Identification and validation of COX-2 as a co-target for overcoming cetuximab resistance in colorectal cancer cells.
Identification and validation of COX-2 as a co-target for overcoming cetuximab resistance in colorectal cancer cells.
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DOI：
10.18632/oncotarget.8649
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发表时间：
2016-10-04
期刊：
影响因子：
--
通讯作者：
Fan Z
中科院分区：
文献类型：
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作者：
Lu Y;Shi C;Qiu S;Fan Z
西妥昔单抗是一种表皮生长因子受体 (EGFR) 阻断抗体，十多年前被批准用于治疗转移性结直肠癌；然而，由于西妥昔单抗的内在耐药性和获得性耐药性，患者对西妥昔单抗的反应差异很大。在此，我们使用 Affymetrix HG-U133A 阵列报告我们的研究结果，以检查 DiFi（一种对西妥昔单抗高度敏感的人类结直肠癌细胞系）与其他两种细胞系之间的全局基因表达变化：DiFi5（一种对西妥昔单抗获得性耐药的 DiFi 亚系）和 DiFi-AG（一种对 EGFR 酪氨酸激酶抑制剂 AG1478 获得性耐药但对西妥昔单抗敏感的 DiFi 亚系）。我们发现前列腺素内过氧化物合酶 2 (PTGS2) 编码环氧合酶 2 (COX-2)，是西妥昔单抗耐药 DiFi5 细胞与西妥昔单抗敏感 DiFi 细胞和 DiFi-AG 细胞之间差异最大的基因。逆转录聚合酶链反应和蛋白质印迹验证了 DiFi5 中 COX-2 的上调，但在 DiFi 或 DiFi-AG 细胞中没有上调。我们从 DiFi5 细胞中开发了 COX-2 敲低的稳定克隆，并证明 COX-2 的基因敲低使 DiFi5 细胞对西妥昔单抗部分重新敏感。我们进一步证实，西妥昔单抗与 COX-2 抑制剂联合使用，不仅在 DiFi5 细胞中，而且在另一种对西妥昔单抗天然耐药的结直肠癌细胞系中，通过凋亡或自噬导致细胞死亡。我们的研究结果支持进一步评估西妥昔单抗和 COX-2 抑制剂联合治疗转移性结直肠癌的策略。
Cetuximab, an epidermal growth factor receptor (EGFR)-blocking antibody, was approved for treatment of metastatic colorectal cancer over a decade ago; however, patients' responses to cetuximab vary substantially due to intrinsic and acquired resistance to cetuximab. Here, we report our findings using Affymetrix HG-U133A array to examine changes in global gene expression between DiFi, a human colorectal cancer cell line that is highly sensitive to cetuximab, and two other cell lines: DiFi5, a DiFi subline with acquired resistance to cetuximab, and DiFi-AG, a DiFi subline with acquired resistance to the EGFR tyrosine kinase inhibitor AG1478 but sensitivity to cetuximab. We identified prostaglandin-endoperoxide synthase 2 (PTGS2), which encodes cyclooxygenase-2 (COX-2), as the gene with the greatest difference between the cetuximab-resistant DiFi5 cells and the cetuximab-sensitive DiFi cells and DiFi-AG cells. Reverse transcription polymerase chain reaction and Western blotting validated upregulation of COX-2 in DiFi5 but not in DiFi or DiFi-AG cells. We developed COX-2 knockdown stable clones from DiFi5 cells and demonstrated that genetic knockdown of COX-2 partially re-sensitized DiFi5 cells to cetuximab. We further confirmed that cetuximab in combination with a COX-2 inhibitor led to cell death via apoptosis or autophagy not only in DiFi5 cells but also in another colorectal cancer cell line naturally resistant to cetuximab. Our findings support further evaluation of the strategy of combining cetuximab and a COX-2 inhibitor for treatment of metastatic colorectal cancer.