EGFR-TARGETING GE11-DERIVED PEPTIDE DIFFERENTIALLY MODULATES TRIPLE-NEGATIVE BREAST CANCER AND GLIOBLASTOMA CELL PROLIFERATION IN VITRO

Introduction Triple-negative breast cancer (TNBC) represents one of the most aggressive subtypes of breast cancer. Glioblastoma (GBM) is the most lethal primary brain tumor, characterized by poor prognosis. Both malignancies frequently overexpress the epidermal growth factor receptor (EGFR), which contributes to tumor progression by promoting proliferation, angiogenesis, and resistance to apoptosis. The GE11 peptide, YHWYGYTPQNVI, exhibits high affinity for EGFR and has been explored as a targeting ligand in molecular imaging strategies. Here, a modified GE11-derived peptide, YHAYGYTPQNVI, was employed, in which tryptophan was substituted by alanine to reduce photosensitivity. Objectives To evaluate the in vitro effects of the YHAYGYTPQNVI peptide on cell proliferation and viability in TNBC (MDA-MB-231) and GBM (U-87 MG) cells. Materials and Methods MDA-MB-231 and U-87 MG cells were cultured in RPMI-1640 or DMEM, respectively, supplemented with 10% fetal bovine serum (37°C; 5% CO2). Cell proliferation was assessed by growth curve analysis. Cells were seeded in 6-well plates (5 × 104 cells/well) and treated with YHAYGYTPQNVI (56.1 µM). Viable cell counts were performed on days 1, 3, 5, and 7, comparing with untreated control (CT). Cell viability was evaluated by the MTT assay in MDA-MB-231 cells seeded in 96-well plates (5 × 10³ cells/well) and treated with YHAYGYTPQNVI (5.61 µM). MTT measurements were obtained on days 1, 5, and 7, and viability was expressed as a percentage relative to CT. Data are presented as mean ± SD. Statistical analyses were performed using Student’s t -test or ANOVA followed by Tukey’s test, with significance set at p