A new A₄₃₁/cell membrane chromatography and online high performance liquid chromatography/mass spectrometry method for screening epidermal growth factor receptor antagonists from Radix sophorae flavescentis

The intracellular kinase domains of epidermal growth factor receptor (EGFR) in some tumor cells such as human epidermal squamous cells (A₄₃₁ cells) are an important target for drug discovery. We have developed a new A₄₃₁/cell membrane chromatography (A₄₃₁/CMC)-online-high performance liquid chromatography/mass spectrometry (HPLC/MS) method for screening EGFR antagonists from medicinal herbs such as traditional Chinese medicines (TCMs). In this study, A₄₃₁ cells with high EGFR expression levels were used to prepare cell membrane stationary phase (CMSP) in an A₄₃₁/CMC model. The retention fractions eluted from the CMSP column were enriched onto an ODS pre-column and then switched into an HPLC/MS system by combining a 10 port columns switching valve. The screening results found that oxymatrine and matrine from Radix sophorae flavescentis (RSF) were the targeted components which could act on EGFR in similar manner of gefitinib as a control drug. There was a good relationship of their inhibiting effects on EGFR secretion and A₄₃₁ cell growth in vitro. This new A₄₃₁/CMC-online-HPLC/MS method can be applied for screening EGFR antagonists from TCMs such as RSF. It will be a useful method for drug discovery with natural medicinal herbs as a leading compound resource.