Intercellular interaction dictates cancer cell ferroptosis via NF2-YAP signalling

Our plain-English summary of Intercellular interaction dictates cancer cell ferroptosis via NF2-YAP signalling, by J. Wu, A.M. Minikes, M. Gao, et al (Nature, 2019).

The study

• Authors: J. Wu, A.M. Minikes, M. Gao, H. Bian, Y. Li, B.R. Stockwell, Z.N. Chen, X. Jiang
• Journal: Nature
• Published: 2019;572(7769):402-406
• Cited by: 948 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Ferroptosis, a cell death process driven by cellular metabolism and iron-dependent lipid peroxidation, has been implicated in diseases such as ischaemic organ damage and cancer1,2. The enzyme glutathione peroxidase 4 (GPX4) is a central regulator of ferroptosis, and protects cells by neutralizing lipid peroxides, which are by-products of cellular metabolism. The direct inhibition of GPX4, or indirect inhibition by depletion of its substrate glutathione or the building blocks of glutathione (such as cysteine), can trigger ferroptosis3. Ferroptosis contributes to the antitumour function of several tumour suppressors such as p53, BAP1 and fumarase4-7. Counterintuitively, mesenchymal cancer cells-which are prone to metastasis, and often resistant to various treatments-are highly susceptible to ferroptosis8,9. Here we show that ferroptosis can be regulated non-cell-autonomously by cadherin-mediated intercellular interactions. In epithelial cells, such interactions mediated by E-cadherin suppress ferroptosis by activating the intracellular NF2 (also known as merlin) and Hippo signalling pathway. Antagonizing this signalling axis allows the proto-oncogenic transcriptional co-activator YAP to promote ferroptosis by upregulating several ferroptosis modulators, including ACSL4 and TFRC. This finding provides mechanistic insights into the observations that cancer cells with mesenchymal or metastatic property are highly sensitive to ferroptosis8. Notably, a similar mechanism also modulates ferroptosis in some non-epithelial cells. Finally, genetic inactivation of the tumour suppressor NF2, a frequent tumorigenic event in mesothelioma10,11, rendered cancer cells more sensitive to ferroptosis in an orthotopic mouse model of malignant mesothelioma. Our results demonstrate the role of intercellular interactions and intracellular NF2-YAP signalling in dictating ferroptotic death, and also suggest that malignant mutations in NF2-YAP signalling could predict the responsiveness of cancer cells to future ferroptosis-inducing therapies.

In plain English

This laboratory study used human cancer cell lines and mice to examine ferroptosis, a form of cell death driven by iron-dependent damage to cell fats. It did not study asbestos or people. In HCT116 colon cancer cells, reducing E-cadherin, NF2, LATS1 and LATS2 made cells more sensitive to ferroptosis. Of ten patient-derived malignant mesothelioma cell lines, four had normal NF2. After ferroptosis was triggered by cystine starvation or the drug erastin, several NF2-mutant lines showed strong ferroptosis even when crowded; restoring NF2 in one mutant line reduced this. The authors linked the effect to the protein YAP raising TFRC and ACSL4. In nude mice (8 per group), switching off the GPX4 gene made tumours from NF2-reduced mesothelioma cells shrink, while control tumours only grew more slowly. In mice with tumours placed in the chest (pleural cavity), switching off GPX4 slowed NF2-reduced tumours and reduced their spread (metastasis), while control tumours were unaffected. The authors concluded that NF2 status might help predict mesothelioma metastasis and response to ferroptosis-inducing treatment. Unless stated otherwise, experiments were not randomized or blinded.

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 on human cancer cell lines (including malignant mesothelioma lines), plus mouse experiments with tumours grown under the skin and an orthotopic (chest-cavity) mouse model of pleural mesothelioma
• Who was studied: A panel of human epithelial cancer cell lines (mainly HCT116 colon cancer cells), ten patient-derived human malignant mesothelioma cell lines (four with wild-type NF2, six NF2-defective), mouse embryonic fibroblasts, and female athymic nude mice and NOD/SCID mice carrying implanted tumours (8 per group in the subcutaneous mesothelioma model; 6 or 7 per group in the orthotopic model)
• Exposure: No asbestos exposure was studied. The experimental conditions were cell density, reduction or loss of E-cadherin, NF2, LATS1 and LATS2 or YAP, and ferroptosis-inducing treatments (cystine starvation, erastin, RSL3, Dox-induced GPX4 knockout, imidazole ketone erastin (IKE), sorafenib)
• Main results:
  • In HCT116 colon cancer cells, knockdown of E-cadherin, NF2, LATS1 and LATS2 increased sensitivity to ferroptosis in culture and in 3D spheroids
  • Among the mesothelioma cell lines, after ferroptosis was induced (cell death measured after cystine starvation, and spheroid viability after erastin), several NF2-mutant lines underwent potent ferroptosis even at the highest density tested and in spheroids, while NF2 wild-type lines were relatively insensitive
  • The cell death in the mesothelioma cell-line density experiments was measured after cystine starvation
  • In NF2-defective Meso33 mesothelioma cells, switching NF2 back on (Dox-induced) inhibited ferroptosis at high density and in spheroids
  • The ferroptosis-related proteins TFRC and ACSL4 were increased by loss of E-cadherin, NF2 knockdown or active YAP, and the authors identified them as targets of the YAP-TEAD complex
  • In nude mice with subcutaneous tumours from 211H mesothelioma cells (n = 8 per group), Dox-induced GPX4 knockout made NF2-knockdown tumours recede, while control (shNT) tumours only showed slower growth
  • In nude mice with HCT116 colon cancer tumours (n = 6 per group), knockdown of LATS1 and LATS2 made tumours significantly more sensitive to IKE
  • In the orthotopic (intrapleural) mesothelioma model, Dox reduced growth of NF2-knockdown tumours while control tumours were unaffected
  • In the orthotopic model, GPX4 knockout reduced the metastatic capability of NF2-knockdown tumours
• The authors' conclusion: The authors concluded that NF2 status might be useful as a biomarker to predict mesothelioma metastasis and responsiveness to treatments that induce ferroptotic cell death
• Limitations the authors state:
  • No statistical methods were used to set sample size, and unless stated otherwise experiments were not randomized and investigators were not blinded
  • Raising TFRC and ACSL4 together did not fully restore ferroptosis in crowded cells, which the authors took to suggest that other YAP target genes are also involved

Topics

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

Medical terms in this study, explained in our Lexicon: Glutathione (GSH), BAP1, Metastasis, Merlin, Malignant Mesothelioma.

Related studies

• Immunohistochemistry for NF2, LATS1/2, and YAP/TAZ Fails to Separate Benign From Malignant Mesothelial Proliferations — B.S. Sheffield, J. Lorette, et al. (2016)
• Hippo pathway gene mutations in malignant mesothelioma: revealed by RNA and targeted exon sequencing — A. Miyanaga, M. Masuda, et al. (2015)
• The YAP1 Signaling Inhibitors, Verteporfin and CA3, Suppress the Mesothelioma Cancer Stem Cell Phenotype — S. Kandasamy, G. Adhikary, et al. (2020)
• Targeting YAP in malignant pleural mesothelioma — W.Q. Zhang, Y.Y. Dai, et al. (2017)
• LIM-domain protein AJUBA suppresses malignant mesothelioma cell proliferation via Hippo signaling cascade — I. Tanaka, H. Osada, et al. (2015)
• The Emerging Role of the Hippo Pathway in Lung Cancers: Clinical Implications — S.L. Teoh, S. Das (2017)

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