Related Experiment Video
Updated: Oct 3, 2026
Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
Published on: January 7, 2013
Enzyme activity and protein content of superoxide dismutase isozymes in human renal cell carcinoma
S Homma-Takeda1, A Sasaki, M Kikushima
1Graduate School Doctoral Program in Medical Sciences, Institute of Community Medicine, University of Tsukuba, Ibaraki , Japan.
Abstract:
Alterations in renal superoxide dismutase (SOD) isozymes were examined in cancerous tissues of human renal cell carcinoma and the corresponding non-cancerous renal tissues. Cu,Zn-SOD activities in cancerous tissues were lower than those in normal tissues. Mn-SOD activities were varied in the cases examined, whereas no significant difference between cancerous and normal tissues was observed for Mn- or total-SOD activities. Immunoblot analysis showed that the loss in enzyme activity in cancerous tissue was greater than the decrease in protein content for either isozyme. The selective decrease in Cu,Zn-SOD activities in cancerous tissue observed in this study suggests that the cytoplasmic defense against free radical damage appears to be reduced in renal cell carcinoma.
Insights
Human renal cell carcinoma shows reduced copper, zinc-superoxide dismutase (Cu,Zn-SOD) activity in cancerous tissues compared to normal kidney tissue. This suggests a weakened defense against free radical damage in these cancer cells.
Area of Science:
- Biochemistry
- Oncology
- Molecular Biology
Background:
- Renal cell carcinoma (RCC) is the most common type of kidney cancer.
- Superoxide dismutase (SOD) isozymes are crucial antioxidant enzymes involved in cellular defense against reactive oxygen species.
- Alterations in SOD isozyme activity may play a role in the development and progression of RCC.
Purpose of the Study:
- To investigate the alterations in superoxide dismutase (SOD) isozyme activities and protein levels in human renal cell carcinoma tissues compared to non-cancerous renal tissues.
- To determine the specific SOD isozymes affected in RCC and their potential contribution to oxidative stress.
Main Methods:
- Enzyme activity assays were performed on cancerous and non-cancerous human renal tissues.
- Immunoblot analysis was used to quantify the protein levels of SOD isozymes.
- Comparison of enzyme activity and protein content was conducted for Cu,Zn-SOD and Mn-SOD.
Main Results:
- Cu,Zn-SOD enzyme activity was significantly lower in cancerous renal tissues than in normal tissues.
- Mn-SOD activity showed variations but no significant overall difference between cancerous and normal tissues.
- Immunoblot analysis indicated that the decrease in Cu,Zn-SOD activity in cancerous tissues was disproportionately larger than the decrease in its protein content.
Conclusions:
- The selective decrease in Cu,Zn-SOD activity in renal cell carcinoma suggests a compromised cytoplasmic antioxidant defense system.
- Reduced Cu,Zn-SOD function may contribute to increased oxidative stress and cellular damage in RCC.
- These findings highlight the potential role of Cu,Zn-SOD in the pathogenesis of renal cell carcinoma.
