Mahmud Hasan, Scherpen Frank J G, de Boer Tiny Meeuwsen, Lourens Harm-Jan, Schoenherr Caroline, Eder Matthias, Scherr Michaela, Guryev Victor, De Bont Eveline S
Department of Pediatric Oncology/Hematology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
Oncotarget. 2017 Jun 27;8(40):67344-67354. doi: 10.18632/oncotarget.18631. eCollection 2017 Sep 15.
The t(8;21) (q22;q22) chromosomal translocation is one of the most frequent genetic alterations in acute myeloid leukemia (AML) which has a need for improved therapeutic strategies. We found PLC-γ1 as one of the highest phosphorylated peptides in t(8;21) AML samples compared to NBM or CN-AML in our previous peptide microarray. PLC-γ1 is known to play a role in cancer progression, however, the impact of PLC-γ1 in AML is currently unknown. Therefore, we aimed to study the functional role of PLC-γ1 by investigating the cellular growth, survival and its underlying mechanism in t(8;21) AML. In this study, PLC-γ1 expression was significantly higher in t(8;21) AML compared to other karyotypes. The PLC-γ1 protein expression was suppressed in AML1-ETO knock down cells indicating that it might induce kasumi-1 cell death. ShRNA-mediated PLC-γ1 knockdown in kasumi-1 cells significantly blocked cell growth, induced apoptosis and cell cycle arrest which was explained by the increased activation of apoptotic related and cell cycle regulatory protein expressions. Gene expression array analysis showed the up-regulation of apoptotic and DNA damage response genes together with the downregulation of cell growth, proliferation and differentiation genes in the PLC-γ1 suppressed kasumi-1 cells, consistent with the observed phenotypic effects. Importantly, PLC-γ1 suppressed kasumi-1 cells showed higher chemosensitivity to the chemotherapeutic drug treatments and lower cell proliferation upon hypoxic stress. Taken together, these finding strongly support an important role for PLC-γ1 in the survival of t(8;21) AML mimicking kasumi-1 cells and identify PLC-γ1 as a potential therapeutic target for t(8;21) AML treatment.
t(8;21)(q22;q22)染色体易位是急性髓系白血病（AML）中最常见的基因改变之一，因此需要改进治疗策略。在我们之前的肽微阵列研究中，我们发现与正常骨髓（NBM）或核型正常的AML（CN-AML）相比，PLC-γ1是t(8;21) AML样本中磷酸化程度最高的肽段之一。已知PLC-γ1在癌症进展中起作用，然而，PLC-γ1在AML中的影响目前尚不清楚。因此，我们旨在通过研究t(8;21) AML中的细胞生长、存活及其潜在机制来探讨PLC-γ1的功能作用。在本研究中，与其他核型相比，t(8;21) AML中PLC-γ1的表达明显更高。在AML1-ETO敲低的细胞中，PLC-γ1蛋白表达受到抑制，这表明它可能诱导kasumi-1细胞死亡。在kasumi-1细胞中，shRNA介导的PLC-γ1敲低显著阻断了细胞生长，诱导了细胞凋亡和细胞周期停滞，这可以通过凋亡相关蛋白和细胞周期调节蛋白表达的激活增加来解释。基因表达阵列分析显示，在PLC-γ1抑制的kasumi-1细胞中，凋亡和DNA损伤反应基因上调，同时细胞生长、增殖和分化基因下调，这与观察到的表型效应一致。重要的是，PLC-γ1抑制的kasumi-1细胞对化疗药物治疗表现出更高的化学敏感性，并且在低氧应激下细胞增殖更低。综上所述，这些发现有力地支持了PLC-γ1在模拟kasumi-1细胞的t(8;21) AML存活中起重要作用，并将PLC-γ1鉴定为t(8;21) AML治疗的潜在治疗靶点。
