Mesothelioma cell heterogeneity identified by single cell RNA sequencing

Our plain-English summary of Mesothelioma cell heterogeneity identified by single cell RNA sequencing, by L. Wu, Z. Wang, A. Zia, et al (Scientific Reports, 2025).

The study

• Authors: L. Wu, Z. Wang, A. Zia, S.O. Kelley, M. de Perrot
• Journal: Scientific Reports
• Published: 2025;15(1):8725
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Mesothelioma cell heterogeneity encompasses diverse morphological and molecular characteristics observed within tumors, significantly impacting disease progression, treatment outcomes, and the development of targeted therapies. This heterogeneity has long posed challenges for accurate diagnosis and effective treatment, but understanding its complexities offers the potential for novel diagnostic modalities and therapeutic interventions. This study employed single-cell RNA sequencing (scRNA-seq) to investigate mesothelioma cell heterogeneity from various sources, including cell culture (CC), peritoneal lavage (Lav) from the tumor microenvironment, and circulating tumor cells (CTC) in murine models. Gene set enrichment analysis was used to identify distinct gene signatures for each subpopulation. The results revealed unique characteristics for mesothelioma cells depending on their origin. In the CC group, up-regulated genes were primarily involved in tumor cell cycle control, proliferation, and apoptosis. In the CTC group, up-regulated genes were associated with cancer cell stemness. The Lav group showed up-regulated genes facilitating interactions between tumor cells and the microenvironment, such as epithelial-mesenchymal transition and immune responses mediated by IFN-α and IFN-γ. Some pathways were shared among all tumor cells, suggesting the potential for transitioning between functional states under specific conditions. This may be the first study to explore circulating mesothelioma cell heterogeneity using scRNA-seq. The distinct gene signatures identified in each mesothelioma cell subpopulation likely play critical roles in tumor initiation and progression, offering potential novel targets for therapeutic intervention. These findings could help inform the development of more effective, personalized treatments for mesothelioma, ultimately improving patient outcomes.

© 2025. The Author(s).

In plain English

This was a laboratory study in mice. The authors used RN5, a mouse mesothelioma cell line their team had earlier derived from mice after asbestos exposure. The article does not name the fiber type. They used single-cell RNA sequencing to compare gene activity in three groups of RN5 cells: cells grown in culture, tumor cells washed from the abdominal cavity (peritoneal lavage), and tumor cells in the blood. The last two groups came from mice 4 weeks after the cells were injected into the abdomen. Of 32,371 cells analyzed, 8208 were identified as tumor cells. Cultured cells showed gene activity linked to cell division and growth. Circulating cells showed overlap with stem cell gene sets. Lavage cells overlapped most with epithelial–mesenchymal transition genes: 14 of their 105 up-regulated genes (13.33%) matched a human gene set, and 13 (12.38%) matched a mouse set. In a human mesothelioma database (TCGA), higher expression of the cultured-cell gene set was associated with poorer survival (logrank p = 0.00018). The circulating and lavage gene sets were not significantly associated with survival (p = 0.68 and 0.11). The authors concluded their findings may offer clues to new treatment targets.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal and laboratory experiment using single-cell RNA sequencing of a mouse mesothelioma cell line grown in culture and in mice, with additional analysis of human mesothelioma data from The Cancer Genome Atlas (TCGA)
• Who was studied: Murine mesothelioma RN5 cells in three groups: cultured cells (CC), peritoneal lavage tumor cells (Lav) and circulating tumor cells (CTC). The Lav and CTC cells came from 6–8 week-old C57BL/6 mice injected intraperitoneally with RN5 cells. Blood was pooled from 20 tumor-bearing mice at 4 weeks. The work was done at the University Health Network, Toronto. Human survival data came from the TCGA mesothelioma (MESO) cohort.
• Exposure: Not an asbestos exposure study. The RN5 cell line had previously been derived from mice after asbestos exposure; this article does not state the fiber type. In this study, mice were injected intraperitoneally with 2 × 10^6 RN5 cells.
• Main results:
  • Of 32,371 cells analyzed across all groups, 8208 were identified as tumor cells by expression of Msln, Wt1 and Sparc
  • Tumor cells were reclustered into subpopulations: 6 clusters for cultured cells, 4 for circulating tumor cells and 5 for lavage cells
  • Up-regulated genes meeting the study criteria numbered 258 in cultured cells, 147 in circulating tumor cells and 105 in lavage cells
  • In cultured cells, the enriched pathways were those linked to cell cycle and proliferation: MYC targets, E2F targets, mTORC1 signaling, unfolded protein response and G2M checkpoint
  • In circulating tumor cells, cluster 3 showed higher overlap with several stem cell gene sets than the other clusters
  • Each group's up-regulated genes were compared with the human EMT gene set. The overlap was 5 genes (1.98%) in cultured cells, 9 genes (6.12%) in circulating tumor cells and 14 genes (13.33%) in lavage cells.
  • Each group's up-regulated genes were also compared with the mouse EMT gene set. The overlap was 5 genes (1.98%) in cultured cells, 9 genes (6.12%) in circulating tumor cells and 13 genes (12.38%) in lavage cells.
  • In lavage cells, EMT was accompanied by an IFN-α and IFN-γ response
  • In TCGA mesothelioma patients, higher expression of the cultured-cell gene signature was associated with poorer prognosis (logrank p = 0.00018)
  • The circulating tumor cell and lavage gene signatures did not show a significant association with patient survival (logrank p = 0.68 and 0.11, respectively)
  • In TCGA data, the overall immune cell infiltration score was higher for the cultured-cell genes than for the circulating and lavage groups
• The authors' conclusion: The authors concluded that their findings may provide clues to the functions contributing to tumor development and progression, and may help in the search for potential new therapeutic targets

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Disease Progression, Tumor Microenvironment, Apoptosis.

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