Comparison of Anti-cancer Effects of Oleander Extract and Lycopene on Proliferation of Tamoxifen-Resistant Breast Cancer Cells


Ebrahim Azizi, Golamreza Amin, Talia Mazidi, Shirin Parvinroo and Mehrdad Iranshahi


Traditional & Complementary Medicine Exhibition 2007 (TCME 2007),Putra World Trade Centre (PWTC), Kuala Lumpur, Malaysia




Anticancer, oleandrin, lycopene


Oleandrin, a known cardiac glycoside fromNerium oleander L.and Lycopene, a known antioxidant red pigment of Tomato have shown inhibitory effects on growth of some cancer cells. Tamoxifen (TAM) is a widely used anti-estrogen that sometimes fails to exert its effects due to resistance development in breast tumor cells. Therefore, it is quite useful to establish resistant cells to study new anti-cancer compounds such as oleander extract and lycopene. The T47D cells that are resistant to 1uM of TAM (named  TAMR-6), were established in our lab by gradual exposure of parent T47D cells to increasing concentrations of TAM in their culture medium. The total hydroalcoholic extract of leaves ofNerium oleander L.and the lycopene extracted from freshly dried tomatoes were used to study their inhibitory effects alone or in combination with TAM on proliferation of TAMR-6 cells by trypan blue dye exclusion method. Statistical comparison of data for control and treatments indicated a dose-dependent inhibitory effect of both compounds on proliferation of TAMR-6 cells. Oleander extract at 1 mg/ml or lycopene at 1 x 10-5M significantly (P< 0.001) reduced cell proliferation. Lycopene at 5 x 10-6 M had almost the same inhibitory effect on cell proliferation as TAM at 1 x 10-6M. There were synergistic inhibitory effects between oleander extract or lycopene with TAM. Therefore, despite their different potency, the oleander extract and lycopene are good anti-cancer candidates for further evaluation in breast cancer therapy, particularly in case of tumor resistance.