Department of Gastroenterology, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China.
Department of Oncology, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China.
Mol Med Rep. 2018 May;17(5):7274-7280. doi: 10.3892/mmr.2018.8763. Epub 2018 Mar 16.
Pancreatic cancer (PC) is one of the most common types of malignant tumor and the leading cause of cancer‑associated mortality worldwide. The chemotherapeutic drug gemcitabine (GEM) is used as a first‑line chemotherapeutic agent for advanced PC. However, the acquisition of drug resistance is a major limitation of the clinical effect of GEM and commonly leads to increased metastasis. The occurrence of epithelial‑mesenchymal transition (EMT) has been demonstrated to be the underlying mechanism of acquired resistance. It has been reported that heat treatment is able to inhibit EMT in pancreatic adenocarcinoma cells. In the present study the effect of hyperthermia on the sensitivity of GEM‑resistant PC cells was investigated. First a GEM‑resistant PC cell line PANC‑1 (PAN/GEM) was developed and it was demonstrated that drug resistant PAN/GEM cells exhibited significantly increased migratory and invasive abilities compared with control PANC‑1 cells using a Transwell assay. EMT was induced in resistant PAN/GEM cells, followed by reduced epithelial marker epithelial (E)‑cadherin expression and increased mesenchymal marker Vimentin expression compared with control PANC‑1 cells. Next, the Transwell assay demonstrated that the hyperthermia at 42˚C for 1 h combined with GEM significantly attenuated migration and invasion in drug resistant PAN/GEM cells, while GEM alone treatment did not significantly affect the migration and invasion. Additionally, EMT in PAN/GEM cells was reversed by hyperthermia, as demonstrated by the restoration of E‑cadherin and downregulation of mesenchymal markers Vimentin, matrix metalloproteinase (MMP)2 and MMP9. Furthermore, an MMP2 inhibitor tissue inhibitor of metalloproteinases (TIMP)2 and MMP9 inhibitor TIMP1 were used to treat PAN/GEM cells and it was demonstrated that both inhibitors increased the inhibition of hyperthermia treatment combined with GEM on cell invasion, suggesting an association between cell invasion and MMP2, and MMP9. Additionally, proliferation of PAN/GEM cells following hyperthermia was assessed using an MTT assay. The results demonstrated that proliferation in PAN/GEM cells treated with hyperthermia was significantly inhibited by GEM compared with GEM alone treated cells, indicating that hyperthermia enhanced the inhibition of GEM on cell growth and resensitized the drug‑resistant cells to GEM. Overall, the results of the present study suggested that hyperthermia is able to resensitize GEM‑resistant PANC‑1 cells to GEM by reversing EMT via the regulation of EMT‑associated factors, therefore inhibiting cell migration and invasion.
胰腺癌（PC）是最常见的恶性肿瘤类型之一，也是全球癌症相关死亡的主要原因。化疗药物吉西他滨（GEM）被用作晚期 PC 的一线化疗药物。然而，获得耐药性是 GEM 临床疗效的主要限制因素，并且通常会导致转移增加。已经证明上皮-间充质转化（EMT）的发生是获得性耐药的潜在机制。据报道，热疗能够抑制胰腺腺癌细胞中的 EMT。在本研究中，研究了高温对 GEM 耐药 PC 细胞敏感性的影响。首先，开发了一种 GEM 耐药 PC 细胞系 PANC-1（PAN/GEM），并通过 Transwell 分析证明，与对照 PANC-1 细胞相比，耐药 PAN/GEM 细胞表现出明显增加的迁移和侵袭能力。在耐药 PAN/GEM 细胞中诱导 EMT，随后与对照 PANC-1 细胞相比，上皮标志物上皮（E）-钙粘蛋白的表达减少，间充质标志物波形蛋白的表达增加。接下来，Transwell 分析表明，在 42°C 下 1 小时的热疗与 GEM 联合显著减弱了耐药 PAN/GEM 细胞的迁移和侵袭，而 GEM 单独治疗对迁移和侵袭没有显著影响。此外，热疗逆转了 PAN/GEM 细胞中的 EMT，表现为 E-钙粘蛋白的恢复和间充质标志物波形蛋白、基质金属蛋白酶（MMP）2 和 MMP9 的下调。此外，还使用 MMP2 抑制剂金属蛋白酶组织抑制剂（TIMP）2 和 MMP9 抑制剂 TIMP1 治疗 PAN/GEM 细胞，结果表明两种抑制剂均增加了热疗联合 GEM 对细胞侵袭的抑制作用，提示细胞侵袭与 MMP2 和 MMP9 之间存在关联。此外，通过 MTT 分析评估了 PAN/GEM 细胞在高温后的增殖情况。结果表明，与单独用 GEM 处理的细胞相比，用热疗处理的 PAN/GEM 细胞中的增殖明显受到 GEM 的抑制，表明热疗增强了 GEM 对细胞生长的抑制作用，并使耐药细胞对 GEM 重新敏感。总体而言，本研究结果表明，热疗通过调节 EMT 相关因子使 GEM 耐药的 PANC-1 细胞 EMT 逆转，从而抑制细胞迁移和侵袭，使 GEM 耐药的 PANC-1 细胞对 GEM 重新敏感。
