Abstract The omega-3 fatty acid, docosahexaenoic acid (DHA), has been shown to induce the proteasomal degradation of various cancer-associated molecules such as beta-catenin and estrogen receptor, implying its regulatory effect on proteasome. To verify this possible link between DHA and proteasome function, we explored the impacts of DHA on human papillomavirus-positive HeLa cervical cancer cells that constitutively express two known endogenous proteasome substrates E6 and E7 viral proteins. Exposure HeLa cells to DHA resulted in elevated proteasome activities along with decreased levels of E6/E7 viral proteins, and these effects of DHA were remarkably reversed in the presence of proteasome inhibitors, suggesting that DHA improves proteasome function in the cells and thereby accelerates the degradation of proteasome substrates. The DHA-induced increase in cellular proteasome activity was preceded by reactive oxygen species (ROS) overproduction and could be blocked by preincubation of the cells with ROS scavengers. Likewise, HeLa cells treated with exogenous ROS, H2O2, also exhibited significantly improved proteasome function. Unexpectedly, when the purified proteasome and whole-cell lysates isolated from HeLa cells were directly exposed to DHA or H2O2, such marked increases in proteasome activity were not seen. Taken together, these findings indicate that DHA may induce proteasome activation in cervical cancer cells mainly by indirect regulation of the proteasome. Citation Format: Kyu Lim, Kaipeng Jing, Soyeon Shin, Soyeon Jeong, Soyeon Kim, Gi-Ryang Kweon, Seung-Kiel Park, Tong Wu, Jong-Il Park. DHA may enhance proteasome activity in human cervical cancer cells: Indirect modulation of proteasome by DHA. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2255. doi:10.1158/1538-7445.AM2014-2255
Supplementary Figures S1-S3. from Apicularen A Induces Cell Death through Fas Ligand Up-Regulation and Microtubule Disruption by Tubulin Down-Regulation in HM7 Human Colon Cancer Cells
Abstract DNA topoisomerase II is a marker for the proliferation state of mammalian cells in culture, and the protein levels are markedly higher in exponentially growing cells than quiescent cells and can be downregulated by growth of the cells at high density and serum starvation. Correlation between ATF and TPA‐repressed DNA topoisomerase IIα (Topo IIα) mRNA has been investigated during TPA‐induced differentiation of HL‐60 cells. Topo IIα RNA and unknotting activity were reduced at 24 hours in TPA‐treated HL‐60 cells. The level of Topo IIα mRNA and the activity were gradually decreased in proportion to the concentration of TPA. Two DNA‐protein complexes were formed by DNA mobility shift assay when ATF‐binding site was incubated with nuclear extract prepared from TPA‐free HL‐60 cells, and the amount of ATF was vanished after TPA treatment. TPA‐repressed Topo IIα mRNA and ATF levels were partially restored after pretreatment of staurosporin. These results suggest that the reduced level of ATF may be important to the transcriptional repression of Topo IIα gene during TPA‐induced differentiation in HL‐60 cells and related to protein kinase C signal pathway.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)