Shen Shen, Dean Dylan C, Yu Zujiang, Hornicek Francis, Kan Quancheng, Duan Zhenfeng
Precision Medicine Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China.
Sarcoma Biology Laboratory, Department of Orthopaedic Surgery, David Geffen School of Medicine at University of Los Angeles, Los Angeles, CA 90095, USA.
J Cancer. 2020 Jan 1;11(1):132-141. doi: 10.7150/jca.35426. eCollection 2020.
Chordomas are slow-growing malignancies that commonly affect vital neurological structures. These neoplasms are highly resistant to current chemotherapeutic regimens and often recur after surgical intervention. Therefore, there is an urgent need to identify molecular targets and more robust drugs to improve chordoma patient outcomes. It is well accepted that cyclin-dependent protein kinase 9 (CDK9) has tumorigenic roles in various cancers; however, the expression and significance of CDK9 in chordoma remains unknown. Methods: Expression of CDK9 in chordoma cell lines and tumor tissues was examined by Western blot and immunohistochemistry (IHC). The correlation between CDK9 expression in patient tissues and clinical prognosis was analyzed. The functional roles of CDK9 in chordoma were investigated after the addition of small interfering RNA (siRNA) and CDK9 inhibitor (LDC000067). Cell growth and proliferation were assessed with MTT and clonogenic assays. The effect of CDK9 inhibition on chordoma cells was further evaluated with a three-dimensional (3D) cell culture model which mimics the environment. CDK9 was expressed in both chordoma cell lines and chordoma tissues. High- expression of CDK9 correlated with recurrence and poor outcomes for chordoma patients. CDK9 silencing with siRNA decreased growth and proliferation of chordoma cells and lowered levels of Mcl-1 and RNA polymerase II (RNAP II) phosphorylation. Pharmacological inhibition of CDK9 with the small molecular inhibitor LDC000067 reduced cell growth, supported apoptosis, suppressed cell colony formation in a clonogenic assay, and decreased spheroid growth in 3D culture. We demonstrate that CDK9 expression in chordoma correlates with patient outcome, and, when inhibited, chordoma cell growth and proliferation significantly decreases. Taken together, these results support CDK9 as an emerging potential target in chordoma therapy.
脊索瘤是生长缓慢的恶性肿瘤，通常会影响重要的神经结构。这些肿瘤对当前的化疗方案具有高度抗性，并且在手术干预后常常复发。因此，迫切需要确定分子靶点和更有效的药物，以改善脊索瘤患者的治疗结果。众所周知，细胞周期蛋白依赖性蛋白激酶9（CDK9）在各种癌症中具有致瘤作用；然而，CDK9在脊索瘤中的表达及意义尚不清楚。方法：通过蛋白质免疫印迹法和免疫组织化学（IHC）检测CDK9在脊索瘤细胞系和肿瘤组织中的表达。分析患者组织中CDK9表达与临床预后的相关性。在添加小分子干扰RNA（siRNA）和CDK9抑制剂（LDC000067）后，研究CDK9在脊索瘤中的功能作用。用MTT法和克隆形成试验评估细胞生长和增殖。用模拟环境的三维（3D）细胞培养模型进一步评估CDK9抑制对脊索瘤细胞的影响。CDK9在脊索瘤细胞系和脊索瘤组织中均有表达。CDK9的高表达与脊索瘤患者的复发和不良预后相关。用siRNA沉默CDK9可降低脊索瘤细胞的生长和增殖，并降低Mcl-1和RNA聚合酶II（RNAP II）磷酸化水平。用小分子抑制剂LDC000067对CDK9进行药理抑制可减少细胞生长，促进凋亡，在克隆形成试验中抑制细胞集落形成，并减少3D培养中的球体生长。我们证明，脊索瘤中CDK9的表达与患者预后相关，并且当CDK9被抑制时，脊索瘤细胞的生长和增殖显著降低。综上所述，这些结果支持CDK9作为脊索瘤治疗中一个新出现的潜在靶点。
