Abstract：
OBJECTIVE: YAP1 plays a dual role as an oncogene and tumor suppressor gene in several tumors; differentiating between these roles may depend on the YAP1 phosphorylation pattern. The specific function of YAP1 in B cell acute lymphoblastic leukemia (B-ALL), however, is currently unclear. Thus, in the present study, the role of YAP1 in B-ALL was investigated using relevant cell lines and patient datasets.
METHODS: The effects of shRNA-mediated knockdown on YAP1 and LATS1 levels in the NALM6 and MOLT-4 cell lines were examined using Western blotting, quantitative real-time polymerase chain reaction, flow cytometry, immunostaining, and nude mouse subcutaneous tumorigenesis experiments. Gene expression levels of Hippo pathway-related molecules before and after verteporfin (VP) treatment were compared using RNA-Seq to identify significant Hippo pathway-related genes in NALM6 cells.
RESULTS: Patients with ALL showing high YAP1 expression and low YAP1-Ser127 phosphorylation levels had worse prognoses than those with low YAP1 protein expression and high YAP1-Ser127 phosphorylation levels. YAP1-Ser127 phosphorylation levels were lower in NALM6 cells than in MOLT-4 and control cells; YAP1 was distributed in the nuclei in NALM6 cells. Knockdown of YAP1 inhibited MOLT-4 and NALM6 cell proliferation and arrested the NALM6 cell cycle in the G0/G1 phase. Before and after VP treatment, the expression of the upstream gene LATS1 was upregulated; its overexpression promoted YAP1-Ser127 phosphorylation. Further, YAP1 was distributed in the plasma.
CONCLUSIONS: LATS1 may downregulate YAP1-Ser127 phosphorylation and maintain B-ALL cell function; thus, VP, which targets this axis, may serve as a new therapeutic method for improving the outcomes for B-ALL patients.
METHODS: The effects of shRNA-mediated knockdown on YAP1 and LATS1 levels in the NALM6 and MOLT-4 cell lines were examined using Western blotting, quantitative real-time polymerase chain reaction, flow cytometry, immunostaining, and nude mouse subcutaneous tumorigenesis experiments. Gene expression levels of Hippo pathway-related molecules before and after verteporfin (VP) treatment were compared using RNA-Seq to identify significant Hippo pathway-related genes in NALM6 cells.
RESULTS: Patients with ALL showing high YAP1 expression and low YAP1-Ser127 phosphorylation levels had worse prognoses than those with low YAP1 protein expression and high YAP1-Ser127 phosphorylation levels. YAP1-Ser127 phosphorylation levels were lower in NALM6 cells than in MOLT-4 and control cells; YAP1 was distributed in the nuclei in NALM6 cells. Knockdown of YAP1 inhibited MOLT-4 and NALM6 cell proliferation and arrested the NALM6 cell cycle in the G0/G1 phase. Before and after VP treatment, the expression of the upstream gene LATS1 was upregulated; its overexpression promoted YAP1-Ser127 phosphorylation. Further, YAP1 was distributed in the plasma.
CONCLUSIONS: LATS1 may downregulate YAP1-Ser127 phosphorylation and maintain B-ALL cell function; thus, VP, which targets this axis, may serve as a new therapeutic method for improving the outcomes for B-ALL patients.
摘要：
目的：YAP1作为癌基因和抑癌基因在多种肿瘤中发挥双重作用；区分这些作用可能取决于YAP1的磷酸化模式。YAP1在B细胞急性淋巴细胞白血病（B-ALL）中的特定功能，然而,目前尚不清楚。因此，在本研究中，我们使用相关细胞系和患者数据集研究了YAP1在B-ALL中的作用.
方法：使用蛋白质印迹检查shRNA介导的敲低对NALM6和MOLT-4细胞系中YAP1和LATS1水平的影响，定量实时聚合酶链反应，流式细胞术,免疫染色，和裸鼠皮下肿瘤发生实验。使用RNA-Seq比较维替泊芬（VP）治疗前后Hippo途径相关分子的基因表达水平，以鉴定NALM6细胞中重要的Hippo途径相关基因。
结果：显示高YAP1表达和低YAP1-Ser127磷酸化水平的ALL患者的预后比那些低YAP1蛋白表达和高YAP1-Ser127磷酸化水平的患者差。NALM6细胞中YAP1-Ser127磷酸化水平低于MOLT-4和对照细胞；YAP1在NALM6细胞中分布在细胞核中。敲除YAP1抑制MOLT-4和NALM6细胞增殖，并将NALM6细胞周期阻滞在G0/G1期。VP治疗前后,上游基因LATS1的表达上调；其过表达促进YAP1-Ser127磷酸化。Further,YAP1在血浆中分布。
结论：LATS1可能下调YAP1-Ser127磷酸化并维持B-ALL细胞功能；VP,瞄准这个轴，可能作为改善B-ALL患者预后的新治疗方法。
方法：使用蛋白质印迹检查shRNA介导的敲低对NALM6和MOLT-4细胞系中YAP1和LATS1水平的影响，定量实时聚合酶链反应，流式细胞术,免疫染色，和裸鼠皮下肿瘤发生实验。使用RNA-Seq比较维替泊芬（VP）治疗前后Hippo途径相关分子的基因表达水平，以鉴定NALM6细胞中重要的Hippo途径相关基因。
结果：显示高YAP1表达和低YAP1-Ser127磷酸化水平的ALL患者的预后比那些低YAP1蛋白表达和高YAP1-Ser127磷酸化水平的患者差。NALM6细胞中YAP1-Ser127磷酸化水平低于MOLT-4和对照细胞；YAP1在NALM6细胞中分布在细胞核中。敲除YAP1抑制MOLT-4和NALM6细胞增殖，并将NALM6细胞周期阻滞在G0/G1期。VP治疗前后,上游基因LATS1的表达上调；其过表达促进YAP1-Ser127磷酸化。Further,YAP1在血浆中分布。
结论：LATS1可能下调YAP1-Ser127磷酸化并维持B-ALL细胞功能；VP,瞄准这个轴，可能作为改善B-ALL患者预后的新治疗方法。
