PI3K/AKT inhibition reverses R-CHOP resistance by destabilizing SOX2 in diffuse large B cell lymphoma
PI3K/AKT inhibition reverses R-CHOP resistance by destabilizing SOX2 in diffuse large B cell lymphoma
复制标题
PI3K/AKT 抑制通过破坏弥漫性大 B 细胞淋巴瘤中 SOX2 的稳定性来逆转 R-CHOP 耐药性
DOI：
10.7150/thno.41362
复制
发表时间：
2020-01-01
期刊：
影响因子：
12.4
通讯作者：
Hu, Weiguo
中科院分区：
文献类型：
--
作者：
Chen, Jianfeng;Ge, Xiaowen;Hu, Weiguo
高达三分之一的弥漫性大B细胞淋巴瘤（DLBCL）患者最终对R-CHOP方案产生耐药，而其余治疗选择有限。因此，迫切需要了解潜在的机制和开发治疗方法。研究方法：我们建立了两个生殖中心B细胞样（GCB）和活化B细胞样（ABC）亚型R-CHO耐药DLBCL细胞系，通过连续移植评估其肿瘤启动能力，并通过流式细胞术或免疫印迹检测干细胞相关特征，包括CD 34和CD 133表达、侧群和ALDH 1活性。这些耐药细胞的表达谱通过RNA测序表征。通过体外CytoTox-glo测定和荷瘤小鼠中评估耐药细胞对不同治疗的敏感性。采用免疫组化法检测12例R-CHOP耐药DLBCL临床标本中SOX 2、CDK 6和FGFR 12的表达水平。结果：两种耐药DLBCL亚型中干细胞样CSC比例均显著增加。SOX 2表达水平在两种耐药细胞系中显著升高，这是由于其通过活化的PI 3 K/AKT信号转导而磷酸化，从而阻止了泛素介导的降解。此外，多种因素，包括BCR，整合素，趋化因子和FGFR 1/2信号转导，调节PI 3 K/AKT激活。GCB亚型中的CDK 6和ABC亚型中的FGFR 1/2是SOX 2靶点，其抑制有效地使抗性细胞对R-CHOP处理重新敏感。更重要的是，向R-CHOP中添加PI 3 K抑制剂完全抑制了R-CHO抗性DLBCL细胞的肿瘤生长，最有可能是通过将CSC转化为化学敏感的分化细胞。结论：PI 3 K/AKT/SOX 2轴在R-CHOP耐药发展中起着关键作用，本研究中提出的针对CSC的促分化疗法值得在临床试验中进一步研究以治疗耐药DLBCL。
Up to one-third of diffuse large B cell lymphoma (DLBCL) patients eventually develop resistance to R-CHOP regimen, while the remaining therapeutic options are limited. Thus, understanding the underlying mechanisms and developing therapeutic approaches are urgently needed. Methods: We generated two germinal center B cell-like (GCB) and activated B cell-like (ABC) subtype R-CHO resistant DLBCL cell lines, of which the tumor-initiating capacity was evaluated by serial-transplantation and stemness-associated features including CD34 and CD133 expression, side population and ALDH1 activity were detected by flow cytometry or immunoblotting. Expression profiles of these resistant cells were characterized by RNA sequencing. The susceptibility of resistant cells to different treatments was evaluated by in vitro CytoTox-glo assay and in tumor-bearing mice. The expression levels of SOX2, phos-AKT, CDK6 and FGFR1/2 were detected in 12 R-CHOP-resistant DLBCL clinical specimens by IHC. Results: The stem-like CSC proportion significantly increased in both resistant DLBCL subtypes. SOX2 expression level remarkably elevated in both resistant cell lines due to its phosphorylation by activated PI3K/AKT signaling, thus preventing ubiquitin-mediated degradation. Further, multiple factors, including BCR, integrins, chemokines and FGFR1/2 signaling, regulated PI3K/AKT activation. CDK6 in GCB subtype and FGFR1/2 in ABC subtype were SOX2 targets, whose inhibition potently re-sensitized resistant cells to R-CHOP treatment. More importantly, addition of PI3K inhibitor to R-CHOP completely suppressed the tumor growth of R-CHO-resistant DLBCL cells, most likely by converting CSCs to chemo-sensitive differentiated cells. Conclusions: The PI3K/AKT/SOX2 axis plays a critical role in R-CHOP resistance development and the pro-differentiation therapy against CSCs proposed in this study warrants further study in clinical trials for the treatment of resistant DLBCL.