The c-Src/LIST Positive Feedback Loop Sustains Tumor Progression and Chemoresistance.

Chemotherapy resistance and treatment failure hinder clinical cancer treatment. Src, the first mammalian proto-oncogene to be discovered, is a valuable anti-cancer therapeutic target. Although several c-Src inhibitors have reached the clinical stage, drug resistance remains a challenge during treatment. Herein, a positive feedback loop between a previously uncharacterized long non-coding RNA (lncRNA), which the authors renamed lncRNA-inducing c-Src tumor-promoting function (LIST), and c-Src is uncovered. LIST directly binds to and regulates the Y530 phosphorylation activity of c-Src. As a c-Src agonist, LIST promotes tumor chemoresistance and progression in vitro and in vivo in multiple cancer types. c-Src can positively regulate LIST transcription by activating the NF-κB signaling pathway and then recruiting the P65 transcription factor to the LIST promoter. Interestingly, the LIST/c-Src interaction is associated with evolutionary new variations of c-Src. It is proposed that the human-specific LIST/c-Src axis renders an extra layer of control over c-Src activity. Additionally, the LIST/c-Src axis is of high physiological relevance in cancer and may be a valuable prognostic biomarker and potential therapeutic target.