Mistletoe lectin inhibits growth of Myc‐amplified small‐cell lung cancer

BACKGROUND: Small‐cell lung cancer (SCLC) is the deadliest form of lung cancer but lacks targeted therapies. METHODS: We studied the effect of the natural product mistletoe lectin (ML) in pre‐clinical models of SCLC, focusing on cell lines with amplification of the myc family oncogenes C‐myc and N‐myc. RESULTS: We found that ML treatment inhibits growth of SCLC cell lines in culture and induces apoptosis. ML treatment also decreases the expression of the amplified myc proteins. Over‐expression of either C‐myc or N‐myc results in enhanced SCLC cell sensitivity to ML. In a mouse xenograft model of SCLC, treatment with ML results in decreased tumor growth over 4 weeks with evidence of increased apoptosis in tumors from treated animals. CONCLUSION: Overall, our results demonstrate that ML exhibits therapeutic potential in SCLC, that is at least partially dependent on myc protein expression.