LLGL2 rescues nutrient stress by promoting leucine uptake in ER+ breast cancer

Amino acid transporters within the solute carrier superfamily: Underappreciated proteins and novel opportunities for cancer therapy

BACKGROUND

Solute carrier (SLC) transporters, a diverse family of membrane proteins, are instrumental in orchestrating the intake and efflux of nutrients including amino acids, vitamins, ions, nutrients, etc, across cell membranes. This dynamic process is critical for sustaining the metabolic demands of cancer cells, promoting their survival, proliferation, and adaptation to the tumor microenvironment (TME). Amino acids are fundamental building blocks of cells and play essential roles in protein synthesis, nutrient sensing, and oncogenic signaling pathways. As key transporters of amino acids, SLCs have emerged as crucial players in maintaining cellular amino acid homeostasis, and their dysregulation is implicated in various cancer types. Thus, understanding the intricate connections between amino acids, SLCs, and cancer is pivotal for unraveling novel therapeutic targets and strategies.

SCOPE OF REVIEW

In this review, we delve into the significant impact of amino acid carriers of the SLCs family on the growth and progression of cancer and explore the current state of knowledge in this field, shedding light on the molecular mechanisms that underlie these relationships and highlighting potential avenues for future research and clinical interventions.

MAJOR CONCLUSIONS

Amino acids transportation by SLCs plays a critical role in tumor progression. However, some studies revealed the tumor suppressor function of SLCs. Although several studies evaluated the function of SLC7A11 and SLC1A5, the role of some SLC proteins in cancer is not studied well. To exert their functions, SLCs mediate metabolic rewiring, regulate the maintenance of redox balance, affect main oncogenic pathways, regulate amino acids bioavailability within the TME, and alter the sensitivity of cancer cells to therapeutics. However, different therapeutic methods that prevent the function of SLCs were able to inhibit tumor progression. This comprehensive review provides insights into a rapidly evolving area of cancer biology by focusing on amino acids and their transporters within the SLC superfamily.

Novel role of LLGL2 silencing in autophagy: reversing epithelial-mesenchymal transition in prostate cancer

PURPOSE

Prostate cancer (PCa) is a major urological disease that is associated with significant morbidity and mortality in men. LLGL2 is the mammalian homolog of Lgl. It acts as a tumor suppressor in breast and hepatic cancer. However, the role of LLGL2 and the underlying mechanisms in PCa have not yet been elucidated. Here, we investigate the role of LLGL2 in the regulation of epithelial-mesenchymal transition (EMT) in PCa through autophagy in vitro and in vivo.

METHODS

PC3 cells were transfected with siLLGL2 or plasmid LLGL2 and autophagy was examined. Invasion, migration, and wound healing were assessed in PC3 cells under autophagy regulation. Tumor growth was evaluated using a shLLGL2 xenograft mouse model.

RESULTS

In patients with PCa, LLGL2 levels were higher with defective autophagy and increased EMT. Our results showed that the knockdown of LLGL2 induced autophagy flux by upregulating Vps34 and ATG14L. LLGL2 knockdown inhibits EMT by upregulating E-cadherin and downregulating fibronectin and α-SMA. The pharmacological activation of autophagy by rapamycin suppressed EMT, and these effects were reversed by 3-methyladenine treatment. Interestingly, in a shLLGL2 xenograft mouse model, tumor size and EMT were decreased, which were improved by autophagy induction and worsened by autophagy inhibition.

CONCLUSION

Defective expression of LLGL2 leads to attenuation of EMT due to the upregulation of autophagy flux in PCa. Our results suggest that LLGL2 is a novel target for alleviating PCa via the regulation of autophagy.

Identification of SLC12A8 as a valuable prognostic biomarker and immunotherapeutic target by comprehensive pan-cancer analysis

Solute carrier family 12 member 8 (SLC12A8) is a nicotinamide mononucleotide transporter. Despite emerging evidence supporting its potential involvement in oncogenesis, a systematic pan-cancer analysis of SLC12A8 has not been performed. Thus, this research aimed to explore the prognostic implications of SLC12A8 and assess its possible immune-related functions across 33 different tumor types. And multiple datasets were retrieved from the databases of TCGA, GTEx, Broad Institute CCLE, TISCH, HPA, and GDSC2. After this data acquisition, bioinformatics analyses were conducted to assess the potential involvement of SLC12A8 in cancer pathogenesis. These analyses focused on examining the relationship between SLC12A8 and prognosis, drug sensitivity, chemotherapy response, immune checkpoints (ICPs), immune cell infiltration, and immunotherapy efficacy across various tumor types. Furthermore, experimental methods such as EdU assay, wound healing assay, and transwell assay were conducted to evaluate the cell proliferative and invasive abilities. Finally, the data analysis demonstrated that SLC12A8 was differentially expressed and predicted unfavorable survival outcomes in the majority of the tumor types in the TCGA dataset. Furthermore, a notable upregulation in the expression of SLC12A8 mRNA and protein was observed in cancer tissues compared to normal tissues. Additionally, the SLC12A8 levels demonstrated a strong association with ICPs, chemokines, immune-activating genes, immune-suppressive genes, chemokine receptors, chemotherapy response, and immunotherapy efficacy. In vitro experiments substantiated that knockdown of SLC12A8 restricted the malignant phenotypes of MDA-MB-231 and BT-549 cells. So SLC12A8 holds promise as a cancer biomarker with the capacity to interact with other ICPs to synergistically regulate the immune microenvironment. Thus, the identification of SLC12A8 contributes to the development of novel therapeutic strategies for enhancing the efficacy of immunotherapy.

The role of amino acid metabolism in autoimmune hepatitis

Autoimmune hepatitis (AIH) is an inflammatory chronic liver disease with persistent and recurrent immune-mediated liver injury. The exact cause of AIH is still not fully understood, but it is believed to be primarily due to an abnormal activation of the immune system, leading to autoimmune injury caused by the breakdown of autoimmune tolerance. Although the pathogenesis of AIH remains unclear, recent studies have shown that abnormalities in amino acid metabolism play significant roles in its development. These abnormalities in amino acid metabolism can lead to remodeling of metabolic processes, activation of signaling pathways, and immune responses, which may present new opportunities for clinical intervention in AIH. In this paper, we first briefly outline the recent progress of clinically relevant research on AIH, focusing on the role of specific amino acid metabolism (including glutamine, cysteine, tryptophan, branched-chain amino acids, etc.) and their associated metabolites, as well as related pathways, in the development of AIH. Furthermore, we discuss the scientific issues that remain to be resolved regarding amino acid metabolism, AIH development and related clinical interventions, with the aim of contributing to the future development of amino acid metabolism-based as a new target for the clinical diagnosis and treatment of AIH.

Identification of tumor-suppressive miRNAs that target amino acid transporter LAT1 and exhibit anti-proliferative effects on cholangiocarcinoma cells

Amino acid transporter LAT1 is highly upregulated in various cancer types, including cholangiocarcinoma (CHOL), and contributes to the rapid proliferation of cancer cells and disease progression. However, the molecular mechanisms underlying the pathological upregulation of LAT1 remain largely unknown. This study pursued the possibility of miRNA-mediated regulation of the LAT1 expression in CHOL cells. Using online target prediction methods, we extracted five candidate miRNAs commonly predicted to regulate the LAT1 expression. Three of them, miR-194-5p, miR-122-5p, and miR-126-3p, were significantly downregulated in CHOL cancer compared to normal tissues. Correlation analysis revealed weak-to-moderate negative correlations between the expression of these miRNAs and LAT1 mRNA in CHOL cancer tissues. We selected miR-194-5p and miR-122-5p for further analyses and found that both miRNAs functionally target 3'UTR of LAT1 mRNA by a luciferase-based reporter assay. Transfection of the miRNA mimics significantly suppressed the LAT1 expression at mRNA and protein levels and inhibited the proliferation of CHOL cells, with a trend of affecting intracellular amino acids and amino acid-related signaling pathways. This study indicates that the decreased expression of these LAT1-targeting tumor-suppressive miRNAs contributes to the upregulation of LAT1 and the proliferation of CHOL cells, highlighting their potential for developing novel cancer therapeutics and diagnostics.

ALYREF-JunD-SLC7A5 axis promotes pancreatic ductal adenocarcinoma progression through epitranscriptome-metabolism reprogramming and immune evasion

Pancreatic ductal adenocarcinoma (PDAC) is a kind of tumor lacking nutrients due to its poor vascularity and desmoplasia. Recent studies have shown that cancer cells might achieve growth advantage through epitranscriptome reprogramming. However, the role of m5C in PDAC was not fully understood. We found that Aly/REF export factor (ALYREF), a reader of m5C modification, was overexpressed in PDAC, and associated with bad prognosis. In addition, the ALYREF expression was negatively related to CD8+ T cells infiltration in clinical samples. ALYREF knockdown decreased tumor growth in vivo partly dependent of immunity. ALYREF silencing decreased SLC7A5 expression and subsequently inactivated mTORC1 pathway, resulting in decreased tumor proliferation. Mechanically, ALYREF specifically recognized m5C sites in JunD mRNA, maintained the stabilization of JunD mRNA and subsequently upregulated transcription of SLC7A5. Since SLC7A5 was a key transporter of large neutral amino acids (LNAAs), overexpression of SLC7A5 on tumor cells depleted amino acid in microenvironment and restricted CD8+ T cells function. Moreover, ALYREF-JunD-SLC7A5 axis was overexpressed and negatively related with survival through TMA assays. In conclusion, this research revealed the relationship between m5C modification, amino acid transportation and immune microenvironment. ALYREF might be a novel target for PDAC metabolic vulnerability and immune surveillance.

Metabolic Adaptation and Cellular Stress Response As Targets for Cancer Therapy

Cancer cells, which divide indefinitely and without control, are frequently exposed to various stress factors but manage to adapt and survive. The mechanisms by which cancer cells maintain cellular homeostasis and exploit stress conditions are not yet clear. Here, we elucidate the roles of diverse cellular metabolism and its regulatory mechanisms, highlighting the essential role of metabolism in cellular composition and signal transduction. Cells respond to various stresses, including DNA damage, energy stress, and oxidative stress, thereby causing metabolic alteration. We provide profound insight into the adaptive mechanisms employed by cancer cells to ensure their survival among internal and external stressors through a comprehensive analysis of the correlation between metabolic alterations and cellular stress. Furthermore, this research establishes a robust framework for the development of innovative therapeutic strategies that specifically target the cellular adaptations of cancer cells.

Cell polarity changes in cancer initiation and progression

Cell polarity, which consists of the morphological, structural, and functional organization of cells along a defined axis, is a feature of healthy cells and tissues. In contrast, abnormal polarity is a hallmark of cancer cells. At the molecular level, key evolutionarily conserved proteins that control polarity establishment and maintenance in various contexts are frequently altered in cancer, but the relevance of these molecular alterations in the oncogenic processes is not always clear. Here, we summarize the recent findings, shedding new light on the involvement of polarity players in cancer development, and discuss the possibility of harnessing cell polarity changes to better predict, diagnose, and cure cancers.

LLGL2 Inhibits Ovarian Cancer Metastasis by Regulating Cytoskeleton Remodeling via ACTN1

Epithelial ovarian cancer is the most lethal gynecological malignant tumor. Although debulking surgery, chemotherapy, and PARP inhibitors have greatly improved survival, the prognosis for patients with advanced EOC without HRD is still poor. LLGL2, as a cell polarity factor, is involved in maintaining cell polarity and asymmetric cell division. In the study of zebrafish development, LLGL2 regulated the proliferation and migration of epidermal cells and the formation of cortical F-actin. However, the role of LLGL2 in ovarian cancer has not been described. Our study found, through bioinformatics analysis, that low expression of LLGL2 was significantly associated with a more advanced stage and a higher grade of EOC and a poorer survival of patients. Functional experiments that involved LLGL2 overexpression and knockdown showed that LLGL2 inhibited the migration and invasion abilities of ovarian cancer cells in vitro, without affecting their proliferation. LLGL2-overexpressing mice had fewer metastatic implant foci than the controls in vivo. Mechanistically, immunoprecipitation combined with mass spectrometry analysis suggested that LLGL2 regulated cytoskeletal remodeling by interacting with ACTN1. LLGL2 altered the intracellular localization and function of ACTN1 without changing its protein and mRNA levels. Collectively, we uncovered that LLGL2 impaired actin filament aggregation into bundles by interacting with ACTN1, which led to cytoskeleton remodeling and inhibition of the invasion and metastasis of ovarian cancer cells.

Hypoxia-mimetic by CoCl2 increases SLC7A5 expression in breast cancer cells in vitro

OBJECTIVE

Increased expression of the amino acid transporter solute Carrier Family 7 Member 5 (SLC7A5) has been observed in neoplastic cells during hypoxic conditions in vitro, indicating an adaptation for cell survival. To further explore this, we evaluated hypoxia-mimetic by CoCl2 as a model for hypoxia in breast cancer cell lines and the effect on SLC257A5 expression. Four different breast cancer cell lines (MCF7, T-47D, BT-474 and ZR-75-1) were exposed to 100 µM CoCl2 for 48 h. Subsequently, cell viability, gene- and protein expression analyses were performed.

RESULTS

The gene expression of VEGF, a marker of hypoxia, was significantly elevated in all four cell lines compared to the control (p < 0.0001), indicating that CoCl2 exposure generates a hypoxic response. Moreover, CoCl2 exposure significantly upregulated SLC7A5 gene expression in T-47D (p < 0.001), BT-474 (p < 0.0001) and ZR-75-1 (p < 0.0001) cells, as compared to vehicle control. Immunofluorescence staining showed increased SLC7A5 protein expression in MCF7, T-47D and BT-474 cells compared to vehicle control. This report suggests that hypoxia-mimetic by CoCl2 can be used as a simple model for inducing hypoxia in breast cancer cell lines and in fact influence SLC7A5 gene and protein expression in vitro.

Attention-based GCN integrates multi-omics data for breast cancer subtype classification and patient-specific gene marker identification

Breast cancer is a heterogeneous disease and can be divided into several subtypes with unique prognostic and molecular characteristics. The classification of breast cancer subtypes plays an important role in the precision treatment and prognosis of breast cancer. Benefitting from the relation-aware ability of a graph convolution network (GCN), we present a multi-omics integrative method, the attention-based GCN (AGCN), for breast cancer molecular subtype classification using messenger RNA expression, copy number variation and deoxyribonucleic acid methylation multi-omics data. In the extensive comparative studies, our AGCN models outperform state-of-the-art methods under different experimental conditions and both attention mechanisms and the graph convolution subnetwork play an important role in accurate cancer subtype classification. The layer-wise relevance propagation (LRP) algorithm is used for the interpretation of model decision, which can identify patient-specific important biomarkers that are reported to be related to the occurrence and development of breast cancer. Our results highlighted the effectiveness of the GCN and attention mechanisms in multi-omics integrative analysis and the implement of the LRP algorithm can provide biologically reasonable insights into model decision.

Serum branched amino acids and the risk of all-cause mortality: a meta-analysis and systematic review

Recently, the serum levels of branched-chain amino acids (BCAAs) have been considered as an indicator to evaluate health status and predict chronic diseases risk. This systematic review and meta-analysis aimed to assess the relationship between Serum BCAAs and the risk of all-cause mortality. We carried out a comprehensive and systematic search in various important databases, including PubMed, Scopus, and Web of Science databases to find the relevant studies published up to October 2022 with no language, design, or time limitation. We extracted the reported hazard ratio (HR) with 95% confidence interval (CI) and odds ratio (OR) with 95%CI in cohorts and case-control studies, respectively, and computed the log HR or OR and its standard error. Then, we used the random-effects model with inverse variance weighting method for the present meta-analysis, to calculate the pooled effect size. Ten observational studies, including nine cohort studies and one case-control study, were included in the present meta-analysis. The number of participants ranges from 53 to 26,711, with an age range of 18-99 years. During 6 months to 24 years of follow-up, 3599 deaths were ascertained. The pooled results indicated that there was no significant association between serum BCAAs (RR: 1.17; 95% CI 0.85-1.60), isoleucine (RR: 1.41; 95%CI 0.92-2.17), leucine (RR: 1.13; 95% CI 0.94-1.36), and valine (RR: 1.02; 95%CI 0.86-1.22) and all-cause mortality. Also, there was significant heterogeneity between studies for serum BCAAs (I2 = 74.1% and P-heterogeneity = 0.021), isoleucine (I2 = 89.4% and P-heterogeneity < 0.001), leucine (I2 = 87.8% and P-heterogeneity < 0.001), and valine (I2 = 86.6% and P-heterogeneity < 0.001). Our results suggested that the serum BCAAs and its components, including isoleucine, leucine, and valine, were not associated with the risk of all-cause mortality.

The effects of environmental aryl hydrocarbon receptor ligands on signaling and cell metabolism in cancer

Dioxin and dioxin-like compounds are chlorinated organic pollutants formed during the manufacturing of other chemicals. Dioxins are ligands of the aryl hydrocarbon receptor (AHR), that induce AHR-mediated biochemical and toxic responses and are persistent in the environment. 2,3,7,8- tetrachlorodibenzo para dioxin (TCDD) is the prototypical AHR ligand and its effects represent dioxins. TCDD induces toxicity, immunosuppression and is a suspected tumor promoter. The role of TCDD in cancer however is debated and context-dependent. Environmental particulate matter, polycyclic aromatic hydrocarbons, perfluorooctane sulfonamide, endogenous AHR ligands, and cAMP signaling activate AHR through TCDD-independent pathways. The effect of activated AHR in cancer is context-dependent. The ability of FDA-approved drugs to modulate AHR activity has sparked interest in their repurposing for cancer therapy. TCDD by interfering with endogenous pathways, and overstimulating other endogenous pathways influences all stages of cancer. Herein we review signaling mechanisms that activate AHR and mechanisms by which activated AHR modulates signaling in cancer including affected metabolic pathways.

RNA binding motif protein 45-mediated phosphorylation enhances protein stability of ASCT2 to promote hepatocellular carcinoma progression

Targeting metabolic remodeling represents a potentially promising strategy for hepatocellular carcinoma (HCC) therapy. In-depth understanding on the regulation of the glutamine transporter alanine-serine-cysteine transporter 2 (ASCT2) contributes to the development of novel promising therapeutics. As a developmentally regulated RNA binding protein, RBM45 is capable to shuttle between nucleus and cytoplasm, and directly interacts with proteins. By bioinformatics analysis, we screened out that RBM45 was elevated in the HCC patient specimens and positively correlated with poor prognosis. RBM45 promoted cell proliferation, boosted xenograft tumorigenicity and accelerated HCC progression. Using untargeted metabolomics, it was found that RBM45 interfered with glutamine metabolism. Further results demonstrated that RBM45 positively associated with ASCT2 in human and mouse specimens. Moreover, RBM45 enhanced ASCT2 protein stability by counteracting autophagy-independent lysosomal degradation. Significantly, wild-type ASCT2, instead of phospho-defective mutants, rescued siRBM45-suppressed HCC cell proliferation. Using molecular docking approaches, we found AG-221, a mutant isocitrate dehydrogenase 2 (mIDH2) inhibitor for acute myeloid leukemia therapy, pharmacologically perturbed RBM45-ASCT2 interaction, decreased ASCT2 stability and suppressed HCC progression. These findings provide evidence that RBM45 plays a crucial role in HCC progression via interacting with and counteracting the degradation of ASCT2. Our findings suggest a novel alternative structural sites for the design of ASCT2 inhibitors and the agents interfering with RBM45-ASCT2 interaction may be a potential direction for HCC drug development.

Molecular classification of hormone receptor-positive HER2-negative breast cancer

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most prevalent type of breast cancer, in which endocrine therapy resistance and distant relapse remain unmet challenges. Accurate molecular classification is urgently required for guiding precision treatment. We established a large-scale multi-omics cohort of 579 patients with HR+/HER2- breast cancer and identified the following four molecular subtypes: canonical luminal, immunogenic, proliferative and receptor tyrosine kinase (RTK)-driven. Tumors of these four subtypes showed distinct biological and clinical features, suggesting subtype-specific therapeutic strategies. The RTK-driven subtype was characterized by the activation of the RTK pathways and associated with poor outcomes. The immunogenic subtype had enriched immune cells and could benefit from immune checkpoint therapy. In addition, we developed convolutional neural network models to discriminate these subtypes based on digital pathology for potential clinical translation. The molecular classification provides insights into molecular heterogeneity and highlights the potential for precision treatment of HR+/HER2- breast cancer.

The Role of Amino Acids in the Diagnosis, Risk Assessment, and Treatment of Breast Cancer: A Review

This review summarizes the role of amino acids in the diagnosis, risk assessment, imaging, and treatment of breast cancer. It was shown that the content of individual amino acids changes in breast cancer by an average of 10-15% compared with healthy controls. For some amino acids (Thr, Arg, Met, and Ser), an increase in concentration is more often observed in breast cancer, and for others, a decrease is observed (Asp, Pro, Trp, and His). The accuracy of diagnostics using individual amino acids is low and increases when a number of amino acids are combined with each other or with other metabolites. Gln/Glu, Asp, Arg, Leu/Ile, Lys, and Orn have the greatest significance in assessing the risk of breast cancer. The variability in the amino acid composition of biological fluids was shown to depend on the breast cancer phenotype, as well as the age, race, and menopausal status of patients. In general, the analysis of changes in the amino acid metabolism in breast cancer is a promising strategy not only for diagnosis, but also for developing new therapeutic agents, monitoring the treatment process, correcting complications after treatment, and evaluating survival rates.

Targeting glutamine metabolic reprogramming of SLC7A5 enhances the efficacy of anti-PD-1 in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a heterogeneous disease that is characterized by metabolic disruption. Metabolic reprogramming and tumor cell immune escape play indispensable roles in the tumorigenesis that leads to TNBC.

Methods

In this study, we constructed and validated two prognostic glutamine metabolic gene models, Clusters A and B, to better discriminate between groups of TNBC patients based on risk. Compared with the risk Cluster A patients, the Cluster B patients tended to exhibit better survival outcomes and higher immune cell infiltration. In addition, we established a scoring system, the glutamine metabolism score (GMS), to assess the pattern of glutamine metabolic modification.

Results

We found that solute carrier family 7 member 5 (SLC7A5), an amino acid transporter, was the most important gene and plays a vital role in glutamine metabolism reprogramming in TNBC cells. Knocking down SLC7A5 significantly inhibited human and mouse TNBC cell proliferation, migration, and invasion. In addition, downregulation of SLC7A5 increased CD8+ T-cell infiltration. The combination of a SLC7A5 blockade mediated via JPH203 treatment and an anti-programmed cell death 1 (PD-1) antibody synergistically increased the immune cell infiltration rate and inhibited tumor progression.

Conclusions

Hence, our results highlight the molecular mechanisms underlying SLC7A5 effects and lead to a better understanding of the potential benefit of targeting glutamine metabolism in combination with immunotherapy as a new therapy for TNBC.

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.

The Interplay between Microbiota and Chemotherapy-Derived Metabolites in Breast Cancer

The most common cancer in women is breast cancer, which is also the second leading cause of death in this group. It is, however, important to note that some women will develop or will not develop breast cancer regardless of whether certain known risk factors are present. On the other hand, certain compounds are produced by bacteria in the gut, such as short-chain fatty acids, secondary bile acids, and other metabolites that may be linked to breast cancer development and mediate the chemotherapy response. Modeling the microbiota through dietary intervention and identifying metabolites directly associated with breast cancer and its complications may be useful to identify actionable targets and improve the effect of antiangiogenic therapies. Metabolomics is therefore a complementary approach to metagenomics for this purpose. As a result of the combination of both techniques, a better understanding of molecular biology and oncogenesis can be obtained. This article reviews recent literature about the influence of bacterial metabolites and chemotherapy metabolites in breast cancer patients, as well as the influence of diet.

Comparative genomics analyses reveal sequence determinants underlying interspecies variations in injury-responsive enhancers

BACKGROUND

Injury induces profound transcriptional remodeling events, which could lead to only wound healing, partial tissue repair, or perfect regeneration in different species. Injury-responsive enhancers (IREs) are cis-regulatory elements activated in response to injury signals, and have been demonstrated to promote tissue regeneration in some organisms such as zebrafish and flies. However, the functional significances of IREs in mammals remain elusive. Moreover, whether the transcriptional responses elicited by IREs upon injury are conserved or specialized in different species, and what sequence features may underlie the functional variations of IREs have not been elucidated.

RESULTS

We identified a set of IREs that are activated in both regenerative and non-regenerative neonatal mouse hearts upon myocardial ischemia-induced damage by integrative epigenomic and transcriptomic analyses. Motif enrichment analysis showed that AP-1 and ETS transcription factor binding motifs are significantly enriched in both zebrafish and mouse IREs. However, the IRE-associated genes vary considerably between the two species. We further found that the IRE-related sequences in zebrafish and mice diverge greatly, with the loss of IRE inducibility accompanied by a reduction in AP-1 and ETS motif frequencies. The functional turnover of IREs between zebrafish and mice is correlated with changes in transcriptional responses of the IRE-associated genes upon injury. Using mouse cardiomyocytes as a model, we demonstrated that the reduction in AP-1 or ETS motif frequency attenuates the activation of IREs in response to hypoxia-induced damage.

CONCLUSIONS

By performing comparative genomics analyses on IREs, we demonstrated that inter-species variations in AP-1 and ETS motifs may play an important role in defining the functions of enhancers during injury response. Our findings provide important insights for understanding the molecular mechanisms of transcriptional remodeling in response to injury across species.

Glutamine metabolism in breast cancer and possible therapeutic targets

Cancer is characterized by metabolic reprogramming, which is a hot topic in tumor treatment research. Cancer cells alter metabolic pathways to promote their growth, and the common purpose of these altered metabolic pathways is to adapt the metabolic state to the uncontrolled proliferation of cancer cells. Most cancer cells in a state of nonhypoxia will increase the uptake of glucose and produce lactate, called the Warburg effect. Increased glucose consumption is used as a carbon source to support cell proliferation, including nucleotide, lipid and protein synthesis. In the Warburg effect, pyruvate dehydrogenase activity decreases, thereby disrupting the TCA cycle. In addition to glucose, glutamine is also an important nutrient for the growth and proliferation of cancer cells, an important carbon bank and nitrogen bank for the growth and proliferation of cancer cells, providing ribose, nonessential amino acids, citrate, and glycerin necessary for cancer cell growth and proliferation and compensating for the reduction in oxidative phosphorylation pathways in cancer cells caused by the Warburg effect. In human plasma, glutamine is the most abundant amino acid. Normal cells produce glutamine via glutamine synthase (GLS), but the glutamine synthesized by tumor cells is insufficient to meet their high growth needs, resulting in a "glutamine-dependent phenomenon." Most cancers have an increased glutamine demand, including breast cancer. Metabolic reprogramming not only enables tumor cells to maintain the reduction-oxidation (redox) balance and commit resources to biosynthesis but also establishes heterogeneous metabolic phenotypes of tumor cells that are distinct from those of nontumor cells. Thus, targeting the metabolic differences between tumor and nontumor cells may be a promising and novel anticancer strategy. Glutamine metabolic compartments have emerged as promising candidates, especially in TNBC and drug-resistant breast cancer. In this review, the latest discoveries of breast cancer and glutamine metabolism are discussed, novel treatment methods based on amino acid transporters and glutaminase are discussed, and the relationship between glutamine metabolism and breast cancer metastasis, drug resistance, tumor immunity and ferroptosis are explained, which provides new ideas for the clinical treatment of breast cancer.

Mechanisms of drug resistance in breast cancer liver metastases: Dilemmas and opportunities

Breast cancer is the leading cause of cancer-related deaths in females worldwide, and the liver is one of the most common sites of distant metastases in breast cancer patients. Patients with breast cancer liver metastases face limited treatment options, and drug resistance is highly prevalent, leading to a poor prognosis and a short survival. Liver metastases respond extremely poorly to immunotherapy and have shown resistance to treatments such as chemotherapy and targeted therapies. Therefore, to develop and to optimize treatment strategies as well as to explore potential therapeutic approaches, it is crucial to understand the mechanisms of drug resistance in breast cancer liver metastases patients. In this review, we summarize recent advances in the research of drug resistance mechanisms in breast cancer liver metastases and discuss their therapeutic potential for improving patient prognoses and outcomes.

Lethal giant larvae gene family ( Llgl1 and Llgl2 ) functions as a tumor suppressor in mouse skin epidermis

Loss of cell polarity and tissue disorganization occurs in majority of epithelial cancers. Studies in simple model organisms identified molecular mechanisms responsible for the establishment and maintenance of cellular polarity, which play a pivotal role in establishing proper tissue architecture. The exact role of these cell polarity pathways in mammalian cancer is not completely understood. Here we analyzed the mammalian orthologs of drosophila apical-basal polarity gene lethal giant larvae ( lgl ), which regulates asymmetric stem cell division and functions as a tumor suppressor in flies. There are two mammalian orthologs of lgl ( Llgl1 and Llgl2 ). To determine the role of the entire lgl signaling pathway in mammals we generated mice with ablation of both Llgl1 and Llgl2 in skin epidermis using K14-Cre ( Llgl1/2 ^-/- cKO mice). Surprisingly, we found that ablation of Llgl1/2 genes does not impact epidermal polarity in adult mice. However, old Llgl1/2 cKO mice present with focal skin lesions which are missing epidermal layer and ripe with inflammation. To determine the role of lgl signaling pathway in cancer we generated Trp53 ^-/- /Llgl1/2 ^-/- cKO and Trp53 ^-/+ /Llgl1/2 ^-/- cKO mice. Loss of Llgl1/2 promoted squamous cell carcinoma (SCC) development in Trp53 ^-/- cKO and caused SCC in Trp53 ^-/+ cKO mice, while no cancer was observed in Trp53 ^-/+ cKO controls. Mechanistically, we show that ablation of Llgl1/2 causes activation of aPKC and upregulation of NF-kB signaling pathway, which may be necessary for SCC in Trp53 ^-/+ /Llgl1/2 ^-/- cKO mice. We conclude that Lgl signaling pathway functions as a tumor suppressor in mammalian skin epidermis.

Nutrient transporters: connecting cancer metabolism to therapeutic opportunities

Cancer cells rely on certain extracellular nutrients to sustain their metabolism and growth. Solute carrier (SLC) transporters enable cells to acquire extracellular nutrients or shuttle intracellular nutrients across organelles. However, the function of many SLC transporters in cancer is unknown. Determining the key SLC transporters promoting cancer growth could reveal important therapeutic opportunities. Here we summarize recent findings and knowledge gaps on SLC transporters in cancer. We highlight existing inhibitors for studying these transporters, clinical trials on treating cancer by blocking transporters, and compensatory transporters used by cancer cells to evade treatment. We propose targeting transporters simultaneously or in combination with targeted therapy or immunotherapy as alternative strategies for effective cancer therapy.

High dose isoleucine stabilizes nuclear PTEN to suppress the proliferation of lung cancer

PURPOSE

Cancer cells require a supply of amino acids, particularly essential amino acids such as branched-chain amino acids (BCAAs, i.e., valine, leucine, and isoleucine), to meet the increased nutrient demands of malignant tumors. The cell-autonomous and non-autonomous roles of altered BCAA supply have been implicated in cancer progression. The critical proteins involved in BCAA uptake, transport, metabolism, etc. serve as potential therapeutic biomarkers in human cancers. Here, we summarize the potential anti-tumor mechanism of BCAA by exploring the chain reaction triggered by increased BCAA supply in the tumor.

METHOD

A system-wide strategy was employed to provide a generic solution to establish the links between BCAA and cancer based on comprehensive omics, molecular experimentation, and data analysis.

RESULTS

BCAA over-supplementation (900 mg/kg) significantly inhibited tumor growth and reduced tumor burden, with isoleucine having the most pronounced effect. Surprisingly, isoleucine inhibited tumor growth independently of mTORC1 activation, a classical amino acid sensor. Exploratory transcriptome analysis revealed that Phosphatase and tensin homolog (PTEN) is the critical factor in the anti-tumor effect of isoleucine. By inhibiting PTEN ubiquitination, isoleucine can promote PTEN nuclear import and maintain PTEN nuclear stability. Interestingly, this process was regulated by isoleucine-tRNA ligase, cytoplasmic (IARS), a direct target of isoleucine. We demonstrated the enhanced interaction between IARS and PTEN in the presence of excess isoleucine. At the same time, IARS knockout leads to loss of isoleucine tumor suppressor ability.

CONCLUSION

Overall, our results provide insights into the regulation of the IARS-PTEN anti-tumor axis by isoleucine and reveal a unique therapeutic approach based on enhancing cellular isoleucine supply.

Protamine 1 as a secreted colorectal cancer-specific antigen facilitating G1/S phase transition under nutrient stress conditions

PURPOSE

Cancer testis antigens (CTAs) are optimal tumor diagnostic markers and involved in carcinogenesis. However, colorectal cancer (CRC) related CTAs are less reported with impressive diagnostic capability or relevance with tumor metabolism rewiring. Herein, we demonstrated CRC-related CTA, Protamine 1 (PRM1), as a promising diagnostic marker and involved in regulation of cellular growth under nutrient deficiency.

METHODS

Transcriptomics of five paired CRC tissues was used to screen CRC-related CTAs. Capability of PRM1 to distinguish CRC was studied by detection of clinical samples through enzyme linked immunosorbent assay (ELISA). Cellular functions were investigated in CRC cell lines through in vivo and in vitro assays.

RESULTS

By RNA-seq and detection in 824 clinical samples from two centers, PRM1 expression were upregulated in CRC tissues and patients` serum. Serum PRM1 showed impressive accuracy to diagnose CRC from healthy controls and benign gastrointestinal disease patients, particularly more sensitive for early-staged CRC. Furthermore, we reported that when cells were cultured in serum-reduced medium, PRM1 secretion was upregulated, and secreted PRM1 promoted CRC growth in culture and in mice. Additionally, G1/S phase transition of CRC cells was facilitated by PRM1 protein supplementation and overexpression via activation of PI3K/AKT/mTOR pathway in serum deficient medium.

CONCLUSIONS

In general, our research presented PRM1 as a specific CRC antigen and illustrated the importance of PRM1 in CRC metabolism rewiring. The new vulnerability of CRC cells was also provided with the potential to be targeted in future. Diagnostic value and grow factor-like biofunction of PRM1 A represents the secretion process of PRM1 regulated by nutrient deficiency. B represents activation of PI3K/AKT/mTOR pathway of secreted PRM1.

Polarity in breast development and cancer

Mammary gland development and breast cancer progression are associated with extensive remodeling of epithelial tissue architecture. Apical-basal polarity is a key feature of epithelial cells that coordinates key elements of epithelial morphogenesis including cell organization, proliferation, survival, and migration. In this review we discuss advances in our understanding of how apical-basal polarity programs are used in breast development and cancer. We describe cell lines, organoids, and in vivo models commonly used for studying apical-basal polarity in breast development and disease and discuss advantages and limitations of each. We also provide examples of how core polarity proteins regulate branching morphogenesis and lactation during development. We describe alterations to core polarity genes in breast cancer and their associations with patient outcomes. The impact of up- or down-regulation of key polarity proteins in breast cancer initiation, growth, invasion, metastasis, and therapeutic resistance are discussed. We also introduce studies demonstrating that polarity programs are involved in regulating the stroma, either through epithelial-stroma crosstalk, or through signaling of polarity proteins in non-epithelial cell types. Overall, a key concept is that the function of individual polarity proteins is highly contextual, depending on developmental or cancer stage and cancer subtype.

SOX2 inhibits LLGL2 polarity protein in esophageal squamous cell carcinoma via miRNA-142-3p

ABBREVIATIONS

CCK-8, Cell Counting Kit 8; Chip, Chromatin Immunoprecipitation; EC, Esophageal cancer; EMT, epithelial-to-mesenchymal transition; ESCC, Esophageal squamous cell carcinomas; LLGL2, lethal (2) giant larvae protein homolog 2; LLGL2ov, LLGL2 overexpression; MET, mesenchymal-epithelial transition; miRNAs, MicroRNAs; PRM-MS, Parallel reaction monitoring-Mass spectrometry; SD, Standard deviation; SOX, sex determining region Y (SRY)-like box; SOX2-Kd, SOX2-knockdwon; TUNEL, TdT-mediated dUTP Nick-End Labeling.

NUPR1 imparts oncogenic potential in bladder cancer

BACKGROUND

NUPR1, or p8, is a small chromatin protein that plays a central role in the resistance to treatment and progression of cancer. Nevertheless, the molecular mechanism of NUPR1 in bladder cancer (BLCA) remains unclear.

METHODS

We used online databases and immunohistochemistry (IHC) to explore the expression of NUPR1 in BLCA tissues and controls. Lentivirus-mediated small interfering ribonucleic acid (siRNA) was used to knockdown the expression of NUPR1 in two human BLCA cell lines. We used an in vivo experiment to investigate the effect of NUPR1 knockdown on the growth of BLCA. Moreover, an in silico analysis was conducted to assess the differential expression profile after NUPR1 interference. The CIBERSORT algorithm was utilized to evaluate the effects of tumor-infiltrating immune cells among BLCA patients.

RESULTS

The expression of NUPR1 in BLCA tissues was significantly higher than in the control. NUPR1 expression was also positively correlated with the stage of BLCA. After lentivirus-mediated interference, the expression of NUPR1 was significantly down-regulated in BLCA cell lines. The cell cycle was blocked in G1 phase and the cell proportion of S phase was decreased in both two cell lines. Moreover, in vivo experiment revealed that the tumor growth of BLCA can be delayed by inhibiting the expression of NUPR1. Both in silico analysis and functional experiments revealed that NUPR1 was correlated with epithelial-mesenchymal transition (EMT). We also revealed that macrophages were the most related immune cells associated with the expression of NUPR1 in BLCA.

CONCLUSIONS

This study suggests that NUPR1 plays a carcinogenic role in BLCA. NUPR1 lentivirus-mediated interference could interfere with cycle progression of the BLCA cell, resulting in cell cycle arrest in the G1-phase. The carcinogenic effect of NUPR1 in BLCA is likely achieved through EMT. NUPR1 is correlated with the M0-type macrophage markers CD68 and CD11b-integrin.

Metabolomics by NMR Combined with Machine Learning to Predict Neoadjuvant Chemotherapy Response for Breast Cancer

Simple Summary

Neoadjuvant chemotherapy (NACT) is offered to breast cancer (BC) patients to downstage the disease. However, some patients may not respond to NACT, being resistant. We used the serum metabolic profile by Nuclear Magnetic Resonance (NMR) combined with disease characteristics to differentiate between sensitive and resistant BC patients. We obtained accuracy above 80% for the response prediction and showcased how NMR can substantially enhance the prediction of response to NACT.

Abstract

Neoadjuvant chemotherapy (NACT) is offered to patients with operable or inoperable breast cancer (BC) to downstage the disease. Clinical responses to NACT may vary depending on a few known clinical and biological features, but the diversity of responses to NACT is not fully understood. In this study, 80 women had their metabolite profiles of pre-treatment sera analyzed for potential NACT response biomarker candidates in combination with immunohistochemical parameters using Nuclear Magnetic Resonance (NMR). Sixty-four percent of the patients were resistant to chemotherapy. NMR, hormonal receptors (HR), human epidermal growth factor receptor 2 (HER2), and the nuclear protein Ki67 were combined through machine learning (ML) to predict the response to NACT. Metabolites such as leucine, formate, valine, and proline, along with hormone receptor status, were discriminants of response to NACT. The glyoxylate and dicarboxylate metabolism was found to be involved in the resistance to NACT. We obtained an accuracy in excess of 80% for the prediction of response to NACT combining metabolomic and tumor profile data. Our results suggest that NMR data can substantially enhance the prediction of response to NACT when used in combination with already known response prediction factors.

Bioinformatics Identification of Ferroptosis-Associated Biomarkers and Therapeutic Compounds in Psoriasis

Purpose. Psoriasis is closely linked to ferroptosis. This study aimed to identify potential ferroptosis-associated genes in psoriasis using bioinformatics. Methods. Data from the GSE30999 dataset was downloaded from the Gene Expression Omnibus (GEO), and the ferroptosis-associated genes were retrieved from FerrDb. The differentially expressed ferroptosis-associated genes were identified using Venn diagrams. Subsequently, a network of protein-protein interactions (PPIs) between psoriasis targets and ferroptosis-associated genes was constructed based on the STRING database and analyzed by Cytoscape software. The Metascape portal conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Moreover, the expression of ferroptosis-related genes was verified in the GSE13355 dataset. Finally, the verified genes were used to predict the therapeutic drugs for psoriasis using the DGIdb/CMap database. SwissDock was used to examine ligand docking, and UCSF Chimera displayed the results visually. Results. Among 85 pairs of psoriasis lesion (LS) and no-lesion (NL) samples from patients, 19 ferroptosis-associated genes were found to be differentially expressed (3 upregulated genes and 16 downregulated genes). Based on the PPI results, these ferroptosis-associated genes interact with each other. The GO and KEGG enrichment analysis of differentially expressed ferroptosis-related genes indicated several enriched terms related to the oxidative stress response. The GSE13355 dataset verified the results of the bioinformatics analysis obtained from the GSE30999 dataset regarding SLC7A5, SLC7A11, and CHAC1. Psoriasis-related compounds corresponding to SLC7A5 and SLC7A11 were also identified, including Melphalan, Quisqualate, Riluzole, and Sulfasalazine. Conclusion. We identified 3 differentially expressed ferroptosis-related genes through bioinformatics analysis. SLC7A5, SLC7A11, and CHAC1 may affect the development of psoriasis by regulating ferroptosis. These results open new avenues in understanding the treatment of psoriasis.

Co-expression effect of LLGL2 and SLC7A5 to predict prognosis in ERα-positive breast cancer

Lethal giant larvae homolog 2 (LLGL2) and solute carrier family 7 member 5 (SLC7A5) have been reported to be involved in resistance to endocrine therapy. This study aimed to assess the effects of LLGL2/SLC7A5 co-expression in predicting prognosis and response to tamoxifen therapy in ERα-positive breast cancer patients according to LLGL2/SLC7A5 mRNA and protein expression in long-term follow-up invasive breast cancer tissues. We identified that low LLGL2/SLC7A5 mRNA co-expression (LLGL2^low/SLC7A5^low) was associated with disease-free survival (DFS) compared with other combination groups in all breast cancer patients. In ERα-positive breast cancer patients, LLGL2^low/SLC7A5^low showed longer DFS and overall survival (OS) compared with LLGL2^high/SLC7A5^high and a positive trend of longer survival compared with the other combination groups. We also observed that LLGL2^low/SLC7A5^low showed longer survival compared with LLGL2^high/SLC7A5^high in ERα-positive breast cancer patients receiving adjuvant tamoxifen therapy. Multivariate analysis demonstrated that LLGL2^low/SLC7A5^low was an independent favorable prognostic factor of both DFS and OS, not only in all breast cancer patients, but also in ERα-positive breast cancer patients. High co-expression of LLGL2 and SLC7A5 protein showed a positive trend of shorter survival. Our study showed that co-expression of LLGL2 and SLC7A5 mRNA is a promising candidate biomarker in early breast cancer patients.

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.

Hormone-Glutamine Metabolism: A Critical Regulatory Axis in Endocrine-Related Cancers

The endocrine-related cancers and hormones are undoubtedly highly interconnected. How hormones support or repress tumor induction and progression has been extensively profiled. Furthermore, advances in understanding the role of glutamine metabolism in mediating tumorigenesis and development, coupled with these in-depth studies on hormone (e.g., estrogen, progesterone, androgen, prostaglandin, thyroid hormone, and insulin) regulation of glutamine metabolism, have led us to think about the relationship between these three factors, which remains to be elucidated. Accordingly, in this review, we present an updated overview of glutamine metabolism traits and its influence on endocrine oncology, as well as its upstream hormonal regulation. More importantly, this hormone/glutamine metabolism axis may help in the discovery of novel therapeutic strategies for endocrine-related cancer.

Relationship between metabolic reprogramming and drug resistance in breast cancer

Breast cancer is the leading cause of cancer death in women. At present, chemotherapy is the main method to treat breast cancer in addition to surgery and radiotherapy, but the process of chemotherapy is often accompanied by the development of drug resistance, which leads to a reduction in drug efficacy. Furthermore, mounting evidence indicates that drug resistance is caused by dysregulated cellular metabolism, and metabolic reprogramming, including enhanced glucose metabolism, fatty acid synthesis and glutamine metabolic rates, is one of the hallmarks of cancer. Changes in metabolism have been considered one of the most important causes of resistance to treatment, and knowledge of the mechanisms involved will help in identifying potential treatment deficiencies. To improve women’s survival outcomes, it is vital to elucidate the relationship between metabolic reprogramming and drug resistance in breast cancer. This review analyzes and investigates the reprogramming of metabolism and resistance to breast cancer therapy, and the results offer promise for novel targeted and cell-based therapies.

Silencing of LLGL2 Suppresses the Estradiol-Induced BPH-1 Cell Proliferation through the Regulation of Autophagy

Lethal giant larvae (Lgl) is an apical-basal polarity gene first identified in Drosophila. LLGL2 is one of the mammalian homologs of Lgl. However, little is known about its function in the prostate. In this study, to explore the new role of LLGL2 in the prostate, we examined the proliferative activity of a BPH-1 cell line, a well-established model for the human prostate biology of benign prostatic hyperplasia (BPH). The expression of LLGL2 was dose-dependently increased in BPH-1 cells after treatment with 17β-estradiol (E2). Additionally, E2 treatment increased the proliferation of the BPH-1 cells. However, the knockdown of LLGL2 with siRNA significantly suppressed the proliferation of the E2-treated BPH-1 cells. Moreover, si-llgl2 treatment up-regulated the expression of LC-3B, ATG7, and p-beclin, which are known to play a pivotal role in autophagosome formation in E2-treated BPH-1 cells. Overexpression of LLGL2 was able to further prove these findings by showing the opposite results from the knockdown of LLGL2 in E2-treated BPH-1 cells. Collectively, our results suggest that LLGL2 is closely involved in the proliferation of prostate cells by regulating autophagosome formation. These results provide a better understanding of the mechanism involved in the effect of LLGL2 on prostate cell proliferation. LLGL2 might serve as a potential target in the diagnosis and/or treatment of human BPH.

Blockade of the amino acid transporter SLC6A14 suppresses tumor growth in colorectal Cancer

Background

The amino acid transporter SLC6A14, which transports 18 of the 20 proteinogenic amino acids, is too low to be detected in healthy normal tissues but is significantly increased in some solid cancers. However, little is known about the roles of SLC6A14 in colorectal cancer (CRC).

Methods

The mRNA and protein levels of SLC6A14 were detected using TCGA database, real-time polymerase chain reaction, western blot, and tissue microarrays, respectively. Amino acids concentration was determined by LC-MS/MS. Cell proliferation and apoptosis were determined using MTT assay and flow cytometry. Transwell invasion assay and wound healing assay were employed to analyze cell migration and invasion. The protein levels of Akt-mTOR signaling pathway and MMPs proteins were detected by western blot.

Results

Both of the mRNA and protein levels of SLC6A14 were upregulated in CRC tissues, and the protein levels of SLC6A14 were closely related to the tumor cells differentiation: the higher the expression of SLC6A14 was, the poorer the differentiation of the tumor cells was. Further knockdown SLC6A14 with siRNA or treatment with α-MT in CRC cell lines reduced cell proliferation and migration in vitro and inhibited xenograft tumor growth in vivo. Mechanistically, SLC6A14 was demonstrated to regulate the expression and phosphorylation of Akt-mTOR, which mediates the promoting tumor growth function of SLC6A14. Blockade of SLC6A14 with α-MT inhibited the activation of mTOR signaling.

Conclusion

SLC6A14 was upregulated in CRC and could promote tumor progression by activating the Akt-mTOR signaling pathway, which may serve as an effective molecular target for the treatment of CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09935-0.

Transport of Biologically Active Ultrashort Peptides Using POT and LAT Carriers

Ultrashort peptides (USPs), consisting of 2–7 amino-acid residues, are a group of signaling molecules that regulate gene expression and protein synthesis under normal conditions in various diseases and ageing. USPs serve as a basis for the development of drugs with a targeted mechanism of action. The purpose of this review is to systematize the available data on USP transport involving POT and LAT transporters in various organs and tissues under normal, pathological and ageing conditions. The carriers of the POT family (PEPT1, PEPT2, PHT1, PHT2) transport predominantly di- and tripeptides into the cell. Methods of molecular modeling and physicochemistry have demonstrated the ability of LAT1 to transfer not only amino acids but also some di- and tripeptides into the cell and out of it. LAT1 and 2 are involved in the regulation of the antioxidant, endocrine, immune and nervous systems’ functions. Analysis of the above data allows us to conclude that, depending on their structure, di- and tripeptides can be transported into the cells of various tissues by POT and LAT transporters. This mechanism is likely to underlie the tissue specificity of peptides, their geroprotective action and effectiveness in the case of neuroimmunoendocrine system disorders.

Altered branched-chain α-keto acid metabolism is a feature of NAFLD in individuals with severe obesity

Hepatic de novo lipogenesis is influenced by the branched-chain α-keto acid dehydrogenase (BCKDH) kinase (BCKDK). Here, we aimed to determine whether circulating levels of the immediate substrates of BCKDH, the branched-chain α-keto acids (BCKAs), and hepatic BCKDK expression are associated with the presence and severity of nonalcoholic fatty liver disease (NAFLD). Eighty metabolites (3 BCKAs, 14 amino acids, 43 acylcarnitines, 20 ceramides) were quantified in plasma from 288 patients with bariatric surgery with severe obesity and scored liver biopsy samples. Metabolite principal component analysis factors, BCKAs, branched-chain amino acids (BCAAs), and the BCKA/BCAA ratio were tested for associations with steatosis grade and presence of nonalcoholic steatohepatitis (NASH). Of all analytes tested, only the Val-derived BCKA, α-keto-isovalerate, and the BCKA/BCAA ratio were associated with both steatosis grade and NASH. Gene expression analysis in liver samples from 2 independent bariatric surgery cohorts showed that hepatic BCKDK mRNA expression correlates with steatosis, ballooning, and levels of the lipogenic transcription factor SREBP1. Experiments in AML12 hepatocytes showed that SREBP1 inhibition lowered BCKDK mRNA expression. These findings demonstrate that higher plasma levels of BCKA and hepatic expression of BCKDK are features of human NAFLD/NASH and identify SREBP1 as a transcriptional regulator of BCKDK.

The multi-molecular mechanisms of tumor-targeted drug resistance in precision medicine

Clinically, cancer drug therapy is still dominated by chemotherapy drugs. Although the emergence of targeted drugs has greatly improved the survival rate of patients with advanced cancer, drug resistance has always been a difficult problem in clinical cancer treatment. At the current level of medicine, most drugs cannot escape the fate of drug resistance. With the emergence and development of gene detection, liquid biopsy ctDNA technology, and single-cell sequencing technology, the molecular mechanism of tumor drug resistance has gradually emerged. Drugs can also be updated in response to drug resistance mechanisms and bring higher survival benefits. The use of new drugs often leads to new mechanisms of resistance. In this review, the multi-molecular mechanisms of drug resistance are introduced, and the overcoming of drug resistance is discussed from the perspective of the tumor microenvironment.

Polarity protein SCRIB interacts with SLC3A2 to regulate proliferation and tamoxifen resistance in ER+ breast cancer

Estrogen receptor (ER) positive breast cancer represents 75% of all breast cancers in women. Although patients with ER+ cancers receive endocrine therapies, more than 30% develop resistance and succumb to the disease, highlighting the need to understand endocrine resistance. Here we show an unexpected role for the cell polarity protein SCRIB as a tumor-promoter and a regulator of endocrine resistance in ER-positive breast cancer cells. SCRIB expression is induced by estrogen signaling in a MYC-dependent manner. SCRIB interacts with SLC3A2, a heteromeric component of leucine amino acid transporter SLC7A5. SLC3A2 binds to the N-terminus of SCRIB to facilitate the formation of SCRIB/SLC3A2/LLGL2/SLC7A5 quaternary complex required for membrane localization of the amino acid transporter complex. Both SCRIB and SLC3A2 are required for cell proliferation and tamoxifen resistance in ER+ cells identifying a new role for the SCRIB/SLC3A2 complex in ER+ breast cancer.

Essential amino acids deprivation is a potential strategy for breast cancer treatment

Aims

The study aimed to search novel, simple and practical index reflecting the level of essential amino acids (EAAs) metabolism in breast cancer (BC), as well as to explore the effect of enhanced EAAs metabolism on the prognosis and immune microenvironment of BC, thus providing new evidence for the application of EAAs deprivation in the BC treatment.

Methods

The study includes the analysis of multi-omics and clinical data of 13 BC cell lines and 2898 BC patients in the public database. Further validation was performed using multi-omics and immunohistochemistry data from 83 BC tissue samples collected at our hospital.

Results

According to the multi-omics data, the SLC7A5 to SLC7A8 Ratio (SSR) score was found to be significantly correlated with the EAAs level and EAAs-metabolic activity of BC, suggesting that the SSR score might be used as a biomarker to assess the degree of EAAs metabolism in BC. Besides, BC patients with high EAAs metabolism had shorter overall survival (OS) time, higher PD-L1 expression, and higher T regulatory cells (Tregs) infiltration, indicating that a high EAAs metabolism was related to a poor prognosis and immune suppression in BC. Additionally, MYC amplification is a critical molecular process in the metabolic reprogramming of EAAs in BC.

Conclusion

EAAs may be a possible therapeutic target for BC treatment.

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A novel biomarker to assess the EAAs metabolism in breast cancer.

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High EAAs metabolism is related to a poor prognosis in breast cancer.

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High EAAs metabolism is also related to immune suppression in breast cancer.

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MYC amplification drives the metabolic reprogramming of EAAs in breast cancer.

The novel indomethacin derivative CZ-212-3 exerts antitumor effects on castration-resistant prostate cancer by degrading androgen receptor and its variants

Androgen receptor (AR) serves as a main therapeutic target for prostate cancer (PCa). However, resistance to anti-androgen therapy (SAT) inevitably occurs. Indomethacin is a nonsteroidal anti-inflammatory drug that exhibits activity against prostate cancer. Recently, we designed and synthesized a series of new indomethacin derivatives (CZ compounds) via Pd (II)-catalyzed synthesis of substituted N-benzoylindole. In this study, we evaluated the antitumor effect of these novel indomethacin derivatives in castration-resistant prostate cancer (CRPC). Upon employing CCK-8 cell viability assays and colony formation assays, we found that these derivatives had high efficacy against CRPC tumor growth in vitro. Among these derivatives, CZ-212-3 exhibited the most potent efficacy against CRPC cell survival and on apoptosis induction. Mechanistically, CZ-212-3 significantly suppressed the expression of AR target gene networks by degrading AR and its variants. Consistently, CZ-212-3 significantly inhibited tumor growth in CRPC cell line-based xenograft and PDX models in vivo. Taken together, the data show that the indomethacin derivative CZ-212-3 significantly inhibited CRPC tumor growth by degrading AR and its variants and could be a promising agent for CRPC therapy.

Studying Cell Polarity Dynamics During Cancer Initiation Using Inducible 3D Organotypic Cultures

Epithelial tissues are highly organized structures that are structured at both the cellular and tissue levels. Individual cells are characterized by an apical membrane facing a central lumen, and a basolateral membrane that contacts adjacent cells and the basement membrane. The maintenance of apical-basal polarity is crucial for maintaining epithelial homeostasis and is considered a barrier to carcinogenesis. Apical-basal cell polarity is compromised in many epithelial cancers, such as breast, lung, and prostate, and has been associated with disease progression. Three-dimensional (3D) organotypic cultures recapitulate the 3D tissue architecture and mechanical properties found in vivo. This chapter describes methods to establish 3D organoids from human cell lines or mouse primary cells with inducible oncogene expression in polarized epithelial structures to investigate mechanisms of tumor initiation, luminal filling, and growth. The method is versatile, and simple modifications can be made to study diverse cell/tissue types and oncogenes.

LGL1 binds to Integrin β1 and inhibits downstream signaling to promote epithelial branching in the mammary gland

Branching morphogenesis is a fundamental process by which organs in invertebrates and vertebrates form branches to expand their surface areas. The current dogma holds that directional cell migration determines where a new branch forms and thus patterns branching. Here, we asked whether mouse Lgl1, a homolog of the Drosophila tumor suppressor Lgl, regulates epithelial polarity in the mammary gland. Surprisingly, mammary glands lacking Lgl1 have normal epithelial polarity, but they form fewer branches. Moreover, we find that Lgl1 null epithelium is unable to directionally migrate, suggesting that migration is not essential for mammary epithelial branching as expected. We show that LGL1 binds to Integrin β1 and inhibits its downstream signaling, and Integrin β1 overexpression blocks epithelial migration, thus recapitulating the Lgl1 null phenotype. Altogether, we demonstrate that Lgl1 modulation of Integrin β1 signaling is essential for directional migration and that epithelial branching in invertebrates and the mammary gland is fundamentally distinct.

Ma et al. show that Lgl1 is essential for mammary gland branching morphogenesis but not epithelial polarity. Lgl1 is required for directional migration by regulating Integrin β1 signaling levels and focal adhesion strengths. Finally, branching mechanisms are distinct between mammary gland and Drosophila systems where directional migration is indispensable.

Expression of 3-Methylcrotonyl-CoA Carboxylase in Brain Tumors and Capability to Catabolize Leucine by Human Neural Cancer Cells

Leucine is an essential, ketogenic amino acid with proteinogenic, metabolic, and signaling roles. It is readily imported from the bloodstream into the brain parenchyma. Therefore, it could serve as a putative substrate that is complementing glucose for sustaining the metabolic needs of brain tumor cells. Here, we investigated the ability of cultured human cancer cells to metabolize leucine. Indeed, cancer cells dispose of leucine from their environment and enrich their media with the metabolite 2-oxoisocaproate. The enrichment of the culture media with a high level of leucine stimulated the production of 3-hydroxybutyrate. When ¹³C₆-leucine was offered, it led to an increased appearance of the heavier citrate isotope with a molar mass greater by two units in the culture media. The expression of 3-methylcrotonyl-CoA carboxylase (MCC), an enzyme characteristic for the irreversible part of the leucine catabolic pathway, was detected in cultured cancer cells and human tumor samples by immunoprobing methods. Our results demonstrate that these cancer cells can catabolize leucine and furnish its carbon atoms into the tricarboxylic acid (TCA) cycle. Furthermore, the release of 3-hydroxybutyrate and citrate by cancer cells suggests their capability to exchange these metabolites with their milieu and the capability to participate in their metabolism. This indicates that leucine could be an additional substrate for cancer cell metabolism in the brain parenchyma. In this way, leucine could potentially contribute to the synthesis of metabolites such as lipids, which require the withdrawal of citrate from the TCA cycle.

Cytochrome b561 Serves as a Potential Prognostic Biomarker and Target for Breast Cancer

PURPOSE

Cytochrome b561 (CYB561) is a transmembrane protein and participates in ascorbate recycling and iron homeostasis. However, its role in breast cancer remains unclear.

PATIENTS AND METHODS

In this study, we explored the expression pattern and prognostic value of CYB561 in breast cancer through The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), PrognoScan and Kaplan-Meier Plotter and confirmed its mRNA expression in human breast cell lines. LinkedOmics, Metascape and Gene Expression Profiling Interactive Analysis (GEPIA2) databases were applied to investigate the co-expression genes and construct microRNA (miRNA) networks associated with CYB561. The correlations between CYB561 and immune infiltration cells and genes were also illustrated.

RESULTS

The CYB561 expression was upregulated in breast cancer tissues and cell lines and significantly correlated with the clinical features of breast cancer patients. High CYB561 expression was associated with poor survival and was an independent risk factor for overall and disease-specific survival. Functional enrichment analysis showed that CYB561 and its co-expressed genes were mainly enriched in lipid biosynthetic process, Wnt signaling pathway, Hippo signaling pathway, etc. The miRNA network analysis suggested that hsa-miR-497 was negatively correlated with CYB561 expression and was predicted to direct target CYB561. CYB561 expression was positively correlated with infiltrating levels of CD4+ T cells, neutrophils and dendritic cells in breast cancer. Subsequent analysis found that B cells could predict the outcome of breast cancer. Also, CYB561 showed strong correlations with diverse immune marker sets in breast cancer.

CONCLUSION

CYB561 may serve as a potential prognostic biomarker and target for breast cancer. Our findings laid foundation for future research on molecular mechanisms of CYB561 in breast cancer.

Amino Acid Metabolism in Cancer Drug Resistance

Despite the numerous investigations on resistance mechanisms, drug resistance in cancer therapies still limits favorable outcomes in cancer patients. The complexities of the inherent characteristics of tumors, such as tumor heterogeneity and the complicated interaction within the tumor microenvironment, still hinder efforts to overcome drug resistance in cancer cells, requiring innovative approaches. In this review, we describe recent studies offering evidence for the essential roles of amino acid metabolism in driving drug resistance in cancer cells. Amino acids support cancer cells in counteracting therapies by maintaining redox homeostasis, sustaining biosynthetic processes, regulating epigenetic modification, and providing metabolic intermediates for energy generation. In addition, amino acid metabolism impacts anticancer immune responses, creating an immunosuppressive or immunoeffective microenvironment. A comprehensive understanding of amino acid metabolism as it relates to therapeutic resistance mechanisms will improve anticancer therapeutic strategies.

Prolactin: The Third Hormone in Breast Cancer

Prolactin coordinates with the ovarian steroids to orchestrate mammary development and lactation, culminating in nourishment and an increasingly appreciated array of other benefits for neonates. Its central activities in mammary epithelial growth and differentiation suggest that it plays a role(s) in breast cancer, but it has been challenging to identify its contributions, essential for incorporation into prevention and treatment approaches. Large prospective epidemiologic studies have linked higher prolactin exposure to increased risk, particularly for ER+ breast cancer in postmenopausal women. However, it has been more difficult to determine its actions and clinical consequences in established tumors. Here we review experimental data implicating multiple mechanisms by which prolactin may increase the risk of breast cancer. We then consider the evidence for role(s) of prolactin and its downstream signaling cascades in disease progression and treatment responses, and discuss how new approaches are beginning to illuminate the biology behind the seemingly conflicting epidemiologic and experimental studies of prolactin actions across diverse breast cancers.

Role of Branched-chain Amino Acid Metabolism in Tumor Development and Progression

Branched-chain amino acids (BCAAs), isoleucine, leucine and valine, are essential amino acids with vital roles in protein synthesis and energy production. We reviewed the fundamentals of BCAA metabolism in advanced cancer patients. BCAAs and various catabolic products act as signalling molecules, which activate mechanisms ranging from protein synthesis to insulin secretion. Recently, BCAA metabolism has been suggested to contribute to cancer progression. Of particular interest is the modulation of the mTOR activity by BCAAs. There are likely multiple pathways involved in BCAA metabolism implicated in carcinogenesis. Understanding the mechanism(s) underlying altered BCAAs metabolism will significantly advance the current understanding of nutrient involvement in carcinogenesis and direct future studies to unravel the significance of BCCA metabolites in tumor development and progression.