Gefitinib is known as epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) while an increasing number of patients with non-small cell lung cancer (NSCLC) are becoming resistant to EGFR-TKI. Therefore, innovative methods are urgently needed to overcome primary and acquired resistance to EGFR-TKIs in NSCLC patients. The viability of HCC827 cells and HCC827 Ge-resistant (Ge-r) cells treated with gefitinib and/or STAT3 inhibitor and/or Overexpression (Oe)-ROR1 was detected by CCK-8 assay. The colony formation, invasion, migration and apoptosis of HCC827 Ge-r cells treated with gefitinib and/or STAT3 inhibitor and/or Oe-ROR1 transfection were, respectively, detected by clone formation assay, transwell assay, wound healing assay and flow cytometry analysis. The protein expressions of EGFR, STAT3, invasion and migration-related proteins, ROR1/ABCB1/P53 pathway and apoptosis-related proteins were analyzed by Western blot analysis. The transfection effect of Oe-ROR1 in HCC827 Ge-r cells was confirmed by qRT-PCR and Western blot analysis. In vivo animal experiment was used to confirm the role of STAT3 in improving the sensitivity of HCC827 Ge-r cells to gefitinib. As a result, after treatment of gefitinib, the viability of HCC827 cells was lower than that of HCC827 Ge-r cells and the expression of p/t-EGFR and p/t-STAT3 was decreased in HCC827 cells and HCC827 Ge-r cells after treatment of gefitinib. STAT3 inhibitor BBI608 enhanced the ability of gefitinib to inhibit viability, invasion and migration while promoting apoptosis of HCC827 Ge-r cells treated with gefitinib, which was partially reversed by ROR1 overexpression. STAT3 inhibitor further down-regulated the expression of MMP2, MMP9, ROR1, ABCB1 and BCl2, while up-regulated the expression of p53, bax and cleaved caspase3 in HCC827 Ge-r cells treated with gefitinib, which was partially reversed by ROR1 overexpression. In vivo experiment, STAT3 inhibitor further suppressed the size of NSCLC tissues, and further down-regulated the expression of ROR1 and ABCB1 while up-regulated the expression of p53 in NSCLC tissues. In conclusion, STAT3 inhibitor enhanced the antitumor effect of gefitinib on EGFR-mutated NSCLC cells through regulating ROR1/ABCB1/P53 pathway.

吉非替尼被称为表皮生长因子受体酪氨酸激酶抑制剂 (EGFR-TKI)，而越来越多的非小细胞肺癌 (NSCLC) 患者对 EGFR-TKI 产生耐药性。因此，迫切需要创新的方法来克服 NSCLC 患者对 EGFR-TKI 的原发性和获得性耐药性。通过 CCK-8 测定法检测用吉非替尼和/或 STAT3 抑制剂和/或过表达 (Oe)-ROR1 处理的 HCC827 细胞和 HCC827 Ge 抗性 (Ge-r) 细胞的活力。分别通过克隆形成试验、transwell试验、伤口愈合试验和流式细胞仪分析检测吉非替尼和/或STAT3抑制剂和/或Oe-ROR1转染HCC827 Ge-r细胞的集落形成、侵袭、迁移和凋亡情况. EGFR、STAT3、侵袭迁移相关蛋白的蛋白表达，通过蛋白质印迹分析分析ROR1 / ABCB1 / P53途径和细胞凋亡相关蛋白。通过qRT-PCR和Western印迹分析证实了Oe-ROR1在HCC827 Ge-r细胞中的转染效果。通过体内动物实验证实了STAT3在提高HCC827 Ge-r细胞对吉非替尼敏感性方面的作用。结果，吉非替尼处理后，HCC827细胞的活力低于HCC827 Ge-r细胞，p/t-EGFR和p/t-STAT3在HCC827细胞和HCC827 Ge-r细胞中的表达降低吉非替尼治疗后。STAT3 抑制剂 BBI608 增强了吉非替尼抑制活力、侵袭和迁移的能力，同时促进了吉非替尼处理的 HCC827 Ge-r 细胞的凋亡，这被 ROR1 过表达部分逆转。STAT3 抑制剂进一步下调 MMP2 的表达，MMP9、ROR1、ABCB1 和 BCl2，同时在用吉非替尼处理的 HCC827 Ge-r 细胞中上调 p53、bax 和切割的 caspase3 的表达，这被 ROR1 过表达部分逆转。在体内实验中，STAT3抑制剂进一步抑制了NSCLC组织的大小，进一步下调了NSCLC组织中ROR1和ABCB1的表达，同时上调了p53的表达。综上所述，STAT3抑制剂通过调节ROR1/ABCB1/P53通路增强了吉非替尼对EGFR突变NSCLC细胞的抗肿瘤作用。并进一步下调 NSCLC 组织中 ROR1 和 ABCB1 的表达，同时上调 p53 的表达。综上所述，STAT3抑制剂通过调节ROR1/ABCB1/P53通路增强了吉非替尼对EGFR突变NSCLC细胞的抗肿瘤作用。并进一步下调 NSCLC 组织中 ROR1 和 ABCB1 的表达，同时上调 p53 的表达。综上所述，STAT3抑制剂通过调节ROR1/ABCB1/P53通路增强了吉非替尼对EGFR突变NSCLC细胞的抗肿瘤作用。