Complexity of progranulin mechanisms of action in mesothelioma

Our plain-English summary of Complexity of progranulin mechanisms of action in mesothelioma, by E. Ventura, C. Xie, S. Buraschi, et al (Journal of Experimental & Clinical Cancer Research, 2022).

The study

• Authors: E. Ventura, C. Xie, S. Buraschi, A. Belfiore, R.V. Iozzo, A. Giordano, A. Morrione
• Journal: Journal of Experimental & Clinical Cancer Research
• Published: 2022;41(1):333
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Mesothelioma is an aggressive disease with limited therapeutic options. The growth factor progranulin plays a critical role in several cancer models, where it regulates tumor initiation and progression. Recent data from our laboratories have demonstrated that progranulin and its receptor, EphA2, constitute an oncogenic pathway in bladder cancer by promoting motility, invasion and in vivo tumor formation. Progranulin and EphA2 are expressed in mesothelioma cells but their mechanisms of action are not well defined. In addition, there are no data establishing whether the progranulin/EphA2 axis is tumorigenic for mesothelioma cells.

Methods: The expression of progranulin in various mesothelioma cell lines derived from all major mesothelioma subtypes was examined by western blots on cell lysates, conditioned media and ELISA assays. The biological roles of progranulin, EphA2, EGFR, RYK and FAK were assessed in vitro by immunoblots, human phospho-RTK antibody arrays, pharmacological (specific inhibitors) and genetic (siRNAs, shRNAs, CRISPR/Cas9) approaches, motility, invasion and adhesion assays. In vivo tumorigenesis was determined by xenograft models. Focal adhesion turnover was evaluated biochemically using focal adhesion assembly/disassembly assays and immunofluorescence analysis with focal adhesion-specific markers.

Results: In the present study we show that progranulin is upregulated in various mesothelioma cell lines covering all mesothelioma subtypes and is an important regulator of motility, invasion, adhesion and in vivo tumor formation. However, our results indicate that EphA2 is not the major functional receptor for progranulin in mesothelioma cells, where progranulin activates a complex signaling network including EGFR and RYK. We further characterized progranulin mechanisms of action and demonstrated that progranulin, by modulating FAK activity, regulates the kinetic of focal adhesion disassembly, a critical step for cell motility.

Conclusion: Collectively, our results highlight the complexity of progranulin oncogenic signaling in mesothelioma, where progranulin modulate functional cross-talks between multiple RTKs, thereby suggesting the need for combinatorial therapeutic approaches to improve treatments of this aggressive disease.

© 2022. The Author(s).

In plain English

This was a laboratory study of the growth factor progranulin in mesothelioma, using cultured human cell lines and mouse xenografts; it did not study asbestos exposure or patients. The authors reported that progranulin was upregulated in the mesothelioma lines NCI-H2052, NCI-H2452, NCI-H28 and MSTO-211H compared with immortalized normal mesothelial MeT-5A cells, by immunoblot, conditioned media and ELISA. Deleting the progranulin gene (GRN) in MSTO-211H cells by CRISPR/Cas9 reduced migration in transwell assays, which re-expression of progranulin restored, and reduced invasion through matrigel, whereas deleting EphA2 changed neither migration nor invasion. In Rag2-/- mice, GRN knock-out cells formed tumors of significantly higher volume than parental or EphA2 knock-out cells. Antibody arrays showed progranulin stimulation increased tyrosine phosphorylation of EGFR, EphA7 and RYK in MSTO-211H cells and mainly RYK in NCI-H2052 cells, with no EphA2 tyrosine phosphorylation detected. Progranulin depletion raised pFAK Y397, an increase abolished by RYK knock-down, and GRN knock-out cells showed impaired focal adhesion disassembly. The authors concluded progranulin signaling in mesothelioma is complex and context-dependent.

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) study of human mesothelioma cell lines with mouse xenograft experiments
• Who was studied: Human mesothelioma cell lines NCI-H2052 and NCI-H2452 (sarcomatoid), NCI-H28 (epithelioid) and MSTO-211H (biphasic), compared with immortalized normal mesothelial MeT-5A cells; plus Rag2-/- mice implanted with MSTO-211H cells
• Exposure: Progranulin: recombinant human progranulin stimulation (10 or 50 nM) and genetic manipulation of GRN, EphA2, EphA7, RYK and FAK, plus inhibitors of EGFR (gefitinib), FAK (PF-573228), MEK1/2 (U0126) and AKT
• Main results:
  • Progranulin protein was higher in all four mesothelioma cell lines than in MeT-5A normal mesothelial cells, highest in NCI-H2452, NCI-H28 and MSTO-211H
  • In MSTO-211H cells, GRN knock-out reduced migration and re-expressing progranulin restored migratory capacity, while EphA2 knock-out did not affect migration
  • GRN knock-out MSTO-211H cells were less invasive through matrigel; parental and EphA2 knock-out cells invaded similarly
  • In MSTO-211H cells, GRN knock-out reduced adhesion to collagen while EphA2 knock-out increased adhesion to plasma fibronectin
  • In Rag2-/- mice, GRN knock-out MSTO-211H cells formed larger tumors than parental or EphA2 knock-out cells (N = 8)
  • On phospho-RTK arrays, progranulin increased phosphorylation of EGFR, EphA7 and RYK in MSTO-211H cells and of RYK (with minor EGFR change) in NCI-H2052 cells; EphA2 tyrosine phosphorylation was not detected
  • Progranulin depletion in MSTO-211H cells raised pFAK Y397, an increase abolished by RYK knock-down
  • GRN knock-out MSTO-211H cells showed impaired focal adhesion disassembly after nocodazole washout compared with parental cells
  • In NCI-H2052 cells, recombinant progranulin reduced migration rather than increasing it
• The authors' conclusion: The authors concluded that progranulin signaling in mesothelioma is complex and context-dependent, acting through multiple receptor tyrosine kinases rather than EphA2, and that combinatorial approaches might be needed if progranulin is targeted
• Limitations the authors state:
  • The authors said further experiments are needed to explain the differing effects of progranulin on motility in the two cell lines, which may depend on the mesothelioma subtype
  • The authors noted that pharmacological targeting of progranulin might differ in effect from genetic deletion
  • The authors stated it is not established whether progranulin interacts directly with RYK
  • RYK knock-down efficiency had to be checked by mRNA because reliable RYK antibodies were scarce

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, EGFR, Carcinogenesis.

Related studies

• Progranulin Oncogenic Network in Solid Tumors — E. Ventura, G. Ducci, et al. (2023)
• Proteomic (antibody microarray) exploration of the molecular mechanism of action of the specific COX-2 inhibitor DuP 697 — V. Agarwal, V.C. Hodgkinson, et al. (2013)
• Cephalomannine as in vitro and in vivo anticancer agent in mesothelioma cells: mechanisms of action — F. Morani, I. Dell'Anno, et al. (2025)
• The Mechanisms of Action of Tumor Treating Fields — J.C. Moser, E. Salvador, et al. (2022)
• Mechanisms of action of inhaled fibers, particles and nanoparticles in lung and cardiovascular diseases — B.T. Mossman, P.J. Borm, et al. (2007)
• Mechanisms of action of poorly soluble particulates in overload-related lung pathology — B.T. Mossman (2000)

Browse more research in Journal of Experimental & Clinical Cancer Research, or return to medical research.