Transcriptional profiling and assessment of cell lines as in vitro models for mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive malignancy and new treatment modalities must be established to increase patient survival time. In the search for new therapeutic targets, reliable and well-characterised in vitro models are essential. In this study, we have characterised three MCL cell lines (SP53, Granta 519 and NCEB1) in comparison with primary tumours from MCL, follicular lymphomas (FL), a FL cell line (RL), a Burkitt lymphoma cell line (RAJI) and five different B cell populations from healthy individuals. Expression profiling was used to determine the relative expression of >12000 transcripts in these samples, and flow cytometry analysis was performed to establish a phenotypic signature for each of the cell lines. In addition, the cell lines were sequenced, and the frequency of somatic mutations and immunoglobulin (Ig) variable heavy chain (VH) usage were determined. We show by hierarchical clustering that the cell lines retain a genetic signature similar to primary MCL, which readily separated the MCL samples from the other lymphoma cell lines and the FL tumours. Furthermore, the MCL cell lines showed differences in the frequency of VH somatic mutations (0-2.1%). The increased number of mutations in NCEB1, compared to the other MCL cell lines, was in agreement with a decreased expression of CD31, CD44, CXCR5, CCR7 and CCR6. Taken together, our data show that the cell lines are clearly derived from MCL tumours and expressed similar genetic and phenotypic signatures compared to primary tumours, which confirmed their usefulness as in vitro models.