Oleuropein Mediated Targeting of Signaling Network in Cancer

Cancer is a multifaceted and genomically complex disease. Rapidly accumulating preclinical and clinical studies are emphasizing on wide ranging molecular mechanisms that underpin cancer development, progression and metastasis. Intratumor heterogeneity, loss of apoptosis, rapidly developing resistance against molecular therapeutics and off-target effects are some of the deeply studied resistance mechanisms. Data obtained through high-throughput technologies has considerably enhanced our understanding of the intracellular signaling cascades frequently dysregulated spatio-temporally. There is an ever-expanding list of synthetic and natural agents reported to activate tumor suppressor genes and inhibit oncogenes in cancer cells. Markedly reduced tumor growth has also been documented in xenografted mice administered with phytochemicals. Oleuropein is a bioactive ingredient isolated from various sources and there is evidence of complete regression of tumors in 9- 12 days in mice orally administered with Oleuropein. In this review we summarize recent developments in use of Oleuropein as an anticancer agent. Extraction and isolation of Oleuropein and how it modulates intracellular signaling network to induce apoptosis in cancer cells. Human epidermal growth factor receptor 2 (HER2) frequently overexpressed in breast cancer cells is inhibited by Oleuropein. Interestingly, trastuzumab efficacy was notably enhanced in Oleuropein treated breast cancer cells. There is still insufficient information related to Oleuropein mediated microRNA regulation in cancer cells. We still do not have information about regulation of different signaling cascades by Oleuropein which are deregulated in cancer. Future studies must converge on a deeper analysis of target molecular network of Oleuropein and its efficacy as a tumor growth inhibitor in xenografted mice.