Upregulation of ATF4 mediates the cellular adaptation to pharmacologic inhibition of amino acid transporter LAT1 in pancreatic ductal adenocarcinoma cells.

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.

Inhibition of amino acid transporter LAT1 in cancer cells suppresses G0/G1-S transition by downregulating cyclin D1 via p38 MAPK activation.

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.

Retraction: Nuclear Morphometric Analysis of Leydig Cells of Male Pubertal Rats Exposed In Utero to Di(n-butyl) Phthalate.

[This retracts the article on p. 439 in vol. 26, PMID: 24526819.].

Inhibition of cancer-type amino acid transporter LAT1 suppresses B16-F10 melanoma metastasis in mouse models.

Metastasis is the leading cause of mortality in cancer patients. L-type amino acid transporter 1 (LAT1, SLC7A5) is a Na+-independent neutral amino acid transporter highly expressed in various cancers to support their growth. Although high LAT1 expression is closely associated with cancer metastasis, its role in this process remains unclear. This study aimed to investigate the effect of LAT1 inhibition on cancer metastasis using B16-F10 melanoma mouse models. Our results demonstrated that nanvuranlat (JPH203), a high-affinity LAT1-selective inhibitor, suppressed B16-F10 cell proliferation, migration, and invasion. Similarly, LAT1 knockdown reduced cell proliferation, migration, and invasion. LAT1 inhibitors and LAT1 knockdown diminished B16-F10 lung metastasis in a lung metastasis model. Furthermore, nanvuranlat and LAT1 knockdown suppressed lung, spleen, and lymph node metastasis in an orthotopic metastasis model. We discovered that the LAT1 inhibitor reduced the cell surface expression of integrin αvß3. Our findings revealed that the downregulation of the mTOR signaling pathway, induced by LAT1 inhibitors, decreased the expression of integrin αvß3, contributing to the suppression of metastasis. These results highlight the critical role of LAT1 in cancer metastasis and suggest that LAT1 inhibition may serve as a potential target for anti-metastasis cancer therapy.

Combination effects of amino acid transporter LAT1 inhibitor nanvuranlat and cytotoxic anticancer drug gemcitabine on pancreatic and biliary tract cancer cells.

BACKGROUND: Cytotoxic anticancer drugs widely used in cancer chemotherapy have some limitations, such as the development of side effects and drug resistance. Furthermore, monotherapy is often less effective against heterogeneous cancer tissues. Combination therapies of cytotoxic anticancer drugs with molecularly targeted drugs have been pursued to solve such fundamental problems. Nanvuranlat (JPH203 or KYT-0353), an inhibitor for L-type amino acid transporter 1 (LAT1; SLC7A5), has novel mechanisms of action to suppress the cancer cell proliferation and tumor growth by inhibiting the transport of large neutral amino acids into cancer cells. This study investigated the potential of the combined use of nanvuranlat and cytotoxic anticancer drugs. METHODS: The combination effects of cytotoxic anticancer drugs and nanvuranlat on cell growth were examined by a water-soluble tetrazolium salt assay in two-dimensional cultures of pancreatic and biliary tract cancer cell lines. To elucidate the pharmacological mechanisms underlying the combination of gemcitabine and nanvuranlat, we investigated apoptotic cell death and cell cycle by flow cytometry. The phosphorylation levels of amino acid-related signaling pathways were analyzed by Western blot. Furthermore, growth inhibition was examined in cancer cell spheroids. RESULTS: All the tested seven types of cytotoxic anticancer drugs combined with nanvuranlat significantly inhibited the cell growth of pancreatic cancer MIA PaCa-2 cells compared to their single treatment. Among them, the combined effects of gemcitabine and nanvuranlat were relatively high and confirmed in multiple pancreatic and biliary tract cell lines in two-dimensional cultures. The growth inhibitory effects were suggested to be additive but not synergistic under the tested conditions. Gemcitabine generally induced cell cycle arrest at the S phase and apoptotic cell death, while nanvuranlat induced cell cycle arrest at the G0/G1 phase and affected amino acid-related mTORC1 and GAAC signaling pathways. In combination, each anticancer drug basically exerted its own pharmacological activities, although gemcitabine more strongly influenced the cell cycle than nanvuranlat. The combination effects of growth inhibition were also verified in cancer cell spheroids. CONCLUSIONS: Our study demonstrates the potential of first-in-class LAT1 inhibitor nanvuranlat as a concomitant drug with cytotoxic anticancer drugs, especially gemcitabine, on pancreatic and biliary tract cancers.

LAT1 enables T cell activation under inflammatory conditions.

The aim of this study was to assess the L-type amino acid transporter-1 (LAT1) as a possible therapeutic target for rheumatoid arthritis (RA). Synovial LAT1 expression in RA was monitored by immunohistochemistry and transcriptomic datasets. The contribution of LAT1 to gene expression and immune synapse formation was assessed by RNA-sequencing and total internal reflection fluorescent (TIRF) microscopy, respectively. Mouse models of RA were used to assess the impact of therapeutic targeting of LAT1. LAT1 was strongly expressed by CD4+ T cells in the synovial membrane of people with active RA and the level of expression correlated with levels of ESR and CRP as well as DAS-28 scores. Deletion of LAT1 in murine CD4+ T cells inhibited the development of experimental arthritis and prevented the differentiation of CD4+ T cells expressing IFN-γ and TNF-α, without affecting regulatory T cells. LAT1 deficient CD4+ T cells demonstrated reduced transcription of genes associated with TCR/CD28 signalling, including Akt1, Akt2, Nfatc2, Nfkb1 and Nfkb2. Functional studies using TIRF microscopy revealed a significant impairment of immune synapse formation with reduced recruitment of CD3ζ and phospho-tyrosine signalling molecules in LAT1 deficient CD4+ T cells from the inflamed joints but not the draining lymph nodes of arthritic mice. Finally, it was shown that a small molecule LAT1 inhibitor, currently undergoing clinical trials in man, was highly effective in treating experimental arthritis in mice. It was concluded that LAT1 plays a critical role in activation of pathogenic T cell subsets under inflammatory conditions and represents a promising new therapeutic target for RA.

Engineering amino acid uptake or catabolism promotes CAR T-cell adaption to the tumor environment.

Cancer cells take up amino acids from the extracellular space to drive cell proliferation and viability. Similar mechanisms are applied by immune cells, resulting in the competition between conventional T cells, or indeed chimeric antigen receptor (CAR) T cells and tumor cells, for the limited availability of amino acids within the environment. We demonstrate that T cells can be re-engineered to express SLC7A5 or SLC7A11 transmembrane amino acid transporters alongside CARs. Transporter modifications increase CAR T-cell proliferation under low tryptophan or cystine conditions with no loss of CAR cytotoxicity or increased exhaustion. Transcriptomic and phenotypic analysis reveals that downstream, SLC7A5/SLC7A11-modified CAR T cells upregulate intracellular arginase expression and activity. In turn, we engineer and phenotype a further generation of CAR T cells that express functional arginase 1/arginase 2 enzymes and have enhanced CAR T-cell proliferation and antitumor activity. Thus, CAR T cells can be adapted to the amino acid metabolic microenvironment of cancer, a hitherto recognized but unaddressed barrier for successful CAR T-cell therapy.

Invariant NKT cells metabolically adapt to the acute myeloid leukaemia environment.

Acute myeloid leukaemia (AML) creates an immunosuppressive environment to conventional T cells through Arginase 2 (ARG2)-induced arginine depletion. We identify that AML blasts release the acute phase protein serum amyloid A (SAA), which acts in an autocrine manner to upregulate ARG2 expression and activity, and promote AML blast viability. Following in vitro cross-talk invariant natural killer T (iNKT) cells become activated, upregulate mitochondrial capacity, and release IFN-γ. iNKT retain their ability to proliferate and be activated despite the low arginine AML environment, due to the upregulation of Large Neutral Amino Acid Transporter-1 (LAT-1) and Argininosuccinate Synthetase 1 (ASS)-dependent amino acid pathways, resulting in AML cell death. T cell proliferation is restored in vitro and in vivo. The capacity of iNKT cells to restore antigen-specific T cell immunity was similarly demonstrated against myeloid-derived suppressor cells (MDSCs) in wild-type and Jα18-/- syngeneic lymphoma-bearing models in vivo. Thus, stimulation of iNKT cell activity has the potential as an immunotherapy against AML or as an adjunct to boost antigen-specific T cell immunotherapies in haematological or solid cancers.

Phosphoproteomics revealed cellular signals immediately responding to disruption of cancer amino acid homeostasis induced by inhibition of L-type amino acid transporter 1.

BACKGROUND: Cancer-upregulated L-type amino acid transporter 1 (LAT1; SLC7A5) supplies essential amino acids to cancer cells. LAT1 substrates are not only needed for cancer rapid growth, but involved in cellular signaling. LAT1 has been proposed as a potential target for cancer treatment-its inhibitor, JPH203, is currently in clinical trials and targets biliary tract cancer (BTC). Here, we revealed to what extent LAT1 inhibitor affects intracellular amino acid content and what kind of cellular signals are directly triggered by LAT1 inhibition. METHODS: Liquid chromatography assay combined with o-phthalaldehyde- and 9-fluorenyl-methylchloroformate-based derivatization revealed changes in intracellular amino acid levels induced by LAT1 inhibition with JPH203 treatment in three BTC cell lines. Tandem mass tag-based quantitative phosphoproteomics characterized the effect of JPH203 treatment on BTC cells, and suggested key regulators in LAT1-inhibited cells. We further studied one of the key regulators, CK2 protein kinase, by using Western blot, enzymatic activity assay, and co-immunoprecipitation. We evaluated anticancer effects of combination of JPH203 with CK2 inhibitor using cell growth and would healing assay. RESULTS: JPH203 treatment decreased intracellular levels of LAT1 substrates including essential amino acids of three BTC cell lines, immediately and drastically. We also found levels of some of these amino acids were partially recovered after longer-time treatment. Therefore, we performed phosphoproteomics with short-time JPH203 treatment prior to the cellular compensatory response, and revealed hundreds of differentially phosphorylated sites. Commonly downregulated phosphorylation sites were found on proteins involved in the cell cycle and RNA splicing. Our phosphoproteomics also suggested key regulators immediately responding to LAT1 inhibition. Focusing on one of these regulators, protein kinase CK2, we revealed LAT1 inhibition decreased phosphorylation of CK2 substrate without changing CK2 enzymatic activity. Furthermore, LAT1 inhibition abolished interaction between CK2 and its regulatory protein NOLC1, which suggests regulatory mechanism of CK2 substrate protein specificity controlled by LAT1 inhibition. Moreover, we revealed that the combination of JPH203 with CK2 inhibitor resulted in the enhanced inhibition of proliferation and migration of BTC cells. CONCLUSION: This study provides new perspectives on LAT1-dependent cellular processes and a rationale for therapeutics targeting reprogrammed cancer metabolism.

Pharmacologic inhibition of LAT1 predominantly suppresses transport of large neutral amino acids and downregulates global translation in cancer cells.

L-type amino acid transporter 1 (LAT1; SLC7A5), which preferentially transports large neutral amino acids, is highly upregulated in various cancers. LAT1 supplies cancer cells with amino acids as substrates for enhanced biosynthetic and bioenergetic reactions and stimulates signalling networks involved in the regulation of survival, growth and proliferation. LAT1 inhibitors show anti-cancer effects and a representative compound, JPH203, is under clinical evaluation. However, pharmacological impacts of LAT1 inhibition on the cellular amino acid transport and the translational activity in cancer cells that are conceptually pivotal for its anti-proliferative effect have not been elucidated yet. Here, we demonstrated that JPH203 drastically inhibits the transport of all the large neutral amino acids in pancreatic ductal adenocarcinoma cells. The inhibitory effects of JPH203 were observed even in competition with high concentrations of amino acids in a cell culture medium. The analyses of the nutrient-sensing mTORC1 and GAAC pathways and the protein synthesis activity revealed that JPH203 downregulates the global translation. This study demonstrates a predominant contribution of LAT1 to the transport of large neutral amino acids in cancer cells and the suppression of protein synthesis by JPH203 supposed to underly its broad anti-proliferative effects across various types of cancer cells.

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.

Expression of L-type amino acid transporter 1 is a poor prognostic factor for Non-Hodgkin's lymphoma.

L-type neutral amino acid transporter 1 (LAT1) is a heterodimeric membrane transport protein involved in neutral amino acid transport. LAT1 is highly expressed in various malignant solid tumors and plays an essential role in cell proliferation. However, its role in malignant lymphoma remains unknown. Here, we evaluated LAT1 expression level in tissues from 138 patients with Non-Hodgkin lymphoma (NHL). Overexpression of LAT1 was confirmed in all types of NHL and we found that there is a significant correlation between the level of LAT1 expression and lymphoma grade. The LAT1 expression was higher in aggressive types of lymphomas when compared with static types of lymphomas, suggesting that active tumor proliferation requires nutrient uptake via LAT1. The expression level of LAT1 was inversely correlated with patients' survival span. Furthermore, pharmacological inhibition of LAT1 by a specific inhibitor JPH203 inhibits lymphoma cell growth. In conclusion, our study demonstrated that LAT1 expression can be used as a prognostic marker for patients with NHL and targeting LAT1 by JPH203 can be a novel therapeutic modality for NHL.

L-type amino acid transporter 1 inhibitor suppresses murine Th2 cell-mediated bronchial hyperresponsiveness independently of eosinophil accumulation.

BACKGROUND: The activation of Th2 cells that play a pivotal role in the development of allergic eosinophilic inflammation is regulated by an L-type amino acid transporter (LAT) 1. However, the contribution of LAT1 to the pathogenesis of Th2 cell-mediated airway inflammation has not been investigated. OBJECTIVE: In this study, we investigated the effect of a LAT1 inhibitor, JPH203, on Th2 cell-mediated airway eosinophilic inflammation. METHODS: BALB/c mice were transferred with ovalbumin (OVA)-specific Th2 cell and challenged by corresponding allergen with or without administration of JPH203. Then, the infiltration of inflammatory cells including eosinophils and allergen-specific Th2 cells in the lungs and bronchial hyperresponsiveness (BHR) was assessed. RESULTS: Inflammatory responses in the lungs with massive accumulation of eosinophils and BHR were induced in Th2 cell-transferred mice upon challenge with OVA. The treatment with JPH203 significantly suppressed the allergen-induced BHR but not eosinophil infiltration. The infused Th2 cells were also accumulated in the lungs upon allergen challenge, though the response was not affected by JPH203 treatment. CONCLUSION: JPH203 suppressed Th2 cell-mediated BHR through the mechanisms independently of the lung accumulation of eosinophils and Th2 cells.

Antitumor effect of dimethyl itaconate on thymic carcinoma by targeting LDHA-mTOR axis.

AIMS: Thymic carcinoma is a rare type of cancer without an established standard pharmaceutical treatment. This study investigated the antitumor effect of dimethyl itaconate (DI), a cell-permeable derivative of itaconate, on human thymic carcinoma cell line. MAIN METHODS: Human thymic carcinoma cell line Ty82 was used to evaluate the effect of DI on cell viability. Western blotting and immunohistochemistry were performed to determine the molecular mechanism of antitumor effects of DI on Ty82. KEY FINDINGS: DI suppressed cell growth and promoted apoptosis of Ty82. The suppressive effect of DI on Ty82 was mediated by the downregulation of lactate dehydrogenase A (LDHA), and the subsequent decrease in the activity of mechanistic target of rapamycin (mTOR). DI exhibited synergistic antitumor effects with a specific inhibitor of large neutral amino acid transporter 1 (LAT1), an amino acid transporter currently being investigated as a novel target for cancer therapy. SIGNIFICANCE: Our findings demonstrate that DI is a novel potential strategy for thymic carcinoma treatment.

Prognostic values of L-type amino acid transporter 1 and CD98hc expression in breast cancer.

AIMS: L-type amino acid transporter 1 (LAT1) is a major Na+-independent neutral amino acid transporter, forming a complex with CD98hc. The aim of this study is to investigate the significance of LAT1 and CD98hc in invasive breast cancer. METHODS: LAT1 and CD98hc expression was immunohistochemically assessed in 280 invasive breast cancers and analysed for association with clinicopathological features. RESULTS: High levels of LAT1 and CD98hc were observed in triple-negative breast cancers (TNBCs) possessing negative immunoreactivity with oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, compared with non-TNBCs (NTNBCs), and were associated with lymph-node metastasis and higher nuclear grade. The high-LAT1-expression group showed a poor prognosis in NTNBC and TNBC, however, high-CD98hc-expression group showed a poor prognosis only in NTNBC. LAT1 and CD98hc expression could be the prognostic factors in univariate analyses, but not in multivariate analyses. Further, we found that invasive tumour components showed higher LAT1 and CD98hc expression than non-invasive tumour components. CONCLUSIONS: LAT1 and CD98hc may possess prognostic values in invasive breast cancer. LAT1 may be linked with cancer cell activities and disease progression in breast cancer.

Proteomics and phosphoproteomics reveal key regulators associated with cytostatic effect of amino acid transporter LAT1 inhibitor.

L-type amino acid transporter 1 (LAT1) is highly expressed in various cancers and plays important roles not only in the amino acid uptake necessary for cancer growth but also in cellular signaling. Recent research studies have reported anticancer effects of LAT1 inhibitors and demonstrated their potential for cancer therapy. Here, we characterized the proteome and phosphoproteome in LAT1-inhibited cancer cells. We used JPH203, a selective LAT1 inhibitor, and performed tandem mass tag-based quantitative proteomics and phosphoproteomics on four biliary tract cancer cell lines sensitive to JPH203. Our analysis identified hundreds to thousands of differentially expressed proteins and phosphorylated sites, demonstrating the broad influence of LAT1 inhibition. Our findings showed various functional pathways altered by LAT1 inhibition, and provided possible regulators and key kinases in LAT1-inhibited cells. Comparison of these changes among cell lines provides insights into general pathways and regulators associated with LAT1 inhibition and particularly suggests the importance of cell cycle-related pathways and kinases. Moreover, we evaluated the anticancer effects of the combinations of JPH203 with cell cycle-related kinase inhibitors and demonstrated their potential for cancer therapy. This is the first study providing the proteome-wide scope of both protein expression and phosphorylation signaling perturbed by LAT1 inhibition in cancer cells.

Amino acid transporter LAT1 in tumor-associated vascular endothelium promotes angiogenesis by regulating cell proliferation and VEGF-A-dependent mTORC1 activation.

BACKGROUND: Tumor angiogenesis is regarded as a rational anti-cancer target. The efficacy and indications of anti-angiogenic therapies in clinical practice, however, are relatively limited. Therefore, there still exists a demand for revealing the distinct characteristics of tumor endothelium that is crucial for the pathological angiogenesis. L-type amino acid transporter 1 (LAT1) is well known to be highly and broadly upregulated in tumor cells to support their growth and proliferation. In this study, we aimed to establish the upregulation of LAT1 as a novel general characteristic of tumor-associated endothelial cells as well, and to explore the functional relevance in tumor angiogenesis. METHODS: Expression of LAT1 in tumor-associated endothelial cells was immunohistologically investigated in human pancreatic ductal adenocarcinoma (PDA) and xenograft- and syngeneic mouse tumor models. The effects of pharmacological and genetic ablation of endothelial LAT1 were examined in aortic ring assay, Matrigel plug assay, and mouse tumor models. The effects of LAT1 inhibitors and gene knockdown on cell proliferation, regulation of translation, as well as on the VEGF-A-dependent angiogenic processes and intracellular signaling were investigated in in vitro by using human umbilical vein endothelial cells. RESULTS: LAT1 was highly expressed in vascular endothelial cells of human PDA but not in normal pancreas. Similarly, high endothelial LAT1 expression was observed in mouse tumor models. The angiogenesis in ex/in vivo assays was suppressed by abrogating the function or expression of LAT1. Tumor growth in mice was significantly impaired through the inhibition of angiogenesis by targeting endothelial LAT1. LAT1-mediated amino acid transport was fundamental to support endothelial cell proliferation and translation initiation in vitro. Furthermore, LAT1 was required for the VEGF-A-dependent migration, invasion, tube formation, and activation of mTORC1, suggesting a novel cross-talk between pro-angiogenic signaling and nutrient-sensing in endothelial cells. CONCLUSIONS: These results demonstrate that the endothelial LAT1 is a novel key player in tumor angiogenesis, which regulates proliferation, translation, and pro-angiogenic VEGF-A signaling. This study furthermore indicates a new insight into the dual functioning of LAT1 in tumor progression both in tumor cells and stromal endothelium. Therapeutic inhibition of LAT1 may offer an ideal option to potentiate anti-angiogenic therapies.

Biomarker Analyses in Patients With Advanced Solid Tumors Treated With the LAT1 Inhibitor JPH203.

BACKGROUND/AIM: Amino acids are among the most important nutrients for supplying energy and building protein blocks in cancers. L-type amino acid transporter (LAT) 1 is known to play a critical role in cancer growth. We have completed the first-in-human phase I study using the LAT1-specific inhibitor JPH203. PATIENTS AND METHODS: We evaluated plasma free amino acids (PFAAs), body mass index (BMI), and efficacy of JPH203 in patients enrolled in the phase I study. RESULTS: LAT1-substrate PFAAs and branched chain amino acids (BCAAs) were higher in patients with biliary tract cancer (BTC) than in those with other cancers. High inhibition of uptake of LAT1-substrate PFAAs was associated with survival. BMI of more than the median was associated with disease control and survival. BCAAs tended to be associated with BMI. CONCLUSION: BCAAs and BMI are useful predictors of the efficacy of JPH203, which shows promising activity against BTC.

Positive correlation of expression of L-type amino-acid transporter 1 with colorectal tumor progression and prognosis: Higher expression in sporadic colorectal tumors compared with ulcerative colitis-associated neoplasia.

The role of L-type amino-acid transporter 1 (LAT1), an oncofetal protein, in tumor progression is not well known, although it is important for the survival and proliferation of cancer cells. LAT1 expression was immunohistochemically analyzed and compared in sporadic (conventional) colorectal tumors and ulcerative colitis (UC)-associated neoplasia development and progression. LAT1 expression showed a significant stepwise increase in the order: conventional low-grade tubular adenoma, high-grade tubular adenoma, and invasive adenocarcinoma. Similarly, the same increasing trend in LAT1 expression was found in UC-associated low-grade dysplasia, high-grade dysplasia, and adenocarcinoma, whereas expression was significantly lower compared with that in an adenoma-adenocarcinoma series. LAT1 expression was predominant in the upper half of mucosal lesions in low-grade adenoma. This localized difference in LAT1 expression between the upper and lower halves of mucosal lesions disappeared in conventional high-grade adenoma and adenocarcinoma. LAT1 expression in the colorectal mucosa was significantly increased in the order: nontumor mucosa, quiescent phase of UC, and active phase of UC. Considering the histological pattern of Ki-67 labeling, LAT1 expression appeared partly related to cell proliferation, but this was not significant. In relation to the prognosis of patients with sporadic phase IV colorectal adenocarcinoma, this was significantly poorer in the group with high LAT1 expression compared with that with low LAT1 expression. This suggests LAT1 expression may be used as a companion biomarker for anti-cancer therapy targeting the LAT1 molecule in colorectal cancers.