Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, Chengdu, 610041, People's Republic of China,
Cancer Chemother Pharmacol. 2013 Nov;72(5):1001-11. doi: 10.1007/s00280-013-2285-8. Epub 2013 Sep 14.
Paclitaxel resistance remains to be a major obstacle to the chemotherapy of endometrial cancer. Using proteomic-based approach, we used to identify cyclophilin A (CypA) as a potential therapeutic target for endometrial cancer. As a natural continuation, this study aimed to reveal the correlation between CypA and paclitaxel resistance and evaluate the possibility of CypA as a therapeutic target for reversal of resistance.
Two paclitaxel-resistant endometrial cancer cell sublines HEC-1-B/TAX and AN3CA/TAX were generated, and expressions of CypA, P-gp, MRP-2 and survivin were demonstrated by Western blotting. CypA was knocked down by RNA interference, and the subsequent effects on the alteration of paclitaxel resistance were examined by MTT, flow cytometry and migratory/invasive transwell assays. MAPK kinases activities were examined by Western blotting.
CypA knockdown led to significant inhibition of cell proliferation, induction of apoptosis and suppression of migratory/invasive capacity in HEC-1-B/TAX and AN3CA/TAX cells when exposed to paclitaxel. CypA knockdown led to reductions in total and phosphorylated MAPK kinases, including Akt, ERK1/2, p38 MAPK and JNK, in HEC-1-B/TAX cells. Furthermore, pretreatment with MAPK kinase inhibitors exhibited a synergistic effect in combination with CypA knockdown.
These results demonstrated that CypA expression was up-regulated in paclitaxel-resistant cancer cells, and knockdown of CypA could reverse the paclitaxel resistance through, at least partly, suppression of MAPK kinase pathways, presenting a possibility of CypA serving as a therapeutic target to overcome paclitaxel resistance.
紫杉醇耐药仍是子宫内膜癌化疗的主要障碍。本研究采用基于蛋白质组学的方法，发现亲环素 A（CypA）可能成为子宫内膜癌的治疗靶点。在此基础上，本研究旨在揭示 CypA 与紫杉醇耐药的相关性，并评估 CypA 作为逆转耐药的治疗靶点的可能性。
构建了两种紫杉醇耐药的子宫内膜癌细胞系 HEC-1-B/TAX 和 AN3CA/TAX，通过 Western blot 检测 CypA、P-糖蛋白（P-gp）、多药耐药相关蛋白 2（MRP-2）和生存素的表达。采用 RNA 干扰技术敲低 CypA，通过 MTT、流式细胞术和迁移/侵袭 Transwell 实验检测 CypA 敲低对紫杉醇耐药性改变的影响，Western blot 检测丝裂原活化蛋白激酶激酶（MAPK kinase）的活性。
在紫杉醇作用下，HEC-1-B/TAX 和 AN3CA/TAX 细胞中 CypA 敲低导致细胞增殖显著抑制、凋亡诱导和迁移/侵袭能力下降。CypA 敲低导致 HEC-1-B/TAX 细胞中总 MAPK 激酶和磷酸化 MAPK 激酶（包括 Akt、细胞外信号调节激酶 1/2（ERK1/2）、p38 MAPK 和 c-Jun N-末端激酶（JNK））的活性降低。此外，MAPK 激酶抑制剂预处理与 CypA 敲低联合具有协同作用。
这些结果表明，紫杉醇耐药癌细胞中 CypA 表达上调，CypA 敲低通过抑制 MAPK 激酶通路至少部分逆转紫杉醇耐药，提示 CypA 可能成为克服紫杉醇耐药的治疗靶点。
