Molecular profiling reveals primary mesothelioma cell lines recapitulate human disease

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.

The Biology of Malignant Mesothelioma and the Relevance of Preclinical Models

“…The advantages and limitations of the mesothelioma preclinical models are presented in Table 1. (62,67,68). One study discussed the limits of these cell models.…”

“…One study discussed the limits of these cell models. The authors found strong molecular differences between primary and commercial cell lines (67), mainly due to a high number of divisions after their establishment, and thus an increased risk of new karyotypic changes. These models remain interesting for screening and preliminary investigations.…”

“…These models remain interesting for screening and preliminary investigations. Primary tumor cells represent an intriguing alternative because they share similar molecular characteristic with the primary tumor, even though they show a reduction of subclonal diversity (15,42,67). However, the necessity to perform studies before 6-10 passages limits the number of experiments.…”

Molecular and Histopathological Characterization of the Tumor Immune Microenvironment in Advanced Stage of Malignant Pleural Mesothelioma

“…[7][8][9] In preclinical models of primary or commercially available MPM cell lines, transcriptome and metabolic profiles have been found to be highly variable. 10 Marked genomic instability was observed from MPM tissue, and the interpatient variability was confirmed by the observation of multiple p53 isoforms in primary cell lines established from MPM tissue. These findings are consistent with the tumor protein p53 gene (TP53) being rarely inactivated in MPM.…”

Chemical Profiling of Primary Mesothelioma Cultures Defines Subtypes with Different Expression Profiles and Clinical Responses

“…This trial stresses the need for in vitro drug testing conditions that reflect genuine mesothelioma tumors more accurately. Primary mesothelioma cultures may provide a valuable model for personalized drug selection for patients with mesothelioma because they recapitulate the original tumor far more accurately than long-established MPM cell lines (21,22).…”