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

Patient-derived organotypic tissue cultures as a platform to evaluate metabolic reprogramming in breast cancer patients

Patient-derived organotypic tissue cultures (PD-OTC) are unique models for probing cancer metabolism and therapeutic responses. They retain patient tissue architectures/microenvironments that are difficult to recapitulate while affording comparison of cancer (CA) versus matched noncancer (NC) tissue responses to treatments. We have developed a long-term culturing method for fresh and cryopreserved PD-OTC of breast cancer patients bearing invasive ductal carcinoma. Five PD-OTC came from patients with treatment-naïve primary ER+/PR+/HER2- tumors while one came from a patient with neoadjuvant therapy for locally metastatic ERlow/PR-/HER2- tumor. They all exhibited tissue outgrowth in 1 month with some CA OTC harboring isolatable organoids and fibroblasts. We interrogated reprogrammed metabolism in CA versus paired NC OTC with dual 2H7-glucose/13C5,15N2-Gln tracers coupled with stable isotope-resolved metabolomic analysis. We noted variable activation of glycolysis, cataplerotic/anaplerotic Krebs cycle including reductive carboxylation, the pentose phosphate pathway, riboneogenesis, gluconeogenesis, de novo and salvage synthesis of purine/pyrimidine nucleotides, and ADP-ribosylation in CA PD-OTC. Altered metabolic activities were in part accountable by expression changes in key enzymes measured by reverse phase protein array profiling. Notably, Gln-fueled gluconeogenesis products were preferentially diverted to support purine nucleotide synthesis. When blocking this novel process with an inhibitor of phosphoenolpyruvate carboxykinase (3-mercaptopicolinic acid), metastatic, ERlow/PR-/HER2- CA OTC displayed compromised cellularity, reduced outgrowth, and disrupted growth/survival-supporting metabolism but the matched NC OTC did not. Thus, our PD-OTC culturing method not only promoted understanding of actual patient's tumor metabolism to uncover viable metabolic targets but also enabled target testing and elucidation of therapeutic efficacy.

Systemic therapy for pretreated advanced biliary tract cancer: past developments and recent advances

Biliary tract cancer (BTC) remains among the most challenging malignancies with a poor prognosis and limited treatment options, particularly in pretreated patients. As most patients experience disease progression after first-line treatment, effective second-line and subsequent treatments are required. Although the addition of modified FOLFOX (fluorouracil, leucovorin, and oxaliplatin) to active symptom control improved the overall survival of patients with progressing advanced BTC despite gemcitabine plus cisplatin treatment, its efficacy was modest. Moreover, most clinical trials demonstrated modest efficacy of molecular-targeted agents for molecularly unselected pretreated advanced BTC. Patients with advanced BTC carry a relatively high druggable genetic alteration rate and have shown promising responses to molecular-matched therapies targeting gene alterations such as FGFR2 fusions/rearrangements, IDH1 mutation, and HER2 overexpression/amplification. Additionally, tumor-agnostic approaches, including BRAF V600E, NTRK fusion, and RET fusion, have expanded the treatment options for some patients. Immune checkpoint inhibitors have shown limited efficacy as mono- or combination therapy in patients with pretreated advanced BTC. Therefore, developmental efforts have shifted to immune checkpoint inhibitor and other combinations such as vascular endothelial growth factor receptor inhibitors or radiation. In addition to refining combination strategies to enhance the therapeutic potential of immune checkpoint inhibitor, future research should focus on elucidating the tumor microenvironment. This review delineates the evolution of systemic therapies in patients with pretreated advanced BTC. By examining past developments and recent advances through prospective trials, it highlights novel approaches that may improve outcomes in this challenging disease.

LncRNA TCL6 regulates miR-876-5p/MYL2 axis to suppress breast cancer progression

We explored the influence of the TCL6/miR-876-5p axis on breast cancer cell proliferation and migration. Using The Cancer Genome Atlas (TCGA) database, we evaluated the expression of TCL6 in breast cancer patients and studied its effects on cell proliferation, migration, and the cell cycle in vitro. The regulatory effect of miR-876-5p on myosin light chain-2 (MYL2) 3' untranslated regions (3'UTR) was analyzed through luciferase reporter assays, and rescue experiments confirmed TCL6-driven upregulation of MYL2 via a competitive RNA binding mechanism. Furthermore, we used a mouse subcutaneous tumor model to assess the impact of TCL6 knockdown combined with immune checkpoint blockade therapy. Our results indicated that higher TCL6 expression correlated with a favorable prognosis in breast cancer patients. In vitro experiments showed that knockdown of TCL6 and MYL2 enhanced breast cancer cell proliferation and migration. The luciferase and rescue assays demonstrated that TCL6 interacted with miR-876-5p to upregulate MYL2, thereby inhibiting cell proliferation and migration. Both in vitro and in vivo studies revealed that overexpression of TCL6 suppressed tumor growth and improved the response to PD-1 immunotherapy in tumor-bearing mice. This research highlights the pivotal role of lncRNA TCL6 in breast cancer development via a ceRNA network involving miR-876-5p and MYL2, suggesting a novel molecular target for breast cancer therapy.

N-acetyltransferase 10 Promotes Cervical Cancer Progression Via N4-acetylation of SLC7A5 mRNA

INTRODUCTION

N-acetyltransferase 10 (NAT10) mediates N4-acetylcytidine (ac4C) mRNA modification and promotes malignant tumor progression. However, there has been limited research on its role in cervical cancer. This study aimed to decipher the role of NAT10 in cervical cancer.

METHODS

The prognostic value of NAT10 was explored using the cancer genome atlas (TCGA) database and immunohistochemistry of cervical cancer tissue. The biological actions of NAT10 in cervical cancer were investigated by cell proliferation, transwell, wound healing, and chicken chorioallantoic membrane assays. The therapeutic action of remodelin (a NAT10 inhibitor) was verified in a nude mouse model. Mechanistic analyses were conducted by RNA sequencing, ac4C dot blotting, acetylated RNA immunoprecipitation, quantitative PCR, and RNA stability experiments.

RESULTS

NAT10 was overexpressed in cervical carcinoma and its overexpression was associated with poor prognosis. NAT10 knockout impaired proliferative and metastatic potentials of cervical cancer cells, while its overexpression had the opposite effects. Remodelin impaired cervical cancer proliferation in vivo and in vitro. NAT10 acetylated solute carrier family 7 member 5 (SLC7A5) enhanced mRNA stability to regulate SLC7A5 expression.

CONCLUSIONS

NAT10 exerts a critical role in cervical cancer progression via acetylating SLC7A5 mRNA and could represent a key prognostic and therapeutic target in cervical cancer.

Characterization of Immune Landscape Based on Homologous Recombination Deficiency Associated Signatures and Identification of Knockdown of ERCC6L to Promote Radiosensitivity in Breast Cancer

BACKGROUND

Homologous recombination deficiency (HRD) exhibits significant associations with the occurrence, progression, and prognosis of breast cancer. However, the primary breast cancer HRD positivity rate is merely 24%. The identification of markers associated with HRD is crucial for the development of novel therapeutic approaches for breast cancer. The role of the oncogene ERCC6L in breast cancer remains unclear, and its interaction with radiotherapy has yet to be explored, necessitating further investigation for clarification.

METHODS

We employed WGCNA to identify genes associated with the HRD score, utilizing public HRD score and genetic data from TCGA breast cancer, with their clinical characteristics. Subsequently, we employed various machine learning methods to filter relevant genes. The final four genes were obtained through random forest and stepCox, and their performance was validated in TCGA, GSE96058, and METABRIC datasets. Next, we assessed the tumor immune microenvironment using methods such as ssGSEA, GSVA, CIBERSORT, ESTIMATE, and single-cell analysis. Finally, we validated the downregulation of ERCC6L, increasing DNA damage and enhancing radiation sensitivity, through immune fluorescence, flow cytometry, plate cloning, and western blot.

RESULTS

A prognostic model named HRAS was established through machine learning, consisting of four genes (ERCC6L, UBE2T, TPX2, and SLC7A5). The indicator exhibited excellent predictive performance on the prognosis and the efficacy of immunotherapy and radiotherapy of breast cancer patients in independent datasets. Breast cancer patients with high HRAS scores showed higher TMB and stemness, increased expression of immune checkpoints, reduced immune cell infiltration, and poorer prognosis in the context of immunotherapy and radiotherapy. Experimental validation demonstrated that knockdown of ERCC6L markedly elevated DNA damage, enhanced apoptosis, and induced cell cycle arrest in response to radiation therapy, thereby sensitizing cells to radiation.

CONCLUSION

The HRD-related signatures displayed strong predictive capabilities for the prognosis in multiple datasets and the efficacy of immunotherapy and radiotherapy of breast cancer patients. Moreover, the composite indicator reflected the immune microenvironment characteristics and could be novel markers for predicting the prognosis and clinical treatment outcomes in breast cancer patients. Our experiments first elucidated the role of ERCC6L in enhancing radiation-induced DNA damage, presenting a novel target for strategies aimed at sensitizing cancer cells to radiotherapy.

Exploring the role of metabolic pathways in TNBC immunotherapy: insights from single-cell and spatial transcriptomics

The article provides an overview of the current understanding of the interplay between metabolic pathways and immune function in the context of triple-negative breast cancer (TNBC). It highlights recent advancements in single-cell and spatial transcriptomics technologies, which have revolutionized the analysis of tumor heterogeneity and the immune microenvironment in TNBC. The review emphasizes the crucial role of metabolic reprogramming in modulating immune cell function, discussing how specific metabolic pathways, such as glycolysis, lipid metabolism, and amino acid metabolism, can directly impact the activity and phenotypes of various immune cell populations within the TNBC tumor microenvironment. Furthermore, the article explores the implications of these metabolic-immune interactions for the efficacy of immune checkpoint inhibitor (ICI) therapies in TNBC, suggesting that strategies targeting metabolic pathways may enhance the responsiveness to ICI treatments. Finally, the review outlines future directions and the potential for combination therapies that integrate metabolic modulation with immunotherapeutic approaches, offering promising avenues for improving clinical outcomes for TNBC patients.

Integration of machine learning and experimental validation to identify the prognostic signature related to diverse programmed cell deaths in breast cancer

Background

Programmed cell death (PCD) is closely related to the occurrence, development, and treatment of breast cancer. The aim of this study was to investigate the association between various programmed cell death patterns and the prognosis of breast cancer (BRCA) patients.

Methods

The levels of 19 different programmed cell deaths in breast cancer were assessed by ssGSEA analysis, and these PCD scores were summed to obtain the PCDS for each sample. The relationship of PCDS with immune as well as metabolism-related pathways was explored. PCD-associated subtypes were obtained by unsupervised consensus clustering analysis, and differentially expressed genes between subtypes were analyzed. The prognostic signature (PCDRS) were constructed by the best combination of 101 machine learning algorithm combinations, and the C-index of PCDRS was compared with 30 published signatures. In addition, we analyzed PCDRS in relation to immune as well as therapeutic responses. The distribution of genes in different cells was explored by single-cell analysis and spatial transcriptome analysis. Potential drugs targeting key genes were analyzed by Cmap. Finally, the expression levels of key genes in clinical tissues were verified by RT-PCR.

Results

PCDS showed higher levels in cancer compared to normal. Different PCDS groups showed significant differences in immune and metabolism-related pathways. PCDRS, consisting of seven key genes, showed robust predictive ability over other signatures in different datasets. The high PCDRS group had a poorer prognosis and was strongly associated with a cancer-promoting tumor microenvironment. The low PCDRS group exhibited higher levels of anti-cancer immunity and responded better to immune checkpoint inhibitors as well as chemotherapy-related drugs. Clofibrate and imatinib could serve as potential small-molecule complexes targeting SLC7A5 and BCL2A1, respectively. The mRNA expression levels of seven genes were upregulated in clinical cancer tissues.

Conclusion

PCDRS can be used as a biomarker to assess the prognosis and treatment response of BRCA patients, which offers novel insights for prognostic monitoring and treatment personalization of BRCA patients.

Leucine restriction ameliorates Fusobacterium nucleatum-driven malignant progression and radioresistance in nasopharyngeal carcinoma

Radiotherapy resistance is the main cause of treatment failure among patients with nasopharyngeal carcinoma (NPC). Recently, increasing evidence has linked the presence of intratumoral Fusobacterium nucleatum (Fn) with the malignant progression and therapeutic resistance of multiple tumor types, but its influence on NPC has remained largely unknown. We found that Fn is prevalent in the tumor tissue of patients with NPC and is associated with radioresistance. Fn invaded and proliferated inside NPC cells and aggravated tumor progression. Mechanistically, Fn slowed mitochondrial dysfunction by promoting mitochondrial fusion and decreasing ROS generation, preventing radiation-induced oxidative damage. Fn inhibited PANoptosis by the SLC7A5/leucine-mTORC1 axis during irradiation stress, thus promoting radioresistance. Treatment with the mitochondria-targeted antibiotics or dietary restriction of leucine reduced intratumoral Fn load, resensitizing tumors to radiotherapy in vivo. These findings demonstrate that Fn has the potential to be a predictive marker for radioresistance and to help guide individualized treatment for patients with NPC.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Quantitative analysis of non-histone lysine methylation sites and lysine demethylases in breast cancer cell lines

Growing evidence shows that lysine methylation is a widespread protein post-translational modification that regulates protein function on histone and non-histone proteins. Numerous studies have demonstrated that dysregulation of lysine methylation mediators contributes to cancer growth and chemotherapeutic resistance. While changes in histone methylation are well documented with extensive analytical techniques available, there is a lack of high-throughput methods to reproducibly quantify changes in the abundances of the mediators of lysine methylation and non-histone lysine methylation (Kme) simultaneously across multiple samples. Recent studies by our group and others have demonstrated that antibody enrichment is not required to detect lysine methylation, prompting us to investigate the use of Tandem Mass Tag (TMT) labeling for global Kme quantification sans antibody enrichment in four different breast cancer cell lines (MCF-7, MDA-MB-231, HCC1806, and MCF10A). To improve the quantification of KDMs, we incorporated a lysine demethylase (KDM) isobaric trigger channel, which enabled 96% of all KDMs to be quantified while simultaneously quantifying 326 Kme sites. Overall, 142 differentially abundant Kme sites and eight differentially abundant KDMs were identified between the four cell lines, revealing cell line-specific patterning.

Identification of the novel exhausted T cell CD8 + markers in breast cancer

Cancer is one of the most concerning public health issues and breast cancer is one of the most common cancers in the world. The immune cells within the tumor microenvironment regulate cancer development. In this study, single immune cell data sets were used to identify marker gene sets for exhausted CD8 + T cells (CD8Tex) in breast cancer. Machine learning methods were used to cluster subtypes and establish the prognostic models with breast cancer bulk data using the gene sets to evaluate the impacts of CD8Tex. We analyzed breast cancer overexpressing and survival-associated marker genes and identified CD8Tex hub genes in the protein-protein-interaction network. The relevance of the hub genes for CD8 + T-cells in breast cancer was evaluated. The clinical associations of the hub genes were analyzed using bulk sequencing data and spatial sequencing data. The pan-cancer expression, survival, and immune association of the hub genes were analyzed. We identified biomarker gene sets for CD8Tex in breast cancer. CD8Tex-based subtyping systems and prognostic models performed well in the separation of patients with different immune relevance and survival. CRTAM, CLEC2D, and KLRB1 were identified as CD8Tex hub genes and were demonstrated to have potential clinical relevance and immune therapy impact. This study provides a unique view of the critical CD8Tex hub genes for cancer immune therapy.

Characterizations of multi-kingdom gut microbiota in immune checkpoint inhibitor-treated hepatocellular carcinoma

BACKGROUND

The association between gut bacteria and the response to immune checkpoint inhibitors (ICI) in hepatocellular carcinoma (HCC) has been studied; however, multi-kingdom gut microbiome alterations and interactions in ICI-treated HCC cohorts are not fully understood.

METHODS

From November 2018 to April 2022, patients receiving ICI treatment for advanced HCC were prospectively enrolled. Herein, we investigated the multi-kingdom microbiota characterization of the gut microbiome, mycobiome, and metabolome using metagenomic, ITS2, and metabolomic data sets of 80 patients with ICI-treated HCC.

RESULTS

Our findings demonstrated that bacteria and metabolites differed significantly between the durable clinical benefit (DCB) and non-durable clinical benefit (NDB) groups, whereas the differences were smaller for fungi. The overall diversity of bacteria and fungi before treatment was higher in the DCB group than in the NDB group, and the difference in diversity began to change with the use of immunotherapy after 6-8 weeks. We also explored the alterations of gut microbes in the DCB and NDB groups, established 18 bacterial species models as predictive biomarkers for predicting whether immunotherapy is of sustained benefit (area under the curve=75.63%), and screened two species of bacteria (Actinomyces_sp_ICM47, and Senegalimassilia_anaerobia) and one metabolite (galanthaminone) as prognostic biomarkers for predicting survival in patients with HCC treated with ICI.

CONCLUSIONS

In this study, the status and characterization of the multi-kingdom microbiota, including gut bacteria, fungi, and their metabolites, were described by multiomics sequencing for the first time in patients with HCC treated with ICI. Our findings demonstrate the potential of bacterial taxa as predictive biomarkers of ICI clinical efficacy, and bacteria and their metabolites as prognostic biomarkers.

SLC7A5 correlated with malignancies and immunotherapy response in bladder cancer

BACKGROUND

Metabolic reprogramming contributes to bladder cancer development. This study aimed to understand the role of SLC7A5 in bladder cancer.

METHODS

We systematically analyzed the correlation between SLC7A5 and bladder cancer through various approaches, including bioinformatics, western blotting, cell cycle analysis, cell proliferation assays, and invasion experiments. We also investigated the immunological features within the tumor microenvironment (TME), encompassing cancer immune cycles, immune modulators, immune checkpoints, tumor-infiltrating immune cells (TIIC), T cell inflammation scores, and treatment responses. Additionally, for a comprehensive assessment of the expression patterns and immunological roles of SLC7A5, pan-cancer analysis was performed using cancer genomics datasets.

RESULTS

SLC7A5 was associated with adverse prognosis in bladder cancer patients, activating the Wnt pathway and promoting bladder cancer cell cycle progression, proliferation, migration, and invasion. Based on the evidence that SLC7A5 positively correlated with immunomodulators, TIIC, the cancer immune cycle, immune checkpoint and T cell inflammation scores, we also found that SLC7A5 was associated with the inflammatory tumor immune microenvironment. EGFR-targeted therapy, cancer immunotherapy, and radiation therapy were effective for patients with high SLC7A5 expression in bladder cancer. Low SLC7A5 patients were, however, sensitive to targeted therapies and anti-angiogenic therapy, such as blocking β-catenin network, PPAR-γ and FGFR3 signaling. Anti-SLC7A5 combined with cancer immunotherapy may have greater effectiveness than either therapy alone. Furthermore, we observed specific overexpression of SLC7A5 in TME of various cancers.

CONCLUSION

SLC7A5 can predict therapeutic response to immunotherapy, radiotherapy and chemotherapy in bladder cancer patients. Targeting SLC7A5 in combination with immunotherapy may be a potentially appropriate treatment option.

Identification of hub glutamine metabolism-associated genes and immune characteristics in pre-eclampsia

OBJECTIVE

Preeclampsia (PE) is a severe complication of unclear pathogenesis associated with pregnancy. This research aimed to elucidate the properties of immune cell infiltration and potential biomarkers of PE based on bioinformatics analysis.

MATERIALS AND METHODS

Two PE datasets were imported from the Gene ExpressioOmnibus (GEO) and screened to identify differentially expressed genes (DEGs). Significant module genes were identified by weighted gene co-expression network analysis (WGCNA). DEGs that interacted with key module genes (GLu-DEGs) were analyzed further by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses. The diagnostic value of the genes was assessed using receiver operating characteristic (ROC) curves and protein-protein interaction (PPI) networks were constructed using GeneMANIA, and GSVA analysis was performed using the MSigDB database. Immune cell infiltration was analyzed using the TISIDB database, and StarBase and Cytoscape were used to construct an RBP-mRNA network. The identified hub genes were validated in two independent datasets. For further confirmation, placental tissue from healthy pregnant women and women with PE were collected and analyzed using both RT-qPCR and immunohistochemistry.

RESULTS

A total of seven GLu-DEGs were obtained and were found to be involved in pathways associated with the transport of sulfur compounds, PPAR signaling, and energy metabolism, shown by GO and KEGG analyses. GSVA indicated significant increases in adipocytokine signaling. Furthermore, single-sample Gene Set Enrichment Analysis (ssGSEA) indicated that the levels of activated B cells and T follicular helper cells were significantly increased in the PE group and were negatively correlated with GLu-DEGs, suggesting their potential importance.

CONCLUSION

In summary, the results showed a correlation between glutamine metabolism and immune cells, providing new insights into the understandingPE pathogenesis and furnishing evidence for future advances in the treatment of this disease.

A glutamine tug-of-war between cancer and immune cells: recent advances in unraveling the ongoing battle

Glutamine metabolism plays a pivotal role in cancer progression, immune cell function, and the modulation of the tumor microenvironment. Dysregulated glutamine metabolism has been implicated in cancer development and immune responses, supported by mounting evidence. Cancer cells heavily rely on glutamine as a critical nutrient for survival and proliferation, while immune cells require glutamine for activation and proliferation during immune reactions. This metabolic competition creates a dynamic tug-of-war between cancer and immune cells. Targeting glutamine transporters and downstream enzymes involved in glutamine metabolism holds significant promise in enhancing anti-tumor immunity. A comprehensive understanding of the intricate molecular mechanisms underlying this interplay is crucial for developing innovative therapeutic approaches that improve anti-tumor immunity and patient outcomes. In this review, we provide a comprehensive overview of recent advances in unraveling the tug-of-war of glutamine metabolism between cancer and immune cells and explore potential applications of basic science discoveries in the clinical setting. Further investigations into the regulation of glutamine metabolism in cancer and immune cells are expected to yield valuable insights, paving the way for future therapeutic interventions.

Breaking Barriers: The Promise and Challenges of Immune Checkpoint Inhibitors in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly aggressive malignancy with pronounced immunogenicity, exhibiting rapid proliferation and immune cell infiltration into the tumor microenvironment. TNBC's heterogeneity poses challenges to immunological treatments, inducing resistance mechanisms in the tumor microenvironment. Therapeutic modalities, including immune checkpoint inhibitors (ICIs) targeting PD-1, PD-L1, and CTLA-4, are explored in preclinical and clinical trials. Promising results emerge from combining ICIs with anti-TGF-β and VISTA, hindering TNBC tumor growth. TNBC cells employ complex evasion strategies involving interactions with stromal and immune cells, suppressing immune recognition through various cytokines, chemokines, and metabolites. The recent focus on unraveling humoral and cellular components aims to disrupt cancer crosstalk within the tumor microenvironment. This review identifies TNBC's latest resistance mechanisms, exploring potential targets for clinical trials to overcome immune checkpoint resistance and enhance patient survival rates.