Targeting SNRNP200-Induced Splicing Dysregulation: A New Strategy for Immunotherapy in Glycolytic Triple-Negative Breast Cancer

Background

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, characterized by extremely high recurrence and mortality rates. Despite significant recent advances in research on TNBC subtypes, including subclassification based on metabolic pathways (e.g., lipid metabolism, glycolysis, and mixed subtypes), therapeutic strategies targeting tumor metabolism still face enormous challenges in practical applications. Existing drugs such as lactate dehydrogenase (LDH) inhibitors, although effective in glycolytic TNBC, are limited in overall efficacy due to side effects on non-tumor cells, such as stromal and immune cells.

RNA splicing is an important mechanism regulating gene expression, and its role in tumor metabolism is gradually being revealed. Some studies have shown that aberrations in spliceosome components are a major cause of splicing dysregulation in cancer, and the regulation of specific splicing genes can selectively induce tumor cell death without affecting normal breast epithelial cells. Therefore, targeting RNA splicing holds potential as a breakthrough in TNBC treatment.

Summary of the Study

This study, conducted by Wenxiao Yang and colleagues at the Fudan University Shanghai Cancer Center, was published in Cell Discovery. By analyzing multi-omics data from 465 TNBC patients (including transcriptomics, proteomics, and metabolomics), the study revealed widespread RNA splicing dysregulation and increased spliceosome abundance in glycolytic TNBC. Furthermore, it identified SNRNP200 as a key mediator of glucose-driven metabolic reprogramming.

The study demonstrated that SNRNP200 regulates the production of lactate and glutathione by splicing key metabolic enzymes (such as GAPDH, ALDOA, and GSS), leading to immune evasion of the tumor. By designing antisense oligonucleotide (ASO) therapy targeting SNRNP200, the researchers were able to not only inhibit tumor metabolism but also significantly enhance the efficacy of anti-PD-1 immunotherapy.

Research Process and Methods

Data Integration and Spliceosome Analysis

The research team integrated transcriptomic, proteomic, and metabolomic data and found that RNA-related proteins (especially RNA splicing-related proteins) were significantly upregulated in TNBC. Principal component analysis (PCA) and t-SNE dimensionality reduction analysis further confirmed that the glycolytic subtype of TNBC (MPS2) displayed unique RNA splicing characteristics. These characteristics include significantly elevated expression of core spliceosome genes, particularly SNRNP200 in the U5 snRNP complex.

Functional Verification of SNRNP200

Through weighted gene coexpression network analysis (WGCNA), the researchers found that SNRNP200 is significantly correlated with glycolytic metabolism. Under high-glucose conditions, the protein levels of SNRNP200 significantly increased, and acetylation at lysine 1610 protected it from proteasomal degradation. Splicing regulation experiments showed that SNRNP200 enhances RNA splicing of metabolic enzyme-coding genes with weak 5’ splice sites, promoting lactate and glutathione production.

In both in vitro and in vivo experiments, SNRNP200 knockdown significantly inhibited the proliferation of glycolytic TNBC cells and induced apoptosis. Using ASO targeting SNRNP200 effectively reduced its expression level and significantly inhibited tumor growth.

Relationship Between SNRNP200 and the Immune Microenvironment

Lactate and glutathione play important roles in regulating the immune microenvironment. High lactate levels promote PD-1 expression in regulatory T cells (Tregs), while glutathione maintains Treg functionality, weakening the effect of anti-PD-1 therapy. The study found that ASO-SNRNP200 treatment reduced lactate and glutathione levels in tumors, significantly enhanced the activity of CD8+ T cells, and inhibited the immunosuppressive function of Tregs.

After combining ASO-SNRNP200 with anti-PD-1 antibody treatment, tumor growth was significantly suppressed in mouse models, while interferon-γ and granzyme B production increased in CD8+ T cells, and FOXP3 and PD-1 expression decreased in Tregs. These results further validated the synergistic effect of ASO-SNRNP200 and immunotherapy.

Clinical Significance and Future Prospects

The study demonstrated that high expression of SNRNP200 in glycolytic TNBC could serve as a negative predictor of immunotherapy response. Furthermore, the combination of ASO-SNRNP200 with anti-PD-1 treatment shows great potential in enhancing the therapeutic efficacy of glycolytic TNBC. Compared with traditional metabolic inhibitors, ASO-SNRNP200 has higher selectivity and safety, with minimal impact on normal cells.

Future research should focus on the following directions: 1. Clinical Validation: Validate the clinical predictive value of SNRNP200 and the efficacy of ASO therapy in large patient cohorts. 2. Mechanistic Deepening: Explore the interactions between other spliceosome components and metabolic pathways to further elucidate the complex network of RNA splicing in cancer metabolic reprogramming. 3. Personalized Treatment: Develop precise treatment strategies for different TNBC subtypes based on patients’ metabolic and splicing characteristics.

Summary

This study reveals the complex relationship between RNA splicing and metabolic reprogramming, identifying SNRNP200 as a key driver of metabolic dysregulation and immune evasion in glycolytic TNBC. It proposes an innovative treatment approach combining ASO-SNR.