Romanian Biotechnological Letters Vol. 16, No. 2, 2011 Copyright © 2011 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER 6080 IN VITRO activity of β-amirinic phytocompounds – a basic screening for breast cancer therapy Received for publication, July 9, 2010 Accepted, April 4, 2011 LAURA OLARIU, BRANDUSA DUMITRIU, ANCUTA NETOIU, MARIANA CONSTANTINOVICI, NATALIA ROSOIU S.C. Biotehnos S.A. – 3-5 Gorunului Street, 075100-Otopeni, Ilfov, Romania,Phone: +40317102402, Fax: +40317102400, e-mail: lolariu@biotehnos.com Abstract As a result of biotechnological research concerning the indigene phytotherapeutic potential follow-up, we obtained two β-amirinic compounds (GSO-1 and GSO-2) with antitumorous indications. In order to define the specific target action of these compounds, we developed an “in vitro” experimental model for antiproliferative status evaluation on adherent, epithelial type breast adenocarcinoma (MCF-7 cell line). The biocompounds were tested at different concentrations, at 24 and 48h cell culture treatment, as a screening of most important parameters for antitumorous activity (cell proliferation, DNA synthesis, apoptosis). The target parameters were obtained by cellular analysis methods as microscopy and flow cytometry, using competitive software. The results marked a significant and differentiated activity of GSO-1 and GSO-2. The first one is a relevant apoptosis inducer, but the second compound acts as an inhibitor for MCF-7 cells proliferation and DNA synthesis. Keywords: β-amirinic compounds, MCF-7 cell line, cell proliferation, DNA synthesis, apoptosis. Introduction Cancer patients usually receive chemotherapeutic agents during the course of their illness, treatment based on cell destruction potential by growth interruption. Many plants could have potent anticancer effects with soft adverse reaction and could be a natural source of very active pharmaceutical compounds (ex. vinblastine, vincristine, podophyllotoxin, taxol). The latter was extracted from species of the genus Taxus, constituting the most used antineoplastic agent at the present time [1]. However, the precise pathways through which these molecules produce an antitumor effect has not been yet fully characterized, also because their mechanism of action appears to be dependent to the type of tumor cell under study [2]. It has been reported that antitumoral drugs can act through different cellular mechanisms, e.g., by inducing apoptosis, cell-cycle arrest, or cell growth inhibition, but also by targeting angiogenesis and cell migration [3]. Tumourigenesis is the result of cell cycle disorganisation, leading to an uncontrolled cellular proliferation [4]. Specific cellular processes-mechanisms that control cell cycle progression and checkpoint traversation through the intermitotic phases are deregulated. Normally, these events are highly conserved due to the existence of conservatory mechanisms and molecules such as cell cycle genes and their products: cyclins, cyclin dependent kinases (Cdks), Cdk inhibitors (CKI) and extra cellular factors (i.e. growth factors) [5]. Revolutionary techniques using flow cytometry and specific software are available to quantify and evaluate cell cycle processes and cellular growth. S-phase fraction measurements, including ploidy values, using histograms and estimation of indices such as the mitotic index and tumour- doubling time indices, provide adequate information to the clinician to evaluate tumour aggressiveness, prognosis and the strategies for therapy in experimental researches [6], [7]. Apoptosis is a morphological and biochemical distinct form of programmed cell death that occurs in many cell types, MCF-7 being widely utilized to study this process. In apoptotic cells, phosphatidilserine (PS) - normaly found on the internal part of the membrane - becomes