The impact of Charcot-Leyden Crystal protein on mesothelioma chemotherapy: targeting eosinophils for enhanced chemosensitivity

Our plain-English summary of The impact of Charcot-Leyden Crystal protein on mesothelioma chemotherapy: targeting eosinophils for enhanced chemosensitivity, by M. Willems, M. Hamaidia, A. Fontaine, et al (EBioMedicine, 2024).

The study

• Authors: M. Willems, M. Hamaidia, A. Fontaine, M. Grégoire, L. Halkin, L. Vilanova Mañá, R. Terres, M. Jamakhani, S. Deshayes, Y. Brostaux, V. Heinen, R. Louis, B. Duysinx, D. Jean, E. Wasielewski, A. Scherpereel, C. Blanquart, L. Willems
• Journal: EBioMedicine
• Published: 2024;109:105418
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: In mesothelioma (MPM), clinical evidence indicates that the absolute eosinophil count negatively correlates with overall survival and response to standard chemotherapy. Since eosinophils poorly infiltrate MPM tumours, we hypothesised that endocrine rather than paracrine pathways mediate the therapeutic response. We thus studied the effect of eosinophil-associated factors on response to chemotherapy in mesothelioma.

Methods: The culture supernatant conditioned by primary human eosinophils was added to mesothelioma cells in presence of the standard chemotherapeutic regimen. The effectiveness of an anti-eosinophil treatment was evaluated in a preclinical model of C57BL/6 mice transplanted with mesothelioma tumour cells.

Findings: Supernatant of eosinophils differentiated from EOL1 cells or directly isolated from peripheral blood inhibited apoptosis induced by cisplatin and pemetrexed in 2D cultures and in spheroids. Transcriptomic analysis indicated that the anti-apoptotic effect mediated by eosinophils involved molecular interactions with the Charcot-Leyden Crystal protein or Galectin-10 (CLC-P/Gal10). The functional relevance of CLC-P/Gal10 was demonstrated by antibody-mediated depletion. Recombinant human CLC-P/Gal10 mimicked the anti-apoptotic activity of eosinophil-derived supernatants. In the mouse model, eosinophilia did not significantly affect tumour growth but altered the response to chemotherapy. Finally, pretreatment of eosinophilia with the anti-Siglec-F antibody before chemotherapy restored the effectiveness of the treatment.

Interpretation: This study provides a mechanistic rationale to clinical evidence correlating the poor outcome of patients with mesothelioma and with eosinophil-derived CLC-P/Gal10, opening new prospects for intervention in this fatal solid tumour.

Funding: Belgian Foundation against Cancer, Fonds National de la Recherche Scientifique (FNRS), Télévie, Foundation Léon Fredericq, ULiège.

Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.

In plain English

This laboratory study asked whether eosinophils, a type of white blood cell, change how mesothelioma cells respond to cisplatin plus pemetrexed chemotherapy. It did not study asbestos exposure. The authors added fluid from cultured eosinophils to pleural mesothelioma cell lines before chemotherapy. This fluid significantly reduced chemotherapy-induced cell death. Removing the protein Charcot-Leyden Crystal protein/galectin-10 (CLC-P/Gal10) from the fluid removed this effect, and adding the purified protein reduced cell death. In cells from three patients' tumours, the protein's effect varied, and one culture showed no response. In mice with mesothelioma tumours and raised eosinophil counts, tumours did not respond to chemotherapy. One dose of an anti-eosinophil antibody before chemotherapy brought eosinophil counts back to baseline and restored the response. In pleural fluid from patients, CLC-P/Gal10 levels (split at 123.8 ng/mL) were not linked to survival in the first year. After the first year, survival differed between the high and low groups (p = 0.0257), with higher levels linked to poorer survival. The authors concluded this gives preclinical evidence for anti-eosinophil treatment. They noted that no clear mouse version of CLC-P/Gal10 is known and that the fluid finding needs independent confirmation.

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 study: cell-culture experiments, an animal (mouse) experiment, and measurement of CLC-P/Gal10 in stored patient samples with survival analysis
• Who was studied: Two human pleural mesothelioma cell lines: M14K (epithelioid) and ZL34 (biphasic). Three low-passage primary cultures from patients' tumours. Eosinophils made from the EOL1 cell line or isolated from healthy donors' blood. Fifty-four C57BL/6 mice inoculated with AK7 epithelioid mesothelioma cells. Patients with mesothelioma in France: sera (n = 39) and pleural effusions (n = 81), plus 20 control samples. Tumour biopsies from the Liege hospital biobank.
• Exposure: Not asbestos. The study tested eosinophil culture supernatant and recombinant CLC-P/Gal10, given before chemotherapy with 10 μM cisplatin plus 10 μM pemetrexed (C + P) in cells. In mice, eosinophilia was induced with IL-5 and/or IL-33, and eosinophils were depleted with an anti-Siglec-F antibody before cisplatin and pemetrexed.
• Main results:
  • In M14K cells, pre-incubation with supernatant from differentiated EOL1 eosinophils significantly reduced the cell death caused by cisplatin plus pemetrexed (p < 0.0001).
  • When CLC-P/Gal10 was removed from the eosinophil supernatant, the supernatant no longer reduced chemotherapy-induced cell death in M14K cells.
  • Adding recombinant human CLC-P/Gal10 (1 and 5 μg/ml) reduced chemotherapy-induced cell death in M14K cells at both doses.
  • Supernatant from eosinophils isolated from healthy donors' blood reduced chemotherapy-induced cell death in M14K cells (6 independent experiments, p = 0.0006). Removing CLC-P/Gal10 reversed this effect (p = 0.0011).
  • Eosinophil supernatant and CLC-P/Gal10 significantly increased the proportion of M14K cells that became senescent (stopped dividing) after chemotherapy.
  • In three primary cultures from patients' tumours, CLC-P/Gal10 affected cell death differently. MPM_07 (epithelioid) showed a dose-dependent decrease. MPM_80 (sarcomatoid) showed a reduction up to 1 μg/mL, then no effect at higher concentrations. MPM_27 (biphasic) showed no response.
  • In patients' tumour biopsies, eosinophils were present but infrequent.
  • In patients' pleural fluid, CLC-P/Gal10 level was split at 123.8 ng/mL. In the first year of survival, the level did not correlate with survival (p = 0.87).
  • In a landmark analysis of survival after the first year, patients above and below 123.8 ng/mL of CLC-P/Gal10 in pleural fluid had significantly different overall survival (p = 0.0257). The authors reported that multivariate analysis found no other prognostic factor and treated CLC-P/Gal10 as an independent prognostic factor.
  • The authors describe higher CLC-P/Gal10 levels in pleural fluid as correlating with poor survival.
  • In mice, the cytokines IL-5 and IL-33 used to raise eosinophil counts did not significantly change tumour growth.
  • In mice with raised blood eosinophils, mesothelioma tumours did not respond to cisplatin plus pemetrexed (p < 0.0001, f2 = 1.382).
  • In mice with raised eosinophils, a single dose of anti-Siglec-F antibody two days before chemotherapy brought eosinophil counts back to baseline. It also restored the tumours' response to cisplatin plus pemetrexed (p < 0.0001, f2 = 3.034).
• The authors' conclusion: The authors concluded that, in cell cultures, CLC-P/Gal10 produced by eosinophils impaired the response of mesothelioma cells to chemotherapy. They also concluded that the mouse results provide preclinical evidence for an anti-eosinophil treatment to improve mesothelioma therapy, supporting further investigation in patients.
• Limitations the authors state:
  • The mouse version of human CLC-P/Gal10 has not been clearly identified.
  • The chemotherapy drugs behave differently in the body (pharmacokinetics) in mice and in humans.
  • The pleural fluid findings should be extended to independent patient cohorts.
  • Further experiments are needed to clarify the mechanism, particularly in primary cells.

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, Chemotherapy, Overall Survival, Apoptosis, Cisplatin, Pemetrexed (Alimta).

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• Enhanced apoptosis by pemetrexed and simvastatin in malignant mesothelioma and lung cancer cells by reactive oxygen species-dependent mitochondrial dysfunction and Bim induction — K.E. Hwang, Y.S. Kim, et al. (2014)
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