ABSTRACT
PURPOSE: The unmanageable side effects caused by current chemotherapy regimens to treat cancer are an unresolved problem. Although many phytonutrients are useful as chemoprevention without side effects, their effects are slower and smaller than conventional chemotherapy. In the present work, we examined the cumulative effect of two phytonutrients, curcumin and citral, on breast cancer cell lines and compared their effect with the known chemotherapy regimen of cyclophosphamide, methotrexate, and 5-fluorouracil. METHODS: Using cultured breast cancer and normal epithelial cells, the cytotoxic and apoptotic effect of curcumin and citral was evaluated in vitro. The synergistic effect of curcumin and citral was calculated by a combination index study using the method by Chou and Talalay. Cell death pathways and mechanisms were analyzed by measuring intracellular reactive oxygen species (ROS) and apoptotic protein levels. RESULTS: Curcumin and citral caused dose and time dependent cell death and showed a synergistic effect at effective concentration EC50 and above concentrations in breast cancer cells without disturbing normal breast epithelial cells. With combination curcumin and citral treatment, apoptosis induction and cell cycle arrest at G0/G1 phase in breast cancer cells were observed. Curcumin and citral generated ROS and activated p53 and poly (ADP-ribose) polymerase-1 mediated apoptotic pathways. CONCLUSION: The results of this study suggest that curcumin and citral in combination may be a useful therapeutic intervention for breast cancer.
ABSTRACT
In systemic therapy, chemotherapeutic drugs, often, cause considerable side effects; and combination of natural compounds lessen the extent of such effects. In the present study, combined effect of citral and 5-fluorouracil was studied in Schizosaccharomyces pombe cells. The antagonistic combination index found was at 0.01 and 0.025 mM of citral with 40 µg or higher concentration of 5-fluorouracil. The combined treatment was so effective that higher number of cells underwent apoptosis compared to individual treatment of 5-fluorouracil. Citral controlled ROS levels and increased survival of normal cells. Several differentially expressed proteins observed in the citral treatment could further help understanding its mechanism of action.
Subject(s)
Fluorouracil/antagonists & inhibitors , Monoterpenes/pharmacology , Reactive Oxygen Species/metabolism , Schizosaccharomyces/drug effects , Acyclic Monoterpenes , Apoptosis/drug effects , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Fluorouracil/toxicity , Fungal Proteins/analysis , Oxidative Stress/drug effects , Schizosaccharomyces/growth & development , Schizosaccharomyces/metabolismABSTRACT
A wide variety of natural compounds exists that possesses significant cytotoxic as well as chemopreventive activity through induction of apoptosis in cancer cells. The antiproliferative and apoptotic effect of L-carvone, an active component of spearmint (Mentha spicata) was studied on breast cancer (MCF 7 and MDA MB 231) and normal (MCF 10A) cell lines, and insight into its mechanism of action was attained. L-carvone inhibited proliferation of MCF 7 (IC50 1.2 mM) and MDA MB 231 cells (IC50 1.0 mM) and inhibited the migration of breast cancer cell lines. L-carvone induced apoptosis as observed by nuclei fragmentation and the presence of apoptotic bodies in DAPI, AnnexinV/propidium iodide, and TUNEL assays. L-carvone exposure arrested MCF 7 cells in S phase of the cell cycle. DNA damage caused by L-carvone was apparent from the increased tail moment in COMET assay, which could be induced by an increase in ROS that was measured using a fluorescence probe. Glutathione levels were also increased. The increased level of p53, Bad, cleaved caspase 3, and cleaved PARP explained p53 and caspase-mediated apoptosis.
