Suppression of the SLC7A11/glutathione axis causes synthetic lethality in KRAS-mutant lung adenocarcinoma

The amino acid transporter SLC7A11 expression in breast cancer

Breast cancer (BC), characterized by its diverse molecular profiles and clinical outcomes, presents a significant challenge in the development of effective therapeutic strategies. Metabolic reprogramming, a defining characteristic of cancer, has emerged as a promising target for novel therapies. SLC7A11, an amino acid transporter that facilitates cysteine uptake in exchange for glutamate, plays a crucial role in sustaining the altered metabolism of cancer cells. This study delves into the comprehensive analysis of SLC7A11 at the genomic, transcriptomic, and protein levels in extensive BC datasets to elucidate its potential role in different BC subtypes. SLC7A11 gene copy number and mRNA expression were evaluated using the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohort (n = 1,980) and Breast Cancer Gene Expression Miner (n = 4,712). SLC7A11 protein was assessed using immunohistochemistry in a large BC cohort (n = 1,981). Additionally, The Cancer Genome Atlas (TCGA) dataset was used to explore SLC7A11 DNA methylation patterns using MethSurv (n = 782) and association of SLC7A11 mRNA expression with immune infiltrates using TIMER (n = 1,100). High SLC7A11 mRNA and SLC7A11 protein expression were significantly associated with high tumor grade (p ≤ .02), indicating a potential role in cancer progression. Interestingly, SLC7A11 copy number gain was observed in HER2+ tumors (p = .01), suggesting a subtype-specific association. In contrast, SLC7A11 mRNA expression was higher in the basal-like/triple-negative (TN; p < .001) and luminal B tumors (p = .02), highlighting its differential expression across BC subtypes. Notably, high SLC7A11 protein expression was predominantly observed in Estrogen Receptor (ER)-negative and Triple Negative (TN) BC, suggesting a role in these aggressive subtypes. Further analysis revealed that SLC7A11 was positively correlated with other amino acid transporters and enzymes associated with glutamine metabolism, implying a coordinated role in metabolic regulation. Additionally, SLC7A11 gene expression was positively associated with neutrophil and macrophage infiltration, suggesting a potential link between SLC7A11 and tumor immunity. Our findings suggest that SLC7A11 plays a significant role in BC metabolism, demonstrating differential expression across subtypes and associations with poor patient outcomes. Further functional studies are warranted to elucidate the precise mechanisms by which SLC7A11 contributes to BC progression and to explore its potential as a therapeutic target.

AQP4-AS1 Can Regulate the Expression of Ferroptosis-Related Regulator ALOX15 through Competitive Binding with miR-4476 in Lung Adenocarcinoma

Background  The AQP4-AS1/miR-4476-ALOX15 regulatory axis was discovered in previous studies. We aimed to investigate the regulatory mechanism of the ferroptosis-related regulator ALOX15 by AQP4-AS1 and miR-4476 in lung adenocarcinoma (LUAD) and find new targets for clinical treatment. Methods  After bioinformatics analysis, we contained one ferroptosis-related gene (FRG), namely ALOX15. MicroRNAs (miRNAs) and long noncoding RNAs were predicted by miRWalk. Furthermore, we constructed overexpressed LUAD cell lines. Real-time quantitative polymerase chain reaction and western blot were used to determine the expression of mRNA and protein, respectively. Cell Counting Kit-8 (CCK-8) and EdU assay were used to detect the cell proliferation. Double luciferase assay was used to detect the binding relationship between AQP4-AS1 and miR-4464. Results  ALOX15 was the most significantly downregulated FRG compared with normal tissues. Furthermore, protein-protein interaction network analysis indicated that the AQP4-AS1-miR-4476-ALOX15 regulatory axis might be involved in the occurrence and development of LUAD and there might be direct interaction between AQP4-AS1 and miR-4476, and miR-4476 and ALOX15. Furthermore, AQP4-AS1 and ALOX15 were significantly downregulated in the LUAD tissue and cell lines, whereas miR-4476 showed the opposite results ( p  < 0.001). AQP4-AS1 overexpression improved the ALOX15 expression in LUAD cell lines. CCK-8 and EdU assay revealed that overexpression of AQP4-AS1 and ALOX15 inhibited the LUAD cell proliferation. Double luciferase assay results indicated that there was a combination between AQP4-AS1 and miRNA-4476. In addition, we found that overexpressed AQP4-AS1 activates the ferroptosis in LUAD cell lines. Conclusions  AQP4-AS1 can regulate the expression of ALOX15 through competitive binding with miR-4476, further activate ferroptosis and inhibit the proliferation of LUAD cells.

Cold atmospheric plasma enhances SLC7A11-mediated ferroptosis in non-small cell lung cancer by regulating PCAF mediated HOXB9 acetylation

Lung cancer is a leading cause of cancer death worldwide, with high incidence and poor survival rates. Cold atmospheric plasma (CAP) technology has emerged as a promising therapeutic approach for cancer treatment, inducing oxidative stress in malignant tissues without causing thermal damage. However, the role of CAP in regulating lung cancer cell ferroptosis remains unclear. Here, we observed that CAP effectively suppressed the growth and migration abilities of lung cancer cells, with significantly increased ferroptotic cell death, lipid peroxidation, and decreased mitochondrial membrane potential. Mechanistically, CAP regulates SLC7A11-mediated cell ferroptosis by modulating HOXB9. SLC7A11, a potent ferroptosis suppressor, was markedly reduced by HOXB9 knockdown, while it was enhanced by overexpressing HOXB9. The luciferase and ChIP assays confirmed that HOXB9 can directly target SLC7A11 and regulate its gene transcription. Additionally, CAP enhanced the acetylation modification level of HOXB9 by promoting its interaction with acetyltransferase p300/CBP-associated factor (PCAF). Acetylated HOXB9 affects its protein ubiquitination modification level, which in turn affects its protein stability. Notably, the upregulation of SLC7A11 and HOXB9 mitigated the suppressive effects of CAP on ferroptosis status, cell proliferation, invasion, and migration in lung cancer cells. Furthermore, animal models have also confirmed that CAP can inhibit the progression of lung cancer in vivo. Overall, this study highlights the significance of the downregulation of the HOXB9/SLC7A11 axis by CAP treatment in inhibiting lung cancer, offering novel insights into the potential mechanisms and therapeutic strategies of CAP for lung cancer.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

COPZ1 regulates ferroptosis through NCOA4-mediated ferritinophagy in lung adenocarcinoma

BACKGROUND

Ferroptosis, a type of autophagy-dependent cell death, has been implicated in the pathogenesis of lung adenocarcinoma (LUAD). This study aimed to investigate the involvement of coatomer protein complex I subunit zeta 1 (COPZ1) in ferroptosis and ferritinophagy in LUAD.

METHODS

Publicly available human LUAD sample data were obtained from the TCGA database to analyze the association of COPZ1 expression with LUAD grade and patient survival. Clinical samples of LUAD and para-carcinoma tissues were collected. COPZ1-deficient LUAD cell model and xenograft model were established. These models were analyzed to evaluate tumor growth, lipid peroxidation levels, mitochondrial structure, autophagy activation, and iron metabolism.

RESULTS

High expression of COPZ1 was indicative of malignancy and poor overall survival. Clinical LUAD tissues showed increased COPZ1 expression and decreased nuclear receptor coactivator 4 (NCOA4) expression. COPZ1 knockdown inhibited xenograft tumor growth and induced apoptosis. COPZ1 knockdown elevated the levels of ROS, Fe2+ and lipid peroxidation. COPZ1 knockdown also caused mitochondrial shrinkage. Liproxstatin-1, deferoxamine, and z-VAD-FMK reversed the effects of COPZ1 knockdown on LUAD cell proliferation and ferroptosis. Furthermore, COPZ1 was directly bound to NCOA4. COPZ1 knockdown restricted FTH1 expression and promoted NCOA4 and LC3 expression. NCOA4 knockdown reversed the regulation of iron metabolism, lipid peroxidation, and mitochondrial structure induced by COPZ1 knockdown. COPZ1 knockdown induced the translocation of ferritin to lysosomes for degradation, whereas NCOA4 knockdown disrupted this process.

CONCLUSION

This study provides novel evidence that COPZ1 regulates NCOA4-mediated ferritinophagy and ferroptosis. These findings provide new insights into the pathogenesis and potential treatment of LUAD.

In vivo vulnerabilities to GPX4 and HDAC inhibitors in drug-persistent versus drug-resistant BRAFV600E lung adenocarcinoma

The current targeted therapy for BRAFV600E-mutant lung cancer consists of a dual blockade of RAF/MEK kinases often combining dabrafenib/trametinib (D/T). This regimen extends survival when compared to single-agent treatments, but disease progression is unavoidable. By using whole-genome CRISPR screening and RNA sequencing, we characterize the vulnerabilities of both persister and D/T-resistant cellular models. Oxidative stress together with concomitant induction of antioxidant responses is boosted by D/T treatment. However, the nature of the oxidative damage, the choice of redox detoxification systems, and the resulting therapeutic vulnerabilities display stage-specific differences. Persister cells suffer from lipid peroxidation and are sensitive to ferroptosis upon GPX4 inhibition in vivo. Biomarkers of lipid peroxidation are detected in clinical samples following D/T treatment. Acquired alterations leading to mitogen-activated protein kinase (MAPK) reactivation enhance cystine transport to boost GPX4-independent antioxidant responses. Similarly to BRAFV600E-mutant melanoma, histone deacetylase (HDAC) inhibitors decrease D/T-resistant cell viability and extend therapeutic response in vivo.

Regulatory mechanisms of amino acids in ferroptosis

Ferroptosis, an iron-dependent non-apoptotic regulated cell death process, is associated with the pathogenesis of various diseases. Amino acids, which are indispensable substrates of vital activities, significantly regulate ferroptosis. Amino acid metabolism is involved in maintaining iron and lipid homeostasis and redox balance. The regulatory effects of amino acids on ferroptosis are complex. An amino acid may exert contrasting effects on ferroptosis depending on the context. This review systematically and comprehensively summarized the distinct roles of amino acids in regulating ferroptosis and highlighted the emerging opportunities to develop clinical therapeutic strategies targeting amino acid-mediated ferroptosis.

Glutathione dynamics in subcellular compartments and implications for drug development

Glutathione (GSH) is a pivotal tripeptide antioxidant essential for maintaining cellular redox homeostasis and regulating diverse cellular processes. Subcellular compartmentalization of GSH underscores its multifaceted roles across various organelles including the cytosol, mitochondria, endoplasmic reticulum, and nucleus, each exhibiting distinct regulatory mechanisms. Perturbations in GSH dynamics contribute to pathophysiological conditions, emphasizing the clinical significance of understanding its intricate regulation. This review consolidates current knowledge on subcellular GSH dynamics, highlighting its implications in drug development, particularly in covalent drug design and antitumor strategies targeting intracellular GSH levels. Challenges and future directions in deciphering subcellular GSH dynamics are discussed, advocating for innovative methodologies to advance our comprehension and facilitate the development of precise therapeutic interventions based on GSH modulation.

NIR Absorbing Organic Chromophores Combination with NSAIDs for Remodeling of the Inflammatory Microenvironment to Amplify Tumor Ferroptosis-Photothermal Synergistic Therapy

Photothermal therapy has emerged as a promising approach for cancer treatment, which can cause ferroptosis to enhance immunotherapeutic efficacy. However, excessively generated immunogenicity will induce serious inflammatory response syndrome, resulting in a discounted therapeutic effect. Herein, a kind of NIR absorption small organic chromophore nanoparticles (TTHM NPs) with high photothermal conversion efficiency (68.33%) is developed, which can induce mitochondria dysfunction, generate mitochondrial superoxide, and following ferroptosis. TTHM NPs-based photothermal therapy is combined with Sulfasalazine (SUZ), a kind of nonsteroidal anti-inflammatory drugs, to weaken inflammation and promote ferroptosis through suppressing glutamate/cystine (Glu/Cys) antiporter system Xc- (xCT). Additionally, the combination of SUZ with PTT can induce immunogenic cell death (ICD), followed by promoting the maturation of DCs and the attraction of CD8+ T cell, which will secrete IFN-γ and trigger self-amplified ferroptosis via inhibiting xCT and simulating Acyl-CoA synthetase long-chain family member 4 (ACSL4). Moreover, the in vivo results demonstrate that this combination therapy can suppress the expression of inflammatory factors, enhance dendritic cell activation, facilitate T-cell infiltration, and realize effective thermal elimination of primary tumors and distant tumors. In general, this work provides an excellent example of combined medication and stimulates new thinking about onco-therapy and inflammatory response.

Discovery of the Inhibitor Targeting the SLC7A11/xCT Axis through In Silico and In Vitro Experiments

In the development and progression of cervical cancer, oxidative stress plays an important role within the cells. Among them, Solute Carrier Family 7 Member 11 (SLC7A11/xCT) is crucial for maintaining the synthesis of glutathione and the antioxidant system in cervical cancer cells. In various tumor cells, studies have shown that SLC7A11 inhibits ferroptosis, a form of cell death, by mediating cystine uptake and maintaining glutathione synthesis. Additionally, SLC7A11 is also involved in promoting tumor metastasis and immune evasion. Therefore, inhibiting the SLC7A11/xCT axis has become a potential therapeutic strategy for cervical cancer. In this study, through structure-based high-throughput virtual screening, a compound targeting the SLC7A11/xCT axis named compound 1 (PubChem CID: 3492258) was discovered. In vitro experiments using HeLa cervical cancer cells as the experimental cell model showed that compound 1 could reduce intracellular glutathione levels, increase glutamate and reactive oxygen species (ROS) levels, disrupt the oxidative balance within HeLa cells, and induce cell death. Furthermore, molecular dynamics simulation results showed that compound 1 has a stronger binding affinity with SLC7A11 compared to the positive control erastin. Overall, all the results mentioned above indicate the potential of compound 1 in targeting the SLC7A11/xCT axis and treating cervical cancer both in vitro and in silico.

Poor therapeutic outcomes in KRAS-mutant non-small cell lung cancer due to chemoresistance conferred by SLC7A11

PURPOSE

This study aimed to confirm whether Kirsten rat sarcoma viral oncogene (KRAS) mutations affect the therapeutic efficacy of non-small cell lung cancer (NSCLC) and, if so, to explore what the possible mechanisms might be.

METHODS

We retrospectively analyzed the efficacy of immunochemotherapy in KRAS-mutant NSCLC patients compared to driver-negative patients. Online data platforms were used to find immunotherapy cases, and survival analysis compared treatments' efficacy. Cytotoxicity assays measured chemosensitivity in KRAS-mutant versus wild-type NSCLC to drugs like paclitaxel, carboplatin, and pemetrexed. Bioinformatics confirmed the KRAS-SLC7A11 link and cell experiments tested SLC7A11's role in chemoresistance. Animal studies verified the antitumor effects of SLC7A11 inhibitors with chemotherapy.

RESULTS

Patients with KRAS-mutated NSCLC have a shorter therapeutic effectiveness duration with immunochemotherapy than patients with driver gene-negative status. The efficacy of immunotherapy alone is similar between the two groups. The KRAS mutation can enhance chemoresistance by upregulating SLC7A11, and inhibiting SLC7A11 can increase the sensitivity of KRAS-mutated NSCLC to chemotherapy.

CONCLUSION

This study suggests that KRAS-mutant NSCLC can enhance its acquired chemoresistance by overexpressing SLC7A11, leading to poorer therapeutic outcomes. Targeting the KRAS-SLC7A11 axis could increase sensitivity to chemotherapeutic drugs, providing theoretical support for future treatment directions.

SLC7A11: the Achilles heel of tumor?

The non-natriuretic-dependent glutamate/cystine inverse transporter-system Xc- is composed of two protein subunits, SLC7A11 and SLC3A2, with SLC7A11 serving as the primary functional component responsible for cystine uptake and glutathione biosynthesis. SLC7A11 is implicated in tumor development through its regulation of redox homeostasis, amino acid metabolism, modulation of immune function, and induction of programmed cell death, among other processes relevant to tumorigenesis. In this paper, we summarize the structure and biological functions of SLC7A11, and discuss its potential role in tumor therapy, which provides a new direction for precision and personalized treatment of tumors.

Targeting xCT with sulfasalazine suppresses triple-negative breast cancer growth via inducing autophagy and coordinating cell cycle and proliferation

There is a substantial unmet need for effective treatment strategies in triple-negative breast cancer (TNBC). Recently, renewed attention has been directed towards targeting glutamine (Gln) metabolism to enhance the efficacy of cancer treatment. Nonetheless, a comprehensive exploration into the mechanistic implications of targeting Gln metabolism in TNBC is lacking. In this study, our objective was to probe the sensitivity of TNBC to alterations in Gln metabolism, using representative TNBC cell lines: MDA-MB-231, MDA-MB-468, and 4T1. Through an integration of bioinformatics, in-vitro, and in-vivo investigations, we demonstrated that sulfasalazine (SAS), like erastin (a known xCT inhibitor), effectively suppressed the expression and transport function of xCT, resulting in a depletion of glutathione levels in MDA-MB-231 and MDA-MB-468 cells. Furthermore, both xCT knockdown and SAS treatment demonstrated the promotion of cellular autophagy. We unveiled a positive correlation between xCT and the autophagy-related molecule p62, their co-expression indicating poor survival outcomes in breast cancer patients. In addition, our research revealed the influence of SAS and xCT on the expression of proteins regulating cell cycle and proliferation. Treatment with SAS or xCT knockdown led to the inhibition of MYC, CDK1, and CD44 expression. Significantly, the combined administration of SAS and rapamycin exhibited a synergistic inhibitory effect on the growth of transplanted breast tumor in mouse models constructed from murine-derived 4T1 cells. Taken together, our findings suggested the potential and clinical relevance of the SAS and rapamycin combination in the treatment of TNBC.

Fc-Fc interactions and immune inhibitory effects of IgG4: implications for anti-PD-1 immunotherapies

BACKGROUND

The majority of anti-programmed cell-death 1 (PD-1) monoclonal antibodies (mAbs) use S228P mutation IgG4 as the structural basis to avoid the activation of immune cells or complement. However, little attention has been paid to the Fc-Fc interactions between IgG4 and other IgG Fc fragments that could result in adverse effects. Fc-null IgG1 framework is a potential safer alternative to avoid the undesirable Fc-Fc interactions and Fc receptor binding derived effects observed with IgG4. This study provides a comprehensive evaluation of anti-PD-1 mAbs of these two frameworks.

METHODS

Trastuzumab and rituximab (both IgG1), wildtype IgG1 and IgG4 were immobilized on nitrocellulose membranes, coated to microplates and biosensor chips, and bound to tumor cells as targets for Fc-Fc interactions. Wildtype IgG1 and IgG4, anti-PD-1 mAb nivolumab (IgG4 S228P), penpulimab (Fc-null IgG1), and tislelizumab (Fc-null IgG4 S228P-R409K) were assessed for their binding reactions to the immobilized IgG proteins and quantitative kinetic data were obtained. To evaluate the effects of the two anti-PD-1 mAbs on immune responses mediated by trastuzumab and rituximab in the context of combination therapy, we employed classic immune models for antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement dependent cytotoxicity. Tumor-bearing mouse models, both wildtype and humanized, were used for in vivo investigation. Furthermore, we also examined the effects of IgG1 and IgG4 on diverse immune cell populations RESULTS: Experiments demonstrated that wildtype IgG4 and nivolumab bound to immobilized IgG through Fc-Fc interactions, diminishing antibody-dependent cell-mediated cytotoxicity and phagocytosis reactions. Quantitative analysis of kinetic parameters suggests that nivolumab and wildtype IgG4 exhibit comparable binding affinities to immobilized IgG1 in both non-denatured and denatured states. IgG4 exerted inhibitory effects on various immune cell types. Wildtype IgG4 and nivolumab both promoted tumor growth in wildtype mouse models. Conversely, wildtype IgG1, penpulimab, and tislelizumab did not show similar adverse effects.

CONCLUSIONS

Fc-null IgG1 represents a safer choice for anti-PD-1 immunotherapies by avoiding both the adverse Fc-Fc interactions and Fc-related immune inhibitory effects of IgG4. Fc-null IgG4 S228P-R409K and Fc-null IgG1 displayed similar structural properties and benefits. This study contributes to the understanding of immunotherapy resistance and the advancement of safer immune therapies for cancer.

Ferroptosis: principles and significance in health and disease

Ferroptosis, an iron-dependent form of cell death characterized by uncontrolled lipid peroxidation, is governed by molecular networks involving diverse molecules and organelles. Since its recognition as a non-apoptotic cell death pathway in 2012, ferroptosis has emerged as a crucial mechanism in numerous physiological and pathological contexts, leading to significant therapeutic advancements across a wide range of diseases. This review summarizes the fundamental molecular mechanisms and regulatory pathways underlying ferroptosis, including both GPX4-dependent and -independent antioxidant mechanisms. Additionally, we examine the involvement of ferroptosis in various pathological conditions, including cancer, neurodegenerative diseases, sepsis, ischemia-reperfusion injury, autoimmune disorders, and metabolic disorders. Specifically, we explore the role of ferroptosis in response to chemotherapy, radiotherapy, immunotherapy, nanotherapy, and targeted therapy. Furthermore, we discuss pharmacological strategies for modulating ferroptosis and potential biomarkers for monitoring this process. Lastly, we elucidate the interplay between ferroptosis and other forms of regulated cell death. Such insights hold promise for advancing our understanding of ferroptosis in the context of human health and disease.

A guide to ferroptosis in cancer

Ferroptosis is a newly identified iron-dependent type of regulated cell death that can also be regarded as death caused by the specific collapse of the lipid antioxidant defence machinery. Ferroptosis has gained increasing attention as a potential therapeutic strategy for therapy-resistant cancer types. However, many ferroptosis-inducing small molecules do not reach the pharmacokinetic requirements for their effective clinical use yet. Nevertheless, their clinical optimization is under development. In this review, we summarize the current understanding of molecular pathways regulating ferroptosis, how cells protect themselves from the induction of ferroptotic cell death, and how a better understanding of cancer cell metabolism can represent vulnerabilities for ferroptosis-based therapies. Lastly, we discuss the context-dependent effect of ferroptosis on various cell types within the tumor microenvironment and address controversies on how tissue ferroptosis might impact systemic cancer immunity in a paracrine manner.

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.

The new era of lung cancer therapy: Combining immunotherapy with ferroptosis

Ferroptosis is an unconventional programmed cell death mode caused by phospholipid peroxidation dependent on iron. Emerging immunotherapies (especially immune checkpoint inhibitors) have the potential to enhance lung cancer patients' long-term survival. Although immunotherapy has yielded significant positive applications in some patients, there are still many mechanisms that can cause lung cancer cells to evade immunity, thus leading to the failure of targeted therapies. Immune-tolerant cancer cells are insensitive to conventional death pathways such as apoptosis and necrosis, whereas mesenchymal and metastasis-prone cancer cells are particularly vulnerable to ferroptosis, which plays a vital role in mediating immune tolerance resistance by tumors and immune cells. As a result, triggering lung cancer cell ferroptosis holds significant therapeutic potential for drug-resistant malignancies. Here, we summarize the mechanisms underlying the suppression of ferroptosis in lung cancer, highlight its function in the lung cancer immune microenvironment, and propose possible therapeutic strategies.

Apoptosis, a Metabolic "Head-to-Head" between Tumor and T Cells: Implications for Immunotherapy

Induction of apoptosis represents a promising therapeutic approach to drive tumor cells to death. However, this poses challenges due to the intricate nature of cancer biology and the mechanisms employed by cancer cells to survive and escape immune surveillance. Furthermore, molecules released from apoptotic cells and phagocytes in the tumor microenvironment (TME) can facilitate cancer progression and immune evasion. Apoptosis is also a pivotal mechanism in modulating the strength and duration of anti-tumor T-cell responses. Combined strategies including molecular targeting of apoptosis, promoting immunogenic cell death, modulating immunosuppressive cells, and affecting energy pathways can potentially overcome resistance and enhance therapeutic outcomes. Thus, an effective approach for targeting apoptosis within the TME should delicately balance the selective induction of apoptosis in tumor cells, while safeguarding survival, metabolic changes, and functionality of T cells targeting crucial molecular pathways involved in T-cell apoptosis regulation. Enhancing the persistence and effectiveness of T cells may bolster a more resilient and enduring anti-tumor immune response, ultimately advancing therapeutic outcomes in cancer treatment. This review delves into the pivotal topics of this multifaceted issue and suggests drugs and druggable targets for possible combined therapies.

SLC7A11 in hepatocellular carcinoma: potential mechanisms, regulation, and clinical significance

Exploring novel early detection biomarkers and developing more efficacious treatments remain pressing tasks in the current research landscape for hepatocellular carcinoma (HCC). Morphologically and molecularly separate from apoptosis, cell death, and autophagy, ferroptosis is a recently discovered, unique, controlled form of cell death. SLC7A11 (also known as xCT) represents a subunit of the cystine-glutamate antiporter (also known as system Xc(-)). A growing body of research suggests that induction of ferroptosis through SLC7A11 can effectively eliminate hepatocellular carcinoma (HCC) cells, particularly those exhibiting resistance to alternative forms of cell death. Thus, targeting ferroptosis via SLC7A11 may become a new direction for the design of therapeutic strategies for HCC. Although many research articles have investigated the possible roles of SLC7A11 in HCC, a study that summarizes the main findings, including the regulators and mechanisms of action of SLC7A11 in HCC is not available. Therefore, we present a comprehensive overview of the functions of ferroptosis, particularly SLC7A11, in the identification, development, and management of HCC in this review. In addition, we discuss how this knowledge can be translated into treatment by providing a systemic therapy in advanced HCC using sorafenib, the first-line drug targeting multiple kinases and SLC7A11. We further dissect the possible barriers as well as the corresponding solutions and provide insights on how to navigate effective treatment using this knowledge.

Up-regulated ORC1 promotes lung adenocarcinoma by inhibiting ferroptosis via SLC7A11 dependent pathway

Background

Lung adenocarcinoma (LUAD) is a pulmonary malignant disease that poses a high risk of mortality and morbidity. Previous study indicated that ORC1 plays an oncogenic function. However, the precise regulatory function that ORC1 serves in the progression of LUAD is still not clearly known.

Methods

Bioinformatics analyses were performed using TCGA and GEO datasets. The human LUAD cell line NCIH1355, NCIH1568 as well as BEAS-2B cell line (human normal lung epithelial cell) were utilized for in vitro study. LUAD cell proliferation were determined via CCK-8 assays and RT-qPCR for ki-67. The relation of ORC1 and SLC7A11 was detected by Western blot and qPCR with or without sh-RNA. The expression level ACSL4, the biomarker of ferroptosis, were detected using RT-qPCR.

Results

ORC1 and SLC7A11 exhibit high expression levels in both LUAD patients and cell lines, and are strongly associated with poor prognosis. In vitro experiments demonstrate that ORC1 and SLC7A11 promote proliferation of LUAD cell lines while inhibiting gefitinib-induced ferroptosis. Additionally, the function of ORC1 in LUAD cells is dependent on SLC7A11.

Conclusion

ORC1 promotes LUAD cell proliferation and inhibits ferroptosis in a SLC7A11-dependent manner. This implies that ORC1 could potentially serve as a useful diagnosis biomarker and treatment target.

Ferroptotic therapy in cancer: benefits, side effects, and risks

Ferroptosis is a type of regulated cell death characterized by iron accumulation and uncontrolled lipid peroxidation, leading to plasma membrane rupture and intracellular content release. Originally investigated as a targeted therapy for cancer cells carrying oncogenic RAS mutations, ferroptosis induction now exhibits potential to complement chemotherapy, immunotherapy, and radiotherapy in various cancer types. However, it can lead to side effects, including immune cell death, bone marrow impairment, liver and kidney damage, cachexia (severe weight loss and muscle wasting), and secondary tumorigenesis. In this review, we discuss the advantages and offer an overview of the diverse range of documented side effects. Furthermore, we examine the underlying mechanisms and explore potential strategies for side effect mitigation.

Induction of ferroptosis by natural products in non-small cell lung cancer: a comprehensive systematic review

Lung cancer is one of the leading causes of cancer-related deaths worldwide that presents a substantial peril to human health. Non-Small Cell Lung Cancer (NSCLC) is a main subtype of lung cancer with heightened metastasis and invasion ability. The predominant treatment approaches currently comprise surgical interventions, chemotherapy regimens, and radiotherapeutic procedures. However, it poses significant clinical challenges due to its tumor heterogeneity and drug resistance, resulting in diminished patient survival rates. Therefore, the development of novel treatment strategies for NSCLC is necessary. Ferroptosis was characterized by iron-dependent lipid peroxidation and the accumulation of lipid reactive oxygen species (ROS), leading to oxidative damage of cells and eventually cell death. An increasing number of studies have found that exploiting the induction of ferroptosis may be a potential therapeutic approach in NSCLC. Recent investigations have underscored the remarkable potential of natural products in the cancer treatment, owing to their potent activity and high safety profiles. Notably, accumulating evidences have shown that targeting ferroptosis through natural compounds as a novel strategy for combating NSCLC holds considerable promise. Nevertheless, the existing literature on comprehensive reviews elucidating the role of natural products inducing the ferroptosis for NSCLC therapy remains relatively sparse. In order to furnish a valuable reference and support for the identification of natural products inducing ferroptosis in anti-NSCLC therapeutics, this article provided a comprehensive review explaining the mechanisms by which natural products selectively target ferroptosis and modulate the pathogenesis of NSCLC.

Compartmentalized role of xCT in supporting pancreatic tumor growth, inflammation and mood disturbance in mice

xCT (Slc7a11), the specific subunit of the cystine/glutamate antiporter system xc-, is present in the brain and on immune cells, where it is known to modulate behavior and inflammatory responses. In a variety of cancers -including pancreatic ductal adenocarcinoma (PDAC)-, xCT is upregulated by tumor cells to support their growth and spread. Therefore, we studied the impact of xCT deletion in pancreatic tumor cells (Panc02) and/or the host (xCT-/- mice) on tumor burden, inflammation, cachexia and mood disturbances. Deletion of xCT in the tumor strongly reduced tumor growth. Targeting xCT in the host and not the tumor resulted only in a partial reduction of tumor burden, while it did attenuate tumor-related systemic inflammation and prevented an increase in immunosuppressive regulatory T cells. The latter effect could be replicated by specific xCT deletion in immune cells. xCT deletion in the host or the tumor differentially modulated neuroinflammation. When mice were grafted with xCT-deleted tumor cells, hypothalamic inflammation was reduced and, accordingly, food intake improved. Tumor bearing xCT-/- mice showed a trend of reduced hippocampal neuroinflammation with less anxiety- and depressive-like behavior. Taken together, targeting xCT may have beneficial effects on pancreatic cancer-related comorbidities, beyond reducing tumor burden. The search for novel and specific xCT inhibitors is warranted as they may represent a holistic therapy in pancreatic cancer.

Aberrant Expression of SLC7A11 Impairs the Antimicrobial Activities of Macrophages in Staphylococcus Aureus Osteomyelitis in Mice

Staphylococcus aureus (S. aureus) persistence in macrophages, potentially a reservoir for recurrence of chronic osteomyelitis, contributes to resistance and failure in treatment. As the mechanisms underlying survival of S. aureus in macrophages remain largely unknown, there has been no treatment approved. Here, in a mouse model of S. aureus osteomyelitis, we identified significantly up-regulated expression of SLC7A11 in both transcriptomes and translatomes of CD11b+F4/80+ macrophages, and validated a predominant distribution of SLC7A11 in F4/80+ cells around the S. aureus abscess. Importantly, pharmacological inhibition or genetic knockout of SLC7A11 promoted the bactericidal function of macrophages, reduced bacterial burden in the bone and improved bone structure in mice with S. aureus osteomyelitis. Mechanistically, aberrantly expressed SLC7A11 down-regulated the level of intracellular ROS and reduced lipid peroxidation, contributing to the impaired bactericidal function of macrophages. Interestingly, blocking SLC7A11 further activated expression of PD-L1 via the ROS-NF-κB axis, and a combination therapy of targeting both SLC7A11 and PD-L1 significantly enhanced the efficacy of clearing S. aureus in vitro and in vivo. Our findings suggest that targeting both SLC7A11 and PD-L1 is a promising therapeutic approach to reprogram the bactericidal function of macrophages and promote bacterial clearance in S. aureus osteomyelitis.

Pharmacological approaches for targeting lysosomes to induce ferroptotic cell death in cancer

Lysosomes are crucial organelles responsible for the degradation of cytosolic materials and bulky organelles, thereby facilitating nutrient recycling and cell survival. However, lysosome also acts as an executioner of cell death, including ferroptosis, a distinctive form of regulated cell death that hinges on iron-dependent phospholipid peroxidation. The initiation of ferroptosis necessitates three key components: substrates (membrane phospholipids enriched with polyunsaturated fatty acids), triggers (redox-active irons), and compromised defence mechanisms (GPX4-dependent and -independent antioxidant systems). Notably, iron assumes a pivotal role in ferroptotic cell death, particularly in the context of cancer, where iron and oncogenic signaling pathways reciprocally reinforce each other. Given the lysosomes' central role in iron metabolism, various strategies have been devised to harness lysosome-mediated iron metabolism to induce ferroptosis. These include the re-mobilization of iron from intracellular storage sites such as ferritin complex and mitochondria through ferritinophagy and mitophagy, respectively. Additionally, transcriptional regulation of lysosomal and autophagy genes by TFEB enhances lysosomal function. Moreover, the induction of lysosomal iron overload can lead to lysosomal membrane permeabilization and subsequent cell death. Extensive screening and individually studies have explored pharmacological interventions using clinically available drugs and phytochemical agents. Furthermore, a drug delivery system involving ferritin-coated nanoparticles has been specifically tailored to target cancer cells overexpressing TFRC. With the rapid advancements in understandings the mechanistic underpinnings of ferroptosis and iron metabolism, it is increasingly evident that lysosomes represent a promising target for inducing ferroptosis and combating cancer.

The roles of ferroptosis in cancer: Tumor suppression, tumor microenvironment, and therapeutic interventions

In cancer treatment, the recurrent challenge of inducing apoptosis through conventional therapeutic modalities, often thwarted by therapy resistance, emphasizes the critical need to explore alternative cell death pathways. Ferroptosis, an iron-dependent form of regulated cell death triggered by the lethal accumulation of lipid peroxides on cellular membranes, has emerged as one such promising frontier in oncology. Induction of ferroptosis not only suppresses tumor growth but also holds potential for augmenting immunotherapy responses and surmounting resistance to existing cancer therapies. This review navigates the role of ferroptosis in tumor suppression. Furthermore, we delve into the complex role of ferroptosis within the tumor microenvironment and its interplay with antitumor immunity, offering insights into the prospect of targeting ferroptosis as a strategic approach in cancer therapy.

Metabolic plasticity of T cell fate decision

ABSTRACT

The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8 + T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.

Disulfidptosis: disulfide stress-induced cell death

The cystine transporter solute carrier family 7 member 11 (SLC7A11) (also known as xCT) promotes glutathione synthesis and counters oxidative stress-induced cell death, including ferroptosis, by importing cystine. Also, SLC7A11 plays a crucial role in tumor development. However, recent studies have uncovered an unexpected role of SLC7A11 in promoting disulfidptosis, a novel form of regulated cell death induced by disulfide stress. In this review, we examine the opposing roles of SLC7A11 in regulating redox homeostasis and cell survival/death, summarize current knowledge on disulfidptosis, and explore its potential in disease treatment. A deeper understanding of disulfidptosis will offer new insights into fundamental cellular homeostasis and facilitate the development of innovative therapies for disease treatment.

Role of ferroptosis in Porphyromonas gingivalis-induced impairment of epithelial junction

Objectives

This study aims to clarify the effect of ferroptosis by P. gingivalis on periodontal epithelium impairment and potential mechanisms.

Materials and methods

The expression of epithelial junction proteins (CDH1, OCLN, ZO-1), FTL and GPX4 in healthy and periodontitis tissues was analyzed using bioinformatics analysis and validated in vivo. An in vitro model was constructed to evaluate ferroptosis by mitochondria morphology, content of iron and GSH, and level of lipid peroxidation, FTL, GPX4 and SLC7A11. The iron concentration was changed with iron chelator DFO and iron supplementation FAC. The epithelial impairment was assessed by protein expression. To investigate the mechanism, si-MYB (a negative transcription factor of SLC7A11) and GPX4 inhibitor RSL3 were employed.

Results

CDH1, OCLN, ZO-1 and GPX4 expression was decreased, while FTL expression was elevated in periodontitis tissues. Infected cells showed ferroptosis change of the mitochondria with higher level of lipid peroxidation, iron, FTL and lower level of GPX4, GSH, SLC7A11. FAC augmented ferroptosis and weakened epithelial junction, while DFO exhibited a counteractive effect. Silencing MYB rescued SLC7A11, GPX4 and epithelial junction proteins, which was hindered by RSL3.

Conclusions

Our study demonstrated that P. gingivalis weakened the oral epithelial barrier by causing ferroptosis via inhibiting SLC7A11/GSH/GPX4 axis.

Ferroptosis and oxidative stress in endometriosis: A systematic review of the literature

BACKGROUND

Endometriosis (EMT) a common gynecological condition in women, an inflammatory disease characterized by the presence of endometrial tissue on organs and tissues in the pelvis, and is mainly associated with chronic pelvic pain and infertility. As the etiology has not been fully elucidated, current treatment is limited to surgery, hormones and painkillers, with more side effects and difficulty in achieving long-term relief. Oxidative stress manifests itself as an overproduction of reactive oxygen species, which has an integral impact in the pathology of female reproductive disorders. In this review, we evaluate the mechanisms of iron overload-induced oxidative stress and ferroptosis in EMT and their pathophysiological implications.

METHODS

Because the etiology has not been fully elucidated, current treatments are limited to surgery, hormones, and painkillers, which have many side effects and are difficult to achieve long-term relief.

RESULTS

We interpreted that antioxidants as well as ferroptosis inducers show promising results in the treatment of EMT, but their application in this population needs to be further investigated.

CONCLUSION

In combination with the interpretation of previous studies, it was shown that iron overload is present in the peritoneal fluid, endometriotic lesions, peritoneum and macrophages in the abdominal cavity. However, the programmed cellular ferroptosis associated with iron overload is resisted by endometriotic foci, which is critical to the pathophysiology of EMT with local iron overload and inflammation.

Ferroptosis in cancer: From molecular mechanisms to therapeutic strategies

Ferroptosis is a non-apoptotic form of regulated cell death characterized by the lethal accumulation of iron-dependent membrane-localized lipid peroxides. It acts as an innate tumor suppressor mechanism and participates in the biological processes of tumors. Intriguingly, mesenchymal and dedifferentiated cancer cells, which are usually resistant to apoptosis and traditional therapies, are exquisitely vulnerable to ferroptosis, further underscoring its potential as a treatment approach for cancers, especially for refractory cancers. However, the impact of ferroptosis on cancer extends beyond its direct cytotoxic effect on tumor cells. Ferroptosis induction not only inhibits cancer but also promotes cancer development due to its potential negative impact on anticancer immunity. Thus, a comprehensive understanding of the role of ferroptosis in cancer is crucial for the successful translation of ferroptosis therapy from the laboratory to clinical applications. In this review, we provide an overview of the recent advancements in understanding ferroptosis in cancer, covering molecular mechanisms, biological functions, regulatory pathways, and interactions with the tumor microenvironment. We also summarize the potential applications of ferroptosis induction in immunotherapy, radiotherapy, and systemic therapy, as well as ferroptosis inhibition for cancer treatment in various conditions. We finally discuss ferroptosis markers, the current challenges and future directions of ferroptosis in the treatment of cancer.

Ailanthone induces autophagy and ferroptosis in non‑small cell lung cancer Lewis cells

Ailanthone (AIL), a monomer derived from ailanthus in Chinese medicine, has been demonstrated to have antitumor effects, albeit the underlying mechanism is unknown. Autophagy and ferroptosis are two modes of cell death that have been championed as potential mechanisms implicated in the antitumor effects of various drugs. The present study demonstrated that AIL effectively suppresses the Lewis cell proliferation in non-small cell lung cancer using MTT and colony formation assays. Autophagy and ferroptosis were verified using western blotting, immunofluorescence and ferroptosis detection. Additionally, the findings revealed that regulating the AMPK/mTOR/p70S6k signaling pathway may be the underlying mechanism for the antitumor effect of AIL. The present study established a theoretical foundation for further research into the utilization of AIL as a novel antitumor approach.

Ferroptosis-Based Therapeutic Strategies toward Precision Medicine for Cancer

Ferroptosis is a type of iron-dependent programmed cell death characterized by the dysregulation of iron metabolism and the accumulation of lipid peroxides. This nonapoptotic mode of cell death is implicated in various physiological and pathological processes. Recent findings have underscored its potential as an innovative strategy for cancer treatment, particularly against recalcitrant malignancies that are resistant to conventional therapies. This article focuses on ferroptosis-based therapeutic strategies for precision cancer treatment, covering the molecular mechanisms of ferroptosis, four major types of ferroptosis inducers and their inhibitory effects on diverse carcinomas, the detection of ferroptosis by fluorescent probes, and their implementation in image-guided therapy. These state-of-the-art tactics have manifested enhanced selectivity and efficacy against malignant carcinomas. Given that the administration of ferroptosis in cancer therapy is still at a burgeoning stage, some major challenges and future perspectives are discussed for the clinical translation of ferroptosis into precision cancer treatment.

A Nutrient-Deficient Microenvironment Facilitates Ferroptosis Resistance via the FAM60A-PPAR Axis in Pancreatic Ductal Adenocarcinoma

Ferroptosis, a nonapoptotic form of cell death, is an emerging potential therapeutic target for various diseases, including cancer. However, the role of ferroptosis in pancreatic cancer remains poorly understood. Pancreatic ductal adenocarcinoma (PDAC) is characterized by a poor prognosis and chemotherapy resistance, attributed to its high Kirsten rats arcomaviral oncogene homolog mutation rate and severe nutritional deficits resulting from a dense stroma. Several studies have linked rat sarcoma (RAS) mutations to ferroptosis, suggesting that inducing ferroptosis may be an effective strategy against oncogenic RAS-bearing tumors. We investigated the role of Family With Sequence Similarity 60 Member A (FAM60A) in this study, a protein closely associated with a poor prognosis and highly expressed in PDAC and tumor tissue from KrasG12D/+;Trp53R172H/+; Pdx1-Cre mice, in regulating ferroptosis, tumor growth, and gemcitabine sensitivity in vitro and in vivo. Our results demonstrate that FAM60A regulates 3 essential metabolic enzymes, ACSL1/4 and GPX4, to protect PDAC cells from ferroptosis. Furthermore, we found that YY1 transcriptionally regulates FAM60A expression by promoting its transcription, and the Hippo-YY1 pathway is restricted in the low-amino-acid milieu in the context of nutrient deprivation, leading to downstream suppression of peroxisome proliferator-activated receptor and ACSL1/4 and activation of GPX4 pathways. Importantly, FAM60A knockdown sensitized PDAC cells to gemcitabine treatment. A new understanding of FAM60A transcriptional regulation pattern in PDAC and its dual function in ferroptosis reliever and chemotherapy resistance is provided by our study. Targeting FAM60A may therefore offer a promising therapeutic approach for PDAC by simultaneously addressing 2 major features of the disease (high RAS mutation rate and tumor microenvironment nutrient deficiency) and preventing tumor cell metabolic adaptation.

Ferroptosis in cancer immunity and immunotherapy: Multifaceted interplay and clinical implications

Ferroptosis is a type of cell death characterized by iron-dependent phospholipid peroxidation and reactive oxygen species overproduction. Ferroptosis induces immunogenic cell death and elicits anti-tumor immune responses, playing an important role in cancer immunotherapy. Ferroptosis suppression in cancer cells impairs its immunotherapeutic efficacy. To overcome this issue, ferroptosis inducers (FINs) have been combined with other cancer therapies to create an anti-tumor immune microenvironment. However, the ferroptosis-based crosstalk between immune and tumor cells is complex because oxidative products released by ferroptotic tumor cells impair the functions of anti-tumor immune cells, resulting in immunotherapeutic resistance. In the present article, we have reviewed ferroptosis in tumor and immune cells and summarized the crosstalk between ferroptotic tumor cells and the immune microenvironment. Based on the existing literature, we have further discussed future perspectives on opportunities for combining ferroptosis-targeted therapies with cancer immunotherapies.

Exploring Amino Acid Transporters as Therapeutic Targets for Cancer: An Examination of Inhibitor Structures, Selectivity Issues, and Discovery Approaches

Amino acid transporters are abundant amongst the solute carrier family and have an important role in facilitating the transfer of amino acids across cell membranes. Because of their impact on cell nutrient distribution, they also appear to have an important role in the growth and development of cancer. Naturally, this has made amino acid transporters a novel target of interest for the development of new anticancer drugs. Many attempts have been made to develop inhibitors of amino acid transporters to slow down cancer cell growth, and some have even reached clinical trials. The purpose of this review is to help organize the available information on the efforts to discover amino acid transporter inhibitors by focusing on the amino acid transporters ASCT2 (SLC1A5), LAT1 (SLC7A5), xCT (SLC7A11), SNAT1 (SLC38A1), SNAT2 (SLC38A2), and PAT1 (SLC36A1). We discuss the function of the transporters, their implication in cancer, their known inhibitors, issues regarding selective inhibitors, and the efforts and strategies of discovering inhibitors. The goal is to encourage researchers to continue the search and development within the field of cancer treatment research targeting amino acid transporters.

Identification and validation of a disulfidptosis-related genes prognostic signature in lung adenocarcinoma

Disulfidptosis, a newly revealed form of cell death, regulated by numerous genes that has been recently identified. The exact role of disulfidptosis in lung adenocarcinoma (LUAD) still uncertain. Objective of this study was to explore potential prognostic markers among disulfidptosis genes in LUAD. By combining transcriptomic information from Gene Expression Omnibus databases and The Cancer Genome Atlas, we identified differentially expressed and prognostic disulfidptosis genes. By conducting least absolute shrinkage and selection operator with multivariate Cox regression, four disulfidptosis genes were selected to create the prognostic signature. The implementation of the signature separated the training and validation cohorts into groups with high- and low-risk. Subsequently, the model was verified by conducting an independent analysis of receiver operating characteristic (ROC) curves. Further comparisons were made between the two risk-divided groups with regards the tumor microenvironment, immune cell infiltration, immunotherapy response, and drug sensitivity. The signature was constructed using four disulfidptosis-related genes: SLC7A11, SLC3A2, NCKAP1, and GYS1. According to ROC curves, the signature was effective for predicting LUAD prognosis. In addition, the prognostic signature correlated with sensitivity to chemotherapeutic agents and the efficacy of immunotherapy in LUAD. Finally, through external validation, we showed that NCKAP1 are correlated with tumor migration, proliferation, and invasion of LUAD cells. GYS1 affects immune cell, especially M2 macrophage infiltration in the tumor microenvironment. The disulfidptosis four-gene model can reliably predict the prognosis of patients diagnosed with LUAD, thereby providing valuable information for clinical applications and immunotherapy.

Ferroptosis: a dual-edged sword in tumour growth

Ferroptosis, a recently identified form of non-apoptotic cell death, is distinguished by its dependence on iron-triggered lipid peroxidation and accumulation of iron. It has been linked to various disorders, including the development of tumours. Interestingly, ferroptosis appears to exhibit a dual role in the context of tumour growth. This article provides a thorough exploration of the inherent ambivalence within ferroptosis, encompassing both its facilitation and inhibition of tumorous proliferation. It examines potential therapeutic targets associated with ferroptosis, the susceptibility of cancerous cells to ferroptosis, strategies to enhance the efficacy of existing cancer treatments, the interaction between ferroptosis and the immune response to tumours, and the fundamental mechanisms governing ferroptosis-induced tumour progression. A comprehensive understanding of how ferroptosis contributes to tumour biology and the strategic management of its dual nature are crucial for maximizing its therapeutic potential.

Determinants for Antitumor and Protumor Effects of Programmed Cell Death

Cytotoxic anticancer therapies activate programmed cell death in the context of underlying stress and inflammatory signaling to elicit the emission of danger signals, cytokines, and chemokines. In a concerted manner, these immunomodulatory secretomes stimulate antigen presentation and T cell-mediated anticancer immune responses. In some instances, cell death-associated secretomes attract immunosuppressive cells to promote tumor progression. As it stands, cancer cell death-induced changes in the tumor microenvironment that contribute to antitumor or protumor effects remain largely unknown. This is complicated to examine because cell death is often subverted by tumors to circumvent natural, and therapy-induced, immunosurveillance. Here, we provide insights into important but understudied aspects of assessing the contribution of cell death to tumor elimination or cancer progression, including the role of tumor-associated genetics, epigenetics, and oncogenic factors in subverting immunogenic cell death. This perspective will also provide insights on how future studies may address the complex antitumor and protumor immunologic effects of cell death, while accounting for variations in tumor genetics and underlying microenvironment.

Single-cell RNA sequencing reveals the mechanism of PI3K/AKT/mTOR signaling pathway activation in lung adenocarcinoma by KRAS mutation

BACKGROUND

Aberrant activation of the phosphatidlinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway has been shown to play an important role in lung adenocarcinoma (LUAD). The effect of KRAS mutations, one of the important signatures of LUAD, on the PI3K/AKT/mTOR pathway in LUAD remains unclear.

METHODS

The Seurat package and principal component analysis were used for cell categorization of single-cell RNA sequencing data of LUAD. The AUCell score was used to assess the activity of the PI3K/AKT/mTOR pathway. Meanwhile, using the gene expression profiles and mutation profiles in the The Cancer Genome Atlas dataset, LUAD patients were categorized into KRAS-mutant (KRAS-MT) and KRAS-wild-types (KRAS-WT), and the corresponding enrichment scores were calculated using gene set enrichment analysis analysis. Finally, the subpopulation of cells with the highest pathway activity was identified, the copy number variation profile of this subpopulation was inscribed using the inferCNV package and the CMap database was utilized to make predictions for drugs targeting this subpopulation.

RESULTS

There is higher PI3K/AKT/mTOR pathway activity in LUAD epithelial cells with KRAS mutations, and high expression of KRAS, PIK3CA, AKT1 and PDPK1. In particular, we found significantly higher levels of pathway activity and associated gene expression in KRAS-MT than in KRAS-WT. We identified the highest pathway activity on a subpopulation of GRB2+ epithelial cells and the presence of amplified genes within its pathway. Finally, drugs were able to target GRB2+ epithelial cell subpopulations, such as wortmannin, palbociclib and angiogenesis inhibitor.

CONCLUSIONS

The present study provides a basic theory for the activation of the PI3K/AKT/mTOR signaling pathway as a result of KRAS mutations.

A novel iTreg-related signature for prognostic prediction in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer. Most patients are diagnosed at an advanced stage, therefore it is crucial to identify novel prognostic biomarkers for LUAD. As important regulatory cells, inducible regulatory T cells (iTregs) play a vital role in immune suppression and are important for the maintenance of immune homeostasis. This study explored the prognostic value and therapeutic effects of iTreg-related genes in LUAD. Data for LUAD patients, including immune infiltration data, RNA sequencing data, and clinical features, were acquired from The Cancer Genome Atlas, Gene Expression Omnibus, and Tumor Immune Single-cell Hub 2 databases. Immune-related subgroups with different infiltration patterns and iTreg-related genes were identified through univariate and multivariate Cox regression analyses and weighted correlation network analysis. Functional enrichment analyses were performed to explore the underlying mechanisms of iTreg-related genes. A prognostic risk signature was constructed using Cox regression analysis with the least absolute shrinkage and selection operator penalty. The ESTIMATE algorithm was applied to determine the immune status of LUAD patients. We applied the constructed signature to predict chemosensitivity and performed single-cell RNA sequencing analysis. The infiltration of iTregs was identified as an independent factor for predicting patient outcomes. We constructed a prognostic signature based on seven iTreg-related genes (GIMAP5, SLA, MS4A7, ZNF366, POU2AF1, MRPL12, and COL5A1), which was applied to subdivide patients into high- and low-risk subgroups. Our results revealed that patients in the iTreg-related low-risk subgroup had a better prognosis and possibly greater sensitivity to traditional chemotherapy. Our study provides a novel iTreg-related signature to elucidate the mechanisms underlying LUAD prognosis and promote individualized chemotherapy treatment.

Targeting ferroptosis in gastric cancer: Strategies and opportunities

Ferroptosis is a novel form of programmed cell death morphologically, genetically, and biochemically distinct from other cell death pathways and characterized by the accumulation of iron-dependent lipid peroxides and oxidative damage. It is now understood that ferroptosis plays an essential role in various biological processes, especially in the metabolism of iron, lipids, and amino acids. Gastric cancer (GC) is a prevalent malignant tumor worldwide with low early diagnosis rates and high metastasis rates, accounting for its relatively poor prognosis. Although chemotherapy is commonly used to treat GC, drug resistance often leads to poor therapeutic outcomes. In the last several years, extensive research on ferroptosis has highlighted its significant potential in GC therapy, providing a promising strategy to address drug resistance associated with standard cancer therapies. In this review, we offer an extensive summary of the key regulatory factors related to the mechanisms underlying ferroptosis. Various inducers and inhibitors specifically targeting ferroptosis are uncovered. Additionally, we explore the prospective applications and outcomes of these agents in the field of GC therapy, emphasizing their capacity to improve the outcomes of this patient population.

Mechanism of ferroptosis in breast cancer and research progress of natural compounds regulating ferroptosis

Breast cancer is the most prevalent cancer worldwide and its incidence increases with age, posing a significant threat to women's health globally. Due to the clinical heterogeneity of breast cancer, the majority of patients develop drug resistance and metastasis following treatment. Ferroptosis, a form of programmed cell death dependent on iron, is characterized by the accumulation of lipid peroxides, elevated levels of iron ions and lipid peroxidation. The underlying mechanisms and signalling pathways associated with ferroptosis are intricate and interconnected, involving various proteins and enzymes such as the cystine/glutamate antiporter, glutathione peroxidase 4, ferroptosis inhibitor 1 and dihydroorotate dehydrogenase. Consequently, emerging research suggests that ferroptosis may offer a novel target for breast cancer treatment; however, the mechanisms of ferroptosis in breast cancer urgently require resolution. Additionally, certain natural compounds have been reported to induce ferroptosis, thereby interfering with breast cancer. Therefore, this review not only discusses the molecular mechanisms of multiple signalling pathways that mediate ferroptosis in breast cancer (including metastasis, invasion and proliferation) but also elaborates on the mechanisms by which natural compounds induce ferroptosis in breast cancer. Furthermore, this review summarizes potential compound types that may serve as ferroptosis inducers in future tumour cells, providing lead compounds for the development of ferroptosis-inducing agents. Last, this review proposes the potential synergy of combining natural compounds with traditional breast cancer drugs in the treatment of breast cancer, thereby suggesting future directions and offering new insights.

Advances and challenges in the treatment of lung cancer

Lung cancer accounts for a relatively high proportion of malignant tumors. As the most prevalent type of lung cancer, non-small cell lung cancer (NSCLC) is characterized by high morbidity and mortality. Presently, the arsenal of treatment strategies encompasses surgical resection, chemotherapy, targeted therapy and radiotherapy. However, despite these options, the prognosis remains distressingly poor with a low 5-year survival rate. Therefore, it is urgent to pursue a paradigm shift in treatment methodologies. In recent years, the advent of sophisticated biotechnologies and interdisciplinary integration has provided innovative approaches for the treatment of lung cancer. This article reviews the cutting-edge developments in the nano drug delivery system, molecular targeted treatment system, photothermal treatment strategy, and immunotherapy for lung cancer. Overall, by systematically summarizing and critically analyzing the latest progress and current challenges in these treatment strategies of lung cancer, we aim to provide a theoretical basis for the development of novel drugs for lung cancer treatment, and thus improve the therapeutic outcomes for lung cancer patients.

Synergistic anticancer therapy via ferroptosis using modified bovine serum albumin nanoparticles loaded with sorafenib and simvastatin

Ferroptosis is a non-apoptotic cell death pathway characterized by the accumulation of lipid-peroxy radicals within the affected cells. Here, we investigate the synergistic capacity of sorafenib (SOR) and simvastatin (SIM) to trigger ferroptosis for cancer therapy. For precise in-vivo delivery, SOR + SIM was ratiometrically loaded in bovine serum albumin nanoparticles (BSA-NPs) modified with 4-carboxy phenylboronic acid (CPBA). The developed CPBA-BSA(SOR + SIM)-NPs revealed size of 175.2 ± 12.8 nm, with PDI of 0.22 ± 0.03 and Z-potential of -29.6 ± 4.8 mV. Significantly, CPBA-BSA(SOR + SIM)-NPs exhibited > 2 and > 5-fold reduction in IC50 values compared to individual SOR and SIM treatments respectively, in all tested cell lines. Moreover, CPBA-BSA(SOR + SIM)-NPs treated cells exhibited decrease in glutathione levels, increase in malonaldehyde levels and depolarization of mitochondrial membrane potential (JC-1 assay). Pharmacokinetic analysis revealed enhanced AUC0-∞ and MRT levels for SOR and SIM when administered as CPBA-BSA(SOR + SIM)-NPs compared to free drugs. Crucially, in in-vivo experiments, CPBA-BSA(SOR + SIM)-NPs led to a significant reduction in tumor volume compared to various control groups. Histological and biomarker analyses underscore their biocompatibility for clinical applications. In conclusion, this study highlights the potential of CPBA-BSA(SOR + SIM)-NPs as a promising strategy for inducing ferroptosis in cancer cells, concurrently improving drug delivery and therapeutic efficacy. This approach opens new avenues in cancer treatment.

Pancancer analysis reveals the role of disulfidptosis in predicting prognosis, immune infiltration and immunotherapy response in tumors

Disulfidptosis has been reported as a novel cell death process, suggesting a therapeutic strategy for cancer treatment. Herein, we constructed a multiomics data analysis to reveal the effects of disulfidptosis in tumors. Data for 33 kinds of tumors were downloaded from UCSC Xene, and disulfidptosis-related genes (DRGs) were selected from a previous study. After finishing processing data by the R packages, the expression and coexpression of DRGs in different tumors were assessed as well as copy number variations. The interaction network was drawn by STRING, and the activity of disulfidptosis was compared to the single-sample gene set enrichment analysis algorithm. Subsequently, the differences in DRGs for prognosis and clinicopathological features were evaluated, and the tumor immune microenvironment was assessed by the TIMER and TISCH databases. Tumor mutation burden, stem cell features and microsatellite instability were applied to predict drug resistance, and the expression of checkpoints was identified for the prediction of immunotherapy. Moreover, the TCIA, CellMiner and Enrichr databases were also utilized for selecting potential agents. Ten DRGs were differentially expressed in tumors, and the plots of coexpression and interaction revealed their correlation. Survival analysis suggested SLC7A11 as the most prognosis-related DRG with the most significant results. Additionally, the comparison also reflected the differences in DRGs in the status of pathologic lymph node metastasis for 5 types of tumors. The tumor immune microenvironment showed commonality among tumors based on immune infiltration and single-cell sequencing, and the analysis of tumor mutation burden, stemness and microsatellite instability showed a mostly positive correlation with DRGs. Moreover, referring to the prediction about clinical treatment, most DRGs can enhance sensitivity to chemotherapeutic agents but decrease the response to immune inhibitors with increasing expression. In this study, a primarily synthetic landscape of disulfidptosis in tumors was established and provided guidance for further exploration and investigation.

Oncogenic KRAS effector USP13 promotes metastasis in non-small cell lung cancer through deubiquitinating β-catenin

KRAS mutations are frequently detected in non-small cell lung cancers (NSCLCs). Although covalent KRASG12C inhibitors have been developed to treat KRASG12C-mutant cancers, effective treatments are still lacking for other KRAS-mutant NSCLCs. Thus, identifying a KRAS effector that confers poor prognosis would provide an alternative strategy for the treatment of KRAS-driven cancers. Here, we show that KRAS drives expression of deubiquitinase USP13 through Ras-responsive element-binding protein 1 (RREB1). Elevated USP13 promotes KRAS-mutant NSCLC metastasis, which is associated with poor prognosis in NSCLC patients. Mechanistically, USP13 interacts with and removes the K63-linked polyubiquitination of β-catenin at lysine 508, which enhances the binding between β-catenin and transcription factor TCF4. Importantly, we identify 2-methoxyestradiol as an effective inhibitor for USP13 from a natural compound library, and it could potently suppress the metastasis of KRAS-mutant NSCLC cells in vitro and in vivo. These findings identify USP13 as a therapeutic target for metastatic NSCLC with KRAS mutations.

Expression of Ferroptosis-Related Proteins Glutathione Peroxidase 4, Nuclear Factor Erythroid 2-Related Factor 2, and Solute Carrier Family 7 Member 11 in Gastric Cancer Patients

BACKGROUND/AIMS

The aim of this study was to investigate the expression of ferroptosis-related targets glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 in gastric cancer and the correlation between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients.

MATERIALS AND METHODS

Forty-two gastric cancer samples and paracancerous samples were included, and all cases were detected with glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 by immunohistochemistry. Six gastric cancer cell lines and 1 normal gastric epithelial cell were stably cultured, and the expression of target genes of different cell lines was detected using western blot and polymerase chain reaction. Public data were downloaded from the database, and analyses were performed by software including Statistical Package for the Social Sciences and Prism.

RESULTS

A high glutathione peroxidase 4 expression level was found in 7 (16.67%) cancer tissues and 0 (0.00%) paracancerous tissues (P = .012). Nuclear factor erythroid 2-related factor 2 was upregulated in 23 (54.76%) cancer tissues and 2 (4.76%) paracancerous tissues (P < .001). Solute carrier family 7 member 11 showed increased expression in 4 (9.52%) cancer tissues and 1 (2.38%) paracancerous tissue (P = .356). No significant association existed between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients. Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were higher in all 6 gastric cancer cell lines compared to normal gastric epithelial cells.

CONCLUSION

Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were significantly higher in gastric cancer, which may be potential biomarkers of gastric cancer.

Neurotransmitter Receptor HTR2B Regulates Lipid Metabolism to Inhibit Ferroptosis in Gastric Cancer

Nerves can support tumor development by secreting neurotransmitters that promote cancer cell proliferation and invasion. 5-Hydroxytryptamine (5-HT) is a critical neurotransmitter in the gastrointestinal nervous system, and 5-HT signaling has been shown to play a role in tumorigenesis. Here, we found that expression of the 5-HT receptor HTR2B was significantly elevated in human gastric adenocarcinoma tissues compared with nontumor tissues, and high HTR2B expression corresponded to shorter patient survival. Both 5-HT and a specific HTR2B agonist enhanced gastric adenocarcinoma cell viability under metabolic stress, reduced cellular and lipid reactive oxygen species, and suppressed ferroptosis; conversely, HTR2B loss or inhibition with a selective HTR2B antagonist yielded the inverse tumor suppressive effects. In a patient-derived xenograft tumor model, HTR2B-positive tumors displayed accelerated growth, which was inhibited by HTR2B antagonists. Single-cell analysis of human gastric adenocarcinoma tissues revealed enrichment of PI3K/Akt/mTOR and fatty acid metabolism-related gene clusters in cells expressing HTR2B compared with HTR2B-negative cells. Mechanistically, HTR2B cooperated with Fyn to directly regulate p85 activity and trigger the PI3K/Akt/mTOR signaling pathway, which led to increased expression of HIF1α and ABCD1 along with decreased levels of lipid peroxidation and ferroptosis. Together, these findings demonstrate that HTR2B activity modulates PI3K/Akt/mTOR signaling to stimulate gastric cancer cell survival and indicate that HTR2B expression could be a potential prognostic biomarker in patients with gastric cancer.

SIGNIFICANCE

Nerve cancer cross-talk mediated by HTR2B inhibits lipid peroxidation and ferroptosis in gastric cancer cells and promotes viability under metabolic stress, resulting in increased tumor growth and decreased patient survival.