ANTIPROLIFERATIVE ACTIVITY OF CYTOKININE DERIVATIVESAGAINST HCT-15 COLON AND MCF-7 BREAST CANCER CELLS:CELL CYCLE ANALYSIS AND BSA &DNA-BINDING STUDY

N6-Isopentenyladenosine (iPA) is a member of the cytokinins, a family of plant hormones that regulate plant cell growth and differentiation. iPA is present in mammalian cells in a free form, as a mononucleotide in the cytoplasm, or in a tRNA-bound form. Kinetin Riboside (KR) is devoid of cyclin-dependent kinase inhibitory activity and displayed potent antiproliferative activity against various human cancer cell lines and induced apoptosis in human myeloid leukemia cells. Earlier research has demonstrated that KR antiproliferative and apoptogenic activities are antagonized by pharmacological inhibitors of adenosine kinase (ADK), suggesting that KR bioactivation through metabolic conversion into the nucleotide form is essential for KR cytotoxicity. Apoptotic mechanism of iPA and KR led us to study in details the dose-dependent cell cycle arrest and apoptogenic effect of iPA and KR on MCF-7 breast and HCT-15 colon cell lines. On the other hand, cell cycle progression or apoptosis can be affected by activation of cell cycle checkpoints in response to DNA damage. We have also studied the interaction of iPA with DNA& BSA as a complementary information related to iPA antiproliferative activity.