The EGFR tyrosine kinase inhibitor osimertinib has been approved for the first-line treatment of EGFR-mutated Non-Small Cell Lung Cancer (NSCLC) patients. Despite its efficacy, patients develop resistance. Mechanisms of resistance are heterogeneous and not fully understood, and their characterization is essential to find new strategies to overcome resistance. Ceramides are well-known regulators of apoptosis and are converted into glucosylceramides (GlcCer) by glucosylceramide synthase (GCS). A higher content of GlcCers was observed in lung pleural effusions from NSCLC patients and their role in osimertinib-resistance has not been documented. The aim of this study was to determine the therapeutic potential of inhibiting GCS in NSCLC EGFR-mutant models resistant to osimertinib in vitro and in vivo. Lipidomic analysis showed a significant increase in the intracellular levels of glycosylceramides, including GlcCers in osimertinib resistant clones compared to sensitive cells. In resistant cells, the GCS inhibitor PDMP caused cell cycle arrest, inhibition of 2D and 3D cell proliferation, colony formation and migration capability, and apoptosis induction. The intratumoral injection of PDMP completely suppressed the growth of OR xenograft models. This study demonstrated that dysregulation of ceramide metabolism is involved in osimertinib-resistance and targeting GCS may be a promising therapeutic strategy for patients progressed to osimertinib.

EGFR酪氨酸激酶抑制剂奥希替尼已被批准用于EGFR突变非小细胞肺癌（NSCLC）患者的一线治疗。尽管它有效，但患者会产生耐药性。耐药机制多种多样且尚未完全了解，其表征对于寻找克服耐药性的新策略至关重要。神经酰胺是众所周知的细胞凋亡调节剂，并通过葡萄糖神经酰胺合酶 (GCS) 转化为葡萄糖神经酰胺 (GlcCer)。在 NSCLC 患者的肺胸腔积液中观察到 GlcCers 含量较高，但其在奥希替尼耐药中的作用尚未有记录。本研究的目的是确定在体外和体内对奥希替尼耐药的 NSCLC EGFR突变模型中抑制 GCS 的治疗潜力。脂质组学分析显示，与敏感细胞相比，奥希替尼耐药克隆中糖基神经酰胺（包括 GlcCers）的细胞内水平显着增加。在耐药细胞中，GCS 抑制剂 PDMP 导致细胞周期停滞，抑制 2D 和 3D 细胞增殖、集落形成和迁移能力以及诱导细胞凋亡。瘤内注射PDMP完全抑制OR异种移植模型的生长。这项研究表明，神经酰胺代谢失调与奥希替尼耐药有关，针对进展为奥希替尼的患者，靶向 GCS 可能是一种有前景的治疗策略。