MG-132
133407-82-6 (carbobenzoxy-Leu-Leu-leucinal) as a peptide aldehyde effectively blocks the proteolytic activity of proteasome complex.9 Proteasome inhibitors including MG132 have been shown to induce apoptotic cell death through formation of ROS. ROS formation and GSH depletion due to proteasome inhibitors may cause mitochondrial dysfunction and subsequent cytochrome c release, which leads to cell viability loss1, 2.
MG132 dose dependently inhibited the growth of A549 cells with an IC50 of approximately 20 µM. MG132 also reduced the growth of human cervical HeLa cancer cells with an IC50 of approximately 5 µM. Treatment with 0.5 µM MG132 significantly decreased the growth of HeLa cells and induced cell death as well. Cell growth inhibition by MG132 depends on incubation doses of that and cell types3.
MG132 significantly induced a G1 phase arrest of the cell cycle. It inhibits the growth of HT-29 colon cancer cells via inducing G2/M cell cycle arrest4, causes MG-63 osteosarcoma cell arrest at G2/M phase5, prolongs the duration of G0/G1 arrest in MnCl2-treated A549 cells21 and induces a G1 arrest in gastric carcinoma cells6. Deregulation of the ubiquitin-proteasomal system by MG132 can result in different cell cycle phase arrests depending on various cancer cell lines.
Proteasome inhibitors including MG132 have been shown to induce apoptotic cell death through formation of ROS1, 2, 7. MG132 inhibited the growth of human A549 cells via inducing the cell cycle arrest as well as triggering apoptosis, which was in part correlated with the changes of ROS and GSH levels.
References:
1. Ling YH, Liebes L, Zou Y and Perez-Soler R. Reactive oxygen species generation and mitochondrial dysfunction in the apoptotic response to Bortezomib, a novel proteasome inhibitor, in human H460 non-small cell lung cancer cells, 2003; 278: 33714–33723.
2. Qiu JH, Asai A, Chi S, et al. Proteasome inhibitors induce cytochrome c-caspase-3-like protease-mediated apoptosis in cultured cortical neurons. J Neurosci 2000; 20: 259–265.
3. YH. Han, WH. Park, MG132 as a proteasome inhibitor induces cell growth inhibition and cell death in A549 lung cancer cells via influencing reactive oxygen species and GSH level, Human and Experimental Toxicology, 29(7) 607–614.
4. Wu WK, Wu YC, Yu L, et al. Induction of autophagy by proteasome inhibitor is associated with proliferative arrest in colon cancer cells. Biochem Biophys Res Commun 2008; 374: 258–263.
5. Yan XB, Yang DS, Gao X, et al. Caspase-8 dependent osteosarcoma cell apoptosis induced by proteasome inhibitor MG132. Cell Biol Int 2007; 31: 1136–1143.
6. ZhangW, Tong Q, Li S, Wang X andWang Q.MG-132 inhibits telomerase activity, induces apoptosis and G(1) arrest associated with upregulated p27kip1 expression and downregulated survivin expression in gastric carcinoma cells. Cancer Invest 2008; 26:1032–1036.
7. Wu HM, Chi KH, Lin WW. Proteasome inhibitors stimulate activator protein-1 pathway via reactive oxygen species production. FEBS Lett 2002; 526: 101–105.
