Expression Of LAT1 Research Articles

Enhancement of chemoresistance by claudin-1-mediated formation of amino acid barriers in human lung adenocarcinoma A549 cells

Claudin-1 (CLDN1) is highly expressed in human lung adenocarcinoma-derived A549 cells and is involved in the augmentation of chemoresistance. However, the mechanism of chemoresistance is not fully understood. In the tumor microenvironment, cancer cells are exposed to stress conditions such as hypoxia and malnutrition. Here, we investigated the effect of CLDN1 expression on amino acid (AA) flux and chemoresistance using A549 cells. The expression of L-type AA transporters, LAT1 and LAT3, was decreased by CLDN1 silencing in A549 spheroids. A reduction in extracellular AA concentration increased the expression of these AA transporters in two-dimensional (2D) cultured cells. The paracellular AA flux except for Ser, Thr, Tyr, Ala, and Gly was enhanced by CLDN1 silencing. These results suggest that CLDN1 forms a paracellular barrier to some AAs, leading to the elevation of LAT1/3 expression in spheroids. The production of reactive oxygen species in the mitochondria and cytosol was decreased by CLDN1 silencing in spheroids, resulting in downregulation of the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its target antioxidant genes. CLDN1 silencing enhanced the cytotoxicity of anticancer drugs including doxorubicin and cisplatin, which was blocked by sulforaphane, an inducer of Nrf2 signaling. Similarly, the anticancer-induced toxicity was enhanced by Nrf2 silencing. In 2D cultured cells, the anticancer-induced toxicity was attenuated by AA deficiency and sulforaphane. We suggest that CLDN1 forms an AA barrier in spheroids, leading to the augmentation of Nrf2-dependent chemoresistance in A549 cells.

Multilayered proteomics reveals that JAM-A promotes breast cancer progression via regulation of amino acid transporter LAT1.

Recent studies have shown that transmembrane-type tight junction proteins are upregulated in various cancers compared with their levels in normal tissues and are involved in cancer progression, suggesting that they are potential therapeutic targets. Here, we demonstrated the expression profile and a novel role of junctional adhesion molecule-A (JAM-A) in breast cancer. Immunohistochemistry of surgical specimens showed that JAM-A was highly expressed from carcinoma insitu lesions, as in other adenocarcinomas, with higher expression in invasive carcinomas. High expression of JAM-A contributed to malignant aspects such as lymph node metastasis and lymphatic involvement positivity. In breast cancer cells, JAM-A expression status affects malignant potentials including proliferation and migration. Multilayered proteomics revealed that JAM-A interacts with the amino acid transporter LAT1 in breast cancer cells. JAM-A regulates the expression of LAT1 and interacts with it on the whole cell membrane, leading to enhanced amino acid uptake to promote tumor growth. Double high expression of JAM-A and LAT1 predicts poor prognosis in patients with breast cancer. Of note, an antibody against an extracellular domain of JAM-A suppressed the proliferation of breast cancer cells. Our findings indicate the possibility of JAM-A-targeted therapy ideally combined with LAT1-targeted therapy as a new therapeutic strategy against breast cancer.

BNCT pancreatic cancer treatment strategy with glucose-conjugated boron drug

Multidisciplinary therapy centered on radical surgery for resectable pancreatic cancer is expected to prolong prognosis, but relies on CA19-9 biomarker levels to determine treatment strategy. Boron neutron capture therapy (BNCT) is a chemoradiotherapy using tumor hyperaccumulator boron drugs and neutron irradiation. The purpose of this study is to investigate novel boron drug agents for BNCT for pancreatic cancer. Bioinformatics was used to evaluate the uptake of current boron amino acid (BPA) drugs for BNCT into pancreatic cancer. The expression of the amino acid transporter LAT1, a BPA uptake transporter, was low in pancreatic cancer and even lower in high CA19-9 pancreatic cancer. In contrast, the glucose transporter was high in high CA19-9 pancreatic cancers and inversely correlated with LAT1 expression. Considering the low EPR effect in pancreatic cancer, we synthesized a small molecule Glucose-BSH, which is boron BSH bound to glucose, and confirmed its specific uptake in pancreatic cancer. uptake of Glucose-BSH was confirmed in an environment compatible with the tumor microenvironment. The therapeutic efficacy and safety of Glucose-BSH by therapeutic neutron irradiation were confirmed with BNCT. We report Glucose-BSH boron drug discovery study of a Precision Medicine BNCT with application to high CA19-9 pancreatic cancer.

Sex differences in cachexia and branched-chain amino acid metabolism following chemotherapy in mice.

Chemotherapy is a major contributor to cachexia, but studies often investigate male animals. Here, we investigated whether sex modifies the effects of chemotherapy on cachexia and BCAA metabolism. Ten-week-old CD2F1 male and female mice were treated with the chemotherapy drug cocktail folfiri (50 mg/kg 5-fluorouracil, 90 mg/kg leucovorin, and 24 mg/kg CPT11) (drug) or vehicle twice a week for 6 weeks. Insulin tolerance tests were conducted and BCAA levels and metabolism were measured in plasma and tissues. Drug treatment reduced body and skeletal muscle weights and anabolic signaling in both sexes, with females showing worsened outcomes (p < 0.05 for all). Drug treatment increased plasma BCAA only in males, but BCAA concentrations in the skeletal muscle of both sexes were decreased; this decrease was more profound in males (p = 0.0097). In addition, muscle expression of the BCAA transporter LAT1 was reduced; this reduction was more severe in females (p = 0.0264). In both sexes, the (inhibitory) phosphorylation of BCKD-E1αser293 was increased along with decreased BCKD activity. In the liver, drug treatment increased BCAA concentrations and LAT1 expression, but BCKD activity was suppressed in both sexes (p < 0.05 for all). Our results demonstrate that altered BCAA metabolism may contribute to chemotherapy-induced cachexia in a sex-dependent manner.

L-type amino acid transporter 1 inhibitor JPH203 prevents the growth of cabazitaxel-resistant prostate cancer by inhibiting cyclin-dependent kinase activity.

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 invitro. 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 invivo. Taken together, the present study results suggest that LAT1 might be a valuable therapeutic target in cabazitaxel-resistant prostate cancer.

Effects of late gestational nutrient restriction on uterine artery blood flow, placental size, and cotyledonary mRNA expression in primiparous beef females.

Fall-calving primiparous beef females [body weight (BW): 451 ± 28 (SD) kg; body condition score (BCS): 5.4 ± 0.7] were individually-fed either 100% (control; CON; n = 13) or 70% (nutrient restricted; NR; n = 13) of metabolizable energy and metabolizable protein requirements for maintenance, pregnancy, and growth from day 160 of gestation to parturition. Doppler ultrasonography of both uterine arteries was conducted pre-treatment and every 21 d from days 181 to 265 of gestation. Expelled placentas were collected, and ipsilateral cotyledonary tissue was sampled to assess relative messenger ribonucleic acid (mRNA) expression. Placentas were separated into ipsilateral and contralateral sides, dissected (cotyledonary vs. intercotyledonary), and dried. Data were analyzed with nutritional plane, treatment initiation date, and calf sex (when P < 0.25) as fixed effects. Uterine blood flow included day and nutritional plane × day as repeated measures. We previously reported that post-calving, NR dams weighed 64 kg less and were 2.0 BCS lower than CON, but calf birth weight was not affected. Maternal heart rate was less (P < 0.001) for NR dams than CON after nutritional planes began. Nutritional plane did not affect (P ≥ 0.20) uterine artery hemodynamics, but all variables were affected (P ≤ 0.04) by day. Contralateral cotyledonary and placental weight were less (P ≤ 0.04) and contralateral intercotyledonary weight and number of cotyledons tended to be less (P ≤ 0.10) for NR dams than CON, but ipsilateral and whole placental weights were not affected (P ≥ 0.13). Ipsilateral placental weight as a percentage of total placental weight was greater (P = 0.03) for NR dams than CON. Whole placental cotyledonary: intercotyledonary weight was less (P = 0.01) for NR dams than CON. Placental efficiency was not affected (P = 0.89) by nutritional plane. Cotyledonary relative mRNA expression of GLUT3 and SNAT2 was greater (P ≤ 0.05) and relative expression of GLUT1, GLUT4, and NOS3 tended to be greater (P ≤ 0.07) for NR dams than CON. Nutritional plane did not affect (P ≥ 0.13) relative mRNA expression of GLUT5, 4F2hc, CAT1, LAT1, LAT2, VEGFA, FLT1, KDR, GUCY1B3, and PAG2. Despite less contralateral placental growth, beef heifers experiencing late gestational nutrient restriction maintained uterine artery blood flow and total placental mass and had 4 nutrient transporters and 1 angiogenic factor upregulated in cotyledons, all of which likely contributed to conserving fetal growth.

Prognostic value of large amino acid transporter type 1 (LAT1) expression in pulmonary adenocarcinoma: A tissue microarray study

BackgroundLarge amino acid transporter type 1 (LAT1) provides cancer cells with essential amino acids for both protein synthesis and cell growth and may predict patient prognosis. Additionally, LAT1 inhibition can be a therapeutic target. This study aimed to examine the prognostic significance of LAT1 expression in lung cancer, paying special attention to adenocarcinoma subtypes. MethodsTissue microarrays (TMA) of 1,560 total cores obtained from surgically resected lung cancer specimens between 1995 and 2008 at our hospital were used. Overall, 795 cases of adenocarcinoma were identified, and 717 underwent further evaluation. Immunohistochemical staining of whole slides and TMA cores were assessed to set H-score cutoff value.. Immunohistochemical expression of LAT1 was examined based on the subtypes of adenocarcinoma. Statistical analyses explored the prognostic significance of LAT1. ResultsAdenocarcinoma accounted for 71.8% of all cases (n = 795), and 216 cases (27.1%) expressed LAT1. The 795 cases were categorized into five subtypes: lepidic (n = 29, 3.6%), papillary (n = 601, 75.6%), acinar (n = 58, 7.3%), and solid (n = 9, 1.1%); 717 of the 795 cases were further assessed according to the exclusion criteria. The LAT1-positive ratio increased as the architectural grade increased. Notably, in papillary adenocarcinoma, the LAT1-positive group had significantly lower overall survival compared to the negative group (10-year survival: 45.6% vs. 60.8%, p < 0.001). ConclusionLAT1 expression was higher in high-grade subtypes of pulmonary adenocarcinoma. Moreover, LAT1 expression is useful for predicting prognosis, particularly in papillary adenocarcinoma, facilitating prognostic stratification of papillary adenocarcinoma.

Successful anti-tumor effects with two novel bifunctional chemotherapeutic compounds that combine a LAT1 substrate with cytotoxic moieties in aggressive T-cell lymphomas

T-cell lymphomas are aggressive neoplasms characterized by poor responses to current chemotherapeutic agents. Expression of the l-type amino acid transporter 1 (LAT 1, SLC7A5) allows for the expansion of healthy T-cell counterparts, and upregulation of LAT1 has been reported in precursor T-cell acute leukemia. Therefore, the expression of LAT1 was evaluated in a cohort of cutaneous and peripheral T-cell lymphomas. The findings demonstrated that LAT1 is upregulated in aggressive variants and absent in low-grade or indolent disease such as mycosis fungoides. In addition, upregulated LAT1 expression was seen in a large proportion of aggressive peripheral T-cell lymphomas, including peripheral T-cell lymphoma not otherwise specific (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL). The anti-tumor effects of two novel non-cleavable and bifunctional compounds, QBS10072S and QBS10096S, that combine a potent cytotoxic chemotherapeutic domain (tertiary N-bis(2-chloroethyl)amine) with the structural features of a selective LAT1 substrate (aromatic β-amino acid) were tested in vitro and in vivo in T-cell lymphoma cell lines. The findings demonstrated decreased survival of T-cell lymphoma lines with both compounds. Overall, the results demonstrate that LAT1 is a valuable biomarker for aggressive T-cell lymphoma counterparts and QBS10072S and QBS10096S are successful therapeutic options for these aggressive diseases.

Effect of Phytobiotics and Antibiotic on Growth Performance, Intestinal Morphology and Nutrients Transporters Expression of Broiler Chickens

This study investigated the effect of Phytobiotics (PB) and Antibiotic Growth Promoter (AGP) on performance, intestinal morphology and nutrients transporters mRNA gene expression of broiler chickens. One hundred eighty unsexed one-day-old Ross strains with an average initial body weight (BW) of 45 ± 0.5 g were randomly assigned into three treatments with six replications of 10 chicks in each pen. (1) Control group (CON), basal diets only; (2) antibiotic group, Antibiotic Growth promoter (AGP), basal diet supplemented with 5 mg/kg tetramycin; (3) Phytobiotics (PB), basal diet supplemented with 0.5g/kg, phytobiotics the research lasted for 42 days. Average Daily Feed Intake (ADFI), Average Daily Gain (ADG) and Feed Conversion Ratio (FCR) were calculated weekly, and intestinal morphology of Villus Height (VH), Crypt Depth (CD), and Villus Height to crypt depth ratio (VH: CD) from the duodenum, jejunum, and ileum, nutrients transporters qRT-PCR mRNA expression of GLUT1, SGLT4, GLUT5, PEPT2, CAT1, and LAT1 were evaluated at day 42. Chicks fed PB had significantly (P=0.0413) higher ADG at 1-42 days, PB and AGP significantly had lower FCR (P=0.0001) and (P=0.0001) at 22-42 d and 1-42 days, respectively, in duodenum the villus height was significantly (P=0.0001) longer in PB fed chickens and the lowest was recorded in CON, while the CD and VH: CD were significantly longer in AGP and PB fed chickens, in jejunum VH and CD were significant (P=0.0001) longer in PB and AGP than the CON fed chickens, in ileum PB fed birds had significant higher VH and CD than the AGP and CON fed groups, in duodenum and ileum GLUT1, SGLT4 and GLUT5 expression were highly expressed in AGP and PB fed chickens similar results was obtained in jejunum and ileum by PEPT2 and CAT1. These findings suggest that supplementing phytobiotics in broiler diets improves growth performance and intestinal morphology and up-regulated the expression of nutrient transporters' genes. However, the underlying detailed biological mechanisms and dose standardisation for inclusion in broiler diets need to be further studied.

Overexpression of the LAT1 in primary human trophoblast cells increases the uptake of essential amino acids and activates mTOR signaling.

The System L amino acid transporter, particularly the isoform Large Neutral Amino Acid Transporter Small Subunit 1 (LAT1) encoded bySLC7A5, is believed to mediate the transfer of essential amino acids in the human placenta. Placental System L amino acid transporter expression and activity is decreased in pregnancies complicated by IUGR and increased in fetal overgrowth. However, it remains unknown if changes in the expression of LAT1 are mechanistically linked to System L amino acid transport activity. Here we combined overexpression approaches with protein analysis and functional studies in cultured primary human trophoblast (PHT) cells to test the hypothesis that SLC7A5overexpression increases the uptake of essential amino acids and activates mTOR signaling in PHT cells. Overexpression of SLC7A5 resulted in a marked increase in protein expression of LAT1 in the PHT cells microvillous plasma membrane and System L amino acid transporter activity. Moreover, mTOR signaling was activated, and System A amino acid transporter activity increased following SLC7A5overexpression, suggesting coordination of trophoblast amino transporter expression and activity to ensure balanced nutrient flux to the fetus. This is the first report showing that overexpression of LAT1 is sufficient to increase the uptake of essential amino acids in PHT cells, which activates mTOR, a master regulator of placental function. The decreased placental System L activity in human IUGR and the increased placental activity of this transporter system in some cases of fetal overgrowth may directly contribute to changes in fetal amino acid availability and altered fetal growth in these pregnancy complications.

OR14-02 The Thyroid Hormone Analogs DITPA And TRIAC Triggered T3-signalling In Human MCT8-deficient Brain Organoids

Abstract Disclosure: F. Salas Lucia: None. A.M. Dumitrescu: None. S. Refetoff: None. Patients with mutations in the X chromosome-linked thyroid hormone (TH) cell transporter MCT8 gene have brain hypothyroidism, resulting in severe neuro-psychomotor retardation for which treatment remains very challenging. Potential new treatments using the TH-analogues 3,5-diiodothyropropionic acid (DITPA) and 3,3’,5-triiodothyroacetic acid (TRIAC) have been explored in Mct8-deficient mice. However, given species differences in brain TH transporters, in vitro models using human cells are needed. Here, we generated human brain organoids (BOs) from 4 lines of human induced pluripotent stem cells (hiPSCs). Two lines were derived from MCT8-deficient patients. The other two lines were used as controls: one isogenic line in which the MCT8 mutation has been corrected using CRISPR/Cas9, and a line derived from the unaffected father. Control BOs showed multiple large and continuous neuroepithelia surrounding a ventricle and expressed forebrain markers (FOXG1, and LHX2) at 10-fold higher levels than the hiPSCs. After 20 days in culture, BOs expressed TH transporters; the most abundant being MCT8, trailed by LAT2, LAT1, and MCT10. In contrast, the MCT8-deficient BOs exhibit a 3-fold decrease in the relative expression of LAT2, compared to controls. All BOs showed a similar expression of the deiodinase type 3 (DIO3), and the TH nuclear receptor beta (THRB) genes; the DIO2 and THRA expression were undetectable. Additionally, all four BOs expressed the neuronal and glial markers NEUN and GFAP (5.1±2.0, and 7.3±3.8-fold expression, respectively). Immunohistochemistry using fluorescent antibodies confirmed the presence of postmitotic neurons (TUJ1+) expressing MCT8 in the BOs. Next, we measured the D3 activity. BOs were incubated with T3I125, which resulted in a prominent peak of T2I125 measured using an ultra-high-performance liquid chromatography linked to a gamma counter. The peak of T2I125 indicates the uptake of T3I125 into the neural cells residing in the BOs, its metabolism, and the release of T2I125 in the medium. MCT8-deficient BOs exhibited a D3 activity of 5.3±3.1 pmol/mg/h, a 70% less when compared to the 18.4±7.7 pmol/mg/h of controls. When control BOs were incubated with the MCT8 inhibitor Silychristin 2µM, they exhibited 4.4±3.0 pmol/mg/h D3 activity, like MCT8-deficient BOs. Next, BOs were incubated for 24h with either 10nM L-T3, 10nM TRIAC, or 3.5μM DITPA and T3-responsive genes were studied. Treatment with L-T3 upregulated by 2-fold the gene KLF9 in all four BOs, suggesting that the T3-signalling in the MCT8-deficient BOs might not be compromised. The genes HAIRLESS and DIO3 were unresponsive. In parallel, incubation with DITPA and TRIAC also upregulated KLF9 by 1.5-fold, representing a proof of concept for these thyromimetic molecules to act in human neural cells. This human cell model may be used as a platform to screen therapeutic drugs for MCT8 deficiency. Presentation: Friday, June 16, 2023

Targeting upregulation of the immunosuppressive activity of MDSCs with indirubin as a novel strategy to alleviate psoriasis

BackgroundPsoriasis is a chronic and incurable skin disorder that causes inflammation. There is an urgent clinical need for new treatments. We identified the natural compound indirubin as a potential potent agent for the treatment of psoriasis, but it's therapeutic effect and underlying mechanisms were not well understood. MethodsPeripheral blood and skin tissues from psoriasis patients and healthy individuals were collected. Bioinformatics analysis was performed to investigate LAT1 expression and associated signal pathways in psoriasis skin lesions. A mouse model of psoriasis was established. Indirubin was administered separately or in combination with MDSCs depletion or adoptively transferred MDSCs. JPH203, rapamycin, siRNA, and NV5138 were further used to investigate the potential mechanism by which indirubin regulates MDSCs. ResultsPsoriasis patients had increased numbers of MDSCs in their blood and skin lesions, with high expression of Lat1. The upregulation of LAT1 expression and the arginine synthesis pathway was observed in psoriasis skin lesions. The number of MDSCs was increased, while their inhibitory effect on psoriatic T cells was decreased. Indirubin decreased Lat1 expression on the surface of MDSCs, inhibited mTOR pathway activation, upregulated Arg1 expression in MDSCs, and enhanced the immunosuppressive activity of MDSCs while inhibiting CD4+CCR6+ T cells. ConclusionThis study demonstrates indirubin's pharmacological and therapeutic effects, providing a basis for future clinical application in treating psoriasis.

Subgroup analysis of double-blind, placebo-controlled Ph. 2 study of nanvuranlat in treatment of pre-treated, advanced, refractory biliary tract cancer (BTC): Patients with high LAT1 expression and response to nanvuranlat.

4011 Background: L-type amino acid transporter 1 (LAT1, SLC7A5) is overexpressed in cancer cells leading to aggressive proliferation and lymphatic metastases. LAT1 sustains energy resources by supplying essential amino acids to the TCA cycle in chemotherapy-resistant cancer cells. LAT1 is a documented marker of poor prognosis. In a placebo-controlled, randomized trial involving patients with pre-treated, advanced, refractory biliary tract cancer (BTC), monotherapy with nanvuranlat (JPH203), a selective LAT1 inhibitor, demonstrated a significant improvement in progression free survival (PFS) compared to placebo. Subgroup analysis was conducted to determine whether the level of expression of LAT1 affects nanvuranlat efficacy. Methods: Patients with four different subtypes of advanced BTC were enrolled: intrahepatic and extrahepatic cholangiocarcinoma, and gallbladder and ampulla of Vater cancers. All were refractory to or intolerant of standard chemotherapy and other investigational medicines. Our analysis compared efficacy and safety in the subgroup with high LAT1 expression and all patients group. LAT1 expression was immunohistochemically evaluated in tumor specimens of BTC patients at baseline, as defined by Yanagisawa N, et al. (Cancer Med 2014). Results: At data cut-off (Feb 28, 2022), 211 BTC patients consented at 14 centers in Japan, and 104 patients were randomized (2:1) to nanvuranlat (n = 69) or placebo (n = 35) as the full analysis set (FAS) population. Among the samples immunohistochemically evaluable for LAT1, 62.5% had high LAT1 expression. There was no significant difference in background demography between all patient group and the high-LAT1 subgroup. Nanvuranlat met its primary endpoint (FAS by the blinded independent central review (BICR)), demonstrating a statistically significant improvement in PFS by BICR in comparison with the placebo group. The hazard ratios were further improved with nanvuranlat versus placebo, on analysis of the high-LAT1 subgroup of patients in both PFS and OS. Safety was comparable between nanvuranlat and placebo, on analysis of the high-LAT1 subgroup. Conclusions: This subgroup analysis indicates that the efficacy of nanvuranlat in PFS and OS is enhanced in BTC patients with high LAT1 expression, when compared with placebo. Safety profiles were similar for nanvuranlat- and placebo-treated patients in this subgroup analysis. Clinical trial information: UMIN000034080 . [Table: see text]

Effect of birth rank, and placentome subtype on expression of genes involved in placental nutrient transport in sheep

Placental function is a key determinant of fetal growth and development that can be influenced by maternal and fetal environmental factors. The molecular mechanisms by which the placenta senses and responds to environmental cues are poorly understood. This exploratory study aimed to characterize the effect of birth rank (single vs. twin) and placentome morphologic subtype on expression of genes involved in nutrient transport, angiogenesis, immunity and stress response. Cotyledonary tissue was collected from type A, B and C placentomes from five single and six twin fetuses at 140 days of gestation. GLUT1 and GLUT3 were the most highly expressed genes consistent with the high demand for glucose to support fetal growth. Expression of BCKDHβ and IGF-2 was 1.3- and 1.5-fold higher, respectively, and PCYT1A was 3-fold lower in singles compared to twins (P < 0.05) while no other differences in gene expression were observed between birth ranks. Expression of EAAT2 and LAT2 was higher while PCYT1A was lower in A compared to B type cotyledons. Expression of GUCY1B1/3 and IGF-1 was higher while CD98 and LAT2 were lower in type B compared to C cotyledons (P < 0.05). Compared to type C cotyledons, expression of EAAT2, IGF-1, IGF-2, LAT1 was higher, while TEK was lower in type A cotyledons. The effects of birth rank on placental gene expression in this study indicated that placental nutrient transport and/or function differs between single and twin pregnancies in sheep. Differences in gene expression between the placentome subtypes suggests that changes in placentome morphology are associated with shifts in amino acid transport and metabolism, oxidative stress and angiogenesis and/or blood flow. This study highlights that placental gene expression differs in response to birth rank and placentome morphologic subtype which suggests that both maternal and fetal factors may influence placental function in sheep. These associations provide insights into gene pathways for more targeted future investigations as well as potential adaptations to improve placental efficiency to support fetal growth in twin pregnancies.

Effects of Fish Meal Replacement with Composite Mixture of Soybean Protein Hydrolysates and Other Plant Proteins on Growth Performance, Antioxidant Capacity, and Target of Rapamycin Pathway in Largemouth Bass

AbstractA feeding trial was conducted to evaluate the effect of fish meal replacement with a composite mixture of soybean protein hydrolysates and other plant proteins on growth performance, antioxidant capacity, and target of rapamycin pathway in Largemouth Bass Micropterus salmoides. Triplicate groups of Largemouth Bass were fed the diet formulated with 40% (FM40; control), 35% (FM35), 30% (FM30), or 25% (FM25) fish meal for 10 weeks. The results revealed that the best growth performance was achieved in the FM35 group, while a negative effect on growth was observed in the FM25 group. The feed intake of the FM30 and FM25 groups was significantly lower than the other two groups, while no significant difference was observed in feed efficiency ratio and protein efficiency ratio. No statistical difference was observed in the activity of serum alanine transaminase and aspartate transaminase with the replacement of fish meal. However, the replacement of fish meal with composite plant protein significantly reduced hepatic malondialdehyde content, and a significant improvement in total antioxidant capacity was observed in the FM35 group. Gene expression analysis revealed that the expression of amino acid transporter LAT1 was significantly elevated in the FM35 group, while no significant difference was observed in the LAT2 expression among different treatments. No significant difference was observed in the expression of target of rapamycin among treatments. However, the expression of ribosomal protein S6 in the FM35 and FM30 groups was significantly higher than in the other two groups, while the replacement of fish meal significantly decreased the expression of eukaryotic initiation factor 4EBP1. In summary, the composite mixture of soybean protein hydrolysates and other plant proteins can reduce the use of fish meal from 40% to 35%.

Nanvuranlat, an L-type amino acid transporter (LAT1) inhibitor for patients with pretreated advanced refractory biliary tract cancer (BTC): Primary endpoint results of a randomized, double-blind, placebo-controlled phase 2 study.

494 Background: LAT1 is a transporter ( SLC7A5) of L-type amino acid. Overexpression in cancer cells supports aggressive proliferation. High expression of LAT1 in tumor specimens has been identified as a predictor of poor prognosis in patients with various cancer types, including BTC. The efficacy and safety of nanvuranlat (JPH203), a first-in-class, single agent that selectively inhibits LAT1, was evaluated in patients with pretreated, advanced, refractory BTC in a placebo-controlled randomized trial. Methods: Patients with four different subtypes of advanced BTC were enrolled: intrahepatic (IHC), extrahepatic (EHC), gallbladder (GBC) and ampulla of Vater (AVC). All were refractory to or intolerant of standard chemotherapy and other investigational medicines. Patients were pre-classified as non-rapid acetylators via N-acetyltransferase 2 ( NAT2), to maximize efficacy/safety by minimizing the metabolism of nanvuranlat. The primary endpoint was progression-free survival (PFS), assessed by blinded independent center review (BICR), using RECIST 1.1. Results: At data cut-off (February 28, 2022), 211 BTC patients were consented at 14 centers in Japan. Using NAT2 testing for classification, a total of 106 patients were randomized (2:1) to nanvuranlat (n = 70) or placebo (n = 36). Nanvuranlat met its primary endpoint and demonstrated a statistically significant improvement in PFS by BICR in comparison with the placebo group (Hazard Ratio = 0.557; 95% CI, 0.3435 – 0.9029; one-sided p = 0.0164). The disease control rate (DCR) in the nanvuranlat group was approximately 25% (average = 24.6%) across all BTC subtypes, while it was 11.4% in the placebo group. Grade 3 adverse events were reported in 30.0% for nanvuranlat vs 22.9% for placebo. Treatment-related adverse event rates were respectively 41.4% and 57.1% in the nanvuranlat and placebo groups. No patient had adverse events leading to nanvuranlat treatment discontinuation, dose reduction, or death. Conclusions: The study met the primary endpoint. LAT1 inhibitor monotherapy with nanvuranlat demonstrated useful clinical efficacy in patients with four different subtypes of pre-treated, advanced, refractory BTC. Safe and highly tolerated profile was also documented. Clinical trial information: UMIN000034080 .

Effects of dietary valine-to-lysine ratio on placenta growth, the placental nutrient transporters, and reproductive performance in sows

Context Valine-to-lysine ratio (V:L) in the diet has been found to affect the placental development of sows, and thus the production performance, but the mechanism is still unclear. Aim To investigate the effects of the V:L on placental growth and reproductive performance of sow. Methods Twenty-seven sows (average parities = 5) from 85 days of gestation were randomly assigned into five experimental groups with five ratios of total V:L of 0.75:1, 0.87:1, 0.99:1, 1.11:1, 1.23:1. Litter size was recorded. The placenta and colostrum were collected immediately after farrowing for mRNA analysis. Key results The results showed that dietary valine increased the sows’ placental area and the fetal-to-placental weight ratio (P &lt; 0.05). Dietary valine does not affect the litter size of sows, but significantly reduces the delivery time and accelerates the delivery process. Dietary valine improved the average daily feed intake of the sows in the lactation (P &lt; 0.05) and decreased the number of stillborns (P &lt; 0.05). Additionally, the placental gene expression of LAT1, 4F2hc, LAT2, LAT3, SNAT1, SNAT2, and SNAT4 increased in the groups whose diet contained higher V:L ratios (P &lt; 0.01). The increase in the ratio of dietary V:L increased the expression of GLUT1, GLUT3 and GLUT4 genes in the placenta tissue (P &lt; 0.01). Conclusions The results suggested that suitable V:L positively affects pregnant and lactating sow’s performance. Implications Therefore, V:L can be adjusted to promote sow reproductive performance and increase production efficiency.

Correlation between the expression of LAT1 in cancer cells and the potential efficacy of boron neutron capture therapy.

Boron neutron capture therapy (BNCT) is a binary cancer therapy that involves boron administration and neutron irradiation. The nuclear reaction caused by the interaction of boron atom and neutron produces heavy particles with highly cytocidal effects and destruct tumor cells, which uptake the boron drug. p-Boronophenylalanine (BPA), an amino acid derivative, is used in BNCT. Tumor cells with increased nutrient requirements take up more BPA than normal tissues via the enhanced expression of LAT1, an amino acid transporter. The current study aimed to assess the correlation between the expression of LAT1 and the uptake capacity of BPA using genetically modified LAT1-deficient/enhanced cell lines. We conducted an in vitro study, SCC7 tumor cells wherein LAT1 expression was altered using CRISPR/Cas9 were used to assess BPA uptake capacity. Data from The Cancer Genome Atlas (TCGA) were used to examine the expression status of LAT1 in human tumor tissues, the potential impact of LAT1 expression on cancer prognosis and the potential cancer indications for BPA-based BNCT. We discovered that the strength of LAT1 expression strongly affected the BPA uptake ability of tumor cells. Among the histologic types, squamous cell carcinomas express high levels of LAT1 regardless of the primary tumor site. The higher LAT1 expression in tumors was associated with a higher expression of cell proliferation markers and poorer patient prognosis. Considering that BPA concentrate more in tumors with high LAT1 expression, the results suggest that BNCT is effective for cancers having poor prognosis with higher proliferative potential and nutritional requirements.

LAT1-specific inhibitor ameliorates severe autoimmune arthritis in SKG mouse

L-type amino acid transporter 1 (LAT1, slc7a5) supplies large neutral amino acids to highly proliferative cells. LAT1 is an attractive therapeutic target for treating overactive T cell-mediated immune disorders due to its high expression in activated T cells, but not in resting T cells. Here, we demonstrate that LAT1 plays a crucial role in T helper (Th) 17-mediated autoimmune arthritis in SKG mice, an animal model of human rheumatoid arthritis (RA). Administration of JPH203, a LAT1-specific inhibitor, suppressed mannan-induced joint swelling, synoviocyte proliferation and inflammatory cell infiltration in SKG mice. A diminished metabolic reprogramming, including a decrease in oxidative phosphorylation that regulates Hif-1α expression and subsequent control of glycolysis enzymes, was involved in the downregulation of Th17 differentiation by LAT1 inhibition. Moreover, publicly released database analysis revealed facilitated expression of LAT1 in T cells with cytotoxic features in patients with RA. Our results demonstrate the essential contribution of LAT1 to the development of RA, proposing a potential therapeutic approach targeting amino acid transporters for treating hypersensitive immune diseases.

Functional Characterization of the Solute Carrier LAT-1 (SLC7A5/SLC2A3) in Human Brain Capillary Endothelial Cells with Rapid UPLC-MS/MS Quantification of Intracellular Isotopically Labelled L-Leucine.

The solute carrier L-type amino acid transporter 1 (LAT-1/SLC7A5) is a viable target for drug delivery to the central nervous system (CNS) and tumors due to its high abundance at the blood–brain barrier and in tumor tissue. LAT-1 is only localized on the cell surface as a heterodimer with CD98, which is not required for transporter function. To support future CNS drug-delivery development based on LAT-1 targeting, we established an ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) assay for stable isotopically labeled leucine ([13C6, 15N]-L-leucine), with a dynamic range of 0.1–1000 ng/mL that can be applied for the functional testing of LAT-1 activity when combined with specific inhibitors and, consequently, the LAT-1 inhibition capacity of new compounds. The assay was established in a 96-well format, facilitating high-throughput experiments, and, hence, can support the screening for novel inhibitors. Applicable recommendations of the US Food and Drug Administration and European Medicines Agency for bioanalytical method validation were followed to validate the assay. The assay was applied to investigate the IC50 of two well-known LAT-1 inhibitors on hCMEC/D3 cells: the highly specific LAT-1 inhibitor JPH203, which was also used to demonstrate LAT-1 specific uptake, and the general system L inhibitor BCH. In addition, the [13C6, 15N]-L-leucine uptake was determined on two human brain capillary endothelial cell lines (NKIM-6 and hCMEC/D3), which were characterized for their expressional differences of LAT-1 at the protein and mRNA level and the surface amount of CD98. The IC50 values of the inhibitors were in concordance with previously reported values. Furthermore, the [13C6, 15N]-L-leucine uptake was significantly higher in hCMEC/D3 cells compared to NKIM-6 cells, which correlated with higher expression of LAT-1 and a higher surface amount of CD98. Therefore, the UPLC-MS/MS quantification of ([13C6, 15N]-L-leucine is a feasible strategy for the functional characterization of LAT-1 activity in cells or tissue.