The proteasome can be thought of as the cell’s recycling center. It is a structure within the cell where proteins that have fulfilled their immediate function are broken down (degraded). You can see illusations o the proteasome and read more about it at this wikipedia link.
The Proteasome enables cells to regulate the concentration of particular proteins and degrade misfolded proteins. Proteasome inhibitors have effective anti-tumor activity in cell culture, inducing apoptosis by disrupting the regulated degradation of pro-growth cell cycle proteins.
Dr. Anette Duensing has done research using GIST cell lines that suggests that proteasome inhibition might be helpful against gastrointestinal stromal tumor (GIST). See our news story about her work.