AQP5 silencing suppresses p38 MAPK signaling and improves drug resistance in colon cancer cells
AQP5 silencing suppresses p38 MAPK signaling and improves drug resistance in colon cancer cells
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DOI：
10.1007/s13277-014-1956-3
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发表时间：
2014-07-01
期刊：
影响因子：
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通讯作者：
Zhao, Wei
中科院分区：
文献类型：
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作者：
Shi, Xiaoming;Wu, Shengchun;Zhao, Wei
水通道蛋白5(AQP5)可能是治疗结肠癌(CC)的新靶点，但AQP5在结肠癌多药耐药(MDR)调控中的作用尚不清楚。本研究检测癌组织及癌旁组织中AQP5、P-糖蛋白(P-gp)、谷胱甘肽S转移酶(GST-PI)、拓扑异构酶II(TOPO II)和胸苷合成酶(TS)的表达；应用AQP5-siRNA沉默癌细胞株HT-29中的AQP5，应用5-氟尿嘧啶(5-FU)和细胞上加顺铂(DDP)，并应用磺胺类药物B(SRB)；采用实时荧光定量RT-PCR和Western印迹方法检测多药耐药因子的变化和丝裂原激活蛋白激酶(MAPK)信号通路的表达。结果表明，AQP5在癌组织中的表达明显高于癌旁组织。癌组织中P-gp、GST-pi和Topo II的表达高于癌旁组织，表明AQP5的表达与耐药因素呈正相关。相反，在HT-29人结肠癌细胞中敲除AQP5会增加5-FU和DDP等癌症化疗药物的抑制率。化疗药物疗效的提高与P-gp、GST-pi和Topo II的表达降低有关。此外，AQP5基因敲除后，p38MAPK的磷酸化增加，而细胞外信号调节激酶(ERK)、c-jun氨基末端激酶(JNK)和蛋白激酶B(AKT)的磷酸化和表达不受影响。与AQP5-siRNAs类似，p38MAPK抑制剂增加了HT-29细胞对药物的敏感性。这些结果表明，AQP5与结肠癌耐药有关，AQP5-P38MAPK通路可能是改善结肠癌耐药的潜在药物靶点。
It is known that aquaporin 5 (AQP5) may represent a novel therapeutic target for treating colon cancer (CC), but whether AQP5 plays a role in the regulation of multidrug resistance (MDR) of colon cancer still remains unclear. In the present study, AQP5 and P-glycoprotein (P-gp), glutathione S-transferase-pi (GST-pi), topoisomerase II (TOPO II), and thymidylate synthase (TS) were checked in CC and adjacent cancer tissues; AQP5-siRNA was applied to silencing AQP5 in CC cell line HT-29, 5-fluorouracil (5-FU), and cisplatin (DDP) added on cells, and sulforhodamine B (SRB) was used; fluorescence real-time quantitative RT-PCR and Western blot were employed to detect changes in multidrug resistance factor and expression mitogen-activated protein kinase (MAPK) signaling pathway in HT-29. The results showed that AQP5 is significantly induced in cancer tissues than that in adjacent cancer tissues. The expression of AQP5 is positively correlated with drug resistance factors, as demonstrated by the increased expressions of P-gp, GST-pi, and TOPO II in CC tissues compared to that in adjacent cancer tissues. Conversely, knockdown of AQP5 in HT-29 human colon cancer cells increased inhibition rates of cancer chemotherapeutic drugs such as 5-FU and DDP. The improved efficacies of chemotherapeutic drugs are associated with the decreased expression of P-gp, GST-pi, and TOPO II. In addition, phosphorylation of p38 MAPK was increased by knockdown of AQP5 in HT-29 cells while phosphorylation and expression of extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and Protein kinase B (AKT) were not affected. P38 MAPK inhibitor increased the drug sensitivity of HT-29 cells in a similar way as AQP5-siRNAs do. So these results indicate that AQP5 is associated with drug resistance of colon cancer, and that the AQP5-P38 MAPK pathway may represent a potential drug target to improve drug resistance of colon cancer cells.