Choi Yun Jung, Park Gun Min, Rho Jin Kyung, Kim Sun Ye, So Gwang Sup, Kim Hyeong Ryul, Choi Chang-Min, Lee Jae Cheol
Department of Pulmonary and Critical Care Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea.
PLoS One. 2013 Dec 5;8(12):e81393. doi: 10.1371/journal.pone.0081393. eCollection 2013.
Most patients treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) eventually develop acquired resistance. Loss of expression of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) has been suggested as a possible mechanism of resistance to EGFR-TKIs in the A431 and HN11 cell lines. Here, we investigated IGFBP-3 expression in two EGFR mutant lung cancer cell lines with resistance to EGFR-TKIs and examined the value of serum IGFBP-3 level as a marker of resistance. The effect of the induction or suppression of IGFBP-3 expression on resistance was also evaluated. HCC827 sublines with resistance to gefitinib (HCC827/GR) and erlotinib (HCC827/ER) were established. Loss of IGFBP-3 expression was detected by Western blotting in both cell lines without changes in transcriptional activity, and ELISA showed significantly lower amounts of secreted IGFBP-3 in the culture media of the mutant cell lines than in that of the parental line. Despite the loss of IGFBP-3 expression, IGFR signalling activity remained unchanged. Forced expression of IGFBP-3 by adenovirus-mediated transfection or recombinant IGFBP-3 slightly increased the growth-inhibitory and apoptotic effects of EGFR-TKIs, whereas suppression of IGFBP-3 did not affect sensitivity to EGFR-TKI. Serum IGFBP-3 levels measured by ELISA before and after the development of EGFR-TKI resistance in 20 patients showed no significant changes (1815.3±94.6 ng/mL before treatment vs. 1778.9±87.8 ng/mL after EGFR-TKI resistance). In summary, although IGFBP-3 downregulation is associated with the acquisition of resistance to EGFR-TKIs regardless of the mechanism, its effect on resistance was not significant, indicating that IGFBP-3 may not play an important role in resistance to EGFR-TKIs and serum IGFBP-3 level is not a reliable indicator of resistance.
大多数接受表皮生长因子受体酪氨酸激酶抑制剂（EGFR-TKIs）治疗的患者最终会产生获得性耐药。胰岛素样生长因子（IGF）结合蛋白-3（IGFBP-3）表达缺失被认为是A431和HN11细胞系中对EGFR-TKIs产生耐药的一种可能机制。在此，我们研究了两种对EGFR-TKIs耐药的EGFR突变肺癌细胞系中IGFBP-3的表达情况，并检测了血清IGFBP-3水平作为耐药标志物的价值。我们还评估了IGFBP-3表达的诱导或抑制对耐药性的影响。建立了对吉非替尼（HCC827/GR）和厄洛替尼（HCC827/ER）耐药的HCC827亚系。通过蛋白质免疫印迹法在两种细胞系中均检测到IGFBP-3表达缺失，且转录活性无变化，酶联免疫吸附测定（ELISA）显示突变细胞系培养基中分泌的IGFBP-3量显著低于亲代细胞系。尽管IGFBP-3表达缺失，但IGFR信号活性保持不变。通过腺病毒介导的转染或重组IGFBP-3强制表达IGFBP-3，可略微增强EGFR-TKIs的生长抑制和凋亡作用，而抑制IGFBP-3并不影响对EGFR-TKI的敏感性。对20例患者在出现EGFR-TKI耐药前后通过ELISA测定的血清IGFBP-3水平无显著变化（治疗前为1815.3±94.6 ng/mL，EGFR-TKI耐药后为1778.9±87.8 ng/mL）。总之，尽管无论机制如何，IGFBP-3下调均与对EGFR-TKIs获得性耐药相关，但其对耐药性的影响并不显著，这表明IGFBP-3可能在对EGFR-TKIs的耐药中不发挥重要作用，且血清IGFBP-3水平不是耐药的可靠指标。
