The combined expression of solute carriers is associated with a poor prognosis in highly proliferative ER+ breast cancer

Association of SLC12A1 and GLUR4 Ion Transporters with Neoadjuvant Chemoresistance in Luminal Locally Advanced Breast Cancer

Chemoresistance to standard neoadjuvant treatment commonly occurs in locally advanced breast cancer, particularly in the luminal subtype, which is hormone receptor-positive and represents the most common subtype of breast cancer associated with the worst outcomes. Identifying the genes associated with chemoresistance is crucial for understanding the underlying mechanisms and discovering effective treatments. In this study, we aimed to identify genes linked to neoadjuvant chemotherapy resistance in 62 retrospectively included patients with luminal breast cancer. Whole RNA sequencing of 12 patient biopsies revealed 269 differentially expressed genes in chemoresistant patients. We further validated eight highly correlated genes associated with resistance. Among these, solute carrier family 12 member 1 (SLC12A1) and glutamate ionotropic AMPA type subunit 4 (GRIA4), both implicated in ion transport, showed the strongest association with chemoresistance. Notably, SLC12A1 expression was downregulated, while protein levels of glutamate receptor 4 (GLUR4), encoded by GRIA4, were elevated in patients with a worse prognosis. Our results suggest a potential link between SLC12A1 gene expression and GLUR4 protein levels with chemoresistance in luminal breast cancer. In particular, GLUR4 protein could serve as a potential target for drug intervention to overcome chemoresistance.

Analysis of a new therapeutic target and construction of a prognostic model for breast cancer based on ferroptosis genes

Breast cancer, which is the most common malignant tumor among women worldwide and an important cause of death in women. The existing prognostic model for patients with breast cancer is not accurate as breast cancer is resistant to commonly used antitumor drugs. Ferroptosis is a novel mechanism of programmed cell death that depends on iron accumulation and lipid peroxidation. Various studies have confirmed the role of ferroptosis in tumor regulation and ferroptosis is now considered to play an important role in breast cancer development. At present, the association between breast cancer prognosis and ferroptosis-related gene expression remains unclear. Further exploration of this research area may optimize the evaluation and prediction of prognosis of patients with breast cancer and finding of new therapeutic targets. In this study, clinical factors and the expression of multiple genes were evaluated in breast cancer samples from the Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database database. Eleven prognostication-related genes (TP63, IFNG, MT3, ANO6, FLT3, PTGS2, SLC1A4, JUN, SLC7A5, CHAC1, and TF) were identified from differentially expressed genes to construct a survival prediction model, which showed a good prediction ability. KEGG pathway analysis revealed that immune-related pathways were the primary pathways. ssGSEA analysis showed significant differences in the distribution of certain immune-related cell subsets, such as CD8+T cells and B cells, and in the expression of multiple immune genes, including type II IFN response and APC coinhibition. In addition, 10 immune targets related to ferroptosis in breast cancer were found: CD276, CD80, HHLA2, LILRA2, NCR3LG1, NECTIN3, PVR, SLAMF9,TNFSF4, and BTN1A1. Using TCGA, new ferroptosis genes related to breast cancer prognosis were identified, a new reliable and accurate prognosis model was developed, and 10 new potential therapeutic targets different from the traditional targeted drugs were identified to provide a reference for improving the poor prognosis of patients with breast cancer.

SLC1A5 is a novel biomarker associated with ferroptosis and the tumor microenvironment: a pancancer analysis

Solute carrier family 1 member 5 (SLC1A5) is a member of the solute carrier (SLC) superfamily of transporters and plays an important role in tumors as a key transporter of glutamine into cells. However, the relationship between SLC1A5, which is involved in immune regulation, and immune cell infiltration in the tumor microenvironment has not been elucidated, and the relationship between SLC1A5 and ferroptosis is rarely reported. Therefore, we comprehensively analyzed the expression level of SLC1A5 across cancers and compared it with that in normal tissues. Then, the relationship between SLC1A5 expression and the tumor immune microenvironment was analyzed by single-cell analysis, gene set enrichment analysis (GSEA), and Tumor Immune Estimation Resource (TIMER). Next, the correlations of the SLC1A5 expression level with immunotherapy response, immunomodulator expression, tumor mutation burden (TMB) and microsatellite instability (MSI) were evaluated. Finally, in vitro experiments verified that SLC1A5 participates in ferroptosis of glioma cells to regulate tumor progression. Our results indicated that SLC1A5 is aberrantly expressed in most cancer types and closely associated with prognosis. The GSEA results showed that SLC1A5 is involved in immune activation processes and closely related to the infiltration levels of different immune cells in different cancer types. Upon further investigation, we found that SLC1A5 is a suppressor of ferroptosis in glioma, and SLC1A5 knockdown inhibited the proliferation and migration of glioma cells in vitro. In conclusion, we conducted a pancancer analysis of SLC1A5, demonstrated its role as a prognostic biomarker in cancer patients and explored its potential biological functions.

A novel exosome-derived prognostic signature and risk stratification for breast cancer based on multi-omics and systematic biological heterogeneity

Tumor heterogeneity remains a major challenge for disease subtyping, risk stratification, and accurate clinical management. Exosome-based liquid biopsy can effectively overcome the limitations of tissue biopsy, achieving minimal invasion, multi-point dynamic monitoring, and good prognosis assessment, and has broad clinical prospects. However, there is still lacking comprehensive analysis of tumor-derived exosome (TDE)-based stratification of risk patients and prognostic assessment for breast cancer with systematic dissection of biological heterogeneity. In this study, the robust corroborative analysis for biomarker discovery (RCABD) strategy was used for the identification of exosome molecules, differential expression verification, risk prediction modeling, heterogenous dissection with multi-ome (6101 molecules), our ExoBCD database (306 molecules), and 53 independent studies (481 molecules). Our results showed that a 10-molecule exosome-derived signature (exoSIG) could successfully fulfill breast cancer risk stratification, making it a novel and accurate exosome prognostic indicator (Cox P = 9.9E-04, HR = 3.3, 95% CI 1.6-6.8). Interestingly, HLA-DQB2 and COL17A1, closely related to tumor metastasis, achieved high performance in prognosis prediction (86.35% contribution) and accuracy (Log-rank P = 0.028, AUC = 85.42%). With the combined information of patient age and tumor stage, they formed a bimolecular risk signature (Clinmin-exoSIG) and a convenient nomogram as operable tools for clinical applications. In conclusion, as an extension of ExoBCD, this study conducted systematic analyses to identify prognostic multi-molecular panel and risk signature, stratify patients and dissect biological heterogeneity based on breast cancer exosomes from a multi-omics perspective. Our results provide an important reference for in-depth exploration of the "biological heterogeneity - risk stratification - prognosis prediction".

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.

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.

ALKBH family members as novel biomarkers and prognostic factors in human breast cancer

Breast cancer is the most common lethal carcinoma worldwide and better targeted therapies are still worthy of exploration, having had some great successes already. Abnormal expression of ALKBH members were found in various cancers, and the roles played by it were the focus of attention. The ALKBH gene family encodes nine homologous enzymes (ALKBH1-8 and FTO) to repair DNA or RNA depending on Fe2+ and α-ketoglutarate (α-KG), which is related to carcinogenesis. In this study, we applied several databases to explore the roles of ALKBHs in breast cancer. We found that ALKBH members were abnormal expression in breast cancer and associated with tumor stage and subclasses. Higher alteration rates of ALKBH family were found in breast cancer. Function enrichment revealed that several cancer-associated signal pathways were related to ALKBH family such as PI3K-Akt signaling pathway and axon guidance. Infiltration of immune cells (Eosinophiles, NK CD56bright cells, mast cells, T helper cells and so on) were strongly related to ALKBHs. Moreover, we further found that there was strong correlation between ALKBH7 and higher age, later T stage, ER/PR positive and post-menopause of breast cancer patients, and patients with higher ALKBH7 expression had shorter overall survival (OS) and post progression survival (PPS). In conclusion, our findings may provide novel insights into ALKBH-targeted therapy for breast cancer patients, and ALKBH7 may be a potential prognostic biomarker.

Bioinformatics Prediction and in vivo Verification Identify SLC7A5 as Immune Infiltration Related Biomarker in Breast Cancer

Purpose

Methods

Results

Conclusion

Inhibitor of glutamine metabolism V9302 promotes ROS-induced autophagic degradation of B7H3 to enhance antitumor immunity

Despite the enormous successes of anti-PD-1/PD-L1 immunotherapy in multiple other cancer types, the overall response rates of breast cancer remain suboptimal. Therefore, exploring additional immune checkpoint molecules for potential cancer treatment is crucial. B7H3, a T-cell coinhibitory molecule, is specifically overexpressed in breast cancer compared with normal breast tissue and benign lesions, making it an attractive therapeutic target. However, the mechanism by which B7H3 contributes to the cancer phenotype is unclear. Here we show that the expression of B7H3 is negatively related to the number of CD8+ T cells in breast tumor sites. In addition, analysis of the differentially expressed B7H3 reveals that it is inversely correlated to autophagic flux both in breast cancer cell lines and clinical tumor tissues. Furthermore, block of autophagy by bafilomycin A1 (Baf A1) increases B7H3 levels and attenuates CD8+ T cell activation, while promotion of autophagy by V9302, a small-molecule inhibitor of glutamine metabolism, decreases B7H3 expression and enhances granzyme B (GzB) production of CD8+ T cells via regulation of reactive oxygen species (ROS) accumulation. We demonstrate that combined treatment with V9302 and anti-PD-1 monoclonal antibody (mAb) enhances antitumor immunity in syngeneic mouse models. Collectively, our findings unveil the beneficial effect of V9302 in boosting antitumor immune response in breast cancer and illustrate that anti-PD-1 together with V9302 treatment may provide synergistic effects in the treatment of patients insensitive to anti-PD-1 therapy.

A comprehensive analysis of the diagnostic and prognostic value associated with the SLC7A family members in breast cancer

BACKGROUND

The solute carrier (SLC) 7 family genes play central roles in cancer cell metabolism as glucose and glutamate transporters. However, their expression and prognostic value in breast cancer (BC) remains to be elucidated.

METHODS

Clinical data from BC patients were downloaded from The Cancer Genome Atlas (TCGA) and the Kaplan-Meier (KM) plotter database. The mechanisms underlying the association between SLC7A expression and overall survival (OS) were explored using Cox regression and log-rank tests. ESTIMATE gives a measure of the immune-cell infiltrates. Single-sample (ss) Gene Set Enrichment Analysis (GSEA) was conducted to quantify immune cell infiltration.

RESULTS

High SLC7A5 expression was associated with a poorer survival time in BC patients according to the TCGA and KM plotter data. SLC7A4 was associated with good progression-free interval (PFI) and disease-specific survival (DSS) according to the TCGA data. Furthermore, SLC7A4 was correlated with good prognosis of OS, distant metastasis-free survival (DMFS), relapse-free survival (RFS), and post-progression survival (PPS) according to the KM plotter data. SLC7A3 expression was positively associated with OS, but was not strongly associated with PFI nor DSS in the TCGA data. However, SLC7A3 was positively correlated with DMFS and RFS in the KM database analysis. SLC7A had excellent diagnostic value in BC patients and was strongly correlated with tumor infiltration. T helper 2 (Th2) cells, CD56 bright natural killer (NK) cells, and NK cells were the most strongly correlated with the SLC7A family genes, suggesting that these genes play a crucial role in BC partly by modulating immune infiltration.

CONCLUSIONS

SLC7A4 and SLC7A5 expression levels may be sensitive biomarkers for predicting BC outcomes. SLC7A3 may be a potential diagnostic and prognostic biomarker in BC, but further studies are warranted to verify these results.

Identification of solute carrier family genes related to the prognosis and tumor-infiltrating immune cells of pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) has persisted as one of the worst prognostic tumors with a 5-year survival rate of lower than 6%. Although many studies have investigated PDAC, new biomarkers are required to ensure early diagnosis and predict the prognosis of PDAC.

Methods

In this study, we used bioinformatics methods to evaluate differences in the expression of solute carrier (SLC) family genes in tumors and non-tumors. A Kaplan-Meier analysis, least absolute shrinkage and selection operator (LASSO) analysis, and multivariate Cox proportional hazards regression analysis were used to evaluate the relationship between SLC genes and prognosis using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. The prognostic signature was constructed depending on the risk score to assess the impact of multiple genes on the prognosis, receiver operating characteristic (ROC) curves and forest plot was constructed to assess the ability to predict the prognosis and effects of clinical variables in both high- and low-risk groups. Tumor-infiltrating immune cells were evaluated using Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) in both high- and low-risk groups.

Results

In 32 SLC genes, 9 were significantly associated with the OS after LASSO analysis. SLC19A3 (P=0.007), SLC25A39 (P=0.027), SLC39A11 (P=0.043) were significantly associated with prognosis and included into the prognostic model. CIBERSORT demonstrated that memory B cells (P=0.004), naive B cells (P=0.007), CD8 T cells (P=0.003), activated memory CD4 T cells (P=0.004), and activated NK cells (P=0.019) were significantly higher in the low-risk group. Gene set enrichment analysis (GSEA) showed that potential molecular mechanisms enriched in MYC and p53 signaling pathways.

Conclusions

SLC19A3, SLC25A35, and SLC39A11 were significantly relative to the prognosis of PDAC and changed the tumor microenvironment, as well as the MYC and p53 signaling pathways. The SLC19A3 gene may represent a new tumor suppressor in PDAC.

SLC7A5 is linked to increased expression of genes related to proliferation and hypoxia in estrogen‑receptor‑positive breast cancer

The amino acid transporter named solute carrier family 7 member 5 (SLC7A5) is suggested to play a part in altered cell metabolism and proliferative signaling and has been reported to be overexpressed in various types of cancer, including breast cancer. Estrogen‑receptor‑positive (ER⁺) breast cancers constitute the most common type of breast malignancies and are often treated with anti‑estrogenic therapies. In this group of patients, endocrine resistance is a challenging problem that could lead to recurrent disease. To overcome this, additional prognostic biomarkers are needed. The present study aimed therefore to determine whether SLC7A5 may be considered as a possible prognostic marker in ER⁺ breast cancer and to investigate its relation with certain cancer‑related genes. We used a local breast cancer cohort (n=154) and immunohistochemistry to analyze the expression of SLC7A5 in association with clinicopathological characteristics and patient outcome. In addition, gene expression analysis was performed on 80 of these tumors. Furthermore, the METABRIC dataset was used for correlation analyses between expression of SLC7A5 and several genes related to breast cancer biology. The results demonstrated that overexpression of SLC7A5 was significantly associated with histopathological grade in patients with breast cancer, and that SLC7A5 mRNA expression was positively correlated with the expression of marker of proliferation Ki‑67 and hypoxia inducible factor 1 subunit alpha. Overexpression of SLC7A5 may therefore play a role in the biology of endocrinologically‑driven disease. However, when further assessing SLC7A5 using the METABRIC dataset, SLC7A5 mRNA expression level was more significantly increased in ER‑ subgroups compared with ER⁺ disease. All breast cancer subtypes included, SLC7A5 mRNA expression was correlated with a higher number of cancer‑related genes than in estrogen receptor positive tumors alone. The present study suggested that SLC7A5 expression may be of importance for breast cancer cell proliferation and survival. In order to further establish the biological and clinical role of SLC7A5 in breast cancer, further investigation using different breast cancer subgroups is required.

SLC34A2 Up-regulation And SLC4A4 Down-regulation Correlates With Invasion, Metastasis, And The MAPK Signaling Pathway In Papillary Thyroid Carcinomas

Papillary thyroid carcinoma (PTC) is one of the fastest growing endocrine system malignant carcinomas detected over the past decade. Unfortunately, more than 25% of PTC patients are characterized by their aggressiveness and subsequent metastasis; these characteristics usually indicate poor prognosis. Recently, increasing evidence has suggested that solute carrier (SLC) transporters may play a pivotal role in the initiation, invasion and metastasis of human carcinoma. However, the expression and clinicopathological significance of SLC transporters in patients with PTC remains undetermined. In this study, we aimed to elucidate how the differential expression of SLC transporters affects clinicopathological features, as well as determine the possible regulatory signaling pathways involved. Three differentially expressed SLC transporters were screened from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database using a bioinformatics approach. The results indicated that high SLC34A2 and low SLC4A4 protein expression exhibited a higher percentage of capsular invasion and extra-thyroid metastasis in patients. Logistic regression analysis showed that high SLC34A2 expression in tumors was identified as an independent risk factor for capsular invasion [odds ratio (OR)=11.400, 95% confidence interval (CI)=1.733-74.995, P=0.011] and extra-thyroid metastasis (OR=4.920, 95%CI=1.234-19.623, P=0.024), while low SLC4A4 expression in tumors was only identified as independent risk factors for extra-thyroid metastasis (OR=8.568, 95%CI =1.186-61.906, P=0.033). Specifically, for tumors with capsular invasion and extra-thyroid metastasis, the protein expression staining of SLC34A2 was markedly enhanced in the cytoplasm of follicular epithelial cells, contrastingly, SLC4A4 expression was notably weakened in the cytomembrane and nucleus. Intriguingly, both high SLC34A2 and low SLC4A4 protein expression were significantly linked to a high urinary iodine concentration in patients with PTC. Mechanistically, compared with adjacent normal thyroids, p-ERK was significantly up-regulated by 17.8% in the invading tumor; p-ERK, p-JNK, and p-P38 were markedly up-regulated by 29.2%, 67.1%, and 38.9% for metastatic tumors, respectively. Importantly, SLC4A4 negatively correlated with p-JNK (r=-0.696, P= 0.004) and p-P38 (r=-0.534, P=0.049). In conclusion, we suggest that up-regulated SLC34A2 (mainly in the cytoplasm) and down-regulated SLC4A4 (mainly in the cytomembrane and nucleus), which might be attributed to excess iodine intake, were closely linked to extra-thyroid metastasis in PTCs. Furthermore, this effect of SLC4A4 may be through the activation of JNK/P38 MAPK signaling pathway. Future in vivo and in vitro gain- or loss-of-function experiments are needed to verify these findings and further elucidate the deeper molecular mechanisms.

The Biological and Clinical Significance of Glutaminase in Luminal Breast Cancer

Simple Summary

Certain nutrients are needed by cancers to grow. Some breast cancers need the nutrient glutamine to grow and without it they don’t grow as quickly. In this study, we wanted to know the role of an enzyme, glutaminase, which is a substance produced by the body that breaks down glutamine so it can be used by cancers to grow. This enzyme occurs as two different types but we don’t know what their roles are in breast cancer. We therefore looked at the two types of enzyme in over 7000 breast cancers. We found that patients with high amounts of enzyme in early forms of breast cancer died earlier. Therefore, this enzyme has an important role in breast cancer and could be used to identify cancers which will get worse. We also think that using a drug to stop this enzyme will stop cancers growing. More studies are needed to confirm this.

Abstract

The glutamine metabolism has a key role in the regulation of uncontrolled tumour growth. This study aimed to evaluate the expression and prognostic significance of glutaminase in luminal breast cancer (BC). The glutaminase isoforms (GLS/GLS2) were assessed at genomic/transcriptomic levels, using METABRIC (n = 1398) and GeneMiner datasets (n = 4712), and protein using immunohistochemistry in well-characterised cohorts of Oestrogen receptor-positive/HER2-negative BC patients: ductal carcinoma in situ (DCIS; n = 206) and invasive breast cancer (IBC; n = 717). Glutaminase expression was associated with clinicopathological features, patient outcome and glutamine-metabolism-related genes. In DCIS, GLS alone and GLS+/GLS2- expression were risk factors for shorter local recurrence-free interval (p < 0.0001 and p = 0.001, respectively) and remained prognostic factors independent of tumour size, grade and comedo necrosis (p = 0.0008 and p = 0.003, respectively). In IBC, GLS gene copy number gain with high mRNA expression was associated with poor patient outcome (p = 0.011), whereas high GLS2 protein was predictive of a longer disease-free survival (p = 0.006). Glutaminase plays a role in the biological function of luminal BC, particularly GLS in the early non-invasive stage, which could be used as a potential biomarker to predict disease progression and a target for inhibition. Further validation is required to confirm these observations, and functional assessments are needed to explore their specific roles.

Immunotherapy using IgE or CAR T cells for cancers expressing the tumor antigen SLC3A2

Background

Cancer immunotherapy with monoclonal antibodies and chimeric antigen receptor (CAR) T cell therapies can benefit from selection of new targets with high levels of tumor specificity and from early assessments of efficacy and safety to derisk potential therapies.

Methods

Employing mass spectrometry, bioinformatics, immuno-mass spectrometry and CRISPR/Cas9 we identified the target of the tumor-specific SF-25 antibody. We engineered IgE and CAR T cell immunotherapies derived from the SF-25 clone and evaluated potential for cancer therapy.

Results

We identified the target of the SF-25 clone as the tumor-associated antigen SLC3A2, a cell surface protein with key roles in cancer metabolism. We generated IgE monoclonal antibody, and CAR T cell immunotherapies each recognizing SLC3A2. In concordance with preclinical and, more recently, clinical findings with the first-in-class IgE antibody MOv18 (recognizing the tumor-associated antigen Folate Receptor alpha), SF-25 IgE potentiated Fc-mediated effector functions against cancer cells in vitro and restricted human tumor xenograft growth in mice engrafted with human effector cells. The antibody did not trigger basophil activation in cancer patient blood ex vivo, suggesting failure to induce type I hypersensitivity, and supporting safe therapeutic administration. SLC3A2-specific CAR T cells demonstrated cytotoxicity against tumor cells, stimulated interferon-γ and interleukin-2 production in vitro. In vivo SLC3A2-specific CAR T cells significantly increased overall survival and reduced growth of subcutaneous PC3-LN3-luciferase xenografts. No weight loss, manifestations of cytokine release syndrome or graft-versus-host disease, were detected.

Conclusions

These findings identify efficacious and potentially safe tumor-targeting of SLC3A2 with novel immune-activating antibody and genetically modified cell therapies.

GEO data mining and TCGA analysis reveal altered branched chain amino acid metabolism in pancreatic cancer patients

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive tumor of the digestive system which has a less than 1% 5-year survival rate. The pathogenesis of PDAC development is incompletely understood. Genetic predisposition, disease history of chronic pancreatitis and diabetes elevate the risk of PDAC while environmental and dietary factors including smoking, alcohol abuse, high fat/protein intake as well as air pollution exacerbate PDAC progression. BCAAs, consisting of leucine, isoleucine and valine are essential amino acids that are obtained from food and play versatile roles in carcinogenesis. Recent studies have demonstrated that BCAA metabolism affects PDAC development but the results are controversial. To explore the possible engagement of BCAA metabolism in PDAC, we took advantage of the GEO and TCGA database and discovered that BCAA uptake is closely related to PDAC development while BCAA catabolism is down-regulated in PDAC tissue. Besides, NOTCH and MYC are differentially involved in BCAA metabolism in tumor and muscle, and enhanced lipid synthesis is independent of BCAA catabolism. Altogether, we highlight BCAA uptake as a promising target for PDAC treatment.

The role of the glutamine transporter ASCT2 in antineoplastic therapy

Cancer cells are metabolically reprogrammed to support their high rates of proliferation, continuous growth, survival, invasion, metastasis, and resistance to cancer treatments. Among changes in cancer cell bioenergetics, the role of glutamine metabolism has been receiving increasing attention. Increased glutaminolysis in cancer cells is associated with increased expression of membrane transporters that mediate the cellular uptake of glutamine. ASCT2 (Alanine, Serine, Cysteine Transporter 2) is a Na⁺-dependent transmembrane transporter overexpressed in cancer cells and considered to be the primary transporter for glutamine in these cells. The possibility of inhibiting ASCT2 for antineoplastic therapy is currently under investigation. In this article, we will present the pharmacological agents currently known to act on ASCT2, which have been attracting attention in antineoplastic therapy research. We will also address the impact of ASCT2 inhibition on the prognosis of some cancers. We conclude that ASCT2 inhibition and combination of ASCT2 inhibitors with other anti-tumor therapies may be a promising antineoplastic strategy. However, more research is needed in this area.

Increased expression of glutamine transporter SNAT2/SLC38A2 promotes glutamine dependence and oxidative stress resistance, and is associated with worse prognosis in triple-negative breast cancer

BACKGROUND

Glutamine (Gln) is an abundant nutrient used by cancer cells. Breast cancers cells and particularly triple-receptor negative breast cancer (TNBC) are reported to be dependent on Gln to produce the energy required for survival and proliferation. Despite intense research on the role of the intracellular Gln pathway, few reports have focussed on Gln transporters in breast cancer and TNBC.

METHODS

The role and localisation of the Gln transporter SLC38A2/SNAT2 in response to Gln deprivation or pharmacological stresses was examined in a panel of breast cancer cell lines. Subsequently, the effect of SLC38A2 knockdown in Gln-sensitive cell lines was analysed. The prognostic value of SLC38A2 in a cohort of breast cancer was determined by immunohistochemistry.

RESULTS

SLC38A2 was identified as a strongly expressed amino acid transporter in six breast cancer cell lines. We confirmed an autophagic route of degradation for SLC38A2. SLC38A2 knockdown decreased Gln consumption, inhibited cell growth, induced autophagy and led to ROS production in a subgroup of Gln-sensitive cell lines. High expression of SLC38A2 protein was associated with poor breast cancer specific survival in a large cohort of patients (p = 0.004), particularly in TNBC (p = 0.02).

CONCLUSIONS

These results position SLC38A2 as a selective target for inhibiting growth of Gln-dependent breast cancer cell lines.

LAT1 (SLC7A5) Overexpression in Negative Her2 Group of Breast Cancer: A Potential Therapy Target

Objective:

HER2 negative carcinomas of the breast pose a challenge for treatment due to redundancies in potential drug targets and poor patient outcomes. Our aim was to investigate the role of L-type amino acid transporter – LAT1 as a potential prognosticator and a drug target.

Methods:

In this retrospective work, we have studied the expression of LAT1 in 145 breast cancer tissues via immunohistochemistry. Overall survival analysis was used to evaluate patient outcome in various groups of our cohort.

Results:

Positive LAT1 expression was found in 27 (84.4%) luminal A subtype, 27 (64.3%) luminal B/triple positive subtype, 29 (82.9%) triple negative subtype, and 24 (66.7%) HER2-only positive subtype (p=0.1). Interestingly, negative correlation was found between LAT1 and HER2; where positive expression of LAT1 was found in 56 (83.6%) cases in negative HER2 group and 51 (65.4%) cases from positive HER2 group (p=0.01). Unfortunately, we were unable to report significant survival differences when LAT1 expression was studied in the negative HER2 group. Nevertheless, five incidents of mortality (out of 55) were reported in LAT1+/HER2- group compared to none in the LAT1-/HER2- group (N=11).

Conclusion:

Our findings of overexpression of LAT1 in negative HER2 group suggest a role of this protein as prognosticator and drug target in a challenging therapeutic cohort.

Enhanced glutamine uptake influences composition of immune cell infiltrates in breast cancer

Background

Cancer cells must alter their metabolism to support proliferation. Immune evasion also plays a role in supporting tumour progression. This study aimed to find whether enhanced glutamine uptake in breast cancer (BC) can derive the existence of specific immune cell subtypes, including the subsequent impact on patient outcome.

Methods

SLC1A5, SLC7A5, SLC3A2 and immune cell markers CD3, CD8, FOXP3, CD20 and CD68, in addition to PD1 and PDL1, were assessed by using immunohistochemistry on TMAs constructed from a large BC cohort (n = 803). Patients were stratified based on SLC protein expression into accredited clusters and correlated with immune cell infiltrates and patient outcome. The effect of transient siRNA knockdown of SLC7A5 and SLC1A5 on PDL1 expression was evaluated in MDA-MB-231 cells.

Results

High SLCs were significantly associated with PDL1 and PD1 +, FOXP3 +, CD68 + and CD20 + cells (p < 0.001). Triple negative (TN), HER2 + and luminal B tumours showed variable associations between SLCs and immune cell types (p ≤ 0.04). The expression of SLCs and PDL1, PD1 +, FOXP3 + and CD68 + cells was associated with poor patient outcome (p < 0.001). Knockdown of SLC7A5 significantly reduced PDL1 expression.

Conclusion

This study provides data that altered glutamine pathways in BC that appears to play a role in deriving specific subtypes of immune cell infiltrates, which either support or counteract its progression.

Proteomic analysis of the intestine reveals SNARE-mediated immunoregulatory and amino acid absorption perturbations in a rat model of depression

AIMS

To clarify the role of the gut-brain axis in depression.

MAIN METHODS

We used the iTRAQ technique to identify differential proteins in the intestine of the rat model of chronic unpredictable mild stress (CUMS)-induced depression. Significant differential proteins were subjected to Gene Ontology (GO) functional annotations and KEGG pathway enrichment analysis. Key proteins were validated at the mRNA and protein levels. The levels of cytokines in the intestine, serum and hypothalamus were examined by ELISA. HPLC-UV was used to detect the levels of amino acids.

KEY FINDINGS

In the rat intestine, 349 differential proteins (209 downregulated, 140 upregulated) were identified. GO analysis indicated that "protein complex assembly" was the first-ranked biological process. SNARE complex components, including SNAP23, VAMP3 and VAMP8, were increased at the mRNA levels, while only VAMP3 and VAMP8 were also upregulated at the protein level. TNFα, IL6 and IL1β were upregulated in the CUMS rat intestine, while TNFα was decreased in the serum and hypothalamus. IL1β was decreased in the serum. "Protein digestion and absorption" was the most significantly enriched KEGG pathway, involving 5 differential proteins: SLC9A3, ANPEP, LAT1, ASCT2 and B⁰AT1. Glutamine, glycine and aspartic acid were perturbed in the CUMS rat intestine.

SIGNIFICANCE

Our findings suggest that CUMS enhances the adaptive immune response in the intestine through ER-phagosome pathway mediated by SNARE complex and disturb absorption of amino acids. It advances our understanding of the role of gut-brain axis in depression and provides a potential therapeutic target for the disease.

Proteomic analysis of meningiomas reveals clinically distinct molecular patterns

BACKGROUND

Meningiomas represent one of the most common brain tumors and exhibit a clinically heterogeneous behavior, sometimes difficult to predict with classic histopathologic features. While emerging molecular profiling efforts have linked specific genomic drivers to distinct clinical patterns, the proteomic landscape of meningiomas remains largely unexplored.

METHODS

We utilize liquid chromatography tandem mass spectrometry with an Orbitrap mass analyzer to quantify global protein abundances of a clinically well-annotated formalin-fixed paraffin embedded (FFPE) cohort (n = 61) of meningiomas spanning all World Health Organization (WHO) grades and various degrees of clinical aggressiveness.

RESULTS

In total, we quantify 3042 unique proteins comparing patterns across different clinical parameters. Unsupervised clustering analysis highlighted distinct proteomic (n = 106 proteins, Welch's t-test, P < 0.01) and pathway-level (eg, Notch and PI3K/AKT/mTOR) differences between convexity and skull base meningiomas. Supervised comparative analyses of different pathological grades revealed distinct patterns between benign (grade I) and atypical/malignant (grades II‒III) meningiomas with specific oncogenes enriched in higher grade lesions. Independent of WHO grade, clinically aggressive meningiomas that rapidly recurred (<3 y) had distinctive protein patterns converging on mRNA processing and impaired activation of the matrisome complex. Larger sized meningiomas (>3 cm maximum tumor diameter) and those with previous radiation exposure revealed perturbed pro-proliferative (eg, epidermal growth factor receptor) and metabolic as well as inflammatory response pathways (mitochondrial activity, interferon), respectively.

CONCLUSIONS

Our proteomic study demonstrates that meningiomas of different grades and clinical parameters present distinct proteomic profiles. These proteomic variations offer potential future utility in helping better predict patient outcome and in nominating novel therapeutic targets for personalized care.