Gene therapy for diffuse pleural mesotheliomas in preclinical models by concurrent expression of NF2 and SuperHippo

Our plain-English summary of Gene therapy for diffuse pleural mesotheliomas in preclinical models by concurrent expression of NF2 and SuperHippo, by R. Zhu, X. Liu, X. Zhang, et al (Cell Reports. Medicine, 2024).

The study

• Authors: R. Zhu, X. Liu, X. Zhang, Z. Zhong, S. Qi, R. Jin, Y. Gu, Y. Wang, C. Ling, K. Chen, D. Ye, F.X. Yu
• Journal: Cell Reports. Medicine
• Published: 2024;5(10):101763
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Diffuse pleural mesothelioma (DPM) is a lethal cancer with a poor prognosis and limited treatment options. The Hippo signaling pathway genes, such as NF2 and LATS1/2, are frequently mutated in DPM, indicating a tumor suppressor role in the development of DPM. Here, we show that in DPM cell lines lacking NF2 and in mice with a conditional Nf2 knockout, downregulation of WWC proteins, another family of Hippo pathway regulators, accelerates DPM progression. Conversely, the expression of SuperHippo, a WWC-derived minigene, effectively enhances Hippo signaling and suppresses DPM development. Moreover, the adeno-associated virus serotype 6 (AAV6) has been engineered to deliver both NF2 and SuperHippo genes into mesothelial cells, which substantially impedes tumor growth in xenograft and genetic DPM models and prolongs the median survival of mice. These findings serve as a proof of concept for the potential use of gene therapy targeting the Hippo pathway to treat DPM.

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

In plain English

This was a preclinical laboratory study (human mesothelioma cell lines plus genetically engineered mice) testing whether activating the Hippo pathway suppresses diffuse pleural mesothelioma (DPM). Reviewing TCGA data on 87 DPM specimens, the authors reported NF2 and LATS2 alterations in 31% and 11% of samples. CRISPR deletion of SAV1 or WWC1-3 in three DPM lines (NCI-H2452, NCI-H2373, NCI-H2052) activated YAP and increased colony formation; in subcutaneous xenografts, SAV1- or WWC1-3-deficient NCI-H2373 and NCI-H2052 cells grew faster than controls in nude mice. After intrathoracic Adeno-Cre, mice with combined Nf2 and Sav1 or Wwc1/Wwc2 deletion had median survivals of 292 and 264 days; Nf2;Trp53 mice lived about 125 days and adding Wwc1/2 deletion shortened this to about 80 days. A transgenic SuperHippo minigene raised survival of Nf2;Trp53 mice from 95 to 124 days. AAV6 carrying SuperHippo-P2A-NF2 injected into xenograft tumours slowed tumour growth and lowered tumour weight; given into the pleural cavity of Nf2;Trp53 mice, it reduced mesothelium thickening and prolonged survival. The authors concluded this is a proof of concept for Hippo-targeted gene therapy. Asbestos appeared only as background in the introduction.

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: Preclinical laboratory study: cell-line gene-editing experiments, mouse xenograft and genetically engineered mouse mesothelioma models, plus analysis of an existing public genomic dataset
• Who was studied: Three human DPM cell lines (NCI-H2452, NCI-H2052, NCI-H2373), nude mice bearing xenografts, conditional knockout mice (Nf2, Sav1, Wwc1/2, Trp53, SuperHippo transgene) in Shanghai, China; TCGA dataset of 87 DPM specimens
• Exposure: Genetic manipulation of Hippo pathway genes (deletion of SAV1, WWC1-3, Nf2, Trp53) and therapeutic expression of NF2, SuperHippo, or SuperHippo-P2A-NF2, delivered by lentivirus or AAV6
• Main results:
  • In the TCGA dataset of 87 DPM specimens, NF2 was altered in 31% and LATS2 in 11% of samples
  • Deleting SAV1 or WWC1-3 in the DPM cell lines lowered phosphorylated YAP and raised active (dephosphorylated) YAP
  • Cells lacking SAV1 or WWC1-3 showed greater clonogenic capacity than control DPM cells
  • In nude mouse xenografts, SAV1- or WWC1-3-deficient NCI-H2373 (printed once as NCI-H2372) and NCI-H2052 cells grew much faster than control cells, which grew poorly
  • Median survival after Adeno-Cre injection was 292 days for Nf2;Sav1 mice and 264 days for Nf2;Wwc1;Wwc2 mice, while single-gene-deficient mice lived more than 1 year
  • Nf2;Trp53 mice survived about 125 days; additional Wwc1/2 knockout shortened median survival to about 80 days
  • Transgenic SuperHippo expression in Nf2;Trp53 mice increased survival from 95 to 124 days
  • Intratumoral AAV6-SuperHippo-P2A-NF2 suppressed growth of WWC1-3 tKO NCI-H2052 xenografts (slower volume increase, lower tumour weight); survival was not reported for this experiment
  • Intrathoracic AAV6-SuperHippo-P2A-NF2 in Nf2;Trp53 mice reduced mesothelium thickening and Mesothelin, WT1 and Ki67 expression
  • Survival of Nf2;Trp53 mice treated intrathoracically with AAV6-SuperHippo-P2A-NF2 was prolonged compared with AAV6 control
  • No significant body-weight difference between AAV6-control and AAV6-SuperHippo-P2A-NF2 treated mice within 80 days of treatment
  • Single-agent Nf2 or SuperHippo therapy was less effective than the combined construct, judged by mesothelium thickness
• The authors' conclusion: The authors concluded that their results are a proof of concept for gene therapy targeting the Hippo pathway in DPM
• Limitations the authors state:
  • The authors stated the models used may not fully reflect the molecular heterogeneity of human DPM and that patient-derived xenograft models should be tested
  • The authors stated that efficacy where NF2 mutations co-occur with CDKN2A/B and BAP1 mutations still needs investigation
  • The authors stated the therapy is designed for YAP/TAZ-driven mesotheliomas and its effect in mesotheliomas without Hippo pathway inactivation remains to be tested
  • The authors noted that delivering AAV-based therapies to different tumour sites remains challenging because of anatomic features

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Prognosis, Hippo Signaling Pathway, Mesothelial Cells, Median Overall Survival.

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• Gene therapy using adenovirus carrying the herpes simplex-thymidine kinase gene to treat in vivo models of human malignant mesothelioma and lung cancer — H.C. Hwang, W.R. Smythe, et al. (1995)
• Efficacy of repeated adenoviral suicide gene therapy in a localized murine tumor model — E.S. Lambright, S.D. Force, et al. (2000)
• TAZ activation by Hippo pathway dysregulation induces cytokine gene expression and promotes mesothelial cell transformation — A. Matsushita, T. Sato, et al. (2019)
• Replication-restricted vaccinia as a cytokine gene therapy vector in cancer: persistent transgene expression despite antibody generation — S. Mukherjee, T. Haenel, et al. (2000)

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