Microtiter cell-based assay for detection of agents that alter cellular levels of Her2 and EGFR

Overexpression of the transmembrane tyrosine kinases Her2 and EGFR is associated with aggressive malignancies, and several therapeutic strategies targeting the two receptors are now in various stages of clinical development. Most of the known agents block the activation or inhibit the activity of the kinases; however, a more significant therapeutic outcome may result from degrading these oncoproteins. Here, we report the development of a microtiter cell-based assay that sensitively detects cellular levels of Her2 and EGFR. The assay is useful in identifying small molecules that alter cellular levels of these kinases and in quantifying their effect. The method gives results comparable to Western blot, but it is faster, less labor intensive, and amenable to high throughput.