Xu Yefang, Zhang Jingjing, Wu Jing, Zhong Sheng, Li Hongxia
*Department of Obstetrics and Gynecology, Beijing Shijitan Hospital, Capital Medical University, Haidian District, Beijing, China; †Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN; and ‡Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China.
Int J Gynecol Cancer. 2015 Nov;25(9):1557-64. doi: 10.1097/IGC.0000000000000550.
Resistance to chemotherapy is a major factor that limits the postsurgical survival of ovarian cancer patients. Janus-activated kinase 2 (JAK2) has been implicated in cancer cell survival and the development of drug resistance in ovarian cancers. In the present study, we sought to determine whether inhibition of JAK2 reverses drug resistance in OC3/TAX300 cells, a paclitaxel-resistant human ovarian cancer cell line previously established in our laboratory.
OC3/TAX300 cells were transduced with lentivirus expressing small interference RNA (siRNA) against JAK2 and treated with JAK2 kinase inhibitor AG490.
Treatment with JAK2-siRNA markedly decreased the messenger RNA and protein of JAK2 as determined by real-time polymerase chain reaction and Western blot analysis. OC3/TAX300 cells treated with JAK2-siRNA exhibited stalled growth, increased cell cycle arrest in G2/M phase, and enhanced apoptosis in response to paclitaxel. In keeping with this, JAK2-siRNA also inhibited the expression of multidrug resistance protein 1. To determine whether JAK2 promotes paclitaxel resistance via phosphorylation of signal transducer and activator of transcription 3 (STAT3), a transcription factor known to be involved in resistance to chemotherapy, we treated OC3/TAX300 cells with JAK2 kinase inhibitor AG490. Of note, AG490 reduced the level of p-STAT3 and inhibited the expression of multidrug resistance protein 1 in a dose-dependent manner.
Collectively, we conclude that the JAK2-STAT3 pathway promotes the development of paclitaxel resistance via upregulating the expression of prosurvival and antiapoptotic genes. Targeting this pathway may be effective in reversing resistance to chemotherapy in ovarian cancers.
化疗耐药是限制卵巢癌患者术后生存的主要因素。Janus激活激酶2（JAK2）与癌细胞存活及卵巢癌耐药性的发展有关。在本研究中，我们试图确定抑制JAK2是否能逆转OC3/TAX300细胞的耐药性，OC3/TAX300细胞是我们实验室先前建立的一种耐紫杉醇的人卵巢癌细胞系。
用表达针对JAK2的小干扰RNA（siRNA）的慢病毒转导OC3/TAX300细胞，并用JAK2激酶抑制剂AG490处理。
通过实时聚合酶链反应和蛋白质印迹分析确定，用JAK2-siRNA处理可显著降低JAK2的信使核糖核酸和蛋白质水平。用JAK2-siRNA处理的OC3/TAX300细胞生长停滞，G2/M期细胞周期阻滞增加，对紫杉醇的凋亡增强。与此一致的是，JAK2-siRNA也抑制多药耐药蛋白1的表达。为了确定JAK2是否通过磷酸化信号转导和转录激活因子3（STAT3）促进紫杉醇耐药，STAT3是一种已知参与化疗耐药的转录因子，我们用JAK2激酶抑制剂AG490处理OC3/TAX300细胞。值得注意的是，AG490以剂量依赖的方式降低了p-STAT3的水平并抑制了多药耐药蛋白1的表达。
总体而言，我们得出结论，JAK2-STAT3通路通过上调生存和抗凋亡基因的表达促进紫杉醇耐药的发展。靶向该通路可能有效逆转卵巢癌的化疗耐药。
