Sulforaphane Induces DNA Damage and Mitotic Abnormalities in Human Osteosarcoma MG-63 Cells: Correlation with Cell Cycle Arrest and Apoptosis
NUTRITION AND CANCER-AN INTERNATIONAL JOURNAL
Authors: Ferreira de Oliveira, Jose Miguel P.; Remedios, Catarina; Oliveira, Helena; Pinto, Pedro; Pinho, Francisco; Pinho, Sonia; Costa, Maria; Santos, Conceicao
Abstract
Osteosarcoma is a recalcitrant bone malignancy with poor responsiveness to treatments; therefore, new chemotherapeutic compounds are needed. Sulforaphane (SFN) has been considered a promising chemotherapeutic compound for several types of tumors by inducing apoptosis and cytostasis, but its effects (e.g., genotoxicity) in osteosarcoma cells remains exploratory. In this work, the MG-63 osteosarcoma cell line was exposed to SFN up to 20 mu M for 24 and 48h. SFN induced G(2)/M phase arrest and decreased nuclear division index, associated with disruption of cytoskeletal organization. Noteworthy, SFN induced a transcriptome response supportive of G(2)/M phase arrest, namely a decrease in Chk1- and Cdc25C-encoding transcripts, and an increase in Cdk1-encoding transcripts. After 48-h exposure, SFN at a dietary concentration (5 mu M) contributed to genomic instability in the MG-63 cells as confirmed by increased number of DNA breaks, clastogenicity, and nuclear and mitotic abnormalities. The increased formation of nucleoplasmic bridges, micronuclei, and apoptotic cells positively correlated with loss of viability. These results suggest that genotoxic damage is an important step for SFN-induced cytotoxicity in MG-63 cells. In conclusion, SFN shows potential to induce genotoxic damage at low concentrations and such potential deserves further investigation in other tumor cell types.
The Antiproliferative Activity of Oxypeucedanin via Induction of G(2)/M Phase Cell Cycle Arrest and p53-Dependent MDM2/p21 Expression in Human Hepatoma Cells
MOLECULES
Authors: Park, So Hyun; Hong, Ji-Young; Park, Hyen Joo; Lee, Sang Kook
Abstract
Oxypeucedanin (OPD), a furocoumarin compound from Angelica dahurica (Umbelliferae), exhibits potential antiproliferative activities in human cancer cells. However, the underlying molecular mechanisms of OPD as an anticancer agent in human hepatocellular cancer cells have not been fully elucidated. Therefore, the present study investigated the antiproliferative effect of OPD in SK-Hep-1 human hepatoma cells. OPD effectively inhibited the growth of SK-Hep-1 cells. Flow cytometric analysis revealed that OPD was able to induce G(2)/M phase cell cycle arrest in cells. The G(2)/M phase cell cycle arrest by OPD was associated with the downregulation of the checkpoint proteins cyclin B1, cyclin E, cdc2, and cdc25c, and the up-regulation of p-chk1 (Ser345) expression. The growth-inhibitory activity of OPD against hepatoma cells was found to be p53-dependent. The p53-expressing cells (SK-Hep-1 and HepG2) were sensitive, but p53-null cells (Hep3B) were insensitive to the antiproliferative activity of OPD. OPD also activated the expression of p53, and thus leading to the induction of MDM2 and p21, which indicates that the antiproliferative activity of OPD is in part correlated with the modulation of p53 in cancer cells. In addition, the combination of OPD with gemcitabine showed synergistic growth-inhibitory activity in SK-Hep-1 cells. These findings suggest that the anti-proliferative activity of OPD may be highly associated with the induction of G(2)/M phase cell cycle arrest and upregulation of the p53/MDM2/p21 axis in SK-HEP-1 hepatoma cells.