Amiloride synergizes with EGFR PROTACs and inhibitors to overcome therapeutic resistance in NSCLC

》》文章原文链接：Amiloride synergizes with EGFR PROTACs and inhibitors to overcome therapeutic resistance in NSCLC

》》Journal：Bioorganic Chemistry 

》》相关产品：Amiloride hydrochloride (SJ-MX1026)

》》产品引用描述：

》》Abstract：

Lung cancer remains the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for most cases. Among NSCLC patients, approximately 15-30 % harbor activating mutations in the Epidermal Growth Factor Receptor (EGFR), making them eligible for treatment with tyrosine kinase inhibitors (TKIs) like osimertinib, which has shown significant therapeutic benefits. However, acquired resistance to these therapies remains a major challenge in improving long-term clinical outcomes, underscoring the urgent need for novel strategies to address treatment resistance. In this study, we investigated the therapeutic potential of Amiloride (MK-870), a sodium channel inhibitor, as an adjuvant to EGFR-targeted therapies for NSCLC. Our findings demonstrate that MK-870 exhibits synergistic effects with EGFR PROTACs and small-molecule inhibitors, significantly enhancing antitumor activity in NSCLC cell lines. We identified α-ENaC (encoded by SCNN1A) as a key regulator of EGFR stability, with high α-ENaC expression correlating with reduced sensitivity to EGFR. MK-870 achieves dual downregulation of EGFR at both transcriptional and protein levels via targeted inhibition of sodium channel proteins. Furthermore, MK-870 enhances lysosomal activity in multiple NSCLC cell lines and EGFR-overexpressing NIH/3 T3 cells-a phenomenon potentially linked to its inhibition of sodium‑hydrogen exchanger (NHE) to promote cellular acidification. Mechanistically, the resultant acidification promotes apoptosis while simultaneously enhancing lysosome-mediated degradation of EGFR proteins by PROTAC molecules. Collectively, MK-870 synergizes with EGFR-targeting agents through coordinated modulation of sodium channel proteins and NHE-mediated pH homeostasis. These novel insights highlight MK-870 as a promising adjuvant for overcoming EGFR-targeted therapeutic resistance in NSCLC, offering a new avenue for improving patient outcomes in this challenging disease.

》》部分实验数据展示：

Fig. 1.  Amiloride induces degradation of EGFR mutants via the proteasome and lysosome. A. The chemical structure of Amiloride (also referred to as MK-870).B. MK-870 degrades EGFRL858R/T790M/C797S triple mutant proteins with high concentrations (≥ 0.3 mM). NIH/3 T3 EGFRLTC cells were treated with the indicated concentrations of MK-870 for 24 h, followed by the detection of total and phosphorylated levels of EGFR and AKT proteins. C- E. MK-870 degrades EGFR mutant variants in H1975 (EGFR^L858R/T790M), HCC827 (EGFR^ex19del), and PB1 (EGFRex19del/T790M) cells but not EGFRWT in A549 cells with the high concentration (0.5 mM). These cells were treated with the indicated concentrations of MK-870 for 24 h or longer, followed by detecting EGFR protein levels. F. NIH/3 T3 EGFRLTC cells were pre-incubated with 1 μM Carfilzomib, Bafilomycin A1, or MLN4924 for 2 h, followed by treatment with 0.5 mM MK-870 for 24 h, and EGFR protein levels were detected.