Novel Luciferase-Based Reporter System to Monitor Activation of ErbB2/Her2/neu Pathway Noninvasively During Radiotherapy

Purpose To develop a split-luciferase–based reporter system that allows for noninvasive monitoring of activation of the Her2/neu pathway in vivo in a quantitative and sensitive manner. Methods and Materials Fusion proteins of the ErbB2/Her2/neu receptor to the N-terminal fragment of luciferase and of its downstream binding partner Shc to the C-terminal fragment of luciferase have been engineered owing to the rationale that on activation and binding of the Her2 receptor molecule to Shc, luciferase function will be reconstituted. Thus, the resulting bioluminescence signals can serve as a surrogate measure of receptor activation. Results We have shown that our reporter systems functions well in vitro in breast cancer cells and in vivo in xenograft tumors. In particular, the activities of Her2/neu in xenograft tumors could be monitored serially for an extended period after radiotherapy. Conclusions We believe that the novel ErbB2/Her2/neu reporter we have presented is a powerful tool to study the biology of the Her2-neu pathway in vitro and in vivo . It should also facilitate the development and rapid evaluation of new Her2/neu-targeted therapeutic agents.