Targeting multiple key signaling pathways in melanoma using leelamine

Raghavendra Gowda, Subba Rao V Madhunapantula, Omer Kuzu, Arati Sharma, Gavin P. Robertson

Research output: Contribution to journalArticle

27 Citations (Scopus)


Melanoma is a highly drug-resistant cancer with resistance developing to agents targeting single proteins. To circumvent this problem, a new class of agent inhibiting multiple key pathways important in this disease is being developed to reduce the likelihood of developing resistant disease. The phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), and STAT3 pathways are constitutively activated in 50% to 70% of melanomas, promoting disease development. To identify a drug simultaneously targeting the PI3K, MAPK, and STAT3 cascades, a natural product library was screened to identify leelamine as a potential inhibitor. Leelamine was 4.5-fold more effective at inhibiting cultured melanoma cell survival than normal cells, with average IC50 values of 2 and 9.3 μmol/L, respectively. It inhibited cellular proliferation at a concentration of 2.5 μmol/L by 40% to 80% and longer exposure increased apoptosis 600%. Leelamine inhibited the growth of preexisting xenografted melanoma tumors by an average of 60% by targeting the PI3K, MAPK, and STAT3 pathways without affecting animal body weight or blood markers of major organ function. The mechanism of action of leelamine is mediated by disruption of cholesterol transport, causing decreased cellular proliferation and consequently leading to increased tumor cell apoptosis as well as decreased tumor vascularization. Thus, a unique agent and novel mechanismof action has been identified for the treatment of melanoma that acts by inhibiting the activity of three major signaling pathways regulating the development of this disease.

Original languageEnglish
Pages (from-to)1679-1689
Number of pages11
JournalMolecular Cancer Therapeutics
Issue number7
Publication statusPublished - 1 Jan 2014
Externally publishedYes


ASJC Scopus subject areas

  • Oncology
  • Cancer Research
  • Medicine(all)

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