CRCINA, INSERM, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
Service d'Hématologie Clinique, Unité d'Investigation Clinique, CHU, Nantes, France.
J Hematol Oncol. 2018 Dec 13;11(1):137. doi: 10.1186/s13045-018-0679-0.
Human myeloma cell lines (HMCLs) are widely used for their representation of primary myeloma cells because they cover patient diversity, although not fully. Their genetic background is mostly undiscovered, and no comprehensive study has ever been conducted in order to reveal those details.
We performed whole-exon sequencing of 33 HMCLs, which were established over the last 50 years in 12 laboratories. Gene expression profiling and drug testing for the 33 HMCLs are also provided and correlated to exon-sequencing findings.
Missense mutations were the most frequent hits in genes (92%). HMCLs harbored between 307 and 916 mutations per sample, with TP53 being the most mutated gene (67%). Recurrent bi-allelic losses were found in genes involved in cell cycle regulation (RB1, CDKN2C), the NFκB pathway (TRAF3, BIRC2), and the p53 pathway (TP53, CDKN2A). Frequency of mutations/deletions in HMCLs were either similar to that of patients (e.g., DIS3, PRDM1, KRAS) or highly increased (e.g., TP53, CDKN2C, NRAS, PRKD2). MAPK was the most altered pathway (82% of HMCLs), mainly by RAS mutants. Surprisingly, HMCLs displayed alterations in epigenetic (73%) and Fanconi anemia (54%) and few alterations in apoptotic machinery. We further identified mutually exclusive and associated mutations/deletions in genes involved in the MAPK and p53 pathways as well as in chromatin regulator/modifier genes. Finally, by combining the gene expression profile, gene mutation, gene deletion, and drug response, we demonstrated that several targeted drugs overcome or bypass some mutations.
With this work, we retrieved genomic alterations of HMCLs, highlighting that they display numerous and unprecedented abnormalities, especially in DNA regulation and repair pathways. Furthermore, we demonstrate that HMCLs are a reliable model for drug screening for refractory patients at diagnosis or at relapse.
人骨髓瘤细胞系（HMCLs）因其能够代表原发性骨髓瘤细胞而被广泛应用，尽管它们不能完全涵盖患者的多样性。它们的遗传背景在很大程度上尚未被发现，也从未进行过全面的研究来揭示这些细节。
我们对 33 株 HMCLs 进行了全外显子组测序，这些细胞系是在过去 50 年中由 12 个实验室建立的。还提供了 33 株 HMCLs 的基因表达谱和药物测试，并与外显子组测序结果相关联。
错义突变是基因中最常见的突变（92%）。每个样本中 HMCLs 携带 307 到 916 个突变，TP53 是突变最多的基因（67%）。在细胞周期调节（RB1、CDKN2C）、NFκB 通路（TRAF3、BIRC2）和 p53 通路（TP53、CDKN2A）相关基因中发现了复发性双等位基因缺失。HMCLs 中的突变/缺失频率要么与患者相似（例如，DIS3、PRDM1、KRAS），要么显著增加（例如，TP53、CDKN2C、NRAS、PRKD2）。MAPK 是最常改变的通路（82%的 HMCLs），主要是通过 RAS 突变体。令人惊讶的是，HMCLs 显示了表观遗传（73%）和范可尼贫血（54%）的改变，而凋亡机制的改变较少。我们进一步鉴定了 MAPK 和 p53 通路以及染色质调节/修饰基因中相互排斥和相关的突变/缺失。最后，通过结合基因表达谱、基因突变、基因缺失和药物反应，我们证明了几种靶向药物可以克服或绕过一些突变。
通过这项工作，我们获取了 HMCLs 的基因组改变，突出显示了它们存在许多前所未有的异常，特别是在 DNA 调节和修复途径中。此外，我们证明 HMCLs 是诊断或复发时难治性患者药物筛选的可靠模型。
