Arginine Deprivation in SCLC: Mechanisms and Perspectives for Therapy

Cross-omics strategies and personalised options for lung cancer immunotherapy

Lung cancer is one of the most common malignant tumours worldwide and its high mortality rate makes it a leading cause of cancer-related deaths. To address this daunting challenge, we need a comprehensive understanding of the pathogenesis and progression of lung cancer in order to adopt more effective therapeutic strategies. In this regard, integrating multi-omics data of the lung provides a highly promising avenue. Multi-omics approaches such as genomics, transcriptomics, proteomics, and metabolomics have become key tools in the study of lung cancer. The application of these methods not only helps to resolve the immunotherapeutic mechanisms of lung cancer, but also provides a theoretical basis for the development of personalised treatment plans. By integrating multi-omics, we have gained a more comprehensive understanding of the process of lung cancer development and progression, and discovered potential immunotherapy targets. This review summarises the studies on multi-omics and immunology in lung cancer, and explores the application of these studies in early diagnosis, treatment selection and prognostic assessment of lung cancer, with the aim of providing more personalised and effective treatment options for lung cancer patients.

Multi-omics landscape analysis reveals the pan-cancer association of arginine biosynthesis genes with tumor immune evasion and therapy resistance

Background

The metabolism of arginine, a conditionally essential amino acid, plays a crucial role in cancer progression and prognosis. However, a more detailed understanding of the influence of arginine biosynthesis genes in cancer is currently unavailable.

Methods

We performed an integrative multi-omics analysis using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to determine the characteristics of these genes across multiple cancer types. To measure the overall activity of arginine biosynthesis genes in cancer, we calculated arginine biosynthesis scores based on gene expression.

Results

Our results indicated that the arginine biosynthesis score was negatively correlated with immune-related pathways, immune infiltration, immune checkpoint expression, and patient prognosis, and single-cell data further clarified that patients with high arginine biosynthesis scores showed a reduced proportion of T and B cells in an immune desert tumor microenvironment and were insensitive to immunotherapy. We also identified several potential drugs through the Cancer Therapeutic Response Portal (CTRP) and Genomics of Drug Sensitivity in Cancer (GDSC) databases that could target arginine biosynthesis genes and potentially improve the response rate to immunotherapy in patients with a high arginine biosynthesis fraction.

Conclusion

Overall, our analyses emphasize that arginine biosynthesis genes are associated with immune evasion in several cancers. Targeting these genes may facilitate more effective immunotherapy.

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms and strategies

Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.

Extracellular arginine is required but the arginine transporter CAT3 (Slc7a3) is dispensable for mouse normal and malignant hematopoiesis

Amino acid-mediated metabolism is one of the key catabolic and anabolic processes involved in diverse cellular functions. However, the role of the semi-essential amino acid arginine in normal and malignant hematopoietic cell development is poorly understood. Here we report that a continuous supply of exogenous arginine is required for the maintenance/function of normal hematopoietic stem cells (HSCs). Surprisingly, knockout of Slc7a3 (CAT3), a major L-arginine transporter, does not affect HSCs in steady-state or under stress. Although Slc7a3 is highly expressed in naïve and activated CD8 T cells, neither T cell development nor activation/proliferation is impacted by Slc7a3 depletion. Furthermore, the Slc7a3 deletion does not attenuate leukemia development driven by Pten loss or the oncogenic Ptpn11^E76K mutation. Arginine uptake assays reveal that L-arginine uptake is not disrupted in Slc7a3 knockout cells. These data suggest that extracellular arginine is critically important for HSCs, but CAT3 is dispensable for normal hematopoiesis and leukemogenesis.