Related Experiment Video
Updated: Jun 20, 2026

Analyzing Tumor Gene Expression Factors with the CorExplorer Web Portal
Published on: October 11, 2019
Increased proteasome subunit protein expression and proteasome activity in colon cancer relate to an enhanced
A Arlt1, I Bauer, C Schafmayer
1Department of Internal Medicine, University-Hospital Schleswig-Holstein (UKSH)-Campus Kiel, Kiel, Germany.
Abstract:
An elevated proteasome activity contributes to tumorigenesis, particularly by providing cancer cells with antiapoptotic protection and efficient clearance from irregular proteins. Still, the underlying mechanisms are poorly known. In this study, we report that in colon cancer patients, higher proteasome activity was detected in tumoral tissue compared with surrounding normal tissue, and also that increased levels of proteasomal subunit proteins, such as S5a/PSMD4 and alpha-5/PSMA5, could be detected. Colon tumors showed higher nuclear levels of nuclear factor E2-related factor 2 (Nrf2), a transcription factor supposed to be involved in the control of proteasomal subunit protein expression. The induction or overexpression of Nrf2 led to stronger S5a and alpha-5 expression in the human colon cancer cell lines, Colo320 and Lovo, as well as in NCM460 colonocytes along with higher proteasome activity. The small interfering RNA (siRNA)-mediated Nrf2 knockdown decreased S5a and alpha-5 expression and reduced proteasome activity. Additionally, Nrf2-dependent S5a and alpha-5 expression conferred protection from tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, an effect preceded by an increased nuclear factor (NF)-kappaB activation and higher expression of antiapoptotic NF-kappaB target genes. These findings point to an important role of Nrf2 in the gain of proteasome activity, thereby contributing to colorectal carcinogenesis. Nrf2 may therefore serve as a potential target in anticancer therapy.
Related Concept Videos
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
Abnormal Proliferation
Cancer-Critical Genes I: Proto-oncogenes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
NF-kB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...