Molecular profiling reveals primary mesothelioma cell lines recapitulate human disease

Our plain-English summary of Molecular profiling reveals primary mesothelioma cell lines recapitulate human disease, by T. Chernova, X.M. Sun, I.R. Powley, et al (Cell Death and Differentiation, 2016).

The study

• Authors: T. Chernova, X.M. Sun, I.R. Powley, S. Galavotti, S. Grosso, F.A. Murphy, G.J. Miles, L. Cresswell, A.V. Antonov, J. Bennett, A. Nakas, D. Dinsdale, K. Cain, M. Bushell, A.E. Willis, M. MacFarlane
• Journal: Cell Death and Differentiation
• Published: 2016;23(7):1152-64
• Cited by: 45 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant mesothelioma (MM) is an aggressive, fatal tumor strongly associated with asbestos exposure. There is an urgent need to improve MM patient outcomes and this requires functionally validated pre-clinical models. Mesothelioma-derived cell lines provide an essential and relatively robust tool and remain among the most widely used systems for candidate drug evaluation. Although a number of cell lines are commercially available, a detailed comparison of these commercial lines with freshly derived primary tumor cells to validate their suitability as pre-clinical models is lacking. To address this, patient-derived primary mesothelioma cell lines were established and characterized using complementary multidisciplinary approaches and bioinformatic analysis. Clinical markers of mesothelioma, transcriptional and metabolic profiles, as well as the status of p53 and the tumor suppressor genes CDKN2A and NF2, were examined in primary cell lines and in two widely used commercial lines. Expression of MM-associated markers, as well as the status of CDKN2A, NF2, the 'gatekeeper' in MM development, and their products demonstrated that primary cell lines are more representative of the tumor close to its native state and show a degree of molecular diversity, thus capturing the disease heterogeneity in a patient cohort. Molecular profiling revealed a significantly different transcriptome and marked metabolic shift towards a greater glycolytic phenotype in commercial compared with primary cell lines. Our results highlight that multiple, appropriately characterised, patient-derived tumor cell lines are required to enable concurrent evaluation of molecular profiles versus drug response. Furthermore, application of this approach to other difficult-to-treat tumors would generate improved cellular models for pre-clinical evaluation of novel targeted therapies.

In plain English

This was a laboratory study of mesothelioma cell lines. The authors grew eight new cell lines from tumors removed by pleural surgery from patients with advanced epithelioid (six) or biphasic (two) malignant mesothelioma. Five patients had occupational asbestos exposure and three had no known exposure. The authors compared these primary lines with two widely used commercial lines, MSTO-211H and NCI-H2052, and with normal mesothelial cells. Seven of the eight primary lines had lost both copies of the p16INK4A and p14ARF genes. All primary lines except MESO-27T lacked the protein Merlin. In MESO-27T, Merlin was present but chemically altered in a way the authors described as functionally inactive. In gene-activity analyses, the commercial lines grouped separately from the primary lines. The commercial lines showed four- to five-fold higher glycolysis and two- to four-fold higher oxygen consumption than the primary lines. The authors concluded that primary cell lines are superior models for testing new treatments and that long-established commercial lines have limited suitability. They noted that flat (2D) cultures lack the complexity of real tumors and that some genetic changes may have arisen in culture.

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 establishing and characterising patient-derived mesothelioma cell lines and comparing them with commercial cell lines
• Who was studied: Eight cell lines grown from surgically resected tumors of eight patients with advanced malignant mesothelioma: six epithelioid and two biphasic. Seven patients were male and one female, aged 56 to 78. Surgery was pleural decortication or pleurectomy. These were compared with commercial lines MSTO-211H and NCI-H2052 and with normal human omental mesothelial cells. The authors are based in Leicester, UK; dates of collection are not given.
• Exposure: Asbestos exposure history of the patients was recorded but was not the subject of analysis. Five had occupational exposure, including a kitchen fitter and carpenter, a building contractor, building trade work cutting asbestos sheets, a carpenter, and a tin box factory worker. Three had no known exposure. Fiber types are not stated.
• Main results:
  • Homozygous deletion of p16INK4A and p14ARF was found in seven of eight patient-derived cell lines, all except MESO-27T.
  • All primary cell lines except MESO-27T were negative for the NF2-encoded protein Merlin. Commercial line MSTO-211H expressed high levels of Merlin and NCI-H2052 expressed low levels.
  • In MESO-27T, Merlin was phosphorylated, which the authors stated makes it functionally inactive.
  • In gene expression clustering, the commercial cell lines clustered together and separately from the primary cell lines.
  • Both commercial cell lines had four- to five-fold higher glycolysis rates than the primary cells.
  • Oxygen consumption rates were two- to four-fold higher in the commercial lines than in the primary cells.
  • The primary cell lines showed positive cell-surface Podoplanin staining, although MESO-3T expressed low levels. MSTO-211H was Podoplanin-negative.
  • Of the top 100 genes associated with survival in a breast cancer data set (METABRIC), 32 were among the genes aberrantly expressed in the primary mesothelioma cell lines. The expected number was two, and the odds ratio of enrichment was 15.99.
  • Genetic profiles of some cell lines differed from the original tumors. MESO-7T and MESO-27T had four and three loci changed, respectively.
• The authors' conclusion: The authors concluded that patient-derived primary cell lines are superior models for translating pre-clinical findings to the clinic, and that long-established commercial lines have limited suitability for translational research.
• Limitations the authors state:
  • Flat (2D) cell cultures lack the architectural and cellular complexity of real tumors.
  • Loss of CDKN2A/p16 may have occurred as cells adapted to culture rather than in the original tumor.
  • The authors could not fully rule out that the genetic changes seen in MESO-7T existed before the cells were isolated.
  • Tissue from early-stage mesothelioma was not available; all tumors were advanced.

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: Molecular Profiling, Mesothelioma, Malignant Mesothelioma, Asbestos Exposure, Multidisciplinary Team, Tumor Suppressor Gene, CDKN2A.

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