Proliferation of pleural mesothelioma cells is enhanced by the microRNA-197-3p activity

Our plain-English summary of Proliferation of pleural mesothelioma cells is enhanced by the microRNA-197-3p activity, by I. Bononi, G. Di Mauro, M.L. Tramarin, et al (Frontiers in Oncology, 2026).

The study

• Authors: I. Bononi, G. Di Mauro, M.L. Tramarin, V. Esposito, G. Tonnini, L. Oton-Gonzalez, B. Dallan, E. Torreggiani, F. Martini, M. Tognon
• Journal: Frontiers in Oncology
• Published: 2026;16:1807528
• Read it: PubMed · Publisher · Free full text

Abstract

Human Pleural Mesothelioma (HPM) is an aggressive asbestos-related tumor with limited treatment options and a poor prognosis. MicroRNAs (miRNAs), known to play key roles in the pathogenesis of HPM, have emerged as promising candidates for both diagnostic and therapeutic applications. Among them, miR-197-3p has been previously identified as dysregulated in sera from HPM patients and workers ex-exposed to asbestos fibers. To investigate the functional role of miR-197-3p, loss- and gain-of-function studies were performed in HPM cell lines and human mesothelial cells (HMC) using miR-197-3p-specific antagomiR and mimic. The effects of miR-197-3p modulation on cell proliferation, viability, migration, and apoptosis were evaluated. In addition, bioinformatics analyses were performed to identify potential miR-197-3p target genes, which were subsequently evaluated at both mRNA and protein levels. MiR-197-3p tested significantly upregulated in HPM cells. Its inhibition led to a marked reduction of the HPM cell proliferation, whereas its overexpression in HMC promoted a proliferative phenotype, supporting a potential role in cell growth regulation. Among the predicted targets, TGF-β1 and p120 showed modulation at the mRNA level, although protein-level changes were limited or only partially consistent. These findings suggest that miR-197-3p may contribute to HPM pathogenesis by promoting cell proliferation and influencing critical molecular pathways. However, the underlying molecular mechanisms remain to be fully elucidated, and the interaction with candidate targets, such as TGF-β1 and p120, should be considered putative. Further investigations, including functional and mechanistic validation in more representative experimental models, will be required to clarify the role of miR-197-3p in HPM pathobiology.

Copyright © 2026 Bononi, Di Mauro, Tramarin, Esposito, Tonnini, Oton-Gonzalez, Dallan, Torreggiani, Martini and Tognon.

In plain English

This brief research report described a laboratory study of cells grown in dishes. No people or animals were studied, and no cells were exposed to asbestos. The authors examined a molecule, microRNA-197-3p, in three human pleural mesothelioma cell lines (one each of the epithelioid, biphasic and sarcomatoid types) and in normal human mesothelial cells for comparison. Levels of miR-197-3p were significantly higher in all three mesothelioma lines than in the normal cells. Blocking the molecule reduced colony formation by about 96% in epithelioid, 64% in biphasic and 97% in sarcomatoid cells compared with controls. Adding extra miR-197-3p to normal cells did not significantly increase colony formation. The main text reported no significant changes in viability, migration or apoptosis (a form of cell death), but a supplementary figure reported significant viability drops in blocked epithelioid cells at 24 and 48 hours and biphasic cells at 72 hours. Two genes, TGF-beta1 and p120, changed at the RNA level, but protein changes were limited. The authors concluded that miR-197-3p may be associated with enhanced growth capacity. They called the mechanistic evidence preliminary.

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: Laboratory (in vitro) cell-culture study published as a brief research report. It used loss-of-function (antagomiR inhibitor) and gain-of-function (mimic) experiments plus bioinformatic target prediction.
• Who was studied: Three established human pleural mesothelioma (HPM) cell lines from the authors' repository: epithelioid MPP89, biphasic MSTO-211H and sarcomatoid PPM-Mill. Commercially purchased normal human mesothelial cells (HMC) served as controls. Experiments used three independent biological replicates. No human participants were involved.
• Exposure: No asbestos exposure was tested in this study. The experimental intervention changed miR-197-3p levels: an inhibitor (antagomiR) was given to the three HPM cell lines and a mimic to the normal mesothelial cells. RNA effects were measured 72 hours later, and colony formation at day 10.
• Main results:
  • miR-197-3p was significantly higher in HPM cells than in HMC. Epithelioid vs HMC: p less than 0.0001. Biphasic vs HMC: p=0.0017. Sarcomatoid vs HMC: p=0.0228. Epithelioid cells also had higher levels than sarcomatoid cells (p=0.0012).
  • In HPM cells, the antagomiR significantly reduced colony formation compared with untransfected controls. The reduction was about 96% in epithelioid cells (p=0.0240), 64% in biphasic cells (p=0.0098) and 97% in sarcomatoid cells (p=0.0181).
  • In normal mesothelial cells (HMC), the miR-197-3p mimic did not produce a statistically significant increase in colony formation.
  • The main text states that raising or lowering miR-197-3p did not significantly change cell viability, migration or apoptosis in HPM or HMC cells compared with their controls.
  • The legend of Supplementary Figure 1 reports a statistically significant decrease in viability in epithelioid HPM cells at 24 and 48 hours after antagomiR transfection. This conflicts with the main text.
  • The same supplementary legend reports a significant decrease in viability in biphasic HPM cells at 72 hours after transfection.
  • In HPM cells given the inhibitor, p120 mRNA rose about 1.6-fold. This was significant vs untreated control (p=0.0280) and vs mock (p=0.0003). No significant change in p120 protein was seen in either cell type.
  • TGF-beta1 mRNA rose about 2.2-fold in HPM cells given the inhibitor. It fell, reported as about 11-fold, in HMC given the mimic. TGF-beta1 protein was higher in inhibitor-treated HPM cells, but this was significant only against untransfected controls. The reduction in mimic-treated HMC was not significant.
  • Computer (bioinformatic) analysis found one potential miR-197-3p binding site in p120 and two in TGF-beta1. This was a prediction, not a laboratory test.
• The authors' conclusion: The authors concluded that miR-197-3p is upregulated in HPM cells and may be associated with enhanced clonogenic (colony-forming) capacity, possibly through proliferation-related pathways. They stated that its precise mechanistic contribution and functional significance remain to be fully defined.
• Limitations the authors state:
  • Changes at the mRNA level were not consistently reflected at the protein level, especially for p120, and only partially for TGF-beta1.
  • Direct binding of miR-197-3p to the target genes was not tested experimentally, and no rescue experiments were done. The proposed interactions are therefore putative.
  • Only one established cell line was used for each mesothelioma subtype. These lines may not reflect the biological variety of human pleural mesothelioma.
  • Cell cycle analysis, which the authors say would help clarify the proliferation findings, was not performed.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Prognosis, Mesothelial Cells, Apoptosis.

Related studies

• Epigenetic investigation into circulating microRNA 197-3p in sera from patients affected by malignant pleural mesothelioma and workers ex-exposed to asbestos — G. Di Mauro, F. Frontini, et al. (2023)
• Circulating microRNA-197-3p as a potential biomarker for asbestos exposure — F. Frontini, I. Bononi, et al. (2021)
• Downregulation of microRNA-34 induces cell proliferation and invasion of human mesothelial cells — N. Tanaka, S. Toyooka, et al. (2013)
• Overexpression of microRNA‑486 affects the proliferation and chemosensitivity of mesothelioma cell lines by targeting PIM1 — S. Pinelli, R. Alinovi, et al. (2021)
• Novel acridine-based agents with topoisomerase II inhibitor activity suppress mesothelioma cell proliferation and induce apoptosis — A. Raza, B.A. Jacobson, et al. (2012)
• Diffuse mesothelin expression leads to worse prognosis through enhanced cellular proliferation in colorectal cancer — S. Inoue, T. Tsunoda, et al. (2020)

Browse more research in Frontiers in Oncology, or return to medical research.