TGF-β Inhibition Through Combinatory Strategies Suppresses Proliferation and Invasiveness in Malignant Pleural Mesothelioma

Our plain-English summary of TGF-β Inhibition Through Combinatory Strategies Suppresses Proliferation and Invasiveness in Malignant Pleural Mesothelioma, by V. Ramundo, M.L. Palazzo, S. Lignola, et al (International Journal of Molecular Sciences, 2026).

The study

• Authors: V. Ramundo, M.L. Palazzo, S. Lignola, D. Raimondo, J. Kopecka, E. Aldieri
• Journal: International Journal of Molecular Sciences
• Published: 2026;27(5)
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor associated with asbestos exposure, which represents a current problem. MPM is characterized by a poor prognosis and an unsatisfactory therapeutic approach. Therefore, improving MPM prognosis is the real challenge for research today. Regarding preclinical data, Transforming Growth Factor-β (TGF-β) plays a crucial role in cancer, and its alteration has been associated with tumor progression and invasiveness, in particular through the Epithelial to Mesenchymal Transition (EMT) event. We investigated the role of TGF-β inhibition in proliferation, cell cycle, migration, and invasiveness in human MPM cells. Data obtained clearly highlighted how TGF-β inhibition, through the silencing or treatment of MPM cells with antibody anti-TGF-β (Fresolimumab), significantly reduces cell proliferation (MTT, PCNA) and prevents metastasis, reducing EMT and decreasing the invasiveness and migration of MPM cells. Finally, we also evaluated TGF-β inhibitory effects in 3D MPM cellular models (spheroids), highlighting a significant slowdown in the growth rate of spheroids treated with anti-TGF-β antibody or Fresolimumab, confirming the results previously obtained. Taken as a whole, targeting TGF-β will represent a starting point for future improvements in MPM management. This is particularly important as we foresee a growing increase in MPM in the coming years.

In plain English

This was a laboratory study of human malignant pleural mesothelioma (MPM) cells grown in culture. No patients or animals were treated, and the cells were not exposed to asbestos during the study. The authors, at the University of Torino, Italy, used one commercial cell line (MSTO-211H) and three cell lines derived from patients' tumors, one each of the epithelioid, biphasic and sarcomatoid types. They blocked a growth signal called TGF-β, either by silencing its gene or with antibodies, including the drug Fresolimumab. Adding TGF-β increased growth of MSTO-211H cells. Silencing it reduced growth in all the cell lines. In MSTO-211H cells, silencing also reduced cell movement and left more cells halted at one stage of division. Blocking TGF-β raised E-cadherin, a marker the authors linked to a less aggressive cell type. In small three-dimensional cell clusters (spheroids), the antibody or Fresolimumab reduced growth rates by more than half. The authors reported that Fresolimumab and silencing acted synergistically. The authors concluded that TGF-β is a promising marker and treatment target. They described their evidence as laboratory evidence that still needs testing in living organisms.

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) experiments on human mesothelioma cell lines, including 3D spheroid cultures
• Who was studied: Human MPM cell lines: commercial MSTO-211H (biphasic, from ATCC) and patient-derived MM404 (epithelioid), MM421 (biphasic) and MM432 (sarcomatoid) from the Biological Bank of Mesothelioma, Alessandria, Italy. Experiments were repeated three times. The number of patients behind the cell lines is not stated beyond the three patient-derived lines.
• Exposure: No asbestos exposure was studied. The cells received several treatments: TGF-β inhibition by siRNA silencing (20 nM in the methods, 60 nM in the figure legends); an anti-TGF-β antibody; Fresolimumab (antibody and Fresolimumab both at 14 nM per the methods); or a combination. Some cells were instead given added TGF-β (1-2 ng/mL).
• Main results:
  • In MSTO-211H cells, added TGF-β increased proliferation, while TGF-β silencing significantly inhibited proliferation compared with untreated cells.
  • In the three patient-derived cell lines, TGF-β silencing significantly reduced proliferation (PCNA) and cell viability in all histotypes, slightly more in the biphasic line.
  • In MSTO-211H cells, TGF-β silencing significantly reduced migration and increased the number of cells arrested in the S phase of the cell cycle.
  • siRNA silencing and the combined siRNA plus Fresolimumab treatment markedly increased E-cadherin, which the authors interpreted as partial reversal of EMT. Fibronectin decreased, with the effect differing by histotype.
  • In spheroids, the anti-TGF-β antibody or Fresolimumab significantly reduced growth compared with untreated spheroids.
  • The authors reported a synergistic effect between Fresolimumab and siRNA treatment on spheroid growth.
  • The authors reported that siRNA suppression was more pronounced than antibody neutralization.
  • The authors reported that reduced spheroid growth occurred without evidence of cell death.
• The authors' conclusion: The authors concluded that their findings support TGF-β as both a promising prognostic marker and a viable therapeutic target in MPM.
• Limitations the authors state:
  • The evidence is preclinical and in vitro only, and needs future in vivo validation.
  • Several aspects of the molecular mechanisms remain unexplained.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Prognosis, Metastasis.

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