Department of Rheumatology, First Hospital of Jilin University, Changchun, 130021, China.
Laboratory of Immunology, Institute of Basic Medical Sciences, P.O. Box 130 (3), Taiping Road #27, Beijing, 100850, China.
BMC Cancer. 2019 Jul 16;19(1):700. doi: 10.1186/s12885-019-5848-1.
Multiple myeloma (MM), characterized by cancerous proliferation of plasmablasts (PB) and plasma cells (PC), remains incurable in many patients. Differentially expressed molecules between MM PCs and healthy PCs have been explored in order to identify novel targets for treating MM. In the present study, we searched for novel MM therapeutic targets by comparing mRNA expression patterns between the Mus musculus myeloma plasmablast-like SP 2/0 cell line and LPS-induced PB/PC.
Gene expression profiles of LPS-induced PB/PC and SP 2/0 cells were determined using RNA-sequencing. A predicted gene (Gm40600) was found to be expressed at a low level in SP 2/0 cells. To study the role of Gm40600 in malignant PC, Gm40600 cDNA was cloned into a lentiviral vector (LV201) containing a puromycin selectable marker that was then transfected into SP 2/0 cells. Stable Gm40600-expressing SP 2/0 cells were selected using puromycin. The effect of Gm40600 on SP 2/0 cell proliferation, cell cycle/apoptosis, and tumor progression was assessed by cell counting kit-8 (CCK8), flow cytometry (FACS), and the SP 2/0 isograft mouse model, respectively. The effect of Gm40600 on mRNA and protein expression was evaluated by RNA-sequencing and western blotting, respectively.
We found that SP 2/0 cells expressed lower level of Gm40600 mRNA as compared to LPS-induced PB/PC. Overexpression of Gm40600 significantly suppressed SP 2/0 cell proliferation and isograft tumor progression in an isograft mouse model by promoting apoptosis. In addition, Gm40600 overexpression suppressed transcription of the gene encoding Bcl2. Gm40600 overexpression also reduced the expression of PC-associated transcription factors Blimp1 and Xbp1, which promote transcription of the gene that encodes Bcl2.
Gm40600 reduced SP 2/0 cell proliferation and isograft tumor growth and progression by suppressing Blimp1 and Xbp1-mediated Bcl2 transcription to induce apoptosis. Thus, regulation of a human homolog of Gm40600, or associated factors, may be a potential therapeutic approach for treating MM.
多发性骨髓瘤（MM）的特征是浆母细胞（PB）和浆细胞（PC）的癌变增殖，在许多患者中仍然无法治愈。为了寻找治疗 MM 的新靶点，已经探索了 MM 中 PC 和健康 PC 之间差异表达的分子。在本研究中，我们通过比较脂多糖诱导的 PB/PC 和 SP 2/0 骨髓瘤浆母细胞样细胞系的 mRNA 表达谱，寻找新的 MM 治疗靶点。
采用 RNA-seq 技术检测 LPS 诱导的 PB/PC 和 SP 2/0 细胞的基因表达谱。发现一个预测基因（Gm40600）在 SP 2/0 细胞中低表达。为了研究 Gm40600 在恶性 PC 中的作用，将 Gm40600 cDNA 克隆到含有嘌呤霉素选择标记的慢病毒载体（LV201）中，然后转染到 SP 2/0 细胞中。用嘌呤霉素筛选稳定表达 Gm40600 的 SP 2/0 细胞。通过细胞计数试剂盒-8（CCK8）、流式细胞术（FACS）和 SP 2/0 同系移植小鼠模型分别评估 Gm40600 对 SP 2/0 细胞增殖、细胞周期/凋亡和肿瘤进展的影响。通过 RNA-seq 和 Western blot 分别评估 Gm40600 对 mRNA 和蛋白表达的影响。
我们发现 SP 2/0 细胞的 Gm40600 mRNA 表达水平明显低于 LPS 诱导的 PB/PC。过表达 Gm40600 通过促进细胞凋亡，显著抑制 SP 2/0 细胞增殖和同系移植小鼠模型中的肿瘤进展。此外，Gm40600 过表达抑制了编码 Bcl2 的基因的转录。Gm40600 过表达还降低了与 PC 相关的转录因子 Blimp1 和 Xbp1 的表达，这促进了编码 Bcl2 的基因的转录。
Gm40600 通过抑制 Blimp1 和 Xbp1 介导的 Bcl2 转录诱导细胞凋亡，从而减少 SP 2/0 细胞增殖和同系移植肿瘤生长和进展。因此，调节 Gm40600 的人同源物或相关因子可能是治疗 MM 的一种潜在治疗方法。
