Erdemir Feyzanur, Balcioglu Bertan Koray, Ozal Ildeniz Tugba Arzu, Can Ozge
Department of Biomedical Engineering, Institute of Natural Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Türkiye.
Medical Biotechnology Unit, Life Sciences, TUBITAK Marmara Research Center, Gebze 41470, Türkiye.
Int J Mol Sci. 2025 Apr 11;26(8):3594. doi: 10.3390/ijms26083594.
The EGFR pathway is activated by ligand binding, and EGFR overexpression is linked to malignancies like colorectal and head and neck cancer. This pathway is targeted by monoclonal antibodies such as Cetuximab; however, drug resistance can arise, frequently because of EGFR gene alterations like mutation, particularly in domain III, which inhibits Cetuximab binding. EGFR and MEGFR (R497K mutated EGFR) plasmids were transfected into Chinese hamster ovary (CHO) cells, which do not express EGFR. Real-time PCR was performed using probes that were specifically developed for the R497K mutation. Furthermore, Cetuximab binding to EGFR and MEGFR was examined using molecular modeling. According to molecular modeling, the R497K mutation modifies the domain III structure, which lowers the binding affinity of Cetuximab. Curiously, Cetuximab also showed binding to MEGFR's domain IV. Real-time PCR showed that the probes specifically identified MEGFR in transfected CHO cells. The R497K mutation may result in treatment resistance by decreasing Cetuximab binding or increasing competitive ligand binding. Therefore, for individualized treatment, it is essential to find EGFR mutations in patient tumor samples. The R497K mutation may be successfully detected by the designed oligonucleotide probes, allowing for the early identification of potential resistance and directing the development of suitable treatment strategies.
表皮生长因子受体（EGFR）通路通过配体结合被激活，EGFR的过表达与结直肠癌和头颈癌等恶性肿瘤有关。该通路是西妥昔单抗等单克隆抗体的作用靶点；然而，耐药性可能会出现，通常是由于EGFR基因改变，如突变，特别是在结构域III，这会抑制西妥昔单抗的结合。将EGFR和MEGFR（R497K突变的EGFR）质粒转染到不表达EGFR的中国仓鼠卵巢（CHO）细胞中。使用专门针对R497K突变开发的探针进行实时聚合酶链反应（PCR）。此外，使用分子建模研究了西妥昔单抗与EGFR和MEGFR的结合情况。根据分子建模，R497K突变改变了结构域III的结构，这降低了西妥昔单抗的结合亲和力。奇怪的是，西妥昔单抗也显示出与MEGFR的结构域IV结合。实时PCR表明，这些探针在转染的CHO细胞中特异性识别了MEGFR。R497K突变可能通过降低西妥昔单抗结合或增加竞争性配体结合导致治疗耐药性。因此，对于个体化治疗，在患者肿瘤样本中发现EGFR突变至关重要。设计的寡核苷酸探针可能成功检测到R497K突变，从而能够早期识别潜在的耐药性并指导制定合适的治疗策略。
