphasize the potential of bicyclic-Phe as a promising LAT1-selective component, providing a basis for the development of LAT1-targeting compounds based on its structural framework.
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Aminoácidos , Fenilalanina , Fenilalanina/metabolismo , Aminoácidos/metabolismo , Encéfalo/metabolismo , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Transporte BiológicoRESUMEN
L-type amino acid transporter 1 (LAT1, SLC7A5) is upregulated in various cancers and associated with disease progression. Nanvuranlat (Nanv; JPH203, KYT-0353), a selective LAT1 inhibitor, suppresses the uptake of large neutral amino acids required for rapid growth and proliferation of cancer cells. Previous studies have suggested that the inhibition of LAT1 by Nanv induces the cell cycle arrest at G0/G1 phase, although the underlying mechanisms remain unclear. Using pancreatic cancer cells arrested at the restriction check point (R) by serum deprivation, we found that the Nanv drastically suppresses the G0/G1-S transition after release. This blockade of the cell cycle progression was accompanied by a sustained activation of p38 mitogen-activated protein kinase (MAPK) and subsequent phosphorylation-dependent proteasomal degradation of cyclin D1. Isoform-specific knockdown of p38 MAPK revealed the predominant contribution of p38α. Proteasome inhibitors restored the cyclin D1 amount and released the cell cycle arrest caused by Nanv. The increased phosphorylation of p38 MAPK and the decrease of cyclin D1 were recapitulated in xenograft tumor models treated with Nanv. This study contributes to delineating the pharmacological activities of LAT1 inhibitors as anti-cancer agents and provides significant insights into the molecular basis of the amino acid-dependent cell cycle checkpoint at G0/G1 phase.
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Ciclina D1 , Neoplasias , Humanos , Ciclina D1/genética , Ciclina D1/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Fase G1 , Fosforilación , Puntos de Control del Ciclo Celular , Proliferación Celular/genéticaRESUMEN
L-type amino acid transporter 1 (LAT1, SLC7A5) is an amino acid transporter expressed in various carcinomas, and it is postulated to play an important role in the proliferation of cancer cells through the uptake of essential amino acids. Cabazitaxel is a widely used anticancer drug for treating castration-resistant prostate cancer (CRPC); however, its effectiveness is lost when cancer cells acquire drug resistance. In this study, we investigated the expression of LAT1 and the effects of a LAT1-specific inhibitor, JPH203, in cabazitaxel-resistant prostate cancer cells. LAT1 was more highly expressed in the cabazitaxel-resistant strains than in the normal strains. Administration of JPH203 inhibited the growth, migration, and invasive ability of cabazitaxel-resistant strains in vitro. Phosphoproteomics using liquid chromatography-mass spectrometry to comprehensively investigate changes in phosphorylation due to JPH203 administration revealed that cell cycle-related pathways were affected by JPH203, and that JPH203 significantly reduced the kinase activity of cyclin-dependent kinases 1 and 2. Moreover, JPH203 inhibited the proliferation of cabazitaxel-resistant cells in vivo. Taken together, the present study results suggest that LAT1 might be a valuable therapeutic target in cabazitaxel-resistant prostate cancer.
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Benzoxazoles , Transportador de Aminoácidos Neutros Grandes 1 , Neoplasias de la Próstata , Taxoides , Tirosina/análogos & derivados , Masculino , Humanos , Fosforilación , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Neoplasias de la Próstata/tratamiento farmacológico , Quinasas Ciclina-Dependientes/metabolismo , Línea Celular TumoralRESUMEN
The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and over 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org/), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.16182. Transporters are one of the six major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, ion channels, nuclear hormone receptors, catalytic receptors and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.