Search Results (86)

The plant NAC (NAM, ATAF1/2, and CUC2) transcription factor family plays an important regulatory role in stress response. In this study, we analyzed the rice transcription factor OsNAC113 and elucidated its tissue-specific characteristics and stress response regulatory mechanisms. qRT-PCR results showed that under laboratory-simulated drought, high salt, temperature stress, and hormone treatments, such as abscisic acid (ABA) and gibberellic acid (GA₃), the expression level of OsNAC113 significantly changed, indicating that OsNAC113 responds to various stress conditions. Targeted creation of the rice (Oryza sativa L. spp. japonica) OsNAC113 (LOC_os08g10080.1) mutant based on the CRISPR-Cas9 genome editing strategy revealed its response to salt stress (200 mM). The growth status and survival rate of the mutant under high-salt stress were significantly higher than those of the wild type. Testing showed that the mutant exhibited increased relative water, chlorophyll, and soluble sugar contents under salt stress than the wild type. The malondialdehyde content in the mutant was lower, and the activities of superoxide dismutase, peroxidase, and catalase were higher than those in the wild type, indicating that the mutant with functional loss caused by knocking out OsNAC113 had a significantly enhanced tolerance to salt treatment. Using RNA-seq to detect genome-wide changes in OsNAC113 mutant materials under stress, KEGG annotation showed that knocking out OsNAC113 resulted in regulatory changes in “plant hormone signaling pathway” and “MAPK signaling pathway,” and GO and KEGG annotations showed significant changes in “amino acid transport and metabolism,” “carbohydrate transport and metabolism,” “lipid transport and metabolism,” and “replication, recombination, and repair.” OsNAC113 may be involved in the response to salt stress by regulating these signaling pathways. Using comparative metabolomic analysis, we further elucidated the function of OsNAC113 in physiological metabolic pathways. The knockout of OsNAC113 resulted in changes in various important metabolic pathways in plants, including flavonoid biosynthesis and ABC transporters. Therefore, it is suggested that OsNAC113 is involved in these metabolic processes and affects their regulation in high-salt environments. These results provide a theoretical foundation and reliable material for the molecular breeding of rice. Full article

Introduction: Breast cancer is a heterogeneous malignancy influenced by diverse molecular profiles. The L-type amino acid transporter 1 (LAT1), encoded by the SLC7A5 gene, plays a key role in tumor metabolism, growth, and angiogenesis. Through its role in amino acid transport and activation of the mTORC1 signaling pathway, LAT1 has emerged as a potential therapeutic target. Objective: To evaluate SLC7A5/LAT1 expression and its association with clinicopathological parameters and molecular subtypes of invasive carcinoma of no special type (NST) in a Pakistani cohort. Methods: Eighty-three patients who underwent mastectomy or modified radical mastectomy for histologically confirmed primary invasive carcinoma of no special type were included. Immunohistochemistry was used to assess SLC7A5/LAT1 expression. Associations with clinicopathological features and molecular groups were analyzed using the Chi-square test. Results: The mean age of SLC7A5-positive patients were 48.4 ± 10.8 years. Overall, 24.1% of patients demonstrated SLC7A5 positivity. Although SLC7A5 expression was more frequent in cases categorized as having moderate or poor prognosis based on the Nottingham Prognostic Index (NPI), this trend was not statistically significant. Similarly, no significant associations were observed between SLC7A5 expression and other clinicopathological or molecular variables. Conclusions:SLC7A5/LAT1 expression was identified in approximately one-quarter of invasive breast carcinoma cases. Its expression appeared more common in tumors with poorer NPI categories, but without statistically verified associations. These findings suggest that SLC7A5 may act independently of conventional clinicopathological parameters. Larger, longitudinal studies with survival follow-up are required to clarify its prognostic and therapeutic significance. Full article

Malignant bone and soft tissue tumors are often resistant to conventional treatment, and treatment options for unresectable and metastatic cases are limited. L-type amino acid transporter 1 (LAT1) is overexpressed in several malignancies, including sarcomas, making it an attractive target for targeted alpha therapy. In this study, we investigated the therapeutic efficacy of LAT1-targeted alpha therapy using a novel modified 3-astatin-211 Astato-α-methyl-L-tyrosine (²¹¹At-AAMT) for bone and soft tissue sarcomas. LAT1 expression and the specificity of LAT1-mediated uptake of ²¹¹At-AAMT were evaluated in bone and soft tissue sarcoma cell lines. Antiproliferative effects were assessed using cell viability and colony formation assays. DNA damage was assessed using immunostaining with phosphorylated histone γH2AX. In vivo efficacy of ²¹¹At-AAMT, determined using xenograft mouse models, was compared with that of doxorubicin. LAT1 was highly expressed in all cell lines, especially MP-CCS-SY and MG-63 cells. ²¹¹At-AAMT uptake was LAT1-dependent and significant in all cell lines. It inhibited cell proliferation in a dose-dependent manner, comparable to that of doxorubicin. In xenograft models, a single administration of ²¹¹At-AAMT significantly inhibited tumor growth without systemic toxicity, whereas doxorubicin caused weight loss. Histopathological analysis showed reduced cell density, inhibited proliferation, and extensive DNA damage in tumors treated with ²¹¹At-AAMT, whereas LAT1 expression was maintained in residual tumor tissues. LAT1-targeted alpha therapy with ²¹¹At-AAMT demonstrated antitumor efficacy comparable to that of first-line chemotherapy for osteosarcoma and soft tissue sarcoma. Sustained LAT1 expression suggests the potential for repeated or combination treatments, highlighting its promise as a novel therapy for advanced, treatment-resistant sarcomas. Full article

Weeds present a pervasive challenge in agricultural fields. The integration of herbicide-resistant crops with chemical weed management offers an effective solution for sustainable weed control while reducing labor inputs, particularly in large-scale intensive farming systems. Consequently, the development of herbicide-resistant cultivars has emerged as an urgent priority. In this study, we found that the G311E mutant gene of Arabidopsis MATE (multidrug and toxic compound extrusion) family transporter DTX6, designated DTX6m, confers robust resistance to bipyridyl herbicides paraquat and diquat in rice. DTX6m-overexpression lines exhibited marked resistance to these two herbicides, tolerating diquat concentrations up to 5 g/L, which is five-fold higher than the recommended field application dosage. Agronomic assessments demonstrated that grain yields of DTX6m-overexpressing plants were statistically equivalent to those of wild-type plants. Moreover, the plants displayed beneficial phenotypic changes, such as accelerated flowering and a slight reduction in height. Seed morphometric analysis indicated that in comparison with the wild-type control, DTX6m-transgenic lines exhibited altered grain dimensions while maintaining consistent 1000-grain weight. Nutritional assays further demonstrated that DTX6m increased the levels of free amino acids in seeds, while normal protein and starch contents were retained. Collectively, these results establish that DTX6m effectively boosts rice resistance to paraquat and diquat, validating DTX6m as a candidate gene for engineering plant herbicide resistance and also implying a potential role for DTX6m in amino acid homeostasis in plants. Full article

L-3-[¹⁸F]-fluoro-α-methyl tyrosine ([¹⁸F]FAMT) is an amino acid positron emission tomography (PET) tracer with high specificity for malignant tumors through its selective transport via L-type amino acid transporter (LAT) 1. Although extensively studied for its diagnostic performance, a comprehensive review of its molecular and clinical characteristics remains lacking. A systematic literature review (1997–2025) was conducted using PubMed and Web of Science, with keywords including “L-3-[¹⁸F]-fluoro-α-methyl tyrosine”, “[¹⁸F]FAMT”, “amino acid PET”, and “tumor imaging”. The review covered aspects of synthesis, structural properties, pharmacokinetics, and clinical applications. Notably, while research on [¹⁸F]FAMT has declined significantly in recent years, [¹⁸F]FAMT PET demonstrates superior specificity to [¹⁸F]FDG PET in distinguishing malignancies from inflammatory lesions and offers distinct advantages in lung, esophageal, and oral cancers, though with slightly lower sensitivity. Its key features include tumor-specific uptake patterns, rapid blood clearance, and a significant correlation between its uptake levels and both LAT1 expression and tumor proliferation. In conclusion, [¹⁸F]FAMT is a promising PET tracer with notable advantages in tumor imaging, particularly due to its LAT1 selectivity and favorable pharmacokinetics. Despite challenges in production, these characteristics underscore its clinical value in cancers requiring precise imaging. Future research should focus on optimizing synthesis, expanding clinical validation, and exploring theranostic applications. Full article

Background: Monoclonal antibodies against the sodium-dependent phosphate transporter NaPi2b (SLC34A2) represent a promising approach in the treatment of ovarian and lung cancer. Of particular interest is the potential cancer-specific MX35 epitope of NaPi2b, as it serves as a target for monoclonal antibodies studied at various stages of preclinical and clinical trials. However, variations in the NaPi2b protein structure may limit the efficacy of therapeutic antibodies by affecting the accessibility of the MX35 epitope. Methods: An in silico analysis was performed using data from 101,562 tumor samples. Genomic DNA sequencing was conducted on blood samples from patients with ovarian carcinoma, breast cancer, and renal carcinoma to access the frequency of germline mutations in the SLC34A2 gene region encoding the MX35 epitope. To assess the impact of the selected mutation, we generated a model cell line through site-directed mutagenesis carrying the mutant NaPi2b variant. Results: Using in silico analysis, we identified 17 unique variants in the SLC34A2 gene leading to amino acid substitutions within the MX35 epitope of the NaPi2b. Among these, the most prevalent mutation, c.989C>T, resulting in p.T330M substitution, was detected in 5 out of 64 patients through genomic DNA sequencing. Using site-directed mutagenesis, we created the OVCAR-8/NaPi2b^p.T330M model cell line. L3 (28/1) monoclonal antibodies specific to the MX35 epitope failed to recognize the mutant NaPi2b^p.T330M variant compared to the wild-type of the NaPi2b in both Western blot and confocal microscopy experiments. Conclusions: The obtained data may serve as a basis for predicting the efficacy of monoclonal antibody-based targeted therapy binding to the MX35 epitope of NaPi2b in the treatment of oncological diseases. Full article

A novel, strictly aerobic, non-motile, and pink-pigmented bacterium, designated 7Alg 153^T, was isolated from the Pacific green alga Cladophora stimpsonii. Strain 7Alg 153^T was able to grow at 4–32 °C in the presence of 1.5–4% NaCl and hydrolyze L-tyrosine, gelatin, aesculin, Tweens 20, 40, and 80 and urea, as well as produce catalase, oxidase, and nitrate reductase. The novel strain 7Alg 153^T showed the highest similarity of 96.75% with Pseudaestuariivita rosea H15^T, followed by Thalassobius litorarius MME-075^T (96.60%), Thalassobius mangrovi GS-10^T (96.53%), Tritonibacter litoralis SM1979^T (96.45%), and Marivita cryptomonadis CL-SK44^T (96.38%), indicating that it belongs to the family Roseobacteraceae, the order Rhodobacteales, the class Alphaproteobacteria, and the phylum Pseudomonadota. The respiratory ubiquinone was Q-10. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids, and one unidentified lipid. The predominant cellular fatty acids (>5%) were C_18:1 ω7c, C_16:0, C_18:0, and 11-methyl C_18:1 ω7c. The 7Alg 153^T genome is composed of a single circular chromosome of 3,786,800 bp and two circular plasmids of 53,157 bp and 37,459 bp, respectively. Pan-genome analysis showed that the 7Alg 153^T genome contains 33 genus-specific clusters spanning 92 genes. The COG20-annotated singletons were more often related to signal transduction mechanisms, cell membrane biogenesis, transcription, and transport, and the metabolism of amino acids. The complete photosynthetic gene cluster (PGC) for aerobic anoxygenic photosynthesis (AAP) was found on a 53 kb plasmid. Based on the phylogenetic evidence and phenotypic and chemotaxonomic characteristics, the novel isolate represents a novel genus and species within the family Roseobacteraceae, for which the name Algirhabdus cladophorae gen. nov., sp. nov. is proposed. The type strain is 7Alg 153^T (=KCTC 72606^T = KMM 6494^T). Full article

Porphyromonas gingivalis is a key pathogen in periodontitis. Its outer membrane contains the RagAB transport complex, which has been implicated in protein uptake, essential for a proteolytic species. RagA is a 22-stranded β-barrel, and RagB is the corresponding 4-TPR lid, together forming a TonB-dependent system acting as a “pedal bin”. Four different alleles were observed, of which ragAB-1 is more virulent than the others. Our aim was to map ragAB in 129 strains of P. gingivalis and related species available in our collection, supported by a newly introduced universal PCR for amplification/sequencing of all four ragA variants and to find reasons for the differences in virulence and/or fitness. Regarding the PCR method, by pairing established Long-PCR primers with our newly designed sequencing primers (ragA-F0, -F1, -R2, -R2a, -R4), it was possible to amplify and sequence all four ragA variants. The same was not possible for ragB due to high heterogeneity. The mapping allowed us to type all strains into ragAB-1-4. For each type, some strains (of mainly animal origin such as Porphyromonas gulae) with slightly different amino acid sequences were identified (designated ragAB-1a to -4a). In terms of function, the transfer of recently discovered SusCD information to the similar RagAB complex provided new insights. Substrate specificity as well as length of pedal could be the route to differential virulence (survival rate, fitness) as Rag-1 (closer related to Rag-3/4) and Rag-2 were found to be massively different here. In general, substrate–ligand-binding sites seem to be quite variable with the exception of Rag-1, probably indicating nutritional preferences. In addition, an insertion (8 aa long) found in loop L7 throughout RagA-2 could not only affect the dynamics of lid opening/closing but might also alter the associated substrate throughput rate. Full article

Phenylalanine (Phe) is a potentially limiting amino acid for lactating cows. The mechanism by which Phe regulates milk protein synthesis remains unclear. The present study elucidates the mechanisms by which phenylalanine affects milk protein synthesis, amino acid utilization, and related signaling pathways in bovine mammary epithelial cells (BMECs). The BMECs were treated with five concentrations (0, 0.22, 0.44, 0.88, 1.76 mM, and serum free). Rapamycin inhibitors and RNA interference (RNAi) were used to inhibit the phosphorylation of the mammalian target of rapamycin (mTOR) signaling pathway and the expression of relevant amino acid transporters, respectively. The results showed that 4×Phe (0.88 mM) significantly increased (p < 0.05) both the mRNA and protein expression of α-casein (CSN1S1), β-casein (CSN2), and κ-casein (CSN3), as well as L-type amino acid transporter-1 (LAT1) mRNA expression. Protein expression and modification assays of mTOR-related proteins showed that 4×Phe could increase (p < 0.05) the expression of α-casein and eukaryotic initiation factor 4E-binding protein-1 (4EBP1) and tended to increase the expression of ribosomal protein S6 protein kinase (S6K1, p = 0.054). The general control nonderepressible 2 (GCN2) signaling pathway factor, eukaryotic initiation factor 2 (eIF2α), was downregulated by 4×Phe treatment (p < 0.05). The rapamycin inhibition test showed that Phe regulated casein synthesis via the mTOR signaling pathway. RNAi experiments showed that LAT1 mediated the entry of Phe into cells. Moreover, 4×Phe treatment tended to decrease (0.05 < p < 0.10) the consumption of valine, leucine, histidine, tyrosine, cysteine, alanine, asparagine, and serine in the medium. Collectively, phenylalanine enhanced α-casein synthesis by regulating the phosphorylation of 4EBP1 and eIF2α and promoting the formation of the mTOR-centered casein translation initiation complex. Full article

We investigated nuclear medicine therapeutics targeting the L-type amino acid transporter 1 (LAT1). We previously reported that a nuclear medicine therapeutic drug using astatine 211 (²¹¹At), an alpha-emitting nuclide that can be produced in an accelerator and targets LAT1 as a molecular target, is effective. The seed compound was 3-[²¹¹At] Astato-α-methyl-L-tyrosine (²¹¹At-AAMT-OH-L). We used a unique labeling method. By changing the OH group of phenol to a methyl group, retention was successfully increased. It was also found that the amount of the L-isomer taken up by the D-isomer and L-isomer was clearly higher, and the L-isomer was superior as a therapeutic drug. Compounds in which the methyl group was replaced with an ethyl or propyl group were also examined, but their retention did not increase significantly. In fact, we observed increased non-specific accumulation and dynamics, suggesting that labeling may be off. In addition, ²¹¹At-AAMT-O-Me-L, which has a simple structure, was clearly superior in terms of uptake speed for several candidate compounds. As a result, we were able to develop a compound that can be easily labeled, has high specific radioactivity, is stable, and has a strong therapeutic effect. Full article

Amino acid transporters play pivotal roles in cancer biology, including in urological cancers. Among them, L-type amino acid transporter 1 (LAT1), alanine-serine-cysteine transporter 2 (ASCT2), and cystine-glutamate transporter (xCT) have garnered significant attention due to their involvement in various aspects of tumor progression and response to therapy. This review focuses on elucidating the regulation and functions of these amino acid transporters in urological cancers, including prostate, bladder, and renal cancers. Understanding the intricate regulatory mechanisms governing these amino acid transporters is essential for developing effective therapeutic strategies. Furthermore, exploring their interactions with signaling pathways and microenvironmental cues in the context of urological cancers may uncover novel therapeutic vulnerabilities. This comprehensive overview highlights the importance of amino acid transporters, particularly LAT1, ASCT2, and xCT, in urological cancers and underscores the potential of their inhibitors as therapeutic targets for improving patient outcomes. Full article

Branched-chain amino acids (BCAAs) are essential for muscle protein synthesis and are widely acknowledged for mitigating sarcopenia. Oligonol^® (Olg), a low-molecular-weight polyphenol from Litchi chinensis, has also been found to attenuate sarcopenia by improving mitochondrial quality and positive protein turnover. This study aims to investigate the effect of Olg on BCAA-stimulated protein synthesis in sarcopenia. In sarcopenic C57BL/6 mice and senescence-accelerated mouse-prone 8 (SAMP8) mice, BCAAs were significantly decreased in skeletal muscle but increased in blood serum. Furthermore, the expressions of membrane L-type amino acid transporter 1 (LAT1) and branched-chain amino acid transaminase 2 (BCAT2) in skeletal muscle were lower in aged mice than in young mice. The administration of Olg for 8 weeks significantly increased the expressions of membrane LAT1 and BCAT2 in the skeletal muscle when compared with non-treated SAMP8 mice. We further found that BCAA deprivation via LAT1-siRNA in C2C12 myotubes inhibited the signaling of protein synthesis and facilitated ubiquitination degradation of BCAT2. In C2C12 cells mimicking sarcopenia, Olg combined with BCAA supplementation enhanced mTOR/p70S6K activity more than BCAA alone. However, blocked LAT1 by JPH203 reversed the synergistic effect of the combination of Olg and BCAAs. Taken together, changes in LAT1 and BCAT2 during aging profoundly alter BCAA availability and nutrient signaling in aged mice. Olg increases BCAA-stimulated protein synthesis via modulating BCAA transportation and BCAA catabolism. Combining Olg and BCAAs may be a useful nutritional strategy for alleviating sarcopenia. Full article

Glioblastoma, a fatal brain cancer with limited treatments and poor prognosis, could benefit from targeting the L-type amino acid transporter I (LAT1). LAT1 is essential for cancer cells to acquire necessary amino acids. Tetrahydrocurcumin (THC), a key curcumin derivative, shows potential for glioblastoma treatment. However, its effectiveness is hindered by poor physicochemical and pharmacokinetic properties. Therefore, this study aims to improve the therapeutic efficacy of THC against glioblastoma by chemically modifying it to target LAT1. A novel series of THC-amino acid conjugates were synthesized by conjugating five amino acids: glycine, leucine, isoleucine, and phenylalanine to THC via carbamate bonds. The therapeutic efficacy of THC-amino acid conjugates was further examined in C6 glioma cells, including the role of LAT1 in their therapeutic effects. Among the conjugates tested, THC conjugated with two phenylalanines (THC-di-Phe) showed remarkably higher cytotoxicity against C6 glioma cells (35.8 μM) compared to THC alone (110.7 μM). THC-di-Phe induced cellular death via necrosis and apoptosis, outperforming THC. Additionally, THC-di-Phe inhibited C6 cell proliferation and migration more effectively than THC. Co-incubation of THC-di-Phe with the LAT1 inhibitor 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) further increased cellular death. THC-di-Phe also significantly inhibited the P70SK/S6 pathway, regulated by LAT1 inhibitors, more effectively than THC and displayed a similar binding mode with both JX-075 and BCH to the active site of LAT1. Findings suggest the potential role of THC-di-Phe as a LAT1 inhibitor and provide novel insight into its use as a potent antitumor agent in glioma with increased therapeutic efficacy. Full article

Background: Methionine (Met) is a popular nutritional supplement in humans and animals. It is routinely supplemented to pigs as L-Met, DL-Met, or DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA). Methods: We investigated the effect of these Met supplements on jejunal amino acid (AA) transport in male castrated Piétrain × Danbred pigs, also including a non-supplemented group. The mucosal-to-serosal flux of ten [¹⁴C]-labeled AAs (L-glutamine, glycine, L-leucine, L-lysine, L-Met, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine) was investigated at two concentrations (50 µM and 5 mM). Inhibition of apical uptake by mucosal L-Met was also measured for these AAs. The intestinal expression of apical AA transporters, angiotensin-converting enzyme II and inflammation-related genes were compared with those of a previous study. Results: Except for tryptophan and lysine at 5 mM, all AA fluxes were Na⁺-dependent (p ≤ 0.05), and the uptake of most AAs, except glycine and lysine, was inhibited by L-Met (p < 0.001). A correlation network existed between Na⁺-dependent fluxes of most AAs (except tryptophan and partly glycine). We observed the upregulation of B⁰AT1 (SLC6A19) (p < 0.001), the downregulation of ATB^0,+ (SLC6A14) (p < 0.001) and a lower expression of CASP1, IL1β, IL8, TGFβ and TNFα in the present vs. the previous study (p < 0.001). Conclusions: The correlating AAs likely share the same Na⁺-dependent transporter(s). A varying effect of the Met supplement type on AA transport in the two studies might be related to a different level of supplementation or a different inflammatory status of the small intestine. Full article

Camellia luteoflora is a rare and endangered plant endemic to China. It has high ornamental and potential economic and medicinal value, and is an important germplasm resource of Camellia. To understand the distributions and differences in metabolites from different parts of C. luteoflora, in this study, we used liquid chromatography–tandem mass spectrometry (LC–MS/MS) to examine the types and contents of chemical constituents in five organs of C. luteoflora: roots, stems, leaves, flowers, and fruits. The results showed that a total of 815 metabolites were identified in the five organs and were classified into 18 main categories, including terpenoids (17.1%), amino acids (10.4%), flavonoids (10.3%), sugars and alcohols (9.8%), organic acids (9.0%), lipids (7.1%), polyphenols (4.8%), alkaloids (4.8%), etc. A total of 684 differentially expressed metabolites (DEMs) in five organs were obtained and annotated into 217 KEGG metabolic pathways, among which metabolic pathways, ABC transporters, the biosynthesis of cofactors, and the biosynthesis of amino acids were significantly enriched. In DEMs, flowers are rich in flavonoids, polyphenols, organic acids, and steroids; fruits are rich in amino acids, alkaloids, vitamins, and xanthones; stems are rich in lignans; and leaves have the highest relative content of phenylpropanoids, ketoaldehydic acids, quinones, sugars and alcohols, terpenoids, coumarins, lipids, and others; meanwhile, the metabolite content is lower in roots. Among the dominant DEMs, 58 were in roots, including arachidonic acid, lucidone, isoliquiritigenin, etc.; 75 were in flowers, including mannose, shikimic acid, d-gluconic acid, kaempferol, etc.; 45 were in the fruit, including pterostilbene, l-ascorbic acid, riboflavin, etc.; 27 were in the stems, including salicylic acid, d-(-)-quinic acid, mannitol, (-)-catechin gallate, etc.; there was a maximum number of 119 dominant metabolites in the leaves, including oleanolic acid, l-glucose, d-arabitol, eugenol, etc. In sum, the rich chemical composition of C. luteoflora and the significant differences in the relative contents of metabolites in different organs will provide theoretical references for the study of tea, flower tea, edible oil, nutraceuticals, and the medicinal components of C. luteoflora. Full article