ABSTRACT
Cervical cancer is one of the most common cancers in women worldwide and it is a prominent cause of cancer mortality. Curcumin is one of the major compounds from Turmeric and has been shown to induce cytotoxic cell death in human cervical cancer cells. However, there is no study to show curcumin induced DNA damage action via the effect on the DNA damage and repair protein in cervical cancer cells in detail. In this study, we investigated whether or not curcumin induced cell death via DNA damage, chromatin condensation in human cervical cancer HeLa cells by using comet assay and DAPI staining, respectively, we found that curcumin induced cell death through the induction of DNA damage, and chromatin condensation. Western blotting and confocal laser microscopy examination were used to examine the effects of curcumin on protein expression associated with DNA damage, repair and translocation of proteins. We found that curcumin at 13 µM increased the protein levels associated with DNA damage and repair, such as O6-methylguanine-DNA methyltransferase, early-onset breast cancer 1 (BRCA1), mediator of DNA damage checkpoint 1, p-p53 and p-H2A.XSer140 in HeLa cells. Results from confocal laser systems microscopy indicated that curcumin increased the translocation of p-p53 and p-H2A.XSer140 from cytosol to nuclei in HeLa cells. In conclusion, curcumin induced cell death in HeLa cells via induction of DNA damage, and chromatin condensation in vitro.
Subject(s)
Curcumin/administration & dosage , DNA Damage/drug effects , DNA Repair/drug effects , Neoplasm Proteins/genetics , Uterine Cervical Neoplasms/drug therapy , Apoptosis/drug effects , BRCA1 Protein/genetics , Cell Proliferation/drug effects , Chromatin/genetics , Female , Gene Expression Regulation, Neoplastic/drug effects , HeLa Cells , Humans , Neoplasm Proteins/biosynthesis , O(6)-Methylguanine-DNA Methyltransferase/genetics , Tumor Suppressor Protein p53/genetics , Uterine Cervical Neoplasms/genetics , Uterine Cervical Neoplasms/pathologyABSTRACT
Expression of OLE16 and OLE18, two oleosin isoforms in oil bodies of rice seeds, was suppressed by RNA interference. Electron microscopy revealed a few large, irregular oil clusters in 35S::ole16i transgenic seed cells, whereas accumulated oil bodies in 35S::ole18i transgenic seed cells were comparable to or slightly larger than those in wild-type seed cells. Large and irregular oil clusters were observed in cells of double mutant seeds. These unexpected differences observed in oil bodies of 35S::ole16i and 35S::ole18i transgenic seeds were further analyzed. In comparison to wild-type plants, OLE18 levels were reduced to approximately 40% when OLE16 was completely eliminated in 35S::ole16i transgenic plants. In contrast, OLE16 was reduced to only 80% of wild-type levels when OLE18 was completely eliminated in 35S::ole18i transgenic plants. While the triacylglycerol content of crude seed extracts of 35S::ole16i and 35S::ole18i transgenic seeds was reduced to approximately 60% and 80%, respectively, triacylglycerol in isolated oil bodies was respectively reduced to 45% and 80% in accordance with the reduction of their oleosin contents. Oil bodies isolated from both 35S::ole16i and 35S::ole18i transgenic seeds were found to be of comparable size and stability to those isolated from wild-type rice seeds, although they were merely sheltered by a single oleosin isoform. The drastic difference between the triacylglycerol contents of crude seed extracts and isolated oil bodies from 35S::ole16i transgenic plants could be attributed to the presence of large, unstable oil clusters that were sheltered by insufficient amounts of oleosin and therefore could not be isolated together with stable oil bodies.
