SLC38A5 promotes glutamine metabolism and inhibits cisplatin chemosensitivity in breast cancer

Identification of the shared gene signatures in retinoblastoma and osteosarcoma by machine learning

Osteosarcoma (OS) is the most prevalent secondary sarcoma associated with retinoblastoma (RB). However, the molecular mechanisms driving the interactions between these two diseases remain incompletely understood. This study aims to explore the transcriptomic commonalities and molecular pathways shared by RB and OS, and to identify biomarkers that predict OS prognosis effectively. RNA sequences and patient information for OS and RB were obtained from the University of California Santa Cruz (UCSC) Xena and Gene Expression Omnibus databases. When RB and OS were first identified, a common gene expression profile was discovered. Weighted Gene Co-expression Network Analysis (WGCNA) revealed co-expression networks associated with OS after immunotyping patients. To evaluate the genes shared by RB and OS, univariate and multivariate Cox regression analysis were then carried out. Three machine learning methods were used to pick key genes, and risk models were created and verified. Next, medications that target independent prognostic genes were found using the Cellminer database. The comparison of differential gene expression between OS and RB revealed 1216 genes, primarily linked to the activation and proliferation of immune cells. WGCNA identified 12 modules related to OS immunotyping, with the grey module showing a strong correlation with the immune-inflamed phenotype. This module intersected with differential genes from RB, producing 65 RB-associated OS Immune-inflamed Genes (ROIGs). Analysis identified 6 hub genes for model construction through univariate Cox regression and three machine learning techniques. A risk model based on these hub genes was established, demonstrating significant prognostic value for OS. Genes shared between OS and RB contribute to the progression of both cancers through multiple pathways. The ROIGs risk score model independently predicts the overall survival of OS patients. Additionally, this study highlights genes with potential as therapeutic targets or biomarkers for clinical use.

SLC38A5 suppresses ferroptosis through glutamine-mediated activation of the PI3K/AKT/mTOR signaling in osteosarcoma

BACKGROUND

Solute carrier family 38 member 5 (SLC38A5) is an amino acid transporter that plays a significant role in various cellular biological processes and may be involved in regulating the progression of tumors However, its function and underlying mechanism in osteosarcoma remain unexplored.

METHODS

Utilizing various database analyses and experiments, we have explored the dysregulation of SLC38A5 in osteosarcoma and its prognostic value. A series of in vitro functional experiments, including CCK-8, colony formation, wound healing, and transwell invasion assays, were conducted to evaluate the effects of SLC38A5 on the proliferation, migration, and invasion of osteosarcoma cells. Downstream pathways of SLC38A5 were explored through methods such as western blot and metabolic assays, followed by a series of validations. Finally, we constructed a subcutaneous xenograft tumor model in nude mice to explore SLC38A5 function in vivo.

RESULTS

SLC38A5 is upregulated in osteosarcoma and is associated with poor prognosis in patients. Upregulation of SLC38A5 promotes proliferation, migration, and invasion of osteosarcoma cells, while the PI3K inhibitor BKM120 can counteract these effects. Additionally, silencing of SLC38A5 inhibits tumor growth in vivo. Mechanistically, SLC38A5 mediates the activation of the PI3K/AKT/mTOR signaling pathway by transporting glutamine, which subsequently enhances the SREBP1/SCD-1 signaling pathway, thereby suppressing ferroptosis in osteosarcoma cells.

CONCLUSION

SLC38A5 promotes osteosarcoma cell proliferation, migration, and invasion via the glutamine-mediated PI3K/AKT/mTOR signaling pathway and inhibits ferroptosis. Targeting SLC38A5 and the PI3K/AKT signaling axis may provide a meaningful therapeutic strategy for the future treatment of osteosarcoma.

Impact of Oncogenic Changes in p53 and KRAS on Macropinocytosis and Ferroptosis in Colon Cancer Cells and Anticancer Efficacy of Niclosamide with Differential Effects on These Two Processes

Mutations in p53 and KRAS are seen in most cases of colon cancer. The impact of these mutations on signaling pathways related to cancer growth has been studied in depth, but relatively less is known on their effects on amino acid transporters in cancer cells. This represents a significant knowledge gap because amino acid nutrition in cancer cells profoundly influences macropinocytosis and ferroptosis, two processes with opposing effects on tumor growth. Here, we used isogenic colon cancer cell lines to investigate the effects of p53 deletion and KRAS activation on two amino acid transporters relevant to macropinocytosis (SLC38A5) and ferroptosis (SLC7A11). Our studies show that the predominant effect of p53 deletion is to induce SLC7A11 with the resultant potentiation of antioxidant machinery and protection of cancer cells from ferroptosis, whereas KRAS activation induces not only SLC7A11 but also SLC38A5, thus offering protection from ferroptosis as well as improving amino acid nutrition in cancer cells via accelerated macropinocytosis. Niclosamide, an FDA-approved anti-helminthic, blocks the functions of SLC7A11 and SLC38A5, thus inducing ferroptosis and suppressing macropinocytosis, with the resultant effective reversal of tumor-promoting actions of oncogenic changes in p53 and KRAS. These findings underscore the potential of this drug in colon cancer treatment.

Oxidative Stress in Breast Cancer: A Biochemical Map of Reactive Oxygen Species Production

This review systematizes information about the metabolic features of breast cancer directly related to oxidative stress. It has been shown those redox changes occur at all levels and affect many regulatory systems in the human body. The features of the biochemical processes occurring in breast cancer are described, ranging from nonspecific, at first glance, and strictly biochemical to hormone-induced reactions, genetic and epigenetic regulation, which allows for a broader and deeper understanding of the principles of oncogenesis, as well as maintaining the viability of cancer cells in the mammary gland. Specific pathways of the activation of oxidative stress have been studied as a response to the overproduction of stress hormones and estrogens, and specific ways to reduce its negative impact have been described. The diversity of participants that trigger redox reactions from different sides is considered more fully: glycolytic activity in breast cancer, and the nature of consumption of amino acids and metals. The role of metals in oxidative stress is discussed in detail. They can act as both co-factors and direct participants in oxidative stress, since they are either a trigger mechanism for lipid peroxidation or capable of activating signaling pathways that affect tumorigenesis. Special attention has been paid to the genetic and epigenetic regulation of breast tumors. A complex cascade of mechanisms of epigenetic regulation is explained, which made it possible to reconsider the existing opinion about the triggers and pathways for launching the oncological process, the survival of cancer cells and their ability to localize.

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.