靶向细胞周期蛋白依赖性激酶11通路对骨肉瘤细胞的作用

Standard treatment for osteosarcoma is surgery and chemotherapy. Chemotherapy has significantly improved the survival rate from 10% with surgery alone to > 60% when surgery is combined with chemotherapy. Unfortunately, for the 20-40% who are not cured with surgery and chemotherapy, prognosis is poor and treatment options are very limited. Thus, identification of new targeted therapies is critical to improving the survival rate of osteosarcoma patients. There are now numerous examples linking dysregulated activation and expression of kinases to cancer, and inhibiting kinases in tumor cells has become a promising therapeutic strategy. Indeed, several kinase-targeted therapies have revolutionized the treatment of several types of cancer. Recently, we and others have demonstrated consistent results of knockdown the kinase CDK11 (cyclin-dependent kinase 11, also known as CDC2L for cell division cycle 2-like or PITSLRE) by shRNA or siRNA inhibit tumor cell growth and induce apoptosis. Importantly, nuclear CDK11 expression levels correlates with clinical prognosis in osteosarcoma patients, and inhibition of CDK11 expression significantly suppressed tumor growth in vivo. We are interested in targeting CDK11 as a therapeutic strategy for patients with osteosarcoma. To the best of our knowledge, such a study has not yet been done. The aims of the study are to: (i) Dissect signaling network operated through CDK11 in osteosarcoma; (ii) Identify small molecule CDK11 kinase inhibitors against osteosarcoma cell proliferation; (iii) Evaluation of anti-tumor efficacy of CDK11 kinase-specific inhibitor in osteosarcoma xenograft mouse model. Our long term goals are to elucidate the regulatory mechanisms controlling expression of CDK11 and ultimately develop a CDK11 inhibitor that can be used to improve the treatment of patients with osteosarcoma. This approach will lead to a clinically translatable kinase CDK11 -based cancer therapy.

骨肉瘤的标准治疗方案包括手术治疗和化学治疗。但仍有20-40%的患者在接受手术和化学治疗后临床预后仍然较差。因此，寻找新的靶向治疗方案对于改善骨肉瘤患者的生存率很关键。目前有很多的关于激酶表达与肿瘤相关的研究，发现抑制激酶能够显著改善某些肿瘤的治疗。近几年，我们和其他研究人员通过激酶高通量筛选RNA干扰技术，发现细胞周期蛋白依赖性激酶11（CDK11）的表达对肿瘤的生长增殖起关键作用。CDK11的表达水平与骨肉瘤患者的临床预后显著相关，体内实验表明沉默CDK11能够显著抑制肿瘤的生长。本研究的目标是：（1）分析CDK11信号通路在骨肉瘤中的作用；（2）筛选鉴定能够抑制骨肉瘤细胞增殖的CDK11激酶小分子抑制剂；（3）评价CDK11激酶特异性抑制剂在骨肉瘤小鼠模型中的抗肿瘤作用。我们的长期目标是阐释CDK11表达的调控机制并最终研发CDK11的抑制剂，使其能够改善骨肉瘤及其他肿瘤的治疗。

骨肉瘤的标准治疗方案包括手术治疗和化学治疗，但仍有20-40%的患者在接受手术和化学治疗后临床预后仍然较差。寻找新的靶向治疗方案对于改善骨肉瘤患者的生存率很关键。目前有很多的关于激酶表达与肿瘤相关的研究，抑制激酶能够显著改善某些肿瘤的治疗。我们通过激酶高通量筛选RNA干扰，CRISPR-Cas9等技术，发现细胞周期蛋白依赖性激酶11（CDK11）的表达对肿瘤的生长增殖起关键作用。CDK11的表达水平与骨肉瘤患者的临床预后显著相关，体内实验表明沉默CDK11能够显著抑制肿瘤的生长。因此，我们申请国家自然科学基金面上项目，进一步分析CDK11信号通路在骨肉瘤中的作用，筛选鉴定能够抑制骨肉瘤细胞增殖的CDK11激酶小分子抑制剂，评价CDK11激酶特异性抑制剂在骨肉瘤小鼠模型中的抗肿瘤作用。旨在阐释CDK11表达的调控机制并最终研发CDK11的抑制剂，使其能够改善骨肉瘤及其他肿瘤的治疗。CDK11p110和CDK11p58异构体分别位于细胞核和细胞浆：CDK11 基因位于染色体 1p36.33，编码CDK11p110和CDK11p58两种异构体。我们研究了两种异构体的亚细胞定位。不同 CDK11 异构体基因分别于绿色荧光蛋GFP基因融合并克隆到真核表达载体，转染肿瘤细胞后，表达的CDK11p110蛋白主要位于细胞核内，而表达CDK11p58主要定位于细胞浆。此外，CDK11p110在多种肿瘤细胞中高表达。 CDK11p110蛋白也主要定位在肿瘤组织的细胞核。这些结果表明，肿瘤细胞的生长增殖依赖于CDK11p110异构体。筛选到潜在的CDK11小分子抑制剂： 我们筛选了一个含有500种激酶抑制剂的小分子化合物库，采用ATP/NADH耦合方法，我们已筛选到潜在的CDK11抑制化合物。进一步在骨肉瘤细胞中测试，包括JWD047等几个小分子化合物对CDK11有明显的特异性抑制作用。CDK11在卵巢癌细胞增殖与生长中的作用：另外，我们研究发现CDK11也是卵巢癌细胞存活的必要基因，CDK11在卵巢癌细胞的增殖、迁移，凋亡与细胞周期调节中发挥重要作用，提示CDK11可能作为卵巢癌治疗的一个潜在分子靶点。综上，我们对CDK11在肿瘤中的作用与机制研究取得重要成果，完成了既定目标。