ABSTRACT
Aim: Rubiaceae is one of the largest families of plants and it includes the Jamaican genus Portlandia. This family has been used in several ethnomedicinal practices. Thus, in this study we investigated whether extracts of two species of Portlandia affect In vitro proliferation of breast cancer cells. Study Design: Metastatic (MDA-MB-231 and HeLa) cells were incubated in the absence or in the presence of Portlandia extracts. A human non-metastatic (MCF-10A) and normal (ATCC PCS-600-010) epithelial cell lines were used as control. Methodology: At the end of the study all cell lines were incubated with Portlandia extracts (-and its subfractions-) and then analyzed on proliferation, thymidine incorporation and mitogenic and survival signaling pathways on metastatic and non-metastatic cells. Results: It was found that Portlandia methanol extract inhibited proliferation of MDA-MB- 231 in a dose-dependent manner attenuating the phosphorylation of Erk1/2 and Akt1 without affecting the proliferation of MCF-10A cells. [3H] thymidine incorporation was also decreased by Portlandia methanol extract. This study suggests that Portlandia extracts selectively affected the proliferation of metastatic breast cancer cells through the modulation of Erk1/2 and Akt1 activities that play a critical role during cell survival and proliferation. Conclusion: Portlandia leaf extracts contain active compounds, which strongly repress cancer cell proliferation in a dose-dependent manner and selectively down-regulate phosphorylation of both Erk1/2 and Akt1 activities.